The inhibitory effect of calcium on Cylindrospermopsis raciborskii (cyanobacteria) metabolism
Carneiro, Ronaldo LealAlípio, Ana Carla NascimentoBisch, Paulo MascarelloAzevedo, Sandra Maria Feliciano de Oliveira ePacheco, Ana Beatriz Furlanetto
Cylindrospermopsis raciborskii (Woloszynska) Seenaya & Subba Raju is a freshwater cyanobacterium of worldwide distribution. In the North-eastern region of Brazil many eutrophic water reservoirs are characterized by the dominance of C. raciborskii, with recurrent occurrence of blooms. These water bodies have high conductivity due to a high ionic concentration, and are defined as hard (with high values of CaCO3). In this study, we investigated the long-term effect (12 days) of high calcium concentration (8 mM Ca2+) on C. raciborskii (T3 strain) growth, morphology, toxin content, and metabolism. Changes in protein expression profiles were investigated by proteomic analysis using 2D gel electrophoresis and mass spectrometry. A continued exposure to calcium had a pronounced effect on C. raciborskii (T3): it limited growth, decreased thricome length, increased chlorophyll-a content, altered toxin profile (although did not affect PST content, saxitoxin + neosaxitoxin), and inhibited the expression of proteins related to primary metabolism.
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