Analysis of silicatein gene expression and spicule formation in the demosponge Amphimedon queenslandica

  title={Analysis of silicatein gene expression and spicule formation in the demosponge Amphimedon queenslandica},
  author={A Gauthier},
The skeletal elements in most sponges are siliceous spicules. These are fabricated into species-specific sizes and shapes. Demosponges, in particular, have specialised cells called sclerocytes that possess the unique ability to synthesise biosilica and these spicules. Underlying the diversity of demosponge spicules morphology is a conserved protein, called silicatein. This thesis aims to investigate the process of spiculogenesis in the different developmental stages of the demosponge Amphimedon… 

Silicatein expression in Haliclona indistincta (Phylum Porifera, Order Haplosclerida) at different developmental stages

Variants containing CHN or C/SQN at the active site appear more common in sponges from the Haplosclerida, indicating a possible ability of active sites with these alternative amino acids to condense silica.

Interdependent photo- and chemosensory systems regulate larval settlement in a marine sponge

Interactions between light and biochemical cues at behavioural and molecular levels during larval ontogeny in a sponge are explored, for the first time, and light perturbs ontogenetic changes in gene expression and prevents settlement in response to biochemical cues, demonstrating strong interdependencies between photo- and chemosensory systems.

Molecular and behavioural evidence that interdependent photo ‐ and chemosensory systems regulate larval settlement in a marine sponge

It is found that larvae do not settle in response to biochemical cues if maintained in constant light, and data suggest that photo‐ and chemosensory systems interact to regulate larval settlement via nitric oxide and cyclic guanosine monophosphate signalling in this sponge, which belongs to one of the earliest‐branching animal phyla.



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.

Dynamics of spicule production in the marine sponge Hymeniacidon perlevis during in vitro cell culture and seasonal development in the field

Silicatein expression in the bloom stage was more than 100 times higher than that in the other stages and was correlated with the spicule developmental stage, and the trend of spicules formation in field-grown sponges was consistent with the trend in cell culture.

Silicatein expression in the hexactinellid Crateromorpha meyeri: the lead marker gene restricted to siliceous sponges

The morphology of the spicules (diactines and stauractines) of the hexactinellid Crateromorpha meyeri is described and it is shown that anti-silicatein antibodies react specifically with the proteinaceous matrix of the C.meyeri spicule, indicating that silicatein is an autapomorphic molecule common to both classes of siliceous sponges.

Silicatein Genes in Spicule-Forming and Nonspicule-forming Pacific Demosponges

The results suggest that silicateins could participate also in the function(s) unrelated to spiculogenesis, and identify, for the first time, silicatein genes (AcSilA and AcSilB) in nonspicule-forming marine sponge, Acаnthodendrilla sp.

Selenium affects biosilica formation in the demosponge Suberites domuncula

It is concluded that selenium has a stimulatory effect on the formation of siliceous spicules in sponges, and it may be involved in the enzymatic synthesis of biosilica components.

Occurrence of a Silicatein Gene in Glass Sponges (Hexactinellida: Porifera)

Comparative sequence analysis indicates high sequence identity of the A. schulzei silicatein with demosponge silicateins described previously, and a phylogenetic analysis indicates that the AuSil-Hexa protein belongs to silicatesins.

Co-expression and Functional Interaction of Silicatein with Galectin

A scheme that outlines the matrix (galectin/silicatein)-guided appositional growth of spicules through centripetal and centrifugal synthesis and deposition of biosilica is proposed and is relevant for potential (nano)-biotechnological applications of silicatein in the formation of surface coatings.

Formation of spicules by sclerocytes from the freshwater spongeEphydatia muelleri in short-term cultures in vitro

The results demonstrate that the establishment of short-term cell cultures from E. muelleri is possible; however, future studies must be undertaken to identify the growth factors required for a permanent culture of sponge cells.