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排序方式: 共有190条查询结果,搜索用时 328 毫秒
91.
92.
Sreeram V Ramagopalan William Valdar David A Dyment Gabriele C DeLuca Sarah-Michelle Orton Irene M Yee Maria Criscuoli George C Ebers A Dessa Sadovnick for the Canadian Collaborative Study Group 《BMC neurology》2008,8(1):30
Background
Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. A clear parent of origin effect has been shown in several populations, perhaps resulting from factors operating during gestation. Preterm birth (birth at less than 37 weeks gestational age) has been shown to result in long-term health problems, including impaired neurological development. Here, in a population-based cohort, we investigate whether preterm birth increases the risk to subsequently develop MS.Methods
We identified 6585 MS index cases and 2509 spousal controls with preterm birth information from the Canadian Collaborative Project on Genetic Susceptibility to MS. Rates of individuals born preterm were compared for index cases and controls.Results
There were no significant differences between cases and controls with respect to preterm births. 370 (5.6%) MS index cases and 130 (5.2%) spousal controls were born preterm, p = 0.41.Conclusion
Preterm birth does not appear to contribute to MS aetiology. Other factors involved in foetal and early development need to be explored to elucidate the mechanism of the increased risk conferred by the apparent maternal effect.93.
94.
Frank O. Aylward Lily Khadempour Daniel M. Tremmel Bradon R. McDonald Carrie D. Nicora Si Wu Ronald J. Moore Daniel J. Orton Matthew E. Monroe Paul D. Piehowski Samuel O. Purvine Richard D. Smith Mary S. Lipton Kristin E. Burnum-Johnson Cameron R. Currie 《PloS one》2015,10(8)
Leaf-cutter ants are prolific and conspicuous constituents of Neotropical ecosystems that derive energy from specialized fungus gardens they cultivate using prodigious amounts of foliar biomass. The basidiomycetous cultivar of the ants, Leucoagaricus gongylophorus, produces specialized hyphal swellings called gongylidia that serve as the primary food source of ant colonies. Gongylidia also contain plant biomass-degrading enzymes that become concentrated in ant digestive tracts and are deposited within fecal droplets onto fresh foliar material as ants incorporate it into the fungus garden. Although the enzymes concentrated by L. gongylophorus within gongylidia are thought to be critical to the initial degradation of plant biomass, only a few enzymes present in these hyphal swellings have been identified. Here we use proteomic methods to identify proteins present in the gongylidia of three Atta cephalotes colonies. Our results demonstrate that a diverse but consistent set of enzymes is present in gongylidia, including numerous plant biomass-degrading enzymes likely involved in the degradation of polysaccharides, plant toxins, and proteins. Overall, gongylidia contained over three quarters of all biomass-degrading enzymes identified in the L. gongylophorus genome, demonstrating that the majority of the enzymes produced by this fungus for biomass breakdown are ingested by the ants. We also identify a set of 40 of these enzymes enriched in gongylidia compared to whole fungus garden samples, suggesting that certain enzymes may be particularly important in the initial degradation of foliar material. Our work sheds light on the complex interplay between leaf-cutter ants and their fungal symbiont that allows for the host insects to occupy an herbivorous niche by indirectly deriving energy from plant biomass. 相似文献
95.
Schofield DJ Pope AR Clementel V Buckell J Chapple SDj Clarke KF Conquer JS Crofts AM Crowther SR Dyson MR Flack G Griffin GJ Hooks Y Howat WJ Kolb-Kokocinski A Kunze S Martin CD Maslen GL Mitchell JN O'Sullivan M Perera RL Roake W Shadbolt SP Vincent KJ Warford A Wilson WE Xie J Young JL McCafferty J 《Genome biology》2007,8(11):R254-18
We have created a high quality phage display library containing over 1010 human antibodies and describe its use in the generation of antibodies on an unprecedented scale. We have selected, screened and sequenced over 38,000 recombinant antibodies to 292 antigens, yielding over 7,200 unique clones. 4,400 antibodies were characterized by specificity testing and detailed sequence analysis and the data/clones are available online. Sensitive detection was demonstrated in a bead based flow cytometry assay. Furthermore, positive staining by immunohistochemistry on tissue microarrays was found for 37% (143/381) of antibodies. Thus, we have demonstrated the potential of and illuminated the issues associated with genome-wide monoclonal antibody generation. 相似文献
96.
Background
In a number of species males damage females during copulation, but the reasons for this remain unclear. It may be that males are trying to manipulate female mating behaviour or their life histories. Alternatively, damage may be a side-effect of male-male competition. In the black scavenger or dung fly Sepsis cynipsea (Diptera: Sepsidae) mating reduces female survival, apparently because males wound females during copulation. However, this damage does not seem to relate to attempted manipulation of female reproduction by males. Here we tested the hypothesis that harming females during mating is an incidental by-product of characters favoured during pre-copulatory male-male competition. We assessed whether males and their sons vary genetically in their ability to obtain matings and harm females, and whether more successful males were also more damaging. We did this by ranking males' mating success in paired competitions across several females whose longevity under starvation was subsequently measured. 相似文献97.
98.
Synopsis The histochemical method of Adamset al. (1966) for demonstrating triglycerides in tissue sections was applied to kidneys exhibiting a wide variety of disease states. It became apparent, as would be expected, that the existing method demonstrates not only triglycerides but also free fatty acids in the same section. Even though the presence of free fatty acids could be detected in the control sections, their existence made it impossible to identify triglycerides with certainty.A modification is described which employs a potassium hydroxide-dioxan mixture to saponify and extract selectively free fatty acids from tissue sections. Fatty acids in free form can be demonstrated separately, in parallel sections, from those esterified as triglyceride. This modified technique was applied to frozen sections of formalin-fixed human and rat tissues, revealing distinct and highly characteristic distribution patterns for these two forms of fatty acid. 相似文献
99.
Elution of exocellular enzymes from Saccharomyces fragilis and Saccharomyces cerevisiae 总被引:8,自引:2,他引:6
Weimberg, Ralph (Northern Regional Research Laboratory, Peoria, Ill.), and William L. Orton. Elution of exocellular enzymes from Saccharomyces fragilis and Saccharomyces cerevisiae. J. Bacteriol. 91:1-13. 1966.-Invertase and acid phosphatase are repressible exocellular enzymes in Saccharomyces fragilis and S. cerevisiae. The conditions for eluting these enzymes from both organisms were compared. Either KCl or beta-mercaptoethanol eluted the enzymes from S. fragilis, and the amounts eluted varied quantitatively according to the physiological age of the organism. In addition to eluting enzymatic activity from the cells, these reagents also caused a large increase in the amount of activity that remained associated with the cells of S. fragilis. Invertase and acid phosphatase were not removed from cells of S. cerevisiae by KCl or beta-mercaptoethanol. These enzymes were separated from S. cerevisiae cells only when there was some degree of cell-wall digestion by snail gut fluid. 相似文献
100.
Orton ER 《Genetics》1966,53(1):17-25