一种新型的杀菌灭藻剂U_1

U_1是我们研制成功的一种新型杀菌灭藻剂。其有效成分是二硫氰基甲烷和二氯异氰尿酸钠.本文报导该药剂对比目前国内工业循环冷却水常用的5种杀生剂对水土中常见的细菌、霉菌以及工业循环冷却水中主要危害菌、藻的抑杀效果。     

异噻唑酮用作循环冷却水杀菌灭藻剂的研究

本试验采用杯碟法、试管稀释法和显微直接计数法测试异噻唑酮对常见菌藻的抑杀效果,并用该药剂对循环冷却水主要危害菌——硫酸盐还原菌,铁细菌和形成粘液的异养菌进行室内静态杀菌试验。结果表明,其杀菌灭藻效果优于目前常用的工业杀菌剂,投药量10ppm,对水中主要危害菌的杀灭率达到99%以上。     

经济杀菌灭藻剂OACL控制工业循环水中有害微生物的研究

研究了经济杀菌灭藻剂OACL对异氧菌、硫酸盐还原菌和铁细菌的杀菌作用。结果表明,在实验室条件下,其杀菌率平均为99％以上,在pH5和pH7时分别为97.8％和88％。而在现场投药试验条件下为92％以上。可以认为,OACL是一种新型的、经济的高效杀菌灭藻剂。     

应用季铵盐控制炼油厂循环水中菌藻危害的研究

在调查东方红炼油厂循环冷却水系统被腐蚀危害的基础上,针对主要危害微生物——铁细菌、硫酸盐还原菌和形成粘液的异养菌,从4 7种药剂中筛选出既能杀菌灭藻,又具有污垢剥离作用的高效低毒药剂季铵盐——十二烷基二甲基苄基氯化铵(muc)。经小试中试及采用高低剂量结合、间隔冲击式瞬间投加方法进行的生产性试验,表明其杀菌率达99％;污垢抑制率95％以上,冷却塔壁菌藻抑制率达99％;挂片腐蚀率1．6密耳／年。     

ROS在抗生素致死效应中的作用机制及其应用

日益严重的细菌抗药性已成为人类健康的重要威胁,而更加全面深入地了解抗生素杀菌机制可以帮助我们更好地应对细菌抗药性问题。研究表明,ROS在抗生素的杀菌过程中起重要作用,涉及细菌胞内复杂的生理反应。现总结ROS在抗生素杀菌过程中作用机制及应用方面的一些最新研究进展,以期为寻找新的方法增强现有抗生素杀菌效果及开发新型药物提供一个新的视角。     

绿脓杆菌对鲎素耐受性特点及耐受性机制的研究

【目的】为了探讨鲎素作为抗菌药物在临床使用中的安全性问题,通过鲎素连续增高浓度法对绿脓杆菌进行耐受性诱导,并对其耐受性机制进行初步研究,以期为鲎素的广泛应用提供理论依据。【方法】绿脓杆菌ATCC27853为试验菌株,通过连续增高浓度诱导法筛选抗药菌株,并通过抗药稳定性、交叉抗药性、抗药性代偿测定来探究其耐受性特点,通过对其胞外蛋白酶活性、生物膜形成、胞外多糖含量的变化来探讨其抗药性机制。【结果】通过连续增高鲎素浓度法对原始菌株进行30多代诱导后,绿脓杆菌ATCC27853对鲎素的MIC值逐渐增高,80多代时产生了明显抗药性。抗药菌株对丁胺卡那以及pexiganan、鲎素同源肽tachyplesin III、polyphemusin I均能产生不同程度的抗药性。在无药培养基中抗药菌株以更长的延滞期作为抗药性代偿,但在有药培养基中具有更短的延滞期和更大的生长速率。抗药菌株较原始菌株分泌的胞外蛋白酶活性增高,并能降低鲎素的抗菌活性。在同样条件下抗药菌株较原始菌株胞外多糖含量增高,更易形成生物膜。【结论】在长期选择压力下绿脓杆菌ATCC27853对鲎素能产生抗药性,其抗药性机制可能与生物膜形成、胞外蛋白酶失活鲎素有关。关于细菌对鲎素的抗药性机制,有待进一步研究。     

《细胞研究》:抗生素耐药性研究取得进展

<正>细菌的药物抗性是当今全球面临的主要公共健康威胁之一。抗药性相关的机制研究及对策已成为世界卫生组织和各国政府共同关注的问题。日前,中科院生物物理所张凯、赵永芳课题组合作,在抗生素耐药性研究领域取得进展,相关成果发布于《细胞研究》。细菌有多种形式的抗药机制,最普遍的一种机制是利用细胞膜上的多个药物外排泵,将抗生素外排出细胞。大肠杆菌MFS家族的多药物外排蛋白Mdf A是抗药机制研究中的范例,对该蛋白结构的解析有助于深入认识细菌的药物外排机制。张凯课题组成功解析了Mdf A-氯霉素以及     

循环水中影响十二烷基二甲基苄基氯化铵杀菌作用的因素

季胺盐在医学上作为清洁消毒剂早巳为人们所熟知,曾密切结合致病菌类做了影响其消毒杀菌效果因素的研究。然而关于工业循环冷却水系统中应用于控制腐蚀危害微生物有关影响因素,却很少见到报道。为了控制工业循环水中微生物造成的腐蚀危害,我们针对从循环水中分离的主要腐蚀危害菌——硫酸盐还原菌、铁细菌及形成粘液的异养菌,筛选到了高     

弗氏痢疾杆菌和大肠杆菌多重抗药因子的接合转移和抗药因子的消除

病原菌多重抗药性的研究在医学上有重要意义。发生抗药性突变的频率一般比较低,而通过抗药因子接合转移获得抗药性的频率较高,而且常常是多重抗药因子同时转移。这种转移可在种间和属间进行。抗药性的遗传因子是由染色体外的质体携带的。我们用痢疾杆菌的抗药性菌株进行了多重抗药因子接合转移和抗药因子消除的试验,结     

模拟自然选择条件下细菌抗药性的探究实验

基于细菌在抗生素培养基中抗药性逐渐增强的原理,通过模拟自然选择条件,将自然选择在较短的时间内还原出来,进而探究在自然选择条件下大肠杆菌和金黄色葡萄球菌的抗药性,以及培养条件改变时,细菌由抗药型转变为野生型的情况。本实验为沪科版高中《生命科学》必修3中"生物进化"人为创设选择情境提供了可操作的实验支持,也丰富了自然选择等相关内容的教学。     

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.