1株耐高温生物表面活性剂产生菌的特性研究

研究了耐高温生物表面活性剂产生菌ZY-3的生理生化特性,并通过测定发酵液的菌体密度、表面张力和乳化活性等指标,研究不同碳源和初始pH对菌株ZY-3生长和产生物表面活性剂的影响,同时对其所产生物表面活性剂进行了初步分离和性质分析。菌株ZY-3被初步鉴定为芽胞杆菌属(Bacillus),具有产酸、不产H_2S、还原硝酸盐等特性。在以淀粉为碳源、初始pH 6.0的培养基中发酵,产生物表面活性剂多且稳定;在种子培养基和发酵培养基中都有淀粉的条件下,菌体生长较多,降低表面张力和乳化的作用均较强,所产生物表面活性剂可以使发酵液的表面张力从72.1 mN/m降到53.1 mN/m,乳化活性从0升高到24%。初步判断产物为糖脂类阴离子表面活性剂。     

高效生物表面活性剂产生菌筛选及其性质研究

目的:获得产高效生物表面活性剂的菌株并获得优化培养基。方法:通过从山东文登某加油站附近长期污染富含油质的土壤中逐步采用富集培养基和平板筛选培养基分离筛选菌株并进行优化培养寻找最优生长培养和高产生物表面活性剂的条件。结果:筛选出产表面活性剂的微生物12株,分别命名为BSF1#-BSF12#,从中筛选出1株高效表面活性剂产生菌BSF8#,优化培养结果表明BSF8#的最佳生长pH在7.5左右,最佳碳源为葡萄糖,最佳氮源为蛋白胨,BSF8#培养基中最佳NaCl浓度为2g/L。BSF8#菌株可将发酵液的表面张力由最初的48.29mN/m降到27.79 mN/m,上层乳化状发酵液的排油圈最大直径超过7.5cm,并经红外光谱分析确定其生物表面活性剂为1个糖肽类化合物。结论:BSF8#菌株产生的生物表面活性剂活性突出,有较大的开发潜力。     

一株高效表面活性剂产生菌的筛选及其活性产物的结构与性质

采用血平板法结合表面张力法从大庆油田高台子低渗透油藏采出水中筛选出一株高效表面活性剂产生菌,编号为DY-9.16S rDNA序列同源性比对结果显示,DY-9与地衣芽孢杆菌(Bacillus licheniformis)的序列相似性达99％.在45℃、180 r·min-1振荡培养条件下,DY-9在20 g·L-1糖蜜为碳源的培养基中生长良好,24h内将发酵液的表面张力从初始的69.3 mN·m-1降低至26.5 mN·m-1.48 h发酵液中表面活性剂粗品的产量达0.48 g·L-1,其临界胶束浓度为28 mg·L-1.菌株产生的表面活性剂在高温(120℃,1h)、高盐(12％ NaCl)及较宽的pH(2～12)条件下保持稳定,溶液的表面张力低于30 mN·m-1.经傅里叶变换红外光谱(IF-TR)和高效液相色谱-质谱联用(HPLC-MS)分析,菌株DY-9的表面活性产物为环状脂肽类表面活性剂.     

产生物表面活性剂菌种的一种快速筛选模型*

利用生物表面活性剂具有溶血性和在产生过程中能使蓝色凝胶平板变色等特性,建立了产生物表面活性剂菌种的快速筛选模型。模型用于从采自油田和炼厂的土样和水样中筛选生物表面活性剂产生菌,选出12株能产生物表面活性剂的微生物,其中1株糖脂产量为6．5g／L,产生的糖脂配成0．5％水溶液,能在25％将水的表面张力从71．3mN／m降到30．5mN／m。     

一株表面活性剂产生菌的筛选及其特性研究

从氧化沟含油污水中分离得到1株能产生物表面活性剂菌株S6(Pseudomonas sp.),经生理生化实验和16SrDNA序列分析鉴定,S6为铜绿假单胞菌。红外光谱分析得知S6在代谢过程中能够产生糖脂类表面活性物质。其临界胶束浓度(CMC)为50mg/L,可将水的表面张力由72mN/m降到33.9mN/m。发酵液的表面张力和排油直径的测定结果显示发酵液在不同的盐度、pH和溶解氧量条件下,具有较稳定的表面活性。通过正交实验确定了优化培养基条件为葡萄糖10g、尿素5g、磷酸二氢钾1g、微量元素液2mL、pH8.0、水1000mL;S6在优化培养基中合成生物表面活性剂的产量为0.173g/L。     

石油降解菌X-1所产表面活性剂的研究

对石油污染土壤中筛选到的能产生生物表面活性剂的石油降解菌X-1(芽孢杆菌),进行表面活性剂的提取和鉴定,并对其产剂条件进行了优化。结果表明:菌株X-1产生的生物表面活性剂为浅黄色粉末状物质。通过硅胶板薄层层析和红外光谱分析,判定表面活性剂为脂肽、脂蛋白类物质。菌株X-1产生表面活性剂的最佳条件为:温度32℃,pH 7.0,盐度2 g/L NaCl,最佳碳源为淀粉,最佳氮源为蛋白胨。     

假丝酵母产生物表面活性剂的研究

从扬子石化的废水淤泥中筛选到1株假丝酵母(Candida),其发酵上清液有较强的表面活性,可将水的表面张力从72.3mN/m降到32.5mN/m。发酵上清液经酸化、丙酮沉淀后得到浅黄色固体,经TLC、IR、GC-MS分析表明:此种物质为脂肽类物质,疏水基部分为十六碳酸和9-十八烯酸,亲水基部分含有多种氨基酸。其临界胶束质量浓度为150mg/L,可耐受120℃高温和饱和浓度盐离子(质量分数为36%的Na+),pH适应范围广(pH2～12),是一种极具应用前景的生物表面活性剂。     

表面活性剂产生菌SQ6:筛选及其发酵液表面活性

从大庆油田油藏采出水中成功筛选获得一株表面活性剂产生菌,编号为SQ6,该菌为短杆状革兰氏阴性菌。16S rRNA基因序列比对结果显示,SQ6与铜绿假单胞菌(Pseudomonas aeruginosa)序列相似性达到99.9%;生理生化鉴定结果进一步表明,SQ6符合假单胞菌属特征。以葡萄糖为碳源,24h内SQ6发酵液表面张力(ST)从57.0mN·m-1降至25.6mN·m-1。SQ6发酵液在高温(121℃,30min)、高盐(NaCl浓度为12%)和广泛pH条件下保持较稳定的表面活性,其临界胶束浓度(CMC)为50mg·L-1。薄层层析结果显示,SQ6发酵液表面活性成分主要为糖脂类。     

一株产脂肽类表面活性剂的碱性Dietzia菌及特性研究

【目的】筛选降解性能良好的产生物表面活性剂的菌株,对其进行分类学鉴定,确定所产表面活性剂物质并对各影响因素进行评价。【方法】利用液体石蜡为底物筛选降解性能良好的产生物表面活性剂菌株,通过形态特征观察、生理生化测定、16S rRNA基因序列分析等实验确定菌株的分类地位。通过排油圈活性、表面张力值、薄层层析等方法确定生物表面活性剂的性质,分析碳、氮源和温度、pH、盐浓度各因素对菌株产生物表面活性剂的影响。【结果】从大连新港采集的样品中分离得到一株产表面活性剂的嗜碱菌株3372,经分类鉴定表明其是Dietzia cercidiphylli的新菌株。嗜碱菌3372发酵液粗提物的排油直径为6.1 cm,表面张力可从67.62 mN/m降到32.95 mN/m,经薄层层析分析,初步鉴定为脂肽类表面活性剂。综合各因素对发酵液表面活性的影响,菌株3372在pH为9.0、适盐浓度为3%的培养基中,经30°C培养可将发酵液表面张力值降到最低。【结论】嗜碱菌3372是脂肽类生物表面活性剂产生菌的新成员,其在高盐碱条件下产生表面活性剂的特性在工业应用上有一定的潜力。     

驱油生物表面活性剂生产菌的筛选与评价

目的:筛选适合油田的生物表面活性剂生产菌。方法:通过发酵培养,研究生物表面活性剂生产菌生长代谢规律;采用正交试验法,优选出其最佳培养条件;通过室内驱油实验评价生物表面活性剂驱油效果。结果:2#菌株最佳培养时间为96小时,最优发酵培养条件为:葡萄糖4.0 g、玉米浆1.6 g、Na2HPO40.1 g、KH2PO40.05 g、MgSO40.05 g、CaCl20.005 g、水100 mL、pH 7.2,培养温度35℃,摇床转速120 r/min,生物表面活性剂驱油提高采收率6.16%。结论:筛选出最优生物表面活性剂产生菌2#,菌株具备产表面活性剂的能力且产物量较高,其生物表面活性剂驱油效果良好。     

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.