Дисертації: "Australian marsupials"

1

com, Nevi Parameswaran@gmail, and Nivethitha (Nevi) Parameswaran. "Toxoplasma gondii in Australian Marsupials." Murdoch University, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20100203.145857.

Повний текст джерела

Анотація:

Diagnostic tools were developed and utilised to detect Toxoplasma gondii infection in a range of Australian marsupial species and identify epidemiological trends. An ELISA was developed to detect anti-T. gondii IgG in macropod marsupials. When compared with the commercially available MAT (modified agglutination test), the ELISA was in high agreement and yielded a ê coefficient of 0.96. Of 18 western grey kangaroos (Macropus fuliginosus) tested for the presence of T. gondii DNA by PCR, the 9 ELISA positive kangaroos tested PCR positive and the 9 ELISA negative kangaroos tested PCR negative indicating that the ELISA protocol was both highly specific and sensitive and correlated 100% with the more labour intensive PCR assay. A T. gondii seroprevalence study was undertaken on free ranging Australian marsupials. There was a T. gondii seroprevalence of 15.5% (95%CI: 10.7-20.3) in western grey kangaroos located in the Perth metropolitan area. The T. gondii seroprevalence in male western grey kangaroos was significantly less than their female counterparts (p=0.038), which may be related to behavioural differences causing differences in exposure to oocysts or recrudescence of T. gondii infection in pregnant females. Marsupial populations located in islands free from felids had a low overall T. gondii seroprevalence. A case control study determined that marsupials located in areas where felids may roam are 14.20 (95%CI: 1.94-103.66) times more likely to be T. gondii seropositive than marsupials located on felid-free islands. PCR, immunohistochemistry and serological techniques were used to detect T. gondii infection in marsupial dams and their offspring. T. gondii DNA was detected in the pouch young of chronically infected western grey kangaroos and a woylie (Bettongia penicillata). T. gondii DNA was also identified in the mammary gland of the woylie dam suggesting that infection of the woylie pouch young was from suckling milk from the mammary gland. Results of the study demonstrate that vertical transmission of T. gondii occurs in Australian marsupials and may be of importance in the maintenance of T. gondii infection in Australian marsupial populations. Animal tissue and meat from Australia, predominately from Australian marsupials, were screened for T. gondii DNA using PCR primers for the multi-copy, T. gondii specific B1 gene. Sequencing of the B1 gene revealed atypical genotypes in 7 out of 13 samples from Australia. These 7 isolates contained single nucleotide polymorphisms (SNPs) in the B1 gene that could not be matched with known sequences from strains I, II, III and X. Six unique genotypes were identified out of the 7 atypical isolates; two out of the 7 isolates had the same unique sequence at the B1 gene whereas the other 5 isolates each had different combinations of SNPs at the B1 gene. A majority of T. gondii isolates sampled from native Australian marsupials were of an atypical genotype. The discovery of atypical strains of T. gondii in Australia leads to further questions regarding the origin and transmission of these atypical strains. Additional studies linking atypical strains with their clinical manifestation are also warranted.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Parameswaran, Nevi. "Toxoplasma gondii in Australian marsupials /." Murdoch University Digital Theses Program, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20100203.145857.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Fuss, Janet Megan. "Retinal anatomy of Australian marsupials /." Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09SM/09smf994.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Parameswaran, Nivethitha (Nevi). "Toxoplasma gondii in Australian Marsupials." Thesis, Parameswaran, Nivethitha (Nevi) (2008) Toxoplasma gondii in Australian Marsupials. PhD thesis, Murdoch University, 2008. https://researchrepository.murdoch.edu.au/id/eprint/1680/.

Повний текст джерела

Анотація:

Diagnostic tools were developed and utilised to detect Toxoplasma gondii infection in a range of Australian marsupial species and identify epidemiological trends. An ELISA was developed to detect anti-T. gondii IgG in macropod marsupials. When compared with the commercially available MAT (modified agglutination test), the ELISA was in high agreement and yielded a ê coefficient of 0.96. Of 18 western grey kangaroos (Macropus fuliginosus) tested for the presence of T. gondii DNA by PCR, the 9 ELISA positive kangaroos tested PCR positive and the 9 ELISA negative kangaroos tested PCR negative indicating that the ELISA protocol was both highly specific and sensitive and correlated 100% with the more labour intensive PCR assay. A T. gondii seroprevalence study was undertaken on free ranging Australian marsupials. There was a T. gondii seroprevalence of 15.5% (95%CI: 10.7-20.3) in western grey kangaroos located in the Perth metropolitan area. The T. gondii seroprevalence in male western grey kangaroos was significantly less than their female counterparts (p=0.038), which may be related to behavioural differences causing differences in exposure to oocysts or recrudescence of T. gondii infection in pregnant females. Marsupial populations located in islands free from felids had a low overall T. gondii seroprevalence. A case control study determined that marsupials located in areas where felids may roam are 14.20 (95%CI: 1.94-103.66) times more likely to be T. gondii seropositive than marsupials located on felid-free islands. PCR, immunohistochemistry and serological techniques were used to detect T. gondii infection in marsupial dams and their offspring. T. gondii DNA was detected in the pouch young of chronically infected western grey kangaroos and a woylie (Bettongia penicillata). T. gondii DNA was also identified in the mammary gland of the woylie dam suggesting that infection of the woylie pouch young was from suckling milk from the mammary gland. Results of the study demonstrate that vertical transmission of T. gondii occurs in Australian marsupials and may be of importance in the maintenance of T. gondii infection in Australian marsupial populations. Animal tissue and meat from Australia, predominately from Australian marsupials, were screened for T. gondii DNA using PCR primers for the multi-copy, T. gondii specific B1 gene. Sequencing of the B1 gene revealed atypical genotypes in 7 out of 13 samples from Australia. These 7 isolates contained single nucleotide polymorphisms (SNPs) in the B1 gene that could not be matched with known sequences from strains I, II, III and X. Six unique genotypes were identified out of the 7 atypical isolates; two out of the 7 isolates had the same unique sequence at the B1 gene whereas the other 5 isolates each had different combinations of SNPs at the B1 gene. A majority of T. gondii isolates sampled from native Australian marsupials were of an atypical genotype. The discovery of atypical strains of T. gondii in Australia leads to further questions regarding the origin and transmission of these atypical strains. Additional studies linking atypical strains with their clinical manifestation are also warranted.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Parameswaran, Nivethitha (Nevi). "Toxoplasma gondii in Australian Marsupials." Parameswaran, Nivethitha (Nevi) (2008) Toxoplasma gondii in Australian Marsupials. PhD thesis, Murdoch University, 2008. http://researchrepository.murdoch.edu.au/1680/.

Повний текст джерела

Анотація:

Diagnostic tools were developed and utilised to detect Toxoplasma gondii infection in a range of Australian marsupial species and identify epidemiological trends. An ELISA was developed to detect anti-T. gondii IgG in macropod marsupials. When compared with the commercially available MAT (modified agglutination test), the ELISA was in high agreement and yielded a ê coefficient of 0.96. Of 18 western grey kangaroos (Macropus fuliginosus) tested for the presence of T. gondii DNA by PCR, the 9 ELISA positive kangaroos tested PCR positive and the 9 ELISA negative kangaroos tested PCR negative indicating that the ELISA protocol was both highly specific and sensitive and correlated 100% with the more labour intensive PCR assay. A T. gondii seroprevalence study was undertaken on free ranging Australian marsupials. There was a T. gondii seroprevalence of 15.5% (95%CI: 10.7-20.3) in western grey kangaroos located in the Perth metropolitan area. The T. gondii seroprevalence in male western grey kangaroos was significantly less than their female counterparts (p=0.038), which may be related to behavioural differences causing differences in exposure to oocysts or recrudescence of T. gondii infection in pregnant females. Marsupial populations located in islands free from felids had a low overall T. gondii seroprevalence. A case control study determined that marsupials located in areas where felids may roam are 14.20 (95%CI: 1.94-103.66) times more likely to be T. gondii seropositive than marsupials located on felid-free islands. PCR, immunohistochemistry and serological techniques were used to detect T. gondii infection in marsupial dams and their offspring. T. gondii DNA was detected in the pouch young of chronically infected western grey kangaroos and a woylie (Bettongia penicillata). T. gondii DNA was also identified in the mammary gland of the woylie dam suggesting that infection of the woylie pouch young was from suckling milk from the mammary gland. Results of the study demonstrate that vertical transmission of T. gondii occurs in Australian marsupials and may be of importance in the maintenance of T. gondii infection in Australian marsupial populations. Animal tissue and meat from Australia, predominately from Australian marsupials, were screened for T. gondii DNA using PCR primers for the multi-copy, T. gondii specific B1 gene. Sequencing of the B1 gene revealed atypical genotypes in 7 out of 13 samples from Australia. These 7 isolates contained single nucleotide polymorphisms (SNPs) in the B1 gene that could not be matched with known sequences from strains I, II, III and X. Six unique genotypes were identified out of the 7 atypical isolates; two out of the 7 isolates had the same unique sequence at the B1 gene whereas the other 5 isolates each had different combinations of SNPs at the B1 gene. A majority of T. gondii isolates sampled from native Australian marsupials were of an atypical genotype. The discovery of atypical strains of T. gondii in Australia leads to further questions regarding the origin and transmission of these atypical strains. Additional studies linking atypical strains with their clinical manifestation are also warranted.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Zabaras, Regina, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "The evolution of semiochemicals in Australian marsupials." THESIS_CSTE_SFH_Zabaras_R.xml, 2003. http://handle.uws.edu.au:8081/1959.7/759.

Повний текст джерела

Анотація:

The aim of this project was to study the nature and relative proportion of the volatile components in the sternal-gland secretions obtained from a wide range of Australian marsupials.The results obtained were then used to investigate the evolution of semiochemicals in Australian marsupials by using the current phylogenetic tree as a template.The initial part of the study was dedicated to the investigation of some of the techniques available for the sampling and analysis of gland secretions. Individuals from 8 families within the Marsupialia and 1 family from the Monotremata were sampled over an 18 month period.The obtained results were then subjected to multivariate statistical analysis followed by cladistic analysis.In several species the secretion composition was found to be affected by the breeding status of individuals for both genders.Many other factors such as animal-age, hierarchical status, diet,and lifestyle were also observed to affect the secretion composition. Finally, cladistic analysis demonstrated the differences in the levels of divergence at the species, familial and ordinal levels and highlighted secretion components that could be used to differentiate between super families, species and even sexual status of individuals.
Master of Science (Hons)

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Zabaras, Regina. "The evolution of semiochemicals in Australian marsupials." Thesis, View thesis View thesis, 2003. http://handle.uws.edu.au:8081/1959.7/759.

Повний текст джерела

Анотація:

The aim of this project was to study the nature and relative proportion of the volatile components in the sternal-gland secretions obtained from a wide range of Australian marsupials.The results obtained were then used to investigate the evolution of semiochemicals in Australian marsupials by using the current phylogenetic tree as a template.The initial part of the study was dedicated to the investigation of some of the techniques available for the sampling and analysis of gland secretions. Individuals from 8 families within the Marsupialia and 1 family from the Monotremata were sampled over an 18 month period.The obtained results were then subjected to multivariate statistical analysis followed by cladistic analysis.In several species the secretion composition was found to be affected by the breeding status of individuals for both genders.Many other factors such as animal-age, hierarchical status, diet,and lifestyle were also observed to affect the secretion composition. Finally, cladistic analysis demonstrated the differences in the levels of divergence at the species, familial and ordinal levels and highlighted secretion components that could be used to differentiate between super families, species and even sexual status of individuals.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Zabaras, Regina. "The evolution of semiochemicals in Australian marsupials." View thesis View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030402.151527/index.html.

Повний текст джерела

Анотація:

Thesis (M.Sc. (Hons.)) -- University of Western Sydney, 2003.
"A thesis presented in partial fulfilment of the requirements for the degree of Master of Science (Honours), College of Science, Technology and the Environment, University of Western Sydney ... January, 2003" Bibliography : leaves 142-150.

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Martin, Meg Louise. "Morpho-functional adaptations to digging in Australian marsupials." Thesis, Martin, Meg Louise (2020) Morpho-functional adaptations to digging in Australian marsupials. PhD thesis, Murdoch University, 2020. https://researchrepository.murdoch.edu.au/id/eprint/58458/.

Повний текст джерела

Анотація:

Digging behaviour has evolved across multiple lineages of Australian marsupials and monotremes, some of which are amongst the most specialised diggers in the world. These animals forage for subterranean food sources, while others dig extensive burrow systems for shelter. The scratch-diggings, in turn, assist in soil turn over, water infiltration, nutrient cycling and dispersal of fungi and seeds, thus playing important roles in ecosystem health. Digging species are capable of generating high out-forces with their forelimbs to excavate soil. As form follows function, forelimb musculoskeletal morphology is expected to be driven by the forces that are imposed by their day-to-day activities, within the constraints imposed by phylogenetic background. In this thesis, I present four studies that quantitatively investigate intra- and inter-specific variation in forelimb adaptations to digging in Australian monotremes and marsupials to examine the link between skeletal morphology and muscle architecture. Representatives of all extant lineages of marsupials (Diprotodontia, Dasyuromorphia, Peramelemorphia, Notoryctemorphia) and monotremes (Monotremata) were used in a correlative study to examine the extent to which functional patterns of limb morphology are influenced by digging behaviour. Study 1 examined ontogenetic development of muscle architecture (muscle mass (mm) and muscle physiological cross-sectional area (PCSA)) in the Quenda (Isoodon fusciventer). This data demonstrated differential development of the muscles acting as main movers of the power-stroke during digging in comparison to recovery-stroke muscles for force production (PCSA) but on the whole suggested mechanical similarity throughout ontogeny in the sample. Study 2 examined the intraspecific relationship between the ontogenetic development of muscle architecture and 2D and 3D measures of bone shape to reveal that the shape of the scapula, humerus and third metacarpal show significant covariation with muscle anatomy. However, the relationship was not well-represented by bone indices. In study 3, the covariation between muscle PCSA and bone shape was quantified across a range of species. Bone shape was significantly different between species of different digging abilities; however, differences were not apparent after phylogenetic correction with the exception of the ulnar and third metacarpal shape. A significant link between muscles PCSA and shape was evident, especially for the scapula, humerus and third metacarpal. Study 4 extended the range of species examined for bone measures to reveal that ulnar shape and bone indices show significant differences between behaviour; this relationship was less evident in the scapula, humerus and third metacarpal. Overall, this collective body of work has quantified the extent to which forelimb muscle architecture and bone shape covary. This thesis also highlights the importance of ontogeny in quantitative studies of muscle architecture, and provides novel models of analysis of post-cranial anatomy. This information furthers the understanding of the complex links between vertebrate form and function. The application of these results will assist in making inferences of the behaviour and ecology of extinct species and the roles they may have played within the Australian ecosystem through time and space.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Donahoe, Shannon. "Comparative pathogenesis of neosporosis and toxoplasmosis in Australian marsupials." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17031.

Повний текст джерела

Анотація:

Clinical and subclinical Neospora caninum and Toxoplasma gondii infections are reported in many animal species globally, including in Australia where little is known about the impact of parasite infection for native fauna. The investigations in this thesis were designed to fill existing knowledge gaps about the significance of neosporosis and toxoplasmosis in Australian marsupials. The fat-tailed dunnart (Sminthopsis crassicaudata) was used as an experimental model to study the immune response and susceptibility to infection of a native marsupial to N. caninum and T. gondii. Neospora-infected dunnarts had significantly more severe clinical and histopathological features of disease, higher tissue parasite burdens, and a less effective Th1 immune response than Toxoplasma-infected dunnarts. These results indicated the marsupial immune response may play a protective role in parasite infections analogous to what has been shown for eutherian models. This study was the first investigation of the marsupial immune response to N. caninum and T. gondii infection. To better understand toxoplasmosis and its significance in Australian wildlife, cases of naturally occurring disease were investigated in terrestrial and marine mammals. Clinicopathological features of disease were described and the causal parasite strains were genotyped. This work suggested that T. gondii may pose a disease threat to common wombats (Vombatus ursinus) and native marine fauna. Atypical and type II-like T. gondii strains accounted for all cases of toxoplasmosis investigated. Finally, to contextualize the possible significance of N. caninum for Australian wildlife, parasite-associated pathology in wildlife was comprehensively reviewed. As a whole, this thesis contributes substantial original knowledge about marsupial host-parasite interactions, pathological consequences of neosporosis and toxoplasmosis in native marsupials, and genetic diversity of T. gondii circulating in Australian wildlife.

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Coldham, Thosaporn Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. "The detection and characterisation of Helicobacter species in Australian marsupials." Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2004. http://handle.unsw.edu.au/1959.4/22370.

Повний текст джерела

Анотація:

This thesis examined the hypotheses that the mucus lining of the gastrointestinal tract (GIT) of Australian marsupials is colonised with large populations of spiral and fusiform shaped bacteria, many of which belong to the genus Helicobacter and that these Helicobacter species are likely be unique. The presence of spiral and fusiform shaped bacteria in the GIT of 8 Australian marsupial species (32 animals in total) was examined using microscopy, culture and Helicobacter genus specific PCR. The marsupials studied included the brushtail possum, ringtail possum, koala, wombat, Eastern grey kangaroo, Tasmanian devil, Eastern quoll and long nosed bandicoot. The spiral and fusiform shaped isolates were characterised and identified using morphological appearance, Helicobacter genus specific PCR and 16S rRNA gene sequence comparisons. The spatial distribution of Helicobacter species in the GIT sections was examined microscopically in silver stained sections of the GIT and using Fluorescent in situ hybridisation (FISH) with a Helicobacter genus specific probe. Spiral and/or fusiform shaped bacteria were detected and/or isolated from all marsupials studied. The prevalence and bacterial load of these organisms was found to differ in each marsupial species. These bacteria were found to belong to 3 different genera (Helicobacter, Campylobacter and Desulfovibrio). Each marsupial species appeared to be colonised with one or more unique Helicobacter species. Comparison of the detection of Helicobacter species in different groups of marsupials (herbivores, omnivores and carnivores) suggests that diet as well as the function and structure of the GIT may have a significant impact on their colonisation. Phylogenetic analysis of the new possum Helicobacters showed that they shared a common ancestor. Comparison of Helicobacter species isolated from different species of marsupial and placental mammals, as well as birds, showed that differences in environmental location i.e. gastric vs lower bowel had a major impact on the position of the Helicobacters on the phylogenetic tree.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

au, M. Banazis@murdoch edu, and Michael Banazis. "Development of tools for surveillance of Coxiella burnetii in domestic ruminants and Australian marsupials and their waste." Murdoch University, 2009. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20090707.114918.

Повний текст джерела

Анотація:

The aim of this study was to develop improved methods to detect viable Coxiella burnetii in wastes from livestock production. The impetus for this work arose because there is a significant risk of infection for humans attributed to contact with waste products from the livestock production industry. This situation is further compounded by the lack of suitable tools to detect viable C. burnetii in these wastes. In addition, effective disinfection strategies for livestock wastes are also required to reduce the risk of infection with C. burnetii for individuals that come into contact with these waste products. A quantitative real-time PCR system (qPCR) with high sensitivity and specificity was developed to detect the C. burnetii in environmental samples associated with domestic ruminants and native Australian marsupials. Different detection chemistries and procedures were evaluated based on their sensitivity, specificity and reproducibility. Overall it was found that the TaqMan PCR targeting the IS1111a locus provided the most sensitive and reproducible test. The Geneworks PowerSoil(tm) DNA isolation kit provided the best compromise between reproducibility and recovery of DNA from livestock wastes. When combined, the IS1111a TaqMan qPCR and Geneworks PowerSoil DNA Extraction Kit provided a test which was capable of detecting as few as two C. burnetii genome equivalents in 0.2g of soil or faeces. Coxiella burnetii has been shown to display extreme resistance to environmental exposure. Therefore, assessment of the viability of the organism in environmental matrices is more useful for risk assessment programs than detection of DNA alone. A quantitative reverse transcriptase PCR was developed that was able to detect viable C. burnetii cells in soil. The sensitivity of the assay was enhanced by heat-treating the soil samples prior to extraction of RNA. The factor most often associated with transfer of C. burnetii to humans is exposure to livestock or their waste. Therefore, decontamination of waste from livestock production industries is a key factor in preventing outbreaks of Q fever. A system was developed to determine the efficacy of various disinfectant treatments against the environmental pathogen C. burnetii. Treatments evaluated included sodium hypochlorite, ozone, ultraviolet light, peracetic acid (PAA), and Virkon S®. Sodium hypochlorite at a concentration of 0.1 mM reduced the infectivity of C. burnetii by over 92% while treatment with the same sodium hypochlorite concentration in wastewater showed significantly reduced efficacy. Despite this reduced potency, sodium hypochlorite is still useful for control of C. burnetii in the liquid waste of animal production. Commercially available ELISA and CFT assays exist for ruminants but there are no immunological tests available for detecting C. burnetii in marsupials even though Australian marsupials are known to be susceptible to C. burnetii. An indirect ELISA for detecting anti-Coxiella antibodies in kangaroos was developed. Paired serum and faecal samples were taken from 379 ruminants from Western Australia and the serum was tested with a commercially available ELISA and the complement fixation test while the faeces was tested using the qPCR developed during this study. Paired serum and faecal samples were taken from 343 kangaroos from WA and were tested with the antibody-ELISA developed during this study and by qPCR. A very low prevalence of anti-Coxiella antibodies was observed in the ruminants sampled and results from immunological tests correlated poorly with qPCR data. The development of an ELISA for use with kangaroo serum was problematic because of the lack of reference sera from animals known to be infected with C. burnetii. Despite this results from the ELISA developed suggested that the apparent seroprevalence in the WA animals surveyed was approximately 34%. Results from testing kangaroo faeces with the qPCR correlated poorly with the results from the antibody-ELISA. These data suggest that kangaroos may be a significant reservoir of C. burnetii in Western Australia and due to cohabitation of kangaroos and domestic ruminants, may provide a link between the wildlife and domestic cycles of C. burnetii.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Banazis, Michael. "Development of tools for surveillance of Coxiella burnetii in domestic ruminants and Australian marsupials and their waste." Thesis, Banazis, Michael (2009) Development of tools for surveillance of Coxiella burnetii in domestic ruminants and Australian marsupials and their waste. PhD thesis, Murdoch University, 2009. https://researchrepository.murdoch.edu.au/id/eprint/718/.

Повний текст джерела

Анотація:

The aim of this study was to develop improved methods to detect viable Coxiella burnetii in wastes from livestock production. The impetus for this work arose because there is a significant risk of infection for humans attributed to contact with waste products from the livestock production industry. This situation is further compounded by the lack of suitable tools to detect viable C. burnetii in these wastes. In addition, effective disinfection strategies for livestock wastes are also required to reduce the risk of infection with C. burnetii for individuals that come into contact with these waste products. A quantitative real-time PCR system (qPCR) with high sensitivity and specificity was developed to detect the C. burnetii in environmental samples associated with domestic ruminants and native Australian marsupials. Different detection chemistries and procedures were evaluated based on their sensitivity, specificity and reproducibility. Overall it was found that the TaqMan PCR targeting the IS1111a locus provided the most sensitive and reproducible test. The Geneworks PowerSoil(tm) DNA isolation kit provided the best compromise between reproducibility and recovery of DNA from livestock wastes. When combined, the IS1111a TaqMan qPCR and Geneworks PowerSoil DNA Extraction Kit provided a test which was capable of detecting as few as two C. burnetii genome equivalents in 0.2g of soil or faeces. Coxiella burnetii has been shown to display extreme resistance to environmental exposure. Therefore, assessment of the viability of the organism in environmental matrices is more useful for risk assessment programs than detection of DNA alone. A quantitative reverse transcriptase PCR was developed that was able to detect viable C. burnetii cells in soil. The sensitivity of the assay was enhanced by heat-treating the soil samples prior to extraction of RNA. The factor most often associated with transfer of C. burnetii to humans is exposure to livestock or their waste. Therefore, decontamination of waste from livestock production industries is a key factor in preventing outbreaks of Q fever. A system was developed to determine the efficacy of various disinfectant treatments against the environmental pathogen C. burnetii. Treatments evaluated included sodium hypochlorite, ozone, ultraviolet light, peracetic acid (PAA), and Virkon S®. Sodium hypochlorite at a concentration of 0.1 mM reduced the infectivity of C. burnetii by over 92% while treatment with the same sodium hypochlorite concentration in wastewater showed significantly reduced efficacy. Despite this reduced potency, sodium hypochlorite is still useful for control of C. burnetii in the liquid waste of animal production. Commercially available ELISA and CFT assays exist for ruminants but there are no immunological tests available for detecting C. burnetii in marsupials even though Australian marsupials are known to be susceptible to C. burnetii. An indirect ELISA for detecting anti-Coxiella antibodies in kangaroos was developed. Paired serum and faecal samples were taken from 379 ruminants from Western Australia and the serum was tested with a commercially available ELISA and the complement fixation test while the faeces was tested using the qPCR developed during this study. Paired serum and faecal samples were taken from 343 kangaroos from WA and were tested with the antibody-ELISA developed during this study and by qPCR. A very low prevalence of anti-Coxiella antibodies was observed in the ruminants sampled and results from immunological tests correlated poorly with qPCR data. The development of an ELISA for use with kangaroo serum was problematic because of the lack of reference sera from animals known to be infected with C. burnetii. Despite this results from the ELISA developed suggested that the apparent seroprevalence in the WA animals surveyed was approximately 34%. Results from testing kangaroo faeces with the qPCR correlated poorly with the results from the antibody-ELISA. These data suggest that kangaroos may be a significant reservoir of C. burnetii in Western Australia and due to cohabitation of kangaroos and domestic ruminants, may provide a link between the wildlife and domestic cycles of C. burnetii.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Banazis, Michael. "Development of tools for surveillance of Coxiella burnetii in domestic ruminants and Australian marsupials and their waste." Banazis, Michael (2009) Development of tools for surveillance of Coxiella burnetii in domestic ruminants and Australian marsupials and their waste. PhD thesis, Murdoch University, 2009. http://researchrepository.murdoch.edu.au/718/.

Повний текст джерела

Анотація:

The aim of this study was to develop improved methods to detect viable Coxiella burnetii in wastes from livestock production. The impetus for this work arose because there is a significant risk of infection for humans attributed to contact with waste products from the livestock production industry. This situation is further compounded by the lack of suitable tools to detect viable C. burnetii in these wastes. In addition, effective disinfection strategies for livestock wastes are also required to reduce the risk of infection with C. burnetii for individuals that come into contact with these waste products. A quantitative real-time PCR system (qPCR) with high sensitivity and specificity was developed to detect the C. burnetii in environmental samples associated with domestic ruminants and native Australian marsupials. Different detection chemistries and procedures were evaluated based on their sensitivity, specificity and reproducibility. Overall it was found that the TaqMan PCR targeting the IS1111a locus provided the most sensitive and reproducible test. The Geneworks PowerSoil(tm) DNA isolation kit provided the best compromise between reproducibility and recovery of DNA from livestock wastes. When combined, the IS1111a TaqMan qPCR and Geneworks PowerSoil DNA Extraction Kit provided a test which was capable of detecting as few as two C. burnetii genome equivalents in 0.2g of soil or faeces. Coxiella burnetii has been shown to display extreme resistance to environmental exposure. Therefore, assessment of the viability of the organism in environmental matrices is more useful for risk assessment programs than detection of DNA alone. A quantitative reverse transcriptase PCR was developed that was able to detect viable C. burnetii cells in soil. The sensitivity of the assay was enhanced by heat-treating the soil samples prior to extraction of RNA. The factor most often associated with transfer of C. burnetii to humans is exposure to livestock or their waste. Therefore, decontamination of waste from livestock production industries is a key factor in preventing outbreaks of Q fever. A system was developed to determine the efficacy of various disinfectant treatments against the environmental pathogen C. burnetii. Treatments evaluated included sodium hypochlorite, ozone, ultraviolet light, peracetic acid (PAA), and Virkon S®. Sodium hypochlorite at a concentration of 0.1 mM reduced the infectivity of C. burnetii by over 92% while treatment with the same sodium hypochlorite concentration in wastewater showed significantly reduced efficacy. Despite this reduced potency, sodium hypochlorite is still useful for control of C. burnetii in the liquid waste of animal production. Commercially available ELISA and CFT assays exist for ruminants but there are no immunological tests available for detecting C. burnetii in marsupials even though Australian marsupials are known to be susceptible to C. burnetii. An indirect ELISA for detecting anti-Coxiella antibodies in kangaroos was developed. Paired serum and faecal samples were taken from 379 ruminants from Western Australia and the serum was tested with a commercially available ELISA and the complement fixation test while the faeces was tested using the qPCR developed during this study. Paired serum and faecal samples were taken from 343 kangaroos from WA and were tested with the antibody-ELISA developed during this study and by qPCR. A very low prevalence of anti-Coxiella antibodies was observed in the ruminants sampled and results from immunological tests correlated poorly with qPCR data. The development of an ELISA for use with kangaroo serum was problematic because of the lack of reference sera from animals known to be infected with C. burnetii. Despite this results from the ELISA developed suggested that the apparent seroprevalence in the WA animals surveyed was approximately 34%. Results from testing kangaroo faeces with the qPCR correlated poorly with the results from the antibody-ELISA. These data suggest that kangaroos may be a significant reservoir of C. burnetii in Western Australia and due to cohabitation of kangaroos and domestic ruminants, may provide a link between the wildlife and domestic cycles of C. burnetii.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Gharibi, Soraya. "Study into selected antimicrobial drugs for koalas (Phascolarctos cinereus), incorporating consideration of koalas’ endogenous plasma and serum antibacterial activity." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18012.

Повний текст джерела

Анотація:

Pharmacokinetic studies of some drugs in koalas argue that traditional ad-hoc dosage extrapolation from dogs and cats to koalas is inappropriate. This research describes plasma concentration changes of cefovecin and amoxicillin in koalas. Posaconazole was also investigated as its broad-spectrum antifungal activity might be efficacious against cryptococcosis in koalas. HPLC methods to determine plasma concentrations of these antimicrobials were developed and validated. Posaconazole was administered at 3 mg/kg to two koalas i.v. and 6 mg/kg to six koalas p.o. Posaconazole is predicted to be efficacious for cryptococcosis treatment in koalas. An in-vitro study to determine cefovecin binding to plasma proteins of koalas and some Australian marsupials demonstrated the proportion of binding between 12 to 40 %, suggesting the elimination half-life of cefovecin in these species is likely to be shorter than those in dogs and cats. Cefovecin was administered as a single bolus (8 mg/kg) to six koalas s.c. Cefovecin plasma concentrations at all time points (0 to 96 h) in all animals were below 1 μg/mL, indicating cefovecin has a short duration of action in koalas. Amoxicillin was administered to six koalas at 10 mg/kg s.c. Low concentrations of amoxicillin were detected; however, drug instability might have contributed towards these findings. Bioassays were undertaken to confirm amoxicillin and cefovecin HPLC results. The bioassays demonstrated variable plasma antibacterial activities at t = 0 h (before koalas were medicated). Consequently, endogenous antibacterial activities of koala plasma and serum to inhibit E. coli and S. aureus were evaluated. Koala blood matrices demonstrated significant variations in inhibiting both pathogens’ growth compared to other species studied. Reasons for such variations were unclear but opened a new area for investigating koalas’ endogenous antimicrobial activity and how it might protect this ‘vulnerable’ species from infectious diseases.

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Austen, Jill. "Characterisation of native Trypanosomes and other protozoans in the Australian marsupials the Quokka (Setonix brachyurus) and the Gilbert's Potoroo (Potorus gilbertii)." Thesis, Austen, Jill ORCID: 0000-0002-1826-1634 (2015) Characterisation of native Trypanosomes and other protozoans in the Australian marsupials the Quokka (Setonix brachyurus) and the Gilbert's Potoroo (Potorus gilbertii). PhD thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/31139/.

Повний текст джерела

Анотація:

Trypanosomes are blood-borne parasites that can cause severe disease in both humans and animals, resulting in very large economic losses worldwide. In contrast to the wealth of information on pathogenic species such as Trypanosoma cruzi and Trypanosoma brucei, little is known of the pathogenicity, prevalence and life-cycles of trypanosomes in native Australian mammals. The aim of this thesis was to characterise trypanosomes and other protozoans from the critically endangered Gilbert’s potoroo (Potorous gilbertii) and the quokka (Setonix brachyurus) from Western Australia using morphological and molecular analysis. A novel Trypanosoma species, Trypanosoma copemani was identified in Gilbert’s potoroos and quokkas using molecular and morphological analysis. Further molecular characterisation of T. copemani in quokkas at both the 18S rRNA and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) loci identified multiple T. copemani genotypes revealing that the parasite is genetically variable. Given the phylogenetic grouping of T. copemani as a stercorarian (requiring faecal transmission by vector), the fact that ticks are common ectoparasites of Gilbert’s potoroos and quokkas and the previous identification of trypanosomes in ticks, ticks were examined as potential vectors of T. copemani. Motile trypanosomes were detected in both the haemolymph and midgut sections of Ixodes australiensis ticks removed from quokkas and Gilbert’s potoroos and stained trypanosomes were detected within a faecal smear. Morphologically, the tick trypanosomes resembled in vitro forms of T. copemani, representing epimastigotes and slender trypomastigote stages, with dividing stages detected within the midgut region. Molecular analysis of the tick isolates, showed 100% sequence identity to T. copemani at the 18S rRNA locus, suggesting that the tick is a putative vector for T. copemani. Investigation of the life-cycle stages of native Australian trypanosomes using microscopy and in vitro culture of blood from quokkas and Gilbert’s potoroos revealed that native Australian trypanosomes are highly polymorphic, with three different trypomastigote blood stream forms detected within blood films, resembling slender, medium and broad stages. In addition, promastigote, sphaeromastigote and amastigote stages were observed directly within blood films and this is the first report of these stages in the circulatory system of Australian marsupials. Three novel trypanosome life-cycle forms representing an oval form, an extremely thin form and an adherent form were also identified both in vitro and in vivo, while a novel tiny form and a novel circular form were only detected in culture. Trypanosoma vegrandis was also detected for the first time in one quokka isolate (Q1340) and confirmed using species-specific primers. As tourists and quokkas on Rottnest Island have a close relationship, the zoonotic potential of T. copemani was investigated by determining the relative susceptibility of T. copemani to human serum using the blood incubation infectivity test. Trypanosoma copemani was observed by microscopy in all human blood cultures from day 5 to day 14 post inoculation. The mechanism for normal human serum resistance in T. copemani is not known. The results of this thesis show that at least one native Australian trypanosome species may have the potential to infect humans. In addition to blood, quokka faecal samples were also collected to investigate the prevalence of Eimeria by PCR screening of faecal samples from three quokka populations, Two Peoples Bay, Bald Island and Rottnest Island, respectively. The PCR prevalence of Eimeria was 62.5%, 85.0% and 78.3% for these three locations respectively. Two Eimeria species were identified based on morphometric analysis from sporulated oocysts, Eimeria quokka and Eimeria setonicis, with the majority of quokkas co-infected with both species. Singular infections, however, were identified in a few individuals allowing molecular analysis to be performed using both the 18S rRNA and cytochrome c oxidase subunit 1 genes. Phylogenetic analysis grouped E. quokka and E. setonicis within the Eimeria marsupial clade. This study is the first one to characterise E. quokka and E. setonicis by molecular analyses, enabling more extensive resolution of evolutionary relationships among marsupial-derived Eimeria species. Overall this study has characterised the novel T. copemani in both the quokka and the Gilbert’s potoroo and has shown T. copemani to be both morphologically and genetically variable. This is a stercorarian trypanosome, transmitted through vector faecal contamination and may potentially be infectious to humans. The findings of this thesis highlight the complexity of Australian trypanosomes and provide insights into the prevalence, potential pathogenicity and human infectivity of this novel parasite. Further research is required to assess the role of trypanosome infection on marsupial population dynamics and the implications for management and conservation.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Botero, Gomez Adriana. "Genotypic and phenotypic diversity of trypanosomes infecting Australian marsupials and their association with the population decline of the brush-tailed bettong or woylie (Bettongia penicillata)." Thesis, Botero Gomez, Adriana (2014) Genotypic and phenotypic diversity of trypanosomes infecting Australian marsupials and their association with the population decline of the brush-tailed bettong or woylie (Bettongia penicillata). PhD thesis, Murdoch University, 2014. https://researchrepository.murdoch.edu.au/id/eprint/24863/.

Повний текст джерела

Анотація:

Trypanosomes are flagellated blood parasites that are capable of infecting virtually all classes of vertebrates. They range from non-pathogenic species to those that are highly pathogenic and are the causative agents of many diseases of medical and veterinary importance. While much is known of their impact on human health or economic development, a great deal less is known of those associated with wildlife. Within Australia, trypanosomes have been found naturally infecting a wide range of native marsupials, most of which are considered threatened or endangered. However, their research has largely been confined to the description of trypanosome morphology in blood, and a complete lack of information regarding their life cycle, virulence, and pathogenicity is evident. This study therefore, aimed to investigate the genotypic and phenotypic diversity of Trypanosoma spp. infecting Western Australia marsupials and to determine their potential pathogenicity with particular emphasis in the critically endangered marsupial, the woylie (Bettongia penicillata). The genotypic characterisation was achieved using a combination of sequencing and phylogenetic analysis of trypanosomes in the blood and tissues of nine different marsupial species, as well as the sequencing of partial fragments of the minicircles of the kinetoplast DNA of trypanosomes isolated in culture. The phenotypic characterisation involved a combination of histology, microscopy techniques, and in vitro experiments of cell infection and drug susceptibility. Results revealed that eight different genotypes belonging to three different Trypanosoma species: T. copemani, T. vegrandis, and T. sp H25 were found infecting woylies (Bettongia penicillata), quendas (Isoodon obesulus), quokkas (Setonix brachyurus), tammar wallabies (Macropus eugenii), banded hare wallabies (Lagostrophus fasciatus), boodies (Bettongia lesueur), Chuditches (Dasyurus geoffroii), common brush tailed possums (Trichosurus vulpecula), and western grey kangaroos (Macropus fuliginosus). However, the woylie was the only marsupial species where single individuals and single tissues were co-infected with genotypes belonging to the three different Trypanosoma species. Furthermore, T. copemani G2, the predominant trypanosome in the declining population of woylies, was shown to be able to infect tissue cells and generate a strong immune response characterised by tissue degeneration and necrosis in vital organs, suggesting an association between these infections and the decline of the woylie. Comparative analysis between T. copemani G2 and the pathogenic T. cruzi showed not only similarities in their capacity to infect tissue cells, but also in drug susceptibility and kinetoplast DNA organisation. In summary, this study not only contributes valuable information towards directing management decisions for endangered species where trypanosomes are known to be present at high prevalence levels, but also provides new knowledge about the evolutionary biology and relationships that Australian trypanosomes have with the exotic and pathogenic T. cruzi.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Fazenda, Inês Isabel Paulo. "Molecular and morphological characterization of the genus globocephaloides from macropodid marsupials in Australia." Bachelor's thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2009. http://hdl.handle.net/10400.5/1302.

Повний текст джерела

Анотація:

Dissertação de Mestrado Integrado em Medicina Veterinária
The genus Globocephaloides (Nematoda: Trichostrongyloidea) is a pathogenic group of parasitic nematodes present in the duodenum of kangaroos and wallabies (Marsupialia: Macropodidae) in Australia. Globocephaloides species (G. trifidospicularis, G. macropodis and G. affinis) have been poorly studied and thus, there are significant controversies regarding their systematics and population structures. In the present study, single-strand conformation polymorphism (SSCP) and targeted sequencing of the internal transcribed spacers (ITS) of nuclear ribosomal DNA, were used to assess the genetic variation within and among Globocephaloides populations and individuals, from different host species and geographical origins. No or minor (0.2%) variation was detected among individuals of G. trifidospicularis and G. affinis. However, within G. macropodis populations there was a consistent heterogeneity in the ITS sequences (5.2 - 7.1%) between worms derived from two different host species (Macropus agilis and M. dorsalis). Under light microscopy, these two G. macropodis genotypes differed by the length, arrangement and tip of the spicules, and by pattern of the bursal rays. Thus, they were considered to represent sibling species. The molecular and morphological evidence culminated with the erection of a new species, namely G. wallabiae, and provided further insights into the host affiliation and geographical ranges of Globocephaloides spp.: G. wallabiae occurs mainly in M. dorsalis (north/east), G. macropodis in M. agilis and Petrogale persephone (north), G. affinis in M. dorsalis (north-east), and G. trifidospicularis in various Macropus species (south). Moreover, in the present study, the phylogenetic analyses between the genus Globocephaloides and other trichostrongyloid genera, using divergent domains of the 28S rRNA genes, gave evidence for the exclusion of the genus Globocephaloides from the Herpetostrongylidae, with the suggestion of a new family, namely „Globocephaloididae‟, within the Heligmosomoidea.
RESUMO - CARACTERIZAÇÃO MOLECULAR E MORFOLÓGICA DO GÉNERO GLOBOCEPHALOIDES EM MARSUPIAIS MACROPODÍDEOS NA AUSTRÁLIA - O género Globocephaloides (Nematoda: Trichostrongyloidea) é um importante grupo de nemátodes patogénicos presente no duodeno de cangurus e wallabies (Marsupialia: Macropodidae) na Austrália. O estudo das espécies de Globocephaloides (G. trifidospicularis, G. macropodis e G. affinis) tem sido limitado, e por isso, existem numerosas controvérsias em relação à sua sistemática e às suas estruturas populacionais. No presente estudo, as técnicas de análise de ácidos nucleicos, „single-strand conformation polymorphism‟ (SSCP) e sequenciação-alvo da região ITS („internal transcribed spacers‟) do DNA ribossomal foram usadas com o objectivo de analisar a variação genética entre indivíduos e populações de Globocephaloides provenientes de diferentes hospedeiros e áreas geográficas. Em ambas as espécies G. trifidospicularis e G. affinis pouca ou nenhuma variação foi encontrada (0.2%). Contudo, nas populações de G. macropodis foi detectada uma consistente heterogeneidade nas sequências ITS (5.2 - 7.1%) entre espécimes provenientes de dois hospedeiros distintos (Macropus agilis e M. dorsalis). Recorrendo à microscopia óptica verificou-se que os dois genótipos de G. macropodis diferiam no comprimento, conformação e ponta das espículas, assim como, no padrão dos raios da bolsa copuladora. Como tal, foi considerado que os dois genótipos representavam duas espécies congéneres. Os resultados da biologia molecular e do estudo morfológico determinaram o reconhecimento de uma nova espécie denominada G. wallabiae e, além disso, forneceram dados sobre a especificidade de hospedeiros e distribuição geográfica do género Globocephaloides. G. wallabiae ocorre principalmente no hospedeiro M. dorsalis (norte/este), G. macropodis no M. agilis e Petrogale persephone (norte), G. affinis no M. dorsalis (nordeste) e G. trifidospicularis em várias espécies do género Macropus (sul). Adicionalmente, a análise das relações filogenéticas entre o género Globocephaloides e outros tricostrongilídeos, empregando os domínios do gene 28S rRNA, deu provas para a exclusão do género Globocephaloides da família Herpetostrongylidae, com a sugestão de uma nova família, denominada „Globocephalidae‟, inserida na superfamília Heligmosomoidea.
Financial support provided to the supervisors for the present study was from bodies including the Australian Research Council (ARC) [to Robin B. Gasser] and Australian Biological Resources Study (ABRS) [to Ian Beveridge]

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Mutton, Thomas Y. "Evolutionary biology of the Australian carnivorous marsupial genus Antechinus." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/104321/6/Thomas_Mutton_Thesis.pdf.

Повний текст джерела

Анотація:

Antechinus is an Australian genus of small carnivorous marsupials. Since 2012, the number of described species in the genus has increased by 50% from ten to fifteen. The systematic relationships of these new species and others in the genus have not been well resolved and a broad phylogeographic study of the genus is lacking. Moreover, little ecological information is known about these new species. Therefore, the present thesis examined the evolutionary biology of Antechinus in two complimentary components. The first component aimed to resolve the systematics and phylogeography of the genus Antechinus. The second component, at a finer spatiotemporal scale, aimed to improve understanding of the autecology, habitat use and risk of extinction within the group, with a focus on the recently named buff-footed antechinus, A. mysticus and a partially sympatric congener, A. subtropicus.

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Wormington, Kevin Ray. "The habitat requirements of arboreal marsupials in dry sclerophyll forests of south-east Queensland, Australia /." St. Lucia, Qld, 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17558.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Miller, Emily Jane Biological Earth &amp Environmental Sciences Faculty of Science UNSW. "Conservation genetics and reproduction in three Australian marsupial species." Publisher:University of New South Wales. Biological, Earth & Environmental Sciences, 2008. http://handle.unsw.edu.au/1959.4/42779.

Повний текст джерела

Анотація:

Many Australian marsupial species require active population management to ensure their survival in the wild. Such management should be based on a sound understanding of species biology. This thesis explores how knowledge of reproduction and genetics can be applied to the management of three Australian marsupial species faced with contrasting management scenarios. The ??vulnerable?? greater bilby is the sole remaining desert bandicoot in Australia. They are a secretive, solitary species whose mating system is unclear. This research examined temporal changes in genetic diversity within two captive breeding programs utilising different management strategies. Using seven microsatellite loci, this study found the regular translocation of new individuals into the population maintained genetic diversity. Parentage analysis revealed the bilby to have a promiscious mating system. Sires and non-sires could not be distinguished by morphological traits. The tammar wallaby is a polygynous, solitary species that is threatened on mainland Australia, but overabundant on some offshore islands. The population genetics of tammars from the Abrolhos Islands in Western Australia were examined using nine autosomal and four Y-linked microsatellite loci, and mitochondrial DNA. There was a relationship between island size, population size and genetic diversity. The Abrolhos populations have significantly lower genetic diversity and are more inbred than mainland tammars and all sampled populations were significantly differentiated. The Abrolhos and mainland populations should be treated as separate Management Units. The eastern grey kangaroo is a gregarious, polygynous species that is often locally overabundant. To determine traits influencing male reproductive success, behavioural, morphological, physiological and genetic data were examined and showed dominance status, body size and testosterone concentrations were important factors. Sires were also significantly more heterozygous and genetically dissimilar to females, than non-sires. As body condition influences individual fitness, and management decisions; five body condition indices (BCI) calculated from morphological data were validated using serum biochemistry and haematology in two kangaroo populations with contrasting body condition. Blood parameters were found to be more reliable indicators of condition, questioning the credibility of BCIs currently used in management. These studies demonstrate the importance of reproductive and genetic data in assisting wildlife management, regardless of a species conservation status.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Brandies, Parice Amber. "Conserving Australia's iconic marsupials; one genome at a time." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/26787.

Повний текст джерела

Анотація:

In the midst of a global sixth mass extinction event, conservation initiatives are now more crucial than ever. Australia houses the most diverse range of marsupial species in the world; however, the number that are threatened is growing every year. Genetic management of threatened populations is vital in species recovery, yet incorporation of genetic data in conservation management is currently limited. International and national genome sequencing consortia are currently producing reference genomes for a large variety of species, though there is currently a gap between the creation of these genomic resources and their downstream applications, particularly in conservation contexts. One of the major drivers of this gap is due to the bioinformatic expertise and resources that are required to analyse genomic datasets and to translate the findings into conservation management. This PhD employs a variety of bioinformatic and sequencing approaches to develop genomic resources for threatened Australian Marsupials and demonstrates how these resources can be used as a tool to assist species conservation. The value of genomic data for conservation is demonstrated for a range of species under varying scenarios including: i) using existing genomic datasets for the endangered Tasmanian devil to answer new conservation questions relating to reproduction, ii) creating a reference genome for the common brown antechinus, to act as a model species for its threatened congeneric counterparts and iii) generating and uniting a suite of genomic resources to assist in the management of the vulnerable greater bilby. In addition, ten simple rules for getting started with command-line bioinformatics are presented to facilitate the use of genomic data in wildlife conservation. Bridging the research-implementation gap is essential for harnessing the power of genomic resources for the conservation of threatened species. The findings from this PhD provide crucial steps into bridging this gap.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Walia, Charanjiv Singh. "Development of a method for the identification of novel viruses in marsupials with the polymerase chain reaction (PCR)." Thesis, View thesis View thesis View thesis, 2002. http://handle.uws.edu.au:8081/1959.7/815.

Повний текст джерела

Анотація:

Four main types of viruses capable of causing systemic and gastrointestinal infections, namely Coronavirus, Rotavirus, Parvovirus or Morbillivirus (Tennant et al, 1991) have been investigated in marsupials. A pilot study to develop and optimise the methodology was undertaken using Canine Coronavirus and the study was then extended to marsupials and other target viruses.In the marsupial portion of the study, a fragment of the correct size for the amplification of pol gene, 409 bp, was obtained from two different faecal samples from tammar wallaby (from Macquarie Fauna Park) and one western grey kangaroo (from Taronga Zoo). The results from tests are studied and compared. It is suggested that future further investigation should be directed at: 1/. Applying the protocols in this body of work to the testing of faecal samples from animals that have been diagnosed as positive with other diagnostic protocols. 2/. Examining more faecal samples from animals that present with active diarrhoea

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Hillman, Alison. "Urbanisation and small marsupials in the greater Perth region, Western Australia." Thesis, Hillman, Alison (2016) Urbanisation and small marsupials in the greater Perth region, Western Australia. PhD thesis, Murdoch University, 2016. https://researchrepository.murdoch.edu.au/id/eprint/33177/.

Повний текст джерела

Анотація:

Background Quenda (Isoodon obesulus) and brushtail possums (Trichosurus vulpecula) remain in many areas of Perth, Western Australia, despite urbanisation. This thesis investigated the impacts of urbanisation on the parasitic infections, morphometrics and reproductive fitness of these marsupials. Parasite screening particularly investigated the presence of parasites that quenda and possums may be acquiring from humans and pets in urbanised environments. Methods This cross sectional study targeted free-ranging quenda and brushtail possums in Perth. Trapping was undertaken on 29 bushland sites and 35 urbanised sites. Trapped marsupials were sampled for gastrointestinal and macroscopic ecto- parasites and Toxoplasma gondii antibodies, and morphometrics were measured. Statistical analyses included linear and logistic regression, Kulldorff’s spatial scan statistic and analysis of similarities in parasite communities. Results 287 quenda and 33 brushtail possums were sampled across 55 sites. Parasitic infections were common in Perth quenda, and less so in brushtail possums. Twelve parasite taxa were identified infecting these host species for the first time. In quenda, some differences in parasite prevalences, odds of infection, intensities of infection, and parasite communities, were observed in quenda trapped in urbanised environments compared to bushland. In quenda, Giardia spp. infection was common, and typically the non-zoonotic G. peramelis. Analyses suggest that the primary influence on the distribution of Giardia spp. infection in quenda is population density. Quenda trapped in urbanised environments were heavier on average than quenda trapped in bushland, in the absence of convincing evidence of a difference in skeletal morphometrics. Bushland adult female quenda had increased odds of having an active pouch than those in urbanised environments. Conclusions Quenda and brushtail possums in Perth are not commonly infected with gastrointestinal and macroscopic ecto- parasites of humans and domestic animal origin. Quenda in urbanised environments have a tendency towards obesity. Urbanised environments may negatively impact fecundity of female quenda.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

MacDonald, Anna Jayne, and n/a. "Sex chromosome microsatellite markers from an Australian marsupial: development, application and evolution." University of Canberra. n/a, 2008. http://erl.canberra.edu.au./public/adt-AUC20081217.122146.

Повний текст джерела

Анотація:

Microsatellites are simple repetitive DNA sequences that are used as genetic markers throughout the biological sciences. The high levels of variation observed at microsatellite loci contribute to their utility in studies at the population and individual levels. This variation is a consequence of mutations that change the length of microsatellite repeat tracts. Current understanding suggests that most mutations are caused by polymerase slippage during DNA replication and lead to changes of a single repeat unit in length, but some changes involving multiple repeats can also occur. Despite this simplistic overview, there is evidence for considerable heterogeneity in mutation processes between species, loci and alleles. Such complex patterns suggest that other mechanisms, including those associated with DNA recombination, are also involved in the generation of microsatellite mutations. Understanding which mutational mechanisms are responsible for variation at microsatellite markers is essential to enable accurate data interpretation in genotyping projects, as many commonly used statistics assume specific mutation models. I developed microsatellite markers specific to the X and Y chromosomes and an autosome in the tammar wallaby, Macropus eugenii, and investigated their evolutionary properties using two approaches: indirectly, as inferred from population data, and directly, from observation of mutation events. First, I found that allelic richness increased with repeat length and that two popular mutation models, the stepwise mutation model and the infinite allele model, were poor at predicting the number of alleles per locus, particularly when gene diversity was high. These results suggest that neither model can account for all mutations at tammar wallaby microsatellites and hint at the involvement of more complex mechanisms than replication slippage. I also determined levels of variation at each locus in two tammar wallaby populations. I found that allelic richness was highest for chromosome 2, intermediate for the X chromosome and lowest for the Y chromosome in both populations. Thus, allelic richness varied between chromosomes in the manner predicted by their relative exposure to recombination, although these results may also be explained by the relative effective population sizes of the chromosomes studied. Second, I used small-pool PCR from sperm DNA to observe de novo mutation events at three of the most polymorphic autosomal markers. To determine the reliability of my observations I developed and applied strict criteria for scoring alleles and mutations at microsatellite loci. I observed mutations at all three markers, with rate variation between loci. Single step mutations could not be distinguished because of the limitations of the approach, but 24 multi-step mutations, involving changes of up to 35 repeat units, were recorded. Many of these mutations involved changes that could not be explained by the gain or loss of whole repeat units. These results imply that a large number of mutations at tammar wallaby microsatellites are caused by mechanisms other than replication slippage and are consistent with a role for recombination in the mutation process. Taken as a whole, my results provide evidence for complex mutation processes at tammar wallaby microsatellites. I conclude that careful characterisation of microsatellite mutation properties should be conducted on a case-by-case basis to determine the most appropriate mutation models and analysis tools for each locus. In addition, my work has provided a set of chromosome-specific markers for use in macropod genetic studies, which includes the first marsupial Y chromosome microsatellites. Sex chromosome microsatellites open a new range of possibilities for population studies, as they provide opportunities to investigate gene flow in a male context, to complement data from autosomal and maternally-inherited mitochondrial markers.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Walia, Charanjiv Singh, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "Development of a method for the identification of novel viruses in marsupials with the polymerase chain reaction (PCR)." THESIS_CSTE_SFH_Walia_C.xml, 2002. http://handle.uws.edu.au:8081/1959.7/815.

Повний текст джерела

Анотація:

Four main types of viruses capable of causing systemic and gastrointestinal infections, namely Coronavirus, Rotavirus, Parvovirus or Morbillivirus (Tennant et al, 1991) have been investigated in marsupials. A pilot study to develop and optimise the methodology was undertaken using Canine Coronavirus and the study was then extended to marsupials and other target viruses.In the marsupial portion of the study, a fragment of the correct size for the amplification of pol gene, 409 bp, was obtained from two different faecal samples from tammar wallaby (from Macquarie Fauna Park) and one western grey kangaroo (from Taronga Zoo). The results from tests are studied and compared. It is suggested that future further investigation should be directed at: 1/. Applying the protocols in this body of work to the testing of faecal samples from animals that have been diagnosed as positive with other diagnostic protocols. 2/. Examining more faecal samples from animals that present with active diarrhoea
Master of Science (Hons)

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Nedin, Christopher. "The nature of the Precambrian-Cambrian transition in the northern Flinders Ranges, South Australia ; The dietary niche of the extinct Australian marsupial lion Thylacoleo carnifex Owen /." Title page, abstract and contents only, 1990. http://web4.library.adelaide.edu.au/theses/09SB/09sbn371.pdf.

Повний текст джерела

Анотація:

Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1991?
Two col. maps in pocket. National grid reference: Coply SH54-9 1:250 000. Includes bibliographical references.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

uk, rebecca vaughan@ioz ac, and Rebecca Jane Vaughan. "Health and disease status of Australia's most critically endangered mammal the Gilbert's potoroo(Potorous gilbertii)." Murdoch University, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20100423.124817.

Повний текст джерела

Анотація:

The Gilberts potoroo (Potorous gilbertii) is a small marsupial endemic to the Two Peoples Bay Nature Reserve in the south-west of Western Australia. The Gilberts potoroo is classified as Australias most critically endangered mammal (IUCN 2006) with an estimated population of only 35 individuals. This thesis examines the health and disease status of the Gilberts potoroo, presenting a strong case for the relatively new concept of disease as a potential threatening factor and modifier of population decline. Specific diseases, including Cryptococcus, ectoparasitism, endoparasitism, haemoparasitism, Toxoplasma and a novel Treponema organism are extensively studied. An assessment of the clinical significance of these diseases is made, and management strategies are recommended to minimise the impact of these diseases on both the wild and captive population. The novel Treponema organism which clinically presents with tenacious, green discharge and an associated balanoposthitis in males is molecularly characterized. Epidemiological studies show the effects of this agent on reproductive function and a penicillin-based treatment regime is trialled in the analogous long-nosed potoroo (Potorous tridactylus) with a recommendation to then trial this treatment regime in the critically endangered Gilberts potoroo. Standard haematological and urinalysis findings are tabulated to form reference ranges for this species. A treatment regime for Cryptococcus in the analogous long-nosed potoroo is reported and parasitological findings, including the identification of a novel tick species are discussed. This thesis addresses key health issues, which have subsequently been incorporated into the Recovery Plan of the Gilberts potoroo. A document encompassing multiple disciplines and expertise to support the recovery of this critically endangered marsupial in its current environment. In addition, this thesis outlines a recommended health monitoring and treatment protocol for future translocation procedures and provides a working example of the emerging importance of health monitoring in threatened species recovery programs.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Taylor, Brendan Dominic. "Use and effectiveness of engineered road crossing-structures for wildlife in eastern Australia." Thesis, Griffith University, 2010. http://hdl.handle.net/10072/365203.

Повний текст джерела

Анотація:

Roads are primary agents of habitat fragmentation and transform landscapes on a global scale. Roads remove habitat and create barriers or filters to the movement of many wildlife species. Moreover, roads disrupt population processes by breaking up continuous populations into smaller, isolated subpopulations or metapopulations, which can suffer genetic drift and become more vulnerable to stochastic processes. Consequently, understanding and mitigating the impact of roads on wildlife has attracted increasing international interest in recent decades. Foremost in efforts to re-connect wildlife populations severed by roads has been the installation of crossing-structures. These are engineered structures designed to provide the opportunity for animals to safely cross either over the road (e.g. land-bridges, rope or wooden canopy-bridges) or under the road (e.g. underpasses, culverts, ecopipes). Crossing-structures enhance the permeability of roads to animal movement thereby improving the ‘functional connectivity’ of the surrounding landscape, or the degree to which the inter-fragment landscape (matrix) facilitates movement. Crossing-structures have thus become a common feature of new road projects in developed countries. Research into the efficacy of crossing-structures is very much in its infancy and has largely focused on assessing whether structures are being used by different wildlife species. As a consequence, we know very little about higher order questions pertaining to population processes, particularly whether the viability of local populations is enhanced by the deployment of crossing-structures. Furthermore, the deployment of crossing-structures has largely focused on terrestrial vertebrates and scant attention has been directed at mitigating road impacts on arboreal mammals, particularly gliding mammals (gliders). This thesis endeavours to address some of these information gaps by presenting the results of a number of investigations into wildlife use of road crossing-structures located in subtropical, eastern Australia. The topics of investigation include: i) glider use of wooden poles on a road land-bridge; ii) home-ranges of gliders residing near road crossing-structures; iii) modelling the effect of connecting habitat patches across road-gaps on glider metapopulation viability; and, vi) determining the effect of road widening on bandicoot use of highway underpasses. They represent the first studies of their kind to investigate such topics. The Australian squirrel glider Petaurus norfolcensis (Marsupialia: Diprotodontia) is a gliding marsupial distributed along the eastern seaboard of Australia. It is listed as threatened in the southern part of its geographic range due to habitat fragmentation. I investigated whether 7-m high wooden poles installed on a land-bridge could enable squirrel gliders to cross a road canopy-gap at two locations in Brisbane, the capital city of Queensland. This represented the first attempt in the world to facilitate road crossing by a gliding mammal in this way. At one location no road crossing was revealed from trapping over a 3-year period. Radio-tracking over 8 months revealed 3 occasions when animals whose home-ranges were aligned along the road had crossed the road. Hair-sampling devices revealed use of the poles at one location during 15 of 20 sampling sessions over a 3-year period, and at the second location during 6 of 6 sampling sessions over a 6-month period. Detection of hair on all poles during some sessions at both locations suggests complete crossings could occur. These observations suggest that wooden poles can be used to facilitate road-crossing by gliding mammals. Obtaining information on the use of novel road-crossing technologies such as gliding poles is a necessary first step to understanding their efficacy. However, the ultimate test of a crossing-structure’s effectiveness is in establishing to what extent has it alleviated the barrier effect of the road and prevented the extirpation of local populations. Accordingly, I utilised the population modelling program VORTEX to assess the viability of a metapopulation of squirrel gliders and Australia’s largest gliding marsupial, the greater glider (Petauroides volans), occurring in forest remnants in the fastest urbanising region of Australia. Population studies were conducted over two years within two of these forest remnants (one small, one large) connected across a major road by a land-bridge with gliding poles and rope canopy-bridges. Whereas I obtained direct evidence of squirrel glider use of the land-bridge poles, it is currently unknown whether greater gliders will use the crossing structures but available tree height and spacing do not allow a glide crossing and fences with metal flashing prevent access to the road by terrestrial and arboreal mammals. My modelling revealed that even a relatively low rate of dispersal facilitated by these structures would substantially reduce the probability of extirpation of the smaller subpopulation for both glider species. This rate of dispersal is plausible given the small distance involved (~50 m). The inclusion of wildfire as a catastrophe in my model suggests that these two remnants may encounter an undesirable level of extinction risk. This can be reduced to an acceptable level by including inter-patch movement via dispersal among other forest remnants. However, this requires connection to a very large remnant 8 km away, through a set of smaller remnants that straddle two motorways. These motorways create discontinuities in forest cover that are beyond the gliding ability of both these species and will require the deployment of crossing-structures to allow inter-patch movement. Whereas our knowledge of wildlife use of road crossing-structures has grown considerably in recent years, little is known about the effect that road widening may have on patterns of use by target fauna. To address this, I investigated the effect that duplicating a highway had on bandicoot (Marsupialia: Peramelemorphia) use of underpasses at Brunswick Heads in north east New South Wales (NSW). This study represented one of the first of its kind in Australia and spanned the period of pre and post-construction over an eight year period. Evidence from trapping data showed that individuals of the two bandicoot species present at the study site (i.e. Isoodon macrourus and Perameles nasuta) incorporated both sides of the road corridor into their home ranges and that the majority of movements were likely associated with foraging. The trapping data also demonstrated spatial overlap between and within sexes and congeners suggesting that underpasses were functionally available to resident animals and were each being used by multiple individuals. Despite this, gaining clear insights on the effect that road-widening had on underpass use by bandicoots was confounded by drought, loss of high quality habitat, a decline in bandicoot abundance, the presence of foxes and different design characteristics of new underpasses. Further surveys are required at Brunswick Heads to elucidate this issue. The results of my investigations on bandicoot and glider use of road crossing-structures provide strong support for the need to manage road impacts on wildlife at multiple scales. At the patch or site-level, a number of enhancements are required to improve the functionality of the investigated crossing-structures and to make the study sites more amenable to the target species. At the landscape-level, management needs to focus on improving functional connectivity in the surrounding landscape to strengthen the viability of local metapopulations. This will require the combination of habitat restoration works, wildfire control and the deployment of crossing structures where large roads and motorways breach forest cover. In the case of gliders, the deployment of crossing-structures can be achieved rapidly and cost-effectively by installing gliding poles along motorway edges and in median strips at locations where forest cover is breached. Future research at these study sites needs to continue for much longer periods (i.e. 5-10 years) and incorporate genetic techniques. This will assist in improving our understanding of the isolation effects of road barriers and whether or not gene flow is restored by the installation of crossing-structures. This should be routinely combined with viability assessments (e.g. PVA) to determine how populations are affected by roads and whether they might benefit from crossing structures. Research is also required to provide insights to dispersal behaviour, particularly for gliders, and the likely use of road-crossing structures. Loss of habitat and habitat connections is continuing in my study landscapes and this is likely to have dire consequences for wildlife if land managers are unable to retain appropriate habitat cover with corridors and install effective wildlife road crossing-structures where large roads bisect wildlife habitat.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Saffer, V. M. "A comparison of foodplant utilization by nectar-feeding marsupials and birds in the Fitzgerald River National Park, Western Australia." Thesis, Saffer, V.M. (1998) A comparison of foodplant utilization by nectar-feeding marsupials and birds in the Fitzgerald River National Park, Western Australia. PhD thesis, Murdoch University, 1998. https://researchrepository.murdoch.edu.au/id/eprint/51799/.

Повний текст джерела

Анотація:

In heathlands at the western end of the Fitzgerald River National Park, Western Australia, Honey Possums Tarsipes rostratus were the most abundant mammal and meliphagid honeyeaters the most abundant birds. These heathlands contain many plant species in the families Proteaceae and Myrtaceae, whose protracted and asynchronous, yet overlapping, patterns of flowering result in nectar and pollen available all year. This continual food resource supports vertebrate populations that are predominantly nectarivorous. This thesis examines inter-relationships between nectar-feeding mammals and birds, and floral assemblages that supported them, at the western end of the Park between June 1994 and March 1997. The characteristics of the flowers visited most often were assessed in relation to the different pollination syndromes suggested as associated with small mammals or birds. Honey Possums are tiny (8-12g) diprotodont marsupials that feed exclusively upon nectar and pollen, mainly at night. They were caught in four grids, in a line 42-72m apart, each grid containing 10x10 pitfall traps 5m apart. Five box traps were also used in each grid. Twenty trapping sessions, each of three consecutive nights, resulted in 1,371 captures of Honey Possums from 24,000 trapnights (5.7% trap success). Honey Possums accounted for 91% of all mammals caught; the Grey-bellied Dunnart Sminthopsis griseoventer, the Southern Bush Rat Rattus fuscipes, the House Mouse Mus musculus and the Ashy-grey Mouse Pseudomys albocinereus comprised the remainder. Overall, there appeared to be some correspondence between the capture rates of Honey Possums and the flowering patterns of some of their favoured plants, whereas temporal differences in the abundances of the five species of honeyeaters were not related in any simple manner to the magnitude of floral food resources (nectar and pollen), nor to invertebrate abundance. Birds were censused using instantaneous point counts in each trapping grid and six 12m long mist-nets operated regularly adjacent to the grids. During twenty trapping sessions, 2972 birds were recorded and 94% of these were honeyeaters. White-cheeked Honeyeaters Phylidonyris nigra and New Holland Honeyeaters Phylidonyris novaehollandiae accounted for 83% of all honeyeaters; Tawny-crowned Honeyeaters Phylidonyris melanops. Little Wattlebirds Anthochaera chrysoptera and Western Spinebills Acanthorhynchus superciliosis made up most of the remainder. More Honey Possums were caught and their condition indices were highest in winter, when up to six of their favoured food plants were in flower. Fewest Honey Possums were caught and condition indices were lowest in autumn, when fewest plants were in flower. In contrast, more honeyeater birds were present over summer and fewest during winter. Eight plant species within the Proteaceae were studied in detail. Three species, Banksia baueri, Banksia nutans and Dryandra plumosa, had floral characteristics typical of plants thought to be visited more frequently by mammals than birds. The remaining five species, Banksia baxteri, Banksia coccinea, Dryandra cuneata, Lambertia inermis and Adenanthos cuneatus displayed floral traits associated more with plants thought to be favoured by birds. However, temporal differences in the presentation of pollen (anthesis) and nectar, and amounts of nectar produced by these eight species did not conform to the predictions of separate mammals and bird pollination syndromes. Nonetheless, direct observations of foraging by Honey Possums and honeyeaters indicated preferences for flowers with two different suites of characteristics. Samples of pollen carried externally by 1218 Honey Possums and 1001 honeyeaters, and voided in faeces by 107 mammals and 225 birds, confirmed marked preferences for these different types of flowers. Flowers visited mostly by Honey Possums tended to occur low or on the ground, to be inconspicuous or hidden in foliage, drably coloured but with a distinctive odour. In contrast, flowers visited by honeyeaters were brightly coloured (red or yellow), exposed on the plant, often in a terminal position, and higher above the ground. Despite these clear preferences, especially evident when food from their favoured flowers was abundant, both Honey Possums and honeyeaters commonly visited flowers in both categories. Thus, although a degree of specialisation was apparent in the relationships between these nectarivorous vertebrates and their food plants, there was also opportunistic generalisation in flower usage. Honey Possums were highly sedentary, whereas most honeyeaters were transient in the area studied. Honey Possums are entirely dependent upon pollen grains for protein whereas honeyeaters also eat invertebrates. In consequence, Honey Possums appear more reliant than honeyeaters upon the floral products of a small suite of plants, but the dependence of these plants upon Honey Possums for pollination remains to be resolved.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Smith, Steven. "The Application of Molecular Genetics to Species Recovery Programs: Case Studies of Two Marsupial Reintroductions in Australia." Thesis, Griffith University, 2007. http://hdl.handle.net/10072/365972.

Повний текст джерела

Анотація:

An increasing number of endangered species have reached the threshold prompting management decisions to commence captive breeding and reintroduction. Such intervention is costly and requires a substantial investment of resources that might otherwise be spent on alternate conservation options. It is important, therefore, that such measures make use of all available information to ensure the success of the reintroduction effort, not just in the short-term but also well into the future. The diverse range of elements to be considered include habitat factors, number and sex ratio of founders, number of populations to establish, source populations to use, timing of releases and the need to supplement the populations. All of these factors can benefit through input from molecular genetic data to improve the quality of information used in decision making. Levels of genetic variation are strongly correlated with population fitness and their potential for long-term persistence. For this thesis I examined levels of genetic diversity at neutral and functional regions of the genome for two endangered species of Australian marsupials: the western barred bandicoot, Perameles bougainville; and Queensland populations of the greater bilby, Macrotis lagotis. These two species are under threat from similar processes: habitat destruction and modification for agriculture; predation by foxes and feral cats; changes to traditional fire regimes and competition with introduced pest species. Since European settlement, P. bougainville has become extinct on the mainland and now exists on just two islands in Shark Bay, Western Australia. Macrotis lagotis has suffered a range contraction of over 80% and the Queensland population has become disjointed from other populations to the west. Reintroduction efforts are under way for both species but, until now, the projects have not made use of molecular genetic data to inform their management decisions. I have used marker systems from nuclear microsatellite DNA, mitochondrial control region DNA and the functionally important major histocompatability complex (MHC) to assess levels of genetic diversity in natural, captive and reintroduced populations of both species. DNA was sourced from ear-tissue for P. bougainville and from ear-tissue and faecal pellets for M. lagotis. The levels of microsatellite diversity for the two natural populations of P. bougainville (Bernier Island: HE = 0.27± 0.1, A = 1.8± 0.3; Dorre Island: HE = 0.31± 0.1, A = 2.2± 0.4) were low compared to other marsupials and significantly lower than that recorded for the natural Queensland population of M. lagotis (Astrebla Downs: HE = 0.76 ± 0.03, A = 4.31 ± 0.3). In all cases, the diversity of captive and reintroduced populations was reduced relative to their source populations except for the Dryandra captive population of P. bougainville (HE = 0.54± 0.1, A = 2.69± 0.2) which was founded following a mixed breeding strategy using individuals sourced from both natural island populations. Distribution of mtDNA haplotypes among geographical regions indicated that, for each species, populations could be combined in captive breeding programs without compromising distinct evolutionary lineages. Design of MHC assays proved difficult for M. lagotis, but for P. bougainville two separate MHC class II alleles were identified. These two alleles were fixed across all individuals in all populations suggesting that they may represent two paralogous loci in P. bougainville and that MHC diversity is unusually low for this species. I have recommended that the recovery programs for both species be expanded to incorporate regular monitoring of molecular data to ensure that genetic diversity is retained and maximised in all populations. Where possible, the natural populations should be maintained as “pure lines” to increase overall species genetic diversity but the captive and reintroduced populations should make use of supplementary individuals from a mixture of sources to maximise variation and thus the adaptive potential of these populations in the novel environments to which they are being introduced.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Faculty of Science, Environment, Engineering and Technology
Full Text

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Roberts, Karen K. Biological Earth &amp Environmental Sciences Faculty of Science UNSW. "Oligo-Miocene pseudocheirid diversity and the early evolution of ringtail possums (Marsupialia)." Awarded By:University of New South Wales. Biological, Earth & Environmental Sciences, 2008. http://handle.unsw.edu.au/1959.4/41517.

Повний текст джерела

Анотація:

The marsupial family Pseudocheiridae is currently known from seventeen species of six genera in Australia and New Guinea. These small to medium-sized arboreal animals are nocturnal and folivorous. Extinct pseudocheirids are recognised from several mid to late Cenozoic fossil localities across Australia and New Guinea. The single largest collection of pseudocheirid fossils has been recovered from the Oligo-Miocene freshwater carbonates of the Riversleigh World Heritage Area in northwest Queensland. This collection, which includes the first pseudocheirid cranial fossils, forms the basis of this investigation. Three new extinct pseudocheirid genera together containing four species are identified and described. Six new species of Paljara, Marlu and Pildra are also described from Riversleigh. Two of the new Marlu species are reported from South Australia??s Leaf Locality. From Riversleigh, Marlu kutjamarpensis is identified and additional material of Paljara tirarensae and P. nancyhawardae documented. New species attributed to Marlu and Pildra necessitate revision of those genera. Cranial material is identified for three of the new species. The rostrum of archaic pseudocheirids is shorter than in extant forms but cranial morphology is similar overall. Phylogenetic relationships of all extinct pseudocheirids are analysed. They include all new and previously described species, most of which have never been examined in a parsimony-based analysis. Two hypotheses of pseudocheirid evolution are presented: a paired lineage hypothesis and a single lineage hypothesis. Both hypotheses demonstrate that species of Paljara are not the most plesiomorphic pseudocheirids, Marlu praecursor does not cluster with other species of Marlu, the new genus Gawinga is most closely related to Paljara and there are no representatives of the extant genus Pseudochirops in any pre-Pliocene locality. All extant pseudocheirids cluster to form a crown clade sister to a stem lineage of Pseudokoala and Marlu species. Pseudocheirids are found in all Oligo-Miocene faunal zones of Riversleigh. Species of Paljara and Marlu are most frequently recovered from Faunal Zone B and C deposits respectively. Four pseudocheirid species biostratigraphically correlate the Kutjamarpu local fauna of the Leaf Locality with Faunal Zones B and C of Riversleigh, suggesting an early to middle Miocene age for both deposits. Modern pseudocheirids first evolved no later than the late Miocene from a descendant of the Marlu + Pseudokoala lineage when all other Oligo-Miocene pseudocheirids became extinct. At least three pseudocheirid lineages dispersed to New Guinea approximately five million years ago, but ecological barriers probably prevented subsequent migrations between the two landmasses.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Crowther, Mathew S. "Variation and speciation within the Antechinus stuartii-A. flavipes complex (Marsupialia: Dasyuridae) in eastern Australia." Thesis, The University of Sydney, 2001. http://hdl.handle.net/2123/1018.

Повний текст джерела

Анотація:

Thesis (Ph. D.)--University of Sydney, 2001.
Title from title screen (viewed January 19, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Includes bibliographical references. Also available in print form.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Crowther, Mathew S. "Variation and speciation within the Antechinus stuartii-A. flavipes complex (Marsupialia: Dasyuridae) in eastern Australia." Connect to full text, 2001. http://ses.library.usyd.edu.au/handle/2123/1018.

Повний текст джерела

Анотація:

Thesis (Ph. D.)--University of Sydney, 2001.
Title from title screen (viewed January 19, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Includes bibliographical references. Also available in print form.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Hayward, Matt School of Biological Earth &amp Environmental Science UNSW. "The ecology of the quokka (Setonix brachyurus) (Macropodidae: Marsupialia) in the Northern Jarrah Forest of Australia." Awarded by:University of New South Wales. School of Biological, Earth and Environmental Science, 2002. http://handle.unsw.edu.au/1959.4/18768.

Повний текст джерела

Анотація:

The quokka (Setonix brachyurus Quoy & Gaimard 1830) is a medium-sized, macropodid marsupial that is endemic to the mesic, south-western corner of Australia. While being a tourist icon on Rottnest Island, the species is threatened with extinction. It has been intensively studied on Rottnest Island in the 1960s and 1970s, however very little is known of its ecology on the mainland. Additionally the insular and mainland environments are extremely different suggesting that ecological differences between the two populations are likely. Consequently, this study sought to determine the basic autecology of the quokka and identify what factors have attributed to its threatened conservation status. The northern jarrah forest of Western Australia was selected as the study region due to it being at the northern limit of extant quokka distribution and because it was thought that the factors threatening the quokka would be exacerbated there. Fossil deposits suggest that the quokka originally occupied an area of approximately 49,000 km2 in the south-western corner of Australia. Historical literature show that they were widespread and abundant when Europeans colonised the region in 1829 but a noticeable and dramatic decline occurred a century later. The arrival of the red fox to the region coincided almost exactly with this decline and so it was probably ultimately responsible. Continued predation by both it and the feral cat are likely to have continued the decline, along with habitat destruction and modification through altered fire regimes. Specific surveys and literature searches show that since the 1950s, the area occupied by the quokka has declined by 45% and since 1990 by 29%. Based on the criteria of the IUCN (Hilton-Taylor 2000), the conservation status of the quokka should remain as vulnerable. An endangered status may be more applicable if the quokkas restriction to patches through its existence as a metapopulation is considered. Trapping of eight sites supporting quokka populations in the mid-1990s revealed three sites now locally extinct despite the ongoing, six year old, fox control programme. Another three are at serious risk of extinction. Extant population sizes ranged from one to 36 and population density ranged from 0.07 to 4.3 individuals per hectare. This is considered to be below the carrying capacity of each site. The overall quokka population size in the northern jarrah forest may be as low as 150 adult individuals, of which half are likely to be female. Even the largest extant populations are highly susceptible to stochastic extinction events. This small size was surprising considering the six year old, introduced predator control programme. Historically, the restriction to discrete habitat patches, the occasional inter-patch movement, the lack of correlation between the dynamics of each population and reports of frequent localised extinctions and colonisations suggest that the quokka population once existed as part of a classic metapopulation. The massive decline of the quokka in the 1930s pushed the metapopulation structure into a non-equilibrium state such that today, the extant populations are the terminal remnants of the original classic metapopulation. Wild mainland quokkas breed throughout the year. A significant reduction in the number of births occurs over summer and this coincides with a decline in female body weight. Despite this, the mainland quokka is relatively fecund and is able to wean two offspring per year. The level of recruitment from pouch young to independence was low and this may explain the apparent lack of population increase following the initiation of fox control. A total of 56 trapped quokkas were fitted with a radio collar. Mean home range size for quokkas was 6.39 ha with a core range of 1.21 ha and this was negatively related to population density. Male home ranges were larger than females but not significantly when the sexual size dimorphism was considered. Nocturnal ranges were larger than diurnal ranges reflecting nocturnal departures from the swamp refugia. Home range sizes varied seasonally, probably due to changes in the distance required to move to obtain sufficient nutrients and water over the dry summer compared to the wet winter and spring. Telemetry confirmed trapping results that showed no movement between swamps or populations. Home range centres shifted to the periphery of the swamp following the winter inundation and this may increase the species susceptibility to predation. The lack of dispersal is probably caused by quokka populations existing below carrying capacity and following selection for philopatry under the threat of predation for dispersing individuals. Without dispersal to recolonise or rescue unpopulated patches, the collapse of the original quokka metapopulation appears to have occurred. On a macrohabitat scale, the quokka in the northern jarrah forest is restricted to Agonis swamp shrubland habitats that form in the open, upper reaches of creek systems on the western side of the forest. This restriction was probably initially due to the high water requirements of the quokka but is likely to have been exacerbated by increased predation pressure since the arrival of the fox. On a microhabitat scale, the quokka is a habitat specialist, preferring early seral stage swamp habitats, probably for foraging, as part of a mosaic of old age swamp that provides refuge. Despite the six year old, introduced predator control programme, foxes and cats are still the major cause of mortality to quokkas. Road kills was the other identifiable cause. Individuals alive at the start of the study had an 81% chance of staying alive until the end. The likelihood of dying was minimised by grouping together with conspecifics, maximising home range size and maximising the time spent within the swampy refuge. Current rates of adult and juvenile survivorship should allow population recovery and so it seems pouch young mortality, reflected by low recruitment, has inhibited the anticipated population increase following predator control. The confounding effect of inadequate unbaited controls meant that little statistical evidence was available on the impact of introduced predators on the quokka, however the models provided support for earlier hypotheses of these. The presence of a quokka population at a site was related to the amount of poison baits delivered ??? reflecting predation pressure, the average age of the swamp and a mosaic of early and late seral stages within the swamp habitat. Recently burnt habitat is thought to provide food for quokkas and long unburnt habitat provides refuge from predation.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Garkaklis, Mark Jurids. "Digging by the woylie Bettongia penicillata (Marsupialia) and its effects upon soil and landscape characteristics in a Western Australian woodland." Thesis, Garkaklis, Mark Jurids (2001) Digging by the woylie Bettongia penicillata (Marsupialia) and its effects upon soil and landscape characteristics in a Western Australian woodland. PhD thesis, Murdoch University, 2001. https://researchrepository.murdoch.edu.au/id/eprint/52132/.

Повний текст джерела

Анотація:

Until recently the potoroid rat kangaroo Bettongia penicillata (the woylie), once common and abundant across the southern third of Australia, was threatened with extinction, and restricted to three small populations in the southwest of Western Australia. Feral predator control and habitat management have seen a recovery in the populations of the woylie. This has provided an opportunity to study some of the functional relationships between this mycophageous marsupial and the environment it inhabits. The woylie feeds predominantly on the hypogeous faiiting bodies of ectomycorrhizal fungi, making diggings that disturb the soil surface. This study was the first to examine the impact of this digging activity (biopedturbation), on the edaphic and floristic structure of the ecosystems inhabited by woylies. An open population of 20 - 49 woylies was studied in a 70 ha area of the Dryandra Woodland, approximately 200 km to the southeast of Perth. The total number of woylie diggings estimated in the study site ranged from 5 000 ha^-1 year^-1 in April 1995 to 16 000 ha^-1 year^-1 in April 1996. This corresponds to a digging rate of between 38 to 115 diggings woylie^-1 night^-1, and an average soil turnover of approximately 6 tonnes woylie^-1 year^-1. No seasonal pattern in woylie digging activity was apparent. The decay process in woylie diggings was examined using simulated diggings. The average period of decay for diggings less than 60 mm in depth (mean depth = 45.0 ± 1.5 mm) was 29.5 ± 3.1 weeks. The average period of decay for diggings equal to or greater than 60 mm (mean depth 75.9 ± 3.1 mm) was 79 ± 10 weeks. There was a significant relationship between the initial depth of the digging and the period of decay (r^2 = 0.534, p < 0.001). Loose coarse organic material was found in all diggings before they were completely filled-in. Soils in the study site were found to be water repellent, usually in the top 1 cm of the soil, and as woylies forage for hypogeous fungi they disturb this surface layer. In situ measurements showed the undisturbed woodland soil surface was severely water repellent, whereas diggings had low water repellency and acted as preferential water infiltration paths after autumn rainfall events. In simulated diggings the low water repellence of the soil disappeared after approximately 2 years and organic material accumulated in the diggings, resulting in the formation of sub-surface water repellency at the base of the filled-in digging. In 25% of simulated diggings this buried organic material was invaded by masses of fungal hyphae which contributed significantly to the sub-surface water repellence. Thus, soil water repellency in the southwest of Western Australia is spatially and temporally heterogeneous and this heterogeneity is caused by digging animals. The distribution of soil nutrients, soil bulk density and soil particle size were also affected by woylie digging. In simulated diggings, available nitrate, ammonium and sulphur were significantly lower in decayed diggings than in undisturbed soils. Nitrate is susceptible to leaching in preferential water infiltration areas, whilst equilibrium reactions between ammonium and nitrate, and between sulphur and the mobile sulphate, can potentially result in decreases in both of these soil nutrients in water infiltration zones over time. Soil bulk density decreased significantly in both decayed simulated diggings and also at the larger quadrat scale. Areas excluded from woylie digging had a significantly higher soil bulk density than those subjected to digging, and excluded areas had soil bulk densities similar to woodlands where woylies did not occur. Remnant woodlands where digging animals are extinct may have soil physical properties that are less amenable to plant growth and productivity than where they are present. Soils in decayed diggings had a lower mean particle size, especially in soils with a high gravel content. The decay process favours the mobilisation of finer particles from the digging spoil which appear to wash back into the digging itself. The result is a surface soil with a heterogeneous particle size distribution. Digging by woylies results in patches of fine soil interspersed with coarse gravel piles on the surface. Woylie exclusion did not change plant recruitment or plant growth. Established woody perennials are unlikely to be grazed by woylies, which are predominantly mycophageous. Other studies have shown that a reduction in the productivity due to herbivory of plants that have symbiotic relationships with ectomycorrhizae results in a reduction in the productivity of mycorrhizal fungi. However, although this study showed no direct herbivory by woylies upon woody perennials, they were observed digging for the bulbs of hemicryptophytes (family Haemondoraceae) and also caching fruits of Santalum trees. Thus, direct interactions between the woylie and certain woodland species do occur. The soils of the southwest of Western Australia reflect deep in situ weathering of the laterite profile, indicative of a geologically stable environment. However, this study concludes that, at a smaller scale, southwestern Australian soils are subject to dynamic processes that create heterogenous soils, both spatially and temporally. The driving force behind these processes is the digging fauna. Digging is a significant perturbation in the environment and the changes that occur as a result of biopedturbation affect a number of important soil properties. The management of woodland and forest ecosystems where these fauna are now extinct may not reflect the true nature of these ecosystems and suggests that the maintenance of a diverse vertebrate fauna may be important to them.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Roulis, Eileen V. "The genetic diversity of Chlamydia pneumoniae and its implications for host and tissue specificity." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/96034/1/Eileen_Roulis_Thesis.pdf.

Повний текст джерела

Анотація:

Chlamydia pneumoniae is a wide spread human and animal pathogen, associated with a number of acute and chronic disease states. In this thesis, next-generation sequencing technologies were used to identify genetic markers involved in the diverse presentation of Chlamydia pneumoniae infections. The findings presented in this study describe a phylogenetically distinct human Chlamydia pneumoniae line, as well as a number of minor DNA sequence changes that may account for the biological fitness of particular strains to different diseases and animal hosts. The outcomes of this thesis have considerably expanded our knowledge of the genetic and evolutionary diversity of this common pathogen.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Stewart, Annabelle Greer. "Dibblers on the Jurien islands : the influence of burrowing seabirds and the potential for competition from other species." University of Western Australia. School of Animal Biology, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0066.

Повний текст джерела

Анотація:

[Truncated abstract] The dibbler, Parantechinus apicalis, is an endangered marsupial that exists on Boullanger, Whitlock and Escape islands off Jurien Bay in Western Australia. The introduced house mouse, Mus domesticus, exists on Boullanger and Whitlock islands, and the King’s skink, Egernia kingii, inhabits Boullanger and Escape islands. The grey-bellied dunnart, Sminthopsis griseoventer, exists on Boullanger Island. Over the last 150 years, the wedge-tailed shearwater, Puffinus pacificus, has colonised the islands to varying degrees. The interaction between dibblers and other island species is not clear. The purpose of this study was to determine the main factors regulating the dynamics of mammals, and in particular dibblers, on the Jurien islands. This was achieved by examining the effect of seabirds, the competitive interactions between species living on the islands, and seasonal changes in the environment. Animals were trapped for a period of 30 months, and their population structure, body condition, longevity, habitat preferences, diet and ecophysiology were examined. The results presented support the theory that by increasing soil nutrient concentrations, burrowing seabirds increase the primary productivity of islands, which has flow on effects to other trophic levels. Densities of seabirds and soil nutrient concentrations were highest on Whitlock Island, intermediate on Escape Island, and lowest on Boullanger Island . . .Thirty-five percent of dibblers on Escape Island were missing their tail or a limb, probably as a result of aggression from King’s skinks. Competition from high numbers of house mice on Boullanger Island, and from high numbers of King’s skinks on Escape Island, may increase the occurrence of male die-off on these islands. The better body condition and greater longevity of dibblers on Whitlock Island, despite high numbers of house mice, suggests that abundant resources are available to sustain both species. This study demonstrates that high densities of seabirds positively affect the population dynamics of mammals on the Jurien islands. Burrowing seabirds appear to influence the dynamics of dibblers more so than competition from house mice or King’s skinks. The findings from this study will assist the Dibbler Recovery Team with future management decisions regarding the viability of dibblers on the Jurien islands, and with decisions regarding the necessity to control house mouse numbers in the presence of native species.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Paull, David James Physical Environmental &amp Mathematical Sciences Australian Defence Force Academy UNSW. "Habitat fragmentation and the southern brown bandicoot Isoodon obesulus at multiple spatial scales." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Physical, Environmental and Mathematical Sciences, 2003. http://handle.unsw.edu.au/1959.4/38698.

Повний текст джерела

Анотація:

This thesis investigates the process of habitat fragmentation and the spatial and temporal scales at which it occurs. Fragmentation has become an important topic in biogeography and conservation biology because of the impacts it has upon species??? distributions and biodiversity. Various definitions of fragmentation are available but in this research it is considered to be the disruption of continuity, either natural or human-induced in its origins and operative at multiple spatial scales. Using the distribution of the southern brown bandicoot Isoodon obesulus as a case study, three spatial scales of fragmentation were analysed. At the continental scale, the Australian distribution of the subspecies I. o. obesulus was examined in relation to climate, geology and vegetation cover at the time of European settlement of Australia and two centuries later. Using archived wildlife records and Geographic Information Systems (GIS) analyses, habitat suitability models were created to assess natural and human-induced fragmentation of the distribution of I. obesulus in 1788 and 1988. At the regional scale, a study was made of the distribution of I. obesulus in the south-east of the State of South Australia. Again, natural and human-induced patterns of habitat fragmentation were modelled using GIS with climate, soil and vegetation data for the time of European settlement and at present. At the local scale, the distribution of I. obesulus was the subject of a detailed field survey of 372 sites within 29 remnant patches of native vegetation in south-eastern South Australia in order to understand the variables that cause habitat fragmentation. Geographic information systems were used again but in a different way to carefully stratify the field survey by overlaying maps of topography, vegetation and past fires. The large dataset collected from the surveys was described using six generalized linear models which identified the significant variables that fragment the distribution of I. obesulus at a local scale. From the results of the field surveys, a subset of four remnants was chosen for further GIS spatial modelling of the probability of I. obesulus occurring within remnants in response to fire via a controlled burning programme put in place to reduce accumulating fuel loads. These investigations show that habitat fragmentation can be caused by different factors at different spatial scales. At the continental scale, it was found that climate played a dominant role in influencing the fragmented distribution of I. obesulus but vegetation change during the past two centuries has also had a profound impact on the availability of habitat. Within south-eastern South Australia, the species??? regional scale distribution is constrained by climate and also by soil and vegetation patterns. Dramatic change to its regional distribution occurred in the 20th century as a result of the clearance of native vegetation for planting pastures, crops and pines. Fragmentation at the regional scale has resulted in the remaining habitat being reduced to small, isolated, remnant patches of native vegetation. At the local scale it was found that variables which disrupt the continuity of I. obesulus habitat within remnants include vegetation cover in the 0-1 m stratum, abundance of Xanthorrhoea australis and soil texture. For a subset of sites located in one landsystem of the study area, named Young, the age of vegetation since it was last burnt was also found to be a significant variable, with vegetation 10-14 years old since burning providing the most suitable habitat. Spatial modelling of two scenarios for prescribed burning over 15 years revealed that the use of fire as a habitat enhancement tool will be complicated and require a detailed understanding of the factors that cause natural fragmentation in the distribution of I. obesulus at the local scale. A further conclusion of the study was that ecological relationships between species and their habitats require careful interpretation of multi-scaled datasets and conservation plans for endangered species ought to be made at multiple spatial scales. Future research directions are identified including the linking of multi-scaled habitat fragmentation models to genetic studies of the species throughout its range.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Fuss, Janet Megan. "Retinal anatomy of Australian marsupials." Thesis, 1986. http://hdl.handle.net/2440/122146.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Coldham, Thosaporn. "The detection and characterisation of Helicobacter species in Australian marsupials." 2004. http://www.library.unsw.edu.au/~thesis/adt-NUN/public/adt-NUN20051219.150811/index.html.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Czarny, Natasha. "Advances in assisted reproductive techniques for the conservation of Australian carnivorous marsupials." Thesis, 2009. http://hdl.handle.net/1959.13/44623.

Повний текст джерела

Анотація:

Research Doctorate - Doctor of Philosophy (PhD )
In Australia almost 40% of the carnivorous marsupials, or dasyurids, are threatened. Assisted reproductive techniques (ART), especially genome resource banking, have the potential to contribute to the conservation of these species by reducing the loss of genetic diversity. This project aimed to advance the knowledge of ART in dasyurids by focusing on the long term preservation of male and female gametes and establishing protocols for the production of mature oocytes for use in future ART. These studies used the fat tailed dunnart (Sminthopsis crassicaudata) as a model dasyurid and replicated many of the findings on threatened dasyurids. Dasyurid spermatozoa had a relatively unstable acrosome which lacked acrosomal membrane disulphide stabilisation. There was no evidence that S. crassicaudata spermatozoa were susceptible to high concentrations of cryoprotectants, but spermatozoa frozen with up to 40% glycerol using a rapid freezing protocol were not viable. Nonetheless the morphology and acrosomal integrity of frozen spermatozoa was normal and there was no evidence of DNA damage. The lack of success with cryopreservation is likely to be an artifact of cold shock, which was observed in S. crassicaudata and had not previously been described in any other marsupial. This susceptibility to low temperature can be overcome by slow cooling spermatozoa to 0 ºC at 0.5 ºC minute -1 with up to 20% egg yolk, and it is likely that this finding will result in successful sperm cryopreservation in the near future. Freeze drying spermatozoa represents an additional strategy for long term sperm preservation and freeze dried S. crassicaudata spermatozoa had normal morphology and nuclear integrity. In this study preserved dasyurid spermatozoa were immotile and non-viable but had no nuclear damage, suggesting that fertilisation may be achieved with intracytoplasmic sperm injection (ICSI). As ICSI requires a large number of mature oocytes to be collected, a reliable timed ovarian stimulation protocol was established in S. crassicaudata. This protocol enabled the collection of up to 28 oocytes which were either mature, or able to be cultured to the first polar body stage within 48 hours. Despite the success of induced ovulation, methods for preservation of the female gamete are essential to genome resource banking. This study also described a protocol for the enzymatic dissociation of dasyurid ovarian tissue allowing collection of high quality individual preantral follicles. The oocytes inside these follicles were able to be vitrified without any loss of viability and short term in vitro culture of immature follicles repaired the small amount of vitrification-induced damage to the surrounding granulosa cells. This collection of studies describes progress in genome resource banking for spermatozoa and oocytes from dasyurids and the development of protocols allowing the collection of a large number of oocytes for use in fertilisation experiments. These advances provide a solid and comprehensive framework for continuing the study of dasyurid ART which is timely due to the urgent need for genome resource banking in several threatened dasyurid marsupials.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Czarny, Natasha. "Advances in assisted reproductive techniques for the conservation of Australian carnivorous marsupials." 2009. http://hdl.handle.net/1959.13/44623.

Повний текст джерела

Анотація:

Research Doctorate - Doctor of Philosophy (PhD )
In Australia almost 40% of the carnivorous marsupials, or dasyurids, are threatened. Assisted reproductive techniques (ART), especially genome resource banking, have the potential to contribute to the conservation of these species by reducing the loss of genetic diversity. This project aimed to advance the knowledge of ART in dasyurids by focusing on the long term preservation of male and female gametes and establishing protocols for the production of mature oocytes for use in future ART. These studies used the fat tailed dunnart (Sminthopsis crassicaudata) as a model dasyurid and replicated many of the findings on threatened dasyurids. Dasyurid spermatozoa had a relatively unstable acrosome which lacked acrosomal membrane disulphide stabilisation. There was no evidence that S. crassicaudata spermatozoa were susceptible to high concentrations of cryoprotectants, but spermatozoa frozen with up to 40% glycerol using a rapid freezing protocol were not viable. Nonetheless the morphology and acrosomal integrity of frozen spermatozoa was normal and there was no evidence of DNA damage. The lack of success with cryopreservation is likely to be an artifact of cold shock, which was observed in S. crassicaudata and had not previously been described in any other marsupial. This susceptibility to low temperature can be overcome by slow cooling spermatozoa to 0 ºC at 0.5 ºC minute -1 with up to 20% egg yolk, and it is likely that this finding will result in successful sperm cryopreservation in the near future. Freeze drying spermatozoa represents an additional strategy for long term sperm preservation and freeze dried S. crassicaudata spermatozoa had normal morphology and nuclear integrity. In this study preserved dasyurid spermatozoa were immotile and non-viable but had no nuclear damage, suggesting that fertilisation may be achieved with intracytoplasmic sperm injection (ICSI). As ICSI requires a large number of mature oocytes to be collected, a reliable timed ovarian stimulation protocol was established in S. crassicaudata. This protocol enabled the collection of up to 28 oocytes which were either mature, or able to be cultured to the first polar body stage within 48 hours. Despite the success of induced ovulation, methods for preservation of the female gamete are essential to genome resource banking. This study also described a protocol for the enzymatic dissociation of dasyurid ovarian tissue allowing collection of high quality individual preantral follicles. The oocytes inside these follicles were able to be vitrified without any loss of viability and short term in vitro culture of immature follicles repaired the small amount of vitrification-induced damage to the surrounding granulosa cells. This collection of studies describes progress in genome resource banking for spermatozoa and oocytes from dasyurids and the development of protocols allowing the collection of a large number of oocytes for use in fertilisation experiments. These advances provide a solid and comprehensive framework for continuing the study of dasyurid ART which is timely due to the urgent need for genome resource banking in several threatened dasyurid marsupials.

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Morris, SD. "Process-explicit approaches to predicting and managing range changes in Australian marsupials." Thesis, 2021. https://eprints.utas.edu.au/38176/1/Morris_whole_thesis.pdf.

Повний текст джерела

Анотація:

A species’ range—the geographical area over which it is found—is determined by many interacting factors. Outside of small-island settings, the broadest determinant is typically climate, which interacts with biotic factors (predation, competition, pathogens, etc.), human influences including land use, and other abiotic factors (geology, soil chemistry, etc.). Global warming will, therefore, cause many species to either change their range or change how the factors shaping their range interact. Paradoxically, it is projected that to prevent the worst outcomes associated with the resultant geographical redistribution of the world’s species due to climate change, we might have to actively and pre-emptively redistribute species ourselves. These movements of species for conservation purposes have been termed conservation translocations. To understand natural range changes and plan conservation translocations, we need accurate predictions of suitable conditions and habitat—a task that has become a key applied goal of biogeography and ecology. Better predictions will enable more effective and efficient management of endangered species, pests, and pathogens. Currently, the most popular method for implementing these predictions is the Species Distribution Model (SDM). This broad group of techniques can be split into two strategies: correlative (pattern oriented) and mechanistic (process-explicit). Each have their associated advantages and disadvantages relating to their underlying assumptions and ease of use. In this thesis, I examined the geographic ranges of three Australian marsupials in the past, present, and future; identify translocation sites for the contemporary cases; and sought to distinguish the characteristics of successful translocations globally. Specifically, I aimed to : (i) undertake a systematic review to identify the features of successful and failed conservation translocations, (ii) assess the role of past climate change on the mainland of Australia in the extirpation of the Tasmanian devil (Sarcophilus harrisii), (iii) identify current translocation sites for the vulnerable brush-tailed rock-wallaby (Petrogale pencillata), and (iv) quantify the effect of future climate change on Australia’s only hibernating marsupial, the mountain pygmy possum (Burramys parvus), and evaluate potential sites for its translocation. I found that translocation success is positively affected by investment—greater number of individuals over longer periods—though historical context is important—Oceania’s difficulty in controlling invasive species is the likely reason it had less positive outcomes than Europe or North America. I showed that there is no clear evidence, using process-explicit SDMs, for invoking climate change as the sole cause of the loss of the Tasmanian devil from mainland Australia in the Holocene, and consequently other factors, such as human intensification and dingoes, must be involved. I demonstrate that parts of Tasmania seem to be an ideal and immediate climate-habitat refuge for the highly endangered southern population of brush-tailed rock-wallabies and potentially also the critically endangered mountain pygmy possum in the future. I show the importance of food availability for the mountain pygmy possum if it is to cope with a rapidly changing alpine climate. Although our ability to predict species’ distributional changes has improved in recent decades, the fact that ranges are an emergent property of a variety of processes means that many challenges (scientific and conservation management) are still to come. However, process-explicit SDMs and ecologically relevant predictors in correlative SDMs provide viable platforms to meet these challenges, as demonstrated in this thesis.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Fraser, TA. "Diagnostics and molecular epidemiology of the Sarcoptes scabiei mite infesting Australian wildlife." Thesis, 2018. https://eprints.utas.edu.au/30875/1/Fraser_whole_thesis.pdf.

Повний текст джерела

Анотація:

Parasitic infestations have always been a noteworthy topic for human and animal health globally, with many considered a result of spill-over and zoonosis. One such parasite, Sarcoptes scabiei, is known to infest over 300 million humans per year and has been documented in over 104 mammals. It has recently been classified as a neglected tropical disease and is among the top 50 most prevalent human diseases. With uncertainty over (i) the global epidemiology of S. scabiei and (ii) the reliability of current diagnostics methods, much still needs to be understood if stakeholders are to successfully develop strategies to control this parasite. The overall objective of this thesis was to study the molecular epidemiology and genetic typing of S. scabiei infesting Australian animals and assess the diagnostic methods for sarcoptic mange. At the global scale, numerous genetic studies have attempted to reveal how the host species and host geographic location influence S. scabiei phylogenetics. By performing an analysis of the global literature (Chapter 2), I was able to reveal that there were inconsistencies in gene loci and phylogenetic conclusions used in these previous studies. Furthermore, by executing a contemporary analytical approach employing molecular markers on existing S. scabiei sequences, it was apparent that (i) new S. scabiei samples, (ii) appropriate gene loci targets, and (iii) advanced phylogenetic approaches are necessary to more confidently comprehend the origins of mange in Australia. As there were only a limited number of Australian marsupial-derived S. scabiei sequences, and that three of the most commonly used gene loci used for typing are located within the mitochondria, I performed mitochondrial genome sequencing of mites collected from koalas and wombats (Chapter 3). It was revealed that there is a high sequence similarity not just within marsupial S. scabiei mites, but also to the only human-derived S. scabiei mitochondrial genome. Furthermore, by examining individual gene phylogenies, I concluded that cox1 is the most informative gene as the cox1 phylogeny inferred was consistent with the complete mitochondrial genome phylogeny with the highest resolution of ancestral lineages. Building on the identification of cox1 as an informative gene target, I greatly expanded the molecular typing of S. scabiei within Australia (Chapter 4). I identified that mites collected from koalas, wombats, foxes and dogs across five states of Australia were unable to be phylogenetically separated by their host or location. Thus, I considered it highly plausible that multiple spill-over events may have occurred in Australia, as many haplotypes are identical to European and non-European sequences. Furthermore, I suggested that it is likely that canids are the source for transmission of mange throughout Australian wildlife as dogs and foxes share identical haplotypes to wombats and koalas. Finally, I detected a distinguishable human-specific lineage, distinct from the dominant mixed animal clade. Clinical diagnosis of mange/scabies typically involves the collection of skin scrapings followed by microscopic detection of the mite. This method yields results with a high risk of false negatives, however. I performed the first comparative S. scabiei diagnostic study on a unique sample set collected from bare-nosed wombats. Here, I assessed a variety of putatively useful approaches including observational scoring, microscopy, PCR on skin scraping DNA and PCR on skin swab DNA (Chapter 5). I concluded that: (i) observational scoring positively correlated with counts from microscopy, however this approach tended to under-diagnose early mange; (ii) species-specific S. scabiei PCR enhanced the sensitivity of mite detection in relation to microscopy and; (iii) swabs as a method for sample collection is questionable due to inadequate host cell uptake and likelihood of producing false negatives. Finally, I sought to improve the use of molecular techniques for S. scabiei diagnosis (Chapter 6). I developed a novel rapid diagnostic tool using a Loop Mediated Isothermal Amplification assay, which I demonstrated to be specific to S. scabiei and able to produce a rapid diagnostic result within 30 minutes. Since this method can be performed without advanced laboratory equipment, this development has potential direct roles as an ancillary method with microscopy at the point-of-care to reduce the number of potential S. scabiei false-negative results obtained by microscopy alone in both human and veterinary settings. In summary, this thesis has contributed to: (i) the expansion of S. scabiei phylogeny by highlighting the high genetic variability of the single mite species; (ii) suggested multiple spill-over events may be the consequence of inadequate screening of imports/exports possibly globally and; (iii) has demonstrated the incompatible variety of different diagnostic methods for S. scabiei which may be supplemented with the development of a new highly sensitive and specific molecular technique. The contributions I have made in S. scabiei research will aid in future conservation efforts to aid in understanding transmission risks to threatened populations and enhance diagnostic procedures in clinical, field and remote settings.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Davey, Stuart McDonald. "The environmental relationships of arboreal marsupials in a eucalypt forest : a basis for Australian forest wildlife management." Phd thesis, 1989. http://hdl.handle.net/1885/142232.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Stannard, Hayley J. "Diet, nutrition and haematology of Dasyurid marsupials." Thesis, 2012. http://handle.uws.edu.au:8081/1959.7/515046.

Повний текст джерела

Анотація:

This thesis examines aspects of the biology of six Dasyurid species, which are a family of insectivorous and/or carnivorous Australian marsupials. In particular diet, nutrition and haematology were studied. Diet and nutrition were studied to obtain information on diet choice by translocated animals and diet digestibility in captive animals. Haematology was studied in captivity as it is associated with clinical health and is influenced by nutrition. The six species used for the study were part of captive colonies housed at the University of Western Sydney, the University of Sydney, Alice Springs Desert Park, Australian Ecosystems Foundation Inc., and Featherdale Wildlife Park. The broad aim of the study was to aid current wildlife management practices and future conservation efforts (such as reintroduction and translocation programs) for these six species and other marsupial species in Australia. Examination of the diet of a population of translocated red-tailed phascogales (Phascogale calura) at Alice Springs Desert Park showed that they are primarily insectivorous with 92.6% of all scats containing arthropods. They are also opportunistic predators within the park, consuming birds (51.6%), small mammals (33.3%) and on occasion reptiles, and plant material (27.4%). A seasonal variation in diet was found between spring and summer, due to a larger portion of birds present in the diet in spring. The red-tailed phascogales were able to exploit a number of prey types and it is therefore likely that they would survive a ‘hard’ translocation into the wild provided the site chosen has an adequate food supply. Investigation of the gastrointestinal tract of the kultarr (Antechinomys laniger) shows that on gross examination it is simple with no differentiation between the small and large intestine, and lacked a caecum. Mean gross length of the kultarr digestive tract was 165.2 ± 32.1 mm. Microscopically, the tissues appeared healthy with cell types similar to other mammals. Rate of passage through the kultarr digestive tract was rapid, measuring 1.6 ± 0.2 h and mean retention time 3.9 ± 1.2 h. The rapid transit time was consistent for an animal of equivalent body mass, dietary preference and gastrointestinal tract morphology. Study of nutrition in red-tailed phascogales and kultarrs showed apparent digestibility values were above 81% for dry matter, energy, protein and lipids on a number of captive fed diets. No significant difference was found between phascogales and kultarrs when maintained on the same diet for apparent digestibility of dry matter, energy, protein and lipids. Maintenance energy requirements were determined to be 954 kJ kg0.75 d-1 for the red-tailed phascogale and 695 kJ kg0.75 d-1 for the kultarr. Digestion studies undertaken on stripe-faced dunnarts (Sminthopsis macroura) and fat-tailed dunnarts (Sminthopsis crassicaudata) showed that depending on the diet, the digestible energy intake of the stripe-faced dunnart ranged from 359 to 816 kJ kg -0.75 d-1 and digestible intake ranged from 542 to 990 kJ kg -0.75 d-1 for the fat-tailed dunnarts. Both dunnart species had varied absorption of minerals with higher values observed for Na, P and K compared to the other minerals studied. The morphology of the gastrointestinal tracts of both dunnart species were simple and consisted of a unilocular stomach and relatively uniform intestine, like that of the kultarr. The length of the intestine of the stripe-faced dunnart ranged from 84 to 129 mm and that of the fat-tailed dunnart 78 to 131 mm. Fat-tailed dunnarts need to consume more nutrients per unit of body mass for maintenance in captivity compared with stripe-faced dunnarts. Studying digestibility in a larger Dasyurid species, the eastern quoll (Dasyurus viverrinus), showed they had high apparent digestibility values for dry matter, gross energy, protein and lipids (>84%). There was a significant difference in apparent digestibility of dry matter, gross energy and protein between the two diets provided: kangaroo mince and chicken necks. Analysis of blood parameters in the eastern and spotted-tailed quoll provided new data for blood chemistry and differential white cell values. For many of the parameters, blood chemistry results were comparable to other marsupials and no significant differences bilirubin, glucose, creatinine and sodium levels in the eastern quoll. Generally higher levels for these parameters were observed in summer; however, in autumn (southern hemisphere) sodium levels were significantly higher. Eastern quolls one year of age and under had significantly (P<0.05) higher alkaline phosphatase values than older animals. The values obtained in this study can be used to assess clinical health of quolls and will assist with captive management and future reintroduction programs. The results from this thesis have implications for captive management and future conservation efforts for Dasyurids. The study has shown the diet choice of translocated phascogales in a new environment, which has contributed to improving translocation techniques used for this species. Nutritional experiments suggest that no single diet, if fed alone is appropriate for feeding captive dasyurids; and live insect diets provide behavioural enrichment, and enhance mental and physical stimulation. The ability of captive animals to catch live food also increases the likelihood of their survival postrelease, if they are subject to translocation in the future. Energy requirements differ between species and do not necessarily relate to body mass but likely relate to physiological adaptations and ecology of the species. The data gained in this study has been incorporated into the daily management/husbandry practices for these species; it can also be used as a model for other Dasyurids. The data has also contributed to the paucity of biological data available on Dasyurids and will contribute to conservation of Australian native species.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Foster, Wendy Kay. "Reproductive strategies of the red-tailed phascogale (Phascogale calura)." 2008. http://hdl.handle.net/2440/49885.

Повний текст джерела

Анотація:

This thesis examines the reproductive biology of red-tailed phascogales, an obligate male semelparous dasyurid species, which is part of a captive breeding colony at Alice Springs Desert Park. The red-tailed phascogale belongs to a group of dasyurids that shows an unusual reproductive strategy amongst mammals, one which provides opportunity for understanding means by which individuals maximise their reproductive success and the role of sperm competition. The broad aim was to gain an understanding of the reproductive biology of red-tailed phascogales and explore means by which individuals can affect their reproductive success. Examination of the red-tailed phascogale reproductive biology showed that females mated with multiple males and were capable of storing sperm in their oviducts for at least a five day period. Captive female red-tailed phascogales showed greater plasticity in their breeding season than has been observed in Antechinus, which exhibits the same life history strategy. Females were observed to invest heavily into the production of young, producing almost twice as many ova (15.1 ± 1.9) as young they can raise and 76% of females filling six to eight of the eight available teats in a breeding attempt. A 63% male bias was observed in young attaching to the teats, which could be produced through differential attachment of the sexes to teats at birth. Of the 846 young born in the captive breeding colony, 68% were weaned, with weaning occurring between 90-110 days of age and a 53% female bias observed in young being weaned. By weaning, a litter of young weighed 380% of the mothers mass with male young tending to be heavier than females by weaning. No relationship was observed between maternal weight and either litter sex ratio or sex biased growth of young. A positive relationship between maternal body mass and body mass of offspring at weaning was observed, with the body mass of young at weaning correlated with its body mass at maturity. Multiple paternity was observed in more than half of the litters examined, with heavier males having increased siring success compared to lighter males. Genotyping showed that the effective population size for the captive colony was 1.9x that observed from the group managed studbook. Male reproduction was also not as tightly constrained as in Antechinus, with spermatogenic failure not occurring in captive populations until after mating had occurred, meaning males are not reliant on epididymal stores alone for successful breeding. Scrotal diameter showed a positive relationship with testis and epididymal mass across male life, although this relationship was not evident when analysis was restricted to the time of peak sperm production. Captive males showed the opposite pattern of testosterone fluctuations to that observed in wild animals, with lowest levels occurring during the mating period. Captive animals were able to survive up to five years in captivity, in contrast to the obligate semelparity observed in wild males. Although most captive females can survive to breed in a second year and females are known to breed in a second year in the wild, the reproductive strategy of females appears to be aimed at maximising the returns on their first breeding attempt. In males, the need to maximise the investment into the first breeding season is amplified through the complete absence of opportunity to breed again; either through post-mating mortality in the wild or spermatogenic failure in captivity. The results of this study have implications for captive breeding of red-tailed phascogales, with their reproductive biology; spermatogenic failure, restricted breeding season, teat number limiting the number of young raised, high lactational investment into young, sex biases, the need to maintain genetic diversity and biases in siring success; providing challenges for the maintenance of a captive population. The results of this study also provide comparative information that contributes to understanding the unusual life history strategy of Phascogale and Antechinus, and contributes to the growing body of knowledge about mating strategies in marsupials.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1330358
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2008

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Foster, Wendy Kay. "Reproductive strategies of the red-tailed phascogale (Phascogale calura)." Thesis, 2008. http://hdl.handle.net/2440/49885.

Повний текст джерела

Анотація:

This thesis examines the reproductive biology of red-tailed phascogales, an obligate male semelparous dasyurid species, which is part of a captive breeding colony at Alice Springs Desert Park. The red-tailed phascogale belongs to a group of dasyurids that shows an unusual reproductive strategy amongst mammals, one which provides opportunity for understanding means by which individuals maximise their reproductive success and the role of sperm competition. The broad aim was to gain an understanding of the reproductive biology of red-tailed phascogales and explore means by which individuals can affect their reproductive success. Examination of the red-tailed phascogale reproductive biology showed that females mated with multiple males and were capable of storing sperm in their oviducts for at least a five day period. Captive female red-tailed phascogales showed greater plasticity in their breeding season than has been observed in Antechinus, which exhibits the same life history strategy. Females were observed to invest heavily into the production of young, producing almost twice as many ova (15.1 ± 1.9) as young they can raise and 76% of females filling six to eight of the eight available teats in a breeding attempt. A 63% male bias was observed in young attaching to the teats, which could be produced through differential attachment of the sexes to teats at birth. Of the 846 young born in the captive breeding colony, 68% were weaned, with weaning occurring between 90-110 days of age and a 53% female bias observed in young being weaned. By weaning, a litter of young weighed 380% of the mothers mass with male young tending to be heavier than females by weaning. No relationship was observed between maternal weight and either litter sex ratio or sex biased growth of young. A positive relationship between maternal body mass and body mass of offspring at weaning was observed, with the body mass of young at weaning correlated with its body mass at maturity. Multiple paternity was observed in more than half of the litters examined, with heavier males having increased siring success compared to lighter males. Genotyping showed that the effective population size for the captive colony was 1.9x that observed from the group managed studbook. Male reproduction was also not as tightly constrained as in Antechinus, with spermatogenic failure not occurring in captive populations until after mating had occurred, meaning males are not reliant on epididymal stores alone for successful breeding. Scrotal diameter showed a positive relationship with testis and epididymal mass across male life, although this relationship was not evident when analysis was restricted to the time of peak sperm production. Captive males showed the opposite pattern of testosterone fluctuations to that observed in wild animals, with lowest levels occurring during the mating period. Captive animals were able to survive up to five years in captivity, in contrast to the obligate semelparity observed in wild males. Although most captive females can survive to breed in a second year and females are known to breed in a second year in the wild, the reproductive strategy of females appears to be aimed at maximising the returns on their first breeding attempt. In males, the need to maximise the investment into the first breeding season is amplified through the complete absence of opportunity to breed again; either through post-mating mortality in the wild or spermatogenic failure in captivity. The results of this study have implications for captive breeding of red-tailed phascogales, with their reproductive biology; spermatogenic failure, restricted breeding season, teat number limiting the number of young raised, high lactational investment into young, sex biases, the need to maintain genetic diversity and biases in siring success; providing challenges for the maintenance of a captive population. The results of this study also provide comparative information that contributes to understanding the unusual life history strategy of Phascogale and Antechinus, and contributes to the growing body of knowledge about mating strategies in marsupials.
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2008

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Charalambous, Renae. "Understanding the physiological impacts of stress on the Australian marsupial species, the Koala (Phascolarctos cinereus), within New South Wales and South Australia." Thesis, 2019. http://hdl.handle.net/1959.7/uws:54050.

Повний текст джерела

Анотація:

The koala (Phascolactos cinereus) is currently listed by the IUCN as vulnerable toextinction with a decreasing population trend. This listing can be attributed to both therecent climate trends impacting ecosystems, and human induced environmental changefrom extensive land clearing and habitat fragmentation. These have both been proven toinduce stress, which in turn influences the onset of disease. This study performed aretrospective analysis whereby admission records for 12,543 wild, rescued koalasadmitted into clinical care within New South Wales were studied in order to determinetrends in clinical admissions and diagnosis over a period of 29 years. Results indicatedthat between all three locations (Port Stephens, Port Macquarie and Lismore), the mostcommon prognosis for koalas admitted into care was disease, the most common diseasefor koalas admitted into care was signs of chlamydia, and the most common outcome forkoalas admitted into care was released. Within Port Stephens, mature aged and femalekoalas were found to have more disease than any other age or gender, while juvenile agedand male koalas were found to be released more than any other age or gender.Additionally, there were fewer koalas with disease and fewer koalas released in PortStephens as each year progressed. Within Port Macquarie, mature aged and male koalaswere found to have more disease than any other age or gender, while juvenile aged andfemale koalas were found to be released more than any other age or gender. Additionally,there were more koalas with disease and fewer koalas released in Port Macquarie as eachyear progressed. Within Lismore, adult aged and female koalas were found to have moredisease than any other age or gender, while joey aged and male koalas were found to bereleased more than any other age or gender. Additionally, there were more koalas withdisease and fewer koalas released in Lismore as each year progressed. Determiningtrends in clinical admissions and diagnosis over such a substantial period of time is animportant determinant for the continuing decline of koalas throughout Australia, and inparticular New South Wales. It is integral that any further decline of koala populations isprevented, however this can only be achieved through informed recommendationsthrough research projects such as these.

Стилі APA, Harvard, Vancouver, ISO та ін.

Дисертації з теми "Australian marsupials"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями