Betacyanins and anthocyanins, two main red fl ower pigments, never occur together in the same plant. Although the anthocyanin biosynthetic pathway has been well analyzed, the biosynthetic genes and the regulatory mechanism of the betacyanin biosynthesis are still obscure. We cloned two cDNAs of DOPA dioxygenase from Phytolacca americana, PaDOD1 and PaDOD2, that may be involved in the betalain biosynthesis. The deduced amino acid sequence of PaDOD1 and PaDOD2 showed approximately 80% homology to each other. The promoter regions of PaDOD1 and PaDOD2 were isolated by inverse PCR and analyzed using PLACE database. Some putative MYB, bHLH, and environmental stress-responsive transcription factor binding sites were detected in the PaDOD1 and PaDOD2 promoter regions. Expression patterns of PaDOD1 and PaDOD2 in suspension cultures of P. americana were investigated by semiquantitative RT-PCR. The transcripts of PaDODs were found in both betacyanin-producing red cells and non-betacyanin-producing white cells, suggesting that not only the expression of DOD, but also the supplementation of DOPA might be a regulatory step for the betalain biosynthesis in P. americana.

We experimentally verified a method by which a liquid that has entered a long pore with open ends can be removed from the pore by using the acoustic radiation force produced by high-intensity aerial ultrasonic waves at a frequency of 20 kHz. The intensity of the ultrasonic waves was about 6 to 10 kPa. By using this method, it was confirmed that a liquid in pores of 1.5 to 5.0 mm diameter and 3 to 20 mm length could be instantaneously removed from the pores. This method, which did not use any air flow at a high pressure, has the significant advantage that it does not produce any strong air flow around the pore. We consider the intensity of the ultrasonic waves required to remove the liquid, the time required to remove the liquid, and the quantity of liquid removed, all of which were determined by varying the diameter and length of the pore.