Figure 2.

Induction of an alkalinization response of a C. roseus plant cell suspension by in vitro synthesized metabolites of zebrafish and carp embryos (see Material and Methods). (A) Typical response curve obtained with metabolites from gastrulation stage zebrafish embryos (arrow, the time point of addition; dotted line, fractions with retention times similar to chitin tetraose; solid line, fractions with retention times similar to chitin pentaose; dashed line, maximal pH shift obtained by adding 0.3 μg of chitin tetraose). (B) Alkalinization response of metabolites synthesized in vitro by embryo extracts at early gastrulation stage, late gastrulation stage, and segmentation stage, indicated as a percentage of the maximal pH shift (%ΔpH_max). Results shown are from experiments independent of those shown in A. This indicates a variation of approximately 20% in the alkalinization assay. Indicated also are the results obtained with extracts of late gastrulation stage embryos that were pre-incubated with DG42 antiserum or preimmune serum.