坚强芽孢杆菌(Bacillus firmus)16S—23S rDNA 间区的克隆及多态性分析

采用16S和23SrDNA保守区设计的引物对两株坚强芽孢杆菌(Bacillus firmus)16S—23SrDNA间区(Intergenic spacer region,ISR)进行了PCR扩增,并克隆到pMD18-T载体上进行测序;利用生物信息学进行了16S—23SrDNA间区序列及其内所含tRNA基因的分析。2株坚强芽孢杆菌共得到11条16S—23SrDNA间区特征区带(包括300、400、500和600bp等)序列,ISR类型包括ISR0、ISRG、ISRIA和ISRGLV四种,其中ISR0、ISRG和ISRIA可能在坚强芽孢杆菌中普遍存在。相同类型的ISR序列具有较高的相似性(达52.2%—100.0%),而不同类型的ISR序列间差异较大。此外,ISR序列在靠近16S和23S区域存在不同长度的保守区域,可能成为针对坚强芽孢杆菌特异性检测的引物和探针的靶区,这也为坚强芽孢杆菌新的检测方法的建立奠定了基础。坚强芽孢杆菌的16S—23SrDNA间区序列及其多态性分析均为首次报道。     

4株对虾肠道益生菌的筛选及鉴定

采用体外拮抗试验的方法,先从不同生长阶段的对虾肠道中分离的96株细菌中筛选出4株对病原菌（鳗弧菌、副溶血弧菌、哈维氏弧菌）有拮抗作用的细菌;进一步通过固体扩散法和液体混合法确定LV060806、LV060808的产物对鳗弧菌有明显抑制作用,Lv060806、LV060815的产物对副溶血弧菌有明显抑制作用,LV060810、LV060815的产物对哈维氏弧菌有明显抑制作用。溶血试验证实这些菌株不产生溶血素,不具有潜在的致病性;动物安全性实验证实菌株浓度在10^6 cfu／ml以下对实验对虾无明显的毒害作用。随后测定了其16S rRNA基因序列,分析了相关细菌相应序列的同源性,构建了系统发生树,结合菌株表型特征和生理生化特性最终鉴定结果为：LV060806、LV060808为Vibrio natriegens;LV060810、LV060815为V.alginolyticus。     

常见水产药物对海洋弧菌的杀灭作用

当前市场上的水产药物种类多、销量大，但究其药效及质量则参差不齐。本文从水产药物对养殖水体中细菌含量的影响，及水产药物对致病海洋弧菌的药物敏感性两个方面，评价了１５种常见的水产药物的药效。ｌ材料与方法１．１药物来源１５种实验药物均由生产厂家提供。１．２实验菌株副溶血弧菌、溶藻胶弧菌购自北京微生物研究所，坎贝氏弧菌由青岛海洋大学生物系提供。１．３培养基细菌培养基为蛋白胨５ｇ，酵母膏１ｇ，磷酸高铁０．１ｇ，琼脂２０ｇ，陈海水１０００ｍｌ（ｐＨ７．６，１０５ｋｐａ灭菌２０ｍｉｎ）。弧菌培养基购自上海生物…     

甘肃黑方台罗家坡滑坡演化过程及运动机制分析

2015年4月29日7时50分,甘肃省永靖县黑方台发生了大规模的滑坡,滑坡体积达1.27×106 m3,摧毁了14户民房和3家工厂,造成直接经济损失5 460万元。在对灾害现场进行大量地质调查的基础上,结合遥感、三维激光扫描等综合调查手段和现场视频监测资料,对罗家坡滑坡演化滑动特征进行了详细描述,对滑坡高速远程机制进行了解析。研究结果表明：罗家坡滑坡从时间线上先后经过5个阶段5种滑动形态,分别是黄土错落-碎屑流、黄土泥岩-碎屑流、黄土-碎屑流、黄土泥流和黄土错落滑动阶段。滑坡运动模式可分为块体碎屑流和黄土泥流两种类型,其中块体-碎屑流高速远程形成机制与先期滑体的“填凹造床效应”和高含水的下垫面土体密切相关。研究结果对于进一步加深对黑方台地区高速远程滑坡的形成机制的认识和风险控制具有积极的指导意义。     

Effects of different enzymatic hydrolysis methods on the bioactivity of peptidoglycan in Litopenaeus vannamei

The effects of different hydrolysis methods on peptidoglycan(PG) were assessed in terms of their impact on the innate immunity and disease resistance of Pacific white shrimp,Litopenaeus vannamei.PG derived from Bifidobacterium thermophilum was prepared in the laboratory and processed with lysozyme and protease under varying conditions to produce several different PG preparations.A standard shrimp feed was mixed with 0.05% PG preparations to produce a number of experimental diets for shrimp.The composition,concentration,and molecular weight ranges of the soluble PG were analyzed.Serum phenoloxidase and acid phosphatase activity in the shrimp were determined on Days 6-31 of the experiment.The protective activity of the PG preparations was evaluated by exposing shrimp to white spot syndrome virus(WSSV).Data on the composition of the PG preparations indicated that preparations hydrolyzed with lysozyme for 72 h had more low-molecular-weight PG than those treated for 24 h,and hydrolysis by protease enhanced efficiency of hydrolysis compared to lysozyme.SDS-PAGE showed changes in the molecular weight of the soluble PG produced by the different hydrolysis methods.Measurements of serum phenoloxidase and acid phosphatase activity levels in the shrimp indicated that the PG preparations processed with enzymes were superior to the preparation which had not undergone hydrolysis in enhancing the activity of the two serum enzymes.In addition,the preparation containing more low-molecular-weight PG enhanced the resistance of the shrimp to WSSV,whereas no increased resistance was observed for preparations containing less low-molecular-weight PG.These findings suggest that the immunity-enhancing activity of PG is related to its molecular weight and that increasing the quantity of low-molecular-weight PG can fortify the effect of immunity enhancement.     

对虾养殖防病新模式初步研究

设计了一个对虾养殖防病新模式，并进行了小规模试验，获得初步成功。在４个３０～４０ｍ＾２的露天水泥池中，各放入３ｃｍ的大苗５００～７００尾（每亩约１００００尾），经９０余天的养殖，对虾成活率８０％左右，个体１０ｃｍ，平均体重８０尾／ｋｇ，饵料系数约１．５。新模式的立足点是防病，特点是设置一蓄水沉淀池，用含氯消毒剂处理养殖用水，配备充气增氧设施，选择优质配饵，合理投喂，使各种水质理化因子及生物因子尽量