Transport and metabolism of glycolic acid by Chlamydomonas reinhardtii

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:7160803

Wilson, B J

In order to understand the excretion of glycolate from Chlamydomonas reinhardtii, the conditions affecting glycolate synthesis and metabolism were investigated. Although glycolate is synthesized only in the light, the metabolism occurs in the light and dark with greater metabolism in the light due to refixation of photorespiratory CO/sub 2/. The amount of internal glycolate will affect the metabolism of externally added glycolate. When glycolate synthesis exceeds the metabolic capacity, glycolate is excreted from the cell. The transport of glycolate into the cells occurs very rapidly. Equilibrium is achieved at 4/sup 0/C within the time cells are pelleted by the silicone oil centrifugation technique through a layer of (/sup 14/C) glycolate. Glycolate uptake does not show the same time, temperature and pH dependencies as diffusion of benzoate. Uptake can be inhibited by treatment of cells with N-ethylmaleimide and stimulated in the presence of valino-mycin/KCl. Acetate and lactate are taken up as quickly as glycolate. The hypothesis was made that glycolate is transported by a protein carrier that transports monocarboxylic acids. The equilibrium concentration of glycolate is dependent on the cell density, implying that there may be a large number of transporter sites and that uptake is limited by substrate availability.

• Research Organization: Michigan State Univ., East Lansing (USA)
• OSTI ID: 7160803
• Country of Publication: United States
• Language: English

Related Subjects

550501 -- Metabolism-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALGAE
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CENTRIFUGATION
CHLAMYDOMONAS
ELECTROMAGNETIC RADIATION
GLYCOLIC ACID
HYDROXY ACIDS
IMIDES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MEMBRANE TRANSPORT
METABOLISM
MICROORGANISMS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLANTS
RADIATIONS
SEPARATION PROCESSES
TRACER TECHNIQUES
UNICELLULAR ALGAE
VISIBLE RADIATION