The potential of nonpathogenic Fusarium oxysporum and other biological control organisms for suppressing fusarium wilt of banana

The aim of this study was to evaluate the ability of nonpathogenic F. oxysporum and Trichoderma isolates from suppressive soils in South Africa to suppress fusarium wilt of banana in the glasshouse. Several biological control agents and commercial biological control products were included in the study. The isolates were first screened in vitro on potato dextrose agar. In glasshouse evaluations, the fungal and bacterial isolates were established on banana roots before they were replanted in pathogen-infested soil, while the commercial biocontrol agents were applied as directed by the supplier. Banana plantlets were evaluated for disease development after 7 weeks. In vitro tests showed none of the nonpathogenic isolates suppressed Fusarium oxysporum f.sp. cubense ( Foc ), while slight suppression was observed with the two Trichoderma isolates. Results of the glasshouse evaluations revealed that two of the nonpathogenic F. oxysporum isolates, CAV 255 and CAV 241, reduced fusarium wilt incidence by 87·4 and 75·0%, respectively. The known biological control agent Fo47 did not suppress Foc significantly. Pseudomonas fluorescens strain WCS 417, known for its ability to suppress other fusarium wilt diseases (WCS 417), reduced disease incidence by 87·4%. These isolates should be further evaluated for potential application in the field, independently and in combination.     

Identification of mutations in the para sodium channel of Bemisia tabaci from Crete, associated with resistance to pyrethroids

We investigated the mechanisms of resistance to α-cypermethrin in a Q biotype, highly resistant Bemisia tabaci strain (GRMAL-RP) isolated from Crete. Cytochrome P450-dependent monoxygenase activity with the substrate ethoxycoumarin, and carboxylesterase activity with the substrates α-naphthyl-acetate, β-naphthyl-acetate, and para-nitrophenol acetate were substantially elevated in the GRMAL-RP, compared to the susceptible SUD-S strain, while glutathione-S-transferase activity with the substrate 1-chloro-2,4-dinitrobenzene was not different. The metabolic inhibitors piperonyl butoxide and S,S,S-tributyl phosphorotrithioate synergised cypermethrin toxicity in the GRMAL-RP strain, however, mortality was still lower than that of the susceptible strain, indicating the presence of an additional resistance mechanism. Analysis of the sequence of the IIS4-IIS6 region of the para sodium channel gene of the GRMAL-RP strain revealed two amino acid replacements compared to that of the SUD-S susceptible strain. One is the leucine to isoleucine substitution at position 925 (L925I) previously implicated in B. tabaci pyrethroid resistance and the other is a novel kdr resistant mutation for B. tabaci, a threonine to valine substitution at position 929 (T929V). Genotype analysis showed that the L925I and T929V were present in all GRMAL-RP males tested, at an approximately 1:1 frequency, but never in combination in the same haplotype.     

家蚕EST数据库的应用现状及展望

家蚕是重要的经济昆虫,也是鳞翅目昆虫的主要模式生物。表达序列标签(EST)在家蚕研究中的应用越来越受到关注。本文主要介绍了EST数据库的建立及其在家蚕研究中的应用现状,展望了EST在家蚕中的研究趋势。     

用麦芽根调节水分对啤酒糟混贮品质的影响

将啤酒糟和麦芽根按不同比例袋装混贮,分别在30、60、90、120 d开袋取样进行感官评定,pH值、氨态氮、干物质、粗蛋白、中性洗涤纤维及有机酸含量分析。结果表明:混贮时间和水分含量均对混贮效果有显著影响;混贮饲料在混贮前60 d各指标变化范围较大,60 d后变化范围较小,并逐渐趋于稳定状态;混贮饲料以含水量50%的袋装混贮效果最好,其次是60%、40%,70%最差。     

猪传染性胃肠炎病毒S基因核酸疫苗免疫小鼠体液免疫功能变化的研究

本实验对TGEV S基因核酸疫苗免疫后体液免疫功能变化进行了研究,同时比较了两种核酸疫苗单独免疫小鼠后体液免疫应答的变化,证明重组核酸疫苗诱导小鼠产生体液免疫应答。     

Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach

Stapanian MA, Witzel LD, Cook A. Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach.
Ecology of Freshwater Fish 2010: 19: 326–337. Published 2010. This article is a US Government work and is in the public domain in the USA Abstract – World‐wide, many burbot Lota lota (L.) populations have been extirpated or are otherwise in need of conservation measures. By contrast, burbot made a dramatic recovery in Lake Erie during 1993–2001 but declined during 2002–2007, due in part to a sharp decrease in recruitment. We used Akaike’s Information Criterion to evaluate 129 linear regression models that included all combinations of one to seven ecological indices as predictors of burbot recruitment. Two models were substantially supported by the data: (i) the number of days in which water temperatures were within optimal ranges for burbot spawning and development combined with biomass of yearling and older (YAO) yellow perch Perca flavescens (Mitchill); and (ii) biomass of YAO yellow perch. Warmer winter water temperatures and increases in yellow perch biomass were associated with decreases in burbot recruitment. Continued warm winter water temperatures could result in declines in burbot recruitment, particularly in the southern part of the species’ range.     

冯契对毛泽东哲学思想的理性解读

冯契对毛泽东哲学思想的理性解读主要体现在 :充分肯定了毛泽东对中国近代哲学革命的历史总结 ,扬弃了毛泽东的辩证法思想 ,基本上肯定了毛泽东对社会理想的探索 ,坚持了毛泽东的义利观、完善了毛泽东的群己观     

欠发达地区旅游业可持续发展技术路径选择研究

结合欠发达地区旅游业发展特点和经济学竞争优势相关理论认为,欠发达地区旅游业可持续发展通常遵循以下技术路径:即起步阶段充分发挥区域资源的绝对优势或比较优势,赢得起步发展空间;中期阶段充分利用后发优势,加速产业升级,实现跨跃式发展;成熟阶段加强资源整合,培育区域旅游业可持续发展的核心竞争优势。     

一枝蒿制剂对小鼠小肠运动作用研究

用两种一枝蒿制剂对小鼠进行小肠推进实验，以甲基硫酸新斯地明、盐酸吗啡和生理盐水为对照。结果表明：一枝蒿健胃促消化机制主要是促进小肠运动。经方差分析和多重比较，其效果相似于硫酸甲基新斯地明     

大豆新品种晋豆37选育技术分析

晋豆37系山西省农科院小麦研究所以晋豆11为母本,埂84为父本杂交选育而成,在山西省晚熟组大豆区试和生产试验中表现良好。介绍了晋豆37的选育过程、在山西省晚熟组大豆区试和生产试验中的产量表现、品种特征特性,并就选育过程谈了选育技术方面的体会。