检查细菌呼吸方式和云霞生的一管多用鉴定培养基

自行研制一种细菌呼吸方式和运动性的一管多用鉴定细菌用培养基,可通过穿刺接种,３７℃,２４－４８ｈ培养后在同一支高层培养基判定好氧性,厌氧性及运动性,经过接种临床常上菌属１２０个菌株的试验结果表明,该培养基有很好的实用性,其本方组合合理,材料易得,成本不高,质量稳定,使用简单,判定容易,可以省去厌氧菌２检查器材的试剂,有助于提高细菌鉴定工作效率 质量。     

细菌产纤维素酶和脂肪酶固体培养基及接种和培养时间的研究

为准确鉴定和筛选产纤维素和脂肪酶细菌，通过平板扩散法测定不同氮源培养基对细菌产纤维素酶和不同碳源培养基对细菌产脂肪酶活性的影响，确定细菌产纤维素酶和脂肪酶的最佳培养基，利用最佳培养基研究不同琼脂含量、海水和淡水溶剂、菌种的培养时间及接种后的培养时间对细菌纤维素酶和脂肪酶活性的影响。结果表明，以蛋白胨为氮源的A培养基为细菌产纤维素酶最佳培养基，以Tween-20为碳源的培养基为细菌产脂肪酶最佳培养基；培养基中琼脂的最佳用量均为13‰；所有菌株在海水培养基上产生的纤维素酶活性比淡水培养基上高，但脂肪酶活性并非如此；鉴定和筛选产纤维素酶和脂肪酶细菌接种菌种的最佳培养时间分别为18 h和24~32 h，测定细菌产纤维素酶和脂肪酶的最佳培养时间分别为48~72 h和120 h。     

明胶碳粒的研制及其在明胶液化试验中的应用

自行研制明胶碳粒用于细菌鉴定中的明胶液化试验。将明胶碳粒加入基质中,经３７℃１６～２０ｈ培养后,如细菌具有明胶酶,基质即变黑色,反之明胶碳粒在基质中沉淀,基质不变色。经接种标准菌株和临床常见菌２０３株,试验结果表明,该明胶碳粒使用简便,容易判定,特异性强,灵敏度高,质量稳定,可以代替国外同类产品。有助于提高细菌鉴定工作效率和质量,降低检测成本,具有很好的应用价值。     

明胶碳料的研制及其在明胶液化试验中的应用

自行研制明胶碳粒用于细菌鉴定中的明胶液化试验。将明胶碳粒加入基质中经３７℃ １６￣２０ｈ培养后,如细菌具有明胶酶,其质即变黑色,反之明胶碳粒在基质中沉淀,基质不变色,经接种标准菌株和临床常见菌２０３株,试验结果表明,该明胶碳粒使用简便,容易判定,特异性强,灵敏度高,质量稳定,可以代替国外同类产品。有助于提高细菌鉴定工作效率和质量,降低检测成本,具有很好的应用价值。     

细菌素发酵条件的研究进展

自从乳酸乳球菌产生的细菌素--Nisin批准作为食品防腐剂以来,细菌素的研究已成为微生物学研究中的一个活跃领域,研究内容主要涉及产细菌素菌株的筛选和鉴定,细菌素的分离纯化、理化性质、作用机制、发酵条件和应用以及工程菌株的构建等。人们已从不同生态环境中筛选到产细菌素的菌株,如新鲜牛奶、发酵奶制品、豆芽、泡菜、香肠和动物肠道等.细菌素的产量除了与菌株自身性质有关外,发酵条件对细菌素的产量有很大影响,如培养基成分、有机溶剂、培养温度、培养时间、培养方式、起始pH、接种量和接种种龄等,其中以培养基成分、有机溶剂的添加和培养温度影响较大。     

哺乳类基因工程的一些实验操作 实验10X噬菌体DNA 体外包装

一、需用的菌株及其特性鉴定 1.菌株及其基因型 (1）大肠杆菌E. coli BHB2688，基因型为：N205 rec＾一〔rimm"`9 clts, b2, red-, Earn, Sam/r.lo (2）大肠杆菌E. coli BHB 2690，基因型为： N205 recA- [rimm"9`. cIts, b2, red-. Dam, Sam/r]. (3）大肠杆菌E. coli K802，基因型为：hsdR+, hsdM+.} gal-, met-, SUPHO 2.鉴定clrs基因 (1) BHB 2688和BHB 2690各自接种在2只LB 培养基上。一只置32℃下培养，另一只置42℃下培 养。在32℃培养的平板上挑取单菌落，接种在LB培 养液中，32℃培养过夜。 (2）再将培养液中生长的细菌划线接种在2只 LB培养基上，分别置32℃和42℃下培养。如果细菌 只在32℃ 下生长，则可用于制备包装用的抽提物。 3.鉴定，cA基因 (1)在LB平板上，平行划线接种BHB 2688, BHB 2690和K802o (2）用厚纸遮住培养皿的一半，打开培养皿盖置 紫外线下照射。然后在犯℃下培养过夜。 (3）厚纸遮挡部分的培养基上，BHB2688和BHB 269。生长，紫外线照射的培养基上则不生长。K802 不受紫外线照射的影响都能够生长。     

土地类芽胞杆菌(Paenibacillus terrae)新菌株NK3-4及其功能

【目的】分离筛选出一株能溶解矿物磷、钾、硅,防治作物病害,具有固氮活性的细菌。【方法】从大豆(Glycine max)田中采集大豆根周土壤,用钾长石选择性培养基进行加富培养,从加富培养物中分离具有溶解硅酸盐矿物能力的细菌。采用平板对峙法,从分离到的菌株中筛选出一株对大豆根腐病菌尖孢镰刀霉(Fusarium oxysporum)抑制作用强的菌株,再通过摇瓶培养法测定该菌株溶解矿物钾、硅、磷的能力,用改良阿须贝(Ashby)无氮液体培养基培养待测菌株,测定菌株的固氮功能。依据形态观察、生理生化反应及16S rRNA基因序列分析结果鉴定菌株。【结果】从健康大豆根周分离筛选出一株编号为NK3-4的细菌,该细菌在平皿上对尖孢镰刀霉的抑菌带宽度达到8.0 mm;培养24 h后,含有钾长石的液体培养基中速效钾浓度比培养基中不含钾长石的处理浓度高15.0 mg/L,可溶性硅浓度比不接种对照高51.3 mg/L;在磷酸三钙为唯一磷源的液体培养基中培养8 d后,培养基中可溶性磷浓度是不接种对照的4.8倍;在改良阿须贝液体培养基中培养15 d后,培养基中可溶性氮浓度是不接种对照的4.6倍,每升培养基中菌体氮含量达到12.7 mg。经鉴定,该菌株为土地类芽胞杆菌(Paenibacillus terrae)的新菌株。【结论】NK3-4是一株具有多种生物活性的土地类芽胞杆菌新菌株,可应用于生物农药及生物肥料的研制与开发。     

细菌性抗原的快速检测方法

<正> 传统上,病原性微生物引起的感染,系将病原性材料接种于适宜的培养基上进行培养,当生长后再作进一步的试验进行鉴定。这些方法检测速度慢,取决于细菌的生长速度。最近以来,转向于直接由病理材料中检测细菌性抗原及其他产物的方法上来。如果使用的方法敏感性和特异性高,则可能不需要等待被检菌在人工培养基上生长即可作出鉴别。除了对敏感性试验方法和有关被检菌其他资料的需要外,这些方法一般不能代替培养法,而只能作为一种辅助性的方法使用。本文仅就由体液中检测细菌性抗原的一些免疫学方法和检测细菌成份及其代谢产物的一些非免疫学方法进行综述。     

革兰氏阴性杆菌、弧菌新编码鉴定法的建立和应用研究

细菌种类不同,其生化特征不一。本文对革兰氏阴性杆菌、弧菌等4个科、36个菌属、103个种及4个生物群的细菌进行7位数编码,建立了新革兰氏阴性杆菌、弧菌编码鉴定法。为此,编著《革兰氏阴性杆菌、弧菌新编码鉴定手册》,介绍此法的理论、有关技术及编码检索表。制备出发酵型与氧化型共用的一套鉴定系列培养基,并对部分培养基作了改良。使用新编鉴定法鉴定23个菌属709株标准菌株及临床参考菌株,与常规法鉴定结果的鉴定符合率为97.74%。本法的操作简单。判定容易,应用面广,是目前我国的最佳方法,适合基层实验室使用。与法国的     

基于培养组学的健康人口腔细菌分离鉴定初探CSCD

目的 通过对口腔的不同部位进行细菌分离,扩展对口腔微生物多样性的认识,以期为后续的口腔菌群研究提供参考。方法 通过培养组学方法分离口腔不同部位的细菌,采集2个健康人扁桃体、唾液、牙菌斑3个部位的样本,使用13种培养基并于需氧和厌氧条件下进行培养,采用16S rRNA基因全长测序分析。结果 总计获得144株菌,分属36个种,10个科,3个门。其中,链球菌属细菌种类最多。基于16S rRNA基因全长相似度98.65%的阈值判定,获得5种潜在全新细菌。3个部位中,扁桃体分离的细菌种类多样性最丰富。结论 13种培养基中,BHI培养基获得的口腔细菌多样性最好;BAB培养基与TSA培养基更适合口腔链球菌生长,链球菌的比例更高;LBB培养基上只有较单一的口腔细菌生长,不适于广谱分离口腔细菌。     

Effect of bacterial heterogeneity on adhesion to uniform collectors by monoclonal populations

Abstract Transport of bacteria over significant distances through aquifer sediments occurs primarily among bacteria with low affinity for sediment materials. Bacterial affinity for a uniform collector surface has been represented quantitatively by a collision efficiency (α), defined as the fraction of colliding cells that adhere to the collector surface. Using a new method for estimating α during advective transport of monoclonal bacterial populations through a uniform bed of 40-μm borosilicate glass spheres, we found that α decreased 10-fold over a bed depth of only 1 cm. Depth-dependent differences in α were not related to variation in bacterial size or intra-strain genetic variation. Intra-population heterogeneity in biocolloid-collector affinity may be important determinant of subsurface bacterial transport characteristics, with critical implications for pathogen transport and dispersal of bacteria for the remediation of hazardous waste.     

3种革兰氏阴性细菌及其L型内毒素含量的测定

本文采用鲎试剂对大肠杆菌（ＡＴＣＣ２５９２２）、伤寒杆菌、绿脓杆菌（ＡＴＣＣ７８５３）及它们的Ｌ型内毒素的含量进行测定。结果显示细菌型与细菌Ｌ型均具有内毒素,但细菌Ｌ型内毒素含量较细菌型低（约为１／３￣１／２）。因此,认为细菌Ｌ型仍有一定的致病性。     

Respiratory viral infection predisposing for bacterial disease: a concise review

Although bacterial superinfection in viral respiratory disease is a clinically well documented phenomenon, the pathogenic mechanisms are still poorly understood. Recent studies have revealed some of the mechanisms involved. Physical damage to respiratory cells as a result of viral infection may lead to opportunistic adherence of bacteria. Enhanced bacterial adherence by specific mechanisms has been documented for respiratory cells infected with influenza A virus, respiratory syncytial virus and adenovirus in both in vitro and in vivo models. To date, results of various experimental studies indicate that different mechanisms for increased bacterial adherence induced by viruses are operating for specific viral-bacterial combinations. In the present review, a number of key findings obtained during the past two decades is presented and discussed.     

Sequencing, cloning and expression of a β-1,4-mannanase gene, manA, from the extremely thermophilic anaerobic bacterium, Caldicellulosiruptor Rt8B.4

Abstract We report here the isolation of a Renibacterium salmoninarum DNA sequence capable of transforming a non-invasive Escherichia coli strain into a microorganism able to enter the fish cell line, CHSE-214. Immunofluorescence and electron microscopy techniques were used to assess the acquired invasive phenotype by HB101 E. coli cells, upon transformation with pPMV-189. This plasmid carries a 2282-bp R. salmoninarum DNA segment. The invasive phenotype is qonserved upon deletion of approximately 1000 bp at the 3' end of the insert. The remaining segment contains an ORF region encoding a putative protein of about 30 kDa.     

丛枝菌根真菌和根瘤菌互作对苜蓿根际土壤细菌群落结构的影响及PICRUSt功能预测分析

【背景】紫花苜蓿是优良的豆科牧草,可以与丛枝菌根(Arbuscular mycorrhizae,AM)真菌和根瘤菌形成共生关系,接种AM真菌和根瘤菌可以促进土壤氮、磷循环以及提高苜蓿产量。【目的】探究接种AM真菌和根瘤菌对苜蓿根际细菌群落结构和功能的影响。【方法】采集6个不同处理组苜蓿根际、非根际土壤样品,基于细菌16S rRNA基因V3?V4区进行高通量测序,分析比较不同处理组苜蓿根际、非根际土壤中细菌群落分布的规律,并采用PICRUSt软件对不同处理组间菌群功能进行预测。【结果】36个土壤样品中共检测到3 849个OTU,分属于50门59纲132目249科595属398种。其中主要的优势菌门为Proteobacteria (52.81%?81.46%)、Bacteroidetes (7.83%?19.68%)及Actinobacteria (2.21%?16.4%)。与不接种相比,接种根内球囊霉和摩西球囊霉分别提高了Gammaproteobacteria和Bacteroidia有益菌的丰度,接种根瘤菌提高了固氮菌(Alphaproteobacteria)的丰度。PICRUSt功能预测表明,细菌菌群共有35个子功能,菌群功能丰富,代谢为最主要的功能,并且接种根瘤菌可增加氨基酸代谢,从而有利于植株N素循环,而接种AM真菌可能对于N循环有一定的抑制作用,相比于单接种AM真菌,双接种AM真菌和根瘤菌处理组碳水化合物代谢更强,从而更有益于植株的氮、磷循环。【结论】接种AM真菌和根瘤菌可分别提高苜蓿根系与氮、磷循环有关的不同有益菌的丰度,从而更有益于植株的氮、磷循环,该结果为提高植株养分吸收、提高苜蓿产量以及菌肥开发利用提供了科学依据。     

Characterization of the plant growth promoting bacterium,Enterobacter cloacae MSR1, isolated from roots of non-nodulating Medicago sativa

The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future.     

Bacterial foraging algorithm with varying population

Most of evolutionary algorithms (EAs) are based on a fixed population. However, due to this feature, such algorithms do not fully explore the potential of searching ability and are time consuming. This paper presents a novel nature-inspired heuristic optimization algorithm: bacterial foraging algorithm with varying population (BFAVP), based on a more bacterially-realistic model of bacterial foraging patterns, which incorporates a varying population framework and the underlying mechanisms of bacterial chemotaxis, metabolism, proliferation, elimination and quorum sensing. In order to evaluate its merits, BFAVP has been tested on several benchmark functions and the results show that it performs better than other popularly used EAs, in terms of both accuracy and convergency.     

Listeria monocytogenes Triggers the Cell Surface Expression of Gp96 Protein and Interacts with Its N Terminus to Support Cellular Infection

Listeria monocytogenes is an intracellular food-borne pathogen causing listeriosis in humans. This bacterium deploys an arsenal of virulence factors that act in concert to promote cellular infection. Bacterial surface proteins are of primary importance in the process of host cell invasion. They interact with host cellular receptors, inducing/modulating specific cellular responses. We previously identified Vip, a Listeria surface protein covalently attached to the bacterial cell wall acting as a key virulence factor. We have shown that Vip interacts with Gp96 localized at the surface of host cells during invasion and that this interaction is critical for a successful infection in vivo. To better understand the importance of Vip-Gp96 interaction during infection, we aimed to characterize this interaction at the molecular level. Here we demonstrate that, during infection, L. monocytogenes triggers the cellular redistribution of Gp96, inducing its exposure at the cell surface. Upon infection, Gp96 N-terminal domain is exposed to the extracellular milieu in L2071 fibroblasts and interacts with Vip expressed by Listeria. We identified Gp96 (Asp¹–Leu¹⁷⁰) as sufficient to interact with Vip; however, we also showed that the region Tyr¹⁷⁹–Leu³⁹⁰ of Gp96 is important for the interaction. Our findings unravel the Listeria-induced surface expression of Gp96 and the topology of its insertion on the plasma membrane and improve our knowledge on the Vip-Gp96 interaction during Listeria infection.