泸型酒酒醅与窖泥中乳酸菌群落结构差异

乳酸菌对泸型酒风味品质的发酵形成具有重要作用.为促进对酒醅和窖泥中乳酸菌群落物种组成、发酵演替规律以及表型差异的深入认识,采用分子生态学技术,在种水平上对比和揭示同一窖池酒醅和窖泥中乳酸菌群落的结构差异和演替规律,并运用BugBase预测酒醅和窖泥乳酸菌群落主要表型的差异.结果显示,窖池中共检出6科16属乳酸菌.酒醅发酵过程中乳酸菌平均丰度为65.21%±29.47%,而窖泥中乳酸菌仅占细菌总量的4.06%±4.24%. 0-3 d酒醅中优势乳酸菌是乳杆菌属(Lactobacillus,占乳酸菌丰度44.01%)、魏氏菌属(Weissella,27.33%),其后乳杆菌属丰度维持在91.06%以上,窖泥中优势乳酸菌为乳杆菌属(95.67%±9.17%). OTU0和OTU3是窖池中乳杆菌属的优势物种,其丰度占乳酸菌总量的76.08%±29.21%.酒醅与窖泥乳酸菌需氧类型不同,发酵初期(0-5 d)的酒醅中好氧乳酸菌相对丰度显著高于后期酒醅和窖泥样品(P 0.01),窖泥中兼性厌氧乳酸菌的丰度高于酒醅样品.综上所述,酒醅和窖泥中乳酸菌群落存在时空异质性,可能影响酒醅和窖泥对泸型酒风味的贡献.(图4参34)     

不同培养条件对罗非鱼肠道乳酸菌分离的影响

为了解罗非鱼肠道乳酸菌群多样性和优势菌种,促进乳酸菌在罗非鱼养殖中的应用,采用MRS、M17、TPY、Elliker四种培养基,分别在有氧、厌氧以及30℃、37℃和45℃温度条件下分离罗非鱼肠道乳酸菌,分析不同培养基、培养温度、有氧和厌氧条件对罗非鱼肠道乳酸菌分离的影响;并对分离到的菌株进行分子鉴定和16S r RNA序列分析,构建系统发育树,比较不同分离条件下分离肠道乳酸菌的遗传多样性.结果表明,不同培养基对罗非鱼肠道乳酸菌的分离效果有一定的差异,其中MRS培养基的分离效果最好,且遗传多样性最高;37℃较30℃对乳酸菌的分离更加有利,45℃未分离到乳酸菌;有氧条件下共分离出8种33株乳酸菌,主要为杆菌;厌氧条件下得到10种24株乳酸菌,主要为球菌.共分离到植物乳杆菌(Lactobacillus plantarum)29株,可能是罗非鱼肠道优势乳酸菌种.本研究可为开发水产养殖肠道乳酸菌提供依据,并推广到其他种类的鱼肠道乳酸菌的分离和鉴定.     

根际微生物耦合降解系统的构建及其对蒽污染土壤的修复

摘要将增强型绿色荧光蛋白(EGFP)标记的黄麻土生根际优势菌Tu-1B分别与葸高效降解菌An-2和生物表面活性剂产生菌P7-50进行原生质体电融合，得到两株具有荧光标记的融合子Tu-An和Tu-P．将二融合子接种于植物根际土壤，构建根际微生物耦合降解系统，：在40d时该系统的最大降解率为96％．对根际土壤中的Tu-An融合子进行了检测，结果表明融合子在根际能稳定旺盛生长．图3表4参18     

浓香型白酒中优势乳酸菌和酵母菌间的相互关系

为了更深入地认识白酒发酵机理,探究多粮浓香型白酒中优势乳酸菌和优势酵母菌的相互作用关系及代谢模型,利用五粮粉为培养基,测定分离自酒醅中的2株优势乳酸菌和2株优势酵母菌纯培养及其共培养中菌株的理化指标、活菌数以及主要挥发性代谢产物的变化.结果显示,Saccharomyces cerevisiae J7产乙醇(56.7 g/L)和酯类物质多,Lactobacillus buchneri R62和Lactobacillus acetotolerans R73产乳酸较多,峰值分别达到11.79和11.64 g/L;共培养时,S.cerevisiae J7显著抑制两株乳酸菌的生长和乳酸合成;两株乳酸菌对Pichia membranifaciens J42的生长和乙醇合成有抑制作用;从挥发性代谢产物可知,P.membranifaciens S42与乳酸菌共培养时,乳酸乙酯含量显著增加.本研究表明浓香型白酒酒醅中的乳酸菌和酵母菌存在相互作用,并且共培养时生成了乳酸乙酯;结果可为白酒发酵提供理论基础.(图5表2参22)     

麻疯树叶绿体ω3脂肪酸脱饱和酶基因的克隆和鉴定

根据几个已知的植物ω3脂肪酸脱饱和酶基因序列,利用RT-PCR和RACE技术从麻疯树中克隆了一条编码叶绿体ω3脂肪酸脱饱和酶的cDNA序列．对该序列的分析表明,该cDNA的编码区长1368bp,编码一个长度为455个氨基酸的蛋白质,推测的蛋白质相对分子质量（Mr）大小为52．1×10^3．同源分析显示,推测的氨基酸序列与其他植物叶绿体脂肪酸脱饱和酶具有很高的相似性．RT-PCR分析表明,该基因在麻疯树叶片中有着稳定的表达．此外,还通过酵母表达系统鉴定了该基因编码的酶的功能．对转基因酵母的脂肪酸组成分析发现,α亚麻酸在转基因酵母中积累．上述结果表明,该麻疯树cDNA编码了一个叶绿体ω3脂肪酸脱饱和酶．图4表2参21     

褐牙鲆白化相关基Nzfp123的组织表达谱与蛋白结构分析

C2H2锌指是真核细胞中最常见的DNA结合模体．对通过mRNA差异显示技术和克隆测序，在褐牙鲆中获得的一条白化相关锌指蛋白基因zfp123，进行了电子表达谱与实验验证表达谱的比较分析及该蛋白序列的一、二级和三级结构分析．电子表达谱分析分别对与ZFP123有较高同源性的斑马鱼、家鼠和猪的zfand5a（zfp123）基因各个组织表达情况进行了比较分析；一、二级结构分析发现其具有多个保守的基序和结构域；同源建模显示其具有一个“C-X（2-4）、-C-X11-C-X2-C”结构的锌指样三级结构．ZFP可以介导靶基因的转录调控，抑制或激活特定基因的表达；对DNA进行修饰，如人造限制性内切酶、重组酶、抗病毒感染等．锌指蛋白应用前景广阔，研究价值显著，是未来基因治疗的革命性的工具．图2表1参21     

地衣芽孢杆菌Lan群体感应系统挖掘及鉴定

地衣芽孢杆菌（Bacillus licheniformis）是一种重要的工业菌株，但目前研究或生产中均主要应用野生型及其传统诱变衍生菌株，对调控认识不足和标准化生物元件缺乏严重限制了该菌株应用的拓展.为开发地衣芽孢杆菌新型调控、表达元件,本研究挖掘地衣芽孢杆菌内源群体感应（quorum sensing,QS）系统Lan QS系统，以荧光蛋白作为报告基因研究转录表达特性，并利用细胞密度无关的组成型启动子鉴定基因簇中调控元件功能.结果表明，lan基因簇与已报道的Agr QS系统具有一定同源性，lanC、lanA、lanB在16 h达到一定细胞密度后开启表达.其下游元件Ptr1启动子具有前期（5 h）表达极弱、后期（48 h）表达脉冲型增长的特性，荧光强度最高可达组成型强启动子Pshuttle-09的30倍；同时，Ptr1的表达依赖胞外信号分子，去除原有培养基后，后期（48 h）Ptr1荧光强度降为对照的30%. lanCBDA完整基因簇、lanC、lanBD和lanA的表达均使Ptr1高表达时期提前，其中lanC、lanA的效应最显著.综上所述，Lan QS系统为地衣芽孢杆菌内源QS系统，...     

阿特拉津在土壤中的生物降解研究

运用恒温培养法研究了阿特拉津在河北省白洋淀地区农田土壤中的生物降解动力学，并从中分离鉴定了土壤中降解阿特拉津的优势菌种，研究结果表明，该土壤对阿特拉津具有一定的降解能力，非生物＋生物的降解、非生物降解和生物降解的速率分别为０．０２６２ｄ＾－１，０．００５５４８ｄ＾－１和０．００８１９４ｄ＾－１，半衰期分别为２６ｄ，１２５ｄ和８５ｄ，发现土壤中降解阿特拉津的优势菌种为蜡状芽孢杆菌（Ｂａｃｉｌｌｕｓ     

高等植物线粒体基因组研究新进展

与其它真核生物相比，高等植物线粒体基因组不仅在大小，组织结构．基因组成和表达，RNA编辑等方面具有突出特点，而且线粒体基因组与核基因组之间存在着广泛的信息交流线粒体基因组作为一个半自主性的遗传系统，其组织结构的雏持和生理功能的发挥受到核基因组的调控作用，本文就这些方面的研究进展作了简要评述．     

尾菜中一株抗生素和铅交叉抗性乳酸菌的筛选及抗性特征

为探究尾菜表面附着的乳酸菌在重金属和抗生素协同选择下的抗性能力,以青菜尾菜为原料评价尾菜表面乳酸菌的环境安全性.通过纯培养方法对青菜尾菜中的乳酸菌进行分离,并对分离菌株进行庆大霉素、土霉素、环丙沙星、氯霉素、青霉素及磺胺间甲氧嘧啶和铅离子(Pb~(2+))的抗性能力测定.结果显示,从青菜尾菜中分离得到50株乳酸菌,有15株对上述供测抗生素均表现出抗性,10株对Pb~(2+)有抗性.其中菌株Lab99对Pb~(2+)的最低抑菌浓度(Minimum inhibitory concentration,MIC)值达到6 000 mg/L,对庆大霉素、青霉素和磺胺间甲氧嘧啶的MIC值均达到320 mg/L以上.另外,该菌株对Pb~(2+)和庆大霉素、磺胺间甲氧嘧啶、土霉素、氯霉素均具有交叉抗性.系统发育分析显示该菌在分类属于粪肠球菌(Enterococcus faecium).本研究表明青菜尾菜上具有对Pb~(2+)和抗生素有交叉抗性的乳酸菌菌株,结果可为重金属和抗生素交叉污染的环境修复治理提供科学依据.(图4表2参38)     

丝状真菌基因功能研究的方法

近年来不少丝状真菌全基因组测序已完成或正在进行,基因功能研究成为真菌研究的一个热点.多种基因功能研究方法都已应用到丝状真菌领域,为丝状真菌的基因功能研究提供了许多不同的技术策略.本文总结了目前丝状真菌基因功能研究中常用的方法,如转座子标签法、基因敲除技术、RNA干扰、超表达及酵母杂交系统等,并对各方法在丝状真菌研究中的优缺点进行了阐述.参42     

Molecular markers of heavy metal toxicity--a new paradigm for health risk assessment

Last decade has witnessed increased interest in studies dealing with molecular markers of health and disease expression of genes. Specific toxicant "signatures" have been detected using genome base technologies such as microarrays. Further toxins have been classified on the basis of these signatures. Knowledge on these signatures has helped in the identification of novel drug candidates. This review discusses the gene expression studies recently made on arsenic, cadmium, mercury, chromium, lead, copper, nickel, manganese, and other essential elements. Toxicogenomics standards and their organizations have also been briefly described. Although this information can not be considered as complete, recent reports from different laboratories on bacteria, fish, laboratory animals and humans have been summarized. It is expected that toxicogenomics data presented in this review will be helpful in planning and excretion of human health risk assessment programs.     

Okadaic acid: a potential defense molecule for the sponge <Emphasis Type="Italic">Suberites domuncula</Emphasis>

Sponges are sessile filter feeders that are exposed to toxic compounds/xenobiotics and a huge number of diverse pro- and eukaryotic organisms occurring in the aqueous milieu. To cope with these threats, sponges have developed a variety of chemical and immunological defense systems. Among them are potent secondary metabolites or toxins. The demosponge Suberites domuncula contains the bioactive compound okadaic acid; concentrations of ᅢ ng/g (ᅬ nM) of wet tissue have been quantified by LC/MS. In the present study, we sought to determine whether okadaic acid is beneficial for this sponge. Antibodies were raised against okadaic acid and used to localize this compound in situ. It could be demonstrated that the polyclonal antibodies/antiserum stained the sponge cells (endopinacocytes) which form the epithelium of the lacunae and the water channels. They also reacted with bacteria present in sponge tissue. Okadaic acid was found to augment the immune response of S. domuncula against the bacterial endotoxin lipopolysaccharide (LPS). If primmorphs, a special form of 3-D aggregates, are incubated with LPS at a concentration of 3 µg/ml, a reduction in the incorporation rate of [³H] phenylalanine is measured. In the presence of okadaic acid, this effect is measured already at a concentration of 1 µg/ml, suggesting that okadaic acid sensitizes this (immune) response. Okadaic acid is a known inhibitor of protein phosphatases which, as shown here, cause an increased phosphorylation of p38, a central kinase of the MAP kinase pathway; this may explain the sensitive response of the sponge cells to LPS. At higher concentrations, okadaic acid induces apoptosis, as was demonstrated here by a differential expression of the Bcl-2 homolog and the caspase gene. It is concluded that okadaic acid has two functions in the sponge; first, at low concentrations (<100 nM) a stimulation of the defense system against bacteria, and second, at concentrations above 500 nM, a differential effect on the pro-/anti-apoptotic genes.     

Natural nutraceuticals for enhancing yogurt properties: a review

Environmental Chemistry Letters - Yogurt is a major fermented milk product providing probiotics, lactic acid bacteria, vitamins, calcium, and proteins, yet health-beneficial phenolics, flavonoids,...     

邻苯二甲酸酯降解细菌的多样性、降解机理及环境应用

邻苯二甲酸酯(phthalic acid esters,PAEs)是一类对人体内分泌系统有干扰作用的持续性有机污染物(persistent organic pol utants,POPs)。PAEs在环境介质如水体、底泥和土壤中长期赋存会对生物体产生毒害效应,其分布广、浓度高和难降解等特点是限制有效环境治理的主要因素。作为环境的重要组成部分,微生物对污染物有很强的适应能力和高效的降解能力,这为PAEs的生物修复提供了可能。与物理化学修复法相比,微生物修复技术具有可控性强、修复面广和灵活性高等优势。本文综述了已报道的大部分PAEs降解细菌的种类及其代谢机制,并分析了其在PAEs污染水体和土壤修复中的应用现状与前景,以期为PAEs环境行为与生物修复研究提供参考。     

Solid substrate fermentation of cassava fibrous residue for production of alpha-amylase, lactic acid and ethanol

There is serious concern about the disposal of solid residues left after large scale extraction of starch from cassava. Owing to the high starch content (55-65% on dry weight basis) and organic matter of these wastes, an attempt has been made to utilize it for the production of three bioproducts, i.e. alpha-amylase, lactic acid and ethanol in solid substrate fermentation by incubating the solid residue at different moisture holding capacity (40-80%) and incubation period (12- 60 hr for alpha-amylase, 24-144 hr for ethanol and 2-10 days for lactic acid). The highest product yield was obtained at 60% moisture holding capacity of the residue and period of incubation varied from 36 hr (alpha-amylase), 120 hr (ethanol) to 6 days (lactic acid). This study showed that the solid residues from cassava starch factories could serve as a low-cost substrate for bioproducts production.     

The microbiological control of mine waste pollution

The removal of heavy metals and neutralisation of acidity in mine waste waters by algae and bacteria are reviewed. Algal growths in artificial meander systems have been shown to remove significant quantities of heavy metals and fine particulates from mine waste waters. Bacterial systems for the oxidation of ferrous iron and the reduction of sulphate leading to neutralisation of acidity are described. The use of bacterial extracellular polymers in the removal of heavy metals from solution is discussed with reference to its application to acid mine waters. It is concluded that a combination of bacterial and algal systems with process optimisation, including nutrient amendment, may provide suitable treatment for mine waste waters. Metal-resistant bacteria may also be important in reclamation, where it is possible that they can confer some degree of tolerance on the plants used to revegetate metal-contaminated tailings dumps.     

Bacteriophages in water pollution control: Advantages and limitations

•Phages can be better indicators of enteric viruses than fecal indicator bacteria. •Multiple phages should be added to the microbial source tracking toolbox. •Engineered phage or phage cocktail can effectively target resistant bacteria. •In phage use, phage-mediated horizontal gene transfer cannot be ignored. •More schemes are needed to prevent phage concentration from decreasing. Wastewater is a breeding ground for many pathogens, which may pose a threat to human health through various water transmission pathways. Therefore, a simple and effective method is urgently required to monitor and treat wastewater. As bacterial viruses, bacteriophages (phages) are the most widely distributed and abundant organisms in the biosphere. Owing to their capacity to specifically infect bacterial hosts, they have recently been used as novel tools in water pollution control. The purpose of this review is to summarize and evaluate the roles of phages in monitoring pathogens, tracking pollution sources, treating pathogenic bacteria, infecting bloom-forming cyanobacteria, and controlling bulking sludge and biofilm pollution in wastewater treatment systems. We also discuss the limitations of phage usage in water pollution control, including phage-mediated horizontal gene transfer, the evolution of bacterial resistance, and phage concentration decrease. This review provides an integrated outlook on the use of phages in water pollution control.     

群体感应现象及其在生物膜法水处理中的应用

群体感应是指细菌通过感知分泌到环境中自诱导物浓度的变化来调整基因表达,增强其在复杂环境中的生存能力,是细菌行为社会化的体现.研究者对群体感应的微生态凋控机制进行了深入的探讨,包括自诱导物的合成、运输和对目的基因的表达调控,以及各信号通路之间的竞争关系对细菌适应环境的影响.本文分析了当前相关研究中的热点问题,提出了群体感应机制在生物法水处理领域中的潜在应用方式.图2参32     

Microbes to clean indoor pollutants

Formaldehyde is a dangerous indoor pollutant which is introduced in house by common objects such as furniture. Effective microorganisms have the very interesting ability to degrade some pollutants. Here, we tested the removal of formaldehyde and aromatic aldehydes using effective microorganisms including yeast, lactic acid bacteria, and photosynthetic bacteria. Formaldehyde was quantified by GC–MS of formaldehyde dinitrophenylhydrazone. Other aldehydes were analyzed by GC–MS. Results show that effective microorganisms remove 70–100 % of formaldehyde, benzaldehyde, and 4-methylbenzaldehyde in about a week. Experiments on chipboard panels indicate the possibility to decrease the amount of formaldehyde emission by furniture. This is the first report on the removal of formaldehyde by effective microorganisms, to our best knowledge.