1,721,001 research outputs found
Parasites of cage cultured European seabassDicentrarchus Labraxand gilthead seabreamSparus auratafrom Sardinia (western Mediterranean): first results
Full text linkEuropean seabassDicentrarchus labraxand gilthead seabreamSparus aurataare the most important marine finfish species intensively cultured in the Mediterranean. Many factors influenced the rapid increase in the production
of these species in the last two decades. One of the most important factors is the great development and diffusion
of sea-cage culture, because some of the parasite species has become a serious threat to cage-reared fish in other Mediterranean localities
Immune cells in the spiral intestine of Blackmouth catshark, Galeus melastomus: New insights into ancient gut defenders
No full textThis study aimed to describe the morphology and to characterize the immunohistochemistry of the gut-associated lymphoid tissue (GALT) in the spiral intestine of the Blackmouth catshark Galeus melastomus. In the catshark, the lympho-myeloid aggregate of the GALT was mainly confined to the central region of the spiral valve. A panel of eight immune molecular markers was applied to histological sections to show the cell types of the GALT using immunohistochemical and -fluorescence methods. Two main reactive cell types were identified: (i) a mast cell lineage positive to histamine, serotonin, and immunoglobulin E-like receptor antibodies, and (ii) a macrophage lineage positive to CD4, interleukin-6, lysozyme, toll-like receptor-2, and tumor necrosis factor-α antibodies. Confocal microscopy revealed which immune markers were co-localized in the same cell type. The presence of cells positive to the tested antibodies confirmed the defensive role against pathogens of the GALT in the spiral intestine of the catshark. Given the limited knowledge of the elasmobranch immune system, the current study provides new insights into the features of ancient defender cells of the spiral intestine
The Leydig organ of elasmobranchs: Shed light on an active and mysterious defense center with immunological characterization of its cells
No full textIn elasmobranchs, blood cells originate from the thymus, spleen, and two organs associated with the gonads and esophagus: the epigonal and Leydig organs (LO), respectively. In the LO parenchyma, various granulocyte types, thrombocytes, and lymphocytes were observed, with notable species-specific diversity. Cells of the LO in the catshark Galeus melastomus were characterized using immunohistochemistry, immunofluorescence, and electron microscopy. Image analysis of sections treated with the anti-proliferative cell nuclear antigen antibody revealed that approximately 40 % of LO cells were in mitosis and approximately 15 % were myeloid progenitors positive for the anti-c-kit antibody. Additionally, a panel of 12 immunological markers revealed that 18.4 %, 17.8 %, 13.7 %, and 14.1 % of the LO section area was occupied by cells positive for anti-serotonin, interleukin-6, histamine, and immunoglobulin E-like receptor antibodies, respectively. Two main reactive cell types, mast cell and macrophage lineage, were revealed by co-localization image analysis using confocal microscopy. Ultrastructural observation identified granulocytes and macrophages as the main cell types. To our knowledge, this is the first report on the distinct patterns of LO cell populations and their morphological features, confirming granulopoietic role of the elasmobranch LO
North-easternmost record of <i>Halosaurus ovenii</i> Actinopterygii: Notacanthiformes: Halosauridae) in the Mediterranean Sea, with notes on its biology
Full text linkA single adult female specimen of Halosaurus ovenii Johnson, 1864 was captured by trammel nets at a depth of about 200 m off the coast of Arbatax (Sardinia, Italy) in early April 2007. Macroscopic and microscopic analysis of the gonad showed a postspawning ovary. This is the fourth documented capture of this fish in the Mediterranean Sea, representing the north-easternmost record for this species in this geographic area. Furthermore, the present specimen was fished at the shallowest depth ever recorded before
Occurrence ofPhilometra lateolabracis(Nematoda: Philometridae) in the gonads of marine perciform fishes in the Mediterranean region
Full text linkGravid females of the nematodePhilometra lateolabracis(Yamaguti, 1935), a parasite of gonads of marine perciform fishes, were found in wild and cultured dusky grouperEpinephelus marginatus(Lowe) from waters near the Balear Islands (Spain, Mediterranean Sea) and Sicily (Italy, Thyrrenean Sea), and in the greater amberjackSeriola dumerili(Risso) in Croatia (south-eastern Adriatic Sea). In wildE. marginatusin Spain, the overall prevalence was 21% and the intensity of infection 1 nematode per fish. The nematodes are briefly described and illustrated. The speciesSanguinofilaria jordanoiLópez-Neyra, 1951, described from the ovary ofEpinephelus gigasBrünich from Morocco, is synonymized with P. lateolabracis. This is the first documented record ofP. lateolabracisfrom fishes of the Mediterranean region and its finding inS. dumerilirepresents a new host record. The possible importance of this pathogenic parasite for cultures of marine perciform fishes in the region is stressed
New data on Gaidropsarus granti (Regan, 1903) (Gadiformes: Lotidae) from the Mediterranean Sea, with emphasis on its parasites
Full text linkOne adult male Azores rocklingGaidropsarus grantiwas captured by trammel nets at a depth of about 250 m near the coast of Arbatax (Sardinia, Italy) in early March 2007. This new report confirms a wide bathymetric range for this species. Macroscopic and microscopic analysis of the gonad showed a spent testis at a postspawning stage, with a weak residual spermatogenetic activity. Several body parts of Natantia (Crustacea: Decapoda) were detected in its stomach contents. Different developmental stages of 91 parasite specimens belonging to Arthropoda (Gnathiidae) and Nematoda (Anisakidae, Cystidicolidae and Philometridae) were found in its mouth and gills, and body cavity, respectively. Myxozoan spores were found in the gallbladder. Male and female nematodes of the genusIchthyofilariaare reported for the first time from the Mediterranean Sea, and a very rare male of this genus is reported for the second time in the world. Parasitological results indicated that this Atlantic migrant probably entered the Mediterranean as an adult, suggesting for a non-indigenous species the possibilities of entering with natural parasites and/or acquiring native parasites in the introduced range
New insights into the coexistence of Contracaecum rudolphii A and Contracaecum rudolphii B (Nematoda: Anisakidae) in Phalacrocorax carbo sinensis from Sardinia: genetic variability and phylogenetic analysis
No full textContracaecum sp. nematodes are important parasites of fish eating birds that can cause animal health problems. In the present study, specimens of Contracaecum rudolphii sensu lato, from the great cormorant Phalacrocorax carbo sinensis from Sardinia, were characterized based on morphological and molecular data. The morphological analysis allowed to identify all the fourth stage larvae (n = 1918) as Contracaecum sp., and adults, male (n = 5845) and female (n = 8312), as C. rudolphii sensu lato. Population genetics and phylogenetic relationships were inferred based on mitochondrial and nuclear markers. Multiple sequence alignment of the ribosomal internal transcribed spacer showed the coexistence of C. rudolphii A (n = 157), C. rudolphii B (n = 22) and a rare heterozygote of these species. Moreover, mitochondrial markers, namely NADH dehydrogenase subunits I (nad1), cytochrome c oxidase subunit (cox1 and cox2) and small subunit of rRNA (rrnS), showed that the studied C. rudolphii A populations had undergone bottleneck, or founder effect event, subsequent to a rapid population growth and expansion. The observed heterozygote is with a mitochondrial pattern of C. rudolphii B. Although, both Contracaecum species showed high genetic diversity, no genetic structure between localities was detected. Phylogenetic reconstructions supported the paraphyly of the avian Contracaecum species including C. ogmorhini (parasite of otariids)
Xenoligophoroides cobitis (Ergens, 1963) n. g., n. comb. (Monogenea: Ancyrocephalidae), a parasite of Gobius cobitis Pallas (Perciformes: Gobiidae) from the Mediterranean and Black seas
No full textBased on an integrative taxonomic approach, combining morphological characters and partial sequences of the nuclear 28S rRNA gene, a new genus and combination for the species Xenoligophoroides cobitis (Ergens, 1963) is proposed, to accommodate ancyrocephalid monogeneans, parasites on the gills of Gobius cobitis Pallas (Gobiidae) from the western Mediterranean Sea and the northern Black Sea. A morphological comparison of newly collected material with the descriptions of Ancyrocephalus cobitis Ergens, 1963 and Haliotrema cupensis Sasal, Pages & Euzet, 1998, recently synonymised and named as Haliotrema cobitis (Ergens, 1963), confirms their similarity and belonging to the same species. However, characters of this species, as the vas deferens not looping the caecal branch, the bilobed base of the male copulatory organ and the marginal hooks with an upright thumb, do not correspond to the diagnosis of Haliotrema Johnston & Tiegs, 1922. Morphologically, this species is close to members of Ligophorus Euzet & Suriano, 1977 and Kriboetrema Sarabeev, Rubtsova, Yang & Balbuena, 2013, but differs from the former in the accessory piece articulated with MCO and two prostatic reservoirs, and from the latter in the uncoiled MCO with bilobed base and the dextral vaginal pore. Moreover, all species of Ligophorus and Kriboetrema are parasites of grey mullets. A 28S rDNA-based phylogenetic analysis of sequences derived from specimens of X. cobitis from the Mediterranean and Black seas, along with sequences from several closely related genera of the Ancyrocephalidae, suggested the occurrence of a new taxonomic unit, which corresponded to the X. cobitis specimens. This finding supports the establishment of the new genus for the ancyrocephalid parasites on the gills of G. cobitis from the western Mediterranean Sea and the northern Black Sea
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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