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Glucose Utilization by Euglena gracilis var. bacillaris : Short‐Term Metabolic Studies *
Author(s) -
BOEHLER ROBERT A.,
DANFORTH WILLIAM F.
Publication year - 1968
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1968.tb02102.x
Subject(s) - euglena gracilis , glucose uptake , carbohydrate metabolism , respiration , metabolism , biology , euglena , chemistry , biochemistry , food science , botany , endocrinology , insulin , chloroplast , gene
SYNOPSIS. In tryptone media, optimal growth of nonphotosynthetic Euglena gracilis var. bacillaris on glucose occurred with 1% (w/v) glucose at pH 3.5, and required a previous adaptive period in glucose medium. In short term metabolic experiments, glucose uptake was greatly stimulated by small concentrations of tryptone or succinate; effects of shaking suggested that CO 2 has a similar stimulatory effect. Glucose utilization was highly dependent on glucose concentration, with an apparent threshold at about 2 mM and increasing steeply with glucose concentration above this value. In tracer experiments, about 90% of the glucose carbon consumed was assimilated, and about 10% released as CO 2 . Glucose did not stimulate respiration even during rapid glucose utilization. Tracer studies indicated oxidation of endogenous substrates was depressed by an amount which just compensated for the respiration due to glucose. The conditions which allowed rapid glucose utilization by “resting” E. gracilis var. bacillaris were the same as those known previously to be required for growth on glucose. It was therefore concluded that these factors act directly on the main pathways of glucose metabolism.