[The functional role of reduced inorganic sulfur compounds in the metabolism of the microaerophilic bacterium Spirillum winogradskii].
Oxidation of reduced sulfur compounds by microaerophilic sulfur bacterium Spirillum winogradskii was found to occur only concomitantly with consumption of an organic substrate and was not linked to their utilization as electron donors in energy metabolism. No enzymes of dissimilatory sulfur metabolism were found in the cells of the sulfur bacterium oxidizing thiosulfate to tetrathionate; oxidation of thiosulfate and sulfide was caused by their reaction with reactive oxygen species (ROS), mostly H2O2 produced in the course of aerobic growth. Decreased lytic effect of ROS in the presence of thiosulfate resulted in a twofold increase in the cell yield under aerobic conditions and more efficient substrate utilization. The latter effect was caused by decreased expense of energy for the biosynthesis of oxygen-protecting polysaccharides. The stimulatory effect of thiosulfate on the growth processes was due to the activation of a number of TCA cycle enzymes producing the intermediates for constructive metabolism, especially of the NADP-dependent malic enzyme. As a result of thiosulfate-induced synthesis of SH-containing cell components, the integral antioxidative activity increased 1.5-fold.
Podkopaeva
D A
DA
Grabovich
M Iu
MIu
Dubinina
G A
GA
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D006861:Hydrogen Peroxide / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013139:Spirillum / Q000254:growth & development / Q000378:metabolism*; D013457:Sulfur Compounds / Q000378:metabolism*; D013885:Thiosulfates / Q000378:metabolism
D017382:Reactive Oxygen Species; D013457:Sulfur Compounds; D013885:Thiosulfates; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D008291:Malate Dehydrogenase; D010100:Oxygen