Search PubMed⌕ Search

Biomedical subjects

M Sellami

Publications and source records attributed to M Sellami.

48 records · Page 3Linked to original sources
PubMed1983

Enrichment and characterization of the mRNAs of four aminoacyl-tRNA synthetases from yeast.

We have partially purified the messenger RNAs for yeast arginyl-, aspartyl-, valyl-, alpha and beta subunits of phenylalanyl-tRNA synthetases in order to study their biosynthesis and ultimately, to isolate their genes. Sucrose gradient fractionation of poly U-Sepharose selected mRNAs resulted in a ten fold enrichment of the in vitro translation activity of these mRNAs. The translation products of messenger RNAs for arginyl- and valyl-tRNA synthetases have the same molecular weight as the purified enzymes; translation of aspartyl-tRNA synthetase messenger RNA yielded a 68 kD molecular weight polypeptide (while the purified cristallisable enzyme appears as a 64-66 kD doublet, which, as we showed is a proteolysis product). The translation of the mRNAs for alpha and beta phenylalanyl-tRNA synthetase gave polypeptides having the same molecular weight as those obtained from the purified enzyme, but the major translation products are slightly heavier, indicating that they may be translated as precursors. As estimated from centrifugation experiments mRNAs of arginyl-, aspartyl-, alpha and beta subunits of phenylalanyl-tRNA synthetase were 1700-2000 nucleotides long, indicating that alpha and beta are translated from two different mRNAs.

Amino Acyl-tRNA Synthetases↗
PubMedDate not supplied

Structure génétique des cécidomyies des céréales en Tunisie.

Genetic structure of Hessian flies in Tunisia. The genetic structure of M. destructor and M. hordei was investigated by sampling 21 fields of cereals in 14 localities of central and southern Tunisia. As previously shown, there was no strict association between the cereal species (wheat, barley and oat) and the Mayetiola species. M. destructor males displayed no heterozygosity at the Pgm3 locus, indicating that they were hemizygous as is the PGM locus in North America. In M. hordei, heterozygous males were observed at all loci, but strong heterozygote deficits were found at two loci (Mdh2 et Hk). Since no such deficit was observed in females, the population structure of M. hordei was studied only in females. Although heterozygosity was two fold higher in M. hordei than in M. destructor, the two species were similar for other genetic characteristics, including a low (Fst<0.05) but significant (P<0.05) genetic differentiation, no isolation by distance, and similar rates of gene flow (5.7 <or=Nm <or=9.6). These results are discussed in relation to their consequences in the event of controlling Tunisian Hessian flies using wheat cultivars that are resistant to a M. destructor biotype.

Journal Article↗
PubMedDate not supplied

[Incidence of amplification of the C-erb B2/Her-2/neu gene in human breast cancer].

Activation of cellular proto-oncogenes can be detected in several human cancers. In the current study, alterations of C-erb B2 gene in primary human breast cancers were investigated. It was found to be amplified from 2 to 30 fold in 25% of the tumors. Correlations of gene amplification with several disease parameters was evaluated.

Adult↗
PubMedDate not supplied

[Characterization of nucleolar organizers in carcinomatous mammmary lesions].

An argyrophil stain for nucleolar organizer regions (NORs) has been applied to paraffin sections of 24 malignant and 3 benign breast tumors. It was found that the total number of Ag-NORs in malignant breast lesions (3.66) significantly exceeded those in benign lesions (1.65). Relationship between this index and some clinical parameters was studied. A positive correlation between NORs and histological grading and prognostic was found.

Adult↗