Effect Of Atrazine On Physiological Metabolic And Gene Transcription In Microcystis Aer Uginosa

Atrazine is a kind of widely used pesticide, it has steady molecular structure and hardly to be degraded, when it remains in water and soil. Atrazine can impact growth and propagate on aquatic organism. Algae are the foundation of aquatic ecological system as primary producers. Algae are also important indicator organism in water contamination. We selected a common blue-green algae Microcystis aanderuginosa as experimental objects, to study the toxic mechanism of Atrazine, through in the physiological and mRNA abundance levels.The results showed that the growth of M. aeruginosa was inhibited exposure to Atrazine, and the growth inhibitory rate was78.6%after96h of exposure to300μg/L Atrazine. Based on the algal growth, we calculated that the EC50values at48h were approximately200μg/L, and at96h, the EC50values were approximately90μg/L. In the study, several of the measured antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) were significantly induced by after48h or96h of exposure Atr. However, we also observed an increase in the the malondialdehyde(MDA) content, compared with the control, suggesting that there was some oxidative damage, but cell could elevate the antioxidant enzymes activities to alleviate oxidative damage.Atrazine can affect the core physiological metabolism progress in Microcystis aeruginosa. Exposure to Atrazine decreased photosynthetic pigment content, reduced the transcript abundance of psaB and rbcL by real-time PCR, the lowest transcription of these genes were only56.3%and51.4%of the control. Exposure to Atrazine affected the assimilation and metabolism of N and P nutrients, reduced the transcript abundance of N and P transport and metabolic genes. Exposure to Atrazine decreased the MC-LR microcystin content, the lowest content was only85.93%of the control, and also reduced the transcript abundance of mcyA、mcyD、mcyH, the lowest transcription of these genes were only33.6%,29.6%and61.3%of the control.The core physiological metabolism progress in Microcystis aeruginosa exhibit daily rhythmic patterns in the LD cycle. Our results demonstrated that many genes involved in circadian oscillator, photosynthesis, biosynthesis of Microcystin and cell division exhibit rhythmic patterns in the LD cycle. Exposure to Atrazine, the circadian rhythms was disappeared. Our findings show that Atrazine can change the circadian expression patterns of core physiological metabolism progress, and these influences are evident at the level of cellular physiology.