细菌黏附素研究进展

黏附素是细菌表面某种特定的蛋白质结构或糖脂成分,可存在于细菌的细胞壁、外膜蛋白、鞭毛、菌毛及微毛等结构中。近年来关于细菌黏附素的研究取得了一些进展,笔者主要从细菌黏附素的发现、黏附现象及其机理、主要的一些细菌黏附素与黏附素受体、细菌黏附素研究的应用等方面作一综述。     

乳酸杆菌黏附人肠道上皮功能的研究进展

乳酸杆菌是人和动物肠道中重要的益生菌。益生菌进入肠道后,能够黏附定植并形成黏膜生物屏障,帮助肠道抵御各种致病菌的感染,维持肠道的正常功能。乳酸杆菌的黏附是由其表面蛋白、脂磷壁酸和胞外多糖等黏附素与宿主细胞表面的受体相结合的过程。为深入研究黏附机制,本文主要对乳酸杆菌黏附肠道上皮的黏附素和受体等方面进行综述。     

乳酸菌对动物肠黏膜黏附的相关因子及黏附机理

乳酸菌作为一种典型的益生菌,是肠道内的优势菌群,在改善肠道微生态环境、抑制肠道病原菌生长等方面具有重要作用。乳酸菌在宿主肠道中持久发挥生理功能的前提是能在宿主上皮细胞膜上发生黏附。因此,黏附性是乳酸菌发挥作用的功能性指标,也是当前研究的热点。本文就乳酸菌黏附的相关物质和黏附机理等方面进行综述。     

细菌鞭毛运动、黏附和免疫逃逸机制的研究进展

鞭毛是细菌表面重要的附属结构之一,很长一段时间以来被认为仅负责细菌的运动。然而随着对鞭毛的结构以及致病性深入研究发现,鞭毛的运动性能够促进细菌与宿主的相互作用,鞭毛介导的黏附在几种动植物病原体对宿主的定植过程中起很重要作用,而促进鞭毛结合到不同宿主组织的特异性互作机制至今仍不清楚。鞭毛素单体的保守区是机体先天性免疫应答的有效诱导剂,能够诱导机体发生免疫应答,然而细菌也进化出多重策略来逃避免疫识别。现对近年来细菌鞭毛在动植物宿主环境中的作用作一综述,为更全面认识和研究鞭毛提供参考。     

禽致病性大肠埃希菌黏附素研究进展

黏附素是具有黏附宿主细胞能力的细菌表面结构的统称,是直接介导细菌对宿主细胞黏附的物质,故又称定居因子(colonization factor)。在禽致病性大肠埃希菌侵袭宿主组织并引起宿主发病的过程中,黏附是病原菌接触和感染细胞的第一步,因此,黏附素黏附宿主上皮细胞并使宿主致病的作用机理引起了研究者的广泛关注。论文通过对禽致病性大肠埃希菌黏附素的组成成分、黏附机制、种类、分子生物学特性以及相应的黏附素受体等进行相关综述,为研究禽大肠杆菌病的发病机理及对该病进行免疫预防提供理论依据。     

奶牛乳房炎金黄色葡萄球菌黏附素研究进展

金黄色葡萄球菌的黏附素是其引起奶牛乳房炎的关键因素之一,与金黄色葡萄球菌在奶牛乳房中定植有关的的黏附素主要是ClfA、FnBPA和FnBPB3种。曾有对金黄色葡萄球菌黏附素表达调控的研究发现,在金黄色葡萄球菌感染的早期主要表达黏附素,之后才表达毒素和荚膜,所以人们认为,对金黄色葡萄球菌的黏附进行干预,可以减少或阻止毒素和荚膜的表达,而以黏附素作为靶位进行疫苗研制可能是预防奶牛金黄色葡萄球菌性乳房炎的有效途径。国外对金黄色葡萄球菌的黏附素的研究历史相对较久,并且也取得了许多可喜成绩,而国内对金黄色葡萄球菌的研究相对滞后。因此,研究金黄色葡萄球菌黏附素对预防由金黄色葡萄球菌引起的奶牛乳房炎具有广阔的前景。     

乳酸杆菌与肠道黏附相关表面因子及其机制的研究进展

乳酸杆菌为应用最早、研究最多的益生菌种之一.乳酸杆菌通过表面分子对肠道形成黏附和定植而发挥生理作用,包括养分消化吸收、排斥病原菌和调节免疫等.本文就乳酸杆菌表面蛋白(S层蛋白、引物酶sortase依赖蛋白、黏膜结合蛋白和胞外间质黏附的调节性表面蛋白)和非蛋白类黏附相关因子(脂磷壁酸和细胞外多糖)结构及其在黏附中作用的研...     

致仔猪腹泻产肠毒素大肠杆菌黏附素研究进展

黏附素(adhesion)是仔猪腹泻性大肠杆菌的一种毒力因子。大肠杆菌只有依靠黏附素黏附到小肠黏膜上皮细胞才能避免肠蠕动和肠液分泌对其的清除作用,并得以在肠内定居和繁殖,进而分泌肠毒素,导致腹泻。此文从黏附素主要类型、黏附素的表达条件、对肠黏膜黏附的特异性及其疫苗在仔猪腹泻防治中的应用等方面阐述了致仔猪腹泻的产肠毒素大肠杆菌最常见的几种黏附素的研究概况。     

乳酸菌细菌素应用研究进展

乳酸菌发酵过程中的代谢产物包括有机酸和细菌素。其中细菌素作为生物保护剂在食品中的应用得到广泛研究，对改善风味有一定贡献，此外细茵素在控制乳腺癌和生物医药中都展示了其应用潜能。随着分子生物学的发展，细菌素在基因工程的研究也取得一定的进展。     

Absence of bacterial adherence in the establishment of experimental mastitis in mice.

The possibility of adherence of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli or Streptococcus agalactiae to the epithelium of the mammary gland was investigated by inoculating them into this gland of mice. S. aureus, S. epidermidis and E. coli did not adhere to alveolar epithelium in suckling or non-suckling mice. S. agalactiae adhered to alveolar epithelium in non-suckling mice but adhesion was not sufficiently strong to withstand suckling. Bacterial adherence probably does not play a significant role in the establishment of mastitis by these organisms.     

Use of specific sugars to inhibit bacterial adherence to equine endometrium in vitro

OBJECTIVE: To determine whether specific sugars inhibit adhesion of Streptococcus zooepidemicus, Pseudomonas aeruginosa, and Escherichia coli to equine endometrial epithelial cells in vitro. SAMPLE POPULATION: Endometrial biopsy specimens collected during estrus from 7 healthy mares. PROCEDURE: Endometrial specimens on glass slides were incubated for 30 minutes at 4 C with suspensions of S. zooepidemicus, P. aeruginosa, or E. coli in phosphate-buffered saline solution (PBSS) alone or with various concentrations of D-(+)-mannose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, D-(+)-glucose, galactose, or N-acetyl-neuraminic acid. Inhibition of bacterial adherence was determined by comparing adhesion of bacteria (i.e., percentage of glandular epithelial cells with adherent bacteria) suspended in each sugar solution with that of bacteria suspended in PBSS. RESULTS: Mannose and N-acetyl-D-galactosamine inhibited adhesion of E. coli and P. aeruginosa to epithelial cells, whereas only mannose inhibited adhesion of S. zooepidemicus. The other sugars did not affect bacterial adherence. CONCLUSIONS AND CLINICAL RELEVANCE: Mannose and N-acetyl-D-galactosamine appear to play a role in adhesion of S. zooepidemicus, P. aeruginosa, and E. coli to equine endometrium. In horses with uterine infections, use of sugars to competitively displace bacteria from attachment sites on cells may provide an adjunct to antibiotic treatment.     

细菌对四环素类抗生素的耐药机制研究进展

四环素类药物为广谱抗生素,广泛用于临床治疗,并常被用做动物促生长剂,但耐药性的出现限制了该类药物的使用.四环素类药物产生耐药性的机制主要有核糖体保护作用、外输泵作用及产生钝化酶等.本文详细综述了其耐药机制的研究进展及耐药基因的发生率.     

Identification of bovine lymphocyte subpopulations by a combined bacterial adherence and fluorescent antibody technique

It is known that certain strains of bacteria bind selectively to subpopulations of human peripheral blood lymphocytes. We have developed a technique which used the specificity of bacterial binding concurrently with fluorescent antibody staining methods to identify 5 B-cell and 5 T-cell subpopulations of bovine lymphocytes. In addition, greater than 95% of the peripheral blood lymphocytes could be positively identified as being either T-cells or B cells. Using ethidium bromide-stained bacteria and lymphocytes in combination with fluorescent antibody staining to detect surface immunoglobulins or T-cell antigens, the method provided a simple yet highly specific technique for the enumeration of both B and T cells in 1 preparation of peripheral blood lymphocytes. The use of bacterial rosetting with fluorescent antibody staining was found to be easier and more reliable than the methods currently used to identify bovine B- and T-lymphocyte subpopulations.     

细菌细胞壁肽聚糖的研究进展

肽聚糖(PG)是细菌细胞壁成分, 大部分革兰氏阳性菌及部分革兰氏阴性菌细胞壁都含有PG.PG具有多种生物学活性,在调节宿主免疫功能方面发挥着重要作用.本文综述了细菌细胞壁PG的结构与分类、分离纯化、生物合成、代谢过程、生物学功能、免疫作用机制及应用前景.     

苜蓿杂种优势研究进展

对当前国内外苜蓿杂种优势的基础研究、遗传特性及优势形成机理进行了概述,并对其发展方向进行了初步展望,旨为苜蓿杂种优势利用的深入研究和高产优质苜蓿种质的创新提供参考。     

The occurrence of adherence factors in Enterobacteriaceae from bacteriological meat examination and from food hygiene research material

An account is given in this paper of the occurrence of 131 specific adherence factors (CFA 1a, CFA 1b, K88, K99) and 216 unspecific adherence factors (CT I) of Enterobacteriaceae strains from 917 bacteriological carcass inspection samples and of 23 or 87 identical strains recorded from 682 food hygiene samples. Identification was based on mannose-resistant and mannose-sensitive hemagglutination (MRHA and MSHA). Particular consideration was given to 3 aspects, occurrence of Escherichia coli adherence factors in bacteremic dissemination in bacteriological carcass inspection, parallel presence of additional virulence factors, and the hemagglutination spectrum of MSHA.     

超氧化物歧化酶（SOD）在蚕业上的研究进展

本文介绍了近年来桑和蚕ＳＯＤ研究的结果,阐明了它的生理作用。     

16S rRNA/rDNA序列分析技术在瘤胃细菌微生态系统研究中的应用

作者指出了反刍动物瘤胃细菌微生态系统研究的难点，介绍了细菌分类学中新兴的分子生物学指标（16S rRNA/rDNA序列同源性），综述了16S rRNA/rDNA序列分析中所采用的分子生物学方法和技术，并阐述了瘤胃分子微生物学研究的流程。     

牛卵母细胞胞浆内单精子注射的研究进展

本文叙述了牛卵胞浆内单精子注射(intracytoplasmic sperm injection ICSI)的研究进展。主要分析了前期处理精子对ICSI的影响,比较了各种激活处理对ICSI的提高效果,展望了ICSI的应用前景。