Shipwrecks, ascidians and modiolarca subpicta (Bivalvia, Mytildae, Musculinae)

The ovulid gastropod Xandarovula patula (Pennant, 1777) was found 14.vi.2011 on the soft coral Alcyonium digitatum Linnaeus, 1758 (Dead man’s fingers) during a dive in the central North Sea on the wreck ‘Jeanette Kristina’ on the Dutch Dogger Bank. Later on additional specimens were found, sometimes with egg-capsules, on A. digitatum again, at two locations on the Dutch Cleaver Bank. The species has previously been recorded from the Atlantic coast of southern Spain to the western end of The English Channel, with scattered records from the west coasts of Ireland and Britain, as far north as the Orkney’s. More recently it has been reported from most Irish coasts, several parts of the Scottish coast and also from some places in the North Sea. We here present the first record of X. patula for the Dutch part of the continental shelf. The specimens and their egg-capsules from both the Dogger Bank and Cleaver Bank, indicate that this species is autochthonous in the central North Sea

The Japanese oyster drill <i>Ocinebrellus inornatus</i> (Récluz, 1851) (Mollusca, Gastropoda, Muricidae), introduced to the Limfjord, Denmark

The predatory neogastropod Ocinebrellus inornatus was first reported from Europe in W France in 1995 and has since been detected at other sites in NW and N France and The Netherlands. It is native to the North Pacific where it preys on the Pacific oyster Crassostrea gigas. Here we report on the occurrence of the species in beds of European oysters (Ostrea edulis) in the Limfjord, NW Jutland, Denmark. The morphology-based identification has been confirmed by genetic analysis. The species was probably introduced with oysters imported from France in the 1970s and 1980s. The invasion is still relatively localized but as the species has established a reproductive population, it may eventually spread to other parts of the fjord and in time pose a problem to the oyster fishery. The species’ invasion history is reviewed

On the identity of broad-shelled mussels (Mollusca, Bivalvia, Mytilus) from the Dutch delta region

Late Quaternary (Eemian) deposits of the Netherlands contain shells that resemble those of living Mytilus galloprovincialis. Similar broad-shelled mytilids also occur in estuaries of the southwestern Netherlands together with slender individuals typical of M. edulis. We sampled living mussels along a depth gradient in the Oosterschelde to a) investigate whether a relation exists between shell shape and depth, b) test if the broadshelled specimens might represent M. galloprovincialis (or a hybrid with M. edulis) and c) assess by inference if the Quaternary specimens might be attributed to M. galloprovincialis as well. In order to do so, we compared genetic (length polymorphism of Me 15/16, COIII sequences and AFLPs) and shellmorphological characteristics (juvenile L/W ratios and socalled Verduin parameters) of the same specimens. The obtained dataset indicates that all studied mussels from the Oosterschelde should be attributed to M. edulis, including those with broad shell outlines. No correlation of shell-morphology and depth-distribution was found. The worn and generally damaged state of the Eemian specimens precluded measurement of the Verduin parameters, while juvenile L/W ratios turned out not to be diagnostic. Therefore the shell characters examined in this study are insufficient to demonstrate the possible presence of M. galloprovincialis shells in Quaternary deposits of the Netherlands.

The Development of the Vascular System in Quail Embryos: A Combination of Microvascular Corrosion Casts and Immunohistochemical Identification

Although vascular casts, obtained by injection with methacrylates, are frequently used to investigate the adult vascular system, little data are available for embryonic stages. In this paper we use MercoxR in quail embryos in the period of 2 to 7 days after incubation. The microvascular corrosion casts were evaluated in the scanning electron microscope (SEM) with special attention to the development and remodelling of the large arteries and veins. Our results show that the remodelling of the large arteries and veins together with their developing tributary vessels can be visualized from very early embryonic stages onwards. However, complete replication of a developing vascular system depends on diameter and regularity of the lumen. In the stages investigated, the vascular lumen, even of the largest vessels, is still very irregular. Detailed cellular characteristics like nuclear impressions of endothelial cells, as often seen in adult material, were seldom found in the embryos. To examine whether blind-ending sprouts are completely or incompletely replicated in a developing vascular system, additional series of quail embryos were stained immunohistochemically with a monoclonal antibody (MB1) specific for endothelial and hemopoietic cells. It seems that a plexus consisting of endothelial precursors (endothelial cells lacking a lumen) is present in the developing organ before the formation of a lumen and assembly into vessels, which are connected to an adjacent artery or vein. Expansion of the vascular system may in part be due to incorporation of these endothelial precursors in the wall of existing vessels

Left-right asymmetric expression of dpp in the mantle of gastropods correlates with asymmetric shell coiling

This is the final version of the article. Available from BMC via the DOI in this record.BACKGROUND: Various shapes of gastropod shells have evolved ever since the Cambrian. Although theoretical analyses of morphogenesis exist, the molecular basis of shell development remains unclear. We compared expression patterns of the decapentaplegic (dpp) gene in the shell gland and mantle tissues at various developmental stages between coiled-shell and non-coiled-shell gastropods. RESULTS: We analyzed the expression patterns of dpp for the two limpets Patella vulgata and Nipponacmea fuscoviridis, and for the dextral wild-type and sinistral mutant lineage of the pond snail Lymnaea stagnalis. The limpets had symmetric expression patterns of dpp throughout ontogeny, whereas in the pond snail, the results indicated asymmetric and mirror image patterns between the dextral and sinistral lineages. CONCLUSION: We hypothesize that Dpp induces mantle expansion, and the presence of a left/right asymmetric gradient of the Dpp protein causes the formation of a coiled shell. Our results provide a molecular explanation for shell, coiling including new insights into expression patterns in post-embryonic development, which should aid in understanding how various shell shapes are formed and have evolved in the gastropods.This study was supported by the JSPS Grants-in-Aid for Scientific Research 15104009

The grand canonical ABC model: a reflection asymmetric mean field Potts model

We investigate the phase diagram of a three-component system of particles on a one-dimensional filled lattice, or equivalently of a one-dimensional three-state Potts model, with reflection asymmetric mean field interactions. The three types of particles are designated as $A$, $B$, and $C$. The system is described by a grand canonical ensemble with temperature $T$ and chemical potentials $T\lambda_A$, $T\lambda_B$, and $T\lambda_C$. We find that for $\lambda_A=\lambda_B=\lambda_C$ the system undergoes a phase transition from a uniform density to a continuum of phases at a critical temperature $\hat T_c=(2\pi/\sqrt3)^{-1}$. For other values of the chemical potentials the system has a unique equilibrium state. As is the case for the canonical ensemble for this $ABC$ model, the grand canonical ensemble is the stationary measure satisfying detailed balance for a natural dynamics. We note that $\hat T_c=3T_c$, where $T_c$ is the critical temperature for a similar transition in the canonical ensemble at fixed equal densities $r_A=r_B=r_C=1/3$.Comment: 24 pages, 3 figure

The complete mitogenome of Cylindrus obtusus (Helicidae, Ariantinae) using Illumina next generation sequencing

Animal science

Left-right asymmetric expression of dpp in the mantle of gastropods correlates with asymmetric shell coiling

Background: Various shapes of gastropod shells have evolved ever since the Cambrian. Although theoretical analyses of morphogenesis exist, the molecular basis of shell development remains unclear. We compared expression patterns of the decapentaplegic (dpp) gene in the shell gland and mantle tissues at various developmental stages between coiled-shell and non-coiled-shell gastropods. Results: We analyzed the expression patterns of dpp for the two limpets Patella vulgata and Nipponacmea fuscoviridis, and for the dextral wild-type and sinistral mutant lineage of the pond snail Lymnaea stagnalis. The limpets had symmetric expression patterns of dpp throughout ontogeny, whereas in the pond snail, the results indicated asymmetric and mirror image patterns between the dextral and sinistral lineages. Conclusion: We hypothesize that Dpp induces mantle expansion, and the presence of a left/right asymmetric gradient of the Dpp protein causes the formation of a coiled shell. Our results provide a molecular explanation for shell, coiling including new insights into expression patterns in post-embryonic development, which should aid in understanding how various shell shapes are formed and have evolved in the gastropods.ArticleEVODEVO. 4:15 (2013)journal articl

Nitric oxide synthase-3 deficiency results in hypoplastic coronary arteries and postnatal myocardial infarction

Aims Hypoplastic coronary artery disease is a rare congenital abnormality that is associated with sudden cardiac death. However, molecular mechanisms responsible for this disease are not clear. The aim of the present study was to assess the role of nitric oxide synthase-3 (NOS3) in the pathogenesis of hypoplastic coronary arteries. Methods and results Wild-type (WT), NOS3 -/-, and a novel cardiac-specific NOS3 overexpression mouse model were employed. Deficiency in NOS3 resulted in coronary artery hypoplasia in foetal mice and spontaneous myocardial infarction in postnatal hearts. Coronary artery diameters, vessel density, and volume were significantly decreased in NOS3-/- mice at postnatal day 0. In addition, NOS3-/- mice showed a significant increase in the ventricular wall thickness, myocardial volume, and cardiomyocyte cell size compared with WT mice. Lack of NOS3 also down-regulated the expression of Gata4, Wilms tumour-1, vascular endothelial growth factor, basic fibroblast growth factor and erythropoietin, and inhibited migration of epicardial cells. These abnormalities and hypoplastic coronary arteries in the NOS3-/- mice were completely rescued by the cardiac-specific overexpression of NOS3. Conclusion Nitric oxide synthase-3 is required for coronary artery development and deficiency in NOS3 leads to hypoplastic coronary arteries. © 2014 The Author