桑尺蠖Thelohania类微孢子虫及其对家蚕的传染性研究

从海宁蚕区的桑尺蠖体中分离到Ｔｈｅｌｏｈａｎｉａ类微孢子虫,其孢子形态大小与家蚕微孢子虫Ｎｏｓｅｍａｂｏｍｂｙｃｉｓ相似．在孢子形成期产生多孢子芽膜,孢子形成数为８个．感染寄生于蚕肌肉、气管、生殖腺、脂肪、马氏管等组织细胞,对蚕幼虫的致病性较弱,胚种传染频率较低     

Effect of position and orientation of leaflet explants with respect to plant growth regulators on micropropagation of Zamioculcas zamiifolia Engl. (ZZ)

Micropropagation studies on Zamioculcas zamiifolia Engl. (ZZ) as to the position and orientation of leaflet explants and plant growth regulators were carried out. Explants consisted of leaflet lamina from the basal or apical part of the leaflet with or without petiolule or midrib that were placed vertically into the medium except for the explants with midrib from the basal part of the leaflet that were placed horizontally as well. The explants were cultured on solid Murashige and Skoog medium (MS) with 30 g l⁻¹ sucrose, supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) at 2 or 4 mg l⁻¹ and 6-benzyladenine (BA) at 0 or 4.44 μM in all (four) possible combinations, or with 1-naphteleneacetic acid (NAA) at 0 or 5.38 μM and BA at 0 or 4.44 μM in all (four) possible combinations (establishment medium). The morphogenic response was direct from all types of leaflet explants and varied only with respect to different plant growth regulators of the medium: 2,4-D combined or not with BA formed somatic embryo-like structures; NAA alone produced tubers and roots; BA alone resulted mainly in leaves; NAA combined with BA produced mainly roots. The intensity of the response varied accordingly to the explant type and orientation. Explants with petiolule or midrib from the basal part of the leaflet showed the highest morphogenic response compared to explants without petiolule or midrib or to explants from the apical part of the leaflet, in all the plant growth regulator combinations used. Explants with midrib from the basal part of the leaflet placed vertically into the media showed higher morphogenic response compared to those placed horizontally on the medium surface. With the objective to regenerate plantlets, explants were subcultured on MS with NAA and BA at various concentrations based on the explant response in the establishment medium, taking into consideration the initial explant type. The initial explant type did not affect the response in the subculture. Most plantlets (a tuber with roots and one leaf with one pair of leaflets) were produced by explants with embryo-like structures induced in a medium with only 2,4-D. Explants with tubers induced in a medium with NAA gave plantlets at 65–85% when subcultured in a medium with 4.44 μM BA alone or in combination with 2.69 μM NAA. Explants with leaves induced in a medium with BA and explants with roots induced in a medium with NAA and BA gave plantlets at low percentages (20–40%). The best response was produced by explants with embryo like structures induced in a medium with only 2,4-D which gave plantlets at 100% when subcultured in the medium with 2.69 μM NAA and 2.22 μM BA. Plantlets raised in different treatments were transplanted ex vitro after 22 weeks and exhibited 80–100% survival.     

秦川牛高档牛肉产量的分子标记研究

以 IGFBP- 3基因作为侯选基因 ,对秦川牛群体中 IGFBP- 3位点与秦川牛高档牛肉产量的关系进行了分析。结果发现 ,不同基因型对秦川牛高档牛肉产出率有一定影响 ,AA、AB及 BB型个体的屠宰率、净肉率及西冷、牛柳、眼肉和嫩肩肉的产率逐渐降低 ,但差异不显著 (P>0 .0 5 ) ;AA型个体的眼肌面积大于 BB型个体 (P<0 .0 5 ) ,AB型和 BB型个体胴体脂肪含量高于 AA型个体 (P<0 .0 1)     

“红肉病”文蛤中寄生类立克次体的超微结构与细胞病理学

报道了患“红肉病”文蛤的消化盲囊上皮中所发现的类立克次体以及所引起的受感染细胞的病理学变化。该病原包涵体呈球形或椭球形,有强嗜碱性和嗜酸性两种,电镜下观察到上皮细胞内充满了大量的类立克次体,其形态结构及大小表现了极大的多样性,受感染的细胞具有明显的病理学变化,内质网膨大为潴泡状,核糖体脱落;线粒体溶解或固缩,核膜肿胀,染色质固缩并出现液泡结构,高度感染时,细胞核与大部分的细胞器消失,在上皮细胞中,观察到类立克次体以二分裂和出芽方式进行繁殖。     

Identification and functional characterization of Histone‐like DNA‐binding protein in Nocardia seriolae (NsHLP) involved in cell apoptosis

Nocardia seriolae, a facultative intracellular bacterium, is the main pathogen of fish nocardiosis. Bioinformatic analysis showed that the histone‐like DNA‐binding protein (HLP) gene of N. seriolae (nshlp) encoded a secreted protein and might target the mitochondria in the host cell. To further study the preliminary function of HLP in N. seriolae (NsHLP), the gene cloning, extracellular products identification, subcellular localization, overexpression and apoptosis detection assay were carried out in this study. Mass spectrometry analysis of the extracellular products from N. seriolae showed that NsHLP was a secreted protein. Subcellular localization of HLP‐GFP fusion proteins mainly assembled in the nucleus, which indicated that the NsHLP was co‐located with the nucleus rather than mitochondria in fathead minnow (FHM) cells. Notably, the expression of NsHLP had changed the distribution of mitochondria into lumps in the FHM cell. In addition, apoptotic features were found in the transfected FHM cells by overexpression of NsHLP. Quantitative assays of mitochondrial membrane potential value, caspase‐3 activity and pro‐apoptotic genes mRNA (Bad, Bid and Bax) expression level demonstrated that the cell apoptosis was induced in the transfected FHM cells. All the results presented in this study provided insight on the function of NsHLP, which suggested that it may participate in the cell apoptosis regulation and play an important role in the pathogenesis of N. seriolae.     

草鱼胰岛素样生长因子—I的融合表达、纯化和抗血清制备

采用PCR方法改造已克隆到的草鱼胰岛素样生长因子-I（IGF-I）cDNA。使其成为成熟肽cDNA并亚克隆到pGEX-4T-1载体中,构建草鱼IGF-I融合蛋白表达质粒pGEX-IGF。质粒转化大肠杆菌BL21菌株,该菌株经IPTG诱导可表达分子量约34kD的特异蛋白。在不同的温度条件下分别产生以可溶性的和包涵体形式为主的特异蛋白,经30℃诱导的菌体经溶菌酶消化、超声破碎及高速离心后,裂解液上清经glutathione sepharose亲和层析纯化获得高纯度的GST-IGF。以此纯化的融合蛋白为抗原制备兔抗草鱼IGF-I的抗血清,凝胶双扩散试验显示抗血清效价为1：64,说明表达产物具免疫原性。     

类猪圆环病毒 P1的感染及其分子特征

类猪圆环病毒P1是新发现的一种病原,能引起仔猪出现类似猪断奶后多系统衰竭综合征症状,是目前所知的具有最小基因组的病毒。为了解P1感染范围和基因组分子特征,采用PCR方法扩增P1全基因组,克隆测序后,应用生物信息学进行序列同源性比较及遗传进化分析。结果显示,P1已在我国猪场流行,分离株之间的核苷酸序列同源性为99．1％～100％,可分为2个亚分支;同时免疫组化结果也证实了P1在样品中的分布。     

大豆黄酮对大鼠离体肝脏氮代谢和胰岛素样生长因子1水平的影响

利用大鼠离体肝脏灌流技术以及大鼠原代培养的肝细胞研究了大豆黄酮 (Da)对SD大鼠肝脏氮代谢和IGF 1生成的影响。结果表明 ,Da可使大鼠离体肝脏灌流液中尿素氮浓度下降 ,并有一定的剂量效应和时间效应。在给药后灌流的1,2 ,3和 4h内 ,与对照组相比 ,1× 10 -4mol·L-1的Da使大鼠离体灌流的肝脏产生的尿素氮分别下降了 13 6 4 % ,2 3 18% ,34 0 2 % (P <0 0 1)和 32 91% (P <0 0 1)。 4× 10 -5mol·L-1的Da对大鼠肝脏尿素氮生成影响具有类似但较微弱的效应。Da还可在一定程度上抑制大鼠离体灌流的肝组织中谷丙转氨酶 (GPT)的活性。 1× 10 -5mol·L-1的Da可使3 H 亮氨酸的参入量与对照组相比提高了 2 1 38% (P <0 0 5 )。Da对离体灌流的大鼠肝脏胰岛素样生长因子 1(IGF 1)的水平也有微弱的促进作用。提示Da可通过增加大鼠肝脏氮的储留 ,促进大鼠肝细胞蛋白质的合成以及在一定程度上影响肝脏GPT的活性和IGF 1水平 ,而调节肝脏的氮代谢。