Cloning and analysis of the antagonistic related genes of <Emphasis Type="Italic">Enterobacter cloacae</Emphasis> B8

To understand the antagonistic mechanism of the broad spectrum antagonistic Enterobacter cloacae B8,Tn5 transposon-mediated mutagenesis is performed using suicide plasmid pZJ25. Two mutant strains that lost antagonistic character are isolated. Tagging with kanr gene on Tn5,an antagonistic related DNA fragment, the F fragment, right of the Tn5 insertion site is cloned in a plasmid named pTLF,from one of the mutant strains B8F. The 733 bp F fragment is then sequenced after subcloning. Genomic DNA of the original B8 strain is isolated, digested with Pst I and ligated to Pst I cassette. DNA fragments left and right of the F fragment are amplified from the Pst I cassette library using cassette primer and specific primers designed according to known sequence. 1106 bp sequence left of the F fragment and 664bp sequence right of the F fragment are finally obtained. Bioinformatics analysis shows that the contig assembled from the sequences of the cloned antagonistic related DNA fragments of B8 encodes three ORFs and is homogeneous to admM,admN and admO genes of Pantoea agglomerans andrimid biosynthetic gene cluster (AY192157). The ORF, named anrF gene which encodes a polyketide synthase, knocked out by Tn5 insertion, is a homology of admM and the insertion site of Tn5 is at 214 bp upstream of the stop codon. It is concluded that the anrF gene is a gene related to the antagonistic activity of E. cloacae B8, and speculated that the antagonistic substance produced by B8 is an andrimid.     

山西花椒昆虫群落结构及区划研究

对山西省花椒昆虫群落的结构和区系进行了研究，共调查了168种昆虫，其中害虫115种，占68％，分属于8目47科．重要的种类是天牛Cerambyeidae，蚜虫Aphididae，蚧壳虫Coccoidae和花椒桔啮跳甲Podugricomela shirahatai等主要害虫，天敌昆虫53种，占32％，分属于7目17科，其数量较多，能对害虫起控制作用的种类是瓢虫Coccinellidae，食蚜蝇Syrphidae，草蛉Chrysopidae和螳螂Mantidae，根据害虫为害部位和为害方式的不同，分为枝杆、花器芽叶及幼果、吸汁性、腐生性和地下害虫5个类群．依照山西省农业区划资料．将全省划分为滹沱河岩岸、太行山中段、晋南阶台地、吕梁晋中4个花椒栽培区．此外，还分析了各生态区的主要栽培品种和主要害虫与天敌昆虫群落的结构。     

广东省乐昌市虫霉目真菌调查

虫霉目真菌包含有重要的昆虫病原真菌,在害虫生物防治中具有很高的开发利用价值,倍受关注.对广东省乐昌市人工和自然生态系统中虫霉目真菌历经3年的调查,记录了虫霉目真菌3属3种,分别为蝗噬虫霉、蝇虫霉和飞虱虫疠霉.     

甘肃森林昆虫生态地理亚省级区划探讨 Ⅲ.各亚省级区划内森林主要害虫名录及主要分布地(下)

据1981—1982年全省森林病虫害普查,甘肃的森林害虫共计664种,隶属于8目98科。本文据笔者二十多年收集的资料和《甘肃省林木病虫普查成果汇编》[2],将森林主要害虫三百多种,按五个亚省级区划[1],分别以学名、中名、主要分布地,列表陈述,以供有关高校教学、科研及林业科技人员参考。本文(下)是陇南山地亚省、中部干旱地区和陇东高原亚省区划内森林主要害虫名录及主要分布地。     

高温胁迫对植食性昆虫影响研究进展

昆虫作为变温动物类群,极易遭受高温胁迫的影响。研究高温胁迫对植食性昆虫的影响,可为气候变暖背景下农林害虫的种群动态监测及地理适生区预测提供重要理论依据。笔者从植食性昆虫个体、种间互作关系、种群及群落3个层面,综述了高温胁迫对植食性昆虫影响的国内外进展。研究发现,高温胁迫会对植食性昆虫个体的生长发育、繁殖及生理生化带来负面效应,但昆虫自身也会进化出一系列基于形态、行为及基因表达的热胁迫响应机制。高温胁迫对寄主植物、天敌、共生微生物的影响也能够通过种间互作传递给植食性昆虫,并导致寄主植物-植食性昆虫-天敌3级营养关系发生变化。同时,高温胁迫还能通过影响昆虫个体及种间关系,间接影响昆虫的种群动态、种群多样性及其生态功能,并可能导致植食性昆虫的种群大爆发或衰退。最后,笔者认为此领域未来研究方向为:在个体层面上,应优化高温胁迫处理方式并综合考虑干旱和降水等环境因子,开展农林害虫种群的长期野外监测,应注重高温胁迫对昆虫参与生长发育繁殖功能基因的影响;在种间关系层面上,应关注高温胁迫对昆虫关联的复杂多样的食物网及互作体系的影响;此外,应结合高温胁迫对不同昆虫种类自身生理特性和行为模式的影响,阐明温度升高对昆虫群落的影响。     

农业机械领域的工程仿生研究概况与应用前景

工程仿生研究在农业机械领域有着较为广泛的应用,基于昆虫脱附减阻规律与食虫植物捕食现象的研究逐步形成应用于农业生产领域的工程仿生技术。本文从仿生农业机械脱附减阻及致灾农业昆虫滑移捕集滑板仿生制备的研究现状入手,主要分析了典型动植物非光滑表面形态结构对生理功能特性的表现规律与机理,阐述了工程仿生学在农业耕种机械及虫害机械化捕集防治领域的应用研究概况,并分析了工程仿生领域潜在的研究方向与发展前景。     

Activation of a transposable element in the germ line but not the soma of Caenorhabditis elegans

The genetic activity of transposable elements is tightly controlled in many species. Transposons that are relatively quiescent under certain circumstances can excise or transpose at greatly increased rates under other circumstances. For example, 'genomic shock' can activate quiescent maize transposons, 'cytotype' and tissue-specific splicing regulate Drosophila P factors, copy number controls Tn5 transposition in bacteria, and developmental timing affects the production of transposon-like intracisternal A-particles in mouse embryos. The Caenorhabditis elegans transposable element Tc1 is subject to both strain-specific and tissue-specific control. Multiple copies of Tc1 are present in the genome of all C. elegans strains collected from nature. However, these elements are genetically active in only certain isolates. For example, in C. elegans variety Bristol transposition and excision of Tc1 are undetectable, but in variety Bergerac transposition and excision are frequent. Moreover, in variety Bergerac, Tc1 is about 1,000-fold more active in somatic cells than in germ cells. We have investigated the genetic basis for the germ/soma regulation of Tc1 activity. We have isolated mutants that exhibit increased frequencies of Tc1 excision in the germ line. The frequencies of Tc1 excision in the soma are unaltered in these mutants. These mutants also exhibit high frequencies of Tc1 germ-line transposition, and this results in a mutator phenotype. Nearly all mutator-induced mutations are caused by insertion of Tc1.     

九孔鲍肠道及水体中产几丁质酶菌群的测定

通过特定的TCBS(Thiosufate-Citrate-Bile Salts-Sucrose)和筛选培养基,对九孔鲍肠道及其养殖水体中菌群的产几丁质酶能力进行了研究．结果表明,在鲍鱼肠道及其养殖水体中均存在有能分泌几丁质酶的微生物．在鲍鱼肠道中,共分离到12株菌株,占总细菌的34．3％,它们分别属于Vibrio fluvialis和Vibrio minicus;在鲍鱼养殖水体中则分离到4株菌株,占总细菌的11．8％,属于Vibrio fluvialis．比较鲍鱼肠道和养殖水体中产几丁质酶菌株的比例及其能力的大小,可以发现前者的比例高于后者,由此表明了鲍鱼肠道对菌株的选择性．     

DNA sequences at the ends of transposon Tn5 required for transposition

Transposons are a class of genetic elements that can move from one site in a cell's genome to another independently of the cell's general recombination system. Little is known about the mechanism of transposition of compound transposons such as Tn5, but it is thought that a transposon-encoded protein (a transposase) must recognize the outer ends of the element and, together with host factors, catalyse the transfer of the internal DNA into a new site in a manner that may involve replication. It has previously been shown that the synthesis of an IS50R-encoded protein (protein 1) is an essential requirement for Tn5 transposition. Here we demonstrate that a structure containing only the outer 186 base pairs (bp) of both inverted repeats is capable of being efficiently complemented to transpose in Escherichia coli, provided IS50R is located close by on the same replicon. In addition, Bal31-generated deletions indicate that 16-18 bp of the outer end of IS50L are required for transposition. This 16-18-bp sequence contains the 8-9-bp small inverted repeat present at each end of IS50 plus a 9-bp sequence which is homologous to an interrelated sequence present in four copies in the chromosomal origin of replication in a variety of Gram-negative bacteria. This sequence organization suggests that the ends of Tn5 may function to provide a recognition site for the Tn5 transposase adjacent to a sequence recognized by the host replication system.     

甘肃森林昆虫生态地理亚省级区划探讨 Ⅲ.各亚省级区划内森林主要害虫名录及主要分布地(上)

据1981—1982年全省普查,甘肃省的森林害虫,共计664种,隶属于8目98科。本文据笔者二十多年收集的资料和《甘肃省林木病虫普查成果汇编》中所记载的森林主要害虫三百多种,按五个亚省级区计,分别以学名、中名、主要分布地,列表陈述,以供有关高校教学、科研及林业科技人员参考。本文(上)是河西走廊和北山荒漠亚省、祁连山地亚省、甘南高原及峡谷亚省区划内主要森林害虫名录及主要分布地。     

黄瓜山寄生于昆虫内微孢子虫的分布调查

微孢予虫可以侵染大多数的昆虫,包括经济昆虫和农业害虫,并对其造成一定程度甚至是毁灭性的影响．了解微孢子虫在本地区的分布对于农作物害虫的防治和经济昆虫的防疫具有重要意义．本文介绍了黄瓜山地区微孢子虫在昆虫中的分布调查情况,对害虫防治和经济昆虫微孢子虫病的防疫提供了一定的参考和依据．     

贵州省中草药病虫害的现状与防治对策

经过对贵州省中草药病虫害发生与危害调查，26种栽培面积较大的品种共发现害虫47种，病原菌52种，结果表明：白术病毒病、长管蚜，太子参叶斑病，吴茱萸褐天牛，天麻细胸金针虫为近年主要流行病虫害，而农药残留、重金属、亚硝酸盐等有害物质含量的偏高，也严重影响中草药品质，因此防治上在建立完善的植物检疫制度、病虫草害预测预报的同时，加强田间管理，提倡生物防治、物理机械防治、化学防治等有效方法的结合。     

水稻病虫害诊治智能化专家系统

研制开发了水稻病虫鼠害形态识别诊断系统。系统采用智能化农业专家系统技术,对水稻病虫害图像进行采集、数字转化及诊断分析;提取形态特征,识别病虫害发生、发展规律,实现了计算机对水稻病虫害图像、资料自动提取和智能诊断,为水稻栽培的田间管理实现农业知识信息化、沟通指导网络化、科学种田现代化和建立农业网站提供技术和指导。     

新疆昌吉市棉花害虫种类及防治现状调查

对昌吉市棉花害虫种类进行了调查.结果表明:棉花害虫(螨)有17种,其中害螨4种,为害严重的害虫(螨)有棉铃虫、棉蚜、棉叶螨等.文章阐述了昌吉市棉花主要害虫的危害及防治现状,提出了今后对棉花害虫(螨)综合治理的意见和建议.     

Inhibition of bacterial ice nucleators by fish antifreeze glycoproteins

Certain bacteria promote the formation of ice in super-cooled water by means of ice nucleators which contain a unique protein associated with the cell membrane. Ice nucleators in general are believed to act by mimicking the structure of an ice crystal surface, thus imposing an ice-like arrangement on the water molecules in contact with the nucleating surface and lowering the energy necessary for the initiation of ice formation. Quantitative investigation of the bacterial ice-nucleating process has recently been made possible by the discovery of certain bacteria that shed stable membrane vesicles with ice nucleating activity. The opposite effect, inhibition of ice formation, has been described for a group of glycoproteins found in different fish and insect species. This group of substances, termed antifreeze glycoproteins (AFGPs), promotes the supercooling of water with no appreciable effect on the equilibrium freezing point or melting temperature. Substantial evidence now indicates that AFGPs act by binding to a growing ice crystal and slowing crystal growth. As the ice-nucleating protein surface is believed to have a structure similar to an embryonic ice crystal, AFGPs might be predicted to interact directly with a bacterial ice-nucleating site. We report here that AFGPs from the antarctic fish Dissostichus mawsoni inhibit the ice-nucleating activity of membrane vesicles from the bacterium Erwinia herbicola. The inhibition effect shows saturation at high concentration of AFGP and conforms to a simple binding reaction between the AFGP and the nucleation centre.     

沈阳地区京桃主要病虫害的种类及其防治技术的研究

对沈阳地区京桃病虫害种类进行详细调查结果显示：在京桃树木上共发现13种病虫害,其中病害9种,可分为真菌类、细菌类、缺素类3大类,真菌类病害是京桃的主要病原;虫害4种,蚜类、蚧类、天牛类、枯叶蛾类各1种,属于枯叶蛾类的黄褐天幕毛虫危害最重。京桃13种病害的症状和虫害的危害状都有各自典型的特征,易于鉴定和区分京桃病虫害的控制需严格把握以下几点：培育健康苗或栽植壮苗;提高自身的抗病能力;选择土壤条件好的地段、合理控制水分、清除病树并处理;发病后用70％甲基托布津可湿性剂1/1000～1/800倍液防治。     

利用Tn5转座子构建杆状病毒AcMNPV随机突变体的初步研究

以杆状病毒模式种AcMNPV为研究对象,应用基于Tn5转座子的随机转座的方法,构建杆状病毒突变体库将果蝇hsp70启动子后接绿色荧光蛋白基因后插入Tn5转座子,构建了可以在昆虫细胞中表达,易于跟踪的转座载体．利用体外转座系统将转座子随机插入AcMNPV基因组,并用转座反应液转染Sf21细胞,得到了表达绿色荧光蛋白的病毒突变体库进一步纯化了两株病毒B9F和Li6A,进行了转座子插入位点的分析,确定两株病毒中,转座子分别插入了94K基因和p10基因．该方法将为杆状病毒功能基因组研究提供重要的手段。     

Mobilization of a Drosophila transposon in the Caenorhabditis elegans germ line.

Transposons have been enormously useful for genetic analysis in both Drosophila and bacteria. Mutagenic insertions constitute molecular tags that are used to rapidly clone the mutated gene. Such techniques would be especially advantageous in the nematode Caenorhabditis elegans, as the entire sequence of the genome has been determined. Several different types of endogenous transposons are present in C. elegans, and these can be mobilized in mutator strains (reviewed in ref. 1). Unfortunately, use of these native transposons for regulated transposition in C. elegans is limited. First, all strains contain multiple copies of these transposons and thus new insertions do not provide unique tags. Second, mutator strains tend to activate the transposition of several classes of transposons, so that the type of transposon associated with a particular mutation is not known. Here we demonstrate that the Drosophila mariner element Mos1 can be mobilized in C. elegans. First, efficient mobilization of Mos1 is possible in somatic cells. Second, heritable insertions of the transposon can be generated in the germ line. Third, genes that have been mutated by insertion can be rapidly identified using inverse polymerase chain reaction. Fourth, these insertions can subsequently be remobilized to generate deletion and frameshift mutations by imperfect excision.