scholarly journals SUPPRESSION OF DELAYED HYPERSENSITIVITY IN VITRO BY INHIBITION OF PROTEIN SYNTHESIS

1965 ◽  
Vol 122 (6) ◽  
pp. 1125-1134 ◽  
Author(s):  
John R. David
Keyword(s):  
Protein Synthesis ◽  
Culture Medium ◽  
Specific Antigen ◽  
Delayed Hypersensitivity ◽  
Cell Protein ◽  
Sensitive Cell ◽  
Active Protein ◽  
Inhibit Protein Synthesis ◽  
Inhibition Of Protein Synthesis

Peritoneal cells from guinea pigs exhibiting delayed hypersensitivity are inhibited from migrating in vitro by specific antigen. This inhibition is prevented by the addition of puromycin to the culture medium. The amount of puromycin necessary to prevent the inhibition by antigen also suppressed the incorporation of C14-leucine into peritoneal cell protein. Additional evidence that the action of puromycin is due to its inhibition of protein synthesis has been obtained with analogues of puromycin; those that inhibit protein synthesis also prevent the action of antigen on the cells, while those analogues that do not inhibit protein synthesis have no effect. Actinomycin also prevents the inhibition of sensitive cells by antigen while chloramphenicol has no effect. The data indicate that the inhibition of sensitive cell migration by antigen requires active protein synthesis. The possible mechanisms by which inhibition of protein synthesis may influence the in vitro reactions of delayed hypersensitivity are discussed.

The synthesis of a variant-specific antigen by Trypanosoma brucei in vitro

Parasitology ◽  
1977 ◽  
Vol 74 (1) ◽  
pp. 47-60 ◽  
Author(s):  
D. W. Taylor ◽  
G. A. M. Cross
Keyword(s):  
Protein Synthesis ◽  
Specific Surface ◽  
Trypanosoma Brucei ◽  
Specific Antigen ◽  
Defined Medium ◽  
Surface Coat ◽  
Chemically Defined Medium ◽  
Inhibit Protein Synthesis

A variant-specific surface antigen from a cloned population of Trypanosoma brucei S 42 has been isolated and partically characterized. [35S]L-methionine was found to be incorporated into this material by cells incubated in vitro in a chemically defined medium. Incorporation of [35S]L-methionine was inhibited by cycloheximide and puromycin at concentrations which are known to specifically inhibit protein synthesis in other systems. The rate of synthesis of the variant-specific antigen in vitro has been estimated to be about 8% of the rate in vivo. Newly synthesized [35S]L-methionine-labelled variant-specific antigen was incorporated into the surface coat.

Pituitary adenylate cyclase activating polypeptide can regulate testicular germ cell protein synthesis in vitro

1995 ◽  
Vol 144 (2) ◽  
pp. 215-223 ◽  
Author(s):  
A P West ◽  
C McKinnell ◽  
R M Sharpe ◽  
P T K Saunders
Keyword(s):  
Protein Synthesis ◽  
Adenylate Cyclase ◽  
Germ Cell ◽  
Culture Medium ◽  
Secreted Proteins ◽  
Cell Protein ◽  
Testicular Germ Cell ◽  
Pituitary Adenylate Cyclase ◽  
Intracellular Proteins

Abstract The aim of this study was to explore whether pituitary adenylate cyclase activating polypeptide (PACAP) could regulate protein synthesis by enriched preparations of spermatocytes and spermatids from the adult rat testis. Spermatocytes and spermatids were incubated for 8 h or 24 h in the absence (control) or presence of PACAP-27, PACAP-38, vasoactive intestinal peptide (VIP) or dibutyryl adenosine-3′,5′-cyclic monophosphate (db-cAMP). Total synthesis of intracellular and secreted proteins, during the incubation periods, was assessed and selected samples were analysed by 2-D SDS-PAGE. PACAP-38 (200 nm), VIP (200 nm) and db-cAMP (1 mm) significantly increased the synthesis of spermatocyte-secreted and intracellular proteins by 8 h and 24 h. Synthesis of both intracellular and secreted proteins by spermatids was significantly inhibited at 8 h and 24 h with PACAP, VIP and db-cAMP. The abundance of four germ cell-secreted proteins (GSP1, GSP2, GSP3 and phosphatidyethanolamine-binding protein (PEBP)), which can be identified in both spermatocyte and spermatid culture medium, and β-actin, which can only be identified in spermatid culture medium, was analysed. PACAP-38 and db-cAMP significantly increased the incorporation of label into GSP1, GSP2, GSP3 and PEBP, derived from spermatocyte culture medium, at 8 h and 24 h. In contrast PACAP-38 inhibited the incorporation of label into GSP1 and β-actin, derived from spermatid culture medium, at 24 h. The results show that PACAP can regulate synthesis of both secreted and intracellular proteins by spermatids and spermatocytes in vitro. This effect is mimicked with high doses of db-cAMP (>1 mm), suggesting that PACAP may act via a pathway that involves changes in cyclic AMP concentration in the germ cells. Journal of Endocrinology (1995) 144, 215–223

INHIBITION OF THYROGLOBULIN BIOSYNTHESIS AND DEGRADATION BY EXCESS IODIDE. SYNERGISM WITH LITHIUM

1976 ◽  
Vol 81 (2) ◽  
pp. 495-506 ◽  
Author(s):  
A. Radvila ◽  
R. Roost ◽  
H. Bürgi ◽  
H. Kohler ◽  
H. Studer
Keyword(s):  
Protein Synthesis ◽  
Thyroid Gland ◽  
Inhibitory Action ◽  
Inhibit Protein Synthesis ◽  
Thyrotrophic Hormone ◽  
Thyroid Glands ◽  
Pre Treatment ◽  
Excess Iodide ◽  
Kidney Liver

ABSTRACT Lithium and excess iodide inhibit the release of thyroid hormone from preformed stores. We thus tested the hypothesis that this was due to an inhibition of thyroglobulin breakdown. Rats were pre-treated with propylthiouracil (PTU) for 3 weeks in order to deplete their thyroids of thyroglobulin. While the PTU was continued, lithium chloride (0.25 mEq./100 g weight) or potassium iodide (3 mg per rat) were injected every 12 h for 3 days. Thereafter the thyroglobulin content in thyroid gland homogenates was measured. PTU pre-treatment lowered the thyroglobulin content from 4.21 to 0.22 mg/100 mg gland. Lithium caused a marked re-accumulation of thyroglobulin to 0.60 mg/100 mg within 3 days. While iodide alone had only a borderline effect, it markedly potentiated the action of lithium and a combination of the two drugs increased the thyroglobulin content to 1.04 mg/100 mg. Thyroxine was injected into similarly pre-treated animals to suppress secretion of thyrotrophic hormone. This markedly inhibited the proteolysis of thyroglobulin and 1.3 mg/100 mg gland accumulated after 3 days. Excess iodide, given in addition to thyroxine, decreased the amount of thyroglobulin accumulated to 0.75 mg/100 mg gland. To study whether this could be explained by an inhibitory action of iodide on thyroglobulin biosynthesis, thyroid glands from animals treated with excess iodide were incubated in vitro in the presence of 0.2 mm iodide for 3 h. Iodide decreased the incorporation of radioactive leucine into total thyroidal protein and into thyroglobulin by 25 and 35 % respectively. Iodide did not inhibit protein synthesis in the kidney, liver or muscle tissue. Thus, large doses of iodide selectively inhibit thyroglobulin biosynthesis.

scholarly journals ALTERATIONS OF MACROPHAGE FUNCTIONS BY MEDIATORS FROM LYMPHOCYTES

1971 ◽  
Vol 133 (6) ◽  
pp. 1356-1376 ◽  
Author(s):  
Carl F. Nathan ◽  
Manfred L. Karnovsky ◽  
John R. David
Keyword(s):  
Protein Synthesis ◽  
Cellular Immunity ◽  
Specific Antigen ◽  
Peritoneal Exudate ◽  
Chemotactic Factor ◽  
Hexose Monophosphate ◽  
Peritoneal Exudate Macrophages

Sensitized lymphocytes were incubated in vitro with the specific antigen Supernatants from these cultures were chromatographed on Sephadex G-100 columns. Supernatant fractions containing MIF, chemotactic factor, and lymphotoxin, but free of antigen and antibody, were incubated with normal peritoneal exudate macrophages. Macrophage adherence, phagocytosis, spreading, motility, and direct hexose monophosphate oxidation were enhanced, while protein synthesis was unaffected. Thus, antigen-stimulated lymphocytes secrete a factor or factors which enhance certain macrophage functions. Implications for models of cellular immunity and cellular hypersensitivity are discussed.

The effect of osmolarity on mouse parthenogenesis

Development ◽  
1974 ◽  
Vol 31 (2) ◽  
pp. 513-526
Author(s):  
M. H. Kaufman ◽  
M. A. H. Surani
Keyword(s):  
Protein Synthesis ◽  
Culture Medium ◽  
Culture Media ◽  
Polar Body ◽  
Amino Acid Mixture ◽  
Culture Conditions ◽  
Follicle Cells ◽  
Acid Mixture ◽  
Second Polar Body

Eggs from (C57B1 × A2G)F1 mice were activated by treatment with hyaluronidase, which removed the follicle cells, and cultured in vitro. Observations were made 6–8 h after hyaluronidase treatment to determine the frequency of activation and the types of parthenogenones induced. Cumulus-free eggs resulting from hyaluronidase treatment were incubated for 2¼ h in culture media of various osmolarities. The frequency of activation was found to be dependent on the postovulatory age of oocytes, while the types of parthenogenones induced were dependent on the osmolarity of the in vitro culture medium and their postovulatory age. Culture in low osmolar medium suppressed the extrusion of the second polar body (2PB). This decreased the incidence of haploid eggs with a single pronucleus and 2PB and immediately cleaved eggs from 97·5% to 42·3% of the activated population. Where 2PB extrusion had been suppressed, 97·4% of parthenogenones contained two haploid pronuclei. Very few were observed with a single and presumably diploid pronucleus. Serial observations from 11 to 18 h after hyaluronidase treatment were made on populations of activated eggs as they entered the first cleavage mitosis after 2¼ h incubation in medium either of normal (0·287 osmol) or low (0·168 osmol) osmolarity. A delay in the time of entry into the first cleavage mitosis similar to the duration of incubation in low osmolar medium was observed. Further, eggs were incubated in control and low osmolar culture media containing uniformly labelled [U-14C]amino acid mixture to examine the extent of protein synthesis in recently activated eggs subjected to these culture conditions. An hypothesis is presented to explain the effect of incubation in low osmolar culture medium in delaying the first cleavage mitosis.

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