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991.
Villamil Giraldo AM Castello PR González Flecha FL Moeller JV Delfino JM Rossi JP 《FEBS letters》2006,580(2):607-612
Here we undertook a comparative study of the composition of the lipid annulus of three ATPases pertaining to the P-type family: plasma membrane calcium pump (PMCA), sarcoplasmic reticulum calcium pump (SERCA) and Na,K-ATPase. The photoactivatable phosphatidylcholine analogue [(125)I]TID-PC/16 was incorporated into mixtures of dimyristoyl phosphatidylcholine (DMPC) and each enzyme with the aid of the nonionic detergent C(12)E(10). After photolysis, the extent of the labeling reaction was assessed to determine the lipid:protein stoichiometry: 17 for PMCA, 18 for SERCA, 24 for the Na,K-ATPase (alpha-subunit) and 5.6 mol PC/mol protein for the Na,K-ATPase (beta-subunit). 相似文献
992.
During the “Workshop on Arctic tardigrades” at the Danish Arctic Station (Qeqertarsuaq, Disko Island, Greenland) an undescribed
species of Dactylobiotus was found in freshwater sediments of the Isunngua spring. We have the honour and pleasure to describe this new taxon that
we dedicate to all participants of that symposium, naming the species Dactylobiotus octavi sp. n. The animals appear similar to Dactylobiotus dispar and Dactylobiotus haplonyx with the presence of a very short secondary branch in the claws of the first three pairs of legs, but they differ from these
species in the size of claw and buccal tube width. This new species also has peculiar ornamented eggs. The eggshell consists
of bowl-like processes, each one surrounded by a band of fine pores. A morphological parsimony analysis to identify phylogenetic
relationships among D. octavi sp. n. and the other Dactylobiotus species was performed, obtaining inconclusive results. The discovery of this new species increases an unsolved paradox in
tardigrade systematics related to the presence of closely related species which share a very similar morphology of the animals
but clearly differ in their egg morphology, while, conversely, there are species belonging to different evolutionary lines
that have similar eggs, but very different adult morphology. The finding of D. octavi sp. n. increases the already high number of species found in Disko Island and once again underlines the importance of tardigrades
in the biodiversity of the Arctic area. 相似文献
993.
994.
Østergård T Andersen JL Nyholm B Lund S Nair KS Saltin B Schmitz O 《American journal of physiology. Endocrinology and metabolism》2006,290(5):E998-1005
First-degree relatives of type 2 diabetic patients (offspring) are often characterized by insulin resistance and reduced physical fitness (VO2 max). We determined the response of healthy first-degree relatives to a standardized 10-wk exercise program compared with an age-, sex-, and body mass index-matched control group. Improvements in VO2 max (14.1 +/- 11.3 and 16.1 +/- 14.2%; both P < 0.001) and insulin sensitivity (0.6 +/- 1.4 and 1.0 +/- 2.1 mg x kg(-1) x min(-1); both P < 0.05) were comparable in offspring and control subjects. However, VO2 max and insulin sensitivity in offspring were not related at baseline as in the controls (r = 0.009, P = 0.96 vs. r = 0.67, P = 0.002). Likewise, in offspring, exercise-induced changes in VO2 max did not correlate with changes in insulin sensitivity as opposed to controls (r = 0.06, P = 0.76 vs. r = 0.57, P = 0.01). Skeletal muscle oxidative capacity tended to be lower in offspring at baseline but improved equally in both offspring and controls in response to exercise training (delta citrate synthase enzyme activity 26 vs. 20%, and delta cyclooxygenase enzyme activity 25 vs. 23%. Skeletal muscle fiber morphology and capillary density were comparable between groups at baseline and did not change significantly with exercise training. In conclusion, this study shows that first-degree relatives of type 2 diabetic patients respond normally to endurance exercise in terms of changes in VO2 max and insulin sensitivity. However, the lack of a correlation between the VO2 max and insulin sensitivity in the first-degree relatives of type 2 diabetic patients indicates that skeletal muscle adaptations are dissociated from the improvement in VO2 max. This could indicate that, in first-degree relatives, improvement of insulin sensitivity is dissociated from muscle mitochondrial functions. 相似文献
995.
Bethany J. Hoye Vincent J. Munster Hiroshi Nishiura Ron A. M. Fouchier Jesper Madsen Marcel Klaassen 《Oikos》2011,120(5):748-755
Migratory animals may play an important role in connecting disparate ecosystems, including the introduction of various pathogens. The incidence of these pathogens may vary over time and space, such that events along the entire migratory flyway are likely to be important in the interaction between pathogens and their migratory hosts. On this premise, the annual cycle of a naturally occurring host–pathogen system was reconstructed by examining infection with and antibodies to avian influenza virus along the flyway of a long‐distance Arctic migrant, the Svalbard‐breeding pink‐footed goose Anser brachyrhynchus. A highly‐localized transmission period was identified in winter, in contrast to the north–south decline expected from dabbling ducks, indicating the dynamics of infection may differ among host species. In spring, 63% (95% CI: 57.1, 68.9) of adults had detectable antibodies to the nucleoprotein of avian influenza virus, compared to just 15% (95% CI: 8.7, 23.4) of juveniles, suggesting inter‐annual antibody maintenance. Nevertheless, adult seroprevalence declined by approximately 30% from spring to late summer, indicating significant seroreversion in the population. Integrating these findings in an epidemiological model, detectable antibodies to nucleoprotein were estimated to persist for just 343 days (95% CI: 221, 607); considerably shorter than for other wildlife diseases in long‐lived bird species. The investigation of wildlife diseases in migratory populations is an inherently complex task, yet, by integrating disease incidence and seroprevalence along a migratory flyway, our findings suggest that the ecological interactions and life history of the host, as well as the life‐history of the pathogen, can influence the dynamics of infection and host immune response. 相似文献
996.
Acclimation responses to short‐term temperature treatments during early life stages causes long lasting changes in spontaneous activity of adult Drosophila melanogaster
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Heidi J. MacLean Torsten N. Kristensen Johannes Overgaard Jesper G. Sørensen Simon Bahrndorff 《Physiological Entomology》2017,42(4):404-411
Ecotherms adjust their physiology to environmental temperatures. Long‐term exposures to heat or cold typically induce acclimation responses that generate directional, but reversible shifts in thermal tolerance and performance. However, less is known about how short exposure in different life stages will affect the adult phenotype. In the present study, we compared the effects of long‐term temperature exposure to 15, 19 and 31 °C with that of brief (16 h) exposure periods at the same temperatures in Drosophila melanogaster eggs, larvae, pupae, or adults, respectively. The acclimation responses are evaluated using activity measurements at 11, 15, 19, 27, 31 and 33 °C and by measuring upper and lower thermal limits (CTmax and CTmin) in 5‐day‐old adult males. As expected, long‐term cold exposure reduces relative CTmin, whereas long‐term heat exposure increases relative CTmax. By contrast, we find little effect on thermal limits when using short‐term exposures at different life stages. Long‐term exposures to 31 and 15 °C both suppressed activity relative to the 19 °C control, suggesting that development at high and low temperatures may lead to reduced activity later in life. Short‐term cold exposure early in development reduces activity in the adult stage, whereas the effects of short‐term heat exposure on behaviour are dependent on life stage and test temperature. Together, our results highlight how the thermal sensitivity of the trait measured determines the ability to detect acclimation responses. 相似文献
997.
998.
Andreas H. Ehrensberger Don-Marc Franchini Philip East Roger George Nik Matthews Sarah L. Maslen Jesper Q. Svejstrup 《PloS one》2015,10(8)
A protocol is presented for the isolation of native mammalian chromatin as fibers of 25–250 nucleosomes under conditions that preserve the natural epigenetic signature. The material is composed almost exclusively of histones and DNA and conforms to the structure expected by electron microscopy. All sequences probed for were retained, indicating that the material is representative of the majority of the genome. DNA methylation marks and histone marks resembled the patterns observed in vivo. Importantly, nucleosome positions also remained largely unchanged, except on CpG islands, where nucleosomes were found to be unstable. The technical challenges of reconstituting biochemical reactions with native mammalian chromatin are discussed. 相似文献
999.
John H. Lagergren John T. Nardini Ruth E. Baker Matthew J. Simpson Kevin B. Flores 《PLoS computational biology》2020,16(12)
Biologically-informed neural networks (BINNs), an extension of physics-informed neural networks [1], are introduced and used to discover the underlying dynamics of biological systems from sparse experimental data. In the present work, BINNs are trained in a supervised learning framework to approximate in vitro cell biology assay experiments while respecting a generalized form of the governing reaction-diffusion partial differential equation (PDE). By allowing the diffusion and reaction terms to be multilayer perceptrons (MLPs), the nonlinear forms of these terms can be learned while simultaneously converging to the solution of the governing PDE. Further, the trained MLPs are used to guide the selection of biologically interpretable mechanistic forms of the PDE terms which provides new insights into the biological and physical mechanisms that govern the dynamics of the observed system. The method is evaluated on sparse real-world data from wound healing assays with varying initial cell densities [2]. 相似文献
1000.
The Val985Met Insulin-Receptor Variant in the Danish Caucasian Population: Lack of Associations with Non-Insulin-Dependent Diabetes Mellitus or Insulin Resistance
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