713 research outputs found
Athos. Formes dans un lieu sacré. Sélection de textes, notes et photographies par Paul M. Mylonas
No full textAthos. Formes dans un lieu sacré. Sélection de textes, notes et photographies par Paul M. Mylonas. In: Revue des études byzantines, tome 33, 1975. p. 338
Athos. Formes dans un lieu sacré. Sélection de textes, notes et photographies par Paul M. Mylonas
No full textAthos. Formes dans un lieu sacré. Sélection de textes, notes et photographies par Paul M. Mylonas. In: Revue des études byzantines, tome 33, 1975. p. 338
Metafruticicola kavafis Bitzilekis & Vardinoyannis & Mylonas 2023, sp. nov.
No full text<i>Metafruticicola kavafis</i> sp. nov. <p>urn:lsid:zoobank.org:act: 3A8F3EC3-0B6F-4095-B03A-406E8191FE83</p> <p>Figs 1, 3</p> Diagnosis <p> A rather small species of <i>Metafruticicola</i> with a globular shell and a narrow umbilicus that may be covered to a small degree by the converging peristome. Shell light brownish with a whitish band on the periphery. Protoconch with regularly spaced axial ribs (Fig. 1A). Penis papilla is very long, curved at the tip and “tongue-shaped”.</p> Etymology <p> Named in honor of Konstantinos Kavafis (Constantine P. Cavafy), one of the greatest Greek poets, who lived in late 19 th to early 20 th century. His most renowned poem is Ithaca.</p> Material examined <p> <b>Holotype</b> GREECE • 1 spec. in 75% alcohol and dissection (dimensions: H 8.69 mm, D 11.85 mm, W 52/s); Dodecanese, Kasos Island, Alonaki above Poli; 35.4031° N, 26.9415° E; 25 Nov. 1988; M. Mylonas leg.; NHMC 50.8135.</p> <p> <b>Paratypes</b> GREECE • 6 shells, 7 specs in 75% alcohol, 6 dissections; same collection data as for holotype; NHMC 50.51421.</p> <p> <b>Other material</b> GREECE • 29 shells, 2 specs in 75% alcohol, 1 dissection; same collection data as for holotype; 22 Mar. 2018; E. Bitzilekis leg.; NHMC 50.47114 • 2 shells; Dodecanese, Kasos Island, Prionas Mt; 35.4107° N, 26.9764° E; 15 Feb. 1992; K. Vardinoyannis leg; NHMC 50.5650.</p> Locus typicus <p>Greece, Dodecanese, Kasos Island, Alonaki east of Poli.</p> <p> <b>Description</b> (Fig. 1A)</p> <p>SHELL. Pale brownish with one whitish band on the periphery and one prominent growth interruption. Upper insertion of the aperture is slightly descending. Peristome is slightly reflected with a pale yellowish internal thickening. It bears a narrow umbilicus, which is not or hardly covered by the reflected peristomial edge. Upper and lower insertion of the peristome are hardly converging and are either not connected or connected by a weakly developed callus. Whorls 51/s–56/8. The microsculpture of the protoconch carries regular, narrowly spaced, axial ribs that in some animals seem to transform to elongated pustulation. Teleoconch shiny, with radial growth ridges and without hairs or hair scars.</p> <p>SHELL DIMENSIONS (n = 37). H 7.39–10.13 mm (mean = 8.71 mm); D 10.41–13.11 mm (mean = 11.81 mm); W 5 1/s–56/8 (mean = 54/s). All shells with one growth interruption.</p> <p>GENITALIA (Fig. 1B–D). Flagellum long, one and a half times the length of epiphallus. Epiphallus evenly thick. Penial retractor is attached in the middle or upper third of the epiphallus. Penis bulky, thicker and quite distinct in its junction with epiphallus and half the size of the latter. At the junction with the epiphallus a prominent bump is formed. Inside the penis there is a very long tongue-like papilla with many irregular furrows, which folds like a scoop at the edge. Epiphallic pore opens on the top of the longitudinal slit, which runs throughout the whole length of the back of the “tongue”. Inner penial walls are smooth (Fig. 1C). Vas deferens slender. Vagina one third of penis’ length and half its width. The base of the duct of the gametolytic gland is thick-walled and as broad as the penis. Inside the thickened base of this duct there are slender longitudinal ridges (Fig. 1D). Free oviduct slender and at its junction to the duct of the gametolytic gland a bump is formed. Gametolytic gland is oval.</p> Distribution <p>Currently, it is only known from the eastern part of Kasos Island, east of the small village of Poli and eastwards till the mountain Prionas, which is the highest peak of the island.</p> Remarks <p> <i>Metafruticicola kavafis</i> sp. nov. can be distinguished from <i>M. n. conciliatrix</i> by its generally smaller shell. However, small specimens of <i>M. n. conciliatrix</i> are generally darker and less globular than <i>M. kavafis</i>. The penial papilla of <i>M. kavafis</i> is unique and can hardly be confused with that of any other congeneric species. It lives exclusively in phryganic ecosystems and abandoned cultivations. The species is not common in the area where it was found. Both living specimens and empty shells were found almost exclusively in close affiliation to the shrub <i>Lithodora hispidula</i> (Sm.) Griseb. In late March, juveniles and semi-adults were still active either in the litter or on <i>Lithodora hispidula</i>, whereas all living adults and some semi-adults that were found had already sealed their aperture with an epiphragm and were aestivating, facing upwards, deep in the litter under the plants. There were no signs of the animals under rock boulders or other phryganic plants like <i>Thymbra capitata</i> (L.) Cav. or <i>Sarcopoterium spinosum</i> (L.) Spach. <i>Metafruticicola kavafis</i> lives sympatrically with <i>M. pellita</i>. However, the latter species was found in many habitats, even under <i>Lithodora hispidula</i>, though it showed a clear preference for shelters under piles of rocks, where it could be found in very dense populations.</p>Published as part of <i>Bitzilekis, Eleftherios, Vardinoyannis, Katerina & Mylonas, Moisis, 2023, A new species of Metafruticicola (Gastropoda, Hygromiidae) from the Aegean Archipelago and new anatomical and distributional data on some congeneric species, pp. 1-23 in European Journal of Taxonomy 879 (1)</i> on pages 3-6, DOI: 10.5852/ejt.2023.879.2155, <a href="http://zenodo.org/record/8135424">http://zenodo.org/record/8135424</a>
OOGENESIS IN WILD AND REARED GREATER AMBERJACK SERIOLA DUMERILI (RISSO, 1810)
No full textIntroduction
The incorporation of new species in the aquaculture industry necessitates to control the reproductive function in captivity and to produce high numbers of high-quality eggs. Greater amberjack Seriola dumerili (Risso, 1810) caught from the wild and reared in captivity have been shown not to develop further than early vitellogenesis or if they did complete vitellogenesis, they failed to undergo oocyte maturation and required exogenous hormonal therapies to induce ovulation and spawning (Mylonas et al., 2004).The present work represents an overview of the results obtained in a study on the oogenesis of wild and captive-reared greater amberjack carried out within the EU FP7 project Diversify (Zupa et al, 2017; Pousis et al., 2018, 2019).
Material and Methods
Twenty-one wild and twelve captive-reared greater amberjack females were sampled during 2014, 2015 and 2016 at three different phases of the reproductive cycle: early gametogenesis (EARLY), late April-early May (wild fish = 5; captive-reared fish = 4); advanced gametogenesis (ADVANCED), late May-early June (wild fish = 4; captive-reared fish = 4); spawning (SPAWNING), late June-early July (wild fish = 12; captive-reared fish = 4). Wild fish were sampled on board a professional purse-seine fishing vessel operating around the Pelagie Islands (Sicily, Italy); captive-reared individuals belonged to a broodstock captured as juveniles and moved to a sea cage of Argosaronikos Fishfarming S.A. (Salamina Island, Greece). For each fish, biometric data (fork length, FL, in cm; body mass, BM, in kg; testis mass, TM, in g) were registered and gonadosomatic index (GSI = 100 × TM/BM) was calculated. Liver samples were store at -80°C and subsequently used for the analysis of vitellogenin (vtga, vtgb and vtgc) expression through RT-PCR. Ovary samples were used for histological analysis and for vitellogenin receptor (vtgr and lrp13) expression analysis through RT-PCR. Blood samples were centrifuged and plasma was stored at -20°C for the analysis of testosterone, 17β-estradiol and 17,20β-dihydroxypren-4-en-3-one by ELISA assays.
Results and Discussion
The GSI and all the sex steroid plasma levels were lower in captive-reared fish. During the EARLY phase, wild and captive-reared fish displayed perinucleolar or early vitellogenesis as the most advanced oocyte stage. During the ADVANCED phase, when the wild greater amberjack breeders were already in spawning condition (Fig. 1a), ovaries of captive-reared breeders showed extensive atresia of late vitellogenic oocytes (Fig. 1b). During the SPAWNING period, all captive-reared fish had regressed ovaries, while wild breeders still displayed oocytes at late vitellogenesis and maturation stages as well as postovulatory follicles.
The expression levels of vtga, vtgb and vtgc did not differ significantly between captive-reared and wild females. Ovarian vtgr and lrp13 transcription was more active during early gametogenesis, suggesting that vitellogenin receptor transcripts were synthesized by previtellogenic oocytes and remained in the cellular mRNA pool until oocytes resumed meiosis and entered vitellogenesis. A reduced vtgr and lrp13 transcription was observed in captive-reared compared wild greater amberjack during the EARLY phase. The observed reproductive dysfunction, leading to oocyte atresia and reduced gonadosomatic index, arose during the early phase of oogenesis, when transcription of vitellogenin receptor genes appeared to be reduced, and did not appear to be associated to a lower liver capacity to synthesize the egg yolk precursors. Severe reproductive dysfunctions were observed also in males of the same broodstock and involved low sex steroid plasma concentrations and precocious cessation of spermatogenesis (Zupa et al., 2017). Preliminary data obtained within the H2020 project NewTechAqua indicate that hatchery-produced greater amberjack reared in sea cages in Salamina (Greece) have similar GSI compared with wild fish sampled in the same period of the reproductive cycle (early June 2021). Although further analyses are required, the available data indicate that hatchery-produced individuals might be less affected by captivity-induced stress than wild-caught breeders.
Financial grant provided by the European Union ́s Programmes FP7 (GA 603121, DIVERSIFY) and H2020 (GA 862658, NewTechAqua).
References
Mylonas, C.C., Papandroulakis, N., Smboukis, A., Papadaki, M., Divanach, P. 2004. Induction of spawning of cultured greater amberjack (Seriola dumerili) using GnRHa implants. Aquaculture, 237: 141-154.
Pousis, C., Mylonas, C. C., De Virgilio, C., Gadaleta, G., Santamaria, N., Passantino, L., Zupa, R., Papadaki, M., Fakriadis, I., Ferreri, R., Corriero A. 2018. The observed oogenesis impairment in greater amberjack Seriola dumerili (Risso, 1810) reared in captivity is not related to an insufficient liver transcription or oocyte uptake of vitellogenin. Aquaculture Research, 49: 243-252.
Pousis, C., Rodríguez, C., De Ruvo, P., De Virgilio, C., Pérez, J.A., Mylonas, C. C., Zupa, R., Passantino, L., Santamaria, N., Valentini, L., Corriero A. 2019. Vitellogenin receptor and fatty acid profiles of individual lipid 1 classes of oocytes from wild and captive-reared greater amberjack (Seriola dumerili) during the reproductive cycle. Theriogenology, 140: 73-83.
Zupa, R., Rodríguez, C., Mylonas, C. C., Rosenfeld, H., Fakriadis, I., Papadaki, M., Pérez, J. A., Pousis, C., Basilone, G., Corriero, A. 2017a. Comparative study of reproductive development in wild and captive-reared greater amberjack Seriola dumerili (Risso,1810). PLoS ONE 12(1): e0169645
Numerical study of asymmetric keel hydrodynamic performance through advanced CFD
No full textThe hydrodynamics of an asymmetric IACC yacht keel at angle of yaw are presented using simulations performed by advanced computational fluid dynamics using state-of-the-art software. The aim of the paper is to continue working on the improvement of numerical viscous flow predictions for high-performance yachts using Large Eddy Simulation and Detached Eddy Simulation on unstructured grids. Quantitative comparisons of global forces acting on the keel and wake survey are carried out. Qualitative comparisons include flow visualisation, unsteady and separated flow and other features. Star-CCM+ and the trimmed cell method give better forces and wake prediction compared to the unstructured mesh of ANSYS Fluent. Both solvers give good flow visualisation near and far field of the keel
Fig. 3 in A new species of Metafruticicola (Gastropoda, Hygromiidae) from the Aegean Archipelago and new anatomical and distributional data on some congeneric species
No full textFig. 3. Distribution of Metafruticicola (Rothifruticicola) kavafis sp. nov. (▲) and M. (R.) nicosiana conciliatrix Fuchs & Käufel, 1936 (●). New records of M. n. conciliatrix from Saria Island (●).Published as part of Bitzilekis, Eleftherios, Vardinoyannis, Katerina & Mylonas, Moisis, 2023, A new species of Metafruticicola (Gastropoda, Hygromiidae) from the Aegean Archipelago and new anatomical and distributional data on some congeneric species, pp. 1-23 in European Journal of Taxonomy 879 (1) on page 10, DOI: 10.5852/ejt.2023.879.2155, http://zenodo.org/record/813542
Mylonas (George E.). Excavations at Olynthus Part. I. The neolithic Settlement. Robinson (David M.). Excavations at Olynthus Part. II. Architecture and Sculpture : Houses and other Buildings
No full textGraindor Paul. Mylonas (George E.). Excavations at Olynthus Part. I. The neolithic Settlement. Robinson (David M.). Excavations at Olynthus Part. II. Architecture and Sculpture : Houses and other Buildings. In: Revue belge de philologie et d'histoire, tome 10, fasc. 3, 1931. pp. 659-665
SPERMATOGENESIS IN WILD AND CAPTIVE-REARED GREATER AMBERJACK Seriola dumerili (RISSO, 1810)
No full textIntroduction
Greater amberjack Seriola dumerili (Risso, 1810) is an excellent candidate for aquaculture thanks to its rapid growth,
excellent flesh quality and worldwide market appreciation. As other captive-reared fishes exhibiting reproductive
dysfunctions (Zohar and Mylonas, 2001), greater amberjack males produced reduced sperm volume with a decreased
sperm quality. The present work represents an overview of the results obtained in a comparative research study on the
spermatogenesis of wild and captive-reared greater amberjack carried out in the framework of the EU FP7 project Diversify (www.diversifyfish.eu) (Zupa et al, 2017a, b).
Material and Methods
Twelve greater amberjack males caught from the wild and reared in captivity for three years in a sea cage in Salamina
Island (Greece) and 14 males caught from the wild around Pelagie Islands (Sicily, Italy), were sampled during three phases of the reproductive cycle: early spermatogenesis (late April-early May), advanced spermatogenesis (late May-early June) and spawning (late June-July). For each fish, biometric data (fork length, FL, in cm; body mass, BM, in kg; testis mass,
TM, in g) were registered and gonadosomatic index (GSI = 100 × TM/BM) calculated. Testis samples were chemically
fixed and destined to basic histological analysis and to the identification of proliferating and apoptotic germ cells through the immunohistochemical detection of the proliferating cell nuclear antigen (PCNA) and the TUNEL method, respectively. Blood samples were centrifuged and plasma was collected and stored at -20°C for the analysis of 17β-estradiol (E2), testosterone (T), 11-ketotestosterone (11-KT) and 17,20β-dihydroxypren-4-en-3-one (17,20β-P) by ELISA assays.
Results and Discussion
Captive-reared fish showed lower GSI and smaller seminiferous lobules compared to wild fish in all the three phases of the reproductive cycle.
Anti-PCNA immunostaining was observed in the nuclei of spermatogonia and primary spermatocytes (Fig. 1a). All the
captive-reared and most of the wild greater amberjack showed TUNEL-positive germ cells (Fig. 1b). Individuals reared
in captivity showed a gradual decrease of germ cell proliferation throughout the three reproductive phases, which led to a precocious cessation of the spermatogenesis as well as a higher germ cell apoptosis in early spermatogenesis. In all three reproductive phases, captive-reared fish showed lower T, 11-KT and 17,20β-P plasma concentrations compared to wild
fish; however, captive-reared fish showed a many-fold higher E2 plasma levels during the early spermatogenesis.
The occurrence of a severe endocrine dysfunction was described in captive-reared greater amberjack males, including
low T, 11-KT and 17,20β-P plasma levels during all the examined spermatogenesis phases. Abnormally high E2 plasma
concentrations were associated to an increased germ cell apoptosis during early spermatogenesis. The observed reproductive dysfunction finally led to a lower sperm concentration and quality (Zupa et al., 2017a). A severe impairment of the reproductive function was observed also in females of the same broodstock and involved low steroid plasma concentrations and extensive atresia of late vitellogenic oocytes (Zupa et al., 2017b). Preliminary data obtained within the H2020 project NewTechAqua indicate that hatchery-produced greater amberjack males reared in sea cages in Salamina (Greece) have similar GSI compared with wild fish sampled in the same period of the reproductive cycle (early June 2021). Although further analyses are required, the available data seem to suggest that the reproductive function might be less affected by captivity-induced stress in hatchery-produced greater amberjack than in wild-caught breeders.
Financial grant provided by the European Union ́s Programmes FP7 (GA 603121, DIVERSIFY) and H2020 (GA 862658,
NewTechAqua)
References
Zohar, Y., Mylonas, C. C. 2001. Endocrine manipulations of spawning in cultured fish: from hormones to genes. Aquaculture,
197: 99–136.
Zupa, R., Fauvel, C., Mylonas, C. C., Pousis, C., Santamaria, N., Papadaki, Μ., Fakriadis, I., Cicirelli, V., Mangano, S.,
Passantino, L., Lacalandra, G. M., Corriero, A. 2017a. Rearing in captivity affects spermatogenesis and sperm quality
in greater amberjack Seriola dumerili (Risso, 1810). Journal of Animal Science, 95: 4085-4100.
Zupa, R., Rodríguez, C., Mylonas, C. C., Rosenfeld, H., Fakriadis, I., Papadaki, M., Pérez, J. A., Pousis, C., Basilone,
G., Corriero, A. 2017b. Comparative study of reproductive development in wild and captive-reared greater amberjack
Seriola dumerili (Risso,1810). PLoS ONE 12(1): e0169645
The species-area relationship in centipedes (Myriapoda: Chilopoda): a comparison between Mediterranean island groups
No full textThe present study article examines the shapes of centipede species–area relationships (SARs) in the Mediterranean islands, compares the results of the linear form of the power model between archipelagos, discusses biological significance of the power model parameters with other taxa on the Aegean archipelago, and tests for a significant small-island effect (SIE). We used 11 models to test the SARs and we compared the quality-of-fit of all candidate models. The power function ranked first and Z-values was in the range 0.106–0.334. We assessed the presence of SIEs by fitting both a continuous and discontinuous breakpoint regression model. The continuous breakpoint regression functions never performed much better than the closest discontinuous model as a predictor of centipede species richness. We suggest that the relatively low Z-values in our data partly reflect better dispersal abilities in centipedes than in other soil invertebrate taxa. Longer periods of isolation and more recent island formation may explain the somewhat lower constant c in the western Mediterranean islands compared to the Aegean islands. Higher breakpoint values in the western Mediterranean may also be a result of larger distance to the mainland and longer separation times. Despite the differences in the geological history and the idiosyncratic features of the main island groups considered, the overall results are quite similar and this could be assigned to the ability of centipedes to disperse across isolation barriers
Spectrographic analysis of colourants of cultural items: from a qualitative to a semi-quantitative data treatment through BCTs
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