Black Moor Research Articles

Failure of cAMP to replace ACTH in over-riding the melanosome aggregation effect of epinephrine

Epinephrine-induced melanosome aggregation in cultured terminally differentiated Black Moor goldfish melanophores can be over-ridden by ACTH but not by cAMP.

The myopic eye of the black moor goldfish

Optical and anatomical methods were used to establish the refractive state of the eye of the Black Moor variety of goldfish. The eye is strongly myopic. The refractive error in 12 eyes from 6 fish ranged from 89 to 268 D.

Horizontal cell axons and axon terminals in goldfish retina.

Retinas of ordinary and black moor varieties of goldfish (Carassius auratus) were prepared by the Golgi method, mounted flat or sectioned vertically, and studied in the light microscope. Three types of horizontal cells whose dendrites contact only cones, and one type whose dendrites contact only rods, were observed. The cone horizontal cells (Cajal's "external horizontal cells") all have slender axons which descend gradually to the inner nuclear layer and terminate there in long, fusiform expansions (Cajal's "internal horizontal cells"). The thin and thick portions of the axons, as well as the perikarya of the horizontal cells, bear small numbers of straight, horizontally-directed, knobby filamentous appendages which may be sites of synaptic contact. The cone horizontal cell axons in goldfish, unlike those in higher vertebrates, do not terminate in contact with synaptic endings of photoreceptor cells, but in proximity to cells and processes deep in the inner nuclear layer. Axons have not yet been demonstrated on rod horizontal cells in goldfish.

Pigment cell differentiation in albino goldfish. I. Ultrastructural differentiation of retinal pigment epithelium.

The fine structural differentiation of the retinal pigment epithelium of the albino goldfish (Carassius auratus) in several developmental stages and in the adult was studied. In the 5-mm larva, the retinal pigment cells contained granules whose cores are filled with conglomerates of electron-dense pigments, but they were never pigmented fully as in the control black moor goldfish. Most of the granules have a round or ovoid shape, but granules with an elongate, cigar-like form are occasionally observed. The internal membranous frame-work, which has been reported in unpigmented and lightly pigmented granules in melanocytes of other vertebrates, was rarely observed in the present study. The number of pigment granules increased during the early developmental stages, whereas they decreased conspicuously in the later stages.

Tyrosinase activity of the melanin and pteridine granules in goldfish chromatophores

1. 1. The melanin granules within the melanophore and the pteridine granules within the erythrophore in the adult skin of four colored varieties (black moor, red, white and calico) of goldfish, Carassius auratus L were separated by the method of low-speed density gradient centrifugation. 2. 2. It has been demonstrated that the melanin granules are free of tyrosinase activity and probably of pteridine derivatives and that the pteridine granules are the carriers of pteridine derivatives and tyrosinase. 3. 3. The location of tyrosinase has been demonstrated morphologically: (1) the melanization of erythrophores has been induced; (2) further melanization did not occur in the melanophores; (3) no amelanotic melanophores have been observed.

Adrenergic neurons in teleost retina.

The adrenergic retinal neurons of perch and trout were studied with the fluorescence microscopical method of Falck and Hillarp. Pilot studies were also performed on pike, plaice, cod, eel, goldfish, cunner, black moor, cichlid and carp. Only minor differences were noted between the species.

Tyrosinase activity in goldfish skin.

SummaryThe tyrosinase activity in 4 varieties of goldfish (Carassius auratus L.), white, xanthic, grey and black moor, was determined. Tyrosinase activity occurred in both the soluble and particulate fractions of skin homogenates. Total tyrosinase activity was increased in both fractions with increasing melanin pigmentation. The activity increase, however, occurred, for the most part, in the particulate fraction. White and xanthic goldfish were identical in tyrosinase content and distribution. Tyrosinase activity in black moor skin is: skin to fin ratio, 4:1; dorsal skin to ventral skin ratio, 4:1; right side to left side ratio, 1:1. Further, smaller fish have a higher skin tyrosinase level than larger fish.

Tyrosinase of the goldfish Carassius auratus L : II. Correlation of tyrosinase activity with pigmentation

1. 1. It has been demonstrated that during stress-induced melanogenesis in the goldfish, Carassius auratus L, the level of tyrosinase in the skin is increased several fold and that this increase precedes pigmentation. 2. 2. The increase in tyrosinase activity is more pronounced in the particulate fraction than in the soluble fraction. 3. 3. In three varieties of the goldfish (xanthic, wild-type grey and black moor), the tyrosinase activity parallels the degree of pigmentation of the skin. This is due to a higher level of particulate tyrosinase in the pigmented fish. 4. 4. Considerable tyrosinase activity is present in skin homogenates prepared from totally xanthic fish. Therefore, in addition to the level of tyrosinase activity, other factors may regulate melanogenesis.