Effects of fengycin from Bacillus subtilis fmbJ on apoptosis and necrosis in Rhizopus stolonifer

Abstract

The lipopeptide antibiotic fengycin, produced by Bacillus subtilis, strongly inhibits growth of filamentous fungi. In this study, we evaluated the effects of fengycin treatment on apoptosis and necrosis in Rhizopus stolonifer by means of cell staining and epifluorescence microscopy. At fengycin concentrations less than 50 μg/ml, treated fungal cells demonstrated a dose-dependent increase in apoptosis-associated markers compared with the untreated control. These markers included chromatin condensation, reactive oxygen species accumulation, mitochondrial membrane potential depolarization, phosphatidylserine externalization, and the occurrence of DNA strand breaks. These results showed that fungal cells were impaired in a number of important functions and entered apoptosis upon treatment with low concentrations of fengycin. In contrast, high concentrations (>50 μg/ml) induced necrosis, indicating that the fungicidal action of fengycin operates via two modes: apoptosis at low concentrations and necrosis at high concentrations. Additionally, the apoptotic effect that we have shown suggests that lower concentrations of fengycin than previously thought may be effective for food preservation.

Fengycins, Cyclic Lipopeptides from Marine Bacillus subtilis Strains, Kill the Plant-Pathogenic Fungus Magnaporthe grisea by Inducing Reactive Oxygen Species Production and Chromatin Condensation

“…When stained with DNA-binding nuclear dyes, the compacted chromatin appears brighter than the chromatin in nonapoptotic cells and the condensed nuclei can be easily identified by fluorescence microscopy (10). To explore the effects of fengycin BS155 on the chromatin of M.…”

“…Nuclear chromatin condensation, along with concomitant DNA fragmentation, is one of the most important criteria used to identify apoptotic cells (10). Consistently, in the differentially expressed proteins quantified by our above-mentioned proteomic analysis, a total of 93 nucleus-associated proteins were identified, 16 of which were significantly altered at the level of their expression.…”

“…Among these CLPs, fengycins exhibit powerful antifungal activity against a wide range of phytopathogens (9). Fengycin homologues effectively inhibit the growth of filamentous fungi, such as Rhizopus stolonifer, Gibberella zeae, Aspergillus niger, Mucor rouxii, Fusarium graminearum, and Sclerotinia sclerotiorum (10–13). Fengycin and the closely related plipastatin CLPs are composed of an N-terminal β-hydroxy fatty acid chain attached to a decapeptide forming a cyclic lactone ring.…”

“…Reactive oxygen species (ROS) can oxidize lipids, proteins, DNA, and carbohydrates within biological organisms, leading to the breakdown of the cellular membrane or cell death (20). Recent research showed that CLPs, including bacillomycin D, iturins, and fengycins, were involved in an antagonistic interaction with the plant fungal pathogens by inducing ROS production (10, 21, 22). Additionally, certain CLPs specifically affect the signaling pathways of fungal or cancer cells.…”

Lipopeptide-Induced Suicidal Erythrocyte Death Correlates with the Degree of Acylation

“…Daptomycin shows high antibacterial activity in the presence of Ca 2+ ; the mode of action is still unknown but it induces permeabilization and depolarization of the bacterial cell membrane [92]. Iturin [93] and fengycin [94] strongly inhibit growth of filamentous fungi; the mode of action of fengycin is dose dependent: at low dose it induces apoptosis and at high dose necrosis [95]. …”