鼠伤寒少门氏菌粘附素样糖蛋白的分离与鉴定

鼠伤寒沙门氏菌用沙污剂NP－40处理，获得细菌外增溶液，经ConA-Sepharose4B亲和层析，甘露糖洗脱，得到了ConA结合糖蛋白，SDS－PAGE电泳显示出了5条蛋白带，分子量在15－43kD之间。用不同处理并借助扫描电镜观察细菌在雏鸡肠上皮的粘附情况，表明分离的ConA结合糖蛋白具有粘附素样作用，肠粘膜表面含乙酰氨基葡萄糖的糖复合物则可能是粘附素的受体。     

乳铁素参与乳房链球菌对乳腺上皮细胞的粘附

免疫印迹试验表明，试验用的3株乳房链球菌（Streptococcus uberis)菌株均可与乳铁素（Lactoferrin)结合。培养基中加入乳铁素或乳清可以显著促进细菌与乳腺上皮细胞之间的粘附，抗乳铁素抗体可以特异性地抑制乳铁素或乳清预处理细菌与乳腺上皮细胞的粘附。乳铁素在细菌和细胞之间起着桥梁分子作用。有助于细菌与乳腺上皮细胞之间的粘附和乳腺感染的建立。     

细菌的粘附与粘附素

细菌的粘附与粘附素潘玲吴信法（安徽农业大学２３００３６）众所周知，微生物必须先通过附着或粘附才有可能在宿主定居，进而感染，引起机体发病。对机体来说，外界的细菌必须接触动物的皮肤与粘膜，粘附定居，增殖或移位扩散，才能使感染或传染成立。过去对病原菌的毒力...     

乳酸菌肠道表面的粘附机制与生物效应

益生菌通过定植粘附于肠道表面而对宿主发挥作用,粘附机制迄今仍未明确,随着研究的深入,乳酸菌粘附的宿主特异性与非特异性学说和肠道上皮细胞粘附受体与乳酸菌表面分子粘附学说已成为主流学说。粘附过程中,需要粘附物质与宿主糖蛋白等粘附受体结合,粘附物质目前主流学说为脂磷壁酸学说、粘附蛋白学说、细菌表面分子学说。粘附效应的形成受到pH、温度、Ca2+、乳酸菌粘附数量、金属离子、粘附时间等因素影响,保护被粘附宿主细胞形态完整与生物屏障等生物学效应,对外籍菌起到占位抑制作用。     

禽大肠杆菌菌毛粘附特性的研究

用透射电镜观察了鸡大肠杆菌的３个致病菌株ＧＬ７（Ｏ５０）、ＨＢ５（Ｏ７８）及ＴＧ１８（Ｏ８８），发现在营养肉汤中于３７℃培养均表达菌毛，但在１８℃培养不表达菌毛，用３７℃培养的大肠杆菌对鸡气管粘膜做粘附试验，并用扫描电镜观察，发现它们对体内体外的鸡气管均可粘附，但１８℃培养的大肠杆菌均缺乏这种粘附作用。采用粘附抑制试验测定这３种菌株对体外鸡气管节段粘附的特异性，结果是抗这３种细菌菌毛的抗体能显著抑制各自相应的菌株对气管上皮的粘附；Ｏ７８株和Ｏ８８株对气管上皮的粘附作用可被甘露糖显著抑制，表明甘露糖对介导菌体对气管粘膜上皮细胞受体起重作用。用甘露糖不能抑制Ｏ５０菌株对气管上皮的粘着，表明该菌体的粘附作用不由甘露糖介导。用高碘酸钠处理能抑制所有菌株的粘附作用，再次表明细菌对气管上皮的粘附作用是由单糖介导的     

大肠杆菌K99纤毛抗原的提纯和抗血清制备

在引起初生犊牛、羔羊和仔猪腹泻的肠毒素大肠杆菌中,K99是常见的粘附素,这些细菌表面纤毛能与小肠黏膜上皮细胞表面的特异性受体位点结合,使细菌吸附于肠黏膜表面并产生肠毒素,导致急性腹泻、脱水,最后衰竭死亡.     

抗奶牛乳房炎金黄色葡萄球菌-细菌素的筛选及特性研究

奶牛乳房炎时常危害奶牛群，给奶牛养殖业造成严重的经济损失。在所有细菌性乳房炎中，金黄色葡萄球菌性奶牛乳房炎占比极高。本研究以金黄色葡萄球菌为指示菌，采用琼脂扩散法进行抑菌试验，从内蒙古手工奶酪中筛选到一株产细菌素的乳酸菌作为研究对象。根据形态特征，结合16S rRNA序列结果分析，鉴定菌株为Lacticaseibacillus saniviri，命名为LS-1。通过酶稳定性试验、酸碱稳定性试验、热稳定性试验，确定菌株LS-1的细菌素生物学特性。LS-1细菌素对木瓜蛋白酶、胃蛋白酶较敏感，经100℃水浴处理具有良好抑菌活性。LS-1细菌素经p H处理，p H为11.0时抑菌活性丧失。本研究所筛选的LS-1，丰富了产细菌素的菌种资源，其所产细菌素具有作为治疗奶牛乳房炎替抗产品的潜力。     

植物乳杆菌ST-Ⅲ粘附肠上皮样细胞系Caco-2性质的研究

选取肠上皮细胞Caco-2为体外模型,研究动力学因素和外在环境因素对ST-Ⅲ粘附效果的影响.结果发现ST-Ⅲ对Caco-2细胞的粘附在一定浓度和时间范围内存在量效关系.当加入细菌浓度达到4x108 CFU/mL、孵育2h时,粘附趋于饱和.稳定期的ST-Ⅲ对Caco-2细胞的粘附效果最好,推测与稳定期粘附素或相关物质的合成量最多有关.在外在环境对粘附效果的影响中,pH值对于粘附作用具有显著影响(P＜0.05),在中性范围粘附性最强;随着加入甲基-α-D-甘露糖苷浓度的升高,粘附的ST-Ⅲ数目显著下降(P＜0.05),当加入量大于100μmol/L,抑制作用趋于平缓;Ca2 、Mg2 并没有参与到ST-Ⅲ对Caco-2细胞的粘附中.实验结果表明,ST-Ⅲ对Caco-2细胞的粘附是多种因素共同作用的结果,其中粘附素与受体的结合占主导地位.     

喷雾干燥细菌素的生物学活性研究

为了初步研究前期试验筛选获得的枯草芽孢杆菌产细菌素的生物学活性,本试验采用杯碟扩散法绘制出硫酸黏杆菌素和杆菌肽锌两种抗生素的抑菌效价标准曲线,用抗生素效价当量来评价细菌素的活性,并在不同温度处理下测定其抗菌活性和热稳定性。结果表明,125 mg/mL细菌素溶液抑菌效价与26 mg/mL硫酸黏杆菌素或11.9 mg/mL杆菌肽锌溶液相当。此外,该细菌素在高温条件下(60~80 ℃)处理15 min仍能维持较高抑菌活性。综上所述,本试验在细菌素和抗生素的抑菌活力之间建立了更直观的联系,并证明了该细菌素具有较好的热稳定特性,为其产业化推广提供了理论支持和技术借鉴。     

糖原组学——家禽营养中的一个崭新的前沿科学

很多肠道病原菌可借助于特定甘露糖粘附素（细菌细胞表面的凝集素）而黏附到肠道上皮上。[编者按]     

Association of Streptococcus gallolyticus strains of high and low virulence with the intestinal tract of pigeons

We investigated the ability of a high virulence (STR 357) and a low virulence (STR 598) strain of Streptococcus gallolyticus to attach to the intestinal tract of pigeons. For that purpose, first of all, two groups of six pigeons were anesthetized and ligatures were placed at the beginning of duodenum, jejunum, ileum, and colon. The obtained intestinal loops of the birds of the first and second group were injected with S. gallolyticus strains STR 357 and STR 598, respectively. At 15, 30, and 60 min postinoculation, two pigeons of each group were euthanatized and the various intestinal loops were sampled for histologic, immunohistochemical, and electron microscopic examination. Both the high and low virulence strains were able to adhere to the intestinal mucosa. Indeed, all samples dearly showed numerous coccal-shaped bacteria that stained positively with S. gallolyticus antiserum and were lining up against the intestinal epithelium. Likewise, on electron microscopic examination, cocci were seen in the mucus covering the intestinal epithelium. Second, the association of S. gallyticus strains of differing virulence with the intestinal tissue was determined quantitatively. Experiments were performed as described above. The number of S. gallolyticus bacteria that adhered to the intestinal epithelium was determined by plating out 10-fold serial dilutions of the segments. No significant differences in the number of adhered bacteria were found between the strains of high and low virulence.     

In vitro adhesion of an avian pathogenic Escherichia coli O78 strain to surfaces of the chicken intestinal tract and to ileal mucus

The role of fimbria in adherence of an avian pathogenic Escherichia coli (APEC) O78 strain 789 to chicken intestine was studied. Bacterial adhesion to tissue sections representing the regions within the chicken intestinal tract was determined by using immunohistochemical methods. E. coli 789 grown to express the type 1 fimbria adhered efficiently to the crop epithelium, to the lamina propria of intestinal villi, and to the apical surfaces of both the mature as well as the crypt-located enterocytes in intestinal villi, whereas no adhesion to mucus-producing goblet cells was detected. The adhesion was inhibited by mannoside and the role of type 1 fimbriae in the observed adhesion was confirmed with a recombinant strain expressing type 1 fimbriae genes cloned from E. coli and Salmonella enterica. E. coli 789 strain grown to favor AC/I fimbriae expression as well as the recombinant E. coli strain expressing the fac genes adhered to goblet cells but only poorly to the other epithelial sites. E. coli strain 789 as well as S. enterica serovar Typhimurium IR715 and S. enterica serovar Enteriditis TN2 strains were able to multiply in ileal mucus medium. The type 1 fimbria expressing bacteria adhered to the ileal mucus, whereas the AC/I fimbriated strains showed poor adherence to the mucus. The adhesion of E. coli 789 onto the crop epithelium and the follicle associated epithelium of the chicken ileum was efficiently inhibited by an adhesive strain ST1 of Lactobacillus crispatus isolated from chicken, whereas poor inhibition of E. coli adherence was observed with the weakly adhesive L. crispatus strain 134mi. The type 1 fimbriae may be important in colonization of the chicken intestine by APEC and Salmonella.     

伪狂犬病病毒鄂A株gG^—／LacZ^＋突变株的构建

以从湖北某猪场分离鉴定的鄂A株为亲本，提取其基因组DNA，克隆含gG基因的SphI/KpnI片段，然后将LacZ基因融合到gG启动子下游，得到重组质粒pUSKZ,将重组质粒与鄂A株基因组共转染PK－15细胞，待细胞完全病变后，在X－gal存在下，作蓝斑筛选纯化。经斑点杂交和PCR扩增证实得到的是基因型为gG^-/LacZ^ 的重组伪狂犬病病毒。     

华蟾毒精对小鼠免疫细胞活性的影响

为观察华蟾毒精（CBG）对小鼠免疫细胞活性的影响,本研究采用MTT法检测小鼠脾淋巴细胞的增殖情况,检测小鼠腹腔巨噬细胞的吞噬功能以及小鼠NK细胞对靶细胞的杀伤作用。结果显示,CBG在一定剂量范围内单独或者协同非特异性丝裂原（Con A或LPS）作用能够显著增强小鼠脾淋巴细胞的增殖,CBG单独作用可以显著提高小鼠腹腔巨噬细胞的吞噬功能,并能够显著提高小鼠NK细胞对靶细胞的杀伤作用,表明CBG能够提高小鼠免疫细胞的活性。     

Population of Salmonella serovar typhimurium in the cecum of gnotobiotic chickens with Escherichia coli and intestinal bacteria.

To test the interaction between various species of bacteria and Salmonella serovar typhimurium (S. typhimurium), the population of S. typhimurium was measured in the cecum of gnotobiotic chickens in the presence of Escherichia coli (E. coli) and one of the four intestinal bacteria; Lactobacillus acidophilus. Clostridium perfringens, Bifidobacterium thermophilum and Bacteroides vulgatus. Competitive exclusion of S. typhimurium by di-flora chicken was not demonstrated. But the population of S. typhimurium was temporarily suppressed in di-flora chickens with E. coli and L. acidophilus. In penta-flora chickens with E. coli and these four intestinal bacteria, the population of S. typhimurium was suppressed for only 2 days. In normalized chickens, the population of S. typhimurium was markedly suppressed.     

The influence of whole wheat feeding on Salmonella infection and gut flora composition in broilers

In an experiment with broilers infected with a rifampicin-resistant Salmonella Typhimurium strain at 15 days of age, it was demonstrated that whole wheat feeding influenced the course of infection. The pH in the contents of the gizzard decreased as the amount of whole wheat in the diet increased over time. Following infection, lower numbers of Salmonella Typhimurium were found in the gizzard and ileum of birds receiving whole wheat compared to pellet-fed birds. However, there was no difference with respect to the numbers of Salmonella Typhimurium in the ceca and rectum between the two experimental groups. Quantitative cultivation of different groups of bacteria belonging to the natural intestinal microflora showed that whole wheat feeding significantly reduced the numbers of Clostridium perfringens in the intestinal tract of the birds. The present results indicate that the gizzard has an important function as a barrier organ, one that prevents pathogenic bacteria from entering the distal digestive tract.     

二氢吡啶对雏鸡血清甲状腺素和皮质醇含量影响的研究

为探求二氢吡啶促雏鸡生长发育的机理，试验分两批进行。（1）选用28日龄海赛克斯父母代母雏250只，随机分为5组，日粮中添加不同浓度的二氢吡啶。饲养试验表明二氢吡啶可促进雏鸡的生长，且以150mg／kg组促生长作用最佳，添加饲喂到61d时，体重比对照组提高7.68％（P＜0.01），血清中T     

Adhesion of bacteria to the cecal mucosal surface of conventional and germ-free chickens infected with Eimeria tenella.

When Salmonella typhimurium and Clostridium perfringens were tested in conventional chickens, larger numbers of S typhimurium and C perfringens adhered to Eimeria tenella-infected ceca than to uninfected ceca. In germ-free chickens, S typhimurium and C perfringens adhered to the E tenella-infected cecal mucosa more than to the uninfected cecal mucosa, but fewer Bacteroides vulgatus and Bifidobacterium thermophilum adhered to the E tenella-infected ceca than to the uninfected ceca. Many bacteria adhered to the lesions caused by E tenella as observed by scanning electron microscopy. On the basis of our findings, we suggest that infection with E tenella upsets the balance of competitive adherence of bacteria, allowing more colonization of S typhimurium and C perfringens.     

大熊猫慢性胃肠炎病研究

本文分析了9例大熊猫慢性胃肠炎病及其继发病的发病机理和发病特点，采用中西医结合标本兼治的治疗方法，收到了较好效果。有5只完全恢复了健康，3只有明显疗效。并对患病大熊猎作了血液学检查，与健康大熊猫的肠道菌群、毛发微量元素的测试、分析比较，结果表明：患病大熊猫的电解质水平普遍偏低，血清蛋白较低，白细胞水平大多处于正常范围，在患慢性胃肠炎病大熊猫粪便中未检出肠道病原菌，其双歧杆菌的检出率和数量明显低于健康大熊猫。毛发中Cu、Zn、Mn等元素含量极显著低于健康大熊猫的水平，初步提出了大熊猫慢性胃肠炎病及其继发病的综合预防与治疗措施。     

Infection models for Salmonella typhimurium DT110 in day-old and 14-day-old broiler chickens kept in isolators

A series of experiments was undertaken to investigate the infection dynamics of various doses of S. typhimurium in day-old and 14-day-old broiler chickens kept in isolators. The infections were followed quantitatively in ceca and ileum by enumerating the colony forming units (cfu) of the challenge strain. It was found that the inoculation of 10(7) cfu of S. typhimurium to day-old chickens established stable cecal infection in all the animals for 35 days. For 14-day-old chickens, stable and lasting infections were seen with inoculation of 10(9) cfu. Lower doses yielded more variable results, and the bacteria were rapidly eliminated from most birds, especially in 14-day-old inoculated chickens. Salmonella was found in spleen and liver 2-3 days postinoculation. Salmonella was cleared from both organs or reduced to very low numbers within 3 weeks.