人XPB基因在核苷酸剪切修复和基因转录中的分子机制

核苷酸剪切修复(NER)途径是维持生物体基因组稳定的重要机制。人着色性干皮病B组(xeroderma pigmentosum group B,XPB)基因又名ERCC3基因,它既是NER途径不可缺少的成员又是转录因子TFIIH的最大p89亚基。它是具有从3’端→5’端依赖ATP的单链DNA解旋酶活性的蛋白质,执行依赖DNA的ATP酶和解旋酶功能,在损伤DNA修复和基因转录中均起重要作用,并将两者有机偶联。该基因突变将导致3种不同的遗传疾病：着色性干皮病(xeroderma pigmentosum,XP),科凯恩氏综合征(cockayne’s syndrome,CS),毛发硫营养不艮(trichothiodystrophy,TTD)。其基因型通过在DNA修复和转录中的功能与表型联系起来。另外,XPB与p53存在物理和功能上的相互作用。现从XPB的3个方面即“一个基因,两种功能,3种疾病”作一综述。     

一株抗茶炭疽菌和魔芋镰刀菌的淀粉酶产色链霉菌的分离、鉴定及生防潜能

【背景】放线菌是一类重要的生防菌,具有强大的代谢活性,能产生抗生素、酶、酶抑制剂和激素等天然产物抑制病原物生长。【目的】从茶树根际分离得到放线菌,研究候选放线菌对茶炭疽菌和魔芋镰刀菌的抑菌活性及其生防潜能。【方法】分别以茶炭疽病致病菌Colletotrichum camelliae和魔芋茎腐病致病菌Fusarium solani为指示菌,采用土壤稀释涂布法、平板对峙法和菌丝生长速率法,从茶树根际土壤中分离、筛选拮抗放线菌,并根据菌株的形态特征、生理生化特性和系统发育分析结果对其进行分类鉴定,并开展候选放线菌的产促生相关物质和分泌细胞壁水解酶能力的定性检测试验。【结果】共分离得到14株拮抗放线菌,菌株A-dyzsc04-2的拮抗效果最强,被鉴定为淀粉酶产色链霉菌（Streptomyces diastatochromogenes）。该菌株的活菌体对C. camelliae和F. solani的抑制率分别为66.71%±1.23%和71.59%±2.46%,其无菌发酵滤液对2种指示菌的抑菌率均大于90%;此外,菌株A-dyzsc04-2还具有产嗜铁素和葡聚糖酶以及溶解无机磷的能力。【结论】菌株A-dyzsc04-2是一株优良的生防菌,具有较高的开发利用价值,研究结果为菌株A-dyzsc04-2防治茶炭疽病和魔芋茎腐病提供了理论支撑。     

The life style of Aureobasidium pullulans and the multiple forms of its polygalacturonase

The life style of Aureobasidium pullulans on pectin medium and its production of extracellular polygalacturonases are closely related. Polygalacturonases with random action pattern (EC 3.2.1.15) were formed in the first phases of cultivation, whereas exopolygalacturonases (EC 3.2.1.67) with terminal action pattern on pectin were produced during the whole growth of this yeast-like fungus. The production and inactivation of individual enzyme forms during cultivation were strongly dependent on the pH value of the pectin medium. Various kinds of stress can support the prolongation of the phase of endo-acting enzyme production, as well as the increase of their activity.     

水培经济植物对污水中磷的吸收利用及去除效果

对13种经济植物在污水水培条件下净化污水中磷的能力进行了研究。结果表明,黑麦草(Lolium multiflorum)、水芹(Oenanthe stolonifera)、莴苣(Lactuca sativavar.angustana)、酸模(Poly-gonum iapathifolium)、生菜(Lactuca sativa)、小葱(Allium ascalonicum)、五月慢青菜(Brassica chinen-sis)等品种具有较高的净化能力。在4个半月的水培中,TP的去除量分别达到10.27、10.35、6.5~6.896、.91、5.72、5.46和6.19 g.m-2;TP的去除率分别达到94.5%、95.2%、93.6%~99.3%、99.6%、99.5%、95%和89.2%。植物吸收作用是最主要的污水磷去除机制,沉淀在污水磷净化中的作用较小。污水中磷的去除与植物的生长期密切相关。黑麦草、水芹等7种植物适宜作为苏南地区冬季化粪池污水水培植物。     

花生ABI3同源基因的定位分析

ABSC ISIC AC ID-INSITIVE3(AB I3)、LEAFY COTYLEDON2(LEC2)和FUSCA3(FUS3)转录因子在种子发育过程中发挥着重要的调控作用。采用Northern杂交技术,用拟南芥AB I3保守的B3结构域部分序列作为探针分别与花生根、茎、叶、子叶RNA进行了杂交,同时也对花生根、茎、叶、子叶(含胚)组织切片进行了原位杂交,结果均显示只有在花生的子叶和胚中有杂交信号出现,表明花生中可能存在AB I3、FUS3和LEC2的同源基因,且它们只分布在花生的子叶和胚中。     

Lactic acid fermentation of Chinese yam (Dioscorea batatas Decne) flour and its pharmacological effect on gastrointestinal function in rat model

To develop a health-aid preparation of Chinese yam (Dioscorea batatas Decne), lactic acid fermentation was attempted using a mixed starter comprising ofLactobacillus acidophilus, Streptococcus thermophilus, andBifidobacterium bifidus. The anaerobic fermentation of a 5% Chinese yam flour suspension gave a uniform suspension of pH 4.35, containing 7.76×10⁶ CFU/mL lactic acid bacteria (LAB), and which was found to be acceptable to the panel from a sensory assessment. During the administration of the lactic acid fermented (LAF) Chinese yam to Sprague Dawley rats for 6 weeks, a smaller body weight gain, but greater excretion of feces were observed, implying the creation of a healthy gastrointestine on the administration of LAF Chinese yam, which was also confirmed by the gastrointestinal motility of the feed in rats fed on LAF Chinese yam. The constipation induced by loperamide was further suppressed in a rat group fed on a LAF Chinese yam diet, which was qualified from healthy gastrointestinal flora established by LAB. A serochemical analysis revealed a slight improvement in the blood glucose, neutral lipid and total cholesterol concentrations on administration of LAF Chinese yam, suggesting LAF Chinese yam could be served as a healthy-aid preparation, even for hyperglycemia or hyperlipidemia patients.     

Evaluation of formulations of Bacillus licheniformis for the biological control of tomato gray mold caused by Botrytis cinerea

Bacillus licheniformis N1, which has previously exhibited potential as a biological control agent, was investigated to develop a biofungicide to control the gray mold of tomato caused by Botrytis cinerea. Various formulations of B. licheniformis N1 were developed using fermentation cultures of the bacteria in Biji medium, and their ability to control gray mold on tomato plants was evaluated. The results of pot experiments led to the selection of the wettable powder formulation N1E, based on corn starch and olive oil, for evaluation of the disease control activity of this bacterium after both artificial infection of the pathogen and natural disease occurrence under production conditions. In plastic-house artificial infection experiments, a 100-fold diluted N1E treatment was found to be the optimum biofungicide spray formulation. This treatment resulted in the significant reduction of symptom development when N1E was applied before Bo. cinerea infection, but not after the infection. Both artificial infection experiments in a plastic house and natural infection experiments under production conditions revealed that the N1E significantly reduced disease severity on tomato plants and flowers. The disease control value of N1E on tomato plants was 90.5% under production conditions, as compared to the 77% conferred by a chemical fungicide, the mixture of carbendazim and diethofencarb (1:1). The prevention of flower infection by N1E resulted in increased numbers of tomato fruits on each plant. N1E treatment also had growth promotion activity, which showed the increased number of tomato fruits compared to fungicide treatment and non-treated control and the increased fruit size compared the non-treated control under production conditions. This study suggests that the corn starch-based formulation of B. licheniformis developed using liquid fermentation will be an effective tool in the biological control of tomato gray mold.     

Probiotic Bacillus amyloliquefaciens mediate M1 macrophage polarization in mouse bone marrow-derived macrophages

Depending on the microenvironment, macrophages can acquire distinct functional phenotypes, referred to as classically activated M1 and M2. M1 macrophages are considered potent effector cells that kill intracellular pathogens, and M2 macrophages promote the resolution of wound healing. In this study, we are interested to know whether probiotic Bacillus amyloliquefaciens (Ba) can induce macrophages polarization. Real-time fluorescence PCR analysis demonstrated that the expression of IL-1β, iNOS, TNF-α and IL-6 genes for M1 macrophages was significantly increased at 1.5 h after probiotic Ba treatment compared to the probiotic Ba-free treatment (P < 0.01), whereas the expression of M2 macrophage marker genes (Arg1, Fizz1, MR, Ym1) was decreased (P < 0.05). Furthermore, the phagocytic activity was dramatically increased in the Ba-treated BMDMs using a FITC-dextran endocytosis assay. Together, these findings indicated that probiotic Ba facilitated polarization of M1 macrophages and enhanced its phagocytic capacity. The results expanded our knowledge about probiotic function-involved macrophage polarization.     

开放条件下烟管菌XX-2对孔雀石绿染料的高效降解

[目的]评价白腐真菌Bjerkandera adusta XX-2处理孔雀石绿染料废水的能力,为其在染料废水中的应用提供参考依据.[方法]采用批次实验在开放条件下研究通气、pH、温度、染料初始浓度、培养时间、碳源、氮源、金属离子、盐度等因子对该菌降解孔雀石绿的影响.同时利用植物萌发、微生物抑菌和水生动物致死实验对降解产物进行毒性测试.[结果]B.adusta XX-2菌株在开放的非灭菌条件下也能高效降解孔雀石绿.例如,在初始浓度为120 mg/L且以孔雀石绿为唯一营养源的条件下降解率也能达到60％.静置培养和摇动培养呈现出几乎相同的降解率,这可以为技术应用节约动力成本.最适降解pH与温度分别为7.0和25℃.在上述参数体系的优化基础上,分别进行了碳源、氮源与金属离子的添加优化实验,结果显示低浓度的碳源(如柠檬酸钠)、氮源(如氯化铵)和金属离子(如Zn2+)均可大大提高B.adusta XX-2对孔雀石绿的脱色效率.同时B.adusta XX-2的降解也能在很高的盐浓度下进行.毒性测试表明降解后的染料对植物、微生物、水生生物的毒性大大减少.[结论]B.adusta XX-2菌株在处理染料废水方面具有很大的应用潜力.     

Down-regulation of human cytomegalovirus UL138, a novel latency-associated determinant, by hcmv-miR-UL36

MicroRNAs (miRNAs) are small RNAs, 19–23 nucleotides in length, which regulate a variety of cellular processes. Human cytomegalovirus (HCMV) encodes only one intronic miRNA: human cytomegalovirus microRNA UL36 (hcmv-miR-UL36). In this study, we found that over-expression of hcmv-miR-UL36 resulted in a more than threefold increase in HCMV DNA synthesis at 24 h post infection. Fifteen putative targets of hcmv-miR-UL36 were identified using hybrid PCR, one being the HCMV UL138 gene that has previously been identified as a novel latency-associated determinant of HCMV infection. Down-regulation of UL138 expression by hcmv-miR-UL36 was validated using luciferase reporter assays and Western blot analysis in HEK293 cells. In the presence of hcmv-miR-UL36, we observed a 74.6% decrease in luciferase activity and a 46.2% decrease in HCMV UL138 protein expression. Our results indicate that hcmv-miR-UL36 may be a viral miRNA contributing to HCMV replication.