Phosphate-Transport Appearance in the Sea-Urchin Egg. I. Effects of Protein-Synthesis Inhibitors on Fertilized Eggs and Embryos

1974 ◽  
Vol 52 (6) ◽  
pp. 1178-1185 ◽  
Author(s):  
Joël de la Noüe
Keyword(s):  
Protein Synthesis ◽  
Active Transport ◽  
Sea Urchin ◽  
Developmental Stages ◽  
Sea Water ◽  
Mitochondrial Protein ◽  
Phosphate Transport ◽  
Inhibitory Effect ◽  
Protein Synthesis Inhibitors ◽  
Transport Carrier

When fertilized eggs of Strongylocentrotus purpuratus, the purple sea urchin, are incubated in sea water containing 32PO43− and L-14C-valine, valine incorporation is inhibited in the presence of puromycin, cycloheximide, or chloramphenicol, but only the last inhibits the active transport of phosphate. Since chloramphenicol does not depress the egg respiration, it is likely that this drug acts specifically. This is in line with a lack of inhibitory effect of chloramphenicol on phosphate uptake at later developmental stages, except at the time of gastrulation, when the appearance of new phosphate carriers might well occur. It is suggested that the active transport carrier for phosphate, or some element required for its operation, is synthesized after fertilization, with the likely participation of the mitochondrial protein-synthesis machinery. A similar proposal holds for valine uptake.

Effects of mycoplasma contamination on phenotypic expression of mitochondrial mutants in human cells

1981 ◽  
Vol 1 (4) ◽  
pp. 321-329
Author(s):  
C J Doersen ◽  
E J Stanbridge
Keyword(s):  
Protein Synthesis ◽  
Infected Cell ◽  
Cell Lines ◽  
Resistant Strain ◽  
Drug Sensitivity ◽  
Mitochondrial Protein ◽  
Phenotypic Expression ◽  
Mitochondrial Protein Synthesis ◽  
Protein Synthesis Inhibitors

HeLa cells sensitive to the mitochondrial protein synthesis inhibitors erythromycin (ERY) and chloramphenicol (CAP) and HeLa variants resistant to the effects of these drugs were purposefully infected with drug-sensitive and -resistant mycoplasma strains. Mycoplasma hyorhinis and the ERY-resistant strain of Mycoplasma orale, MO-ERYr, did not influence the growth of HeLa and ERY-resistant ERY2301 cells in the presence or absence of ERY. M. hyorhinis also did not affect the growth of HeLa and CAP-resistant Cap-2 cells in the presence or absence of CAP. However, both HeLa and Cap-2 cells infected with the CAP-resistant strain of M. hyorhinis, MH-CAPr, were more sensitive to the cytotoxic effect of CAP. This may be due to the glucose dependence of the cells, which was compromised by the increased utilization of glucose by MH-CAPr in these infected cell cultures. In vitro protein synthesis by isolated mitochondria was significantly altered by mycoplasma infection of the various cell lines. A substantial number of mycoplasmas copurified with the mitochondria, resulting in up to a sevenfold increase in the incorporation of [3H]leucine into the trichloroacetic acid-insoluble material. More importantly, the apparent drug sensitivity or resistance of mitochondrial preparations from mycoplasma-infected cells reflected the drug sensitivity or resistance of the contaminating mycoplasmas. These results illustrate the hazards in interpreting mitochondrial protein synthesis data derived from mycoplasma-infected cell lines, particularly putative mitochondrially encoded mutants resistant to inhibitors of mitochondrial protein synthesis.

Investigation of the mode of nuclear control over protein synthesis in early development of loach and sea urchin

Development ◽  
1972 ◽  
Vol 28 (3) ◽  
pp. 491-509
Author(s):  
Maya R. Krigsgaber ◽  
A. A. Neyfakh
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Ionizing Radiation ◽  
Radiation Damage ◽  
Sea Urchin ◽  
Rna Synthesis ◽  
Developmental Stages ◽  
Subsequent Development ◽  
Long Term Treatment ◽  
Androgenetic Haploid

It is shown that in loach embryos the incorporation of precursors into protein takes place in the blastoderm cells only. The change of the rate of incorporation of labelled amino acids into protein of the blastoderm separated from the yolk at successive developmental stages reflects the changes in the level of protein synthesis in intact embryos of the same developmental stages. Typical periodic changes of the intensity of protein synthesis in early embryo-genesis of the loach are detected: low incorporation of amino acids at blastula stages is followed by an increase of synthesis during gastrulation and by a decrease with the onset of organogenesis. To study the genetic control over protein synthesis at various developmental stages of loach and sea-urchin embryos the effects of ionizing radiation and long-term treatment with actinomycin D have been examined. X-Irradiation doses produce an insignificant direct effect on protein synthesis, while radiation damage of the nuclear apparatus results in a gradual but ever increasing inhibition of protein synthesis. The inhibition of RNA synthesis with actinomycin or ionizing radiation damage of the nuclei produce essentially the same effect on the intensity of protein synthesis. Protein synthesis in androgenetic haploid hybrid embryos (loach ♀ × goldfish ♂) and in loach androgenetic haploid embryos after producing a partial elimination of chromosomes does not differ from ‘enucleated’ loach embryos completely deprived of chromosomes. These data suggest that high-polymeric RNA formed after the elimination of some chromsomes is unable to provide a normal level of protein synthesis. Protein synthesis is not controlled by the nuclei up to the stages of early blastula (sea urchin) and of late blastula (loach), being evidently programmed in oogenesis. To provide a rapid activation of protein synthesis in the course of gastrulation in the loach the function of the nuclei has to be realized during mid-blastula stages. An increase of the rate of the incorporation of amino acids at the stages of mesenchyme blastula in the sea urchin depends on the synthesis of RNA at the early blastula. At the same time protein synthesis during gastrulation in the loach and at mesenchyme blastula in the sea urchin is much less dependent on the simultaneous RNA synthesis. Protein synthesis at these stages seems to be provided by the long-living templates and controlled by non-gene mechanisms of the regulation of translation. Thus early embryonic differentiation in the loach and sea-urchin development is related to the activation of protein synthesis. The latter is provided by the preceding morphogenetic nuclear function, which makes protein synthesis relatively independent of simultaneous synthesis of templates that ensures subsequent development stages.

Oxytetracycline inhibition of mitochondrial protein synthesis in bovine lymphocytes infected withTheileria parvaor stimulated by mitogen

Parasitology ◽  
1990 ◽  
Vol 101 (3) ◽  
pp. 387-393 ◽  
Author(s):  
P. R. Spooner
Keyword(s):  
Protein Synthesis ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Oxidase Activity ◽  
Mitochondrial Protein ◽  
Inhibitory Effect ◽  
Mitochondrial Protein Synthesis ◽  
Drug Concentrations ◽  
Bovine Lymphocytes

SUMMARYOxytetracycline (OTC) significantly inhibited cytochrome c oxidase activity in bovine lymphocytes infected withTheileria parvaand in uninfected mitogen-stimulated lymphocytes. The inhibitory effect was detectedin vitrowithin 24 h of treatment with drug concentrations as low as 1 µg/ml. Following mitogen stimulation of lymphocytes, concentrations of 3 and 10 µg/ml OTC completely inhibited an increase in cytochrome c oxidase activity for 48–72 h. This inhibitory activity was considered to be due to a direct effect on lymphoblast mitochondrial protein synthesis. As a consequence, adenosine triphosphate activity was significantly reduced in lymphocytes stimulated either by infection withT. parvasporozoites or by mitogen and then treated with OTC. The results also indicated that parasite mitochondrial protein synthesis was inhibited by OTC. The activity of OTC reported in this study could explain the suppression of disease following ‘infection and treatment’ immunization against East Coast fever and thein vitrodrug-inhibition of schizont development.

scholarly journals ANTIGENS IN EGGS AND DEVELOPMENTAL STAGES OF THE SEA URCHIN

1964 ◽  
Vol 22 (2) ◽  
pp. 307-316 ◽  
Author(s):  
Peter Perlmann ◽  
Jane Couffer-Kaltenbach
Keyword(s):  
Sea Urchin ◽  
Developmental Stages ◽  
Sea Water ◽  
Paracentrotus Lividus ◽  
Protein Antigens ◽  
Preparative Scale ◽  
Low Speed ◽  
Diffusion Technique ◽  
Cell Fractions ◽  
Isolated Cell

Homogenates of fertilized eggs of the sea urchin Paracentrotus lividus were fractionated by differential centrifugation. In addition, whole eggs were fragmented, on a preparative scale, by centrifugation in sea water-sucrose gradients. The fractions and fragments were subsequently assayed for their content of soluble protein antigens described in an earlier publication. Relative concentrations of antigen present in quantitatively isolated cell fractions were estimated by graded antiserum absorption in combination with agar-diffusion technique. Two of six antigens were found to be associated mainly with the low speed sediments. Treatment of the various sediments with hypotonic medium and results obtained with fragmented eggs suggested that these two antigens and possibly a third were probably located in the yolk granules. The other antigens were more evenly distributed among the low speed sediments and the non-sedimented part of the cytoplasm. Only one of the antigens was consistently associated with the microsomal fraction.

scholarly journals Differences in degradation processes for insulin and its receptor in cultured foetal hepatocytes

1983 ◽  
Vol 212 (3) ◽  
pp. 529-537 ◽  
Author(s):  
E Pringault ◽  
C Plas
Keyword(s):  
Protein Synthesis ◽  
Insulin Receptors ◽  
Insulin Binding ◽  
Inhibitory Effect ◽  
Insulin Degradation ◽  
Protein Synthesis Inhibitors ◽  
Degradation Processes ◽  
Degradation Rates ◽  
Number Of Binding Sites ◽  
The Stability

Binding and degradation of 125I-labelled insulin were studied in cultured foetal hepatocytes after exposure to the protein-synthesis inhibitors tunicamycin and cycloheximide. Tunicamycin (1 microgram/ml) induced a steady decrease of insulin binding, which was decreased by 50% after 13 h. As the total number of binding sites per hepatocyte was 20000, the rate of the receptor degradation could not exceed 13 sites/min per hepatocyte. Cycloheximide (2.8 micrograms/ml) increased insulin binding by 30% within 6 h, an effect that persisted for up to 25 h. This drug had a specific inhibitory effect on the degradation of proteins prelabelled for 10 h with [14C]glucosamine, without affecting the degradation of total proteins. Chronic exposure to 10 nM-insulin neither decreased insulin binding nor modified the effect of the drugs. The absence of down-regulation of insulin receptors cannot be attributed to rapid receptor biosynthesis in foetal hepatocytes. Cellular insulin degradation, which is exclusively receptor-mediated, was determined by two different parameters. First, the rate of release of degraded insulin into the medium was 600 molecules/min per hepatocyte with 1 nM labelled hormone, and increased (preincubation with cycloheximide) or decreased (tunicamycin) as a function of the amount of cell-bound insulin. Secondly, the percentage of cell-bound insulin degraded was not changed by the presence of protein-synthesis inhibitors (25-30%). The stability of insulin degradation suggested that this process was dependent on long-life proteinase systems. Such differences in degradation rates and cycloheximide sensitivity imply that hormone- and receptor-degradation processes utilize distinct pathways.

scholarly journals Effects of mycoplasma contamination on phenotypic expression of mitochondrial mutants in human cells.

1981 ◽  
Vol 1 (4) ◽  
pp. 321-329 ◽  
Author(s):  
C J Doersen ◽  
E J Stanbridge
Keyword(s):  
Protein Synthesis ◽  
Infected Cell ◽  
Cell Lines ◽  
Resistant Strain ◽  
Drug Sensitivity ◽  
Mitochondrial Protein ◽  
Phenotypic Expression ◽  
Mitochondrial Protein Synthesis ◽  
Protein Synthesis Inhibitors

HeLa cells sensitive to the mitochondrial protein synthesis inhibitors erythromycin (ERY) and chloramphenicol (CAP) and HeLa variants resistant to the effects of these drugs were purposefully infected with drug-sensitive and -resistant mycoplasma strains. Mycoplasma hyorhinis and the ERY-resistant strain of Mycoplasma orale, MO-ERYr, did not influence the growth of HeLa and ERY-resistant ERY2301 cells in the presence or absence of ERY. M. hyorhinis also did not affect the growth of HeLa and CAP-resistant Cap-2 cells in the presence or absence of CAP. However, both HeLa and Cap-2 cells infected with the CAP-resistant strain of M. hyorhinis, MH-CAPr, were more sensitive to the cytotoxic effect of CAP. This may be due to the glucose dependence of the cells, which was compromised by the increased utilization of glucose by MH-CAPr in these infected cell cultures. In vitro protein synthesis by isolated mitochondria was significantly altered by mycoplasma infection of the various cell lines. A substantial number of mycoplasmas copurified with the mitochondria, resulting in up to a sevenfold increase in the incorporation of [3H]leucine into the trichloroacetic acid-insoluble material. More importantly, the apparent drug sensitivity or resistance of mitochondrial preparations from mycoplasma-infected cells reflected the drug sensitivity or resistance of the contaminating mycoplasmas. These results illustrate the hazards in interpreting mitochondrial protein synthesis data derived from mycoplasma-infected cell lines, particularly putative mitochondrially encoded mutants resistant to inhibitors of mitochondrial protein synthesis.

Further studies of the effects of deprivation of sulfate on the early development of the sea urchin Paracentrotus lividus

Development ◽  
1965 ◽  
Vol 14 (3) ◽  
pp. 289-305
Author(s):  
J. Immers ◽  
J. Runnström
Keyword(s):  
Sea Urchin ◽  
Developmental Stages ◽  
Sea Water ◽  
Sea Urchins ◽  
Paracentrotus Lividus ◽  
The Other ◽  
Free Medium ◽  
Dominant Group ◽  
And Function ◽  
Early Developmental

The morphological effects of sulfate-free medium on sea urchin embryos were described in detail by Herbst (1904). Further studies were carried out by Lindahl (1936, 1942). He was the first to consider metabolic aspects of the rôle of sulfate in the development of the sea urchin. Immers (1956, 1959, 1961a and b, 1962) studied the distribution and function of acid mucopolysaccharides in early developmental stages of sea urchins, mainly Paracentrotus lividus. A dominant group of these acid polysaccharides are sulfated. Their location in the blastocoel, in the hyaline layer and in the lumen of the intestine could be demonstrated by staining of sectioned specimens with the ferri-acetic reagent of Hale (1946). In blastulae or gastrulae raised in sulfate-free sea water these regions are negative with respect to Hale staining (Immers, 1961b). On the other hand, the ectodermal nuclei of the animal region of the embryos are stained with the Hale reagent although the nuclei of the vegetal region remained unstained (1.c.).

Sign in / Sign up

Export Citation Format

Share Document