scholarly journals THE ROLE OF METHIONINE DEFICIENCY IN POLIOVIRUS REPLICATION IN TISSUE CULTURES

1966 ◽  
Vol 123 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Soussan Mohajer ◽  
Janis Gabliks
Keyword(s):  
Amino Acids ◽  
Hela Cells ◽  
Inhibitory Effect ◽  
Monkey Kidney ◽  
Kidney Cells ◽  
Tissue Cultures ◽  
Experimental Conditions ◽  
Methionine Deficiency ◽  
Intracellular Amino Acids

The role of methionine in poliovirus infection in HeLa and monkey kidney cells was investigated by using the methionine analogue l-ethionine. In the presence of 2.0 x 10–3 and 4.0 x 10–3 moles ethionine, the growth of HeLa and monkey kidney cells was significantly inhibited. Under the same experimental conditions, ethionine had no significant effect on the biosynthesis of two strains of poliovirus (Mahoney and Lansing) in HeLa cells, whereas in primary monkey kidney cells, it markedly inhibited the biosynthesis of the Lansing strain of poliovirus. HeLa cells partly depleted of their intracellular amino acids did not change the rate of viral biosynthesis. The inhibitory effect of ethionine on cell growth and viral biosynthesis was reversed by addition of an excess of l-methionine.

scholarly journals Enterovirus 70 Receptor Utilization Is Controlled by Capsid Residues That Also Regulate Host Range and Cytopathogenicity

2007 ◽  
Vol 81 (16) ◽  
pp. 8648-8655 ◽  
Author(s):  
Melissa Stewart Kim ◽  
Vincent R. Racaniello
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rhesus Monkey ◽  
Host Range ◽  
Hela Cells ◽  
Lytic Replication ◽  
Monkey Kidney ◽  
Kidney Cells ◽  
Cytopathic Effects ◽  
Axis Of Symmetry

ABSTRACT Enterovirus type 70, an etiologic agent of acute hemorrhagic conjunctivitis, may bind different cellular receptors depending on cell type. To understand how EV70-receptor interaction is controlled, we studied two variants of the virus with distinct receptor utilization. EV70-Rmk, derived by passage in rhesus monkey kidney cells, replicates poorly in HeLa cells and does not cause cytopathic effects. Decay accelerating factor (DAF) is not a cell receptor for EV70-Rmk. Passage of EV70-Rmk in HeLa cells lead to isolation of EV70-Dne, which does not replicate in rhesus monkey kidney cells but grows to high titers in HeLa cells and causes cytopathic effects. DAF is sufficient for cell entry of EV70-Dne. EV70-Rmk replicates in human eye and brain-derived cell lines, whereas the Dne strain replicates only in HeLa cells and in conjunctiva-derived 15C4 cells. The two EV70 strains differ by five amino acid changes in the viral capsid. Single substitution of four of the five EV70-Rmk amino acids with the residue from EV70-Dne leads to lytic replication in HeLa cells. Conversely, substitution of any of the five EV70-Dne amino acids with the EV70-Rmk amino acid does not alter replication in HeLa cells. Three of these capsid amino acids are predicted to be located in the canyon encircling the fivefold axis of symmetry, one amino acid is found at the fivefold axis of symmetry, and one is located the interior of the capsid. The five EV70 residues define a region of the capsid that controls viral host range, DAF utilization, and cytopathogenicity.

Studies on regulatory mechanisms of heme biosynthesis in hepatocytes from normal and experimental-diabetic rats. Role of insulin

1990 ◽  
Vol 68 (6) ◽  
pp. 914-921 ◽  
Author(s):  
Eduardo T. Cánepa ◽  
Elena B. C. Llambías ◽  
Moisés Grinstein
Keyword(s):  
Aminolevulinic Acid ◽  
Rat Hepatocytes ◽  
Isolated Hepatocytes ◽  
Inhibitory Effect ◽  
Diabetic Rats ◽  
Significant Inhibition ◽  
Diabetic Rat ◽  
Experimental Conditions ◽  
Cytochrome P 450

In the present work we demonstrate that insulin decreases the phenobarbital-induced activities of δ-aminolevulinic acid synthase and ferrochelatase in isolated hepatocytes from normal and experimental-diabetic rats. Insulin concentrations required to produce significant inhibition in diabetic hepatocytes were higher than in normal cells. Under similar experimental conditions, insulin decreased the basal activities of δ-aminolevulinic acid synthase and ferrochelatase in hepatocytes from normal rats; no inhibitory effect was observed on the basal activity of δ-aminolevulinic acid synthase in hepatocytes from diabetic rats. Cytochrome P-450 content of both normal and diabetic cells was not affected by insulin in absence or presence of phenobarbital. The inhibitory action of insulin was exerted even when effective concentrations of glucagon, dexamethasone, or 8-(p-chlorophenylthio)-cAMP were present.Key words: δ-aminolevulinic acid synthase, ferrochelatase, cAMP, insulin, diabetic rat hepatocytes.

scholarly journals A comparative study of susceptibility of primary monkey kidney cells, Hep 2 cells and HeLa cells to a variety of faecal viruses

1963 ◽  
Vol 61 (4) ◽  
pp. 493-498 ◽  
Author(s):  
S. R. Pal ◽  
J. McQuillin ◽  
P. S. Gardner
Keyword(s):  
Comparative Study ◽  
Cell Line ◽  
Hela Cells ◽  
Monkey Kidney ◽  
Clinical Material ◽  
Kidney Cells ◽  
Better Than

A comparative study of the susceptibility of monkey kidney, Hep 2 and HeLa cells to enteroviruses and adenoviruses is made. It seems that this Hep 2 cell line is as effective as the monkey kidney cells in their susceptibility to vaccine strains of polioviruses and far better than monkey kidney cells in their susceptibility to strains of ECHO 6 and ECHO 11 from clinical material. It is as effective as, or slightly better than, HeLa cells for the isolation of adenoviruses. It also compares favourably with monkey kidney cells for the isolation of other enteroviruses.We are most grateful to Glaxo Laboratories Ltd. for the supplies of monkey kidney cells used in this investigation.

scholarly journals Classical swine fever virus NS5B protein suppresses the inhibitory effect of NS5A on viral translation by binding to NS5A

2012 ◽  
Vol 93 (5) ◽  
pp. 939-950 ◽  
Author(s):  
Chun Sheng ◽  
Jing Wang ◽  
Jing Xiao ◽  
Jun Xiao ◽  
Yan Chen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Classical Swine Fever Virus ◽  
Classical Swine Fever ◽  
Inhibitory Effect ◽  
Fever Virus ◽  
Viral Translation ◽  
Ns5a Protein ◽  
Gdd Motif ◽  
Ns5b Protein

In order to investigate molecular mechanisms of internal ribosome entry site (IRES)-mediated translation in classical swine fever virus (CSFV), an important pathogen of pigs, the expression level of NS3 was evaluated in the context of genomic RNAs and reporter RNA fragments. All data showed that the NS5A protein has an inhibitory effect on IRES-mediated translation and that NS5B proteins suppress the inhibitory effect of NS5A on viral translation, but CSFV NS5B GDD mutants do not. Furthermore, glutathione S-transferase pull-down assay and immunoprecipitation analysis, associated with deletion and alanine-scanning mutations, were performed. Results showed that NS5B interacts with NS5A and that the region aa 390–414, located in the C-terminal half of NS5A, is important for binding of NS5B to NS5A. Furthermore, amino acids K399, T401, E406 and L413 in the region were found to be essential for NS5A–NS5B interaction, virus rescue and infection. The above-mentioned region and four amino acids were observed to overlap with the site responsible for inhibition of IRES-mediated translation by the NS5A protein. We also found that aa 63–72, aa 637–653 and the GDD motif of NS5B were necessary for the interaction between NS5A and NS5B. These findings suggest that the repression activity of the NS5B protein toward the role of NS5A in translation might be achieved by NS5A–NS5B interaction, for which aa 390–414 of NS5A and aa 63–72, aa 637–653 and the GDD motif of NS5B are indispensable. This is important for understanding the role of NS5A–NS5B interaction in the virus life cycle.

scholarly journals NMR Based Real-Time Enzyme Kinetics on Estimating the Inhibitory Effect of Sucralose in the Enzymatic Conversion of Sucrose

2020 ◽  
Author(s):  
Justin Vang ◽  
Cheenou Her ◽  
Krish Krishnan
Keyword(s):  
Enzyme Kinetics ◽  
Real Time ◽  
Potent Inhibitor ◽  
Inhibitory Effect ◽  
Lambert W Function ◽  
Enzymatic Conversion ◽  
Experimental Conditions ◽  
Enzymatic Production ◽  
Progress Curve

<p>Sucralose, one of the popular non-caloric artificial sweeteners, has been known to influence the enzymatic conversion of sucrose to glucose and fructose by invertase. In continuing the use of real-time NMR experiments and reaction progress curve analysis to measure enzyme kinetics, here we investigate the role of sucralose as an inhibitor. NMR based kinetic experiments were performed as a function of the substrate concentration for a range of sucralose concentrations, and the results were analyzed by fitting the progress curve to the Lambert-W function. The Michaelis-Menten parameters were then used to estimate the inhibitory constant of sucralose. To estimate the extent of sucralose inhibition on the enzymatic production of glucose, control experiments were performed with lactose as the inhibitor under similar experimental conditions. The results show that sucralose is a much more potent inhibitor than lactose, inhibiting the enzymatic conversion at least seven times more. <b><u></u></b></p>

NEW VIRAL AGENTS RECOVERED FROM TISSUE CULTURES OF MONKEY KIDNEY CELLS

1956 ◽  
Vol 63 (2) ◽  
pp. 204-215 ◽  
Author(s):  
ROBERT N. HULL ◽  
JAMES R. MINNER ◽  
JAMES W. SMITH
Keyword(s):  
Monkey Kidney ◽  
Kidney Cells ◽  
Tissue Cultures

scholarly journals Intracellular amino acids and protein synthesis in Hela cells

1973 ◽  
Vol 1 (3) ◽  
pp. 167-171 ◽  
Author(s):  
Walther J. van venrooij ◽  
Lucy van Loon-Klaassen
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Hela Cells ◽  
Intracellular Amino Acids

Physiological role of glucocorticoids on rat serum and liver metallothionein in basal and stress conditions

1988 ◽  
Vol 254 (1) ◽  
pp. E71-E78
Author(s):  
J. Hidalgo ◽  
M. Giralt ◽  
J. S. Garvey ◽  
A. Armario
Keyword(s):  
Metal Binding ◽  
Physiological Role ◽  
Inhibitory Effect ◽  
Experimental Conditions ◽  
Rat Serum ◽  
Ru 486 ◽  
Positive Effect ◽  
Permissive Role

Serious contradictions exist at present in our understanding of the physiological role of glucocorticoids on the synthesis of the metal-binding protein, metallothionein (MT). In addressing this problem, we have examined in vivo the role of glucocorticoids on liver and serum MT levels in the rat under a spectrum of experimental conditions. The experiments confirm that stress has a major positive effect on hepatic MT levels. It was found that adrenocorticotropic hormone (ACTH) administration has an inhibitory effect on hepatic MT levels in response to restraint stress and that adrenalectomy (ADX) leads to an increase in basal MT levels and in MT levels in response to acute and chronic immobilization stress. Similar results followed treatment with the glucocorticoid receptor blocker, RU 486. The effect of ADX was abolished by corticosterone replacement. The relations found among hepatic MT, serum MT, and glucocorticoid concentrations indicate that in some circumstances glucocorticoids have a permissive role in mobilizing MT from tissues to serum and that in physiological conditions corticosterone has an inhibitory role in the maintenance of hepatic MT levels.

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