Bruce Twitchin

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In this study, we investigated seed and auxin regulation of gibberellin (GA) biosynthesis in pea (Pisum sativum L.) pericarp tissue in situ, specifically the conversion of [14C]GA19 to [14C]GA20. [14C]GA19 metabolism was monitored in pericarp with seeds, deseeded pericarp, and deseeded pericarp treated with 4-chloroindole-3-acetic acid (4-CI-IAA). Pericarp(More)
The induction of flowering by one long day (LD) in the grass Lolium temulentum is most closely mimicked by application of the gibberellins (GAs) GA(5) or GA(6), both of which occur naturally. These gibberellins promote floral development but have little effect on stem elongation. Endogenous GA(5) and GA(6) contents in the shoot apex double on the day after(More)
Gabaculine, a conformationally restricted analogue of GABA, is (i) a moderately potent inhibitor (IC(50) 69 muM) of the sodium-dependent uptake of GABA in rat brain slices, (ii) ineffective at 100 muM as an inhibitor of the sodium-independent binding of GABA to membranes from rat brain, (iii) a relatively weak inhibitor (IC(50) > 1 mM) of glutamate(More)
S(+)-2,4-Diaminobutyric acid is at least 20 times more potent than the R(-) stereoisomer as an inhibitor of the sodium-dependent uptake of 4-aminobutyric acid (GABA) in rat brain slices. Both isomers, however, are equipotent as inhibitors of sodium-independent binding of GABA to membranes from rat brain. The latter finding may be relevant to the reported(More)