Affiliation:
1. Department of Biochemistry, College of Science, University of Jeddah, Jeddah 21589, Saudi Arabia
2. Department Biological Sciences (Emeritus), Wright State University, Dayton, OH 45435, USA
Abstract
Cyanobacteria harmful algal blooms (cyanoHABs) can have impacts on human health, aquatic ecosystems, and the economy. Nutrient management is an important mitigation and even remediation strategy. In this work, the paralytic shellfish toxin (PST)-producing Aphanizomenon (Aphan.) flos-aquae (Linnaeus) Ralfs ex Bornet & Flahault (now identified as Aphan. sp.) single filament isolate NH-5 was grown in P-depleted media, N-depleted media, and complete BG-11 media. Growth and heterocyst and vegetative cells were monitored using dry weight and cell counts. Ultrasonication was used to separate heterocysts from vegetative cells. HPLC-FLD with post-column derivatization was used to determine the saxitoxin (STX) and neosaxitoxin (NEOSTX) concentration per cell. Aphan. sp. NH-5 biomass was lower in the P-depleted media than in the N-depleted media and the control, though higher heterocyst counts were detected in the N-depleted media. The heterocyst toxin concentration was significantly higher compared to the vegetative cells for the N-depleted media, control, and P-depleted media. However, no significant differences were found among all preparations with regard to the STX-to-NEOSTX ratio. We conclude that N limitation induced higher heterocyst numbers and that N fixation activity is a factor behind the increase in the STX and NEOSTX production of Aphan. sp. NH-5.
Subject
Health, Toxicology and Mutagenesis,Toxicology
Reference46 articles.
1. Harmful Algal Blooms;Blaise;Encyclopedia of Aquatic Ecotoxicology,2013
2. USEPA (United States Environmental Protection Agency) (2022, August 21). Cyanobacterial Harmful Algal Blooms (CyanoHABs) in Water Bodies, Available online: https://www.epa.gov/nutrientpollution/harmful-algal-blooms.
3. Evolution of phosphorus limitation in lakes;Schindler;Science,1977
4. Eutrophication of lakes cannot be controlled by reducing nitrogen input: Results of a 37-year whole-ecosystem experiment;Schindler;Proc. Natl. Acad. Sci. USA,2008
5. Life Cycle of Cyanobacterium Aphanizomenon flos-aquae;Yamamoto;Taiwania,2009