Identification and characterization of the Vibrio anguillarum prtV gene encoding a new metalloprotease

We cloned and sequenced a prtV-like gene from Vibrio anguillarum M3 strain. This prtV gene encodes a putative protein of 918 amino acids, and is highly homologous to the V. cholerae prtV gene. We found that a prtV insertion mutant strain displayed lower gelatinase activity on gelatin agar, lower protease activity against azocasein, and lower activity for four glycosidases. This prtV mutant strain also had increased activity for two esterases in its extracellular products, as analyzed by the API ZYM system. In addition, the prtV mutant strain exhibited decreased growth in turbot intestinal mucus and reduced hemolytic activity on turbot erythrocytes. Infection experiments showed that the LD₅₀ of the prtV mutant strain increased by at least 1 log compared to the wild-type in turbot fish. We propose that prtV plays an important role in the pathogenesis of V. anguillarum.     

河南祁雨沟金矿同位素地球化学和矿床成因分析

祁雨沟金矿位于华北克拉通南缘的熊耳地体，是典型的爆破角砾岩型金矿。本文全面总结并深入分析了祁雨沟金矿的同位素地球化学研究资料，以氢-氧-碳同位素体系确定成矿流体由岩浆热液向大气降水热液演化，以碳-硫-铅同位素体系厘定成矿物质主要来自岩浆流体系统，以铅、碳同位素确定熊耳地体南侧的中-新元古代地层是不可缺少的成岩成矿物质来源之一。因此认为：在中生代华北与扬子板块碰撞造山过程中，熊耳地体南侧的陆壳板片沿马超营断裂俯冲到熊耳地体之下，通过变质脱水-熔融作用派生了祁雨沟岩浆-流体成矿系统，其成因可由碰撞造山成岩成矿与流体作用模式（即CMF模式）解释。     

论人工岛上建筑物的勘察

随着围海造地,填海建岛项目的不断增多,在人工岛上进行建筑物勘察也逐渐成为一个新的领域。人工岛上的建筑物勘察和陆地上的勘察还是有所不同的,通过工程实践总结一些经验,为越来越多的岛上勘察类似项目起到借鉴作用。     

河南祁雨沟金矿流体包裹体及矿床成因类型研究

河南祁雨沟金矿位于华北克拉通南缘的熊耳地体．产于燕山期火山隐爆角砾岩筒内。流体包裹体研究表明．祁雨沟金矿不同成矿阶段的石英中的流体包裹体有3种类型：水溶液包裹体、含子矿物包裹体和含CO2包裹体。成矿早期流体为高温（〉350℃）、高盐度（〉30wt％NaCl．eqv）、高氧逸度、富CO2的岩浆流体,经流体减压沸腾、挥发分逸失、氧逸度降低、温度降低演化为导致大量金属硫化物及金沉淀的还原性流体．再经大气降水的混入和降温等过程．演化为晚阶段低温、低盐度的大气降水热液。祁雨沟金矿的地质和成矿流体特征指示其应为爆破角砾岩型．而非浅成低温热液型．     

小波变分法遥感影像薄云去除

针对遥感影像薄云去除过程中丢失影像细节及薄云去除不彻底等问题,本文提出了一种基于小波变分法去除遥感影像薄云的方法.首先,对含薄云的遥感影像进行小波分解,可以使低层低频分量中的局部瞬变信号(不具备低秩性的有用信息)被分解到高频分量中;其次,考虑第五层低频分量中有用信息具有低秩性及薄云具有稀疏性特点,建立一种能够从第五层低...     

Construction and characterization of a fosmid library for pathogenic bacterium <Emphasis Type="Italic">Vibrio anguillarum</Emphasis>

Vibrio anguillarum is a common bacterial pathogen in fish.However,little is known about its pathogenic mechanism,in part,because the entire genome has not been completely sequenced.We constructed a fosmid library for V.anguillarum containing 960 clones with an average insert size of 37.7 kb and 8.6-fold genome coverage.We characterized the library by end-sequencing 50 randomly selected clones.This generated 93 sequences with a total length of 57 485 bp covering 1.4% of the whole genome.Of these sequences,58...     

浅谈贺大庄水源地岩溶水分布规律与施工布井

贺大庄供水水源地主要抽取碳酸盐岩岩溶水,可溶岩层裸露--半裸露,含水岩组为上古生界老李山组(Pz21)大理岩,岩溶形态强烈发育,以溶隙、溶孔为主,局部密集成带,宽20～40 cm.岩溶水直接接受大气降水的入渗补给,沿云阳--维摩寺断裂带由北西向南东运移,形成宽2.5～5.0 km,最大宽度7 km的强迳流带,是一个独立...     

Identification and characterization of the Vibrio anguillarum prtV gene encoding a new metalloprotease

We cloned and sequenced a prtV-like gene from Vibrio anguillarum M3 strain.This prtV gene encodes a putative protein of 918 amino acids,and is highly homologous to the V.cholerae prtV gene.We found that a prtV insertion mutant strain displayed lower gelatinase activity on gelatin agar,lower protease activity against azocasein,and lower activity for four glycosidases.This prtV mutant strain also had increased activity for two esterases in its extracellular products,as analyzed by the API ZYM system.In additi...     

螺杆钻具在煤系地层地热井工程中的应用

在对煤系地层特点和螺杆钻具优势分析的基础上,介绍了采用螺杆钻具+PDC钻头或三牙轮钻头在煤系地层地热井工程的应用情况,并对其应用效果及经济效益进行了分析。结果表明,在煤系地热井工程中采用螺杆钻具+PDC钻头或三牙轮钻头的钻探工艺,可以提高机械钻速、缩短钻井周期,对降低钻井成本具有显著的现实意义。