Long-term tracking robust removal of Microcystis-dominated bloom and microcystin-pollution risk by luteolin continuous-release microsphere at different nitrogen levels-Mechanisms from proteomics and gene expression.

Luteolin continuous-release microsphere (CRM) has promising algicidal effect against Microcystis, but how nitrogen (N) level impacted CRM effects on Microcystis growth and microcystins (MCs) pollution was never tracked along long term. This study revealed that luteolin CRM exerted long-term and robust inhibitory effects on Microcystis growth and MC-pollution by sharply decreasing extracellular and total MCs content at each N level, with growth inhibition ratio of 88.18%-96.03%, 92.91%-97.17% and 91.36%-95.55% at 0.5, 5 and 50 mg/L N, respectively, during day 8-30. Further analyses revealed that CRM-stress inhibited transferase, GTPase and ATPase activities, ATP binding, metal ion binding, fatty acid biosynthesis, transmembrane transport and disrupted redox homeostasis to pose equally robust algicidal effect at each N level. At lower N level, CRM-stress tended to induce cellular metabolic mode towards stronger energy supply/acquisition but weaker energy production/consumption, while triggered a shift towards stronger energy production/storage but weaker energy acquisition/consumption as N level elevated, thus disturbing metabolic balance and strongly inhibiting Microcystis growth at each N level. Long-term robust algicidal effect of CRM against other common cyanobacteria besides Microcystis was evident in natural water. This study shed novel insights into inhibitory effects and mechanisms of luteolin CRM on Microcystis growth and MC-pollution in different N-level waters.

Effects of maximum residue limit of triflumezopyrim exposure on fitness of the red imported fire ant Solenopsis invicta.

The impact of exposure to free feeding concentrations of triflumezopyrim to the red imported fire ant, Solenopsis invicta, in maximum residue tolerances for 56 days was investigated to understand whether triflumezopyrim, a novel neonicotinoid, poses unacceptable risks to the environment. Our results demonstrated that neither 0.5 µg/ml nor 0.2 µg/ml triflumezopyrim have a significant impact on the growth of the S. invicta colony and their food consumption (sugar water and locusts) during the length of treatment. While both 0.5 µg/ml and 0.2 µg/ml triflumezopyrim improved the grasping ability of S. invicta, and 0.5 µg/ml not 0.2 µg/ml triflumezopyrim increased their rate of locomotion. In addition, although 0.5 µg/ml and 0.2 µg/ml triflumezopyrim increased their individual aggressiveness index, the probability of the survival of S. invicta was not impacted by triflumezopyrim treatments in aggressive group encounters. This study suggests that triflumezopyrim did not have a negative impact on the fitness of S. invicta at 0.5 µg/ml and 0.2 µg/ml exposures.