Aquatic Sciences Meeting, Albuquerque 2001

CS03 Bacteria

Date: Wednesday, February 14, 2001, Time: 10:45:00 AM

Location: La Cienega

Espeland, E, M, The University of Alabama, Tuscaloosa, USA, eric.espeland@ua.edu

Francoeur, S, N, The University of Alabama, Tuscaloosa, USA, steve.francoeur@ua.edu

Wetzel, R, G, The University of Alabama, Tuscaloosa, USA, rwetzel@biology.as.ua.edu

BACTERIAL PHOSPHATASE IN BIOFILMS: A COMPARISON OF ENZYME ACTIVITY AND INDIVIDUAL PHOSPHATASE EXPRESSION

Bacterial phosphatase of natural photosynthetic biofilms was examined to elucidate the relationship between community phosphatase activity and individual cell expression under phosphorus starvation. Additionally, several fluorescent dyes and substrates were used to compare different methods of assessing bacterial cell-specific phosphatase activity. Phosphorus starvation resulted in increased production of freely-released phosphatase without significant changes in surface-bound phosphatase activity (p < 0.05). The proportion of bacteria expressing phosphatase increased by 21% over time but was not significantly correlated to total phosphatase activity (Spearman’s, r = -0.167, p = 0.424) or surface-bound activity (Spearman’s, r = -0.003, p=0.988). Live bacterial cells comprised a smaller proportion of the total bacterial cell count relative to phosphatase-expressing cells, which indicated surface-bound phosphatase remained active following cell senescence. The fraction of the bacterial community included in calculations strongly influenced determination of bacterial cell-specific phosphatase activity. Estimates of cell-specific activity for both total and surface-bound phosphatase were maximized using live-bacteria counts compared to estimates calculated using DAPI (total bacterial cells) or ELF (phosphatase-expressing bacterial cells) counts.

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Aquatic Sciences Meeting, Albuquerque 2001

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