Aerobic denitrification by novel isolated strain using NO-₂-N as nitrogen source

Biological denitrification reaction can be achieved under aerobic environment. Few aerobic denitrifiers using nitrite as sole nitrogen source were identified. Using nitrite as the sole nitrogen source, this work assessed the denitrification activity of yy7, an aerobic heterotrophic denitrifier identified as Pseudomonas sp. (94% similarity) by 16S rRNA sequencing analysis. The logistic equation describes the cell growth curve, yielding a generation time of 2.9h at an initial 18 mg l(-1)NO(-)?-N. Reduction of NO(-)?-N was primarily achieved during its logarithmic growth phase, and was accompanied by an increase in suspension pH and near complete consumption of dissolved oxygen. Three genes relating to nirK, norB, and nosZ were noted to involve in isolate strain. Isolate yy7 can survive and remove up to 40 mg l(-1)NO(-)?-N and, hence, can be applied as an effective aerobic denitrifier during simultaneous nitrification and denitrification via nitrite processes.     

光学方法分析GABA及GABAA受体在脑干听觉传入通路的作用

目的旨在探讨脑干听觉传入通路中GABA能神经递质及GABAA受体对电刺激位听神经传入冲动的影响.方法使用出生后0～5 d的ddy/ddy小鼠制备脑干切片.脑片经电压敏感染料NK3041染色,电刺激与脑片相连的位听神经残端.使用16×16像素的硅光电二极管阵列测量光学信号.所采集的数据使用ARGUS50/PDA软件分析.结果多部位的光学记录方法显示了从位听神经到耳蜗核和前庭核的兴奋性传导的时间-空间分布.其中每一个光学成分由快峰电位样反应和慢反应组成.抑制性神经递质GABA可降低诱发的光学信号的快反应和慢反应,GABAA受体拮抗剂荷包牡丹碱可增强这些反应.结论16×16像素的硅光电二极管阵列可记录位听神经刺激诱发的多部位光学信号,每一个光学信号含有突触前及突触后电位成分.抑制性神经递质GABA和GJBAA受体拮抗剂可调节光学信号的兴奋性传导.     

The chemiluminescence immunoassay for aflatoxin B1 based on functionalized magnetic nanoparticles with two strategies of antigen probe immobilization

A rapid and sensitive chemiluminescence immunoassay (CLIA) based on magnetic nanoparticles (MNPs) was developed to detect aflatoxin B1 (AFB1), which is a potent carcinogen in nature. We prepared monodisperse MNPs (300 nm in diameter) according to the solvothermal synthesis reaction and the MNPs were coated with silica by the Stöber method. Triethox was used as a one‐step carboxylation reagent, and 3‐aminopropyltriethoxysilane (APTES) an amination reagent, to modify the MNPs. We prepared two types of solid phase antigens using the above synthesized functionalized MNPs coupled with the later prepared AFB1‐oxime active ester and the purchased BSA–AFB1 respectively. 2′,6′‐dimethylcarbonylphenyl‐10‐sulfopropylacridinium‐9‐carboxylate 4′‐N‐hydroxysuccinimide (4′‐NHS) ester (NSP–DMAE–NHS), as a novel luminescent reagent, was used to label anti‐AFB1 antibodies. The two CLIA calibration curves based on the two types of solid phase antigens were obtained and compared. The acquired limit of detection (LOD) was about 0.001 ng/mL for the two functionalized MNPs‐based immunoassays, and the half maximal inhibitory concentration (IC₅₀) was 0.51 ng/mL for the MNPs–AFB1‐based method and 0.72 ng/mL for the MNPs–BSA–AFB1‐based method.     

31例非特异性阴道炎病人阴道微生物群的研究

本文对31例非特异性阴道炎病人和31例正常人阴道微生物群进行定性、定量分析.结果表明,阴道炎病人的阴道乳杆菌的平均浓度明显低于正常人,而肠杆菌科、葡萄球菌、棒状杆菌、类杆菌属、支原体却明显增多,阴道炎病人未发现特异性病原体,菌群失调可能是其发病因素。乳杆菌为阴道正常优势菌,对改善阴道的微环境,防止条件致病菌引起的内源性感染具有重要的生理作用。     

Effects of size,neighbors, and site condition on tree growth in a subtropical evergreen and deciduous broad‐leaved mixed forest,China

Successful growth of a tree is the result of combined effects of biotic and abiotic factors. It is important to understand how biotic and abiotic factors affect changes in forest structure and dynamics under environmental fluctuations. In this study, we explored the effects of initial size [diameter at breast height (DBH)], neighborhood competition, and site condition on tree growth, based on a 3‐year monitoring of tree growth rate in a permanent plot (120 × 80 m) of montane Fagus engleriana–Cyclobalanopsis multiervis mixed forest on Mt. Shennongjia, China. We measured DBH increments every 6 months from October 2011 to October 2014 by field‐made dendrometers and calculated the mean annual growth rate over the 3 years for each individual tree. We also measured and calculated twelve soil properties and five topographic variables for 384 grids of 5 × 5 m. We defined two distance‐dependent neighborhood competition indices with and without considerations of phylogenetic relatedness between trees and tested for significant differences in growth rates among functional groups. On average, trees in this mixed montane forest grew 0.07 cm year^?1 in DBH. Deciduous, canopy, and early‐successional species grew faster than evergreen, small‐statured, and late‐successional species, respectively. Growth rates increased with initial DBH, but were not significantly related to neighborhood competition and site condition for overall trees. Phylogenetic relatedness between trees did not influence the neighborhood competition. Different factors were found to influence tree growth rates of different functional groups: Initial DBH was the dominant factor for all tree groups; neighborhood competition within 5 m radius decreased growth rates of evergreen trees; and site condition tended to be more related to growth rates of fast‐growing trees (deciduous, canopy, pioneer, and early‐successional species) than the slow‐growing trees (evergreen, understory, and late‐successional species).     

低频脉冲电场对PC12细胞酪氨酸羟化酶和多巴胺合成的影响

运用Western印迹和HPLC分别测定不同时间电场刺激和刺激后不同培养时间条件下,PC12细胞内酪氨酸羟化酶(TH)和细胞培养液中多巴胺(DA)含量的变化。结果显示,受到短时间(5、10min)脉冲电场刺激的PC12细胞,经较短时间(2天)的培养后,细胞内TH的含量和培养液中DA的含量均比对照组有所提高,但随着培养时间的延长(3~5天),TH和DA的含量均明显下降。然而,长时间(15、20、30min)脉冲电场刺激组则先表现为TH和DA的合成受到抑制,但随着培养时间的延长,其合成则被逐渐激活。采用蛋白激酶A(PKA)特异性抑制剂H-89和有丝分裂原活化蛋白激酶的激酶(MEK1/2)特异性抑制剂U0126,研究脉冲电场刺激所激活的与TH和DA合成相关的信号通路。结果表明,在没有神经生长因子(NGF)存在的情况下,PC12细胞主要通过PKA通路来激活TH的合成,低频脉冲电场刺激也主要激活PKA通路,因为抑制这条信号通路能显著抑制电场刺激所诱导的TH合成。     

Phosphorylation on tyrosine-15 of p34(Cdc2) by ErbB2 inhibits p34(Cdc2) activation and is involved in resistance to taxol-induced apoptosis

ErbB2 overexpression confers resistance to taxol-induced apoptosis by inhibiting p34(Cdc2) activation. One mechanism is via ErbB2-mediated upregulation of p21(Cip1), which inhibits Cdc2. Here, we report that the inhibitory phosphorylation on Cdc2 tyrosine (Y)15 (Cdc2-Y15-p) is elevated in ErbB2-overexpressing breast cancer cells and primary tumors. ErbB2 binds to and colocalizes with cyclin B-Cdc2 complexes and phosphorylates Cdc2-Y15. The ErbB2 kinase domain is sufficient to directly phosphorylate Cdc2-Y15. Increased Cdc2-Y15-p in ErbB2-overexpressing cells corresponds with delayed M phase entry. Expressing a nonphosphorylatable mutant of Cdc2 renders cells more sensitive to taxol-induced apoptosis. Thus, ErbB2 membrane RTK can confer resistance to taxol-induced apoptosis by directly phosphorylating Cdc2.     

嗜盐菌群对酸性金黄G的脱色特性和机理

【目的】为了获得能够在高盐环境下脱色偶氮染料的嗜盐菌群及其降解机理。【方法】采用富集驯化的方法获得一个嗜盐菌群,采用Illumina HiSeq2500测序平台对其群落结构进行测定;采用分光光度法测定了其降解特性;采用GC-MS和红外图谱分析了其降解机理;采用微核实验的方法比较了偶氮染料降解前后的毒性。【结果】该菌群在10%的盐度下,使100mg/L的酸性金黄G在8h内脱色。菌群主要由Zobellella、Rheinheimera、Exiguobacterium和Marinobacterium组成。最适宜的脱色条件是:pH=6,酵母粉为碳源,蛋白胨或硝酸钾作为氮源,盐度为1%–10%。酸性金黄G降解产物的毒性比降解前降低。酸性金黄G主要的降解产物是对氨基二苯胺和二苯胺。此外,该菌群还能使酸性大红GR和直接湖蓝5B等多种偶氮染料脱色,具有较好的脱色广谱性。【结论】获得了快速降解偶氮染料的嗜盐菌群及降解机理,为该嗜盐菌群应用于高盐印染废水的处理提供菌种资源和理论支持。     

人胃癌BGC-823细胞中去甲斑蝥素抑癌作用机理的蛋白质组学研究

去甲斑蝥素是我国自行研制的抗肿瘤药物,在临床上主要用于消化道肿瘤的治疗．实验表明,去甲斑蝥素可引起人胃癌BGC-823细胞发生 M期阻滞及细胞凋亡．进一步利用双向电泳和质谱技术,筛选出了去甲斑蝥素抑癌作用相关蛋白．研究显示,线粒体热休克蛋白CH60、线粒体ATP合酶d亚单位、内质网葡萄糖调节蛋白GRP78、线粒体Hsp70的辅助因子GRPE1、SH3L3以及染色质组装因子1小亚基RBBP4参与了去甲斑蝥素的抑癌作用．研究提示,去甲斑蝥素可能通过促进线粒体热休克蛋白及p53的表达进而激活caspase-3依赖的凋亡通路,并且去甲斑蝥素在引发内质网协迫之后,可通过抑制胞外信号调节激酶(extracellular signal regulated kinase, ERK)的活性促进肿瘤细胞的凋亡．进一步分析了去甲斑蝥素与线粒体ATP合酶抑制剂寡霉素A的联合用药对人胃癌细胞生长的影响,结果表明,联合用药的抑瘤效果比单独用药的抑瘤效果显著,提示去甲斑蝥素可能通过抑制线粒体ATP合酶功能抑制BGC-823生长．上述结果为优化去甲斑蝥素的联合用药方案提供了新线索．