Bacterial disease resistance in Arabidopsis through flagellin perception

Plants and animals recognize microbial invaders by detecting pathogen-associated molecular patterns (PAMPs) such as flagellin. However, the importance of flagellin perception for disease resistance has, until now, not been demonstrated. Here we show that treatment of plants with flg22, a peptide representing the elicitor-active epitope of flagellin, induces the expression of numerous defence-related genes and triggers resistance to pathogenic bacteria in wild-type plants, but not in plants carrying mutations in the flagellin receptor gene FLS2. This induced resistance seems to be independent of salicylic acid, jasmonic acid and ethylene signalling. Wild-type and fls2 mutants both display enhanced resistance when treated with crude bacterial extracts, even devoid of elicitor-active flagellin, indicating the existence of functional perception systems for PAMPs other than flagellin. Although fls2 mutant plants are as susceptible as the wild type when bacteria are infiltrated into leaves, they are more susceptible to the pathogen Pseudomonas syringae pv. tomato DC3000 when it is sprayed on the leaf surface. Thus, flagellin perception restricts bacterial invasion, probably at an early step, and contributes to the plant's disease resistance.     

5种药用植物内生真菌的分离及其抑菌活性的研究

从樟树、女贞、十大功劳、绞股蓝及荔枝草的叶片、叶柄、茎和枝条等部位分离内生真菌,并以金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、绿脓杆菌为试验菌对分离的内生真菌进行了抑菌活性筛选.结果从5种药用植物中共分离出124株内生真菌,其中37株内生真菌对一种或多种供试菌有抑制作用,高抗菌活性菌株有11株.     

混凝沉淀-超滤-消毒组合工艺对二级出水中条件致病菌的去除效能及风险评价

再生水回用是解决水资源危机的重要途径,但污水厂二级出水中存在的大量条件致病菌,会对人体健康构成潜在风险。本研究采用混凝沉淀-UF-NaClO消毒组合工艺作为二级出水的深度处理工艺,探究该组合工艺对条件致病菌（军团菌、铜绿假单胞菌、鸟分支杆菌）和大肠杆菌的去除效能,并以再生水景观回用（划船游湖、孩童玩水、叠水花台观赏）作为评价场景,对条件致病菌进行健康风险评价和参数不确定性因素的敏感性分析。结果表明,混凝沉淀-UF-NaClO消毒组合工艺对水中三种条件致病菌及大肠杆菌的去除效果较好,去除率均能达到98%以上,但出水中的大肠杆菌浓度与三种条件致病菌之间不存在显著相关性,其含量不能够完全地指示三种条件致病菌的含量。二级出水经组合工艺处理后回用于城市景观休闲活动中,三种条件致病菌的单次感染概率较低,对人体健康的安全保障率可达70.9%~100.0%。敏感性分析结果表明：三种暴露途径中感染军团菌和鸟分支杆菌的年健康风险值均受年暴露频率f的不确定性影响最大;划船游湖、孩童玩水两种暴露途径中感染铜绿假单胞菌的年风险值受暴露体积v和铜绿假单胞菌浓度值C的不确定性影响较大。综上,混凝沉淀-UF-NaClO组合工艺可有效控制二级出水中的条件致病菌的浓度,回用于景观休闲活动中的微生物健康风险较低。     

7株处理印染废水细菌的分离及鉴定

从福建石狮锦尚和伍堡污水处理厂的曝气池活性污泥中分离筛选到对碱性孔雀绿染料脱色能力强的7株高效菌株(B1、B2、B3、B4、B5、B6、B7),并对7株细菌进行鉴定:B1菌株为库特氏菌属(Kurthia),B2菌株为假单胞菌属(Pseudomonas),B3菌株为色杆菌属(Chromobacterium),B4菌株为气单胞菌属(Aeromonas),B5菌株为节杆菌属(Arthobacter),B6菌株为氧化产碱菌属(Alealigenes),B7菌株为棒状菌属(Corynebacterium).     

Biodegradation of the Oil Hydrocarbons in Wastewater with Immobilized Microbiological Activated Carbon

On the basis of laboratory-scale-tests, the method of using immobilized biological activated carbon (IBAC) was found to be an efficient method to treat oil wastewater. In this research, pilot-scale studies were conducted to investigate the optimal range of factors, such as oil concentration, and hydraulic retention time (HRT). 39 strains of bacteria were isolated from activated sludge of a petrochemical wastewater treatment plant. After being acclimated and identified, these bacteria were immobilized on granular activated carbon. The degradation of organic compounds was analyzed by gas chromatography-mass spectromtry(GC-MS). As the results show that when the oil concentration is lower than 50 mg/L and corresponding values of HRT are longer than 1.0 h, the removal rate of immobilized biological activated carbon column can stably reach at least 70%. In the field studies, electron microscope analyses show that the predominant bacteria have been changed from Pseudomonas and Bacillus at the beginning to Bacillus only after 60 days of continuous operation, which suggests that the method with immobilized biological activated carbon column is the one with higher efficiency than that of the secondary floatation tank traditionally used in oil wastewater treatment.     

植物病原细菌应急反应研究进展

细菌生活在营养匮乏的环境时,为了能够适应这种恶劣的环境,细菌自身会产生应急反应。细菌的应急反应至今仍是生物学研究热点之一,实施这一应急反应的是胞内的信号分子(p)ppGpp,其能与RNA聚合酶结合,调控许多细胞过程,包括病原细菌致病过程,可以作为防治动植物细菌性病害的药物靶点。植物病原细菌分布范围很广,能引起植物的许多重要病害发生,对许多农作物造成了重大经济损失。本文综述了植物病原细菌解淀粉欧文氏菌(Erwinia amylovora)、丁香假单胞杆菌(Pseudomonas syringae)、黑腐果胶杆菌(Pectobacterium atrosepticum)、柑橘黄单胞菌柑橘亚种(Xanthomonas citri subsp.citri)和十字花科黑腐病菌(X.campestris pv.campestris,Xcc)中应急反应的研究进展,为全面、深入地了解植物病原细菌的应急反应,有效防治植物细菌性病害提供参考。     

荧光假单胞菌的应用与展望

植物根际促生菌(PGPR)中的荧光假单胞菌(Pseudomonas fluorescens)对植物病原体具有潜在的拮抗作用,同时具有促进植物生长的能力.阐述了荧光假单胞菌在实际生产中的应用潜力.荧光假单胞菌可以通过产生生长素,增强土壤中磷、钾的可用性,促进植物叶绿素含量的增加,及产生谷胱甘肽、ACC脱氨酶等形式促进植物的生长.通过产抗生素(吩嗪、2,4-二乙酰基间苯三酚、藤黄绿脓菌素、硝吡咯菌素)、拮抗线虫等方式帮助植物体抵抗病虫害的侵袭.除此之外,荧光假单胞菌所具有的定殖与产铁载体能力在植物的促生与抗病方面皆发挥着重要作用.荧光假单胞菌在农业生产方面具有巨大的应用潜力.     

陆梁油田菌群结构解析及激活后群落变化

 针对新疆陆梁油田呼图壁河组注水井LU3064 注入水,设计一组营养剂激活配方,该配方能够成功乳化原油。经平板计数法、最大或然数计数法（MPN）和理化性质检测发现,激活后注入水菌浓明显增加,表面张力下降37%。采用建立细菌16S rDNA克隆文库方法,对LU3064 注入水、LU3036 采出液、LU3064 激活液细菌进行多样性研究。从克隆文库中随机挑选100 个克隆子测序,并在GenBank 中比对,结果表明,注入水菌群具有高度多样性,优势菌属于Alphaproteobacteria;采出液较地层水菌群结构简单,存在Pseudomonas（假单胞菌属）、Bacillus（芽孢杆菌属）等功能菌属;激活液菌群结构最为单一,仅存在Bacillus（芽孢杆菌属）。Bacillus 在注入水和采出液中均有发现,但都不是优势菌种。该激活剂配方成功激活了可在地层中生长的功能菌属Bacillus。     

Isochorismate synthase is required to synthesize salicylic acid for plant defence.

Salicylic acid (SA) mediates plant defences against pathogens, accumulating in both infected and distal leaves in response to pathogen attack. Pathogenesis-related gene expression and the synthesis of defensive compounds associated with both local and systemic acquired resistance (LAR and SAR) in plants require SA. In Arabidopsis, exogenous application of SA suffices to establish SAR, resulting in enhanced resistance to a variety of pathogens. However, despite its importance in plant defence against pathogens, SA biosynthesis is not well defined. Previous work has suggested that plants synthesize SA from phenylalanine; however, SA could still be produced when this pathway was inhibited, and the specific activity of radiolabelled SA in feeding experiments was often lower than expected. Some bacteria such as Pseudomonas aeruginosa synthesize SA using isochorismate synthase (ICS) and pyruvate lyase. Here we show, by cloning and characterizing an Arabidopsis defence-related gene (SID2) defined by mutation, that SA is synthesized from chorismate by means of ICS, and that SA made by this pathway is required for LAR and SAR responses.     

Do anogenital gland secretions of giant panda code for their sexual ability？

Communication and social recognition in many mammals are based on olfactory signals[1―3]. In many taxonomic groups, odors provide cues to species iden- tity, reproductive status, genetic relatedness and indi- vidual identity including social status[4,5].…     

Bacteriophytochromes are photochromic histidine kinases using a biliverdin chromophore.

Phytochromes comprise a principal family of red/far-red light sensors in plants. Although phytochromes were thought originally to be confined to photosynthetic organisms, we have recently detected phytochrome-like proteins in two heterotrophic eubacteria, Deinococcus radiodurans and Pseudomonas aeruginosa. Here we show that these form part of a widespread family of bacteriophytochromes (BphPs) with homology to two-component sensor histidine kinases. Whereas plant phytochromes use phytochromobilin as the chromophore, BphPs assemble with biliverdin, an immediate breakdown product of haem, to generate photochromic kinases that are modulated by red and far-red light. In some cases, a unique haem oxygenase responsible for the synthesis of biliverdin is part of the BphP operon. Co-expression of this oxygenase with a BphP apoprotein and a haem source is sufficient to assemble holo-BphP in vivo. Both their presence in many diverse bacteria and their simplified assembly with biliverdin suggest that BphPs are the progenitors of phytochrome-type photoreceptors.     

AISI 4340钢马氏体相变的研究

采用膨胀法对AISI 4340钢在900~1 150℃几种不同温度下进行奥氏体化,以得到不同的奥氏体晶粒度(AGS),然后快速冷却到室温,得到马氏体组织.实验结果表明:奥氏体晶粒度和晶界析出相对马氏体相变动力学,尤其是马氏体转变温度(tms)产生很大影响.总的趋势是AGS越大,tms越高.在不同的奥氏体化温度段,会有不同的C,N化合物析出,对马氏体形核产生影响.在奥氏体化温度低于1 000℃时,AGS增大,tms快速增加.其原因主要是由于AlN等晶界析出相对马氏体形核的促进作用.在奥氏体化温度高于1 050℃时,tms随AGS增大而升高,这是因为TiC等溶解温度较高的化合物在晶界析出对马氏体形...     

花生固氮根瘤菌应用研究

应用花生固氮根瘤菌，通过拌种方法在花生种子中接种，种植在未种过花生的花岗岩发育的壤土中，进行固氮效果测定。结果表明，施用的花生固氮根瘤菌明显增加了花生的结瘤量，植株生长健壮，群体生长旺盛，增加植株生物量，结荚率提高11%，植株含氮量提高52.9%，籽仁含氮量提高52.5%，产量提高40%，增产效果显著。     

內源微生物驱后油藏理化性质变化及细菌群落结构解析?

通过研究新疆油田微生物驱后油水两相理化性质,发现现场注入营养剂后采出液水相黏度升高50%以上,油相黏度降低54%,油水两相界面张力降低了24%。通过比较两种细胞破碎方法提取的采出水中细菌总DNA质量,确定使用以超声波细胞破碎法所提取的水样总DNA扩增细菌16S rDNA高可变区V9区,利用变性梯度凝胶电泳（Denaturing Gradient Gel Electrophoresis,DGGE）法根据DNA片段裂解性质分析不同时期采出水菌群变化。通过对优势条带序列的分析及在GenBank中的比对,发现现场营养剂激活后菌群构成趋向简单化,激活后微生物采油常用功能菌假单胞菌属（Pseudomonas）和梭菌(Clostridium)为优势菌。说明通过现场营养剂的注入,定向激活了有益功能菌,改善了油藏油水流度比,这些都是油田现场采收率提高的原因。     

除油好氧降解菌的筛选与除油效果初探

为筛选降解含油废水中石油烃的好氧降解菌株,选用炼油厂石油废水处理站曝气池活性污泥作为菌源,采用平板分离,得到39株菌。利用得到的菌株对含油废水中的CODCr和油进行降解效果试验,并进行混合菌的联合试验,确定出混合菌中假单胞菌(Pseudomonas sp)和芽孢杆菌(Bacillus sp)为优势菌属。通过单株菌与混合菌降解试验的比较,结果表明全混合菌的降解效果明显优于单株菌,从而说明共代谢作用增强了微生物的降解能力。试验表明,经过驯化后的混合菌,其降解效率稳定。     

菌丝内生细菌及其宿主真菌共生体系研究进展

微生物共生普遍存在于自然界中，真菌-细菌联合体能以多种方式相互作用，共同发挥各种生态功能。有些细菌驻留在真菌菌丝内部，借以调控真菌的生长、发育、分布和次级代谢过程，这些细菌被称为菌丝内生细菌（endohyphal bacteria, EHB）。EHB的研究揭开了微生物生态学的一个新篇章，是真菌与细菌共生关系中最紧密的代表。在逆境条件下，EHB可以调节寄主生殖机制相关的关键成分或步骤，诱导植物激素类物质的产生，对寄主真菌具有辅助性保护作用。研究最深入的真菌-EHB共生体系是植物致病性根霉菌Rhizopus sp.与伯克霍尔德氏菌Burkholderia sp.，引起水稻幼苗枯萎病所必需的植物毒素——根霉素是由伯克霍尔德氏菌所产生的，而非寄主根霉菌本身产生的。EHB也会影响定殖于高等植物的内生真菌的生态和多样性。在某些情况下，EHB还有助于激活参与识别、转录调节和初级代谢蛋白合成过程的相关基因。目前已开发出了无菌培养分离EHB的方法，然而对真菌-EHB共生体系的研究尚不够深入。综述了菌丝内生细菌EHB及其与宿主真菌的共生体系，阐述这些伴侣之间复杂微妙的相互关系，以及EHB对宿主真菌和宿主植物生长和发育的影响，并对该领域的研究方向提出了建议。     

菌丝内生细菌及其宿主真菌共生体系研究进展

微生物共生普遍存在于自然界中，真菌-细菌联合体能以多种方式相互作用，共同发挥各种生态功能。有些细菌驻留在真菌菌丝内部，借以调控真菌的生长、发育、分布和次级代谢过程，这些细菌被称为菌丝内生细菌（endohyphal bacteria, EHB）。EHB的研究揭开了微生物生态学的一个新篇章，是真菌与细菌共生关系中最紧密的代表。在逆境条件下，EHB可以调节寄主生殖机制相关的关键成分或步骤，诱导植物激素类物质的产生，对寄主真菌具有辅助性保护作用。研究最深入的真菌-EHB共生体系是植物致病性根霉菌Rhizopus sp.与伯克霍尔德氏菌Burkholderia sp.，引起水稻幼苗枯萎病所必需的植物毒素——根霉素是由伯克霍尔德氏菌所产生的，而非寄主根霉菌本身产生的。EHB也会影响定殖于高等植物的内生真菌的生态和多样性。在某些情况下，EHB还有助于激活参与识别、转录调节和初级代谢蛋白合成过程的相关基因。目前已开发出了无菌培养分离EHB的方法，然而对真菌-EHB共生体系的研究尚不够深入。综述了菌丝内生细菌EHB及其与宿主真菌的共生体系，阐述这些伴侣之间复杂微妙的相互关系，以及EHB对宿主真菌和宿主植物生长和发育的影响，并对该领域的研究方向提出了建议。     

堆肥微生物产生的生物表面活性剂的提纯表征

从堆肥中筛选产生生物表面活性剂的菌种,然后对筛选得到的菌种于适宜条件下进行发酵培养,得到生物表面活性剂．同时对生物表面活性剂发酵液进行萃取、柱层析等一系列的分离提纯,得到较纯的生物表面活性剂及一种较好的提纯生物表面活性剂的方法,然后采用液质联用对提纯的生物表面活性剂进行表征,结果表明该堆肥中产生生物表面活性剂的主要菌种为铜绿假单胞菌,其产生的生物表面活性剂为鼠李糖脂．     

铝离子对低温好氧颗粒污泥颗粒化的强化作用

研究了低温条件下Al 3+对好氧颗粒污泥颗粒化的强化作用.在Al 3+质量浓度为30.0mg.L-1条件下,经强化颗粒化作用的好氧颗粒污泥仅需40d即可以培养成熟,其表面光滑,结构紧密,具有较好的沉淀性能和较高的生物量.培养成熟的低温好氧颗粒污泥对污水具有较高的处理效能,COD,NH4+-N和PO34--P去除率分别达到85.6%,88.8%和91.9%,较好地实现了碳氮磷的低温高效同步去除.低温好氧颗粒污泥形成过程中,胞外聚合物中蛋白质类的质量分数明显升高,达到9.25mg.g-1,蛋白质类与多糖类的质量比(PN/PS)为1.10,说明较高含量的蛋白质类是好氧颗粒污泥形成的重要因素.同时,加入30mg.L-1 Al 3+后,污泥zeta电位从-18.40mV逐渐升高到-6.51mV,表明污泥之间静电斥力减小有利于污泥聚集,形成颗粒.