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1.

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.
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.
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.

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.
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.

Context

The relations between dietary and/or circulating levels of fatty acids and the development of type 2 diabetes is unclear. Protective associations with the marine omega-3 fatty acids and linoleic acid, and with a marker of fatty acid desaturase activity delta-5 desaturase (D5D ratio) have been reported, as have adverse relations with saturated fatty acids and D6D ratio.

Objective

To determine the associations between red blood cell (RBC) fatty acid distributions and incident type 2 diabetes.

Design

Prospective observational cohort study nested in the Women’s Health Initiative Memory Study.

Setting

General population.

Subjects

Postmenopausal women.

Main Outcome Measures

Self-reported incident type 2 diabetes.

Results

There were 703 new cases of type 2 diabetes over 11 years of follow up among 6379 postmenopausal women. In the fully adjusted models, baseline RBC D5D ratio was inversely associated with incident type 2 diabetes [Hazard Ratio (HR) 0.88, 95% confidence interval (CI) 0.81–0.95) per 1 SD increase. Similarly, baseline RBC D6D ratio and palmitic acid were directly associated with incident type 2 diabetes (HR 1.14, 95% CI 1.04–1.25; and HR 1.24, 95% CI 1.14–1.35, respectively). None of these relations were materially altered by excluding incident cases in the first two years of follow-up. There were no significant relations with eicosapentaenoic, docosahexaenoic or linoleic acids.

Conclusions

Whether altered fatty acid desaturase activities or palmitic acid levels are causally related to the development of type 2 diabetes cannot be determined from this study, but our findings suggest that proportions of certain fatty acids in RBC membranes are associated with risk for type 2 diabetes.  相似文献   
8.
9.
IntroductionEpidemiological studies suggest that reduced intakes and/or blood levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are associated with increased risk for depression in adults, but data on adolescents are scarce. The objective of this study was to determine whether red blood cell (RBC) levels of EPA+DHA (the omega-3 index) and/or the overall RBC fatty acid profile differ between depressed adolescents (cases) and non-depressed adolescents (controls).Patients and MethodsWe measured the RBC fatty acid composition of cases admitted to the hospital for depression (n=150) and compared it to that of controls (n=161).ResultsCases and controls had similar ages, gender proportions, and body mass index (BMI) distributions, but there was a significant difference in racial/ethnic composition due to differences in recruitment sites. The unadjusted odds ratio for case status was 0.72 (95% CI; 0.55–0.95) for a 1% absolute increase in the omega-3 index. A multivariable logistic regression model was used to determine which fatty acids were useful in classifying cases and controls; BMI, age, gender, and race/ethnicity were forced into the model. Seven fatty acids were selected (DHA, myristic, stearic, oleic, trans linoleic, trans palmitoleic, and alpha-linolenic acids) to optimize the model fit to the data. In the adjusted model, the odds ratio was 0.67 (95% CI; 0.49–0.93) for a 1 SD increase in DHA. Adding the seven fatty acid profile to the basic model increased the area under the ROC curve by 12.6% (7.5%–17.6%).Discussion and ConclusionThese findings support the hypothesis that adolescent depression is associated with a perturbed RBC fatty acid pattern which includes a reduced omega-3 index. Intervention studies with EPA and DHA should be conducted in this vulnerable population for which few, safe therapeutic options currently exist.  相似文献   
10.
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cry26Aacry28Aa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cry26Aacry28Aa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   
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