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Pearch, Malcolm J. "Small mammal biodiversity in Nepal". Available from the University of Aberdeen Library and Historic Collections Digital Resources. Restricted: no access until June 2, 2014, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26193.
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Wong, Dorothy L. "Public perception of mammals and mammal conservation in Fairfax County, Virginia". Fairfax, VA : George Mason University, 2009. http://hdl.handle.net/1920/4588.
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Thesis (M.S.)--George Mason University, 2009.Vita: p. 160. Thesis director: E.C.M. Parsons. Submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Science and Policy. Title from PDF t.p. (viewed Oct. 11, 2009). Includes bibliographical references (p. 152-159). Also issued in print.
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Wang, Mengdong. "Studies on IgA Induction in Intestine and Mammary Glands of Mammals". Kyoto University, 2015. http://hdl.handle.net/2433/199345.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第19021号
農博第2099号
新制||農||1030(附属図書館)
学位論文||H27||N4903(農学部図書室)
31972
京都大学大学院農学研究科応用生物科学専攻
(主査)教授 久米 新一, 教授 祝前 博明, 教授 廣岡 博之
学位規則第4条第1項該当
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Klanjšček, Tin. "Dynamic energy budgets and bioaccumulation : a model for marine mammals and marine mammal populations". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34623.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2006."June 2006."
Includes bibliographical references.
Energy intake of individuals affects growth of organisms and, therefore, populations. Persistent lipophilic toxicants acquired with the energy can bioaccumulate and harm individuals. Marine mammals are particularly vulnerable because of their large energy requirements, and transfer of energy and toxicants from mothers to their young during gestation and lactation. Dynamic energy budget (DEB) models for energy assimilation and utilization, coupled with pharmacokinetic models that calculate distribution of toxicants in individuals, can help investigate the vulnerability. In this dissertation I develop the first individual DEB model tailored specifically to marine mammals and couple it to a pharmacokinetic model for lipophilic toxicants. I adapt the individual model to the right whale and use it to analyze consequences of energy availability on individual growth, reproduction, bioaccumulation, and transfer of toxicants between generations. From the coupled model, I create an individual-based model (IBM) of a marine mammal population. I use it to investigate how interactions of food availability, exposure to toxicants, and maternal transfer of toxicants affect populations. I also present a method to create matrix population models from a general DEB model to alleviate some of the drawbacks of the IBM approach.
by Tin Klanjšček.
Ph.D.
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Olsen, Morten Tange. "Molecular ecology of marine mammals". Doctoral thesis, Stockholms universitet, Institutionen för genetik, mikrobiologi och toxikologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-71166.
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Marine mammals comprise a paraphyletic group of species whose current abundance and distribution has been greatly shaped by past environmental changes and anthropogenic impacts. This thesis describes molecular ecological approaches to answer questions regarding habitat requirements, genetic differentiation, and life-history trade-offs in three species of marine mammals. The annual sea-ice dynamics of the Arctic may have large effects on the abundance and distribution of Arctic species such as the pagophilic ringed seal (Pusa hispida). Paper I describes and applies a simple molecular method for isolating and characterizing a relatively large set of single nucleotide polymorphisms (SNPs) in the ringed seal. These SNPs have been genotyped in a yet-to-be-analysed dataset which will form the basis in an assessment of the micro-evolutionary effects of annual sea-ice dynamics on ringed seal. Current management efforts directed towards the North Atlantic fin whale (Balaenoptera physalus) are hampered by an unclear understanding of population structure. Paper II investigates the DNA basis for the high levels of genetic differentiation that have been reported in allozyme studies of the North Atlantic fin whale. We find that additional processes (at the organismal level) may have contributed to shaping the phenotype of the underlying allozyme variation. Telomeres may potentially serve as markers for determining the chronological and biological age of animals where other means of inference is difficult. Paper III describes the application and evaluation of four qPCR assays for telomere length estimation in humpback whales (Megaptera novaeangliae), finding that reliable telomere length estimates require extensive quality control. Paper IV applies the best performing qPCR assay to test whether telomeres may provide a method for genetic determination of chronological age in whales and concludes that the biological and experimental variation in telomere length estimates is too large to determine age with sufficient resolution. Finally, because telomere length and rate of telomere loss also may be affected by other cellular and organismal processes, such as resource allocation among self-maintenance mechanisms, growth and reproduction, Paper V describes the correlations between individual telomere length and rate of telomere loss, and sex, maturity status and female reproductive output. We found that the costs of reproduction in terms of telomere loss are higher in mature humpback whales than in juveniles; that reproductive costs are higher in males than females; and that differences among females tend to correlate with reproductive output.At the time of doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Submitted; Paper 3:Submitted; Paper 4: Manuscript; Paper 5:Manuscript
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Osborn, Scott Donald. "Adaptive heterothermy in desert mammals". Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185449.
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Endothermic homeothermy is a major feature of the adaptive suites of tachymetabolic animals such as mammals and birds. The advantages homeothermy confers on birds and mammals include relative independence from the environment, a stable internal milieu, and possibly the ability to sustain high aerobic activity (Bennett and Ruben 1979). Some mammals in situations of limited water or energy availability, however, depart markedly from homeothermy and instead display patterns of heterothermy. Torpor is a lowering of body temperature (T(b)) to conserve energy and/or water. I studied the energetics of arousal from torpor in two desert pocket mice species. The species differed in warming rates and arousal durations, but used similar amounts of energy to arouse. The smaller species, Perognathus amplus, lost mass more quickly while fasting in the cold, yet waited as long as the larger species, Chaetodipus baileyi, before entering torpor. P. amplus maintained a lower T(b) during topor than C. baileyi. The thermodynamics of arousal indicated that metabolic rate during arousal was a function of T(b) but not ambient temperature (Tₐ), that the animals changed thermal conductance to increase heat gain when Tₐ was greater than T(b), and that Q₁₀ decreased during arousals. In contrast to torpor, adaptive hyperthermia provides desert mammals in dry, hot environments a means to conserve water that would normally be used for evaporative cooling. I modeled the effects of body size on adaptive hyperthermia and discovered that small mammals gain the most in terms of water savings using this strategy, and that small and large mammals can spend larger fractions of the day active than do medium size mammals. I demonstrated that two desert ground squirrel species make use of adaptive hyperthermia during the summer near Tucson, Arizona by following free-ranging squirrels implanted with temperature-sensitive radio transmitters. Ground squirrel T(b) fluctuated almost continuously, ranging from about 35°C to over 42°C, and rarely approached steady state. Of the two species studied, Ammospermophilus harrisii had higher mean T(b), similar maximum T(b), and lower T(b) variability compared to Spermophilus tereticaudus. These results are consistent with the more wide-ranging foraging style of A. harrisii compared to S. tereticaudus.
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Mamone, Mario Salvatore. "A comparative study of small mammal communities in riparian and upland mixed-conifer forest habitats /". View full-text version online through Southern Oregon Digital Archives, 1994. http://soda.sou.edu/awdata/040308a1.pdf.
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Thesis (M.S.)--Southern Oregon State College, 1994.Typescript. Includes bibliographical references (leaves 73-80). Also available via Internet as PDF file through Southern Oregon Digital Archives: http://soda.sou.edu. Search Bioregion Collection.
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Nousch, Marco Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "The role of the translational regulator p97 in mammalian cells". Awarded by:University of New South Wales. Biotechnology & Biomolecular Sciences, 2008. http://handle.unsw.edu.au/1959.4/41445.
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Members of the eukaryotic initiation factor 4G (eIF4G) family play a central role in the translation initiation process. One member of this family is p97 (also called DAP5 and NAT1), a protein that is highly homologous to the C-terminal two thirds of eIF4G. Overexpression studies suggested that p97 is a pure translational repressor that has to be cleaved into a shorter form called p86, in order to show translational activity. In this study a series of experiments indicated that full length p97 has a number elF property such as association with active translating ribosomes, stimulatory effects in the Direct Initiation Factor assay and accumulation in stress granules. Additionally the endogenous p97 complex was isolated from HeLa cells and mRNA as well as the protein components were characterized. P97 associated mRNAs were described by a custom made 5'UTR focus array, showing that the protein binds to a broad range of mRNA. The relative lack of mRNA specificity argues for a general role of p97 in translation, which does not seems to be essential in unchallenged cells, because a down regulation of p97 protein levels has no effect on the translational status of the bulk of mRNAs. Mass spectrometry analysis revealed a novel protein-protein interaction between p97 and DNA methyltransferase 1 (Dnmt1), which does not rely on a nucleic acid. For this interaction the C- and N-terminus of p97 play a critical role. Further, Dnmt1 has the ability to interact with elF4G and the small ribosomal subunit, which might provide evidence for a novel function of Dnmt1 in RNA metabolism.
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Fraser, Sheena Mary. "Mammals in Late Neolithic Orkney (with reference to mammal bone recovered from Links of Noltland, Westray)". Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/26007.
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Excavation of thirty skulls, twenty-eight cattle and two sheep from the foundation course of a Late Neolithic structure at Links of Noltland (LON), Structure 9, is the starting point for this thesis, which investigates the economic and socio-cultural relationships of cattle and other mammals on Orkney communities between 3000 and 2500 BC. The LON settlement was located on a machair plain in Westray, the most N-W island within the Orkney archipelago (HY 428 493). Male and female cattle skulls were inter-mixed within the LON foundation course so a “bull cult” is not represented. The sequence from living skulls to skulls “animating the building is (i) breed/acquire (ii) nurture (iii) cull/butcher (iv) consume (v) transform to object (vi) curate (vii) deposit. A skull deposit infilling an internal passageway from another LON, Structure 18, is compared and contrasted with the Structure 9 foundation deposit. Special treatment of cattle skulls from a wide range of European and Near-East sites is also reviewed to emphasise the widespread use of this symbol during the Neolithic period. Orkney was separated from mainland Scotland prior to the establishment of the LON settlement so consideration is given to modes of arrival for mammals and their impact on this depauperate archipelago. Cattle and sheep dominated the domestic mammal remains examined, pig and dog were rare and goat and horse absent. The most abundant non-domestic mammals were red deer and Orkney voles, but otters and sea mammals were also present in low numbers. Genetic studies indicate that one cattle skull carried genetic material from aurochs, wild cattle. To date there is sparse evidence of interbreeding between wild aurochs and Neolithic domesticated cattle in Europe and none in Britain. The alterative explanation that aurochs were already present on Orkney during the Neolithic is explored. Articulated red deer deposits from LON were also examined. Although previous publications explored the possibility that these deposits are “ritual” other possible explanations for these deposits are outlined. No parallels were noted between the cattle skull and articulated red deer deposits, but the importance of antler for practical and symbolic use in Neolithic Orkney may be under-estimated. Stature of cattle remained relatively stable during the Mid to Late Neolithic in Orkney but underwent diminution by the Iron Age. A similar, but less marked reduction was also noted for sheep, but red deer already had small stature compared with early Holocene mainland Scotland red deer. The thesis concludes that cattle, sheep and red deer were of fundamental importance to the Neolithic society of Orkney, providing surplus food, tools and possibly traction, to support an increasingly sophisticated Neolithic society undertaking construction of complex structures and monuments. In addition, cattle fulfilled an important role in their cultural and spiritual life.
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Liu, Yang Bankaitis Vytas A. "The Sac1 phosphoinositide phosphatases in mammals". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2847.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2009.Title from electronic title page (viewed Jun. 4, 2010). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Cell and Developmental Biology." Discipline: Cell and Developmental Biology; Department/School: Medicine.
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Keith, Mark. "Conservation assessment of South African mammals". Thesis, Connect to this title online, 2005. http://upetd.up.ac.za/thesis/available/etd-02142006-162024/.
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Aung, Hnin Thanda. "The importance of epigenetics in mammals /". [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19398.pdf.
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Mathis, Alexander. "The representation of space in mammals". Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-150029.
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Northridge, Simon Patrick. "Interactions between fisheries and marine mammals". Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46474.
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Thomson, Gabrielle Anne Biotechnology & Biomolecular Sciences Faculty of Science UNSW. "Retroelements as controlling elements in mammals". Awarded by:University of New South Wales. Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/26203.
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Retroelements are genomic parasites which make up ~42% of the human genome and 38% of the mouse genome. Most are degenerate, but a large number have relatively intact promoter elements, suggesting that they are capable of transcription. Transcriptionally active retroelements can perturb normal transcription units in their vicinity through a variety of mechanisms, leading to phenotypic effects and in some cases disease. This phenomenon of transcriptional interference has been observed in organisms as diverse as maize, Drosophila, and the mouse. We analysed the extent of retroelement transcription in normal and diseased tissues, by searching the mouse and human EST databases for transcripts originating in retroelement promoters, and found a large number of transcripts from LINEs, SINEs and ERVs. Retroelement transcripts were found to be initiated in both sense and antisense orientations, and to be equally as common in normal and diseased tissue. Several of these transcripts were chimeric, appearing to initiate in retroelements and reading through to cellular genes, suggestive of transcriptional interference. We have used transposon display to identify and recover retroelement transcripts in the mouse. Transcripts initiated in LINE, SINE and ERV promoters are numerous, and many are chimeric with cellular genes. Although the numbers of recovered chimeric transcripts are too large to permit rigorous analysis of more than a small proportion, some of those we have studied further appear to be authentic transcripts that may represent interference with the canonical promoters of the genes in question. Our results suggest that transcriptional interference by retroelements may be a relatively common occurrence in mammals.
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South, Andrew Brian. "Modelling the spatial distribution of mammals". Thesis, University of Newcastle Upon Tyne, 1999. http://hdl.handle.net/10443/175.
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In this thesis I outline the different processes, operating at different scales, that influence the spatial distribution of mammals and review modelling approaches that have been used to represent these processes. I investigate the application of a selection of modelling approaches operating at different scales. A model based on the energetics and movements of individual foragers was developed to investigate population spacing patterns and applied to the red squirrel. At high food densities, small, similarly sized, non overlapping ranges were generated, whereas at low food densities ranges were larger, more overlapping and more variable in size. The model is a first step towards investigating the spacing patterns of ranging mammals. A model representing the positioning of dens was applied to predict the distribution of badger main setts. The model determined how many setts could be placed in suitable habitats while maintaining a pre-defined, minimum inter-sett distance. The representation of badger spacing behaviour and the utility of the approach is discussed. At a larger scale, a model based upon births and deaths within habitat patches and an explicit representation of dispersal between patches was used to assess plans to reintroduce the beaver. It predicted little or no population spread, in contrast to the application of a generic population viability analysis package that predicted rapid population spread. A difference in the representation of dispersal was identified as the most likely cause of the disparity. A general model based on these approaches was developed to investigate the interaction between dispersal and demographic processesing spatially explicit population models. The future of models to predict the spatial distribution of mammals is discussed in relation to issues of scale, management applications and modelling philosophies.
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Waddell, Victor Garry. "Higher level molecular systematics of mammals". Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394601.
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Wragg, Fiona Catherine. "Biodiversity and conservation of African mammals". Thesis, Leeds Beckett University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401768.
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Hobson, L. "Dispersal and reproductive competition in mammals". Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3005820/.
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Zartman, David L. "INTRAVAGINAL TEMPERATURE TELEMETRY IN FEMALE MAMMALS". International Foundation for Telemetering, 1986. http://hdl.handle.net/10150/615280.
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International Telemetering Conference Proceedings / October 13-16, 1986 / Riviera Hotel, Las Vegas, NevadaThe four major management problems in female farm animals are identification, breeding timeliness, health monitoring and notice of parturition (delivery of young). Each of these has been solved with a single temperature-sensitive device placed in the vagina nonsurgically with a nylon anchor. Remote sensing of deep-body (core) temperature in female livestock is a major breakthrough in husbandry of farm animals and important zoo animals. Development of a patented, vaginal radio implant has enabled the remote sensing and automated processing of animal temperature data for females. A natural component of the system is automated identification of each female wearing a transmitter. The methodology of collecting and interpreting deep-body temperature depends upon using each female as her own basis of comparison. A temperature deviation of greater than 0.4* C relative to the average of the previous five day’s temperatures taken at approximately the same time of day indicates a significant physiological event. Ultimately, the optimum configuration of this system will invoke the creation of artificial intelligence or, at least, an expert system.
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Belgard, Tildon Grant. "Comparative neurotranscriptomics in mammals and birds". Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:932c796c-d219-4df3-85cc-7d9db19d7d6b.
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In this thesis I apply new sequencing technologies and analytical methods derived from genomics and computer science to the neuroanatomy of gene expression. The first project explores characteristics of gene expression across adult neocortical layers in a representative mammal – the mouse. Amongst the thousands of genes and transcripts differentially expressed across layers, I found common functional characteristics of genes that define certain layers, candidate cases of isoform switching, and over a thousand apparent long intergenic non-coding RNA transcripts. The second project compares patterns of gene expression in the structurally diverged adult derivatives of the pallium in mice and chickens. Overall, gene expression levels were moderately correlated between the two species. While expression patterns of ‘marker’ genes were only poorly conserved in these regions, there nevertheless was significant conservation of cross-species marker genes for homologous structures, cell types and functionally analogous regions. Many aspects of these data from both projects can now be easily browsed and searched from custom-built web interfaces. In addition to generating unprecedented genome-wide resources for the neuroscience community to explore the functional and structural dimensions of gene expression amongst different pallial regions in mammals and birds, this work also provides new insights into the widespread evolutionary shuffling of adult marker gene expression.
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Candille, Sophie Isabelle. "Genetics of pigmentation patterning in mammals /". May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Flewelling, Leanne J. "Vectors of brevetoxins to marine mammals". [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002675.
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Halliday, T. J. D. "The enigmatic evolutionary relationships of Palaeocene mammals and their relevance for the Tertiary radiation of placental mammals". Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1469745/.
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Understanding the general pattern of how a clade evolves over time is a central aim of palaeontology and evolutionary biology. The observation that the tree of life is asymmetric in species distribution necessitates that rates of evolution, speciation, and extinction vary through time and across phylogeny. The way this variation is distributed can help to inform on historic events, selection pressures, and relationships. Often, at the origination of a clade, it is supposed that there is an ‘early burst’ of diversification, before rates of speciation and morphological evolution slow down as the clade ages. One example of a supposed ‘early burst’ is that of placental mammals, but the internal relationships of the earliest members of this group have prevented further study of macroevolutionary parameters. In this thesis, by building the largest cladistic data matrix to date, I test the relationships of mammals from the earliest Cenozoic, and from the resulting phylogenies, test the hypotheses that the end-Cretaceous mass extinction resulted in an adaptive radiation of placental mammals. I show that Phenacodontidae are most parsimoniously ancestral to Perissodactyla, that a division between Boreoeutheria and Atlantogenata is better supported than one between Xenarthra and Epitheria or Afrotheria and Exafroplacentalia at the root of Placentalia, and that all “condylarths” can be placed, with varying degrees of confidence, as stem members of laurasiatherian orders. I show that there was an increase in rate of morphological evolution immediately after the end-Cretaceous mass extinction, that Placentalia is extremely likely to have originated less than 70 million years ago, and that the rise of Placentalia was associated with an increase in morphospace occupation, and, with a lag, mean pairwise dissimilarity of taxa. These conclusions support the contention that the end-Cretaceous mass extinction was not just an important time in Earth’s ecological history, but crucial to the diversification of mammals to the level observed today.
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McCaslin, Lauren E. "Documenting Marine Mammal Behavior and Evaluating the Benefits and Consequences of Viewing Marine Mammals in Southcentral Alaska". TopSCHOLAR®, 2019. https://digitalcommons.wku.edu/theses/3128.
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Marine mammals are in a precarious conservation position because of anthropogenic impacts and historic perceptions that they are a consumable commodity. In light of changing abiotic conditions, further evaluation is needed on the habitat use, behavior, and interactions among marine mammals. Conservation legislation has helped protect species, but the greatest ground swelling may be the advent of the commercial whale watching industry. The feeding grounds in Alaskan waters have made this area a prime tourism location, and these nutrient-rich waters have resulted in a confluence of marine mammal species, including the appealing and abundant humpback whale (Megaptera novaeangliae) that may associate with three ecotypes of killer whales (Orcinus orca). These species are interesting because they may travel together to feed on prey or be adversaries in a predator-prey relationship. Using whale watching as a platform, this study evaluated the effects of the presence of these two species separately and together, and of the type of interaction between them, on human perception. Data were collected via opportunistic observations and a retrospective pre- and post-survey instrument. Differences in humpback whale distribution and group size patterns were found relative to killer whale occurrence, although humpback whale behavioral states were unchanged. Changes in passenger conservation attitudes could not be attributed to species and behaviors but they were important determinates to whale watching satisfaction. Overall, more positive conservation attitudes and an increase in knowledge about marine mammals were reported after whale watching. These tours provide an opportunity for collecting meaningful scientific data and providing more in-depth education such as enhancing the appreciation for ecosystem services provided by marine mammals.
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Xu, Xiufeng. "Studies of mammalian mitochondrial genomes with special emphasis on the perissodactyla". Lund : Lund University, 1996. http://catalog.hathitrust.org/api/volumes/oclc/38161173.html.
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Martínez, Marchal Ana. "Regulation of the oocyte pool in mammals". Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667797.
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Durant la oogènesi dels mamífers, les oogònies proliferen forman els anomenats cists. Les oogònies entren en meiosis progressant en la profase I i els cists es trenquen al mateix temps que es produeix una mort massiva perinatal dels oòcits. En la profase I, s’indueixen trencaments de doble cadena (DSBs) per tot el genoma, que son reparats per recombinació homòloga per a promoure la sinapsi dels cromosomes homòlegs. Existeixen diferents mecanismes que s’activen en resposta a errors en aquests processos i que aturen el cicle cel·lular i produeixen l’apoptosi de les cèl·lules danyades. La resposta al dany al DNA (DDR) es activada en presència d’oòcits i d’espermatòcits amb errors de recombinació en l’anomenat checkpoint de recombinació. Per l’altre banda, errors en la sinapsi activen el checkpoint de sinapsi. El nostre objectiu era caracteritzar les funcions de la DDR i del checkpoint de sinapsi durant l’oogènesi en mamífers. Contràriament al que succeeix en espermatòcits, els oòcits presenten un alt número de DSBs no reparats a l’estadi de paquitè en el moment en que es produeix la mort oocitària massiva i el trencament del cists. Per tal d’esbrinar si el checkpoint de recombinació participa en la regulació del número d’oòcits en mamífers, hem analitzat el número de DSBs, el número d’oòcits en femelles perinatals i adultes, el trencament dels cists, la formació de fol·licles i la vida reproductiva de femelles de ratolí control i mutants per a la quinasa efectora de la via de la DDR, la proteïna CHK2. Les nostres dades han revelat la implicació de CHK2 en la regulació del número d’oòcits, però només en ovaris fetals, obrint la possibilitat de l’existència d’una via alternativa regulant el número d’oòcits després del naixement. Els nostres estudis utilitzant ovaris cultivats in vitro en presència d’inhibidors, suggereixen que CHK1 podria compensar l’absència de CHK2 in vivo. Per tant, la via de la DDR controlaria el número d’oòcits en mamífers. A més, hem trobat un augment del número d’oòcits en adultes velles mutants per CHK2 suggerint que la DDR controla la llargada de la vida reproductiva en mamífers. Finalment, hem estudiat el possible paper de TRIP13 en el checkpoint de sinapsi. La proteïna TRIP13 es necessària per a la recombinació, però també per a la sinapsi dels cromosomes sexuals i per a la formació de la vesícula sexual, suggerint un possible rol al checkpoint de sinapsi. Hem analitzat el número d’oòcits en ovaris Spo11-/- Trip13mod/mod i Dmc1-/- Chk2-/- Trip13mod/mod per a esbrinar si TRIP13 es necessària per a activar el checkpoint de sinapsi en femelles. Les nostres dades han revelat un rescat en el número d’oòcits en el triple mutant, però no en el doble. Aquest resultats obren la possibilitat de que TRIP13 participi en el checkpoint de sinapsis, però com a alternativa, proposem que aquesta participació podria ser compatible amb una possible regulació per part de TRIP13 de la elecció de la via de reparació dels DSBs.During mammalian oogenesis, oogonia proliferate forming the so-called cysts. The oogonia enter meiosis progressing through prophase I and the cysts break down concomitantly to massive perinatal oocyte death. During meiotic prophase I, double strand breaks (DSBs) are induced throughout the genome and repaired by homologous recombination to promote the synapsis of the homologous chromosomes. In response to errors in these processes, different response pathways are activated triggering cell cycle arrest or even apoptosis. The DNA damage response (DDR) is activated in response of meiocytes with recombination failure in the recombination checkpoint; while errors in synapsis trigger the synapsis checkpoint. We aimed to characterize the roles of the DDR and synapsis checkpoint in mammalian oogenesis. Contrary to what occurs in spermatocytes, oocytes present high numbers of unrepaired DSBs at pachynema, at the time of the massive oocyte death and cyst breakdown. In order to know if the recombination checkpoint participates in the regulation of the oocyte number in mammals, we analyzed the presence of DSBs, the oocyte number in both perinatal and adult females, the cyst breakdown, the formation of follicles and the reproductive lifespan using control and mutant mice for the effector kinase of the DNA damage response pathway, CHK2. Our data revealed the involvement of CHK2 in the regulation of the oocyte number but only in fetal ovaries prior to birth, raising the question of a possible alternative regulator acting just after birth. Our studies using in vitro ovarian cultures using inhibitors, suggest that CHK1 may compensate the loss of CHK2 perinatally in vivo. Thus, revealing that the DDR pathway controls the oocyte number in mammals. Furthermore, we found an increased number of oocytes in elder Chk2 mutant females suggesting that the DDR controls the reproductive lifespan extension in mammals. Finally, we studied the possible involvement of TRIP13 in the synapsis checkpoint. The protein TRIP13 is required for recombination, but it is also needed for the synapsis of sex chromosomes and the sex body formation. Thus, suggesting a possible role in the synapsis checkpoint. We analyzed the oocyte number in females from Spo11-/- Trip13mod/mod and Dmc1-/- Chk2-/- Trip13mod/mod ovaries in order to infer if TRIP13 is required to implement the synapsis checkpoint in females. Our data revealed a rescue in the number of oocytes in the triple mutant, but not in the double mutant. These results leave open the possibility of a participation of TRIP13 in the synapsis checkpoint, but as an alternative, they could be compatible with a possible role of TRIP13 regulating the DSB repair pathway choice.
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Carter, Caroline Jane. "Tidal energy, underwater noise & marine mammals". Thesis, University of the Highlands and Islands, 2008. https://pure.uhi.ac.uk/portal/en/studentthesis/tidal-energy-underwater-noise-and-marine-mammals(9963d662-76e1-4e70-a3ac-e18a96b23101).html.
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Sourcing energy from renewable sources is currently a key theme in modern society. Consequently, the pace of development of these emerging technologies is likely to increase in the near future, particularly in marine renewables. However, the environmental and ecological impact of many of these new developments in the marine environment is largely unknown. My thesis has focused on one unknown area of interaction; the potential effect of tidal-stream devices on marine mammals. Collision risk is often cited as a key concern. Therefore, my premise was - for marine mammals to avoid a collision with a marine renewable device (assuming they are on a collision course) they must first detect the device. It is well understood that marine mammals use sound and hearing as their primary sense for communication, foraging, navigation and predator avoidance, so it is highly likely that the primary cue for device detection will be acoustic. However, it is not known how operational marine renewable devices might modify the acoustic landscape in these areas, or whether they will be audible to marine mammals in time to alert them to the presence of devices. It has been suggested that the high level of natural and anthropogenic background noise in tidal-stream areas may mask (drown out) the signal of the tidal devices. The acoustic characteristics of underwater noise in shallow coastal waters are currently not well known. My thesis adds data to this knowledge gap by measuring and mapping underwater noise levels in tidal-stream areas.
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Zadissa, Amonida, i n/a. "Inferring transcriptional regulation in mammals using bioinformatics". University of Otago. Department of Biochemistry, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070614.111340.
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Gene expression and its regulation is a highly coordinated system, involved in many biological processes such as cell growth, division and differentiation. Transcriptional regions, involved in gene regulation, consist of a heterogeneous collection of smaller regulatory elements. In some cases, co-regulated genes contain a common set of transcription factor binding sites (TFBS).
Analysis of promoter regions is the major approach in understanding the transcriptional regulatory mechanisms. It is also useful for interpretation of mammalian gene expression studies, where co-expressed genes may share motifs representing putative TFBS. Motif identification also has the advantage that it can predict control regions in genes that have not been measured experimentally. However, a common problem is incomplete genomic sequence for the experimental species of interest. The approach here is to identify and use orthologous gene promoter sequences from a related and well-characterised species.
The primary aim of this study was to identify and predict regulatory TFBS in species where promoter sequence does not exist or is incomplete. The MEME programme was employed for the motif prediction step. The predicted elements were subsequently compared to known TFBS using TRANSFAC and JASPAR databases for identification. A methodology based on relative entropy was used. The validity of the method was confirmed as the predicted motifs in the training set were the expected sites involved in regulation of muscle development. The technique was applied to two data sets, generated from expressed sequence tag (EST) clustering analysis and microarray experiments. All data sets, software and results are available on the accompanying CD.
Bovine expression data was analysed for cardiac-specific expression using two separate approaches, combining bovine library EST frequency and human gene expression ratios. For each approach, the orthologous human and bovine promoter sequences were analysed for common motifs. Across all comparisons, 37% of motifs were identified as known TFBS using the TRANSFAC and JASPAR databases. As the human comparison had more promoter sequences available, this was the main limiting factor for the corresponding bovine analysis, rather than cross-species divergence or accuracy of gene expression measurement. Results from this study demonstrate that using promoter sequences from a related species is a viable approach when studying gene expression in species with limited amount of genomic sequence. As the bovine genome becomes more complete, it can in turn serve as the reference genome for other agriculturally important ruminants, such as sheep, goat and deer.
The second application concerned in silico analysis of gene regulation patterns in response to stimuli. Recently it has been shown that a mutation in the bone morphogenetic receptor IB leads to an increased ovulation rate in sheep. The objective of this study was to analyse gene expression patterns in cultured cells in response to four members of the BMP family, i.e. BMP2, BMP4, BMP6 and BMP7 and the control TGFβ. Microarray data was provided by J. Young. Twelve highly upregulated genes were stimulated by all BMPs, seven of which are known BMP target genes. Analysis of the predicted motifs identified four elements that may be involved in the regulation process. Cross-species comparison for one of the genes, ID1, showed high conservation of one of the motifs across 11 mammalian genomes. This particular motif had not been identified as a known binding site. In summary, the analysis of the expression data suggest an extension of the list of BMP targets.
The proposed method is relatively robust when sufficiently co-expressed (co-regulated) sequences can be identified, whether from the same or another species.
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Scott, Craig Smith. "Middle Paleocene mammals from Calgary, Alberta, Canada". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60494.pdf.
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Lucke, Klaus [Verfasser]. "Auditory studies on marine mammals / Klaus Lucke". Kiel : Universitätsbibliothek Kiel, 2009. http://d-nb.info/1019811455/34.
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Reid, Ian Duncan. "Transcription factor binding site turnover in mammals". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18293.
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Transcription factor binding sites (TFBS) are usually, but not always, conserved during evolution. To better understand TFBS evolution I examined the cases of non-conservation for 1120 known human and mouse TFBS in the genomes of 11 mammals and the reconstructed genomes of their ancestors. Novel TFBS appeared frequently, even near conserved ancestral sites, but site gain was significantly more probable when an ancestral site was lost (TFBS turnover). 165 human TFBS and 113 mouse TFBS have evolved de novo since divergence from the boreoeutherian ancestor and are absent in other lineages. Putative TFBS and sequences that differ from TFBS by one substitution are more abundant near known TFBS than expected by chance. Apparent enrichment and clustering of weak TFBS result from local variations in CG frequency.Les sites de fixation des facteurs de transcription (TFBS) sont souvent, mais pas toujours, conservés pendant l'évolution. Afin de mieux comprendre leur évolution, j'ai examiné les cas de non-conservation de 1120 TFBS connus chez l'homme et la souris dans les génomes d'onze mammifères et les génomes reconstruits de leurs ancêtres. De nouveaux TFBS se sont développés fréquemment, même près des sites ancestraux conservés, mais le gain d'un site était significativement plus probable quand un site ancestral avait disparu. 165 TFBS de l'homme et 113 TFBS de la souris ont évolué de novo depuis leur divergence de l'ancêtre boreoeuthérien et sont absents des autres lignées. Les TFBS putatifs et les séquences qui diffèrent des TFBS par une substitution sont plus abondants qu'attendu par hasard auprès des TFBS connus. L'enrichissement et rassemblement apparents des TFBS faibles sont des résultats des variations locales dans l'abondance de C et G.
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Thompson, Amy. "Correlates and consequences of heterothermy in mammals". Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107856.
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Endotherms are capable of using internal heat to precisely regulate body temperature at an elevated level, yet there is considerable variation in the range of body temperatures (heterothermy) expressed by an endotherm. In this thesis, I exploit two different approaches to address the causes and consequences of heterothermy in mammals, reflective of an underlying trade-off between the functional benefits and energetic costs of endothermy. I first conduct an inter-specific, empirical analysis of mammalian body temperatures reported in the literature, treating heterothermy as a continuous variable spanning all endotherms, to examine factors that predict the degree of body temperature fluctuation observed in different species. Across mammals, body temperature variation decreased with body mass and increased with proximity to the poles, and food hoarders were less heterothermic than non-hoarders. Further, with these allometric, latitudinal, and behavioural effects included, phylogeny still had a strong influence on the degree of body temperature variation in a given species. In my second chapter, I examine potential behavioural consequences of torpor, a special case of heterothermy involving a pronounced reduction in body temperature and metabolism. This research was conducted in captivity on eastern chipmunks (Tamias striatus), which exhibit deep torpor and show extreme individual variation in heterothermy that spans most of the heterothermic continuum expressed by mammals in general. To test the hypothesis that torpor impairs exploration and spatial memory, individual performance was assessed in an open field and a radial arm maze prior to and during hibernation. Results showed that habituation in the open field was negatively impacted by torpor, particularly prolonged torpor, however performance in the radial maze, tested later in the arousal period, was less affected. Thus, torpor expression clearly affects behaviour, but these effects are very transient and therefore unlikely to have long-term fitness consequences. Mammals overall are characterized by extensive variability, both among and within species, in the degree of body temperature variation, with species occupying cold climates and relying on ephemeral food being characterized by the most heterothermy. As to why more individuals and species do not exploit the energetic savings of high-amplitude heterothermy, captive research suggests the immediate costs of reduced body temperature on endotherm function may be more important than its long-term effects.Les animaux endothermiques sont capables d'utiliser leur chaleur interne afin de réguler précisément leur température corporelle à un niveau élevé, pourtant il y une gamme considérable dans le degré de variation en température corporelle (hétérothermie) chez les endothermes. Dans cette thèse, j'utilise deux méthodes différentes pour adresser les causes et conséquences de l'hétérothermie chez les mammifères, reflétant un compromis entre les avantages fonctionnels et les désavantages énergétiques de l'endothermie. Je mène premièrement une analyse empirique inter-espèce de l'hétérothermie chez les mammifères rapportée dans la littérature. L'hétérothermie est considérée comme trait continu pour examiner les facteurs qui prédisent le gradient hétérothermique chez 545 espèces. L'hétérothermie diminue avec la masse corporelle et augmente vers les pôles, et les amasseurs de nourriture sont moins hétérothermiques que les non-ammasseurs. Une fois que ces effets allométriques, latitudinaux, et comportementaux sont inclus, la phylogénie avait encore une influence forte sur le degré d' hétérothermie. Dans mon deuxième chapitre, j'examine les désavantages comportementaux de la torpeur, un cas spécial d'hétérothermie dans lequel les individus montrent une réduction marquée de leur température corporelle et de leur métabolisme. Cette recherche a été menée en captivité sur les tamias rayés (Tamias striatus), reconnus pour manifester des degrés de torpeur traversant la plupart de la gamme d'hétérothermie exprimée par les mammifères en générale. Pour examiner les désavantages comportementaux de la torpeur comme une explication potentielle de cette variation, la performance individuelle a été évaluée avant et durant l'hibernation à l'aide d'un test de l'arène et d'un test de labyrinthe radial. Les résultats ont montré que l'habituation dans le test de l'arène était affectée négativement par la torpeur, particulièrement la torpeur profonde, mais la performance dans le labyrinthe radiale, testée plus tard dans la période d'éveil, était moins affectée. Ainsi, l'expression de la torpeur affecte clairement le comportement, mais ces effets sont très transitoires et ont alors probablement peu de conséquences à long terme sur l'aptitude de l'individu. Les mammifères en générale sont caractérisés par une vaste variation, inter- et intra-espèce, dans le degré d'hétérothermie et les espèces occupants les climats froids et se nourrissants de ressources éphémères sont caractérisées par le plus d'hétérothermie. En expliquant pourquoi il n'y a pas plus d'individus et d'espèces qui exploitent les avantages énergétiques de l'hétérothermie de haute amplitude, la recherche en captivité suggère que les désavantages immédiats de la torpeur sur la fonction des endothermes peuvent être plus importants que ses effets à long terme.
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Poirier, Madeleine. "The expression of CDP/Cux in mammals /". Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79114.
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Knowing the tissues, cells, and sub-cellular compartments where a protein is expressed can provide important insights about its biological and physiological roles. CDP/Cux is a transcription factor that is proteolytic processed as cells progress from G1 to S phase of the cell cycle. With the aim of investigating CDP/Cux expression in tissues and in tissue culture cells, I characterized a panel of polyclonal and monoclonal antibodies raised against various regions of the protein. I established an immunohistochemistry assay and demonstrated that CDP/Cux is expressed in certain epithelial cells in several tissues. Using the technique of immunofluorescence I studied the localization of CDP/Cux proteins throughout the cell cycle. I obtained results suggesting that CDP/Cux isoforms may localize to different compartments during S phase. Finally, using 3 different antibodies, I showed that cathepsin L, the potential protease that cleaves CDP/Cux, may translocate to the nucleus during progression through the cell cycle.
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Barker, Emily Ngaire. "Molecular studies on haemotropic mycoplasmas of mammals". Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539767.
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Mohamed, H. A. "Studies on protozoan parasites of small mammals". Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374504.
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Merkin, Jason Jay. "The evolution of mRNA splicing in mammals". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/89945.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2014.Title as it appears in MIT commencement exercises program, June 6, 2014: The evolution of mRNA splicing in mammalian tissues Cataloged from PDF version of thesis.
Includes bibliographical references (pages 167-172).
In this thesis, I describe investigations into the evolution of splicing in mammals. I first investigate a small class of alternative splicing events, tandem splice sites, and show how they are used to introduce and remove coding sequence in a species-specific manner. I then describe the generation and analysis of a large RNA-seq dataset from 9 matched tissues in 5 species, with the aim to investigate the evolution of splicing in mammals. I first investigate the evolution of exons that predate the most ancient divergence of species studied, finding that their splicing is frequently poorly conserved. For a subset of these exons, I identify unique regulatory properties and provide evidence linking alternative splicing to phosphorylation potential of proteins. I then consider sources of novel exons, in these species. I use these and other published data to identify one way in which splicing of novel exons impacts the biology of the cell. I also present evidence implicating genomic indels in exon creation and splicing variation.
by Jason Jay Merkin.
Ph. D.
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Guttman, Mitchell. "Functional large non-coding RNAs in mammals". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/72806.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references.
It is now clear that RNA is more than a messenger and performs vast and diverse functions. These functional RNAs include the ribosomal, transfer, and splicing-associated RNAs along with a cast of tiny RNAs, including microRNAs and other families. In addition to these classic examples, there were a handful of known functional large ncRNAs that play important biological roles. To identify additional functional large ncRNAs we exploited a chromatin signature of actively transcribed genes to define discrete transcriptional units that do not overlap any known proteincoding genes. Using this approach we identified -3,500 transcriptional units in the human and mouse genomes that produce multi-exonic RNAs that lack any coding potential. We termed these large intergenic non-coding RNAs (lincRNAs). Importantly, these lincRNAs exhibit strong purifying selection across various mammalian genomes. To determine whether the lincRNA transcripts themselves have biological functions, we undertook systematic loss-of-function experiments on most lincRNAs defined in mouse embryonic stem cells (ESCs). We showed that knockdown of the vast majority of ESC-expressed lincRNAs has a strong effect on gene expression patterns in ESCs, of comparable magnitude to that seen for the well-known ESC regulatory proteins. We identify dozens of lincRNAs that upon loss-of-function cause an exit from the pluripotent state and dozens of additional lincRNAs that, while not essential for the maintenance of pluripotency, act to repress lineage-specific gene expression programs in ESCs. Despite their important functional roles, how lincRNAs exert their influence was unknown. We showed that many lincRNAs physically interact with the Polycomb Repressive Complex. We systematically analyzed chromatin-modifying proteins that have been shown to play critical roles in ESCs and identified 11 additional chromatin complexes that physically interact with the ESC lincRNAs. Altogether, we found that -30% of the ESC lincRNAs are associated with multiple chromatin complexes. These interactions are important for proper regulation of gene expression programs in ES cells. Our data suggests a model whereby a distinct set of lincRNAs is transcribed in a cell type and interacts with ubiquitous regulatory protein complexes to give rise to cell-type-specific RNA-protein complexes that coordinate cell-type specific gene expression programs.
by Mitchell Guttman.
Ph.D.
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Eyre-Walker, Adam C. "Studies of synonymous codon evolution in mammals". Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/14820.
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Although tremendous progress has been made in many other groups, the forces and factors which affect synonymous codon use in mammals remain something of a mystery. At least some of the differences in codon usage between mammalian genes can be summarised in terms of composition: within any one species some genes have very low G+ C contents (< 30%) and others very high G+ C content (> 90&37), with the majority lying somewhere in between. The very simplicity of this trend and the fact that this composition is correlated to that of introns and isochores suggests that the differences in synoymous codon use may be the result of variation in the pattern of mutation across the genome. This hypothesis is examined by considering the three most likely ways in which the mutation pattern might vary across the genome: (1) temporal changes in the performance of the replicative machinery; (2) variation in the efficiency of DNA repair; and (3) variation in the frequency of gene conversion across the genome. Evidence is found against all these hypotheses. Principally none of them predict the silent substitution rate to be related to G+ C content in the manner which is observed. Furthermore the lack of any discernible difference between the silent site G+ C contents of early and late replicating genes, and the very small parameter range over which DNA repair can generate large differences in synonymous codon use, support the conclusions that replication and repair, respectively, are not responsible for the codon use of mammalian genes. It is therefore suggested that selection might act upon synonymous codon use. However an analysis of codon usage within genes suggests that selection of the type commonly found in other groups, selection upon tRNA interaction, is not operative in mammals. It is tentatively suggested that selection upon mRNA secondary structure might be the responsible agent. Some of the results obtained also have implications for the maintenance of isochores. Since the G+ C contents of isochores and silent sites are correlated, the lack of any distinction with respect to composition between early and late replicating genes suggests that the differences in isochore G+ C content are not cuasd by DNA replication. However it is hypothesised that variation in the frequency of recombination can provide a very elegant explanation of the differences in isochore G+ C contents, and the relationship between gene density and isochore G+ C content.
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Milligan, Adam D. S. "The lateralisation of emotion in social mammals". Thesis, University of Stirling, 2013. http://hdl.handle.net/1893/21171.
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The study of lateralisation has taken several forms ranging from investigating morphological asymmetries to research on lateralised motor and perceptual functions with many studies successfully evidencing lateralisation in a variety of species. This study, featuring three species (olive baboons, rhesus macaques, and spotted hyaenas) investigated visual field biases with the aim of determining whether emotional valence underpins these biases whilst also considering the influence of a number of other factors such as emotional intensity, age, sex, rank, and, for the first time, oestrus cycles (olive baboons only). This study aimed to establish whether Campbell’s (1982) Right Hemisphere Hypothesis or Silberman & Weingartner’s (1986) Valence Hypothesis offered the more valid theory for the lateralisation of emotion by considering interactions across the full spectrum of emotion – a question the almost exclusive investigation of negatively affective scenarios by previous studies has been unable to answer. Furthermore, this study provided a new methodology for investigating behavioural lateralisation by suggesting that separating the visual spectrum into five fields (extreme left, mid left, centre, mid right and extreme right) allows a more accurate insight into the lateralisation of visual perception than the traditional hemifield model. Finally, a more conservative method is proposed for analysing behavioural data in future studies from this field and suggests that these methods provide a more accurate representation of the lateralisation of emotion than those previously employed. A population-level left side bias was found for the spotted hyaenas, thus providing the first evidence of significantly lateralised behaviour in a large carnivore and, for this species at least, lending some support to Campbell’s (1982) Right Hemisphere hypothesis but as population-level biases were not found for either of the other species it may be premature to suggest this support is unequivocal. Significant age effects were found in two species as adult olive baboons and spotted hyaenas were both found to express significant left side biases. Spotted hyaenas were also found to express significant left side biases for females, dominant individuals, high intensity interactions, and sexual valence interactions whilst olive baboons expressed a significant left side bias during negative valence behaviours but no significant lateral biases were found in any context for rhesus macaques. In olive baboons behaviours performed by males and those of a low intensity were found to occur more frequently in the mid and central visual fields and neutral valence behaviours were less occurrent in the extreme visual fields whilst in spotted hyaenas sexual, positive and negative valence behaviours were significantly less centralised than neutral valence behaviours. Non-oestrus adult female olive baboons were significantly more strongly lateralised than in-oestrus females, thus suggesting an influence of sex hormones upon lateralisation that may also have been apparent from the hyaena data, particularly regarding the significant lateral biases observed for females and dominant individuals. Finally, this thesis discusses a number of methodological issues that were encountered during this study and provides recommendations for future research in this field. Namely, this thesis provides an updated method for calculating laterality bias that is much more suitable for species with binocular vision and details a novel method of assessing visual field preferences by considering central and peripheral visual fields as separate entities. Furthermore, this thesis suggests that the weighted method designed and implemented for this study provides a much more accurate methodological foundation for analyses which avoids the caveats that may have affected previous research and thus provides a considerably more robust template that should be encouraged for any similar subsequent studies.
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Al, Jothery Aqeel Handil Tarish. "Lactation and oxidative stress in small mammals". Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215095.
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During peak lactation female mammals reach a limit in their maximal sustained energy intake (SusEI). The causes of such limits is disputed. In this thesis, I examined the causes of the limits on SusEI at peak lactation, and then explored the consequences of such limits for reproductive performance. Finally I tested a possible physiological mechanism that may underpin the trade-off between reproduction and somatic protection (the oxidative stress theory). To answer these questions, I studied reproductive performance and oxidative stress in two lines of mice previously selected for high and low food intake (MH and ML, respectively). I found that these mice reached a plateau in their food intake around day 13 of lactation. In support of the heat dissipation limits theory, reproductive performance in the MH mice was significantly higher than that of the ML mice. Oxidative damage is expected to be higher among lactating individuals. Moreover, lactating mice with greater reproductive performance are also predicted to experience more oxidative damage. By measuring multiple-markers of oxidative damage and protection in different tissues, I found that lactation resulted in reduced oxidative damage in both brain and serum. Additionally, it did not increase oxidative damage to proteins and DNA in liver. Moreover, multiple measures of oxidative stress in the mammary gland were not significantly different between mice with different reproductive effort. Furthermore, I found that lactating mice with greater reproductive performance (litter size and litter mass) had reduced protein damage in their livers and upregulated protection (HSP70) in their brains. These results were inconsistent with the oxidative stress theory. Finally, I employed a novel approach to assess oxidative stress differences with metabolomics analysis. I found that lactation resulted in significant differences in the metabolome. By focusing on the metabolites that are related to vi oxidative stress, I found that most of these metabolites measured in livers and brains were not affected by lactation which provides more evidence against the oxidative stress theory. My results provide support for the heat dissipation theory as a mechanism explaining the limits on reproductive performance. Moreover it provides comprehensive information against oxidative stress as a mediator of life history trade-offs.
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Moon, Derek. "Small mammals in disturbed tallgrass prairie landscapes". Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13345.
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Master of ScienceDepartment of Biology
Jack Cully, Jr.
Disturbance is defined as any discrete event that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment. Habitat use by an organism is based on its perception of where to maximize its own fitness, and can be altered in response to disturbance-induced changes in resources, substrate, or physical features modified by disturbance. Disturbance-induced changes to vegetation structure reshape a small mammal’s surrounding physical environment and/or resources, and may influence its utilization of an area. Effective wildlife and resource management is dependent on a thorough understanding of how individual species and communities utilize their surroundings and how disturbance affects a species’ response to changes in its surroundings. We investigated seasonal habitat associations of three small mammal species and for overall species diversity across a gradient of military combat-vehicle disturbance intensities at the Fort Riley Military Reservation, Kansas. Deer mouse (Peromyscus maniculatus) abundance did not vary across a categorical gradient of disturbance created by military-combat vehicles, regardless of season. Western harvest mouse (Reithrodontomys megalotis) abundance was associated with more highly disturbed areas irrespective of season. Prairie vole (Microtus ochrogaster) abundance was associated with habitat that was less disturbed in the spring but more highly disturbed in the fall. Shannon diversity of the small mammal community was higher in the more highly disturbed areas regardless of season. This research shows that small mammals respond to disturbances created by military training with combat vehicles in a species-specific manner, and indicates that there may be differences in the effects of military training versus natural or agricultural disturbances on the abundance and diversity of small mammals. This is an important consideration given that the Department of Defense manages more than 12 million ha of land in the United States, and is charged under the Sikes Act with conserving natural resources on these lands, including biological diversity. Thus, the findings of other ecological research on the effects of disturbance on small mammals may not be directly applicable to the types of disturbances that occur on military lands, which underscores the need for further research on the specific effects of military-training activities on species’ responses.
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Mota, Martorell Natàlia. "Oxidative stress homeostasis and longevity in mammals". Doctoral thesis, Universitat de Lleida, 2021. http://hdl.handle.net/10803/672775.
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Les espècies més longeves han evolucionat disminuint la producció endògena d’espècies reactives d’oxigen i proveint-se d’estructures resistents a la oxidació. Per tant, aquelles espècies que viuen més gaudeixen de mitocòndries metabòlicament més eficients i estructuralment més estables. De fet, característiques fenotípiques de la longevitat inclouen la reducció del contingut del complex I i dels aminoàcids sulfurats. Aleshores, l’activitat de determinades vies de senyalització intracel·lulars juga un paper clau regulant l’expressió de gens associats a un fenotip longeu.
En aquest context, aquesta tesi pretén determinar i) la modulació de determinades subunitats del complex I associada a la longevitat; ii) els canvis en el contingut dels aminoàcids sulfurats i els seus intermediaris metabòlics en teixits post-mitòtics i iii) plasma d’espècies més longeves; iv) la regulació del contingut dels diferents elements específics del complex 1 de mTOR en termes de longevitat; i v) l’existència un perfil metabòlic associat a humans de longevitat extrema.
Els resultats obtinguts mostren l’existència de perfils metabòlics associats a la longevitat de les espècies que, en alguns casos, són diferents a aquells perfils associats a la longevitat individual. A més, les espècies més longeves han evolucionat disminuint el contingut de determinades subunitats del complex I que podrien ésser responsables de la menor producció d’espècies reactives d’oxigen. Per altra banda, existeixen factors genètics que podrien determinar l’activitat basal de mTORC1, i que podrien, almenys en part, explicar el fenotip associat a la longevitat. Per tant, sembla que l’assoliment d’una major longevitat implica una adaptació metabòlica i estructural.Las especies más longevas han evolucionado disminuyendo la producción endógena de especies reactivas de oxígeno y proveyéndose de estructuras resistentes a la oxidación. Por lo tanto, aquellas especies que viven más disfrutan de mitocondrias metabólicamente más eficientes y estructuralmente más estables. De hecho, características fenotípicas de la longevidad incluyen la reducción del contenido del complejo I y de amino ácidos sulfurados. Por lo tanto, la activad de determinadas vías de señalización intracelular juegan un papel clave regulando la expresión de genes asociados a un fenotipo longevo. En este contexto, esta tesis pretende determinar i) la modulación de determinadas subunidades del complejo I asociada a la longevidad; ii) los cambios en el contenido de amino acido sulfurados y de sus intermediarios metabólicos en tejidos post-mitóticos y iii) plasma de especies más longevas; iv) la regulación del contenido de distintos elementos específicos del complejo 1 de mTOR en términos de longevidad; y v) la existencia de un perfil metabólico asociado a humanos de longevidad extrema. Los resultados obtenidos muestran la existencia de perfiles metabólicos asociados a la longevidad de las especies que, en algunos casos, son diferentes a aquellos perfiles asociados a la longevidad individual. Además, las especies más longevas han evolucionado disminuyendo el contenido de determinadas subunidades del complejo I que podrían ser responsables de la menor producción de especies reactivas de oxígeno. Por otra parte, existen factores genéticos que podrían determinar la actividad basal de mTOR, y que podrían, al menos en parte, explicar el fenotipo asociado a la longevidad. Por lo tanto, parece que lograr una mayor longevidad implica una adaptación metabólica y estructural.
Long-lived species have evolved by decreasing the rate of endogenous reactive oxygen species production and providing them of oxidation-resistant structures. Hence, species that live longer benefit from metabolically efficient and structurally stable mitochondria. In fact, phenotypic traits of longevity include reduced content of complex I and sulphur-containing amino acids. Then, the activity of selected intracellular signalling pathways plays a key role regulating the expression of genes associated to a longevity phenotype. In this context, this thesis aims to determine i) the modulation of specific complex I subunits associated to longevity; ii) the changes on sulphur amino acids content and its metabolic intermediates in post-mitotic tissues and ii) plasma from long-lived species; iv) the content regulation of the different mTOR complex 1 specific forming elements in terms of longevity; and v) the existence of a metabolic profile associated to human extreme longevity. The obtained results reveal the existence of metabolic profiles associated to species longevity that, in some cases, differ from those profile associated to individual longevity. Furthermore, longer lived species have evolved reducing the content of specific complex 1 subunits that might be responsible for the limited reactive oxygen species production. Otherwise, genetic factors that might determine the basal activity of mTORC1 exist, and that could, at least In part, explain the longevity associated phenotype. Thus, it seems that the achievement of an extended longevity implies a metabolic and structural adaptation.
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Omori, Taketo. "Biochemical studies of novel glycerophospholipids in mammals". Kyoto University, 2009. http://hdl.handle.net/2433/126535.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第14874号
農博第1786号
新制||農||975(附属図書館)
学位論文||H21||N4489(農学部図書室)
27296
UT51-2009-K670
京都大学大学院農学研究科応用生命科学専攻
(主査)准教授 栗原 達夫, 教授 喜多 恵子, 教授 植田 充美
学位規則第4条第1項該当
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Cooper, Natalie. "Phylogenetic approaches for studying competition in mammals". Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/4356.
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Interspecific competition is often proposed to shape mammalian evolution. Many studies use trait and distribution data on extant species, but this ignores temporal aspects of competition. Phylogeny provides a framework for integrating present-day data with clade histories. Here, I use phylogenetic comparative methods and present-day data to investigate the role of competition in the evolution of four mammalian clades: New World leaf-nosed bats (Phyllostomidae), New World monkeys (Platyrrhini), Australasian possums (Phalangeriformes), and ground squirrels (Marmotini). I ask four specific questions: (1) Do community phylogenies, and/or the traits of community members, show patterns expected under competition? (2) Is there evidence of competition in the relationship among species' trait differences, phylogenetic differences and patterns of coexistence? (3) Does the intensity of competition affect rates of morphological evolution? (4) Are the tempo and/or mode of mammalian body size evolution influenced by competition? I found evidence for competition in monkeys and squirrels, but not bats or possums. Competition did not influence rates of morphological evolution; instead body mass was the most important correlate across the groups. Across all mammals, the best-supported model of body size evolution corresponded to a scenario in which mammals experienced a relatively early burst of morphological evolution, followed by a slowdown in rate as competition for niches increased. In addition, around 60% of the variation in the tempo of body-mass evolution was explained by just a few predictors. In conclusion, I find some support for competition shaping mammalian evolution. However, there is evidence that the importance of other processes may outweigh the effects of competition in some groups. Further study and methodological improvements are required to fully understand the relative role of competition in evolution. The methods developed in this thesis provide a useful starting point for such studies.
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McDonald, Peter James. "Refuges for declining mammals in dryland Australia". Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/19905.
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Dryland Australia has a distinctive mammal fauna that has been severely impacted by novel threats since European colonisation. I aimed to understand the defining characteristics of mammal refuges in this region. In chapter 2 I used atlas data to compare the historic and contemporary distributions of dryland marsupials. The greater bilby and common brushtail possum have substantially contracted in distribution. The bilby was more likely to occur on land without cattle grazing and with low rabbit densities, while the possum has contracted to cooler areas. In chapter 3 I focused on the MacDonnell Ranges to understand the factors protecting declining mammals. Predation was supported as a major driver of extant mammal richness and vast areas of rugged terrain provide vital refuge for dryland mammals. In chapter 4 I consider the hypothesis that trophic competition between the dingo and cat creates refuge from predation for small mammals by analysing the diets of the two predators for evidence of competition. I conclude that habitat complexity underpins the refuge and that effects of dingo predation on the cat population are of secondary importance. In chapters 5-7 I focused on the critically endangered central rock-rat (CRR). My habitat suitability maps confirmed a dramatic range contraction for this species over the last 100 years and their current association with extreme ruggedness supported the hypothesis that the impact of cat predation is mediated by habitat complexity. I established the effectiveness of camera trapping for sampling the CRR and, using this sampling tool, found that CRR occupancy was positively associated with areas burnt within the past 5 years and that cats forage less frequently in areas with dense hummock grass cover. Fire management could be used as a tool for rodent conservation in this environment. In chapter 8 I synthesise my findings and provide a framework for research on declining fauna.
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Hallberg, Karen Irene. "Information in a long-distance vocal signal chorus howling in the coyote (Canis latrans) /". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1189626727.
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Celik, Melina Anouche. "Tracing the evolution of Australasian mammals: Integrating morphological, palaeontological and molecular data". Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/135716/1/Melina%20Anouche_Celik_Thesis.pdf.
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Morphological data are crucial in evolutionary analyses for merging fossils into the tree of life, calibrating dating analyses and for enhancing inference of biological patterns and processes. Morphological phylogenetics is dominated by homoplastic characters, functional and developmental correlations, and also by highly subjective definitions of characters and their states, which in turn can mislead phylogeny reconstruction. A first study assessed the implications of biases among characters in Mesozoic mammals. Then, geometric morphometrics and molecular data were combined to study the systematics of kangaroos and wallabies. Finally, new methodologies using 3D morphometrics and multivariate statistical analyses were developed for phylogenetic inference.
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Can, Ozgun Emre. "Camera Trapping Large Mammals In Yenice Forest Habitats: A Feasibility Study For Camera Trapping Large Mammals In Yenice Forests, Turkey". Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609974/index.pdf.
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Widely applicable, quantitative field methods are needed to gather wildlife data for conservation and management initiatives in Turkey. In order to evaluate the use of camera traps in forest habitats of Turkey, we conducted a 5 phase camera trap survey by using 16 passive infrared-triggered cameras with a total sampling effort of 1200 camera trap days in Yaylacik Research Forest, a 50 km2 forest patch of Yenice Forest in Karabük during January-May 2006. The camera trap survey confirmed the presence of grey wolf (Canis lupus), brown bear (Ursus arctos), wildcat (Felis silvestris), red fox (Vulpes vulpes), badger (Meles meles), pine marten (Martes martes), roe deer (Capreolus capreolus) and wild boar (Sus scrofa) in the study area. The camera trap survey also revealed the presence of jackal (Canis aureus) and brown hare (Lepus europaeus), whose presence were not known by people living and working in the area. Contrary to the local belief, neither camera trapping survey nor ground survey confirmed the presence of lynx (Lynx lynx) in Yaylacik Research Forest. The wolf was observed to be crepuscular and the wildcat showed a diurnal activity pattern. Wildcat seemed to avoid other carnivores spatially and temporally. Simulation studies suggested that camera trap surveys should last 14 days for wolf, 13 days for wildcat, 10 days for pine marten, and 11 days for roe deer, while it is advisable to conduct longer surveys, probably 15-20 days, for wild boar, red fox and brown bears. The estimated population size for wildcat was 9 (SE=2.28227) with 95% confidence interval of 9 to 25 in the study area. A minimum of 6 brown bears were present in the study area. Our study indicated that the local knowledge about the presence of wildlife should be considered by researchers, but it cannot replace scientific surveys conducted by field biologists. This study was the first attempt to assess the presence, relative abundance, activity patterns and diversity of multiple mammal species by the use of camera trapping methodology in Turkey. The results suggest that camera trap surveys have the potential for gathering wildlife data at larger scales in Turkey, where information gap on large mammals is an obstacle for effective management and conservation of mammals.
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Li, Na. "Critical role of transcription cofactor PC4 in mammals". Diss., kostenfrei, 2010. http://d-nb.info/1001408519/34.
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