Antibiosis and dark-pigments secretion by the phytopathogenic and environmental fungal species after interaction in vitro with a Bacillus subtilis isolate

Abstract

In this work, different reactions in vitro between

Phyllosphere Fungal Communities of Plum and Antifungal Activity of Indigenous Phenazine-Producing Pseudomonas synxantha Against Monilinia laxa

“…Since no contacts between the bacterial and fungal colonies were established, melanization of the cell wall was presumably caused by a diffusible and soluble bacterial product other than that extracted by benzene. Similar results, with either diffusion of melanin on agar plates and/or melanization of fungal cells, were obtained by several authors: Machado et al (2010a, b) in co-cultures of Aspergillus niger , A. alternata and Fonsecaea pedrosoi with Bacillus subtilis ; and Frases et al (2007) after co-culturing Cryptococcus neoformans with Klebsiella aerogenes. The observed melanization of the M. laxa hyphal cell wall is a typical stress response to adverse environmental conditions, known to be induced by several factors: microbial antagonism (as a way to increase antifungal resistance), host defense mechanisms, predation by amoebae, extreme temperatures, UV radiation, hydrolytic enzymes, oxidative radicals, metal toxicity (Fogarty and Tobin, 1996; Henson et al, 1999; Nosanchuk and Casadevall, 2003).…”

Bacillus subtilis induces morphological changes in Fonsecaea pedrosoi in vitro resulting in more resistant fungal forms in vivo

“…Nonetheless, chlamydoconidia-shaped cells have been shown to be worthy of future studies on the development of experimental infections, in which B. subtilis or other antagonistic strains can be used in co-cultures with CBM agents, especially because these forms may be precursors of sclerotic bodies. Recently, we developed a murine chronic infection after inoculation of round cells and chlamydoconidia from F. pedrosoi cells cultivated for long periods (23).…”

“…An environmental bacillus isolated from random soil samples collected from the campus of the Federal University of Mato Grosso (Cuiabá, Mato Grosso state, Brazil) was used in this study; as in previous co-culture assays, it was able to inhibit the growth of some phytopathogenic fungi and to induce the release of dark pigment by dematiaceous molds. This bacterium was identified as B. subtilis by classical and molecular methods (23).…”

“…In a preliminary study, we isolated an environmental gram-positive bacterium from Brazilian soil that antagonizes several fungi, including some dematiaceous species (23). Herein, we studied the interactions between this bacterium and a clinical strain of F. pedrosoi in two manners: firstly, we examined the in vitro changes in fungal cells after co-culturing with bacillus, and secondly, we explored the in vivo significance of this interaction.…”

Production, Characterization, and Antimicrobial Activity of Mycocin Produced byDebaryomyces hanseniiDSMZ70238

“…Wells in the size of 5 mm were cut by using sterile cork borer, and up to 100  µ l of concentrated killer toxin extract was added to each well. The plates were incubated at 37°C for 24–48 h and the diameter of the clear zone around the wells was measured [22]. The assay was repeated three times from three independent biological replicates.…”