西泉眼水库夏季浮游动物群落结构特征及水质评价

2010年夏季,对西泉眼水库浮游动物及水质理化指标进行了调查。分析了该水库浮游动物群落结构特征,运用现存量法、指示生物法、多样性分析法、Q_(B/T)指数法、E/O指数法、肥度指数法(E')和理化因子分析法评价了水质等级,应用典范对应法分析了浮游动物与环境因子之间的相关性。结果表明:浮游动物56种,优势种为褐砂壳虫Difflugia avellana、长三肢轮虫Filinia longiseta、针簇多肢轮虫Polyarthra trigla、微刺小剑水蚤Microcyclops inchoatus和无节幼体;污染指示种53种,丰度为46.13个/L,生物量为0.137mg/L;Shannon-Wiener指数为2.78,Margalef丰富度指数为1.97,Q_(B/T)指数为2.0,E/O指数为3.2,肥度指数(E')为2.28。评价结果表明,该水库已处于中度污染状态,水体处于中富营养化水平,NO_3~-、NO_3-N、Cl~-、COND、Depth、NH_4~+、TP和Chla是影响浮游动物种群数量及分布的主要环境因子,作为水源地其水质还需进一步加强管理与调控。     

FBXO2, a novel marker for metastasis in human gastric cancer

FBXO2 belongs to the F-box family of proteins, is a cytoplasmic protein and ubiquitin ligase F-box protein with specificity for high-mannose glycoproteins. Recently published studies indicate that other members of the F-box family, such as SKP2 and FBXW7, are involved in the development of gastric cancer. The role of FBXO2 in the process of tumorigenesis, including gastric cancer, is still unknown. In this study, we show that the level of FBXO2 is highly correlated with lymph node metastasis, and that overall survival (OS) of patients with high FBXO2 expression is significantly shorter than patients with low FBXO2 expression. FBXO2 promoted the proliferation and migration of human gastric cancer cells, whereas knockdown of FBXO2 by siRNA led to a decrease in those activities. Down-regulating FBXO2 reduced epithelial-mesenchymal transition (EMT) in gastric cancer cells, with increased expression of E-cadherin and decreased expression of N-cadherin and vimentin. In summary, our findings suggest that FBXO2-regulated EMT led to carcinogenicity in gastric cancer and may be a novel target in the diagnosis and treatment of gastric cancer.     

蝇蛆肠道微生物菌群对猪粪残留抗生素的降解及抗性基因的影响

【目的】过度使用抗生素作为动物饲料添加剂,导致畜禽粪便已成为抗生素抗性基因的主要蓄积库,为了研究蝇蛆(Musca domestica)对猪粪中残留抗生素及抗性基因的影响,本文动态采集了实际农场条件下蝇蛆转化过程中猪粪堆体及虫体样本。【方法】利用q PCR、液相色谱-电喷雾质谱、同位素内标法、Illumina高通量测序以及局部相似性研究蝇蛆生物转化过程中残留抗生素降解效能及相关抗性基因组变化的微生物生态机制。【结果】6 d周期内,猪粪中四环素、土霉素、金霉素、强力霉素、磺胺嘧啶、诺氟沙星、氧氟沙星、环丙沙星以及恩诺沙星等9种残留抗生素含量显著下降,累积减量为34.3%–58.1%,每日减量百分比介于7.8%–57.4%之间。猪粪中共检测到的158种抗性基因,其中有118种大幅衰减,衰减量平均达79.3%;23种抗性基因存在富集现象,富集倍数平均为3.48。在蝇蛆肠道的作用下,粪源微生物群落中Bacteroidetes相对丰度下降,Proteobacteria相对丰度增加,尤其是Ignatzschineria增幅最大。网络分析发现,抗性基因的增减与微生物群落的变化显著相关,与抗性基因衰减相关的微生物主要属于Clostridiales和Bacteroidales,而与抗性基因富集相关的微生物主要为Alcaligenaceae、[Weeksellaceae]及Bacillales。【结论】蝇蛆可有效削减猪粪中的残留抗生素及防控抗性基因向环境扩散。     

NLRP3 Inflammasome Is Involved in Q-VD-OPH Induced Necroptosis Following Cerebral Ischemia-Reperfusion Injury

Necroptosis is a manner of caspase-independent cell death,which accounts for delayed ischemic cerebral injury, and can be used as a novel tool to expand the treatment time window in ischemic cerebral injury. Q-VD-OPH, a novel pan caspase inhibitor, has been identified as an inducer of necroptosis. In this study, we determined the optimal dose of Q-VD-OPH, which induces necroptosis in rats by the middle cerebral artery occlusion, followed by reperfusion. Furthermore, we report that the NLRP3 inflammasome is involved in necroptosis, with levels of NLRP3 inflammasome proteins as well as inflammatory cytokines, such as IL-1β, being elevated. We also demonstrated that NLRP3 was not only expressed in microglia and vascular endothelial cell, but also in neurons when necroptosis is induced with Q-VD-OPH. Inhibition of NLRP3 by glyburide strongly suppressed the expression of NLRP3 inflammasome proteins and IL-1β, and markedly reduced brain tissue damage. Our findings provide evidence that pretreatment with Q-VD-OPH suppresses apoptosis and induces necroptosis in the cerebral ischemia-reperfusion model. We also identified that the NLRP3 inflammasome plays an important role in neuronal necroptosis, and that NLRP3 inflammasome deficiency reduces brain tissue damage after cerebral ischemia-reperfusion injury in rats.     

Lactotransferrin is the major estrogen inducible protein of mouse uterine secretions

Antibody to an estrogen inducible mouse uterine protein (Teng, C. T., Walker, M. P., Bhattacharyya, S. N., Klapper, D. G., DiAugustine, R. P., and McLachlan, J. A. (1986) Biochem. J. 240, 413-422) has been used to isolate cDNA to the messenger RNA. Analysis of the deduced primary structure and additional biochemical characterization indicates that the protein is lactotransferrin. An increase in the level of lactotransferrin mRNA of at least 300-fold can be induced in the mouse uterus by estrogen. In contrast, the mRNA is virtually undetectable in rat uterine tissue following estrogen administration. The estrogenic stimulation in mouse uterus contrasts with the known prolactin dependence in mammary gland.     

高糖膳食对大鼠载脂蛋白AⅠ、CⅡ和CⅢ基因表达的影响

 我们以Sprague-Dawley大鼠为实验对象,研究高糖膳食对大鼠肝脏及小肠载脂蛋白(apo)AⅠ、CⅡ和CⅢmRNA相对含量的影响。摄取高糖膳食6天后,大鼠空腹血清TG含量和胰岛素水平均显著升高,cAMP含量则显著下降。同时,用RNA斑点杂交技术分析表明,摄取高糖膳食6天后,肝脏apoAⅠCⅡ和CⅢmRNA相对含量均显著下降(P<0.01,P<0.05);小肠apoAⅠ和CⅡmRNA相对含量也显著下降(P<0.05,P<0.01),但小肠apoCⅢmRNA相对含量无改变。     

The molecular structure of the complex of Hoechst 33258 and the DNA dodecamer d(CGCGAATTCGCG).

The crystal structure of the complex between the dodecamer d(CGCGAATTCGCG) and a synthetic dye molecule Hoechst 33258 was solved by X-ray diffraction analysis and refined to an R-factor of 15.7% at 2.25 A resolution. The crescent-shaped Hoechst compound is found to bind to the central four AATT base pairs in the narrow minor groove of the B-DNA double helix. The piperazine ring of the drug has its flat face almost parallel to the aromatic bisbenzimidazole ring and lies sideways in the minor groove. No evidence of disordered structure of the drug is seen in the complex. The binding of Hoechst to DNA is stabilized by a combination of hydrogen bonding, van der Waals interaction and electrostatic interactions. The binding preference for AT base pairs by the drug is the result of the close contact between the Hoechst molecule and the C2 hydrogen atoms of adenine. The nature of these contacts precludes the binding of the drug to G-C base pairs due to the presence of N2 amino groups of guanines. The present crystal structural information agrees well with the data obtained from chemical footprinting experiments.     

枯草芽孢杆菌(Bacillus subtilis)Tpb55灌根与烟草根围细菌多样性变化的相关性北大核心CSCD

【目的】利用454高通量测序技术分析生防菌株枯草芽孢杆菌(Bacillus subtilis)Tpb55对烟草根围土壤细菌群落的影响;同时测定施加Tpb55处理对烟草黑胫病的大田防效。【方法】试验设置Tpb55菌剂108 CFU/m L灌根和空白对照2个处理,分别在处理0、10、22 d采集烟草根围土壤,提取土壤细菌总DNA,扩增细菌16S r DNA V1-V3区,对扩增产物进行454高通量测序,使用Qiime软件分析不同处理的细菌群落结构。【结果】对照和处理样品测序后共获得了41207个优质序列,鉴定属于细菌的25个门。所有样品中优势菌群均为放线菌门(Actinobacteria)、变形菌门(Proteobacteria)和酸杆菌门(Acidobacteria)。在病情发展过程中,放线菌门的细菌丰度逐渐下降,变形菌门含量呈上升趋势。施用Tpb55后,酸杆菌门含量明显上升并高于对照。对照中芽孢杆菌科(Bacillaceae)和多样性指示菌草酸杆菌科(Oxalobacteraceae)的细菌丰度均明显下降,Tpb55处理的样品中芽孢杆菌科含量不断上升,草酸杆菌科含量相对稳定。Chao1、ACE和Shannon指数分析表明,Tpb55处理的样品中细菌多样性和丰富度不断提高且高于对照。Tpb55处理后10 d和22 d,OTU序列数据库中与Tpb55 16S r DNA V1-V3区PCR产物高度同源OTU数目分别为31和45。Tpb55处理的烟草黑胫病病情指数(5.29)显著低于对照(38.52)。【结论】施用Tpb55可以提高根围土壤细菌多样性和群落结构稳定性,这可能是其发挥良好生防作用的重要机制之一。     

Whole genomic DNA sequencing and comparative genomic analysis of Arthrospira platensis: high genome plasticity and genetic diversity

Arthrospira platensis is a multi-cellular and filamentous non-N2-fixing cyanobacterium that is capable of performing oxygenic photosynthesis. In this study, we determined the nearly complete genome sequence of A. platensis YZ. A. platensis YZ genome is a single, circular chromosome of 6.62 Mb in size. Phylogenetic and comparative genomic analyses revealed that A. platensis YZ was more closely related to A. platensis NIES-39 than Arthrospira sp. PCC 8005 and A. platensis C1. Broad gene gains were identified between A. platensis YZ and three other Arthrospira speices, some of which have been previously demonstrated that can be laterally transferred among different species, such as restriction-modification systems-coding genes. Moreover, unprecedented extensive chromosomal rearrangements among different strains were observed. The chromosomal rearrangements, particularly the chromosomal inversions, were analysed and estimated to be closely related to palindromes that involved long inverted repeat sequences and the extensively distributed type IIR restriction enzyme in the Arthrospira genome. In addition, species from genus Arthrospira unanimously contained the highest rate of repetitive sequence compared with the other species of order Oscillatoriales, suggested that sequence duplication significantly contributed to Arthrospira genome phylogeny. These results provided in-depth views into the genomic phylogeny and structural variation of A. platensis, as well as provide a valuable resource for functional genomics studies.