scholarly journals The Species-Specific Acquisition and Diversification of a K1-like Family of Killer Toxins in Budding Yeasts of the Saccharomycotina

PLoS Genetics ◽  
2021 ◽  
Vol 17 (2) ◽  
pp. e1009341 ◽  
Author(s):  
Lance R. Fredericks ◽  
Mark D. Lee ◽  
Angela M. Crabtree ◽  
Josephine M. Boyer ◽  
Emily A. Kizer ◽  
...  
Keyword(s):  
Yeast Species ◽  
Killer Toxin ◽  
Biologically Active ◽  
Genetic Sequencing ◽  
Evolutionary Origins ◽  
Killer Toxins ◽  
Antifungal Proteins ◽  
Dsrna Viruses ◽  
Niche Competition ◽  
Species Specific

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.

scholarly journals The Species-specific Acquisition and Diversification of a Novel Family of Killer Toxins in Budding Yeasts of the Saccharomycotina

2020 ◽  
Author(s):  
Lance R. Fredericks ◽  
Mark D. Lee ◽  
Angela M. Crabtree ◽  
Josephine M. Boyer ◽  
Emily A. Kizer ◽  
...  
Keyword(s):  
Yeast Species ◽  
Killer Toxin ◽  
Biologically Active ◽  
Yeast Genome ◽  
Genetic Sequencing ◽  
Evolutionary Origins ◽  
New Family ◽  
Killer Toxins ◽  
Niche Competition ◽  
Species Specific

AbstractKiller 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 the se 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 novel 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 yeast genome. The sporadic distribution of these genes supports their acquisition by horizontal gene transfer followed by diversification, with evidence of gene amplification and positive natural selection. 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 new family of biologically active killer toxins. The phylogenetic relationship between K1L and its homologs suggests gene flow via dsRNAs and DNAs across taxonomic divisions to enable the acquisition of a diverse arsenal of killer toxins for use in niche competition.

The ecological role of killer yeasts in natural communities of yeasts

1987 ◽  
Vol 33 (9) ◽  
pp. 783-796 ◽  
Author(s):  
William T. Starmer ◽  
Philip F. Ganter ◽  
Virginia Aberdeen ◽  
Marc-Andre Lachance ◽  
Herman J. Phaff
Keyword(s):  
Yeast Species ◽  
Kluyveromyces Lactis ◽  
Killer Toxin ◽  
Toxin Production ◽  
Killer Activity ◽  
Killer Yeast ◽  
Killer Toxins ◽  
Naturally Occurring ◽  
Pichia Kluyveri

The killer phenomenon of yeasts was investigated in naturally occurring yeast communities. Yeast species from communities associated with the decaying stems and fruits of cactus and the slime fluxes of trees were studied for production of killer toxins and sensitivity to killer toxins produced by other yeasts. Yeasts found in decaying fruits showed the highest incidence of killing activity (30/112), while yeasts isolated from cactus necroses and tree fluxes showed lower activity (70/699 and 11/140, respectively). Cross-reaction studies indicated that few killer-sensitive interactions occur within the same habitat at a particular time and locality, but that killer-sensitive reactions occur more frequently among yeasts from different localities and habitats. The conditions that should be optimal for killer activity were found in fruits and young rots of Opuntia cladodes where the pH is low. The fruit habitat appears to favor the establishment of killer species. Killer toxin may affect the natural distribution of the killer yeast Pichia kluyveri and the sensitive yeast Cryptococcus cereanus. Their distributions indicate that the toxin produced by P. kluyveri limits the occurrence of Cr. cereanus in fruit and Opuntia pads. In general most communities have only one killer species. Sensitive strains are more widespread than killer strains and few species appear to be immune to all toxins. Genetic study of the killer yeast P. kluyveri indicates that the mode of inheritance of killer toxin production is nuclear and not cytoplasmic as is found in Saccharomyces cerevisiae and Kluyveromyces lactis.

Antifungal Proteins from Plant Latex

2020 ◽  
Vol 21 (5) ◽  
pp. 497-506
Author(s):  
Mayck Silva Barbosa ◽  
Bruna da Silva Souza ◽  
Ana Clara Silva Sales ◽  
Jhoana D’arc Lopes de Sousa ◽  
Francisca Dayane Soares da Silva ◽  
...  
Keyword(s):  
Cell Walls ◽  
Defense Mechanisms ◽  
Hydrolytic Enzymes ◽  
Fungal Species ◽  
Biologically Active ◽  
Protein Classification ◽  
Fungal Cell ◽  
Antifungal Proteins ◽  
Plant Latex

Latex, a milky fluid found in several plants, is widely used for many purposes, and its proteins have been investigated by researchers. Many studies have shown that latex produced by some plant species is a natural source of biologically active compounds, and many of the hydrolytic enzymes are related to health benefits. Research on the characterization and industrial and pharmaceutical utility of latex has progressed in recent years. Latex proteins are associated with plants’ defense mechanisms, against attacks by fungi. In this respect, there are several biotechnological applications of antifungal proteins. Some findings reveal that antifungal proteins inhibit fungi by interrupting the synthesis of fungal cell walls or rupturing the membrane. Moreover, both phytopathogenic and clinical fungal strains are susceptible to latex proteins. The present review describes some important features of proteins isolated from plant latex which presented in vitro antifungal activities: protein classification, function, molecular weight, isoelectric point, as well as the fungal species that are inhibited by them. We also discuss their mechanisms of action.

scholarly journals Nucleofection Efficiency of Sheep Primary Fibroblasts Established from Refrigerated Skin

2018 ◽  
Vol 10 (4) ◽  
pp. 12
Author(s):  
Mahipal Singh ◽  
Xiaoling Ma
Keyword(s):  
Fluorescent Protein ◽  
Transfection Efficiency ◽  
Genetically Engineered ◽  
Dermal Fibroblasts ◽  
Biologically Active ◽  
Cell Type ◽  
Gfp Expression ◽  
Primary Fibroblasts ◽  
Species Specific ◽  
Green Fluorescent

Dermal fibroblasts are useful for production of genetically engineered biologically active factors for development of cellular therapies and tissue engineering products for regenerative medicine. However, their transfection efficiencies using traditional non-viral methods are low and vary based on cell-type and species-specific differences. Using nucleofection technology, here we show that the transfection efficiency of primary fibroblasts established after 0-, 35-, and 65-days of postmortem storage of sheep skin tissues in a refrigerator was 59.49 % ± 9.66 %, 59.33 % ± 11.59 %, and 43.48 % ± 8.09 % respectively, as determined by analysis of green fluorescent protein (GFP) expression. 

Interaction between killer strains of Hansenula anomala var. anomala and Saccharomyces cerevisiae yeast species

1985 ◽  
Vol 31 (3) ◽  
pp. 300-302 ◽  
Author(s):  
Gianfranco Rosini
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Species ◽  
Killer Toxin ◽  
Cross Reaction ◽  
Killing Activity ◽  
Hansenula Anomala ◽  
The Cross

The cross-reaction between 6 killer strains of Saccharomyces cerevisiae and 41 killer strains of Hansenula anomala var. anomala was examined. Fifteen strains of Hansenula killed one or more cultures of S. cerevisiae. None of the killer strains of H. anomala var. anomala was killed by S. cerevisiae killer strains or by killer strains of the same species. In S. cerevisiae different killer toxin and immunity systems were represented. Intraspecific killing activity was not found among the 41 strains of H. anomala var. anomala.

scholarly journals Identification and susceptibility of clinical isolates of Candida spp. to killer toxins

2018 ◽  
Vol 78 (4) ◽  
pp. 742-749
Author(s):  
E. Robledo-Leal ◽  
L. G. Rivera-Morales ◽  
M. P. Sangorrín ◽  
G. M. González ◽  
G. Ramos-Alfano ◽  
...  
Keyword(s):  
Specific Pattern ◽  
Pcr Analysis ◽  
Its2 Region ◽  
Candida Spp ◽  
5.8S Rdna ◽  
Killer Toxins ◽  
Killer Yeasts ◽  
Invasive Infections ◽  
Pichia Kluyveri ◽  
Species Specific

Abstract Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an increasing problem. We analyzed 60 yeasts isolated from patients with invasive candidiasis using a PCR/RFLP strategy based on the internal transcribed spacer (ITS2) region to identify different Candida pathogenic species. PCR analysis was performed from genomic DNA with a primer pair of the ITS2-5.8S rDNA region. PCR-positive samples were characterized by RFLP. Restriction resulted in 23 isolates identified as C. albicans using AlwI, 24 isolates as C. parapsilosis using RsaI, and 13 as C. tropicalis using XmaI. Then, a group of all isolates were evaluated for their susceptibility to a panel of previously described killer yeasts, resulting in 75% being susceptible to at least one killer yeast while the remaining were not inhibited by any strain. C. albicans was the most susceptible group while C. tropicalis had the fewest inhibitions. No species-specific pattern of inhibition was obtained with this panel of killer yeasts. Metschnikowia pulcherrima, Pichia kluyveri and Wickerhamomyces anomalus were the strains that inhibited the most isolates of Candida spp.

Combat, display and ritualization in Fiddler Crabs (Ocypodidae, genus Uca )

1966 ◽  
Vol 251 (772) ◽  
pp. 459-472 ◽  
Keyword(s):  
Visual Display ◽  
Acoustic Signals ◽  
Point Of View ◽  
Fiddler Crabs ◽  
Evolutionary Origins ◽  
The Social ◽  
Serious Injury ◽  
Species Specific ◽  
Principal Elements ◽  
Major Cheliped

The principal elements of fighting and display in the genus Uca are surveyed from the point-of-view of their apparent evolutionary origins. The components include combat behaviour between males, threat postures, acoustic signals and visual displays. The latter are characterized by rhythmic motions of the large cheliped and other appendages. Combat between males is highly ritualized, with morphological and behavioural deterrents to maximum intensity. When the deterrents are effective the fights are usually without noticeable results. Although serious injury virtually never occurs, when the deterrents are inadequate the loser sometimes gives up his burrow and occasionally does not court for varying periods thereafter. Combat seems to have evolved directly from the decapod motion of grasping combined at low intensities with an appeasement element in which the major cheliped—a releaser of aggressive behaviour—is turned away from the opponent. Threat postures are primarily intention motions of fighting. Both in the burrows and occasionally on the surface stridulation and other acoustic signals are used in threat, courtship or both. Unlike combat behaviour and threat postures, visual display is species-specific. The twenty-odd elements most often occurring in both acoustic and visual display seem clearly to be derived chiefly from feeding, cleaning and threat movements, usually through the intermediary of displacement activities; sometimes the display elements apparently evolved from conflict between feeding and threat tendencies and sometimes from intention motions. Even in species with the most advanced displays, ritualization of some elements is often only partly or temporarily achieved, while the corresponding displacement motion, unaltered and uncomplicated, is frequently elicited. Parallelisms are evident between the courses of evolution in the social behaviour of fiddler crabs and vertebrates.

scholarly journals Direct comparison of clathrin-mediated endocytosis in budding and fission yeast reveals conserved and evolvable features

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Yidi Sun ◽  
Johannes Schöneberg ◽  
Xuyan Chen ◽  
Tommy Jiang ◽  
Charlotte Kaplan ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Live Cell Imaging ◽  
Cell Imaging ◽  
Yeast Species ◽  
Quantitative Comparison ◽  
Protein Abundance ◽  
Actin Assembly ◽  
Membrane Invagination ◽  
Endocytic Protein ◽  
Species Specific

Conserved proteins drive clathrin-mediated endocytosis (CME), which from yeast to humans involves a burst of actin assembly. To gain mechanistic insights into this process, we performed a side-by-side quantitative comparison of CME in two distantly related yeast species. Though endocytic protein abundance in S. pombe and S. cerevisiae is more similar than previously thought, membrane invagination speed and depth are two-fold greater in fission yeast. In both yeasts, accumulation of ~70 WASp molecules activates the Arp2/3 complex to drive membrane invagination. In contrast to budding yeast, WASp-mediated actin nucleation plays an essential role in fission yeast endocytosis. Genetics and live-cell imaging revealed core CME spatiodynamic similarities between the two yeasts, although the assembly of two zones of actin filaments is specific for fission yeast and not essential for CME. These studies identified conserved CME mechanisms and species-specific adaptations with broad implications that are expected to extend from yeast to humans.

scholarly journals A Novel Virus Discovered in the Yeast Pichia membranifaciens.

2022 ◽  
Author(s):  
Mark D Lee ◽  
Jack W Creagh ◽  
Lance R Fredericks ◽  
Angela M Crabtree ◽  
Jagsish Suresh Patel ◽  
...  
Keyword(s):  
Tertiary Structure ◽  
Yeast Species ◽  
Molecular Models ◽  
Viral Origin ◽  
Gag Protein ◽  
Pichia Membranifaciens ◽  
The Family ◽  
Dsrna Viruses ◽  
Novel Virus

Mycoviruses are widely distributed across fungi, including yeasts of the Saccharomycotina subphylum. It was recently discovered that the yeast species Pichia membranifaciens contained double stranded RNAs (dsRNAs) that were predicted to be of viral origin. The fully sequenced dsRNA is 4,578 bp in length, with RNA secondary structures similar to the packaging, replication, and frameshift signals of totiviruses of the family Totiviridae. This novel virus has been named Pichia membranifaciens virus L-A (PmV-L-A) and is related to other totiviruses previously described within the Saccharomycotina yeasts. PmV-L-A is part of a monophyletic subgroup within the I-A totiviruses, implying a common ancestry between mycoviruses isolated from the Pichiaceae and Saccharomycetaceae yeasts. Energy minimized AlphaFold2 molecular models of the PmV-L-A Gag protein revealed structural conservation with the previously solved structure of the Saccharomyces cerevisiae virus L-A (ScV-L-A) Gag protein. The predicted tertiary structure of the PmV-L-A Pol and its homologs provide details of the potential mechanism of totivirus RNA-dependent RNA polymerases (RdRps) because of structural similarities to the RdRps of mammalian dsRNA viruses. Insights into the structure, function, and evolution of totiviruses gained from yeasts is important because of their parallels with mammalian viruses and the emerging role of totiviruses in animal disease.

Killer Toxins of Yeasts: Inhibitors of Fermentation and Their Adsorption

1987 ◽  
Vol 50 (3) ◽  
pp. 234-238 ◽  
Author(s):  
FERDINAND RADLER ◽  
MANFRED SCHMITT
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Yeast Cell ◽  
Cell Walls ◽  
Killer Toxin ◽  
Yeast Cells ◽  
Toxin Concentration ◽  
Commercial Preparation ◽  
Killer Toxins ◽  
Original Amount

The killer toxin (KT 28), a glycoprotein of Saccharomyces cerevisiae strain 28, was almost completely adsorbed by bentonite, when applied at a concentration of 1 g per liter. No significant differences were found between several types of bentonite. Killer toxin KT 28 is similarly adsorbed by intact yeast cells or by a commercial preparation of yeast cell walls that has been recommended to prevent stuck fermentations. An investigation of the cell wall fractions revealed that the toxin KT 28 was mainly adsorbed by mannan, that removed the toxin completely. The alkali-soluble and the alkali-insoluble β-1,3- and β-1,6-D-glucans lowered the toxin concentration to one tenth of the original amount. The killer toxin of the type K1 of S. cerevisiae was adsorbed much better by glucans than by mannan.

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