Search results for "POMA."
showing 10 items of 183 documents
Spatiotemporal and gender-specific parasitism in two species of gobiid fish
2018
Parasitism is considered a major selective force in natural host populations. Infections can decrease host condition and vigour, and potentially influence, for example, host population dynamics and behavior such as mate choice. We studied parasite infections of two common marine fish species, the sand goby (Pomatoschistus minutus) and the common goby (Pomatoschistus microps), in the brackish water Northern Baltic Sea. We were particularly interested in the occurrence of parasite taxa located in central sensory organs, such as eyes, potentially affecting fish behavior and mate choice. We found that both fish species harbored parasite communities dominated by taxa transmitted to fish through …
A study on Pomatoschistus tortonesei Miller 1968 (Perciformes, Gobiidae) reveals the Siculo-Tunisian Strait (STS) as a breakpoint to gene flow in the…
2009
The current genetic structure of P. tortonesei, exclusively inhabiting lagoons, may reflect a Plio-Pleistocene colonisation of an ancestor line which has undergone phases of population decline and expansion, following alternate cooling phases. Regarding the calculation of divergence time, it has been estimated that P. tortonesei seems to be the most recent species within the Pomatoschistus genus. It appears also that the discrepancy of P. tortonesei into two distinct phyletic lineages occurred 0.1 Mya. Recurring shifts in sea level and sea surface temperatures of Mediterranean Sea caused the desiccation of shallower lagoons and the consequent bottleneck phenomena of the brackish populations…
A new metallothionein gene from the giant keyhole limpet Megathura crenulata.
2003
Abstract Metallothioneins (MTs) are small soluble proteins ubiquitously expressed in animals and plants. Different isoforms are present in deuterostomes and protostomes. They do not differ greatly in primary structure, but are clearly distinguishable. Here, I present the gene and the complete cDNA of a novel MT from the mollusk Megathura crenulata . This protein is closely related to the Cu-inducible MTs of the vineyard snail Helix pomatia , but has also some minor sequence features typical of Cd-inducible isoforms of H . pomatia and other molluscs. Overall, the deduced primary structure is similar to the known molluscan MTs, but in addition possesses an insertion of 5 amino acids not found…
Characterization of mitotic and meiotic, chromosomes of the vermetid gastropodDendropoma (Novastoa) Petraeum(Monterosato, 1884) (Mollusca, Caenogastr…
1997
Abstract The vermetid gastropod Dendropoma (Novastoa) petraeum from the Northwestern coast of Sicily was investigated karyologically. The count of spermatocyte bivalents at diakinesis gave the haploid number of this species as n=17. The count of mitotic chromosomes in males, females and early developing embryos gave the diploid number as 2n=34. Irrespective of sex, the karyotype of D. petraeum consists of 17 homomorphic chromosome pairs, of which 8 are metacentric, 4 subtelocentric and 5 acrocentric. This species is characterized by the presence of two chromosomes per cell involved in nucleolus organization (NOR) and by a low amount of constitutive heterochromatin.
Myxobolus albin. sp. (Myxozoa) from the Gills of the Common GobyPomatoschistus micropsKrøyer (Teleostei: Gobiidae)
2009
A recent investigation into the myxozoan fauna of common gobies, Pomatoschistus microps, from the Forth Estuary in Scotland, revealed numerous myxosporean cysts within the gill cartilage. They were composed of polysporous plasmodia containing myxobolid spores that were morphologically different from the other known species of Myxobolus and from the myxosporeans previously recorded from this host (i.e. the ceratomyxid Ellipsomyxa gobii, infecting the gall bladder, and the kudoid Kudoa camarguensis, infecting the muscle tissues). Spores were ovoid, 9.4 x 9.1 microm with a thickness of 6.6 microm, with two pyriform polar capsules, the polar filaments of which had four to five turns. Molecular …
A new marker for sea surface temperature trend during the last centuries in temperate areas: Vermetid reef
2004
The presence of Vermetid reefs in temperate waters, their diffusion in the Mediterranean Sea, and the possibility of performing 14 C ages allowed the use of Vermetids as an indicator of sea level changes. We present new data on sea climate trend fluctuations that could be interpreted as Sea Surface Temperature (SST) variations, recorded on Vermetid (Dendropoma petraeum) reefs, by means of isotopic analysis. The isotopic records show positive values of the d 18 O relative to present-day values in the period between 1600 and 1850 AD; this deviation occurs in association with the climatic cooling event known as Little Ice Age (LIA). Subsequently, we can observe the warming trend that character…
A comparative genetic study on exploited vs. Unperturbed wild populations of Helix Pomatia (L., 1758): preliminary results
2021
Helix pomatia is one of the most well known species of land snails across Europe and it presents economical importance due to its consumption as food. The preliminary results of the genetic comparison between two populations, one of them under the pressure of exploitation, are presented here. As expected, most indices revealed a disequilibrium in the exploited population, with the exeption of the allelic pattern which was similar among the two studied populations.
Data from: Phylogenomics of Lophotrochozoa with consideration of systematic error
2021
Phylogenomic studies have improved understanding of deep metazoan phylogeny and show promise for resolving incongruences among analyses based on limited numbers of loci. One region of the animal tree that has been especially difficult to resolve, even with phylogenomic approaches, is relationships within Lophotrochozoa (the animal clade that includes molluscs, annelids, and flatworms among others). Lack of resolution in phylogenomic analyses could be due to insufficient phylogenetic signal, limitations in taxon and/or gene sampling, or systematic error. Here, we investigated why lophotrochozoan phylogeny has been such a difficult question to answer by identifying and reducing sources of sys…
Data from: Phylogenomics of Lophotrochozoa with consideration of systematic error
2016
Phylogenomic studies have improved understanding of deep metazoan phylogeny and show promise for resolving incongruences among analyses based on limited numbers of loci. One region of the animal tree that has been especially difficult to resolve, even with phylogenomic approaches, is relationships within Lophotrochozoa (the animal clade that includes molluscs, annelids, and flatworms among others). Lack of resolution in phylogenomic analyses could be due to insufficient phylogenetic signal, limitations in taxon and/or gene sampling, or systematic error. Here, we investigated why lophotrochozoan phylogeny has been such a difficult question to answer by identifying and reducing sources of sys…
Ocean acidification and elevated temperature negatively affect recruitment, oxygen consumption and calcification of the reef-building Dendropoma cris…
2019
Expected temperature rise and seawater pH decrease may affect marine organism fitness. By a transplant experiment involving air-temperature manipulation along a natural CO2 gradient, we investigated the effects of high pCO(2) (similar to 1100 mu atm) and elevated temperature (up to +2 degrees C than ambient conditions) on the reproductive success, recruitment, growth, shell chemical composition and oxygen consumption of the early life stages of the intertidal reef-building vermetid Dendropoma cristatum. Reproductive success was predominantly affected by temperature increase, with encapsulated embryos exhibiting higher survival in control than elevated temperature conditions, which were in t…