Jean Pierre Jouanneau

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The presence of totipotent and non-totipotent cells in embryogenic carrot cell suspension cultures was examined by cloning of cell microclusters. Forty clones were isolated and the distribution of their embryogenic potential was studied. Nonembryogenic, weakly and highly embryogenic cell lines were selected. After one year of subculture a second cloning(More)
A variety of early elicitor-induced membrane responses have been described, and their possible role in the generation of second messengers involved in the cascades of events leading to the activation of defence genes is actively investigated. Treatment of tobacco cells with a crude elicitor preparation from Phytophthora megasperma, purified oligouronides(More)
When auxin was omitted during either the preparation or the culture of tobacco mesophyll protoplasts, as well as during both periods, synthesis of beta-glucanase was spontaneously induced. In contrast, when protoplasts were prepared and cultured in the presence of 16 micromolar 1-naphthaleneacetic acid (optimal concentration for protoplast division), the(More)
Auxin starvation of soybean cell suspensions results in the arrest of cell growth after about 4 days. The addition of 4 μM 2,4-D enables cells to divide again after a lag phase of 1 day. By comparing the patterns of in vivo and in vitro protein synthesis, we have identified two sets of polypeptides whose synthesis is positively or negatively regulated by(More)
The patterns of in vivo protein synthesis in soybean cell suspensions were compared by polyacrylamide gel electrophoresis after the cells had been submitted to different stress conditions : treatment with Phytophthora megasperma (Pmg) cell wall elicitors, 2,4-D starvation and heat shock (HS) temperatures. Changes in protein synthesis patterns induced after(More)
Poly(A)-RNA was purified from Nicotiana tabacum cell suspension cultures grown in the presence of N(6)-benzyladenine (BA). Cells were incubated with concentrations of 0.4 micromolar BA, optimal for cell division (OPT) or 10 micromolar BA, a cytostatic concentration (OVD), or without cytokinin (CTL) as a control. After 55 hours, total RNA was extracted from(More)
Cytokinin-requiring tobacco cells were incubated for 10 h in the presence of a labeled cytokinin. N6-benzyl-[2-3H]Ade, and of [8-14C]Ado. After alkaline hydrolysis of total RNA and fractionation of the resulting nucleotides, 80 per cent of the 3H radioactivity of RNA were recovered as the N6-benzyl-Ado nucleotide, covalently inserted into polynucleotidic(More)