Characterization, Ecological Distribution, and Population Dynamics of Saccharomyces Sensu Stricto Killer Yeasts in the Spontaneous Grape Must Fermentations of Southwestern Spain

ABSTRACTKiller yeasts secrete protein toxins that are lethal to sensitive strains of the same or related yeast species. Among the four types ofSaccharomyceskiller yeasts already described (K1, K2, K28, and Klus), we found K2 and Klus killer yeasts in spontaneous wine fermentations from southwestern Spain. Both phenotypes were encoded by medium-size double-stranded RNA (dsRNA) viruses,Saccharomyces cerevisiaevirus (ScV)-M2 and ScV-Mlus, whose genome sizes ranged from 1.3 to 1.75 kb and from 2.1 to 2.3 kb, respectively. The K2 yeasts were found in all the wine-producing subareas for all the vintages analyzed, while the Klus yeasts were found in the warmer subareas and mostly in the warmer ripening/harvest seasons. The middle-size isotypes of the M2 dsRNA were the most frequent among K2 yeasts, probably because they encoded the most intense K2 killer phenotype. However, the smallest isotype of the Mlus dsRNA was the most frequent for Klus yeasts, although it encoded the least intense Klus killer phenotype. The killer yeasts were present in most (59.5%) spontaneous fermentations. Most were K2, with Klus being the minority. The proportion of killer yeasts increased during fermentation, while the proportion of sensitive yeasts decreased. The fermentation speed, malic acid, and wine organoleptic quality decreased in those fermentations where the killer yeasts replaced at least 15% of a dominant population of sensitive yeasts, while volatile acidity and lactic acid increased, and the amount of bacteria in the tumultuous and the end fermentation stages also increased in an unusual way.

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Method-Dependent Epidemiological Cutoff Values for Detection of Triazole Resistance in Candida and Aspergillus Species for the Sensititre YeastOne Colorimetric Broth and Etest Agar Diffusion Methods

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01651-18 ◽

2018 ◽

Vol 63 (1) ◽

Cited By ~ 19

Author(s):

A. Espinel-Ingroff ◽

J. Turnidge ◽

A. Alastruey-Izquierdo ◽

F. Botterel ◽

E. Canton ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Species Complex ◽

Susceptibility Testing ◽

Yeast Species ◽

Sensu Stricto ◽

Wild Type ◽

Pichia Kudriavzevii ◽

Cutoff Value ◽

Content Type ◽

Clavispora Lusitaniae

ABSTRACT Although the Sensititre Yeast-One (SYO) and Etest methods are widely utilized, interpretive criteria are not available for triazole susceptibility testing of Candida or Aspergillus species. We collected fluconazole, itraconazole, posaconazole, and voriconazole SYO and Etest MICs from 39 laboratories representing all continents for (method/agent-dependent) 11,171 Candida albicans, 215 C. dubliniensis, 4,418 C. glabrata species complex, 157 C. guilliermondii (Meyerozyma guilliermondii), 676 C. krusei (Pichia kudriavzevii), 298 C. lusitaniae (Clavispora lusitaniae), 911 C. parapsilosis sensu stricto, 3,691 C. parapsilosis species complex, 36 C. metapsilosis, 110 C. orthopsilosis, 1,854 C. tropicalis, 244 Saccharomyces cerevisiae, 1,409 Aspergillus fumigatus, 389 A. flavus, 130 A. nidulans, 233 A. niger, and 302 A. terreus complex isolates. SYO/Etest MICs for 282 confirmed non-wild-type (non-WT) isolates were included: ERG11 (C. albicans), ERG11 and MRR1 (C. parapsilosis), cyp51A (A. fumigatus), and CDR2 and CDR1 overexpression (C. albicans and C. glabrata, respectively). Interlaboratory modal agreement was superior by SYO for yeast species and by the Etest for Aspergillus spp. Distributions fulfilling CLSI criteria for epidemiological cutoff value (ECV) definition were pooled, and we proposed SYO ECVs for S. cerevisiae and 9 yeast and 3 Aspergillus species and Etest ECVs for 5 yeast and 4 Aspergillus species. The posaconazole SYO ECV of 0.06 µg/ml for C. albicans and the Etest itraconazole ECV of 2 µg/ml for A. fumigatus were the best predictors of non-WT isolates. These findings support the need for method-dependent ECVs, as, overall, the SYO appears to perform better for susceptibility testing of yeast species and the Etest appears to perform better for susceptibility testing of Aspergillus spp. Further evaluations should be conducted with more Candida mutants.

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Heterodimers as the Structural Unit of the T=1 Capsid of the Fungal Double-Stranded RNA Rosellinia necatrix Quadrivirus 1

Journal of Virology ◽

10.1128/jvi.01013-16 ◽

2016 ◽

Vol 90 (24) ◽

pp. 11220-11230 ◽

Cited By ~ 14

Author(s):

Daniel Luque ◽

Carlos P. Mata ◽

Fernando González-Camacho ◽

José M. González ◽

Josué Gómez-Blanco ◽

...

Keyword(s):

Electron Microscopy ◽

Molecular Sieves ◽

Three Dimensional ◽

Rosellinia Necatrix ◽

Double Stranded Rna ◽

Content Type ◽

Cryo Electron Microscopy ◽

Wide Range ◽

The Family ◽

Dsrna Viruses

ABSTRACTMost double-stranded RNA (dsRNA) viruses are transcribed and replicated in a specialized icosahedral capsid with a T=1 lattice consisting of 60 asymmetric capsid protein (CP) dimers. These capsids help to organize the viral genome and replicative complex(es). They also act as molecular sieves that isolate the virus genome from host defense mechanisms and allow the passage of nucleotides and viral transcripts. Rosellinia necatrix quadrivirus 1 (RnQV1), the type species of the familyQuadriviridae, is a dsRNA fungal virus with a multipartite genome consisting of four monocistronic segments (segments 1 to 4). dsRNA-2 and dsRNA-4 encode two CPs (P2 and P4, respectively), which coassemble into ∼450-Å-diameter capsids. We used three-dimensional cryo-electron microscopy combined with complementary biophysical techniques to determine the structures of RnQV1 virion strains W1075 and W1118. RnQV1 has a quadripartite genome, and the capsid is based on a single-shelled T=1 lattice built of P2-P4 dimers. Whereas the RnQV1-W1118 capsid is built of full-length CP, P2 and P4 of RnQV1-W1075 are cleaved into several polypeptides, maintaining the capsid structural organization. RnQV1 heterodimers have a quaternary organization similar to that of homodimers of reoviruses and other dsRNA mycoviruses. The RnQV1 capsid is the first T=1 capsid with a heterodimer as an asymmetric unit reported to date and follows the architectural principle for dsRNA viruses that a 120-subunit capsid is a conserved assembly that supports dsRNA replication and organization.IMPORTANCEGiven their importance to health, members of the familyReoviridaeare the basis of most structural and functional studies and provide much of our knowledge of dsRNA viruses. Analysis of bacterial, protozoal, and fungal dsRNA viruses has improved our understanding of their structure, function, and evolution, as well. Here, we studied a dsRNA virus that infects the fungusRosellinia necatrix, an ascomycete that is pathogenic to a wide range of plants. Using three-dimensional cryo-electron microscopy and analytical ultracentrifugation analysis, we determined the structure and stoichiometry of Rosellinia necatrix quadrivirus 1 (RnQV1). The RnQV1 capsid is a T=1 capsid with 60 heterodimers as the asymmetric units. The large amount of genetic information used by RnQV1 to construct a simple T=1 capsid is probably related to the numerous virus-host and virus-virus interactions that it must face in its life cycle, which lacks an extracellular phase.

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Scent of a killer: How killer yeast boost its dispersal

10.22541/au.161601343.37863473/v1 ◽

2021 ◽

Author(s):

Claudia Buser ◽

Jukka Jokela ◽

Oliver Martin

Keyword(s):

Helper Virus ◽

Insect Vectors ◽

Double Stranded Rna ◽

Killer Yeast ◽

Yeast Strains ◽

Killer Yeasts ◽

Host Odor ◽

Vector Borne ◽

Dsrna Viruses ◽

New Habitats

Vector-borne parasites often manipulate hosts to attract uninfected vectors. For example, parasites causing malaria alter host odor to attract mosquitoes. Here we discuss the ecology and evolution of fruit-colonizing yeast in a tripartite symbiosis – the so-called “killer yeast” system. “Killer yeast” consists of Saccharomyces cerevisiae yeast hosting two double stranded RNA viruses (M satellite dsRNAs, L-A dsRNA helper virus). When both dsRNA viruses occur in a yeast cell, the yeast converts to lethal toxin‑producing “killer yeast” phenotype that kills uninfected yeasts. Yeasts on ephemeral fruits attract insect vectors to colonize new habitats. As the viruses have no extracellular stage, they depend on the same insect vectors as yeast for their dispersal. Viruses also benefit from yeast dispersal as this promotes yeast to reproduce sexually, which is how viruses can transmit to uninfected yeast strains. We tested whether insect vectors are more attracted to killer yeasts than to non‑killer yeasts. In our field experiment, we found that killer yeasts were more attractive to Drosophila than non-killer yeasts. This suggests that vectors foraging on yeast are more likely to transmit yeast with a killer phenotype, allowing the viruses to colonize those uninfected yeast strains that engage in sexual reproduction with the killer yeast. Beyond insights into the basic ecology of the killer yeast system, our results suggest that viruses could increase transmission success by manipulating the insect vectors of their host.

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Structure of a Protozoan Virus from the Human Genitourinary Parasite Trichomonas vaginalis

mBio ◽

10.1128/mbio.00056-13 ◽

2013 ◽

Vol 4 (2) ◽

Cited By ~ 24

Author(s):

Kristin N. Parent ◽

Yuko Takagi ◽

Giovanni Cardone ◽

Norman H. Olson ◽

Maria Ericsson ◽

...

Keyword(s):

Viral Genome ◽

Trichomonas Vaginalis ◽

Transmitted Disease ◽

Three Dimensional ◽

Dimensional Structure ◽

Ribosomal Frameshifting ◽

Double Stranded Rna ◽

Content Type ◽

Sexually Transmitted ◽

Dsrna Viruses

ABSTRACTThe flagellated protozoanTrichomonas vaginalisis an obligate human genitourinary parasite and the most frequent cause of sexually transmitted disease worldwide. Most clinical isolates ofT. vaginalisare persistently infected with one or more double-stranded RNA (dsRNA) viruses from the genusTrichomonasvirus, familyTotiviridae, which appear to influence not only protozoan biology but also human disease. Here we describe the three-dimensional structure ofTrichomonas vaginalisvirus 1 (TVV1) virions, as determined by electron cryomicroscopy and icosahedral image reconstruction. The structure reveals aT= 1 capsid comprising 120 subunits, 60 in each of two nonequivalent positions, designated A and B, as previously observed for fungalTotiviridaefamily members. The putative protomer is identified as an asymmetric AB dimer consistent with either decamer or tetramer assembly intermediates. The capsid surface is notable for raised plateaus around the icosahedral 5-fold axes, with canyons connecting the 2- and 3-fold axes. Capsid-spanning channels at the 5-fold axes are unusually wide and may facilitate release of the viral genome, promoting dsRNA-dependent immunoinflammatory responses, as recently shown upon the exposure of human cervicovaginal epithelial cells to either TVV-infectedT. vaginalisor purified TVV1 virions. Despite extensive sequence divergence, conservative features of the capsid reveal a helix-rich fold probably derived from an ancestor shared with fungalTotiviridaefamily members. Also notable are mass spectrometry results assessing the virion proteins as a complement to structure determination, which suggest that translation of the TVV1 RNA-dependent RNA polymerase in fusion with its capsid protein involves −2, and not +1, ribosomal frameshifting, an uncommonly found mechanism to date.IMPORTANCETrichomonas vaginaliscauses ~250 million new cases of sexually transmitted disease each year worldwide and is associated with serious complications, including premature birth and increased transmission of other pathogens, including HIV. It is an extracellular parasite that, in turn, commonly hosts infections with double-stranded RNA (dsRNA) viruses, trichomonasviruses, which appear to exacerbate disease through signaling of immunoinflammatory responses by human epithelial cells. Here we report the first three-dimensional structure of a trichomonasvirus, which is also the first such structure of any protozoan dsRNA virus; show that it has unusually wide channels at the capsid vertices, with potential for releasing the viral genome and promoting dsRNA-dependent responses by human cells; and provide evidence that it uses −2 ribosomal frameshifting, an uncommon mechanism, to translate its RNA polymerase in fusion with its capsid protein. These findings provide both mechanistic and translational insights concerning the role of trichomonasviruses in aggravating disease attributable toT. vaginalis.

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Atomic Structure of the Trichomonas vaginalis Double-Stranded RNA Virus 2

mBio ◽

10.1128/mbio.02924-20 ◽

2021 ◽

Vol 12 (2) ◽

Author(s):

Alexander Stevens ◽

Katherine Muratore ◽

Yanxiang Cui ◽

Patricia J. Johnson ◽

Z. Hong Zhou

Keyword(s):

Trichomonas Vaginalis ◽

Atomic Model ◽

Causative Pathogen ◽

Structural Comparison ◽

Double Stranded Rna ◽

Content Type ◽

Sexually Transmitted ◽

Shell Protein ◽

Capsid Shell ◽

Dsrna Viruses

ABSTRACT Trichomonas vaginalis, the causative pathogen for the most common nonviral sexually transmitted infection worldwide, is itself frequently infected with one or more of the four types of small double-stranded RNA (dsRNA) Trichomonas vaginalis viruses (TVV1 to 4, genus Trichomonasvirus, family Totiviridae). Each TVV encloses a nonsegmented genome within a single-layered capsid and replicates entirely intracellularly, like many dsRNA viruses, and unlike those in the Reoviridae family. Here, we have determined the structure of TVV2 by cryo-electron microscopy (cryoEM) at 3.6 Å resolution and derived an atomic model of its capsid. TVV2 has an icosahedral, T = 2*, capsid comprised of 60 copies of the icosahedral asymmetric unit (a dimer of the two capsid shell protein [CSP] conformers, CSP-A and CSP-B), typical of icosahedral dsRNA virus capsids. However, unlike the robust CSP-interlocking interactions such as the use of auxiliary “clamping” proteins among Reoviridae, only lateral CSP interactions are observed in TVV2, consistent with an assembly strategy optimized for TVVs’ intracellular-only replication cycles within their protozoan host. The atomic model reveals both a mostly negatively charged capsid interior, which is conducive to movement of the loosely packed genome, and channels at the 5-fold vertices, which we suggest as routes of mRNA release during transcription. Structural comparison of TVV2 to the Saccharomyces cerevisiae L-A virus reveals a conserved helix-rich fold within the CSP and putative guanylyltransferase domain along the capsid exterior, suggesting conserved mRNA maintenance strategies among Totiviridae. This first atomic structure of a TVV provides a framework to guide future biochemical investigations into the interplay between Trichomonas vaginalis and its viruses. IMPORTANCE Trichomonas vaginalis viruses (TVVs) are double-stranded RNA (dsRNA) viruses that cohabitate in Trichomonas vaginalis, the causative pathogen of trichomoniasis, the most common nonviral sexually transmitted disease worldwide. Featuring an unsegmented dsRNA genome encoding a single capsid shell protein (CSP), TVVs contrast with multisegmented dsRNA viruses, such as the diarrhea-causing rotavirus, whose larger genome is split into 10 dsRNA segments encoding 5 unique capsid proteins. To determine how TVVs incorporate the requisite functionalities for viral replication into their limited proteome, we derived the atomic model of TVV2, a first for TVVs. Our results reveal the intersubunit interactions driving CSP association for capsid assembly and the properties that govern organization and maintenance of the viral genome. Structural comparison between TVV2 capsids and those of distantly related dsRNA viruses indicates conserved strategies of nascent RNA release and a putative viral guanylyltransferase domain implicated in the cytoplasmic maintenance of viral messenger and genomic RNA.

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A Novel Taxon of Monosegmented Double-Stranded RNA Viruses Endemic to Triclad Flatworms

Journal of Virology ◽

10.1128/jvi.00623-20 ◽

2020 ◽

Vol 94 (22) ◽

Author(s):

Jeffrey T. A. Burrows ◽

Delphine Depierreux ◽

Max L. Nibert ◽

Bret J. Pearson

Keyword(s):

Stem Cell ◽

Tissue Regeneration ◽

Cell Biology ◽

Stem Cell Biology ◽

Schmidtea Mediterranea ◽

Pathogenic Potential ◽

Double Stranded Rna ◽

Content Type ◽

Host System ◽

Dsrna Viruses

ABSTRACT Freshwater planarians, flatworms from order Tricladida, are experimental models of stem cell biology and tissue regeneration. An aspect of their biology that remains less well studied is their relationship with viruses that may infect them. In this study, we identified a taxon of monosegmented double-stranded RNA (dsRNA) viruses in five planarian species, including the well-characterized model Schmidtea mediterranea. Sequences for the S. mediterranea virus (abbreviated SmedTV for S. mediterranea tricladivirus) were found in public transcriptome data from multiple institutions, indicating that SmedTV is prevalent in S. mediterranea lab colonies, though without causing evident disease. The presence of SmedTV in discrete cells was shown through in situ hybridization methods for detecting the viral RNA. SmedTV-staining cells were found to be concentrated in neural structures (eyes and brain) but were also scattered in other worm tissues as well. In contrast, few SmedTV-staining cells were seen in stem cell compartments (also consistent with RNA sequencing data) or early blastema tissue. RNA interference (RNAi) targeted to the SmedTV sequence led to apparent cure of infection, though effects on worm health or behavior were not observed. Efforts to transmit SmedTV horizontally through microinjection were unsuccessful. Based on these findings, we conclude that SmedTV infects S. mediterranea in a persistent manner and undergoes vertical transmission to progeny worms during serial passage in lab colonies. The utility of S. mediterranea as a regeneration model, coupled with the apparent capacity of SmedTV to evade normal host immune/RNAi defenses under standard conditions, argues that further studies are warranted to explore this newly recognized virus-host system. IMPORTANCE Planarians are freshwater flatworms, related more distantly to tapeworms and flukes, and have been developed as models to study the molecular mechanisms of stem cell biology and tissue regeneration. These worms live in aquatic environments, where they are likely to encounter a variety of viruses, bacteria, and eukaryotic organisms with pathogenic potential. How the planarian immune system has evolved to cope with these potential pathogens is not well understood, and only two types of planarian viruses have been described to date. Here, we report discovery and inaugural studies of a novel taxon of dsRNA viruses in five different planarian species. The virus in the best-characterized model species, Schmidtea mediterranea, appears to persist long term in that host while avoiding endogenous antiviral or RNAi mechanisms. The S. mediterranea virus-host system thus seems to offer opportunity for gaining new insights into host defenses and their evolution in an important lab model.

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Three-Dimensional Structure of a Protozoal Double-Stranded RNA Virus That Infects the Enteric Pathogen Giardia lamblia

Journal of Virology ◽

10.1128/jvi.02745-14 ◽

2014 ◽

Vol 89 (2) ◽

pp. 1182-1194 ◽

Cited By ~ 25

Author(s):

Mandy E. W. Janssen ◽

Yuko Takagi ◽

Kristin N. Parent ◽

Giovanni Cardone ◽

Max L. Nibert ◽

...

Keyword(s):

Image Reconstruction ◽

Giardia Lamblia ◽

Trichomonas Vaginalis ◽

Enteric Pathogen ◽

Dsrna Virus ◽

Cell Entry ◽

Electron Cryomicroscopy ◽

Double Stranded Rna ◽

Content Type ◽

Dsrna Viruses

ABSTRACTGiardia lambliavirus (GLV) is a small, nonenveloped, nonsegmented double-stranded RNA (dsRNA) virus infectingGiardia lamblia, the most common protozoan pathogen of the human intestine and a major agent of waterborne diarrheal disease worldwide. GLV (genusGiardiavirus) is a member of familyTotiviridae, along with several other groups of protozoal or fungal viruses, includingLeishmaniaRNA viruses andTrichomonas vaginalisviruses. Interestingly, GLV is more closely related than otherTotiviridaemembers to a group of recently discovered metazoan viruses that includes penaeid shrimp infectious myonecrosis virus (IMNV). Moreover, GLV is the only known protozoal dsRNA virus that can transmit efficiently by extracellular means, also like IMNV. In this study, we used transmission electron cryomicroscopy and icosahedral image reconstruction to examine the GLV virion at an estimated resolution of 6.0 Å. Its outermost diameter is 485 Å, making it the largest totivirus capsid analyzed to date. Structural comparisons of GLV and other totiviruses highlighted a related “T=2” capsid organization and a conserved helix-rich fold in the capsid subunits. In agreement with its unique capacity as a protozoal dsRNA virus to survive and transmit through extracellular environments, GLV was found to be more thermoresistant thanTrichomonas vaginalisvirus 1, but no specific protein machinery to mediate cell entry, such as the fiber complexes in IMNV, could be localized. These and other structural and biochemical findings provide a basis for future work to dissect the cell entry mechanism of GLV into a “primitive” (early-branching) eukaryotic host and an important enteric pathogen of humans.IMPORTANCENumerous pathogenic bacteria, includingCorynebacterium diphtheriae,Salmonella enterica, andVibrio cholerae, are infected with lysogenic bacteriophages that contribute significantly to bacterial virulence. In line with this phenomenon, several pathogenic protozoa, includingGiardia lamblia,Leishmaniaspecies, andTrichomonas vaginalisare persistently infected with dsRNA viruses, and growing evidence indicates that at least some of these protozoal viruses can likewise enhance the pathogenicity of their hosts. Understanding of these protozoal viruses, however, lags far behind that of many bacteriophages. Here, we investigated the dsRNA virus that infects the widespread enteric parasiteGiardia lamblia. Using electron cryomicroscopy and icosahedral image reconstruction, we determined the virion structure of Giardia lamblia virus, obtaining new information relating to its assembly, stability, functions in cell entry and transcription, and similarities and differences with other dsRNA viruses. The results of our study set the stage for further mechanistic work on the roles of these viruses in protozoal virulence.

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Relationships and Evolution of Double-Stranded RNA Totiviruses of Yeasts Inferred from Analysis of L-A-2 and L-BC Variants in Wine Yeast Strain Populations

Applied and Environmental Microbiology ◽

10.1128/aem.02991-16 ◽

2016 ◽

Vol 83 (4) ◽

Cited By ~ 10

Author(s):

Nieves Rodríguez-Cousiño ◽

Rosa Esteban

Keyword(s):

Wine Yeast ◽

Helper Virus ◽

Medium Size ◽

Coat Proteins ◽

Double Stranded Rna ◽

Content Type ◽

Protein Toxin ◽

Killer Toxins ◽

Helper Activity ◽

A Minor

ABSTRACT Saccharomyces cerevisiae killer strains secrete a protein toxin active on nonkiller strains of the same (or other) yeast species. Different killer toxins, K1, K2, K28, and Klus, have been described. Each toxin is encoded by a medium-size (1.5- to 2.3-kb) M double-stranded RNA (dsRNA) located in the cytoplasm. M dsRNAs require L-A helper virus for maintenance. L-A belongs to the Totiviridae family, and its dsRNA genome of 4.6 kb codes for the major capsid protein Gag and a minor Gag-Pol protein, which form the virions that separately encapsidate L-A or the M satellites. Different L-A variants exist in nature; on average, 24% of their nucleotides are different. Previously, we reported that L-A-lus was specifically associated with Mlus, suggesting coevolution, and proposed a role of the toxin-encoding M dsRNAs in the appearance of new L-A variants. Here we confirm this by analyzing the helper virus in K2 killer wine strains, which we named L-A-2. L-A-2 is required for M2 maintenance, and neither L-A nor L-A-lus shows helper activity for M2 in the same genetic background. This requirement is overcome when coat proteins are provided in large amounts by a vector or in ski mutants. The genome of another totivirus, L-BC, frequently accompanying L-A in the same cells shows a lower degree of variation than does L-A (about 10% of nucleotides are different). Although L-BC has no helper activity for M dsRNAs, distinct L-BC variants are associated with a particular killer strain. The so-called L-BC-lus (in Klus strains) and L-BC-2 (in K2 strains) are analyzed. IMPORTANCE Killer strains of S. cerevisiae secrete protein toxins that kill nonkiller yeasts. The “killer phenomenon” depends on two dsRNA viruses: L-A and M. M encodes the toxin, and L-A, the helper virus, provides the capsids for both viruses. Different killer toxins exist: K1, K2, K28, and Klus, encoded on different M viruses. Our data indicate that each M dsRNA depends on a specific helper virus; these helper viruses have nucleotide sequences that may be as much as 26% different, suggesting coevolution. In wine environments, K2 and Klus strains frequently coexist. We have previously characterized the association of Mlus and L-A-lus. Here we sequence and characterize L-A-2, the helper virus of M2, establishing the helper virus requirements of M2, which had not been completely elucidated. We also report the existence of two specific L-BC totiviruses in Klus and K2 strains with about 10% of their nucleotides different, suggesting different evolutionary histories from those of L-A viruses.

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Learning from 80 years of studies: a comprehensive catalogue of non-Saccharomyces yeasts associated with viticulture and winemaking

FEMS Yeast Research ◽

10.1093/femsyr/foab017 ◽

2021 ◽

Vol 21 (3) ◽

Author(s):

João Drumonde-Neves ◽

Ticiana Fernandes ◽

Teresa Lima ◽

Célia Pais ◽

Ricardo Franco-Duarte

Keyword(s):

Yeast Species ◽

Starter Cultures ◽

Biotechnological Applications ◽

Major Focus ◽

Wine Production ◽

Sampling Studies ◽

Volatile Acidity ◽

Wine Sector ◽

Saccharomyces Yeast ◽

Saccharomyces Yeasts

ABSTRACT Non-Saccharomyces yeast species are nowadays recognized for their impact on wine´s chemical composition and sensorial properties. In addition, new interest has been given to the commercial exploitation of non-Saccharomyces starter cultures in the wine sector. However, over many years, these yeast species were considered sources of contamination in wine production and conservation, mainly due to the high levels of volatile acidity obtained. The present manuscript systematizes 80 years of literature describing non-Saccharomyces yeast species isolated from grapes and/or grape musts. A link between each reference, the accepted taxonomic name of each species and their geographical occurrence is presented, compiling information for 293 species, in a total of 231 citations. One major focus of this work relates to the isolation of non-Saccharomyces yeasts from grapevines usually ignored in most sampling studies, also as isolation from damaged grapes. These particular niches are sources of specific yeast species, which are not identified in most other explored environments. These yeasts have high potential to be explored for important and diversified biotechnological applications.

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One-Step Multiplex PCR Assay for Differentiating Proposed New Species “Clostridium neonatale” from Closely Related Species

Journal of Clinical Microbiology ◽

10.1128/jcm.01404-15 ◽

2015 ◽

Vol 53 (11) ◽

pp. 3621-3623 ◽

Cited By ~ 5

Author(s):

Laurent Ferraris ◽

Sophia Schönherr ◽

Philippe Bouvet ◽

Brunhilde Dauphin ◽

Michel Popoff ◽

...

Keyword(s):

New Species ◽

Sensu Stricto ◽

Preterm Neonates ◽

Content Type ◽

Colony Pcr ◽

Multiplex Pcr Assay ◽

Colonization Frequency ◽

Content Identification ◽

One Step ◽

Neonatal Necrotizing Enterocolitis

“Clostridium neonatale” sp. nov., previously involved in an outbreak of neonatal necrotizing enterocolitis, was recently proposed as a new species of theClostridiumgenussensu stricto. We developed a one-step multiplex colony PCR forC. neonataleidentification and investigatedC. neonataleintestinal colonization frequency in healthy preterm neonates.

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