Recovery of the germfree status of rats and mice monocontaminated with Aspergillus species.

The decontamination of monocontaminated rats and mice is reported in this paper. The monocontaminant micro-organism was an Aspergillus species, and the decontamination was applied with success using nystatin and phenol solutions for animals and materials respectively.

Purification and characterization of a beta-galactosidase from Fusarium oxysporum var. lini.

Beta-D-Galactosidase was purified from a cellular extract of Fusarium oxysporum var. lini by heat shock and successive chromatography on DEAE-cellulose DE-52 and Sephadex G-100. The purified enzyme was homogeneous on SDS gel electrophoresis.

[Cancers, oncogenesis and oncogenes].

The carcinogenic transformation depends on the presence of particular genes, the oncogenes, which are, as a matter of fact, normal cellular genes. The oncogenic retro-viruses are mosaic genomes, transducing oncogenes in the infected cells. These genes are expressed: the product has an activity of protein kinase.

[Cellular differentiation and malignant transformation (author's transl)].

The mechanisms and determination of differentiation of normal and cancer cells were compared by distinguishing them from the phenomena of regulation, retrodifferentiation and maturation. Reference is made to the laws of order in time and space which are superimposed on the common genetic code during the various types of differentiation. In conclusion, the particular mechanisms of malignant differentiation are discussed by taking melanoma and tumor formation by papova-viruses as examples.

Toxicity of radiolytic products from 60 Co-treated starch on microorganisms.

The radiolytic products of a 60Co-irradiated starch are sensitive to the action of catalase, peroxidase and ferrous ions: extracts of irradiated starch so treated loss their toxicity for Escherichia coli. After eliminating the reductones, the toxic activity is attributed to the peroxides and more especially to hydrogen peroxide. Artificial reconstitution of an irradiated starch extract confirms this conclusion and reveals a secondary toxic action of formaldehyde.

[Polyuridylic sequences and negative strands of Sindbis virus-specific RNAs: study by affinity chromatography on poly (A)-sepharose columns (author's transl)].

The experimental conditions of affinity chromatography on poly (A)-Sepharose columns have been determined. This method makes obvious the existence of polyuridylic acid sequences on the negative strands of Sinbis virus-spedific RNAs. The isolated RNAs are negative and positive strands hybrids.

[The length of polyadenylic acid tracts of Sindbis virus RNA: the possible existence of two synthetic mechanisms].

The poly (A) tracts of RNA's from viral particles and from replicative complex belong to two classes of 180 and of 60 nucleotides in length. Those of the mRNA are homogenous and around 280 nucleotides in length. The results presented here strongly suggest the possibility of a copying mechanism in the first case and of a posttranscriptional addition in the latter.