有机磷农药降解菌木霉FM10的生长条件研究

目的：研究敌敌畏降解菌木霉FM10的生长条件,为该菌的实际应用提供依据.方法：改变单一条件来测定菌株生长变化.结果：木霉FM10对敌敌畏有高效降解性.葡萄糖促进菌株的生长,敌敌畏浓度不高时对菌株影响不大,最适pH为8.0,最适温度是37℃.结论：木霉FM10在自然环境下生长良好,且降解率较高,可用于农药污染的防治.     

4种木霉菌对棉花黄萎病菌抑制作用的测定

以绿色木霉(Trichoderma viride)、康氏木霉(Trichoderma koningii)和二株未知木霉菌株(Trichoderma spp.)为供试木霉菌株,采用对峙培养法测定了不同温度处理下对棉花黄萎病菌(Verticilliam dahliae)的拮抗作用。结果表明,木霉在不同温度下对棉花黄萎病菌的抑制作用不一,其中以30℃和25℃黑暗条件下木霉对棉花黄萎病菌菌丝生长的抑制作用最强,对峙培养5d后,绿色木霉、康氏木霉和二株未知木霉菌在30℃条件下对棉花黄萎病菌的抑制率分别达到67.3%、65.9%、56.8%、65.9%,25℃条件下的抑制率分别为65.9%、72.9%、65.9%、78.8%;20℃下木霉菌株对棉花黄萎病菌的抑制作用次之,10℃、15℃和35℃条件下木霉菌丝扩散速度较慢,且孢子产生量少,不能有效地抑制棉花黄萎病菌菌丝的扩展,表明环境温度过高或过低对木霉菌丝的生长及分生孢子的产生均有较大影响。该研究为筛选棉花黄萎病菌更为有效的生防木霉菌株提供理论依据。     

设施番茄根围土样中木霉菌多样性及功能活性分析

为探索设施栽培条件下蔬菜根围土壤中木霉种群多样性特征及其抗常见植物病原真菌及有机磷农药降解活性,从连续20多年种植番茄的设施大棚根围土样中以及番茄根系内部分离木霉菌,并以tef1-α序列和系统发育分析进行种类鉴定,估算各菌株的相对种群密度;对其生防和农残降解活性进行了测定。结果共分离不同木霉菌株27株,结合形态学特征和tef1-α序列分析,鉴定出分属6个不同的木霉种,即绿色木霉(Trichoderma virens)、深褐木霉(T.atrobrunneum)、西蒙斯木霉(T.simmonsii)、深绿木霉(T.atroviride)、厚木霉(T.crassum)和1个疑似木霉新种(T.sp.nov.);木霉各菌株产孢簇常呈鲜绿色到暗绿色,分布不均匀,常形成同心圆结构。对峙条件下这些木霉对土壤中常见土传病原菌立枯丝核菌(Rhizoctonia solani)、大丽轮枝菌(Verticillium dahliae)、尖孢镰孢菌(Fusarium oxysporum)均有普遍的不同程度的抑菌活性;除深褐木霉两个菌株对毒死蜱的降解效果不明显外,其它种类的木霉均有菌株能有效降解毒死蜱,木霉菌株在根围土壤中的相对种群密度仅为104 cfu/g,且菌株间差异较大。研究结果表明设施农业土壤中木霉菌具有丰富的种质资源多样性,在形态特征及功能活性方面表现明显的菌株差异;木霉对3种常见植物病原真菌有普遍的抑菌作用,少数菌株对常用有机磷农药降解作用明显,可以发挥生防和农化残留降解方面的协同效应。该结果对于研究设施农业土壤中木霉的多样性,指导功能菌株筛选及应用,更好挖掘利用木霉菌资源有着较好的借鉴意义。     

土壤中木霉的分离及其对毒死蜱降解特性研究

为挖掘保护地土壤中的能降解毒死蜱的木霉资源,从长期污染的土壤中共分离6个不同木霉菌株,通过形态学特征和ITS r DNA序列对各菌株进行鉴定,6个菌株分别为哈茨木霉(Trichoderma harzianum)、绿色木霉(T.viride)、康宁木霉(T.koningii)、拟康宁木霉(T.koningiopsis)、长枝木霉(T.longibrachiatum)和短密木霉(T.brevicompactum)。选择降解活性最高的长枝木霉TC5菌株,测定各种条件下对毒死蜱的降解特性。结果表明,木霉TC5在中性或偏碱性条件下对毒死蜱具有更好的降解活性;添加碳源或提高木霉的接种浓度,能提高对毒死蜱的降解活性;在50-300 mg/L范围内,随毒死蜱浓度升高,木霉的降解活性也明显提高。盆栽试验中木霉TC5对毒死蜱保持较强的降解活性,但在自然土壤中降解活性显著低于在灭菌土壤中。分离的木霉菌株在土壤农药污染修复方面具有应用开发潜力。     

低温降解玉米秸秆的木霉菌株筛选

【背景】木霉是自然界中常见的纤维素和半纤维素降解菌,在农业废弃物降解中具有重要应用潜力。【目的】筛选可在低温环境降解玉米秸秆的木霉菌株。【方法】测定31种木霉111个菌株在低温下的生长状况、水解纤维素和木聚糖产生的透明圈直径及部分菌株对玉米秸秆的相对降解率(relativedegradationrate,RDR);利用DNS法测定不同RDR代表菌株的纤维素滤纸酶(filter paper cellulase, FPase)、羧甲基纤维素酶(carboxymethyl cellulase, CMCase)和木聚糖酶(xylanase)活性,并分析它们在不同发酵阶段的酶活与秸秆降解率的关系。【结果】在10℃和5℃培养分别有100株和42株供试菌株能够生长,在15℃均能生长,其中19个菌株培养6 d产生的水解纤维素和木聚糖产生的透明圈直径大于60 mm、培养10 d对玉米秸秆的RDR为0.45%-8.09%;菌株9145、TC425、TC505和8987的FPase、CMCase和xylanase活性随着培养时间呈现动态变化,其中前两者的活性变化趋势基本一致,与RDR的关系密切。【结论】钩状...     

毒死蜱降解木霉菌对几种重要植物病原真菌的生防活性

木霉菌既是广泛应用的防治植物病害的生防菌,又是一类很有应用潜力的环境污染修复菌。针对分离筛选出的6株高效降解毒死蜱的木霉菌株,进行了土传植物真菌病害的生防活性试验。结果表明,在对峙培养条件下,供试木霉菌株对几种病原真菌均具有较为显著的抑制率,发酵滤液对多数病原真菌具有明显的抑菌作用。所有供试木霉菌株能在立枯丝核菌、灰霉、终极腐霉菌落上着生,并逐渐覆盖全部菌落;但不能在茄腐镰孢菌、尖孢镰孢菌、大丽轮枝菌上生长。真菌重寄生现象观察结果表明,供试木霉菌仅对立枯丝核菌具有明显的重寄生现象。研究结果表明,筛选出的高效降解毒死蜱的木霉菌菌株可对多种土传植物病原真菌具有良好的生防潜力。     

福美双农药降解菌的分离与筛选

本研究的目的是筛选出具有降解福美双功能的菌株,并对福美双的降解效果进行评价。通过选择性培养基的富集技术和梯度稀释法从不同烟叶样品和植烟土壤样品中分离筛选出311株农药降解菌株;通过摇瓶培养和高效液相色谱法从311个菌株降解菌中复筛得到5株降解菌。继续从降解福美双能力对5株菌株进行筛选,结果显示:5种菌株中FM84和FM197对福美双的降解率均达到了90%以上。采用16S r DNA序列分析结合细菌常规鉴定方法对菌株进行了初步鉴定,FM84为克雷伯菌属和FM197为肠杆菌属。研究表明,菌株FM84和FM197对福美双有较高并且稳定的降解能力。     

一株降解O,O-二甲基-O-(2,2-二氯乙烯基)磷酸酯的土壤微生物的分离与鉴定(英文)

目的:有机磷农药和杀虫剂广泛应用于众多国内和国外生产的,其数量已超过100种。大量使用的有机磷农药会增加农业生产,而且还造成了不可估量的环境污染。研究降解敌敌畏的微生物,为微生物以降低产品敌敌畏农药残留,恢复敌敌畏污染土壤中的研究奠定基础。方法:本文从种植蔬菜的温室大棚的土壤中分离了一株降解O,O-二甲基-O-(2,2-二氯乙烯基)磷酸酯(敌敌畏)的细菌,根据该菌的形态学、生理生化特征及16S rDNA序列比对。结果:该菌鉴定为荧光假单胞菌(菌株P)。该菌的最适生长温度为27℃,其培养基的最适初始pH为7.0,4天内该菌可将培养液中61.24%的降解。结论:本实验从蔬菜大棚的土样中筛选出一株能降解敌敌畏的菌株,并鉴定为荧光假单胞菌。本研究将为基于微生物以降低产品敌敌畏农药残留,恢复敌敌畏污染土壤中的研究打下基础。     

玉米赤霉烯酮降解菌的鉴定及其降解特性

【背景】玉米赤霉烯酮(Zearalenone,ZEN)是一种具有类雌激素作用的霉菌毒素,常会污染谷物和饲料,严重威胁动物和人类的健康。生物脱毒作为理想的去除ZEN的方法,广受关注,然而相关菌株较少,仍有待进一步筛选。【目的】明确一株玉米赤霉烯酮降解菌的生物学分类地位,并优化其赤霉烯酮降解菌降解条件。【方法】通过菌株的16S rRNA基因序列比对,构建系统发育进化树,并开展了相关培养条件的单因素优化和玉米赤霉烯酮降解动力曲线的绘制。【结果】实验菌株WLB-29经鉴定为斯塔普氏菌属(Stappia),其16S rRNA基因序列在GenBank上登录号为MT196321,该序列与模式菌株Stappia indica B106T相似性最高为97.47%,初步确定为斯塔普氏菌属潜在新种。单因素优化表明,菌株降解玉米赤霉烯酮的最佳条件为LB培养基、37℃培养、pH 8.0、2%接种量和玉米赤霉烯酮初始浓度为10mg/L,在此条件下培养144h后,玉米赤霉烯酮的降解率最高可达92.56%。【结论】菌株WLB-29具有较好的ZEN降解作用,为进一步解析菌株降解ZEN作用机理提供了研究基础,也为进一步开发利用菌株开展ZEN的生物脱毒提供了新的菌株资源。     

耐热木霉菌株筛选及其对热作区香蕉促生效应的研究

[目的]为筛选安全、高效的耐热木霉功能菌株,有效促进热作区香蕉的生产,本研究从热作区土壤分离筛选适温范围较宽的木霉菌株,研制木霉生物有机肥,并研究其对香蕉枯萎病发病率、果实产量及品质的影响.[方法]通过稀释涂布法筛选出木霉菌株,根据菌株在不同温度下的生长情况、拮抗尖孢菌能力及酶活强弱进行菌株复筛;将复筛所得菌株试制成生...     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.