Search

With the use of a BaCl2solution containing radioactive Ba2+ions, kinetics of cation exchange have been done on a Kenya vermiculite, natural on one hand and previously oxidized either by 50°C water or oxygenated water on the other hand. Correlatively, the quantity of ferric iron in the layer has been determined by E.P.R. These two methods have shown that during an oxidation the proportion of iron which stays in the octahedral layer depends upon the nature of the oxidizing agent. During a weak oxidation, the iron stays entirely in an octahedral layer and the exchange capacity of the vermiculite decreases; on the other hand, during an oxidation by oxygenated water, part of the iron is extracted from the octahedral layer and the exchange capacity of the vermiculite is not changed, as established by the studies of Farmer (Farmer et al., 1971). Kinetic data for Llano vermiculite also are reported and compared with those for the Kenya vermiculite.

Simian virus 40-transformed nonpermissive cells in which neither infectious viral DNA nor virions had previously been detected reproducibly yield low levels of infectious simian virus-40 DNA after treatment with extracts of normal permissive cells. Virions were obtained in one out of 37 experiments. Activation of the viral genome is detected only with normal permissive cell extracts and only in simian virus 40-transformed cell lines that are rescuable by heterokaryon formation or by treatment with chemicals. The activating factor(s) is insensitive to deoxyribonuclease and ribonuclease, but is sensitive to heat at 56° and to proteolytic enzymes.

Four clones of a somatic monkey-mouse hybrid cell line were studied. One of these clones produced both mouse and monkey interferon, while the three others produced only mouse interferon. All four were, however, sensitive to both mouse and monkey (or human) interferon. The karyotype analysis of these four hybrid clones and the parental cell lines enabled us to locate the possible genetic site governing the synthesis of monkey interferon on a small subtelocentric monkey chromosome. The genetic site responsible for the synthesis of the antiviral protein is located on a different (monkey or mouse) chromosome.