肠道微生物对土壤中铜、锌、锰生物可给性的影响

为了更全面、准确地评价土壤中金属元素对人体的健康风险,研究土壤中金属元素在结肠阶段的生物可给性具有重要意义。通过采集我国一些地区的6种土壤,利用in vitro方法(PBET和SHIME联用)研究土壤中Cu、Zn、Mn在胃、小肠、结肠阶段的生物可给性。研究显示,土壤中Cu、Zn、Mn在胃阶段的生物可给性分别为23.8%~63.0%、21.2%~64.4%、11.7%~35.6%;从胃阶段到小肠阶段,土壤中Cu的生物可给性提高了0.4%~14.4%,而土壤中Zn在小肠阶段的生物可给性降低了6.7%~38.7%。结肠阶段,土壤中Cu、Zn、Mn的生物可给性分别为2.4%~12.9%、5.7%~18.7%、6.2%~18.9%,与小肠阶段相比,分别降低了21.7%~56.9%、0.4%~36.8%、4.5%~19.1%。结果表明,在肠道微生物存在的情况下,土壤中Cu、Zn、Mn在结肠阶段有较低的人体健康风险。     

张掖地区造纸厂废水灌溉区域微型生物调查研究

通过对造纸废水流经灌区不同点进行微型生物监测 ,从微型生物的指示性角度出发 ,来说明造纸废水水质污染状况。通过监测得知 ,废水灌区微型生物共有 3 8种。其中藻类 1 0种 ,原生动物 2 8种。 3 8种微型生物均属多污性、α-中污性或 β-中污性种类 ,说明造纸废水治理效果较差且对灌区农作物及生态污染较严重。如何解决废水污染及灌区对废水的依赖性 ,应引起有关部门的重视。     

Respiration induced by substrate and bacteria diversity after application of diuron,hexazinone, and sulfometuron-methyl alone and in mixture

Abstract

After application, herbicides often reach the soil and affect non-target soil microorganisms, decreasing their population, diversity or affecting metabolic activity. Therefore, laboratory studies were performed to evaluate the effects of diuron, hexazinone and sulfometuron-methyl alone and mixed upon carbon transformation by soil microorganisms in clayey and sandy soils and the effect on bacterial diversity and structure. Control treatment without herbicide application was also performed. Sub-samples from the control and herbicide treatments (10?g – in triplicate) were collected before herbicide application and 7, 14, 28 and 42?days after treatment (DAT), then 1?mL of ¹⁴C-glucose solution was applied. The released ¹⁴CO₂ was trapped in 2?M NaOH solution and the radioactivity was analyzed by liquid scintillation counting (LSC), 12?h after glucose application. The effect of herbicides on bacterial diversity was evaluated by T-RFLP. The experiment was conducted in a complete randomized design. Hexazinone did not affect ¹⁴CO₂ evolution. Diuron showed a greater ¹⁴CO₂ evolution in sandy and clayey soil, while sulfometuron-methyl led to an increase in sandy soil, at 42 DAT. A greater evolution of carbon was observed in the treatment with herbicide mixture in sandy soil, compared with the same treatment in clayey soil or control. However, the herbicide mixture application did not affect the soil biological activity measured by the respiration rate induced by substrate. On the other hand, the herbicide mixtures affected the bacterial diversity in both soils, being the strongest effect to diuron and sulfometuron-methyl in clayey soil and hexazinone in sandy soil.     

蚯蚓摄食污泥对其肠道功能区微生物种群及耐药基因的影响

以赤子爱胜蚓(Eisenia fetida)为实验蚓种, 研究蚯蚓消化污泥前后, 其肠道各功能区微生物种群结构及耐药基因(ARGs)丰度的变化情况.为表征活体功能性微生物, 所取新鲜样品均采用叠氮溴化丙锭(PMA)预处理后, 再进行DNA相关分析.结果表明: 蚯蚓消化污泥5d后, 细菌16S rDNA和真核生物18S rDNA的丰度在其胃中分别显著增加了28.2倍和42.2倍(P<0.05), 而在砂囊和后肠中均显著性降低(P<0.05).此外, 蚯蚓消化污泥使其砂囊中的优势菌门由变形菌门变为软壁菌门, 胃中的优势菌门由拟杆菌门变为厚壁菌门, 而对后肠微生物种群结构的影响较小.对于ARGs而言, 大环内酯类耐药基因ermF、四环素类耐药基因tetX和磺胺类耐药基因sul2在蚯蚓胃中的丰度分别显著升高了1.9×10²倍、8.4×10⁵倍和25.9倍(P<0.05), 而在其砂囊和后肠中ARGs总丰度分别显著下降了11.0倍和45.2倍(P<0.05).基于网络分析结果显示, 蚯蚓摄食污泥可影响其肠道内ARGs宿主细菌的结构多样性.     

大麦虫幼虫肠道菌群对聚苯乙烯泡沫塑料降解

聚苯乙烯（polystyrene,PS）是广泛使用且难以降解的主要塑料材料之一.在本研究中,选择大麦虫幼虫（Zophobas morio）对PS进行生物降解,发现大麦虫幼虫在为期50 d的培养时间仅摄取PS,能够保持较高存活率（73%）.使用傅里叶变换红外光谱分析大麦虫的虫粪,证实了虫粪中的PS形成了新的含氧官能团.凝胶渗透色谱分析表明,大麦虫摄入PS后其虫粪的重均分子量（M_w）和数均分子量（M_n）均向减小的方向偏移,表明大麦虫摄入的PS发生了降解.使用16S rRNA基因测序技术,分析PS、麦麸和麦麸加PS这3种不同的饲喂条件下大麦虫的肠道细菌,结果表明在不同的摄食条件下,Z.morio的肠道菌群表现出显著差异.在PS饲喂条件下,大麦虫肠道中具有降解PS功能的优势菌群,例如克雷伯氏菌（Klebsiella）和柠檬酸杆菌属（Citrobacter）等显著富集.以PS为唯一碳源,对大麦虫肠道微生物进行为期90 d的体外培养实验,结果发现具有PS降解功能的肠道菌群显著富集.本研究证明了肠道细菌在大麦虫幼虫降解PS的过程中发挥了重要作用,为PS的生物降解提供了新的理论依据与应用思路.     

肠道微生物与环境健康关系的研究进展与展望

尽管肠道微生物群落在调节宿主多种生理功能的稳态以及抵抗环境污染物的毒性等方面至关重要,但是其在环境健康上的作用直到近几年才引起关注.本综述主要概述了环境污染物对肠道微生物的作用导致的健康效应的最新研究进展.发展迅速的高通量测序平台与合成生态学方法有助于快速确定肠道微生物组成,结合信息化综合分析方法可进一步探明肠道微生物...     

应用SHIME模型研究肠道微生物对土壤中镉、铬、镍生物可给性的影响

为了研究人体肠道微生物对土壤中Cd、Cr、Ni生物可给性的影响.本文采集我国一些地区的5种土壤,利用in vitro方法(PBET和SHIME联用)研究了这些土壤中Cd、Cr、Ni在胃、小肠、结肠阶段的生物可给性及其对人体的健康风险.结果表明,土壤中Cd、Cr、Ni在胃阶段的生物可给性分别为4.3%~94.0%、6.4%~21.6%、11.3%~47.3%;小肠阶段,土壤中Cr和Ni的生物可给性与胃阶段一致或有一定升高,但Cd的生物可给性降低了1.4~1.6倍(土壤2除外);胃肠阶段,Cd的平均生物可给性较高,而Cr的较低.结肠阶段,土壤中Cr和Ni的生物可给性均升高,是小肠阶段的1.3~2.4倍和1.0~2.1倍,分别达到了17.6%~38.7%和25.4%~56.0%;而Cd的生物可给性也升高(土壤3和4除外);Ni的平均生物可给性最高.由此可见,肠道微生物可以促进土壤中Cd、Cr、Ni的溶出释放,提高了三者的生物可给性,可能增大了人体的健康风险.     

High starter phosphorus fertilization facilitates soil phosphorus turnover by romoting microbial functional interaction in an arable soil

Microbial phosphorus (P) turnover is critical in C utilization efficiency in agroecosystems. It is therefore necessary to understand the P mobilization processes occurring during P fertilization in order to ensure both crop yield and environmental quality. Here, we established a controlled pot experiment containing soil amended with three different levels of starter P fertilizer and collected soil samples after 30, 60, and 90 days of incubation. Quantitative microbial element cycling (QMEC) smart chip technology and 16S rRNA gene sequencing were used to investigate functional gene structures involved in carbon, nitrogen and P cycling and the bacterial community composition of the collected samples. Although P fertilization did not significantly affect the structure of the soil microbial community, some rare microbiota were changed in particular phosphorus-solubilizing bacteria were enriched at the high P fertilization level, suggesting that the rare taxa make an important contribution to P turnover. P fertilization also altered the functional gene structure, and high P concentrations enhanced the functional gene diversity and abundance. Partial redundancy analysis further revealed that changes in rare taxa and functional genes of soil microorganisms drive the alteration of soil P pools. These findings extend our understanding of the microbial mechanisms of P turnover.     

膜-生物反应器中微型动物变化与活性污泥状态相关性研究

近年来出现的膜-生物反应器(MBR)技术,是一种污水处理和回用的新型工艺。由于该工艺污泥停留时间长、污泥浓度高等特点,与常规活性污泥工艺差距较大,所以对反应器内的生物相监测是研究其处理机理的重要内容。笔者采用处理生活污水的MBR工艺连续流小试运行方式,结合生物学分析方法,对系统活性污泥混合液中的微型动物进行了连续跟踪监测。结果发现,微型动物优势种群及其数量随环境变化而波动,呈现一定的规律性。按照运行时间的顺序,游动型纤毛虫、红斑瓢体虫、轮虫及累枝钟虫、表壳虫,交替成为优势种群。系统内发生丝状菌污泥膨胀后,微型动物种类减少,主要优势种群为轮虫、累枝钟虫、表壳虫。微型动物在活性污泥中发挥吞食作用以控制系统内活性污泥总量的增长,而活性污泥的状态特性又会反作用于微型动物的生活过程及数量的变化过程。MBR系统中,微型动物与活性污泥整体之间是一种相互影响、相互作用的动态变化过程。      

人体肠道耐药基因组的研究进展

人类肠道菌群是耐药基因(antibiotic resistance genes,ARGs)的"储存库",且与人体健康密切相关。目前,抗生素的滥用严重,进一步加剧了耐药基因的传播和扩散。细菌耐药问题严重影响人体健康、食品安全和生态安全,携带耐药基因的致病菌对临床治疗造成巨大威胁。本文结合国内外研究进展,在总结人体肠道耐药基因组研究方法的基础上,探讨了肠道耐药基因的组成、来源、传播和进化,并对未来研究进行了展望,旨在促进公众对肠道耐药基因的认知,并为抗生素的合理使用提供理论支持。