Glucose suppression of β-glucosidase activity in a chloramphenicol-producing strain of Streptomyces venezuelae

1982 ◽  
Vol 28 (6) ◽  
pp. 593-599 ◽  
Author(s):  
S. Chatterjee ◽  
L. C. Vining
Keyword(s):  
Amino Acids ◽  
Carbon Source ◽  
Deae Cellulose ◽  
The Other ◽  
Antibiotic Biosynthesis ◽  
Control Mechanisms ◽  
Streptomyces Venezuelae ◽  
Glucosidase Activity ◽  
Cell Extracts ◽  
Source Preferences

β-Glucosidase activity was induced in Streptomyces venezuelae during growth on cellobiose, gentiobiose, salicin, methyl β-glucoside, and p-nitrophenyl β-D-glucopyranoside. Activity in cell extracts was separated by DEAE-cellulose chromatography into two fractions differing in substrate preference. One component showed higher activity with, and was more strongly induced by, cellobiose; the other showed greater activity and inducibility with salicin. Addition of glucose to cultures severely depressed induction of β-glucosidase activity by cellobiose but not by salicin. Acetate and several amino acids inhibited induction by either substrate. The action of glucose was not reversed by cyclic AMP. Cultures of S. venezuelae using glucose, cellobiose, or a mixture of the two saccharides as their carbon source produced chloramphenicol during growth. In contrast with its effect on the induction of cellobiase activity, glucose did not suppress chloramphenicol production, indicating that the control mechanisms that establish carbon source preferences are not linked to those that regulate antibiotic biosynthesis in this organism.

Role of the carbon source in regulating chloramphenicol production by Streptomyces venezuelae: studies in batch and continuous cultures

1988 ◽  
Vol 34 (11) ◽  
pp. 1217-1223 ◽  
Author(s):  
R. K. Bhatnagar ◽  
J. L. Doull ◽  
L. C. Vining
Keyword(s):  
Carbon Source ◽  
Glucose Concentration ◽  
Specific Activity ◽  
Antibiotic Production ◽  
Enzyme Synthesis ◽  
Antibiotic Biosynthesis ◽  
Synthetase Activity ◽  
Streptomyces Venezuelae ◽  
Batch Cultures ◽  
Chemostat Cultures

Both carbon- and nitrogen-limited media that supported a biphasic pattern of growth and chloramphenicol biosynthesis were devised for batch cultures of Streptomyces venezuelae. Where onset of the idiophase was associated with nitrogen depletion, a sharp peak of arylamine synthetase activity coincided with the onset of antibiotic production. The specific activity of the enzyme was highest when the carbon source in the medium was also near depletion at the trophophase–idiophase boundary. In media providing a substantial excess of carbon source through the idiophase, the peak specific activity was reduced by 75%, although the timing of enzyme synthesis was unaltered. Morever, chemostat cultures in which the growth rate was limited by the glucose concentration in the input medium failed to show a decrease in specific production of chloramphenicol as the steady-state intracellular glucose concentration was increased. The results suggest that a form of "carbon catabolite repression" regulates synthesis of chloramphenicol biosynthetic enzymes during a trophophase–idiophase transition induced by nitrogen starvation. However, this regulatory mechanism does not establish the timing of antibiotic biosynthesis and does not function during nitrogen-sufficient growth in the presence of excess glucose.

Nutrient utilization in actinomycetes. Induction of α-glucosidases in Streptomyces venezuelae

1981 ◽  
Vol 27 (7) ◽  
pp. 639-645 ◽  
Author(s):  
S. Chatterjee ◽  
L. C. Vining
Keyword(s):  
Amino Acids ◽  
Organic Acids ◽  
Ribonucleic Acid ◽  
De Novo ◽  
Nutrient Utilization ◽  
Enzyme Synthesis ◽  
De Novo Synthesis ◽  
Streptomyces Venezuelae ◽  
Messenger Ribonucleic Acid ◽  
Glucosidase Activity

Streptomyces venezuelae contains intracellular α-glucosidases that are induced during growth on maltose, isomaltose, maltotriose, dextrin, starch, and other α-glucosides. Induction was prevented by rifampicin at 10 μg∙mL−1 and inhibited by chloramphenicol or streptomycin, indicating that de novo synthesis of messenger ribonucleic acid and protein was required. Glucose and other readily utilizable sugars did not repress induction of α-glucosidase activity whereas certain organic acids and amino acids effectively reduced enzyme synthesis. Extracts of mycelium grown in the presence of maltose as an inducer hydrolysed maltose and isomaltose rapidly. Sucrose and other α-glucosides were less suitable substrates whereas trehalose and starch were not hydrolysed. No activity was observed with β-glucosides, α-galactosides, or methyl α-mannoside.

Catabolite repression in Streptomyces venezuelae. Induction of β-galactosidase, chloramphenicol production, and intracellular cyclic adenosine 3′,5′-monophosphate concentrations

1982 ◽  
Vol 28 (3) ◽  
pp. 311-317 ◽  
Author(s):  
S. Chatterjee ◽  
L. C. Vining
Keyword(s):  
Carbon Source ◽  
Cyclic Nucleotide ◽  
Catabolite Repression ◽  
Marked Decrease ◽  
Nutrient Utilization ◽  
Sole Source ◽  
Glucose Measurement ◽  
Antibiotic Biosynthesis ◽  
Streptomyces Venezuelae ◽  
Production Pattern

Chloramphenicol production was studied in cultures of Streptomyces venezuelae growing in a simple buffered medium with ammonia as the nitrogen source and glucose, lactose, or a glucose–lactose mixture as the sole source of carbon. With each carbon source the antibiotic was formed during growth. In the glucose–lactose medium, the production pattern was biphasic; a marked decrease in the rate of synthesis was associated with depletion of glucose from the medium and a corresponding diauxie pause in growth. Cells of S. venezuelae contained an inducible β-galactosidase. Induction by lactose was suppressed by glucose. Measurement of the concentration of intracellular adenonsine 3′,5′-cyclic monophosphate during growth of cultures with glucose or a glucose–lactose mixture as the source of carbon showed no appreciable changes coinciding with depletion of glucose or the onset of chloramphenicol biosynthesis. It is concluded that the cyclic nucleotide does not mediate selective nutrient utilization or control antibiotic biosynthesis in this organism.

Characterization of an isozyme of S-adenosylmethionine synthetase from rat liver

1984 ◽  
Vol 62 (5) ◽  
pp. 276-279 ◽  
Author(s):  
C. H. Lin ◽  
W. Chung ◽  
K. P. Strickland ◽  
A. J. Hudson
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Enzymatic Synthesis ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Aromatic Amino Acids ◽  
Adenosylmethionine Synthetase ◽  
Cellulose Column

An isozyme of S-adenosylmethionine synthetase has been purified to homogeneity by ammonium sulfate fractionation, DEAE-cellulose column chromatography, and gel filtration on a Sephadex G-200 column. The purified enzyme is very unstable and has a molecular weight of 120 000 consisting of two identical subunits. Amino acid analysis on the purified enzyme showed glycine, glutamate, and aspartate to be the most abundant and the aromatic amino acids to be the least abundant. It possesses tripolyphosphatase activity which can be stimulated five to six times by S-adenosylmethionine (20–40 μM). The findings support the conclusion that an enzyme-bound tripolyphosphate is an obligatory intermediate in the enzymatic synthesis of S-adenosylmethionine from ATP and methionine.

Natural Vulcanization Accelerators in Hevea Latex

1948 ◽  
Vol 21 (4) ◽  
pp. 853-859
Author(s):  
R. F. A. Altman
Keyword(s):  
Amino Acids ◽  
Experimental Results ◽  
The Other ◽  
Active Nitrogen ◽  
Nitrogen Bases ◽  
Other Hand ◽  
Decomposition Processes ◽  
Volatile Products ◽  
Nitrogenous Substances ◽  
The One

Abstract As numerous investigators have shown, some of the nonrubber components of Hevea latex have a decided accelerating action on the process of vulcanization. A survey of the literature on this subject points to the validity of certain general facts. 1. Among the nonrubber components of latex which have been investigated, certain nitrogenous bases appear to be most important for accelerating the rate of vulcanization. 2. These nitrogen bases apparently occur partly naturally in fresh latex, and partly as the result of putrefaction, heating, and other decomposition processes. 3. The nitrogen bases naturally present in fresh latex at later stages have been identified by Altman to be trigonelline, stachhydrine, betonicine, choline, methylamine, trimethylamine, and ammonia. These bases are markedly active in vulcanization, as will be seen in the section on experimental results. 4. The nitrogenous substances formed by the decomposition processes have only partly been identified, on the one hand as tetra- and pentamethylene diamine and some amino acids, on the other hand as alkaloids, proline, diamino acids, etc. 5. It has been generally accepted that these nitrogenous substances are derived from the proteins of the latex. 6. Decomposition appears to be connected with the formation of a considerable amount of acids. 7. The production of volatile nitrogen bases as a rule accompanies the decomposition processes. These volatile products have not been identified. 8. The active nitrogen bases, either already formed or derived from complex nitrogenous substances, seem to be soluble in water but only slightly soluble in acetone.

METABOLISM OF AROMATIC COMPOUNDS IN HEALTHY AND RUST-INFECTED PRIMARY LEAVES OF WHEAT: II. STUDIES WITH L-PHENYLALANINE-U-14C, L-TYROSINE-U-14C, AND FERULATE-U-14C

1967 ◽  
Vol 45 (11) ◽  
pp. 2137-2153 ◽  
Author(s):  
A. Fuchs ◽  
R. Rohringer ◽  
D. J. Samborski
Keyword(s):  
Amino Acids ◽  
Stem Rust ◽  
Aromatic Compounds ◽  
The Other ◽  
Major Portion ◽  
Insoluble Residue ◽  
Resistant Reaction ◽  
Wheat Leaves

Wheat leaves infected with stem rust, especially those of susceptible plants, contained more phenylalanine and tyrosine than healthy leaves. The utilization of phenylalanine was increased in both the susceptible and resistant reaction, but the utilization of tyrosine was increased only in the susceptible reaction. No evidence of interconversion of these amino acids was obtained.In n-butanol extracts, which contained glycosides, many constituents were labelled after feeding of L-phenylalanine-U-14C. Most of the n-butanol extractives from resistant-reacting leaves contained more label than those from susceptible-reacting leaves or from healthy leaves. However, one of the n-butanol extractives from susceptible-reacting leaves was 5–10 times as active as that isolated from the other tissues.With L-phenylalanine-U-14C and ferulate-U-14C as precursors, more activity was recovered in insoluble than in soluble esters (of ferulate and p-coumarate). With L-tyrosine-U-14C as precursor, the reverse was observed. After infection, the proportion of label in insoluble esters increased more in resistant leaves than it did in susceptible leaves, regardless of the precursor used.A major portion of the activity from these precursors was recovered in the insoluble residue that contained protein and other polymers. In the experiment with L-phenylalanine-U-14C, this residue was fractionated into protein and non-hydrolyzable material. Susceptible-reacting leaves contained equal amounts of activity in these fractions, while resistant-reacting leaves incorporated 2.5 times as much activity into the non-hydrolyzable material as into protein.

scholarly journals Amino acid transport in normal and glutathione-deficient sheep erythrocytes

1976 ◽  
Vol 154 (1) ◽  
pp. 43-48 ◽  
Author(s):  
J D Young ◽  
J C Ellory ◽  
E M Tucker
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Cell Types ◽  
The Other ◽  
Acid Transport ◽  
Sheep Erythrocytes ◽  
Uptake Rates

1. Uptake rates for 23 amino acids were measured for both normal (high-GSH) and GSH-deficient (low-GSH) erythrocytes from Finnish Landrace sheep. 2. Compared with high-GSH cells, low-GSH cells had a markedly diminished permeability to D-alanine, L-alanine, α-amino-n-butyrate, valine, cysteine, serine, threonine, asparagine, lysine and ornithine. Smaller differences were observed for glycine and proline, whereas uptake of the other amino acids was not significantly different in the two cell types.

THE ENZYMES OF THE TRICARBOXYLIC ACID CYCLE OF PSEUDOMONAS AERUGINOSA

1956 ◽  
Vol 2 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Jack J. R. Campbell ◽  
Roberts A. Smith
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Malic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
The Other ◽  
Acid Cycle ◽  
High Ph ◽  
Optimum Activity ◽  
Fresh Cell ◽  
Cell Extracts

It was demonstrated that Pseudomonas aeruginosa possesses all the enzymes necessary for the oxidation of pyruvate to CO2 and water without passing through the conventional intermediates oxalosuccinate and α-ketoglutarate. These intermediates are bypassed by the action of the enzyme isocitratase which splits d-isocitrate to succinate plus glyoxylate. This reaction was shown to be readily reversible. The malic acid dehydrogenase content was low and in addition this enzyme required a high pH for optimum activity. In fresh cell extracts at pH 7.4 its activity was only 10% that of the other enzymes of the cycle. The malic and isocitric dehydrogenases were TPN specific. The organism was also shown to possess all the enzymes necessary for the operation of the conventional tricarboxylic acid cycle.

scholarly journals Antibodies against Ribosomal Phosphoprotein P0 ofPlasmodium falciparum Protect Mice against Challenge with Plasmodium yoelii

2000 ◽  
Vol 68 (7) ◽  
pp. 4312-4318 ◽  
Author(s):  
Sanchita Chatterjee ◽  
Subhash Singh ◽  
Rashmi Sohoni ◽  
Nevil J. Singh ◽  
Akhil Vaidya ◽  
...  
Keyword(s):  
Amino Acids ◽  
Deae Cellulose ◽  
Plasmodium Yoelii ◽  
Malarial Parasite ◽  
Immunization Schedule ◽  
Ofplasmodium Falciparum ◽  
P0 Protein ◽  
Recombinant Polypeptides ◽  
Blocking Antibodies ◽  
35 Kda Protein

ABSTRACT Antibodies against the Plasmodium falciparum P0 ribosomal phosphoprotein (PfP0) have been detected exclusively but extensively in malaria-immune persons. Polyclonal rabbit and mice sera were raised against two recombinant polypeptides of P. falciparum P0 protein, PfP0N and PfP0C, covering amino acids 17 to 61 and the remaining amino acids 61 to 316, respectively. Sera against both these domains detected a 35-kDa protein fromPlasmodium yoelii subsp. yoelii, a rodent malarial parasite, and stained the surface of merozoites in immunofluorescence assays. Total immunoglobulin G (IgG) purified from rabbit and mouse anti-PfP0 sera by ammonium sulfate and DEAE-cellulose chromatography was used for passive transfer experiments in mice. Mice passively immunized with both anti-PfP0N and anti-PfP0C showed distinctly lower levels of parasitemia than control mice. With immunizations on days −1, 0, 1, 3, and 5, about 50% of both sets of mice receiving anti-PfP0N and anti-PfP0C cleared the lethal 17XL strain of P. yoelii and revived by day 25. All the control mice died by day 10. By extending the immunization schedule, the survival period of the mice could be extended for every mouse that received anti-PfP0 IgG. These data demonstrate the cross-protection of the anti-PfP0 IgG and establish parasite P0 protein as a target for invasion-blocking antibodies.

Changes in Seryl-tRNA Formative in Developing Chick Muscle

1974 ◽  
Vol 52 (10) ◽  
pp. 838-844 ◽  
Author(s):  
Mark Nwagwu ◽  
John Lianga
Keyword(s):  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Deae Cellulose ◽  
The Other ◽  
Embryonic Chick ◽  
Qualitative And Quantitative ◽  
Embryonic Muscle ◽  
Quantitative Changes ◽  
The One

As a prelude to an analysis of the dependence of muscle protein synthesis on aminoacyl tRNA's, we have investigated the rates of seryl-tRNA formation, in vitro, by aminoacylating systems isolated from 11-, 14-, and 17-day chick embryonic muscle. The results show that the combination of 14-day tRNA and 14-day aminoacyl synthetase is the most efficient in seryl-tRNA formation. We have also studied the qualitative and quantitative changes in seryl-tRNA prepared from 11-, 14-, and 17-day embryonic chick muscle by chromatography of seryl-tRNA on benzoylated DEAE-cellulose columns. The results show that, although there are no qualitative differences in the chromatographic patterns of seryl-tRNA from the different ages, there are significant quantitative differences between the patterns for 11-day and 17-day seryl-tRNA on the one hand, and the pattern for 14-day seryl-tRNA on the other.

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