Participation of an active transport system in berberine-secreting cultured cells of Thalictrum minus

Abstract

The release of the benzylisoquinoline alkaloid berberine from cultured cells of Thalictrum minus into the medium proved to be temperature-dependent and was suppressed by such inhibitors of the plasma membrane-bound ATPase as vanadate and diethylstilbestrol. These results indicate that berberine is secreted through an energy-requiring process located in the plasma membrane of berberine-producing T. minus cells. This is the first finding that a secondary metabolite of plant cell culture is secreted by an active transport system.

Characteristics of Scopolamine-releasing Hairy Root Clones ofDuboisia leichhardtii

“…In our previous paper,6) we suggested that high concentrations of NO; may have some effects on the physiological conditions of the root tissue, including the change of a membrane transport system as found in cultured cells of Thalictrum minus. 11) Based on the data obtained here, scopolamine release of DL47-1 would depend on the high H6H activity in HF-3 medium, although not in other clones. It seemed that an excess of scopolamine converted by high H6H activity of DL47-1 in HF-3 medium, overflowed from the alkaloid pool of the root tissue and then was released into the medium.…”

Uptake and accumulation of ajmalicine into isolated vacuoles of cultured cells of Catharanthus roseus (L.) G. Don. and its conversion into serpentine

“…Since we were not able to determine initial uptake kinetics of ajmalicine we cannot exclude the involvement of carriers like those proposed by DeusNeumann and Zenk (1986), Mende and Wink (1987), and Yamamoto et al (1987Yamamoto et al ( , 1989. The highly specific carriers for vindoline and reticuline as described in Deus- Zenk (1984, 1986), could be inhibited by DCCD in the absence of ATP.…”

“…Several authors have presented evidence for energy-requiring alkaloid transport by specific carriers, and in a number of these reports protons appear to be involved in a proton-antiport carrier system. Zenk 1984, 1986;Mende and Wink 1987;Wink and Mende 1987;Yamamoto et al 1987Yamamoto et al , 1989Ehmke et al 1988). A totally different role for protons, however, has also been proposed: the alkaloids form a pH-dependent equilibrium between a neutral (non-protonated) and a charged (protonated) form.…”

Stability of alkaloid production in cell suspension cultures of Tabernaemontana divaricata during long-term subculture

“…Little is known about the excretion mechanism of secondary metabolites. Yamamoto et al [25] demonstrated that cell cultures of Thalictrum minus secrete berberine into the culture medium through an energy requiring process. But berberine is not released into the medium by all cultures of T. minus [26].…”