. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MELANOGENESIS IX THK FIDDLKK CRAB 283. FIGURE 9a. Phase contrast optics, confluence of several melanophore processes, bar— 10 ft; 9b. As in Figure 9a, terminus of melanophore process, bar ==10 y.; 9c. as in Figure 9a, melanin granules in a fine process, bar == 10 /u- droxyphenylalanine (DOPA) and then to dopaquinone. Dopaquinone undergoes spontaneous oxidation and reduction reactions to yield indole-5,6-quinone. This compound is polymerized to form a large molecule which is thought to he bound through its quinone linkages to
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MELANOGENESIS IX THK FIDDLKK CRAB 283. FIGURE 9a. Phase contrast optics, confluence of several melanophore processes, bar— 10 ft; 9b. As in Figure 9a, terminus of melanophore process, bar ==10 y.; 9c. as in Figure 9a, melanin granules in a fine process, bar == 10 /u- droxyphenylalanine (DOPA) and then to dopaquinone. Dopaquinone undergoes spontaneous oxidation and reduction reactions to yield indole-5,6-quinone. This compound is polymerized to form a large molecule which is thought to he bound through its quinone linkages to the amino or sulfhydral groups of the protein matrix of the pigment granules (Mason, 1959. 1967; Duchon, Fitzpatrick and Seiji, 1968). Nicolaus, Piattelli and Fattorusso (1964) and Nicolatts and Piattelli (1965) (see also Mason, 1967; Duchon ct a!., 1CK>S) however, hypothesize that melanin is not homopolymeric (a regular polymer of idole-5,6-quinone) but consists of a random polymer (poikilopolymer ) of several different monomers including in part. DOPA. indole-5,6-quinone, and 2,3-dihydroxyindole. In either case the product melanin is water-insoluble and has incorporated into it the isotopic label. Tyrosinase is generally believed to occur in the matrix of the melanosome (Mover, 1963, Seiji, 1966). Thus the formation of melanin is presumptive evidence for the presence of tyrosinase and melanin granules. In the present work the localization of radioactivity derived from ::H-tyrosine over granules within the melanophore is evidence that melanogenesis occurs only in this cell. Melanogenesis apparently occurs independently of the state of pigment dispersion. The present technique, however, is not sensitive enough to detect short-term differences in the rate of melanin synthesis that may exist between melanophores with expanded. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearanc
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
