Inhibition of tumor cell proliferation by a novel growth regulator from placenta: modulation of membrane phosphorylation and oncogene expression.

The tumor specific inhibition of thymidine uptake by a negative growth regulator isolated from the maternal part of the bovine placenta is in concert with an inhibited expression of ras oncogenes. The results indicate that primary processing is blocked in case of Ha-ras, while a lower transcription rate or a stimulated degradation of mRNA is more likely for N-ras. These reactions are preceded by a specific binding of the inhibitor to tumor cell surface membranes.

Expression of myc and ras oncogenes in two newly established neuroblastoma cell lines.

Two new neuroblastoma cell lines, KG-MH and KM-YH have been established from fresh tumour samples. In vitro growth characteristics are presented together with a karyological analysis. Northern and Southern blot experiments have been performed using molecularly cloned probes for c-myc, N-myc, c-Ha-ras, c-Ki-ras, and N-ras oncogenes.

Aminoacylase-1 isoenzymes: a comparative study.

Analysis of aminoacylase-1 (ACY-1) zymograms from 21 species indicated one structural locus coding for one dimeric enzyme. Among the various strains of five laboratory mammals (Mesocricetus auratus, Cricetulus griseus, Mus musculus, Rattus norvegicus, Cavia porcellus) only in Mus musculus-strains genetic variability was found. Crosses segregating for ACY-1b/ACY-1c reveal a three-banded banding pattern typical for the heterozygous state of a dimeric enzyme.

Molecular cloning and characterization of the MET6 gene of Saccharomyces cerevisiae.

A yeast DNA fragment complementing the met6 mutation in yeast (Saccharomyces cerevisiae) was cloned in a shuttle vector, Yep13, by transforming a yeast host with plasmid DNA prepared from yeast gene bank CV13 of K. Nasmyth. A restriction map of a 6-kb Sau3A insert was constructed.

Electrophoretic comparison of Syrian and Chinese hamster species.

Twenty-six genetic loci were tested in Syrian and Chinese hamster species to investigate the genetic constitution of each species. Electrophoretic variability is reported and implications for genetic drift and phylogenetic relationship are discussed.

Fragment comparison of hamster mitochondrial DNA: general conclusions about the evolution of mitochondrial DNA.

Mitochondrial DNA from heart, liver and kidney of two hamster species, Mesocricetus auratus and Cricetulus griseus has been digested with the restriction endonucleases Bam HI, Bgl I, Eco RI, Hae III, Hind III, Hpa II and Xba I. Cleavage patterns for Hpa II are identical for both species, while only two of seven bands are common with Hae III. All other endonucleases give a species-specific cleavage pattern.