口腔菌群与肠道健康

人类口腔栖息着细菌、古生菌和病毒等多种微生物,口腔菌群是人体微生物组的重要组成部分。口腔中的条件致病菌,尤其是牙龈卟啉单胞菌和具核梭杆菌等,不仅充当着牙周病原体的传统角色,还可以通过各种方式进入肠道。越来越多的研究表明,口腔菌群与肠道菌群主要以协同或合作的方式致病,这些微生物群与人体的生理状态密切相关。本文就口腔菌群与肠道菌群的相互作用及其在炎症性疾病和结肠癌等肠道疾病发病中的作用进行综述。     

健康青少年口腔正常菌群的初步研究

本文采用非选择性培养基对22名健康青少年的唾液、沟裂菌斑、龈上菌斑及龈下菌斑中的需氧菌、兼性厌氧菌及专性厌氧菌进行了分离培养,并计算其在不同标本中占可培养菌的百分比及检出率。结果共分离到包括18个菌属的35种细菌。其中,链球菌、放线菌、奈瑟氏球菌、二氧化碳噬纤维菌、类杆菌、梭杆菌,奴卡氏菌及棒状杆菌在口腔4个部位的检出率及所占比例均较高,是健康青少年口腔中的优势菌群.通过比较还发现,其中一些菌在口腔4个部位的分布存在一定差异.本文还采用刚果红负性染色涂片法,镜下观察龈上、龈下菌斑中的螺旋体,并计算其相对比例.结果龈下菌斑中螺旋体的相对比例明显高于龈上菌斑.     

胃癌患者化疗前后口腔菌群与肠道菌群变化特征

目的 研究胃癌患者化疗前后口腔菌群与肠道菌群的变化特征,为该类患者的治疗提供参考.方法 选取2017年2月至2020年2月于我院接受治疗的96例胃癌患者为观察组,另外选取同期我院健康体检者90例为对照组,收集两组对象唾液样本和粪便样本,其中观察组患者需收集化疗前及化疗后两个时间点的样本.采用16SrRNA基因高通量测序...     

腹泻儿童肠道菌群结构特征的ERIC-PCR指纹图分析

目的 :了解以粪检有无白细胞区分的两类腹泻儿童肠道菌群结构的特征及其与健康儿童的差别。方法 :提取健康儿童 (H)、临床门诊粪检无白细胞的腹泻儿童 (L )和粪检有白细胞的腹泻儿童 (L +)(各 11例 )粪便总DNA作模板 ,获得反映肠道菌群组成特征的ERIC PCR指纹图谱。结果 :以H、L 和L +为序 ,每类样品以独特的ERIC条带为代表的操作分类单元 (OTU)的总数分别为 5 4∶4 7∶2 6 ;每类样品ER IC图谱多样性指数范围分别为 :2 4 5± 0 14 ,2 11± 0 18和 1 76± 0 19。组内成对相似性系数累积曲线分析 :小于 0 6的CS 值在L 组占到总Cs值个数的 70 % ,在H组占 5 0 % ,而在L +组只占 30 %。结论 :腹泻儿童肠道的菌群结构多样性降低 ,粪检有白细胞腹泻个体较之粪检无白细胞腹泻个体肠道菌群结构偏离健康个体更远。     

影响人肠道微生物菌群结构的因素

肠道微生物与人类健康状况直接相关。目前,微生物研究者已对影响人及模式动物(主要为鼠和猪)肠道微生物菌群结构的因素展开了广泛研究,取得了较大研究进展。本文综述了影响肠道微生物菌群结构的因素,主要有年龄、宿主基因型、宿主所处环境、食物和抗生素等,以使人们了解和控制这些因素,从而保持良好的健康状态。     

口腔及肠道菌群与冠心病关系的研究进展

冠心病是由多种病理因素引起的复杂疾病,严重威胁人类健康,其机制尚未完全阐明。近年来,研究表明冠心病与口腔和肠道菌群密切相关。菌群失调导致的炎症反应、氧化应激反应、脂质代谢失调和氧化三甲胺累积是参与冠心病发生的主要风险因素。此外,口腔菌群与肠道菌群相关,参与冠心病的发生与发展。中医治疗疾病的优势在于辨证论治,而证型的判断缺乏客观标准。多项研究应用口腔菌群或肠道菌群分析了疾病的中医证型。本文系统地阐述了口腔菌群和肠道菌群在冠心病发病机制中的作用,阐述了不同中医证型冠心病菌群分析的研究进展,为临床开展此类研究提供参考。     

低龄儿童龋病牙菌斑的菌群结构分析

目的通过低龄龋齿儿童与口腔健康儿童的微生物组检测,探讨低龄儿童龋病牙菌斑的菌群组成特征。方法在深圳地区招募轻度龋齿、重度龋齿及口腔健康儿童共100名,采集其牙菌斑或健康牙齿表面微生物样本,采用MiSeq测序平台进行16S V4-V5区域的高通量测序。同时,通过生物信息分析方法,对低龄龋齿儿童的牙菌斑的微生物组成的特征进行挖掘分析。结果相对口腔健康儿童,重度龋齿患儿的牙菌斑微生物多样性增加,轻度龋齿患儿则减少,但变化不显著。门水平的优势菌主要为放线菌门、变形菌门及拟杆菌门,虽有相对丰度变化但差异无统计学意义。前10位的优势菌属中,轻度及重度龋齿儿童的最高丰度优势菌属为棒状杆菌属,重度龋齿儿童与健康儿童中的棒状杆菌丰度差异有统计学意义(t=-2.195 5, P=0.028 1)。健康儿童口腔的优势菌属包含了卟啉单胞菌属,但在轻度及重度龋齿儿童的优势菌属则替换为月形单胞菌属。种水平的菌群结构分析显示,前10位的优势菌丰度变化差异无统计学意义,而低丰度的致病菌如变异链球菌(H=27.302 1, P<0.000 1)、Atopobium parvulum(H=17.418 2, P=0.000 2)、栖牙普氏菌(H=10.598 9, P=0.005 0)、唾液普氏菌(H=10.035 0, P=0.006 6)等则在重度龋齿儿童中显著富集。结论低龄龋齿儿童的牙菌斑微生物结构发生了改变,部分口腔有害菌的丰度显著增加与龋病严重程度密切相关。     

儿童呼吸道菌群的调查

目的了解儿童呼吸道菌群的分布特征。方法对重庆医科大学附属儿童医院的呼吸内科住院部500例小儿下呼吸道负压吸引法痰标本做分离培养;105例门诊未使用抗生素有咽部体征的上呼吸道患儿咽拭子标本做分离培养;同时对150例健康儿童上呼吸道咽拭子标本做分离培养,对他们的生长菌群进行分类鉴定和药敏试验,并对结果作对比分析讨论。结果草绿色链球菌、表皮葡萄球菌、金黄色葡萄球菌、溶血葡萄球菌、流感嗜血杆菌检出率差异无显著性（P〉0.05）;而儿童下呼吸道痰标本结果和105例门诊上呼吸道患儿咽拭子标本结果比较大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌、肺炎链球菌、副流感嗜血杆菌、卡他莫拉菌、真菌差异无显著性（P〉0.05）,与150例健康儿童上呼吸道咽拭子标本结果比较差异有显著性（P〈0.05）。革兰阴性杆菌对亚胺硫霉素（IMP）耐药率最低,对哌拉西林/他唑巴坦（TZP）、阿米卡星（AK）、环丙沙星（CIP）耐药率〈30%;革兰阳性球菌未发现耐万古霉素（VA）菌株,对利福平（RD）、哌拉西林/他唑巴坦（TZP）耐药率相对较低;流感嗜血杆菌、副流感嗜血杆菌、卡他莫拉菌对CIP、IMP耐药率〈10%;肺炎链球菌无VA耐药菌株,对氧氟沙星（OFX）、RD耐药率〈10%;草绿色链球菌也无耐VA菌株;对RD、复方磺胺（SXT）、四环素（TE）耐药率〈30%。结论儿童正常菌群的分布特征以草绿色链球菌为主。从病原菌来看,下呼吸道住院患儿痰标本分离的致病菌大于门诊上呼吸道感染患儿咽拭子分离的致病菌大于健康儿童咽拭子标本携带的致病菌。     

慢性阻塞性肺疾病合并糖尿病患者口腔菌群及肠道菌群的研究

探讨慢性阻塞性肺疾病(COPD)合并糖尿病患者与糖尿病患者口腔菌群及肠道菌群的差异。

选取2019年5月到2020年5月于我院就诊的COPD合并糖尿病患者与仅患糖尿病的患者各30例。检测两组患者的各项身体指标以及生化指标。采集两组患者牙体颊/舌面液体, 提取细菌基因组DNA, 采用荧光定量PCR鉴定常见口腔细菌。采用贴纸收集粪便样本, 并用选择性琼脂培养基培养菌群, 结果以每毫升粪便的菌落形成单位(CFU)表示。通过BBL Crystal^TM鉴定系统对分离出的细菌进行鉴定。采用Elisa试剂盒测量粪便中Zonulin的水平(ng/mL)。

COPD合并糖尿病患者体质量指数[(29.54±2.16)kg/m²]较高, 血糖水平也较高, 但与糖尿病组比较差异无统计学意义(均P＞0.05)。COPD合并糖尿病患者CRP水平升高(P＜0.05), 其他各项指标两组间差异无统计学意义(均P＞0.05)。30例COPD合并糖尿病患者链球菌检出率为60.0%, 奈瑟菌检出率为30.0%, 放线菌检出率为66.7%, 韦荣球菌检出率为40.0%, 牙龈卟啉单胞菌的检出率为70.0%。30例糖尿病患者链球菌检出率为40.0%, 奈瑟菌检出率为56.7%, 放线菌检出率为36.7%, 韦荣球菌检出率为73.3%, 牙龈卟啉单胞菌的检出率为46.7%。Zonulin与炎症和真菌数量之间存在显著正相关。

COPD合并糖尿病患者肠道真菌数量、肠屏障功能与全身性炎症之间存在密切联系。

     

PCR指纹图谱技术分析人体口腔内微生物菌群结构

目的 应用PCR-DGGE指纹图谱技术对人体口腔微生物菌群结构进行系统性研究.方法 对1例健康人唾液周期性采集的样品和8例健康人个体的唾液与牙菌斑采集的样品,进行微生物群落总DNA的抽提.以此为模板扩增16S rRNA V3可变区,产物经DGGE指纹图谱分析其组成结构,并运用UVIBAND/MAP等软件比较所得群落指纹图谱的相似性指数.结果 同一健康人个体不同采样时间的唾液菌群结构相似性系数＞74%,通过对不同健康个体口腔样本的研究,发现同一个体的唾液与牙菌斑菌群结构存在差异（84%～95%）.结论 同一健康个体其唾液微生物菌群在一定时间内基本稳定,仅有微小的变化;唾液与同个体牙菌斑的微生物组成虽然存在差异,但这种差异要明显小于个体间的差异.     

An experimental model for the spatial structuring and selection of bacterial communities

Community-level selection is an important concept in evolutionary biology and has been predicted to arise in systems that are spatially structured. Here we develop an experimental model for spatially-structured bacterial communities based on coaggregating strains and test their relative fitness under a defined selection pressure. As selection we apply protozoan grazing in a defined, continuous culturing system. We demonstrate that a slow-growing bacterial strain Blastomonas natatoria 2.1, which forms coaggregates with Micrococcus luteus, can outcompete a fast-growing, closely related strain Blastomonas natatoria 2.8 under conditions of protozoan grazing. The competitive benefit provided by spatial structuring has implications for the evolution of natural bacterial communities in the environment.     

Direct and indirect effects of predators on the dominant invertebrates of two freshwater littoral communities

Summary Two congeneric damselfly species, Enallagma traviatum and E. aspersum, dominate the littoral macroinvertebrates of Bays Mountain Lake and of the adjacent fish-free Ecology Pond, respectively (northeastern Tennessee, USA). Extending previous experimental studies, we test seven hypotheses concerning the role of fish (bluegill sunfish, Lepomis macrochirus) and larvaldragonfly (Anax junius) predation, competitive effects on damselflies, and the interaction between competition and predation, in determining invertebrate dominance in these communities. Three types of experiments were conducted: an enclosure experiment within Ecology Pond, an outdoor replicated tub experiment, and a laboratory behavior experiment. The in-situ enclosure experiment showed that E. traviatum larvae were more susceptible to Anax predation than were E. aspersum larvae; a tendency toward greater vulnerability to fish of E. aspersum compared with E. traviatum was not statistically significant. The outdoor tub experiment confirmed both of these trends with statistically significant results. In the tubs, both predators inhibited feeding of both zygopterans (as indicated by reduced fecal mass), particularly for E. aspersum in the presence of fish. This effect appears to have been primarily indirect, mediated through exploitation of the zooplankton. We also detected competitive effects of E. traviatum on E. aspersum: E. traviatum reduced the emergence and increased the exposure above the substrate of E. aspersum. In the absence of predators, E. traviatum inhibited feeding of E. aspersum via interference. In the laboratory behavior experiment, predators inhibited crawling by E. aspersum. E. aspersum was more exposed than was E. traviatum; it swam and crawled more than did E. traviatum, considerably increasing these movements at night. Over all, E. traviatum consistently appeared to be the more cryptic of the two species, and E. aspersum appeared to be much more active. Our results suggest an explanation for the clear difference in structure between communities like Bays Mountain Lake and Ecology Pond: predaceous fish eliminate large invertebrate predators and shift the community toward cryptic forms at relatively low densities, reflecting the effects of both predation and exploitation competition. In the absence of fish, large invertebrate predators are less able to deplete littoral invertebrates but may favor the more active forms, perhaps because these are better able to avoid invertebrate predators.     

若尔盖高原泥炭沼泽湿地土壤细菌群落空间分布及其驱动机制

了解高原泥炭沼泽湿地生态系统土壤微生物群落结构组成、多样性及空间分布特征对认识高原湿地生态特征及演化过程至关重要。利用高通量测序技术,在局域尺度上研究了四川若尔盖高原泥炭沼泽湿地土壤细菌群落结构与多样性特征。通过进一步测定土壤及植物基本理化指标,量化采样点之间的地理距离,比较了细菌群落不同成员（稀有种和丰富种）的空间周转差异,分析了土壤环境变量和空间因子对细菌群落结构的相对贡献。结果表明：若尔盖泥炭土壤细菌群落主要由绿弯菌门（Chloroflexi）（26.25%）、变形菌门（Proteobacteria）（23.21%）、厚壁菌门（Firmicutes）（10.56%）等优势物种门类组成;土壤细菌群落结构表现出较强的空间依赖关系,群落结构相似性随采样点地理距离增加而逐渐降低,细菌群落的周转速率表现为总细菌群落 > 丰富种 > 稀有种;Mantel检验结果显示,地上生物量与细菌群落呈极显著相关性（P<0.01）,其中,影响稀有种空间分布特征的环境因子还包括土壤硫含量、活性磷、Mn和土壤pH值;方差分解分析表明,局域尺度上的土壤因子对若尔盖高原泥炭沼泽土壤细菌群落构建的相对贡献大于空间因子,土壤异质性是影响微生物空间分布特征的关键因素。研究为开展高原湿地泥炭土壤微生物多样性调查及揭示微生物群落构建机制提供了重要参考。     

The influence of coastal upwelling on the functional structure of rocky intertidal communities

Summary Relationships between organisms at all trophic levels are influenced by the primary productivity of the ecosystem, and factors which enhance rates of primary production may modify trophic relationships and community structure. Nutrient enrichment of intertidal and nearshore waters leads to enhanced production by intertidal algae, and it was hypothesized that where rocky shores are washed by nutrient-rich upwelled waters, the intertidal communities should show a characteristic functional structure, based on the effects of enhanced primary production. Study sites were chosen on rocky shores in southern Africa, central Chile and the Canary Islands, in areas with and without coastal upwelling, and mid-shore community structure at these sites was analysed in terms of the abundance of certain functional guilds of organisms.It was found that algal cover and the biomass of herbivorous limpets supported per unit area on rocky shores were significantly greater in regions of coastal upwelling than in regions where upwelling did not occur. Ground cover by sessile filter-feeding organisms was significantly greater on shores in non-upwelled areas. However, correspondence analysis showed no functional aspect of intertidal community structure that was characteristic of coasts washed by upwelled waters. Primary reasons for this are probably the large variations in the nature of nutrient enrichment that accompanies upwelling, and in the nutrient status of non-upwelled areas. Other factors are man's exploitation of intertidal organisms and differences in the genetic origins of the intertidal species involved.     

长山列岛南部三岛岩相潮间带群落多样性格局

对长山列岛南部南长山、北长山和大黑山岛屿岩相潮间带群落种类组成的调查表明,3岛屿岩礁潮间带的群落结构差异不大,表现在决定群落结构和外貌的前5位优势种群及其优势度序列基本相同;而砾石潮间带的群落结构存在一定差异,表现在北长山群落中优势种群及其优势度序列显著地区别于南长山和大黑山,但后二者趋同-3岛屿岩礁潮间带的景观和群落外貌与结构由东方小藤壶(Chthamalus chal-lengeri)、牡蛎（Ostrea spp.)、大型藻类和短滨螺(Littorina breuicula)控制,砾石潮间带则由东方小藤壶、大型藻类和平背蜞（Gaetice depressus)决定．群落多样性由物种丰富度(R)、均匀度(J)和多样性(HB、Hlv、DR、DIv)衡量,3岛屿岩礁潮间带群落的各种多样性指数呈现一致性,群落多样性以北长山最高,大黑山最低;而砾石潮间带群落的各种多样性指数存在一定差异,南长山高于北长山和大黑山,北长山潮间带群落中物种分布的均匀度最高,南长山和大黑山趋同．比较3岛屿两种基质潮间带的群落多样性发现,砾石潮间带高于岩礁潮间带。     

The oral health of older people from minority ethnic communities in south east England

Objectives: To describe the clinical health status and subjective oral health status of older adults from minority ethnic communities resident in South East England. Design: Cross sectional survey incorporating a clinical examination and a questionnaire assessment of subjective oral health status. Setting: Community groups working with individuals from minority ethnic communities. Subjects: A total of 540 individuals from 7 minority ethnic communities. Measures: Clinical assessment of oral health status using BASCD criteria. Assessment of oral symptoms and impact experienced together with satisfaction with oral status, by structured questionnaire. Results: On all measures of clinical health status the participants were healthier than a comparison group based on data from the Adult Dental Health Survey. The participants expressed high levels of subjective oral symptoms. Levels of satisfaction were lower than those found in the Adult Dental Health Survey. There was evidence of some variation across minority ethnic communities in clinical and subjective oral health status. Conclusions: Approximately 20% of the 540 adults from minority ethnic communities resident in the South East of England surveyed were relatively fit orally. They experienced a great many oral symptoms, and in approximately 30% of individuals these were sufficient to interfere with their quality of life. Ethical approval: The research described in this paper was approved by the Ethics committee of King's College London.     

Determining replication for discrimination among microbial communities in environmental samples using community-level physiological profiles

A statistical approach was employed to assess microbial community variability within a single 4-l water sample and among 10 independent 4-l water samples from a single location using community-level physiological profiles. Power calculations demonstrated that duplicate analyses could distinguish between two different locations at two times during the year. Variability associated with replicates from a single container or from different containers was nearly the same for the two sites examined. Duplicate assays (one from each of two independent samples) were sufficient to resolve the between-site differences at alpha=0.05 with power exceeding 0.95 at both times of the year. Similar methods are recommended to determine the appropriate number of replicates for environments of interest.     

Dynamics of plant communities in the Lomas of southern Peru

A study of the floristic composition of the plant communities of the Lomas was carried out in the Coastal Range of Arequipa, Peru. Data on the seasonal and elevational variation of those communities was obtained by monthly censusing a 20-meter circle sampling stations established at 100 m intervals from 300 to 1 000 m of elevation. The 80 recorded plants belong to 60 genera and to 20 families. Dominating life forms are Therophytes and Chamaephytes. Four vegetational zones (xeric, subxeric, mesic, and submesic), are separated by significant differences in the number of plants of each zone. Considering the entire Lomas transect, no significant statistical differences among the seasons were found. The floristic relationship among the altitudinal samples was found to be a reflection of a moisture pattern. The persistence in the Lomas of a mesophytic flora could be the result of a continuous adaptation to the fogginess and reduced solar radiation of this particular zone in a desert area.This study was supported by the Universidad Nacional de San Agustin, Arequipa, Perú, and by the Universidad de Los Andes through the Consejo de Desarrollo Cientifico y Humanistico (Proycet C-142-79). Amelia Díaz de Paseual, William E. Duellman, Evaristo López, Luis Malaret, Mario Ricardi and Antonio Vivas made helpful comments and criticisms. Field trips were shared with José Dávila, Evaristo López and Alberto Nuñez. The identification of plants was checked by Ramón Ferreyra and Oscar Tovar of the Museo Javier Prado, Lima, Perú, and Alwing Gentry of the Missouri Botanical Garden. I am grateful to all these institutions and people.