Cartographie de restriction comparée de la séquence d''ADN hautement répétée coupée par Bam HI chez Papio papio et P. cynocephalus

Highly repeated DNA sequences from two baboon species (Papio papio and P. cynocephalus) have been compared using restriction endonucleases. The two species share a 343 base pairs tandemly repeated DNA, that is cut once by Bam HI. Papio cynocephalus differs from P. papio by loss of an EcoRI star site in the repeated sequence.     

Composés glucidiques et azotés et résistance à la sécheresse chez Ailanthus altissima

In Ailanthus altissima, carbohydrate and protein reserves are mainly localized in the tap-root. Under drought stress they are very quickly hydrolysed. Despite the water deficiency, an increase in starch synthesis is observed in the leaves and stem during the first stages of stress. Stimulation of the cambial activity of the stems and an increase in protein content have also been observed. Chemical analyses have shown a high proline content which increases markedly following drought stress, especially in the tap-root.     

Dosages protéiques et profils d''activités enzymatiques comparés chez les deux espèces de babouins Papio anubis et P. cynocephalus

Biochemical levels of serum proteins and enzymes were investigated in two populations of the baboons Papio anubis and P. cynocephalus. The mean average levels of proteins or enzyme activity are the same in the two species. The only difference concerns the level of an inhibitor of pseudocholinesterase in a few individuals of Papio anubis.     

Méthylations biologiques chez le crabe Carcinus maenas; inhibition in vitro par une fraction purifiée extraite des glandes androgènes

Extracts from muscles, testis, seminal vesicles and ovaries of the Crab, Carcinus maenas, have been studied in vitro, in presence of [¹⁴C]-methyl S-adenosylmethionine, with an E. coli tRNA as methyl acceptor. The highest level of methylases is found in the testis. It has been reported previously that a purified fraction extracted from the androgenic glands of Carcinus maenas inhibits the vitellogenesis in ovaries. We now show that the same fraction inhibits tRNA methylation in an extract of testis as methylase; a 50 per cent inhibition is obtained with about 10 μg of a purified fraction corresponding to 15 glands. With an enzymatic preparation from the ovaries, a 50 per cent inhibition of the tRNA methylase is observed with the purified extract from 4 glands.