武汉市桔梗科一物种新记录——卵叶异檐花

报道了武汉市外来入侵植物新记录一种,为桔梗科Campanulaceae异檐花属Triodanis卵叶异檐花Triodanis perfoliata subsp.biflora(Ruiz et Pavon)Lammers。卵叶异檐花原产于美洲,在武汉地区是首次发现,凭证标本保存于长江文明馆(武汉自然博物馆)。     

大白菜软腐病菌游动性突变体在大白菜体内增殖扩展研究

 用培养皿滤纸吸附测定法和不伤根土壤拌菌处理及针刺接种法,测定了大白菜软腐病菌游动性突变体进入大白菜体内、并在其中侵染定殖和扩展的特性。结果表明,游动性丧失和增强的突变体都可以通过种子萌发和主动接触进入大白菜体内、并可以在体内有短期的繁殖,但菌量远低于野生菌。大白菜叶片接种实验说明,这两种突变体也都可以进行短距离扩展,但扩展距离和菌的繁殖量低于野生菌。     

Homolog of FlhDC, a master regulator for flagellum synthesis: required for pathogenicity in Erwinia carotovora subsp. carotovora

 Erwinia carotovora subsp. carotovora (Ecc) is a causal agent of soft-rot diseases in a wide variety of plants. Here, we have isolated nonmotile mutants in Ecc by in vivo insertional mutagenesis using a transposon Tn5. The sequence disrupted by the Tn5 insertion in YMU1 and YMU5 mutants was highly homologous to that of flhC and flhD genes, respectively. They are involved in the initiation of the expression of flagellum-related genes in many gram-negative bacteria such as Escherichia coli and Salmonella. With electron microscopy, the flhC and the flhD homolog mutants were shown to be aflagellate. Furthermore, the virulence of these mutants was greatly reduced in Chinese cabbage and potato compared to that of the parental strain. These results suggest that flagellar formation is required for the pathogenicity of Ecc. Received: November 5, 2002 / Accepted: December 2, 2002 Acknowledgments This research was supported in part by Grant-in-Aid (12052210) and by a grant from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (13073).     

丝状霉形体丝状亚种SC型脂蛋白LppQ N末端基因克隆与序列分析

脂蛋白LPPQ是丝状霉形体丝状亚种SC型(MmmSC)非洲株、欧洲株和疫苗株所特有的。LPPQ N末端域具有良好的免疫原性，在牛体内可诱导产生强大、特异、早期、持续的免疫反应。本研究根据已发表的LPPQ基因序列设计引物，用Pyrobest^TM高保真DNA聚合酶从MmmSC HVRI X株中扩增出了LPPQ N末端基因序列，并进行了克隆与序列测定。核苷酸序列比较结果显示，HVRI X株的LPPQ N末端基因序列与国外发表的序列同源性为99．7％，由其推导的氨基酸序列同源性为99，1％，为脂蛋白LPPQ N末端基因体外表达奠定了基础。     

半滑舌鳎源美人鱼发光杆菌美人鱼亚种的分离鉴定

2016年5月河北省秦皇岛市昌黎县某海水养殖基地半滑舌鳎突发大批死亡,为了确定引起死亡的病原菌,无菌采集心血进行病原菌分离鉴定,16S rDNA基因序列分析与GenBank中公布的美人鱼发光杆菌参考株序列同源性为99.6%,被鉴定为美人鱼发光杆菌;进一步通过生化特性分析,被确认为美人鱼发光杆菌美人鱼亚种。动物回归试验结果表明,其对舌鳎鱼具有很强的致病性,其LD_(50)为3.1×10~4CFU/mL,且对哺乳动物具有致病性。药敏试验结果显示,分离菌对诺氟沙星、恩诺沙星、环丙沙星,乙酰甲喹高度敏感;对多西环素、阿米卡星中敏感;对庆大霉素、头孢曲松、替米考星等不敏感。     

籼稻体细胞胚胎发生特异性蛋白质研究

以籼稻Oryza sativa L.subsp. indica品种“广陆矮4号”幼穗和种子为外植体，在含有2，4-D2.0mg/L的MS培养基上，分别形成胚性和非胚性愈伤组织，建立体细胞胚胎发生实验系统。应用Native/SDS双向凝胶电泳分析，结果表明，非胚性愈伤组织分化培养前后均存在一种分子量为45kD的非胚性蛋白质N1，另一种非胚性蛋白质N2（54kD）仅     

克隆植物中国沙棘种群稳定性维持途径的探讨

中国沙棘属于阳性树种,因此有些学者将其视为群落演替过程中的先锋种群,而有些学者的研究表明它在自然状态下更新良好。近年来的研究进一步证明,中国沙棘能够依靠克隆生长所赋予生理整合和觅养行为等特性提高环境资源的利用效率以及自身的繁殖和生存有效性,通过林窗更新和林缘扩散等途径维持种群的稳定性和持久性。     

安徽省茶树细菌性梢枯病病原鉴定

2017年-2018年在安徽省庐江、东至县茶园种植区发现一种茶树新病害——梢枯病,发病症状表现为顶芽枯死,嫩叶叶柄变褐,叶片枯萎.为明确庐江、东至县茶树梢枯病的病原菌,采用平板划线法和稀释涂布平板法分离病原,按照柯赫氏法则对病原细菌进行致病性测定,并利用细菌的表型特征和分子生物学技术确定病原菌的分类地位.结果表明,从茶...     

魔芋软腐病病原菌TaqMan荧光探针PCR技术的建立及应用

为实现对田间土壤软腐病病原菌的定量检测,基于魔芋软腐病优势病原菌胡萝卜软腐果胶杆菌胡萝卜亚种Pectobacterium carotovorum subsp. carotovorum的FyuA基因序列,设计特异性引物PCC1/PCC2/PCC3,建立TaqMan荧光探针实时荧光定量PCR技术,并对魔芋根系土壤中软腐病病原菌进行动态监测。结果显示:基于FyuA基因序列设计的引物特异性好,仅能特异性检出胡萝卜软腐果胶杆菌胡萝卜亚种;当模拟带菌土壤中病原菌浓度低至1.88 CFU/g时也能检出,灵敏度高;发病魔芋根际土壤中软腐病病原菌检出率为100.00%,病原菌DNA浓度最高达到了7.52×10~7ng/μL,健康魔芋根际土壤中也存在病原菌,检出率为40.00%;不同种植模式中,林下魔芋土壤中软腐病病原菌数量较少;连作时间与病原菌数量、病情指数存在正相关关系,连作时间越长,病原菌积累越多,魔芋病情指数也越高,魔芋连作4年土壤中病原菌DNA浓度最高达到4.03×10~4ng/μL;对魔芋土壤软腐病病原菌进行全年监测,病原菌数量随着月份增长逐渐上升,在8—10月达到峰值543.20 ng/μL后下降,病原菌数量与魔芋病情指数变化规律一致,但田间魔芋软腐病的发生相对滞后。表明建立的TaqMan荧光探针实时荧光定量PCR技术可用于田间魔芋软腐病的监测。     

Suppurative meningoencephalitis and perineuritis caused by Streptococcus gallolyticus in a Japanese Black calf

A 179-day-old calf, which was weak and stunted, showed neurological signs and was euthanized. Postmortem examination revealed extensive and severe cloudy area in the meninges, and pleural pneumonia. Gram-positive cocci were isolated from systemic organs. Biochemical and 16S rRNA gene sequence analyses identified the isolate as Streptococcus gallolyticus, and its subspecies was suggested to be gallolyticus (SGG). The isolate was classified as a novel sequence type (ST115) by the multilocus sequence typing scheme for SGG and showed susceptibility to penicillin, ampicillin, amoxicillin, florfenicol, sulfamethoxazole-trimethoprim, and chloramphenicol. Histopathologically, suppurative meningoencephalitis and perineuritis were detected. As SGG has been isolated solely from a cow with mastitis in Japan, this is the first SGG infection in a calf with suppurative meningoencephalitis and perineuritis in this country.