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951.
952.
Alcohol dehydrogenases (ADH) are a class of enzymes that catalyze the reversible oxidation of alcohols to corresponding aldehydes or ketones, by using either nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP), as coenzymes. In this study, a short-chain ADH gene was identified in Bombyx mori by 5'-RACE PCR. This is the first time the coding region of BmADH has been cloned, expressed, purified and then characterized. The cDNA fragment encoding the BmADH protein was amplified from a pool of silkworm cDNAs by PCR, and then cloned into E. coli expression vector pET-30a(+). The recombinant His-tagged BmADH protein was expressed in E. coli BL21 (DE3), and then purified by metal chelating affinity chromatography. The soluble recombinant BmADH, produced at low-growth temperature, was instrumental in catalyzing the ethanol-dependent reduction of NAD(+), thereby indicating ethanol as one of the substrates of BmADH. 相似文献
953.
Populations of Sinojackia rehderiana are highly threatened and have small and scattered distribution due to habitat fragmentation and human activities. Understanding changes in genetic diversity, the fine-scale spatial genetic structure (SGS) at different life stages and gene flow of S. rehderiana is critical for developing successful conservation strategies for fragmented populations of this endangered species. In this study, 208 adults, 114 juveniles and 136 seedlings in a 50 × 100-m transect within an old-growth forest were mapped and genotyped using eight microsatellite makers to investigate the genetic diversity and SGS of this species. No significant differences in genetic diversity among different life-history stages were found. However, a significant heterozygote deficiency in adults and seedlings may result from substantial biparental inbreeding. Significant fine-scale spatial structure was found in different life-history stages within 19 m, suggesting that seed dispersal mainly occurred near a mother tree. Both historical and contemporary estimates of gene flow (13.06 and 16.77 m) indicated short-distance gene dispersal in isolated populations of S. rehderiana. The consistent spatial structure revealed in different life stages is most likely the result of limited gene flow. Our results have important implications for conservation of extant populations of S. rehderiana. Measures for promoting pollen flow should be taken for in situ conservation. The presence of a SGS in fragmented populations implies that seeds for ex situ conservation should be collected from trees at least 19-m apart to reduce genetic similarity between neighbouring individuals. 相似文献
954.
Novel ordered hierarchical mesoporous/microporous carbon (OHMMC) derived from mesoporous titanium‐carbide/carbon composites was prepared for the first time by synthesizing ordered mesoporous nanocrystalline titanium‐carbide/carbon composites, followed by chlorination of titanium carbides. The mesostructure and microstructure can be conveniently tuned by controlling the TiC contents of mesoporous TiC/C composite precursor, and chlorination temperature. By optimal condition, the OHMMC has a high surface area (1917 m2g?1), large pore volumes (1.24 cm3g?1), narrow mesopore‐size distributions (centered at about 3 nm), and micropore size of 0.69 and 1.25 nm, and shows a great potential as electrode for supercapacitor applications: it exhibits a high capacitance of 146 Fg?1 in noaqueous electrolyte and excellent rate capability. The ordered mesoporous channel pores are favorable for retention and immersion of the electrolyte, providing a more favorable path for electrolyte penetration and transportation to achieve promising rate capability performance. Meanwhile, the micropores drilled on the mesopore‐walls can increase the specific surface area to provide more sites for charge storage. 相似文献
955.
956.
Tang TT Zhu ZF Wang J Zhang WC Tu X Xiao H Du XL Xia JH Dong NG Su W Xia N Yan XX Nie SF Liu J Zhou SF Yao R Xie JJ Jevallee H Wang X Liao MY Shi GP Fu M Liao YH Cheng X 《PloS one》2011,6(9):e24272
Objective
Animal studies suggest that regulatory T (Treg) cells play a beneficial role in ventricular remodeling and our previous data have demonstrated defects of Treg cells in patients with chronic heart failure (CHF). However, the mechanisms behind Treg-cell defects remained unknown. We here sought to elucidate the mechanism of Treg-cell defects in CHF patients.Methods and Results
We performed flow cytometry analysis and demonstrated reduced numbers of peripheral blood CD4+CD25+FOXP3+CD45RO−CD45RA+ naïve Treg (nTreg) cells and CD4+CD25+FOXP3+CD45RO+CD45RA− memory Treg (mTreg) cells in CHF patients as compared with non-CHF controls. Moreover, the nTreg/mTreg ratio (p<0.01), CD4+CD25+FOXP3+CD45RO− CD45RA+CD31+ recent thymic emigrant Treg cell (RTE-Treg) frequency (p<0.01), and T-cell receptor excision circle levels in Treg cells (p<0.01) were lower in CHF patients than in non-CHF controls. Combined annexin-V and 7-AAD staining showed that peripheral Treg cells from CHF patients exhibited increased spontaneous apoptosis and were more prone to interleukin (IL)-2 deprivation- and CD95 ligand-mediated apoptosis than those from non-CHF individuals. Furthermore, analyses by both flow cytometry and real-time polymerase chain reaction showed that Treg-cell frequency in the mediastinal lymph nodes or Foxp3 expression in hearts of CHF patients was no higher than that of the non-CHF controls.Conclusion
Our data suggested that the Treg-cell defects of CHF patients were likely caused by decreased thymic output of nascent Treg cells and increased susceptibility to apoptosis in the periphery. 相似文献957.
Han B Guo J Abrahaley T Qin L Wang L Zheng Y Li B Liu D Yao H Yang J Li C Xi Z Yang X 《PloS one》2011,6(2):e17236
Background
The great advances of nanomaterials have brought out broad important applications, but their possible nanotoxicity and risks have not been fully understood. It is confirmed that exposure of environmental particulate matter (PM), especially ultrafine PM, are responsible for many lung function impairment and exacerbation of pre-existing lung diseases. However, the adverse effect of nanoparticles on allergic asthma is seldom investigated and the mechanism remains undefined. For the first time, this work investigates the relationship between allergic asthma and nanosized silicon dioxide (nano-SiO2).Methodology/Principal Findings
Ovalbumin (OVA)-treated and saline-treated control rats were daily intratracheally administered 0.1 ml of 0, 40 and 80 µg/ml nano-SiO2 solutions, respectively for 30 days. Increased nano-SiO2 exposure results in adverse changes on inspiratory and expiratory resistance (Ri and Re), but shows insignificant effect on rat lung dynamic compliance (Cldyn). Lung histological observation reveals obvious airway remodeling in 80 µg/ml nano-SiO2-introduced saline and OVA groups, but the latter is worse. Additionally, increased nano-SiO2 exposure also leads to more severe inflammation. With increasing nano-SiO2 exposure, IL-4 in lung homogenate increases and IFN-γ shows a reverse but insignificant change. Moreover, at a same nano-SiO2 exposure concentration, OVA-treated rats exhibit higher (significant) IL-4 and lower (not significant) IFN-γ compared with the saline-treated rats. The percentages of eosinophil display an unexpected result, in which higher exposure results lower eosinophil percentages.Conclusions/Significance
This was a preliminary study which for the first time involved the effect of nano-SiO2 to OVA induced rat asthma model. The results suggested that intratracheal administration of nano-SiO2 could lead to the airway hyperresponsiveness (AHR) and the airway remolding with or without OVA immunization. This occurrence may be due to the Th1/Th2 cytokine imbalance accelerated by the nano-SiO2 through increasing the tissue IL-4 production. 相似文献958.
Background
Co-infection with HIV and HCV and/or HBV is highly prevalent in intravenous drug users (IDUs). Because of the proximity to the “Golden Triangle”, HIV prevalence among the IDUs is very high in the China-Myanmar border region. However, there are few studies about co-infection with HIV and HCV and/or HBV, especially in the region that belongs to Myanmar.Methods
721 IDUs, including 403 Chinese and 318 Burmese, were investigated for their HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) serological status. Statistical analysis was performed to evaluate the differences of the epidemic situation between the Chinese IDUs and the Burmese IDUs.Results
Among the Chinese IDUs and the Burmese IDUs, HCV infection was the most prevalent (69.0% vs 48.1%, P<0.001), followed by HBV (51.6% vs 43.1%, P<0.05) and HIV (33.7% vs 27.0%, P>0.05). Besides, there were more HIV-HBV co-infected IDUs (20.1% vs 11.3%, P<0.005), and HIV-HCV co-infected IDUs (31.8% vs 23.9%, P<0.05) in China than in Myanmar, as well as HIV-HBV-HCV triple infection (19.1% vs 10.4%, P<0.005).Conclusion
Co-infection with HIV and HCV and/or HBV is highly prevalent among the IDUs in the China-Myanmar border region. The HIV epidemic appears to be in a downward trend, compared with previous reports. However, all infections were more prevalent among the Chinese IDUs than among the Burmese. 相似文献959.
960.
Jin-Biao Liu Xian-Yong Lan Yao Xu Zhuan-Jian Li Chu-Zhao Lei Hong Chen 《Genes & genomics.》2011,33(5):549-556
In this study, single nucleotide polymorphisms (SNPs) of LHX3 gene were detected by DNA sequencing based on DNA pools and PCR-RFLP method in 792 goats belonging to three Chinese indigenous breeds (Guanzhong dairy, Xinong Sannen dairy, Inner Mongolia white cashmere). The results revealed three novel mutations (AY923832:g.7778A>T; g.8035T>C; g.10592C>T), which were named as P2-DraI, P3-HinfI and P4-MspI loci, respectively. The linkage disequilibrium analysis demonstrated P3-HinfI and P4-MspI loci were strongly linked (r 2>0.33) in all the analyzed populations. Each SNP produced no significant (p>0.05) effects on milk performance. However, the two-loci and three-loci combined genotypes had more profound impacts on milk yield than in separation. The individuals with diplotype AATT (P2-DraI/P3-HinfI) showed significantly (p<0.05) higher milk yield than those with diplotypes ATTT, TTTT, ATTC, and AACC. Diplotype TTCCTT (P2-DraI/P3-HinfI/P4-MspI) carriers had significantly (p< 0.05) higher milk yield than those with diplotypes ATTTCC and AACCTC. These combined effects of LHX3 gene polymorphisms indicated that this gene had significant effect on milk performance and its corresponding combined diplotypes could be regarded as potential genetic markers of milk performance. 相似文献