Title: UPTAKE, METABOLISM, AND RELEASE OF CAMP IN <i>SELENASTRUM CAPRICORNUTUM</i> (CHLOROPHYCEAE)<sup>1</sup>
Abstract: ABSTRACT Uptake rate, intracellular metabolism, and extracellular release of cAMP were examined in batch cultures of the unicellular alga Selenastrum capricornutum Printz (Chlorophyceae). cAMP uptake was linearly dependent on external substrate concentration (0.5 nM to 1 mM) over a broad range of culture cell densities (1.7‐5 × 10 6 cells. mL −1 ) to mid‐to‐late log phase growth. Chromatographic analyses indicated that the majority of assimilated [ 3 H]‐cAMP was converted within 30 min to radiolabelled material which co‐chromatographed with ADP/ATP and adenosine. About 20% of the ( 3 H]‐label originally added to cells as a [ 3 H]‐cAMP was released to the extracellular medium within 10 min, and chromatographic analyses demonstrated that most of the radiolabelled material was released as cAMP. Analyses with cell suspensions preincubated in KCN or DCMU suggested that cAMP release, but not uptake, was repressed by respiratory or photosynthetic electron flow inhibitors. However, the data were consistent with a passive CAMP uptake mechanism only if much of the assimilated CAMP was bound or compartmentalized.
Publication Year: 1989
Publication Date: 1989-06-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 11
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