Characterization of lysozyme messenger and lysozyme synthesized in vitro.
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Carbon Isotopes↗
Biomedical subjects
B Ricard
Publications and source records attributed to B Ricard.
Rice embryos can express heat-shock genes under anoxia.
Heat-shock proteins (hsps) are induced by a number of oxidative stresses. The proposal that the reduction products of oxygen initiate hsp induction was tested in rice embryos, capable of coleoptile growth under oxygen-free conditions. In such embryos, hsps could be detected by both in vivo labeling and in vitro translation of RNA using the reticulocyte lysate system. It is therefore improbable that the mechanism for hsp induction involves oxygen.
Anaerobiosis↗
Guanine-plus-cytosine content, hybridization percentages, and EcoRI restriction enzyme profiles of spiroplasmal DNA.
The guanine-plus-cytosine (G + C) content of spiroplasmal DNA was calculated from the melting temperature determined spectrophotometrically and the buoyant density determined by equilibrium density gradient centrifugation in CsCl. Only two ranges of G + C values were found: 25-27 mol% and 29-32 mol%. The DNA of the following spiroplasmas has 25-27 mol% G + C: Spiroplasma citri (serogroup I-1); the spiroplasmas pathogenic to the honeybee (KC3, BC3, and B63; serogroup I-2); the corn stunt strain (E275; serogroup I-3); the tick strain 277F (serogroup I-4); the drosophila strain (serogroup II); and one group of flower spiroplasmas (serogroup III). The DNA of a second group of flower spiroplasmas (serogroup IV) and the SMCA strain (serogroup V) has a G + C content of 29-31 mol/. The classification of flower spiroplasmas into two groups on the basis of G + C content agrees well with the groupings based on serologic and protein analysis. Spiroplasmas isolated from honeybees in Morocco (B13) or froghoppers in Corsica (L89) have 29-31 mol% G + C, a value that corroborates the relatedness of these strains and the flower spiroplasmas of serogroup IV found by serologic analysis. Reannealing experiments between the vivo-labeled DNA of S. citri and unlabeled DNA of other spiroplasmas gave the following percentages of hybridization: 64% with honeybee spiroplasma DNA, 49% with corn stunt spiroplasma DNA, and 19% with tick spiroplasma 277F DNA; no significant hybridization was observed with DNA of any other spiroplasma. The taxonomic position of the tick spiroplasma 277F within serogroup I was confirmed by hybridization experiments involving [3H]DNA of this strain. The value of polyacrylamide gel analysis of DNA fragments produced by the action of EcoRI restriction enzyme on DNAs from various spiroplasmas is also discussed.
Animals↗