Exposure to heavy metals can produce morphological and functional alterations in fish. It is well known that the marine organisms living in contaminated environments display damage attributable to the structures most directly exposed to the external environment such as the branchial epithelium, and thus involved in the interactions between it and the organism. The aim of the present work is to determine useful biomarkers in Liza aurata for identification of anomalies due to the toxic agents and factors implicated in the mechanisms controlling osmoregulation, detoxification, respiration and neurotransmission. The study of these biomarkers is an important ecophysiological factor and a tool for evaluating the risk of environmental variations in the coastal species exposed to anthropic pollution. Specimens of the golden grey mullet L. aurata (Perciformes, Mugilidae) were collected from the brackish swamps of Faro and Ganzirri (Messina, Italy), considered highly polluted environments; instead, the specimens collected from the Marinello (ME) and Fogliano (LT) swamps, considered a reference site, were used as the control group. In the branchial epithelium of specimens collected from highly polluted environments, in comparison with the control group, a decrease in immunoreactivity for serotonin was found, together with, the presence of a few apoptotic nuclei, revealed by TUNEL technique. The increased immunopositivity for nNOS is probably due to stress conditions. The local reaction to hypoxia involves a more intense production of vasoactive substances, like NO, by nitrergic innervation. In the specimens living in polluted environments, immunopositivity for metallothioneins and iNOS in the chloride cells is very interesting. The presence of both substances may be considered a further defensive mechanism also related to the significantly higher concentration of Pb found in gills and kidney. The results obtained show that, in stressed fish, the defensive processes increase to maintain the normal functions of the organs more exposed to the action of polluted substances.

Stress factors in the gills of Liza aurata (Mugilidae, Teleosts) living in polluted environments

MAUCERI, Angela Rita;MINNITI, Francesco;MAISANO, Maria;LO CASCIO, Patrizia;FASULO, Salvatore
2005-01-01

Abstract

Exposure to heavy metals can produce morphological and functional alterations in fish. It is well known that the marine organisms living in contaminated environments display damage attributable to the structures most directly exposed to the external environment such as the branchial epithelium, and thus involved in the interactions between it and the organism. The aim of the present work is to determine useful biomarkers in Liza aurata for identification of anomalies due to the toxic agents and factors implicated in the mechanisms controlling osmoregulation, detoxification, respiration and neurotransmission. The study of these biomarkers is an important ecophysiological factor and a tool for evaluating the risk of environmental variations in the coastal species exposed to anthropic pollution. Specimens of the golden grey mullet L. aurata (Perciformes, Mugilidae) were collected from the brackish swamps of Faro and Ganzirri (Messina, Italy), considered highly polluted environments; instead, the specimens collected from the Marinello (ME) and Fogliano (LT) swamps, considered a reference site, were used as the control group. In the branchial epithelium of specimens collected from highly polluted environments, in comparison with the control group, a decrease in immunoreactivity for serotonin was found, together with, the presence of a few apoptotic nuclei, revealed by TUNEL technique. The increased immunopositivity for nNOS is probably due to stress conditions. The local reaction to hypoxia involves a more intense production of vasoactive substances, like NO, by nitrergic innervation. In the specimens living in polluted environments, immunopositivity for metallothioneins and iNOS in the chloride cells is very interesting. The presence of both substances may be considered a further defensive mechanism also related to the significantly higher concentration of Pb found in gills and kidney. The results obtained show that, in stressed fish, the defensive processes increase to maintain the normal functions of the organs more exposed to the action of polluted substances.
2005
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/1889527
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