Figure 1.

Glycine de- or increases THN speed depending on embryo age. (a) Adding 10 mM glycine to embryos produces a THN speed increase in 24 hpf embryos (bottom panel), while in 30 hpf embryos induces a speed decrease. Images for control and > 28 hpf embryos are taken from [3]. Boxes on the transmitted light images on the left indicate the region magnified in the stills from the fluorescent films. Colored dots indicate the position of example cells, also represented by arrows on the right hand side pointing out the start and end positions of the same examples. Scale bars: 25 µm. Elapsed time is given at the top. See also Video 1. (b) THNs were tracked in SIMI°BioCell and tracks corrected for tissue shifts using markers represented by cyan-colored bowls. THNs are shown in orange, and one example marked in blue. See also Video 2. (c) Excess glycine in young embryos increases THN speeds in the central region of the MHB, comparable to the region where excess glycine slows THNs in older embryos. Tracks were classed by their starting point in 10% bins along the MHB, where 0% is the dorsal, 100% the ventral end of the MHB. Values for control and glycine > 28 hpf are taken from [3]. (d) Statistic analysis confirms the notion that glycine affects THNs most strongly in the ventral part of the MHB, using 0–25% for dorsally, and 32.5%-100% for ventrally localized cells as cutoff. Error bars represent SEM. Values for control and glycine > 28 hpf are taken from [3]. (E) WISH analysis against nkcc1 (slc12a2) demonstrates that the gene is widely expressed in the head and brain of the embryo at 30 hpf.