Chromosome analysis using different staining techniques and fluorescent in situ hybridization in Cerithium vulgatum (Gastropoda: Cerithiidae)

In the present paper one population of the "large" subtidal mollusc Cerithium vulgatum Bruguiere, 1792 (Gastropoda: Cerithiidae) from the Northwestern coast of Sicily was investigated from a karyological point of view. The chromosome complement was Giemsa stained, conventionally karyotyped in 18 homomorphic chromosome pairs (10 bi-armed and 8 mono-armed), and subsequently analysed using silver, CMA3 and DAPI staining, and fluorescent in situ hybridization (FISH) with three repetitive DNA probes [ribosomal DNA (rDNA), (TTAGGG)n and (GATA)n]. FISH with the rDNA probe consistently mapped major ribosomal sites (18S-28S rDNA) in the terminal region of the short arms of one small sized mono-armed chromosome pair. Ribosomal DNA was transciptionally active as indicated by its preferential impregnation with silver nitrate (Ag-NOR) and did not contain a high amount of GC base pairs as suggested by the lack of a bright CMA3 fluorescence. The (TTAGGG)n telomeric probe was hybridized to the termini of nearly all chromosomes, thus demonstrating that, in C. vulgatum, this sequence has been conserved during the genomic evolution. The finding of the telomeric hexanucleotide in six species belonging to the three high taxa of Gastropoda supports the notion that this sequence is widespread within this class. The (GATA)n probe did not label any chromosome regions except for a minute terminal area of a single bivalent at pachytene stage

Fish community in a surf zone of the northern Sicilian coast (Mediterranean Sea): diversity and functional guild composition

Fish assemblage in a surf zone of the southern Tyrrhenian Sea was investigated for the first time. Samples were collected during four surveys by a modified beach-seine, from June 2005 to May 2006. Overall, 42 species belonging to 19 families were recorded. Among them, Sardina pilchardus showed the highest abundance values, while Mugilids (Oedalechilus labeo and Liza aurata) were the most frequently caught species. The fish community was dominated by pelagic and gregarious species using this habitat as a foraging ground and recruitment area. Juveniles and early adults made up the largest proportion of the ichthyofauna. Fishes inhabiting the surf zone were mainly strictly benthic invertebrate feeders and invertivorous/piscivorous fish; strictly planktivorous were represented by few species but strongly dominant in terms of catch per unit effort; strictly piscivorous fish were poorly represented. Fish composition varied over the study period with the greatest abundance in May and December, and the highest richness and diversity in October

Preliminary observations of caulerpin accumulation from the invasive Caulerpa cylindracea in native Mediterranean fish species

Recent studies have shown that the Mediterranean white sea bream Diplodus sargus includes the invasive green alga Caulerpa cylindracea in its diet, with consequent metabolic and enzymatic alterations. As a result of this novel alimentary habit, the bioactive algal red pigment caulerpin has been detected in its tissues. However, this may not be an isolated case: other fish species have also been reported to feed on C. cylindracea, although the possible accumulation of caulerpin in their tissues has not yet been investigated. In this report, we analysed stomach contents and caulerpin levels in the native sparid species Spondyliosoma cantharus, Sarpa salpa, and Diplodus vulgaris, and in the scarid Sparisoma cretense, along with the Lessepsian siganid Siganus luridus. C. cylindracea was found in the stomachs of all but one fish species, the exception being S. cretense, in which prey items could not be determined due to the high degree of digestion. Chemical analysis of fish tissues revealed that only S. cantharus and S. salpa accumulated caulerpin, while no traces of the compound were detected in the other species. Despite intense research efforts on natural products obtained from C. cylindracea, a complete picture of the impacts caused by fish including this alga in their diet has not been elucidated. The identification of caulerpin in other Mediterranean native fish suggests a need for further research in order to assess the possible transfer of such molecules to humans through seafood consumption

Sneaking into a Hotspot of Biodiversity: Coverage and Integrity of a Rhodolith Bed in the Strait of Sicily (Central Mediterranean Sea)

Habitat mapping, physical characteristics and benthic community of a rhodolith bed in the Pelagie Islands (Strait of Sicily, Mediterranean Sea) were studied through Multi–Beam Echo–Sounder (MBES), Remotely Operated Vehicle (ROV) and grab samples. The geomorphological analysis revealed an articulated and wide rhodolith bed; video inspections highlighted a bed with high coverage, few sandy patches and with a prevalence of the boxwork morphotype. A total of 207 taxa with 876 specimens were identified, and Polychaeta was the dominant taxon. Linguimaera caesaris, a Lessepsian benthic amphipod, was recorded in all sampling sites, and its presence represents an input to deepen the benthic assemblage research on the rhodolith bed. In terms of morphotype composition, dead/live ratio and species variability, the bed variability indicated a good status of health, although trawling signs were detected through ROV videos. The present study broadens the knowledge on Mediterranean rhodolith beds and supports the importance of survey and monitoring activities for the conservation and management of this important habitat

Bathymetric and longitudinal distribution analyysis of the rockfish Helicolenus Dactylopterus (Delaroche, 1809) in the southern Tyrrhenian Sea (central Mediterranean)

This study provides information on bathymetric and longitudinal distribution heterogeneity of the rockfish Helicolenus dactylopterus in the southern Tyrrhenian Sea. Data were drawn from experimental bottom trawl (1996-2002) plus bottom trap (2001-02) surveys. The frequency of occurrence and mean relative density (N/km2) and biomass (kg/km2) indexes were calculated for two survey seasons (spring and autumn), four geographic sectors and three depth strata. MANOVA was used to test fish abundance among years, sectors and strata. Analysis of the length-frequency distributions was carried out by two-way (gears and depths) ANOVA, post hoc multiple comparisons for testing differences among depths and Student’s t test for testing differences between gears. Length-weight relationship was also estimated and the allometric coefficient was tested with the Student’s t test. The results showed a significant positive bathymetric gradient of sizes both for trawl and trap surveys; at same depths, fish caught by traps were significantly longer than those caught by trawl. In spring surveys, significant differences were found among strata for both abundance indexes; in autumn surveys, significant differences between depth strata were found only for density indices. The distribution and abundance patterns of H. dactylopterus along the southern Tyrrhenian Sea was homogeneous among sectors. Length-weight relationship showed a significant positive allometric growth

Comparison between intermediate and severe coronary stenoses and clinical outcomes of an OCT-guided PCI strategy

We compared optical coherence tomography (OCT) features of intermediate and severe coronary stenoses in patients with stable angina and acute coronary syndrome (ACS), and tested the clinical impact of an OCT-based strategy for treating intermediate stenoses

Reproductive cycle and gonadal output of the Lessepsian jellyfish Cassiopea andromeda in NW Sicily (Central Mediterranean Sea)

Knowledge of the reproductive strategy is a key prerequisite to predict population dynamics and potential invasiveness of both native and non-indigenous outbreak-forming species. In 2014 the Lessepsian upside-down jellyfish Cassiopea andromeda reached the harbor of Palermo (NW Sicily, Thyrrenian Sea), to date its established westernmost outpost in the Mediterranean Sea. To predict C. andromeda reproductive success in its novel habitat, gonad histology was carried out to record the number and size of mature and immature oocytes. Both male and female simultaneously presented gametes at all stages of development suggesting an asynchronous, yet apparently continuous, reproduction strategy. Indeed, oogenesis was observed throughout the year from pre-vitellogenic, vitellogenetic, and late-vitellogenetic to mature oocytes suggesting multiple reproductive events, as known in other Mediterranean Rhizostomeae. Oocytes were found from May to December, with two seasonal peaks of abundance (late spring = 392 and autumn = 272), suggesting imminent spawning events. Further, jellyfish size varied significantly throughout the year, with maximum diameter (up to 24 cm) in summer, and minimum diameter (6 cm) in winter. Small-sized jellyfish in winter belong to the new cohort, most probably arising from intense summer strobilation of polyps. Late spring fertilization, planula development, and metamorphosis, followed by polyp strobilation in the summer months, may explain the late appearance of a new jellyfish cohort, likely coincident with that recorded throughout winter