Silica spicules and axial filaments of the marine sponge Stelletta grubii (Porifera, Demospongiae)

  title={Silica spicules and axial filaments of the marine sponge Stelletta grubii (Porifera, Demospongiae)},
  author={Tracy L. Simpson and P. F. Langenbruch and Lidia Scalera-Liaci},
SummaryIn all cases an organic axial filament within the silica spicules of Stelletta grubii forms the core of the major axes of the glass. In the small, star-shaped silica spicules (asters) the filament is shown for the first time to be radial with an enlarged center; in the large four-rayed spicules (triaenes) it is four-rayed; and in the large single-rayed spicules (oxeas) the filament is single-rayed. In situ, the filament is not dissolved by boiling nitric acid and thus is apparently… 

Fiber diffraction study of spicules from marine sponges

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.

Molecular biology of demosponge axial filaments and their roles in biosilicification

The silicateins, the most abundant proteins comprising the axial filaments of these spicules, prove to be members of a well‐known superfamily of proteolytic and hydrolytic enzymes and can be easily collected after silica demineralization with hydrofluoric acid.

Comparative study of spiculogenesis in demosponge and hexactinellid larvae

  • S. Leys
  • Biology
    Microscopy research and technique
  • 2003
The elaboration and organization of the spicules differ markedly in cellular and syncytial sponges and appear to be an outcome of the very distinct cellular differentiation and larval morphogenesis that occur in each of these groups.

Giant siliceous spicules from the deep-sea glass sponge Monorhaphis chuni.

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

The process of silica deposition in sponges at the molecular and cellular levels, as well as the biological and ecological functions of spicules and skeletons are reviewed.

The unique invention of the siliceous sponges: their enzymatically made bio-silica skeleton.

It is proposed that the key innovation that allowed the earliest metazoans to form larger specimens was the enzyme silicatein, crucial for the formation of the siliceous skeleton.

Utilizing sponge spicules in taxonomic, ecological and environmental reconstructions: a review

The silicon isotope compositions in spicules are being increasingly often used to estimate the level of silicic acid in the marine settings throughout the geological history, which enables to reconstruct the past silica cycle and ocean circulation.

Primary structure and post-translational modifications of silicatein beta from the marine sponge Petrosia ficiformis (Poiret, 1789).

Results demonstrate that P. ficiformis spicules contain almost only silicatein beta, and several post-translational modifications, like methylations at the N-terminal region, three phosphorylation sites, and the oxidation of a histidine and of a cysteine to cysteic acid are described.



Form and Distribution of Silica in Sponges

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.

Cortical and endosomal structure of the marine sponge Stelletta grubii

Observations suggest that the enigmatic species Chondrosia reniformis is closely related to S. grubii and that it should be placed within or near the astrophorids.

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

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

Electron microscopy of siliceous spicules from the freshwater sponge Heteromyenia.

  • R. W. Drum
  • Chemistry
    Journal of ultrastructure research
  • 1968

Localization of Two Brominated Metabolites, Aerothionin and Homoaerothionin, in Spherulous Cells of the Marine Sponge Aplysina fistularis (=Verongia thiona)

Energy dispersive X-ray microanalysis was used to localize the two brominated natural products in the tissues of a marine demosponge, Aplysina fistularis, for the first localization of any secondary metabolite at the cellular or sub-cellular level in any marine invertebrate.

Siliceous sponge spicules in coral reef sediments

Experimental etching with hydrofluoric acid indicated that silica deposition occurs in a recognizable pattern in common sponge microscleres, indicating that recycling of locally dissolved silica appears to be important for the growth of many off-shore reef sponges.


A substantial portion of the axial filament of the spicules of silicious sponges is protein, and it is feasible to follow the course ofsilicious deposition in spicule using C14 or H3 in protein precursors.

Mechanism of Internal Stratification of Siliceous Sponge Spicules

Internal fine structure in spicule fossils would provide a valuable comparison with present day spicules and may offer clues as to climatological or ecological conditions in that period.