家蚕对马尾松毛虫质型多角体病毒的敏感性

用虫体克隆技术,对马尾松毛虫质型多角体病毒湖南株（DpCPV-HN）进行了分离纯化,鉴定为质型多角体病毒1型。以家蚕春蕾×镇珠杂种F₁代及自交的F₂代4或5日龄幼虫进行毒力测定,以纯化的家蚕质型多角体病毒对F₁代幼虫的毒力测定为对照。结果表明：家蚕品种春蕾×镇珠对家蚕质型多角体病毒敏感,马尾松毛虫质型多角体病毒湖南株能引起其感染发病;马尾松毛虫质型多角体病毒湖南株感染家蚕品种春蕾×镇珠F₁代幼虫和F₂代幼虫28天后的半致死剂量（LD₅₀）分别为885个和18个CPB(质多角体),前者为后者的49倍。马尾松毛虫质型多角体病毒湖南株感染后的家蚕,其结茧率、化蛹率、羽化率、全茧量、茧层量和单蛾产卵数均有所下降,全茧量、茧层量、茧层率和单蛾产卵数与病毒感染剂量之间无显著关联。     

四倍体中华猕猴桃减数分裂及花粉发育的细胞学观察

观察了四倍体中华猕猴桃(2n=4x=116)雄株花粉母细胞减数分裂和花粉发育过程。在减数分裂终变期和中期Ⅰ,绝大部分染色体呈二价体构型,出现少最环状和链状多价体。胞质发育为同时型。成熟花粉粒为两细胞型。     

耐甲氧西林金黄色葡萄球菌的分子流行病学研究

了解我院患者耐甲氧西林金黄色葡萄球菌（MRSA）的分子流行病学特点,为临床抗感染治疗提供依据。收集2007年1月~2008年9月我院分离的耐甲氧西林金黄色葡萄球菌共54株,采用PCR进行SCCmec基因分型、葡萄球菌A蛋白（SPA）分型,并检测杀白细胞毒素（PVL）基因,同时应用脉冲场凝胶电泳（PFGE）进行同源性分析。54株MRSA菌株SCCmec基因分型为SCCmecⅡ型17株,SCCmecⅢ型33株,SCCmecⅣ型2株,SCCmecⅤ型2株;SPA基因分型将28株归属为t030,9株为t002,8株为t037,5株为t570,2株为t437,t163和t796各1株;PVL毒素检测只有2株SCCmecⅣ型菌株阳性;PFGE证实院内MRSA感染主要为2种克隆株传播,同时还有其他型别出现。本院MRSA流行传播的SCCmec基因型主要以Ⅲ型占优势,同时发现有携带PVL毒素的CA-MRSA分离株流行,应引起密切关注。     

刺五加大,小孢子发生和雌,雄配子发育的观察

刺五加Ｅｌｅｕｔｈｅｒｏｃｏｃｃｕｓｓｅｎｔｉｃｏｓｕｓ（ＳｕｐｒｅｔＭａｘｉｎ．）Ｍａｘｉｍ,雄株的小孢子发生和雄配子体发育过程正常,大孢子发生和雌配子体发育过程多不正常,雄花具５个花药,花药４室,药壁发育属双子叶型,腺质绒毡层,绒毡层细胞多具２核。小孢子母细胞经减数分裂形成四面体形四分体,其胞质分裂为同时型。成熟花粉３细胞型,子房下位,５室：每室有上胚珠和下胚珠,上胚珠退化,下胚珠倒生具单珠被     

生物固氮

931349湖非地区快生型大豆根翻菌的质位及结右甚因的初 「,步定位〔中万沈辉…了微生物学通报一1991,18(1)。一2~4 从湖北省潜江县和监利县的4个采集点分离纯化了26株快生型大豆根瘤菌。质拉分离分析结果表明:所测快生型大豆根瘤菌中均有1~3条质拉带,分子是范围在50~3 00Md之间     

产ESBLs大肠埃希菌的AmpC基因型分析

目的 了解深圳市人民医院产超广谱β-内酰胺酶(ESBLs)大肠埃希菌合并产AmpC酶的状况及基因型特点.方法 从近几年深圳市人民医院产ESBLs大肠埃希菌临床菌株中,筛选出对头孢西丁耐药菌株51株,PCR分别扩增菌株的TEM、SHV、CTX-M基因,同时应用多重PCR检测菌株的AmpC酶基因,序列测定PCR阳性产物以确定其基因亚型.结果 51株菌中有49株至少检出一种ESBLs或AmpC基因.单ESBLs基因阳性菌株37株(72.5％),单AmpC基因阳性4株(7.8％),合并ESBLs和AmpC基因阳性的8株(15.6％).共有41株(80.4％)含CTX-M-14基因,4株含CTX-M-15,其他基因型ESBLs较少.2株检出两种ESBLs基因;一株同时检三种ESBLs基因.检出AmpC基因的菌株12株,其中10株为DHA-1型,2株为CMY-2型;其中6株DHA-1型及2株CMY-2型菌同时检出CTX-M-14基因.结论 该院头孢西丁耐药产ESBLs大肠埃希菌中大多数为单产ESBLs菌,主要为CTX-M-14型;少数同时产生ESBLs和AmpC酶,AmpC酶以DHA-1型为最常见.     

昆虫质型多角体病毒的研究进展

质型多角体病毒(Cytoplasmic polyhedrosis virus,CPV)隶属呼肠孤病毒科Reoviridae质型多角体病毒属Cypovirus,通常基因组由10个节段双链RNA构成。RNA分子量为3～27u。根据病毒基因组dsRNA片段在聚丙烯酰胺或琼脂糖凝胶中电泳图谱的差异,目前CPV已被分为19个电泳型。不同于呼肠孤病毒科其它成员,CPV为单层衣壳,而不是常见的双层衣壳结构,衣壳蛋白主要由衣壳蛋白、大突起蛋白及塔式突起蛋白组成。大部分质型多角体病毒引起昆虫慢性疾病,造成寄主死亡或适应性降低。随着RNA病毒基因序列测定技术的成熟,质型多角体病毒的序列测定方面取得较大进展,目前GenBank核苷酸序列数据库中已经公布了家蚕Bombyx mori CPV电泳型1两个株系(H株和I株)、舞毒蛾Lymantria dispar CPV电泳型1、舞毒蛾CPV电泳型14及粉纹夜蛾Trichoplusia ni CPV电泳型全基因组序列,为该病毒的进化与起源的研究提供更多的遗传信息。本文从结构功能、侵染特点、基因组特点及应用前景等方面综述了昆虫质型多角体病毒的研究进展。     

杂交水稻主要农艺性状配合力遗传力分析

选用生产上常用的5个杂交水稻不育胞质与5个高配合力恢复系,采用NCII模式对产量性状、芒、粒形等主要农艺性状的亲本配合力、方差贡献率及遗传力进行分析。结果表明：胞质效应和恢复系效应在所测性状中均达到显著或极显著差异水平,芒长、粒形、单穗重受环境的影响较小;产量和收获指数的非加性遗传作用明显,受环境效应的影响也较大。亲本效应方面,恢复系的效应远大于胞质效应;产量性状JW型（爪哇型）胞质和蜀恢527的一般配合力效应较高,同时JW型胞质和R21属于Ⅰ类亲本;粒形性状G型（冈型）胞质和蜀恢527的一般配合力效应最高,同时均属于Ⅰ类亲本。     

赤■属的胚胎学研究(英)

描述了葫芦科赤爬属植物生活史的主要过程以及胚胎学的重要特征,它们是：腺质绒毡层,胞质分裂同时型,小孢子四分体四面体型和等面体型,花粉粒散发时具两细胞,双珠被,厚珠心,寥型胚囊,珠孔端受精,胚胎发育柳叶菜型。     

大叶铁线莲大小孢子发生及雌雄配子体发育

铁线莲属植物在花部形态和结构方面存在较大差异, 遗传背景相对复杂。因此, 在杂交育种前对其进行胚胎学研究具有重要意义。利用石蜡切片技术对大叶铁线莲(Clematis heracleifolia)大小孢子发生及雌雄配子体发育过程进行研究, 结果显示, 大叶铁线莲具雄株和两性花植株。雄花中, 雄配子体发育偶见败育现象; 而两性花中多数花粉发育异常, 形成功能性雌花。正常发育的两性花中, 雄蕊较雌蕊先发育完全。花药4室, 具腺质绒毡层, 偶见变形绒毡层。胞质分裂为同时型, 以四面体型四分体为主, 偶见左右对称型。成熟花药中, 花药壁由纤维状加厚的表皮及药室内壁构成, 花粉粒为2-细胞型, 近球状, 散沟型。子房1室, 内含少量退化胚珠及1个发育正常的胚珠, 倒生, 单珠被, 薄珠心, 蓼型胚囊, 具线形大孢子四分体及双核反足细胞。大叶铁线莲可能处于相对进化的过渡地位。在杂交育种中, 建议以雄花植株作为父本, 两性花植株仅用作母本; 在两性花花芽大小为0.5-0.8 cm时进行去雄处理。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.