Search

Cutaneous neoplasms affecting wild striped bream (Lythognathus mormyrus) have been recorded after their introduction in a marine aquaculture farm in the Adriatic Sea. The tumors were evident on 24% of the reared fish, showing single or multiple nodules, with a diameter ranging between 0.5–4.0 cm. Histologically, all the neoplastic lesions were located in the stratum spongiosum of the dermis and were surrounded by a thin capsule of connective tissue. The tumors were predominantly composed of adipocytes grouped and surrounded by a thin net of fibroblasts and collagen fibers. In some lipomas a mixture of adipocytes and uniform spindle cells were also observed. Fibroblasts and collagen fibers, or spindle cells, showing few mitotic figures were mainly observed in other nodules. Three of the tumors showed bands of cells with elongated nuclei. Five neoplasms differed from the classic spindle cell lipoma due to the presence of scattered giant cells. These cells presented acidophilic abundant cytoplasm with multiple hyperchromatic nuclei showing a concentric “floret-like” arrangement. The tumors were further characterized by ultrastructural observations that allowed ruling out the presence of virus-like particles within the lesions. Histological features of the masses lead to the identification of four prevalent patterns of neoplasms: lipoma, fibrolipoma, spindle cell lipoma (SCL), and atypical spindle cell-like lipoma (ASCL). The different neoplasms could arise from the transformation of mesenchymal cells of dermal origin. To the author’s knowledge, this is the first report describing key differential histological and ultrastructural features of these neoplasms in striped sea bream.

The comber alphavirus was isolated from a fish cell line from the brain of an apparently healthy Serranus cabrilla specimen collected during wild fish surveillance in southern Italy. The comber alphavirus is a new member of the genus Alphavirus, family Togaviridae.

The comber alphavirus was isolated from a fish cell line from the brain of an apparently healthy Serranus cabrilla specimen collected during wild fish surveillance in southern Italy. The comber alphavirus is a new member of the genus Alphavirus , family Togaviridae .

Raphidascarididae are among the most abundant and widespread parasitic nematodes in the marine environment. The life-cycle of most raphidascaridid species is poorly known and information about their distribution and host range is lacking in many geographical areas, as is the taxonomy of several species. A study of larval and adult stages of Hysterothylacium fabri (Rudolphi, 1819) Deardorff and Overstreet, 1980 (Nematoda: Raphidascarididae) infecting the striped goatfish Mullus surmuletus Linnaeus, 1758 (Mullidae) and the Mediterranean stargazer Uranoscopus scaber Linnaeus, 1759 (Uranoscopidae) from the Ionian Sea (central Mediterranean) has been carried out by combining light and scanning electron microscopy observations and molecular analyses through polymerase chain reaction-restriction fragment length polymorphism and sequencing of the ITS rDNA gene. Results indicate that U. scaber and M. surmuletus represent suitable definitive and intermediate/paratenic hosts of H. fabri, respectively, in the Mediterranean and highlight the importance of combining genetic and morphological data to study the taxonomy and epidemiology of parasites widely distributed in different fish species and aquatic ecosystems.

Viral encephalopathy and retinopathy (VER) is one of the most devastating diseases for marine aquaculture, and similarly represents a threat to wild fish populations because of its high infectivity and broad host range. Betanodavirus, the causative agent of VER, is a small non-enveloped virus with a bipartite RNA genome comprising the RNA1 and RNA2 segments. We partially sequenced both RNA1 and RNA2 from 120 viral strains isolated from 2000 to 2009 in six different countries in Southern Europe. Phylogenetic analysis revealed the presence of the red-spotted grouper nervous necrosis virus (RGNNV) (n = 96) and striped jack nervous necrosis virus (SJNNV) (n = 1) genotypes in Southern Europe, with 23/120 samples classified as RGNNV/SJNNV reassortants. Viruses sampled from individual countries tended to cluster together suggesting a major geographic subdivision among betanodaviruses, although some phylogenetic evidence for viral gene flow was also obtained. Rates of nucleotide substitution were similar to those observed in a broad array of RNA viruses, and revealed a significantly higher evolutionary rate in the polymerase compared to the coat protein gene. This may reflect temperature adaptation of betanodaviruses, although a site-specific analysis of selection pressures identified relatively few selected sites in either gene. Overall, our analyses yielded novel data on the evolutionary dynamics and phylogeography of betanodaviruses and therein provides a more complete understanding of the distribution and evolution of different genotypes in Southern Europe.

Background Betanodaviruses are the causative agents of Viral Encephalopathy and Retinopathy (VER). To date, more than 50 species have proved to be susceptible and among them, those found in genus Epinephelus are highly represented. Clinical disease outbreaks are generally characterized by typical nervous signs and significant mortalities mainly associated with aquaculture activities, although some concerns for the impact of this infection in wild fish have been raised. In this study, the authors present the first documented report describing an outbreak of VER in wild species in the Mediterranean basin. Case presentation In late summer - early winter 2011 (September-December), significant mortalities affecting wild Dusky grouper (Epinephelus marginatus), Golden grouper (Epinephelus costae) and European sea bass (Dicentrarchus labrax) were reported in the municipality of Santa Maria di Leuca (Northern Ionian Sea, Italy). The affected fish showed an abnormal swimming behavior and swollen abdomens. During this epizootic, five moribund fish showing clear neurological signs were captured and underwent laboratory investigations. Analytical results confirmed the diagnosis of VER in all the specimens. Genetic characterization classified all betanodavirus isolates as belonging to the RGNNV genotype, revealing a close genetic relationship with viral sequences obtained from diseased farmed fish reared in the same area in previous years. Conclusion The close relationship of the viral sequences between the isolates collected in wild affected fish and those isolated during clinical disease outbreaks in farmed fish in the same area in previous years suggests a persistent circulation of betanodaviruses and transmission between wild and farmed stocks. Further investigations are necessary to assess the risk of viral transmission between wild and farmed fish populations, particularly in marine protected areas where endangered species are present.

This study investigated whether morphological parameters measured in eggs during early embryonic stages (first cleavage to morula) were useful for prediction of egg quality (% hatching embryos out of floating eggs) in Sparus aurata and Diplodus puntazzo. Eggs obtained from natural spawning were collected from commercial broodstocks. In the viable, floating eggs, the minimal and maximal diameter of the egg, yolk, and lipid vesicle were measured. Based on these measurements several parameters were calculated describing the shape of the egg, yolk, and lipid vesicle, and the size relationship between these compartments. These parameters were investigated for correlation with egg viability. From all investigated morphometric parameters only the ratio of the maximal to the minimal diameter of the lipid vesicle (RDLV) and the lipid vesicle shape coefficient (LVSC) were correlated with larval survival (%) from viable eggs. As the shape of a lipid droplet depends on the type and composition of lipid, the lipid to water ratio, and the interactions with the surrounding water molecules this parameter may be an index for the biochemical lipid composition.

The reproducibility of a recently developed method for egg quality determination in gilthead seabream ( Sparus aurata ) eggs was investigated with different broodstock fish and eggs from different stages of spawning time. The method uses activities of acid phosphatase, adenylate kinase, glucose-6-phosphatase, and transaldolase, and levels of amino acids, monosaccharides, and sialic acids as markers and multiple regression models to predict the egg quality. The method has general validity in the present study indicated by highly significant correlations obtained between calculated and experimentally obtained % prehatch survival. Moreover, highly significant correlations were found between predicted % prehatch survival and % posthatch survival. These methods were applied to Puntazzo puntazzo . The multiple regression models for egg quality determination in S. aurata were not useful in this species. However, multiple regression models adapted for P. puntazzo could predict the egg quality with a statistically high significance.

Eggs of the gilthead sea bream (Sparus aurata) obtained from natural spawning were collected from commercial broodstocks. In the viable, floating eggs selected biochemical parameters were measured and embryo survival to hatch was determined. Then biochemical parameter correlations with embryo survival to hatch were made to determine potential biochemical egg quality markers. From the investigated parameters (acid phosphatase, adenylate kinase, alanine aminotransferase, malate dehydrogenase, glucose-6-phosphatase, succinate dehydrogenase, transaldolase, acetyl CoA, amino acids, ATP, DNA, fructose, glucose, glucose-6-phosphate, NADH, NAD, phosphate, phospholipid, monosaccharides, sialic acid) only the following were correlated with embryo survival to hatch: adenylate kinase, glucose-6-phosphatase, transaldolase, amino acids, sialic acid, glucose-6-phosphate, acid phosphatase and free monosaccharides. For all listed parameters the explanatory effect in simple regression models was low as R2 was

The present study investigated selected biochemical parameters in viable and nonviable eggs of the gilthead sea bream, Sparus aurata . During embryogenesis, S. aurata eggs had a balanced and stable energy metabolism as the levels of adenosine nucleotides and acetyl-CoA, and the adenylate energy charge (EC), remained constant. Mg 2+ -dependent ATPase, which is involved in membrane-driven ion transport during oxidative phosphorylation, increased in activity. In nonviable eggs, the levels of ATP, acetyl-CoA, the adenylate energy charge, and the activities of malate dehydrogenase were significantly decreased in comparison to viable eggs. Viable eggs had high Na + /K + -ATPase activity which remained constant during embryogenesis while Ca 2+ -ATPase activity increased. These enzymes were similarly high in nonviable eggs indicating that the ability for ion transport and for osmoregulation did not differ. However, nonviable eggs contained nonphysiological high levels of magnesium and calcium ions indicating ion influx from the seawater. As the phospholipid levels were significantly lower in nonviable eggs, this ion influx is thought to be related to changed composition of the oolemma. Activities of glucose-6-phosphate dehydrogenase, transaldolase, phosphofructokinase, and pyruvate kinase were constant in viable eggs of S. aurata during embryogenesis. Pyruvate carboxylase increased in activity in the embryonic stage. The occurrence of these enzymes indicated the presence of the enzymatic system for glycolysis for gluconeogenesis and for the pentose phosphate pathway. The monosaccharide levels (i.e. total amount, glucose, fructose, galactose) increased steadily during egg development. Monosaccharides are necessary for nucleic acid synthesis levels, which increased during embryogenesis, and may also play a role as osmotically active compounds. In nonviable eggs, levels of all assayed sugars as well as activities of pyruvate carboxylase and transaldolase were very significantly decreased. Enzymes involved in the catabolism of proteins and amino acids (proteases, aspartate aminotransferase, glutamate dehydrogenase) were constant in the viable eggs with the exception of aspartate aminotransferase, which increased significantly in the embryonic stage. Nonviable eggs had lower activities of glutamate dehydrogenase than viable eggs, while the other enzyme activities were similar. Amino acid levels and inorganic phosphate levels were lower in nonviable than in viable eggs.

Betanodaviruses are the causal agents of viral encephalo-retinopathy, an infectious disease affecting more than 40 marine fish species, characterized by high morbidity and mortality. Because of its severe impact, robust diagnostic tools are required. The aim of this work was to develop and validate a real-time TaqMan PCR assay to detect betanodaviruses in clinical specimens by amplifying a conserved region of the RNA2 strand. The method proved to be specific and sensitive, being capable of detecting as low as 10 TCID(50)/ml. For clinical validation, samples from 100 marine fish were collected during a natural outbreak of disease and tested by three distinct laboratory methods, namely real-time TaqMan PCR, RT-seminested PCR and virus isolation. The results indicated optimal agreement between tests. The assay that was developed is capable of detecting members of all of the betanodavirus genetic groups currently described and can be considered a valid alternative to the time-consuming and contamination-prone nested PCR.