Occurrence and antagonistic potential of Stenotrophomonas strains isolated from deep-sea invertebrates

Stenotrophomonas maltophilia is known to be of significance as opportunistic pathogen as well as a source of biocontrol and bioremediation activities. S. maltophilia strains have been isolated from rhizospheres, soil, clinical material, aquatic habitats, but little is known about Stenotrophomonas strains recovered from marine environments. During a survey of the biodiversity of Pseudomonas-like bacteria associated with deep-sea invertebrates six Stenotrophomonas strains were isolated from sponge, sea urchin, and ophiura specimens collected from differing Pacific areas, including the Philippine Sea, the Fiji Sea and the Bering Sea. 16S rRNA gene sequence analysis confirmed an assignment of marine isolates to the genus Stenotrophomonas as it placed four strains into the S. maltophilia CIP 60.77^T cluster and two related to the S. rhizophila DSM 14405^T. Together with a number of common characteristics typical of S. maltophilia and S. rhizophila marine isolates exhibited differences in pigmentation, a NaCl tolerance, a range of temperatures, which supported their growth, substrate utilization pattern, and antibiotics resistance. Strains displayed hemolytic and remarkable inhibitory activity against a number of fungal cultures and Gram-positive microorganisms, but very weak or none against Candida albicans. This is the first report on isolation, taxonomic characterization and antimicrobial activity of Stenotrophomonas strains isolated from deep-sea invertebrates.     

分蘖型谷子资源的表型和遗传多样性分析

本研究选用了来自国外及国内的68份分蘖型谷子进行了表型及遗传多样性分析。表型分析表明,质量性状以绿鞘、白谷黄米、圆锥穗、松散穗码居多,数量性状变异系数除出谷率较小外,其他性状表现了丰富的遗传变异,来自山西的小软谷单株穗重、单株穗粒重、千粒重均为最高,而来自黑龙江的大青谷单株穗粒重、出谷率、千粒重均为最低。遗传多样性分析结果表明,77对引物共检测出202个等位位点,每对引物可检测到1~6个位点不等,平均为2.62个;77对引物多态性信息含量(PIC)在0.0283~0.6974之间,平均多态性信息量(PIC)为0.4169,68份材料间的遗传相似系数变化范围为0.59~0.96,平均值为0.68。利用软件NTSYSpc 2.10的UPGMA聚类方法对68份谷子分蘖材料进行了聚类,这些材料被划分为4个类群,即Ⅰ、Ⅱ、Ⅲ和Ⅳ。Ⅰ类群主要来自西北地区谷子分蘖种质,Ⅱ类群主要来自国外谷子分蘖种质,Ⅲ类群包括华北、华东和东北的谷子分蘖种质,Ⅳ类群仅包括一个种质。结合表型鉴定出10份优势谷子分蘖种质。这些结果揭示68份谷子分蘖种质遗传多样性较好,研究结果为挖掘谷子分蘖优良基因及谷子分蘖育种提供理论依据。     

辽宁地区水稻资源抗稻瘟病基因的检测分析

为了明确辽宁地区水稻资源中抗稻瘟病基因的分布情况及抗病效应,选取辽宁地区水稻资源176份,鉴定了抗稻瘟病基因pi21、Pi36、Pi37、Pita、Pid2、Pid3、Pi5及Pib在这些材料中的分布情况,并接种鉴定了这些材料对稻瘟病的抗性。结果表明:176份供试材料中,83份对稻瘟病表现抗病,栽培稻、杂草稻及农家种中抗病品种所占的比率分别为41.48%、1.14%及4.54%。抗稻瘟病基因pi21、Pi36和Pi37在所有参试材料中均未检测到,且分别有74份、49份、47份、52份及89份材料携带Pita、Pid2、Pid3、Pi5及Pib的抗病等位基因。抗病基因绝大部分分布在栽培种中,农家种和杂草稻中分布较少。不含有抗稻瘟病基因和只携带单个抗病基因的材料对稻瘟病的抗性均较差,而抗病基因聚合可不同程度提高材料的抗性。经检测,不含有本试验鉴定的pi21等8个已克隆抗病基因的材料共32份,其中表现抗病的占21.87%;只携带1个抗稻瘟病基因的材料为52份,表现抗病的占17.31%;携带2个抗稻瘟病基因的材料为39份,表现抗病的占69.23%,其中以携带Pita+Pi5的材料最多(14份),且均表现抗病;携带3个抗稻瘟病基因的材料为31份,表现抗病的占77.42%,以携带Pita+Pid3+Pi5的材料抗性最强;携带4个抗稻瘟病基因的水稻材料22份,表现抗病的占72.73%,携带5个抗病基因的水稻材料未检测到。     

微卫星不稳定性的生物学意义及其应用前景

微卫星为遍布于人类基因组中的简单重复序列。在人群中,它们呈现高度多态性,并且稳定遗传。微卫星的高度多态性是微卫星不稳定性的表现,它与错配修复基因的缺陷有关。微卫星不稳定性已广泛应用于肿瘤学的研究,并依此提出了肿瘤发生的“增变基因”途径。     

基于语义的疾病表型相似性

已知一种药物可用于治疗某疾病,则该药物可能对与该疾病具有相似表型的其他疾病有疗效。因此,大规模地计算疾病表型相似性可辅助发现的疾病新的治疗方法。我们从OMIM下载了3742种疾病的表型信息,从Mesh词库下载13721个关联解剖学和疾病症状的注释词。我们将以上的Mesh词逐一在3742种疾病的表型信息文本中搜索,得到每种疾病涉及的Mesh词汇列表,进而基于语义分析的方法系统地计算了疾病表型的两两相似性矩阵。我们发现疾病关联生物通路最多的有肿瘤生物通路,胰岛素信号通路,肥大心肌病通路和细胞粘附通路等。随疾病对表型相似度的增加,其更涉及相同KEGG生物通路的概率亦增加,证明了本文方法的可靠性。疾病表型相似性可作为疾病在基因水平相似性的补充,有望为药物发现研究提供一条新途径。     

基于交叉抚育的雌性根田鼠对雄鼠尿气味的识别

通过交叉抚育建立同巢同胞、同巢非同胞、异巢同胞和异巢非同胞个体组成的室内繁殖种群,在断奶后（80日龄）分别取这些供体的新鲜尿作刺激物,在吕字型观察箱中观察和记录雌性根田鼠对雄鼠气味的行为响应,以研究根田鼠同胞识别的化学通讯机制。结果表明：（1）成年雌性根田鼠对雄性同巢同胞气味的接近潜伏期极显著短于对同巢非同胞气味的接近潜伏期（P〈0.01）,而其对两者的访问时间和嗅舔时间之间的差异并不显著（P〉0.05）;（2）雌鼠对雄性异巢同胞和异巢非同胞气味无明显偏好。其对两者的接近潜伏期、访问时间和嗅舔时间等行为响应均无显著差异（P〉0.05）;（3）雌鼠对雄性同巢非同胞和异巢非同胞的接近潜伏期差异并不明显（P〉0.05）,对两者访问时间和嗅舔时间的差别不大（P〉0.05）;（4）比较雌鼠对异巢同胞和同巢同胞气味的行为响应发现,其对后者的接近潜伏期显著短于前者（P〈0.05）,其对两者访问时间、嗅舔时间之间的差异未达到显著水平（P〉0.05）。这些结果表明,80日龄时,雌性根田鼠具有亲属识别能力,其同胞识别的机制可能为共生熟悉和表型匹配两种模式协同作用。     

植物基因克隆的策略和方法

本文介绍了功能克隆,定位克隆,表型克隆等９种克隆植物基因的方法,着重分析了每项克隆方法的工作原理,应用范围和进展     

The ALDH2 rs671 polymorphism is associated with athletic status and muscle strength in a Japanese population

Aldehyde dehydrogenase 2 (ALDH2) catalyses aldehyde species, including alcohol metabolites, mainly in the liver. We recently observed that ALDH2 is also expressed in skeletal muscle mitochondria; thus, we hypothesize that rs671 polymorphism-promoted functional loss of ALDH2 may induce deleterious effects in human skeletal muscle. We aimed to clarify the association of the ALDH2 rs671 polymorphism with muscle phenotypes and athletic capacity in a large Japanese cohort. A total of 3,055 subjects, comprising 1,714 athletes and 1,341 healthy control subjects (non-athletes), participated in this study. Non-athletes completed a questionnaire regarding their exercise habits, and were subjected to grip strength, 30-s chair stand, and 8-ft walking tests to assess muscle function. The ALDH2 GG, GA, and AA genotypes were detected at a frequency of 56%, 37%, and 7% among athletes, and of 54%, 37%, and 9% among non-athletes, respectively. The minor allele frequency was 25% in athletes and 28% in controls. Notably, ALDH2 genotype frequencies differed significantly between athletes and non-athletes (genotype: p = 0.048, allele: p = 0.021), with the AA genotype occurring at a significantly lower frequency among mixed-event athletes compared to non-athletes (p = 0.010). Furthermore, non-athletes who harboured GG and GA genotypes exhibited better muscle strength than those who carried the AA genotype (after adjustments for age, sex, body mass index, and exercise habits). The AA genotype and A allele of the ALDH2 rs671 polymorphism were associated with a reduced athletic capacity and poorer muscle phenotypes in the analysed Japanese cohort; thus, impaired ALDH2 activity may attenuate muscle function.     

一种挖掘关键基因的新方法及其应用(英文)

近来,人们发现从疾病相关基因中寻找关键基因对疾病的诊断和治疗很重要。癌相关基因的网络是根据正常和患病的胶质瘤组织的基因表达谱建立。根据建立的基因网络和CIPHER方法,不同阈值下的正常和患病的胶质瘤表型网络被建立。根据已知的疾病和表型间的关联,另一组正常和患病的胶质瘤表型网络被建立。将两种方法建立的相应的表型网络进行比较,匹配度最大时对应的阈值及基因和表型网络被确定。在此基础上,通过打分方法得到了7个关键基因:DMBT1,ERBB2,NF2,PDGFB,AR,ARAF和TP53。文献查询发现其中5个基因与胶质瘤的形成和发展密切相关。剩下两个基因中的ARAF也间接地参与胶质瘤形成。因此,这两个基因可能在胶质瘤的形成中起重要作用。这一预测仍需要实验验证。     

棉花枯萎病菌异核体不同核型分离子表观特性及其核DNA的RAPD分析

切割野生型棉花枯萎病菌Fusariumoxysporumf.sp.vasinfectum菌落的菌丝尖端,得到菌株Ag149,该菌株是一个异核体,其菌落出现明显角变,自角变处经单孢分离和继代培养,得到三种表观性状稳定的分离子Ag149-I、Ag149-II和Ag149-III。它们在色素产生、菌落质地、孢子产量以及致病性上存在明显差异,但对这三种核型分离子核DNA进行RAPD分析,未发现明显差异。