Gonadal macrophage aggregates in fish: A preliminary quantitative study in red mullet.

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.

Analysis and occurrence of some phenol endocrine disruptors in two marine sites of the northern coast of Sicily (Italy).

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 0.1-200ng/mL, with detection limits from 0.06 to 0.1ng/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.

Digestive enzymatic patterns as possible biomarkers of endocrine disruption in the red mullet (Mullus barbatus): A preliminary investigation.

During two seasonal trawl surveys (April and October, 2012), red mullet specimens were caught from two sites of the northern Sicilian coast (Western Mediterranean), characterized by different degrees of pollution, to assess whether their digestive enzymes could be cost-effective diagnostic tools for endocrine disruption. Pepsin, chymotrypsin, carboxypeptidases A and B, amylase and lipase were measured in the digestive tract of each fish. During both samplings, significant differences in the digestive enzymatic patterns of fish collected from the two sites were found. In April, pepsin and lipase contents were significantly lower in fish from the most impacted site than in those from the reference site. In October, the enzymatic patterns showed trends different from spring, with controversial results for carboxypeptidases A and B and amylase. Pepsin and lipase patterns suggest a detrimental effect played by organic pollutants and the use of these enzymes as possible biomarkers of exposure to endocrine disruptors.

Cholecystokinin: how many functions? Observations in seabreams.

A short overview on the regional distribution of the gastro-intestinal peptide hormone cholecystokin (CCK) in fish is presented. In particular, the results of molecular and immunological studies on seabreams, Diplodus puntazzo and Diplodus sargus, are reported, which, by demonstrating CCK in the hindgut, open new questions regarding the functional role of this hormone in that part of the intestine. The putative involvement of hindgut CCK in the feedback control of digestive processes was tested by measuring CCK gene and protein expression in fed and fasted fish. The results of this study led to hypothesize different roles for the two CCK isoforms in D. sargus, one of which related to regulation of digestive processes from pyloric caeca through hindgut. On the other hand, a functional role alternative to regulation of digestive processes may be inferred for the other isoform.

A histological study of ovarian development in the giant red shrimp Aristaeomorpha foliacea (Crustacea: Decapoda: Aristeidae) from the Southern Tyrrhenian Sea (Western Mediterranean).

The reproductive features of the giant red shrimp, Aristaeomorpha foliacea, were investigated in the southern Tyrrhenian sea by experimental trawl sampling. The annual length-frequency distribution showed a multimodal trend in females, ranging between 16 and 67 mm carapace length (CL), and a unimodal trend in males (18-45 mm CL). Mature males occurred in different proportions all year round, while females displayed seasonal maturity (June-September), with a peak in July. Six oocyte developmental stages were identified, the most advanced of which (Pv, postvitellogenic) had never been described before in this species. Ovary development followed a group-synchronous pattern, with the yolked oocyte stock clearly separated from the reservoir of unyolked oocytes, suggesting that A. foliacea is a total spawner, with determinate fecundity. Based upon histological findings, a revision of macroscopic maturity staging employed in Mediterranean bottom trawl surveys (MEDITS) is proposed.

Cholecystokinin in white sea bream: molecular cloning, regional expression, and immunohistochemical localization in the gut after feeding and fasting.

BACKGROUND: The peptide hormone cholecystokinin (CCK), secreted by the midgut, plays a key role in digestive physiology of vertebrates including teleosts, by stimulating pancreatic secretion, gut motility, and gallbladder contraction, as well as by delaying gastric emptying. Moreover, CCK is involved in the regulation of food intake and satiation. Secretion of CCK by the hindgut is controversial, and its biological activity remains to be elucidated. The present paper addresses the regional distribution of intestinal CCK in the white sea bream, Diplodus sargus, as well as the possible involvement of hindgut CCK in digestive processes. METHODOLOGY/PRINCIPAL FINDINGS: Full-lengths mRNAs encoding two CCK isoforms (CCK-1 and CCK-2) were sequenced and phylogenetically analyzed. CCK gene and protein expression levels in the different gut segments were measured 3 h and 72 h after feeding, by quantitative real-time RT-PCR and Western blot, respectively. Moreover, endocrine CCK cells were immunoistochemically detected. Fasting induced a significant decrease in CCK-2 in all intestinal segments, including the hindgut. On the other hand, no significant difference was induced by fasting on hindgut CCK-1. CONCLUSIONS/SIGNIFICANCE: The results demonstrated two CCK isoforms in the hindgut of D.sargus, one of which (CCK-2) may be involved in the feedback control of uncompleted digestive processes. On the other hand, a functional role alternative to regulation of digestive processes may be inferred for D.sargus CCK-1, since its expression was unaffected by feeding or fasting.

Ontogeny and distribution of cholecystokinin-immuno reactive cells in the digestive tract of sharpsnout sea bream, Diplodus puntazzo (Cetti, 1777), during larval development.

The appearance and regional distribution of cholecystokinin-immuno reactive cells (CCK-IR) in the developing gut of larval Diplodus puntazzo were studied by means of immunohistochemistry, with the aim of understanding the role of this peptide hormone in the acquisition of digestive capacity. Immunohistochemical reaction showed CCK-IR cells from 10 days after hatching (DAH), near the pyloric sphincter and past the first bend in the midgut, as well as in the hindgut. At 25 DAH CCK-IR cells were scattered throughout the midgut, as well as in the hindgut. Since gastric glands appeared at 30 DAH, CCK-IR cells were most abundant in the anterior midgut, near and including the pyloric caeca, and just afore the ileo-rectal sphincter in the posterior midgut, as well as in the hindgut. In older larvae (39 DAH), CCK-IR cells were mainly distributed in the anterior midgut, including the pyloric caeca, as well as in the hindgut. No CCK-IR cells were detected in the foregut at any stage. The distribution pattern of CCK-IR cells differed from other species which also possess a rotated gut as D. puntazzo. In fact, although cells were abundant in regions where the ingested food is retained, so that they can be stimulated to modulating the release of digestive enzymes, a large number of cells occurred also in the hindgut.

The ultrastructure of amberjack (Seriola dumerilii) sperm.

Scanning and transmission electron microscopy were used to investigate the fine structure of sperm of the Mediterranean amberjack Seriola dumerilii. Each spermatozoon has an ovoid head which lacks an acrosome, a short, irregularly-shaped midpiece and a long flagellar tail. The midpiece houses eight spherical mitochondria, which are separated from the axoneme by the cytoplasmic canal. The centrioles are arranged approximately at right angles to each other. The proximal centriole lies inside, and the distal centriole outside, the nuclear fossa. The flagellum is inserted eccentrically into the head and is tangential to the nucleus, so that the spermatozoon is asymmetrical. It contains the conventional 9 + 2 axoneme, shows intratubular differentiations in the A microtubules of doublets 1, 2, 5 and 6, and possesses one pair of lateral fins. On the basis of its ultrastructural organization, the amberjack sperm resembles type II sperm as defined previously, except for the presence of the proximal centriole inside the nuclear fossa. This could result from a partial rotation of the nucleus during spermiogenesis.