植物乳杆菌和肠膜明串珠菌共培养时的选择性计数法

基于植物乳杆菌ST-Ⅲ和肠膜明串珠菌BD1710在添加不同碳源的MRS固体培养基上的菌落形态差异,建立2株菌共培养时的2种选择性计数方法,分别为差值法和色差法。结果表明:2种方法均能够满足选择性计数的要求,且差值法中植物乳杆菌ST-Ⅲ和肠膜明串珠菌BD1710的平均检出率(97.2％和96.4％)均略高于色差法(95.4％和94.0％),因此差值法更适用于对精确度要求较高时数据的采集,而色差法具有操作简便和成本较低的优势,更适用于工厂进行快捷的活菌数量检测。     

浙江荚蒾属植物小志

在编写“浙江植物志”的过程中,作者最近从事浙江产的荚蒾属(Viburnum Linn.)的研究。本文包括23种,1变种及2变型,分隶于:(1)锥序组Sect,Thyrsosma (Rafin.)Rehd.—3种,(2)荚蒾组Sect.Viburnum—4种及1变型,(3)合轴组Sect.Pseudotinus C.B.Clarke—1种,(4)球核组Sect.Tinus(Borkh.)Maxim.—种,(5)蝶花组Sect.Pseudopulus(Dipp.)Rehd.—1种及1变型,(6)齿叶组Sect.Odontotinus Rehd.—12种及1变种,以及(7)裂叶组Sect.Opulus A.DC.—1种。其中尚有归并为同物异名者1种及1个新组合的亚种。 作为分类学研究成果,本文提供了对主要器官及附属物的特征,分组及分种的检索表,对每一分类群的地理分布、生态条件等作了系统的论述和列举。 本文中所被研究的大量标本均藏于杭州植物园标本室、杭州大学生物系标本室及浙江博物馆标本室。     

南美白对虾肠道细菌菌群分析

对健康养殖南美白对虾胃、肝胰腺、肠道、肌肉中的需氧菌群进行研究。结果表明:胃、肝胰腺、肠道、肌肉中的异氧细菌总菌数分别为5.3×105~6.5×107cfu/g、6.6×105~5.2×106cfu/g、1.4×108~4.5×109cfu/g和1.0×104~1.1×105cfu/g。对从其肠道中分离出来的111株菌株进行属(科)的鉴定。这些菌株分属于13个属(科),发光杆菌属、弧菌属、气单胞菌属、肠杆菌科、黄单胞菌属、土壤杆菌属、芽孢杆菌属、棒状杆菌属、小球菌属、黄杆菌属、产碱杆菌属、假单胞菌属和色杆菌属,还有一株未鉴定的革兰阳性菌。其中优势菌为发光杆菌属、弧菌属,气单胞菌属、肠杆菌科、黄单胞菌属,次优势菌为土壤杆菌属、芽孢杆菌属、棒状杆菌属、小球菌属。     

速生桉树实验形数的研究

角规测树是简便、可靠的林分蓄积量调查方法,为寻求速生桉树最佳实验形数,文章采用标准行法和角规法调查50个桉树小班的林分蓄积量,通过对比分析表明速生桉树最佳实验形数为0.38。     

关于Fuzzy拓扑空间的可数性

在以往研究提出的Ｆｕｚｚｙ的点概念和邻近构造思想的基础上，构造了Ｆｕｚｚｙ拓人间的禽近性质，并有效地将拓扑空间的基的概念推广到Ｆｕｚｚｙ拓扑空间，给出了Ｆｕｚｚｙ拓人间的（广义）第一可数性公理Ｆ－Ｃ１及（广义）第二可数性公理Ｆ－Ｃ１；讨论了它们之间的与性质。     

Are standard protocols needed for performing weight counts?

The most common way of counting fish is to use subsampling to determine the number of fish/lb. (weight count) and use weight measurements instead of counting individual fish. We compared differences in methods commonly used to determine weight counts. We found that none of the methods differed from each other and the mean weight counts remained close to the true weight count. Number of samples required to achieve accuracy depends on the individual performing the weight count and the size of fish. Efforts should be made to satisfy probability theory assumptions.     

Microbial aspects of atrazine biodegradation in relation to history of soil treatment

Among 15 soils with different cropping practices, seven which had an history of repeated atrazine applications showed accelerated degradation of this herbicide. By contrast, grassland or agricultural soils with no recorded atrazine application, at least for the last three years, had a low degradation potential. No direct relation was found between the rate of atrazine mineralisation and the size of the microbial biomass. In adapted soils, the amounts of extractable residues were lowered and the very high percentages of radioactivity from [ring-¹⁴C]atrazine recovered as [¹⁴C]carbon dioxide demonstrated that N-dealkylation and deamidation were the only processes for micro-organisms to derive carbon and energy for heterotrophic growth. Kinetics of microbial ¹⁴C accumulation revealed that atrazine ring carbon could be incorporated by direct oxidative condensation with structural components of the bacterial or fungal cell whereas side-chain carbon was preferentially used for biosynthesis of new protoplasmic cell material, as confirmed by the high turnover rate of radiolabelled microbial components. From the determination of the Michaelis–Menten parameters, V_m and K_m in the presence of different selective biocides, it was possible to conclude that fungi were probably less active in atrazine degradation than bacteria and that over years the microbial atrazine-degrading community showed an increased efficiency. © 1999 Society of Chemical Industry     

角规测树的进测木蓄积计算方法研究

在森林资源连续清查中,当两期间的保留木株数和材积确定之后,角规测树的保留木生长量和进测木材积是确定的,可以用计算式计算产出,不需要计算多个结果凭经验来确定。     

用遗传算法进行RFD装置优化设计

免维修流体输送装置RFD由压缩空气做动力,通过气液换能驱动被输送液体间歇性出料。该装置不含运动部件,其优化设计是关系到装置高效稳定运行的关键理论。文中分析了传统枚举法和边际效用法在方案搜索中存在的问题,重点讨论了遗传算法在多目标高维优化问题中的应用,通过计算实例比较了3种方法的计算结果,得出遗传算法在本问题求解中的优势。最后,针对流量和扬程需求,采用遗传算法进行了装置的系列化设计,并分析了有关结构参数和运行参数的变化规律,进一步给出了不同密度和粘度下,RFD装置输送流量的换算关系,为RFD装置的工业设计打下坚实的基础。     

乳酸菌计数培养基和培养方法的筛选

对保加利亚乳杆菌和嗜热链球菌活菌计数的培养基和培养方法的研究结果表明，采用保加利亚乳杆菌选择性培养基的双层平板法和酸化的MRS培养基的试管法可对保加利亚乳杆菌进行选择性计数；采用MRS培养基的双层平板法和MRS培养基的试管法可对嗜热链球菌进行选择性计数；采用改进的MRS和西MRS培养基的双层平板法和试管法可对保加利亚乳杆菌和嗜热链球菌的活菌总数进行混合计数。