单室微生物电解池除镍途径分析及微生物群落动态特征北大核心CSCD

【目的】为探究UASB颗粒污泥启动的单室微生物电解池(Single-chamber microbial electrolysis cell,SMEC)对Ni(II)的去除途径和SMEC中微生物群落的动态特征。【方法】以乙酸钠为底物,采用单因子控制方法分析SMEC对Ni(II)的去除途径和应用Illumina高通量测序技术解析SMEC启动过程中微生物群落的组成和结构动态学特征。【结果】结果表明,SMEC对重金属的去除主要通过吸附和微生物作用。经培养驯化功能菌群发生变化。成熟单室微生物燃料电池(Single-chamber microbial fuel cell,SMFC)阳极生物膜菌群主要是Proteobacteria(变形菌门,91.42%)中的Geobacter sp.(地杆菌属,76.25%);阴极生物膜菌群主要是Bacteroidetes(拟杆菌门,47.99%)中的Niabella sp.(布鲁氏菌属,33.01%)和Proteobacteria(45.74%)中的Ochrobactrum sp.(苍白杆菌属,10.80%)。成熟SMFC改装成的SMEC在12.5 mg-Ni(II)/L下,阳极生物膜菌群由单一优势菌Geobacter sp.转变为Geobacter sp.(41.56%)和Proteobacteria中的Azospirillum sp.(固氮螺菌属,5.97%);阴极生物膜菌群由Niabella sp.和Ochrobactrum sp.转变为Firmicutes(厚壁菌门,25.21%)中的Acetoanaerobium sp.(19.28%)、Proteobacteria(51.42%)中的Dokdonella sp.(16.48%)和Azospirillum sp.(9.49%)。【结论】本研究表明,污泥微生物经SMFC和SMEC驯化过程及Ni(II)的淘汰和选择,在电极上形成了稳定、高效产电与除镍菌群,优势菌群为Proteobacteria。     

嗜麦芽寡养单胞菌胞外蛋白酶功能研究进展

嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia)是广泛分布于自然界的革兰氏阴性杆菌。作为一种新型、与高死亡率相关的条件致病菌,嗜麦芽寡养单胞菌能够导致人类或其他生物感染多种疾病。近年来,越来越多的研究结果显示来自于细菌的胞外蛋白酶是导致宿主发病的关键蛋白质。因此,探究嗜麦芽寡养单胞菌胞外蛋白酶的组成成分和功能将不仅有助于阐明其致病机制,更为今后以其为靶点进行临床治疗奠定基础。本文试图对嗜麦芽寡养单胞菌胞外蛋白酶的性质、功能及其应用进行归纳总结。     

Mono-sulfonated tetrazolium salt based NAD(P)H detection reagents suitable for dehydrogenase and real-time cell viability assays

Glutamate dehydrogenase (GDH) catalyzes the oxidative deamination of L-glutamate and is important for several biological processes. For GDH inhibitor screening, we developed a novel mono-sulfonated tetrazolium salt (EZMTT), which can be synthesized using H₂O₂ oxidation and purified easily on silica gel in large quantities. The EZMTT detection method showed linear dose responses to NAD(P)H, dehydrogenase concentration and cell numbers. In E. coli GDH assay, the EZMTT method showed excellent assay reproducibility with a Z factor of 0.9 and caused no false positives in the presence of antioxidants (such as BME). Using the EZMTT-formazan-NAD(P)H system, we showed that EGCG is a potent E. coli GDH inhibitor (IC₅₀ 45 nM) and identified that Ebselen, a multifunctional thioredoxin reductase inhibitor, inactivated E. coli GDH (IC₅₀ 213 nM). In cell-based assays at 0.5 mM tetrazolium concentration, EZMTT showed essentially no toxicity after a 3-day incubation, whereas 40% of inhibition was observed for WST-8. In conclusion, EZMTT is a novel tetrazolium salt which provides improved features that are suitable for dehydrogenases and real-time cell-based high-throughput screening (HTS).