鼻咽癌与细菌L型的关系

大量研究表明,鼻咽癌与ＥＢ病毒有关。通过对９８例鼻咽癌组织的切片革兰氏染色Ｌ型检查、电镜和Ｌ型抗体免疫组化染色等研究,发现鼻咽癌组织中细菌Ｌ型亦甚常见,切片革兰氏染色有７８例查见细菌Ｌ型,其阳性率为７９．６％;免疫细化染色Ｌ型抗原检出阳性率为６２．２％,电镜不仅在细胞间质见到细菌Ｌ型,而且在癌细胞、巨噬胞细等细胞胞质内也见到细菌Ｌ型。提示,细菌Ｌ型与鼻咽癌关系十分密切,很可能是鼻咽癌致癌因子之一。     

Comparison of PERV genomic locations between Asian and European pigs

Xenotransplantation from pigs provides a possible solution to the shortage of human organs for allotransplantation. Porcine endogenous retroviruses (PERVs) are a possible obstacle to using porcine organs in addition to the immunological barriers. Three main types of PERVs (A, B and C) have been previously investigated in diverse pig breeds. To examine the copy numbers of PERVs and their genomic locations in the Korean native pig genome, we screened a BAC (Bacterial Artificial Chromosome) library with PERV-specific protease primers for initial recognition of PERV-positive clones and three sets of envelope-specific primers for the identification of PERV types. A total of 45 PERV-positive clones, nine PERV-A and 36 PERV-B, have been identified from the library screening and the BAC contigs were constructed using the primers designed from BAC end sequences (BESs). These primers were also used for SCH (Somatic Cell Hybrid) and RH (Radiation Hybrid) mapping of the PERV-positive clones. The results indicate that 45 PERV-positive BAC clones belong to nine contigs and a singleton. SCH and IMpRH (INRA-Minnesota Porcine Radiation Hybrid) mapping results indicated that there are at least eight separate PERV genomic locations, consisting of three PERV-A and five PERV-B. One contig could not be mapped, and two contigs are closely located on SSC7. Southern blotting indicates there may be up to 15 additional sites. Further investigation of these clones will contribute to a general strategy to generate PERV-free lines of pigs suitable for xenotransplantation.     

高通量细菌鉴定方法研究进展

高通量细菌鉴定是微生物领域的重要研究课题,对于疾病诊断和环境监测具有重要意义。相比传统的表型鉴定方法,分子遗传学鉴定方法具有稳定性高、检测周期短以及成本较低等特点,成为了主流的鉴定方法。特别是下一代DNA测序技术、核酸分子检测基础上的细菌检测芯片、质谱技术基础上的蛋白质图谱分析为高通量、快速、准确乃至定量的细菌鉴定提供了可行性方案。     

Fermentation of starch hydrolysates byLactobacillus plantarum

Summary Lactic acid production by an isolated ofLactobacillus plantarum was standardised on enzyme-hydrolysed tapioca (Manihot esculenta) flour, tapioca starch and soluble starch. Calculated yields of lactic acid (g from 100 g reducing sugars used) in nutrient media containing the abovementioned hydrolysates (10% reducing sugars) were 21.8%, 16.2% and 16.2%, respectively. Higher yields (29–34%) were obtained in media containing 5% reducing sugars. A conversion efficiency of 80–99% was achieved when the acid produced in the broth was neutralised periodically. One hundred milliliters of the medium (5% sugars) yielded 4.0–4.5 g of calcium lactate. These results indicate that unrefined starchy material can be successfully employed for the economic production of lactic acid. The same substrate can also be utilised for biomass production, as viable lactobacilli are being used for therapy in medicine.     

Optimization of a phenol extraction‐based protein preparation method amenable to downstream 2DE and MALDI‐MS based analysis of bacterial proteomes

2DE is one of the most efficient and widely used methods for resolving complex protein mixtures. For efficient analysis of complex samples, high‐resolution separation of proteins on 2D gel is essential, and for that purpose good sample preparation is crucial. In this study, we have improvized a method for preparing bacterial total cellular proteome, from a strategy applied earlier to recalcitrant plant tissues, which gave high‐quality resolution on 2DE. The method involving phenol extraction followed by methanol/ammonium acetate precipitation was first optimized for the chemolithotrophic proteobacteria Tetrathiobacter kashmirensis WT001 and Pseudaminobacter salicylatoxidans KCT001 that did not yield quality protein preps in conventional trichloroacetic acid/acetone precipitation method. Subsequently, to validate its general applicability, the method was evaluated against the trichloroacetic acid/acetone precipitation method for two other model bacteria, i.e. Escherichia coli DH5α and Mycobacterium smegmatis mc²6. Identification of at least four proteins each from the outer membrane, periplasm, and cytoplasm of T. kashmirensis by MALDI‐MS not only proved the efficiency of the method in extracting proteins from the different cellular compartments but also the amenability of the obtained protein spots toward MALDI‐MS based identification.     

绝经前后细菌性阴道病厌氧菌群及耐药性分析

目的了解绝经前后细菌性阴道病患者标本中优势厌氧菌群,检测厌氧菌分离株对5-硝基咪唑类和林可霉素类抗生素的耐药性。方法采集165例未绝经和125例绝经阴道病患者以及84例未绝经和68例绝经正常妇女的阴道分泌物,测定其pH。采用选择性厌氧培养基分离类杆菌、梭杆菌、乳杆菌、优杆菌、消化链球菌和消化球菌,将分离的厌氧菌株鉴定至种。同时采用二倍平皿稀释法,测定塞克硝唑、替硝唑、甲硝唑、林可霉素和克林霉素对760株厌氧菌的最低抑菌浓度。结果100%细菌性阴道病患者、97.6%未绝经和98.5%绝经正常妇女的阴道分泌物中分离出厌氧菌。阴道炎患者标本中,类杆菌属、普氏菌属和紫质单胞菌属厌氧菌分离率高于相应对照组(P<0.05;P<0.01),其中以多毛类杆菌、腐败类杆菌、脆弱类杆菌、产黑普氏菌、不解糖紫质单胞菌为优势菌群;梭杆菌属、优杆菌属、消化球菌属和消化链球菌属厌氧菌分离率与相应对照组比较差异无显著性(P>0.05);乳杆菌属分离率明显低于相应对照组(P<0.01)。未绝经正常妇女和患者及绝经正常妇女和患者阴道分泌物pH分别为4.5±0.2、5.5±0.8、6.5±0.3和6.5±1.0。塞克硝唑、替硝唑和甲硝唑对355株革兰阴性厌氧菌M IC90值为1~8μg/m l,林可霉素和克林霉素则为4~16μg/m l;塞克硝唑、替硝唑和甲硝唑对405株革兰阳性厌氧菌M IC90值为8~32μg/m l,林可霉素和克林霉素则为4~16μg/m l。     

多点接种方法计数土壤细胞生理类群的研究

多点接点计数方法是根据细菌分解固体培养基上不同的有机化合物的能力确定为不同的生理类群,由有机化合物的降解点数和根据MPN方法进行计数,对不同的耕作方法进行了测定表明,秸秆覆盖免肾够明显提高土壤中分解淀粉,木聚糖,纤维素,果胶,几丁质,卵磷质,脂类和蛋白质类群的细菌数量。     

吩噻嗪衍生物在体内外对肠道细菌的作用

本工作测试了７种吩噻嗪衍生物在体外对５株好氧或兼性厌氧菌和８９株厌氧菌的最小抑菌浓度,结果表明,吩噻嗪衍生物对细菌（尤其是球菌和厌氧菌）具有一定的抑制作用,但携带可拮抗艰难梭菌肠道定植屏障菌群的悉生小鼠接受２周或４周的Ｃｈｌｏｒｐｒｏｍａｚｉｎｅ（０．２ｍｇ／小鼠／天）并不会使菌群屏障遭破坏。     

绿脓杆菌群集生长效应

本文通过群集的绿脓杆菌在高盐、酸性培养基上生长试验,抗金黄色葡萄球菌的拮抗试验及冷休克试验,证明了绿脓杆菌群集生长效应。主要表现为群集的绿脓杆菌可以在含10～20%NaCl 的培养基上生长;pH4环境中也可生长。同样条件下,对照几乎均为阴性。分散成单个细胞分布的绿脓杆菌对冷反应敏感,群集则有抗冷休克作用。实验条件下,密集的金黄色葡萄球菌生长对分散的绿脓杆菌有拮抗作用,群集则可抵抗这种作用而生长。讨论中初步分析了群集生长效应的机理和对细菌种群在自然生境中的稳定作用。     

噬菌体治疗细菌性感染及其限制因素

近年来,细菌耐药性已成为抗感染领域面临的严峻问题,临床对一些细菌性感染疾病束手无策。噬菌体疗法是一种通过噬菌体裂解细菌来治疗病原菌感染的治疗手段。噬菌体在抗菌领域表现出显著的优越性,成为目前治疗细菌性感染的研究热点。本文对近年来噬菌体治疗动物和人类病原菌感染、限制其临床应用的因素及解决措施进行综述。