The characteristic dark color of Diadema antillarum is chiefly attributable to a black pigment, most of which is contained in large epidermal chromatophores (see Fig. 1). A red pigment is also present, but is easily separable from the black, being readily soluble in ethanol and acetone, whereas the black is not. The nature of the red pigment is unknown and we have not studied its properties. Co...

Mating behaviour and predation avoidance in Heliconius involve visual colour signals; however, there is considerable inter-individual phenotypic variation in the appearance of colours. In particular, the red pigment varies from bright crimson to faded red. It has been thought that this variation is primarily due to pigment fading with age, although this has not been explicitly tested. Previous ...

In pernicious anemia and hemochromatosis an iron-containing pigment, hemosiderin, ordinarily derived from hemoglobin, is deposited in organs free from such pigment in most conditions that involve blood destruction. When sudden hemolysis takes place in a previously healthy human being, as after cutaneous burns or the action of a "blood poison," hemosiderin granules appear in the spleen, the red ...

It has long been known that visible radiations exert direct control over the growth and development of plants by photoreactions other than those involved in photosynthesis. In recent years it has become clear, primarily through the determination of .action spectra, that several of these apparently unrelated processes may have a common photoreceptor. For exanmple, the action spectra for the inhi...

In a previous paper [1] we discussed biliverdin IXa as an intermediate of phycocyanobilin biosynthesis (also compare [2—4]). The experiments involved the incubation of red algae of the species Cyanidium caldarium III-D-2 with the tetrapyrrole precursor 5-aminolevulinic acid. After 2—3 days incubation we observed as a main product a rather polar blue pigment of an as yet unknown structure in the...

The present study is designed to evaluate the application of a simple method for rapid identification of Malassezia furfur among other Malassezia spp. based on production of a brownish-red pigment and its diffusion into the medium containing L-tryptophan as a sigle source of nitrogen.  91 strains of Malassezia (20% M. furfur, 2% M. sympodialis, 5% M. obtosa and 73% M. globosa) isolated from ski...

Lawrence et al (4) identified the red pigment in bracts of poinsettia as an anthocyanin. The methods employed served to identify the principal anthocyanidin (cyanidin), but not the sugar moiety. Blank (2), Robinson and Robinson (5, 6, 7), and Scott-'Moncrieff (8) reported that variation in the sugar moiety of the anthocyanin pigment affected color. They found that monoglycosides were redder tha...

A variant designated "cherry-red" is frequently observed in common flue-cured tobacco varieties. This variant has a dappled red coloration of the cured leaf. Cherry-red and red-free selections have been obtained from Nicotiana tabacum, L. cv. 401. Analysis of these selections for alkaloids showed that the cherry-red selection had a much higher nornicotine content than the red-free selection. Co...