Distribution of copper and zinc in the eyes of fresh-water fishes and frogs. Occurrence of metals in melanin fractions from eye tissues

Bowness, J. M.; Morton, R. A.

doi:10.1042/bj0510530

Cited by 44 publications

(8 citation statements)

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“…We assume two reasons to understand this observation. Indeed, field investigations have already shown that the highest concentration of Zn can be found in the eyes of fish (Bowness and Morton, 1952;Eckhert, 1983) although the exact function(s) of Zn in the eye remains to be clarified. suggested as the major Zn excretory route in euryhaline fish exposed through dietary Zn (Hardy et al, 1987).…”

Section: Resultsmentioning

confidence: 99%

Dietary Zn and the subsequent organotropism in fish: No influence of food quality, frequency of feeding and environmental conditions (pH and temperature)

et al. 2017

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Trophic transfer of Zn in fish is affected by the type of food and environmental variables such as temperature. However, there is still a lack of knowledge regarding the effects of such factors on Zn organotropism. For this reason, a series of experimental studies have investigated how the distribution and the concentration of Zn is affected by some environmentally-relevant factors (food quality, food availability, water pH, and temperature) in turbot Scophthalmus maximus using radiotracer techniques. In three different experiments, Zn distribution in seven body compartments of juvenile turbot and the calculation of Zn concentration index (I) for each compartment were compared. Its distribution as well as its concentration in the body compartments of juvenile turbots were not affected by the experimental conditions tested. This apparent consistency in the Zn organotropism can be explained by the ability of the fish to maintain Zn homeostasis at non-toxic Zn concentrations in their diet. These results are important to better understand the trophic transfer of Zn in fish under realistic environmental conditions.

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Section: Resultsmentioning

confidence: 99%

Dietary Zn and the subsequent organotropism in fish: No influence of food quality, frequency of feeding and environmental conditions (pH and temperature)

et al. 2017

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“…These substituents allow melanin pigments to selectively bind positively charged particles, like the transition metals, and sequester them in the pigmented cells of hair, skin, and feathers (Borovansky et al 1976, Borovansky 1994, Bilinska 2001). As a result, these minerals accumulate in high concentrations within melanized tissues, specifically within the pigment‐cell organelles (melanosomes; Shibita et al 1993), such as the mammalian retina (Salceda and Sanchez‐Chavez 2000) and hair (Tobin and Paus 2001), the eyes of fishes and frogs (Bowness and Morton 1952), and bird feathers (Niecke et al 1999). For example, Niecke et al (1999) showed that black, melanin‐pigmented feathers in white‐tailed eagles ( Haliaeetus albicilla ) were particularly enriched with Ca, Mn, and Zn compared to white feathers.…”

Section: Melanin Polymers As Chemoprotective Reservoirsmentioning

confidence: 99%

Melanins, metals, and mate quality

2003

Oikos

105

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Many animals display large patches of black or brown color in their integument, which contain melanin pigments and function as important sexually selected indicators of mate quality. To date, however, the particular means by which melanin‐based color ornaments are costly to produce and serve as honest advertisements have remained elusive. Here, I propose a novel biochemical mechanism by which melanin‐based coloration may serve as a reliable indicator of quality, involving the interplay of metal ions. In animals and other biochemical systems, a series of scarce macro‐ and microminerals (e.g. Ca, Zn, Cu, Fe) obtained from the diet act as critical regulatory factors in the biosynthesis of eumelanin and phaeomelanin pigments, but can also be toxic to the body when accumulated in high concentrations. As large polymers with many functional (carboxyl) groups, melanin granules also bind these metals and store them in pigmented cells. Thus, by sequestering large deposits of melanin, often in dead tissue (as in hair or feathers), animals may directly reveal dietary access to these rare elements and the physiological protection they have afforded themselves from initially beneficial, but eventually damaging, high mineral concentrations.

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“…Counts made in different years are not strictly comparable, as different microscopes and different magnifications were used. The melanin content of the bodies of the experimental larvae was determined using a modification of a method described by Bowness 8c Morton (1952). The Iarvae were reared in the thyroid drugs at constant temperature for 19 days after hatching; at the end of this period 10 larvae were removed and killed by spinal section, their heads cut off immediately behind the operculum, the yolk sac and gut dissected away, and the bodies immediately deep frozen to await analysis.…”

Section: Methodsmentioning

confidence: 99%

Effects of thyroid drugs on the larvae of the Brown trout, Salmo trutta

Woodhead

1966

Journal of Zoology

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Brown trout larvae, Salmo trutta L., were reared from hatching in solutions of the thyroid hormone, thyroxine, and the thyroid inhibitors, thiourea and thiouracil. Thyroxine treatment profoundly affected morphogenesis, while thiourea and thiouracil had little morphogenic effect. Thyroxine treatment caused abnormal growth of the head, and stimulated the rate of differentiation of the fins from the primitive fin fold, and the absorption of the external yolk sac. The epidermis and dermis were considerably thicker in thyroxine‐treated larvae than in control fish, and silvering of the skin was induced. Thiourea and thiouracil produced few morphogenic effects, but such effects as were evident were usually similar with both drugs, and opposite to those caused by thyroxine treatment.

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Distribution of copper and zinc in the eyes of fresh-water fishes and frogs. Occurrence of metals in melanin fractions from eye tissues

Cited by 44 publications

References 1 publication

Dietary Zn and the subsequent organotropism in fish: No influence of food quality, frequency of feeding and environmental conditions (pH and temperature)

Dietary Zn and the subsequent organotropism in fish: No influence of food quality, frequency of feeding and environmental conditions (pH and temperature)

Melanins, metals, and mate quality

Effects of thyroid drugs on the larvae of the Brown trout, Salmo trutta

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