Involvement of β-Glucans in the Wide-Spectrum Antimicrobial Activity of Williopsis saturnus var. mrakii MUCL 41968 Killer Toxin

Abstract

Background: Williopsis saturnus var. mrakii MUCL 41968 secretes a 85-kDa glycoprotein killer toxin (WmKT) that displays a cytocidal activity against a wide range of microorganisms, making WmKT a promising candidate for the development of new antimicrobial molecules. Although the killing mechanism of WmKT is still unknown, the toxin was recently proposed to bind to the surface of sensitive microorganisms through the recognition of ␤-glucans. Indeed, Saccharomyces cerevisiae strains sensitive to the toxin become resistant when mutated in their ␤-glucan synthesis pathway. Materials and Methods: To investigate the interaction of WmKT with ␤-glucans, we examined in agar diffusion assays the WmKT activity in the presence of enzymes displaying ␤-glucanase activity. The toxin activity was also investigated using spheroplasts derived from sensitive yeast cells. The hydrolytic activity of WmKT was studied using specific glucosidase inhibitors as well as various sugar molecules covalently linked to p-nitrophenyl as potential substrates. Finally, the ultrastructural modifications induced by WmKT activity on sensitive yeasts were assessed by scanning electron microscopy.

Novel chitin/chitosan-glucan wound dressing: Isolation, characterization, antibacterial activity and wound healing properties

“…Similar phenomenon was also observed and reported elsewhere (Annur et al, 2015;Inamdar and Mourya, 2014;Li et al, 2013;Rodríguez-Núñez et al, 2012;Siralertmukul et al, 2015). Glucan in chitin/chitosanglucan complex had antibacterial activity against different types of bacteria and fungi (AL TUWAIJRI et al, 1987;Bohn and BeMiller, 1995;di Luzio et al, 1979;Guyard et al, 2002;Kagimura et al, 2015;Kokoshis et al, 1978;Luzio et al, 1980;Talbott and Talbott, 2009). The antibacterial activity of the nonwoven wound dressing was only dependent on the biological activity of chitin/chitosan but also the antibacterial activity of glucan.…”

Therapeutic Activity of an Engineered Synthetic Killer Antiidiotypic Antibody Fragment against Experimental Mucosal and Systemic Candidiasis

“…Thus, a KT-neutralizing monoclonal antibody (MAb) (mAbKT4) was used to raise antiidiotypic antibodies (IdAb) representing the internal image of the KT active domain (KTIdAb) and endowed with effective binding to KTR, KT-like microbicidal activity in vitro, and pronounced protective effects in vivo (23,(26)(27)(28). The KTR has recently been identified as a ␤-glucan (12,13), thus indirectly supporting the concept that KT-IdAb's could indeed recognize this cell wall polysaccharide and then exert their cytocidal action on a large variety of glucan-possessing pathogens (4).…”

“…For this, we were also encouraged by the recent identification of KTR as a ␤-glucan component of the cell wall (12). Importantly, glucan and glucan-like molecules are largely present in the microbial world, where they exert critical structural and/or virulence properties.…”

Monoclonal Immunoglobulin G1 Directed againstAspergillus fumigatusCell Wall Glycoprotein Protects against Experimental Murine Aspergillosis

“…Candidacidal antibodies against C. albicans have been reported, where the target was located in the cell wall of Candida (15,27,32). Recently a humanized MAb directed against heat shock protein (HSP90) has entered clinical trials for the treatment of candidiasis.…”