Cloning,sequencing and analysis of the yeastS. uvarum ERG10 gene encoding acetoacetyl CoA thiolase

Summary TheERG10 gene specific toS. uvarum, a brewing yeast, has been cloned by complementation of anS. cerevisiae erg10 mutant.S. uvarum contains two differentERG10 genes. One of these is similar to theS. cerevisiae ERG10 gene; they are structurally different, but functionally homologous. The clonedERG10 gene has been located on chromosome XVI, and we have shown that it is allelic to the previously isolatedtsm0115 mutants. Northern blot and sequence analysis indicate that theERG10 gene is highly expressed, and biochemical and genetic evidence show that it encodes the cytoplasmic acetoacetyl CoA thiolase.     

Biosynthesis of two stage-specific membrane proteins during transformation of Plasmodium gallinaceum zygotes into ookinetes

We have studied the synthesis and expression of surface proteins in zygotes of Plasmodium gallinaceum during their transformation to mature ookinetes. The cells were biosynthetically labelled in vitro using [35S]methionine and proteins were immunoprecipitated with rabbit anti-ookinete serum or monoclonal antibodies. Early zygotes (approx. 2 h post-gametogenesis and fertilization) synthesized and expressed on their surface a protein of Mr 26 000 as observed under reducing conditions on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) (31 000 under non-reducing conditions) and continued to do so for 8-10 h; thereafter synthesis of the Mr 26 000 protein declined and little or none was synthesized in the mature ookinetes (greater than 20 h post-gametogenesis). Between 3-5 h post-gametogenesis, zygotes also began to synthesize a protein of Mr 28 000 (34 000 under non-reducing conditions). Synthesis and expression of this surface protein continued throughout development; and the Mr 28 000 protein was the predominant surface protein synthesized by the mature ookinete. Mr 26 000 and Mr 28 000 proteins have been designated earlier as PgO-1 and PgO-2 respectively (Carter and Kaushal, Mol. Biochem. Parasitol. (1984) 13, 235-241). Neither protein was synthesized in the gametocytes prior to gametogenesis. Both proteins could be labelled with [3H]glucosamine or [3H]mannose. When zygotes were incubated with [3H]palmitic acid both PgO-1 and PgO-2 bound fatty acids in covalent linkage. The two proteins do not otherwise appear to be structurally related. They were differentially immunoprecipitated by different monoclonal antibodies and gave rise to distinct patterns of peptides following digestion with proteases such as Staphylococcus aureus V-8, trypsin and chymotrypsin.     

3-苯基乳酸的研究进展

介绍了3-苯基乳酸的结构、制备、手性拆分等的研究现状，并阐述了其抑菌、药理作用及在医药、化工等领域的应用。     

Heparan sulphate,its derivatives and analogues share structural characteristics that can be exploited,particularly in inhibiting microbial attachment

Heparan sulphate (HS) and the related polysaccharide, heparin, exhibit conformational and charge arrangement properties, which provide a degree of redundancy allowing several seemingly distinct sequences to exhibit the same activity. This can also be mimicked by other sulphated polysaccharides, both in overall effect and in the details of interactions and structural consequences of interactions with proteins. Together, these provide a source of active compounds suitable for further development as potential drugs. These polysaccharides also possess considerable size, which bestows upon them an additional useful property: the capability of disrupting processes comprising many individual interactions, such as those characterising the attachment of microbial pathogens to host cells. The range of involvement of HS in microbial attachment is reviewed and examples, which include viral, bacterial and parasitic infections and which, in many cases, are now being investigated as potential targets for intervention, are identified.     

Nano in nano: Biosynthesized gold and iron nanoclusters cargo neoplastic exosomes for cancer status biomarking

Timely detection is crucial for successful treatment of cancer. The current study describes a new approach that involves utilization of the tumor cell environment for bioimaging with in-situ biosynthesized nanoscale gold and iron probes and subsequent dissemination of Au-Fe nanoclusters from cargo exosomes within the circulatory system. We have isolated the Au-Fe cargo exosomes from the blood of the treated murine models after in situ biosyntheses from their respective pre-ionic solutions (HAuCl₄, FeCl₂), whereas Na₂SeO₃ supplementation added into Au lethal effect. The microarray data of various differentially expressed genes revealed the up-regulated tumor ablation and metal binding genes in SGC-7901 cell lines after treatment with Au-Fe-Se triplet ionic solution. The isolation of Au-Fe nanoclusters cargo exosomes (nano in nano) after secretion from deeply seated tumors may help in early diagnosis and reveal the tumor ablation status during and after the relevant treatment like radio-chemo therapies et al.     

氨基糖苷类抗生素生物合成研究进展

作为曾经治疗细菌感染的一线临床药物,氨基糖苷类抗生素在人类与病源微生物的抗争中作出了不可磨灭的巨大贡献,也成就了这一类抗生素的辉煌。虽然,伴随着其耳毒性和肾毒性等毒副作用,以及日益严重的耐药性的严峻挑战,但借助现代科学技术的发展和认知水平的提高,氨基糖苷类抗生素许多不曾被了解的新的生物活性也正不断地丰富和拓展着它新的潜能,使之依然成为人类医药宝库中不可或缺的重要一员。基于此,本文从分子遗传学、生物化学及结构生物学角度对常见的天然和化学半合成氨基糖苷抗生素生物合成的研究进展进行简要的概述。     

Applications of biosynthesized metallic nanoparticles – A review

We present a comprehensive review of the applications of biosynthesized metallic nanoparticles (NPs). The biosynthesis of metallic NPs is the subject of a number of recent reviews, which focus on the various “bottom-up” biofabrication methods and characterization of the final products. Numerous applications exploit the advantages of biosynthesis over chemical or physical NP syntheses, including lower capital and operating expenses, reduced environmental impacts, and superior biocompatibility and stability of the NP products. The key applications reviewed here include biomedical applications, especially antimicrobial applications, but also imaging applications, catalytic applications such as reduction of environmental contaminants, and electrochemical applications including sensing. The discussion of each application is augmented with a critical review of the potential for continued development.     

金属离子对红霉素生物合成的影响

本文采用优化设计方法研究金属离子在红霉素生物合成中的交互作用，应用两水平因子设计和响应面设计，以最终发酵液的生物效价为目标函数建立模型，通过软件分析得出优化结果：钼酸钠0．0461g／100ml；硫酸锌0．004g／100ml；氯化锰0．0133g／100ml；硫酸镁0．0866g／100ml；氯化钙0．0293g／100ml。按优化方案向发酵液中添加所选定的金属盐，可使最终发酵液的生物效价由对照样品的6115u／ml，提高到条件样品的7985u／ml，在一定程度上实现了红霉素生产的优化。     

羊毛硫细菌素生物合成基因簇的遗传分析

羊毛硫细菌素是一类核糖体合成且经翻译后修饰的具有生物活性的小肽，通常含有羊毛硫氨酸及β-甲基羊毛硫氨酸等稀有氨基酸。近年来随着来源于乳酸乳球菌的nisin（乳链菌肽）被广泛地用作天然食品防腐剂和对其研究的不断深入，羊毛硫细菌素已引起研究者广泛关注。因其无耐药性，羊毛硫细菌素还极有可能替代传统抗生素应用于生物医药领域。羊毛硫细菌素的生物合成基因包括结构基因、修饰基因、加工基因、转运基因、免疫基因、调节基因，它们成簇排列于产生菌的染色体或质粒上，构成数个转录单元。本文综述了近年来羊毛硫细菌素生物合成基因簇遗传分析的研究进展。