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Phosphatase Expression by Chlorella Vulgaris (Chlorophyceae) is Mediated by Internal Phosphorus Levels and External pH
Author(s) -
Evens T. J.,
Koenig R.
Publication year - 2002
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.38.s1.20.x
Subject(s) - biology , phosphorus , alkaline phosphatase , phosphate , photobioreactor , phosphatase , chlorophyceae , acid phosphatase , chlorella vulgaris , biochemistry , eutrophication , phosphorus deficiency , botany , enzyme , algae , ecology , chlorophyta , chemistry , nutrient , biomass (ecology) , organic chemistry
Phosphorus has been implicated as one of the causative agents of the eutrophication of lacustrine, estuarine and coastal waters. One of the major inputs of phosphorus into these waters comes from agricultural nonpoint sources in the form of dissolved organic phosphorus (DOP). In order to better understand how DOP may directly impact the microalgal community structure, it is necessary to understand the physiology of DOP uptake and utilization. To this end, cultures of Chlorella vulgaris were grown in custom photobioreactors in acid (pH 5.5) and alkaline (pH 7.5) media under phosphate replete and starved conditions in order to determine the types and triggers of phosphatase expression by this organism. Analysis of differential phosphatase expression during phosphate stress indicates that cultures of C. vulgaris grown under alkaline conditions derepressibly express two alkaline phosphatases, while cultures grown under acid conditions weakly express only one alkaline phosphatase. Analysis of internal and external phosphorus levels, whole‐cell phosphatase activity and in‐gel activity of protein extracts indicate that alkaline phosphatase expression is further mediated by internal, as opposed to external, phosphorus levels.