Dissertations / Theses on the topic 'Koalas'
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1
Ward, Steven J., University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "Koalas and the community : a study of low density populations in Southern Sydney." THESIS_CSTE_SFH_Ward_S.xml, 2002. http://handle.uws.edu.au:8081/1959.7/265.
Abstract:
The aim of this study was to investigate the distribution, density, health, condition, fertility, causes of mortality, home range size and tree preferences, of koalas in low density populations in the south of Sydney. This information was then used to make management recommendations; good management is needed because there is rapid human population growth and pressure for development of koala habitat in the Sydney region. State Environment Planning Policy 44(SEPP44) is New South Wales legislation that relates to developments affecting koala habitat. Problems in the application of SEPP44 in the Sydney region were found to exist, such as Sutherland Local Government Area (LGA) not being covered, and changes to this legislation are also recommended.Doctor of Philosophy (PhD)
2
Maher, Iona Elizabeth. "Investigations into the effect of koala retrovirus infection on the immune system of koalas." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16995.
Abstract:
The aim of this thesis is to investigate the effect of infection with Koala retrovirus (KoRV) on the immune system of koalas. This required the development of real-time RT-PCR assays to measure key cytokines including interleukin 4, interleukin 6, interleukin 10 and interferon gamma and CD4 and CD8β. The response of koala cells to three common mitogen stimulation protocols was assessed and appropriate reference genes (GAPDH and 28s) were validated. These qPCR methods were then used to examine the resting cytokine and CD4:CD8 mRNA expression in Victorian koalas that had either negative, positive or mixed KoRV and Chlamydia infection status. KoRV positive koalas had significantly lower levels of IL17A and IFNγ expression along with a decreased CD4:CD8 compared to negative koalas. qPCR was also used to measure gene expression by mitogen stimulated lymphocytes of koalas infected with a newly discovered variant of KoRV (KoRV B) compared to those without; this was measured four times to control for seasonal variation. KoRV B positive koalas showed significantly increased upregulation of IL17A and IL10 in three out of four sampling periods and IFNγ, IL6, IL4 and TNFα in two out of four. There was also seasonal variation in up-regulation for most cytokines and the CD4:CD8. qPCR was used to detect KoRV A and B from DNA samples from koalas in eight geographically separate populations in NSW. KoRV A was detected in 217/217 of koalas, thus it is likely endogenous in NSW. KoRV B was detected in 21/217 individuals and in all but one population examined in NSW. A pilot study was performed to establish a protocol for incubation of the synthetic peptide CKS-17 (immunosuppressive domain of gamma retroviruses), with mitogen stimulated PBMC’s from KoRV positive and KoRV negative koalas.
3
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.
Abstract:
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.
4
Rademann, Matthias. "Morphologische und morphometrische Untersuchung des Dickdarmes der Koalas, einschliesslich einer vergleichenden Gegenüberstellung der Darmtrakte von Koala, Schwein und Pferd." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967836220.
5
Hey, Grace Valasi, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "Identification of individual koalas: microsatellite analysis of faecal DNA." THESIS_CSTE_SFH_Hey_G.xml, 2003. http://handle.uws.edu.au:8081/1959.7/451.
Abstract:
Current studies of koalas in the wild mainly rely on information gathered by traditional field methods, such as community sightings, spotlighting, radiotracking, animal trappings, ear tagging and faecal pellet incidence. Collection of faeces is potentially the most reliable source of non-invasively obtaining DNA samples, which can be used to identify specific individuals. This thesis demonstrated a simple, rapid and reproducible method of extracting DNA from Koala faecal pellets using a commercially available DNA extraction kit, shows the maximum age of pellets from which DNA can be reliably extracted and defines the conditions required for the long term storage of pellets before DNA extraction is carried out. Mitochondrial DNA PCR analysis provided a simple and rapid indication of the success of both the faecal DNA extraction and pellet collection process. The faecal DNA was successfully used for microsatellite analysis and the subsequent genetic profiling of individuals from within the Campbelltown Koala population. The study paves the way for the analysis of microsatellite loci in koala faecal pellet DAN to study populations, which are too sparsely distributed to allow the capture of individual koalasMaster of Science (M. Sc.) (Hons.)
6
Lima, Eliana Maciel Barros. "Seletividade alimentar dos koalas do Jardim Zoológico de Lisboa." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2013. http://hdl.handle.net/10400.5/6194.
Abstract:
Dissertação de Mestrado Integrado em Medicina VeterináriaO objetivo deste trabalho foi estudar a seletividade alimentar dos koalas do Jardim Zoológico de Lisboa. Para tal, efetuou-se uma análise estatística dos registos diários sobre o consumo dos mesmos, recolhidos pelos seus tratadores no período compreendido entre 2008 e 2012, conduziram-se testes de cafetaria para analisar as preferências alimentares destes animais e determinados aspetos do seu comportamento alimentar, e, por último, determinou-se o conteúdo nutricional (matéria seca, cinza, fibra e proteína) de 54 amostras de eucalipto fornecido aos koalas. Os animais estudados têm acesso a uma dieta diversificada (cerca de 30 espécies de eucalipto), o que permite um elevado nível de seletividade. As análises estatísticas mostraram diferenças significativas (P ≤ 0,05) entre o nível de preferência médio individual dos koalas do Jardim Zoológico de Lisboa, o que pode estar relacionado com diferenças fisiológicas (sexo, idade, estado reprodutivo) e/ou com experiências alimentares prévias. Os indivíduos analisados mostraram um nível de preferência superior para determinadas espécies de eucalipto, tais como Eucalyptus botryoides, E. camaldulensis, E. globulus, E. macarthuri, E. occidentalis, E. ovata, E. polyanthemus, E. robusta e E. tereticornis. Foi detetada variação dos níveis médios de preferências ao longo do ano das espécies de eucalipto mais frequentemente fornecidas aos koalas. Esta informação poderá vir a ser útil para os veterinários e tratadores do Jardim Zoológico de Lisboa, permitindo a provisão diferenciada de alimento ao longo do ano e uma melhor gestão dos arboretos de onde provém o alimento dos koalas. Os animais sob estudo exibiram um nível médio de preferência superior para as espécies de eucalipto procedentes da Mata do Escaroupim, à exceção de E. maculata, E. occidentalis, E. perrianiana e E. rudis, que possuíram um nível de preferência superior quando foram originárias do Instituto Superior de Agronomia. Estas diferenças podem estar relacionadas com diferenças a nível genético entre as duas populações ou com a diferente idade das árvores dos dois locais. Os teores nutricionais das amostras de eucalipto analisadas foram similares aos referidos na literatura. Todas as amostras apresentaram níveis de azoto superiores ao limite mínimo para a manutenção de koalas referido na literatura. Os resultados deste trabalho estão em conformidade com as últimas descobertas, que sublinham a complexidade entre a ingestão, a palatabilidade e a composição química da folhagem na ecologia alimentar dos koalas.
ABSTRACT - The aim of his work was to study the feeding preferences of the koalas from the Zoo of Lisbon. First, a statistical analysis of the available data (between 2008 and 2012, recorded by the keepers) about the daily food preference level of the koalas was conducted, for different Eucalyptus species. Secondly, some “cafeteria trials” were performed to examine some aspects of the koalas’ food preferences and feeding behavior. Finally, nutritional content (dry matter, ash, fiber and protein) of 56 samples of Eucalyptus given to koalas was analyzed. The five animals under study have access to a very diverse diet (about 30 eucalyptus species), which allows a great level of selectivity. Statistical analysis indicated significant differences (P ≤ 0,05) between the food average preference levels of individual koalas, which may be related with physiological (age, sex, reproductive state) and/or sociological differences between them, and even with previous food experiences. Koalas showed a higher average level of preferences for some Eucalyptus species, like Eucalyptus botryoides, E. camaldulensis, E. globulus, E. macarthuri, E. occidentalis, E. ovata, E. polyanthemus, E. robusta and E. tereticornis. There was some variation of the average food preferences during the year. This information may become useful for keepers and veterinarians, allowing a differentiated feed supply during the year, as well as an optimization of the management of eucalyptus plantations. Koalas showed a higher average level of food preferences when the eucalyptus trees originated from Escaroupim forest, except for the species E. maculata, E. occidentalis, E. perrianiana and E. rudis, which showed a higher level of preferences when coming from Instituto Superior de Agronomia. These differences may be related to genetic and/or age differences between the tree populations of the places referred. The nutritional content of the eucalyptus samples was similar to that reported in the literature, when information about the eucalyptus species was available. Every sample presented greater nitrogen levels than the minimum threshold for koalas nutritional maintenance needs referred by Cork (1986). The results of this work are in accordance with the latest discoveries, which reveal the complexity in the interactions between ingestion, palatability and foliage composition in the koala food ecology.
7
Khan, Shahneaz Ali. "Development of a chlamydial vaccine for koalas (Phascolarctos cinereus)." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/97934/1/Shahneaz%20Ali_Khan_Thesis.pdf.
Abstract:
Widespread chlamydial infection in koalas resulting significant morbidity and mortality and is therefore a major threat for surviving koala density across Australia. Antibiotics are the currently practice one of the main therapeutic measures but the asymptomatic nature of the disease reduces their effectiveness. In this thesis, we evaluated the most updated version of rMOMP (major outer membrane protein) based anti-chlamydial vaccine adjuvanted with Tri-Adjuvant components. We have successfully completed our vaccine trial in captive koalas as well as in wild koalas. The vaccine induced specific immune responses and looks very promising to protect this iconic animals from debilitating effect of chlamydial infections.
8
Hey, Grace Valasi. "Identification of individual koalas : microsatellite analysis of faecal DNA." Thesis, View thesis, 2003. http://handle.uws.edu.au:8081/1959.7/451.
Abstract:
Current studies of koalas in the wild mainly rely on information gathered by traditional field methods, such as community sightings, spotlighting, radiotracking, animal trappings, ear tagging and faecal pellet incidence. Collection of faeces is potentially the most reliable source of non-invasively obtaining DNA samples, which can be used to identify specific individuals. This thesis demonstrated a simple, rapid and reproducible method of extracting DNA from Koala faecal pellets using a commercially available DNA extraction kit, shows the maximum age of pellets from which DNA can be reliably extracted and defines the conditions required for the long term storage of pellets before DNA extraction is carried out. Mitochondrial DNA PCR analysis provided a simple and rapid indication of the success of both the faecal DNA extraction and pellet collection process. The faecal DNA was successfully used for microsatellite analysis and the subsequent genetic profiling of individuals from within the Campbelltown Koala population. The study paves the way for the analysis of microsatellite loci in koala faecal pellet DAN to study populations, which are too sparsely distributed to allow the capture of individual koalas
9
Hey, Grace Valasi. "Identification of individual koalas : microsatellite analysis of faecal DNA /." View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20051220.110416/index.html.
10
Griffith, Joanna Elizabeth. "Studies into the diagnosis, treatment and management of chlamydiosis in koalas." Thesis, The University of Sydney, 2010. http://hdl.handle.net/2123/6836.
Abstract:
Koalas are an iconic Australian marsupial species that attract much public sympathy and support. Despite several thousand koalas being presented to wildlife rehabilitation facilities annually for treatment of traumatic injuries (primarily motor vehicle strikes and dog predation) and disease (principally chlamydiosis), little information exists regarding the success of treatments or whether rehabilitated animals survive in the wild after release. This thesis examines several aspects of the diagnosis, treatment and management of the most important infectious disease of koalas, chlamydiosis, and provides an evidence base for rational diagnostic and treatment decisions in the rehabilitation setting. Experimental work commences in Chapter 2 with a study of the admission records of a large koala rehabilitation facility (the Koala Hospital of the Koala Preservation Society of NSW) showing that traumatic presentations and those relating to clinical chlamydiosis were most common, with motor vehicle collisions apparently a significant and increasing threat to survival of the local koala population. The implications of these findings are discussed with reference to measures aimed at maintaining a viable population of wild koalas in Port Macquarie and for logistic planning at the Koala Hospital. Initial studies in this thesis confirmed that koalas with chlamydiosis are frequently treated at wildlife rehabilitation facilities. Despite the commonness of this disease, there is a lack of rigorous scientific studies examining frequently used treatments. Chapter 3, a retrospective review of medical records of a cohort of koalas admitted for treatment for chlamydiosis, revealed that diagnostic and treatment decisions were frequently based on clinical signs alone and treatment choices and durations were inconsistent with those used to successfully treat chlamydiosis in other species. Despite this, treated animals were frequently released and many survived in the wild. Chapter 4 outlines general methods common to the clinical work undertaken in Chapters 5, 7 and 9. Antibiotic treatment with drugs commonly used to treat chlamydiosis in other species (erythromycin, oxytetracycline) has led to wasting and death in koalas. A pilot study, presented in Chapter 5, found that, similarly, more modern forms of these drugs (doxycycline and azithromycin) cannot be used safely in koalas, leading to the author’s decision to investigate, in detail, the efficacy of the less conventional anti-chlamydial drugs, the fluoroquinolones. Studies of marsupial pharmacokinetics are uncommon and, prior to this thesis, there were no published studies of pharmacokinetics in koalas. The author’s investigations, using a modified agar diffusion assay (Chapter 6) and high performance liquid chromatography (Chapter 7), found the absorption of enrofloxacin and marbofloxacin by the oral route in koalas was extremely poor and suggested absorption rate limited disposition pharmacokinetics. In combination with plasma protein binding of approximately 50%, the concentrations of enrofloxacin and marbofloxacin achieved in plasma were not considered likely to inhibit the growth of chlamydial pathogens in vivo. In Chapter 8 the author explored the apparent contradiction between the failure to achieve appropriate plasma concentrations of fluoroquinolones to treat chlamydiosis and the apparent efficacy of these drugs reported in historical medical records. Methods to monitor clinical signs by clinical scoring and chlamydial load using real-time polymerase chain reaction were developed during the study. The results of these studies showed that clinical signs were poorly sensitive in determining the presence of chlamydial organisms in koalas; all fluoroquinolone treatment regimes led to a dramatic reduction in Chlamydophila pecorum load during treatment; and clinical signs improved in many animals. Importantly, however, pathogen load rebounded after withdrawal of treatment, indicating that most animals failed to clear infections. These findings have implications for the diagnosis, and treatment of chlamydial disease in koalas and for the subsequent return of fluoroquinolone treated animals to the wild. The findings and limitations of these studies are presented in general terms in Chapter 9 and recommendations for future studies are proposed.
11
Ramsay, Susan. "The ecology and dispersal patterns of juvenile koalas, phascolarctos cinereus, in fragmented habitat." Phd thesis, School of Biological Sciences, 1999. http://hdl.handle.net/2123/13892.
12
Ward, Steven John. "Koalas and the community : a study of low density populations in southern Sydney /." View thesis View thesis, 2002. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030331.112329/index.html.
Abstract:
Thesis (Ph.D.) -- University of Western Sydney, 2002."A thesis submitted to the University of Western Sydney in partial fulfillment of the requirements for the degree of Doctor of Philosophy" Bibliography: leaves 200-215.
13
Schmertmann, Laura. "The Cryptococcus gattii species complex in koalas: host-pathogen-environment interactions and molecular epidemiology." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20769.
Abstract:
The Cryptococcus gattii species complex comprises some of the aetiological agents of cryptococcosis, a severe fungal disease that affects a wide variety of hosts and is acquired from the environment by inhalation. Koalas (Phascolarctos cinereus) appear to be particularly susceptible to cryptococcosis. In Australia, eucalypt tree hollows are the classic ecological niche for C. gattii molecular type VGI and therefore are also a potential source of infection. Aspects of the tree hollow microenvironment that may allow for the growth and dispersal of C. gattii VGI remain poorly understood. The C. gattii species complex has been associated with outbreaks and case clusters, and animals are often considered useful sentinels for the disease in these scenarios. The prevalence of cryptococcosis in Australian wildlife remains unknown. Given the koala’s propensity towards developing cryptococcosis, and its regular contact with a common ecological niche for the C. gattii species complex (eucalypts), it is an ideal sentinel species. The host-pathogen-environment interactions of cryptococcosis caused by the C. gattii species complex, particularly progression from exposure to colonisation of the respiratory mucosa to eventual tissue invasion, remain poorly understood. This thesis uses amplicon-based next generation sequencing to characterise the fungal microbiome of Australian tree hollows, focusing on the role that the C. gattii species complex may play in this microenvironment. The prevalence of cryptococcosis in a population of free-ranging koalas is systematically characterised, while the pathogenesis, treatment and diagnosis of the disease in this host species are also explored. Finally, fine-scale molecular epidemiology tools (multi-locus sequence typing and whole genome sequencing) are used to determine sources of infection and examine disease caused by the C. gattii species complex in Australia, using primarily the koala as a model for naturally-occurring cryptococcosis.
14
Black, Lisa Ann. "Aspects of the pharmacokinetics and pharmacodynamics of chloramphenicol, enrofloxacin and fluconazole in koalas (Phascolarctos cinereus)." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/11597.
Abstract:
In Australia, thousands of koalas receive medical treatment annually, mostly due to trauma and disease. The most common disease affecting koalas is chlamydiosis, responsible for debilitating conjunctivitis and urogenital disease. Cryptococcosis occurs less commonly, and is often fatal. Information regarding the pharmacokinetics and pharmacodynamics of commonly used drugs in koalas is lacking. The information available indicates koalas may have highly developed barriers to oral drug absorption, and an ability to rapidly metabolise and eliminate drugs following administration; these mechanisms probably evolved due to the koala’s highly toxic Eucalyptus spp. diet. The pharmacokinetics of chloramphenicol and enrofloxacin are investigated, and in vitro susceptibility testing of these drugs against koala isolates of Chlamydia pecorum is undertaken. Chloramphenicol and enrofloxacin are eliminated at similar rates to other mammals. Chloramphenicol is found to be a potential treatment option for koala chlamydiosis, although slight dosage adjustments may be necessary. Enrofloxacin is found to be unsuitable for treating chlamydiosis in koalas. It may, however, be useful in treating other bacterial infections. The pharmacokinetics of fluconazole as a treatment option for cryptococcosis are also investigated. Findings include poor and variable oral absorption, rapid elimination, and absorption rate-limited disposition following oral administration; these findings contrast the pharmacokinetics of fluconazole in other species. Fluconazole is unlikely to be successful in treating cryptococcosis at currently used dosages. When the findings presented in this thesis are viewed within the context of the metabolic pathways of these drugs in other species, hypotheses regarding the capacity of these metabolic pathways in koalas can be formed, and speculation can be made regarding the types of drugs that are likely to display favourable pharmacokinetic profiles in koalas.
15
Marschner, Caroline. "Xenobiotics and the effects of eucalypt monoterpenes on the cytokine expression of koalas, Phascolarctos cinereus." Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/21697.
Abstract:
The koala is a specialist herbivore thriving on a diet of mainly eucalypts, which contain a toxic cocktail of highly absorbable monoterpenes that can affect health in various ways when ingested in high amounts. Specialist adaptations are required to protect animals from acute intoxication. Koalas apply amongst other strategies high metabolic detoxification capacities to deal with these components but increased exposure to anthropogenic environmental contamination is potentially effecting metabolic detoxification pathways and therefore can reduce food intake in this species. The aim of this thesis is to investigate the systemic exposure of koalas to a range of xenobiotics. The profile of main eucalypt monoterpenes in the ingesta of deceased koalas was investigated and tested for consistencies between animals and regions. A well-balanced monoterpene profile was found when mean profiles of different regions were compared. Blood exposure to selected monoterpenes was found continuous but low compared to other eucalypt feeders. Monoterpene profile in blood was similar to that in ingesta of koalas (but different to the profile of lymphatic tissue) suggesting a feeding behavior that balances toxin exposure in peripheral blood. Accumulation of frequently used pesticides, metal and trace elements were further investigated in koalas from different regions of NSW and Victoria. Hepatic accumulation of pesticides is uncommon in this species, but element exposure of koalas changes significantly with land use and region and less commonly with age and sex of the animals. This study also provides first insight into the effects of eucalypt monoterpenes on the immune function of this species. This study demonstrates that circulating concentrations of monoterpenes have dose dependent inhibitory effects (in vitro) on cytokine expression of koala peripheral blood mononuclear cells, suggesting a potential evolutionary adaptation in this species.
16
Logan, Murray. "Nutritional stresses and the feeding behaviour and activity patterns of free-ranging koalas (Phascolarctos cinereus : Goldfuss)." Monash University, School of Biological Sciences, 2003. http://arrow.monash.edu.au/hdl/1959.1/9593.
17
Santamaria, Flavia. "Outcomes and implications of a koala translocation in the Ballarat region." Thesis, University of Ballarat, 2002. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/58351.
18
Santamaria, Flavia. "Outcomes and implications of a koala translocation in the Ballarat region." University of Ballarat, 2002. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/15201.
19
Budd, Christie. "A pharmacokinetic investigation of florfenicol as an alternate treatment for chlamydiosis in the koala (Phascolarctos cinereus)." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14633.
Abstract:
Florfenicol (FFC) as Nuflor™ was investigated as a treatment of chlamydiosis in koalas. Chlamydiosis is considered the important infectious disease of koalas, causing significant morbidity and mortality. A HPLC-UV assay of FFC in koala plasma was developed with a lower limit of quantification (LLOQ) of 0.3 µg/mL. Florfenicol was administered at 20 mg/kg subcutaneously (SC) once (n=3), 10 mg/kg intravenously (IV) once (n=3) and 5 mg/kg IV every 48 hours thrice (n=3). Plasma FFC concentrations were compared with minimum inhibitory concentrations of FFC against Chlamydia pecorum in vitro. The clinical records and outcomes of 19 wild koalas treated with FFC are reviewed and presented in summary. The mean (n=3) maximum concentration of FFC in plasma (Cmax) following 20 mg/kg SC was 1.2 μg/ml at Tmax of 4 hours, with concentrations < LLOQ by 24 hours. Following IV administration at 10 mg/kg, FFC was noted to persist at potentially useful concentrations in plasma for a practical dosing interval in 2/3 koalas with a mean, (n= 3) FFC plasma concentration of 19 μg/mL at 24 hours. A prolonged terminal elimination phase appears to exist following intravenous administration. The proportion of FFC binding to koala plasma proteins in vitro is 13%. Florfenicol was poorly tolerated by koalas following administration of multiple subcutaneous dosages from 5 – 20 mg/kg. Koalas were tolerant of single FFC treatments of 20 mg/kg SC, 10 mg/kg IV and three consecutive dosages of 5 mg/kg IV. A single intravenous dosage of FFC at 10 mg/kg may be useful to assist control of some bacterial infections, however caution is recommended if administering Nuflor™ to koalas via this route. Florfenicol cannot be recommended as an alternative to chloramphenicol for the treatment of chlamydiosis in koalas.
20
Bryan, Brett. "The ecological, psychological and political issues surrounding the management of koalas in southern Mt Lofty Ranges /." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09ENV/09envb915.pdf.
Abstract:
Thesis (M. Env. Sc.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1996.Two col. maps in pocket on back end-paper. Includes bibliographical references (leaves 118-135).
21
Kimble, Benjamin. "Pharmacokinetic aspects of meloxicam in koalas: including its hepatic microsomal metabolism compared with other selected species." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13996.
Abstract:
Prior to this research, no disposition studies of meloxicam (nor any other non steroidal anti-inflammatory drugs) had been conducted in koalas (a specialist Eucalyptus spp. foliage feeder) despite being readily administered to this species, in the field. Thus, aspects of the in-vivo pharmacokinetic profile of meloxicam in the koala and the in-vitro metabolism of meloxicam in the koala and selected species were investigated. In the first stage of the research, a simple, sensitive and improved method using high performance liquid chromatography equipped with photo diode array detection was developed and validated to determine meloxicam concentrations in koala plasma, applicable for in-vivo pharmacokinetic study. Following intravenous injection, meloxicam exhibited a rapid plasma clearance of 0.44 ± 0.20 L/h/kg in koalas (n = 5). Median plasma terminal elimination t1/2 was 1.19 h (range 0.71 to 1.62 h). In koalas, bioavailability after the subcutaneous injection was approximately 56 to 70 % where oral bioavailability was negligible. Plasma protein binding of meloxicam was about 98%. Three hydroxylated metabolites of meloxicam (M1, M2 and M3) were detected in the koala plasma with one (M1) identified as the 5-hydroxy methyl metabolite. According to the in-vitro hepatic microsomal metabolism of meloxicam, it was demonstrated that biotransformation of meloxicam, likely mediated via cytochrome P450 enzymes, were much faster in koalas (and also in other Eucalyptus spp. foliage feeders: ringtail possums and brushtail possums) compared to rats or dogs. The rank order of apparent in-vitro intrinsic clearance was brushtail possums (n = 3) (mean: 394 μL/min/mg protein) > koalas (n = 6) (50 μL/min/mg protein) > ringtail possums (n = 2) (36 μL/min/mg protein) (with no significant difference between koalas and ringtail possums) > pooled rats (3.2 μL/min/mg protein) > pooled dogs (not determined as the rate of metabolism was too slow). According to the in-vitro study, single hydroxylated metabolite (M1) was determined as the major product of meloxicam in brushtail possums and the rat whereas multiple hydroxylated metabolites were observed in the koala (M1, M2, and M3) and the ringtail possum (M1 and M3). Using a well-stirred model, this research showed applicability of predicting in-vivo clearance of meloxicam in koalas and the rat from the apparent in-vitro intrinsic clearance data (average fold error for prediction was less than 2). While cytochrome P4502C9 is the major responsible enzymes for metabolism of meloxicam, the research also found that the stability of other cytochrome P4502C9 substrates, particularly non steroidal anti-inflammatory drugs were also generally not stable in hepatic microsomes of koala and other Eucalyptus.spp foliage feeders than the rat. Particularly, there was some similarity on the pattern of CYP2C9 substrates stabilities between koala and ringtail possum (Eucalyptus spp. foliage specialist feeders). This research demonstrated that koalas exhibited rapid plasma clearance and extremely poor oral bioavailability of meloxicam compared with other eutherian species. Due to differences in the rate of hepatic metabolism on meloxicam, other eutherians such as rats or dogs are inadequate model for dosage extrapolation of this drug in koalas. Furthermore, as catalytic activity of cytochrome P4502C-like enzymes appeared to be different in these Eucalyptus spp. foliage feeders, it is highly recommended to consider when extrapolating dosage of therapeutic drugs (cytochrome P4502C9 substrates), particularly non steroidal anti-inflammatory drugs, from other eutherians. On the other hand, as in-vivo clearance is one of the pharmacokinetic indexes for determining the dosage of drug, this study demonstrates the utility of in-vitro to in-vivo scaling as an alternative prediction method of drug clearance in koalas.
22
van, der Mensbrugghe-Ingles Joelle, and n/a. "Kangaroos, koalas and business tycoons : Australia and Australians in the western European press, October 1994-March 1995." University of Canberra. Communication, Media & Tourism, 1996. http://erl.canberra.edu.au./public/adt-AUC20061109.164721.
Abstract:
This research looks at the way Australia is portrayed in the Western
European press, particularly in the light of Australia's recent emphasis on
being a clever country, within the Asia Pacific region.
The research is based on a quantitative and qualitative analysis of all articles
explicitly referring to Australia, in seven newspapers from Belgium (2),
France (2), Germany (1) and the United Kingdom (2), over a 6 month period.
The main hypothesis was that those newspapers without Australian based
correspondents or stringers picture Australia in a stereotypical way and that
"news" in those papers, instead of giving "news", reinforces existing ideas
and images held of Australia. My research supports the hypothesis, but also
uncovers the very important role played by editors at home. They decide
what is important, what is news and their choice will go to consonant
"news".
The research shows that newspapers in Europe largely portray Australia's
older images, with its kangaroos, koalas and beaches peopled by sportsmen.
Australia is largely portrayed as an almost untouched country inhabited by
animals to be found nowhere else, and by people (mainly white Anglo-
Saxon males) reputed for their friendliness, as well as for their laziness and
sometimes their strangeness. "Newer" images of Australia promoted by the
Australian government (e.g. Australia as a clever country and part of the
Asia-Pacific region) get relatively little coverage in the Western European
press.
23
Stiles, James W. "From chameleons to koalas exploring Australian culture with pre-service teachers through children's literture and international experience /." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1086105676.
Abstract:
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xi, 279 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Barbara Lehman, College of Education. Includes bibliographical references (p. 241-255).
24
Mangar, Chandan. "Characterisation of lymphocytes and cytokines in healthy and diseased koalas (Phascolarctos cinereus) using cell-type-specific monoclonal antibodies." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/123896/1/Chandan_Mangar_Thesis.pdf.
Abstract:
This thesis is a step forward in developing scientific tools and methods to study the koala (Phascolarctos cinereus) immune system in health and disease. Koala numbers are declining for multiple reasons, the most significant of which is infectious disease. The antibodies developed from this thesis have been successfully used to identify cell populations that play key roles in the host immune system. Furthermore, the antibody 'toolbox' developed in this thesis can now be used to monitor population health, develop prognostic indicators, evaluate vaccine studies and increase our understanding of comparative immunology.
25
Cui, Jian. "Variation of the Toll-like receptors in two marsupial species, Tasmanian devils, Sarcophilus harrisii, and Koalas, Phascolarctos cinereus." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14061.
Abstract:
Genetic diversity plays an important role in wildlife conservation, particularly genetic diversity in immune genes, as some genetic variants are able to contribute to disease resistance and susceptibility. Low genetic diversity often occurs in endangered species and low genetic diversity in key immune genes can lead to higher disease susceptibility. To maximise the chance of protecting endangered species, it is possible to study and then manage genetic diversity in immune genes. One of the key gene families involved in adaptive immunity is the Major Histocompatibility Complex (MHC) and numerous studies have described a relationship between MHC alleles and susceptibility to certain diseases. Another family involved in innate immunity are the Toll-like receptors (TLRs) and in this thesis I have measured genetic diversity at TLRs in two iconic Australian marsupials, the Tasmanian devil and the koala, in order to better inform management practices. The Tasmanian devil is endangered due to the emergence of a new transmissible cancer called Devil Facial Tumour Disease (DFTD). Low genetic diversity has been found across the devil genome, including at neutral markers and the MHC genes. In order to protect the devil from extinction, an insurance population has been established and the primary purpose of this programme is to capture all genetic diversity in devils and to protect this diversity over time. In the first section of this thesis I characterise the TLR genes in the devil and then measure the TLR diversity in wild devil populations. Ten TLR genes were identified in the devil transcriptome sequence database and low levels of diversity were found in 25 devils from across Tasmania. TLR2, TLR3 and TLR1/6like have two alleles and the other seven TLRs are monomorphic. A study of the polymorphic TLR genes in another 50 devils from the insurance populations was conducted and the same variants found. This indicates that the insurance population has captured all known variants at TLRs. The TLRs are important genes for pathogen resistance and previous studies have described a correlation between TLR variants and Chlamydia susceptibility in humans. Chlamydia is having significant impacts on koala populations and our knowledge of koala innate immunity is still limited. The second part of the thesis focuses on the characterisation of TLRs in the koala in order to provide a measure of geneticdiversity at TLRs. We found nine TLRs in the koala immune tissue transcriptome and one TLR from a draft sequence of the koala genome. We surveyed genetic diversity in 20 koalas from New South Wales, Australia and found that TLR10 is monomorphic and the other nine TLRs have between two and twelve alleles. Measuring TLR diversity in these two species provides a springboard to future studies on innate immunity in the marsupials.
26
Tokonami, Fumie. "Pharmacokinetic profile of fentanyl in the plasma of koalas (Phascolarctos cinereus) – after a single intravenous bolus and when applied as a transdermal patch." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23242.
Abstract:
The aim of this study was to describe the pharmacokinetic (PK) profile of fentanyl citrate after a single intravenous (i.v.) bolus and transdermal fentanyl patch (TFP) administration to the koala. An analytical method that can reliably detect a fentanyl concentration less than 1 ng/mL in koala plasma was required as several PK studies in humans and domestic animals suggested a minimum plasma fentanyl concentration greater than 1 ng/mL to provide analgesia. Preliminary study into development and validation of a high-performance liquid chromatography method for the determination of fentanyl concentration in koala plasma failed to detect fentanyl concentrations lower than 100 ng/mL. A commercially available fentanyl enzyme-linked immunosorbent assay (ELISA) kit designed for use with human biological specimens was validated to be a sensitive and reliable method for detection of fentanyl in koala plasma for the purpose of this study. Fentanyl citrate was administered intravenously at 5 μg/kg as a single injection to 5 koalas. TFPs that delivered fentanyl at 25 μg/h were applied to the skin of two koalas. Maximum plasma concentration (Cmax) of fentanyl was 1.84 ± 0.39 ng/mL after i.v. administration, clearance was 68.1 ± 34.9 mL/kg/h, volume of distribution was 2.55 ± 0.99 L/kg and elimination half-life was 0.60 ± 0.2 h. Calculated constant infusion rate was 1.91 to 3.64 μg/kg/h. After application of TFP, plasma fentanyl concentration was first detected at 4 h in a koala and 8 h in the other koala. Mean Cmax of 0.89 ng/mL (range 0.84 – 0.94 ng/mL) was detected at 73 – 74 h, 1-2 h after patch removal. The TFP appears to provide relatively constant plasma concentration of fentanyl between 24 h from the time of application to patch removal at 72 h in koalas.
27
Krockenberger, Andrew Karl. "Energetics and nutrition during lactation in the koala, Phascolarctos cinereus : how does an arboreal folivore meet its energy requirements for reproduction?" Thesis, The University of Sydney, 1993. http://hdl.handle.net/2123/15833.
28
Dique, David S. "The distribution, abundance and dynamics of a regional koala population in south-east Queensland /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17880.pdf.
29
Fowler, Elizabeth Victoria. "Genetic analysis of the koala (Phascolarctos cinerus)." Thesis, Queensland University of Technology, 1999.
30
Wilkinson, Ray. "Characterisation of the immune responses of the koala /." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phw687.pdf.
31
Estevam, Deborah Maria de Paula. "Sporobolomyces koalae como um novo agente de controle biológico /." Jaboticabal, 2019. http://hdl.handle.net/11449/183202.
Abstract:
Orientador: Katia Cristina KupperCoorientador: Maurício Ventura Mazzi
Fernando Russo Costa do Bomfim
Rita de Cássia Panizzi
Resumo: Dentre as doenças de pós-colheita que ocorrem em citros, encontra-se a podridão azeda, causada por Geotrichum citri-aurantii, que afeta frutos de todas as espécies e cultivares em países produtores da cultura. Para as condições de Brasil, não existem fungicidas registrados para o controle desse patógeno. Na busca de uma alternativa de manejo, esse trabalho visa dar continuidade aos estudos da levedura Sporobolomyces koalae, que em pesquisas anteriores mostrou potencial para o controle da doença, tendo como objetivos específicos: (i) a análise filogenética para confirmação da espécie do isolado ACBL-42 (Sporobolomyces koalae); (ii) verificar o efeito de diferentes meios de cultivo na produção de células da levedura; (iii) determinar a curva de crescimento de S. koalae; (iv) verificar o efeito de fontes nutricionais no cultivo da levedura para a atividade antagônica; (v) verificar mecanismos de ação da levedura que possam estar envolvidos no controle de G. citri-aurantii, e, finalmente, (vi) dar início a estudos de biossegurança do antagonista, visando a produção futura de um bioproduto. A partir dos resultados apresentados neste estudo, foi possível concluir que a região ITS foi suficiente para confirmar a espécie, porém a utilização das duas regiões (ITS e D1/D2) para a construção de uma árvore multilocus aumentou a precisão quanto a distinção entre os isolados da mesma espécie; o melhor meio de cultura para o crescimento de S. koalae foi o Sabouraud, que quando suplementado ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Among the post-harvest diseases that occur in citrus, there is the sour rot, caused by Geotrichum citri-aurantii, which affects fruits of all species in crop-producing countries. There are no fungicides registered for control in Brazil. This work aims to continue the studies of the yeast Sporobolomyces koalae, which in previous studies showed potential to control the disease, having as specific objectives: (i) phylogenetic analysis for confirmation of species for ACBL-42 (Sporobolomyces koalae); (ii) verify the effect of different culture media on production of yeast cells; (iii) determine growth curve of S. koalae; (iv) verify the effect of nutritional sources in the culture media for the antagonistic activity; (v) verify mechanisms of action that may be involved in the control of G. citri-aurantii, (vi) to initiate the biosafety studies of the antagonist, aiming a future production of a bio-product. From the results presented in this study, it was possible to conclude that the ITS region was sufficient to confirm species, but the use of two regions (ITS and D1/D2) for the construction of a multilocus tree increased the precision regarding the distinction among isolates of the same species; the best culture medium for S. koalae was Sabouraud, which when supplemented with 1% sucrose or 0.05mM copper sulfate, was able to favor biofilm production and antagonism; there is no production of siderophores and, finally, S. koalae does not present proinflammatory effects in tests of c... (Complete abstract click electronic access below)
Mestre
32
Higgins, Damien. "Chlamydial Disease of the Koala: A Study of Pathogenesis and Host Response." Thesis, The University of Sydney, 2004. https://hdl.handle.net/2123/25063.
Abstract:
Chlamydial infection occurs commonly in koalas (Phascolarctos cinereus) and, as in humans, can cause proliferative conjunctivitis and disease of the urinary and reproductive tracts. Past studies suggest that increased expression of chlamydial disease in koalas is associated with habitats disturbed by humans, but the mechanisms and specific factors influencing susceptibility of koalas to disease have not been studied in detail. This thesis aims to further the goal of describing pathogenic mechanisms and the host-pathogen-environment interaction for chlamydial disease in koalas by developing techniques to begin exploring in koalas some of the concepts that are central to our understanding of this condition in humans. These concepts include the role of T helper 1 (Thl)/ T helper 2 (Th2) lymphocyte balance and interferon gamma, and the association of reproductive tract fibrosis and infertility with serological responses to chlamydial heat shock proteins.
33
Binns, Jack. "Development of high-pressure single-crystal neutron diffraction on KOALA." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20416.
Abstract:
This thesis project has focused on the development of high-pressure single-crystal diffraction experiments on the neutron Laue diffractometer KOALA at the OPAL reactor at ANSTO, Australia. Over the course of this project several candidate systems have been studied under conditions of high-pressure using X-ray diffraction with a view to their use in developmental experiments on KOALA. The results of two high-pressure KOALA experiments are presented as well as the notable results from X-ray diffraction on the candidate systems. The first experiment on hexamethylenetetramine provided valuable insights into how reduced crystallite size and reciprocal-space access affects data collected on KOALA. In addition, data treatment techniques were developed to deal with the unique and challenging high-pressure Laue data, including corrections for attenuation due to the cell body. The ability to collect data through the body of cell prompted a further experiment on the complex, low-symmetry structure of the amino acid l-arginine dihydrate. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamethylenetetramine with bond lengths and angles that agree with literature data within experimental error. This technique is highly suited to low-symmetry crystals, as shown by the successful refinement of data from a l-arginine dihydrate crystal. In such cases the transmission of diffracted beams results in higher completeness values than are possible with X-rays. The hydrogen-bonded ferroelectric rubidium hydrogensulfate was the subject of ambient-pressure experiments on KOALA investigating the nature of the ferroelectric transition. Further high-pressure X-ray diffraction studies were carried out to resolve the structures of phases at high-pressure and to investigate the ferroelectric transition under pressure. The potassium cobalt citrate metal-organic framework UTSA-16 has shown a wide variety of pressure-mediated framework-solvent interactions including negative linear compressibility, the ordering of potassium ions, and coordination changes which were investigated by high-pressure single-crystal and powder X-ray diffraction. These behaviors are rationalised by examination of the structural changes occurring in the framework under pressure. Two members of the widely studied alkylammonium tetrachlorometallate family, tetramethylammonium tetrachloroferrate(III) and tetramethylammonium tetrachlorogallate(III), display numerous phase transitions with temperature. The structures of these phases have been determined for the first time, and the contrast between the two materials explored with first-principles calculations.
34
Sanchioni, Marco. "Prototipizzazione di cappa disinquinante per applicazioni ospedaliere con tecnologia koala." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8092/.
Abstract:
Le infezioni ospedaliere (o nosocomiali) sono le complicanze più frequenti e gravi nell’ambito dell’assistenza sanitaria, e costituiscono una delle maggiori cause di morbilità e mortalità. Tale denominazione comprende un insieme piuttosto eterogeneo di condizioni diverse sotto il profilo sia microbiologico che epidemiologico, ma accomunate dall’elevato impatto sulla salute dei pazienti e sui costi sanitari.
Molti fattori contribuiscono a condizionare la frequenza delle infezioni nosocomiali, tra cui la compromissione delle difese immunitarie dei pazienti, l’invasività delle nuove tecnologie e pratiche sanitarie in campo diagnostico/terapeutico, l’esecuzione di procedure assistenziali nel non rispetto delle norme igieniche da parte degli operatori sanitari, l’utilizzo estensivo degli antibiotici con conseguente insorgenza di ceppi batterici resistenti; per ultimo, non a caso, l’inquinamento dell’ambiente ospedaliero.
Ad oggi, infatti, la contaminazione microbica dell’ambiente (aria e superfici) è ritenuto un fattore di rischio secondario, rispetto alla correttezza dei comportamenti degli operatori (rispetto delle procedure di asepsi, delle precauzioni di isolamento, adeguate tecniche operatorie, ecc), per la quale si sono concentrati gran parte degli sforzi in materia di prevenzione. Ciò probabilmente è anche dovuto al fatto che finora nessuna tecnologia è stata in grado di intervenire in maniera adeguata sulla decontaminazione microbica di aria e superfici.
I dati allarmanti sulle infezioni ospedaliere a livello mondiale sono la prova che le misure adottate finora per contrastare il problema non sono sufficienti; inoltre il monito lanciato dall’Organizzazione Mondiale della Sanità riguardo alla progressiva perdita d’efficacia delle terapie antibiotiche impone di trovare al più presto nuove armi per la lotta alle infezioni.
Una via sperimentale e innovativa, volta alla riduzione della frequenza d’infezioni ospedaliere, potrebbe essere proprio il disinquinamento dell’aria indoor negli ambienti ospedalieri e delle superfici a contatto diretto con il paziente, ottenibile per mezzo di una tecnologia ad hoc: la “Tecnologia Nano-Safe Koala®” (brevettata da D.A.TECH., azienda specializzata nel disinquinamento dell’aria indoor).
Per l’applicazione di tale tecnologia in ambito ospedaliero è stata progettata una "cappa disinquinante", pensata per essere installata al di sopra del posto letto, al fine di fornire al paziente aria incontaminata e di sanificare le superfici a contatto con esso.
Una volta realizzato il prototipo, sono state condotte delle sperimentazioni per testarne l’efficacia e l’efficienza, per mezzo di strumenti specifici per quanto riguarda l’analisi dell’aria, e con test biologici per quanto riguarda l’analisi delle superfici.
35
Mitchell, Candice Melissa. "Morphologic and genomic characterisation of the koala Chlamydia pneumoniae strain." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/33259/1/Candice_Mitchell_Thesis.pdf.
Abstract:
Chlamydia pneumoniae is a common human and animal pathogen associated with a wide range of upper and lower respiratory tract infections. In more recent years there has been increasing evidence to suggest a link between C. pneumoniae and chronic diseases in humans, including atherosclerosis, stroke and Alzheimer’s disease. C. pneumoniae human strains show little genetic variation, indicating that the human-derived strain originated from a common ancestor in the recent past. Despite extensive information on the genetics and morphology processes of the human strain, knowledge concerning many other hosts (including marsupials, amphibians, reptiles and equines) remains virtually unexplored. The koala (Phascolarctos cinereus) is a native Australian marsupial under threat due to habitat loss, predation and disease. Koalas are very susceptible to chlamydial infections, most commonly affecting the conjunctiva, urogenital tract and/or respiratory tract. To address this gap in the literature, the present study (i) provides a detailed description of the morphologic and genomic architecture of the C. pneumoniae koala (and human) strain, and shows that the koala strain is microscopically, developmentally and genetically distinct from the C. pneumoniae human strain, and (ii) examines the genetic relationship of geographically diverse C. pneumoniae isolates from human, marsupial, amphibian, reptilian and equine hosts, and identifies two distinct lineages that have arisen from animal-to-human cross species transmissions. Chapter One of this thesis explores the scientific problem and aims of this study, while Chapter Two provides a detailed literature review of the background in this field of work. Chapter Three, the first results chapter, describes the morphology and developmental stages of C. pneumoniae koala isolate LPCoLN, as revealed by fluorescence and transmission electron microscopy. The profile of this isolate, when cultured in HEp-2 human epithelial cells, was quite different to the human AR39 isolate. Koala LPCoLN inclusions were larger; the elementary bodies did not have the characteristic pear-shaped appearance, and the developmental cycle was completed within a shorter period of time (as confirmed by quantitative real-time PCR). These in vitro findings might reflect biological differences between koala LPCoLN and human AR39 in vivo. Chapter Four describes the complete genome sequence of the koala respiratory pathogen, C. pneumoniae LPCoLN. This is the first animal isolate of C. pneumoniae to be fully-sequenced. The genome sequence provides new insights into genomic ‘plasticity’ (organisation), evolution and biology of koala LPCoLN, relative to four complete C. pneumoniae human genomes (AR39, CWL029, J138 and TW183). Koala LPCoLN contains a plasmid that is not shared with any of the human isolates, there is evidence of gene loss in nucleotide salvage pathways, and there are 10 hot spot genomic regions of variation that were previously not identified in the C. pneumoniae human genomes. Sequence (partial-length) from a second, independent, wild koala isolate (EBB) at several gene loci confirmed that the koala LPCoLN isolate was representative of a koala C. pneumoniae strain. The combined sequence data provides evidence that the C. pneumoniae animal (koala LPCoLN) genome is ancestral to the C. pneumoniae human genomes and that human infections may have originated from zoonotic infections. Chapter Five examines key genome components of the five C. pneumoniae genomes in more detail. This analysis reveals genomic features that are shared by and/or contribute to the broad ecological adaptability and evolution of C. pneumoniae. This analysis resulted in the identification of 65 gene sequences for further analysis of intraspecific variation, and revealed some interesting differences, including fragmentation, truncation and gene decay (loss of redundant ancestral traits). This study provides valuable insights into metabolic diversity, adaptation and evolution of C. pneumoniae. Chapter Six utilises a subset of 23 target genes identified from the previous genomic comparisons and makes a significant contribution to our understanding of genetic variability among C. pneumoniae human (11) and animal (6 amphibian, 5 reptilian, 1 equine and 7 marsupial hosts) isolates. It has been shown that the animal isolates are genetically diverse, unlike the human isolates that are virtually clonal. More convincing evidence that C. pneumoniae originated in animals and recently (in the last few hundred thousand years) crossed host species to infect humans is provided in this study. It is proposed that two animal-to-human cross species events have occurred in the context of the results, one evident by the nearly clonal human genotype circulating in the world today, and the other by a more animal-like genotype apparent in Indigenous Australians. Taken together, these data indicate that the C. pneumoniae koala LPCoLN isolate has morphologic and genomic characteristics that are distinct from the human isolates. These differences may affect the survival and activity of the C. pneumoniae koala pathogen in its natural host, in vivo. This study, by utilising the genetic diversity of C. pneumoniae, identified new genetic markers for distinguishing human and animal isolates. However, not all C. pneumoniae isolates were genetically diverse; in fact, several isolates were highly conserved, if not identical in sequence (i.e. Australian marsupials) emphasising that at some stage in the evolution of this pathogen, there has been an adaptation/s to a particular host, providing some stability in the genome. The outcomes of this study by experimental and bioinformatic approaches have significantly enhanced our knowledge of the biology of this pathogen and will advance opportunities for the investigation of novel vaccine targets, antimicrobial therapy, or blocking of pathogenic pathways.
36
Ferraz, Luriany Pompeo. "Detecção, caracterização e purificação parcial de toxina killer produzida por Sporobolomyces koalae /." Jaboticabal, 2018. http://hdl.handle.net/11449/153927.
Abstract:
Orientador: Kátia Cristina KupperCoorientador: Maurício Ventura Mazzi
Banca: Taicia Pacheco Fill
Banca: Maria Fátima das Graças Fernandes da Silva
Banca: João Martins Pizauro Junior
Banca: Eliana Gertrudes de Macedo Lemos
Resumo: O fenômeno killler é característico de leveduras que produzem e excretam proteínas ou glicoproteínas que são inibidoras de células microbianas sensíveis. A estabilidade e atividade das toxinas killer são altamente sensíveis a fatores como pH, temperatura de incubação das leveduras, composição e propriedades físico-químicas do meio e concentração de células sensíveis. Sporobolomyces koalae é uma nova espécie de levedura com potencial para produção de toxina killer. No intuito de se conhecer mais sobre as funções desse microrganismo no ecossistema, esse trabalho teve por objetivos: (i) detectar a atividade killer do precipitado proteico de S. koalae, (ii) caracterizar bioquimicamente e funcionalmente o precipitado proteico S. koalae, (iii) purificar parcialmente a toxina killer produzida por S. koalae e, finalmente, (iv) verificar sua ação antagônica sobre Geotrichum citri-aurantii e Penicillium digitatum, patógenos que ocorrem na póscolheita de citros. Pelos resultados obtidos neste trabalho, foi possível detectar a presença de atividade killer no precipitado proteico da levedura S. koalae contra células sensíveis da levedura Saccharomyces cerevisiae NCYC 1006. O precipitado proteico da levedura apresenta várias proteínas com diferentes tamanhos moleculares e, parte dessas proteínas é positiva para atividade de β1,3-glucanase, quitinase e protease, podendo ser uma dessas enzimas ou, o sinergismo entre elas, o responsável pelo fator killer da levedura. A funcionalidade de suas ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The killer phenomenon is characterized by yeasts that produce and excrete proteins or glycoproteins that are inhibitors of sensitive microbial cells. The stability and activity of killer toxins are highly sensitive to the factors such as pH, the temperature of incubation of yeasts, composition and physical-chemical properties of the medium and concentration of sensitive cells. Sporobolomyces koalae is a new species of yeast with potential for killer toxin production. In order to know more about the functions of this microorganism in the ecosystem, this work had as objectives: (i) to detect the killer activity of the S. koalae protein precipitate, (ii) to characterize biochemically and functionally the S. koalae protein precipitate, (iii) to partially purify the killer toxin produced by S. koalae, and, finally, (iv) to verify its antagonistic action on Geotrichum citri-aurantii and Penicillium digitatum, pathogens that occur in the postharvest of citrus. By the results obtained in this work, it was possible to detect the presence of killer activity in the protein precipitate of S. koalae against sensitive cells of Saccharomyces cerevisiae NCYC 1006. The protein precipitate from yeast has several proteins with different molecular sizes and some of these proteins are positive for β1,3-glucanase, chitinase and protease activity. It may be one of these enzymes or synergism between them, the responsible for the killer factor. The functionality of their proteins for killer activity ... (Complete abstract click electronic access below)
Doutor
37
Shojima, Takayuki. "Construction and characterization of an infectious molecular clone of koala retrovirus." Kyoto University, 2013. http://hdl.handle.net/2433/179348.
38
Connolly, Joanne H. "Immunopathological characterisation of infectious diseases of the koala and the platypus." Thesis, The University of Sydney, 2000. http://hdl.handle.net/2123/8428.
Abstract:
This study characterised the pathological and immunopathological features of selected infectious diseases in the koala and the platypus. Originally, lymphosarcoma, cryptococcosis and chlamydiosis in the koala were chosen. Lymphosarcoma was included because of the putative retroviral involvement. Another infectious disease of Australian wildlife, mucormycosis of the platypus, was also included in the study. One hundred and ten koalas were necropsied throughout the study to determine the main cause of death, other pathological conditions present and to provide a source of case material. Fifty-six koala lymphoid neoplasia cases were obtained and the clinical features and clinical pathology were described. Cases were classified according to the tissues affected and the morphology of the neoplastic cells. The technique of immunohistochemistry was successfully applied to immunophenotype koala lymphoid neoplasms. Approximately half the cases were of the T cell immunophenotype, one quarter of B cell immunophenotype and one quarter did not stain. Multiple organ involvement and/or lymphoid leukaemia were common, probably reflecting presentation of koalas at advanced stages of disease. In order to improve understanding of the dynamics of progression from asymptomatic carriage of Cryptococcus neoformans to cryptococcosis, a preliminary study was undertaken to determine the prevalence, extent, biotype and seasonality of nasal and skin colonisation in the koala by Cryptococcus neoformans. Over a 22-month period, sequential nasal and skin swabs were obtained from 52 healthy captive koalas from the Sydney region. Prevalence of nasal colonisation varied seasonally from 12 to 38%. Cryptococcus neoformans var. gattii was cultured from 37, var. neoformans from 22 and both varieties from 5 nasal swabs. One case of cryptococcosis in a captive koala was diagnosed, and the treatment and response to therapy was described. The applicability of a streptavidin biotin-horseradish peroxidase immunohistological staining method to determine the variety and serotype of Cryptococcus neoformans in histological sections of infected koala tissues was assessed. A preliminary study was undertaken to assess the proliferative responses of koala lymphocytes to various mitogens and to chlamydial and cryptococcal antigen in infected and non-infected koalas. The proliferative response of cultured koala lymphocytes varied with the individual animal, the mitogen or antigen used and its concentration, but were invariably greater with separated peripheral blood mononuclear cells than with whole blood. Prior to investigating the immunopathogenesis of mucormycosis in the platypus, the use of various immunomarkers was validated using normal platypus lymphoid tissue. The gross structure and histology of lymphoid tissues obtained from 15 platypuses was described; including spleen, thymus, lymphoid nodules, gut-associated lymphoid tissue and bronchus-associated lymphoid tissue. With the exception of lymphoid nodules, the lymphoid tissue of the platypus was comparable in histological structure to that of therian mammals. Cross-reactive and specific antiplatypus antibodies were successfully applied to histological sections of platypus lymphoid tissue. The immunohistological appearance of the lymphoid tissues in the platypus was similar to that of eutherian and metatherian mammals, except for the detection of fewer B lymphocytes. In order to improve understanding of the pathogenesis of Mucor amphibiorum infection in the platypus, the gross, histological and immunohistological features of cutaneous lesions from 14 platypuses were described. For comparative purposes, normal platypus skin was also examined histologically and immunohistologically. Cases of mucormycosis were confirmed by cytology, histology, mycology and/or ELISA. Skin lesions varied in size, and ranged from raised red nodules or plaques, to ulcerated lesions. Lesions could be either granulomatous or pyogranulomatous, and were commonly diffuse. T cells were the predominant infiltrating lymphoid cell in the lesions and few B cells were observed in all cases. Presumptive plasma cells were observed in about half the cases.
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Kučera, Tomáš. "Formování multiagentních koalic pomocí genetických algoritmů." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2019. http://www.nusl.cz/ntk/nusl-403212.
Abstract:
This thesis discusses the basics of software agents and the way they form the multiagent coalitions. Genetic algorithms are introduced as one of the methods of solving the coalition formation problem. MAPC 2018 competition is introduced, which inspired the final design and implementation of the solution by using the tools described. A demo project was created, in which agents communicate with the MASSim server and gather data which is then used as an input into the genetic algorithm. Its purpose is to assign the agents to the tasks based on the input data, so that the tasks can be accomplished in the most effective manner possible. The results of this algorithm are evaluated in experiments which are focused on the quality of the solutions found as well as the time required for the calculation.
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Defelicibus, Alexandre. "Koala: sistema para integração de métodos de predição e análise de estruturas de proteína." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-22062016-102823/.
Abstract:
A Biologia Computacional tem desenvolvido algoritmos aplicados a problemas relevantes da Biologia. Um desses problemas é a Protein Structure Prediction (PSP). Vários métodos têm sido desenvolvidos na literatura para lidar com esse problema. Porém a reprodução de resultados e a comparação dos mesmos não têm sido uma tarefa fácil. Nesse sentido, o Critical Assessment of protein Structure Prediction (CASP), busca entre seus objetivos, realizar tais comparações. Além disso, os sistemas desenvolvidos para esse problema em geral não possuem interface amigável, não favorecendo o uso por não especialistas da computação. Buscando reduzir essas dificuldades, este trabalho propões o Koala, um sistema baseado em uma plataforma web, que integra vários métodos de predição e análises de estruturas de proteínas, possibilitando a execução de experimentos complexos com o uso de fluxos de trabalhos. Os métodos de predição disponíveis podem ser integrados para a realização de análises dos resultados, usando as métricas RMSD, GDT-TS ou TM-Score. Além disso, o método Sort by front dominance (baseado no critério de optimalidade de Pareto), proposto nesse trabalho, consegue avaliar predições sem uma estrutura de referência. Os resultados obtidos, usando proteínas alvo de artigos recentes e do CASP11, indicam que o Koala tem capacidade de realizar um conjunto relativamente grande de experimentos estruturados, beneficiando a determinação de melhores estruturas de proteínas, bem como o desenvolvimento de novas abordagens para predição e análise por meio de fluxos de trabalho.Computational Biology has developed algorithms applied to relevant problems from Biology. One of these probems is Protein Structure Prediction (PSP). Several methods have been developed on the liteture to deal with this problem. However, the reproduction of results and the comparison of the methods have not been an easy task. Accordingly, the Critical Assessment of protein Structure Prediction (CASP), has among his objectives, perform these comparisons. Besides, the developed systems for this problem have low usability, not benefiting the investigation of various methods by non experts. In order to minimize those difficulties, this project proposes Koala, a web-based system that integrates several algorithms applied to PSP and analysis, allowing the execution of complex experiments by using workflows. The prediction methods can be integrated to perform some analysis of the results, by using the RMSD, GDT-TS and TM-Score metrics. Moreover, the Sort by front dominance method (based on the criterion of Pareto optimalidad), proposed on this work, can evaluate predictions with no reference structure. The results obtained, using target proteins from recent articles and CASP11, indicate that Koala has the capability to execute a relatively large set of organized experiments, benefiting determining of better protein structures, as well as the development of new approaches for prediction and analysis through workflows.
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Mathew, Marina. "Characterisation of cytokine response to Chlamydia pecorum infection in the koala, Phascolarctos cinereus." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/78617/1/Marina_Mathew_Thesis.pdf.
Abstract:
This thesis aimed at identifying cytokine markers associated with chlamydial infection and disease in koalas which is facing many threats to its survival, Chlamydia pecorum infections being a major one. To identify immunological markers associated with chlamydial infection and disease in koalas, key cytokines such as TNF alpha, IL10, IFN gamma and IL17A were cloned and sequenced and subsequently developed Quantitative Real Time PCR (qrtPCR) assays. The thesis provides preliminary data on the role of these cytokines in koala chlamydial disease and further longitudinal studies are required to confirm the role played by cytokines in pathology and protection against C. pecorum infection in the koala.
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Kollipara, Avinash. "Investigation of genetic diversity and development of vaccine for Chlamydia pecorum infections in koala (Phascolarctos cinereus)." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/65557/1/Avinash_Kollipara_Thesis.pdf.
Abstract:
Many wild koala populations in Australia continue to experience serious declines due to factors such as disease caused by Chlamydia. This thesis is the first of its kind to investigate diversity of the chlamydial infections in wild koala populations across Australia and has made significant progress towards the development of a vaccine for koalas. The findings in this study have demonstrated that it is feasible to develop a safe and effective recombinant vaccine against Chlamydia in both disease free as well as severely diseased koalas. Most importantly, this study is also first of its kind to evaluate a multi-component vaccine that should be effective against the range of Chlamydia pecorum strains circulating in both captive as well as wild koala populations.
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Vélez, Montecinos Maximiliano Alejandro. "Koala 3D: Impresora 3D capaz de fabricar objetos de altura mayor que su propia altura." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/150603.
Abstract:
Magíster en Ciencias de la Ingeniería, Mención MecánicaActualmente las herramientas de fabricación están limitadas a producir objetos cuyas dimensiones no sobrepasen los límites de su volumen de manufactura. En el caso de las impresoras 3D la relación entre el volumen de manufactura y el tamaño de la máquina se aproxima a la unidad debido a su principio de funcionamiento. Lipson comenta en su libro Fabricated que es posible aumentar esta relación al infinito si es que la impresora 3D se acopla a un mecanismo que se mueva libremente por el espacio. En el presente trabajo se relata el proceso de desarrollo y caracterización de Koala 3D, una impresora 3D móvil que es capaz de fabricar objetos de mayor tamaño que su propia altura. Esto lo hace gracias a que continuamente modifica la posición de su volumen de manufactura al trepar la pieza (estructura) que va imprimiendo en paralelo. El desarrollo de Koala 3D se hizo dividiendo el prototipo en dos subconjuntos: una impresora 3D y un robot trepador. Para el diseño de la parte impresora se basó en modelos que funcionan mediante el método de modelado por deposición fundida e innovándose en el mecanismo que posiciona el material sobre el área de manufactura. La parte trepadora se diseñó procurando que se moviera con precisión a lo largo de la estructura impresa y que fuera capaz de soportar largas sesiones de manufactura. Para el control del prototipo se emplearon plataformas y programas dedicados al rubro de la impresión 3D que se utilizan ampliamente en comunidades hágalos-usted-mismo . El hardware Ramps 1.4 fue capaz de operar ambas partes a pesar de no estar diseñada para el control de un robot trepador o móvil. El firmware Marlin cargado en el controlador de la máquina facilitó la interacción entre el usuario y el prototipo mediante la utilización del código máquina. Luego de fabricados y calibrados los distintos mecanismos del sistema se finalizó el trabajo caracterizando y estudiando el desempeño del prototipo. La energía consumida y la calidad de los objetos manufacturados fueron similares a impresoras de escritorio utilizadas en la actualidad. También se estudiaron las oscilaciones del sistema al manufacturar una pieza estandarizada, analizando las implicancias del diseño en este fenómeno y dando recomendaciones para trabajos futuros.
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Lillo, Juan Gabriel. "Study into the intrinsic clearance of carprofen in selected species - with emphasis in the koala (Phascolarctos cinereus)." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23997.
Abstract:
Currently, a small group of drugs is being used to treat injured and sick koalas, due to the lack of pharmacokinetic data available. Drugs' clearance in koalas and other marsupials has shown to be fast and efficient, in experiments in-vivo and in-vitro. NSAIDs, Carprofen was studied in-vitro using koala liver microsomes. Experimental approach to detect and qualify it, was developed through of fluorescence detection coupled to RP- HPLC system, and it suitable to be used in substrate depletion method over different species as marsupials and mammals in a semi-high throughput approach. Carprofen phase I metabolism, shows a short half-life, a relatively rapid clearance and an enzymatic kinetic governed by Michaelis - Menten equations in koalas, as well a unique metabolite M1 detected in all samples. In-vitro Clint were: brush-tailed possums 38.47 > > koala 8.70 > ring-tail possum 8.28 (L/mL/mg protein). Apparent Michaelis-Menten constants were Kmapp = 2.002 μM and Vmaxapp = 24.95 mol/min/mg protein. Combined drug metabolism phase I and II experiments, shows a short half-life, a rapid clearance and an enzymatic kinetic governed by Michaelis - Menten equations in koalas, as well two new metabolites were detected in all samples (M2 and M3). In-vitro Clint were: koala 26.01 > brush-tailed possums > ring-tail possum 14.93 (L/mL/mg protein). Apparent Michaelis-Menten constants were Kmapp = 2.430 μM and Vmaxapp = 83.69 mol/min/mg protein. Combined drug metabolism phase I and II reactions catalysed by cytochrome P450 superfamily and UDP-glucuronosyltransferase (UGT), suggest a high apparent participation of UGT family (67%) and a significant metabolism by CYPs enzymes in phase I reactions, in koala and its critical role in xenobiotics.
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Rus, Adrian. "Movement patterns and spatio-temporal use of patches by a specialist herbivore, the koala, in a fragmented agricultural landscape." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23657.
Abstract:
Understanding how animals use their habitat is an important part of ecology because it links an individual’s life history with movement and resource exploitation. Animals have to move in some form or another to satisfy their energetic and reproductive needs, which is essential for fitness and survival. The patchy distribution of resources (i.e. food, shelter, mates) within heterogenous landscapes has a strong influence on animal movement. By analysing movement patterns of individuals, we can get a better understanding of the factors influencing the spatio-temporal use of patches. Habitat fragmentation also creates a greater isolation of resource patches, increasing the costs of movement. Therefore, understanding how the distribution and organisation of habitat patches within fragmented landscapes affects the use of patches is crucial for management and conservation of species. My overarching aim was to understand how the internal state (i.e. sex, age, health) and environmental factors influence the movement and patch use of a specialist herbivore occupying a fragmented agricultural landscape. I used free-ranging koalas (Phascolarctos cinereus) as a model to explore individual movement, temporal foraging patterns, and periodic use of patches. Together, my results provide evidence that internal and external factors driver animal movement patterns, and that habitat fragmentation is a strong drive of animal movement and space use. These insights help advance our understanding of animal movement ecology and how animals cope with the effects of habitat fragmentation, with implications for management and conservation of species occupying fragmented landscape.
46
Reinholm, Sanna. "Fenotypning med Phene Plate system av koagulas-negativa stafylokocker isolerade från centrala venkatetrar." Thesis, Örebro universitet, Hälsoakademin, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-11039.
Abstract:
Koagulas-negativa stafylokocker (KNS) klassas som en viktig del av hudens normalflora. Vid skador på hudens barriär som en inläggning av centrala venkatetrar (CVK) innebär kan dock KNS få tillträde till normalt sterila lokaler där de kan orsaka infektion. Vid utodling av borttagna CVK från patienter resistensbestäms bara några enstaka kolonier vilket gör det lätt att missa förekomst av flera olika stafylokock-kloner. Syftet med studien var att undersöka hur ofta en eller flera olika KNS-kloner förekommer på CVK från patienter, samt om det förekommer gemensamma kloner av KNS på CVK från olika patienter. Kolonier från CVK prov analyserades med den biokemiska fingerprintingmetoden Phene Plate-system (PhP). Resultatet visade 37 stycken CVK prov innehållande en klon, 23 stycken prov där det fanns 2 separata kloner, samt 6 prov med 3 kloner. Jämförelsen av kolonier ur prov från olika patienter resulterade i kluster med många gemensamma PhP-typer. I de 3 största klustren fanns 31, 15, respektive 8 kolonier representerande olika patienter. Den betydande andelen polyklonala CVK prov leder till risken att missa en mer resistent klon vilket då kan få konsekvensen felaktig antibiotikabehandling av patient. Att många patientprov hade en gemensam KNS-klon tyder på spridning av speciellt virulenta stammar inom sjukhus.
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Ryan, Jennifer Elizabeth. "A Bee-Hive, A Koala Den, A Yoga Studio, and A Clinic: Acknowledging the Uniqueness of Our Writing Center Spaces." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1619624903412554.
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Alfano, Niccolò [Verfasser]. "High throughput approaches to studying virology: applications to the koala retrovirus KoRV and gibbon ape leukemia virus GALV / Niccolò Alfano." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1115722492/34.
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Howard, Eliza May. "Prevalence and molecular characterisation of Trypanosoma spp. in two wild koala populations; Moreton Bay, Queensland and Mount Lofty, South Australia." Thesis, Howard, Eliza May (2022) Prevalence and molecular characterisation of Trypanosoma spp. in two wild koala populations; Moreton Bay, Queensland and Mount Lofty, South Australia. Honours thesis, Murdoch University, 2022. https://researchrepository.murdoch.edu.au/id/eprint/65905/.
Abstract:
The koala (Phascolarctos cinereus) is an iconic Australian marsupial that is under threat of extinction across two thirds of its range, with populations recently listed as ‘endangered’ in Queensland (QLD), New South Wales (NSW) and the Australian Capital Territory (ACT). Many risk factors have been implicated in the koala population decline, including habitat loss, vehicle collisions, dog attack and infectious diseases such as chlamydiosis and koala immune deficiency syndrome caused by koala retrovirus (KoRV).
Trypanosomes are blood-borne protozoan parasites that can infect all classes of mammals and are known to cause serious disease in humans and domestic livestock worldwide. Recent studies have identified numerous Trypanosoma species in a range of Australian marsupials, including the koala which is known to harbour up to six species in either single or mixed infections: Trypanosoma irwini, Trypanosoma gilletti, Trypanosoma copemani, Trypanosoma vegrandis, Trypanosoma noyesi and Trypanosoma sp. AB-2017. Importantly, preliminary data from analyses of hospitalised koalas in QLD suggest that trypanosome infections (alone or with concurrent diseases) may adversely affect koala health and survival.
Whilst a large number of studies have been conducted on chlamydia and KoRV, there is still a paucity of research investigating the prevalence, diversity and clinical impact of trypanosomes in koalas. In particular, there is a dearth of research comprising random, representative samples from various wild koala populations across Australia, including more stable populations from South Australia (SA).
This descriptive cross-sectional study utilised nested PCR, targeting partial fragments of the nuclear 18S ribosomal RNA (18S rRNA) gene, to screen blood samples from wild-caught koalas for the presence of trypanosomes. Samples were randomly collected from koalas belonging to two distinct wild populations; Moreton Bay, Queensland (QLD) (n= 72) and Mount Lofty, South Australia (SA) (n= 89). The overall prevalence of Trypanosoma in both populations was 47.2% (76/161; 95% CI: 39.3-55.2%). The prevalence of trypanosomes in koalas from Moreton Bay was 80.6% (58/72; 95% CI: 69.5-88.9%), whereas the prevalence in koalas from Mount Lofty was significantly lower: 20.2% (18/89; 95% CI: 12.4-30.1%). Sanger sequencing of PCR positive products was performed and phylogenetic analysis conducted on the partial 18S rDNA fragments obtained. A total of 35 Trypanosoma isolates from Moreton Bay koalas were identified as Trypanosoma irwini (n= 36), with intra-specific genetic variations ranging from 0% - 2.99%. Remaining QLD isolates (n=16) were identified as Trypanosoma gilletti, with genetic distances ranging from 0% - 1.20%. These results are similar to findings from previous studies of hospitalised koalas from QLD and NSW.
All Trypanosoma isolates from the Mount Lofty population (n = 18) formed a unique, highly diverse clade within the Trypanosoma cruzi clade of trypanosomes. These novel sequences displayed a high genetic variation amongst each other (genetic distances = 0% - 7.04%) and from their most closely related species (T. sp 1EA-2008) (genetic distances = 1.90% - 7.73%). To the best of the author’s knowledge, this is the first report of trypanosomes in koalas from SA. The unique phylogenetic position of the isolates identified, associated with a relatively high genetic distance from their most closely related known Trypanosoma sp., suggests that they may potentially represent novel Trypanosoma spp.. Further analyses of full-length 18S sequences and additional loci are required to confirm this finding and reliably delimit the species.
Sanger sequencing of seven PCR positive isolates from Moreton Bay koalas revealed mixed chromatograms and were excluded from phylogenetic analyses. Further analyses using next-generation metabarcoding are required to identify and characterise mixed trypanosome infections in all positive samples detected in the present study, particularly those that produced mixed Sanger sequencing chromatograms.
This study provides valuable novel baseline data which will contribute to the growing knowledge base of Australian trypanosomes, and future studies on the potential impact of Trypanosoma spp. (with and without concurrent infectious diseases) on the health and conservation of koalas.
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Hemsley, S. "Investigations of mucosal immunology and diseases of mucosal surfaces in marsupials." Thesis, The University of Sydney, 1996. http://hdl.handle.net/2123/19216.