Partitioning the spatial and environmental variation of Sclerotinia stem rot on soybean

The variance in survival of Sclerotinia sclerotiorum's sclerotia, carpogenic germination (apothecia) as well as Sclerotinia stem rot (SSR) severity (Disease Severity Index (DSI)) on soybean was partitioned among canopy, soil physico-chemistry and microbiology, cultural practices (2 or 3-y-corn rotation/soybean monoculture and mineral fertilization/urban compost), and spatial matrices in two soils. Partial multiple regression was used to partition the individual SSR variables variance while partial canonical redundancy analysis partitioned the DSI-apothecia and apothecia-survival variance. In clay loam, the sclerotial survival and apothecia variance were mainly explained by the spatial structure of soil physico-chemistry while the DSI did not share this spatial structure and was largely explained by the effects of 3-y-corn rotation on canopy and soil, i.e. lower weed biomass, enhanced soybean yield and fewer apothecia were correlated with disease suppressiveness. In sandy loam, the DSI variance was mostly explained by the spatial structure of canopy and physico-chemistry. Disease suppressiveness, by the interaction of 3-y-corn rotation with urban compost, was largely explained by the enhancement of soil properties, i.e. higher aggregate stability, microbial activity and soil solution concentration in exchangeable ions correlated negatively with carpogenic germination. Partitioning the SSR variance among four matrices of spatial and environmental factors allowed for the first time to interpret and quantify the variance of disease development explained by cultural practices in interaction with the main characteristics of this agroecosystem.     

东海海洋有抗菌活性细菌的筛选及系统发育分析

为了筛选开发新的抗生素,从海水、海泥以及刺鲳、鳗鱼、黄鱼、安康鱼、鲽鱼、马头鱼的鳃和胃肠道中分离得到195株海洋细菌,以金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、黑曲霉和啤酒酵母作为指示菌,用滤纸片法定性测定它们的抗菌活性,筛选到抗菌活性物质产生菌22株.对其中6个抗菌活性较强的菌株进行16S rDNA序列分析,结果显示,它们分别是克氏菌属的Kocuria rhizophila、葡萄球菌属的Staphylococcus saprophyticus、芽孢杆菌属的Bacillus sphaericus和Bacillus thuringiensis、冷杆菌属的Psychrobacter faecalis和变形菌属的Proteus penneri.系统发育分析表明这6个菌株归于3个类群:1个为高(G C)%的革兰阳性菌;3个为低(G C)%的革兰阳性菌;另2个为γ-变形菌.     

Dietary probiotic supplementation in growth and health of live-bearing ornamental fishes

Bacillus subtilis, a probiont isolated from the intestine of Cirrhinus mrigala (Hamilton), was incorporated in fish feed at four different concentrations (5 × 10⁸, 5 × 10⁷, 5 × 10⁶ and 5 × 10⁵ cells g^?1) and fed to Poecilia reticulata (Peters), Poecilia sphenops (Valenciennes), Xiphophorus helleri (Heckel) and Xiphophorus maculatus (Gunther) for a period of 90 days. The growth parameters, proximate composition of whole body, digestive enzymes and gut microbiology were monitored at regular monthly intervals. The increments in length and weight and the survival were significantly higher (P < 0.05) and the values of food conversions were significantly lower (P < 0.05) in fishes fed the probiotic feeds. The administration of B. subtilis in diet resulted in an increase (P > 0.05) in body ash and protein content and in the specific activity of protease and amylase in the digestive tract of all the fishes. The counts of total heterotrophs, motile aeromonads, presumptive pseudomonads and total coliforms were significantly lower (P < 0.05) in the gut of the probiotic fed fishes. Bacillus subtilis persisted in the fish intestine and in the feed in high numbers during the feeding period. The high survival and low infectivity recorded in the probiotic feed fed fishes when challenged by immersion assay with the pathogenic Aeromonas hydrophila demonstrate that the probiotic strain confers disease resistance in live‐bearing ornamental fishes. A probiotic concentration of 10⁶ to 10⁸ cells g^?1 is adequate for improved growth performance and survival and for healthy gut microenvironment and use of higher concentration of the probiont did not always lead to significantly better results.     

分离纯化低聚异麦芽糖的酵母菌菌株筛选

利用酵母菌对不同碳源消耗能力和消耗速度不同的原理，对酵母菌进行筛选试验，选出一株只利用葡萄糖，麦芽糖而不利用异麦芽糖，潘糖，异麦芽三糖等分枝低聚糖的优良酵母菌10号，并对该菌的特性进行了研究。利用10号菌种发酵低纯度的低聚异麦芽糖溶液，可使其纯度达到95%以上。     

高职“食品微生物及检测”课程思政的探索与实践

针对高职院校农产品加工与质量检测专业的“食品微生物及检测”课程,积极探索课程思政建设,梳理设置课程思政目标、精心设计课程思政与专业教学内容衔接点。经过两年的课程思政教学实践,总结创新多种教学方法,建立融合课程思政的专业课程评价与考核体系。实践证明,学生的思政意识显著增强,成绩明显提高,取得了较好的教学效果。      

尖峰岭不同树种枯落物分解过程中微生物动态

为探索微生物在森林枯落物分解中的作用及其在不同气温条件下的变化规律,采用枯落物袋法,研究海南岛尖峰岭热带常绿季雨林枯落物(青梅Vitica mangachapoi,木荷Schimasuperba和混合枯落物)中细菌、真菌和放线菌三大微生物数量的季节变化。结果表明:混合枯落物和木荷枯落物中细菌数量最多,放线菌次之,真菌最少;青梅枯落物中细菌数量最多,真菌次之,放线菌最少。3种枯落物中微生物总数是混合枯落物中最多,木荷次之,青梅最少。同一微生物类群在枯落物中的数量有明显的季节变化,不同类群季节变化规律不尽相同,但基本只有1个峰值。表2参9     

预测微生物学及其在粮食储藏中的应用

储粮中微生物的活动会引发粮食品质劣变,利用预测微生物学的研究方法,通过总结不同温度、湿度条件下微生物活动的变化规律,建立回归线性方程作为预测模型,可随时了解粮食中微生物的活动状况,确保储粮的品质和储藏安全.     

孵化厂微生物学监测

介绍了孵化厂微生物监测的几种技术,包括绒毛取样、空气取样,表面取样和蛋壳表面监测技术,详述了各个方法的步骤及评估标准,并对这些方法的优缺点和可行性进行了比较分析。     

Microbiological controls across the productive cycle of Dicentrarchus labrax L. and Sparus aurata L.: a study from the environment to the final product

The microbiological quality of water, sediments and seafood products of three Sicilian marine fish farms (Castellammare Gulf, Capo d'Orlando and Porto Palo) was investigated in order to draw a complete picture of the health conditions from the start (environment) to the end (seafood product) of the productive cycle. Before the beginning of fish farming, low concentrations of faecal contamination indicators (faecal coliforms, Escherichia coli, enterococci) were found in the water of each examined area. Due to the enhanced organic load released from cages, the set‐up of fish farming significantly altered the distribution of faecal indicators and sometimes that of halophilic vibrios in the pelagic compartment. Significant differences in the density of heterotrophic bacteria were sometimes recorded at the sediment level. Despite this increase in microbial abundance, the microbiological conditions remained acceptable for the productive process. Pathogens (Salmonella spp., Vibrio parahaemolyticus, Listeria monocytogenes, Staphylococcus aureus) were mostly absent in seafood products. The study underlines that the achievement of good quality levels in aquaculture strongly depends on the conformity of the rearing environment to qualitative microbiological standards, highlighting the importance of sanitary controls along the different steps of the productive cycle.     

食品微生物测试片标准法和国标法比较研究

分析了食品微生物检测快速测试片法与国标法的差异性。制备适宜的标准菌悬液,使用快速测试片标准法和国标法分别检测微生物,比较分析2种方法的差异性。所得试验数据通过统计学比较,t值均小于t_(0.05(2)),认为测试片标准法和国标法无显著性差异。