Dissertations / Theses on the topic 'Frogs'
To see the other types of publications on this topic, follow the link: Frogs.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Frogs.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Tyler, Michael J. "The biology and systematics of frogs : contributions submitted to The University of Adelaide /." Title page and summary only, 2002. http://web4.library.adelaide.edu.au/theses/09SD/09sdt983.pdf.
Abstract:
Thesis (D.Sc.)--University of Adelaide, Dept. of Environmental Biology, 2002.Vol. [2] comprises 6 reprints of published monographs in box folder; but numbered within the publications submitted listing (90 items), and within the 3 categories identified; at the beginning of vol. 1. Includes bibliographical references.
2
McDaniel, Tana. "Direct and indirect interactions between two ranid frogs, pickerel frogs (Rana palustris) and leopard frogs (Rana pipiens )." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0016/MQ55693.pdf.
3
Dickson, Nancy J. "The natural history and possible extirpation of Blanchard's Cricket Frog, Acris crepitans. blanchardi, in West Virginia." Huntington, WV : [Marshall University Libraries], 2002. http://www.marshall.edu/etd/descript.asp?ref=95.
Abstract:
Thesis (M.S.)--Marshall University, 2002.Title from document title page. Document formatted into pages; contains ix, 115 p. with maps and illustrations. Includes vita. Includes bibliographical references (p. 34-40).
4
Bayne, Kimberly Ann. "The natural history and morphology of the eastern cricket frog, Acris crepitans crepitans, in West Virginia." Huntington, WV : [Marshall University Libraries], 2004. http://www.marshall.edu/etd/descript.asp?ref=387.
Abstract:
Thesis (M.S.)--Marshall University, 2004.Title from document title page. Document formatted into pages; contains vi, 103 p. including illustrations and maps. Includes bibliographical references (p. 100-103).
5
Doak, Naomi C. "Phylogeography, Dispersal and Movement of Fleay's Barred Frog, Mixophyes fleayi." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/365483.
Abstract:
This thesis investigates historical and current dispersal in Mixophyes fleayi, an endangered, wet forest-restricted frog species, found exclusively on the Great Dividing Range of mid-eastern Australia. The phylogeographic structuring and genetic divergence among isolated forest fragments and the presence of multiple populations within continuous forest is used to investigate historical connectivity of populations and current dispersal. Indirect genetic methods as well as field based direct methods are also used to investigate dispersal and movement. These results are used to explore the consequences of dispersal in terms of conservation and management of the species. Few studies have investigated genetic differentiation between upland mesic rainforest areas in southern parts of Queensland, which potentially acted as historical refugia for rainforest dependant species. The broad scale investigation of genetic diversity and structure in M. fleayi, using sequence variation within the mitochondrial ND2 gene, revealed two scales of genetic structure. Two deeply divergent and geographically isolated lineages were found to group populations across the Brisbane River Valley, with isolation of the Conondale Range in the north from all other populations to the south. This can be attributed to regional isolation of rainforest fragments during the Pliocene. Lower levels of genetic variation and sequence divergence were found across forest fragments within the southern distribution of the species (Springbrook, Mount Barney, McPherson, Main, Upper Richmond and Nightcap Ranges), resulting from more recent fragmentation and restricted dispersal related to expansion and contraction of rainforest habitat during the Pleistocene.
Genetic structure among populations indicates that comparatively high levels of genetic differentiation exist on very small geographic scales relative to other amphibian species. These data suggest isolation by distance within forest fragments and significant genetic structuring between populations separated by more than two kilometres. Despite the relatively low vagility of individuals, terrestrial dispersal occurs among nearby streams, both within as well as across major catchments. The extent of shared subcatchment boundary between nearby streams provided some indication of the probability and magnitude of gene flow, with sites that share more subcatchment boundaries showing lower levels of genetic differentiation. The indirect genetic evidence of restricted dispersal within the species is supported by mark-recapture, spooling and radio-tracking investigations of movements made by individual M. fleayi in the field. The activity of both sexes is characterized by intervals of small, localized movements. In adult females this behaviour is punctuated by large movements that generally displace individuals away from breeding habitat after relatively short amounts of time spent at the stream. While migration of females between breeding sites was not detected, the movements made by adult females are large enough to enable dispersal between breeding sites, although such dispersal events are probably infrequent. Adult males are extremely philopatric and remain within the breeding area, rarely moving away from the stream, making exchange of adult males between populations extremely unlikely. The management of M. fleayi is particularly important given the potential impact recent declines in both population size and number may have had on genetic variation. Intraspecific genetic divergence, across the Brisbane River Valley, highlights the need to conserve populations in isolated forest fragments both north and south of this putative barrier. Within fragments of continuous forest habitat, evidence of restricted, infrequent terrestrial dispersal of individuals suggests colonization of vacant habitat is unlikely, particularly among streams that do not share subcatchment boundaries. To maintain important, albeit low levels of gene flow and movement between nearby streams, it is critical that habitat connectivity between populations is maintainedThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental and Applied Science
Full Text
6
Cunningham, Michael. "Vicariance, speciation and diversity in Australopapuan rainforest frogs /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16280.pdf.
7
Schäuble, Chloe Sarah. "Geographic variation in the widespread Australian frogs Limnodynastes tasmaniensis and L. peronii /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16936.pdf.
8
Cramp, Rebecca L. "The effects of aestivation and re-feeding on the structure and function of the gut in the green-striped burrowing frog, Cyclorana alboguttata /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18663.pdf.
9
Marshall, Vincent Timothy. "Social aspects of communication in gray treefrogs : intraspecific and interspecific interactions /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3115569.
10
Aihara, Ikkyu. "Synchronization of Calling Frogs." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142353.
11
Havens, Sarah Beth. "The role of skeletal development in body size evolution of two North American frogs." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2010. http://scholarsmine.mst.edu/thesis/pdf/Havens_2010_09007dcc807be556.pdf.
Abstract:
Thesis (M.S.)--Missouri University of Science and Technology, 2010.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed June 7, 2010) Includes bibliographical references.
12
Doak, Naomi C. "Phylogeography, dispersal and movement of Fleay's Barred Frog, Mixophyes fleayi." Click here to access, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060221.144328.
13
Rondeau, Sylvie L. "Variables determining buoyancy in juvenile mink frogs, Rana septentrionalis, with comparisons to boreal chorus frogs, Pseudacris triseriata maculata, and wood frogs, Rana sylvatica." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0028/MQ51793.pdf.
14
Sias, Jaime. "Natural history and distribution of the Upland Chorus Frog, Pseudacris feriarum Baird, in West Virginia." Huntington, WV : [Marshall University Libraries], 2006. http://www.marshall.edu/etd/descript.asp?ref=629.
Abstract:
Theses (M.S.)--Marshall University, 2006.Title from document title page. Includes abstract. Document formatted into pages: contains xiii, 82 p. including col. illustrations and maps. Bibliography: p. 66-76.
15
Norris, Rachel Mary. "Morphology and systematics of the Solomon Island Ranid frogs." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phn858.pdf.
Abstract:
"December 2002" Bibliography: leaves 230-241. Ch. 1. Introduction -- Ch. 2. Historical account -- Ch. 3. Morphometrics -- Ch. 4. Osteology of Solomon Islands ranids -- Ch. 4. Karyology of the Solomon Islands ranids -- Ch. 6. Phylogenetic analysis -- App. 1: Material examined -- App. 2: Discriminant function analysis -- App. 3: Character descriptions. "This study validates the Solomon Islands taxa (using morphometrics) and explores the biology of the Solomon Islands ranids, with detailed osteological descriptions, external morphology and karyology. Using characters from these data sets a cladistic analysis using parsimony reconstructed a phylogeny of thes frogs...Phylogenetic analysis using maximum parsimony found three equally parsimonious trees. Subsequent character reanalysis (successive weighting) produced one parsimonious tree. The phylogenies indicate multiple invasion events into the Solomon Islands by these ranid frogs and despite the high level of endemism, monophyly is not supported."
16
Hamilton, Amy M. "A taxonomic study of the genus Acris and the status of Acris crepitans blanchardi (Harper), Blanchard's cricket frog, in southern Ohio and western West Virginia." [Huntington, WV : Marshall University Libraries], 2008. http://www.marshall.edu/etd/descript.asp?ref=888.
17
Nájera-Hillman, Eduardo. "Leiopelma hochstetteri Fitzinger 1861 (Anura: Leiopelmatidae) habitat ecology in the Waitakere Ranges, New Zealand a thesis submitted to AUT University in partial fulfilment of the degree of Doctor of Philosophy, 2008 /." Click here to access this resource online, 2009. http://hdl.handle.net/10292/736.
18
Xin, Ling. "Stability of the frog motor nerve terminal roles of perisynaptic Schwann cells and muscle fibers /." Connect to this title online, 2008. http://scholarworks.umass.edu/theses/101/.
19
Vradenburg, John. "Distribution and abundance of anurans in southeast Missouri." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4258.
Abstract:
Thesis (M.S.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (January 10, 2007) Includes bibliographical references.
20
Lowe, Katrin. "Landscape Ecology and Bioclimatic Conditions of the Wallum Sedge Frog (Litoria olongburensis) in Coastal Wallum Wetlands of Eastern Australia: Resilience to Climate Change." Thesis, Griffith University, 2013. http://hdl.handle.net/10072/366084.
Abstract:
Many species are threatened by rapidly changing climate and amphibians may be particularly vulnerable. As ectotherms, all aspects of amphibian physiology and life history are directly or indirectly influenced by temperature and moisture. For amphibian conservation, a clear priority is to investigate impacts of climate change on key environmental parameters within breeding habitats, as well as the ecology of threatened species. This information is vital for assessing species vulnerability to climate change and informing conservation efforts. Wallum frogs are species that are restricted to naturally acidic, oligotrophic coastal wetlands of eastern Australia. There is a paucity of ecological data on wallum frogs and their breeding habitats however climate change predictions suggest they are likely to be exposed to changes in the timing and intensity of precipitation, and increases in temperature. Consequently, the aim of this study was to enhance our understanding of the bioclimatic conditions of threatened wallum frogs at a landscape scale. This information was then used to assess climate change vulnerability for these wallum associated frog species, particularly the threatened wallum sedge frog (Litoria olongburensis). This study determined environmental factors influencing reproductive behaviours of L. olongburensis, namely calling phenology and breeding effort. Also, the impacts of fire on wallum frog ecology and morphology were assessed, as their habitat is exposed to regular and intense fires, which are predicted to increase in frequency and/or severity in the future.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
21
Humfeld, Sarah Conditt. "Signaling, intersexual dynamics and the adoption of alternative male mating behaviors in green treefrogs, Hyla cinerea /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3115556.
22
Pearl, Christopher A. "Demonstration of pheromonal activity in the breeding glands of dwarf African clawed frogs (Hymenochirus sp.)." Scholarly Commons, 2000. https://scholarlycommons.pacific.edu/uop_etds/529.
Abstract:
Anurans rely mainly on vocalizations for mate attraction while urodeles rely mainly on pheromones. However, the presence of breeding glands suggests that anurans may also communicate with pheromones during reproduction. Previous studies have shown that male Hymenochirus sp. are able to attract females in a Y-maze, most likely through chemical means, but the source of the attractant has not been identified. By exposing female Hymenochirus sp. to choice tests in a Y -maze it was demonstrated that the breeding glands of male Hymenochirus sp. are the source of a mate-attractant pheromone. This study represents the first experimental evidence for a pheromonal function of breeding glands and further supports the idea that anurans utilize pheromones in reproduction. Evidence is also presented suggesting that the mate attraction is temperature sensitive with an upper limit around 30°C.
23
Churchill, Thomas Allen Carleton University Dissertation Biology. "Metabolic biochemistry of freeze tolerance in vertebrates." Ottawa, 1992.
24
Schadich, Ermin. "Skin peptide defences of African clawed frogs (Xenopus laevis) and New Zealand Litoria frogs against bacterial dermatosepticemia." Thesis, University of Canterbury. School of Biological Sciences, 2008. http://hdl.handle.net/10092/4437.
Abstract:
In frogs, part of the important immune defence system of their skin is the secretion of antimicrobial peptides from granular glands. This study investigated the immune function of skin peptides in protection against bacterial pathogens associated with infectious bacterial dermatosepticemia under a number of environmental conditions and at certain stages of the life cycle of frogs. The natural peptide mixture of skin peptides was collected from skin secretions of three semi-aquatic Litoria frog species L. aurea, L. raniformis and L. ewingii and aquatic Xenopus laevis and assayed for activity against the bacterial pathogens: Aeromonas hydrophila, Chryseobacterium meningosepticum, Citrobacter freundii, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Serratia liquefaciens. The peptide mixtures of three frog species Xenopus laevis, Litoria aurea and Litoria raniformis showed activity against C. freundii, C. meningosepticum, K. pneumoniae and P. aeruginosa in vitro indicating a likely protective function. One Litoria species, L. ewingii, had a peptide mixture that did not have activity against any pathogen. Subsequently, in experimental exposure of animals to the pathogen K. pneumoniae, this species was found to be susceptible to disease while the other sympatric species L. raniformis was found to be resistant. A strong correlation was shown between composition of skin peptides and resistance to disease. A comparison of the production and activity of skin peptides from four frog species showed the aquatic X. laevis to have more effective immune defence against bacterial pathogens than three tested Litoria species. X. laevis produced significantly greater amount of bioactive peptide mixture than three tested Litoria species. Three pathogens A. hydrophila, P. mirabilis and S. liquefaciens are abundant components of the skin microbiota of healthy frogs and were found to be resistant to the peptide mixtures of all four frog species tested. It was shown that one pathogen, A. hydrophila, had the ability to secrete proteases which could inactivate skin peptides. Thus while skin peptides could function against several pathogens, some pathogens might have co-evolved to resist skin peptides. A comparison of the peptide mixtures from skin secretions of adults, metamorphs and larvae of L. ewingii using liquid chromatography-mass spectrometry analyses showed that peptide mixtures of post metamorphic animals, adults and metamorphs, had a species-specific profile that included the antimicrobial peptide uperin 7.1, while the larval peptide mixture did not contain uperin 7.1 or any other known species-specific peptide. This finding indicates the absence of a secretory mechanism that could compensate for the absence of granular glands in larvae. Analyses of the production and activity of skin peptides of L. raniformis after exposure to two different environmental stressors, low environmental temperature and pesticide carbaryl, showed that the total amount of bioactive peptide was significantly reduced which could consequently increase susceptibility to disease. Thus suppression of skin peptides could be a possible mechanism for synergism between the important stressors and pathogens in disease development.
25
Parris, Matthew James. "Analysis of fitness determinants in an anuran hybrid zone (Rana blairi and Rana sphenocephala) : the evolutionary potential of natural hybridization /." free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9953888.
26
Yeh, Jennifer Jean. "Ontogeny and evolutionary morphology of the skeleton in frogs." Access restricted to users with UT Austin EID, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3037029.
27
Kaveh, Farzaneh [Verfasser]. "Wet bioadhesion in tree frogs / Farzaneh Kaveh." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1058655930/34.
28
Edwards, Danielle L. "Biogeography and speciation of southwestern Australian frogs." University of Western Australia. School of Animal Biology, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0058.
Abstract:
[Truncated abstract] Southwestern Australia is a global biodiversity hotspot. The region contains a high number of endemic species, ranging from Gondwanan relicts to more recently evolved plant and animal species. Biogeographic models developed primarily for plants suggest a prominent role of Quaternary climatic fluctuations in the rampant speciation of endemic plants. Those models were not based on explicit spatial analysis of genetic structure, did not estimate divergence dates and may be a poor predictor of patterns in endemic vertebrates. Myobatrachid frogs have featured heavily in the limited investigations of the biogeography of the regions fauna. Myobatrachid frogs are diverse in southwestern Australia, and while we know they have speciated in situ, we know little about the temporal and spatial patterning of speciation events. In order to gain insight into the biogeographic history and potential speciation patterns of Myobatrachid frogs in the southwest I conducted a comparative phylogeography of four frog species spanning three life history strategies. I aimed to: 1) assess the biogeographic history of individual species, 2) determine where patterns of regional diversity exist using a comparative framework, 3) determine whether congruent patterns across species enable the development of explicit biogeographic hypotheses for frogs, and 4) compare patterns of diversity in plants with the models I developed for frogs. I conducted fine-scale intraspecific phylogeographies on four species. ... Geocrinia leai: deep divergences, coincident with late Miocene arid onset, divide this species into western and southeast coastal lineages, with a third only found within the Shannon-Gardner River catchments. Phylogeographic history within each lineage has been shaped by climatic fluctuations from the Pliocene through to the present. Arenophryne shows the first evidence of geological activity in speciation of a Shark Bay endemic. Divergence patterns between the High Rainfall and Southeast Coastal Provinces within C. georgiana are consistent with patterns between Litoria moorei and L. cyclorhynchus and plant biogeographic regions. Subdivision between drainage systems along the southern coast (in M. nichollsi, G. leai and the G. rosea species complex) reflect the relative importance of distinct catchments as refuges during arid maxima, similarly the northern Darling Escarpment is identified as a potential refugium (C. georgiana and G. leai). Divergences in Myobatrachid frogs are far older than those inferred for plants with the late Miocene apparently an important time for speciation of southwestern frogs. Speciation of Myobatrachids broadly relates to the onset of aridity in Australia in the late Miocene, with the exception of earlier/contemporaneous geological activity in Arenophryne. The origins of subsequent intraspecific phylogeographic structure are coincident with subsequent climatic fluctuations and correlated landscape evolution. Divergence within frogs in the forest system may be far older than the Pleistocene models developed for plants because of the heavy reliance on wet systems by relictual frog species persisting in the southwestern corner of Australia.
29
Kaiser, Hinrich. "Systematics and biogeography of eastern Caribbean frogs." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41632.
Abstract:
This study examines the systematics and biogeography of frogs in the Eastern Caribbean, a biogeographical province consisting of the Lesser Antilles, Trinidad, and Tobago. A comprehensive collection of specimens was subjected to an analysis incorporating morphometric, osteological, and biochemical approaches. An investigation of $ alpha$-level taxonomy revealed the presence of four additional taxa: Colostethus chalcopis sp. nov. on Martinique, Eleutherodactylus amplinympha sp. nov. on Dominica, E. euphronides comb. nov. on Grenada, and E. shrevei comb. nov. on St. Vincent. Based on species distributions and detailed analyses of the largely congruent data sets, Eastern Caribbean frogs can be grouped into two major categories, those originating with South American stock and those of Greater Antillean ancestry. A South American origin is obvious for species which have no congeneric relatives in the Greater Antilles, e.g. C. chalcopis, Leptodactylus fallax, L. wagneri. Among the Eleutherodactylus species, northern Eastern Caribbean taxa form a monophyletic group within the E. auriculatus species group; the topology of relationships is ((E. barlagnei, E. pinchoni) ((E. amplinympha, E. martinicensis) E. johnstonei)). The southern Eastern Caribbean species may or may not form a monophyletic group, but E. euphronides and E. shrevei are sister taxa. The topology for these species is (E. urichi (E. terraebolivaris (E. euphronides, E. shrevei))). Thus, the Eastern Caribbean forms a biogeographic link between the large South American and Greater Antillean radiations of Eleutherodactylus; Eleutherodactylus is the only truly circum-Caribbean frog genus. Furthermore, historical evidence shows that the patchy, Caribbean-wide distribution of E. johnstonei is the direct result of accidental introduction mitigated by humans during the past three centuries.
30
Wycherley, Julia T. M. "Bioacoustics and ecology of European water frogs." Thesis, University of Sussex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398351.
31
Zeisset, Inga. "Molecular ecology of North European water frogs." Thesis, University of Sussex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326908.
32
Gose, Christopher Todd. "Dead frogs, birds and a light bulb." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1321900608.
33
Kulkarni, Saurabh S. "Endocrine Mechanisms Underlying Phenotypic Evolution in Frogs." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342106009.
34
Lyu, Peng. "Functional genomic studies of selected Eurasian frogs." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695660.
Abstract:
Amphibians have existed on Earth for more than 300 million years. Most amphibians can survive in a wild range of living environments. Some of their living environments are fulfilled with pathogen microorganisms. The skin of amphibians produces a complex noxious/toxic chemical cocktail from specialised granular glands to against these microorganisms. This thesis describes several novel bioactive peptides which were identified from the skin secretions of the Chinese Bamboo odorous frog, Odorrana versabilis, the Chinese Black-spotted Pond frog, Pelophylax nigromaculatus and the Eurasian edible frog, Pelophylax kl. esculentus, by using reverse phase HPLC and molecular cloning. The first discovery in this study was ornithokinin, obtained from the skin secretion of Odorrana versabilis. In addition, a novel Bowman-Birk like trypsin proteinase inhibitor peptide with strong myotropic activity, named QUB 1813, was isolated from the skin secretion of the Eurasian edible frog, Pelophylax,kl. esculentus. A novel antimicrobial peptide, esculentin-2Blm, was then isolated from the skin secretion of Pelophylax kl. esculentus. These novel antimicrobial peptides show dramatic antimicrobial activities but with associated relatively high haemolytic activities. Finally, a novel myotropic peptide, named QUB 1067, was obtained from the skin of the Chinese Black-spotted Pond frog, Pelophylax nigromaculatus. QUB 1067 has a completely novel primary structure and exhibits contractile activity on isolated rat uterus smooth muscle tissues. All of these bioactive peptides were synthesised by employing PS3 solid-phase Fmoc chemistry. The synthetic replicates were used in the bioactive assays, such as antimicrobial activity assays, haemolytic assays, smooth muscle assays and trypsin inhibitory assays.
35
Eto, Koshiro. "Systematic studies of two Japanese brown frogs." Kyoto University, 2014. http://hdl.handle.net/2433/188796.
Abstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第18358号
人博第671号
新制||人||161(附属図書館)
25||人博||671(吉田南総合図書館)
31216
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 松井 正文, 教授 加藤 眞, 教授 市岡 孝朗
学位規則第4条第1項該当
36
Samuel, Diana S. "The bioadhesion of tree- and torrent frogs." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5196/.
Abstract:
Tree frogs adhere to surfaces using their toe pads. These pads secrete a fluid which enables them to adhere using a temporary adhesive mechanism known as wet adhesion. In keeping with the principles that govern this type of mechanism, the toe pads should be capable of adhering sufficiently and detaching effortlessly. However, the vast majority of research in this area has centred on static experiments, thus giving no real indication of the dynamic activity of the animal. Therefore, one aspect of this PhD project was to investigate the biomechanics of tree frog locomotion, focussing particularly on the kinematics and forces involved during toe pad detachment. Tree frog toe pads do indeed possess a rapid, efficient detachment mechanism, the toe pads simply peeling off of the surface from the rear, requiring very little force. The impact of this at higher scales was reflected in the force profiles of individual limbs, and in the global kinematics of the frog during locomotion. In addition to this, the wet adhesive mechanism itself was investigated by assessing the performance of tree frogs in a range of challenging conditions, including on overhangs and flooded surfaces. The latter condition compromises a key component of the wet adhesive mechanism; however, torrent frogs perpetually clamber across wet rocks in the vicinity of waterfalls, and yet are able to maintain their attachment. Therefore, the second aspect of this project was to compare the adhesive capabilities of tree- and torrent frogs, and propose explanations for the differences in their performance. Whilst comparable on dry, smooth surfaces, the adhesion of torrent frogs on rough, flooded substrates was far superior to that of tree frogs. Several explanations for this are offered, including the utilisation of a greater proportion of their ventral contact area, and a toe pad morphology that is optimised for such conditions. The results of this PhD project may provide a functional and morphological ‘blueprint’ for the development of toe pad mimics that can adhere in wet conditions.
37
Hartigan, Ashlie. "Myxosporean Parasites in Australian Frogs and Tadpoles." Thesis, The University of Sydney, 2012. http://hdl.handle.net/2123/8900.
Abstract:
The investigation of new threats to amphibian conservation is a priority of researchers and wildlife managers. Emerging infectious diseases are one of the most threatening processes to wildlife around the world including amphibians. Australian frogs have suffered large scale declines and extinctions from pathogens such as chytrid fungus (Batrochochytrium dendrobatidis). The once overly abundant Green and golden bell frog (Litoria aurea) has declined over 90% of its range with disease listed as a key threat. A routine pathogen screen of tadpoles from a captive breeding population of Green and golden bell frogs found an unknown parasitic infection in the brains, bile ducts and gallbladders of tadpoles (later confirmed as Myxosporea). It was this preliminary identification that was the impetus for my thesis. Myxosporean parasites found in Australian frog gallbladders were thought to be Cystodiscus immersus from Central and South America. The parasite was assumed to have been introduced to Australia with the Cane toad (Rhinella marina, syn. Bufo marinus) in 1935. Cystodiscus immersus was supposed to have translocated with the Cane toad from native Brazil and was infecting a broad range of Australian frog species with no apparent host impact. The aim of this thesis was to challenge all aspects of this assumption, to establish the true myxosporean species present in Australian frogs, if it was an exotic infection, if it was an emerging pathogen and what threat did it pose to hosts. The parasite found in Australian frogs and tadpoles was examined using histological and ultrastructural morphology as well as molecular identification. This revealed there was in fact two myxosporean species in multiple species of frogs and tadpoles. Sequencing of partial small iv subunit and large subunit as well as the internal transcribed spacers (ITS1 and ITS2) of ribosomal DNA regions confirmed these were distinct species (differing 9%, 7%, 34% and 37% at each region respectively). They were in fact separate species infecting multiple Australian host species,samples of C. immersus from Brazil were compared to establish if either of these was the exotic C. immersus. We found instead that these were completely unrelated despite sharing similar spore morphology. In addition the Brazil material revealed the cryptic diversity of myxosporea in frog gallbladders around the world and the ambiguous identity of Cystodiscus immersus. To determine if the parasites were emerging, the presence of these parasites in 130 years was established using voucher specimens. Four native species and the exotic Cane toad were examined for gallbladder myxospores from 1879 to 2009, the first positive was in 1966 in Green tree frog outside of Sydney. The prevalence of myxosporea increased in both native and exotic species over the last 40 years including the threatened Green and golden bell frog. The emergence of these parasites is a cause for concern, especially when found in endangered species. Close scrutiny of these parasites prompted the formal description of Cystodiscus axonis and Cystodiscus australis, resurrecting the original genus name proposed by Lutz in 1889. The description revealed diagnostic features previously unknown for frog gallbladder myxosporea species. Scanning electron microscopy revealed filiform polar appendages on the myxospores of C. axonis, absent in C. australis. In addition, histological examination showed unique developmental stages in the nervous tissue of tadpoles and frog hosts infected with C. axonis, these stages are only found in hosts infected with this parasite. The use of development stages as a species diagnostic character has not been previously reported for any amphibian myxosporea as yet. The genetic and morphological differences between C. axonis and C. australis prompted the development of a species specific multiplex PCR using ITS1, 5.8S and ITS2 ribosomal DNA. Multifaceted diagnostic tools (morphology and species specific PCR) demonstrated significant disease associated with these pathogens in native and exotic frog species. Seven host species were morphologically examined for Cystodiscus infection showing endangered species to have significant disease associated with infection. Cystodiscus axonis was linked to neurological signs,haemorrhage, necrosis and gliosis in Southern bell frogs (Litoria raniformis), Green and golden bell frogs (Litoria aurea), Booroolong frogs (Litoria booroolongensis), and the recently rediscovered Yellow spotted bell frogs (Litoria castanea). Cystodiscus spp. infection in the bile ducts of tadpoles was associated with biliary hyperplasia, loss of hepatocytes and inflammation. These lesions were statistically associated with the presence of infection in the Green and golden bell frog. This research disproved an assumption about myxosporean parasites that had held for 25 years. The disease found with Cystodiscus parasite infection in Australian frogs and tadpoles, as well as the previously unknown biodiversity in this cryptic species complex, highlight a number of areas in need of further research. This work has provided insight into the importance of multifaceted approaches to species identification and amphibian pathogen surveillance which uncovered a threat to endangered Australian amphibians, now listed as one of the key disease threats to frogs by the Department of Environment and Health (Australia) in 2011.
38
Madison, Amanda L. "Effects of male breeding gland in hymenochirus on female reproductive output." Scholarly Commons, 2005. https://scholarlycommons.pacific.edu/uop_etds/610.
Abstract:
Normal male dwarf African clawed frogs, Hymenochirus sp., possess bilateral, sexually dimorphic, subcutaneous breeding glands just posterior to the forelimbs. Previous studies have shown these glands release pheromones that attract conspecific females. This thesis shows the pheromones also stimulate the reproductive system of conspecific females. Females exposed to normal males prior to mating then allowed to mate with the normal males released a higher number of eggs than females who were not exposed to normal males prior to mating. Microscopic examination of ovarian tissue revealed that females exposed to normal males also produced more highly-developed oocytes than did females not exposed to normal males. These results suggest male Hymenochirus use pheromones not only to attract potential mates, but to increase female receptivity and readiness to mate. Evolutionarily, these pheromonal effects would likely benefit males by increasing their chances of breeding, increasing the number of eggs released by their mates, and thus the number of offspring in the next generation.
39
Kindermann, Christina. "Behavioural Ecology, Reproductive Biology and Colour Change Physiology in the Stony Creek Frog (Litoria wilcoxii)." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/367513.
Abstract:
Many animals possess the remarkable ability to change their skin colour. Colour change can have several potential functions, including communication, thermoregulation and camouflage. However, while the physiological mechanisms and functional significance of colour change in other vertebrates have been well studied, the role of colour change in amphibians is still relatively unknown and a disconnection between morphology, physiology and function exists in the literature (review presented in chapter 2).
In this thesis, I investigate these multidisciplinary components to understand the processes and functions of colour change in stony creek frogs (Litoria wilcoxii), which are known to turn bright yellow during the breeding season. By (1 – Chapter 3) examining the distribution and structure of dermal pigment cells, (2– Chapter 4) determining hormonal triggers of rapid colour change, (3– Chapter 5) investigating seasonal colour, hormone and disease relationships and (4– Chapter 6) determining the evolutionary functions of colour change, I provide a comprehensive explanation of this phenomenon in L. wilcoxii.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
40
Guderyahn, Laura B. "Nationwide assessment of morphological abnormalities observed in amphibians collected from United States national wildlife refuges." Virtual Press, 2006. http://liblink.bsu.edu/uhtbin/catkey/1339147.
Abstract:
Previously, amphibian malformations had only been studied at the site, state and regional levels, limiting our understanding of the types of malformations most commonly occurring in wild populations across the country. This study presents the results of radiographic analyses performed on morphologically abnormal amphibians collected from National Wildlife Refuges in 27 states and 6 of 7 US Fish and Wildlife Service regions. Despite considerable differences in species composition and ecological factors (e.g., habitat type, climate and land use), it was observed that abnormalities were remarkably similar across regions of the country. One regional difference that was noted was that higher proportions of forelimb and craniofacial abnormalities were observed in the western regions (regions 1 and 7) compared to the eastern ones. However, the uneven distribution of these abnormalities across sites, suggest that these elevated proportions may not be characteristic of region 1. Differences in species composition as well as in ecological factors such as habitat type and climate are potential explanations for this pattern in region 7. Given the known differences in regional causes, the results of this study suggest that these stressors may be affecting amphibian development in the same manner to produce primarily hindlimb reductions. Continued research comparing the types of abnormalities produced in different areas of the country as well as what stressors are present is essential to identify cause and affect relationships at sites hosting abnormal amphibians.Department of Biology
41
Christy, Michelle T. "The ecology and conservation biology of the green and golden bell frog, Litoria aurea, (Lesson 1829), (Anura: Hylidae)." Phd thesis, School of Biological Sciences, 2001. http://hdl.handle.net/2123/8979.
42
Tucker, Abigail Saffron. "Tail development in Xenopus laevis." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297296.
43
Will, Lindsey Noel. "Genetic variability between populations of the critically endangered frog Microbatrachella capensis, Boulenger 1910 (Anura: Ranidae: Cacosterninae)." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-07302008-145604.
44
Gluesenkamp, Andrew Gallagher. "Developmental mode and adult morphology in bufonid frogs : a comparative analysis of correlated traits /." Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008336.
45
Pearson, Marianne D. "Motile Aeromonas septicaemia of farmed Rana spp." Thesis, University of Stirling, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298565.
46
Dziminski, Martin A. "The evolution of variable offspring provisioning." University of Western Australia, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0134.
Abstract:
Most theoretical models predict an optimal offspring size that maximises parental fitness. Variation in the quality of the offspring environment can result in multiple offspring size optima and therefore variation of offspring provisioning can evolve. Variation in offspring provisioning is common and found across a variety of taxa. It can be defined as between populations, explained by optimality models, or between and within individuals, neither so easily explained by optimality models. My research focused on the evolution of variable offspring provisioning by testing theoretical models relating to variation in offspring provisioning between and within individuals. Using comparative methods, I found a positive relationship between intraclutch variation in offspring provisioning and variation in the quality of the offspring environment in a suite of pond breeding frogs. This positive relationship provided evidence that patterns of variable offspring provisioning are related to the offspring environment. This study also identified a species (Crinia georgiana) with high variation in offspring provisioning on which to focus further investigations. High variation in offspring provisioning occured between and within individuals of this species independent of female phenotype and a trade-off in offspring size and number existed. In laboratory studies, increased yolk per offspring led to increased fitness per offspring. Parental fitness calculations revealed that in high quality conditions production of small more numerous offspring resulted in higher parental fitness, but in lower quality conditions the production of large offspring resulted in the highest parental fitness. This was confirmed in field experiments under natural conditions using molecular markers to trace offspring to clutches of known provisioning, allowing me to measure exact parental fitness. The strategy of high variation in offspring size within clutches can be of benefit when the future of the offspring environment is not known to the parents: as a form of bet-hedging. Further study of the offspring environment revealed that conditions such as density dependent fitness loss, spatial variation in habitat quality, and non-random offspring dispersal, can combine to create the conditions predicted by theoretical models to maintain a strategy of variable offspring provisioning in the population. My research provides a comprehensive empirical test of the theory of variable offspring provisioning
47
NGUYEN, Thien Tao. "Systematic study of the rhacophorid frogs in Vietnam." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/198931.
48
Hay, Timothy D. "Variation in advertisement call structure of whistling frogs." Thesis, University of Canterbury. Zoology, 1994. http://hdl.handle.net/10092/1517.
Abstract:
Variation in advertisement call structure of whistling frogs, Litoria ewingi, was studied among breeding sites in the vicinity of Christchurch on the East coast and Harihari on the West coast of the South Island. Males vocalized in breeding choruses throughout the year and females moved toward and appeared to evaluate calls of territorial males before initiating amplexus. Acoustic interactions between neighbours led to modification of call structure and timing, and wrestling matches between males were frequent. I quantified call structure for 1623 calls of 168 individuals using 24 call parameters. Most temporal characteristics were significantly correlated with the caller's body temperature and dominant frequency was negatively correlated with body size. These results are consistent with the prediction of temperature-dependent metabolic rates in a poikilotherm's nervous system. I compared call structure among the study populations using both multivariate and univariate analyses. Advertisement call structure showed highly significant variation among populations for most call variables. The greatest difference occurred between the West and East coast populations, and a clinal trend occurred in the East coast populations on a microgeographic scale. Variation among East coast populations in some variables was comparable to the scale of variation between coasts. These results suggest that whistling frogs exhibit natal philopatry. I obtained repeated recordings for 21 individuals and examined variation in call structure within and among individuals using nested multivariate analyses of variance. Highly significant variation occurred both within and among individuals for most call characters, but certain call characters were more variable among individuals. This suggests that whistling frog advertisement calls are individually distinctive.
49
Fouquet, Antoine. "Diversity and phylogeography of eastern Guiana Shield frogs." Thesis, University of Canterbury. School of Biological Sciences, 2008. http://hdl.handle.net/10092/2693.
Abstract:
The Guiana Shield is a sub-region of Amazonia, one of the richest areas on earth in terms of species number. It is also one of the most pristine areas and is still largely unexplored. Species number, distribution, boundaries and their evolutionary histories remain at least unclear but most of the time largely unknown. This is the case for most Anurans, a group which is recognized as threatened globally and is disappearing even from pristine tropical forests. Given the pace of forest destruction and the growing concerns about climate change it is urgently necessary to obtain a better estimate of regional biodiversity in Amazonian frogs as well as a better understanding of the origin and distribution of Anuran diversity. Furthermore, given their sensitivity to climatic conditions, amphibians are a good model to investigate the influence of paleoclimatic events on Neotropical diversification which was supposedly the driving force on biotic evolution during Pleistocene in the Guiana Shield. I first test species boundaries in two species Scinax ruber and Rhinella margaritifera. These species are widely distributed, abundant and largely recognized as species complexes. I used an original species delineation method based on the combined use of mitochondrial and nuclear DNA in phylogenetic and phylogeographic analyses. Phylogenetic analyses demonstrated the polyphyly of Scinax ruber and Rhinella margaritifera. These species consist of multiple lineages that may all merit species status. Conflicting signals of mitochondrial and nuclear markers indicated the possibility of ongoing hybridization processes. Phylogeographic analyses added further information in support of the specific status of these lineages. Our results highlight the utility of combining phylogenetic and phylogeographic methods, as well as the use of both mitochondrial and nuclear markers within one study. This approach helped to better understand the evolutionary history of taxonomically complex groups of species. The assessment of the geographic distribution of genetic diversity in tropical amphibian communities can lead to conclusions that differ strongly from prior analyses based on the occurrence of currently recognized species alone. Such studies, therefore, hold the potential to contribute to a more objective assessment of amphibian conservation priorities in tropical areas. Subsequently, I tested if these first results on cryptic species are generalisable, questioning what would potentially be a minimum estimate of the number of cryptic frog species in Amazonia and the Guiana Shield, using mtDNA with multiple complementary approaches. I also combined isolation by distance, phylogenetic analyses, and comparison of molecular distances to evaluate threshold values for the identification of candidate species among these frogs. In most cases, geographically distant populations belong to genetically highly distinct lineages that could be considered as candidate new species. This was not universal among the taxa studied and thus widespread species of Neotropical frogs really do exist, contra to previous assumptions. Moreover, the many instances of paraphyly and the wide overlap between distributions of inter- and intra-specific distances reinforce the hypothesis that many cryptic species remain to be described. In our data set, pairwise genetic distances below 0.02 are strongly correlated with geographical distances. This correlation remains statistically significant until genetic distance is 0.05, with no such relation thereafter. This suggests that for higher genetic distances allopatric and sympatric cryptic species prevail. Based on our analyses, we propose a more inclusive pairwise genetic distance of 0.03 between taxa to target lineages that could correspond to candidate species. Using this approach, we identify 129 candidate species, two-fold greater than the 60 species included in the current study. This leads to estimates of around 170 to 460 frog taxa unrecognized in Amazonia-Guianas. As a consequence the global amphibian decline detected especially in the Neotropics may be worse than realised. The Rhinella margaritifera complex is characterisized by the presence of many cryptic species throughout its wide distribution, ranging from Panama to Bolivia and almost entire Amazonia. French Guiana has long been thought to harbor two species of this group, though molecular data analysed in previous chapters indicated as many as five lineages. I tested whether morphological measurements are correlated or not with genetic data using discriminant analysis and if diagnostic characteristics among the previously determined lineages can be used to describe these new species. This is a novel integrative method which can lead to a facilitation of the description of cryptic species that have been detected by phylogenetic and/or phylogeographic studies. These analyses, combined with published data of other Rhinella species, indicated that two of these lineages represent previously unnamed species. Two of the remaining are allocable to R. margaritifera while the status of the fifth is still unclear because so far it is morphologically indistinguishable from R. castaneotica. Determining if codistributed species responded to climate change in an independent or concerted manner is a basic objective of comparative phylogeography. Species boundaries, histories, ecologies and their geographical ranges are still to be explored in the Guiana Shield. According to the refugia hypothesis this region was supposed to host a forest refugium during climatic oscillations of the Pleistocene but the causes and timing for this have been criticized. We investigated patterns of genetic structure within 18 frog species in the eastern Guiana Shield to explore species boundaries and their evolutionary history. We used mtDNA and nuclear DNA and complementary methods to compare the genetic diversity spatially and temporally. With one exception all the species studied diversified repeatedly within the eastern Guiana Shield during the last 4 million years. Instead of one Pleistocene forest refugium the Guiana Shield has probably hosted multiple refugia during late Pliocene and Pleistocene. Most of these Pleistocene refugia were probably situated on the coast of French Guiana, Amapà, Suriname and Guyana. This diversification likely resulted from forest fragmentation. Many species deserve taxonomic revisions and their ranges to be reconsidered. The local endemism of the Anuran fauna of the Guiana Shield is likely to be much higher and some areas consequently deserve more conservation efforts. Specifically I questioned whether major intraspecific diversification started before the Pleistocene and occurred within the Guiana Shield or ex situ. According to ecological characteristics of the species involved I will test different diversification hypotheses. The consequences on the diversity and the endemism of the Guiana Shield will be explored. My results demonstrate that we have been grossly underestimating local biological diversity in the Guiana Shield but also in Amazonia in general. The order of magnitude for potential species richness means that the eastern Guiana Shield hosts one of the richest frog fauna on earth. In most of the species studied high levels of mtDNA differentiation between populations call for a reassessment of the taxonomic status of what is being recognised as single species. Most species display deep divergence between eastern Guiana Shield populations and Amazonian ones. This emphasizes that the local endemism in the Guiana Shield of these zones is higher than previously recognized and must be prioritised elements taken into account in conservation planning. Nevertheless, a few other species appear widely distributed showing that widespread species do exist. This underlines the fact that some species have efficient dispersal abilities and that the frog fauna of the eastern Guiana Shield is a mixture of old Guianan endemic lineages that diversified in situ mostly during late Pliocene and Pleistocene and more recently exchanged lineages with the rest of Amazonia. Recognizing this strong historical component is necessary and timely for local conservation as these zones are likely to be irremediably modified in the near future.
50
Brunnberg, Ellen, and Karina Diatchenko. "BOILING THE FROGS SLOWLY : ACQUISITION INTEGRATION AT GEHC." Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-202586.
Abstract:
The purpose of this paper is to investigate what cultural changes can be observed in an acquired company’s corporate culture in one unit that is integrated in the acquiring company’s routines - but not physically integrated. This research aims to contribute to the understanding of post-acquisition situations in the long-term. To fulfill this purpose, the following questions were to be answered: how do the employees at the acquired (but not physically integrated) company unit experience the corporate culture seven years after the acquisition, and how do they feel knowing their unit will be transferred to the same location as the acquirer company? Answering these questions, an exploratory qualitative case study of GEHC in Uppsala was implemented with fourteen employees interviewed at GEHC Boländerna and the unit in Fyrislund. The results revealed that the culture at the acquired unit today is partly changed and the core values are no longer prominent to the same extent, despite being deliberately maintained by the employees. There is also a partly negative attitude towards the physical integration, as the last parts of the acquired company´s culture will entirely disappear as the employees will be divided into different departments once they move to Boländerna.