Figure 1.
Experimental design with developmental stages, gamma radiation dose levels, and light microscopy photos showing characteristics of embryos in the different developmental stages.
The figure shows pictures of non-irradiated embryos representative of the developmental stages used in the experiment. Early stage: Morula (M) and 2-cell stage (2C) of different eggs (arrow indicates the division between the two cells). Middle stage: Formation of the ventro-transversal cleft, indicated by an arrow. Late stage: The rotatory movement caused a slight change in the position of the embryo in the egg. The two pictures are from the same egg with the embryo in different positions, indicated by a structural change from picture A to B in the area pointed at by the arrows. Shortly before and after hatching: Before hatching it is possible to see the buccal tube, indicated by an arrow, which is also visible in the new born larvae. Scale bars in all pictures represent 25 µm.
Figure 2.
Proportion of hatched eggs of M. cf. tardigradum eggs exposed to 50, 200 and 500 Gy of gamma radiation, during different developmental stages.
Developmental stages are denoted as Early (E), Middle (M) and Late (L). See main text and Fig. 1 for more details on developmental stages. Each bar is based on three replicate samples, each with 15 eggs, and error bars denote standard error of the mean. Estimated mean values (SD): Control, 1.0 (0); E50, 0.76 (0.10); E200, 0.27 (0.067); E500, 0.022 (0.038); M50, 0.91 (0.15); M200, 0.84 (0.17); M500, 1.0 (0); L50, 0.98 (0.038); L200, 1.0 (0); L500, 1.0 (0).
Figure 3.
Proportion of hatched eggs as a function of time (days) after egg laying for different experimental groups, defined by developmental stage at irradiation and dose of gamma irradiation.
Labels denote developmental stage (E = early, M = middle, L = late) and the dose level (50, 200, 500 Gy). Each line is based on the aggregate total of three replicates, i.e. representing 45 eggs.