scholarly journals Induction of N-acetylglucosamine kinase in yeast

1974 ◽  
Vol 141 (2) ◽  
pp. 593-595 ◽  
Author(s):  
A. Bhattacharya ◽  
M. Puri ◽  
A. Datta
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Candida Albicans ◽  
Enzyme Synthesis ◽  
Transcriptional Level ◽  
Protein Synthesis Inhibitors ◽  
Rna And Protein Synthesis ◽  
New Protein

The presence of N-acetylglucosamine is essential for the induced synthesis of N-acetylglucosamine kinase in Candida albicans. The enzyme synthesis stops and its concentration in the cells declines rapidly as soon as N-acetylglucosamine is removed from the medium. Experiments with RNA- and protein-synthesis inhibitors indicate that the appearance of new enzyme activity is dependent on concomitant new protein synthesis and the inducer operates at a transcriptional level.

scholarly journals Induction of N-acetylglucosamine-catabolic pathway in spheroplasts of Candida albicans

1979 ◽  
Vol 178 (2) ◽  
pp. 427-431 ◽  
Author(s):  
B Singh ◽  
A Datta
Keyword(s):  
Protein Synthesis ◽  
Candida Albicans ◽  
Enzyme Activities ◽  
Transcriptional Level ◽  
Uptake System ◽  
Catabolic Pathway ◽  
High Affinity ◽  
Catabolic Enzymes ◽  
Rna And Protein Synthesis ◽  
New Protein

Synthesis of N-acetylglucosamine-catabolic enzymes, namely permease (high-affinity uptake system), kinase and deaminase was studied in the spheroplasts of the yeast Candida albicans. The presence of N-acetylglucosamine as inducer is essential for the induced synthesis of these enzymes in the spheroplasts, which were active for at least 8–9 h. However, some of the newly synthesized kinase and deaminase leaked out from the spheroplasts into the medium during induction. Experiments with inhibitors of RNA and protein synthesis indicate that the appearance of new enzyme activities is dependent on concomitant new protein synthesis and the inducer operates at a transcriptional level. However, inhibitors of DNA synthesis, e.g. mitomycin-C and hydroxyurea, had no effect on the synthesis of these enzymes.

Metabolic requirements for interactions between nuclear and cytoplasmic membranes in the repair of damaged Amoeba nuclei

1976 ◽  
Vol 21 (2) ◽  
pp. 291-302
Author(s):  
C.J. Flickinger
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Synthesis ◽  
Membrane Fusion ◽  
Energy Production ◽  
Rna Synthesis ◽  
Metabolic Inhibitors ◽  
Protein Synthesis Inhibitors ◽  
Nuclear Membranes ◽  
Cytoplasmic Membranes ◽  
Rna And Protein Synthesis

Amoeba nuclear envelopes were damaged using microsurgery, and metabolic requirements for the steps in their repair were studied, and my placing the cells in a solution containing one of several metabolic inhibitors. The first step in repair, the association of pieces of endoplasmic reticulum with holes in the nuclear membranes, appears to be a passive process since it was not affected by inhibitors of energy production, RNA synthesis, or protein synthesis. In contrast, fusion of pieces of endoplasmic reticulum with the nuclear membranes at the margins of the holes was blocked by KCN and dinitrophenol, indicating that membrane fusion requires energy derived from respiration, but RNA and protein synthesis inhibitors did not prevent fusion of pieces of endoplasmic reticulum with the nuclear membranes. The subsequent completion of repair and restoration of intact nuclear membranes was almost completely blocked by inhibitors of respiration, and it was reduced in the presence of actinomycin and emetine, suggesting that in addition to a requirement for energy, some later steps in the repair of the nuclear membranes require RNA and protein synthesis.

THE DEVELOPMENT OF AN IN VITRO SYSTEM FOR ESTIMATING OXYTOCINASE IN THE RABBIT HYPOTHALAMUS AND THE EFFECTS OF SOME PROTEIN SYNTHESIS INHIBITORS AND OESTRADIOL-17β ON ENZYME ACTIVITY

1974 ◽  
Vol 75 (3) ◽  
pp. 443-451 ◽  
Author(s):  
Dona A. Frith ◽  
K. C. Hooper
Keyword(s):  
Protein Synthesis ◽  
Enzyme Activity ◽  
Steroid Hormones ◽  
Actinomycin D ◽  
Protein Synthesis Inhibitors ◽  
In Vitro System

ABSTRACT An in vitro system for investigating the effects of steroid hormones and protein synthesis inhibitors on hypothalamic peptidases inactivating oxytocin has been developed. In the presence of oestradiol-17β enzyme activity was increased in the in vitro system whilst this increase was blocked completely by cycloheximide and partially blocked by actinomycin-D. It is apparent therefore that oestradiol-17β acts directly on the hypothalamus stimulating oxytocinase activity.

scholarly journals Genes for Drosophila small heat shock proteins are regulated differently by ecdysterone.

1991 ◽  
Vol 11 (12) ◽  
pp. 5937-5944 ◽  
Author(s):  
J Amin ◽  
R Mestril ◽  
R Voellmy
Keyword(s):  
Protein Synthesis ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Small Heat Shock Proteins ◽  
Transcriptional Level ◽  
Protein Synthesis Inhibitors ◽  
Sequence Elements ◽  
Continuous Presence ◽  
High Level ◽  
Shock Proteins

Genes for small heat shock proteins (hsp27 to hsp22) are activated in late third-instar larvae of Drosophila melanogaster in the absence of heat stress. This regulation has been simulated in cultured Drosophila cells in which the genes are activated by the addition of ecdysterone. Sequence elements (HERE) involved in ecdysterone regulation of the hsp27 and hsp23 genes have been defined by transfection studies and have recently been identified as binding sites for ecdysterone receptor. We report here that the hsp27 and hsp23 genes are regulated differently by ecdysterone. The hsp27 gene is activated rapidly by ecdysterone, even in the absence of protein synthesis. In contrast, high-level expression of the hsp23 gene begins only after a lag of about 6 h, is dependent on the continuous presence of ecdysterone, and is sensitive to low concentrations of protein synthesis inhibitors. Transfection experiments with reporter constructs show that this difference in regulation is at the transcriptional level. Synthetic hsp27 or hsp23 HERE sequences confer hsp27- or hsp23-type ecdysterone regulation on a basal promoter. These findings indicate that the hsp27 gene is a primary, and the hsp23 gene is mainly a secondary, hormone-responsive gene. Ecdysterone receptor is implied to play a role in the regulation of both genes.

Ultrastructural investigation of the effect of DNA, RNA, and protein synthesis inhibitors on ribosome crystallization

1973 ◽  
Vol 44 (3-4) ◽  
pp. 265-278 ◽  
Author(s):  
Nadir M. Maraldi ◽  
Graziella Biagini ◽  
Paolo Simoni ◽  
Marcello Barbieri ◽  
Marina Marini ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Synthesis Inhibitors ◽  
Ultrastructural Investigation ◽  
Rna And Protein Synthesis

scholarly journals Haem control in experimental porphyria. The effect of haemin on the induction of δ-aminolaevulinate synthase in isolated chick-embryo liver cells

1980 ◽  
Vol 188 (3) ◽  
pp. 781-788 ◽  
Author(s):  
Gopesh Srivastava ◽  
John D. Brooker ◽  
Brian K. May ◽  
William H. Elliott
Keyword(s):  
Protein Synthesis ◽  
Chick Embryo ◽  
Liver Cells ◽  
Enzyme Synthesis ◽  
Primary Effect ◽  
A Value ◽  
Low Concentrations ◽  
Methane Sulphonate ◽  
Rna And Protein Synthesis ◽  
Embryo Liver

2-Allyl-2-isopropylacetamide-mediated induction of hepatic porphyria was studied in isolated chick-embryo liver cells. Increased δ-aminolaevulinate synthase activity occurred within 1h of induction and continued to increase for 8h. Protoporphyrins synthesized during this time accumulated to a concentration 10-fold greater than that in the control. Removal of 2-allyl-2-isopropylacetamide from the cells by washing at 3h immediately inhibited further increases in δ-aminolaevulinate synthase synthesis. However substitution of 2-allyl-2-isopropylacetamide at 3h by deferoxamine methane-sulphonate, an inhibitor of haem synthesis, allowed continued δ-aminolaevulinate synthase induction at an unaltered rate, even though this agent did not, by itself, induce enzyme synthesis. Exogenously added haemin was shown completely to inhibit 2-allyl-2-isopropylacetamide-mediated δ-aminolaevulinate synthase induction at concentrations as low as 20nm, a value that is less than the reported physiological one. The duration of inhibition was dependent on the concentration of added haemin and was followed by a period of δ-aminolaevulinate synthase synthesis at a rate similar to that of the control. These data are consistent with the hypothesis that δ-aminolaevulinate synthase synthesis is regulated by the concentration of intracellular haem and that induction is initiated by 2-allyl-2-isopropylacetamide-mediated destruction of haem. Induction of δ-aminolaevulinate synthase was shown to be dependent on both RNA and protein synthesis, and a study of the comparative effects of cordycepin, cycloheximide and haem has shown that, at haemin concentrations up to 50nm, the inhibition of δ-aminolaevulinate synthase synthesis followed kinetics similar to the effect of cordycepin, with no synergism between cordycepin and 50nm-haemin. However, at a haemin concentration of 2μm, the inhibition of δ-aminolaevulinate synthase synthesis followed similar kinetics to the effect of cycloheximide. These data demonstrate the control of δ-aminolaevulinate synthase synthesis by low concentrations of haemin and suggests that the primary effect of haemin is at the level of transcription.

scholarly journals Biosynthesis in vitro of tryptophanase by polyribosomes from induced cultures of Escherichia coli

1971 ◽  
Vol 123 (3) ◽  
pp. 355-365 ◽  
Author(s):  
S. A. M. Khairul Bashar ◽  
J. H. Parish ◽  
Marjorie Brown
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Enzyme Activity ◽  
Amino Acid ◽  
Enzyme Synthesis ◽  
Supernatant Fraction ◽  
Amino Acid Residues ◽  
Radioactive Amino Acid ◽  
Tryptophanase Activity

1. Polyribosomes were isolated from Escherichia coli grown in media in which tryptophanase is induced and in which it is repressed. The polyribosomes from the induced bacteria had a small amount of tryptophanase activity associated with them. 2. A portion of the enzyme activity remained bound to polyribosomes during centrifuging in sucrose gradients. 3. Incubation of tryptophanase-containing polyribosomes with puromycin released enzyme activity. 4. The binding of the enzyme to the polyribosomes did not depend on the presence of DNA. 5. When the polyribosomes were incubated under conditions of protein synthesis with supernatant fraction obtained from repressed bacteria, a small but statistically significant increase in enzyme activity was produced. 6. When a radioactive amino acid was included in the incubation mixture for the tryptophanase system a radioactive protein was obtained whose chromatographic, electrophoretic and sedimentation properties were identical with those of tryptophanase. 7. The amount of incorporation was consistent with the amount of new enzyme synthesis predicted by the increase in enzyme activity. Both radioactive incorporation and increase in enzyme activity were shown to be energy-dependent and also negative controls were obtained by using zero-time incubations or polyribosomes isolated from either repressed cells or a mutant lacking the ability to produce tryptophanase. 8. The distribution of radioactive leucine in the carboxyl region of the newly labelled tryptophanase was examined by digesting the labelled protein with carboxypeptidases. It was shown that the radioactivity was more highly concentrated towards the carboxyl terminus when the incubation times for protein synthesis were shorter (implying that, with longer incubation times, longer lengths of polypeptide chain contained radioactive amino acid residues).

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