Mechanism Analysis Of The High Sensitivityof Microcystis Aeruginosa To Silver-nanoparticles

Recent years,much studies have shown that AgNPs can be toxic to phytoplankton,but the uptake and toxicity mechanisms at the molecular level still remain elusive.This studywas talk about the uptake and toxicity mechanisms of AgNPs in a prokaryotic(Microcystis aeruginosa)and a eukaryotic(Chlorella vulgaris)freshwater alga using a combination of proteomic,gene transcription,genetic transformation and physiological analyses,a tenfold diluted concentration of silver nitrate was used as positive control.Here we show that AgNPs were more toxic to the growth,antioxidant defense,and carbohydrate metabolism of M.aeruginosa than of C.vulgaris.And in the course of follow-up study,when the silver ion chelating agent cysteine were exposed together with AgNPs,M.aeruginosawas still under a strong toxic effect,showed that the source of AgNPs toxicity is not only the the silver ions dissociation from the silver-nanoparticles but also from AgNPs themselves.In the study,a new von Willebrand A(VWA)domain-containing protein in M.aeruginoa that mediate Ag uptake from AgNPs when expressed in E.coliwas discovered.This new Ag transport protein,which is absent in eukaryotic algae,is a potential candidate explaining the higher AgNPs toxicity in M.aeruginosa relative to that in C.vulgaris.The present study provides new insights on differential cellular responses to AgNPs in two freshwater algae.