Search results for "Polychaeta"

De novo transcriptome assembly and developmental mode specific gene expression of Pygospio elegans

2017

Species with multiple different larval developmental modes are interesting models for the study of mechanisms underlying developmental mode transitions and life history evolution. Pygospio elegans, a small, tube-dwelling polychaete worm commonly found in estuarine and marine habitats around the northern hemisphere, is one species with variable developmental modes. To provide new genomic resources for studying P. elegans and to address the differences in gene expression between individuals producing offspring with different larval developmental modes, we performed whole transcriptome Illumina RNA sequencing of adult worms from two populations and prepared a de novo assembly of the P. elegans…

Reducing the data-deficiency of threatened European habitats: Spatial variation of sabellariid worm reefs and associated fauna in the Sicily Channel,…

2017

Biogenic reefs, such as those produced by tube-dwelling polychaetes of the genus Sabellaria, are valuable marine habitats which are a focus of protection according to European legislation. The achievement of this goal is potentially hindered by the lack of essential empirical data, especially in the Mediterranean Sea. This study addresses some of the current knowledge gaps by quantifying and comparing multi-scale patterns of abundance and distribution of two habitat-forming species (Sabellaria alveolata and S. spinulosa) and their associated fauna along 190 km of coast on the Italian side of the Sicily Channel. While the abundance of the two sabellariids and the total number of associated t…

DNA Methylation and Potential for Epigenetic Regulation in Pygospio elegans.

2015

Transitions in developmental mode are common evolutionarily, but how and why they occur is not understood. Developmental mode describes larval phenotypes, including morphology, ecology and behavior of larvae, which typically are generalized across different species. The polychaete worm Pygospio elegans is one of few species polymorphic in developmental mode, with multiple larval phenotypes, providing a possibility to examine the potential mechanisms allowing transitions in developmental mode. We investigated the presence of DNA methylation in P. elegans, and, since maternal provisioning is a key factor determining eventual larval phenotype, we compared patterns of DNA methylation in females…

Revisión de las familias Capitellidae Grube, 1862 y Maldanidae Malmgren, 1867 (Annelida, Polychaeta) en el ámbito Íbero-Balear. Estudio morfológico, …

2015

Se ha realizado un estudio exhaustivo de todos los táxones pertenecientes a las familias Capitellidae y Maldanidae (Annelida, Polychaeta) en el ámbito Íbero-balear. Para ello, se han actualizado sus registros en este sector geográfico y se examinaron varias colecciones biológicas. Las colecciones estudiadas fueron la Colección de Referencia del Laboratorio de Biología Marina de la Universitat de València, la colección de Maldanidae del Muséum National d’Histoire Naturelle de Paris (MNHN) y las colecciones de Capitellidae y Maldanidae del Museo Nacional de Ciencias Naturales de Madrid (MNCN). Este estudio ha permitido la actualización del catálogo faunístico de las familias Capitellidae y Ma…

Tardigrades of Finland: new records and an annotated checklist

2020

Species checklists are powerful and important tools of communication between taxonomists and applied environmental biologists, which in turn lead to well-planned and successful conservation strategies and ecological studies. Despite this, only recently the interest on compiling systematic checklists is growing among taxonomists who study tardigrades—micrometazoans that inhabit almost every habitat worldwide. As the Finnish records of tardigrades (a.k.a. water bears) species are incomplete, outdated and no checklist has ever been compiled for this country, an easy-to-consult checklist is here reported. This checklist covers all Finnish tardigrade taxa identified in the past and in the 13 sam…

Long-lasting exocytosis and massive structural reorganisation in the egg periphery during cortical reaction inPlatynereis dumerilii(Annelida, Polycha…

1995

SummaryThe course of the cortical reaction in thePlatynereis dumeriliiegg is described from live observation and from sectioned fixed material and is found to differ in several aspects from the course of cortical reactions in better-known systems. Cortical granules are unusually numerous. They are discharged by exocytosis during a period of about 25 min following fertilisation (18°C). Most of the surplus membrane material brought to the egg surface by exocytosis is set free into the perivitelline space. Swelling of egg jelly precursor secreted by cortical granule exocytosis may be causal for the detachment of the vitelline envelope from the egg cell surface which, however, remains attached …

Polymorphism in Developmental Mode and Its Effect on Population Genetic Structure of a Spionid Polychaete, Pygospio elegans

2012

Population genetic structure of sedentary marine species is expected to be shaped mainly by the dispersal ability of their larvae. Long-lived planktonic larvae can connect populations through migration and gene flow, whereas species with nondispersive benthic or direct-developing larvae are expected to have genetically differentiated populations. Poecilogonous species producing different larval types are ideal when studying the effect of developmental mode on population genetic structure and connectivity. In the spionid polychaete Pygospio elegans, different larval types have been observed between, and sometimes also within, populations. We used microsatellite markers to study population st…

Rare earths, zirconium and hafnium distribution in coastal areas: The example of Sabella spallanzanii (Gmelin, 1791)

2016

The Zr, Hf, Y and lanthanide (REE) distribution in biological tissues of Sabella spallanzanii and Styela plicata species collected from two harbours from the northern Sicily is studied for providing information regarding the Zr, Hf and REE uptake from the environment. Previous studies determined the fractionation of dissolved REE scavenged on binding sites onto biological surfaces. By comparing the recognised shale-normalised REE patterns of studied samples with evidence from reference data, the observed behaviour of these elements in biological tissues of Sabella spallanzanii and Styela plicata is interpreted to result from the preferential uptake of intermediate REE onto carboxylic sites.…

Purificazione di una lectina calcio dipendente dal muco di Sabella spallanzanii (Polychaeta: Sabellidae)

2010

Transmission electron microscopical studies on some haemolymph proteins from the marine polychaete Nereis virens.

2001

Abstract The hexagonal bilayer haemoglobin molecule from Nereis virens has been investigated in a comparative study using several different negative stain electron microscopical specimen preparations (i.e. by conventional adsorption to continuous carbon support films, by the negative staining-carbon film technique and by negative staining across the holes of holey carbon support films with air-drying and rapid freezing/cryo-negative staining). The benefits and limitations of these different approaches are indicated, with the overall conclusion that negative staining with ammonium molybdate across holes creates the best possibilities for molecular imaging, and also has the potential for the …