蜡样芽孢杆菌检测方法研究进展

蜡样芽孢杆菌是一种可引起食物中毒的常见食源性细菌,属于革兰氏阳性的条件致病菌,广泛存在于土壤、空气、水及植物源、动物源加工的食品中。近年发现也能感染包括人在内的多种动物,是一种人兽共患性细菌,特别是能够引起人畜肠道疾病,导致腹泻型或呕吐型食物中毒。快速准确检测蜡样芽孢杆菌是控制其污染和感染后治疗的关键环节。作者对蜡样芽孢杆菌的检测方法进行了全面详细的总结,主要包括传统检测方法、普通PCR、多重PCR（mPCR）、实时荧光定量PCR（Real-time PCR）、叠氮溴化丙锭-定量PCR（PMA-qPCR）、微滴数字PCR技术（ddPCR）、环介导等温扩增（LAMP）及酶联免疫吸附测定（ELISA）。从传统方法到新兴技术,涉及传统检测技术、分子生物学检测和免疫学检测技术,作者主要总结了各方法的原理、检测范围,并对各方法的优缺点进行了比较。这些检测方法的灵敏度、精确度、样本要求等有所不同,可根据检测需要和条件限制进行选择。将分子生物学方法和免疫学等方法有效地结合起来,多角度多层次地对样品进行检测,可全面而准确地呈现检测结果。蜡样芽孢杆菌能产生多种毒素,这些毒素决定了其致病性,所以除了检测菌体外,还可以对毒素进行检测,有助于确定病原及其致病力。总的来说,蜡样芽孢杆菌对人畜的健康安全均构成了威胁,快速准确地检测能有效辅助治疗和提前预防,作者将主要检测方法进行了总结,希望能有助于全面准确地评估蜡样芽孢杆菌的风险,为主动监测和预警提供科学依据。     

3株蜡样芽孢杆菌产酶特性的检测

为了检测3株蜡样芽孢杆菌的产酶特性,分别对其进行淀粉水解试验、明胶水解试验、石蕊牛奶试验、卵磷脂酶产生试验、酪氨酸水解试验、酪素水解试验、过氧化氢酶试验和吲哚试验。结果显示,3株菌均能产生淀粉水解酶、蛋白酶、卵磷脂酶和过氧化氢酶,水解石蕊牛奶和酪素,不能产生吲哚和酪氨酸酶。说明3株蜡样芽孢杆菌均有望成为制备微生态制剂的候选菌株。     

蜡样芽孢杆菌对鸡下痢的治疗效果

一、蜡样芽孢杆菌的生物学特性菌群失调如不能及时进行适当的调整,将会引起严重的后果.兽医临床上常用的调整菌群的方法有三种:1、抗菌素法这是临床兽医最常采用的方法,有时收效甚好。但如从消化道给药,抗菌素法本身就有十分严重的潜在危险,长期使用常常引起耐药性的产生、     

理化因素对蜡样芽孢杆菌生长的影响

本文研究温度、pH值、紫外线、固态介质对来自牛乳中的一株蜡样芽孢杆菌生长的影响。结果表明该菌的适应能力强，因此，在乳品生产过程中要严格控制芽孢杆菌的污染。     

蜡样芽孢杆菌对大肠杆菌的体外抑制研究

该试验通过蜡样芽孢杆菌和大肠杆菌同时接种及分别先后接种等3种不同的接种方式分别于4h、8h、12h、24h、36h、48h6个时间点观察抑制效果,以确定最佳接种方式。研究表明,先接种蜡样芽孢杆菌后接种大肠杆菌,抑制作用最强;蜡样芽孢杆菌和大肠杆菌同时接种次之;先接种大肠杆菌后接种蜡样芽孢杆菌,抑制作用最弱。并且每种接种方式都在12h左右出现抑制高峰。     

侧孢芽孢杆菌分泌溶菌酶的变化规律及酶学特性分析

试验测定了侧孢芽孢杆菌在不同时间分泌溶菌酶的变化规律,以及不同温度和pH预处理对溶菌酶活性的影响。结果表明,侧孢芽孢杆菌在培养12h时产溶菌酶量最大,溶菌酶活力最高时的温度为33℃,最适pH为5.0。     

蜡样芽孢杆菌毒力因子及防治措施

蜡样芽孢杆菌是一种重要的食源性条件致病菌,可引起肠道感染,亦可造成局部组织和全身性感染。近年来,国内外出现多例临床报道由蜡样芽孢杆菌引起的类似炭疽样感染,值得引起养殖业的研究重视。总结了蜡样芽孢杆菌主要的毒力因子,为科研人员的研究提供一定理论基础,同时对蜡样芽孢杆菌的防治提出了建议,以期为广大畜牧从业者提供参考。     

益生菌发酵工艺中蜡样芽孢杆菌的分离鉴定

在益生菌生产发酵工艺中常出现耐热杂菌污染的现象,导致产品质量下降,甚至生产失败,从而造成经济损失。本试验为确定发酵工艺中被污染的耐热性杂菌,采集污染发酵液为检样,分离及纯化一株菌株(命名为YBNR),通过形态学、生化试验及16sRNA测序等方法进行菌株鉴定。结果显示:污染发酵工艺的耐热菌为蜡样芽孢杆菌。     

马蜡样芽孢杆菌感染病例的诊断

2021年11月,山东某马场出现马匹轻微腹泻后急性死亡病例。通过了解该马场饲养管理、饲料组成,剖检病死马匹,实验室检测饲料滤过液、饮水、肠内容物滤过液pH,进行肠内容物中病原菌分离鉴定及小鼠攻毒试验,确定该病例发病原因为由气温骤降和饲料配制不当诱发的肠道蜡样芽孢杆菌感染。遂采取减少青贮饲料的添加量、增加干草的添加比例、增设饮水加热装置及饲料中添加抗生素等措施,该马场未见新增死亡病例。     

饲用芽孢乳酸菌的生物学特性研究

试验研究了芽孢乳酸菌的生长特性、泌酸能力、高温耐受性、耐酸性、胆盐耐受性和抑菌能力,旨在为微生态饲料添加剂的研发提供试验依据。结果表明,芽孢乳酸菌在30 h时菌体质量浓度达到最高值,在32 h时产酸量最高,最后在pH 3.80左右趋于稳定;芽孢乳酸菌经90℃处理10 min后存活率达到73.47%,pH 2.0及1.0%胆盐处理3 h后存活率分别为54.69%、24.36%;芽孢乳酸菌对大肠杆菌、沙门氏菌、金黄色葡萄球菌均具有较好的抑菌性能,抑菌圈直径分别为18.38、19.76、17.42 mm。结果说明,芽孢乳酸菌具备良好的生物学特性,是一株优异的益生菌株。     

蜡样芽孢杆菌发酵条件的优化

<正>蜡样芽孢杆菌是一种常用的益生菌。蜡样芽孢杆菌进入肠道后,消耗肠道内过多氧气,创造厌氧环境,促进厌氧菌生长,能够调整肠道菌群失调,改善微生态环境,达到抑制有害好氧菌生长,有利于有益厌氧菌生存,提高动物的饲料利用率并促进动物生长。     

Superoxide, superoxide dismutase and the respiratory burst

Phagocytes undergo a sharp burst of oxygen consumption when engulfing bacteria. This oxygen is enzymatically reduced to toxic metabolites which are essential to the bactericidal action of the cell. Oxygen metabolites formed in this burst as well as other intermediates formed in biological reduction reactions do not selectively reserve their toxicity for microorganisms. Cells help to guard their organelles against the toxic effects of oxygen by producing intracellular enzymes such as superoxide dismutase. Though superoxide dismutase is found in relatively high concentrations inside cells, there are only small amounts in extracellular fluids. This may account for some of the local tissue damage surrounding aggregates of neutrophils in inflammatory reactions. A pharmacological preparation of superoxide dismutase has shown efficacy in preventing some of the pathological changes seen in degenerative arthritis.     

Identification of the copper-zinc superoxide dismutase activity in Mycoplasma hyopneumoniae

Copper-zinc superoxide dismutase (Cu/ZnSOD), a key enzyme in defense against toxic oxygen-free radicals, is widespread in eukaryotes and several species of gram-negative bacteria. The presence of this enzyme in Mycoplasma hyopneumoniae (M. hyopneumoniae), the primary pathogen of mycoplasmal pneumonia in pigs, was examined since the polyclonal antibody against bovine Cu/ZnSOD was dominantly cross-reactive with the M. hyopneumoniae Cu/ZnSOD from whole cellular proteins. In situ activity staining on SDS-PAGE showed that the molecular mass of M. hyopneumoniae Cu/ZnSOD in reducing form was approximately 17kDa. The presence of Cu and Zn ions at the active site of the enzyme was confirmed on the basis of inhibition by KCN and by H(2)O(2). The activity of M. hyopneumoniae Cu/ZnSOD on both SDS- and native-polyacrylamide gels was completely inhibited by 2mM KCN and the gels showed no iron-containing SOD (FeSOD) or manganese-containing SOD (MnSOD) in the crude extracts. The activity of M. hyopneumoniae Cu/ZnSOD in crude extract was 70units/mg protein and was 55% inhibited by 5mM KCN and 56% inactivated by 40mM H(2)O(2). This enzyme was growth-stage dependent and evidenced markedly higher production during the early log phase. Different expression levels of Cu/ZnSOD activity in field isolates were also detected. Taken together, the presence of Cu/ZnSOD in M. hyopneumoniae was identified for the first time.     

超氧化物歧化酶在苜蓿抗寒锻炼过程中的作用

对苜蓿Medicago sativa抗寒锻炼过程中膜透性和超氧化物歧化酶(SOD)活性进行测定,通过苜蓿组织冰冻半致死温度(LT50)说明在抗寒锻炼过程中苜蓿抗寒性的变化。结果表明,在不同低温处理下,苜蓿叶片和根茎组织电解质透出率呈现出S型曲线变化。抗寒锻炼过程中,苜蓿组织LT50从9月初的-6.9℃下降到11月初的-15.6℃,下降了8.7℃。随着秋季气温的下降,苜蓿叶片SOD活性显著增加,11月上旬达到最高峰,此后显著下降。这说明SOD在抗寒锻炼过程中起着重要的保护作用,当苜蓿获得抗寒能力后,SOD活性逐渐下降。在抗寒锻炼过程中,苜蓿根茎SOD活性的变化与叶片中SOD活性的变化规律不一致,苜蓿根茎中SOD活性水平显著高于叶片中的SOD活性水平。聚丙烯酰胺凝胶电泳分析结果显示,不同苜蓿品种具有6条共同的SOD同工酶酶带。适应高寒地区气候条件的当地材料同德杂种苜蓿表现出与其他苜蓿品种较大的特异性。抑制试验表明苜蓿SOD为CuZn-SOD。     

构建铜锌超氧化物歧化酶毕赤酵母转化子及其高表达分析

设计铜锌超氧化物歧化酶酵母偏爱密码子并化学合成,与pPIC9K连接,构建酵母偏爱密码子的铜锌超氧化物歧化酶基因真核表达载体;通过电转化和持续加压筛选毕赤酵母GS115高拷贝转化子,获得重组高表达酵母菌株建立主种子批。经Southern blot鉴定,高拷贝基因比低拷贝高2～8倍,表达活性高2～4倍。重组菌的目的基因拷贝数与表达产物呈正相关;表达产物为二聚体,相对分子质量为40 000左右,低糖基化,均为分泌表达。West-ern blot法分析,对Cu,Zn-SOD抗体具有特异性反应。转化子在培养16h后进入对数生长期,24h后进入生长稳定期;转化子培养20h左右进行诱导表达最为合适。Cu,Zn-SOD转化子用正交试验筛选摇瓶的诱导表达条件,经诱导表达,Cu,Zn-SOD表达上清最高活性大于600U/mL。确立最适摇瓶培养条件为pH6.0,30℃,1.5%甲醇诱导浓度诱导72h上清的目的蛋白表达最好。高拷贝的3株重组菌经50次传代后插入的目的基因保持稳定。本研究为中试工艺研究奠定了基础。     

镉诱导小鼠卵巢颗粒细胞凋亡时MDA含量及SOD活性变化

镉（Cadium，Cd）是一种有色重金属元素，是一种半衰期很长（20年以上）的多器官、多系统毒物，于1817年被Stromeyer发现。镉对雌性生殖系统也具有明显的毒性作用，镉可直接作用于卵巢，引起卵巢积液、出血、萎缩等病理改变，使卵母细胞损害，成熟卵泡减少或空泡变、闭锁卵泡增多，干扰排卵和受精过程，引起暂时性不育；还可以抑制卵巢颗粒和／或黄体细胞类固醇生物合成，还可能对雌激素受体、孕酮受体及基因表达产生影响。镉还可以激活应激蛋白酶，使细胞内Ca^2＋增加，原癌基因c-myc、c—fos、C—jun表达增强；镉还可以引起DNA单链断裂，并损害DNA修复酶系统，诱导多种细胞凋亡。因此，WHO确定镉为优先研究的食品污染物，联合国环境规划署提出12种具有全球性意义的危险化学物质，镉被列为首位。但镉对卵巢颗粒细胞（GC）的体内毒性研究国内外罕见报道，本研究探讨了氧自由基在镉诱导卵巢颗粒细胞凋亡过程中所起到的作用。     

Evaluation of intestinal villus height in rats after ischemia and reperfusion by administration of superoxide dismutase, polyethylene glycol-conjugated superoxide dismutase, and two 21-aminosteroids.

Intestinal ischemia was induced and maintained for 60 minutes in male Sprague-Dawley rats weighing 175 to 225 g. Prior to reperfusion, the following drugs were administered via the caudal vena cava: 0.9% NaCl (0.5 ml), superoxide dismutase (SOD; 1,000 IU/kg of body weight), polyethylene glycol-conjugated SOD (PEG-SOD; 1,000 IU/kg), or the 21-aminosteroids, U74006F (3 mg/kg) or U78715G (3 mg/kg). A sham-operated control group was included. Animals from each group were euthanatized at 5 periods of reperfusion: 5 minutes, 30 minutes, 18 hours, 3 days, and 7 days after reperfusion. Fixed tissues were embedded in paraffin, sectioned at 5 microns, and stained with H&E. Villi profiled in cross section were measured from the crypt villus junction to the tip of the villus. The mean villus height for each rat was calculated and compared by two-way ANOVA to determine the effects of time and treatment. Villus height was maintained after 30 minutes of reperfusion in rats of the sham- and U74006F-treated groups; U78715G and SOD treatment attenuated the loss in villus height, and villus height was not maintained in the PEG-SOD- and 0.9% NaCl-treated rats. In all rats, villus height was comparable to, or was greater than villus height in sham-operated controls by 18 hours after reperfusion in all animals and remained constant through 7 days. Administration of the 21-aminosteroids maintained villus height after ischemia and reperfusion. Treatment with PEG-SOD did not maintain villus height to the degree observed in rats treated with SOD.