Lipids of sulfate-reducing bacteria and sulfur-oxidizing bacteria found in the Dongsheng uranium deposit

U-bearing sandstones from the Dongsheng deposit in Ordos Basin contain abundant C15-C18 fatty acids. The fatty acids may have been derived from modern and ancient organisms including organisms from the intervals of U mineralization. A certain amount of i15:0, a15:0, a17:0 fatty acids coexist with small amounts of i17:1ω7c and 10me16:0, characteristic biomarkers of Desulfovibrio and Desulfobacter sp., respectively. This indicates the existence of sulfate-reducing bacteria (SRB) in the sandstones. The presence of sulfur-oxidizing bacteria (SOB), such as Beggiatoa and Thioploca, is indicated by significant amounts of 16:1ω7c and 18:1ω7c fatty acids. The existence of the SRB in the deposit, as inferred from the fatty acids, is consistent with results from fossilized microorganisms and isotopic compositions of ore-stage pyrite. This suggests that the environment may have been favorable for the SRB to grow since ore formation (9.8-22 Ma). The bacteria may have degraded hydrocarbons directly, or indirectly utilized hydrocarbons degraded by oxic microbes in the deposits. This process may have produced 12C-rich calcite and prominent baseline humps of unresolved complex mixtures (UCM), and 25-demethylated hopanes and tricyclic terpanes. The existence of sulfur-oxidizing bacteria and sulfate-reducing bacteria in the deposit may have resulted in bacterial sulfate reduction to sulfide, re-oxidization of the sulfide to sulfate and subsequent reduction of the sulfate to sulfide. This assertion is supported by ore-stage pyrite with δ34S values as low as-39.2‰, and the lightest sulfate (about 11‰) measured during the Phanerozoic, a difference of more than 46‰.     

一株氨化菌的分离鉴定及其氨化特性研究

从升流式厌氧污泥床(UASB)中分离到一株高效氨化菌AHJ1,通过形态观察、生理生化试验、16S rRNA基因序列分析,初步鉴定为球形芽孢杆菌;进一步探讨了UASB处理工艺各因素对AHJ1氨化特性的影响,结果表明在温度37℃,pH 6.0、装液量30%,氨化率可达58.62%,且在一定程度上抑制了厌氧处理中鸟粪石的生成.     

Biogenesis of β-barrel membrane proteins in bacteria and eukaryotes: evolutionary conservation and divergence

Membrane-embedded β-barrel proteins span the membrane via multiple amphipathic β-strands arranged in a cylindrical shape. These proteins are found in the outer membranes of Gram-negative bacteria, mitochondria and chloroplasts. This situation is thought to reflect the evolutionary origin of mitochondria and chloroplasts from Gram-negative bacterial endosymbionts. β-barrel proteins fulfil a variety of functions; among them are pore-forming proteins that allow the flux of metabolites across the membrane by passive diffusion, active transporters of siderophores, enzymes, structural proteins, and proteins that mediate protein translocation across or insertion into membranes. The biogenesis process of these proteins combines evolutionary conservation of the central elements with some noticeable differences in signals and machineries. This review summarizes our current knowledge of the functions and biogenesis of this special family of proteins.     

窖泥己酸菌的分离培养与诱变选育

泥窖己酸菌产生的己酸是浓香型大曲酒主体香成分的前体物质之一。从老窖泥中分离纯化出一株产酸能力较高的己酸菌GS5,以其为亲株,通过紫外诱变(照射功率15W,照射距离30cm,时间为3m in),筛选到1株产酸量提高12%的突变株GSUT3,多次继代培养结果表明其产量稳定。研究还发现GSUT3与亲株之间,GSUT3第1代与第8代之间,其生长变化规律和己酸产量的变化规律表现一致。     

醋酸菌液态发酵产酸的研究

通过正交试验探讨了醋酸菌液态发酵产酸的最佳配方及工艺。     

中华绒螯蟹Eriocheir sinensis幼体丝状细菌的扫描电镜观察

应用扫描电间对中华绒螯蟹幼体附着的丝状细菌进行了详细的观察，结果表明，丝状细菌只附生于幼体表面，没有明显伸入体内的结构，丝状细菌行裂殖生殖，生长繁殖所需营养直接摄取自水环境，并对其危害性以及防治等方面进行了探讨。     

红假单胞菌的分离及菌种保存试验研究

从不同来源的样品中分离出四株光合细菌 ,经鉴定均属于红假单胞菌 ,同时分别采用液体种自然条件下、液体种蜡封、穿刺物蜡封、砂土管等方法对其菌种进行了保存试验研究 ,最后得出两种最佳保存方法 :蜡封液体试管种法和试管穿刺蜡封法     

氢细菌固定CO2反应动力学研究

研究了分批培养条件下固定CO2氢细菌的生长及底物消耗动力学特性，结果表明，最佳气相比为V（H2）：V（O2）：V（CO2）=3.5:1.0:1.0;在30℃、pH=7.0的条件下培养40h，每mL培养基菌体干质量达1.6mg，每g细胞干质量含蛋白量为718mg。菌体产率分别为Y（H2）=3.00,Y(O2)=0.65和Y（CO2）=0.54，并得到了菌生长和底物消耗模型。     

光合细菌中类胡萝卜素的提取及性质的研究

确立了光合细菌ＰＳＢ－Ｈ 的最佳提取工艺条件为：以７∶２ 的丙酮－甲醇液为溶剂，用量２５ｍ Ｌ／４０ｍ Ｌ发酵液，２ ｈ，一次浸提，再经进一步的分离和纯化，得到类胡萝卜素纯品。并对提取后的类胡萝卜素的性质进行了进一步的探讨：具有双键烯烃的一般性质，耐热性较好，需置于暗处保存，在紫外防护试验中，当其质量浓度达到０．１ ｍ ｇ／Ｌ时，就有显著的防护作用     

一株磷细菌发酵条件的研究

对一株磷细菌的发酵条件进行了研究。其中，单因素发酵试验表明，碳源以2％的淀粉最佳，氮源以0．1％的NH4CI最好。最适培养温度为37℃，最适初始pH为7．0，最佳振荡频率为200r/min，装液量为30／250mL，并进行了中试罐发酵分析，测定了罐发酵过程中的菌量、pH、还原糖及总氮的变化情况。