Interaction between flocculent and nonflocculent cells of Saccharomyces cerevisiae

1992 ◽  
Vol 38 (9) ◽  
pp. 969-974 ◽  
Author(s):  
Eduardo V. Soares ◽  
José A. Teixeira ◽  
Manuel Mota
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Key Words ◽  
Microscopic Observation ◽  
Cell Interaction ◽  
Growth Conditions ◽  
Key Words Yeast ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Cell

Interaction between nonflocculent and flocculent cells of Saccharomyces cerevisiae was studied. Adhesion experiments were done using three types of nonflocculent cells and a flocculent one. Two types of nonflocculent cells were obtained from the flocculent strain by changing environmental growth conditions. The integration of nonflocculent cells in the flocs was observed by two different methods: measurement of the sedimentation capacity of mixtures and microscopic observation of stained nonflocculent cells blended with flocculent cells. It was possible to verify that cell–cell interaction corresponds to a true stable binding and not to a simple entrapment inside the floe matrix. Key words: yeast, Saccharomyces cerevisiae, flocculation, adhesion.

scholarly journals Loss of the Homotypic Fusion and Vacuole Protein Sorting or Golgi-Associated Retrograde Protein Vesicle Tethering Complexes Results in Gentamicin Sensitivity in the Yeast Saccharomyces cerevisiae

2006 ◽  
Vol 50 (2) ◽  
pp. 587-595 ◽  
Author(s):  
Mark C. Wagner ◽  
Elizabeth E. Molnar ◽  
Bruce A. Molitoris ◽  
Mark G. Goebl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Intracellular Trafficking ◽  
Protein Sorting ◽  
Growth Conditions ◽  
Yeast Saccharomyces Cerevisiae ◽  
Vesicle Tethering ◽  
Yeast Deletion Library ◽  
Texas Red ◽  
Deletion Library ◽  
Logarithmic Growth

ABSTRACT Gentamicin continues to be a primary antibiotic against gram-negative infections. Unfortunately, associated nephro- and ototoxicity limit its use. Our previous mammalian studies showed that gentamicin is trafficked to the endoplasmic reticulum in a retrograde manner and subsequently released into the cytosol. To better dissect the mechanism through which gentamicin induces toxicity, we have chosen to study its toxicity using the simple eukaryote Saccharomyces cerevisiae. A recent screen of the yeast deletion library identified multiple gentamicin-sensitive strains, many of which participate in intracellular trafficking. Our approach was to evaluate gentamicin sensitivity under logarithmic growth conditions. By quantifying growth inhibition in the presence of gentamicin, we determined that several of the sensitive strains were part of the Golgi-associated retrograde protein (GARP) and homotypic fusion and vacuole protein sorting (HOPS) complexes. Further evaluation of their other components showed that the deletion of any GARP member resulted in gentamicin-hypersensitive strains, while the deletion of other HOPS members resulted in less gentamicin sensitivity. Other genes whose deletion resulted in gentamicin hypersensitivity included ZUO1, SAC1, and NHX1. Finally, we utilized a Texas Red gentamicin conjugate to characterize gentamicin uptake and localization in both gentamicin-sensitive and -insensitive strains. These studies were consistent with our mammalian studies, suggesting that gentamicin toxicity in yeast results from alterations to intracellular trafficking pathways. The identification of genes whose absence results in gentamicin toxicity will help target specific pathways and mechanisms that contribute to gentamicin toxicity.

Motor proteins in Saccharomyces cerevisiae

1995 ◽  
Vol 73 (S1) ◽  
pp. 369-371 ◽  
Author(s):  
Susan S. Brown
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Binding Site ◽  
Key Words ◽  
Motor Proteins ◽  
Nucleotide Binding ◽  
Nucleotide Binding Site ◽  
Temperature Sensitive ◽  
Related Protein ◽  
Yeast Saccharomyces Cerevisiae

A number of myosins have been identified in yeast (Saccharomyces cerevisiae), an organism ideally suited to dissecting out their different functions. We have learned that a temperature-sensitive defect in one of these myosins (Myo2p) can be partially overcome by overexpression of a kinesin-like protein (Smy1p). This raises the possibility of the involvement of microtubules in the same function as Myo2p. However, we have been unable to demonstrate that this is the case, either using nocodazole to depolymerize microtubules or by altering the nucleotide-binding site of Smy1p. Key words: myosin, kinesin-related protein, cytoskeleton.

Localization of a 210-kDa microtubule-interacting protein in the yeast Saccharomyces cerevisiae

1992 ◽  
Vol 38 (2) ◽  
pp. 149-152 ◽  
Author(s):  
J. Hašek ◽  
J. Jochová ◽  
P. Dráber ◽  
V. Viklický ◽  
E. Streiblová
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Key Words ◽  
Budding Yeast ◽  
Yeast Saccharomyces Cerevisiae ◽  
Double Labeling ◽  
Interacting Protein ◽  
Cytoplasmic Microtubules

Using the monoclonal antibody MA-01, which recognizes a 210-kDa protein in cell-free extracts, spindle and cytoplasmic microtubules were visualized in budding yeast, Saccharomyces cerevisiae. In additional, a spot-like staining was found beneath the plasma membrane, revealing in part correlation with F-actin distribution. This pattern was common for cells of all cell-cycle stages. The interaction of the protein recognized by MA-01 with microtubules was confirmed in the double labeling with a polyclonal antitubulin antibody and by the sensitivity of intranuclear structures stained by MA-01 to the microtubule disrupting drug nocodazole. Key words: immunoblotting, immunofluorescence, microtubule-interacting protein, Saccharomyces cerevisiae.

Fluorescence study of lectinlike receptors involved in the flocculation of the yeast Saccharomyces cerevisiae

1992 ◽  
Vol 38 (5) ◽  
pp. 405-409 ◽  
Author(s):  
C. L. Masy ◽  
A. Henquinet ◽  
M. M. Mestdagh
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fluorescence Microscopy ◽  
Key Words ◽  
Fluorescent Probes ◽  
Homogeneous Distribution ◽  
Fluorescence Study ◽  
Yeast Saccharomyces Cerevisiae ◽  
Surface Receptors ◽  
Affinity Constants ◽  
Polar Distribution

Flocculation of some yeasts involves lectinlike receptors with two different patterns of inhibition by sugars: mannose sensitive (MS) and glucose-mannose sensitive (GMS). The visualization and quantification of these receptors were performed using neoglycoproteins fluorescent probes. Fluorescence microscopy showed a homogeneous distribution of surface receptors for the strain belonging to the MS group and a polar distribution for cells belonging to the GMS group. Affinity constants, estimated by fluorimetry, were shown to have different values (MS, 2.6 ± 0.7 × 105 M−1; GMS, 2 ± 1 × 106 M−1), but the number of sites was estimated to be smaller for strain NCYC 1195 which belongs to the GMS group than for strain NCYC 869 from the MS group (MS, 2.4 ± 0.2 × 107 sites/cell; GMS, 3.9 ± 0.8 × 106 sites/cell). Key words: flocculation, neoglycoproteins, Saccharomyces, lectinlike.

Flocculation of Saccharomyces cerevisiae: inhibition by sugars

1992 ◽  
Vol 38 (12) ◽  
pp. 1298-1306 ◽  
Author(s):  
C. L. Masy ◽  
A. Henquinet ◽  
M. M. Mestdagh
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Key Words ◽  
Hydroxyl Groups ◽  
Electrostatic Repulsion ◽  
Specific Interactions ◽  
Key Words Yeast ◽  
Yeast Flocculation ◽  
Nonspecific Interactions ◽  
Lectin Specificity

Flocculation is governed by the competition between electrostatic repulsion (nonspecific interactions) and polysaccharide–protein bonds (specific interactions). In our study, the inhibition of flocculation by sugars for 12 strains of Saccharomyces cerevisiae leads us to extend the classification described in the literature and to define three groups of yeasts: flocculation mannose sensitive (MS), flocculation glucose–mannose sensitive (GMS), and flocculation mannose insensitive (MI). Only the first two groups showed specific interactions between proteins and mannans. In the MI group, the sugars tested did not inhibit flocculation. To characterize the particularities of the stereochemistry of the cell-wall proteic receptors of strains belonging to the MS and GMS groups, 31 sugars were used as inhibitor probes on two representative strains. The results show that the lectin specificity of strains belonging to the GMS group is less restricted regarding C-1 and C-2 hydroxyl groups than the lectin from strains belonging to the MS group, which interacts with all of the hydroxyl groups of mannopyranose. The two groups also differ with respect to inhibition by sugars: strains belonging to the MS group are partially inhibited whereas strains of the GMS group are completely inhibited. We observed that the presence of ethanol increases sugar fixation by strains from the MS group, but not from the GMS group. Moreover, both receptors interact with disaccharides, provided the two monomers are linked by an α(1 → 4), α(1 → 3), or α(1 → 2) bond. Key words: yeast flocculation, proteic receptors, sugars, lectins.

scholarly journals Transcriptional Regulation of the Two Sterol Esterification Genes in the Yeast Saccharomyces cerevisiae

2001 ◽  
Vol 183 (17) ◽  
pp. 4950-4957 ◽  
Author(s):  
Kristen Jensen-Pergakes ◽  
Zhongmin Guo ◽  
Mara Giattina ◽  
Stephen L. Sturley ◽  
Martin Bard
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Initiation ◽  
Physiological Role ◽  
Growth Conditions ◽  
Product Inhibition ◽  
Anaerobic Growth ◽  
Primary Role ◽  
Yeast Saccharomyces Cerevisiae ◽  
Sterol Esterification

ABSTRACT Saccharomyces cerevisiae transcribes two genes,ARE1 and ARE2, that contribute disproportionately to the esterification of sterols. Are2p is the major enzyme isoform in a wild-type cell growing aerobically. This likely results from a combination of differential transcription initiation and transcript stability. By using ARE1 andARE2 promoter fusions to lacZ reporters, we demonstrated that transcriptional initiation from theARE1 promoter is significantly reduced compared to that from the ARE2 promoter. Furthermore, the half-life of the ARE2 mRNA is approximately 12 times as long as that of the ARE1 transcript. We present evidence that the primary role of the minor sterol esterification isoform encoded byARE1 is to esterify sterol intermediates, whereas the role of the ARE2 enzyme is to esterify ergosterol, the end product of the pathway. Accordingly, the ARE1promoter is upregulated in strains that accumulate ergosterol precursors. Furthermore, ARE1 and ARE2are oppositely regulated by heme. Under heme-deficient growth conditions, ARE1 was upregulated fivefold whileARE2 was down-regulated. ARE2 requires the HAP1 transcription factor for optimal expression, and both ARE genes are derepressed in arox1 (repressor of oxygen) mutant genetic background. We further report that the ARE genes are not subject to end product inhibition; neither ARE1 nor ARE2transcription is altered in an are mutant background, nor does overexpression of either ARE gene alter the response of the ARE-lacZ reporter constructs. Our observations are consistent with an important physiological role for Are1p during anaerobic growth when heme is limiting and sterol precursors may accumulate. Conversely, Are2p is optimally required during aerobiosis when ergosterol is plentiful.

scholarly journals Intraspecies cell–cell communication in yeast

2019 ◽  
Vol 19 (7) ◽  
Author(s):  
Yoko Yashiroda ◽  
Minoru Yoshida
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sexual Reproduction ◽  
Biological Process ◽  
Yeast Species ◽  
Cell Communication ◽  
Yeast Saccharomyces Cerevisiae ◽  
Aromatic Alcohols ◽  
Fundamental Biological Process ◽  
Ultimate Purpose ◽  
Cell Cell

ABSTRACT Although yeasts are unicellular microorganisms that can live independently, they can also communicate with other cells, in order to adapt to the environment. Two yeast species, the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe, engage in various kinds of intraspecies cell–cell communication using peptides and chemical molecules that they produce, constituting a sort of ‘language’. Cell–cell communication is a fundamental biological process, and its ultimate purpose is to promote survival by sexual reproduction and acquisition of nutrients from the environment. This review summarizes what is known about intraspecies cell–cell communication mediated by molecules including mating pheromones, volatile gases, aromatic alcohols and oxylipins in laboratory strains of S. cerevisiae and S. pombe.

scholarly journals The essential function of Swc4p - a protein shared by two chromatin-modifying complexes of the yeast Saccharomyces cerevisiae - resides within its N-terminal part.

2008 ◽  
Vol 55 (3) ◽  
pp. 603-612 ◽  
Author(s):  
Arkadiusz Miciałkiewicz ◽  
Anna Chełstowska
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Essential Gene ◽  
Random Mutagenesis ◽  
Growth Conditions ◽  
Histone H2a ◽  
Terminal Part ◽  
Yeast Saccharomyces Cerevisiae ◽  
Chromatin Remodeling Complexes ◽  
Essential Function

The Swc4p protein, encoded by an essential gene, is shared by two chromatin-remodeling complexes in Saccharomyces cerevisiae cells: NuA4 (nucleosome acetyltransferase of H4) and SWR1. The SWR1 complex catalyzes ATP-dependent exchange of the nucleosomal histone H2A for H2AZ (Htz1p). The activity of NuA4 is responsible mainly for the acetylation of the H4 histone but also for the acetylation of H2A and H2AZ. In this work we investigated the role of the Swc4p protein. Using random mutagenesis we isolated a collection of swc4 mutants and showed that the essential function of Swc4p resides in its N-terminal part, within the first 269 amino acids of the 476-amino acid-long protein. We also demonstrated that Swc4p is able to accommodate numerous mutations without losing its functionality under standard growth conditions. However, when swc4 mutants were exposed to methyl methanesulfonate (MMS), hydroxyurea or benomyl, severe growth deficiencies appeared, pointing to an involvement of Swc4p in many chromatin-based processes. The mutants' phenotypes did not result from an impairment of histone acetylation, as in the mutant which bears the shortest isolated variant of truncated Swc4p, the level of overall H4 acetylation was unchanged.

A Saccharomyces cerevisiae mutant defines a new locus essential for resistance to the antitumour drug bleomycin

1996 ◽  
Vol 42 (8) ◽  
pp. 835-843 ◽  
Author(s):  
Dindial Ramotar ◽  
Jean-Yves Masson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Hydrogen Peroxide ◽  
Dna Repair ◽  
Chromosomal Translocation ◽  
Normal Growth ◽  
Fold Increase ◽  
Growth Conditions ◽  
Dna Lesions ◽  
Methyl Methanesulfonate ◽  
Yeast Saccharomyces Cerevisiae

The antitumor drug bleomycin can produce a variety of lesions in the cellular DNA by a free radical dependent mechanism. To understand how these DNA lesions are repaired, bleomycin-hypersensitive mutants were isolated from the yeast Saccharomyces cerevisiae. We report here the analysis of one mutant, DRY25, that showed extreme sensitivity to bleomycin. This mutant also exhibited hypersensitivity to hydrogen peroxide and t-butyl hydroperoxide, but showed no sensitivity to other DNA-damaging agents, including γ-rays, ultraviolet light, and methyl methanesulfonate. Subsequent analysis revealed that strain DRY25 was severely deficient in the repair of bleomycin-induced DNA lesions. Under normal growth conditions, DRY25 displayed a 3-fold increase in the frequency of chromosomal translocation that was further stimulated by 5- to 15-fold when the cells were treated with either bleomycin or hydrogen peroxide, but not by methyl methanesulfonate, as compared with the wild type. Genetic analysis indicated that the mutant defect was independent of the nucleotide excision, postreplication, or recombinational DNA-repair pathways. These data suggest that one conceivable defect of DRY25 is that it lacks a protein that protects the cell against oxidative damage to DNA. A clone that fully complemented DRY25 defect was isolated and the possible roles of the complementing gene are discussed.Key words: yeast, bleomycin, DNA repair, mutations.

scholarly journals Patterns of bud-site selection in the yeast Saccharomyces cerevisiae.

1995 ◽  
Vol 129 (3) ◽  
pp. 751-765 ◽  
Author(s):  
J Chant ◽  
J R Pringle
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Time Lapse ◽  
Growth Conditions ◽  
Alpha Cells ◽  
Yeast Saccharomyces Cerevisiae ◽  
Cell Cycles ◽  
Daughter Cells ◽  
Division Site ◽  
Mother Cells ◽  
Bud Site

Cells of the yeast Saccharomyces cerevisiae select bud sites in either of two distinct spatial patterns, known as axial (expressed by a and alpha cells) and bipolar (expressed by a/alpha cells). Fluorescence, time-lapse, and scanning electron microscopy have been used to obtain more precise descriptions of these patterns. From these descriptions, we conclude that in the axial pattern, the new bud forms directly adjacent to the division site in daughter cells and directly adjacent to the immediately preceding division site (bud site) in mother cells, with little influence from earlier sites. Thus, the division site appears to be marked by a spatial signal(s) that specifies the location of the new bud site and is transient in that it only lasts from one budding event to the next. Consistent with this conclusion, starvation and refeeding of axially budding cells results in the formation of new buds at nonaxial sites. In contrast, in bipolar budding cells, both poles are specified persistently as potential bud sites, as shown by the observations that a pole remains competent for budding even after several generations of nonuse and that the poles continue to be used for budding after starvation and refeeding. It appears that the specification of the two poles as potential bud sites occurs before a daughter cell forms its first bud, as a daughter can form this bud near either pole. However, there is a bias towards use of the pole distal to the division site. The strength of this bias varies from strain to strain, is affected by growth conditions, and diminishes in successive cell cycles. The first bud that forms near the distal pole appears to form at the very tip of the cell, whereas the first bud that forms near the pole proximal to the original division site (as marked by the birth scar) is generally somewhat offset from the tip and adjacent to (or overlapping) the birth scar. Subsequent buds can form near either pole and appear almost always to be adjacent either to the birth scar or to a previous bud site. These observations suggest that the distal tip of the cell and each division site carry persistent signals that can direct the selection of a bud site in any subsequent cell cycle.

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