Developmental study of mercury effects on the fruit fly (Drosophila melanogaster)

Abstract

Environmental pollution caused by heavy metals such as mercury is one of the most important human problems. It might have severe teratogenic effects on embryonic development. Some pharmacological and physiological aspects of fruit flies (Drosophila melanogaster) are similar to humans. So the stages of egg to adult fruit fly, as a developmental model, were employed in the study. Wild adult insects were maintained in glass dishes containing standard medium at 25 °C in complete darkness. Five pairs of 3-day old flies were then transferred to standard culture dishes containing different concentrations of mercury ion. They were removed after 8 hours. We considered the following: The rate of larvae becoming pupae and pupae to adults; the time required for the development; the hatching rate in the second generation without mercury in the culture; the morphometric changes during development in both length and width of the eggs through two generations; larvae, pupae and adult thorax length and width. The results showed that mercury in culture (20–100 mg/l) increase the duration of larvae (p<0.01) and pupae (p<0.01) development, the rate of larvae becoming pupae (p<0.001); pupae maturation (p<0.05), the hatching rate (p<0.01), the length (p<0.05) and width of larvae (p<0.01) and pupae (p<0.001) and the length in the adult thorax (p<0.01) decreased significantly. There was no effect upon the size of eggs. There were also no larvae hatching in concentrations of 200 mg/l of mercury. Negative effects of mercury as a heavy metal are possibly due to the interference of this metal in cellular signaling pathways, such as: Notch signaling and protein synthesis during the period of development. Since it bonds chemically with the sulfur hydride groups of proteins, it causes damage to the cell membrane and decreases the amount of RNA. This is the cause of failure of many enzyme mechanisms.

Specific Association of Teratogen and Toxicant Metals in Hair of Newborns with Congenital Birth Defects or Developmentally Premature Birth in a Cohort of Couples with Documented Parental Exposure to Military Attacks: Observational Study at Al Shifa Hospital, Gaza, Palestine

“…Mercury is a teratogen, with no known mutagenic action; it transpasses the placenta [ 37 , 38 , 39 , 40 ], interferes in key pathways in development [ 42 , 43 , 44 ]: Notch pathway [ 42 ], modulation of key enzymatic antioxidant and oxidative stress makers [ 44 , 45 ]; it affects sperm phenotypes [ 46 ], and various organ compartments during rat embryogenesis [ 47 , 48 ], and is neurotoxic [ 17 , 49 ]. Mercury is an endocrine disruptor and affects spermatogenesis, causes malformations and reproductive damages in mammals and human [ 10 , 50 ].…”

Determination of twenty chemical element contents in normal and goitrous thyroid using X-ray fluorescent and neutron activation analysis

“…Negative effects of Hg are due to the interference of this metal in cellular signaling pathways and protein synthesis during the period of development. Since it bonds chemically with the sulfur hydride groups of proteins, it causes damage to the cell membrane and decreases the amount of RNA [120]. Moreover, it was shown that Hg may be involved in four main processes that lead to genotoxicity: generation of free radicals and oxidative stress, action on microtubules, influence on DNA repair mechanisms and direct interaction with DNA molecules [121].…”

Twenty Chemical Element Contents in Normal and Cancerous Thyroid

“…Negative effects of Hg are due to the interference of this metal in cellular signaling pathways and protein synthesis during the period of development. Since it bonds chemically with the sulfur hydride groups of proteins, it causes damage to the cell membrane and decreases the amount of RNA [100]. Moreover, it was shown that Hg may be involved in four main processes that lead to genotoxicity: generation of free radicals and oxidative stress, action on microtubules, influence on DNA repair mechanisms and direct interaction with DNA molecules [101].…”