Studio e controllo di pavimentazioni stradali a bassa emissione sonora in ambito urbano

Rapporto di ricerc

Embryotoxic effect of Deltamethrin on the zebrafish, Danio rerio

INTRODUCTION: The effect of Deltamethrin (from 10-1 to 5.10+9 pg/l), drug utilised in intensive aquaculture[1-2], has been evaluated by determining death rate and alterations of embrionic development, in particular on the nervous system. As a test organism Danio rerio was chosen, being a very useful organism to evaluate embryotoxicity of several different compounds[3-4]. RESULTS: Death rate after 7 days ranged from about 70% up to 100%, respectively from 10-1 to 10+9 pg/l and from 1.25 to 5.10+9 pg/l. By the 1st day from the start of the experiment, animals showed progressively evident motility alterations, up to complete paralyse and death, after the 6th day. Deltametrin also induces reduced pigmentation, cephalic/trunk alterations and lack of yolk sack resorbment. Immuno-hystochemical observations evidenced abnormal neuronal phenotype[5]. CONCLUSIONS: These results can give account of the possible effect on non target species of the therapeutic and prophylactic practices involved in ectoparasite control

Embryotoxicity of flumequine on Danio rerio: mortality, morphological/histological alterations and changes in calmoduline gene expression

Toxic and teratogenic effects of sub-acute exposure to 5 and 50 µg/l Flumequine (9-fluoro-6,7-dihydro-5-methyl-1-oxo-1H, 5H-benzene), an antibiotic used in aquaculture, have been investigated on Danio rerio. This model was chosen being easy to handle and particularly sensitive to chemical and physical stress during reproductive processes. Results showed that 35 days treatment (at both concentrations) cause a significant increase in embryos mortality rate, mainly due to a dramatic toxic effect in the first four days treatment. Furthermore 35 days treatment (at both concentrations) induced developmental alterations in trunk and unpaired fins: in particular, trunk is often thinner on both dorso-ventral and medium lateral axes, and developmental defects in cartilage, muscular and neural structures can be found. Muscular tissue was altered in the tail region: myosepta were irregular or absent; muscle bundles were discontiguous. In treated embryos a significant reduction of signal intensity in both trunk and dorsal branches of metameric spinal nerves was found by in situ hybridisation with a probe for calmoduline messenger RNA. These results account for the possible multiple effects on non target species of antimicrobial drug environmental contamination

thiophanate methyl effects on Danio rerio embyonic development: morphological and molecular alterations

INTRODUCTION: The Thyofanate Methyl is a pesticide and fungicide used in agriculture [1-2]. Our aim was therefore to assess the effects of toxicity and teratogenicity of acute doses of thiophanate methyl on embryonic development of Danio rerio[3]. METHODS: Embryos were exposed to different thyofanate metil concentrations, from 1µg/L to 10mg/L, for 144 hours at 28°C and were observed every 24 h for mortality and sublethal effects. The expression of MyoD, myogenin and myf5 genes was observed by in situ hybridization[4-5]. The 6 days larvae were labeled with anti-acetylated tubulin antibody, colored by diaminobenzidine (DAB) [6]. RESULTS and CONCLUSIONS: Survival and early development of the embryos were not obviously influenced by Thyofanate Methyl concentrations below 10mg/L, but at this concentration the embryos displayed alterations in neural development included weak tactile responses, loss of equilibrium and inability to swim. These treated embryos showed also: 1) an alteration of the spatial distribution of transcripts of MyoD and Myf-5 and myogenin signal was absent. 2) the localization of acetylated tubulin showed the breakage and the disorganization of the lateral line. Therefore, thiophanate-methyl at a concentration of 10 mg /L alters both skeletal muscle differentiaiton that the peripheral nervous system axogenesis. Our studies suggest that the negative effects of T.M. on vertebrate embryogenesis are substantial, therefore the T.M. is a possible contaminant of agriculture areas