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991.
Scott RA Moran C Wilson RH Onywera V Boit MK Goodwin WH Gohlke P Payne J Montgomery H Pitsiladis YP 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2005,141(2):169-175
East African runners are continually successful in international distance running. The extent to which genetic factors influence this phenomenon is unknown. The insertion (I) rather than deletion (D) of a 287 bp fragment in the human angiotensin converting enzyme (ACE) gene is associated with lower circulating and tissue ACE activity and with endurance performance amongst Caucasians. To assess the association between ACE gene variation and elite endurance athlete status in an African population successful in distance running, DNA samples were obtained from 221 national Kenyan athletes (N), 70 international Kenyan athletes (I), and 85 members of the general Kenyan population (C). Blood samples were obtained from C and assayed for circulating ACE activity. ACE I/D (rs????--from NCBI SNPdb first time poly mentioned) genotype was determined, as was genotype at A22982GD (rs????--from NCBI SNPdb first time poly mentioned) which has been shown to associate more closely with ACE levels in African subjects than the I/D polymorphism. ACE I/D and A22982G genotypes explained 13 and 24% of variation in circulating ACE activity levels (P = 0.034 and <0.001 respectively). I/D genotype was not associated with elite endurance athlete status (df = 4, chi(2) = 4.1, P=0.39). In addition, genotype at 22982 was not associated with elite endurance athlete status (df = 4, chi(2) = 5.7, P = 0.23). Nor was the A allele at 22982, which is associated with lower ACE activity, more prevalent in N (0.52) or I (0.41) relative to C (0.53). We conclude that ACE I/D and A22982G polymorphisms are not strongly associated with elite endurance athlete status amongst Kenyans. 相似文献
992.
Gueguen N Lefaucheur L Fillaut M Vincent A Herpin P 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2005,140(2):287-297
Skeletal muscle exhibits considerable variation in mitochondrial content among fiber types, but it is less clear whether mitochondria from different fiber types also present specific functional and regulatory properties. The present experiment was undertaken on ten 170-day-old pigs to compare functional properties and control of respiration by adenine nucleotides in mitochondria isolated from predominantly slow-twitch (Rhomboideus (RM)) and fast-twitch (Longissimus (LM)) muscles. Mitochondrial ATP synthesis, respiratory control ratio (RCR) and ADP-stimulated respiration with either complex I or II substrates were significantly higher (25-30%, P<0.05) in RM than in LM mitochondria, whereas no difference was observed for basal respiration. Based on mitochondrial enzyme activities (cytochrome c oxidase [COX], F0F1-ATPase, mitochondrial creatine kinase [mi-CK]), the higher ADP-stimulated respiration rate of RM mitochondria appeared mainly related to a higher maximal oxidative capacity, without any difference in the maximal phosphorylation potential. Mitochondrial K(m) for ADP was similar in RM (4.4+/-0.9 microM) and LM (5.9+/-1.2 microM) muscles (P>0.05) but the inhibitory effect of ATP was more marked in LM (P<0.01). These findings demonstrate that the regulation of mitochondrial respiration by ATP differs according to muscle contractile type and that absolute muscle oxidative capacity not only relies on mitochondrial density but also on mitochondrial functioning per se. 相似文献
993.
Mitchell C Mallet V Guidotti JE Mignon A Couton D Kahn A Gilgenkrantz H 《Journal de la Société de Biologie》2005,199(3):243-246
In the liver, the importance of apoptosis is not only evident during development and homeostasis of the biliary tree but plays also a prominent role in liver pathogenesis. Ligand binding to cell surface death receptors such as Fas activates the extrinsic pathway. This pathway predominates in autoimmune liver diseases, viral hepatitis, liver allograft rejection. Hepatocyte apoptosis is also significantly increased in patients with alcoholic hepatitis and nonalcoholic steatohepatitis and correlates with disease severity and hepatic fibrosis. We have used this specific susceptibility of the liver to apoptosis to develop two different approaches: 1) a cell therapy strategy based on a survival advantage to an apoptotic stimulus conferred to transplanted hepatocytes and 2) a new model of hepatocyte conditional ablation based on a controlled activation of the cell death program. 相似文献
994.
995.
Zhang Z Ren Q Yang H Conrad MN Guacci V Kateneva A Dresser ME 《Molecular microbiology》2005,56(3):670-680
Budding yeast PDS5 is an essential gene in mitosis and is required for chromosome condensation and sister chromatid cohesion. Here we report that PDS also is required in meiosis. Pds5p localizes on chromosomes at all stages during meiotic cycle, except anaphase I. PDS5 plays an important role at first meiotic prophase. Failure in function of PDS5 causes premature separation of chromosomes. The loading of Pds5p onto chromosome requires the function of REC8, but the association of Rec8p with chromosome is independent of PDS5. Mutant analysis and live cell imaging indicate that PDS5 play a role in meiosis II as well. 相似文献
996.
Although gammalinolenic acid (GLA) and eicosapentaenoic acid (EPA) have independently been reported to suppress growth of cancer cells, their relative potencies are unknown. To determine the possible attenuating efficacies of dietary GLA or EPA on prostate carcinogenesis, we hereby report the in vitro effects of GLA, EPA and their 15-lipoxygenase (15-LOX) metabolites: 15(S)-HETrE and 15(S)-HEPE, respectively, on growth and arachidonic acid (AA) metabolism in human androgen-dependent (LNCaP) and androgen-independent (PC-3) prostatic cancer cells in culture. Specifically, both cells were preincubated respectively with the above PUFAs. Growth was determined by [3H]thymidine uptake and AA metabolism by HPLC analysis of the extracted metabolites. Our data revealed increased biosynthesis of prostaglandin E2 (PGE2) and 5-hydroxyeicosatetraenoic acid (5(S)-HETE) by both cells. Preincubation of the cells with 15(S)-HETrE or 15(S)-HEPE more markedly inhibited cellular growth and AA metabolism when compared to precursor PUFAs. Notably, 15(S)-HETrE exerted the greatest inhibitory effects. These findings therefore imply that dietary GLA rather than EPA should better attenuate prostate carcinogenesis via its in vivo generation of 15(S)-HETrE, thus warranting exploration. 相似文献
997.
Small reducing and linear oligo-beta-(1,3)-glucans, which are able to act as phytoallexin elicitors or as immunostimulating agents in anticancer therapy, were synthesized according to an iterative strategy that involved a unique key monosaccharidic donor. To avoid anomeric mixtures, the reducing entity of the target oligomers was first locked with benzyl alcohol and further selective deprotection of the 3-OH with DDQ afforded the desired building block as an acceptor. The latter was then used in a second cycle of glycosylation/deprotection to afford the desired disaccharide, and successive reiterations of this process provided the desired oligomers. Unusual conformational behaviors were observed by standard NMR sequences and supported by NOESY studies. Finally, removal of protecting groups afforded free tri-, tetra-, and pentaglucosides in good overall yields. Two oligosaccharides representing linear laminaritetraose and laminaripentaose were compared to the recently described beta-(1,3)-glucan phycarine. Following an intraperitoneal injection, the influx of monocytes and granulocytes into the blood and macrophages into the peritoneal cavity was comparable to that caused by phycarine. Similarly, both oligosaccharides stimulated phagocytic activity of granulocytes and macrophages. Using ELISA, we also demonstrated a significant stimulation of secretion of IL-1beta. Together these results suggest that the synthetic oligosaccharides have similar stimulatory effects as natural beta-(1,3)-glucans. 相似文献
998.
Manuel B.?MoralesEmail author Vincent?Bretagnolle Beatriz?Arroyo 《Biodiversity and Conservation》2005,14(13):3135-3150
Stochastic computer simulations are used to evaluate the sensitivity of Little bustard population parameters, estimating the
survival probabilities of the seven endangered Little bustard populations of central-western France for which conservation
actions are currentlybeing or have been implemented. Different scenarios of parameter compensation for those nuclei to establish
parameter levels assuring population viability are discussed. Adult survival, productivity per female, initial population
size and carrying capacity were the most sensitive parameters in a hypothetical, isolated population. Juvenile survival also
affected population survival, although its sensitivity was lower. Sex ratio did not have a linear effect on population survival,
but probability of extinction increased for extreme values. Productivity per female and initial population size, varied strongly
among the populations studied, determining their average time of extinction and growth rate. When a metapopulation scenario
was simulated, the survival probabilities of each population and the metapopulations stayed close to 1.0 if no mortality was
associated to migration. When mortality during migration was included in the simulations, the metapopulation's probability
of survival significantly decreased under 90%. This approach may help managers to correctly address conservation measures
and design effective strategies, which should be directed mainly to improve productivity, enhance female survival, and minimise
mortality during migration (e.g. promoting insect-rich nesting substrates, avoiding female killing and nest destruction at
harvesting, reducing the risk of collision with powerlines, or controlling poaching). 相似文献
999.
Zhao C Sham HL Sun M Stoll VS Stewart KD Lin S Mo H Vasavanonda S Saldivar A Park C McDonald EJ Marsh KC Klein LL Kempf DJ Norbeck DW 《Bioorganic & medicinal chemistry letters》2005,15(24):7604-5503
As part of our efforts to identify potent HIV-1 protease inhibitors that are active against resistant viral strains, structural modification of the azacyclic urea (I) was undertaken by incorporating acyl groups as P1′ ligands. The extensive SAR study has yielded a series of N-acyl azacyclic ureas (II), which are highly potent against both wild-type and multiple PI-resistant viral strains. 相似文献
1000.
Zask A Kaplan J Du X MacEwan G Sandanayaka V Eudy N Levin J Jin G Xu J Cummons T Barone D Ayral-Kaloustian S Skotnicki J 《Bioorganic & medicinal chemistry letters》2005,15(6):1641-1645
Potent and selective TACE and MMP inhibitors utilizing the diazepine and thiazepine ring systems were synthesized and evaluated for biological activity in in vitro and in vivo models of TNF-alpha release. Oral activity in the mouse LPS model of TNF-alpha release was seen. Efficacy in the mouse collagen induced arthritis model was achieved with diazepine 20. 相似文献