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991.
An ultrastructural study of the manchette was carried out on 21 species belonging to the culicid genera Aedes, Anopheles, Culex and Toxorhynchites . Each genus has a characteristic morphological type of manchette. Toxorhynchites seems to have the type found in many other Diptera, while the other genera have unusual types. 相似文献
992.
993.
Endurance training affects myosin heavy chain phenotype in regenerating fast-twitch muscle 总被引:2,自引:0,他引:2
Bigard Xavier A.; Janmot Chantal; Merino Daniele; Lienhard Francoise; Guezennec Yannick C.; D'Albis Anne 《Journal of applied physiology》1996,81(6):2658-2665
Bigard, Xavier A., Chantal Janmot, Danièle Merino,Françoise Lienhard, Yannick C. Guezennec, and Anne D'Albis.Endurance training affects myosin heavy chain phenotype inregenerating fast-twitch muscle. J. Appl.Physiol. 81(6): 2658-2665, 1996.The aim of thisstudy was to analyze the effects of treadmill training (2 h/day, 5 days/wk, 30 m/min, 7% grade for 5 wk) on the expression of myosinheavy chain (MHC) isoforms during and after regeneration of afast-twitch white muscle [extensor digitorum longus (EDL)]. Male Wistar rats were randomly assigned to a sedentary(n = 10) or an endurance-trained (ET;n = 10) group. EDL muscle degeneration and regeneration were induced by two subcutaneous injections of a snaketoxin. Five days after induction of muscle injury, animals were trainedover a 5-wk period. It was verified that ~40 days after venomtreatment, central nuclei were present in the treated EDL muscles fromsedentary and ET rats. The changes in the expression of MHCs in EDLmuscles were detected by using a combination of biochemical andimmunocytochemical approaches. Compared with contralateral nondegenerated muscles, relative concentrations of types I, IIa, andIIx MHC isoforms in ET rats were greater in regenerated EDL muscles(146%, P < 0.05; 76%,P < 0.01; 87%,P < 0.01, respectively). Their elevation corresponded to a decreasein the relative concentration of type IIb MHC (36%,P < 0.01). Although type I accountedfor only 3.2% of total myosin in regenerated muscles from the ETgroup, the cytochemical analysis showed that the proportion of positive staining with the slow MHC antibody was markedly greater in regenerated muscles than in contralateral ones. Collectively, these results demonstrate that the regenerated EDL muscle is sensitive to endurance training and suggest that the training-induced shift in MHC isoforms observed in these muscles resulted from an additive effect of regeneration and repeated exercise. 相似文献
994.
A. M. A. Nascimento H. R. T. Souza M. S. Xavier J. E. Thiemann L. Vilela M. Mares-Guia 《Biotechnology Techniques》1996,10(10):737-742
Summary A proinsulin analog constructed by site-directed mutagenesis was expressed as a fusion protein that formed inclusion bodies inside the cells. It was purified from the isolated inclusion bodies and proinsulin was obtained by trifluoro-acetic acid, dimethyl sulfoxide and hydrochloric acid cleavage. The released proinsulin analog was confirmed by its molecular weight as determined by SDS-PAGE. 相似文献
995.
A proposed architecture for the central domain of the bacterial enhancer-binding proteins based on secondary structure prediction and fold recognition 下载免费PDF全文
Joel Osuna Xavier Soberon Enrique Morett 《Protein science : a publication of the Protein Society》1997,6(3):543-555
The expression of genes transcribed by the RNA polymerase with the alternative sigma factor <r54 (Ecr54) is absolutely dependent on activator proteins that bind to enhancer-like sites, located far upstream from the promoter. These unique prokaryotic proteins, known as enhancer-binding proteins (EBP), mediate open promoter complex formation in a reaction dependent on NTP hydrolysis. The best characterized proteins of this family of regulators are NtrC and Nif A, which activate genes required for ammonia assimilation and nitrogen fixation, respectively. In a recent IRBM course (“Frontiers of protein structure prediction,” IRBM, Pomezia, Italy, 1995; see web site http://www.mrc-cpe.cam.uk/ irbm-course95/), one of us (J.O.) participated in the elaboration of the proposal that the Central domain of the EBPs might adopt the classical mononucleotide-binding fold. This suggestion was based on the results of a new protein fold recognition algorithm (Map) and in the mapping of correlated mutations calculated for the sequence family on the same mononucleotide-binding fold topology. In this work, we present new data that support the previous conclusion. The results from a number of different secondary structure prediction programs suggest that the Central domain could adopt an alfi topology. The fold recognition programs ProFIT 0.9, 3D PROFILE combined with secondary structure prediction, and 123D suggest a mononucleotide-binding fold topology for the Central domain amino acid sequence. Finally, and most importantly, three of five reported residue alterations that impair the Central domain ATPase activity of the Eo-54 activators are mapped to polypeptide regions that might be playing equivalent roles as those involved in nucleotide-binding in the mononucleotide-binding proteins. Furthermore, the known residue substitutions that alter the function of the Ecr54 activators, leaving intact the Central domain ATPase activity, are mapped on a region proposed to play an equivalent role as the effector region of the GTPase superfamily. 相似文献
996.
997.
Sochung Chung Mi-Yeon Song Hyun-Dae Shin Deog-Yoon Kim Qing He Stan Heshka Jack Wang John Thornton Blandine Laferrère F Xavier Pi-Sunyer Dympna Gallagher 《Journal of applied physiology》2005,99(1):103-107
The aim of the study was to investigate in premenopausal women whether the relationship between percentage body fat (PBF) and body mass index (BMI; in kg/m2) differs between Korean Asians (Ko-As) living in Seoul, South Korea, and Caucasians (Ca) living in New York City. Healthy premenopausal women (50 Ko-As; 38 Ca), ages 22-50 yr, were studied. Weight, height, and PBF by dual-energy X-ray absorptiometry were measured. Total body dual-energy X-ray absorptiometry data were collected using GE-Lunar systems (Prodigy-Korea and DPXL-New York), and all scan analyses were performed by one technician in New York. Similar soft tissue phantoms were used for daily instrument calibrations at both sites. The relationship between PBF and BMI was assessed by multiple regression analysis with race, age, reciprocal of BMI (1/BMI), and a race-by-age interaction as the final independent variables. Race (P = 0.003) and 1/BMI (P < 0.001) were significantly related to PBF in this model. A significant race-by-age interaction (P = 0.039) indicated that the slope of the lines for PBF vs. age differed between Ko-As and Ca. This study demonstrates in a Ko-As sample that the BMI-fat relationship differs significantly from that in a comparable group of Caucasian women. Investigators who use BMI as an index of fatness should be aware of the well documented differences in the relationship of BMI and fatness across race/ethnic groups. 相似文献
998.
Therapeutic Approaches in Mitochondrial Dysfunction,Proteolysis, and Structural Alterations of Diaphragm and Gastrocnemius in Rats With Chronic Heart Failure 下载免费PDF全文
999.
Genetic markers validate using the natural phenotypic characteristics of shed feathers to identify individual northern goshawks Accipiter gentilis 下载免费PDF全文
Sarah R. Hoy Rachel E. Ball Xavier Lambin D. Philip Whitfield Michael Marquiss 《Journal of avian biology》2016,47(3):443-447
The recognition of individual animals is essential for many types of ecological research, as it enables estimates of demographic parameters such as population size, survival and reproductive rates. A popular method of visually identifying individuals uses natural variations in spot, stripe or scar markings. Although several studies have assessed the accuracy of these methods in mammals, crustaceans and fish, there have been few attempts to determine whether phenotypic characteristics are accurate when used for birds. Furthermore, even less is known about whether shed or moulted body parts can be reliably used to visually identify individuals. Here we assessed the accuracy of using phenotypic characteristics to identify avian individuals using a double‐marking experiment, whereby nine microsatellite genetic markers and natural markings on shed feathers were used to independently identify northern goshawks Accipiter gentilis. Phenotypic and genetic identification of individuals was consistent in 94.4% (51/54) comparisons. Our results suggest that the phenotypic characteristics of shed feathers can be reliably used as a non‐invasive and relatively inexpensive technique to monitor populations of an elusive species, the northern goshawk, without having to physically re‐capture or re‐sight individuals. We posit that using natural markings on shed feathers will also be a reliable method of identifying individuals in avian species with similar phenotypic characteristics, such as other Accipiter species. 相似文献
1000.
The sliding clamp proliferating cell nuclear antigen (PCNA) plays a vital role in a number of DNA repair pathways in eukaryotes and archaea by acting as a stable platform onto which other essential protein factors assemble. Many of these proteins interact with PCNA via a short peptide sequence known as a PIP (PCNA interacting protein) motif. Here we describe the identification and functional analysis of a novel PCNA interacting protein NreA that is conserved in the archaea and that has a PIP motif at its C‐terminus. Using the genetically tractable euryarchaeon Haloferax volcanii as a model system, we show that the NreA protein is not required for cell viability but that loss of NreA (or replacement of the wild‐type protein with a truncated version lacking the C‐terminal PIP motif) results in an increased sensitivity to the DNA damaging agent mitomycin C (MMC) that correlates with delayed repair of MMC‐induced chromosomal DNA damage monitored by pulsed‐field gel electrophoresis. Genetic epistasis analysis in Hfx. volcanii suggests that NreA works together with the UvrABC proteins in repairing DNA damage resulting from exposure to MMC. The wide distribution of NreA family members implies an important role for the protein in DNA damage repair in all archaeal lineages. 相似文献