泰泽氏病原体抗原表位相关肽的初步筛选与鉴定

目的获得泰泽氏病原体抗原表位相关肽,用于实验动物血清中该病原体感染相关抗体的检测。方法选用泰泽氏病原体的四种单克隆抗体(M2、M3、M4、M5)作为配基,从噬菌体表面展示的随机7肽文库中筛选单抗识别的抗原表位,获得特异性噬菌体克隆;并采用ELISA、Western blot方法对其进行分析鉴定,获得阳性噬菌体克隆。结果获得阳性噬菌体克隆5个,其展示的融合蛋白能被泰泽氏病原体的免疫血清识别,ELISA检测A值的P/N为8.0～17.1;Western blot分析显示单一特异性条带,相对分子质量约为38×103。结论本研究获得的5个阳性克隆所表达的融合蛋白,为泰泽氏病原体抗原表位相关肽,可作为该病原体隐性感染血清学检测的候选抗原。     

泰泽病原体基因组DNA提取方法的建立

目的　提取泰泽病原体基因组DNA ,为建立该菌基因组文库奠定基础。方法　使用密度梯度离心结合酶解消化方法、酶解消化方法、本研究建立方法即过滤盐析离心法 ,从感染肝脏组织纯化泰泽病原体 ,并比较三种方法纯化泰泽病原体效果 ;采用氯化苄法、试剂盒、酚法提取泰泽病原体基因组DNA ,并比较三种方法提取基因组DNA质量 ;鉴定酚法提取泰泽病原体基因组DNA特异性。结果　使用过滤盐析离心法从感染肝脏组织纯化泰泽病原体 ,采用酚法提取其基因组DNA ,所获得的基因组DNA特异性好、纯度高、DNA片段长度大于 5 0kb ,且均一性好 ,无降解。结论　本研究首次成功提取泰泽病原体基因组DNA ,可用于多种分子生物学实验     

一些主要致病菌简介(续一)

<正> 芽胞杆菌科菌体杆状,其中有一个属为球形。不产生菌丝,形成内生芽胞。芽胞与菌体不同,光反射性强,着色力差,耐热和抗破坏力强,芽胞干重的5-15％为胞壁酸(Dipicolinic acid)。芽胞位于菌体中央(核心),由葡萄糖肽组成的外层包围着,有芽胞外套。多为革兰氏阳性,能运动(侧毛或周毛菌)或不能运动,需气或兼性嫌气。芽肠杆菌科中属的提要1、菌体杆状A.需气或兼性嫌气,常产生过氧化氢酶。Ⅰ属、需氧芽胞杆菌属B.微嗜气菌,不产生过氧化氢酶。Ⅱ属、乳状芽胞杆菌属C.嫌气性。1.硫酸不还原为亚硫酸Ⅲ属、梭状芽胞杆菌属2.硫酸还原为亚硫酸     

柿叶黄酮对BSD-2菌株芽胞数量及抑菌活性的影响

研究PB液体培养基中加入不同浓度的柿叶黄酮对内生枯草芽胞杆菌生长、芽胞形成及抑菌活性的影响,利用光学显微镜观察菌体形态、稀释平板法统计芽胞数量、平板扩散法和病原菌生物测定的方法测定抑菌效果。结果表明,加入柿叶黄酮浓度为0.5%的处理对菌体生长无影响,使芽胞数量提高100倍,同时增强对灰霉、黑斑、黄萎病原菌的抑菌效果。     

小碎斑鱼蛉幼虫肠道细菌分离及鉴定研究

目的从微生态学角度研究小碎斑鱼蛉幼虫的营养生理活动。方法从小碎斑鱼蛉幼虫肠道环境中进行分离、纯化和培养,获得3个细菌菌株,对其菌体形态、染色反应、培养性状和生理生化反应进行系统研究。结果上述3个菌株均属于芽胞杆菌属(Bacillus),1号菌株为巨大芽胞杆菌(Bacillus megaterium),2号菌株为枯草芽胞杆菌(Bacillus subtilis),3号菌株为地衣芽胞杆菌(Bacillus licheniformis)。结论小碎斑鱼蛉幼虫肠道环境中的不同细菌,其数量存在明显差异。     

达乌尔鼠兔和布氏田鼠食物资源竞争关系的研究

布氏田鼠和达乌尔鼠兔是内蒙古典型草原的两种主要害鼠。本文研究了重叠分布于内蒙古克什克腾旗阿其乌拉境内克氏针茅+冷蒿+羊草草场上的布氏田鼠和达乌尔鼠兔的食物资源竞争关系。胃内容物显微组织学分析结果表明,夏季布氏田鼠取食羊草、杂花苜蓿、阿尔泰狗娃花等20种植物,而达乌尔鼠兔则选择羊草、菊叶委陵菜和杂花苜蓿等15种植物为食     

高原鼠兔肝中Ldh-c基因的表达及其对无氧糖酵解水平的影响

高原鼠兔(Ochotona curzoniac)对高原低氧环境有很强的适应性。我们研究发现,精子特异性乳酸脱氢酶(LDH-C4)在高原鼠兔肝组织中表达。为了阐明LDH-C4对高原鼠兔肝组织无氧糖酵解水平的影响,将20只高原鼠兔随机分为抑制剂组和空白对照组,每组10只。抑制剂组注射1 mol/L LDH-C4特异性抑制剂N-异丙基草氨酸盐(N-isopropyl oxamate)于高原鼠兔股二头肌,双侧各注射500μl,空白对照组注射等剂量的0.9%生理盐水。应用荧光定量PCR和western blot方法,测定了精子特异性乳酸脱氢酶基因(Ldh-c)在高原鼠兔肝组织中的表达水平,应用高压液相色谱法测定了血液中抑制剂的浓度,用生物化学方法测定了抑制剂组和空白对照组高原鼠兔肝组织中乳酸脱氢酶(LDH)比活力以及乳酸(LD)和ATP含量。结果表明,在m RNA和蛋白水平,Ldh-c基因在高原鼠兔肝组织中均有表达,m RNA相对表达水平为0.22±0.04,蛋白相对表达水平为0.97±0.20;当肌肉注射1 mol/L的抑制剂30 min后,血液中抑制剂浓度为0.08 mmol/L,肝组织中乳酸脱氢酶比活力抑制剂组和空白对照组分别为(4 990±290)U/g和(7 360±420)U/g,抑制剂组和空白对照组乳酸含量分别为(0.38±0.05)mmol/g和(0.53±0.03)mmol/g,抑制剂组和空白对照组ATP含量分别为(5.84±0.83)μmol/g和(7.78±1.06)μmol/g,经单因素方差分析,抑制剂组的乳酸脱氢酶比活力和乳酸及ATP含量均显著下降(P0.01);抑制剂对乳酸脱氢酶比活力和乳酸及ATP含量的抑制率分别为30.19%±3.90%、32.22%±8.70%和24.94%±7.80%。以上结果说明,Ldh-c在高原鼠兔肝组织中表达,LDH-C4通过催化无氧糖酵解过程,为其肝组织生命活动提供至少24%的ATP,这可能使高原鼠兔减小了在低氧环境中对氧气的依赖,增强了对低氧环境的适应力。     

不同品系小鼠对炭疽芽胞杆菌弱毒株芽胞的敏感性研究

通过比较四种品系小鼠对炭疽芽胞杆菌（Bacillus anthracis）（简称炭疽杆菌）弱毒株芽胞的敏感性，确定炭疽杆菌弱毒株芽胞攻毒合适的动物模型。采用炭疽杆菌弱毒株A16Q1（pXO1-、pXO2+）和A16PI2（pXO1+、pXO2-）的芽胞对四种品系小鼠（DBA/2、KM、ICR和BALB/c）进行腹腔攻毒，记录小鼠死亡时间，计算LD₅₀、绘制存活曲线并统计分析。运用较敏感的KM小鼠研究不同canSNP基因型毒素缺陷株（含pXO2拷贝数不同）芽胞的毒力差异。利用更为敏感的DBA/2小鼠评价S-层蛋白BA3338对荚膜缺陷株芽胞毒力的影响。结果表明，在四种品系小鼠中，毒素缺陷株芽胞的毒力均高于荚膜缺陷株芽胞的毒力。DBA/2小鼠对炭疽杆菌弱毒株芽胞的剂量依赖关系最好，最为敏感，其次是KM小鼠，而ICR小鼠和BALB/c小鼠对炭疽杆菌弱毒株芽胞不敏感。确定了DBA/2小鼠和KM小鼠在炭疽杆菌弱毒株芽胞研究中的适用性。使用KM小鼠评价了不同canSNP基因型炭疽杆菌芽胞的毒力差异，结果表明，不同canSNP基因型炭疽杆菌由于所含pXO2质粒拷贝数的差异导致芽胞的毒力不同。使用DBA/2小鼠评价了S-层蛋白BA3338缺失对炭疽杆菌芽胞毒力的影响，表明BA3338基因的缺失导致炭疽杆菌芽胞毒力降低。     

我国内蒙古褐斑鼠兔一新亚种

在我国,褐斑鼠兔(帕氏鼠兔或蒙古鼠兔)Ochotona pallasi的记录,过去只有Thoma(1912)根据新疆哈密县天山的6标本所发表的哈密亚种O.p.hamica。我们于1972—1973及1975—1976年间在内蒙古和新疆采到一些褐斑鼠兔标本。经研究,采自新疆北塔山的13个标本属蒙古亚种O.p.pricei,为我国亚种的新纪录;采自内蒙古的11个标本则为新亚种,描记于下。     

急性高原性低氧对三种小哺乳动物肝脏作用的比较

人工低气压舱模拟高原低氧,观察实验动物小白鼠、豚鼠及野生动物达乌尔鼠兔,在海拔5000米及8000米24小时内的几种生理效应,并与2300米海拔对照组进行了比较。发现随着海拔高度的升高:1.3种动物体重明显下降;2.肝糖原含量明显降低:小鼠、达乌尔鼠兔与豚鼠肝糖原在8000米时分别为2300米含量的62%,35%及 9%:3.小鼠、达乌尔鼠兔及豚鼠的肝脂肪累积量依次增大;4.肝蛋白质含量减少;5.SGPT与SGOT活力升高;6.肝细胞溶酶体的酸性磷酸酶与芳基硫酸脂酶活力升高。肝组织形态学观察结果与生化检测结果一致,豚鼠在8000米海拔时,肝细胞出现气球样变,脂肪变性及灶性液化性坏死等变化。综合分析,这3种动物对极度低氧的耐受性依顺序为小鼠、达乌尔鼠兔、豚鼠。     

Maximum shields: the assembly and function of the bacterial spore coat

Spores produced by bacilli and clostridia are surrounded by a multilayered protein shell called the coat. As the armor-like appearance of the coat suggests, this structure, along with others within the spore, confers the remarkable resistance properties that make Bacillus anthracis spores such potent biological weapons. Here, I review recent studies of coat assembly in the model organism Bacillus subtilis, and explore the implications of these findings for coat assembly in B. anthracis and for defense against biological weapons.     

Survival of bacillus licheniformis on human skin.

The colonization and survival of Bacillus species, members of the cutaneous microbial community of humans, were investigated by applying spores of Bacillus licheniformis to the forearms of volunteers. Four strains were tested, including the bacitracin producer ATCC 10716 and its bacitracin-negative mutant. Germination occurred within 24 h. Significant differences in survival population and duration were found among the test strains; however, ATCC 10716 and its mutant produced statistically similar survival curves. In general, an inoculum density of 10(4) colony-forming units per cm2 allowed survival for at least 2 weeks. Individual variation was extreme, for one subject harbored bacilli for over 2 months and another eliminated the microorganism within 3 days. Individuals could be differentiated into long-term (greater than 21 days) and short-term (less than 14 days) carriers. Eight of the 11 volunteers (73%) inoculated with ATCC 10716 carried it for 2 weeks, and 5 subjects (45%) continued to support the bacilli for 3 weeks. Spreading of the organism to other regions of the body occurred, but bacilli were not detected in these areas beyond 6 days.     

Targeting proteins to the cell wall of sporulating Bacillus anthracis

Dormant spores of Bacillus anthracis germinate during host infection and their vegetative growth and dissemination precipitate anthrax disease. Upon host death, bacilli engage a developmental programme to generate infectious spores within carcasses. Hallmark of sporulation in Bacillus spp. is the formation of an asymmetric division septum between mother cell and forespore compartments. We show here that sortase C (SrtC) cleaves the LPNTA sorting signal of BasH and BasI, thereby targeting both polypeptides to the cell wall of sporulating bacilli. Sortase substrates are initially produced in different cell compartments and at different developmental stages but penultimately decorate the envelope of the maturing spore. srtC mutants appear to display no defect during the initial stages of infection and precipitate lethal anthrax disease in guinea pigs at a similar rate as wild-type B. anthracis strain Ames. Unlike wild-type bacilli, srtC mutants do not readily form spores in guinea pig tissue or sheep blood unless their vegetative forms are exposed to air.     

Pulmonary Tuberculosis Apparently Caused by the Avian Tubercle Bacillus

Avian tubercle bacilli were repeatedly isolated from the sputum of a 65-year-old man who had cavitary disease in the upper lobe of the right lung. The clinical picture resembled that of pulmonary tuberculosis caused by the human type of tubercle bacilli, but the response to antituberculosis chemotherapy was unsatisfactory and the patient''s sputum remained positive. The bacilli were markedly pathogenic to chickens and rabbits but failed to produce progressive disease in guinea pigs. This is in accord with the properties of tubercle bacilli of the avian type.     

Anthrax vaccine design: strategies to achieve comprehensive protection against spore,bacillus, and toxin

The successful use of Bacillus anthracis as a lethal biological weapon has prompted renewed research interest in the development of more effective vaccines against anthrax. The disease consists of three critical components: spore, bacillus, and toxin, elimination of any of which confers at least partial protection against anthrax. Current remedies rely on postexposure antibiotics to eliminate bacilli and pre- and postexposure vaccination to target primarily toxins. Vaccines effective against toxin have been licensed for human use, but need improvement. Vaccines against bacilli have recently been developed by us and others. Whether effective vaccines will be developed against spores is still an open question. An ideal vaccine would confer simultaneous protection against spores, bacilli, and toxins. One step towards this goal is our dually active vaccine, designed to destroy both bacilli and toxin. Existing and potential strategies towards potent and effective anthrax vaccines are discussed in this review.     

Protein Translation Inhibition by Stachybotrys chartarum Conidia with and without the Mycotoxin Containing Polysaccharide Matrix

Recent studies have correlated the presence of Stachybotrys chartarum in structures with SBS. S. chartarum produces mycotoxins that are thought to produce some of the symptoms reported in sick-building syndrome (SBS). The conidia (spores) produced by Stachybotrys species are not commonly found in the air of buildings that have been found to contain significant interior growth of this organism. This could be due in part to the large size of the Stachybotrys spores, or the organism growing in hidden areas such as wall cavities. However, individuals in buildings with significant Stachybotrys growth frequently display symptoms that may be attributed to exposure to the organism's mycotoxins. In addition, Stachybotrys colonies produce a "slime" or polysaccharide (carbohydrate) matrix that coats the hyphae and the spores. The intent of this project was to determine whether the carbohydrate matrix and the mycotoxins embedded in it could be removed from the spores by repeated washings with either aqueous or organic solvents. The results demonstrated that the process of spore washing removed compounds that were toxic in a protein translation assay as compared to spores that were washed with an organic solution, however a correlation between carbohydrate removal during the washing process and the removal of mycotoxins from the spore surface was not observed. These data demonstrated that mycotoxins are not likely to be found exclusively in the carbohydrate matrix of the spores. Therefore, mycotoxin removal from the spore surface can occur without significant loss of polysaccharide. We also showed that toxic substances may be removed from the spore surface with an aqueous solution. These results suggest that satratoxins are soluble in aqueous solutions without being bound to water-soluble moieties, such as the carbohydrate slime matrix.     

Distinctness of spore and vegetative cellular fatty acid profiles of some aerobic endospore-forming bacilli

A gas chromatographic analysis method was employed to determine the cellular fatty acid (CFA) profiles of spores and vegetative cells of some aerobic endospore-forming bacilli. The harvests of experimental strains were processed to obtain pure spores and acquire whole cell fatty acid methyl esters for the subsequent gas chromatographic analysis, and the corresponding vegetative cells were set as control. Evaluation of reproducibility of spore CFA components revealed that, provided under standardized experimental procedure, spore CFA composition was stable enough for research purposes. Fatty acids recovered in spores in greater quantities were saturated branched-chain acids containing 15 and 17 carbon atoms, similar to the vegetative cells. Commonly, the proportions of saturated branched-chain acids in spores were greater than in vegetative cells. The dendrograms obtained by cluster analysis provided some meaningful taxonomic information of the experimental strains. The fatty acids analysis of spores seems to be a promising supplementary tool for the chemotaxonomic research of aerobic endospore-forming bacilli.