Microcystin production in Microcystis aeruginosa: effect of type of strain, environmental factors, nutrient concentrations, and N:P ratio on mcyA gene expression

An efficient and affordable laboratory method to produce and sustain high concentrations of microcystins by Microcystis aeruginosa

“…The inhibition of these protein phosphatases can cause cytoskeletal degradation and breakdown of hepatocytes, causing blood to pool in the liver that is followed by hemorrhaging and organ failure [14]. Over 250 different microcystin congeners have been identified [15] whose toxicity is affected by the variation in molecular structure [16,17] and congener concentration within cyanobacterial cells is affected by changes in environmental factors including light intensity [[18], [19], [20]], pH [18], temperature [18,20], and nutrient concentrations [16,20,21]. Frequently detected and thoroughly studied among these congeners is microcystin-LR (CAS: 101043-37-2, C 49 H 74 N 10 O 12 ), which is regarded as one of the most toxic forms of microcystins [8].…”

“…The experimental cultures were monitored for 46 d. Five 2000 mL PYREX® Erlenmeyer flasks each received approximately 800 mL of BG-11 medium. Erlenmeyer flasks are traditionally used for culturing M. aeruginosa and were therefore chosen for the method validation [20,30]. Each flask was inoculated with approximately 40 mL of M. aeruginosa CPCC 300 from the stock cultures, the lid was tightly covered with aluminum foil, and maintained under the same environmental conditions as outlined previously for the stock cultures.…”

“…For over 60 years, researchers have attempted to decipher the conditions that enable the production and cessation of microcystins by freshwater cyanobacteria [23]. Numerous reports affirm the production of microcystins by M. aeruginosa is linked to physiological and environmental processes including cell division [25,33], light intensity and photoperiod [[18], [19], [20],34], temperature [18,20], ultraviolet [35], and the availability of nutrients [16,20]. To advance further understanding, the need to optimize conditions for culturing M. aeruginosa to produce and sustain high concentrations of microcystins, while being cost-effective, is an important challenge facing researchers.…”

How can water quality be improved when the urban waste water directive has been fulfilled? A case study of the Lot river (France)

“…Positive P-and N-ICEP values mean that diatoms are Si-limited with regard to phosphorus and nitrogen, promoting the growth of non-siliceous, potentially toxic algae. Positive N-ICEP, i.e., with N replenishment, has been suggested to indicate a risk of toxin production by several algal taxa (Gobler et al 2007), but no clear results have been obtained yet (Pineda-Mendoza et al 2016). The results show that in the Lot river, P-ICEP values were all negative (i.e., silica was in excess relative to phosphorus) averaging − 5.9 kg C km −2 day −1 (from − 8.7 to − 2.8 kg C km −2 day −1 ), while N-ICEP was positive (i.e., nitrogen in excess relative to silica) averaging 3.8 kg C km −2 day −1 (from 1.5 to 9.8 kg C km −2 day −1 ), with higher values for the last 2 years under study (7.1 and 9.8 kg C km −2 day −1 in 2013 and 2014, respectively).…”

Microcystins and Daily Sunlight: Predictors of Chronic Liver Disease and Cirrhosis Mortality

“…Microcystis is the main producer of microcystin [2,[6][7], but other toxic cyanobacterial genera can release the biotoxin [6][7][8][9][10]. Such toxins have shown to contaminate water sources used for agriculture, drinking water, and recreation [11,12].…”