EFFECT OF ALKYL BENZENE SULPHONATE ON YEAST METABOLISM

1963 ◽  
Vol 9 (1) ◽  
pp. 117-127
Author(s):  
E. R. Blakley
Keyword(s):  
Cell Wall ◽  
Candida Utilis ◽  
Complete Inhibition ◽  
Enzymatic Reactions ◽  
Alkyl Benzene ◽  
Intact Cells ◽  
Yeast Metabolism ◽  
Ph Values ◽  
Upper Limit ◽  
Yeast Protoplasts

The rate of fermentation of glucose by suspensions of Candida utilis at acid pH values is reduced by alkyl benzene sulphonate in the range 75 to 250 γ/ml. Concentrations of alkyl benzene sulphonate below 75 γ/ml decrease the rate of fermentation of glucose above pH 7 and respiration at all pH values. An upper limit of 70 to 90% inhibition of fermentation or respiration is obtained at concentrations of alkyl benzene sulphonate above 250 γ/ml, except at pH 4.2 where complete inhibition is obtained. The effect of alkyl benzene sulphonate on the fermentation of glucose by yeast protoplasts is similar to the effect observed for intact yeasts. Some enzymatic reactions of cell-free extracts are inhibited by concentrations of alkyl benzene sulphonate lower than that required to affect fermentation by intact cells. The enzyme components of the cell-free preparation appear to vary in their sensitivity to the surfactant. The results support the view that the surfactant in the micellar form disrupts the cell wall of the yeast, and unassociated molecules inactivate some enzymes vital for the metabolism of the cell.

scholarly journals THE LYSIS OF GROUP A HEMOLYTIC STREPTOCOCCI BY EXTRACELLULAR ENZYMES OF STREPTOMYCES ALBUS

1952 ◽  
Vol 96 (6) ◽  
pp. 569-580 ◽  
Author(s):  
Maclyn McCarty
Keyword(s):  
Cell Wall ◽  
Extracellular Enzymes ◽  
Group A Streptococci ◽  
Carbohydrate Component ◽  
Streptococcal Cell Wall ◽  
Intact Cells ◽  
Enzymatic Lysis ◽  
Streptomyces Albus ◽  
Group A ◽  
Isolated Cell

Cell wall preparations of uniform chemical constitution have been obtained from several strains of group A streptococci. The isolated cell walls are dissolved by the same fractions of the Streptomyces albus enzymes that are effective in the lysis of intact cells, and it is likely that enzymatic lysis of group A streptococci is effected by an attack on the cell wall. The streptococcal cell wall, as prepared in this study, consists of approximately two-thirds carbohydrate and one-third protein. Small amounts of other components may be present. The carbohydrate component, which is composed primarily of N-acetyl-glucosamine and rhamnose, is the group-specific C carbohydrate. The evidence indicates that one of the streptomyces enzymes is directed toward the carbohydrate component of the cell wall.

scholarly journals Ionic Relations of Cells of Ohara Australis I. Ion Exchange in the Cell Wall

1959 ◽  
Vol 12 (4) ◽  
pp. 395 ◽  
Author(s):  
J Dainty ◽  
AB Hope
Keyword(s):  
Cell Wall ◽  
Ion Exchange ◽  
Free Space ◽  
Cell Walls ◽  
Plant Cells ◽  
External Solution ◽  
Exchangeable Cations ◽  
Intact Cells ◽  
Donnan Free Space ◽  
Isolated Cell

Measurements of ion exchange were made between isolated cell walls of Ohara australis and an external solution. Comparison between intact cells and cell walls showed that nearly all the easily exchangeable cations are located in the cell wall. The wall is hown to consist of "water free space" (W.F.S.) and "Donnan free space" (D.F.S.); the concentration of in diffusible anions in the D.F.S. is about O� 6 equivjl. This finding is contrary to past suggestions that the D.F.S. is in the cytoplasm of plant cells.

Some Functional Properties of Succinylated Single Cell Protein Concentrate

1975 ◽  
Vol 38 (9) ◽  
pp. 521-526 ◽  
Author(s):  
M. D. McELWAIN ◽  
T. RICHARDSON ◽  
C. H. AMUNDSON
Keyword(s):  
Single Cell ◽  
Candida Utilis ◽  
Corn Oil ◽  
Single Cell Protein ◽  
Cell Protein ◽  
Nucleic Acid Content ◽  
Protein Concentrate ◽  
Optimum Conditions ◽  
Ph Values ◽  
Whole Egg

Single cell protein concentrate was prepared by extracting dried Candida utilis with 0.2 N NaOH at 95 C for 10 min. The soluble protein was precipitated at pH 3.5, washed, and lyophilized. Portions of the protein isolates were succinylated so that 84% of the free amino groups were blocked. Alkaline extractions under optimum conditions gave a yield of 25 to 30% of total solids. Nucleic acid content of the isolates was 10.4% whereas protein comprised 67.3%. Succinylated (SI) and nonsuccinylated (NSI) single cell protein concentrate exhibited similar solubilities above pH 4, the apparent isoelectric point. At pH values below 4, SI was quite insoluble whereas NSI was very soluble at pH 2. Digestibilities as measured by percentage of lysine released from the protein by pepsin and pancreatin were 32.7%, 18.6%, and 3.3% for NSI, whole egg, and SI, respectively. Stabilities of emulsions prepared from corn oil (20–50%) tended to be lower when gelatin was used at the 1% level compared to NSI and SI. However, higher levels of gelatin tended to yield more stable emulsions compared to NSI and SI. Stabilities of emulsions prepared from NSI and SI tended to be comparable with NSI being slightly better. Viscosities of emulsions increased with increasing oil content and increasing emulsifier concentration.

scholarly journals The link between yeast cell wall porosity and plasma membrane permeability after PEF treatment

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Arunas Stirke ◽  
Raimonda Celiesiute-Germaniene ◽  
Aurelijus Zimkus ◽  
Nerija Zurauskiene ◽  
Povilas Simonis ◽  
...  
Keyword(s):  
Cell Wall ◽  
Yeast Cell ◽  
Recovery Process ◽  
Plasma Membrane Permeability ◽  
Intact Cells ◽  
Sytox Green ◽  
Membrane Resealing ◽  
Nucleic Acid Stain ◽  
Main Barrier ◽  
Non Equilibrium

Abstract An investigation of the yeast cell resealing process was performed by studying the absorption of the tetraphenylphosphonium (TPP+) ion by the yeast Saccharomyces cerevisiae. It was shown that the main barrier for the uptake of such TPP+ ions is the cell wall. An increased rate of TPP+ absorption after treatment of such cells with a pulsed electric field (PEF) was observed only in intact cells, but not in spheroplasts. The investigation of the uptake of TPP+ in PEF treated cells exposed to TPP+ for different time intervals also showed the dependence of the absorption rate on the PEF strength. The modelling of the TPP+ uptake recovery has also shown that the characteristic decay time of the non-equilibrium (PEF induced) pores was approximately a few tens of seconds and this did not depend on the PEF strength. A further investigation of such cell membrane recovery process using a florescent SYTOX Green nucleic acid stain dye also showed that such membrane resealing takes place over a time that is like that occurring in the cell wall. It was thus concluded that the similar characteristic lifetimes of the non-equilibrium pores in the cell wall and membrane after exposure  to  PEF indicate a strong coupling between these parts of the cell.

Purification of an exo-1,3-β-glucanase from Candida utilis

1976 ◽  
Vol 54 (11) ◽  
pp. 927-934 ◽  
Author(s):  
T. G. Villa ◽  
V. Notario ◽  
T. Benítez ◽  
J. R. Villanueva
Keyword(s):  
Amino Acids ◽  
Heavy Metal ◽  
Cell Wall ◽  
Heavy Metal Ions ◽  
Candida Utilis ◽  
Negative Charge ◽  
Hydrolysis Product ◽  
Culture Fluid ◽  
Biochemical Properties ◽  
Acidic Amino Acids

An exo-1,3-β-glucanase (EC 3.2.1.—) has been purified from the culture fluid of the yeast Candida utilis, and its biochemical properties have been studied. The amino acid analysis revealed a high content of acidic amino acids. The purified enzyme had 20% carbohydrate and a net negative charge showing higher affinity for laminarin than for p-nitrophenyl-β-D-glucopyranoside and yeast cell-wall 1,3-β-glucans. In addition, the enzyme hydrolyzed the substrates starting from the nonreducing ends, releasing glucose as the exclusive hydrolysis product. The enzyme activity was strongly inhibited by lactones and also by some heavy-metal ions.

scholarly journals Flagellar adhesion in chlamydomonas induces synthesis of two high molecular weight cell surface proteins

1983 ◽  
Vol 96 (3) ◽  
pp. 589-597 ◽  
Author(s):  
WJ Snell ◽  
A Clausell ◽  
WS Moore
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Adhesion Molecules ◽  
Mating Type ◽  
Surface Proteins ◽  
Cell Wall Proteins ◽  
Intact Cells ◽  
Mating Reaction ◽  
Ionic Detergent ◽  
Flagellar Proteins

Because our previous studies (Snell, W.J., and W.S. Moore, 1980, J. Cell Biol. 84:203- 210) on the mating reaction of chlamydomonas reinhardtii showed that there was an adhesion-induced turnover of proteins whose synthesis is induced during aggregation. Analysis by SDS PAGE and autoradiography showed that proteins of 220,000 M(r) and 165, 000 M(r) (designated A(1) and A(2) respectively) consistently showed a high rate of synthesis only in flagella or flagellar membrane-enriched fractions prepared from aggregating gametes. Since the two proteins were soluble in the non-ionic detergent NP-40 and were removed from intact cells by a brief pronase treatment, it is likely that A(1) and A(2) are membrane proteins expose on the cell surface. A(1) and A(2) were each synthesized by gametes of both mating types (mt(-) and mt(+)) and synthesis of these two proteins could be detected in the normal mating reaction (wild type mt(-) and mt(+)), in mixtures of mt(-) and impotent mt(+) gametes (which could aggregate but not fuse), and in mixtures of gametes of a single mating type with isolated flagella of the opposite mating type. Cells aggregating in tunicamycin, an inhibitor of protein glycosylation, lost their adhesiveness during aggregation and did not synthesize the 220,000 M(r) protein but instead produced a protein (possibly an underglycosylated form of A(1)) of slightly lower mol wt. The 220,000 and 165,000 M(R) proteins appeared to be flagellar proteins and not cell wall proteins because A(1) and A(2) did not co-migrate with previously identified cell wall proteins, and synthesis of the two proteins could not be detected in flagella-less (bald-2) mutant cells. Analysis of the adhesive activity of sucrose gradient fraction of detergent (octyl glucoside)-solubilized flagellar membranes revealed that fractions containing A(1) and A(2) did not have detectable adhesive activity. The possibility remains that A(1) and A(2) are adhesion molecules whose activity could not be measured in the assay we used. Alternatively, the 220,000 and 165,000 M(r) proteins may be inactivated adhesion molecules or else they may be flagellar surface proteins involved only indirectly in the adhesion process.

scholarly journals Energetics of Helicobacter pylori and Its Implications for the Mechanism of Urease-Dependent Acid Tolerance at pH 1

2002 ◽  
Vol 184 (11) ◽  
pp. 3053-3060 ◽  
Author(s):  
Kerstin Stingl ◽  
Eva-Maria Uhlemann ◽  
Roland Schmid ◽  
Karlheinz Altendorf ◽  
Evert P. Bakker
Keyword(s):  
Helicobacter Pylori ◽  
Membrane Potential ◽  
Urease Activity ◽  
Cytoplasmic Ph ◽  
Ph Homeostasis ◽  
Intact Cells ◽  
Ph Values ◽  
Cell Extracts ◽  
H Pylori ◽  
External Ph

ABSTRACT In the presence of urea the neutrophilic human pathogen Helicobacter pylori survives for several hours at pH 1 with concomitant cytoplasmic pH homeostasis. To study this effect in detail, the transmembrane proton motive force and cytoplasmic urease activity of H. pylori were determined at various pH values. In the absence of urea, the organism maintained a close-to-neutral cytoplasm and an internally negative membrane potential at external pH values greater than 4 to 5. In the presence of urea, H. pylori accomplished cytoplasmic pH homeostasis down to an external pH of 1.2. At this external pH, the cytoplasmic pH was 4.9 and the membrane potential was slightly negative inside. The latter finding is in contrast to the situation in acidophiles, which develop inside-positive membrane potentials under similar conditions. Measurements of the time course of the membrane potential confirmed that addition of urea to the cells led to hyperpolarization. Most likely, this effect was due to electrogenic export of ammonium cations from the cytoplasm. The urease activity of intact cells increased nearly exponentially with decreasing external pH. This activation was not due to enhanced gene expression at low external pH values. In cell extracts the pH optimum of urease activity was dependent on the buffer system and was about pH 5 in sodium citrate buffer. Since this is the cytoplasmic pH of the cells at pH 1 to 2, we propose that cytoplasmic pH is a factor in the in vivo activation of the urease at low external pH values. The mechanism by which urease activity leads to cytoplasmic pH homeostasis in H. pylori is discussed.

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