Iron-binding catechols and virulence in Escherichia coli.

A comparison of viral-induced unresponsiveness of phytohemagglutinin (PHA)-induced deoxyribonucleic acid (DNA) synthesis of mouse lymphocytes was made by culturing the cells under identical conditions in the presence of HEPES buffer in a humid-air atmosphere. The degree of PHA-induced DNA synthesis was found to vary, depending upon the type of ribonucleic acid or DNA virus treatment. Myxovirus, paramyxoviruses, Mengo virus, leukemic viruses, herpesvirus, and vaccinia virus caused a depression in responsiveness, whereas lactic dehydrogenase virus, adenovirus, and polyoma virus induced an increase in DNA synthesis. Inhibition of DNA synthesis was significant only if the virus was added at 0 h or within the first 12 h after PHA stimulation. Time studies indicated that leukemic and nonleukemic viruses caused similar patterns in the alteration of PHA-induced DNA synthesis.