Dissolved organic phosphorus utilization and alkaline phosphatase activity of the dinoflagellate Gymnodinium impudicum isolated from the South Sea of Korea

Abstract

This study investigated alkaline phosphatase (APase) activity and dissolved organic and inorganic phosphorus utilization by the harmful dinoflagellate Gymnodinium impudicum (Fraga et Bravo) Hansen et Moestrup isolated from the South Sea of Korea. Under conditions of limited phosphorus, observation of growth kinetics in batch culture yielded a maximum growth rate (µ max ) of 0.41 /day and a half saturation constant (Ks) of 0.71 µM. In time-course experiments, APase was induced as dissolved inorganic phosphorus (DIP) concentrations fell below 0.83 µM, a threshold near the estimated Ks; APase activity increased with further DIP depletion to a maximum of 0.70 pmol/cell/h in the senescent phase. Thus, Ks may be an important index of the threshold DIP concentration for APase induction. G. impudicum utilizes a wide variety of dissolved organic phosphorus compounds in addition to DIP. These results suggest that DIP limitation in the Southern Sea of Korea may have led to the spread of G. impudicum along with the harmful dinoflagellate Cochlodinium polykrikoides in recent years.

Growth and alkaline phosphatase activity of Chattonella marina and Heterosigma akashiwo in response to phosphorus limitation

“…phosphate (MFP) (Ou et al, 2008), methylumbelliferyl phosphate (MUF-P) (Jauzein et al, 2010), pNPP (Kruskopf and Plessis, 2004), or disodium phenylphosphate (Oh et al, 2010) as substrate. APA varied greatly among microalgal species, such as 10-13.4 fmol/(cell·min) (600-804 fmol/(cell·hr)) for toxic dinoflagellate Alexandrium catenella using MUF-P as substrate (Jauzein et al, 2010), 1-3 fmol/(cell·hr) for Prorocentrum donghaiense, and maximum to 150 fmol/(cell·hr) for Alexandrium catenella, less than 2 fmol/(cell·hr) for the diatom Skeletonema costatum using MFP as substrate (Ou et al, 2008), and 0.02-0.7 pmol/(cell·hr) (20-700 fmol/(cell·hr)) for Gymnodinium impudicum using disodium phenylphosphate as substrate (Oh et al, 2010).…”

“…APA varied greatly among microalgal species, such as 10-13.4 fmol/(cell·min) (600-804 fmol/(cell·hr)) for toxic dinoflagellate Alexandrium catenella using MUF-P as substrate (Jauzein et al, 2010), 1-3 fmol/(cell·hr) for Prorocentrum donghaiense, and maximum to 150 fmol/(cell·hr) for Alexandrium catenella, less than 2 fmol/(cell·hr) for the diatom Skeletonema costatum using MFP as substrate (Ou et al, 2008), and 0.02-0.7 pmol/(cell·hr) (20-700 fmol/(cell·hr)) for Gymnodinium impudicum using disodium phenylphosphate as substrate (Oh et al, 2010). The APA levels of 4.76-46.4 fmol/(cell·hr) for C. marina in this study were far less than those reported for dinoflagellates species A. catenella (Jauzein et al, 2010;Ou et al, 2008) and G. impudicum (Oh et al, 2010), however much high than those reported for P. donghaiense and S. costatum (Ou et al, 2008). APA levels for H. akashiwo were comparable to those of P. donghaiense and S. costatum (Ou et al, 2008).…”

“…APA is inducible by low extracellular DIP concentrations for many marine phytoplankton species (Ivancic et al, 2009;Jauzein et al, 2010;Oh et al, 2010), and increased with decreasing DIP concentrations in both natural sea waters and batch cultures (Duhamel et al, 2010;Dyhrman and Ruttenber, 2006;Hoppe, 2003;Huang et al, 2007;Ou et al, 2010). However the threshold DIP concentrations for AP induction varied greatly among species, e.g., 0.83 μmol/L for G. impudicum (Oh et al, 2010); 0.4-1 μmol/L for A. catenella (Jauzein et al, 2010), 3.3 μmol/L for Gymnodinium catenatum (Oh et al, 2002), 1 μmol/L for the natural phytoplankton community in the southern Baltic Sea (Nausch, 1998), and 0.1 μmol/L in the transition zone of the North-western African upwelling system (Sebastián et al, 2004). Meanwhile the intracellular P pool and the internal N:P ratio have often been reported as the potential controlling factor that may regulate AP synthesis (Hoppe, 2003;Lomas et al, 2004;Vidal et al, 2003).…”

Utilization of dissolved organic phosphorus by different groups of phytoplankton taxa

“…It has been reported that many dinoflagellate species can effectively utilize a variety of both inorganic and organic compounds as phosphorus sources (Matsuda et al, 1999;Oh et al, 2002Oh et al, , 2010Huang et al, 2005;Yamaguchi et al, 2005). However the raphidophytes, such as Chattonella ovata, F. japonica, and H. akashiwo, have been shown not growing on phosphomonoesters other than nucleotides (Yamaguchi et al, 2005(Yamaguchi et al, , 2008.…”

“…A trend of increasing N:P ratios has been reported for Chesapeake Bay (Fisher et al, 1992), the northern Red Sea (Li et al, 1998), the South Sea of Korea (Oh et al, 2010), and the Seto Inland Sea (Oh et al, 2005). Chinese coastal waters have also been experiencing P limitation over the last two decades (Huang et al, 2007;Wang et al, 2008;Dong et al, 2010), and the average N:P ratio is high.…”