scholarly journals CHEMICAL STUDIES ON HOST-VIRUS INTERACTIONS

1947 ◽  
Vol 85 (6) ◽  
pp. 771-784 ◽  
Author(s):  
Seymour S. Cohen ◽  
Catherine B. Fowler
Keyword(s):  
Latent Period ◽  
Virus Multiplication ◽  
Killing Effect ◽  
Chemical Studies ◽  
Host Virus Interactions ◽  
Virus Interactions

The inhibition of virus multiplication by 5-methyl tryptophane can be specifically reversed by tryptophane. The conditions of reversal indicate that 5MT specifically interferes with tryptophane utilization. The tryptophane requirements of virus multiplication appear to exist throughout the latent period and determine the time of lysis and amount of virus liberated. A latent period may be interrupted for 15 minutes or more and be resumed on addition of tryptophane. Extended inhibition with 5MT results in a somewhat variable "killing" effect, the extent of which determines aspects of the reversal of the inhibition by tryptophane. The implications of these phenomena have been discussed.

scholarly journals CHEMICAL STUDIES IN HOST-VIRUS INTERACTIONS

1948 ◽  
Vol 87 (4) ◽  
pp. 275-282 ◽  
Author(s):  
Seymour S. Cohen ◽  
Catherine B. Fowler
Keyword(s):  
Virus Production ◽  
Acid Synthesis ◽  
Defined Medium ◽  
Virus Growth ◽  
Chemical Studies ◽  
One Step ◽  
Growth Promoting ◽  
The One ◽  
Host Virus Interactions ◽  
Virus Interactions

Omission of a single constituent from a chemically defined medium approximating the virus growth-promoting properties of broth affects virus production in infected bacteria. This may be estimated by the one-step growth technique and the course of desoxyribose nucleic acid synthesis. Nine amino acids and one purine have been shown to be important by these tests. A combination of all constituents observed to be important by the single supplement and single omission techniques has approximated the virus growth-promoting properties of broth. Certain anomalous results have been commented upon.

scholarly journals CHEMICAL STUDIES ON HOST-VIRUS INTERACTIONS

1946 ◽  
Vol 84 (5) ◽  
pp. 525-533 ◽  
Author(s):  
Seymour S. Cohen ◽  
Thomas F. Anderson
Keyword(s):  
Synthetic Medium ◽  
Interference Effects ◽  
Oxygen Utilization ◽  
E Coli ◽  
Chemical Studies ◽  
Bacterial Viruses ◽  
Host Virus Interactions ◽  
Virus Interactions

5-methyl tryptophane inhibited the multiplication of E. coli B without apparently affecting the rate of its oxygen utilization or R. Q. in a synthetic medium. E. coli B, under conditions of inhibition in the presence of this compound, was infected with the bacterial viruses T2 or T4. Infected organisms, in the presence of this compound, were unable to reproduce virus, assayable by the plaque method. Indeed, the number of infectious centers disappeared at a logarithmic rate in the presence of 5-methyl tryptophane, although the compound did not reduce the titers of B, T2, or T4, when the bacteria or viruses were exposed separately to the agent. In contrast to the irreversibility of the interference effects induced by viruses, the effects induced by short exposures to 5MT appear to be reversible on removal of the compound.

scholarly journals CHEMICAL STUDIES IN HOST-VIRUS INTERACTIONS

1948 ◽  
Vol 87 (4) ◽  
pp. 259-274 ◽  
Author(s):  
Catherine B. Fowler ◽  
Seymour S. Cohen
Keyword(s):  
Amino Acids ◽  
Burst Size ◽  
Host Cells ◽  
Simple Medium ◽  
Chemical Studies ◽  
One Step ◽  
Nutritional Environment ◽  
The One ◽  
Host Virus Interactions ◽  
Virus Interactions

Using the one-step growth technique the production of the virus T2 in its host, measured by latent period and burst size, was shown to depend on the nutritional environment of the host cell. When E. coli, grown in broth, was transferred to a simple medium, single organic compounds such as some amino acids and nucleosides were found to increase or accelerate the synthesis of virus. An antimetabolite of glutamic acid, an amino acid important for virus synthesis, was shown to be inhibitory. Several naturally occurring amino acids, leucine, serine, and cysteine, inhibited virus synthesis in the simple medium. A chemically defined mixture was found which supported a rate of virus synthesis very nearly comparable to that found for host cells in nutrient broth.

scholarly journals CHEMICAL STUDIES ON HOST-VIRUS INTERACTIONS

1946 ◽  
Vol 84 (5) ◽  
pp. 511-523 ◽  
Author(s):  
Seymour S. Cohen ◽  
Thomas F. Anderson
Keyword(s):  
Respiratory Rate ◽  
Cytoplasmic Granules ◽  
E Coli ◽  
T4 Bacteriophage ◽  
Chemical Studies ◽  
Host Virus Interactions ◽  
Virus Interactions ◽  
Relationship Of ◽  
The Relationship ◽  
Similar Substance

The addition of active or irradiated T2 bacteriophage and T4 bacteriophage to E. coli B stops bacterial multiplication. The respiratory rate and respiratory quotient of the inhibited bacteria remained at the values observed just before infection. A respiratory rate decrease which occasionally appears can be roughly correlated with change of turbidity of the suspension. An intracellular inhibitor of multiplication appears to be liberated into lysates. A similar substance has been separated from normal E. coli B after sonic disintegration. These bacteriostatic preparations contain cytoplasmic granules with lactic acid dehydrogenase activity. The relationship of these phenomena to the interference effect in this system and others has been considered.

scholarly journals CHEMICAL STUDIES IN HOST-VIRUS INTERACTIONS

1950 ◽  
Vol 91 (6) ◽  
pp. 607-618 ◽  
Author(s):  
Seymour S. Cohen ◽  
Rachel Arbogast
Keyword(s):  
Nucleic Acid ◽  
Differential Centrifugation ◽  
Host Organism ◽  
Constituent Part ◽  
E Coli ◽  
Virus Activity ◽  
Chemical Studies ◽  
Bacterial Viruses ◽  
Host Virus Interactions ◽  
Virus Interactions

Three mutant pairs of bacterial viruses T2r+ and T2r, T4r+ and T4r, T6r+ and T6r, have been concentrated by differential centrifugation and analyzed. Under conditions of prolonged lysis of organisms grown on broth-agar, the virus concentrates frequently contained phosphorus (P) other than that contained in desoxyribose nucleic acid (DNA). These concentrates reacted with antisera to the host organism, E. coli, specifically precipitating the non-DNA-P but not virus activity or DNA. The amounts of nitrogen precipitated in the virus concentrates by antisera were related to their content of non-DNA-P. These viruses could be purified by differential centrifugation after such treatment to yield preparations apparently free of P other than DNA-P. It has been concluded that there is no satisfactory evidence for the presence of ribose nucleic acid as a constituent part of these viruses.

scholarly journals CHEMICAL STUDIES IN HOST-VIRUS INTERACTIONS

1950 ◽  
Vol 91 (6) ◽  
pp. 619-636 ◽  
Author(s):  
Seymour S. Cohen ◽  
Rachel Arbogast
Keyword(s):  
Growth Curves ◽  
Multiple Infection ◽  
Chemical Studies ◽  
One Step ◽  
Infected Cells ◽  
Dna And Protein Synthesis ◽  
The One ◽  
Reproductive Cycles ◽  
Host Virus Interactions ◽  
Virus Interactions

Various chemical and physiological aspects of the reproductive cycles of r+ and r strains of T2, T4, and T6 viruses have been examined and compared. These include the ultraviolet absorption spectra in which differences between r and r+ strains were not observed, though they were obtained in the case of T2, T4, and T6. Adsorption of T4 and T6 was found to require the adsorption cofactor l-tryptophane. Among the r and r+ strains of these viruses limiting tryptophane requirements for adsorption were found to be different. Some differences were observed in the one-step growth curves of these viruses under conditions of single and multiple infection. The turbidity-time relations of infected cultures were characteristically different. The rates of DNA and protein synthesis in the infected cells were found to be independent of the viruses used. Certain implications of the data have been discussed.

scholarly journals The molecular footprints of COVID-19

2020 ◽  
Vol 45 (3) ◽  
pp. 241-248
Author(s):  
Engin Yilmaz ◽  
Yakut Akyön ◽  
Muhittin Serdar
Keyword(s):  
Reaction Time ◽  
Changing Environment ◽  
The Third ◽  
The Past ◽  
The People ◽  
The World ◽  
The Future ◽  
Host Virus Interactions ◽  
Virus Interactions

AbstractCOVID-19 is the third spread of animal coronavirus over the past two decades, resulting in a major epidemic in humans after SARS and MERS. COVID-19 is responsible of the biggest biological earthquake in the world. In the global fight against COVID-19 some serious mistakes have been done like, the countries’ misguided attempts to protect their economies, lack of international co-operation. These mistakes that the people had done in previous deadly outbreaks. The result has been a greater economic devastation and the collapse of national and international trust for all. In this constantly changing environment, if we have a better understanding of the host-virus interactions than we can be more prepared to the future deadly outbreaks. When encountered with a disease which the causative is unknown, the reaction time and the precautions that should be taken matters a great deal. In this review we aimed to reveal the molecular footprints of COVID-19 scientifically and to get an understanding of the pandemia. This review might be a highlight to the possible outbreaks.

scholarly journals Poxviral Strategies to Overcome Host Cell Apoptosis

Pathogens ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Chathura D. Suraweera ◽  
Mark G. Hinds ◽  
Marc Kvansakul
Keyword(s):  
Viral Infections ◽  
B Cell Lymphoma ◽  
Intrinsic Apoptosis ◽  
Host Cell Apoptosis ◽  
Successful Infection ◽  
Infected Cells ◽  
Host Virus Interactions ◽  
Almost All ◽  
Virus Interactions ◽  
Multicellular Organisms

Apoptosis is a form of cellular suicide initiated either via extracellular (extrinsic apoptosis) or intracellular (intrinsic apoptosis) cues. This form of programmed cell death plays a crucial role in development and tissue homeostasis in multicellular organisms and its dysregulation is an underlying cause for many diseases. Intrinsic apoptosis is regulated by members of the evolutionarily conserved B-cell lymphoma-2 (Bcl-2) family, a family that consists of pro- and anti-apoptotic members. Bcl-2 genes have also been assimilated by numerous viruses including pox viruses, in particular the sub-family of chordopoxviridae, a group of viruses known to infect almost all vertebrates. The viral Bcl-2 proteins are virulence factors and aid the evasion of host immune defenses by mimicking the activity of their cellular counterparts. Viral Bcl-2 genes have proved essential for the survival of virus infected cells and structural studies have shown that though they often share very little sequence identity with their cellular counterparts, they have near-identical 3D structures. However, their mechanisms of action are varied. In this review, we examine the structural biology, molecular interactions, and detailed mechanism of action of poxvirus encoded apoptosis inhibitors and how they impact on host–virus interactions to ultimately enable successful infection and propagation of viral infections.

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