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Melatonin as an antioxidant: biochemical mechanisms and pathophysiological implications in humans

100%

Reiter R. J., Tan D., Mayo J. C., Sainz R. M., Leon J., Czarnocki Z.

Acta Biochimica Polonica

2003

tom 50

nr 4

This brief resume enumerates the multiple actions of melatonin as an antioxidant. This indoleamine is produced in the vertebrate pineal gland, the retina and possibly some other organs. Additionally, however, it is found in invertebrates, bacteria, unicellular organisms as well as in plants, all of which do not have a pineal gland. Melatonin's functions as an antioxidant include: a), direct free radical scavenging, b), stimulation of antioxidative enzymes, c), increasing the efficiency of mitochondrial oxidative phosphorylation and reducing electron leakage (thereby lowering free radical generation), and 3), augmenting the efficiency of other antioxidants. There may be other functions of melatonin, yet undiscovered, which enhance its ability to protect against molecular damage by oxygen and nitrogen-based toxic reac- tants. Numerous in vitro and in vivo studies have documented the ability of both physiological and pharmacological concentrations to melatonin to protect against free radical destruction. Furthermore, clinical tests utilizing melatonin have proven highly successful; because of the positive outcomes of these studies, melatonin's use in disease states and processes where free radical damage is involved should be increased.

Effect of single superphosphate fertilizer on survival and respiratory dynamics of Nile Tilapia, Oreochromis niloticus [Actinopterygii: Perciformes: Cichlidae]

70%

Omoregie E., Ajima M. N. O., Keke R. I., Wieski K.

Acta Ichthyologica et Piscatoria

2009

tom 39

nr 2

103-110

Background. Increasing global usage of inorganic fertilizers, including phosphate-based fertilizers has its negative consequences on the aquatic environment. Effects of single superphosphate fertilizer (SPF) remain unknown, particularly its influence on the respiratory dynamics of fish under continuous exposure. We investigated the effects of single SPF on the survival and respiratory dynamics of Nile tilapia, Oreochromis niloticus, under laboratory conditions. Materials and Methods. Nile tilapia fingerlings (of mixed sex) (5.40 . 0.03 g) were exposed to various concentrations of the fertilizer in five treatment regimes (in triplicate): 0.88, 1.75, 3.50, 7.00, 14.00 g . L–1 (and 0.00 g . L–1 for control). Each replicate was carried out in a 30-L circular plastic tank based on 20 fingerlings. The study involved: the mortality estimation, the oxygen consumption, the histopathological effects on fish gills, and the activities of lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH) in liver of fish exposed to sublethal concentrations (0.44, 0.22, 0.11, 0.06, and 0.03 g . L–1) of single SPF for eight weeks under laboratory conditions. Results. Acute concentrations of SPF had serious adverse effects on mortality, oxygen consumption and opercular ventilation rates of exposed fish. All variables showed a dose-dependency. A mean value of 96-h LC50 of the SPF to the test fish was calculated to be 3.76 g . L–1. At various acute concentrations, oedema and hyperplasia of gill lamellae were observed in exposed fish. Exposure of the fish to sublethal concentrations of the SPF resulted in reduction in the levels of lactate dehydrogenase and alcohol dehydrogenase activities in liver. Conclusion. Concentrations of SPF in natural water bodies are deleterious to aquatic fauna. With rapid global economic development and need for more food production, pollution from agricultural fertilizers remains a major threat to the aquatic ecosystem. Therefore it is ultimately important that a balance is struck between achieving economic excellence and environmental protection through good pollution management strategies.

Ograniczanie wyników

1 Acta Biochimica Polonica

1 Acta Ichthyologica et Piscatoria

1 Ajima M. N. O.

1 Czarnocki Z.

1 Keke R. I.

1 Leon J.

1 Mayo J. C.

1 Omoregie E.

1 Reiter R. J.

1 Sainz R. M.

1 Tan D.

1 Wieski K.

1 2009

1 2003

Wyniki wyszukiwania

Melatonin as an antioxidant: biochemical mechanisms and pathophysiological implications in humans

Effect of single superphosphate fertilizer on survival and respiratory dynamics of Nile Tilapia, Oreochromis niloticus [Actinopterygii: Perciformes: Cichlidae]