ABSTRACT
Effect of various fermentation media, carbon sources, nitrogen sources, phosphate concentration and culture requirements includes inoculum levels and age were determined on gentamicin production and biomass dry weight production for Micromonospora echinospora, a gentamicin producing strain. Of the substrates tested, starch as a sole carbon source promoted maximal gentamicin production, while maltose promoted maximal growth. Yeast extract as a sole nitrogen source promoted maximal growth, while soyabean meal for gentamicin production. Increasing phosphate concentration enhanced gentamicin production and observed optimum production at 1.2 g/1 (6% v/v) of phosphate having 72 h old inoculum in the medium. Highest gentamicin production was obtained after cultivation with shaking for 120 h in a medium containing starch 0.75% (w/v), soyabean meal 0.5%, K2HPO4 0.12%, CaCO3 0.4%, FeSO4 0.003% and CoCl2 0.0001%. The gentamicin production was 1.2-fold in this medium as compared to basal medium.
Subject(s)
Anti-Bacterial Agents/biosynthesis , Culture Media/chemistry , Fermentation , Gentamicins/biosynthesis , Kinetics , Micromonospora/growth & developmentABSTRACT
A new sisomicin resistance gene sisR was cloned from sisomicin-producing Micromonospora inyoensis. The sisR fragment was obtained by PCR amplification. The primer pairs were designed based on grm gene sequence from gentamicin-producing Micromonospora purpurea. The template DNA was isolated from Micromonospora inyoensis. A series of different DNA fragments were amplified by PCR, which were sub-cloned to vector pUC19 for further identification. It was found that five specific transformants containing target DNA fragments could resist high concentrations of sisomicin (over 1000 microg/mL sisomicin). One of them designated as sisR, was then sequenced and the alignment among sisR and other related genes showed that sisR gene differs from any known genes. It was concluded that sisR gene is a sequence that has not been reported so far.
Subject(s)
Anti-Bacterial Agents , Pharmacology , Bacterial Proteins , Genetics , Base Sequence , Cloning, Molecular , Drug Resistance, Microbial , Genetics , Genes, Bacterial , Micromonospora , Genetics , Molecular Sequence Data , Sisomicin , PharmacologyABSTRACT
De aguas del Río Reconquista se han podido aislar cepas de Micromonospora resistentes a altos niveles de cromo y otros metales pesados, capaces de crecer sobre ácido naftalén-2-sulfónico como única fuente de carbono. Este fenotipo es muy estable, lo que hace a este microrganismo interesante desde el punto de vista de la eliminación de residuos industriales que contengan este tipo de sustancias. La biodegradación procede mediante la formación de ácido salicílico y ácido gentísico como intermediarios, metabolitos que han sido aislados mediante cromatografía gaseosa y caracterizados mediante espectroscopía de masa