scholarly journals Accumulation of viruslike particles in a yeast mutant lacking a mitochondrial pore protein.

1989 ◽  
Vol 9 (3) ◽  
pp. 1100-1108 ◽  
Author(s):  
M Dihanich ◽  
E van Tuinen ◽  
J D Lambris ◽  
B Marshallsay
Keyword(s):  
Carbon Sources ◽  
Lag Phase ◽  
Cytosol Fraction ◽  
Mitochondrial Porin ◽  
Mitochondrial Functions ◽  
Microsome Fraction ◽  
Simultaneous Loss ◽  
Viruslike Particles ◽  
Mutant Cells ◽  
Pore Protein

The lack of mitochondrial porin is not lethal in Saccharomyces cerevisiae, but it impairs some respiratory functions and, therefore, growth on nonfermentable carbon sources such as glycerol. However, after a lag phase porinless mutant cells adapt to growth on glycerol, accumulating large amounts of an 86-kilodalton (kDa) protein (M. Dihanich, K. Suda, and G. Schatz, EMBO J. 6:723-728, 1987) and of a 5-kilobase RNA. Immunogold labeling localized the 86 kDa-protein exclusively to the cytosol fraction, although most of it cosedimented with the microsome fraction in earlier cell fractionations. This discrepancy was resolved when the 86-kDa protein was identified as the major coat protein in viruslike particles (VLPs) which is encoded by a double-stranded RNA (L-A RNA). Elimination of VLPs in the original porinless strain by introduction of the mak10 or the mak3 mutation increased the respiratory defect and prolonged its lag phase on nonfermentable carbon sources. The fact that the simultaneous loss of VLPs and respiratory functions are the introduction of mak10 or mak3 occurred even in some porin-containing wild-type strains suggests that there is a link between VLP and mitochondrial functions.

Accumulation of viruslike particles in a yeast mutant lacking a mitochondrial pore protein

1989 ◽  
Vol 9 (3) ◽  
pp. 1100-1108
Author(s):  
M Dihanich ◽  
E van Tuinen ◽  
J D Lambris ◽  
B Marshallsay
Keyword(s):  
Carbon Sources ◽  
Lag Phase ◽  
Cytosol Fraction ◽  
Mitochondrial Porin ◽  
Mitochondrial Functions ◽  
Microsome Fraction ◽  
Simultaneous Loss ◽  
Viruslike Particles ◽  
Mutant Cells ◽  
Pore Protein

The lack of mitochondrial porin is not lethal in Saccharomyces cerevisiae, but it impairs some respiratory functions and, therefore, growth on nonfermentable carbon sources such as glycerol. However, after a lag phase porinless mutant cells adapt to growth on glycerol, accumulating large amounts of an 86-kilodalton (kDa) protein (M. Dihanich, K. Suda, and G. Schatz, EMBO J. 6:723-728, 1987) and of a 5-kilobase RNA. Immunogold labeling localized the 86 kDa-protein exclusively to the cytosol fraction, although most of it cosedimented with the microsome fraction in earlier cell fractionations. This discrepancy was resolved when the 86-kDa protein was identified as the major coat protein in viruslike particles (VLPs) which is encoded by a double-stranded RNA (L-A RNA). Elimination of VLPs in the original porinless strain by introduction of the mak10 or the mak3 mutation increased the respiratory defect and prolonged its lag phase on nonfermentable carbon sources. The fact that the simultaneous loss of VLPs and respiratory functions are the introduction of mak10 or mak3 occurred even in some porin-containing wild-type strains suggests that there is a link between VLP and mitochondrial functions.

The adaptation of bacterial cultures during the lag phase in media containing new substrates or antibacterial agents

1957 ◽  
Vol 242 (1228) ◽  
pp. 143-143 ◽  
Keyword(s):  
Adaptive Response ◽  
Liquid Culture ◽  
Antibacterial Agents ◽  
Carbon Sources ◽  
Lag Phase ◽  
Liquid Media ◽  
Bacterial Cultures ◽  
Solid Media ◽  
Mutant Cells ◽  
Selection Of

(This paper has been published in full in Proceedings B, 147, 247) Of a series of seventeen experiments in which cells of Bact. coli mutabile and Bact. coli ( K 12) were allowed to lag in media containing all the materials necessary for growth and division, but with lactose and D-arabinose or dulcitol respectively as sole carbon sources, there were eight experiments in which it was found, when samples were withdrawn at intervals during the lag phase and were plated on solid media containing the same carbon source, that the longer the cells had remained in the liquid medium the shorter was the plate lag. Since the majority of the cells in the liquid culture took part in this response it is interpreted as an adaptation involving the bulk of the population and does not represent the selection of a few mutant cells. In the other nine experiments the reduction in lag was also observed, but since the growth of the culture took place almost simultaneously with this reduction it was not possible to draw any definite conclusion from them. In another experiment involving the adaptation of Bact. coli mutabile to resist chloramphenicol, a definite adaptive response was again obtained. Similar experiments in liquid media lacking a nitrogen source or in phosphate buffer show that the adaptation of Bact. coli mutabile to lactose and to chloramphenicol and that of Bact. lactis aerogenes to D-arabinose in the presence of streptomycin can also go a considerable way in media which do not contain all the materials necessary for growth and division. Here again it is not necessary to postulate the presence of special mutant cells.

scholarly journals Nrg1 and Nrg2 Transcriptional Repressors Are Differently Regulated in Response to Carbon Source

2004 ◽  
Vol 3 (2) ◽  
pp. 311-317 ◽  
Author(s):  
Cristin D. Berkey ◽  
Valmik K. Vyas ◽  
Marian Carlson
Keyword(s):  
Carbon Source ◽  
Carbon Sources ◽  
Large Set ◽  
Transcriptional Repressors ◽  
Glucose Limitation ◽  
Dna Binding Domains ◽  
Protein Levels ◽  
Binding Domains ◽  
And Function ◽  
Mutant Cells

ABSTRACT The Nrg1 and Nrg2 repressors of Saccharomyces cerevisiae have highly similar zinc fingers and closely related functions in the regulation of glucose-repressed genes. We show that NRG1 and NRG2 are differently regulated in response to carbon source at both the RNA and protein levels. Expression of NRG1 RNA is glucose repressed, whereas NRG2 RNA levels are nearly constant. Nrg1 protein levels are elevated in response to glucose limitation or growth in nonfermentable carbon sources, whereas Nrg2 levels are diminished. Chromatin immunoprecipitation assays showed that Nrg1 and Nrg2 bind DNA both in the presence and absence of glucose. In mutant cells lacking the corepressor Ssn6(Cyc8)-Tup1, promoter-bound Nrg1, but not Nrg2, functions as an activator in a reporter assay, providing evidence that the two Nrg proteins have distinct properties. We suggest that the differences in expression and function of these two repressors, in combination with their similar DNA-binding domains, contribute to the complex regulation of the large set of glucose-repressed genes.

Biofilm formation by a biotechnologically important tropical marine yeast isolate, Yarrowia lipolytica NCIM 3589

2008 ◽  
Vol 58 (6) ◽  
pp. 1221-1229 ◽  
Author(s):  
D. H. Dusane ◽  
Y. V. Nancharaiah ◽  
V. P. Venugopalan ◽  
A. R. Kumar ◽  
S. S. Zinjarde
Keyword(s):  
Yarrowia Lipolytica ◽  
Biofilm Formation ◽  
Edible Oils ◽  
Carbon Sources ◽  
Three Dimensional ◽  
Ecological Niches ◽  
Lag Phase ◽  
Biofilm Growth ◽  
Water Media ◽  
Biofilm Development

Biofilm formation by Yarrowia lipolytica, a biotechnologically important fungus in microtitre plates, on glass slide surfaces and in flow cell was investigated. In microtitre plates, there was a short lag phase of adhesion followed by a period of rapid biofilm growth. The fungus formed extensive biofilms on glass slides, whereas in flow-cells a multicellular, three-dimensional microcolony structure was observed. The isolate formed biofilms in seawater and in fresh water media at neutral pH when grown in microtitre plates. The carbon sources differentially affected formation of biofilms in microtitre plates. Lactic acid, erythritol, glycerol, glucose and edible oils supported the formation of biofilms, while alkanes resulted in sub-optimal biofilm development. A variation in the morphology of the fungus was observed with different carbon sources. The results point to the possible existence of highly structured biofilms in varied ecological niches from where the yeast is isolated.

scholarly journals The Vacuole and Mitochondria Patch (vCLAMP) Protein Mcp1 Is Involved in Maintenance of Mitochondrial Function and Mitophagy in Candida albicans

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaolong Mao ◽  
Li Yang ◽  
Yiming Fan ◽  
Jiazhen Wang ◽  
Dongkai Cui ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Carbon Sources ◽  
Cellular Functions ◽  
Core Component ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Mitochondrial Functions ◽  
Abnormal Accumulation ◽  
Membrane Contact

The vacuole and mitochondria patches (vCLAMPs) are novel membrane contact sites in yeast. However, their role in autophagy has not been elucidated so far. In this article, the role of Mcp1, one core component of vCLAMP, in mitophagy of Candida albicans was investigated. Deletion of MCP1 led to abnormal accumulation of enlarged mitochondria and attenuated stability of mitochondrial DNA (mtDNA) in C. albicans when cultured in non-fermentable carbon sources. Furthermore, the mcp1Δ/Δ mutant exhibited defective growth and degradation of Csp37-GFP. These results indicate that Mcp1 plays a crucial role in mitophagy and maintenance of mitochondrial functions under the non-fermentable condition. Interestingly, this deletion had no impact on degradation of Atg8 (the macroautophagy reporter) and Lap41 (the cytoplasm-to-vacuole targeting pathway marker) under SD-N medium. Moreover, deletion of MCP1 inhibited filamentous growth and impaired virulence of the pathogen. This study provides an insight to vCLAMPs in cellular functions and pathogenicity in C. albicans.

scholarly journals Multiple genes are required for proper insertion of secretory proteins into the endoplasmic reticulum in yeast.

1989 ◽  
Vol 109 (6) ◽  
pp. 2641-2652 ◽  
Author(s):  
J A Rothblatt ◽  
R J Deshaies ◽  
S L Sanders ◽  
G Daum ◽  
R Schekman
Keyword(s):  
Genetic Selection ◽  
Secretory Protein ◽  
Yeast Cells ◽  
Secretory Proteins ◽  
Gene Products ◽  
Cytosol Fraction ◽  
Electrophoretic Mobilities ◽  
Precursor Molecules ◽  
Mutant Cells

Genes that function in translocation of secretory protein precursors into the ER have been identified by a genetic selection for mutant yeast cells that fail to translocate a signal peptide-cytosolic enzyme hybrid protein. The new mutants, sec62 and sec63, are thermosensitive for growth and accumulate a variety of soluble secretory and vacuolar precursors whose electrophoretic mobilities coincide with those of the corresponding in vitro translated polypeptides. Proteolytic sensitivity of precursor molecules in extracts of mutant cells confirms that polypeptide translocation is blocked. Some form of interaction among the SEC61 (Deshaies, R. J., and R. Schekman. 1987. J. Cell Biol. 105:633-645), SEC62 and SEC63 gene products is suggested by the observation that haploid cells containing any pair of the mutations are inviable at 24 degrees C and show a marked enhancement of the translocation defect. The translocation defects of two mutants (sec62 and sec63) have been reproduced in vitro. sec63 microsomes display low and thermolabile translocation activity for prepro-alpha-factor (pp alpha F) synthesized with a cytosol fraction from wild type yeast. These gene products may constitute part of the polypeptide recognition or translocation apparatus of the ER membrane. Pulse-chase analysis of the translocation-defective mutants demonstrates that insertion of pp alpha F into the ER can proceed posttranslationally.

scholarly journals INHIBITION OF THE GROWTH OF TOLERANT YEAST Saccharomyces cerevisiae STRAIN I136 BY A MIXTURE OF SYNTHETIC INHIBITORS

2017 ◽  
Vol 18 (1) ◽  
pp. 17
Author(s):  
Eny Ida Riyanti ◽  
Edy Listanto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Carbon Sources ◽  
Resistance Mechanism ◽  
Lag Phase ◽  
Cell Factory ◽  
Yeast Saccharomyces Cerevisiae ◽  
Fermentation Products ◽  
Hydroxymethyl Furfural ◽  
Cell Biomass

<p>Biomass from lignocellulosic wastes is a potential source for biobased products.  However, one of the constraints in utilization of biomass hydrolysate is the presence of inhibitors. Therefore, the use of inhibitor-tolerant microorganisms in the fermentation is required. The study aimed to investigate the effect of a mixture of inhibitors on the growth of Saccharomyces cerevisiae strain I136 grown in medium containing synthetic inhibitors (acetic acid, formic acid, furfural, 5-hydroxymethyl furfural/5-HMF, and levulinic acid) in four different concentrations with a mixture of carbon sources, glucose  (50 g.l-1) and xylose (50 g.l-1) at 30oC. The parameters related to growth and fermentation products were observed. Results showed that the strain was able to grow in media containing natural inhibitors (BSL medium) with µmax of 0.020/h. Higher level of synthetic inhibitors prolonged the lag phase, decreased the cell biomass and ethanol production, and specific growth rate. The strain could detoxify furfural and 5-HMF and produced the highest ethanol (Y(p/s) of 0.32 g.g-1) when grown in BSL. Glucose was utilized as its level decreased in a result of increase in cell biomass, in contrast to xylose which was not consumed. The highest cell biomass was produced in YNB with Y (x/s) value of 0.25 g.g-1. The strain produced acetic acid as a dominant side product and could convert furfural into a less toxic compound, hydroxyl furfural. This robust tolerant strain provides basic information on resistance mechanism and would be useful for bio-based cell factory using lignocellulosic materials. </p>

scholarly journals Carbon Source-Dependent Phosphorylation of Hexokinase PII and Its Role in the Glucose-Signaling Response in Yeast

1998 ◽  
Vol 18 (5) ◽  
pp. 2940-2948 ◽  
Author(s):  
Francisca Randez-Gil ◽  
Pascual Sanz ◽  
Karl-Dieter Entian ◽  
Jose Antonio Prieto
Keyword(s):  
Carbon Source ◽  
Glucose Repression ◽  
Carbon Sources ◽  
Glucose Signaling ◽  
Regulatory Effects ◽  
Metabolic Signal ◽  
Signal Transductions ◽  
Mutant Cells

ABSTRACT The HXK2 gene is required for a variety of regulatory effects leading to an adaptation for fermentative metabolism inSaccharomyces cerevisiae. However, the molecular basis of the specific role of Hxk2p in these effects is still unclear. One important feature in order to understand the physiological function of hexokinase PII is that it is a phosphoprotein, since protein phosphorylation is essential in most metabolic signal transductions in eukaryotic cells. Here we show that Hxk2p exists in vivo in a dimeric-monomeric equilibrium which is affected by phosphorylation. Only the monomeric form appears phosphorylated, whereas the dimer does not. The reversible phosphorylation of Hxk2p is carbon source dependent, being more extensive on poor carbon sources such as galactose, raffinose, and ethanol. In vivo dephosphorylation of Hxk2p is promoted after addition of glucose. This effect is absent in glucose repression mutants cat80/grr1, hex2/reg1, andcid1/glc7. Treatment of a glucose crude extract fromcid1-226 (glc7-T152K) mutant cells with λ-phosphatase drastically reduces the presence of phosphoprotein, suggesting that CID1/GLC7 phosphatase together with its regulatory HEX2/REG1 subunit are involved in the dephosphorylation of the Hxk2p monomer. An HXK2 mutation encoding a serine-to-alanine change at position 15 [HXK2(S15A)] was to clarify the in vivo function of the phosphorylation of hexokinase PII. In this mutant, where the Hxk2 protein is unable to undergo phosphorylation, the cells could not provide glucose repression of invertase. Glucose induction ofHXT gene expression is also affected in cells expressing the mutated enzyme. Although we cannot rule out a defect in the metabolic state of the cell as the origin of these phenomena, our results suggest that the phosphorylation of hexokinase is essential in vivo for glucose signal transduction.

scholarly journals N -Acetylglucosamine (GlcNAc)-Inducible Gene GIG2 Is a Novel Component of GlcNAc Metabolism in Candida albicans

2013 ◽  
Vol 13 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Swagata Ghosh ◽  
Kongara Hanumantha Rao ◽  
Neel Sarovar Bhavesh ◽  
Gobardhan Das ◽  
Ved Prakash Dwivedi ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Carbon Sources ◽  
Transcriptional Responses ◽  
Content Type ◽  
Metabolic Intermediates ◽  
Catabolic Genes ◽  
Opportunistic Fungal Pathogen ◽  
Targeted Inhibition ◽  
Mutant Cells ◽  
Insight Into

ABSTRACT Candida albicans is an opportunistic fungal pathogen that resides in the human body as a commensal and can turn pathogenic when the host is immunocompromised. Adaptation of C. albicans to host niche-specific conditions is important for the establishment of pathogenicity, where the ability of C. albicans to utilize multiple carbon sources provides additional flexibility. One alternative sugar is N -acetylglucosamine (GlcNAc), which is now established as an important carbon source for many pathogens and can also act as a signaling molecule. Although GlcNAc catabolism has been well studied in many pathogens, the importance of several enzymes involved in the formation of metabolic intermediates still remains elusive. In this context, microarray analysis was carried out to investigate the transcriptional responses induced by GlcNAc under different conditions. A novel gene that was highly upregulated immediately following the GlcNAc catabolic genes was identified and was named GIG2 (GlcNAc-induced gene 2). This gene is regulated in a manner distinct from that of the GlcNAc-induced genes described previously in that GlcNAc metabolism is essential for its induction. Furthermore, this gene is involved in the metabolism of N -acetylneuraminate (sialic acid), a molecule equally important for initial host-pathogen recognition. Mutant cells showed a considerable decrease in fungal burden in mouse kidneys and were hypersensitive to oxidative stress conditions. Since GIG2 is also present in many other fungal and enterobacterial genomes, targeted inhibition of its activity would offer insight into the treatment of candidiasis and other fungal or enterobacterial infections.

scholarly journals The Crabtree Effect Shapes theSaccharomyces cerevisiaeLag Phase during the Switch between Different Carbon Sources

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Gemma Perez-Samper ◽  
Bram Cerulus ◽  
Abbas Jariani ◽  
Lieselotte Vermeersch ◽  
Nuria Barrajón Simancas ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Carbon Sources ◽  
Anaerobic Growth ◽  
Lag Phase ◽  
Crabtree Effect ◽  
Molecular Processes ◽  
Content Type ◽  
A Genome ◽  
Growth Experiments ◽  
Lag Phases

ABSTRACTWhen faced with environmental changes, microbes often enter a temporary growth arrest during which they reprogram the expression of specific genes to adapt to the new conditions. A prime example of such a lag phase occurs when microbes need to switch from glucose to other, less-preferred carbon sources. Despite its industrial relevance, the genetic network that determines the duration of the lag phase has not been studied in much detail. Here, we performed a genome-wide Bar-Seq screen to identify genetic determinants of theSaccharomyces cerevisiaeglucose-to-galactose lag phase. The results show that genes involved in respiration, and specifically those encoding complexes III and IV of the electron transport chain, are needed for efficient growth resumption after the lag phase. Anaerobic growth experiments confirmed the importance of respiratory energy conversion in determining the lag phase duration. Moreover, overexpression of the central regulator of respiration,HAP4, leads to significantly shorter lag phases. Together, these results suggest that the glucose-induced repression of respiration, known as the Crabtree effect, is a major determinant of microbial fitness in fluctuating carbon environments.IMPORTANCEThe lag phase is arguably one of the prime characteristics of microbial growth. Longer lag phases result in lower competitive fitness in variable environments, and the duration of the lag phase is also important in many industrial processes where long lag phases lead to sluggish, less efficient fermentations. Despite the immense importance of the lag phase, surprisingly little is known about the exact molecular processes that determine its duration. Our study uses the molecular toolbox ofS. cerevisiaecombined with detailed growth experiments to reveal how the transition from fermentative to respirative metabolism is a key bottleneck for cells to overcome the lag phase. Together, our findings not only yield insight into the key molecular processes and genes that influence lag duration but also open routes to increase the efficiency of industrial fermentations and offer an experimental framework to study other types of lag behavior.

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