Bacterial interactions with silver

Summary This review examines interactions between bacteria and the biologically non-essential metal, silver. Aspects of silver toxicity, tolerance and accumulation (possible binding and uptake as opposed to energy-dependent transport) in bacteria are discussed. In addition, plasmid biology is examined briefly since little information is available on the exact mechanism(s) of plasmid-endoced silver resistance in bacteria.     

Bacterial interactions with chromate

Hexavalent chromium compounds (chromates and dichromates) are highly toxic and are considered as mutagens and carcinogens. These compounds are discharged frequently to the environment as a result of diverse industrial processes. Some microorganisms are able to reduce hexavalent chromium to the less toxic trivalent form. Chromate pollution has promoted the selection of bacterial strains possessing chromate resistance determinants, usually carried by plasmids. Strains combining both abilities, i.e. resistance to and reduction of chromate, are potentially useful for detoxifying chromate polluted waste waters.     

细菌生物被膜对抗生素耐药机制的研究进展

细菌生物被膜引发的感染已成为医院感染的主要原因之一,具有耐药性和难治性的特点,引起了基础和临床研究的极大关注。但是细菌生物被膜对抗生素的耐药机制目前还不十分明确,对近年来生物被膜怎样和为什么会对抗生素如此耐药形成了几种可能机制进行综述。     

Relative Potencies of Different Cytochalasins for the Inhibition of Phagocytosis in Ciliates

Ciliate actins have been reported to exhibit an unusual degree of sequence divergence, within the phylum Ciliophora, and when compared to actins from other organisms. To determine whether these primary structural differences are correlated with pharmacological differences, we investigated the effects of seven cytochalasins on phagocytosis, which has been shown to be actin-dependent in eukaryotic cells. The relative potencies of cytochalasin inhibition of phagocytosis in Spirostomun ambiguum and Paramecium multimicronucleatum were similar. Dihydrocytochalasin B and cytochalasin A were the most potent of the seven cytochalasins in both ciliates, and strongly inhibited phagocytosis at 20-40 μM. Dihydrocytochalasin B was considerably more potent than either cytochalasins B or D, a result unexpected on the basis of reports utilizing other organisms. However, even at concentrations up to 100 μM, dihydrocytochalasin B did not inhibit the rate of Spirostomum defecation. After long-term treatment of Spirostomum with 50 μM dihydrocytochalasin B, the sensitivity of phagocytosis to the drug was reduced. These results indicate that the relative cytochalasin sensitivities of actin-dependent functions in ciliates differ from those of other organisms, and are consistent with the hypothesis that sequence differences might give rise to substantial differences in the pharmacological properties of ciliate actins.     

细菌的群体性行为与耐药

随着抗生素的广泛使用,细菌耐药已经成为一个严重的问题。细菌耐药是一个复杂的过程,涉及宿主、细菌与环境等几个既相互独立又相互作用的因素。很久以来,人们认为细菌以个体为单位进行各种活动,直到发现细菌相互之间也存在联系,才意识到细菌群体对其个体生存的重要性。目前将细菌作为一个群体来研究其耐药行为与机制的研究越来越多,特别是细菌生物膜与细菌程序性死亡两方面受到极大重视。本文综述了细菌生物膜、细菌程序性死亡与耐药相关机制的研究进展。     

培养和非培养法分析冷藏鸡肉胴体中的细菌多样性

运用纯培养和非培养法对冷藏鸡肉胴体上细菌多样性进行了对比研究。采用培养法从鸡肉胴体中初步分离到45株细菌菌株,16S rDNA-ARDRA分析得到9株代表性细菌,其16S rDNA序列系统发育分析表明,这些菌株隶属于Bacillus sp.、Shigella sp.、Pseudomonas sp.、Citrobacter sp.、Klebsiella sp.和Escherichia sp.6个属。16S rDNA-ARDRA联合PAGE和16S rDNA全序列分析的非培养法结果表明,冷藏鸡肉中细菌主要属于Acinetobacter sp.、Bacillus sp.、Acidovorax sp.、Brochothrix thermosphacta、Lactococcus garvieae和Leuconostoc lactis等16个属。非培养法揭示的细菌多样性比培养法丰富,但二者结合使用能让肉品中微生物多样性得到更全面的展示。     

Paramecium calkinsi andP. putrinum (Ciliophora, Protista) harboring alpha-subgroup bacteria in the cytoplasm

Summary New intracellular bacteria were detected in the cytoplasm ofParamecium calkinsi andP. putrinum. Some of the bacteria were not evenly distributed in the cytoplasm of the host but were found in the center of the cell, eventually near the nuclei, but not in the cortex area, whereas another species was found in the cortex area. These peculiarities of intracellular bacteria localization in the host suggest that the conditions in various parts of the cytoplasm favor bacterial maintenance to different extent. Due to the results obtained by transmission electron microscopy and in situ hybridization using appropriate oligonucleotide probes, the bacteria, three or possibly four species, are Gram-negative and belong to the alpha-subgroup of proteobacteria. Bacteria from one stock ofP. calkinsi were found to be infectious for bacteria-free cells ofP. calkinsi andP. nephridiatum.     

细菌耐药影响肠道菌群及其宿主免疫调控

抗生素在养殖业、医疗业及制药业的广泛应用导致环境中的细菌耐药性日益严重,环境中的抗生素及耐药细菌一旦进入人体肠道,将破坏肠道菌群稳态,对人体健康造成威胁,而残存于饮食中的环境污染物则加剧了细菌耐药造成的人体健康影响。文中在总结大量文献的基础上,阐述了细菌耐药对人体和动物肠道菌群的影响机制及其相关的机体免疫调控,以环境中影响人体肠道菌群获得耐药性的来源作为切入点,阐述抗生素和耐药细菌进入人体肠道后对人体肠道菌群结构和耐药基因组成的影响,以及与人体免疫和免疫调节相关疾病之间的相关机制,并对今后的研究方向进行了展望。     

Genetics-squared: combining host and pathogen genetics in the analysis of innate immunity and bacterial virulence

The interaction of bacterial pathogens with their hosts’ innate immune systems can be extremely complex and is often difficult to disentangle experimentally. Using mouse models of bacterial infections, several laboratories have successfully applied genetic approaches to identify novel host genes required for innate immune defense. In addition, a variety of creative bacterial genetic schemes have been developed to identify key bacterial genes involved in triggering or evading host immunity. In cases where both the host and pathogen are amenable to genetic manipulation, a combination of host and pathogen genetic approaches can be used. Focusing on bacterial infections of mice, this review summarizes the benefits and limitations of applying genetic analysis to the study of host–pathogen interactions. In particular, we consider how prokaryotic and eukaryotic genetic strategies can be combined, or “squared,” to yield new insights in host–pathogen biology.     

宜春温泉水体与泉底沉积物细菌多样性分析

研究宜春富硒温泉水体与泉底沉积物的细菌群落多样性。利用高通量测序技术分析泉水与沉积物中细菌群落结构与多样性。温泉水中主要的细菌类群为变形菌门和拟杆菌门,而在沉积物样品中的主要优势菌群为OP1、蓝细菌、浮霉菌门和绿弯菌门。细菌在属分类水平上,温泉水中优势菌群为不动杆菌属、假单胞菌属、水栖菌属、Thermosynechococcus、鞘脂杆菌属和金黄杆菌属等。沉积物样品细菌中优势菌群属于未知物种,在数据库中并没有相关的注释信息;其中已知的优势菌属为Candidatus acetothermum、Thermosynechococcus、亚热栖菌属、不动杆菌属。宜春温汤富硒温泉水体与沉积物中存在着丰富的微生物群落且组成差异性很大,该研究为了解与发掘温泉微生物菌种资源具有重要价值。     

人体泌尿系微生物感染与耐药及宿主状态分析

目的了解泌尿系感染常见病原细菌和真菌分布、耐药性及宿主相关状态,为理解相关微生物感染影响因素及临床合理用药提供资料和依据。方法对门诊及住院患者中段尿培养分离的179株病原细菌和真菌进行微生物学鉴定和K-B法药敏试验,同时记录门诊和住院的菌株相关的泌尿系感染患者情况。结果泌尿系感染微生物以大肠埃希菌居首位,占62.4%,其次为真菌和肠球菌,各占12.4%、14.0%。药敏结果显示,大肠埃希菌产ESBLs占62.2%;肠杆菌科细菌对亚胺培南、美罗培南的敏感率为100%,其次敏感性较好的为氨基糖苷类阿米卡星、头孢头霉类头孢西丁及第三代头孢类头孢哌酮/舒巴坦、头孢他啶,敏感率均大于80%。革兰阳性球菌万古霉素敏感率为100%,对呋喃妥因敏感率为70.8%。大肠埃希菌感染率与患者的身体状态和行为具有显著的相关性(P<0.01)。结论革兰阴性杆菌是泌尿系感染的主要病原菌,机体免疫状态低下、不洁等生活行为与尿路微生物感染密切相关,但与耐药性不相关。维护机体正常免疫力、注意合适的生活行为,对预防泌尿道病原细菌与真菌的感染十分重要。     

Phylogenetic Profiling and Diversity of Bacterial Communities in the Death Valley,an Extreme Habitat in the Atacama Desert

The Atacama Desert, one of the driest deserts in the world, represents a unique extreme environmental ecosystem to explore the bacterial diversity as it is considered to be at the dry limit for life. A 16S rRNA gene (spanning the hyper variable V3 region) library was constructed from an alkaline sample of unvegetated soil at the hyperarid margin in the Atacama Desert. A total of 244 clone sequences were used for MOTHUR analysis, which revealed 20 unique phylotypes or operational taxonomic units (OTUs). V3 region amplicons of the 16S rRNA were suitable for distinguishing the bacterial community to the genus and specie level. We found that all OTUs were affiliated with taxa representative of the Firmicutes phylum. The extremely high abundance of Firmicutes indicated that most bacteria in the soil were spore-forming survivors. In this study we detected a narrower diversity as compared to other ecological studies performed in other areas of the Atacama Desert. The reported genera were Oceanobacillus (representing the 69.5 % of the clones sequenced), Bacillus, Thalassobacillus and Virgibacillus. The present work shows physical and chemical parameters have a prominent impact on the microbial community structure. It constitutes an example of the communities adapted to live in extreme conditions caused by dryness and metal concentrations .

Electronic supplementary material

The online version of this article (doi:10.1007/s12088-015-0539-3) contains supplementary material, which is available to authorized users.     

2013年新疆17家三级医院细菌耐药性监测分析

目的:了解新疆地区17家三级医院2013年临床分离细菌的分布特征及对抗生素的耐药性。方法:采用最小抑菌浓度法(MIC)和纸片扩散法(K-B)对细菌进行药物敏感试验。结果:临床共分离出细菌44022株,其中革兰阳性菌占30.2%,革兰阴性菌占69.8%。1大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌产ESBLs菌株检出率分别为66.2%、48.0%和52.0%。2鲍曼不动杆菌和铜绿假单胞菌对亚胺培南和美洛培南的耐药率分别为51.8%、30.4%和37.6%、22.9%。3耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRSCN)的检出率分别为27.7%和79.8%。414岁以下儿童肺炎链球菌对青霉素的耐药率(4.2%)高于成人(2.1%)。泛耐药菌株(XDR)中,鲍曼不动杆菌381株(9.6%),铜绿假单胞菌57株(1.7%),大肠埃希菌6株(0.1%),肺炎克雷伯菌16株(0.3%)。结论:通过对细菌耐药数据分析情况来看,细菌耐药情况普遍存在,对于耐药克隆株的传播,应加以关注;此外,应加强细菌耐药监测,合理使用抗生素。     

Bacterial species in raw and cured compost from a large-scale urban composter

Summary Raw and cured compost samples from a large-scale urban composter were studied over a period of eight months to gain information on bacterial species present. Total viable, aerobic heterotrophic bacteria, lactose-positive bacteria, antibiotic and metal-resistant bacteria and thermophilic bacteria were enumerated. Both raw and cured compost samples contained metal and antibiotic-tolerant bacteria (–1 compost) as well as high numbers (as high as Log 7.4 CFU g^–1 dry weight compost) of thermophilic bacteria isolated by growth at 55 °C. Selected colonies were also identified using the Biolog 95 substrate identification system.Escherichia coli andSalmonella spp. were not detected in compost samples.     

Phylogenetic relationships of the Subclass Peniculia (Oligohymenophorea, Ciliophora) inferred from small subunit rRNA gene sequences

Peniculine ciliates have been recognized as a distinct higher taxon of ciliates for almost 50 years. However, phylogenetic relationships within the Subclass Peniculia are still unsettled. To contribute to our understanding of their phylogeny and provide evidence for the position of Urocentrum turbo, we sequenced its small subunit (SS) rRNA gene and the SSrRNA genes from Lembadion bullinum, Frontonia sp., Paramecium caudatum, Paramecium multimicronucleatum, Paramecium putrinum, and Paramecium woodruffi. Urocentrum turbo was the only one of these species not to exhibit a shortened Helix E10_1, which we conclude characterizes the "higher" peniculines. Except for U. turbo, the peniculines are strongly supported as a monophyletic clade with Lembadion, Frontonia, and Paramecium species forming separate and strongly supported clades by bootstrap analysis using distance matrix, maximum parsimony, and maximum likelihood methods. Urocentrum turbo is associated with different lineages, depending upon the analysis used. The Paramecium species form at least four clades with the Paramecium aurelia subgroup being the most derived. We conclude that the Subclass Peniculia should be divided into two orders, the Order Urocentrida and Order Peniculida, with the latter order having two suborders, the Suborder Frontoniina and Peniculina. We place U. turbo with the peniculines because of shared morphological and stomatogenetic features.     

花生抗青枯病种质脂肪酸组成的遗传多样性

通过对123份不同类型抗青枯病花生种质种子脂肪酸的鉴定测试,分析了抗青枯病花生种质在这些性状方面的遗传分化,并与6006份资源组成的花生基础收集品进行了比较。研究结果表明,我国抗青枯病花生资源的油酸含量平均为51.78%,显著高于基础收集品的对应值(45.64%);亚油酸含量平均为28.88%,显著低于基础收集品的对应值(34.36%);高油酸种质较多,油酸含量达61%以上的资源23份,所占比重为18.7%,显著高于基础品中的相应比重(2.65%)。标准差、变异系数以及遗传多样性指数的分析结果表明,抗青枯病资源在油酸和亚油酸含量方面的遗传分化程度高。     

A New Tool to Reveal Bacterial Signaling Mechanisms in Antibiotic Treatment and Resistance

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Highlights

• •Quantitative (phospho)proteome analysis of antibiotic treatment in E. coli.
• •Largest bacterial phosphorylation catalogue.
• •Specific phosphorylation motifs changes during resistance development.
• •Phosphorylation mediated signaling could be a potential target for drug design.

     

Diversity of rhizobia and interactions among the host legumes and rhizobial genotypes in an agricultural-forestry ecosystem

To investigate the diversity of rhizobia and interactions among the host legumes and rhizobial genotypes in the same habitat, a total of 97 rhizobial strains isolated from nine legume species grown in an agricultural-forestry ecosystem were identified into seven genomic species and 12 symbiotic genotypes within the genera Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium based upon analyses of genomic DNA regions and symbiotic genes. The results evidenced that the symbiotic genotypes of rhizobia were consistent with their hosts of origin; revealed that vertical transfer was the main mechanism in rhizobia to maintain the symbiotic genes but lateral transfer of symbiotic genes might have happened between the closely related rhizobial species; suggested the existence of co-distribution and co-evolution among the legume hosts and compatible rhizobia. All of these data demonstrated that the biogeography of rhizobia was a result of interactions among the host legumes, bacterial genomic backgrounds and environments.