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41.
Phylogeography of island canary (Serinus canaria) populations   总被引:2,自引:2,他引:0  
Island canaries (Serinus canaria) are characterised as a species living exclusively on North Atlantic islands, mainly on the Azores, Madeira and Canary Islands. Although they are very common in their habitats, their behaviour and breeding system has only recently been studied systematically. To advance the understanding of their ecology and to see if the rather isolated archipelagos are already promoting a genetic differentiation, we investigated their phylogeographic relationship as revealed by mtDNA sequences of the cytochrome b gene and investigated whether this measure corresponds to morphological characteristics within the islands. Genetic distances were very low throughout the distribution range of the species. Although the variation of genetic distances within the population of Pico (Azores) was larger than that on Madeira and Canary Islands, the genetic distances between island populations were very low throughout which prevented a clear phylogeographic differentiation. Moreover, morphological measurements did not reveal a consistent pattern to reliably separate the populations, although the measures of beak length and body weight revealed a clear island-specific differentiation. These data lead to the assumption that the colonisation of the Atlantic islands by the canaries occurred very recently, while there is no persisting gene flow between the populations.  相似文献   
42.
摘要 目的:探讨胆囊结石患者结石形态学特征及血浆脂多糖(LPS)水平与急性胆源性胰腺炎(ABP)的关系。方法:选取2015年10月~2018年9月期间武汉大学人民医院收治的胆囊结石患者164例为研究对象,分析结石形态学特征与并发ABP的关系,同时采用Logistic回归分析ABP发生的危险因素。将所有患者根据LPS水平分为低LPS组(n=65,<10 pg/mL)以及高LPS组(n=99,≥10 pg/mL),分析血浆LPS水平对不同结石大小、不同总胆固醇(TG)水平患者并发ABP的影响。结果:多发胆囊结石、球状结石、<3 mm结石、软碎型结石患者并发ABP的概率明显高于单发胆囊结石、不规则状结石或泥沙状结石、3~10 mm结石或>10 mm结石、硬型结石或胶冻型结石(P<0.05)。Logistic回归分析结果显示,多发胆囊结石、球状结石、<3 mm结石以及软碎型结石均是ABP发生的高危因素(P<0.05)。当患者处于高TG水平时,高LPS组并发ABP的概率高于低LPS组(P<0.05),在细小结石患者中,高LPS组并发ABP的概率高于低LPS组(P<0.05)。结论:依据结石形态学特征可对胆囊结石患者并发ABP的可能性作出早期的判断,同时血浆LPS水平升高是高TG以及细小胆囊结石患者易并发ABP的重要因素之一。  相似文献   
43.
The increasingdemandfor biopharmaceutical products drives the search for efficient cell factories that are able to sustainably support rapid growth, high productivity, and product quality. As these depend on energy generation, here the genomic variation in nuclear genes associated with mitochondria and energy metabolism and the mitochondrial genome of 14 cell lines is investigated. The variants called enable reliable tracing of lineages. Unique sequence variations are observed in cell lines adapted to grow in protein‐free media, enriched in signaling pathways or mitogen‐activated protein kinase 3. High‐producing cell lines bear unique mutations in nicotinamide adenine dinucleotide (NADH) dehydrogenase (ND2 and ND4) and in peroxisomal acyl‐CoA synthetase (ACSL4), involved in lipid metabolism. As phenotypes are determined not only by functional mutations, but also by the exquisite regulation of expression patterns, it is not surprising that ≈50% of the genes investigated here are found to be differentially methylated and thus epigenetically controlled, enabling a clear distinction of high producers, and cells adapted to a minimal, glutamine (Gln)‐free medium. Similar pathways are enriched as those identified by genome variation. This strengthens the hypothesis that these phenomena act together to define cell behavior.  相似文献   
44.
45.
斑鲆属(Pseudorhombus, Bleeker, 1862)隶属于鲽形目(Pleuronectiforms)牙鲆科(Paralichthyidae),根据Eschmeyer’s Catalog of Fishes记录有效种类有25种;根据李思忠等(1995)的《中国动物志:硬骨鱼纲 鲽形目》记载,目前在中国大陆海域有标本记录的有11种。本研究在2007年到2021年在海南的文昌、陵水和三亚分别采集到了9尾有眼侧有5个眼状斑纹的标本,并和该属25种鱼类的原始形态特征进行了比较。比对结果发现,该样品符合Amaoka(1969)定名的卷眼斑鲆(P. oculocirris Amaoka, 1969)形态特征。该种类目前只在日本和越南有报道,本研究是首次在中国大陆海域采集,故为新记录种。本研究结合卷眼斑鲆原始描述、相关文献和采集到的9尾标本的形态特征对该种类进行了详细的再描述,并首次提供了线粒体分子条形码(GenBank登录号为OL307681、OL307682和OL307683)。该种的主要形态特征为背鳍65–76;臀鳍50–57;有眼侧胸鳍11–13,无眼侧胸鳍10–12;尾鳍条2 + 13 + 2;第一鳃弓鳃耙4–7 + 17–20;侧线鳞71–82;脊椎骨10 + 26 = 36;背鳍前边几个鳍条稍长且基部只有1/5–1/3连有鳍膜,下眼上缘具有指状皮突。本研究的发现进一步扩大了该种的分布范围和提供了种类鉴定的分子依据,本报道将会为牙鲆科鱼类生物多样性和系统演化研究提供科学依据。  相似文献   
46.
赵正嫄  张云龙  李婷  吕一河  王聪  伍星 《生态学报》2022,42(18):7403-7416
生态敏感性是生态系统对外界压力的适应性及遭受破坏的恢复力,开展生态敏感性评价是识别区域生态环境问题的有效手段之一。根据青藏高原的区域特性和主要生态环境问题,在定量构建土地荒漠化敏感性、水土流失敏感性、滑坡灾害敏感性和冻融侵蚀敏感性的基础上,通过空间距离指数法对青藏高原生态敏感性进行综合评价,并采用空间自相关分析和生态敏感性变化模式分析,探讨其时空演变特征和保护管理区划。结果表明:(1)青藏高原综合生态敏感性由西北向东南递减,极度和重度敏感区主要集中在西北部和高大山脉区,不敏感区主要集中在东南部;(2)2000-2018年间青藏高原综合生态敏感性指数值从1.49上升到1.51,表明该区域生态敏感性逐步下降,生态环境改善明显;(3)青藏高原生态敏感性存在显著的空间正相关,低-低聚集网格数量波动上升,从2000年的7277增至2018年7357,表明青藏高原部分地区的生态环境仍存在着一定恶化的风险;(4)根据区域生态敏感性变化模式分析,将青藏高原划分为严格保护区、生态退化区、潜在治理区、生态改善区和综合发展区五个区域,并提出了相应保护与管理对策。研究结果可以为青藏高原生态保护和可持续发展提供参考,从而有效推动保护管理措施的制定。  相似文献   
47.
《Fungal biology》2022,126(5):333-341
Dendrobium officinale (Orchidaceae) is a traditional Chinese medicinal plant. Its growth is slow, however many dark septate endophytic fungi (DSEs) are considered useful to plant growth and as biocontrol agents against plant pathogens. The goals of this study were to identify a new DSE and evaluate its plant-growth promotion characteristics. Based on morphological and molecular phylogenetic evidence, a DSE fungal strain TK815 isolated from Dashiwei Tiankengs in Leye county Guangxi Province, China, was classified as a novel genus in the order Cheatothyriales, namely Tiankengomelania gen. nov. typified with T. guangxiense sp. nov. Tiankengomelania guangxiense TK815 can significantly promote the growth of D. officinale in stem length (11.25%), seedling height (16.97%), root length (10.34%), and dry weight (41.05%). This study discovered, described, and illustrated a new DSE fungus, and evaluated its biological function in contributing to the growth and production of the Chinese medicinal plant D. officinale.  相似文献   
48.
This special focus issue of Expert Review of Proteomics invites key opinion leaders to report their recent findings and views on the important topic of translating potential proteomic biomarkers to clinically useful, regulator-approved biomarkers: a challenging journey. The issue also highlights the difficulties associated with and the way forward in the discovery of proteomic cancer biomarkers for clinical applications, as well as presenting recent original research in the field.  相似文献   
49.
重庆大豆地方资源多样性评价及群体表型特点研究   总被引:1,自引:0,他引:1  
对收集于重庆市的103份大豆地方品种进行了表型遗传多样性分析,并利用主成分分析和聚类分析对其进行了群体表型特点的研究,研究结果表明,重庆地区大豆地方种质资源以灰色茸毛、黄粒、褐色脐居多,个体之间数量性状上存在较大变异。主成分分析以3个主成分反映了10个农艺性状的大部分信息,将主要农艺性状归纳成产量因子、生长势因子及籽粒因子。聚类分析将103份地方种质资源聚为6个类群, 同一地区的大部分地方品种表现较为相似,少部分地方品种差异大,品种类群间的表型分化与地理分布既有一定的联系又不绝对相关。利用这些种质选配育种亲本应关注各类群间性状差异作选择,而不能仅关注地理来源选择。  相似文献   
50.
Three yeast cytochrome c peroxidase (CcP) variants with apolar distal heme pockets have been constructed. The CcP variants have Arg48, Trp51, and His52 mutated to either all alanines, CcP(triAla), all valines, CcP(triVal), or all leucines, CcP(triLeu). The triple mutants have detectable enzymatic activity at pH 6 but the activity is less than 0.02% that of wild-type CcP. The activity loss is primarily due to the decreased rate of reaction between the triple mutants and H2O2 compared to wild-type CcP. Spectroscopic properties and cyanide binding characteristics of the triple mutants have been investigated over the pH stability region of CcP, pH 4 to 8. The absorption spectra indicate that the CcP triple mutants have hemes that are predominantly five-coordinate, high-spin at pH 5 and six-coordinate, low-spin at pH 8. Cyanide binding to the triple mutants is biphasic indicating that the triple mutants have two slowly-exchanging conformational states with different cyanide affinities. The binding affinity for cyanide is reduced at least two orders of magnitude in the triple mutants compared to wild-type CcP and the rate of cyanide binding is reduced by four to five orders of magnitude. Correlation of the reaction rates of CcP and 12 distal pocket mutants with H2O2 and HCN suggests that both reactions require ionization of the reactants within the distal heme pocket allowing the anion to bind the heme iron. Distal pocket features that promote substrate ionization (basic residues involved in base-catalyzed substrate ionization or polar residues that can stabilize substrate anions) increase the overall rate of reaction with H2O2 and HCN while features that inhibit substrate ionization slow the reactions.  相似文献   
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