FIG. 6.

Chronic exposure to selenium results in a progression of behavioral phenotypes leading to lethality. (A) Populations of adult animals placed continuously on NGM agar plates supplemented with 5mM Na₂SeO₃ were scored at 24-h intervals to determine the percentages of animals with each behavioral phenotype (normal, backing [impaired], paralyzed) and for lethality (dead). The percentages of all phenotypes for each time point (0, 24, 48, 72, and 96 h) equal 100%. Each dataset represents six plates with 20 animals per plate and is presented as the mean percentage of animals with each phenotype ± SD. * p < 0.05, compared with normal at the same time point. **p < 0.001, compared with normal at the same time point. # p < 0.05, compared with 24-h within phenotype. ## p < 0.001, compared with 24-h within phenotype. (B) Individual animals were grown singularly on 5mM Na₂SeO₃ plates for a total of 48 h. The behavioral phenotype of each individual animal was assessed every 6 h. A total of 20 individual animals were observed. N = normal (light gray), B = backing (white), P = paralyzed (dark gray), D = dead (black).