Characterization of dioxygenases and biosurfactants produced by crude oil degrading soil bacteria

ABSTRACT Role of microbes in bioremediation of oil spills has become inevitable owing to their eco friendly nature. This study focused on the isolation and characterization of bacterial strains with superior oil degrading potential from crude-oil contaminated soil. Three such bacterial strains were selected and subsequently identified by 16S rRNA gene sequence analysis as Corynebacterium aurimucosum, Acinetobacter baumannii and Microbacterium hydrocarbonoxydans respectively. The specific activity of catechol 1,2 dioxygenase (C12O) and catechol 2,3 dioxygenase (C23O) was determined in these three strains wherein the activity of C12O was more than that of C23O. Among the three strains, Microbacterium hydrocarbonoxydans exhibited superior crude oil degrading ability as evidenced by its superior growth rate in crude oil enriched medium and enhanced activity of dioxygenases. Also degradation of total petroleum hydrocarbon (TPH) in crude oil was higher with Microbacterium hydrocarbonoxydans. The three strains also produced biosurfactants of glycolipid nature as indicated d by biochemical, FTIR and GCMS analysis. These findings emphasize that such bacterial strains with superior oil degrading capacity may find their potential application in bioremediation of oil spills and conservation of marine and soil ecosystem.

First detection of Corynebacterium ulcerans producing a diphtheria-like toxin in a case of human with pulmonary infection in the Rio de Janeiro metropolitan area, Brazil

The frequency and severity of human infections associated with Corynebacterium ulcerans appear to be increasing in different countries. Here, we describe the first C. ulcerans strain producing a diphtheria-like toxin isolated from an elderly woman with a fatal pulmonary infection and a history of leg skin ulcers in the Rio de Janeiro metropolitan area.

Flocculation of fine fluorite particles with corynebacterium xerosis

The treatment of fine particles dispersed in liquids is common in several industries and especially important in mineral processing. The efficiency of settling operations can be susbstantially increased by flocculation. The aim of this work was to study the flocculation of fine fluorite particles by the bacterium Corynebacterium xerosis. Flocculation tests, microelectrophoresis measurements and optical microscopy were used to evaluate flocculation. The results showed that C. xerosis cells adhere to the fluorite surfaces promoting the aggregation of the particles. High quality flocs can be obtained rapidly at ph 7.0 using a cell concentration of 40 mg/l, considerably lower than previously reported in the literature. The results are discussed with reference to the surface characteristics of the mineral and of the microorganism.

Produccion de l-lisina por celulas en no crecimiento de Corynebacterium glutamicum / L-lysine production by corynebacterium glutamicum non growing cells

Los efectos estrógenos y la progesterona en el control endocrino de las funciones sexuales son bien conocidos. Sin embargo, su papel en el control de áreas extrahipotalámicas ha sido poco estudiado. Trabajos previos realizados en nuestro laboratorio demuestran que el 17 Beta-Estradiol tiene un efecto inhibitorio en la transmisión cortico-caudado. En el presente trabajo se exploraron los efectos de la inyección intravenosa de 17 alpha-Hidroxi-Progesterona sobre esta misma conexión. Ratas hembras intactas, hembras ovariectomizadas y machos intactos, de la variedad Sprague Dawley, de 250 a 300 g de peso, fueron anestesiadas con Hidrato de Cloral (40 mg/100 g; i.p.). La hormona se administró a través de um catéter colocado en la vena yugular derecha (10 mul; 2,5 mg/ml). Se usaron métodos electrofisiológicos convencionales, utilizando electrodos de vidrio para el registro de las respuestas en el Caudado y electrodos metálicos para la estimulacióncortical, aislados excepto en la punta. Las respuestas excitatorias fueron analizadas por una computadora, integrando barridos sucessivos para construir histogramas post-estímulos. La administración de la 17 alpha-Hidroxi-Progesterona produjo un aumento significativo de las respustas en la mayoría de las células (95 por ciento). En algunas células (35 por ciento), este aumento fue acompañado de una disminución también significativa. En una sola neurona la respuesta excitatoria disminuyó. Los cambios descritos se observaron a partir de los primeros 5-10 minutos después de la administración hormonal, y se prolongan por una hora o más, luego de lo cual se observa recuperación de la respuesta inicial. Los resultados demuestran que la 17 alpha-Hidroxi-Progesterona estimula la transmisión cortico-caudado en la rata. La corta latencia de estos efectos hace suponer que pueden estar mediados por mecanismos no genómicos.