1 2 3 4 5 6 7 8 9

Lead is a transition metal that is sometimes found in drinking water of chicks and animals. Lead interferes with genes that affect the cell signaling pathways during neural development, such as Pax transcription factors and FGF-8, a paracrine factor. These factors are critically important in establishing the boundaries of the fore-, mid-, and hind- brain (Gilbert, 2000). Anwer et al. (Anwer, 1988) experimented with the effects of lead and zinc on developing chick embryos. They injected the yolk sac of 7-day-old chicks with 50ug of lead acetate dissolved in water. The embryos were removed from the eggshell on the twenty-first day of incubation. They found the chicks to be deformed in beak, legs, and body. They also found incidents of hydrocephalus, microphthalmia, and anophthalmia.
Joanna Burger (Burger, 1995) performed a risk assessment for behavioral and physical effects of lead on adult birds. Burger cited research by De Franciscis and Boccalatter, who concluded that there is a relationship between lead exposure and body weight of embryos. They demonstrated that increasing levels of lead caused a decrease in the body weight of chick embryos. Lead exposed chick embryos showed meningocele, cranioschisis, and hydrocephalus. Burger also found many deformities in birds, including one that may be particularly pertinent to our experiment. She found a significant difference in brain weight of barn swallows exposed to lead opposed to those not exposed to lead.

© Cebra-Thomas, 2001

Last Modified: 31 May 2001

[Lab Protocols | Students | Cebra-Thomas | Course | Links ]