Antifungal antibiotic

About: Antifungal antibiotic is a research topic. Over the lifetime, 1450 publications have been published within this topic receiving 40316 citations.

Biological control of soil-borne pathogens by fluorescent pseudomonads

Abstract: Particular bacterial strains in certain natural environments prevent infectious diseases of plant roots. How these bacteria achieve this protection from pathogenic fungi has been analysed in detail in biocontrol strains of fluorescent pseudomonads. During root colonization, these bacteria produce antifungal antibiotics, elicit induced systemic resistance in the host plant or interfere specifically with fungal pathogenicity factors. Before engaging in these activities, biocontrol bacteria go through several regulatory processes at the transcriptional and post-transcriptional levels.

Rapamycin (ay-22, 989), a new antifungal antibiotic i. taxonomy of the producing streptomycete and isolation of the active principle

Abstract: A streptomycete was isolated from an Easter Island soil sample and found to inhibit Candida albicans, Microsporum gypseum and Trichophyton granulosum. The antibiotic-producing microorganism was characterized and identified as Streptomyces hygroscopicus. The antifungal principle was extracted with organic solvent from the mycelium, isolated in crystalline form and named rapamycin. Rapamycin is mainly active against Candida albicans; minimum inhibitory concentration against ten strains ranged from 0.02 to 0.2 mug/ml. Its apparent activity against Microsporum gypseum and Trichophyton granulosum is lower because of its instability in culture media on prolonged incubation required by these fungi. No activity was observed against gram-positive and gram-negative bacteria. Acute toxicity in mice is low.

Rapamycin (AY-22,989), a new antifungal antibiotic. II. Fermentation, isolation and characterization.

Abstract: Rapamycin is a new antifungal antibiotic produced by Streptomyces hygroscopicus NRRL 5491. It was isolated from the mycelium by solvent extraction, purified by silica gel column chromatography and crystallized as a colorless solid which melts at 183 approximately to 185 degrees C and has the empirical formula C56H89NO14. From its characteristic ultraviolet absorption spectrum rapamycin can be classified as a triene. It is highly active against various Candida species, especially Candida albicans. Its activity is compared with that of amphotericin B, candicidin and nystatin.

Regulation of antibiotic production in root-colonizing pseudomonas spp. and relevance for biological control of plant disease

Abstract: Certain strains of fluorescent pseudomonads are important biological components of agricultural soils that are suppressive to diseases caused by pathogenic fungi on crop plants. The biocontrol abilities of such strains depend essentially on aggressive root colonization, induction of systemic resistance in the plant, and the production of diffusible or volatile antifungal antibiotics. Evidence that these compounds are produced in situ is based on their chemical extraction from the rhizosphere and on the expression of antibiotic biosynthetic genes in the producer strains colonizing plant roots. Well-characterized antibiotics with biocontrol properties include phenazines, 2,4-diacetylphloroglucinol, pyoluteorin, pyrrolnitrin, lipopeptides, and hydrogen cyanide. In vitro, optimal production of these compounds occurs at high cell densities and during conditions of restricted growth, involving (i) a number of transcriptional regulators, which are mostly pathway-specific, and (ii) the GacS/GacA two-component system, which globally exerts a positive effect on the production of extracellular metabolites at a posttranscriptional level. Small untranslated RNAs have important roles in the GacS/GacA signal transduction pathway. One challenge in future biocontrol research involves development of new strategies to overcome the broad toxicity and lack of antifungal specificity displayed by most biocontrol antibiotics studied so far.

Rapamycin (AY-22,989), a new antifungal antibiotic. II. Fermentation, isolation and characterization.:II. FERMENTATION, ISOLATION AND CHARACTERIZATION

Abstract: : Rapamycin is a new antifungal antibiotic produced by Streptomyces hygroscopicus NRRL 5491. It was isolated from the mycelium by solvent extraction, purified by silica gel column chromatography and crystallized as a colorless solid which melts at 183 approximately to 185 degrees C and has the empirical formula C56H89NO14. From its characteristic ultraviolet absorption spectrum rapamycin can be classified as a triene. It is highly active against various Candida species, especially Candida albicans. Its activity is compared with that of amphotericin B, candicidin and nystatin.