Siliceous spicules and skeleton frameworks in sponges: Origin, diversity, ultrastructural patterns, and biological functions

@article{riz2003SiliceousSA,
  title={Siliceous spicules and skeleton frameworks in sponges: Origin, diversity, ultrastructural patterns, and biological functions},
  author={Mar{\'i}a Jes{\'u}s {\'U}riz and Xavier Turon and Mikel A. Becerro and Gemma Agell},
  journal={Microscopy Research and Technique},
  year={2003},
  volume={62}
}
Silica deposition is a fundamental process in sponges. Most sponges in the Classes Demospongiae and Hexactinellida secrete siliceous elements, which can subsequently fuse, interlock with each other, or form three‐dimensional structures connected by spongin. The resulting skeletal frameworks allow sponges to grow upwards and facilitate water exchange with minimal metabolic cost. Several studies on sponge skeletogenesis have been published. We are beginning to understand the mechanisms of spicule… 

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References

SHOWING 1-10 OF 162 REFERENCES

Biochemistry and cell biology of silica formation in sponges

TLDR
It is concluded that both iron and silicate stimulate the activity of silicatein and it is proposed that the growing spicules are surrounded by the scavenger receptor which might be considered as a docking molecule for the collagen matrix into which the spicule are embedded.

Silicification Processes in Sponges: Geodia Asters and the Problem of Morphogenesis of Spicule Shape

TLDR
The pattern of development of complex siliceous structures (asters) in Geodia cydonium involve the formation of short, terminal processes which then become fused together and finally form a star-shaped pattern, difficult to invoke the presence of a centrally located silicification center as a basis for this sequence of morphogenesis.

Ultrastructure and Deposition of Silica in Sponges

Sponges, the most primitive multicellular animals, are able to concentrate and precipitate three mineral elements: iron, calcium, and silicon. Iron forms small granules deposited on and within the

Form and Distribution of Silica in Sponges

TLDR
In a number of lines of demosponges and hexactinellids there is a tendency toward the deposition of secondary deposits of silica on the basic spicule forms with the resulting formation of rigid skeletal frameworks composed of fused or interlocking spicules.

Expression of silicatein and collagen genes in the marine sponge Suberites domuncula is controlled by silicate and myotrophin.

TLDR
It was found that after increasing the concentration of soluble silicate in the seawater medium from around 1 microM to approximately 60 microM, this gene is strongly upregulated and the expression of collagen is also upregulated in those primmorphs which were treated with recombinant myotrophin obtained from the same sponge.

Microstructure variation in sponges sharing growth form: The encrusting demosponges Dysidea avara and Crambe crambe

TLDR
There is wide scope for microarchitectural patterns, even in species with similar growth form, and that structural and cytological characters may prove to be useful descriptors of biological strategies in sponges.

An ultrastructural study of silica deposition in the freshwater sponge Spongilla lacustris.

Fiber diffraction study of spicules from marine sponges

TLDR
A synchrotron radiation fiber diffraction structural study of the axial filament of siliceous spicules from two species of marine sponges indicated that the protein units in the filament of both samples were highly organized.

Functional Morphology and Morphological Variation

TLDR
All sponges, except the Hexactinellida, possess two well-defined types of epithelial tissue: pinacocytes and choanocytes and both of these tissues have been recently confirmed as syncytial.
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