The occurrence of killer characters in yeasts

Rosini, Gianfranco

doi:10.1139/m83-224

Cited by 48 publications

(32 citation statements)

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“…Since Bevan and Makower (3) discovered the killer phenomenon in strains of Saccharomyces cerevisiae, several other yeast species have been found to produce a toxic proteinaceous factor that kills sensitive strains (17,20,21,30,31). Killer strains of S. cerevisiae show an antiyeast spectrum restricted to sensitive Saccharomyces strains except for a report on the killing of Torulopsis glabrata (37).…”

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confidence: 99%

“…Assessment of DBVPG 6076 killer toxin (Kpkt) activity. The frequency of killer toxin activity was evaluated by streak plate agar diffusion assay (21). Approximately 10 5 cells ml Ϫ1 (final concentration) of the strain to be tested for sensitivity to the killer toxin were uniformly suspended in 20 ml of Bacto malt agar (Difco Laboratories, Detroit, Mich.) buffered at pH 4.5 (0.1 M citratephosphate buffer), maintained at 45°C in a water bath, and poured immediately into sterile petri dishes.…”

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confidence: 99%

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Killer Toxin ofKluyveromyces phaffiiDBVPG 6076 as a Biopreservative Agent To Control Apiculate Wine Yeasts

Ciani

Fatichenti

2001

Appl Environ Microbiol

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The use of Kluyveromyces phaffii DBVPG 6076 killer toxin against apiculate wine yeasts has been investigated. The killer toxin of K. phaffii DBVPG 6076 showed extensive anti-Hanseniaspora activity against strains isolated from grape samples. The proteinaceous killer toxin was found to be active in the pH range of 3 to 5 and at temperatures lower than 40°C. These biochemical properties would allow the use of K. phaffii killer toxin in wine making. Fungicidal or fungistatic effects depend on the toxin concentration. Toxin concentrations present in the supernatant during optimal conditions of production (14.3 arbitrary units) exerted a fungicidal effect on a sensitive strain of Hanseniaspora uvarum. At subcritical concentrations (fungistatic effect) the saturation kinetics observed with the increased ratio of killer toxin to H. uvarum cells suggest the presence of a toxin receptor. The inhibitory activity exerted by the killer toxin present in grape juice was comparable to that of sulfur dioxide. The findings presented suggest that the K. phaffii DBVPG 6076 killer toxin has potential as a biopreservative agent in wine making.

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confidence: 99%

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confidence: 99%

Killer Toxin ofKluyveromyces phaffiiDBVPG 6076 as a Biopreservative Agent To Control Apiculate Wine Yeasts

Ciani

Fatichenti

2001

Appl Environ Microbiol

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“…No antifungal activity was detected against B. obtusa (data not shown). Although antifungal activity has been reported for other Kluyveromyces strains (Kluyveromyces phaffii and Kluyveromyces wickerhamii) (21)(22)(23), this protective activity of K. lactis observed against various plant pathogens has not been previously described. Despite this intrinsic antifungal activity, the total observed activity of K. lactis transformants expressing cirsin PSI was always enhanced (Fig.…”

Section: Resultsmentioning

confidence: 82%

Establishing the Yeast Kluyveromyces lactis as an Expression Host for Production of the Saposin-Like Domain of the Aspartic Protease Cirsin

Curto¹,

Lufrano

Pinto

et al. 2014

Appl Environ Microbiol

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Typical plant aspartic protease zymogens comprise a characteristic and plant-specific insert (PSI). PSI domains can interact with membranes, and a role as a defensive weapon against pathogens has been proposed. However, the potential of PSIs as antimicrobial agents has not been fully investigated and explored yet due to problems in producing sufficient amounts of these domains in bacteria. Here, we report the development of an expression platform for the production of the PSI domain of cirsin in the generally regarded as safe (GRAS) yeast Kluyveromyces lactis. We successfully generated K. lactis transformants expressing and secreting significant amounts of correctly processed and glycosylated PSI, as well as its nonglycosylated mutant. A purification protocol with protein yields of ϳ4.0 mg/liter was established for both wild-type and nonglycosylated PSIs, which represents the highest reported yield for a nontagged PSI domain. Subsequent bioactivity assays targeting phytopathogenic fungi indicated that the PSI of cirsin is produced in a biologically active form in K. lactis and provided clear evidence for its antifungal activity. This yeast expression system thereby emerges as a promising production platform for further exploring the biotechnological potential of these plant saposin-like proteins.

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“…Killer toxins were first discovered in Saccharomyces cerevisiae by Makower & Bevan (1963) and they have since been found in numerous other yeast genera (Philliskirk & Young, 1975; Stumm et al, 1977;Rosini, 1983Rosini, , 1985Starmer et al, 1987). Through the following years, killer yeasts and their toxins found applications in several fields.…”

Section: Introductionmentioning

confidence: 99%

Kluyveromyces phaffii killer toxin active against wine spoilage yeasts: purification and characterization

et al. 2004

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The killer toxin secreted by Kluyveromyces phaffii (KpKt) is active against spoilage yeast under winemaking conditions and thus has potential applications in the biocontrol of undesired micro-organisms in the wine industry. Biochemical characterization and N-terminal sequencing of the purified toxin show that KpKt is a glycosylated protein with a molecular mass of 33 kDa. Moreover, it shows 93 % and 80 % identity to a b-1,3-glucanase of Saccharomyces cerevisiae and a b-1,3-glucan transferase of Candida albicans, respectively, and it is active on laminarin and glucan, thus showing a b-glucanase activity. Competitive inhibition of killer activity by cell-wall polysaccharides suggests that glucan (b-1,3 and b-1,6 branched glucans) represents the first receptor site of the toxin on the envelope of the sensitive target. Flow cytometry analysis of the sensitive target after treatment with KpKt and K1 toxin of S. cerevisiae, known to cause loss of cell viability via formation of pores in the cell membrane, suggests a different mode of action for KpKt. INTRODUCTIONKiller toxins were first discovered in Saccharomyces cerevisiae by Makower & Bevan (1963) and they have since been found in numerous other yeast genera (Philliskirk & Young, 1975; Stumm et al., 1977;Rosini, 1983Rosini, , 1985Starmer et al., 1987). Through the following years, killer yeasts and their toxins found applications in several fields. For example, killer yeasts have provided an interesting model for studying the mechanisms involved in the processing and secretion of extracellular proteins, and the identification of killer toxin receptors on the envelope of sensitive targets has helped in the elucidation of the structure and function of the yeast cell wall. Killer yeasts have been used to combat contaminating wild yeasts in the food and fermentation industries, and to control wooddecay basidiomycetes and plant-pathogenic fungi (Young, 1987; Boone et al., 1990;Palpacelli et al., 1991, van Vuuren & Jacobs, 1992Walker et al., 1995). In the medical field, these yeasts have been used in the biotyping of pathogenic yeasts and yeast-like fungi (Morace et al., 1989;Boeckhout & Scorzetti, 1997;Buzzini & Martini, 2001), and in the development of novel antimycotics for the treatment of human and animal fungal infections Seguy et al., 1998; Conti et al., 2002;Schmitt & Breinig, 2002).Recently, it has been shown that Kluyveromyces phaffii (since reclassified as Tetrapisispora phaffii) (Ueda-Nishimura & Mikata, 1999) produces a killer toxin (KpKt) that is active on wine spoilage yeasts (Ciani & Fatichenti, 2001). KpKt has an extensive anti-Hansenispora/Kloeckera activity under winemaking conditions and, therefore, is of particular interest for its potential application as an antimicrobial agent in the wine industry (Ciani & Fatichenti, 2001). At present, the inhibition of wild spoilage yeast at the prefermentative stage is achieved by the addition of SO 2 to freshly pressed must. This antiseptic agent, which has been shown to have a toxic action on humans, is also r...

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The occurrence of killer characters in yeasts

Cited by 48 publications

References 13 publications

Killer Toxin ofKluyveromyces phaffiiDBVPG 6076 as a Biopreservative Agent To Control Apiculate Wine Yeasts

Killer Toxin ofKluyveromyces phaffiiDBVPG 6076 as a Biopreservative Agent To Control Apiculate Wine Yeasts

Establishing the Yeast Kluyveromyces lactis as an Expression Host for Production of the Saposin-Like Domain of the Aspartic Protease Cirsin

Kluyveromyces phaffii killer toxin active against wine spoilage yeasts: purification and characterization

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