Betalains of Celosia argentea

The betalains of yellow, orange and red inflorescences of common cockscomb (Celosia argentea var. cristata) were compared and proved to be qualitatively identical to those of feathered amaranth (Celosia argentea var. plumosa). In addition to the known compounds amaranthin and betalamic acid, the structures of three yellow pigments were elucidated to be immonium conjugates of betalamic acid with dopamine, 3-methoxytyramine and (S)-tryptophan by various spectroscopic techniques and comparison to synthesized reference compounds; the latter two are new to plants. Among the betacyanins occurring in yellow inflorescences in trace amounts, the presence of 2-descarboxy-betanidin, a dopamine-derived betacyanin, has been ascertained. The detection of high dopamine concentration may be of toxicological relevance in use of yellow inflorescences as a vegetable and in traditional Chinese medicine, common uses for the red inflorescences of common cockscomb.     

Large changes in the population of cell wall proteins accompany the shift to cell elongation

The expression patterns of cell wall proteins in mung bean hypocotylsboth before and during cell elongation have been investigated.The results suggest two clear conclusions. First, it is shownthat there is a large population of cell wall-specific proteins(at least 20 abundant ones and perhaps as many as 250 minorones) detectable on 2-D gels. Second, of these proteins morethan half differ markedly in their levels of expression betweennon-elongating or elongating cells in the hypocotyl tissue.Some are up-regulated while others are down-regulated. Variouscontrols ensure that cytosolic contamination is minimal andthat the changes seen represent real switches in cell wall proteinexpression. The results indicate that this approach providesa sound strategy for the future identification and characterizationof cell wall proteins specifically associated with cell elongation. Key words: Cell wall proteins, plant cell elongation, 2-D gels, mung bean, extension growth