RNA and protein synthesis in chick embryo lung cell monolayer cultures infected with influenza virus

1970 ◽  
Vol 30 (4) ◽  
pp. 367-378 ◽  
Author(s):  
R. Borland ◽  
B. W. J. Mahy
Keyword(s):  
Protein Synthesis ◽  
Influenza Virus ◽  
Chick Embryo ◽  
Cell Monolayer ◽  
Monolayer Cultures ◽  
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.

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 STUDIES ON INFLUENZA VIRUS

1941 ◽  
Vol 73 (5) ◽  
pp. 581-599 ◽  
Author(s):  
Edwin H. Lennette ◽  
Frank L. Horsfall
Keyword(s):  
Influenza Virus ◽  
Chick Embryo ◽  
Influenza A Virus ◽  
Influenza A ◽  
Complement Fixation ◽  
Soluble Antigen ◽  
Swine Virus ◽  
Specific Fixation ◽  
Mouse Lungs

Influenza complement fixation tests designed for use with ferret serum are described. Complement-fixing antigens derived from influenza ferret lungs were unsatisfactory due to their low content of soluble antigen; those prepared from mouse lungs or developing chick embryo membranes proved to be better antigenically and were reliable when the various reagents in the test were properly adjusted to eliminate non-specific fixation of complement. The results of cross complement fixation tests indicated that the soluble antigens of the PR8 and W.S. strains of influenza A virus were closely similar, if not identical. They indicated also that the soluble antigen of swine virus possessed components present in the antigens of the human strains of virus.

Sign in / Sign up

Export Citation Format

Share Document