984 resultados para Small Animal


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Several recent reports indicate that mobile elements are frequently found in and flanking many wild-type plant genes. To determine the extent of this association, we performed computer-based systematic searches to identify mobile elements in the genes of two "model" plants, Oryza sativa (domesticated rice) and Arabidopsis thaliana. Whereas 32 common sequences belonging to nine putative mobile element families were found in the noncoding regions of rice genes, none were found in Arabidopsis genes. Five of the nine families (Gaijin, Castaway, Ditto, Wanderer, and Explorer) are first described in this report, while the other four were described previously (Tourist, Stowaway, p-SINE1, and Amy/LTP). Sequence similarity, structural similarity, and documentation of past mobility strongly suggests that many of the rice common sequences are bona fide mobile elements. Members of four of the new rice mobile element families are similar in some respects to members of the previously identified inverted-repeat element families, Tourist and Stowaway. Together these elements are the most prevalent type of transposons found in the rice genes surveyed and form a unique collection of inverted-repeat transposons we refer to as miniature inverted-repeat transposable elements or MITEs. The sequence and structure of MITEs are clearly distinct from short or long interspersed nuclear elements (SINEs or LINEs), the most common transposable elements associated with mammalian nuclear genes. Mobile elements, therefore, are associated with both animal and plant genes, but the identity of these elements is strikingly different.

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We present a machine learning-based system for automatically computing interpretable, quantitative measures of animal behavior. Through our interactive system, users encode their intuition about behavior by annotating a small set of video frames. These manual labels are converted into classifiers that can automatically annotate behaviors in screen-scale data sets. Our general-purpose system can create a variety of accurate individual and social behavior classifiers for different organisms, including mice and adult and larval Drosophila.

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Mode of access: Internet.

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"January 11, 1909."

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The effects of short-term fasting and prolonged fasting during aestivation on the morphology of the proximal small intestine and associated organs were investigated in the green-striped burrowing frog, Cyclorana alboguttata (Anura: Hylidae). Animals were fasted for 1 week while active or for 3-9 months during aestivation. Short-duration fasting (1 week) had little effect on the morphology of the small intestine, whilst prolonged fasting during aestivation induced marked enteropathy including reductions in intestinal mass, length and diameter, longitudinal fold height and tunica muscularis thickness. Enterocyte morphology was also affected markedly by prolonged fasting: enterocyte cross-sectional area and microvillous height were reduced during aestivation, intercellular spaces were visibly reduced and the prevalence of lymphocytes amongst enterocytes was increased. Mitochondria and nuclei were also affected by 9 months of aestivation with major disruptions to mitochondrial cristae and increased clumping of nuclear material and increased infolding of the nuclear envelope. The present study demonstrates that the intestine of an aestivating frog responds to prolonged food deprivation during aestivation by reducing in size, presumably to reduce the energy expenditure of the organ.

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Most subunit vaccines require adjuvants in order to induce protective immune responses to the targeted pathogen. However, many of the potent immunogenic adjuvants display unacceptable local or systemic reactogenicity. Liposomes are spherical vesicles consisting of single (unilamellar) or multiple (multilamellar) phospholipid bi-layers. The lipid membranes are interleaved with an aqueous buffer, which can be utilised to deliver hydrophilic vaccine components, such as protein antigens or ligands for immune receptors. Liposomes, in particular cationic DDA:TDB vesicles, have been shown in animal models to induce strong humoral responses to the associated antigen without increased reactogenicity, and are currently being tested in Phase I human clinical trials. We explored several modifications of DDA:TDB liposomes--including size, antigen association and addition of TLR agonists--to assess their immunogenic capacity as vaccine adjuvants, using Ovalbumin (OVA) protein as a model protein vaccine. Following triple homologous immunisation, small unilamellar vesicles (SUVs) with no TLR agonists showed a significantly higher capacity for inducing spleen CD8 IFN? responses against OVA in comparison with the larger multilamellar vesicles (MLVs). Antigen-specific antibody reponses were also higher with SUVs. Addition of the TLR3 and TLR9 agonists significantly increased the adjuvanting capacity of MLVs and OVA-encapsulating dehydration-rehydration vesicles (DRVs), but not of SUVs. Our findings lend further support to the use of liposomes as protein vaccine adjuvants. Importantly, the ability of DDA:TDB SUVs to induce potent CD8 T cell responses without the need for adding immunostimulators would avoid the potential safety risks associated with the clinical use of TLR agonists in vaccines adjuvanted with liposomes.

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[EN] Sea turtles exhibit a strong natal homing associated with a high nesting site philopatry. Mark-recapture and genetic studies confirm these patterns suggesting differences among and within species. In the present study, we have analysed the degree of nest site fidelity of a loggerhead population nesting on the islands of Cape Verde and have evaluated the existence of intrapopulational variability in this trait. The loggerhead is the only sea turtle species that nests in Cape Verde, and 15,000–25,000 nests per season have been estimated for the whole archipelago.

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[EN] Aim: A key life-history component for many animals is the need for movement between different geographical locations at particular times. Green turtle (Chelonia mydas) hatchlings disperse from their natal location to spend an early pelagic stage in the ocean, followed by a neritic stage where small juveniles settle in coastal areas. In this study, we combined genetic and Lagrangian drifter data to investigate the connectivity between natal and foraging locations. In particular, we focus on the evidence for transatlantic transport.

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This PhD thesis focuses on current livelihoods of agro-pastoral livestock keepers, their animal nutrition, herd and rangeland management strategies. It thereby aims to contribute to sustainable rangeland management, livestock production and household income in Qinghe county of the Chinese Altay Mountain region, located in Xinjiang Uyghur Autonomous Region, PR China. In its first part the study characterizes the socio-economic situation and agricultural practices of agro-pastoralists through structured household interviews. The second part provides insights into the grazing behaviour and feed intake of small ruminants on seasonal pastures in this region, and into the quantitative and qualitative biomass offer on natural rangelands. The third part analyses the reproductive performance and annual growth of the local sheep and goat herds, and, by modelling improved feeding and culling strategies, tests herd management options that potentially improve the monetary output per female herd animal without increasing the pressure onto natural rangelands. Taken together, the results of the study suggest that, despite an increase and intensification of cropping and vegetable gardening in the region of Qinghe, livestock rearing is still the major livelihood strategy both in terms of prevalence and relative importance. However, livestock keeping is challenged by low biomass production on rangelands, due to the combined impact of high climate variability and highly localized grazing pressure on the seasonal pastures. Though government regulations try to tackle the latter aspect, their implementation is sometimes difficult. Alternatives to strict regulation of grazing periods and animal numbers on seasonal pastures are, in the case of goats, more rigorous culling strategies and, in the case of sheep and goats, strategic supplementation of the animals in the winter and spring season. However, for the latter strategy to become economically viable, an improvement of live animal and meat marketing options and an investment in local meat processing facilities that add value to the carcasses is needed. As the regional cities grow rapidly, the potential market to absorb diverse and good quality meat products is there, along with the road network connecting Qinghe county to the regional capital. Such governmental measures will not only create new job opportunities in the region but also benefit the cash income of pastoralists in this westernmost region of China.

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[EN] Green turtle hatchlings disperse away from their natal location to spend an early pelagic stage in the ocean, followed by a neritic stage where small juveniles settle in coastal areas. Here, we combined genetic and Lagrangian drifter data to investigate the connectivity between natal and foraging locations; particularly focussing on the evidence for transatlantic transport. Our results supported the general hypothesis that turtles tend to select foraging areas ‘closest-to-home’.

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Campylobacter is a leading cause of foodborne bacterial gastroenteritis worldwide and infections can be fatal. The emergence of antibiotic-resistant Campylobacter spp. necessitates the development of new antimicrobials. We identified novel anti-Campylobacter small molecule inhibitors using a high throughput growth inhibition assay. To expedite screening, we made use of a “bioactive” library of 4,182 compounds that we have previously shown to be active against diverse microbes. Screening for growth inhibition of Campylobacter jejuni, identified 781 compounds that were either bactericidal or bacteriostatic at a concentration of 200 µM. Seventy nine of the bactericidal compounds were prioritized for secondary screening based on their physico-chemical properties. Based on the minimum inhibitory concentration against a diverse range of C. jejuni and a lack of effect on gut microbes, we selected 12 compounds. No resistance was observed to any of these 12 lead compounds when C. jejuni was cultured with lethal or sub-lethal concentrations suggesting that C. jejuni is less likely to develop resistance to these compounds. Top 12 compounds also possessed low cytotoxicity to human intestinal epithelial cells (Caco-2 cells) and no hemolytic activity against sheep red blood cells. Next, these 12 compounds were evaluated for ability to clear C. jejuni in vitro. A total of 10 compounds had an anti-C. jejuni effect in Caco-2 cells with some effective even at 25 µM concentrations. These novel 12 compounds belong to five established antimicrobial chemical classes; piperazines, aryl amines, piperidines, sulfonamide and pyridazinone. Exploitation of analogues of these chemical classes may provide Campylobacter specific drugs that can be applied in both human and animal medicine.