海洋细菌AiL3菌株防治香蕉枯萎病研究

采用室内盆栽和大田小区试验对海洋细菌AiL3菌株防治香蕉枯萎病作用及对香蕉的促生效果进行测定.结果表明:菌株处理后盆栽试验和大田试验中的香蕉苗叶片数、株高、光合速率和蒸腾速率等均明显高于对照;AiL3菌株盆栽试验处理6个月后对香蕉枯萎病的防治效果达100％,大田小区试验菌株处理8个月后对香蕉枯萎病的防治效果分别为72.71％和46.32％.表明AiL3菌株对香蕉植株有一定的防病促生作用.     

茶园土壤高活性氨化菌的筛选鉴定及特性研究

经过菌株富集培养、分离纯化等一系列步骤,从山东茶园土壤中分离出33株氨化细菌菌株。经过活性比较和菌株分类,从中选出3株不同种属的高活性菌株。通过对其进行形态特征、生理生化指标的测定及16 S rDNA测序,初步鉴定菌株SNT3属于芽孢杆菌属,菌株SNT6属于微小杆菌属,菌株SNT33属于不动杆菌属。同时对菌株的生长环境以及氨化活性进行了初步研究。结果表明:菌株SNT3、SNT6和SNT33适宜的pH依次为5～8.5、6～8.5、5～7;3株菌株的最适宜生长温度为35℃;在氨化能力方面,菌株SNT3高于菌株SNT6、SNT33。     

大豆根系土壤中微生物的初步研究

大豆根系土壤中，细菌数量最多，其次为放线菌，真菌数量最少，其群体数量受土壤pH值影响较大。大豆根际土壤微生物总数明显高于大豆根外土壤微生物总数，土壤湿度对微生物习性及繁殖有决定性效应。     

多重PCR检测耐除草剂转基因作物

为建立耐除草剂转基因作物的高通量检测方法,本试验以目前生产上广泛应用的5种除草剂抗性基因dmo、pat、CP4EPSPS、bar和aad1为靶标进行多重PCR(MPCR)研究。通过引物适用性测试、反应体系中的不同引物浓度和反应程序中的退火温度测试、灵敏度和特异性验证等,建立了能同时检测5种除草剂抗性基因的MPCR检测方法。结果表明,当dmo、pat、CP4EPSPS、bar、aad1基因的检测引物终浓度分别为0.2、0.2、0.3、0.4、0.2μmol·L^-1,退火温度为63℃时5种靶标扩增效果较好,且特异性条带清晰且均一。此外,MPCR检测方法具有较好的特异性,对每种靶标的检测灵敏度均可达到0.1%。适用性测试结果显示,MPCR检测方法可对含有5种除草剂抗性基因的多种转基因作物的单个品系或多个品系混合物进行筛选检测。无假阳性和假阴性结果表明,MPCR检测方法对实际样品具有很好的适用性。本试验结果为筛选高效耐除草剂转基因作物检测技术提供了一定的理论依据。     

耐冷菌的适冷分子机制及在污水处理中的应用

指出了低温是影响冬季寒冷地区生活污水处理效果的一个主要原因,在低温环境下,活性污泥中大多数中温菌的生长活性受到抑制,只有少数的耐冷菌可以存活下来并保持一定的活性。简要介绍了低温微生物的概念及分类,从细胞膜结构、低温酶、蛋白质合成以及冷休克蛋白等方面对耐冷菌的适冷机制进行分析,最后对耐冷菌在污水处理中的应用现状与发展方向进行了展望。     

一株耐铝甜瓜枯萎病拮抗细菌的分离鉴定及其耐铝特性研究

从甜瓜根际酸性土壤中分离筛选到1株耐铝甜瓜枯萎病拮抗菌，命名为A2。根据表型、生理生化特征和16S rRNA基因序列相似性分析，将其鉴定为Pseudomonas sp.。菌株A2对甜瓜枯萎病病原菌的相对防效为68.3%，且拮抗能力具有遗传稳定性。相比AlCl3处理，菌株A2对Al2(SO4)3表现出了更好的耐受性，最高可耐受50mmol/L Al3+。在含有A13+的S-LB培养基中，菌株最适生长温度为30 ℃；培养基初始pH值的降低会加剧A13+对菌株A2的毒害作用。研究结果可为含活性铝的酸性土壤中甜瓜枯萎病的生物防治提供优良菌株资源和理论基础。     

一株致病性粪肠球菌的分离与鉴定

从1羽发病雏鸡中分离到1株溶血性革兰氏阳性球菌。初步分离鉴定后经攻毒试验能够造成小白鼠和雏鸡死亡,具有致病性。药敏试验表明,该菌对多种药物均表现耐药性,仅对庆大霉素、青霉素、氧氟沙星敏感。通过BLAST软件分析该菌株的16S rRNA序列,确定该致病性细菌为粪肠球菌。     

Epizootics of Streptococcus agalactiae infection in captive rays from Queensland,Australia

The aim of this study was to describe two epizootics of high mortalities from infection with Streptococcus agalactiae, occurring in captive rays held in a marine display aquarium in south‐east Queensland, Australia, in 2009 and 2010. Five different species of rays were affected, including mangrove whiprays (Himantura granulata), estuary rays (Dasyatis fluviorum), eastern shovelnose rays (Aptychotrema rostrata), white‐spotted eagle rays (Aetobatus narinari) and blue‐spotted mask rays (Neotrygon kuhlii). This report describes the history of both epizootics including collection, quarantine and husbandry of rays, the disease epizootics, clinico‐pathological features of the disease, antimicrobial therapy, autogenous vaccine production, and laboratory studies including clinical and histopathology, bacteriology, PCR, molecular serotyping and sequencing of the bacterium S. agalactiae.     

Preliminary study to evaluate the effects of dietary bile acids on growth performance and lipid metabolism of juvenile genetically improved farmed tilapia (Oreochromis niloticus) fed plant ingredient‐based diets

A 9‐week feeding experiment was conducted to investigate the effects of dietary bile acids (BAs) on juvenile genetically improved farmed tilapia (GIFT) (Oreochromis niloticus) based on the evaluations of growth performance and parameters relevant to lipid metabolism. Each of five vegetable protein‐based diets containing BAs at a level of 0, 0.05, 0.15, 0.45 or 1.35 g/kg diet was fed to three replicates with 40 fish (8.2 g per fish). The results showed that weight gain (WG) increased significantly with the increase in BAs from 0 to 0.15 g/kg diet and then decreased significantly at a higher BA supplementation. Dietary BAs significantly reduced the crude lipid content in the whole body, muscle and liver tissue of GIFT. Fish fed diet with 1.35 g BAs/kg diet developed serious nuclear migration and vacuolization in hepatocytes. Gall bladder appeared to contain white solid and has fragile capsules. Dietary BA supplementation had significant effects on serum biochemical indices and activities of lipid metabolism enzymes in liver and intestine. In conclusion, dietary bile acid supplementation (0.15 g/kg) can facilitate the lipid metabolism and therefore promote the growth of tilapia. However, overdosed dietary BAs induced gallstone development, disrupted lipid metabolism and depressed the growth performances of GIFT.