吸烟对人体呼吸道厌氧菌的影响

目的探究吸烟对人体内的呼吸道微生态的影响。方法采用细菌鉴定及药敏分析系统鉴定健康吸烟者与非吸烟者,患下呼吸道感染吸烟与非吸烟者咽后壁分泌物的细菌密度、细菌数量及种类的改变。结果在健康吸烟者与患有下呼吸道感染患者的呼吸道中,厌氧菌明显升高,其中以韦荣菌和消化链球菌为主。结论吸烟可使人体的呼吸道微生态中细菌密度,细菌数量及种类的改变,易患呼吸系统疾病。     

噬菌体与细菌相互作用的分子机制研究进展

噬菌体与细菌是自然界中存在最广泛的两类微生物,两者在群体水平、个体水平以及分子水平上均存在复杂的相互作用关系.细菌能够影响溶原性噬菌体的溶原-裂解决策,而被噬菌体感染的细菌基因表达谱也会受到噬菌体影响,使宿主菌的代谢、应激、抵抗力、毒性等多种性状发生改变.现从细菌和噬菌体两者的角度,分别综述细菌抵抗噬菌体感染以及噬菌体...     

人体共生菌及其抗菌分子研究进展

随着耐药细菌的出现和广泛传播,开发新型抗菌药迫在眉睫。分布在人体不同部位的共生菌能够产生多种抗菌分子以抑制病原菌的定植和感染。人体共生菌的抗菌分子为研发全新结构和作用机制的药物提供了潜在的资源宝库,随着生物信息学、合成生物学、基因组学等组学技术的进一步发展,对人体共生菌抗菌分子的挖掘也会更加深入,为解决耐药问题提供了有效的途径。文中回顾了目前所发现的人体共生菌产生的抗菌分子,并介绍了几种用于挖掘人体共生菌这一天然抗菌药物的资源宝库的方法。随着现代生物工程技术的发展,人体共生菌的抗菌分子将会得到更加全面、系统的探索和应用。     

不同被捕食细菌对新疆盐碱地粘细菌分离的影响

【目的】利用被捕食细菌诱导粘细菌形成子实体的方法分离新疆盐碱地粘细菌,并初步分析被捕食菌与被诱导粘细菌之间关系。【方法】从盐碱地分离出16株对粘细菌具有不同诱导作用的被捕食细菌,将其用以分离新疆阿克苏地区盐碱地粘细菌。【结果】对25个盐碱地土样的粘细菌进行分离,共分离到55株粘细菌,结合分子生物学手段和形态学特征,初步将其归属为粘球菌属、珊瑚球菌属、Pyxidicoccus、孢囊杆菌属和侏囊菌属及6株无法纯化的疑似粘细菌。供试的16株被捕食细菌诱导粘球菌属均具有较好效果,而Pyxidicoccus和孢囊杆菌只能由革兰氏阳性菌诱导。【结论】与传统分离方法比较,采用多种被捕食细菌分离粘细菌其出菌率明显提高,数量增加,且易观察和挑取,有利于后续纯化。不同粘细菌的捕食菌谱及捕食嗜好不同,增加被捕食细菌筛选范围可能会提高粘细菌的分离效率。本研究采用被捕食菌分离粘细菌的方法为粘细菌的分离提供了新思路与途径。     

细菌生物被膜的耐药机制及控制策略

在特定的条件下,细菌可以形成生物被膜,包被有生物被膜的细菌称为被膜菌.被膜菌无论其形态结构、生理生化特性、致病性还是对环境因子的敏感性等都与浮游细菌有显著的不同,尤其对抗生素和宿主免疫系统具有很强的抵抗力,从而导致严重的临床问题,引起许多慢性和难治性感染疾病的反复发作.细菌生物被膜粘附在各种医疗器械及导管上极难清除,以至引发大量的医源性感染.近年来,随着人们对细菌致病机制认识的逐步深入,控制细菌生物被膜的方法已有较大发展.本文拟探讨被膜菌的耐药机制并着重综述细菌生物被膜控制方法的最新研究进展.     

噬菌体及其裂解酶对细菌生物被膜作用的研究进展

细菌形成的生物被膜,可保护细菌不易被抗生素杀死,这给临床上相应疾病的治疗及医疗器械的消毒带来极大困难。研究表明,噬菌体及其裂解酶对生物被膜有降解作用。噬菌体能清除细菌在有生物活性或无生物活性的介质表面形成的生物被膜。此外,噬菌体裂解酶比如LySMP、肽酶CHAPk、细胞壁溶解酶CWHs等能清除特定的生物被膜,这可能与裂解酶直接溶菌和裂解细菌细胞外基质有关。同时,与抗生素、钴离子、氯等物质联合使用时,噬菌体对生物被膜的清除作用会更强。本文从噬菌体、噬菌体编码的裂解酶、以及它们联合其他物质对细菌生物被膜的作用进行综述,并对其实际应用做了展望。     

外源砷胁迫对两种土壤中细菌和古菌群落的影响

采矿和冶炼等活动会导致土壤中砷的累积,给农产品质量安全和土壤微生物带来不利影响。本文研究了外源砷进入黄壤(YS)和紫色砂页岩发育土壤(RS)后有效砷含量随时间的变化,并采用MiSeq高通量测序研究土壤中细菌和古菌在未加砷和外源砷胁迫1、30、360 d后的群落变化,探讨砷胁迫下土壤细菌和古菌的适应机制。结果表明: 外源砷进入土壤后,土壤有效砷含量随时间推移逐渐降低,并显著影响土壤细菌和古菌的群落组成。土壤细菌的优势菌群丰度变化显著;而古菌中仅丰度较低的菌群发生显著改变,优势菌群丰度变化较小,推测古菌群落具有高耐砷性和稳定性。与砷胁迫时间相比,土壤砷的有效性对细菌和古菌群落结构的影响更大。研究结果可为砷污染农田的安全利用及微生物修复等提供参考。     

细菌菌影作为新型疫苗和递送载体的研究进展

细菌菌影（bacterial ghost,BG）是革兰阴性菌在噬菌体PhiX174的裂解基因E的作用下形成不含核酸、核糖体等胞质内容物的细菌空壳。这种细菌空壳保留了与天然细菌一样的完整外膜结构,且不具有活菌样的致病作用,可作为疫苗无需佐剂就能诱导机体产生体液免疫应答和细胞免疫应答。菌影内部及外膜上可装载DNA、抗原和药物等异源物质,易被机体免疫细胞识别捕获,使其成为一种新型的生物递送载体。另外,菌影具有制备简单,易于保存等优点。细菌菌影在疾病预防和治疗方面具有广阔的应用前景。     

鸭疫里默氏杆菌铁离子代谢机制研究进展

铁离子是大多数细菌生存所必需的一种营养物质,但过多的铁离子会通过芬顿反应产生的活性氧对细菌造成损伤。因此,细菌通过摄取、调控、螯合、外排等机制维持体内铁离子的稳态。鸭疫里默氏杆菌(Riemerella anatipestifer)是一种最新被归类于威克斯菌科里氏杆菌属的革兰氏阴性菌。该菌主要感染禽类,参与该菌的铁离子代谢基因具有特别之处。本文对鸭疫里默氏杆菌铁离子代谢机制研究进展进行了系统总结和阐述,包括该菌的TonB系统、TonB依赖性受体、Fur蛋白及Dps蛋白等在铁离子转运、调控、螯合中的功能,以及以上蛋白在鸭疫里默氏杆菌致病中的作用,以期更全面地理解鸭疫里默氏杆菌铁代谢机制,并为进一步深入研究该菌铁离子代谢提供理论依据和参考。     

金双歧治疗功能性便秘临床应用

“口服双歧杆菌、乳杆菌、嗜热链球菌三联活菌片”属于微生态制剂,临床上用于治疗肠道菌群失调引起的腹泻、慢性腹泻、抗生素治疗无效的腹泻及便秘。其药效成分是长双歧杆菌、保加利亚乳杆菌、嗜热链球菌3种健康人体肠道正常生理性细菌,可在人体肠道中生长繁殖。其药理作用是通过直接补充人体正常生理细菌,调整肠道菌群平衡,抑制并清除肠道中对人具有潜在危害的细菌,从而达到治疗腹泻及便秘的目的。“口服双歧杆菌、乳杆菌、嗜热链球菌三联活菌片”,商品名为金双歧。金双歧在临床上应用较为广泛,获得医护工作者及患者的一致好评。现将金双歧…     

Geographical and morphological variation within and between colour phases in Coris julis (L. 1758), a protogynous marine fish

The possible differences between sexes in patterns of morphological variation in geographical space have been explored only in gonochorist freshwater species. We explored patterns of body shape variation in geographical space in a marine sequential hermaphrodite species, Coris julis (L. 1758), analyzing variation both within and between colour phases, through the use of geometric morphometrics and spatially‐explicit statistical analyses. We also tested for the association of body shape with two environmental variables: temperature and chlorophyll a concentration, as obtained from time‐series of satellite‐derived data. Both colour phases showed a significant morphological variation in geographical space and patterns of variation divergent between phases. Although the morphological variation was qualitatively similar, individuals in the initial colour phase showed a more marked variation than individuals in the terminal phase. Body shape showed a weak but significant correlation with environmental variables, which was more pronounced in primary specimens. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 148–162.     

The prevalence and antimicrobial resistance phenotypes of Salmonella,Escherichia coli and Enterococcus sp. in surface water

Surface water is prone to bacterial contamination as it receives wastes and pollutants from human and animal sources, and contaminated water may expose local populations to health risks. This review provides a brief overview on the prevalence and antimicrobial resistance (AR) phenotypes of Salmonella, Escherichia coli and Enterococcus, found in natural freshwaters. These bacteria are frequently detected in surface waters, sometimes as etiological agents of waterborne infections, and AR strains are not uncommonly identified in both developed and developing countries. Data relating to Salmonella, E. coli and Enterococcus present in environmental water are lacking, and in order to understand their development and dissemination using the One Health approach, understanding the prevalence, distribution and characteristics of the bacteria present in surface water as well as their potential sources is important. Furthermore, AR bacteria in natural watersheds are not well investigated and their impacts on human health and food safety are not well understood. As surface water is a receptacle for AR bacteria from human and animal sources and a vehicle for their dissemination, this is a crucial data gap in understanding AR and minimizing its spread. For this review, Salmonella, E. coli and Enterococcus were chosen to evaluate the presence of primary pathogens and opportunistic pathogens as well as to monitor AR trends in the environmental water. Studies around the world have demonstrated the widespread distribution of pathogenic and AR bacteria in surface waters of both developing and developed countries, confirming the importance of environmental waters as a reservoir for these bacteria and the need for more attention on the environmental bacteria for emerging AR.     

Helicobacter pylori strains vary cell shape and flagellum number to maintain robust motility in viscous environments

The helical shape of the human stomach pathogen Helicobacter pylori has been suggested to provide mechanical advantage for penetrating the viscous stomach mucus layer. Using single‐cell tracking and quantitative morphology analysis, we document marked variation in cell body helical parameters and flagellum number among H. pylori strains leading to distinct and broad speed distributions in broth and viscous gastric mucin media. These distributions reflect both temporal variation in swimming speed and morphologic variation within the population. Isogenic mutants with straight‐rod morphology showed 7–21% reduction in speed and a lower fraction of motile bacteria. Mutational perturbation of flagellum number revealed a 19% increase in speed with 4 versus 3 median flagellum number. Resistive force theory modeling incorporating variation of both cell shape and flagellum number predicts qualitative speed differences of 10–30% among strains. However, quantitative comparisons suggest resistive force theory underestimates the influence of cell body shape on speed for helical shaped bacteria.     

Local factors control the community composition of cyanobacteria in lakes while heterotrophic bacteria follow a neutral model

1. Neutral community models are derived from the proposition that basic probabilities of species loss (extinction, emigration) and gain (immigration, speciation) explain biological community structure, such that species with many individuals are very likely to be widespread. Niche models on the other hand assume that interactions between species and differential resource use mediate species coexistence, thus invoking environmental factors to explain community patterns. 2. In this study, we compared neutral and niche models to test how much of the spatial variability of assemblages of heterotrophic bacteria and phytoplankton in 13 lakes they could explain. Analysis of phytoplankton was restricted to cyanobacteria, so that they could be studied with the same molecular fingerprinting method, automated ribosomal intergenic spaces analysis (ARISA), as heterotrophic bacteria. We determined local biotic and abiotic lake variables as well as lake age, glacial history and distance between sites. 3. The neutral community model had a good fit to the community composition of heterotrophic bacteria (R² = 0.69), whereas it could not produce a significant model for the community composition of cyanobacteria. 4. The community composition of cyanobacteria was instead correlated to environmental variables. The best model, a combination of total organic carbon, biomass of eukaryotic phytoplankton, pH and conductivity, could explain 8% of the variation. In contrast, variation in the community composition of heterotrophic bacteria was not predicted by any of the environmental variables. Historical and spatial variables were not correlated to the community composition of either group. 5. The pattern found for heterotrophic bacteria suggests that stochastic processes are important. The correlation of cyanobacteria with local environmental variables alone is consistent with the niche model. We suggest that cyanobacteria, a group of organisms containing bloom‐forming species, may be less likely to fit a neutral community model, since these blooms are usually triggered by a particular combination of environmental conditions.     

麦积山石窟赋存环境中空气细菌的时空分布特征

【目的】空气微生物沉降及污染与文化遗产的微生物退化密切相关,本文对世界文化遗产地麦积山石窟赋存环境空气中细菌浓度和群落结构的季节性变化特征进行了系统研究,为石窟环境监测预警和文物预防性保护提供依据。【方法】利用生物气溶胶采样器,在2016年春、夏、秋和冬季分别采集空气样品;基于传统培养方法获得空气中细菌浓度及纯培养菌株;通过提取基因组DNA、扩增细菌16S rRNA、测序和系统发生树等分子技术研究细菌群落时空动态变化规律;结合环境监测数据,分析影响遗产地空气细菌变化的主要因素。【结果】监测期内,空气细菌浓度在(281.20–1409.20)CFU/m3之间,最高浓度出现在MJ4处的夏季,最低浓度出现在MJO处的春季;具有明显季节性变化特征,在空间层位分布上有所差异,但不显著(P0.05)。培养的细菌菌株经鉴定属于4个门11个属;芽孢杆菌属(Bacillus)、Paenarthrobacter、节杆菌属(Arthrobacter)、薄层菌属(Hymenobacter)和考克氏菌属(Kocuria)等为优势属。【结论】麦积山石窟空气细菌群落结构具有明显的季节性和空间分布动态变化特征;在石窟不同层位,空气中细菌群落分布与相对湿度、温度与降雨量相关;部分细菌种属如芽孢杆菌属、微球菌属(Micrococcus),为壁画及彩塑生物腐蚀的潜在病害菌;麦积山石窟及周边环境空气细菌的监测可为石窟保护和旅游开放管理提供重要参考。     

The adult body size variation of Dryas iulia (Lepidoptera,Nymphalidae, Heliconiinae) in different populations is more influenced by temperature variation than by host‐plant availability during the seasons

The body size of insects is affected by environmental conditions during development and can present considerable intraspecific variations, which can be seen as an ultimate consequence/adaptation to environmental conditions. This paper evaluated whether the body size of the butterfly Dryas iulia from subtropical populations was influenced by changing climate conditions and food source availability during the seasons. The likely reasons behind body size variation were also investigated. First, field data on body size variation, host‐plant availability and climate fluctuation throughout the seasons were recorded. Then, the effects of host‐plant species and temperature on body size were analyzed by controlled experiments. Field data revealed that body size and host‐plant availability varied significantly through the seasons. Populations had the smallest body size during the spring and the biggest size during summer, whereas host‐plant availability was lower during winter and higher during spring. The controlled experiments revealed that both temperature and host‐plant had significant effect on the plasticity of body size. Larvae subjected to winter temperature treatment led to smaller butterflies when compared to immatures reared under summer temperature treatment, and larvae fed with Passiflora misera produced bigger adults when compared to larvae reared on Passiflora suberosa. The combination of data gathered in the field and in the laboratory suggests that seasonal body size variation in D. iulia is related mainly to differences in the temperatures to which larvae are subjected during development, while host‐plant shifts caused by differential availability of food through the seasons had slightly effects on the variation observed.     

氧化胁迫诱导苍白杆菌JP1形成VBNC状态及其特征

石油降解菌在各种有害环境因素作用下会进入活的非可培养(viable but non-culturable, VBNC)状态，从而影响其生长及石油降解率。为了研究有害环境因素对石油降解菌生长及石油降解率的影响，采用分光光度法、荧光染色-激光共聚焦显微镜观测H₂O₂胁迫下苍白杆菌(Ochrobactrum sp.)JP1细胞的生长及VBNC状态形成情况。结果表明，不同浓度H₂O₂对其生长有一定抑制作用，当培养液中H₂O₂浓度为75.0 mmol/L时，可有效抑制苍白杆菌JP1生长，处理12 h后苍白杆菌JP1进入VBNC状态。VBNC状态的苍白杆菌JP1细胞缩小变成球体，周质间隙增大；在适宜条件下，VBNC状态苍白杆菌JP1能够复苏为可培养状态，添加丙酮酸钠能够促进VBNC状态细菌细胞的复苏。复苏后的苍白杆菌RJP1具有良好的环境适应性和石油降解能力，为石油污染生物修复的菌种筛选及应用提供了新的策略。     

Natural selection on the genetical component of variance in body condition in a wild bird population

Although there is substantial evidence that skeletal measures of body size are heritable in wild animal populations, it is frequently assumed that the nonskeletal component of body weight (or ‘condition’) is determined primarily by environmental factors, in particular nutritional state. We tested this assumption by quantifying the genetic and environmental components of variance in fledgling body condition index (=relative body weight) in a natural population of collared flycatchers (Ficedula albicollis), and compared the strength of natural selection on individual breeding values with that on phenotypic values. A mixed model analysis of the components of variance, based on an ‘animal model’ and using 18 years of data on 17 717 nestlings, revealed a significant additive genetic component of variance in body condition, which corresponded to a narrow sense heritability (h²) of 0.30 (SE=0.03). Nongenetic contributions to variation in body condition were large, but there was no evidence of dominance variance nor of contributions from early maternal or common environment effects (pre‐manipulation environment) in condition at fledging. Comparison of pre‐ and post‐selection samples revealed virtually identical h² of body condition index, despite the fact that there was a significant decrease (35%) in the levels of additive genetic variance from fledging to breeding. The similar h² in the two samples occurred because the environmental component of variance was also reduced by selection, suggesting that natural selection was acting on both genotypic and environmental variation. The effects of selection on genetic variance were confirmed by calculation of the selection differentials for both phenotypic values and best linear unbiased predictor (BLUP) estimates of breeding values: there was positive directional selection on condition index both at the phenotypic and the genotypic level. The significant h² of body condition index is consistent with data from human and rodent populations showing significant additive genetic variance in relative body mass and adiposity, but contrasts with the common assumption in ecology that body condition reflects an individual’s nongenetic nutritional state. Furthermore, the substantial reduction in the additive genetic component of variance in body condition index suggests that selection on environmental deviations cannot alone explain the maintenance of additive genetic variation in heritable traits, but that other mechanisms are needed to explain the moderate to high heritabilities of traits under consistent and strong directional selection.     

Geographic morphological variation in parapatric Western Palearctic tree frogs,Hyla arborea and Hyla savignyi: are related species similarly affected by climatic conditions?

Tree frogs Hyla arborea and Hyla savignyi are similar, closely‐related species distributed in Europe and the Middle East. We investigated geographic variation in body shape within and between these species, and tested its relationships to macroclimatic conditions. We used morphometric distances (based on size corrected external measurements) to construct phenetic trees (unweighted pair‐group method of arithmetical averages, Neighbour‐joining), and to test correlations between morphology, geography, and climate by the partial Mantel test. Regardless of their specific affiliation, the parapatric populations of both species from the eastern Mediterranean, where they occupy comparable habitats, are closer to each other in morphospace than to conspecific populations from distal regions. This local interspecific similarity is probably driven by the common response to environment, expressed here as macroclimatic conditions. In support, the geographically close but ecologically vicariant populations of both species from the Caucasus region differ quite substantially in body shape. We suggest that climate‐provoked phenotypic variation in closely‐related parapatric species should be taken into account as a potential complication to character displacement in morphology. Contrariwise, morphological diversification between related species or their populations could be enhanced by habitat shifts resulting in occupation of different environmental space. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 539–556.     

深圳近海表层浮游细菌分布特征及其环境影响因素

于2015年3月、5月、8月和10月在深圳市近岸海域(珠江口、深圳湾和大亚湾)采集表层水样,利用流式细胞仪测定总浮游细菌、高DNA含量亚群细菌(HNA)、低DNA含量亚群细菌(LNA)的丰度,分析它们的时空分布特点,阐释环境因子对浮游细菌时空分布格局的影响。结果表明,珠江口、深圳湾和大亚湾海域表层浮游细菌的平均丰度依次降低,分别为3.82×10~6个/mL、7.67×10~6个/mL和3.38×10~6个/mL。珠江口海域浮游细菌丰度由远岸到近岸递增,深圳湾海域湾内各站位浮游细菌丰度差异较小,大亚湾海域浮游细菌丰度空间差异不显著(P0.05)。浮游细菌丰度时间差异主要受温度影响,空间差异主要受营养盐和叶绿素a影响。HNA亚群丰度时空差异性比LNA亚群的大,HNA亚群受温度影响显著(P0.01),而LNA亚群与温度相关性不显著(P0.05)。环境对HNA和LNA亚群丰度的影响有许多相似之处,但两者对某些环境因子有着不同的响应,说明它们在近海表层生态系统中可能扮演着部分重叠但略有不同的角色。