共查询到20条相似文献,搜索用时 78 毫秒
1.
抗生素通过干扰或抑制微生物的某一代谢环节,抑制微生物的生长或致死,抗生素耐药性的出现已成为治疗传染性疾病的最大障碍,不同抗生素,其耐药性机理各不相同,本文就几类常见抗生素耐药性的产生机理及传递作了简要综述。 相似文献
2.
3.
马凤森 《生物化学与生物物理进展》1987,14(4):31-38
微生物的某些多肽抗生素,以及肽聚糖的交联肽等在合成途径和氨基酸组成、结合方式上都与动物活性多肽不同。它们不象动物多肽那样首先由核糖体合成出其前体,然后经酶促裂解形成,而是直接由各自的多酶体系控制合成。其合成不被嘌呤霉素、链霉素等抑制,也不为核酸酶的处理所终止。负责肽抗生素合成的酶系的各组分,彼此间有严格的空间结构和功能的联系。与核糖体合成蛋白质相比,酶控制的肽合成的精确性较差。 相似文献
4.
《中国实验动物学报》2017,(6)
肠道菌群在哺乳动物及人类健康的作用正日益受到重视。仔猪的健康生长需要一个动态平衡的肠道微生态环境。然而,在猪的生命周期中,从食管到直肠的微生物分布与组成存在时间和空间的变化。健康的肠道菌群具有促进猪的营养代谢,维持肠黏膜屏障,调节免疫应答,抑制病原菌感染等功能。多种因素对猪肠道菌群的形成与稳定具有重要的作用,包括分娩方式(经过产道或剖宫产)、幼龄时期饮食(母乳或配方饲料)、抗生素或抗生素样分子的使用等。本文主要从仔猪肠道微生物组成与定植、功能、影响肠道微生物的因素等方面论述了仔猪肠道微生物与仔猪肠道健康的关系,从而加深肠道微生物对维护仔猪肠道健康作用的认识。 相似文献
5.
《中国科学:生命科学》2016,(10)
阿尔茨海默病是一种常见的中枢神经系统退行性疾病,主要表现为认知功能损伤.肠道微生物通过微生物-肠-脑轴调节宿主大脑功能和行为,包括认知行为.宿主的无菌状态、抗生素干扰、益生菌干预、饮食习惯等都会影响肠道微生物的组成和肠道的生理功能,同时也会影响宿主的认知行为,增加或降低宿主患阿尔茨海默病的风险.肠道微生物的紊乱导致的肠道通透性和血脑屏障通透性增加会增加神经退行性病变的发生.肠道微生物的代谢产物及其对宿主神经生化的影响会增加或降低阿尔茨海默病的风险.病原微生物的感染也会增加阿尔茨海默病的风险,同时,阿尔茨海默病的发病也支持"卫生假说",这些结果都提示阿尔茨海默病可能起源于肠道,与肠道微生物的紊乱密切相关.通过个性化的饮食定制或有益微生物的干预调节肠道微生物的平衡或将成为治疗阿尔茨海默病的新方法. 相似文献
6.
7.
8.
几种微生物制剂和微藻在水产养殖中的应用 总被引:17,自引:1,他引:16
工厂化高密度养殖,需人工大量投喂饲料,饵料残余及水产动物的排泄物溶解于水中,对养殖水体造成污染,危害养殖对象的健康生长。对鱼虾疾病用药物防治只是暂时性手段,广谱抗生素杀死或抑制了敏感细菌而保留了耐药的致病菌,破坏或干扰了水体原有的正常微生物区系的生态平衡,更增加了养殖动物感染病菌的机会,抗生素在生物体内的残留,最终会对人体产生危害。微生物应用于水产养殖来改善水体生态环境,抑制杀死病原微生物,并可作为饲料添加剂,补充营养成分,改善养殖动物胃肠道有益菌群,达到生态防治的目的,使养殖生产良性发展,取得更好的经济效益、生态效益。本文对目前国内外较为普遍应用于水产养殖的几种微生物、微藻类在水处理、防治病原微生物和病害发生方面的应用情况和发展动态进行了分析。
相似文献
9.
抗生素AGPM生物合成途径的初步研究 总被引:5,自引:0,他引:5
采用前体添加实验法、静息细胞培养法以及酶抑制剂法对藤黄灰链霉菌中抗生素AG PM生物合成途径进行了初步探讨。研究表明能转化成聚酮合成所需活性前体的氨基酸如异亮氨酸、缬氨酸、蛋氨酸、谷氨酸等以及短链脂肪酸乙酸、丙酸、丁酸盐对抗生素AGPM合成均有明显促进作用 ;另外 ,在培养基中添加脂肪酸和聚酮生物合成途径的专一性抑制剂浅蓝菌素 (2 5μg mL)或脂肪酸合成抑制剂碘乙酰胺 (0 5mmol L)时 ,菌体生长不受影响 ,而抗生素AGPM合成受到强烈抑制 ,分别为对照的 35 3 %和 2 6 2 % ; 相似文献
10.
新型超级细菌NDM-1可能全球蔓延 总被引:1,自引:0,他引:1
胡虎 《基因组学与应用生物学》2010,29(4)
<正>抗生素由某些微生物在生活过程中产生的,对某些其它病原微生物具有抑制或杀灭作用的一类化学物质。它也是人类抵御细菌感染类疾病的主要武器。但最近研究人员已经发现一种名为新德里金属β内酰胺 相似文献
11.
12.
13.
Gladys O. Latunde‐Dada 《BioEssays : news and reviews in molecular, cellular and developmental biology》2009,31(12):1309-1317
Recent advances in research on iron metabolism have revealed the identity of a number of genes, signal transduction pathways, and proteins involved in iron regulation in mammals. The emerging paradigm is a coordination of homeostasis within a network of classical iron metabolic pathways and other cellular processes such as cell differentiation, growth, inflammation, immunity, and a host of physiologic and pathologic conditions. Iron, immunity, and infection are intricately linked and their regulation is fundamental to the survival of mammals. The mutual dependence on iron by the host and invading pathogenic organisms elicits competition for the element during infection. While the host maintains mechanisms to utilize iron for its own metabolism exclusively, pathogenic organisms are armed with a myriad of strategies to circumvent these measures. This review explores iron metabolism in mammalian host, defense mechanisms against pathogenic microbes and the competitive devices of microbes for access to iron. 相似文献
14.
The interaction between pathogenic microbes and their host is determined by survival strategies on both sides, including competition for essential nutrients. During evolution, pathogenic microbes developed ways to access certain nutrients from the host, which, by contrast, can be exploited by the host for defence by restricting the availability of these nutrients. In this article, we review ecological aspects of the host-pathogen relationship and describe examples for competitive nutrient usage. We also discuss the beneficial probiotic microbes of the mammalian gut, which influence their environment including inflammatory host responses, and how they might be supported by prebiotic diets. 相似文献
15.
Microbes exert a major impact on human health and disease by either promoting or disrupting homeostasis, in the latter instance leading to the development of infectious diseases. Such disparate outcomes are driven by the ever-evolving genetic diversity of microbes and the countervailing host responses that minimize their pathogenic impact. Host defense strategies that limit microbial pathogenicity include resistance mechanisms that exert a negative impact on microbes, and disease tolerance mechanisms that sustain host homeostasis without interfering directly with microbes. While genetically distinct, these host defense strategies are functionally integrated, via mechanisms that remain incompletely defined. Here, we explore the general principles via which host adaptive responses regulating iron (Fe) metabolism impact on resistance and disease tolerance to infection. 相似文献
16.
Davis W Cheng Hong Lin Yuri Takahashi M Andrew Walker Edwin L Civerolo Drake C Stenger 《BMC plant biology》2010,10(1):135
Background
Plant cytochrome P450 monooxygenases (CYP) mediate synthesis and metabolism of many physiologically important primary and secondary compounds that are related to plant defense against a range of pathogenic microbes and insects. To determine if cytochrome P450 monooxygenases are involved in defense response to Xylella fastidiosa (Xf) infection, we investigated expression and regulatory mechanisms of the cytochrome P450 monooxygenase CYP736B gene in both disease resistant and susceptible grapevines. 相似文献17.
Morschhäuser J Köhler G Ziebuhr W Blum-Oehler G Dobrindt U Hacker J 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2000,355(1397):695-704
Various genetic mechanisms including point mutations, genetic rearrangements and lateral gene transfer processes contribute to the evolution of microbes. Long-term processes leading to the development of new species or subspecies are termed macroevolution, and short-term developments, which occur during days or weeks, are considered as microevolution. Both processes, macro- and microevolution need horizontal gene transfer, which is particularly important for the development of pathogenic microorganisms. Plasmids, bacteriophages and so-called pathogenicity islands (PAIs) play a crucial role in the evolution of pathogens. During microevolution, genome variability of pathogenic microbes leads to new phenotypes, which play an important role in the acute development of an infectious disease. Infections due to Staphylococcus epidermidis, Candida albicans and Escherichia coli will be described with special emphasis on processes of microevolution. In contrast, the development of PAIs is a process involved in macroevolution. PAIs are especially important in processes leading to new pathotypes or even species. In this review, particular attention will be given to the fact that the evolution of pathogenic microbes can be considered as a specific example for microbial evolution in general. 相似文献
18.
连作障碍与根际微生态研究Ⅰ.根系分泌物及其生态效应 总被引:59,自引:7,他引:59
作物、蔬菜、果树以及苗木长期连作后,皆出现生长衰退和产量降低.许多研究结果表明,连作条件下土壤生态环境对植物生长有很大的影响,尤以植物残体与病原微生物的分解产物,对植物有致毒作用,并影响植物根系分泌物正常代谢,以致于发生自毒作用.本文围绕根系分泌物与根际微生态的相互关系,系统地介绍连作障碍条件下,影响根系分泌物的环境因素(土壤空气、湿度、养分与微生物)、活性物质(自身毒素、残体分解物、微生物产生毒素)、土壤病原菌等的根际效应,为深入研究根系分泌物与连作障碍的相互作用机制提供启示. 相似文献
19.
连作障碍与根际微生态研究 Ⅰ. 根系分泌物及其生态效应 总被引:1,自引:0,他引:1
作物、蔬菜、果树以及苗木长期连作后,皆出现生长衰退和产量降低。许多研究结果表明,连作条件下土壤生态环境对植物生长有很大的影响,尤以植物残体与病原微生物的分解产物,对植物有致毒作用,并影响植物根系分泌物正常代谢,以致于发生自毒作用。本文围绕根系分泌物与根际微生态的相互关系,系统地介绍连作障碍条件下,影响根系分泌物的环境因素(土壤空气、湿度、养分与微生物)、活性物质(自身毒素、残体分解物、微生物产生毒素)、土壤病原菌等的根际效应,为深入研究根系分泌物与连作障碍的相互作用机制提供启示。 相似文献
20.
Bacteria and fungi are ubiquitous in the near-surface atmosphere where they may impact on the surrounding environment and human health, especially in coastal megacities. However, the diversity, composition, and seasonal variations of these airborne microbes remain limited. This study investigated the airborne microbes of the near-surface atmosphere in coastal megacity Qingdao over one year. It was found that the sample in summer displayed the highest bacterial and fungal diversity, while sample in winter exhibited the lowest bacterial and fungal diversity. Proteobacteria was the dominating bacteria, and Dothideomycetes was the most dominating fungi in the near-surface atmosphere, which took up 53–76 and 49–78% relative abundance, respectively. However, the bacterial diversity and community composition had significant seasonal variations. These data suggest that a complex set of environmental factors, including landscaping ratio, solar radiation temperature, and marine microorganisms, can affect the composition of airborne microbes in the near-surface atmosphere in coastal megacity. The analysis of the pathogenic microorganisms or opportunistic pathogenic microorganisms existed in the near-surface atmosphere revealed that the relative abundance of pathogenic microorganisms in autumn was the highest. The main pathogenic microorganisms or opportunistic pathogenic microorganisms were Acinetobacter baumannii (accounting for up to 9.93% relative abundance), Staphylococcus epidermidis (accounting for up to 11.26% relative abundance), Mycobacterium smegmatis (accounting for up to 3.68% relative abundance), Xanthomonas oryzae pv. oryzae (accounting for up to 5.36% relative abundance), which may be related to certain human or plant diseases in specific environments or at certain seasons. Therefore, the investigation of airborne microbial communities of near-surface atmosphere in coastal megacities is very important to both the understanding of airborne microbes and public health. 相似文献