scholarly journals NUCLEIC ACID SYNTHESIS IN TYPES 4 AND 5 ADENOVIRUS-INFECTED HELA CELLS

1961 ◽  
Vol 113 (2) ◽  
pp. 283-299 ◽  
Author(s):  
Harold S. Ginsberg ◽  
Mary K. Dixon
Keyword(s):  
Viral Infection ◽  
Hela Cells ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Fold Increase ◽  
Sodium Formate ◽  
Acid Synthesis ◽  
Water Soluble ◽  
Viral Propagation ◽  
Infected Cells

Type 4 adenovirus infection of HeLa cells effected a marked increase in synthesis of the saline-soluble DNA fraction, but not the host-cell DNA (the water-soluble fraction). This was demonstrated by the marked increase in specific activity of saline-soluble DNA but not water-soluble DNA when P32-inorganic phosphate or sodium formate-C14 was employed. When these isotopes were used to label cells before viral infection rather than during the process of viral propagation, the saline-soluble DNA from infected cells had a specific activity of 10 to 20 per cent less than that of uninfected cells, indicating that the saline-soluble DNA was synthesized both from prelabeled precursors of the cell pools and unlabeled materials from the medium. Saline-soluble DNA began to increase between 10 to 12 hours after viral infection and 3 to 4 hours before appearance of newly propagated infectious virus. The specific activity of the acid-soluble pool of infected cells also increased between 10 to 12 hours after viral inoculation when sodium formate-C14 was used as a radioisotope. When P32-inorganic phosphate was utilized, the specific activity of infected-cell RNA was increased approximately the same relative amount as when total RNA was determined chemically; i.e., 30 to 40 per cent. With type 5 adenovirus, not only did a 3- to 5-fold increase in saline-soluble DNA occur, but also an increase was measured in specific activity of RNA when P32-inorganic phosphate was used.

PHOSPHORYLATION OF DIGLYCERIDES BY RAT BRAIN

1962 ◽  
Vol 40 (2) ◽  
pp. 247-259 ◽  
Author(s):  
K. P. Strickland
Keyword(s):  
Phosphatidic Acid ◽  
Rat Brain ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Alkaline Treatment ◽  
Water Soluble ◽  
Two Dimensional ◽  
Relative Specific Activity ◽  
Hydrolysis Products ◽  
Stimulation Of

The addition of D-α,β-dimyristin was observed to stimulate by three to six times the labelling of phospholipids from radioactive inorganic phosphate (Pi32) by glycolysing homogenates and respiring mitochondria of rat brain. The increase in labelling was confined to the glycerophosphate (GP) isolated by two-dimensional chromatography from the water-soluble hydrolysis products obtained on weak alkaline treatment of the labelled phospholipids. The GP formed under these conditions is presumed to be derived mainly from phosphatidic acid formed by the phosphorylation of the diglyceride. A similar effect was observed for D-α,β-dipalmitin, D-α,β-diolein, and natural diglycerides prepared from either egg lecithin or spinal cord lecithin, but not for D-α-β-distearin. L-α,β-Diolein was much less effective than the D-isomer, suggesting a stereospecificity on the part of the enzymic phosphorylation of diglyceride. Experiments on the effects of the omission of Mg++ and the addition of glycolytic inhibitors on the stimulation of the labelling from Pi32 caused by D-α,β-dimyristin and D-α,β-diolein in the anaerobic homogenate system suggested that the increased phosphorylation caused by added diglycerides was closely coupled to active glycolysis. A comparison of the relative specific activity of the lipid P, following incubation of Pi32 and ATP32 in the anaerobic homogenate system inhibited by fluoride with and without D-α,β-diolein added, showed that the phosphate of the newly formed phosphatidic acid was derived from ATP, suggesting the presence of a D-α,β-diglyceride kinase.

scholarly journals Computational and Transcriptome Analyses Revealed Preferential Induction of Chemotaxis and Lipid Synthesis by SARS-CoV-2

Biology ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 260 ◽  
Author(s):  
Hibah Shaath ◽  
Nehad M. Alajez
Keyword(s):  
Immune Response ◽  
Severe Acute Respiratory Syndrome ◽  
Viral Infection ◽  
Noncoding Rna ◽  
Immune Cell ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Lung Epithelial Cells ◽  
Cell Trafficking ◽  
Infected Cells

The continuous and rapid emergence of new viral strains calls for a better understanding of the fundamental changes occurring within the host cell upon viral infection. In this study, we analyzed RNA-seq transcriptome data from Calu-3 human lung epithelial cells infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) compared to five other viruses namely, severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East Respiratory Syndrome (SARS-MERS), influenzavirus A (FLUA), influenzavirus B (FLUB), and rhinovirus (RHINO) compared to mock-infected cells and characterized their coding and noncoding RNA transcriptional portraits. The induction of interferon, inflammatory, and immune response was a hallmark of SARS-CoV-2 infection. Comprehensive bioinformatics revealed the activation of immune response and defense response to the virus as a common feature of viral infection. Interestingly however, the degree of functional categories and signaling pathways activation varied among different viruses. Ingenuity pathways analysis highlighted altered conical and casual pathways related to TNF, IL1A, and TLR7, which are seen more predominantly during SARS-CoV-2 infection. Nonetheless, the activation of chemotaxis and lipid synthesis was prominent in SARS-CoV-2-infected cells. Despite the commonality among all viruses, our data revealed the hyperactivation of chemotaxis and immune cell trafficking as well as the enhanced fatty acid synthesis as plausible mechanisms that could explain the inflammatory cytokine storms associated with severe cases of COVID-19 and the rapid spread of the virus, respectively.

scholarly journals Induction of human choriogonadotropin in HeLa-cell cultures by aliphatic monocarboxylates and inhibitors of deoxyribonucleic acid synthesis

1977 ◽  
Vol 166 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Nimai K. Ghosh ◽  
Adriana Rukenstein ◽  
Rody P. Cox
Keyword(s):  
Protein Synthesis ◽  
Hela Cell ◽  
Dna Synthesis ◽  
Hela Cells ◽  
Fold Increase ◽  
Short Chain Fatty Acids ◽  
Acid Synthesis ◽  
Hydroxyl Groups ◽  
Β Subunit ◽  
Inhibitor Of Protein Synthesis

The ectopic production of the glycopeptide hormone human placental choriogonadotropin by HeLa65 cells was measured by radioimmunoassay with antiserum against the β-subunit of choriogonadotropin and with the125I-labelled β-subunit as a tracer antigen. Choriogonadotropin synthesis was markedly (500-fold) stimulated by sodium butyrate. Kinetic studies and the use of an inhibitor of protein synthesis, cycloheximide, indicated that protein synthesis was required for this induction. Investigation of the efficiency of 22 aliphatic short-chain fatty acids and derivatives in causing increased choriogonadotropin synthesis by HeLa cells showed stringent structural requirements. Induction of choriogonadotropin synthesis in HeLa cells was not restricted to butyrate. Other aliphatic acids (propionate, isobutyrate, valerate and hexanoate) were also capable of inducing choriogonadotropin synthesis at 10–50% of the efficiency of butyrate. Hydroxy derivatives of monocarboxylate inducers, related mono- and di-carboxylic acids, alcohols, amines, ketones, esters and sulphoxide were ineffective in increasing choriogonadotropin production by HeLa cells. A saturated C4 straight-chain acid without substituent hydroxyl groups but with a methyl group at one end and a carboxyl moiety at the other appeared to be most efficient in activating choriogonadotropin production. A second clonal line of HeLa cells, HeLa71, showed a higher constitutive synthesis of choriogonadotropin than HeLa65 cells, which was also markedly increased by butyrate. Butyrate and other aliphatic monocarboxylate inducers of choriogonadotropin synthesis inhibited HeLa-cell growth and DNA synthesis. This inhibition of DNA replication may be related to the mechanism of choriogonadotropin synthesis, since two well-characterized anti-neoplastic inhibitors of DNA synthesis, hydroxyurea and 1-β-d-arabinofuranosylcytosine, also stimulated a 300-fold increase in choriogonadotropin synthesis in HeLa cells and were synergistic with butyrate in promoting choriogonadotropin synthesis. Thus activation in tumour cells of genes normally expressed by foetal tissue and the consequent ectopic synthesis of polypeptide hormones may require neither cell division nor DNA synthesis.

PHOSPHORYLATION OF DIGLYCERIDES BY RAT BRAIN

1962 ◽  
Vol 40 (1) ◽  
pp. 247-259 ◽  
Author(s):  
K. P. Strickland
Keyword(s):  
Phosphatidic Acid ◽  
Rat Brain ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Alkaline Treatment ◽  
Water Soluble ◽  
Two Dimensional ◽  
Relative Specific Activity ◽  
Hydrolysis Products ◽  
Stimulation Of

The addition of D-α,β-dimyristin was observed to stimulate by three to six times the labelling of phospholipids from radioactive inorganic phosphate (Pi32) by glycolysing homogenates and respiring mitochondria of rat brain. The increase in labelling was confined to the glycerophosphate (GP) isolated by two-dimensional chromatography from the water-soluble hydrolysis products obtained on weak alkaline treatment of the labelled phospholipids. The GP formed under these conditions is presumed to be derived mainly from phosphatidic acid formed by the phosphorylation of the diglyceride. A similar effect was observed for D-α,β-dipalmitin, D-α,β-diolein, and natural diglycerides prepared from either egg lecithin or spinal cord lecithin, but not for D-α-β-distearin. L-α,β-Diolein was much less effective than the D-isomer, suggesting a stereospecificity on the part of the enzymic phosphorylation of diglyceride. Experiments on the effects of the omission of Mg++ and the addition of glycolytic inhibitors on the stimulation of the labelling from Pi32 caused by D-α,β-dimyristin and D-α,β-diolein in the anaerobic homogenate system suggested that the increased phosphorylation caused by added diglycerides was closely coupled to active glycolysis. A comparison of the relative specific activity of the lipid P, following incubation of Pi32 and ATP32 in the anaerobic homogenate system inhibited by fluoride with and without D-α,β-diolein added, showed that the phosphate of the newly formed phosphatidic acid was derived from ATP, suggesting the presence of a D-α,β-diglyceride kinase.

scholarly journals DEOXYRIBONUCLEIC ACID (DNA) AND PROTEIN ALTERATIONS IN HELA CELLS INFECTED WITH TYPE 4 ADENOVIRUS

1959 ◽  
Vol 109 (4) ◽  
pp. 407-422 ◽  
Author(s):  
Harold S. Ginsberg ◽  
Mary K. Dixon
Keyword(s):  
Hela Cells ◽  
High Speed ◽  
Marked Change ◽  
Fold Increase ◽  
Biochemical Alterations ◽  
Molar Ratios ◽  
Viral Particles ◽  
Infected Cells ◽  
Total Dna ◽  
Protein Alterations

During a single cycle of multiplication of type 4 adenovirus in HeLa cells an average 2-fold increase in total DNA occurred over that measured in uninfected cells. Of the total DNA from infected cells about 23 per cent was extractable into 0.15 M NaCl, a quantity approximately four and a half times greater than that of the DNA obtained from normal cells in 0.15 M NaCl. Ninety to 99 per cent of infectious virus was also extracted into the 0.15 M NaCl fraction. Concurrently with the accumulation of DNA in virus-infected cells there occurred a 2-fold increase in total protein. The proportionate increases in protein were approximately equal in 0.15 M NaCl and water extracts of infected cells. High speed centrifugation indicated that the bulk of the DNA and protein was not directly associated with infectious viral particles. Although in virus-infected cells a markedly increased synthesis occurred of a DNA which had solubility properties different from the major portion of normal host DNA, nucleotide analysis did not reveal any other qualitative differences. However, a marked change in nucleotide molar ratios was observed in the 0.15 M NaCl-soluble DNA from virus-infected cells. It seems apparent from the findings that the biochemical alterations found in HeLa cells infected with type 4 adenovirus are intimately related to the infectious process.

scholarly journals Regulation of Host Ribonucleic Acid Synthesis in Bacteriophage T3-infected Cells

1974 ◽  
Vol 249 (6) ◽  
pp. 1787-1791
Author(s):  
S.P. Mahadik ◽  
B. Dharmgrongartama ◽  
P.R. Srinivasan
Keyword(s):  
Ribonucleic Acid ◽  
Acid Synthesis ◽  
Infected Cells

scholarly journals Modulation of lipid-synthesizing enzymes by insulin in differentiated ob17 adipose-like cells

1983 ◽  
Vol 214 (2) ◽  
pp. 443-449 ◽  
Author(s):  
P Grimaldi ◽  
C Forest ◽  
P Poli ◽  
R Negrel ◽  
G Ailhaud
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Specific Activity ◽  
Fatty Acid Synthetase ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Acetate Incorporation ◽  
Long Term Effects ◽  
Response Curves ◽  
Glycerol 3 Phosphate Dehydrogenase

ob17 cells convert into adipose-like cells when maintained in the presence of physiological concentrations of insulin and tri-iodothyronine. After this conversion, insulin removal from differentiated ob17 cells gives within 24-48 h a large decrease in fatty acid synthetase, glycerol 3-phosphate dehydrogenase and acid:CoA ligase activities, as well as in the rate of fatty acid synthesis determined by [14C]acetate incorporation into lipids. All parameters are restored by insulin addition to initial values within 24-48 h. Dose-response curves of insulin on the restoration of glycerol 3-phosphate dehydrogenase activity and of fatty acid synthesis give half-maximally effective concentrations close to 1 nM, in agreement with the affinity for insulin of the insulin receptors previously characterized in these cells. Immunotitration experiments indicate that the changes in the specific activity of fatty acid synthetase are due to parallel changes in the cellular enzyme content. Therefore the ob17 cell line should be a useful model to study the long-term effects of insulin on the modulation of lipid synthesis in adipose cells.

scholarly journals Thermostable glucose isomerase from psychrotolerant Streptomyces species

1970 ◽  
Vol 1 ◽  
pp. 6-10 ◽  
Author(s):  
Bidur Dhungel ◽  
Manoj Subedi ◽  
Kiran Babu Tiwari ◽  
Upendra Thapa Shrestha ◽  
Subarna Pokhrel ◽  
...  
Keyword(s):  
Specific Activity ◽  
Fold Increase ◽  
Glucose Isomerase ◽  
Enzyme Concentration ◽  
Maximal Velocity ◽  
Ph Optimum ◽  
Streptomyces Spp ◽  
Optimum Ph ◽  
Optimum Reaction ◽  
Sepharose 4B

Glucose isomerase (EC 5.3.1.5) was extracted from Streptomyces spp., isolated from Mt. Everest soil sample, and purified by ammonium sulfate fractionation and Sepharose-4B chromatography. A 7.1 fold increase in specific activity of the purified enzyme over crude was observed. Using glucose as substrate, the Michaelis constant (KM<) and maximal velocity (Vmax) were found to be 0.45M and 0.18U/mg. respectively. The optimum substrate (glucose) concentration, optimum enzyme concentration, optimum pH, optimum temperature, and optimum reaction time were 0.6M, 62.14μg/100μl, 6.9, 70ºC, and 30 minutes, respectively. Optimum concentrations of Mg2+ and Co2+ were 5mM and 0.5mM, respectively. The enzyme was thermostable with half-life 30 minutes at 100ºC.DOI: 10.3126/ijls.v1i0.2300 Int J Life Sci 1 : 6-10

Binding of 3-phosphoglycerate leads to both activation and stabilisation of ADP-glucose pyrophosphorylase from apple leaves

2005 ◽  
Vol 32 (9) ◽  
pp. 839
Author(s):  
Rui Zhou ◽  
Lailiang Cheng
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Enzyme Activity ◽  
Inorganic Phosphate ◽  
Thermal Inactivation ◽  
Specific Activity ◽  
Apple Leaves ◽  
Apparent Homogeneity ◽  
Adp Glucose Pyrophosphorylase ◽  
High Concentrations

Apple leaf ADP-glucose pyrophosphorylase was purified 1436-fold to apparent homogeneity with a specific activity of 58.9 units mg–1. The enzyme was activated by 3-phosphoglycerate (PGA) and inhibited by inorganic phosphate (Pi) in the ADPG synthesis direction. In the pyrophosphorolytic direction, however, high concentrations of PGA (> 2.5 mm) inhibited the enzyme activity. The enzyme was resistant to thermal inactivation with a T0.5 (temperature at which 50% of the enzyme activity is lost after 5 min incubation) of 52°C. Incubation with 2 mm PGA or 2 mm Pi increased T0.5 to 68°C. Incubation with 2 mm dithiothreitol (DTT) decreased T0.5 to 42°C, whereas inclusion of 2 mm PGA in the DTT incubation maintained T0.5 at 52°C. DTT-induced decrease in thermal stability was accompanied by monomerisation of the small subunits. Presence of PGA in the DTT incubation did not alter the monomerisation of the small subunits of the enzyme induced by DTT. These findings indicate that binding of PGA renders apple leaf AGPase with a conformation that is not only more efficient in catalysis but also more stable to heat treatment. The physiological significance of the protective effect of PGA on thermal inactivation of AGPase is discussed.

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