scholarly journals KlHsl1 is a component of glycerol response pathways in the milk yeast Kluyveromyces lactis

Microbiology ◽  
2011 ◽  
Vol 157 (5) ◽  
pp. 1509-1518 ◽  
Author(s):  
Samantha Cialfi ◽  
Daniela Uccelletti ◽  
Augusto Carducci ◽  
Micheline Wésolowski-Louvel ◽  
Patrizia Mancini ◽  
...  
Keyword(s):  
Cell Wall ◽  
Glucose Utilization ◽  
Kluyveromyces Lactis ◽  
Cell Cycle Control ◽  
Common Pathway ◽  
Phosphorylated Form ◽  
Respiratory Inhibitor ◽  
Mutant Strains ◽  
The Relationship ◽  
Membrane Cell

In Saccharomyces cerevisiae, HSL1 (NIK1) encodes a serine-threonine protein kinase involved in cell cycle control and morphogenesis. Deletion of its putative orthologue in Kluyveromyces lactis, KlHSL1, gives rise to sensitivity to the respiratory inhibitor antimycin A (AA). Resistance to AA on glucose (Rag+ phenotype) is associated with genes (RAG) required for glucose metabolism/glycolysis. To understand the relationship between RAG and KlHSL1, rag and Klhsl1Δ mutant strains were investigated. The analysis showed that all the mutants contained a phosphorylated form of Hog1 and displayed an inability to synthesize/accumulate glycerol as a compatible solute. In addition, rag mutants also showed alterations in both cell wall and membrane fatty acids. The pleiotropic defects of these strains indicate that a common pathway regulates glucose utilization and stress response mechanisms, suggesting impaired adaptation of the plasma membrane/cell wall during the respiratory–fermentative transition. KlHsl1 could be the link between these adaptive pathways and the morphogenetic checkpoint.

Enrichment of vitronectin- and fibronectin-like proteins in NaCI-adapted plant cells and evidence for their involvement in plasma membrane-cell wall adhesion

1993 ◽  
Vol 3 (5) ◽  
pp. 637-646 ◽  
Author(s):  
Jian-Kang Zhu ◽  
Jun Shi ◽  
Utpal Singh ◽  
Sarah E. Wyatt ◽  
Ray A. Bressan ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Plant Cells ◽  
Membrane Cell

Antifungal Activity Directed Toward the Cell Wall by 2-Cyclohexylidenhydrazo- 4-Phenyl-Thiazole Against Candida albicans

2019 ◽  
Vol 19 (4) ◽  
pp. 428-438 ◽  
Author(s):  
Nívea P. de Sá ◽  
Ana P. Pôssa ◽  
Pilar Perez ◽  
Jaqueline M.S. Ferreira ◽  
Nayara C. Fonseca ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antifungal Activity ◽  
Mammalian Cells ◽  
C Elegans ◽  
Buccal Epithelial Cells ◽  
Mutant Strains ◽  
Low Toxicity ◽  
High Concentrations ◽  
Mic Value

<p>Background: The increasing incidence of invasive forms of candidiasis and resistance to antifungal therapy leads us to seek new and more effective antifungal compounds. </P><P> Objective: To investigate the antifungal activity and toxicity as well as to evaluate the potential targets of 2- cyclohexylidenhydrazo-4-phenyl-thiazole (CPT) in Candida albicans. </P><P> Methods: The antifungal activity of CPT against the survival of C. albicans was investigated in Caenorhabditis elegans. Additionally, we determined the effect of CPT on the inhibition of C. albicans adhesion capacity to buccal epithelial cells (BECs), the toxicity of CPT in mammalian cells, and the potential targets of CPT in C. albicans. </P><P> Results: CPT exhibited a minimum inhibitory concentration (MIC) value of 0.4-1.9 µg/mL. Furthermore, CPT at high concentrations (>60 x MIC) showed no or low toxicity in HepG2 cells and <1% haemolysis in human erythrocytes. In addition, CPT decreased the adhesion capacity of yeasts to the BECs and prolonged the survival of C. elegans infected with C. albicans. Analysis of CPT-treated cells showed that their cell wall was thinner than that of untreated cells, especially the glucan layer. We found that there was a significantly lower quantity of 1,3-β-D-glucan present in CPT-treated cells than that in untreated cells. Assays performed on several mutant strains showed that the MIC value of CPT was high for its antifungal activity on yeasts with defective 1,3-β-glucan synthase. </P><P> Conclusion: In conclusion, CPT appears to target the cell wall of C. albicans, exhibits low toxicity in mammalian cells, and prolongs the survival of C. elegans infected with C. albicans.</p>

scholarly journals Aspergillus nidulans wetA activates spore-specific gene expression.

1991 ◽  
Vol 11 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M A Marshall ◽  
W E Timberlake
Keyword(s):  
Gene Expression ◽  
Cell Wall ◽  
Aspergillus Nidulans ◽  
Gene Activation ◽  
Regulatory Function ◽  
Specific Gene ◽  
Coding Region ◽  
Vegetative Cells ◽  
Mutant Strains ◽  
Late Stages

The Aspergillus nidulans wetA gene is required for synthesis of cell wall layers that make asexual spores (conidia) impermeable. In wetA mutant strains, conidia take up water and autolyze rather than undergoing the final stages of maturation. wetA is activated during conidiogenesis by sequential expression of the brlA and abaA regulatory genes. To determine whether wetA regulates expression of other sporulation-specific genes, its coding region was fused to a nutritionally regulated promoter that permits gene activation in vegetative cells (hyphae) under conditions that suppress conidiation. Expression of wetA in hyphae inhibited growth and caused excessive branching. It did not lead to activation of brlA or abaA but did cause accumulation of transcripts from genes that are normally expressed specifically during the late stages of conidiation and whose mRNAs are stored in mature spores. Thus, wetA directly or indirectly regulates expression of some spore-specific genes. At least one gene (wA), whose mRNA does not occur in spores but rather accumulates in the sporogenous phialide cells, was activated by wetA, suggesting that wetA may have a regulatory function in these cells as well as in spores. We propose that wetA is responsible for activating a set of genes whose products make up the final two conidial wall layers or direct their assembly and through this activity is responsible for acquisition of spore dormancy.

scholarly journals Extracellular Glycanases of Rhizobium leguminosarum Are Activated on the Cell Surface by an Exopolysaccharide-Related Component

2000 ◽  
Vol 182 (5) ◽  
pp. 1304-1312 ◽  
Author(s):  
Angeles Zorreguieta ◽  
Christine Finnie ◽  
J. Allan Downie
Keyword(s):  
Cell Wall ◽  
Agrobacterium Tumefaciens ◽  
Cell Surface ◽  
Rhizobium Leguminosarum ◽  
Plant Cell Wall ◽  
Agar Medium ◽  
Wild Type ◽  
Close Proximity ◽  
Mutant Strains ◽  
Colony Surface

ABSTRACT Rhizobium leguminosarum secretes two extracellular glycanases, PlyA and PlyB, that can degrade exopolysaccharide (EPS) and carboxymethyl cellulose (CMC), which is used as a model substrate of plant cell wall cellulose polymers. When grown on agar medium, CMC degradation occurred only directly below colonies of R. leguminosarum, suggesting that the enzymes remain attached to the bacteria. Unexpectedly, when a PlyA-PlyB-secreting colony was grown in close proximity to mutants unable to produce or secrete PlyA and PlyB, CMC degradation occurred below that part of the mutant colonies closest to the wild type. There was no CMC degradation in the region between the colonies. By growing PlyB-secreting colonies on a lawn of CMC-nondegrading mutants, we could observe a halo of CMC degradation around the colony. Using various mutant strains, we demonstrate that PlyB diffuses beyond the edge of the colony but does not degrade CMC unless it is in contact with the appropriate colony surface. PlyA appears to remain attached to the cells since no such diffusion of PlyA activity was observed. EPS defective mutants could secrete both PlyA and PlyB, but these enzymes were inactive unless they came into contact with an EPS+ strain, indicating that EPS is required for activation of PlyA and PlyB. However, we were unable to activate CMC degradation with a crude EPS fraction, indicating that activation of CMC degradation may require an intermediate in EPS biosynthesis. Transfer of PlyB to Agrobacterium tumefaciens enabled it to degrade CMC, but this was only observed if it was grown on a lawn ofR. leguminosarum. This indicates that the surface ofA. tumefaciens is inappropriate to activate CMC degradation by PlyB. Analysis of CMC degradation by other rhizobia suggests that activation of secreted glycanases by surface components may occur in other species.

Transport of 2-deoxy-D-glucose by isolated protoplasts of the yeast, Kluyveromyces lactis

1982 ◽  
Vol 28 (7) ◽  
pp. 901-906 ◽  
Author(s):  
Paulette W. Royt ◽  
Averett S. Tombes
Keyword(s):  
Glucose Utilization ◽  
Kluyveromyces Lactis ◽  
Isolated Protoplasts ◽  
Osmotic Stabilizer ◽  
Glucose Carrier

Protoplasts of succinate- and glucose-grown Kluyveromyces lactis were generated by incubating cells with β-mercaptoethanol and β-glucuronidase in the presence of MgSO4 as osmotic stabilizer. Transport of 2-deoxyglucose by the protoplasts was comparable with that of the walled cells. Only protoplasts of succinate-grown cells exhibited a lag in glucose utilization. Removal of the wall by this technique does not result in loss of the inducible component of the glucose carrier via degradation or release.

Diminution of insulin effect by growth hormone in hypophysectomized dogs; studies with C14 glucose

1959 ◽  
Vol 196 (2) ◽  
pp. 231-234 ◽  
Author(s):  
N. Altszuler ◽  
R. Steele ◽  
A. Dunn ◽  
J. S. Wall ◽  
R. C. de Bodo
Keyword(s):  
Growth Hormone ◽  
Intravenous Injection ◽  
Glucose Utilization ◽  
Normal Animal ◽  
Glucose Production ◽  
Insulin Injection ◽  
Glucose Turnover ◽  
Insulin Effect ◽  
Relationship Of ◽  
The Relationship

The mechanism whereby growth hormone diminishes the hypoglycemic effect of insulin was investigated in hypophysectomized dogs using a C14 glucose dilution technique. An intravenous injection of insulin into the normal dog increased the rate of glucose utilization, and the resulting hypoglycemia was promptly abolished by an increased rate of glucose production. In the hypophysectomized dog prior to growth hormone administration, the insulin injection increased the rate of glucose utilization to a greater extent than in the normal animal, while the ability to increase the rate of glucose production was shown to be limited. In the hypophysectomized dog, a growth hormone regimen (1 mg/kg/day for 4 days) increased the rate of glucose production and utilization. The intravenous injection of insulin during the growth hormone regimen resulted in a lesser increase in the rate of plasma glucose utilization than observed prior to the growth hormone regimen. Furthermore, the growth hormone regimen improved the animal's limited ability to increase glucose production in response to the insulin-induced hypoglycemia. These effects of growth hormone contribute to the decreased effectiveness of insulin. The relationship of the ‘anti-insulin’ effect of growth hormone to its influence on glucose turnover is discussed.

Sensitivity of normal and mutant strains of Escherichia coli to actinomycin-D

1972 ◽  
Vol 18 (6) ◽  
pp. 909-915 ◽  
Author(s):  
A. P. Singh ◽  
K.-J. Cheng ◽  
J. W. Costerton ◽  
E. S. Idziak ◽  
J. M. Ingram
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Wild Type Strain ◽  
Actinomycin D ◽  
Cytoplasmic Membrane ◽  
Cell Envelope ◽  
Coli Strain ◽  
Wild Type ◽  
Mutant Strains ◽  
In The Wild

The site of the cell barrier to actinomycin-D uptake was studied using a wild-type Escherichia coli strain P and its cell envelope-defective filamentous mutants, strains 6γ and 12γ, both of which 'leak' β-galactosidase and alkaline phosphatase into the medium during growth indicating both membrane and cell-wall defects. Actinomycin-D entered the cells of these two mutant strains as evidenced by the inhibition of both 14C-uracil incorporation and synthesis of the induced β-galactosidase system. Under similar conditions, no inhibition occurred in the wild-type strain and its sucrose-lysozyme prepared spheroplasts. Actinomycin-D did, however, inhibit the above-mentioned systems in the wild-type sucrose-lysozyme spheroplasts prepared in the presence of 2 mM EDTA. The experimental data indicate that although the cell wall may act as a primary barrier or sieve to actinomycin-D, the cytoplasmic membrane should be considered the final and determinative barrier to this antibiotic.

Effect of perfusate glucose concentration on rat lung glycolysis.

1979 ◽  
Vol 236 (3) ◽  
pp. E229 ◽  
Author(s):  
J S Kerr ◽  
N J Baker ◽  
D J Bassett ◽  
A B Fisher
Keyword(s):  
Glucose Concentration ◽  
Glucose Utilization ◽  
Glycogen Content ◽  
Lactate Production ◽  
Bicarbonate Buffer ◽  
Exogenous Glucose ◽  
Low Glucose ◽  
The Difference ◽  
Endogenous Substrates ◽  
The Relationship

We investigated the relationship between perfusate concentration of glucose and its utilization and lactate production derived from exogenous glucose and from metabolism of endogenous substrates. Isolated rat lungs were ventilated with 5% CO2 in air and perfused for 100 min with Krebs-Ringer bicarbonate buffer containing 3% bovine serum albumin, 10(-2) U/ml insulin, [U-14C]glucose and [5-3H]glucose. Glucose utilization, total lactate production, [14C]lactate production, and 3H2O production were measured. The apparent Km and Vmax for glucose utilization were 3.4 mM and 72.5 mumol/g dry wt per h, respectively. Lactate production from endogenous substrates, calculated as the difference between total and [14C]lactate, was 37.6 +/- 2.2 mumol/g dry wt (n = 36); it was unaffected by perfusate glucose concentration and by omission of insulin, but increased threefold with anoxia. Lactate production from 1.5 mM glucose was significantly less (P less than 0.02) with insulin omitted. Glycogen content was unchanged during perfusion without glucose. These results suggest that: 1) protein catabolism contributes to lung lactate production; 2) glucose utilization by lung is not maximal at resting physiological glucose concentrations; and 3) insulin is required at low glucose concentrations for maximal glycolytic rates.

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