腾冲热海一株嗜酸热硫化叶菌的分离与鉴定

从云南腾冲热海酸性温泉中分离纯化出一株极端嗜酸热菌株K4-1,并对其进行形态观察、生长特征、碳源和能源利用及16S rRNA基因分析.该菌株细胞形态为不规则球形,有单生鞭毛,严格好氧,兼性自养,能利用元素硫作为能源,也能利用酵母膏、精氨酸或核糖作为碳源和能源.其最适生长温度为75℃,最适pH为3.5.通过16S rRNA基因序列相似性对比对该菌株进行鉴定,结果表明该菌株与硫化叶茵属标准菌株的相似性介于86.6%～94.3%之间,与分离自腾冲热海的腾冲硫化叶菌Sulfolobus tengchongensis RT8-4菌株序列相似性最高,达到98.9%,可将菌株K4-1鉴定为硫化叶菌属菌株.菌株K4-1的16S rRNA基因序列号为EU729124.     

三株氧化硫硫杆菌的分离与鉴定

从煤堆废水中分离得到3株嗜温嗜酸硫氧化细菌.这3株菌株为革兰氏阴性、菌体大小0.4～0.7 μm×1～2 μm、短杆状运动细菌,其最适生长温度为 30 ℃和最适生长pH 2.0～2.5.它们能够利用元素硫,硫代硫酸钠和连四硫酸钾为能源进行自养生长,不能利用有机物质以及硫酸亚铁、黄铁矿和黄铜矿等无机物质作为能源生长.细菌的形态、生理生化特性研究以及基于16S rRNA序列同源性构建的系统发育树结果表明,这3株细菌初步鉴定为氧化硫硫杆菌.氧化硫硫杆菌能够通过产酸有效促进黄铜矿的浸出速率和浸出率.     

鲟源病原性嗜水气单胞菌拮抗芽孢杆菌的鉴定及其生物学特性

从养殖池污泥中分离筛选了1株优良的鲟源嗜水气单胞菌拮抗芽孢杆菌G1,其对鲟源嗜水气单胞菌S1产生的抑菌圈直径为18.50 mm。通过API50CH细菌鉴定系统以及16S rRNA序列分析法,菌株G1被鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens),GenBank登录号HM245965.1,其16S rRNA序列与基因库中芽孢杆菌属菌株的16S rRNA序列有99%100%的同源性,而且与解淀粉芽孢杆菌Ba-74501(GenBank登录号:DQ422953.1)的亲缘关系最近。菌株G1的最适生长pH值为7,最适生长温度为30°C,其在30°C、200 r/min条件下的生长曲线为:0 6 h为生长延迟期,6 54 h为对数生长期,54 90 h为稳定期,90 h以后为衰亡期。此外,菌株G1对其他实验选用的病原性嗜水气单胞菌也表现出良好的拮抗活性。本实验结果有利于填补嗜水气单胞菌拮抗菌在分类地位、生物学特性等方面的不足,为鲟鱼嗜水气单胞菌病的生物防控提供科学资料。     

硫代硫酸盐氧化菌TX的分离、鉴定及其生物学特性

从聚硫橡胶废水处理系统中分离到一株硫代硫酸盐氧化细菌TX.根据其形态学特征、生理特征和16S rRNA基因序列相似性分析,将该菌株初步鉴定为盐生硫杆菌属(Halothiobacillus sp.)(GenBank登录号为EU871645).该菌株能利用硫代硫酸盐、单质硫、连四硫酸盐、硫化物或亚硫酸盐为唯一能源进行自养生长,不能利用葡萄糖、蔗糖、果糖、乳糖、麦芽糖或酵母粉进行异养生长,为专性化能无机自养型硫杆菌.在以硫代硫酸钠为唯一能源的培养基中其最适生长温度为30℃～35℃,最适起始pH值为3.0～5.0.在矿物盐培养基中,硫代硫酸盐最终被氧化成硫酸,造成培养基pH持续下降.在摇瓶分批培养和硫胶废水处理过程中均检测到连四硫酸盐的积累,表明该菌株主要通过连四硫酸盐途径或"S4I"途径进行硫代硫酸盐的生物氧化.     

一株反硝化光合细菌的生物学特性及系统发育分析

【目的】养殖水体中亚硝酸盐的过量积累会对养殖生物产生毒害作用,应用脱氮细菌去除亚硝酸盐是养殖水质调控的重要手段之一,本文意在得到一株高效去除亚硝酸盐的光合细菌。【方法】采用软琼脂稀释法分离纯化光合细菌菌株,通过电镜观察、生理生化试验研究其生物学特性、依据16S rDNA和光合反应中心M亚基基因(Gene coding for photosynthetic reaction center subunit M,pufM)序列对其做系统发育分析。【结果】从淡水养殖塘中分离筛选到一株高效还原亚硝氮的光合细菌菌株wps。该菌株为革兰氏阴性菌,细胞杆状,大小为0.4-0.6μm×1.5-4.0μm,极生丛生鞭毛,片层状光合内膜,兼性厌氧光照条件生长,单菌落及液体培养物呈红色,含细菌叶绿素a和类胡萝卜素。最适生长pH范围为5.5-8.5,最适生长盐度范围为0-2%,最适生长温度范围为25℃-38℃。菌株wps与Rhodopseudomonas palustris的16S rDNA序列相似性为98.9%,光合反应中心M亚基基因序列的相似性为94.9%,但是二者在生物学性质上有较大差异,如菌株wps在pH5.5生长,不能光自养生长,不利用柠檬酸盐、甲酸盐进行光异养生长,需盐酸硫胺素和泛酸钙做生长因子等。【结论】菌株wps可能为Rhodopseudomonas属的一个新种,且在养殖水体水质调控中具有重要应用前景。     

一株中度嗜热嗜酸铁氧化细菌特性研究*

从我国煤矿废石堆分离到一株中度嗜热嗜酸铁氧化细菌MLY菌株,最适生长温度50℃－54℃,最适pH1.2-1.4。MLY菌株是兼性化能自养菌,能利用酵母粉异养生长。在自养和混合营养条件下,能氧化Fe^2 、黄铁矿(FeS2)和元素硫(S^0)。自养营养时,氧化元素硫较弱。对比研究MLY菌株和氧化亚铁硫杆菌(Thiobacillus ferrooxidans)A10菌株对Fe^2 和黄铁矿的氧化作用,结果表明,MLY比A10的氧化速度快1倍多。     

一株中度嗜热嗜酸硫氧化杆菌的分离和系统发育分析

从云南腾冲温泉酸性水样分离得到一株中度嗜热嗜酸硫氧化杆菌MTH 0 4 ,对分离菌株进行了形态、生理生化特性研究及 1 6SrDNA序列分析。该菌株为革兰氏阴性细菌 ,短杆状 ,菌体大小 (0 6～ 0 8) μm× (1～ 2 ) μm ,化能自养 ,可利用硫磺、四硫酸盐、硫代硫酸盐为能源生长 ,不能利用蛋白胨、葡萄糖、酵母粉 ,也不能进行混合型生长。最适生长温度在 4 0℃～ 4 5℃之间 ,最适生长pH 2 0～ 3 0 ,代时 8h。以 1 6SrDNA序列同源性为基础构建了包括 1 3株相关种属在内的系统发育树 ,结果表明 ,MTH 0 4与喜温硫杆菌 (Thiobacilluscaldus)处于同一进化树分支中 ,相似性达 99 5 %以上     

深海热液区超嗜热古菌Thermococcus sp. TVG2的培养分离与鉴定

【目的】培养分离大西洋脊热液区的超嗜热古菌,为进一步认识该生态系统中的物种及其特点奠定基础。【方法】将大西洋脊热液区海水样品用YTSV培养基富集培养,选取其中富集效果最佳的TVG2培养物用减绝稀释法分离纯化。对所分离菌株进行形态、生理生化特征等分析,并通过分子生物学手段对其进行初步鉴定。【结果】菌株TVG2属于超嗜热厌氧球菌,直径约1.0 μm;生长温度范围50?88 °C,最适生长温度82 °C;生长pH范围为5.0?9.0,最适生长pH 6.5;生长NaCl浓度为1.0%?4.0% (质量体积比),最适生长浓度为2.5%;元素硫可显著提高菌株TVG2的生物量,但非生长必需;丙酮酸钠能显著促进该菌株生长,但葡萄糖对其生长则有抑制作用。根据其形态特征、生理生化特性及16S rRNA基因序列分析,确定菌株TVG2属于热球菌属。【结论】用YTSV培养基从大西洋脊热液区样品中分离获得超嗜热厌氧菌株TVG2,并确定其为Thermococcus属成员,命名为Thermococcus sp. TVG2。     

高温油藏采出液中嗜热产甲烷古菌的分离鉴定

为了进一步从高温油藏中发掘新的微生物种质资源,采用Hungate厌氧操作技术从大港油田油井采出水中分离出一株嗜热自养产甲烷杆菌DL-7。生理生化结果显示菌株DL-7只能够利用H2/CO2生长,不利用甲酸、甲醇、三甲胺、乙酸和二级醇类;最适生长温度60℃;最适盐浓度0.8 g/L;最适pH为7.0～7.5;只有在添加酵母粉的培养基中才可以较好生长。16S rRNA序列比对结果显示菌株DL-7与标准株M.marburgensis DSM 2133T(X15364)的16S rRNA基因序列相似性为99.7%。     

近江牡蛎共附生耐热真菌C051的鉴定、生理学特性及抗菌活性研究

为进一步开发利用耐热海洋真菌,以1株近江牡蛎共附生耐热真菌C051为出发菌株,对其进行系统鉴定、生理学特性及抗菌活性研究。采用形态学鉴定并结合18S rRNA序列分析,确定菌株C051为烟曲霉(Aspergillus fumigatus)。3种培养基比较,适合基础培养基为PDA;生长温度范围为15～50℃,最适生长温度45℃,具有明显的耐热真菌特性;生长pH范围3～9,最适生长pH 6;生长盐浓度0%～16%,最适生长盐浓度3.5%,具兼性海洋真菌的特点。其发酵产物对铜绿假单胞菌(Pseudomons aeruginosa)、金黄色葡萄球菌(Staphylococcus aureus)、交替假单胞菌属SL-1(Pseudoalteromonas sp.)、金黄杆菌属SL-4(Chryseobacterium sp.)均有良好的抑菌效果,最大抑菌圈直径达22.15 mm,为耐热海洋真菌的开发与研究提供参考。     

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.