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van Wyk N, Badura J, von Wallbrunn C, Pretorius IS. Exploring future applications of the apiculate yeast Hanseniaspora. Crit Rev Biotechnol 2024; 44:100-119. [PMID: 36823717 DOI: 10.1080/07388551.2022.2136565] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/16/2022] [Accepted: 09/24/2022] [Indexed: 02/25/2023]
Abstract
As a metaphor, lemons get a bad rap; however the proverb 'if life gives you lemons, make lemonade' is often used in a motivational context. The same could be said of Hanseniaspora in winemaking. Despite its predominance in vineyards and grape must, this lemon-shaped yeast is underappreciated in terms of its contribution to the overall sensory profile of fine wine. Species belonging to this apiculate yeast are known for being common isolates not just on grape berries, but on many other fruits. They play a critical role in the early stages of a fermentation and can influence the quality of the final product. Their deliberate addition within mixed-culture fermentations shows promise in adding to the complexity of a wine and thus provide sensorial benefits. Hanseniaspora species are also key participants in the fermentations of a variety of other foodstuffs ranging from chocolate to apple cider. Outside of their role in fermentation, Hanseniaspora species have attractive biotechnological possibilities as revealed through studies on biocontrol potential, use as a whole-cell biocatalyst and important interactions with Drosophila flies. The growing amount of 'omics data on Hanseniaspora is revealing interesting features of the genus that sets it apart from the other Ascomycetes. This review collates the fields of research conducted on this apiculate yeast genus.
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Affiliation(s)
- Niël van Wyk
- Department of Microbiology and Biochemistry, Hochschule Geisenheim University, Geisenheim, Germany
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - Jennifer Badura
- Department of Microbiology and Biochemistry, Hochschule Geisenheim University, Geisenheim, Germany
| | - Christian von Wallbrunn
- Department of Microbiology and Biochemistry, Hochschule Geisenheim University, Geisenheim, Germany
| | - Isak S Pretorius
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
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Fredericks LR, Lee MD, Crabtree AM, Boyer JM, Kizer EA, Taggart NT, Roslund CR, Hunter SS, Kennedy CB, Willmore CG, Tebbe NM, Harris JS, Brocke SN, Rowley PA. The Species-Specific Acquisition and Diversification of a K1-like Family of Killer Toxins in Budding Yeasts of the Saccharomycotina. PLoS Genet 2021; 17:e1009341. [PMID: 33539346 PMCID: PMC7888664 DOI: 10.1371/journal.pgen.1009341] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 02/17/2021] [Accepted: 01/05/2021] [Indexed: 12/24/2022] Open
Abstract
Killer toxins are extracellular antifungal proteins that are produced by a wide variety of fungi, including Saccharomyces yeasts. Although many Saccharomyces killer toxins have been previously identified, their evolutionary origins remain uncertain given that many of these genes have been mobilized by double-stranded RNA (dsRNA) viruses. A survey of yeasts from the Saccharomyces genus has identified a novel killer toxin with a unique spectrum of activity produced by Saccharomyces paradoxus. The expression of this killer toxin is associated with the presence of a dsRNA totivirus and a satellite dsRNA. Genetic sequencing of the satellite dsRNA confirmed that it encodes a killer toxin with homology to the canonical ionophoric K1 toxin from Saccharomyces cerevisiae and has been named K1-like (K1L). Genomic homologs of K1L were identified in six non-Saccharomyces yeast species of the Saccharomycotina subphylum, predominantly in subtelomeric regions of the genome. When ectopically expressed in S. cerevisiae from cloned cDNAs, both K1L and its homologs can inhibit the growth of competing yeast species, confirming the discovery of a family of biologically active K1-like killer toxins. The sporadic distribution of these genes supports their acquisition by horizontal gene transfer followed by diversification. The phylogenetic relationship between K1L and its genomic homologs suggests a common ancestry and gene flow via dsRNAs and DNAs across taxonomic divisions. This appears to enable the acquisition of a diverse arsenal of killer toxins by different yeast species for potential use in niche competition.
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Affiliation(s)
- Lance R. Fredericks
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Mark D. Lee
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Angela M. Crabtree
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Josephine M. Boyer
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Emily A. Kizer
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Nathan T. Taggart
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Cooper R. Roslund
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Samuel S. Hunter
- iBEST Genomics Core, University of Idaho, Moscow, Idaho, United States of America
| | - Courtney B. Kennedy
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Cody G. Willmore
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Nova M. Tebbe
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Jade S. Harris
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Sarah N. Brocke
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Paul A. Rowley
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
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Xu S, Yamamoto N. Anti-infective nitazoxanide disrupts transcription of ribosome biogenesis-related genes in yeast. Genes Genomics 2020; 42:915-926. [PMID: 32524281 DOI: 10.1007/s13258-020-00958-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 06/04/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Nitazoxanide is a broad-spectrum, anti-parasitic, anti-protozoal, anti-viral drug, whose mechanisms of action have remained elusive. OBJECTIVE In this study, we aimed to provide insight into the mechanisms of action of nitazoxanide and the related eukaryotic host responses by characterizing transcriptome profiles of Saccharomyces cerevisiae exposed to nitazoxanide. METHODS RNA-Seq was used to investigate the transcriptome profiles of three strains of S. cerevisiae with dsRNA virus-like elements, including a strain that hosts M28 encoding the toxic protein K28. From the strain with M28, an additional sub-strain was prepared by excluding M28 using a nitazoxanide treatment. RESULTS Our transcriptome analysis revealed the effects of nitazoxanide on ribosome biogenesis. Many genes related to the UTP A, UTP B, Mpp10-Imp3-Imp4, and Box C/D snoRNP complexes were differentially regulated by nitazoxanide exposure in all of the four tested strains/sub-strains. Examples of the differentially regulated genes included UTP14, UTP4, NOP4, UTP21, UTP6, and IMP3. The comparison between the M28-laden and non-M28-laden sub-strains showed that the mitotic cell cycle was more significantly affected by nitazoxanide exposure in the non-M28-laden sub-strain. CONCLUSIONS Overall, our study reveals that nitazoxanide disrupts regulation of ribosome biogenesis-related genes in yeast.
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Affiliation(s)
- Siyu Xu
- Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, 08826, South Korea
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Naomichi Yamamoto
- Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, 08826, South Korea.
- Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, 08826, South Korea.
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Yeast population dynamics reveal a potential ‘collaboration’ between Metschnikowia pulcherrima and Saccharomyces uvarum for the production of reduced alcohol wines during Shiraz fermentation. Appl Microbiol Biotechnol 2014; 99:1885-95. [DOI: 10.1007/s00253-014-6193-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/18/2014] [Accepted: 10/22/2014] [Indexed: 11/29/2022]
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Affiliation(s)
- James A Barnett
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
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Abstract
Since the discovery of toxin-secreting killer yeasts more than 40 years ago, research into this phenomenon has provided insights into eukaryotic cell biology and virus-host-cell interactions. This review focuses on the most recent advances in our understanding of the basic biology of virus-carrying killer yeasts, in particular the toxin-encoding killer viruses, and the intracellular processing, maturation and toxicity of the viral protein toxins. The strategy of using eukaryotic viral toxins to effectively penetrate and eventually kill a eukaryotic target cell will be discussed, and the cellular mechanisms of self-defence and protective immunity will also be addressed.
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Affiliation(s)
- Manfred J Schmitt
- Applied Molecular Biology, University of the Saarland, D-66041 Saarbrücken, Germany.
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Masoud W, Kaltoft CH. The effects of yeasts involved in the fermentation of Coffea arabica in East Africa on growth and ochratoxin A (OTA) production by Aspergillus ochraceus. Int J Food Microbiol 2006; 106:229-34. [PMID: 16213049 DOI: 10.1016/j.ijfoodmicro.2005.06.015] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2005] [Revised: 04/16/2005] [Accepted: 06/30/2005] [Indexed: 11/23/2022]
Abstract
The effects of Pichia anomala, Pichia kluyveri and Hanseniaspora uvarum predominant during coffee processing on growth of Aspergillus ochraceus and production of ochratoxin A (OTA) on malt extract agar (MEA) and on coffee agar (CA) were studied. The three yeasts were able to inhibit growth of A. ochraceus when co-cultured in MEA and CA. Growth inhibition was significantly higher on MEA than on CA. Furthermore, P. anomala and P. kluyveri were found to have a stronger effect on growth of A. ochraceus than H. uvarum. The three yeasts were able to prevent spore germination of A. ochraceus in yeast glucose peptone (MYGP) broth. In yeast-free supernatant of MYGP broth after an incubation period of 72 h, spores of A. ochraceus were able to germinate with very short germ tubes, but further development of the germ tubes was inhibited. The three yeasts decreased the pH of MYGP broth from 5.6 to a range of 4.4-4.7, which was found to have no effect on spore germination of A. ochraceus. P. anomala, P. kluyveri and H. uvarum were able to prevent production of OTA by A. ochraceus when co-cultured on MEA. On CA medium, P. anomala and P. kluyveri prevented A. ochraceus from producing OTA. H. uvarum did not affect production of OTA by A. ochraceus on CA medium.
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Affiliation(s)
- Wafa Masoud
- Department of Food Science, Food Microbiology, The Royal Veterinary and Agricultural University, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark.
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Leverentz B, Conway WS, Janisiewicz W, Abadias M, Kurtzman CP, Camp MJ. Biocontrol of the food-borne pathogens Listeria monocytogenes and Salmonella enterica serovar Poona on fresh-cut apples with naturally occurring bacterial and yeast antagonists. Appl Environ Microbiol 2006; 72:1135-40. [PMID: 16461659 PMCID: PMC1392892 DOI: 10.1128/aem.72.2.1135-1140.2006] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 11/19/2005] [Indexed: 11/20/2022] Open
Abstract
Fresh-cut apples contaminated with either Listeria monocytogenes or Salmonella enterica serovar Poona, using strains implicated in outbreaks, were treated with one of 17 antagonists originally selected for their ability to inhibit fungal postharvest decay on fruit. While most of the antagonists increased the growth of the food-borne pathogens, four of them, including Gluconobacter asaii (T1-D1), a Candida sp. (T4-E4), Discosphaerina fagi (ST1-C9), and Metschnikowia pulcherrima (T1-E2), proved effective in preventing the growth or survival of food-borne human pathogens on fresh-cut apple tissue. The contaminated apple tissue plugs were stored for up to 7 days at two different temperatures. The four antagonists survived or grew on the apple tissue at 10 or 25 degrees C. These four antagonists reduced the Listeria monocytogenes populations and except for the Candida sp. (T4-E4), also reduced the S. enterica serovar Poona populations. The reduction was higher at 25 degrees C than at 10 degrees C, and the growth of the antagonists, as well as pathogens, increased at the higher temperature.
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Affiliation(s)
- Britta Leverentz
- Produce Quality and Safety Laboratory, Henry A. Wallace Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA
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Michalčáková S, Sulo P, Sláviková E. Killer yeasts ofKluyveromycesandHansenulagenera with potential application in fermentation and therapy. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/abio.370130406] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Since the initial discovery of the yeast killer system almost 40 years ago, intensive studies have substantially strengthened our knowledge in many areas of biology and provided deeper insights into basic aspects of eukaryotic cell biology as well as into virus-host cell interactions and general yeast virology. Analysis of killer toxin structure, synthesis and secretion has fostered understanding of essential cellular mechanisms such as post-translational prepro-protein processing in the secretory pathway. Furthermore, investigation of the receptor-mediated mode of toxin action proved to be an effective means for dissecting the molecular structure and in vivo assembly of yeast and fungal cell walls, providing important insights relevant to combating infections by human pathogenic yeasts. Besides their general importance in understanding eukaryotic cell biology, killer yeasts, killer toxins and killer viruses are also becoming increasingly interesting with respect to possible applications in biomedicine and gene technology. This review will try to address all these aspects.
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Affiliation(s)
- Manfred J Schmitt
- Angewandte Molekularbiologie (FR 8.3 -- Mikrobiologie), Universität des Saarlandes, Im Stadtwald, Gebäude 2, D-66123 Saarbrücken, Germany.
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Marquina D, Barroso J, Santos A, Peinado JM. Production and characteristics of Debaryomyces hansenii killer toxin. Microbiol Res 2002; 156:387-91. [PMID: 11770858 DOI: 10.1078/0944-5013-00117] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The optimal conditions for the production of the killer toxin of Debaryomyces hansenii CYC 1021 have been studied. The lethal activity of the killer toxin increased with the presence of NaCl in the medium used for testing the killing action. Production of the killer toxin was stimulated in the presence of proteins of complex culture media. Addition of nonionic detergents and other additives, such as dimethylsulfoxide enhanced killer toxin production significantly. Killer toxin secretion pattern followed the growth curve and reached its maximum activity at the early stationary phase. Optimal stability was observed at pH 4.5 and temperatures up to 20 degrees C. Above pH 4.5 a steep decrease of the stability was noted. The activity was hardly detectable at pH 5.1.
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Affiliation(s)
- D Marquina
- Department of Microbiology, Biology Faculty, Complutense University of Madrid, 28040 Madrid, Spain.
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Chen WB, Han YF, Jong SC, Chang SC. Isolation, purification, and characterization of a killer protein from Schwanniomyces occidentalis. Appl Environ Microbiol 2000; 66:5348-52. [PMID: 11097913 PMCID: PMC92467 DOI: 10.1128/aem.66.12.5348-5352.2000] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The yeast Schwanniomyces occidentalis produces a killer toxin lethal to sensitive strains of Saccharomyces cerevisiae. Killer activity is lost after pepsin and papain treatment, suggesting that the toxin is a protein. We purified the killer protein and found that it was composed of two subunits with molecular masses of approximately 7.4 and 4.9 kDa, respectively, but was not detectable with periodic acid-Schiff staining. A BLAST search revealed that residues 3 to 14 of the 4.9-kDa subunit had 75% identity and 83% similarity with killer toxin K2 from S. cerevisiae at positions 271 to 283. Maximum killer activity was between pH 4.2 and 4.8. The protein was stable between pH 2.0 and 5.0 and inactivated at temperatures above 40 degrees C. The killer protein was chromosomally encoded. Mannan, but not beta-glucan or laminarin, prevented sensitive yeast cells from being killed by the killer protein, suggesting that mannan may bind to the killer protein. Identification and characterization of a killer strain of S. occidentalis may help reduce the risk of contamination by undesirable yeast strains during commercial fermentations.
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Affiliation(s)
- W B Chen
- Department of Biochemistry, National Yang-Ming University, Taipei 112, Taiwan, Republic of China
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MATHEWS HL, CONTI S, WITEK-JANUSEK L, POLONELLI L. Effect of Pichia anomala killer toxin on Candida albicans. Med Mycol 1998. [DOI: 10.1046/j.1365-280x.1998.00138.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Mathews H, Conti S, Witek-Janusek L, Polonelli L. Effect ofPichia anomalakiller toxin onCandida albicans. Med Mycol 1998. [DOI: 10.1080/02681219880000301] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Weinstein LA, Capaldo-Kimball F, Leibowitz MJ. Genetics of heat-curability of killer virus of yeast. Yeast 1993; 9:411-8. [PMID: 7685559 DOI: 10.1002/yea.320090411] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The cytoplasmically inherited M double-stranded (ds) RNA genome segment of killer virus of Saccharomyces cerevisiae is heat-curable in some yeast strains but not in others. Temperature sensitivity is conferred on both M1 and M2 dsRNA satellite virus segments by the L-A-HN allele of the killer helper virus genome, but not by the L-A-H allele. Both diploidy and mating type heterozygosity of the host cell are also correlated with increased virus curability.
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Affiliation(s)
- L A Weinstein
- Department of Molecular Genetics and Microbiology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway 08854-5635
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Abstract
The cytoplasmic L-A dsRNA virus of Saccharomyces cerevisiae consists of a 4.5 kb dsRNA and the two gene products it encodes; the capsid (cap) and at least one copy of the capsid-polymerase (cap-pol) fusion protein. Virion cap-pol catalyses transcription of the plus (sense)-strand; this is extruded from the virus and serves as messenger for synthesis of cap and cap-pol. Nascent cap-pol binds to a specific domain in the plus strand to initiate encapsidation and then catalyses minus-strand synthesis to complete the replication cycle. Products of at least three host genes are required for replication, and virus copy number is kept at tolerable levels by the SKI antivirus system. S. cerevisiae killer viruses are satellite dsRNAs that use a similar encapsidation domain to parasitize the L-A replication machinery. They encode precursors of secreted polypeptide toxins and immunity (specific resistance) determinants and are self-selecting. Three unique killer types, K1, K2 and K28, are currently recognized. They are distinguished by an absence of cross-immunity and by toxin properties and lethal mechanisms; while K1 and K2 toxins bind to cell-wall glucan and disrupt membrane functions, K28 toxin binds to mannoprotein and causes inhibition of DNA synthesis.
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Affiliation(s)
- D J Tipper
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester 01655
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Wingfield BD, Van Der Meer LJ, Pretorius IS, Van Vuuren HJ. K3 killer yeast is a mutant K2 killer yeast. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/s0953-7562(09)81304-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Worsham PL, Bolen PL. Killer toxin production in Pichia acaciae is associated with linear DNA plasmids. Curr Genet 1990; 18:77-80. [PMID: 2245477 DOI: 10.1007/bf00321119] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have identified a strain of the yeast Pichia acaciae which produces a "killer" toxin active against the yeast Debaryomyces tamarii. The killer phenotype was associated with the presence of two DNA plasmids, pPacl-1 (13.6 kilobase pairs) and pPacl-2 (7.3 kilobase pairs). P. acaciae strains, cured of these plasmids by irradiation with ultraviolet light, lacked killer activity and were sensitive to toxin produced by the parental strain. A partially cured strain, GS-1215, missing only the smaller plasmid, pPacl-2, also exhibited loss of both toxin activity and immunity. Exonuclease studies revealed that both plasmids were linear double-stranded DNA molecules with 5' protected ends. The P. acaciae system differs from that of the well-studied Kluyveromyces lactis "killer" system both in the range of susceptible strains and in the sizes of the plasmids involved. Our studies contradict previous reports that Pichia killer systems are invariably chromosomal.
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Affiliation(s)
- P L Worsham
- Agricultural Research Service, U.S. Department of Agriculture, Peoria 61604
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Abstract
The yeast Hanseniaspora uvarum liberates a killer toxin lethal to sensitive strains of the species Saccharomyces cerevisiae. Secretion of this killer toxin was inhibited by tunicamycin, an inhibitor of N-glycosylation, although the mature killer protein did not show any detectable carbohydrate structures. Culture supernatants of the killer strain were concentrated by ultrafiltration and the extracellular killer toxin was precipitated with ethanol and purified by ion exchange chromatography. SDS-PAGE of the electrophoretically homogenous killer protein indicated an apparent molecular mass of 18,000. Additional investigations of the primary toxin binding sites within the cell wall of sensitive yeast strains showed that the killer toxin of Hanseniaspora uvarum is bound by beta-1, 6-D-glucans.
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Affiliation(s)
- F Radler
- Institut für Mikrobiologie und Weinforschung der Johannes Gutenberg-Universität, Mainz, Federal Republic of Germany
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Wingfield BD, Southgate VJ, Pretorius IS, van Vuuren HJ. A K2 neutral Saccharomyces cerevisiae strain contains a variant K2 M genome. Yeast 1990; 6:159-69. [PMID: 2183523 DOI: 10.1002/yea.320060210] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
K2 neutral strain Saccharomyces cerevisiae USM12 was identified and characterized. This strain carried an M double-stranded RNA (dsRNA) genome encoding for resistance to K2 toxin. The M dsRNA was larger than the K2 killer yeast M dsRNA and homoduplex analysis of denatured and reannealed K2 neurtal M dsRNA revealed an inverted duplication. Heteroduplex analysis showed that two thirds of the K2 M genome had homology with the K2 neutral M genome. Hybridization showed that the USM12 M dsRNA had significant homology with the K2 M dsRNA. Protein profiles of extracellular proteins from USM12 and a cured strain indicated that USM12 did not secrete any toxin. This is the first time that a K2 neutral yeast strain has been characterized.
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Affiliation(s)
- B D Wingfield
- Department of Microbiology, University of Stellenbosch, South Africa
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Cansado J, Longo E, Agrelo D, Villa TG. Curing of the killer character ofSaccharomyces cerevisiaewith acridine orange. FEMS Microbiol Lett 1989. [DOI: 10.1111/j.1574-6968.1989.tb03628.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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