产高温蛋白酶微生物菌种资源的研究

对嗜温及嗜热微生物在不同环境中的分布及其产蛋白酶的情况进行了调查。研究结果显示从常温环境中也有可能分离到具有应用前景的嗜热菌菌株。     

嗜酸嗜热浸矿微生物

随着人们对浸矿菌的研究不断加深,嗜热嗜酸菌的浸矿潜力及在微生物冶金中的作用和地位得到认识,利用嗜热菌对矿石进行高效浸出已成为微生物冶金领域的研究重点。嗜热微生物包括中度嗜热微生物和极端嗜热微生物,主要栖息于热泉、工厂高温废水排放区以及火山口等高温环境中。本综述总结了嗜热浸矿微生物种类,分析了嗜中温菌和极端嗜热菌等嗜酸菌种的生长习性、利用的能源物质、浸矿能力等,并进一步介绍了嗜热嗜酸微生物在高温生物冶金中的发展及应用。     

常温土壤中耐冷菌的分离、鉴定及产酶分析

目的:从常温土壤中筛选冷适应微生物,并进行初步鉴定和产低温酶分析。方法:采集吉首大学校园内土壤样品,通过低温富集培养筛选冷适应微生物;通过形态观察、生理生化特性检测和基于16S rRNA基因序列的系统发育分析,对分离的菌株进行初步鉴定;利用平板筛选法检测其产低温酶特性。结果:分离获得6株耐冷细菌JSBP-1～JSBP-6,初步鉴定其分属假单胞菌属(Pseudomonas)、紫色杆菌属(Janthinobacterium)和节杆菌属(Arthrobacter);在5℃和15℃培养条件下,菌株JSBP-1产蛋白酶能力较强,JSBP-2和JSBP-6产淀粉酶能力较强,JSBP-5仅在5℃条件下有较强的产脂肪酶特性。结论:常温土壤中存在一定数量的冷适应微生物,其中假单胞菌是其优势菌群之一。这类适冷微生物菌群具有潜在的生产低温酶能力。     

固定化酶技术生产天冬素

天冬素(aspartane)是一种低热卡的替代糖精的甜味刑,比一般糖要甜180倍。可用微生物来生产,其产生菌有恶臭假单胞菌,粪产碱杆菌和香气掷孢酵母(sporobolomyces odorus)。荷兰、日本两国合作在欧洲生产天冬素,他们利用嗜热溶蛋白芽孢杆菌(Bacillas thermoproteolyticus)产生的一种蛋白酶,叫嗜热菌蛋白酶。     

极端微生物及其相关功能蛋白研究进展

极端微生物是一类能够适应特殊环境的微生物,相关功能蛋白在其适应极端环境过程中发挥着重要作用,探索极端微生物的特性及其相关的功能蛋白有助于深入了解生命的起源与进化,为蛋白酶在工业领域的应用提供一定理论依据。现概述耐辐射球菌、嗜盐菌、嗜热菌、嗜酸菌和嗜碱菌、嗜冷菌、嗜压菌的特性及其相关的功能蛋白质,从蛋白质水平阐述极端微生物对极端环境的适应机制。     

嗜热菌对有机污染物的降解及其应用研究进展

有机污染物造成的环境问题日趋严重,嗜热菌具有高效降解环境有机污染物的潜力.嗜热菌在高温条件下降解有机污染物,代谢速度快,嗜温杂菌的竞争减少,同时高温环境下一些难降解有机物的溶解度和生物可利用性大大提高,有机污染物可得到快速、彻底降解.因此,嗜热菌对有机废水生物处理及有机物污染场地生物修复等意义重大.本文从嗜热菌降解有机污染物的特点、温度的影响、降解途径、降解酶及其编码基因及工程应用等角度,介绍了嗜热菌降解有机污染物的研究进展,并对嗜热菌降解有机污染物的机理、菌种资源储备、技术策略及应用研发等研究方向进行了展望.     

巴里坤湖和玛纳斯湖嗜盐菌的分离及功能酶的筛选

目的:了解新疆巴里坤湖与马纳斯湖中嗜盐菌及功能酶的多样性。方法:从两湖中采集水样进行菌种分离,采用PCR方法扩增出其16S rRNA基因(16S rDNA),并测定了基因的序列。对分离菌株进行了蛋白酶、淀粉酶、酯酶、脂肪酶、以及纤维素酶的筛选。结果:从两湖水样共分离得到51株嗜盐菌。基于16SrDNA序列的同源性比较和系统发育学分析,发现从两湖分离获得的中度嗜盐菌分别属于Planococcaceae、Bacillacea、Staphylococcus、Halomonadaceae、Salicolaceae以及Pseudomonadacaeae 6个属。分离得到的极端嗜盐古菌属于Halobacteriaceae属。功能酶筛选结果表明产蛋白酶的嗜盐菌共有15株,产酯酶的共有23株,产淀粉酶的共有8株,未获得产脂肪酶和纤维素酶的嗜盐菌。结论:新疆巴里坤湖和马纳斯湖中有丰富的嗜盐微生物资源及酶资源,有重要的研究意义和应用前景。     

一株耐高温细菌CHB1的分离和产酶特性研究

从土壤中分离到1株耐高温细菌CHB1,经鉴定为嗜热脂肪土芽胞杆菌(Geobacillus stearothermophilus)。通过平板透明圈法研究其产酶特性,结果表明CHB1具有蛋白酶、淀粉酶和纤维素酶活性,产酶最适温度均为60℃;最佳产酶时间因酶的种类而不同,淀粉酶为24 h,蛋白酶和纤维素酶为48 h。培养基厚度对产酶有一定的影响,以每皿20~25 mL为宜。     

产低温碱性蛋白酶海洋适冷菌SY的筛选

从连云港海域、港口、远洋捕捞船及鱼市等地采集的海水和各类海鱼、贝类等样品中分离到217株产蛋白酶的细菌,并从中得到1株产低温碱性蛋白酶的海洋适冷细菌—SY。研究表明,该菌株最适生长温度和最适产酶温度均在15℃左右,0℃下仍可生长;具有一定的耐盐性和嗜盐性,无盐条件不能生长,在3%的NaCl盐浓度时,生长达到最高峰;最适生长和最适产酶pH均为8.0;SY菌所产的蛋白酶可能为一种丝氨酸蛋白酶,酶最适作用温度为50℃,最适作用pH为9.0;酶的热稳定性差,50℃保温20min,酶活下降40%。     

一株耐高温细菌CHB1的分离和产酶特性研究

从土壤中分离到1株耐高温细茵CHB1,经鉴定为嗜热脂肪土芽胞杆菌(Geobacillus stearother-mophilus).通过平板透明圈法研究其产酶特性,结果表明CHB1具有蛋白酶、淀粉酶和纤维素酶活性,产酶最适温度均为60℃;最佳产酶时间因酶的种类而不同,淀粉酶为24 h,蛋白酶和纤维素酶为48 h.培养基厚度对产酶有一定的影响,以每皿20～25 mL为宜.     

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.     

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.     

Synthesis and antimicrobial studies of hydrazone derivatives of 4-[3-(2,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid and 4-[3-(3,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid

Microbial resistance to antibiotics is an unresolved global concern, which needs urgent and coordinated action. One of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat antibiotic resistance is the development of new antibiotics to treat drug-resistant bacteria. In our effort to find new antibiotics, we report the synthesis and antimicrobial studies of 30 new pyrazole derivatives. These novel molecules have been synthesized by using readily available starting materials and benign reaction conditions. Some of these molecules have shown activity with MIC values as low as 0.78?µg/mL against four bacterial strains; Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Acinetobacter baumannii. Furthermore, active molecules are non-toxic to mammalian cell line.

     

杆状病毒出芽病毒粒子膜融合蛋白的研究进展

杆状病毒是一类感染节肢动物的病原微生物,其基因组为双链环状DNA,大小为80～180kb.