Formation of large colonies: a defense mechanism of Microcystis aeruginosa under continuous grazing pressure by flagellate Ochromonas sp.

By Zhen Yang, Fanxiang Kong. 2012

87 citations recorded by the source corpus.

Induced colony formation under grazing pressure has been reported in our previous results. However, the colonies induced in these studies comprised only tens of cells which are far smaller than the naturally occurring colonies. In this work, unicellular Microcystis aeruginosa Kutzing were co-cultivated with flagellate Ochromonas sp. for 50 d to investigate colony formation in M. aeruginosa under continuous grazing pressure. Results revealed that colonial M. aeruginosa formed on the 10th d under the grazing pressure of flagellate. These algal colonies resulted from the daughter cells of freshly dividing cells that failed to separate during the reproductive process. The diameters and cell numbers of the colonies increased slowly with time. Under continuous grazing pressure by Ochromonas sp. for 50 d, the diameter of some colonies reached over 180 μm. Analysis showed that the extracellular polysaccharide (EPS) content and relative gas vesicle (RGV) of each cell increased significantly after colony formation. However, there was no significant difference on the monosaccharide composition between unicellular and colonial M. aeruginosa. The loose aggregation of cells in the floating colonies suggests that a correlation probably exists between cell compactness and colony buoyancy.

Subfields: Ecology, Evolution, Behavior and Systematics, Environmental Chemistry, Oceanography

View Paper: https://www.semanticscholar.org/paper/c845487acb0ec4aab2471ffe288194e0797f8fed

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In Ecology, Evolution, Behavior and Systematics

1. M. Esterhuizen-Londt
2. S. Pflugmacher
3. A. Omidi

In Environmental Chemistry

1. M. Esterhuizen-Londt
2. S. Pflugmacher
3. A. Omidi

In Oceanography

1. M. Esterhuizen-Londt
2. S. Pflugmacher
3. A. Omidi

Citations in the corpus

• Still challenging: the ecological function of the cyanobacterial toxin microcystin – What we know so far (2018, background): “Continuous predator pressure by Ochromonas sp. as well as culturing with the filtered cultures of the flagellate fed with M. aeruginosa induced colony formation in unicellular M. aeruginosa PCC 7806 (Yang & Kong, 2012; Yang et al., 2009).”