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IMPROVED PROCEDURES FOR THE CLONING AND PURIFICATION OF MICROCYSTIS CULTURES (CYANOPHYTA) 1
Author(s) -
Parker Dorothy L.
Publication year - 1982
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 - 10.1111/j.1529-8817.1982.tb03212.x
Subject(s) - microcystis , axenic , biology , divalent , cyanobacteria , ionic strength , botany , bacteria , nuclear chemistry , biochemistry , chromatography , chemistry , organic chemistry , genetics , aqueous solution
A cloned axenic culture of Microcystis Kützing was obtained by combining two procedures: a) the disaggregation of multicellular Microcystis colonies by dilution into deionized water, and b) the selective growth of Microcystis in agar media containing Na 2 S, which inhibited or killed the associated contaminants. Microcystis growth was stimulated by 0.3–1 mM Na 2 SO 3 , but not by 0.1–33 mM Na 2 SO 4 . Although Microcystis cells survived temporary exposure to high Na 2 S concentrations, their growth was not stimulated by 1 × 10 −5 to 1.0 M Na 2 S. Possible metabolic roles of reduced sulfur compounds are considered. Microcystis colonies disaggregated to unicells at ionic concentrations below 1 mM for univalent cations, 10–100 μM for the divalent cations, and 3–10 μM for Fe 3+ . Higher cation concentrations prompted cell aggregation. With > 100 mM Fe 3+ , the Microcystis capsule appeared rust‐colored. Neither nonionic solutes nor anions detectably influenced aggregation. These observations suggest cation interactions with the Microcystis capsule and are discussed with regard to: a) possible siderochrome activity, cation chelation or luxury uptake of cations, b) the questionability of using cell aggregation as a criterion for identifying Microcystis in samples of unknown ionic strength, c) the utility of low ionic strength media in releasing contaminating bacteria from the capsule and in obtaining algal unicells for cloning, and d) a model for cation interactions with the capsule.