title: Maltose excretion by the symbiotic Chlorella of the heliozoan Acanthocystis turfacea.
abstract: Chlorella sp. strain 3.83, a symbiotic Chlorella isolated from the heliozoan Acanthocystis turfacea, excreted between 8% and 16% of assimilated (14)CO2 as maltose in the light (15000 lx), with a pH optimum around 4.8. This percentage increased when the illuminance was lowered (36% at 1700 lx). Release of [(14)C]maltose continued in darkness and could be inhibited by the uncoupler carbonyl cyanide p-trifluoro-methoxyphenylhydrazone and by diethylstilbestrol. Net efflux of maltose was observed even at a concentration ratio of extracellular/intracellular maltose of 7.8. Exogenous [(14)C]maltose (5 mM) was taken up by the cells with a rate <2% of that of simultaneous maltose release, indicating a practically unidirectional transport. It is concluded that maltose excretion is an active-transport process.
authors.affiliation: Lehrstuhl für Zellbiologie und Pflanzenphysiologie, Universität Regensburg, Universitätsstrasse 31, D-8400, Regensburg, Federal Republic of Germany.
authors.forename: B
authors.initials: B
authors.lastname: Matzke
authors.forename: E
authors.initials: E
authors.lastname: Schwarzmeier
authors.forename: E
authors.initials: E
authors.lastname: Loos