A New Wine
            <i>Saccharomyces cerevisiae</i>
            Killer Toxin (Klus), Encoded by a Double-Stranded RNA Virus, with Broad Antifungal Activity Is Evolutionarily Related to a Chromosomal Host Gene

Rodríguez-Cousiño, Nieves; Maqueda, Matilde; Ambrona, Jesús; Zamora, Emiliano; Esteban, Rosa; Ramírez, Manuel

doi:10.1128/aem.02501-10

Cited by 110 publications

(164 citation statements)

References 47 publications

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“…Killer strains of Saccharomyces cerevisiae secrete protein toxins derived from a family of double-stranded RNAs (dsRNAs). The toxins have been grouped into four types (K1, K2, K28, and Klus) based on their killing profiles and lack of crossimmunity (3,4). Such proteins are able to kill the nonkiller yeast, as well as yeast of other killer types, while the toxin-producing cells remain immune to their own or to the same type of killers (4,5).…”

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confidence: 99%

Yeast β-1,6-Glucan Is a Primary Target for the Saccharomyces cerevisiae K2 Toxin

et al. 2015

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b Certain Saccharomyces cerevisiae strains secrete different killer proteins of double-stranded-RNA origin. These proteins confer a growth advantage to their host by increasing its survival. K2 toxin affects the target cell by binding to the cell surface, disrupting the plasma membrane integrity, and inducing ion leakage. In this study, we determined that K2 toxin saturates the yeast cell surface receptors in 10 min. The apparent amount of K2 toxin, bound to a single cell of wild type yeast under saturating conditions, was estimated to be 435 to 460 molecules. It was found that an increased level of ␤-1,6-glucan directly correlates with the number of toxin molecules bound, thereby impacting the morphology and determining the fate of the yeast cell. We observed that the binding of K2 toxin to the yeast surface receptors proceeds in a similar manner as in case of the related K1 killer protein. It was demonstrated that the externally supplied pustulan, a poly-␤-1,6-glucan, but not the glucans bearing other linkage types (such as laminarin, chitin, and pullulan) efficiently inhibits the K2 toxin killing activity. In addition, the analysis of toxin binding to the intact cells and spheroplasts confirmed that majority of K2 protein molecules attach to the ␤-1,6-glucan, rather than the plasma membrane-localized receptors. Taken together, our results reveal that ␤-1,6-glucan is a primary target of K2 toxin and is important for the execution of its killing property.T he production of antimycotic killer toxins has been observed in several yeast genera and proved to be a widespread phenomenon (1, 2). Killer strains of Saccharomyces cerevisiae secrete protein toxins derived from a family of double-stranded RNAs (dsRNAs). The toxins have been grouped into four types (K1, K2, K28, and Klus) based on their killing profiles and lack of crossimmunity (3, 4). Such proteins are able to kill the nonkiller yeast, as well as yeast of other killer types, while the toxin-producing cells remain immune to their own or to the same type of killers (4, 5). K1 toxin disrupts the regulated ion flux across the plasma membrane, leading to the death of sensitive yeast strains (6, 7). The killing action of K1 toxin involves at least two steps. During the first step, the toxin binds to the cell wall, whereas the second step leads to the translocation and insertion of the toxin into the plasma membrane (6). Beta-1,6-glucan was originally proposed to be a cell wall receptor for K1 (8). Analysis of several kre mutants demonstrated that decrease of the cell wall ␤-1,6-glucan level leads to K1 resistance, thus confirming the involvement of this type of glucan in toxin binding (9). During the second step, K1 toxin interacts with plasma membrane receptors and disrupts the functional integrity of the plasma membrane either by inducing the formation of new ion channels (7) or through the activation of existing potassium channels (10). Products of TOK1 (protein, forming the potassium ion channel) and KRE1 (glycoprotein, involved in ␤-glucan assembly) have be...

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confidence: 99%

Yeast β-1,6-Glucan Is a Primary Target for the Saccharomyces cerevisiae K2 Toxin

et al. 2015

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“…The killer activity of S. cerevisiae is mainly dependent on the killer:sensitive ratio. These killer toxins have a narrow spectrum of activity, inhibiting only strains or species within the same genus (Mannazzu et al, 2002), except for the Klus killer toxin, which is active against yeasts such as Hanseniaspora spp., Kluyveromyces lactis, Candida albicans, Candida dubliniensis, Candida kefir and Candida tropicalis, and the K1, K2 and K28 killer strains of S. cerevisiae (Rodríguez-Cousin et al, 2011). Considering that these toxins are not active against B. bruxellensis they will not be discussed further in this review.…”

Section: General Considerationsmentioning

confidence: 99%

“…Killer toxins of S. cerevisiae S. cerevisiae's killer toxins were first discovered in 1963 (Woods & Bevan, 1968 (Magliani et al, 1997;Schmitt & Breinig, 2006;Rodríguez-Cousin, 2011). The killer activity of S. cerevisiae is mainly dependent on the killer:sensitive ratio.…”

Section: General Considerationsmentioning

confidence: 99%

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Non-Saccharomyces Killer Toxins: Possible Biocontrol Agents Against Brettanomyces in Wine?

Mehlomakulu

Setati

Divol

2015

SAJEV

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Red wine spoiled by the yeast Brettanomyces bruxellensis is characterised by off-odours commonly described as horse sweat, phenolic, varnish and band-aid. The growth of this yeast in wine is traditionally controlled by the use of sulphur dioxide (SO 2 ). However, the concentration of SO 2 , the pH of the wine, the presence of SO 2 -binding chemical compounds in the wine, as well as the strain of B. bruxellensis, determine the effectiveness of SO 2 . Other chemical preservatives have been tested, but are not much more efficient than SO 2 , and methods used to clean barrels are only partially effective. Filtration of wine and the use of electric currents/fields are also reported to alter the physical and sensory properties of wine. In this context, alternative methods are currently sought to achieve full control of this yeast in wine. Killer toxins have recently been proposed to fulfil this purpose. They are antimicrobial compounds secreted by Saccharomyces and non-Saccharomyces yeasts, displaying killer activity against other yeasts and filamentous fungi. They are believed to play a role in yeast population dynamics, and this killer phenotype potentially could be exploited to inhibit the growth of undesired microorganisms within a microbial ecosystem such as that occurring in wine. In this review, non-Saccharomyces killer toxins are described and their potential application in inhibiting B. bruxellensis in wine is discussed in comparison to other tried methods and techniques.

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“…A good example is the assimilation of viruses by prokaryotic cells as immunological memories [108]. However, absorbed nucleic-acids may distort the cell's behaviour [142][143][144], often making it destroy itself. In both cases, which may occur alongside, biological interactions entail organisational changes and in-formation exchange.…”

Section: Interacting Organisations: Biological and Complex Phenomenamentioning

confidence: 99%

From Systems to Organisations

Kritz

2017

Systems

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Warren Weaver, writing about the function that science should have in mankind's developing future, ideas and ideals, proposed to classify scientific problems into 'problems of simplicity', 'problems of disorganised complexity', and 'problems of organised complexity'-the huge complementary class to which all biological, human, and social problems belong. Problems of simplicity have few components and variables and have been extensively addressed in the last 400 years. Problems of disorganised complexity have a huge number of individually erratic components and variables, but possess collective regularities that can be analysed by resourcing to stochastic methods. Yet, 'problems of organised complexity' do not yield easily to classical or statistical treatment. Interrelations among phenomenon elements change during its evolution alongside commonly used state variables. This invalidates independence and additivity assumptions that support reductionism and affect behaviour and outcome. Moreover, organisation, the focal point in this complementary class, is still an elusive concept despite gigantic efforts undertaken since a century ago to tame it. This paper addresses the description, representation and study of phenomena in the 'problems of organised complexity' class, arguing that they should be treated as a collection of interacting organisations. Furthermore, grounded on relational mathematical constructs, a formal theoretical framework that provides operational definitions, schemes for representing organisations and their changes, as well as interactions of organisations is introduced. Organisations formally extend the general systems concept and suggest a novel perspective for addressing organised complexity phenomena as a collection of interacting organisations.

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A New Wine Saccharomyces cerevisiae Killer Toxin (Klus), Encoded by a Double-Stranded RNA Virus, with Broad Antifungal Activity Is Evolutionarily Related to a Chromosomal Host Gene

Cited by 110 publications

References 47 publications

Yeast β-1,6-Glucan Is a Primary Target for the Saccharomyces cerevisiae K2 Toxin

Yeast β-1,6-Glucan Is a Primary Target for the Saccharomyces cerevisiae K2 Toxin

Non-Saccharomyces Killer Toxins: Possible Biocontrol Agents Against Brettanomyces in Wine?

From Systems to Organisations

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