基于粒径分化的厌氧氨氧化污泥性能与微生物多样性分析

为明确基于粒径分化的厌氧氨氧化(ANAMMOX)污泥特性与菌群演替规律,研究了高氨氮生物滤池反应体系中ANAMMOX絮体污泥形成颗粒过程中的性能变化和微生物群落结构.结果 表明,粒径增加显著提高了厌氧氨氧化颗粒污泥(AnGS)比活性(SAA)和耐受性,R4(＞4.75 mm)的SAA最高为426.8 mg·(g·d)-...     

PVC微塑料对大型溞繁殖及应激与能量相关基因表达的影响

近年来,微塑料污染已成为海洋和淡水生态环境关注的热点问题.然而,目前有关微塑料对淡水生物影响的报道仍然较少.试验选择淡水模式动物大型溞作为受试生物,以2 μm聚氯乙烯微粒(PVC)作为研究对象,探讨了PVC微塑料对大型潘繁殖和基因表达的影响.急性毒性试验表明,PVC对大型潘的48 h LC50为20.5 mg·L-1....     

化肥和有机肥配施生物炭对土壤磷酸酶活性和微生物群落的影响

研究化肥和有机肥配施生物炭处理下植株根际、非根际土壤磷酸酶活性和phoC、phoD基因微生物群落多样性变化的规律,可为土壤磷库中难溶性磷素向植物根系可吸收的无机态磷酸根离子转化提供一定的理论指导,同时也为土壤中磷素有效性的提高和生物炭的农业利用提供一定的试验依据.本研究以玉米秸秆和稻壳秸秆为供试材料,采用盆栽试验的方法...     

First report of microcystin production in Microcystis smithii Komárek and Anagnostidis (Cyanobacteria) from a water bloom in Eastern China

A water bloom sample collected from Lake Dishui in Shanghai was characterized. The morphological identification showed that Micorcystis wesenbergii and Micorcystis smithii were the main component of the bloom. Five strains of M. smithii were successfully isolated. Their 16S rRNA gene sequences based phylogenetic tree showed that the five strains of M. smithii intermixed with strains of other morphospecies in Microcystis. A fragment of mcy gene encoding for microcystin synthetase was detected in one of the five M. smithii strains (CHAB 2183), indicating its potential of microcystin production. High performance liquid chromatography analysis confirmed M. smithii CHAB 2183 to produce microcystin-RR as 1550 g per gram dry weight cells. The present investigation, for the first time, reported the isolated strains of M. smithii and microcystin production from M. smithii.     

酵母双杂交技术构建重组雌激素受体相关受体(ERR)基因酵母

应用酵母双杂交技术构建了重组雌激素受体相关受体(ERR)基因酵母,用以筛选环境中具有ERR干扰活性的化合物.实验先提取并纯化含有ERR3,基因的酵母表达质粒pGBT9一ERRγ,称为诱饵质粒;再提取并纯化含有ERRγ协同激活因子GRIP1基因的酵母表达质粒,形成靶质粒pGAD424-GRIP1,然后将诱饵质粒和靶质粒同...     

基于mcrA基因的厌氧颗粒污泥产甲烷菌群分析

基于mcrA基因对阿维菌素废水处理工业化UASB厌氧颗粒污泥中产甲烷菌群进行分析,并与基于16S rRNA基因的产甲烷菌群分析结果进行比较.结果表明,基于2种目标基因PCR产物的DGGE图谱存在差异,但根据图谱计算所得产甲烷菌群Shannon多样性指数、Margalef丰富度指数和Berger-Parker优势度指数没有差异,表明基于2种目标基因的产甲烷菌群多样性分析基本一致.基于不同目标基因的优势产甲烷菌群系统发育种属的分析结果大体相似,产甲烷杆菌目和产甲烷八叠球菌目是厌氧颗粒污泥样品中的优势产甲烷种群;同时,分析结果的差异表明2种目标基因的检测特异性不完全相同.基于2种目标基因的产甲烷菌群FISH杂交区域具有很高的一致性,但杂交区域面积有所差异.基于mcrA基因FISH检测的产甲烷菌群平均相对丰度为24.25%±6.47%,低于基于16S rRNA基因FISH检测结果(33.42%±2.34%).以上结果表明,基于mcrA基因与基于16S rRNA基因的的产甲污泥菌群分析结果具有较高的相似度,mcrA基因可以作为16S rRNA基因的替代目标基因.     

苯系物联合暴露仿刺参管足转录组差异表达基因分析

为了分析苯系物(BTEXs)联合暴露后仿刺参(Apostichopus japonicus)管足转录组差异表达基因,采用Illumina Hi SeqTM2000测序技术,对1.0 mg·L~(-1)苯系物(B)联合暴露12 h后和对照组(C)的仿刺参管足组织分别进行转录组测序。经Trinity软件进行de novo组装,获得了145 675条unigenes。利用公共数据库进行同源比对,共注释了35 330条unigenes。对比分析苯系物联合暴露组和对照组的转录组测序结果,获得了2 418个差异表达基因(DEGs)(|Log2Fold changes|≥1且FDR≤0.001),其中,上调表达和下调表达基因分别为1 049和1 369个。GOseq分析结果显示,158个DEGs显著富集在149个GO terms中,包括103个生物学过程、17个细胞组分和29个分子功能(P0.05);KEGG代谢通路分析结果显示994个差异基因映射到268条代谢通路,这些差异表达基因参与的生理过程与其他生物的同源基因参与的信号传导、癌症、外源性化合物的生物降解代谢等过程相类似。上述结果为在转录组水平筛选苯系物的生物标志物,解析苯系物对仿刺参毒性作用的分子机制提供了科学参考。     

Role of Acinetobacter sp. in arsenite As(III) oxidation and reducing its mobility in soil

Microbial arsenite oxidation was observed by Acinetobacter sp. XS21, this strain oxidised arsenite As(III) up to 80?mM within 48–72?h of incubation. The present strain XS21 oxidised As(III) at a very high concentration in a shorter interval of time than any of the previous reported microbes. Further, XS21 was applied to the soil to observe its ability in reducing the mobility of As(III), and we found that Acinetobacter sp. XS21 efficiently removed arsenite from soluble-exchangeable fraction and removed 70% of the arsenite as compared to control. This feature makes it a potential candidate for bioremediation. Arsenic-resistant bacteria with strong As(III)-oxidising ability may have potential to improve bioremediation of As(III)-contaminated sites. To understand their basis of resistance and transformation we found the As(III) oxidase gene using degenerate primer and amplified ～550?bp of aioA gene. Amplified aioA gene sequence exhibiting 52% identity in terms of gene and deduced protein sequence to Uncultured bacterium, and Achromobacter sp. arsenite oxidase of larger subunit. Arsenite oxidase, an enzyme, was also observed in this isolate, which may provide a resistance and transforming ability. This bacterium was identified as Acinetobacter sp., by sequencing 16s rRNA gene sequence analysis.     

Effect of titanium dioxide nanoparticles on the expression of apoptotic markers in mouse blastocysts

Oocyte maturation, embryo development and expression of apoptotic-specific genes were evaluated in blastocysts of mice treated with titanium dioxide nanoparticles. Female mice received 0, 50 or 100?mg/kg/day titanium dioxide intraperitoneally for five consecutive days. After the last injection, pregnant mare serum gonadotropin and, 48?h later, human chorionic gonadotropin were administered intraperitoneally for induction of ovulation. After 14?h, mice were sacrificed and oocytes were collected. The number of mature oocytes was evaluated and then fertilization was carried out in vitro and the numbers of fertilized and cleaved oocytes and of blastocysts and the expression of Bax, caspase 3, and Bcl-xL genes in blastocysts were evaluated. The number of mature, fertilized and cleaved oocytes and of blastocyst embryos in the experimental groups were not different from control. The expression of Bax and caspase 3 genes was significantly elevated in the experimental groups compared to control, while expression of the Bcl-xL gene was significantly lower in the high dose group. Uptake of titanium dioxide nanoparticles at daily doses of 50?mg/kg and more may affect embryo development by alteration of pro-apoptotic and anti-apoptotic gene expression.     

Effects of selenium on activity of glutathione peroxidase and expression of selenium metabolism-related genes in Brassica

Inorganic selenium (Se) is absorbed and enriched by plants and converted into a stable and nutritionally important organic form, which subsequently when consumed by humans or animals results in increased Se tissue levels. Brassica is one of the most potent Se-enriched plants. The aim of this study was to compare differences in Se enrichment between two predominant Brassica plants namely Brassica rapa Linn L. and Brassica tumida Tsenet Lee L. on Se metabolic parameters. Plants exposed to soil Se levels (0, 0.5, 1, 2.5 or 5?mg/kg) were examined on the activity of glutathione peroxidase (GSH-Px), Se levels and expression of Se metabolism related genes using soil pots. Data showed that activities of GSH-Px in leaf and root of the two Brassica species were significantly increased in the presence of Se at 2.5?mg/kg. Se concentrations of leaf, stem and root in B. tumida Tsenet Lee L. and B. rapa Linn L. rose from 0.31 to 21.84-fold (leaf), 1.15 to 15.16-fold (stem) and 2.11 to 15.26-fold (root) in the presence of metal in a concentration-dependent manner. The highest expression levels of adenosine triphosphate (ATP), ATP sulfurylase (APS), selenocysteine methyltransferase (SMT), serine acetyltransferase (SAT), cysteine desulfurase (CysD) and S-adenosyl-l-Met:l-Met S-methyltransferase (MMT) in leaf of B. rapa Linn L. were found at 1?mg/kg Se. The highest expression levels of ATP, APS, SMT, SAT, CysD and MMT in leaf of B. tumida Tsenet Lee L. were observed at 2.5?mg/kg Se. The Se concentrations in leaf, stem and root of B. rapa Linn L. were higher than in B. tumida Tsenet Lee L. under the same soil Se level conditions. At the same Se level, differences in the expression of Se-related genes were observed between these two Brassica species. Our observations may be used to optimize the utilization of Brassica as a nutritional source of Se by growing this plant under certain soil conditions.