RESUMO
Abstract Presence of the relatively new sulfonylurea herbicide monosulfuron-ester at 0.03-300 nmol/L affected the growth of two non-target nitrogen-fixing cyanobacteria (Anabaena flos-aquae and Anabaena azotica) and substantially inhibited in vitro Acetolactate synthase activity, with IC50 of 3.3 and 101.3 nmol/L for A. flos-aquae and A. azotica, respectively. Presenting in 30-300 nmol/L, it inhibited protein synthesis of the cyanobacteria with less amino acids produced as its concentration increased. Our findings support the view that monosulfuron-ester toxicity in both nitrogen-fixing cyanobacteria is due to its interference with protein metabolism via inhibition of branch-chain amino acid biosynthesis, and particularly Acetolactate synthase activity.
Assuntos
Pirimidinas/toxicidade , Compostos de Sulfonilureia/toxicidade , Anabaena/efeitos dos fármacos , Anabaena/metabolismo , Dolichospermum flosaquae/efeitos dos fármacos , Dolichospermum flosaquae/metabolismo , Ésteres/toxicidade , Herbicidas/toxicidade , Fixação de Nitrogênio/efeitos dos fármacos , Anabaena/genética , Dolichospermum flosaquae/genética , Aminoácidos/metabolismo , Nitrogênio/metabolismoRESUMO
Presence of the relatively new sulfonylurea herbicide monosulfuron-ester at 0.03-300nmol/L affected the growth of two non-target nitrogen-fixing cyanobacteria (Anabaena flos-aquae and Anabaena azotica) and substantially inhibited in vitro Acetolactate synthase activity, with IC50 of 3.3 and 101.3nmol/L for A. flos-aquae and A. azotica, respectively. Presenting in 30-300nmol/L, it inhibited protein synthesis of the cyanobacteria with less amino acids produced as its concentration increased. Our findings support the view that monosulfuron-ester toxicity in both nitrogen-fixing cyanobacteria is due to its interference with protein metabolism via inhibition of branch-chain amino acid biosynthesis, and particularly Acetolactate synthase activity.
