Metabolic products of microorganisms. Stereochemistry of lankamycin

The stereochemical structure of the macrolide antibiotic lankamycin could be completed by an extended NMR.-analysis of the degradation products III, IV, VI and VIII.     

Metabolic products of microorganisms. Structure of cinerubine B

The structural determination of the anthracycline antibiotic Cinerubine B by degradation, spectroscopic studies and an X-ray crystallographic analysis of a degradation product is described.     

Metabolic products of microorganisms. Concerning the constitution of borrelidin

By means of chemical degradation, N.M.R. and mass spectrometry structure II has been determined for the antibiotic borrelidin.     

229. Metabolic products of microorganisms. 102. The structure of venturicidin A and B

Chemical degradations and spectroscopic investigations of the macrolide antibiotics venturicidin A and B are described. In combination with an X-ray crystallographic analysis they lead to complete structures.     

Metabolic products of microorganisms. 108. Crystal structure analysis of chlorothricolide methyl ester

The X-ray crystal structure analysis of the Caesium salt of Chlorothricolide methylester, derived from the aglycone of the antibiotic chlorothricin, is described.     

Metabolic products of microorganisms. An unexpected rearrangement in the chlorothricin series]

The O-methyl derivative II of chlorothricin aglycone is rearranged by alcoholic sodium hydroxide to the dihydronaphthaline III. The structure of the product is proven by spectroscopic investigations, dehydrogenation to the naphthaline derivatives VI and VIII, and by a spectroscopic comparison (UV., ¹H- and ¹³C-NMR.) with the synthetic analogues XXVII and XXVIII resp. The synthesis of the latter two compounds is described.     

Metabolic products of microorganisms. 107. Structure of the chlorothricins, a new macrolide antibiotic

Chemical and spectroscopic evidence for the structural formula 9 of chlorothricolide methyl ester, derived from the aglycone of the antibiotic chlorothricin, is given. By chemical degradation and spectroscopic investigations structure 41 is deduced for the intact antibiotic.     

Metabolic engineering of microorganisms for isoprenoid production

Isoprenoids are ubiquitous in nature and range from essential cell components to unique secondary metabolites. The two isoprenoid biosynthetic pathways have received much attention from a metabolic engineering standpoint, and significant advances have been made in increasing flux through these pathways. Engineering later steps in isoprenoid biosynthetic pathways, specifically those related to the functionalization of terpene backbones, is at an earlier stage of development, both in terms of gene discovery and heterologous expression. Here we review recent advances in the metabolic engineering of microbes for isoprenoid production as well as some novel approaches to gene discovery and expression.     

采油微生物的代谢过程

微生物采油可提高原油采收率,我国油藏及储集层类型多,原油性质变化大,微生物驱油机理研究非常重要[1,2]。本文对大港油田官69断块分离筛选的以烃类为唯一碳源的采油微生物菌组B05,通过室内试验,对其代谢过程的研究结果表明:BO5能不同程度地对原油进行降解,并代谢产生有机酸、生物表面活性剂和生物气等主要产物,它们通过与原油/岩石/水界面的相互作用,改善地下原油的流动性质,提高原油采收率。1　实验部分1 1　实验材料及仪器菌组筛选自大港油田官69断块(菌号B05),芽孢杆菌属(Bacillus),革兰氏染色G+,嗜热、兼性厌氧,最适生长温度73…     

The influence of products and by-products obtained by drinking water electrolysis on microorganisms

It is the aim of this work to underline the chemical character of disinfection processes and to present the results of treatment experiments for artificially and electrochemically added chemicals focusing on chlorine components and hydrogen peroxide obtained on IrO₂/RuO₂ anodes. A discontinuous cell with rotating anode placed 4 mm above an IrO₂ expanded mesh cathode of same diameter was used for the generation of electrolysis products. The thermostated experiments were carried out at a temperature of 20 °C and in constant current mode. Artificial solutions prepared using sodium salts and deionised water were electrolysed. Samples were analysed using the DPD (N, N-diethyl-p-phenylendiamine) method. Escherichia coli K-12, Bacillus subtilis DSM 2277 and Saccharomyces cerevisiae Kolin were used as test-microorganisms. Morphological changes were studied using transmission electron microscopy. The results show that electrolysed water had a higher lethal efficiency than Ca(OCl)₂ of the same measured active chlorine concentration. During the killing period mainly inner cell parts of the microorganisms react chemically with the disinfectants. In sufficiently high concentrations and reaction times, the cell material continues to react. Cell walls or membranes can break-through as electron microscopy pictures show. Electrolysed water had a higher lethal efficiency on microorganisms. This behaviour demonstrates the existence of additional by-products.     

Metabolites of microorganisms. Aranciamycin

Aranciamycin is a new antibiotic isolated from cultures of a strain of Streptomyces echinatus. The orange-yellow acidic compound, C₂₇H₂₈O₁₂, is a glycoside of an aglycone, aranciamycinone, and a 6-deoxyhexose monomethyl ether. The aglycone, C₂₀H₁₆O₈, is composed of a 1, 8-dihydroxyanthraquinone nucleus, to which a fourth carbocyclic six-membered ring is condensed, bearing a tertiary C-methyl group, a tertiary and a secondary hydroxyl group, a secondary methoxyl group, and a carbonyl group. A partial formula of the aglycone is given. Aranciamycin as well as its aglycone are strongly inhibitory against gram-positive bacteria on synthetic media. The antibiotic activity is considerably decreased by the addition of amino-acid combinations and pyruvate to the test medium.