纤维堆囊菌的多细胞形态发生过程

粘细菌是具有复杂多细胞行为的革蓝氏阴性细菌,纤维堆囊菌是粘细菌中唯一能够降解纤维素的粘细菌种属。本文通过扫描电子显微镜和相差光学显微镜,分析了纤维堆囊菌在纤维素基质上的生长和子实体形态发生的多细胞行为特征,给出了生长和子实体发育的模式图谱。     

碳源和氮源对玫瑰栗色链霉菌No．336产葡萄糖异构酶的影响

玫瑰粟色链霉菌(Streptomyces rosecocastaneus) No. 336变异株对碳源或氮源的利用及其和产葡萄糖异构酶的关系,用半合成培养基进行了摇瓶液体培养试验。测定以15种单精和糖醇、8种寡糖和5种多糖作为碳源,6种含氮化合物作为氮源对菌的生长和产酶的影响。证明N。．336菌株除利用L一阿拉伯糖和D二木糖等五碳糖作为碳源外,也能利用D一葡萄糖等六碳糖作为碳源和能源。糖醇对酶的形成或无明显影响,或有抑制作用。在供试的氮源中,玉米浆和酵母膏对产酶的影响明显优于蛋白胨,该菌几乎不能以无帆氮化合物或乙酸镶作为唯一的氮源。C／N比的试验表明,2：1、1：1或3：1的培养基组成有利于葡萄糖异梅酶的形成,提高氮素含量虽能促进菌的生长,但对产酶不利。以麦麸水解液和玉米浆为主要成分的培养基有利于No.336菌株的生长和产酶,每毫升培养液的酶活力在180单位以上。     

浓香型酒窖中生丝微菌的分离与特性

从浓香型大曲酒发酵糟中,首次分离到一株能利用甲醇为唯一碳源和能源的生丝微菌Hy-phomicrobium sp M7。该菌具有独特的形态学特征:细胞顶端常生长一根菌丝结构。通过菌丝出芽而繁殖。细胞呈卵圆形,单独存在。菌落淡褐色。该菌对甲醇有较大的亲和力。在甲醇存在时,能以NO_3~-为电子受体进行厌氧生长。能利用甲醇、甲胺类化合物、乙醇、乙酸盐作为碳源生长,不利用c_2以上的有机物。在乙醇为碳源的培养基上,菌丝顶端常长出一种喇叭口结构。最适氮源为NH_4~+,酒糟浸液、酵母膏对生长有促进作用。该菌不同于文献报道的已知种。讨论了该菌在酒窖中存在的生态意义。     

碳源和氮源对彩绒革盖菌Coriolus versicolor木质纤维素酶和木质素酶分泌的影响

研究了彩绒草盖菌在不同碳源和氮源培养基中生长时,对纤维素酶、半纤维素酶、木质素酶（漆酶、多酚氧化酶、愈创木酚氧化酶）分泌的影响。结果表明不同碳源和氮源对酶类的分泌影响很大,富含淀粉的物质能明显促进木质素酶的分泌,而专一性底物（纤维素和半纤维素）对纤维素酶和半纤维素酶有诱导作用,麸皮也能诱导半纤维素酶的产生。     

一株新粘细菌生物学性质的研究

对粘细菌纤维堆囊菌So ce cpu-1生物学特性进行了研究.结果表明,该粘细菌能利用如滤纸或玉米秸杆等纤维素.So ce cpu-1次级代谢产物的抑茵实验表明,该粘细菌具有广谱抗菌活性:对人白血病细胞K562有较好的抑制效果.     

浓香型酒窖中生丝微菌的分离与特性*

从浓香型大曲酒发酵糟中,首次分离到一株能利用甲醇为唯一碳源和能源的生丝微菌Hy-phomicrobium sp M7。该菌具有独特的形态学特征:细胞顶端常生长一根菌丝结构。通过菌丝出芽而繁殖。细胞呈卵圆形,单独存在。菌落淡褐色。该菌对甲醇有较大的亲和力。在甲醇存在时,能以NO3-为电子受体进行厌氧生长。能利用甲醇、甲胺类化合物、乙醇、乙酸盐作为碳源生长,不利用C₂以上的有机物。在乙醇为碳源的培养基上,菌丝顶端常长出一种喇叭口结构。最适氮源为NH相似文献   

扣囊复膜孢酵母b-葡萄糖苷酶基因在工业酿酒酵母中的表达

本文以工业酿酒酵母菌株( Saccharomyces cerevisiae Y )为研究对象,针对其复杂的生理生化遗传特性,建立了相对应的转化体系。以pRS41H质粒为基础载体,构建了含有工业酿酒酵母自身的gpd2启动子、终止子和扣囊复膜孢酵母的b-葡萄糖苷酶基因bgl的重组质粒pRS-gb。电击转化进入工业酿酒酵母细胞,潮霉素抗性筛选,获得重组菌。该重组菌可以在以纤维二糖为唯一碳源的培养基中生长,培养36 h,b-葡萄糖苷酶酶活达到0.967 u/ml。以纤维二糖为唯一碳源的酒精发酵中,酒精度可以达到0.92 g/l。这对工业生产中利用纤维素为原料发酵生产酒精具有重要意义。     

通过碳源与氮源研究白腐菌产漆酶和菌丝体生长的相关性

通过碳源与氮源对白腐菌产漆酶和菌丝体生长的影响 ,定性地研究了白腐菌产漆酶和菌丝体生长的关系。碳源中淀粉最能提高菌丝体的生长量 ,麦芽糖是促进漆酶分泌的最好碳源。氮源中的酒石酸铵能较好地促进漆酶的分泌 ,但几种氮源对菌丝体生长的影响不是很明显。研究显示白腐菌的生长和酶的分泌不同步 ,也不成正相关。     

贵州白柄鸡Zong菌菌丝体培养条件研究

本文报道筛选了优良的固体培养基配方,对不同ｐＨ值、温度、碳源、氮源条件下白柄鸡Ｚｏｎｇ菌菌丝体的生长进行测定。结果表明：白柄鸡Ｚｏｎｇ菌以碳源葡萄糖、氮源花生 、ＰＨ４．６、温度３０℃淡最适生长条件。目前,白柄鸡Ｚｏｎｇ菌在实验室条件下生长良好,这对人工栽培和利用白柄鸡Ｚｏｎｇ菌具有实际经济意义。     

球毛壳菌降解天然木质纤维素能力差异及酶系基因分析

目的:以不同植物中分离到的4株内生球毛壳菌NK102、NK103、NK104和NK105为对象,研究不同生态来源球毛壳菌降解木质素和纤维素的能力。方法:首先采用羧甲基纤维素和纤维素刚果红平板检测各菌株的纤维素降解能力,并利用Bavendamm平板反应检测各菌株的木质素降解能力;将4株菌分别培养在以微晶纤维素、杨树叶和木屑为惟一碳源的液体培养基中,通过检测培养液中纤维素酶和漆酶的酶活力,比较各菌株分解利用天然木质纤维素材料的能力,连续培养12 d后检测培养液中次级代谢产物的合成情况;利用已测序的球毛壳菌CBS148.51的基因组信息,寻找编码木质纤维素降解酶类的基因,为球毛壳菌分解利用木质纤维素提供分子生物学依据。结果:NK102、NK103、NK104和NK105在羧甲基纤维素培养基和纤维素刚果红培养基上都能够生长并形成水解圈;Bavendamm平板反应显示4株菌降解木质素的能力由强到弱依次是NK103、NK102、NK105和NK104。4株菌都能分解利用微晶纤维素、杨树叶和木屑,分泌纤维素酶和漆酶,其中NK102在以木屑为碳源的培养基上纤维素酶活力最强,达到0.76 U/mL发酵液,NK103在以杨树叶为碳源的培养基上漆酶活力最强。与此同时,4株菌在发酵培养过程中都能够稳定地合成球毛壳甲素(ChA),ChA产量受到碳源影响,在以杨树叶为碳源的培养基上,NK104的ChA产量最高,可达到14.88 mg/L发酵液。利用已测序的球毛壳菌CBS148.51的基因组信息,寻找到119个编码纤维素半纤维素酶的基因、8个编码漆酶的基因和2个编码锰过氧化物酶的基因,球毛壳菌具有完整的降解纤维素半纤维素的酶体系,在木质纤维素降解真菌的开发过程中具有重要的研究价值。结论:本研究为球毛壳菌木质纤维素降解过程的研究及该菌种的开发利用奠定了基础。     

纤维堆囊菌的供谢产物及其生物学活性分析

纤维堆囊菌不同菌株不但表现细胞和子实体形态的差异,而且供谢产物的组成和生物学活性也存在差异。纤维堆囊菌对革兰氏阴性细菌不表现任何抑制活性,部分菌株可抑制革兰氏阳性细菌;但所有菌株对真菌和肿瘤细胞有广泛和强烈的抑制作用。薄层层析显示,纤维堆囊菌的次级代谢产物组分较多,且大多数组分具有不同程度的抑制真菌和肿细胞的活性。在筛选中发现四株菌的代谢产物能够促进微管蛋白聚合,其中So33-1活性组分的薄层层析Rf值与已知的Epothilone A相似,而So81的则有较大的差异。研究结果表明纤维堆囊菌是很好的筛选抗真核生物活性的天然化合物资源。     

Nutrient regulation of epothilone biosynthesis in heterologous and native production strains

Fermentation media with different initial concentrations of ammonium and phosphate salts were used to study the inhibitory effects of those ions on growth and production of epothilone in Sorangium cellulosum and Myxococcus xanthus. The native epothilone producer, S. cellulosum was more sensitive to ammonium and phosphate than the heterologous producer, M. xanthus. An ammonium concentration of 12 mM reduced epothilone titers by 90% in S. cellulosum but by only 40% in M. xanthus. When 5 mM phosphate was added to the medium, production in both strains was 60% lower. Higher phosphate concentrations had little additional effect on M. xanthus titers, but epothilone production with 17 mM extra-cellular phosphate in S. cellulosum was 95% lower than in the control condition. The effect of iron supplementation to the fermentation medium was also investigated. Both strains showed best production with 20 microM iron added to the medium.     

Critical variations of conjugational DNA transfer into secondary metabolite multiproducing Sorangium cellulosum strains So ce12 and So ce56: development of a mariner-based transposon mutagenesis system

Myxobacteria increasingly gain attention as a source of bioactive natural products. The genus Sorangium produces almost half of the secondary metabolites isolated from these microorganisms. Nevertheless, genetic systems for Sorangium strains are poorly developed, which makes the identification of the genes directing natural product biosynthesis difficult. Using biparental and triparental mating, we have developed methodologies for DNA transfer from Escherichia coli via conjugation for the genome sequencing model strain So ce56 and the secondary metabolite multiproducing strain So ce12. The conjugation protocol developed for strain So ce56 is not applicable to other Sorangium strains. Crucial points for the conjugation are the ratio of E. coli and Sorangium cellulosum cells, the choice of liquid or solid medium, the time used for the conjugation process and antibiotic selection in liquid medium prior to the plating of cells. A mariner-based transposon containing a hygromycin resistance gene was generated and used as the selectable marker for S. cellulosum. The transposon randomly integrates into the chromosome of both strains. As a proof of principle, S. cellulosum So ce12 transposon mutants were screened using an overlay assay to target the chivosazole biosynthetic gene cluster.     

Multi parameter in vitro testing of ratjadone using flow cytometry

Ratjadone, isolated from the myxobacterium Sorangium cellulosum, belongs to the family of so-called orphan ligands, which includes leptomycin, callystatin and other compounds. In previous screening tests, ratjadone revealed a growth inhibitory effect against bacteria, yeast and human cancer cells. Following these first results, ratjadone was tested on several human tumour cell lines (Jurkat, HepG2, U87-MG) and, as a control, on a non-tumour cell line (RLC18) for its mode of action. The cell analysis was carried out by flow cytometry. This comprised cell density measurements, live-dead analysis, cell-cycle analysis and detection of apoptosis. First experiments confirmed the growth inhibitory effect on any chosen tumour cell line. Following these results a dose effect relationship was monitored, confirming the high effectiveness of ratjadone against cell growth at nanomolar concentration. Cell cycle analysis has shown that ratjadone intervenes in the cell cycle by arresting the cells in G1-phase. Biological testing of additional ratjadone derivatives with changed configuration and stereochemistry, identified the pharmacophoric site of the molecule.     

应用优化的双向电泳技术建立纤维堆囊菌So0157-2蛋白质组数据库

堆囊菌丰富的次级代谢产物是新药的重要来源,而蛋白质组学分析是研究代谢调控的有效方法．然而堆囊菌含有大量的胞外多糖以及黏液,干扰了蛋白质组学分析中蛋白质的溶解度、分辨率及重现性．为了高通量地筛选Sorangium cellulosum So0157-2表达的特异性蛋白,实验优化了S. cellulosum So0157-2双向电泳方法．首先,S. cellulosum So0157-2蛋白在裂解液中有更好的溶解度．pH 3～10非线性胶条和1 mg的蛋白上样量适用于第一向等电聚焦,分别提高了蛋白质点的分辨率和低丰度蛋白质的表达．15% SDS-PAGE 改善了S. cellulosum So0157-2蛋白分离的分辨率和重现性．最终,通过优化的双向电泳方法获得了S. cellulosum So0157-2 在M26培养基中培养3天的全蛋白质表达谱,并检测到552个蛋白质点．进而对表达蛋白通过MALDI-TOF-MS进行质谱鉴定,其中474个蛋白质得到鉴定,鉴定率85.9%．得到鉴定的蛋白质包括细胞结构和功能组分,以及细胞代谢合成酶类,其中8个蛋白质与糖类的转化和代谢相关,这有助于糖基化埃博霉素A的深入研究．该优化方法为进一步建立纤维堆囊菌So0157-2在各种培养条件下的蛋白质组表达数据库打下基础．     

Distribution of Sorangium cellulosum

The myxobacterium Sorangium cellulosum exists and plays an important role in soil ecology by its ability to degrade cellulosic materials; it was found to be widely distributed in North American soils.     

Production of an exopolysaccharide bioflocculant by Sorangium cellulosum

AIMS: To isolate a new exopolysaccharide bioflocculant produced by the myxobacterium Sorangium cellulosum NUST06, and to characterize its chemical composition and expolysaccharide production relative to carbon source. METHODS AND RESULTS: Exopolysaccharide levels and biomass production by S. cellulosum NUST06 were analysed relative to carbon source. Glucose in the medium at a level of 3 g l(-1) completely inhibited cell growth and exopolysaccharide production, but low concentrations of glucose (1-2 g l(-1)) could stimulate cell utilization of starch. The chemical composition and flocculating activity of the NUST06 exopolysaccharide was investigated. The flocculant comprised 38.3% proteins and 58.5% carbohydrates, of which glucose, mannose and glucuronic acid were present at 51.3%, 39.2% and 10.5%, respectively. The flocculating activity of the NUST06 flocculant depended strongly on cations. CONCLUSIONS: It is feasible to produce an exopolysaccharide bioflocculant by the strain NUST06 in a mineral salts medium using starch as a carbon source. SIGNIFICANCE AND IMPACT OF THE STUDY: This strain may be advantageous for commercial bioflocculant production and may enrich existing knowledge of myxobacteria.     

Improving conjugation efficacy of <Emphasis Type="Italic">Sorangium cellulosum</Emphasis> by the addition of dual selection antibiotics

The conjugation protocols in myxobacterium Sorangium cellulosum are often inapplicable due to the strain-specific sensitivity to the presence of Escherichia coli cells or the resistances to many antibiotics. Here we report that the conjugative transfer of the mobilizable plasmid pCVD442 from E. coli DH5alpha (lambda pir) to Sorangium strains could be greatly increased by the presence of low doses of dual selection antibiotics in the mating medium. The improvement was efficient in either E. coli-tolerant or sensitive Sorangium strains. For those phleomycin and hygromycin tolerant Sorangium strains, chloramphenicol-resistance gene was developed as a new selectable marker by driving the resistance gene with the aphII promoter. Using the improved protocol, the epothilone biosynthetic pathway was inactivated by an insertion mutation in the biosynthetic genes of the producing Sorangium strains.     

天然抗癌药物Epothilones研究进展

本文综述了近几年来国际上对纤维素堆囊菌分泌的天然抗癌化合物epothilones的研究进展。其中 ,简要介绍了 epothilones的由来、化学结构、合成方法 ,着重介绍了 epothilone与 Taxol在微管聚合特性上的性能比较。