细菌稳定L型返祖性的研究

营养琼脂培养的白喉杆菌、葡萄球菌、伤寒杆菌及甲型副伤寒杆菌的稳定L型经硬琼脂,20%血清琼脂,血琼脂及12%,20%,30%明胶培养基传代培养或注射动物体内均不能返祖。但L型—细菌型接触培养具有促沙门氏菌L型返祖作用,可能同细菌型的某种“促返祖因子”传递给L型有关。     

伤寒杆菌和甲型副伤寒杆菌的稳定L型外膜蛋白和染色体DNA酶切研究

非高渗培养基传代培养的伤寒杆菌和甲型副伤寒杆菌的稳定L型丧失了主要外膜蛋白、特异性表面抗原和染色体DNA部分片段,保留了沙门氏菌共同的内部抗原和形成L型独特的表面抗原。提示伤寒杆菌和甲型副伤寒杆菌的稳定L型多种特性的丧失同其基因或主要外膜蛋白的缺失有关。     

沙门菌CWDMs乳酸脱氢酶同功酶的观察

采用聚丙烯酰胺凝胶电泳法检测伤寒杆菌和甲型副伤寒杆菌的ＣＷＤＭｓ及其宁代细菌型和伤寒杆菌粗糙型的乳酸脱氢酶（ＬＤＨ）同功酶,以了解沙门菌ＣＷＤＭｓ生物氧化的特点和机制,探讨ＣＷＤＭｓ变异的性质。结果表明,伤寒杆菌和甲型副伤寒杆菌的细菌型及伤寒杆粗糙型在聚丙烯酰胺凝胶电泳后显示出相同的４种具有不同泳动速率的ＬＤＨ同功酶,但ＣＷＤＭｓ仅显示２种ＬＤＨ。ＣＷＤＭｓ的２种ＬＤＨ同功酶与其亲代细菌型及伤寒杆     

121株甲型副伤寒病原菌的噬菌体型和脉冲场凝胶电泳型

目的认识甲型副伤寒疫病区甲型副伤寒沙门菌的噬菌体型和脉冲场凝胶电泳（PFGE）型,确定噬菌体型和PFGE型之间的关系以及菌型的分布和流行率。方法采用沙门菌组合噬菌体和SpeI、XbaI消化染色体DNA的PFGE对来自玉溪市7县（区）的121株甲型副伤寒菌进行分型。结果121株菌存在4个完全噬菌体型或1个噬菌体型;用SpeI或XbaI消化产物分别得出以SpeI01、SpeI02或XbaI01占优势的5种或4种PFGE型,SpeI01型和SpeI02型分别占37．2％和57．9％,XbaI01型占95．1％。结论121株菌的噬菌体型与PFGE型之间无一致性联系,PFGE型的SpeI01和SpeI02或XbaI01是玉溪地区的主要流行型,采用SpeI和XbaI的PFGE是鉴别甲型副伤寒菌流行克隆的一项有用技术。     

沙门菌CWDMs苹果酸脱氢酶的检测

目的：了解沙门菌细菌壁缺陷突变株（CWDMs）的生物氧化及遗传特点和探讨细菌壁缺陷变异的性质与机制。方法：采用PAGE电泳法和分光光度法检测伤寒沙门菌和甲型副伤寒沙门菌及其CWDMs和伤寒沙门菌粗糙型和苹果酸脱氢酶（MDH）同工酶的活性与类型。结果：伤寒沙门菌和甲型副伤寒沙门菌的细菌型和伤寒沙门菌粗糙型经PAGE电泳可见一条MDH同工酶带,CWDMs电泳后可见两条MDH同Ⅰ酶带,在CWDMs的MDH中有一条泳动速率与细菌型及粗糙型的相同,另一条则较快。分光光度法检测证实。细菌型与粗糙型的MDH活性相似,CWDMs的MDH活性则明显较低。结论：CWDMs保留了与亲代细菌型一致的MDH和形成了一种新的MDH,并且其MDH的活性已显著降低,此特性可能与CWDMs生物氧化特性的改变有关。     

沙门菌CWDMs脂代谢检测

采用毛地黄皂苷敏感试验和菌细胞胆固醇、甘油三脂及胆碱酯酶定性与定量分析法,检测伤寒杆菌和甲型副伤寒杆菌经L 型变异后形成的细胞壁缺陷突变株(CW DM )的脂类代谢活性,了解这些CW DM 变异的性质和探讨细菌细胞壁缺陷突变与细菌演变的关系。结果表明,沙门菌CW DM s 具有显著的胆固醇和甘油三脂代谢活性、对毛地黄皂苷高度敏感并且还具有与白色念珠菌相似的胆固醇和甘油三脂的含量,但未能检出胆碱酯酶活性。CW DM s返祖菌丧失了脂类代谢酶类和胞浆膜不含胆固醇,恢复了与其亲代细菌型相似的代谢特征。提示在沙门菌天然即存在有与脂类及胆固醇代谢相关的基因,细胞壁的缺陷导致这些脂类及胆固醇代谢基因活化,以致 CW DM s 能够表达固醇和甘油三脂代谢活性和胞浆膜含有胆固醇     

伤寒杆菌在高渗营养液中变异L型

本文就伤寒杆菌接种于高渗营养液中观察,发现瓶底有沉淀,壁有颗粒粘附。将沉淀物接种血平板,L型平板培养,作涂片染色见颗粒状细菌,经5代返祖恢复原菌状态,经生化鉴定,血清试验证实为     

单份血清肥达凝集试验在甲型副伤寒诊断中的价值

目的：评价疑似甲型副伤寒病例单份血清肥达凝集试验(WAT)的诊断价值。方法：以甲型副伤寒沙门菌血培养阳性和／或血清鞭毛特异性抗原阳性的甲型副伤寒病例(n=76)、血培养阴性和／或血清抗原阴性的对照发热病人(n=92)和健康饮食从业人员(n=63)为检测对象,用WAT测定以上三种人群血清甲型副伤寒沙门菌O、H、A抗体,分析评价不同O、H、A判断值诊断甲型副伤寒的敏感性、特异性、阳性预测值和阳性似然比等指标。结果：获得三种人群O、H、A凝集价的分布及其几何平均滴度,20％对照发热病人O抗体效价≥160,而健康从业人员仅有3．2％的O抗体效价≥160,对照发热病人和健康人相应H抗体效价分别占17％和4．8％,A抗体效价分别占16％和1．6％。53％血培养阳性和血清鞭毛抗原阳性甲型副份寒病例O抗体效价≥160,相应H、A抗体效价分别占41％和51％。用敏感性、特异性、阳性预测值、阳性似然比等指标评价单份血清WAT诊断甲型副伤寒的价值,提出O或H或A≥160和O≥160或A≥80可作为WAT辅助诊断甲型副伤寒的标准。结论：单份血清WAT有助于甲型副伤寒的诊断,该试验对血培养阴性的临床疑似甲型副伤寒病例及其高危人群中甲型副伤寒病例的诊断有实用意义。     

6种沙门菌单克隆抗体的制备和效能评价

目的：制备稳定、特异、高亲和性的分别针对甲型副伤寒沙门菌、乙型副伤寒沙门菌、丙型副伤寒沙门菌、肠炎沙门菌、伤寒沙门菌和猪霍乱沙门菌的单克隆抗体。方法：用甲醛灭活的菌液抗原免疫BALB／c小鼠,取脾细胞与SP2／0骨髓瘤细胞融合;用灭活的菌液包被酶标板,ELISA筛选阳性克隆株,建立细胞系;选取高效分泌杂交瘤细胞,常规制备腹水并纯化,进行单抗特异性与亲和性评价。结果：筛选得到分泌6种沙门菌相应单克隆抗体的杂交瘤细胞株,获得高亲和性单抗;所有单抗与大部分病原菌（包括7种沙门菌、3株志贺菌、2株李斯特菌、4株致病性大肠杆菌、2株霍乱弧菌）无交叉反应,但由于同类型O抗原的广泛分布,抗乙型副伤寒沙门菌单抗与鼠伤寒沙门菌、抗伤寒沙门菌单抗与肠炎沙门菌有明显的交叉反应。结论：沙门菌单抗的制备,为感染性腹泻的监测、诊断奠定了基础。     

应用单克隆抗体鉴定光滑型布氏杆菌A和M位点的分布

<正> 检查了有毒和无毒布氏菌的表面大分子脂肪、蛋白质、肽聚糖以及脂多糖(LPSs)的含量和结构,光滑型菌种之间的主要区别在于表面的脂多糖部份.已发现光滑型布氏杆菌含有A和M两种不同抗原.在光滑布氏菌株中,两种抗原的相关量不同,而在粗糙型菌株中缺乏。在牛种布氏菌2208、19和1119株中发现了A-LPS。在羊种布氏菌16M和15M株中发现了M-LPS。而牛种Ⅳ,猪种Ⅳ的A和M-LPS两者的量几乎相等。     

伤寒沙门菌与甲、乙、丙副伤寒沙门菌质控血清的制备

应用免疫学原理,将伤寒沙门菌O901、H901和甲、乙、丙型副伤寒沙门菌分别制成全菌体抗原,免疫实验兔获取免疫血清。依据伤寒沙门菌和副伤寒沙门菌的抗原成分的异同性,选择适当的吸收菌除去免疫血清中的交叉反应抗体和类属凝集素,而保留其特异性的抗体。通过对诊断菌液的验证试验,证实吸收充分的免疫血清具有质控血清的特性。具备可靠性能的质控血清,适用于伤寒沙门菌与副伤寒沙门菌的菌种检定及其效价检测;亦有利于肥达氏诊断菌液的质量控制。     

Genetic Basis of Vi Antigen Expression in Salmonella paratyphi C

Analysis of hybrids formed in a cross between a Salmonella paratyphi C Hfr and an S. typhimurium recipient indicated that the structural genetic determinants of the S. paratyphi C Vi antigen are located closely adjacent to the mel determinant, between this marker and purA. A similar location was indicated for the structural genetic determinants of the S. typhi Vi antigen (the viaB locus) by the results of a mating in which a hybrid S. typhimurium Hfr bearing the S. typhi viaB determinants was used to transfer these genes to an S. typhimurium recipient. Mating experiments with a Vi-antigen-expressing S. typhi Hfr and an S. typhimurium hybrid recipient expressing the Vi antigen of S. paratyphi C yielded no recombinants in which loss of Vi antigen expression occurred, indicating that the chromosomal locus occupied by the genetic determinants of the S. paratyphi C Vi antigen is the same one at which, in S. typhi, the viaB genes reside. Introduction of a mutant S. typhi viaA gene into an S. typhimurium hybrid expressing the Vi antigen, as the consequence of prior receipt of the S. paratyphi C viaB determinants, resulted in that hybrid's loss of Vi antigen expression, demonstrating that the viaA determinant plays a role in Vi antigen expression in S. paratyphi C, as well as in S. typhi. Although the percentages of coinheritance of the viaB and mel determinants in the mating experiments suggested that their linkage is sufficiently close to allow cotransduction by P22, attempts to accomplish this with lysates prepared on S. typhimurium hybrids expressing either S. typhi or S. paratyphi C viaB determinants were not successful.     

O-antigen variation in Salmonella spp.: rfb gene clusters of three strains.

The O antigens of Salmonella serogroups A, B, and D differ structurally in their side-chain sugar residue. These genes encoding O-antigen biosynthesis are clustered in the rfb operon. We report here the molecular cloning and analysis of the rfb operons of Salmonella paratyphi A (serogroup A) and S. typhi (serogroup D). The regions of DNA nonhomology between the rfb operons of these serogroup A, B, and D representatives are identified, and the evolutionary derivation of serogroup A from a serogroup D progenitor is discussed.     

Bafoudiosbulbins A, and B, two anti-salmonellal clerodane diterpenoids from Dioscorea bulbifera L. var sativa

Two clerodane diterpenoids, Bafoudiosbulbins A 1, and B 2, together with five known compounds: tetracosanoic acid, 1-(tetracosanoyl)-glycerol, trans-tetracosanylferulate, beta-sitosterol and 3-O-beta-D-glucopyranosyl-beta-sitosterol were isolated from the tubers of Dioscorea bulbifera L. var sativa. Their structures were established by spectroscopic methods (1D and 2D-NMR, MS) and X-ray crystallographic diffraction analysis of compound 1. The CH2Cl2-soluble portion of the crude extract and the two clerodanes were screened for anti-bacterial activity using both agar diffusion and broth dilution techniques against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella typhi, Salmonella paratyphi A and Salmonella paratyphi B. They both showed significant activities against P. aeruginosa, S. typhi, S. paratyphi A and S. paratyphi B.     

A study of enteropathogenic organisms isolated in the public health laboratory, Lusaka.

A total of 328 specimens of stools were examined in the Public Health Laboratory during January and February 1973. Enteropathogens were isolated from 117 of these specimens. Besides these, 12 strains of Salmonellae were isolated from blood and 8 from urine. An occasional Salmonella was isolated from the pleural fluid (S. paratyphi A) pus from the knee (S. enteritidis) and from the C.S.F. of an infant (S. paratyphi C.). Salmonella typhi and Salmonella paratyphi A are the predominant Salmonella species. No Salmonella paratyphi B has been isolated. Shigella, was isolated with slightly less frequency than Salmonella, and Shigella flexneriis was the predominant species. E. coli 0112/K66 is the most common enteropathogenic E. coli. The majority of the Shigella and Salmonella species are sensitive to the common antibiotics used. The E. coli organisms show multiple resistance to a number of antibiotics.     

IgA-driven T cell-mediated anti-bacterial immunity in man after live oral Ty 21a vaccine

Cellular immunity against Salmonella typhi was observed by using a direct anti-bacterial in vitro assay in volunteers orally vaccinated with the live S. typhi mutant strain Ty 21a. With this experimental approach, it was demonstrated that Ty 21a vaccine also induces cellular immunity against S. paratyphi A and B. Interestingly, the mechanism involved in cellular immunity against bacteria seems to be of an antibody-dependent cellular cytotoxicity (ADCC) type, with IgA acting as the humoral arm and CD4+ T lymphocytes as the cellular one. In accordance with the increase in IgA-driven ADCC against S. typhi, a major rise in IgA against O and H antigens was observed in the serum of vaccinees in parallel to an increase in IgG of identical specificity. Furthermore, a Ty 21 vaccine induced cellular activity against flagellar antigens. These results indicate that IgA-ADCC by T lymphocytes against bacteria can originate from local stimulation of the gut mucosal immune system. This cellular defense mechanism might be at the origin of the protection induced by Ty 21a vaccine.