Characterization of an extracellular enzyme system produced by Micromonospora chalcea with lytic activity on yeast cells

Abstract

Growth of Micromonospora chalcea on a de®ned medium containing laminarin as the sole carbon source induced the production of an extracellular enzyme system capable of lysing cells of various yeast species. Production of the lytic enzyme system was repressed by glucose. Incubation of sensitive cells with the active component enzymes of the lytic system produced protoplasts in high yield. Analysis of the enzyme composition indicated that b(1R3) glucanase and protease were the most prominent hydrolytic activities present in the culture¯uids. The system also displayed weak chitinase and b(1R6) glucanase activities whilst devoid of mannanase activity. Our observations suggest that the glucan supporting the cell wall framework of susceptible yeast cells is not directly accessible to the puri®ed endo-b(1R3) glucanase and that external proteinaceous components prevent breakdown of this polymer in whole cells. We propose that protease acts in synergy with b(1R3) glucanase and that the primary action of the former on surface components allows subsequent solubilization of inner glucan leading to lysis.

β-1,3-Glucanase from Delftia tsuruhatensis Strain MV01 and Its Potential Application in Vinification

“…Degradation of polymers such as glycogen, pullulan (from Aureobasidium pullulans), mannan (from Saccharomyces cerevisiae), pustulan, and dextran was analyzed by cultivation of the bacterial strain with 5 g/liter of each polymer in medium MM (see below). Then the respective culture supernatant was incubated with 1 g/liter of the corresponding polymer for 24 h, and the cleaving fragments produced were identified by thin-layer chromatography (26). Solid medium MM was supplemented with 1 g/liter of laminarin (from Laminaria digitata), xylan from oat spelt, starch, casein, or azure chitin, respectively.…”

“…The test was carried out in microtiter plates according to a modified description by Gacto et al (26). Cells were suspended in 10 mM sodium citrate buffer, pH 4.0, up to an optical density of approximately 1.0.…”

Actinobacteria Isolation from Metal Contaminated Soils for Assessment of their Metal Resistance and Plant Growth Promoting (PGP) Characteristics

“…These included, Nocardiopsis dassonvillei which exhibits mycolytic and parasitic activities against the vegetative hyphae of Fusarium oxysporum, and Micromonospora globosa which parasitize Fusarium udum through coiling, penetration and branching leading to granulation, coagulation of the cytoplasm and hyphal lysis. The importance of cell wall degrading enzymes produced by non-streptomyces actinomycetes has also been shown, such as that of chitinase and β-1,6 glucosidase (Gacto et al, 2000;Nawani et al, 2002). Micromonospora carbonacea, high producer of chitinase has been shown to suppress the pathogen of lettuce Sclerotinia minor.…”

Enzymic Activity of the K5-Type Yeast Killer Toxin and Its Characterization

“…-1,3-glucan is the major cell-wall component of most fungi which is responsible for the rigidity of the cell envelope. 21) This structure is hydrolyzed either by exo or endo -1,3-glucanases, and thus -1,3-glucanases are considered to be potential biocontrol agents in agriculture and antimicrobial agents in medicine and have received attention also due to their increasing importance in the modification of -glucans for pharmaceutical purposes. 22) Broad antifungal spectrum and reasonable pH and thermo stability (at pHs 3-5.5 and temperatures up to 37 C) of the K5-type yeast killer toxin highlighted its potential use in science and biotechnology.…”