acid-phosphatase and Albinism

Two forms of cutaneous albinism in the chicken were investigated for the presence and distribution of tyrosinase and acid phosphatase in melanocytes in situ and in culture. In sex-linked recessive tyrosinase-positive albinism, sal, melanocytes in regenerating feathers and neural tube-derived cultures contained morphologically normal and abnormal premelanosomes. Tyrosinase was localized primarily to the abnormal premelanosomes and probably not to the normal ones. The cells possessed, in addition, vacuoles with membranous inclusions, located in the dendrites, and capped by dopa-positive vesicles (capping vesicles). Acid phosphatase colocalized with tyrosinase in the abnormal premelanosomes and capping vesicles. Tyrosinase activity in extracts of cultured sal melanocytes equalled that of e+ control melanocytes. A tyrosinase antiserum, raised against hamster tyrosinase (Pomerantz), precipitated 2 proteins, 68 kD and 82 kD, which had a precursor-product relationship. The amount of immunoprecipitate was the same in sal and control extracts, but in sal extracts the lower-molecular-weight protein was twice as abundant as the higher-molecular-weight protein. Melanocytes in regenerating feathers from an autosomal recessive, tyrosinase-negative albino, ca, also contained morphologically normal and abnormal premelanosomes. In culture, ca melanocytes had no formal premelanosomes but only dopa-negative multivesicular bodies with wispy filamentous material. Tyrosinase activity and immunoprecipitable tyrosinase were absent. These results suggest that: the tyrosinase-positive albino, sal, has an aberration in both its tyrosinase and acid phosphatase profiles and the tyrosinase-negative albino, ca, lacks functionally and antigenically normal tyrosinase.

Topics: Acid Phosphatase; Albinism; Animals; Catechol Oxidase; Cells, Cultured; Chickens; Feathers; Immunologic Techniques; Melanocytes; Monophenol Monooxygenase

The melanin macroglobule (MMG), formerly called "macromelanosome," is a cytoplasmic spherical granule formed in the melanocyte, varying in size from one to several microns, much larger than normal ellipsoidal melanosomes. Although ultrastructural features of MMG have been adequately described in the past, there has been a disagreement about the formation process of MMG. In order to further elucidate the nature and origin of MMG, electron microscopic studies were conducted in several pigmentary disorders. Our findings included: (1) The most remarkable characteristics of MMG are (a) the pleomorphism of their internal structure and (b) the variation of their size. (2) MMG do not represent true melanosomes but unique forms of autolysosomes resulting from the fusion of autophagosomes (containing various numbers of melanosomes) with primary and/or secondary lysosomes. (3) MMG are retained within melanocytes or transferred to keratinocytes and to Langerhans cells in the epidermis, and to macrophages in the dermis in any of their developmental stages. After transfer, MMG can fuse with other heterolysosomes and probably increase in size in these cells. We regard melanosome complexes as but one step in an autophagic process within melanocytes which can, on occasion, produce MMG as residual bodies.

Topics: Acid Phosphatase; Albinism; Autophagy; Biopsy; Eye Diseases; Histocytochemistry; Humans; Melanocytes; Microscopy, Electron; Microscopy, Electron, Scanning; Monophenol Monooxygenase; Neurofibromatosis 1; Nevus, Pigmented; Skin Neoplasms; Terminology as Topic

Topics: Acid Phosphatase; Albinism; Animals; Cathepsins; Female; Glucuronidase; Light; Lysosomes; Male; Radiation Injuries, Experimental; Rats; Retina

Topics: Acid Phosphatase; Adenine Nucleotides; Adenosine Diphosphate; Albinism; Aspirin; Blood Cell Count; Blood Platelet Disorders; Blood Platelets; Brain; Carbon Radioisotopes; Collagen; Factor X; Galactosidases; Glucuronidase; Heparin; Humans; Lysosomes; Microscopy, Phase-Contrast; Platelet Adhesiveness; Serotonin; Thrombin; Tissue Extracts; Venoms

Topics: Acid Phosphatase; Albinism; Alkaline Phosphatase; Animals; Ciliary Body; Epithelial Cells; Epithelium; Glucosephosphate Dehydrogenase; Histocytochemistry; Iris; Isocitrate Dehydrogenase; Microscopy, Electron; Pigmentation; Pinocytosis; Rabbits; Staining and Labeling; Succinate Dehydrogenase

Topics: Acid Phosphatase; Albinism; Animals; Chloroquine; Cytoplasmic Granules; Histocytochemistry; Lysosomes; Male; Melanins; Microscopy, Electron; Rats; Retina

Topics: Acid Phosphatase; Adolescent; Adult; Albinism; Animals; Child; Culture Techniques; Cytoplasmic Granules; Female; gamma-Globulins; Glycolipids; Guinea Pigs; Hematologic Diseases; Heterozygote; Homozygote; Humans; Immunodiffusion; Immunoelectrophoresis; Interferons; Leukocytes; Lymphocytes; Lysosomes; Male; Mice; Peroxidases; Phagocytosis; Prednisone; Rabbits; Suspensions; Vincristine