嗜热菌——工业用酶的新来源

综述了嗜热菌和极端嗜热菌产生的热稳定性的淀粉酶、纤维素酶、环糊精酶、木聚糖酶、几丁质酶、葡萄糖异构酶、蛋白酶等的研究进展及其在食品、化工、环保等方面的应用前景。     

嗜热菌耐热机理的研究进展

只在55℃以上的环境中生长的微生物叫嗜热菌。从嗜热菌细胞膜的组成、酶的热稳定性,以及DNA、RNA的耐热机理等方面予以综述,介绍国内外近年来的研究进展。     

嗜热菌的耐热分子机制

对嗜热菌耐热机制在其细胞表层结构、ＤＮＡ螺旋的热稳定性和嗜热菌酶耐热性等方面的研究作一综述。     

小分子封闭提高固定化嗜热菌蛋白酶的热稳定性

为了提高固定化嗜热菌蛋白酶的热稳定性,在制备共价固定化嗜热菌蛋白酶的基础上,通过选择氨基酸和醇类小分子来封闭载体表面未反应的活化基团,并考察了固定化酶的催化活性及热稳定性。结果发现：L-Trp和L-Val封闭修饰固定化酶时,在80℃的水浴中加热150 min后其剩余活力仍为93.4%和98.6%,其效果约为未经小分子封闭的固定化嗜热菌蛋白酶的2倍。所筛选的几种小分子物质中,叔戊醇、L-Trp、L-Val及L-Ala不仅能提高固定化嗜热菌蛋白酶的热稳定性,而且也可以提高固定化酶的相对活力,从而更有利于其在工业生产中的应用。     

极瑞环境下的生命

极端微生物是依赖于一种或多种极端物化因子的特殊生命形式，在100℃以上或0℃以下、近饱和的盐度、pH〉10或PH〈2等极端环境下，具有极端的生命世界，已发现的极端生命形式包括嗜热菌、嗜冷菌、嗜碱菌、嗜酸菌、嗜盐菌、嗜压菌等，统称为极端微生物，它们构成了地球生命形式的独特风景线，其存在的原理与意义为更好地认知生命现象、发展生物技术提供了宝贵的知识源泉。     

耐热型α-葡萄糖苷酶基因在大肠杆菌中的克隆及表达

应用PCR法从火山口嗜热菌中克隆出了α-葡萄糖苷酶基因,并将该基因导入大肠杆菌,获得了稳定表达的大肠杆菌菌株。同时对其表达产物进行了酶学性质分析。结果表明：该基因长1587bp,编码501个氨基酸,为新舡葡萄糖苷酶同源基因,已将该序列在Genbank中登记;其表达产物经SDS-PAGE分析表明,相对分子质量约为66kD;该α-葡萄糖苷酶的最适温度为90℃,最适pH值为7．0,在80℃放置3h,酶活仍能达到94％以上。结果表明该酶具有优良的耐热性,将有广泛的工业应用前景。     

一种有效的嗜热真菌杜邦嗜热菌靶向基因替代系统

以嗜热真菌杜邦嗜热菌Thermomyces dupontii NRRL 2155为研究材料,利用同源重组原理和真菌原生质体转化方法,以潮霉素抗性基因替换嗜热真菌目标基因,获得抗潮霉素的靶向基因敲除突变菌株。优化的遗传转化体系为：用15mg/mL裂解酶,在28℃下酶解2g杜邦嗜热菌菌丝5.5h以获得原生质体,经STC缓冲液洗涤重悬后,利用PEG（polyethylene glycol）介导的遗传转化方式,将10μg线性敲除全长片段转化至杜邦嗜热菌原生质体中,通过潮霉素筛选及PCR验证得到基因替换突变菌株,同源重组率达到20%。本研究首次将原生质体转化方法应用在杜邦嗜热菌,并成功建立稳定高效的基因替换体系,为快速构建杜邦嗜热菌的遗传转化体系和研究该嗜热真菌的基因功能提供有效方法。     

极端环境下的生命

极端微生物是依赖于一种或多种极端物化因子的特殊生命形式,在100℃以上或0℃以下、近饱和的盐度、pH>10或pH<2等极端环境下,具有极端的生命世界,已发现的极端生命形式包括嗜热菌、嗜冷菌、     

嗜热菌在纤维素乙醇中的研究进展及应用前景

利用纤维素生产乙醇的研究中,传统的中温微生物在基质范围、酶活性及热稳定性等方面存在不足,难以满足工业需求.嗜热菌具有独特的降解纤维素、半纤维素和生产乙醇的耐高温酶系和代谢途径,不但热稳定性高、而且底物范围广泛,在生物质能学领域有重要的研究价值和应用潜力.综述了在纤维素乙醇研究中具有潜力的嗜热菌的种类、特性、代谢机理和研究进展,并对嗜热菌的应用前景进行了分析与展望.     

嗜热酶的特性及其应用

海洋微生物作为一类生长在特殊极端环境下的生物正日益引起人们的重视。其中嗜热微生物由于能在高温温泉及火山口附近的高热环境下生长而引起人们的极大关注[1] 。同时 ,人们也从许多人工高热环境 (如堆肥 )中分离得到这种嗜热菌。近年来 ,人们从这些嗜热菌中已分离得到多种嗜热酶 (5 5℃～80℃ )及超级嗜热酶 (80℃～ 1 1 3℃ ) [2 ] 。嗜热酶不仅具有化学催化剂无法比拟的优点 ,如催化效率高和底物专一性强 ,而且酶在高温条件下的稳定性极好[3 ] 。因而它可以克服中温酶 (2 0℃～ 5 5℃ )及低温酶 (-2℃～ 2 0℃ )在应用过程中常常出现的…     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

医疗机构合理用药评价模型的构建研究

目的 针对医疗机构的合理用药水平进行评价研究。方法 根据医疗机构合理用药的具体要求,构建医疗机构合理用药评价指标体系,采用基于模糊群决策的方法和多指标评价分析法构建医疗机构合理用药评价模型。结果 构建了基于模糊群决策的医疗机构合理用药评价模型,并通过实例分析证明了评价模型的可行性。结论 建立的基于模糊群决策的医疗机构合理用药评价模型能够对医疗机构的合理用药水平进行科学评价,为提高医疗机构合理用药水平奠定基础。     

棉铃虫钙粘蛋白N端多肽多克隆抗体制备及对Bt抗性的初步检测

用重组表达的棉铃虫Helicoverpa armigera(Hübner)中肠钙粘蛋白N端多肽片段制备兔多克隆抗体,并利用其对Bt抗性进行鉴定。通过RT-PCR方法对棉铃虫中肠钙粘蛋白N端多肽的基因片段Cad285进行PCR扩增,将其克隆到pET-30a原核表达载体中,在大肠杆菌BL21(DE3)中经IPTG诱导表达,得到35ku的重组融和蛋白,融合表达的包涵体经过变性、Ni-NTA柱亲和纯化、复性等方法处理包涵体,获得可溶性纯化蛋白,用纯化后蛋白免疫新西兰兔制备多克隆抗体,ELISA检测其效价高于1∶16000;利用最终获得的多克隆抗体对室内纯合Bt抗/感品系的棉铃虫中肠钙粘蛋白进行Western blot分析,结果显示敏感和抗性品系之间有明显差异,表明其能够应用对Bt抗性进行初步检测。