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.

FEMALE ENDOCRINE CONTROL MECHANISMS DURING THE NEONATAL PERIOD

1972 ◽  
Vol 70 (2) ◽  
pp. 396-408 ◽  
Author(s):  
K.-D. Schulz ◽  
H. Haarmann ◽  
A. Harland
Keyword(s):  
Protein Synthesis ◽  
Reproductive System ◽  
Rna Synthesis ◽  
Neonatal Period ◽  
High Dose ◽  
Female Reproductive System ◽  
Endocrine Control ◽  
Hypothalamic Region ◽  
Rna And Protein Synthesis ◽  
Physiological Dose

ABSTRACT The present investigation deals with the oestrogen-sensitivity of the female reproductive system during the neonatal period. Newborn female guinea pigs were used as test animals. At different times after a single subcutaneous injection of a physiological dose of 0.1 μg or an unphysiologically high dose of 10 μg 17β-oestradiol/100 g body weight, the RNA- and protein-synthesis was examined in the hypothalamic region, pituitary, cerebral cortex, liver, adrenal gland, ovary and uterus. With a physiological dose an increase in organ weight, protein content, RNA-and protein-synthesis was found only in the uterus. These alterations turned out to be dose-dependent. In addition to the findings in the uterus an inhibition of the aminoacid incorporation rate occurred in the liver following the injection of the high oestradiol dose. As early as 1 hour after the administration of 0.1 μg 17β-oestradiol an almost 100% increase in uterine protein synthesis was detectable. This result demonstrates a high oestrogen-sensitivity of this organ during the neonatal period. All the other organs of the female reproductive system such as the hypothalamus, pituitary and ovary did not show any oestrogen response. Therefore the functional immaturity of the uterus during post partem life is not the result of a deficient hormone sensitivity but is correlated with the absence of a sufficient hormonal stimulus at this time. The investigation on the effects of actinomycin resulted in different reactions in the uterus and liver. In contrast to the liver a paradoxical actinomycin effect was found in the uterus after treatment with actinomycin alone. This effect is characterized by a small inhibition of RNA-synthesis and a 50% increase in protein synthesis. The treatment of the newborn test animals with actinomycin and 17β-oestradiol together abolished the oestrogen-induced stimulation of the uterine RNA-and protein-synthesis. Consequently, the effect of oestrogens during the neonatal period is also connected with the formation of new proteins via an increased DNA-directed RNA-synthesis.

scholarly journals Specific mRNA destabilization in Dictyostelium discoideum requires RNA synthesis.

1987 ◽  
Vol 7 (12) ◽  
pp. 4585-4588 ◽  
Author(s):  
J F Amara ◽  
H F Lodish
Keyword(s):  
Protein Synthesis ◽  
Dictyostelium Discoideum ◽  
Rna Synthesis ◽  
Protein Synthesis Inhibitors ◽  
Protein And Rna Synthesis ◽  
The Common ◽  
Mrna Destabilization ◽  
Actin Protein ◽  
Specific Mrna

We tested the effects of inhibitors of protein and RNA synthesis on the disaggregation-mediated destabilization of prespore mRNAs in Dictyostelium discoideum. Incubating disaggregated cells with daunomycin to inhibit RNA synthesis prevented the loss of prespore mRNAs, whereas the inhibitor decreased or did not affect levels of the common mRNAs CZ22 and actin. Protein synthesis inhibitors varied in their effects. Cycloheximide, which inhibited protein synthesis almost completely, prevented the loss of the prespore mRNAs, but puromycin, which inhibited protein synthesis less well, did not. These results indicate that the process of specific mRNA destabilization requires the synthesis of RNA and possibly of protein.

A STUDY ON THE EFFECT OF INSULIN ON DNA, RNA AND PROTEIN SYNTHESIS IN MOUSE MAMMARY GLAND TISSUE IN ORGAN CULTURE

1971 ◽  
Vol 50 (2) ◽  
pp. 241-249 ◽  
Author(s):  
D. Y. WANG ◽  
VICKY AMOR
Keyword(s):  
Protein Synthesis ◽  
Mammary Gland ◽  
Organ Culture ◽  
Mouse Mammary Gland ◽  
Metabolic Inhibitors ◽  
Synthetic Activity ◽  
Insulin Stimulation ◽  
Mammary Gland Tissue ◽  
Gland Tissue ◽  
Rna And Protein Synthesis

SUMMARY The rates of synthesis of DNA, RNA and protein of mouse mammary gland explants in organ culture have been determined. Stimulation with insulin resulted in maximal rates of synthesis of these components, all occurring between 18 and 22 h of culture. The use of metabolic inhibitors of DNA, RNA or protein synthesis showed that after insulin stimulation, inhibition of any one of these processes was associated with a reduction in the synthesis of the other two components. Also the maximal rate of protein synthesis is governed by the net amount of RNA formed throughout the period of culture. Evidence is presented that the stimulation of DNA, RNA or protein synthesis by insulin is not due to increased transport of amino acids and that insulin appears to act rapidly on processes which subsequently lead to enhanced synthetic activity.

scholarly journals A Synthetic Congener Modeled on a Microbicidal Domain of Thrombin- Induced Platelet Microbicidal Protein 1 Recapitulates Staphylocidal Mechanisms of the Native Molecule

2006 ◽  
Vol 50 (11) ◽  
pp. 3786-3792 ◽  
Author(s):  
Yan Q. Xiong ◽  
Arnold S. Bayer ◽  
Lisa Elazegui ◽  
Michael R. Yeaman
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Membrane Permeabilization ◽  
Dna And Rna ◽  
Activated Platelets ◽  
Rna And Protein Synthesis ◽  
Dna And Rna Synthesis ◽  
Platelet Microbicidal Protein ◽  
Α Helix ◽  
Native Host

ABSTRACT Thrombin-induced platelet microbicidal protein 1 (tPMP-1) is a staphylocidal peptide released by activated platelets. This peptide initiates its microbicidal activity by membrane permeabilization, with ensuing inhibition of intracellular macromolecular synthesis. RP-1 is a synthetic congener modeled on the C-terminal microbicidal α-helix of tPMP-1. This study compared the staphylocidal mechanisms of RP-1 with those of tPMP-1, focusing on isogenic tPMP-1-susceptible (ISP479C) and -resistant (ISP479R) Staphylococcus aureus strains for the following quantitative evaluations: staphylocidal efficacy; comparative MIC; membrane permeabilization (MP) and depolarization; and DNA, RNA, and protein synthesis. Although the proteins had similar MICs, RP-1 caused significant killing of ISP479C (<50% survival), correlating with extensive MP (>95%) and inhibition of DNA and RNA synthesis (>90%), versus substantially reduced killing of ISP479R (>80% survival), with less MP (55%) and less inhibition of DNA or RNA synthesis (70 to 80%). Interestingly, RP-1-induced protein synthesis inhibition was equivalent in both strains. RP-1 did not depolarize the cell membrane and caused a relatively short postexposure growth inhibition. These data closely parallel those previously reported for tPMP-1 against this strain set and exemplify how synthetic molecules can be engineered to reflect structure-activity relationships of functional domains in native host defense effector molecules.

scholarly journals Precommitted erythroid cells enriched in cultures of suboptimally induced Friend erythroleukemia cells

Blood ◽  
1987 ◽  
Vol 70 (5) ◽  
pp. 1565-1571
Author(s):  
E DiMambro ◽  
M Galanti ◽  
SB Levy
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Terminal Differentiation ◽  
Metabolic Inhibitors ◽  
Hemoglobin Synthesis ◽  
Erythroleukemia Cells ◽  
Chemically Induced ◽  
Primed Cell ◽  
Murine Erythroleukemia ◽  
New Protein

Abstract In the presence of suboptimal inducing amounts of dimethylsulfoxide or hexamethylenebisacetamide, a major proportion of uncommitted murine erythroleukemia (MEL) cells was found to be precommitted or primed for commitment, which was demonstrated by their rapid commitment to terminal differentiation when recultured for short periods of time (three to six hours) with fresh inducer. These same cells did not commit if left in the original inducer-containing media or if replated in fresh media without inducer. The two inducers could be interchanged in the priming and postpriming period without affecting the commitment event. However, hemin, an agent that induces hemoglobin synthesis without commitment, showed no ability to enhance commitment of a primed cell population. The rapid commitment of primed cells was inhibited by 12-O-tetradecanoylphorbol-13-acetate and cordycepin but not by cycloheximide. The latter finding indicated that this rapid inducer- dependent commitment event required new RNA synthesis but not new protein synthesis. The precommitment state was lost within six hours of the growth of cells in the absence of inducer but could be sustained longer if cells were incubated in cycloheximide. These studies characterize a precommitment state not previously described and one that appears during chemically induced differentiation in the absence of metabolic inhibitors. The stabilization of these precommitted cells by cycloheximide suggests that the reversibility of precommitment involves new protein synthesis. These findings show that MEL cells proceed to terminal differentiation by accumulating unstable products that must be maintained by the inducer until the final commitment event.

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.

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
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