Alterations in Activity of Phosphatases during the Peridinium Bloom in Lake Kinneret

Abstract

Acid and alkaline phosphatases have been isolated from Peridinium cinctum f. westii (Dinophyceae) during an algal bloom in Lake Kinneret. Acid phosphatase activity was fairly constant over the entire period of the bloom, although fluctuations in activity appeared to correlate with the chlorophyll content of the cells. Histochemical studies showed that the enzyme was localized inside the cell. Alkaline phosphatase activity was very low until May, a month after the peak of the bloom, when it increased sharply. Polyacrylamide gel electrophoresis revealed one or two bands of alkaline phosphatase that increased in intensity as the bloom progressed. However, the highest activity of the enzyme (in the last sample collected) corresponded to a new, very intense band on the gels. Similarly to acid phosphatase, alkaline phosphatase was also localized inside the cell. The appearance of alkaline phosphatase is probably related to the available phosphate concentration in the lake, although the influence of other factors that may contribute to the induction of the enzyme cannot be ruled out.

Detection and quantification of alkaline phosphatase in single cells of phosphorus-starved marine phytoplankton

“…This generally agrees with other workers who have noted localization of the enzyme in the outer surfaces of the cell (Kuenzler 1965), at the cell wall (Brandes & Elston 1956), at the plasma membrane (Patni et al 1974) or in the penplasmic region (Matagne et al 1976). This surface localization of AP has been observed in many different groups of phytoplankton as well, including the marine diatoms Chaeotoceros affinis, Skeletonerna costatum and Phaeodactylum tricornutum (Kuenzler & Perras 1965, Moller et al 1975 (Uchida 1992) or the chlorophvte Scenedesmus qnadncanda (Overbeck 1962), t h~s enzyme is apparently not locahzed in the outer membrane When the ELF stalning pattern ivas occasionally observed in Alexandrium fundyense (Ftg 3B), AP was not near the outer membrane but rather showed a more general distribution withln the cell This again suggests that the AP observed in A fundyense may not have been induced by P starvation Expenments with the dinoflagellate Pendinium cinctum, which also has a cellulose wall or theca, showed that AP was localized wlthin the cellular interior (Messer & BenShaul 1969, Wynne 1977 However, when the cell needed the enzyme, ~t was transported to the cell wall and secreted through ~t s pores If A fundyense was producing AP in response to P starvation, then we would expect to observe more ELF-stained cells In the population and the localization should have been peripheral Perhaps our observat~ons of a few labeled cells are more related to enzymatic breakdown of dead or dying Alexandnum cells than to P starvation Schmitter & Jurkiewicz (1981) found that both Gonyaulax polyedra and Gonyaulax tamarensis (= A tamarense) cells contained acid phosphatases and suggested that they play a role In autophagous processes ELF may thus have detected phosphatases that are unrelated to phosphorus nutrition In A fundyense…”

“…Many investigators believe that P is the primary limiting nutrient in freshwater ecosystems For many years, the role of phosphorus (P) as a limit- (Berman 1970, Wynne 1977, Healy & Hendzel 1980, ing nutrient for phytoplankton has been a source of but for marine ecosystems nltrogen (N) is usually thought to be the nutrient in lowest supply (Thomas 1970, Goldm.an et al 1979. Despite this paradigm, some investigators have argued that P is the limiting nutrient for phytoplankton growth in marine systems such as the central gyre of the North Pacific (Perry 1976) or in estuaries along the northeastern margin of the Gulf of Mexico (Smith 1984).…”

Detection of extracellular phosphatases in natural spring phytoplankton of a shallow eutrophic lake (Donghu, China)

“…This could support our observation that the percentage of ELFA-labelled Peridiniopsis cells decreased as the population declined and SRP increased. Similar spring dinoflagellate blooms occurred annually in the warm monomictic Lake Kinneret, but PA usually increased towards the end of the bloom (Wynne, 1977). The predominance of Peridiniopsis in Lake Donghu was favoured by an unusually cold spring, turbid water, and adequate P supply.…”

Review of nitrogen and phosphorus metabolism in seagrasses

“…The ecological role of PAs, especially alkaline PA, has been linked to phosphorus deprivation in many plants (McLachlan, 1980;Lapointe et al, 1994). In contrast, acid PA activities tend to be associated with metabolic and developmental patterns, and thus tend to be less variable (Wynne, 1977;Jansson et al, 1988). Therefore, it has been suggested that acid PAs are continually expressed and may be involved in internal phosphorus metabolism, whereas alkaline PAs, with greater external function, are more responsive to environmental P conditions (Vincent and Crowder, 1995).…”