巴西蕉诱导的香蕉枯萎病菌1号和4号小种致病相关基因表达分析

目前对于香蕉枯萎病菌的致病分子机制尚不十分清楚。为了阐明枯萎病菌的致病分子机制,从香蕉枯萎病菌1号(Foc1)和4号小种(Foc4)的比较蛋白质组学分析发现的表达量差异较大的蛋白中,选取了9个致病相关蛋白或潜在的致病基因,利用荧光定量PCR方法进行基因表达谱分析。结果显示：与对照相比,巴西蕉处理的Foc4中,上调表达的基因有：酰胺转移酶基因（amidotransferase）、线粒体过氧化物还原酶基因（mitochondrial peroxiredoxin）、几丁质酶基因（chitinnase 1）、羧肽酶基因（carboxypeptidase cpds）,差异表达不明显的有腺苷激酶基因（adenosine kinase）、NADP-依赖型甘油脱氢酶基因（NADP-dependent glycerol dehydrogenase）、磷酸甘油酸激酶基因（phosphoglycerate kinase）、谷胱甘肽还原酶基因（glutathione reductase）、酰胺酶基因（amidase family protein）。Foc1中,与对照相比,上调表达的基因有：腺苷激酶基因、NADP-依赖型甘油脱氢酶基因,下调表达的基因有：酰胺转移酶基因、羧肽酶基因。综合分析显示,酰胺转移酶、过氧化物酶、几丁质酶、羧肽酶基因可能在Foc4的致病作用中起作用。     

小麦条锈菌毒性变异与DNA多态性的相关性

为了解小麦条锈茵毒性和DNA多态性之间的相关性,为SSR标记技术在条锈茵群体遗传分析中的应用提供理论依据,对90个小麦条锈茵茵系进行了毒性和DNA多态性分析.毒性分析发现17种致病类型或生理小种,SSR分子标记分析发现75个基因型,DNA指纹的多态性远比毒性的多态性丰富.不同小种有相同或相近的DNA指纹,同一小种可能有不同的DNA指纹.毒性特征和DNA多态性之间并不存在相关性,SSR标记技术可用于小麦条锈茵群体遗传分析.     

海链藻对氮磷需求量的研究

本实验初步研究了海链藻对氮磷的需求，研究结果表明：以等摩尔氮的NH4Cl、NaNO，和NFLNO3作为氮源时，选择NH4NO3为氮源可以获得较快的生长率并维持较长时间的指数生长期；氮源浓度的最适范围在0．54-1．08mmol／L之间。而2．16mmol／L以上的高浓度NH4NO3则对海链藻的生长有一定的抑制作用；在不同磷浓度(0．015-0．12mmol／L)的条件下，海链藻保持大致相同的生长速率。     

Active metabolism in larval and juvenile fish: ontogenetic changes,effect of water temperature and fasting

Oxygen consumption, ammonia excretion and fish swimming speed were measured in fish induced to swim by optomotor reaction in a circular metabolism chamber. The relationship between the swimming speed and fish metabolism described by exponential equations allowed the extrapolation to the standard metabolism, i.e. at zero swimming speed. The partitioning of the catabolised protein in the energy supply was estimated based on AQ (volume of ammonia/ volume of oxygen) values. Weight specific standard metabolism, as expressed by the ammonia excretion rate, decreased by one order of magnitude in coregonids as the fish grew from 20 to 780 mg body weight. The slope of the relationship between oxygen uptake and swimming speed decreased in coregonid ontogenesis. In salmon, after 12 days of fasting 28% of energy used was derived from protein, whilst coregonid juveniles utilized mostly lipid. Active swimming in fasted juveniles of coregonid, as well as in salmon, led to the accelerated utilization of protein as a source of energy, based on AQ coefficients. In juveniles acclimated to a range of water temperatures from 14 to 26°C, the changes in standard or active metabolic rate (expressed as oxygen uptake or ammonia excretion) were described by Q₁₀ coefficients. They were generally higher for the ammonia excretion rate than for the oxygen uptake rate and for active metabolism than for standard metabolism. Utilization of protein as energy for swimming differed significantly between the species, being in general one order of magnitude higher in coregonids than in salmon. The use of protein for swimming activity tended to decrease during coregonid ontogenesis.     

青岛陆源排污口邻近海域异养细菌的组成与分布

对青岛近海度假区、港口区、养殖区、工业区4类排污口邻近海域异养细菌的组成与分布进行了调查研究,采用海洋异养细菌平板涂布培养法分离细菌,基于16S rDNA的扩增性DNA限制性酶切片段分析(ARDRA)进行聚类筛选并测序鉴定。结果显示,青岛排污口邻近海域可异养培养的菌株分布于变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)和拟杆菌门(Bacteroidetes)4个细菌类群,变形菌门细菌数量占总测序数量的68%,其中γ-变形菌纲的数量在变形菌门中占88%;不同海域中细菌组成与分布有所不同,放线菌门和拟杆菌门的细菌种类较少且各海域分布有所不同,但γ-变形菌纲的弧菌属细菌(Vibrio sp.)在4类海域中均被发现,占总检测量的18.54%,其中溶藻胶弧菌(Vibrio alginolyticus)占弧菌总量的25%。不同海域也检测到V.parahaemolyticus、V.harveyi、V.campbellii、V.parahaemolyticus等水产养殖业的潜在致病菌。根据16S rDNA系统进化关系和细菌门类聚类分析得到的结论推断,工业区与养殖区海域的细菌组成和分布相似度较高,推断各海域的细菌组成与排污口类型有一定相关性。     

中国北方野生雄绒螯蟹成蟹可食率和生化成分分析

比较了2017年10月由我国绥芬河、图们江和辽河采集的质量为80～160 g的野生雄绒螯蟹成蟹的组织系数、总可食率、可食组织中一般化学组成及脂肪酸组成.试验结果显示:(1)3个种群雄体性腺指数、肝胰腺指数和出肉率差异显著,但3个种群总可食率无显著差异(P>0.05).(2)就性腺而言,图们江种群水分含量最高,绥芬河种群...     

一株引起坛紫菜绿斑病病原的分离鉴定及致病性研究

为了明确引起坛紫菜绿斑病的病原,对2012年发生在福建省莆田养殖海区坛紫菜叶状体绿斑病开展了病原的分离鉴定和致病性研究。利用2216E海水培养基平板,从患病藻体分离得到一株优势细菌X5;在实验室条件下将X5进行回接感染实验,在显微镜下观察到坛紫菜叶状体发生组织病理变化,出现绿斑病症状:感染初期出现黄绿色小斑点,病斑逐渐扩大出现空洞,最后导致紫菜叶片流失;用浓度为10⁴~10⁸ cfu/mL的X5感染坛紫菜时,在7 d内引起紫菜出现10%~100%病斑面积,这些结果表明X5为坛紫菜绿斑病的病原。利用生理生化和多基因序列分析方法对X5进行鉴定,结果显示该菌为革兰氏阴性菌,大小为0.6 μm×0.4 μm~1.0 μm×0.4 μm,无鞭毛,在温度4~42℃、盐度50~150、pH6~10范围内生长,最适生长温度为16℃,最适生长盐度为50,最适pH为7,对甲硝唑、林可霉素和青霉素耐药,对25种抗生素敏感,Biolog和API ID-32E细菌鉴定系统的结果显示X5为弧菌属细菌(Vibriosp.);基于多基因序列(16S rRNA,rpoA,recA,pyrH)构建的系统进化树分析显示,X5与V.casei、V.litoralis、V.rumoiensis聚为一支,进化距离为0.095~0.108,这些结果说明X5为弧菌属的一个新种或是V.casei、V.litoralis、V.rumoiensis之一的一个新亚种。本研究报道了弧菌X5能够引起坛紫菜绿斑病,为紫菜流行病学及疾病防治提供了理论支撑。     

4种单胞藻对卤虫生长和生殖影响的比较研究

以亚心形扁藻、小球藻、湛江等鞭金藻、绿色巴夫藻为饵料,卤虫为投喂对象,建立五个实验组分别进行研究,观察不同饵料对卤虫生长和生殖的影响,结果表明:投喂亚心形扁藻的卤虫生长最快,成活率高,生殖量也最多,其次为绿色巴夫藻组,湛江等鞭金藻的饵料效果最差.混合4种单胞藻投喂的效果也较好.     

Digestibility of the defatted microalgae Nannochloropsis sp. and Desmodesmus sp. when fed to Atlantic salmon,Salmo salar

The aim of the study was to investigate the apparent digestibility coefficient (ADC) of defatted biomass derived from microalgae Nannochloropsis sp. and Desmodesmus sp. when fed to Atlantic salmon postsmolts in seawater. Two experiments, one employing cold‐pelleted and the other employing extruded pellets, were carried out to determine the ADC of dry matter (DM), protein, ash and energy. The test feeds consisted of a fishmeal‐based reference feed and the algal biomass, at a ratio of 70:30, and yttrium oxide as the inert marker. The ADC of DM and protein in fish fed microalgae‐incorporated cold‐pelleted feeds were significantly higher for Nannochloropsis sp. compared with Desmodesmus sp. The Nannochloropsis sp. inclusion in extruded feeds also led to higher ADCs of DM and energy compared with Desmodesmus sp. The extrusion processing significantly increased the ADC of ash in both defatted microalgae biomass, as well as ADCs of DM in Nannochloropsis and protein in Desmodesmus sp. In conclusion, the microalga Nannochloropsis sp. was more digestible than Desmodesmus sp., and extrusion processing can be used as a means to improve digestibility of certain nutrients.     

鲢鳙占优势的千岛湖浮游动物群落结构特征及其与环境因子的相关性

为了解以鲢鳙占优势的千岛湖中浮游动物群落结构特征以及与水温、溶解氧等环境因子的关系,采用方差分析、典范对应分析等方法,对千岛湖河流区、过渡区、湖泊区3个地区的浮游动物种类、数量以及环境因子的月变化特征进行了调查。结果表明:2007—2008年,共鉴定出浮游动物115种,其中原生动物16种、轮虫51种、枝角类23种、桡足类25种。浮游动物密度在春季(2007年:840.9/L,2008年:850.5/L)形成高峰;生物量在春季(2007年:1.89mg/L,2008年:0.837 mg/L)和秋季(2007年:1.63 mg/L,2008年:0.802 mg/L)形成双高峰;现存量从河流区至湖泊区依次递减。河流区和过渡区的浮游动物密度均于4 m水层达最大值,湖泊区于8 m水层达到最大值。各位点4～12 m水层的大型浮游甲壳动物优势种透明溞、蚤状溞、球状许水蚤等和小型浮游甲壳动物优势种长额象鼻溞、颈沟基合溞、台湾温剑水蚤等的生物量较高。原生动物、桡足类生物量与溶解氧显著正相关;轮虫、枝角类生物量与总氮、硝态氮、浮游植物生物量极显著正相关。典范对应分析(CCA)表明,溶解氧、温度、总氮、总磷、硝态氮是影响浮游动物时空分布的主要因子。透明溞在2—6月份主要受到以浮游植物为食物的上行效应的影响较大,而其他月份主要受水温的影响较大。