Physiological, Diurnal and Stress-Related Variability of Cadmium-Metallothionein Gene Expression in Land Snails
Fig 2
Diurnal rhythmicity of CdMT gene expression of control and Cd-exposed Roman snails.
(A) CdMT mRNA copy numbers over a time span of 20 hours, including six sampling time points, in control (Co) and Cd-exposed snails (Cd) (n = 5). Significance of the curves through the diurnal cycle (Two Way ANOVA) was only observed for unexposed control snails (asterisk). No significant differences were found by multiple comparisons within the control and Cd-treated group. (B) Bar graph with means and standard deviation (+SD) of CdMT mRNA copy numbers between control and Cd-exposed individuals (n = 30 each). Different lowercase letters (a, b) indicate significant differences (t-test) (C) Time-dependent CdMT mRNA expression of Cd-exposed snails (P = <0.001) over a time span of 20 hours, shown after exclusion of non-feeders (definition see text) from the dataset (n = 3–5). The peak of CdMT mRNA copy numbers at 08:30 am was compared to all other time points. Significance of multiple comparison is indicated by different lower case letter b. Significance of Two Way ANOVA is indicated by an asterisk. The light period (long white bars) lasted from 07:00 am to 07:00 pm and dark period (long black bars) from 07:00 pm to 07:00 am.