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First report on chitinous holdfast in sponges (Porifera).

Authors :
Ehrlich H
Kaluzhnaya OV
Tsurkan MV
Ereskovsky A
Tabachnick KR
Ilan M
Stelling A
Galli R
Petrova OV
Nekipelov SV
Sivkov VN
Vyalikh D
Born R
Behm T
Ehrlich A
Chernogor LI
Belikov S
Janussen D
Bazhenov VV
Wörheide G
Source :
Proceedings. Biological sciences [Proc Biol Sci] 2013 May 15; Vol. 280 (1762), pp. 20130339. Date of Electronic Publication: 2013 May 15 (Print Publication: 2013).
Publication Year :
2013

Abstract

A holdfast is a root- or basal plate-like structure of principal importance that anchors aquatic sessile organisms, including sponges, to hard substrates. There is to date little information about the nature and origin of sponges' holdfasts in both marine and freshwater environments. This work, to our knowledge, demonstrates for the first time that chitin is an important structural component within holdfasts of the endemic freshwater demosponge Lubomirskia baicalensis. Using a variety of techniques (near-edge X-ray absorption fine structure, Raman, electrospray ionization mas spectrometry, Morgan-Elson assay and Calcofluor White staining), we show that chitin from the sponge holdfast is much closer to α-chitin than to β-chitin. Most of the three-dimensional fibrous skeleton of this sponge consists of spicule-containing proteinaceous spongin. Intriguingly, the chitinous holdfast is not spongin-based, and is ontogenetically the oldest part of the sponge body. Sequencing revealed the presence of four previously undescribed genes encoding chitin synthases in the L. baicalensis sponge. This discovery of chitin within freshwater sponge holdfasts highlights the novel and specific functions of this biopolymer within these ancient sessile invertebrates.

Details

Language :
English
ISSN :
1471-2954
Volume :
280
Issue :
1762
Database :
MEDLINE
Journal :
Proceedings. Biological sciences
Publication Type :
Academic Journal
Accession number :
23677340
Full Text :
https://doi.org/10.1098/rspb.2013.0339