FIG. 4.

mRNA abundance in the light organ of aposymbiotic and symbiotic light organs was not significantly different during the onset of the symbiosis. (A) Real time RT-PCR using actin-specific primers and mRNA from light organs of 12-h animals. Three independent mRNA pools (1 to 3) were extracted for each of the two conditions, and triplicate real-time RT-PCRs were conducted for each mRNA pool. For all PCR runs, standards run concurrently had a correlation coefficient of 1.0 ± 0.02 and a slope of −3.3 ± 0.2, indicating that the efficiency of the PCR was ∼2, i.e., each PCR cycle yielded a twofold increase in product. No significant differences were detected between aposymbiotic and symbiotic mRNA within a given extraction trial (Student's t test; P < 0.05). (B) Confocal micrographs of localization of actin mRNA by in situ hybridization in 3-h light organs; similar results were obtained for samples at 6 and 12 h. The representative graph shows the relative fluorescence of hybridization to the actin antisense probes at 3 h. Data are the mean ± the standard error of the mean (n = 6). Bar, 15 μm. apo = aposymbiotic; sym = symbiotic.