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A histological study was conducted in red mullet, Mullus barbatus, collected from two sites characterized by different anthropogenic impacts. The aim of the study was to assess sex-, size-, season- and site-related variation in gonadal macrophage aggregate (MA) size, number, and relative area. Gonadal MAs were most abundant in males than in females. The number of MA was significantly higher in males from the most impacted site in October, with larger individuals showing more MA than smaller ones. MAs were always found in ripe testes, whereas they occurred only in regressing ovaries. These preliminary findings suggest that the presence of ovarian MA in red mullet is most likely related to ovary regression after spawning, whereas the presence of testicular MA is not necessarily associated to gonad regression, and may vary with season, size, and water quality.

A histological study was conducted in red mullet, Mullus barbatus, collected from two sites characterized by different anthropogenic impacts. The aim of the study was to assess sex-, size-, season- and site-related variation in gonadal macrophage aggregate (MA) size, number, and relative area. Gonadal MAs were most abundant in males than in females. The number of MA was significantly higher in males from the most impacted site in October, with larger individuals showing more MA than smaller ones. MAs were always found in ripe testes, whereas they occurred only in regressing ovaries. These preliminary findings suggest that the presence of ovarian MA in red mullet is most likely related to ovary regression after spawning, whereas the presence of testicular MA is not necessarily associated to gonad regression, and may vary with season, size, and water quality.

The peptide hormone cholecistokinin (CCK) plays a key role in the central and peripheral nervous system. It is known to be involved in the digestive physiology and in the regulation of food intake. Moreover, the CCK expression has also been detected in the retina of different vertebrates, including fish, although its biological activity in this tissue remains to be elucidated. In literature no data are yet available about the CCK-immunoreactivity in the zebrafish retina during development. Therefore, the aim of the study was to investigate the distribution of sulfated cholecystokinin octapeptide (CCK8-S) as a well preserved form during evolution in the zebrafish retina from 3 days post hatching (dph) until adult stage, using immunohistochemistry in order to elucidate the potential role of this protein in the development and maintenance of normal retinal homeostasis. The cellular distribution of CCK in the retina was similar from 3 dph to 40 days post fertilization (dpf) when immunoreactivity was found in the photoreceptors layer, in the outer plexiform layer, in the inner plexiform layer and, to a lesser extent, in the ganglion cell layer (GCL). Immunohistochemical localization at 50 dpf as well as in the adult stage was observed in a subpopulation of amacrine cells in the proximal inner nuclear layer, in the inner plexiform layer, in displaced amacrine cells and in retinal ganglion cells in the GCL. Our results demonstrate for the first time the occurrence of CCK in the zebrafish retina from larval to adult stage with a different pattern of distribution, suggesting different roles of CCK during retinal cells maturation.

This study reports the occurrence of some endocrine disrupting chemicals in red mullet samples and sediments collected in two representative sites of the northern Sicilian coast (Italy). For this purpose, an improved method, using solid extraction and high-performance liquid chromatography analyses for the simultaneous determination of bisphenol A (BPA), 4-nonylphenol (4-NP) and 4-t-octylphenol (4-t-OP) in fish tissues and sediments, has been developed and validated. Method performance was demonstrated over the concentration range 0.1–200 ng/mL, with detection limits from 0.06 to 0.1 ng/mL. Recoveries ranged from 83.4% to 102.6%, with relative standard deviations of 7.7–14.0% for the entire procedure. Results showed that BPA, 4-t-OP and 4-NP were detected in all fish samples and sediments from two sampling sites, indicating that these chemicals have contaminated Mediterranean aquatic ecosystem and have accumulated in fish. The study provided more comprehensive fundamental data for risk assessment and contamination control of phenolic EDCs in aquatic environment.