Results 171 to 180 of about 1,483 (201)

Regeneration rates of a sublittoral demosponge

Journal of the Marine Biological Association of the United Kingdom, 2002
The effect of water flow rate on the regeneration rate of the temperate sponge Cliona celata was investigated at two sites experiencing fast and slight current flow respectively at Lough Hyne, Co. Cork, Ireland. Faster regeneration rates were found in sponges living in high current areas which may be due to an increased amount of potential food ...
openaire   +1 more source

MicroRNA expression during demosponge dissociation, reaggregation, and differentiation and a evolutionarily conserved demosponge miRNA expression profile

Development Genes and Evolution, 2015
Demosponges share eight orthologous microRNAs (miRNAs), with none in common with Bilateria. Biological functions of these demosponge miRNAs are unknown. Bilaterian miRNAs are key regulators of cellular processes including cell cycle, differentiation, and metabolism.
openaire   +2 more sources

Comparative study of spiculogenesis in demosponge and hexactinellid larvae

Microscopy Research and Technique, 2003
AbstractSpicule deposition was studied by electron microscopy in fixed embryos and larvae of the haplosclerid sponge Reniera sp. and the hexactinellid Oopsacas minuta. Spicules form in centrally located vacuoles within cells and within syncytia, as in the adult sponges. In Reniera, scleroblasts differentiate from micromeres prior to gastrulation.
openaire   +2 more sources

The GABAergic‐like system in the marine demosponge Chondrilla nucula

Microscopy Research and Technique, 2007
AbstractGamma‐amino butyric acid (GABA) is believed to be the principal inhibitory neurotransmitter in the mammalian central nervous system, a function that has been extended to a number of invertebrate systems. The presence of GABA in the marine demosponge Chondrilla nucula was verified using immunofluorescence detection and high‐pressure liquid ...
RAMOINO, PAOLA, GALLUS, LORENZO, PALUZZI S, RAITERI, LUCA, DIASPRO, ALBERTO GIOVANNI, FATO, MARCO MASSIMO, BONANNO, GIAMBATTISTA, TAGLIAFIERRO, GRAZIA, FERRETTI C, MANCONI R.   +9 more
openaire   +4 more sources

Molecular biology of demosponge axial filaments and their roles in biosilicification

Microscopy Research and Technique, 2003
AbstractFor hundreds of years, the skeletal elements of marine and freshwater sponges have intrigued investigators with a diverse array of remarkably complex morphologies. Early studies of demosponge monaxonal megascleres revealed the presence of a central organic axial filament running their entire length. Until recently, however, the precise function
James C, Weaver, Daniel E, Morse
openaire   +2 more sources

Formation of siliceous spicules in the marine demosponge Suberites domuncula

Cell and Tissue Research, 2005
The siliceous skeleton of demosponges is constructed of spicules. We have studied the formation of spicules in primmorphs from Suberites domuncula. Scanning electron microscopy and transmission electron-microscopical (TEM) analyses have revealed, in the center of the spicules, an axial canal that is 0.3-1.6 microm wide and filled with an axial filament.
Werner E G, Müller, Matthias, Rothenberger, Alexandra, Boreiko, Wolfgang, Tremel, Andreas, Reiber, Heinz C, Schröder   +5 more
openaire   +2 more sources

New mechanisms in demosponge spicule formation

Journal of the Marine Biological Association of the United Kingdom, 2001
A new mechanism of demosponge spicule formation was recognized during taxonomic studies of bioeroding sponges (Porifera: Demospongiae: Clionidae). To date different spicule types have been explained by matching structures to their organic matrix, the axial thread. Bulbous structures, however, do not have an organic counterpart.
openaire   +1 more source

The demosponge Pseudoceratina purpurea as a new source of fibrous chitin

International Journal of Biological Macromolecules, 2018
Among marine demosponges (Porifera: Demospongiae), only representatives of the order Verongiida have been recognized to synthetize both biologically active substances as well as scaffolds-like fibrous skeletons made of structural aminopolysaccharide chitin.
Sonia Żółtowska- Aksamitowska, Mikhail V. Tsurkan, Swee–Cheng Lim, Heike Meissner, Konstantin Tabachnick, Lamiaa A. Shaala, Diaa T.A. Youssef, Viatcheslav N. Ivanenko, Iaroslav Petrenko, Marcin Wysokowski, Nicole Bechmann, Yvonne Joseph, Teofil Jesionowski, Hermann Ehrlich   +13 more
openaire   +2 more sources

Cyathophycus and the origin of demosponges

Lethaia, 2003
The relationships between the poriferan classes are currently obscure. Molecular phylogenies appear to be reaching a consensus that the hexactinellids and demosponges are closely related, despite previous attempts to separate the Hexactinellida from other sponges on cytological grounds, but the details of the transition are unknown.
openaire   +1 more source

Diversité des demosponges tunisiennes

2006
مراجعة الدّراسات المتعلّقة بالنظام الإسفنجي من ناحية وبالأنظمة البحريّة القاعيّة وغيرها الّتي تهتمّ ببيان التنوّع البيولوجي البحري التونسي من ناحية أخرى، مكّنتنا من تصنيف 143 نوع من الإسفنج (ديموسينج) لها توزيع مختلف حسب الجهات الشماليّة والشرقيّة والجنوبيّة للبلاد التونسيّة.
Ben Mustapha, K., Zarrouk, S, Souissi, A., El Abed, A.   +3 more
openaire   +1 more source