Myxothiazol, an antibiotic from myxococcus fulvus. (myxobacterales) I. cultivation, isolation, physico-chemical and biological properties.

Abstract

Fermentations were performed in 70-liter fermentors (Giovanola, Manthey, Switzerland) equipped with a circulating pump stirrer system ("intensor system"). Antifoam Lb 625 (Brenntag, Miilheim/ Ruhr) was added to the medium in a concentration of 0.03 %. To start the culture, 63 liters of medium were inoculated with 7 liters of shake culture broth in mid-log phase. The fermentor was maintained at 30°C, and stirred at 500 r.p.m. The aeration rate was 0.1 v/vm for the first 13 hours, and 0.17 v/vm for the following 17 hours. The pH was held constant at 7.5 with acetic acid. Within 8 hours after

Bio-Efficacy and Phyto-Toxicty of Azoxystrobin 23% SC against Powdery Mildew (Oidium mangiferae) and Anthracnose (Colletotrichum loeosporioides) Diseases in Mango

“…The PDI on inflorescence was also found minimum in Azoxystrobin 23% SC @ 2ml/L followed by Azoxystrobin @ 1ml/L (Table 3). This is mainly because azoxystrobins belong to the strobilurins group, are the leading systemic fungicide, found to exert their fungicidal action by blocking electron transport in the mitochondrial respiratory chain in fungi (Gerth et al, 1980). Significantly lower (16.64) PDI on fruits were recorded in Azoxystrobin @ 2ml/L and were maximum (50.10) in control (Table 4).…”

Concise Syntheses of Cystothiazoles A, C, D, and Melithiazol B

“…1) Furthermore, when 2 was examined for in vitro cytotoxicity using human colon carcinoma HCT-116 and human leukemia K562 cells, the resulting IC 50 values were 110-130 ng/ml, which were significantly higher than those of myxothiazol A. [4][5][6] The fungicidal activity of these bmethoxyacrylate (MOA) inhibitors has been shown to be due to their ability to inhibit mitochondrial respiration by blocking electron transfer between cytochrome b and cytochrome c. 7) The absolute structure of 2 was established by a combination of spectroscopic analysis and chemical degradation of the natural product.…”

“…1) Furthermore, when 2 was examined for in vitro cytotoxicity using human colon carcinoma HCT-116 and human leukemia K562 cells, the resulting IC 50 values were 110-130 ng/ml, which were significantly higher than those of myxothiazol A. [4][5][6] The fungicidal activity of these bmethoxyacrylate (MOA) inhibitors has been shown to be due to their ability to inhibit mitochondrial respiration by blocking electron transfer between cytochrome b and cytochrome c.7) The absolute structure of 2 was established by a combination of spectroscopic analysis and chemical degradation of the natural product.1) The left-side structure of 2 has been reported to be responsible for its antifungal activity. 8) For the purpose of studying the structure-biological activity relationships of cystothiazole A congeners, efficient synthesis of the left-side aldehyde 5a is considered to be highly important.…”

Two New Ring-Contracted Congeners of Rhizopodin Illustrate Significance of the Ring Moiety of Macrolide Toxins on the Actin Disassembly-Mediated Cytotoxicity

“…15,16) As part of our program to discover new bioactive metabolites from underexploited bacterial resources, we have collected myxobacteria from hotspring environments and screened their fermentation products for cytotoxicity and antimicrobial activity. While most of the cytotoxic extracts contained myxothiazole A 17,18) and exhibited broad antimycotic activity, three were found to selectively inhibit the growth of Saccharomyces cerevisiae. Intrigued by this unique activity, one of the hit strains coded YA1-5B-2, identified as Myxococcus stipitatus based on 16S ribosomal DNA (rDNA) sequence analysis, was chosen for further study.…”