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1.
Beste DJ Hooper T Stewart G Bonde B Avignone-Rossa C Bushell ME Wheeler P Klamt S Kierzek AM McFadden J 《Genome biology》2007,8(5):R89
Background
An impediment to the rational development of novel drugs against tuberculosis (TB) is a general paucity of knowledge concerning the metabolism of Mycobacterium tuberculosis, particularly during infection. Constraint-based modeling provides a novel approach to investigating microbial metabolism but has not yet been applied to genome-scale modeling of M. tuberculosis. 相似文献2.
JI Priego AG Lucas-Cuevas I Aparicio JV Giménez JM Cortell-Tormo P Pérez-Soriano 《Biology of sport / Institute of Sport》2015,32(3):219-223
The use of graduated compression stockings (GCS) in sport has been increasing in the last years due to their potential positive effects for athletes. However, there is little evidence to support whether these types of garments actually improve cardiorespiratory performance. The aim of this study was to examine the cardiorespiratory responses of GCS during running after three weeks of regular use. Twenty recreational runners performed three tests on different days: test 1) – a 5-min maximal effort run in order to determine the participants’ maximal aerobic speed; and tests 2) and 3) – a fatigue running test of 30 minutes at 80% of their maximal aerobic speed with either GCS or PLACEBO stockings at random. Cardiorespiratory parameters (minute ventilation, heart rate, relative oxygen consumption, relative carbon dioxide production, ventilatory equivalents for oxygen and carbon dioxide, and oxygen pulse) were measured. Before each test in the laboratory, the participants trained with the randomly assigned stockings (GCS or PLACEBO) for three weeks. No significant differences between GCS and PLACEBO were found in any of the cardiorespiratory parameters. In conclusion, the present study provides evidence that running with GCS for three weeks does not influence cardiorespiratory parameters in recreational runners. 相似文献
3.
M Montenegro S Llambí G Castro N Barlocco A Vadell V Landi JV Delgado A Martínez 《Genetics and molecular biology》2015,38(1):48-54
In this study, we genetically characterized the Uruguayan pig breed Pampa Rocha.
Genetic variability was assessed by analyzing a panel of 25 microsatellite markers
from a sample of 39 individuals. Pampa Rocha pigs showed high genetic variability
with observed and expected heterozygosities of 0.583 and 0.603, respectively. The
mean number of alleles was 5.72. Twenty-four markers were polymorphic, with 95.8% of
them in Hardy Weinberg equilibrium. The level of endogamy was low (FIS =
0.0475). A factorial analysis of correspondence was used to assess the genetic
differences between Pampa Rocha and other pig breeds; genetic distances were
calculated, and a tree was designed to reflect the distance matrix. Individuals were
also allocated into clusters. This analysis showed that the Pampa Rocha breed was
separated from the other breeds along the first and second axes. The
neighbour-joining tree generated by the genetic distances DA showed
clustering of Pampa Rocha with the Meishan breed. The allocation of individuals to
clusters showed a clear separation of Pampa Rocha pigs. These results provide
insights into the genetic variability of Pampa Rocha pigs and indicate that this
breed is a well-defined genetic entity. 相似文献
4.
Evidence for selection on synonymous mutations affecting stability of mRNA secondary structure in mammals
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Background
In mammals, contrary to what is usually assumed, recent evidence suggests that synonymous mutations may not be selectively neutral. This position has proven contentious, not least because of the absence of a viable mechanism. Here we test whether synonymous mutations might be under selection owing to their effects on the thermodynamic stability of mRNA, mediated by changes in secondary structure. 相似文献5.
糖尿病微血管病变严重影响了患者生活质量,是患者致死致残主要原因。微血管病变主要表现在视网膜、肾、神经、心肌组织。微血管病变的机制尚未完全清楚,近年越来越多研究发现血管内皮祖细胞(endothelial progenitor cells,EPCs)是该病发病重要原因。EPCs有分化为成熟的内皮细胞并且参与新血管形成和新生的能力。正常情况下内皮损失和EPCs对内皮的修复作用处于动态平衡状态,一旦EPCs受损,内皮损害和修复之间的平衡被打破,内皮层的完整性遭到破坏,必然参与糖尿病血管病变的发生发展。国内外大量研究证明糖尿病合并大血管病变EPCs数目功能改变,而糖尿病合并微血管病变EPCs的怎样变化?本文就EPCs与糖尿病微血管病变的关系进行系统综述。 相似文献
6.
CTS Silva V. Wanderley-Teixeira FM Cunha JV Oliveira KA Dutra DMA Ferraz Navarro 《Biotechnic & histochemistry》2018,93(1):36-48
The armyworm, Spodoptera frugiperda, is the principal pest of corn in Brazil. Control is achieved primarily by synthetic insecticides, which cause problems for the agro-ecosystem. Alternative methods of control are under investigation and citronella (Cymbopogon winterianus) essential oil appears to be a promising agent. We investigated the effects of citronella oil using histological, histochemical and immunohistochemical methods. The midgut of larvae treated with citronella exhibited altered epithelium including cytoplasmic protrusions, columnar cell extrusion, pyknotic nuclei, and increased periodic acid-Schiff positive granules. Regenerative cells in the epithelium of the midgut increased in number, which facilitated subsequent regeneration of this tissue. After exposure to citronella, trophocytes, the principal cell type of the fat body, possessed enlarged vacuoles and mitotic bodies, and contained reduced amounts of glycogen, lipid, and protein. Citronella oil caused morphological changes of the midgut and reduction of stored resources in the fat body, which may adversely affect insect reproduction and survival. 相似文献
7.
Two groups recently argued that, in human genes, synonymous sites near intron-exon junctions undergo selection for correct splicing. However, neither study controlled for the possibility of an underlying nucleotide bias at the ends of exons. In this article, we show that generalized A and T enrichment exists, which could be independent of splicing regulation. Evidence for selection between synonymous codons that are associated with splicing enhancers remains after controlling for this bias, whereas support for cryptic splice-site avoidance is diminished. 相似文献
8.
TJS Alves GS Cruz V Wanderley-Teixeira AAC Teixeira JV Oliveira AA Correia 《Biotechnic & histochemistry》2014,89(4):245-255
The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), not only damages crops, but controlling its population also requires synthetic insecticides, which leads to selection of resistant populations and environmental contamination. Essential oils are an alternative for controlling this insect. There are few studies of the effects of these oils on the insect's reproductive system. We evaluated the effects of the long pepper, Piper hispidinervum, essential oil on the gonads of the armyworm and tested its possible influence on the fertility of this insect. Dosages of 30 and 50 mg/ml were tested in 3rd instar caterpillars using the leaf immersion method. Testes and ovarioles were collected, fixed with 10% formalin and embedded in Historesin. The sections were stained with toluidine blue and Mallory trichrome to detect connective tissue, periodic acid-Schiff to detect neutral carbohydrates, and bromophenol blue to detect proteins. We found that the long pepper essential oil affected negatively the spermatogenesis and altered the histochemistry of the ovarioles of S. frugiperda. The effects of long pepper oil suggest that it is a promising tool for controlling the armyworm pest. 相似文献
9.
苏云金芽胞杆菌幕虫亚种T02菌株的伴胞晶体在芽胞外壁内侧形成,呈现晶胞粘连的现象。在此菌株中克隆了cry26Aa和cry28Aa两个基因,并对晶胞粘连现象与质粒的相关性做了系统研究。通过消除幕虫亚种T02菌株的质粒,得到了仅消除cry26Aa所在质粒的菌株BMB1151和无质粒的菌株BMB1152。通过穿梭载体将cry26Aa和cry28Aa两个基因分别和同时转化无质粒突变株BMB1152并表达,形成的晶体与芽胞独立存在不能粘连,表明在幕虫亚种染色体背景下仅仅cry的表达不能形成晶胞粘连现象,从而推断晶胞粘连现象可能与幕虫亚种两个基因所在的质粒有关;进一步的研究发现将cry26Aa在仅消除cry26Aa所在质粒的突变株BMB1151中表达,形成的晶体与芽胞也分别独立存在不能粘连,从而进一步推断幕虫亚种晶胞粘连现象与cry26Aa所在质粒有关。 相似文献
10.
Evidence for purifying selection against synonymous mutations in mammalian exonic splicing enhancers
Silent sites in mammals have classically been assumed to be free from selective pressures. Consequently, the synonymous substitution rate (Ks) is often used as a proxy for the mutation rate. Although accumulating evidence demonstrates that the assumption is not valid, the mechanism by which selection acts remain unclear. Recent work has revealed that the presence of exonic splicing enhancers (ESEs) in coding sequence might influence synonymous evolution. ESEs are predominantly located near intron-exon junctions, which may explain the reduced single-nucleotide polymorphism (SNP) density in these regions. Here we show that synonymous sites in putative ESEs evolve more slowly than the remaining exonic sequence. Differential mutabilities of ESEs do not appear to explain this difference. We observe that substitution frequency at fourfold synonymous sites decreases as one approaches the ends of exons, consistent with the existing SNP data. This gradient is at least in part explained by ESEs being more abundant near junctions. Between-gene variation in Ks is hence partly explained by the proportion of the gene that acts as an ESE. Given the relative abundance of ESEs and the reduced rates of synonymous divergence within them, we estimate that constraints on synonymous evolution within ESEs causes the true mutation rate to be underestimated by not more than approximately 8%. We also find that Ks outside of ESEs is much lower in alternatively spliced exons than in constitutive exons, implying that other causes of selection on synonymous mutations exist. Additionally, selection on ESEs appears to affect nonsynonymous sites and may explain why amino acid usage near intron-exon junctions is nonrandom. 相似文献