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41.
42.
利用微卫星标记分析核盘菌遗传多样性   总被引:1,自引:0,他引:1  
利用微卫星(SSR)标记,分析来自欧洲和中国的30个核盘菌菌株的遗传多样性和群体结构。结果表明,3对微卫星引物共扩增出21条清晰的谱带,平均每对引物扩增7条谱带,片段长度为158bp~358bp。根据SSR分析结果,30个核盘菌分离物具有较高的遗传相似性。物种水平的Nei遗传多样性指数为0.139 3,Shannon多样性指数为0.248 8。不同菌株群体的Nei遗传距离都较小,为0.009 6~0.049 6。其中俄罗斯群体和奥地利及英国群体之间的遗传距离最大。从30个菌株的UPGMA聚类分析结果看,核盘菌群体结构与地理来源没有明显的直接关系。许多地理来源相同的菌株分散在不同的组里。仅第三组组内的菌株地理来源一致,均来自于中国,且遗传距离比其他菌株的远。群体遗传分析显示,总群体的基因流比较高(2.111 6),基因分化系数比较低(0.191 5)。  相似文献   
43.
Spectroscopic techniques including X-ray photoelectron spectroscopy (XPS) can identify particular chemical groups of humic acids (HA) from “Terra Preta de Índios” (TPI) or Amazonian dark earth, the highly fertile anthropogenic soil found in the Amazonian region. The high fertility and resilience of these soils cannot be explained by their chemically inert pyrogenic C content alone, but the natural aging of this C generates reactive carboxyl functional groups attached directly to the recalcitrant polycondensed aromatic backbone. Through spectroscopic techniques used in this work, the HA fraction (the alkaline-soluble organic matter that precipitates at low pH) of the TPI soil was compared with humic and fulvic acids, obtained by oxidizing activated charcoal with sodium hypochlorite. The yields recovery of HA-like substances was 12 and 28 wt% by using 10 and 20 cmol L?1 of oxidizing agent, respectively. X-ray photoelectron spectroscopy, energy dispersive X-ray, and solid-state 13C nuclear magnetic resonance (13C NMR) spectroscopies were used to evaluate the elements and structures present in all samples. XPS C 1 s spectra of HA extracted from TPI soil and from prepared HA showed aromatic structures (C?=?C and π–π* shake-up satellite peak) bounded to carboxyl groups (COOH). The morphology and polycondensation level of aromatic C were evaluated by scanning electron microscopy (SEM). The similarities of the spectra indicated that the used method was efficient to obtain an organic amendment similar to TPI soil organic matter.  相似文献   
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This study examined the influence of sex steroid hormones on lipid metabolism in horses. The group of 34 clinically healthy Standardbred trotters aged 2 to 4 years was studied during an exercise test. The horses were divided into groups according to their sex. These groups were: 11 stallions, 16 mares, and seven geldings. Concentrations of testosterone, 17-β-estradiol, leptin, ghrelin, glycerol, free fatty acids (FFA), and triacylglycerols (TG) were measured in plasma obtained from blood samples taken at rest and after the end of the exercise. At rest, plasma ghrelin concentration was significantly higher in geldings than in stallions and mares (1,541 ± 206 vs 1,280 ± 288 and 1,310 ± 267 pg/mL, respectively; P = .012). Leptin was lower in geldings than in mares (2.65 ± 0.93 vs 4.70 ± 2.31 ng/mL; P = .036). The post-exercise rise in plasma ghrelin and TG concentrations was significantly higher in mares than in geldings (+220 ± 330 vs -25 ± 206 pg/mL; P = .049 and 0.31 ± 0.14 vs 0.13 ± 0.15 mmol/L; P = .016, respectively). The increase in plasma FFA level was higher in geldings than in stallions (535 ± 178 vs 334 ± 191 μmol/L, P = .046). In conclusion, lipolysis rate in geldings is higher than in noncastrated trotters.  相似文献   
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