解淀粉芽孢杆菌BA-26抗菌物质分离及对灰葡萄孢抑菌作用研究

分析解淀粉芽孢杆菌(Bacillus amyloliquefaciens)BA-26发酵液中抑菌物质存在情况,明确活性物质的抑菌效果,初步探索其抗植物病原真菌的作用机制。通过硫酸铵沉淀、大孔树脂吸附及反相高效液相色谱法(RP-HPLC),从菌株BA-26的发酵液中分离纯化抗菌物质;采用平板对峙法检测抗菌物质抑菌活性;用二倍稀释法测定各活性组分的最小抑菌浓度(MIC),并研究其对菌丝和孢子萌发的影响。从菌株BA-26发酵液中获得抗菌粗提物抑菌谱广,对立枯丝核菌等多种植物病原真菌有强抑制作用;分离纯化得到11个具有抑制真菌作用的活性组分;其中A6-19和A6-20组分对灰葡萄孢(Botrytis cinerea)抑菌活性最强,最小抑菌浓度为7.81μg/mL;菌株BA-26产生的抗真菌活性物质能使灰葡萄孢菌丝生长受阻、膨大变粗、细胞膜破坏并能抑制其孢子萌发。明确了解淀粉芽孢杆菌BA-26菌株产抗菌物质情况,初步探究其抑菌作用机制,为抗菌物质在防治病原真菌等方面的应用奠定基础。     

北细辛内生真菌的分离鉴定及代谢产物的生物活性

采用表面消毒法分别从3种北细辛中分离获得10株形态特征不同的优势内生真菌,经形态学和18S rDNA ITS分子分类学分析鉴定为小丛壳属(Glomerella sp.)、叶点霉属(Phyllosticta sp.)、柄孢壳菌属(Po-dospora sp.)、刺盘孢属(Colletotrichum sp.)和镰孢属(Fusarium sp.)。对北细辛优势内生真菌的发酵产物进行体外抗肿瘤和抗菌活性检测,结果表明:除菌株E3、E4和E10外,其余菌株均有不同程度的抗肿瘤和抗菌活性;镰孢属(Fusarium sp.)菌株E9对A549、MDA-MB-231和PANC-1肿瘤细胞抑制率达75%以上;小丛壳属(Glomerella sp.)菌株E1和叶点霉属(Phyllosticta sp.)菌株E2靶向FabI的抗菌活性较强,抑制率达59%。     

响应面法优化生防菌吡咯伯克霍尔德氏菌JK-SH007的发酵工艺

以吡咯伯克霍尔德氏菌Burkholderia pyrrocinia JK-SH007为出发菌株,对其发酵工艺进行优化,以期提高发酵效率.通过筛选试验、最陡爬坡试验和响应面分析确定影响JK-SH007菌株生长最重要两因素为玉米浆和葡萄糖,其最佳浓度分别为13.88 g/L和3.37 g/L.优化后的发酵工艺培养该菌浓度可达1.18×109 CFU/mL,比优化前提高1.35倍,抑菌活性提高28.84％.     

球形芽孢杆菌C3-41菌株杀蚊毒素的提取及其同源性研究

从球形芽孢杆菌C3-41菌株芽孢-晶体复合物中分别提取孢壁蛋白(S蛋白)和孢晶毒素。采用SDS-PAGE证明孢晶毒素具有43和40kD两种多肽。但S蛋白只有一条104kD的蛋白带。后者经NaOH处理迅速降解成43和40kD的多肽。S蛋白和用SephadexG-75提纯的孢晶毒素对三龄致倦库蚊幼虫的LC50值(48h)分别为267和10ng／ml。免疫双扩散试验证明2362,1593、Bs-10(H5a5b)和2297(H25)菌株的孢晶毒素能与C3-41菌株的孢晶毒素抗血清发生交叉反应,但K(H1)、SSH-1、1404(H2)和2315(H26)菌抹的孢晶毒素与此抗血清不发生交叉反应。同时还证明Cr41菌株的S蛋白和孢晶毒索具有抗原同源性。     

不同虫花棒束孢菌株固体培养提取物抗氧化和抗菌活性初步测定

虫花棒束孢(Isaria farinosa)是一种常见的土栖昆虫病原真菌,在害虫生物防治方面有着广泛研究和应用,其对人体保健、药效和活性成分等方面也有一定的研究。为了揭示不同菌株之间的差异,选择7个来源不同的菌株,经形态和分子鉴定后,通过大米固体培养和乙酸乙酯提取,进行了抗氧化和抗菌活性测定。研究结果表明不同来源的虫花棒束孢菌株,经相同条件的培养和提取得到的产物在抗氧化和抗菌活性方面呈现明显的差异,以菌株2142表现最佳,在抗菌实验中尤其突出。菌株2142乙酸乙酯粗提物(200 mg/m L)对蜡样芽胞杆菌的抗菌活性达到与阳性对照氨苄西林钠(80μg/m L)相似的水平。该菌株具有较好的应用前景,有待进一步深入研究。利用虫花棒束孢菌株研发保健产品或医药产品具有很好的潜力,但其菌株来源需要十分关注;筛选对人体安全可靠,并有利于产品开发利用的优良菌株是一项非常重要的工作。     

生防细菌ML-3抗菌蛋白发酵条件的优化及其防治应用

明确菌株ML-3抗菌蛋白对马铃薯早疫病的防效效果,为马铃薯早疫病生物防治提供参考依据。本研究采用硫酸铵分级沉淀、琼脂扩散法、正交试验、田间试验以及16S rDNA系统进化分析相结合的方法对菌株ML-3产抗菌蛋白的较优碳源、氮源、发酵条件、最佳硫酸铵沉淀浓度、抑菌稳定性、马铃薯早疫病田间防效和分类地位进行了研究。结果表明:该菌株产生的抗菌蛋白最佳发酵液配方为2%马铃薯、1%蛋白胨和0.5%NaCl,最佳发酵条件为:初始pH值7.0、温度30℃、装液量400 mL/500 mL、接种量5 mL、发酵48 h;抗菌蛋白在温度≤60℃、pH值5-8和紫外照射36 h内具有良好稳定性,而且对K~+、Fe~(2+)、Zn~(2+)、Na~+稳定性较好;马铃薯早疫病防治的田间用药浓度为≥10 mg/L;使用16S rDNA序列可将该菌株鉴定为枯草芽孢杆菌沙漠亚种(Bacillus subtilis subsp.inaquosorum)。说明菌株ML-3抗菌蛋白在防治马铃薯早疫病和生物农药开发中应用潜力明显。     

解淀粉芽孢杆菌TF28抗菌脂肽芬芥素的分离鉴定及抑菌作用

对一株解淀粉芽孢杆菌TF28产生的抗菌脂肽进行分离鉴定及抑菌活性研究,采用酸沉淀、乙酸乙酯和甲醇萃取技术制备了抗菌脂肽粗提物,经过2次HPLC分离纯化,在保留时间32～42min内获得8个抗菌脂肽纯品,经MALDI-TOF-MS鉴定为芬芥素(fengycins),对尖孢镰刀菌和禾谷镰刀菌显示出较强的抑菌活性,该研究为提高菌株TF28抗菌脂肽产量的定向遗传改造奠定基础。     

陕西省烟草灰霉病病原及云芝多糖对其防治研究

采用形态学观察和分子鉴定方法对2011年在陕西省发生的一种烟草未知病害的病原菌进行鉴定。从病叶组织分离纯化得到病原菌,通过致病性测定以及人工接种后再分离病菌,证明编号LJL007的菌株为该病的致病菌。依据病原菌的形态学和培养特征,将菌株LJL007鉴定为灰葡萄孢Botrytis cinerea Pers.,其有性型为富氏葡萄孢盘菌Botryotinia fuckeliana Whetzel。通过核糖体DNAITS序列分析,分离菌株LJL007序列(登录号:HM17900)与富氏葡萄孢盘菌序列(登录号:HM849615)同源性达100%,进一步证明该病原菌是灰葡萄孢Botrytis cinerea。云芝多糖在离体条件下,对灰葡萄孢的菌丝生长和孢子萌发均无直接抑制作用。云芝多糖对烟草灰霉病有较好预防保护作用,其预防效果可达56.29%。云芝多糖可显著提高烟草体内几丁质酶和β-1,3-葡聚糖酶活性,其活性峰值分别比对照提高56.89%和429.83%,说明云芝多糖可诱导植物产生抗病性。     

杨树溃疡病生防菌株N6-34抗菌活性物质的分离纯化与结构鉴定

【背景】杨树溃疡病是一种主要由葡萄座腔菌引起的杨树枝干病害,危害严重。前期从杨树中分离到一株内生拮抗细菌N6-34,研究表明该菌株拮抗效果好,对多种植物病原菌均有较强的拮抗作用。【目的】对拮抗细菌N6-34产生的抗菌活性物质进行分离纯化,并鉴定了活性物质组分的结构。【方法】通过硫酸铵盐析、甲醇抽提、分子筛、高效液相色谱等方法分离纯化N6-34菌株的抗菌活性物质,并对其进行结构鉴定。【结果】N6-34菌株发酵液经多步分离纯化,共获得14个组分,其中有13个组分具有抗菌活性,经一级质谱分析,获得了13种抗菌活性组分的分子量;经二级质谱分析,将13种抗菌活性物质鉴定为Fengycin A或Fengycin B的同系物或同分异构体。【结论】从N6-34菌株发酵液中分离获得了13种抗菌成分,为杨树溃疡病的生物防治提供了理论依据。     

金黄壳囊孢菌侵染过程中银中杨锌指蛋白基因的表达

研究了银中杨接种金黄壳囊孢菌后锌指蛋白基因的表达,为林木抗病遗传育种工作奠定基础。从杨树上分离得到了一株杨树烂皮病菌(CHH001),测定其对银中杨的致病力,并采用形态学和ITS-PCR鉴定方法鉴定该菌株为金黄壳囊孢菌。采用实时定量荧光PCR技术对银中杨接种金黄壳囊孢菌后锌指蛋白基因的表达进行了研究。实验结果显示,ZFP1和69-Ⅳ-2-4在接种后表达水平持续上升,ZFP1在48 h的基因表达量分别为烫伤对照和空白对照的4.21倍和3.11倍;69-Ⅳ-2-4在48 h为烫伤对照和空白对照的9.56和7.06倍。ZFP1和69-Ⅳ-2-4在接种前期高表达,表明可能参与了植物与病原物的识别过程和防御反应。     

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.