Effect of chlorination and cell growth on toxin production and gene expression in Cylindrospermopsis raciborskii

Abstract

Cylindrospermopsis raciborskii is a filamentous nitrogen fixing cyanobacterium found in many source water in Taiwan and many other countries with the capability of producing cyanotoxin cylindrospermopsin Recent studies for oxidation of cyanobacteria in w atertreatment systems have been only focused on high-dose of oxidants However applications of low-dose oxidants do not quickly lyse cells and their effect on the cells is xepcetd to be dissimilar to that for high-dose oxidation The difference might include change of gene expression and change of production rate of toxins Therefore it is important to study the interaction between cyanobacteria and oxidants under low dose conditions In this study oxidation experiments of C raciborskii were conducted and cell integrity gene expression of mRNA and cyanotoxin concentration during the experiments were measured Viability Polymerase Chain Reaction (vPCR) coupled with PMA dye was used to evaluate cell integrity RNA was extracted and quantified with transcription real-time quantitative polymerase chain reaction (RT-qPCR) for the mRNA of C raciborskii Enzyme-linked immunosorbent analysis (ELISA) was used to measure cylindrospermopsin concentration The results of oxidation experiments showed a 2-2 6 fold upregulation of toxin-producing genes and an increase of toxin concentration after chlorination at 0 1 mg/L indicating the response of cyanobacteria to the oxidative stress from chlorine The results of this study showed that the environmental pressure caused by low-dose oxidants to C raciborskii cannot be ignored

Date of Award	2020
Original language	English
Supervisor	Tsair-Fuh Lin (Supervisor)