Studies About Biological Activities Of Aphanizomenon Flos-aquae DC-1 Aphantoxins

Blooms dominated by Aphanizomenon flos-aquae have caused much attention for the secretion of neurotoxic aphantoxins.This study investigated the biological and pharmaceutical activities of aphantoxins using mice and zebrafish as experimental animals.1.The analgesic activities of aphantoxins were tested with two classical models of mice,namely the acetic acid writhing test and hot plate test.The results demonstrated that aphantoxins were able to inhibit the rate of mice wrest induced by acetic acid to 67.84% and increase the pain threshold induced by heat to 72.48%,which indicated good analgesic effects of aphantoxins.2.The influences of aphantoxins on the neural signal system in zebrafish brain were studied through testing the changes in contents of neurotransmitters,activities of their synthetic and catabolic enzymes and transcriptions of the genes encoded the enzymes in zebrafish brain during 24 h after they were injected with the toxins.The results demonstrated declines in the contents of acetylcholine and activities of choline acetyltransferase,and down-regulations in the transcriptions of chat and ache,indicating an inhibited cholinergic signal system.The increases in norepinephrine and epinephrine levels,the reduction in monoamine oxidase activities and the down-regulation of mao transcription demonstrated an enhanced adrenergic signal system.The increases in dopamine levels and tyrosine hydroxylase activities,and the up-regulation of th transcription also demonstrated an enhanced dopaminergic signal system.Aphantoxins were able to have an influence on neural signal system via affecting the synthesis and catabolism of neurotransmitters.3.The influences of aphantoxins on the neurological and hormonal regulation in zebrafish ovary were studied through testing the changes in contents of reproductive hormones,activities of steroidogenic enzymes,contents of neurotransmitters,activities of their catabolic enzymes in zebrafish ovary and transcriptions of genes encoded gonadotrophins in zebrafish brain and genes encoded steroidogenic enzymes in zebrafish ovary during 24 h after they were injected with the toxins.The results demonstrated that the levels of follicle-stimulating hormone and luteinizing hormone were reduced in zebrafish ovary and the transcriptions of fshb and lhb weredown-regulated in zebrafish brain,which indicated an inhibited gonadotrophins control.The reduced activities of steroidogenic enzymes and down-regulated transcriptions of cyp11a1,hsd3 b,cyp17a1,cyp19 a,hsd17b1 in zebrafish ovary indicated an inhibition in the synthesis of sex hormones.The reduced contents of estrogen and progesterone demonstrated an inhibited reproductive function.In addition,the increase in dopamine contents,the decreases in acetylcholine,serotonin and norepinephrine contents,the increase in acetylcholinesterase activities and the decresae in monoamine oxidase activities in zebrafish ovary also indicated a disruption in the sex differentiatin,gametogenesis and ovulation.Aphantoxins were able to have an influence on reproductive function through affecting the neuroendocrine system and neural signal system of gonad.4.The influences of aphantoxins on the biotransformation system in zebrafish liver were studied through testing the changes in activities of biotransformation enzymes and transcriptions of the associated genes in zebrafish liver during 24 h after they were injected with the toxins.The results demonstrated increases in the activities of 7-ethoxyresorufin-O-deethylase,aminopyrine N-demethylase and erythromycin N-demethylase and up-regulations in the transcriptions of cyp1 a and cyp3a65,indicating an induced phase ? oxidation reaction.The declines in epoxide hydrolase,UDP-glucuronosyltransferase,glutathione S-transferase and glutathione reductase activities and the down-regulations of ephx1,ugt1a1,gstp1,gsr transcriptions demonstrated an accumulation of intermediate products produced by the oxidation above and an inhibited phase ? removal of the toxins.Aphantoxins were able to have an influence on the metabolism and detoxification of liver by affecting the activities of biotransformation enzymes.