The emergence of pigment cell biology: a personal view

This is a semi-autobiographical coverage of my research career in pigment cell biology presented in the context of the emergence and growth of the discipline. This anecdotal presentation tells about some historical personages in the field. My undergraduate studies at the University of Rochester are related to my graduate work at the University of Iowa. I tell how my dissertation research was derived from a marriage between my interests in experimental embryology and the new field of comparative endocrinology. My early years of research at Iowa and as a young faculty member in Zoology at the University of Arizona were much concerned with the evolution of our knowledge of the chemistry and biology of melanocyte-stimulating hormone (MSH), especially concerning the pigment cells of lower vertebrates. Our developmental, structural, functional, and biochemical characterization of vertebrate chromatophores is described, as is our elucidation of the dermal chromatophore unit. The direct effects of light on changes in pigmentation are considered in descriptions of both the tail-darkening reaction and the role of the pineal gland in melanophore control. Emphasis is placed on the developmental biology of pigmentation, especially on the concept that all pigment cells are derived in common from a stem cell of neural-crest origin, whose expression is influenced by factors, such as melanization-inhibiting factor (MIF), localized in specific areas of the skin to thus produce specific pigmentation patterns. This research is considered in light of what is known about the agouti locus and MSH in the expression of mammalian pigmentation patterns. Part of my work has included ecological considerations, and some of this is touched upon. My role as founder of the journal 'Pigment Cell Research', is presented briefly, as is my involvement in the XIIIth International Pigment Cell Conference and in the establishment of both the International Pigment Cell Society and the International Federation of Pigment Cell Societies. Finally, I comment on the future of research in pigmentation.

[From butterflies to neurobiology and the diagnosis of AIDS. The 100th anniversary of the discovery of pteridines]

The first report on the isolation of pteridines from biological materials was published in 1889. During the last 100 years a large number of pteridines have been isolated from many different organisms and have been shown to be involved in several biochemical processes. The best characterized biologically occurring unconjugated pteridine, i.e. tetrahydrobiopterin, is a cofactor for amino acid hydroxylases, such as phenylalanine, tyrosine and tryptophan hydroxylase. The last two enzymes catalyze the rate-limiting steps in the synthesis of important biogenic amines, such as dopamine, noradrenaline, adrenaline and serotonin. Several inborn errors in the biosynthesis of tetrahydrobiopterin have provided more insight into variant forms of phenylketonuria (Følling's disease). Recently, it has been shown that pteridines also are involved in immunological responses, and neopterin has been suggested as a diagnostic marker for malignancies, virus infections and acute rejection episodes following allotransplantation.