Tonic basal release of nitric oxide (NO) by vascular endothelial cells controls blood pressure (BP) in the basal state. In these studies we investigated the effects of chronic inhibition of basal NO synthesis in the rat for a 2-mo period. Significant systemic hypertension developed in chronically NO-blocked rats compared to controls. Marked renal vasoconstriction was also observed with elevations in glomerular blood pressure (PGC) and reductions in the glomerular capillary ultrafiltration coefficient (Kf). Chronically NO-blocked rats also develop proteinuria and glomerular sclerotic injury compared to controls. These studies therefore describe a new model of systemic hypertension with glomerular capillary hypertension and renal disease due to chronic blockade of endogenous NO synthesis. These observations highlight the importance of the endogenous NO system in control of normal vascular tone and suggest that hypertensive states may result from relative NO deficiency. (J. Clin. Invest. 1992. 90:278-281.) Key words: nitric oxide * hypertension glomerulus * single nephron glomerular filtration rate
Clostridium botulinum 62-A was shown to catabolize L-arginine via citrulline to ornithine, NH3, and CO2. The individual enzymes of the dihydrolase system were all demonstrated in extracts of cells, spores, and germinated spores. There was no liberation of urea from L-arginine, so no functional arginase enzyme is present, but there was some transamidinase activity in cell extracts. L-Ornithine was degraded at a significant rate by cells grown in an L-ornithine-supplemented medium; it was partially decarboxylated to putrescine and partially fermented to NH3, CO2, volatile acids, and 5-aminovaleric acid. Results from the fermentation of L-ornithine-C'4,-1-C'4, and-2-C14 demonstrated that essentially all of the CO2 was derived from carbon 1, and volatile acids from carbons 2 to 5. Assays for the products of L-ornithine-C14 fermentation revealed that the volatile acids consisted of acetate, propionate, valerate, and butyrate (in order of decreasing concentrations), and that 5-amino
Spores of Bacillus popilliae from infected larvae and refractile bodies produced in a Trypticase-barbiturate medium were similar but distinct from vegetative cells of this organism in protein, nucleic acid, and enzyme composition. The spores and refractile bodies were found to have catalase activity, some of which was heat-resistant. This enzyme was not found in the vegetative cells. The spores contained dipicolinic acid, but the refractile bodies did not. The latter were similar to cells in having considerably higher levels of phosphate extractable with cold trichloroacetic acid and of poly-f-hydroxybutyrate than had the spores. Electron microscopy demonstrated conclusively that the refractile bodies are distinctly different from either cells or spores of B. popilliae. The possibility that these bodies are formed as a result of an aborted sporulation process is discussed. Practically every cell of Bacillus popilliae produces a spore during production of "milky disease" in Japanese beetle larvae. In contrast, the best efforts published to date have resulted in a maximum of about 0.3%7o sporulation in vitro (30) on a solid medium. More recently, a strain has been isolated (NRRL B-2309M) in which about 15 % sporulation has been observed on a solid medium (E. S. Sharpe and G. St. Julian, Bacteriol. Proc., 1967, p. 10). For several years we have sought to ascertain any unique characters which might provide a key to sporulation of B. popilliae. This organism is a strict aerobe (24); glucose is catabolized by both the glycolytic and hexosemonophosphate pathways, producing acetate, lactate, and C02 primarily (4); acetate is not oxidized to a significant extent except by a single mutant strain (4); the electron transport system is deficient in cytochrome c (5); stationary-phase cultures generate considerable hydrogen peroxide and lack the ability to degrade it (5); cells are quite sensitive to 0.01 M H202 (8); the organism is auxotrophic for 11 amino acids and for thiamine (36); and barbituric acid is required for consistent growth in a synthetic medium (36). During these studies, a medium was developed 1 Published with the approval of the Director of the Michigan Agricultural Experiment Station as Journal Article 4058.
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