Mammalian and plant purple acid phosphatases have similar active site structures despite low sequence identity (<20%). Although no bacterial enzyme has been purified, a sequence database search revealed that genes that could encode potential purple acid phosphatases may be restricted to a small number of organisms (i.e. myco- and cyanobacteria). Analysis of their deduced amino acid sequences an...

We located a heavy metal label, mercurilated phenylglyoxal, in both the primary sequence and in the tertiary structure of bacteriorhodopsin. This label modified arginines 225 and 227, which are on the COOH-terminal helix (G). In the projected electron potential difference map, the major site is close to the central inner helix. From this result we conclude that helix 1 could not be the COOH-ter...

The purple membrane is a two-dimensional crystalline lattice formed by bacteriorhodopsin and lipid molecules in the cytoplasmic membrane of Halobacterium salinarum. High-resolution structural studies, in conjunction with detailed knowledge of the lipid composition, make the purple membrane one of the best models for elucidating the forces that are responsible for the assembly and stability of i...

Aerial predator-prey interactions may impact populations of many terrestrial species. Here, we use altitude loggers to study aerial foraging in a native insectivore, the purple martin (Progne subis), in the southern USA. Purple martins fed primarily on mating queens and males of the invasive red imported fire ant (Solenopsis invicta), and doubled their foraging efficiency by doing so. Across th...

The genotypic variation on physico-chemical characteristics of wild grown plums (Prunus spinosa L.) was investigated. The total phenolic contents were in a range of 117 to 407 mg GAE/100 g FW. The vitamin C was highest in yellow colored fruits (12.10 mg/100 ml). The total soluble solid content varied between 9.40% (yellow colored) and 12.90% (dark purple colored) fruits.  Antioxidant activity o...

Purple corn (Zea mays L.), a grain with one of the deepest shades in the plant kingdom, has caught the attention of the food industry as it could serve as a source for alternatives to synthetic colorants. Also being rich in phenolic compounds with potential health-promoting properties, purple corn is becoming a rising star in the novel ingredients market. Although having been widely advertised ...

1. Measurements of visual purple regeneration in solution have been made by a procedure which minimized distortion of the results by other color changes so that density changes caused by the regenerating substance alone are obtained. 2. Bleaching a visual purple solution with blue and violet light causes a greater subsequent regeneration than does an equivalent bleaching with light which lacks ...

THE SEA HARE is probably best known because of the red to purple fluid secreted from the margin of its mantle. There is only a superficial resemblance between this secretion and that of the genus Mttrex, which is the source of the anciently famous dye, "Tyrian" or "Royal Purple." Aplysia purple, however, found no practical use, probably because of one important deficiency-it turns a dirty brown...