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Biomedical subjects

E Katz

Publications and source records attributed to E Katz.

At least 271 records · Page 15Linked to original sources
PubMed1975

Accumulation of delta-Aminolevulinic Acid and Its Relation to Chlorophyll Synthesis and Development of Plastid Structure in Greening Leaves.

Levulinic acid inhibited the greening of etiolated maize (Zea mays) and bean (Phaseolus vulgaris) leaves and caused accumulation of delta-aminolevulinic acid (ALA). ALA accumulation in maize was equivalent to the decrease in chlorophyll, over a wide range of experimental conditions. It was saturated at low light intensities and was not limited by the supply of substrates during the early hours of greening. During 20 hours in light, levulinic acid had little effect on the structural development of thylakoids in bundle sheath chloroplasts but significantly reduced the number and size of thylakoids in grana of mesophyll chloroplasts. Recrystallization of prolamellar bodies and their reformation was inhibited. Mitochondria appeared not to be affected.The accumulation of ALA in bean leaves differed from that in maize in regard to its time course and the effect of levulinic acid concentration and light intensity. The amount of ALA accumulated exceeded that expected from the degree of inhibition of chlorophyll synthesis. Levulinic acid caused abnormalities in the structural development of bean chloroplasts and marked swelling of mitochondria.Chloramphenicol and cycloheximide inhibited ALA accumulation, while inhibitors of RNA synthesis had no effect. The extent of inhibition depended on the time the inhibitor was applied during the greening process. The use of ALA accumulation as a tool for studying the control of chlorophyll synthesis is discussed.

Journal Article↗
PubMed1975

Isolation and characterization of a gamma-thiochromanone-4-thiosemicarbazone-resistant mutant of vaccinia virus.

gamma-Thiochromanone-4-thiosemicarbazone (TCT) inhibits the growth of vaccinia virus in BSCl cells by interfering with viral maturation. A mutant of the virus (TCT(R)) which is resistant to this drug was isolated. This mutant also exhibits resistance to another thiosemicarbazone related compound, isatin beta-thiosemicarbazone (IBT). There is a good correlation between the cross-resistance of the two mutants IBT(R) and TCT(R) to TCT and IBT, respectively, and the similar antipoxvirus activity of these two thiosemicarbazone-related compounds.

Benzopyrans↗
PubMed1975

Inhibition of the growth of hemadsorption 2 virus by three acyl derivatives of amino acids.

Three acyl derivatives of amino acids, dicarbobenzoxy-l-lysine sodium, carbobenzoxy-l-aspartic acid-beta-benzyl ester potassium, and N-3-phenylpropionyl-S-benzyl-l-cysteine potassium inhibit the growth of parainfluenza 1 (hemadsorption 2) virus. The growth of simian virus 40, vaccinia, poliomyelitis type 1, Semliki Forest, Eastern equine encephalitis, and Western equine encephalitis viruses was not affected by these compounds. Four other acyl derivatives of amino acids did not inhibit the growth of any of the viruses tested.

Amino Acids↗
PubMed1974

Synthesis of vaccinia virus polypeptides in the presence of hydroxyurea.

Hydroxyurea (5 x 10(-3) M) inhibits the development of vaccinia virus in HeLa cells early after infection and prevents the synthesis of viral deoxyribonucleic acid. In the presence of hydroxyurea, late viral polypeptides are not formed, as observed by electrophoresis on polyacrylamide gels.

DNA, Viral↗