Results 101 to 110 of about 197 (131)
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Formation of siliceous spicules in the marine demosponge Suberites domuncula
Cell and Tissue Research, 2005The 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 +5 more
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The demosponge Pseudoceratina purpurea as a new source of fibrous chitin
International Journal of Biological Macromolecules, 2018Among 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.
Żółtowska- Aksamitowska, Sonia +13 more
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New mechanisms in demosponge spicule formation
Journal of the Marine Biological Association of the United Kingdom, 2001A 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.
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Molecular biology of demosponge axial filaments and their roles in biosilicification
Microscopy Research and Technique, 2003AbstractFor 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
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Hypercalcified demosponges and the end-Permian extinction
Global and Planetary Change, 2010Abstract The hypothesis is presented here that the hypercalcified demosponges, characterized by a solid, largely external skeleton of spherulitic aragonite, or of high-Mg calcite, had symbiotic cyanobacteria, from the outset of their existence, that enabled them to precipitate their peculiar skeleton, and that both the skeleton and the cyanobacteria ...
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Diversité des demosponges tunisiennes
2006مراجعة 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. +3 more
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Cyathophycus and the origin of demosponges
Lethaia, 2003The 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.
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Some aspects of silica deposition in lithistid demosponge desmas
Microscopy Research and Technique, 2003AbstractTransmitted light microscope and SEM observations of various growth stages, including very young forms, of lithistid demosponge spicules called desmas provided a wealth of new observations on silica deposition in desmas of most lithistid demosponge groups.
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