Rhizocticin A, an antifungal phosphono-oligopeptide of Bacillus subtilis ATCC 6633: biological properties

Abstract

Rhizocticin A, the main component of the antifungal, hydrophilic phosphono-oligopeptides of Bacillus subtilis ATCC 6633, was used for sensitivity testing and experiments into the molecular mechanism of the antibiotic action. Budding and filamentous fungi as well as the cultivated nematode Caenorhabditis elegans were found to be sensitive, whereas bacteria and the protozoon Paramecium caudatum were insensitive. Rhizoctonia solani was inhibited in agar dilution tests but not in diffusion tests. The antifungal effect of rhizocticin A was neutralized by a variety of amino acids and oligopeptides. Oligopeptide influence was mainly understood as transport antagonism, and it was concluded that the antibiotic enters the recipient cell via the peptide transport system. L- and D-cystine were also identified as potent, general antagonists of the oligopeptide transport. The rhizocticin-antagonism of four other amino acids was taken as a clue to the site of action. Provided that rhizocticin A is split by peptidases of the target cell into inactive L-arginine and toxic L-2-amino-5-phosphono-3-cis-pentenoic acid (L-APPA), the latter may interfere with the threonine or threonine-related metabolism.

Production by Bacillus pumilus (MSH) of an antifungal compound that is active against Mucoraceae and Aspergillus species: preliminary report

“…In the search for anti-infectives produced by Bacillus species, especially Bacillus cereus, Bacillus subtilis and Bacillus licheniformis, several antifungal compounds, mainly peptides, have been described (Katz & Demain, 1977;Kugler et al, 1990;Lebbadi et al, 1994;Shosi, 1978;Silo-Suh et al, 1994). While investigating the microbial flora of a dry, used, synthetic sponge by touch inoculation to 5 % sheep-blood agar, the concomitant growth of Bacillus pumilus and a Mucor species occurred after 24 h incubation.…”

Antimicrobial Activity of Bacillus Sp. Jg: Isolation, Identification and Process Optimization for the Production of Antimicrobial Metabolite Against Human Pathogens

“…[21] In the search for antibiotics produced by Bacillus species, especially Bacillus cereus, Bacillus subtilis and Bacillus licheniformis, several antifungal compounds, mainly peptides, have also been described. [22,23,24,25] Bottone & Peluso [26] have reported a compound produced by Bacillus pumilus (MSH) that inhibits…”

Antibacterial peptides from thermophilic bacteria

“…Rhizocticin A is l-arginyl-l-2-amino-5-phosphono-3-cis-pentenoic acid (Arg-APPA); rhizocticin B is-valyl l-arginyl-l-2-amino-5-phosphono-3-cis-pentenoic acid (Val-Arg-APPA); and rhizocticin C and D are the same as rhizocticin B but Val is substituted with l-isoleucine (Ile) and l-leucine (Leu), respectively. Rhizocticins enter the target fungal cell through the oligopeptide transport system (Kugler et al, 1990) and then are cleaved by host peptidases to release(Z)-l -2-amino-5-phosphono-3-panteonic acid (APPA), which inhibits threonine synthase, catalyzing the pyridoxal 5′-phosphate (PLP)-dependent conversion of phosphohomoserine to l-threonine (Laber et al, 1994). APPA interferes with the biosynthesis of threonine and related metabolic pathways, initially affecting protein synthesis and leading to growth inhibition.…”