Characterization of spore germination of a thermoacidophilic spore-forming bacterium, Alicyclobacillus acidoterrestris.

The germination behaviors of spores of Alicyclobacillus acidoterrestris, which has been considered to be a causative microorganism of flat sour type spoilage in acidic beverages, were investigated. The spores of A. acidoterrestris showed efficient germination and outgrowth after heat activation (80 degrees C, 20 min) in Potato dextrose medium (pH 4.0). Further, the spores treated with heat activation germinated in McIlvaine buffer (pH 4.0) in the presence of a germinative substance (L-alanine) and commercial fruit juices, although not in phosphate buffer (pH 7.0). Heat activation was necessary for germination. The spores of A. acidoterrestris, which easily survived the heat treatment in acidic conditions, lost their resistance to heat during germination. Our results suggest that the models obtained from spore germination of A. acidoterrestris might be beneficial to determine adequate thermal process in preventing the growth of potential spoilage bacteria in acidic beverages.

FR177391, a new anti-hyperlipidemic agent from Serratia. I. Taxonomy, fermentation, isolation, physico-chemical properties, structure elucidation and biological activities.

In the course of screening for a new anti-hyperlipidemic agent from microbial products, we found that FR177391, produced by Serratia liquefaciens No. 1821, alleviated the decrease in lipid droplet formation in differentiated 3T3-L1 adipocyte cells, induced by the addition of tumor necrosis factor-alpha. Structural elucidation by spectroscopic methods and X-ray crystallographic analysis of its propylamide derivative revealed that FR177391 was a chlorinated macrocyclic lactone.

FR182876, a new microtubule modulator with high water-solubility, from a Streptomyces.

In the course of seeking new anti-tumor drugs, a new microtubule modulator with high water-solubility, FR182876, was isolated from a Streptomyces which also produces FR182877. Even modern spectroscopic methods could not solve the structure of FR182876 due to its structural complexity and chemical instability. Thus, we have combined chemical correlations with spectroscopic methods and determined its structure, which features a highly fused ring system and 3-methylhistidine. The latter is believed to contribute to both solubility in water and activity in promoting tubulin polymerization. FR182876 showed potent cytotoxicity against a panel of cancer cells at concentrations of 28-75 ng/ml.

Siderophore production and induction of iron-regulated proteins by a microorganism from rhizosphere of barley.

This study provides new information on the Fe uptake system capable of supporting growth of the organism. Pseudomonas fluorescens isolated from the rhizosphere of barley, a gramineous plant, produced a siderophore under iron-limiting conditions. Its chemical structure was identified as pyochelin, on the basis of 1H and 13C NMR data of a stable methyl ester derivative. The same iron-limiting conditions induced a new set of outer membrane proteins (75 and 55 kDa), consistent with a siderophore-mediated iron-uptake system.