Chitin-based scaffolds are an integral part of the skeleton of the marine demosponge Ianthella basta

Abstract

The skeletons of demosponges, such as Ianthella basta, are known to be a composite material containing organic constituents. Here, we show that a filigree chitin-based scaffold is an integral component of the I. basta skeleton. These chitin-based scaffolds can be isolated from the sponge skeletons using an isolation and purification technique based on treatment with alkaline solutions. Solid-state 13 C NMR, Raman, and FT-IR spectroscopies, as well as chitinase digestion, reveal that the isolated material indeed consists of chitin. The morphology of the scaffolds has been determined by light and electron microscopy. It consists of cross-linked chitin fibers approximately 40-100 nm in diameter forming a micro-structured network. The overall shape of this network closely resembles the shape of the integer sponge skeleton. Solid-state 13 C NMR spectroscopy was used to characterize the sponge skeleton on a molecular level. The 13 C NMR signals of the chitin-based scaffolds are relatively broad, indicating a high amount of disordered chitin, possibly in the form of surfaceexposed molecules. X-ray diffraction confirms that the scaffolds isolated from I. basta consist of partially disordered and loosely packed chitin with large surfaces. The spectroscopic signature of these chitin-based scaffolds is closer to that of α-chitin than β-chitin.

Diatom frustules as a biomaterial: effects of chemical treatment on organic material removal and mechanical properties in cleaned frustules from two Coscinodiscus species

“…An organic matrix envelopes the frustules in vivo [20] and the cleaning protocol must handle a variety of compounds: amino acid derivatives [21] , [22] , long-chain polyamines (LCPAs) [23] , chitin [24] and polysaccharides [25] . Some of the organic molecules are enclosed within the biosilica in a phase separation process [26] .…”

Growth and regeneration of the elephant ear sponge Ianthella basta (Porifera)

“…While there has been renewed interest in this species for biomedical applications (Bergquist & Kelly-Borges, 1995;Brunner et al, 2009), little is known about its ecology and demography. Because the US NAVY has large scale dredging plans for Apra Harbor, more detailed knowledge of I. basta ecology and demography is needed to adequately assess mediation for destroyed coral reef areas.…”

“…Within the last years, several studies investigated I. basta with regard to its chitin-based skeleton (Ehrlich et al, 2007a(Ehrlich et al, , b, 2010aBrunner et al, 2009). These chitin-based scaffolds are of high interest for many biomedical applications like tissue engineering and biomedicine (e.g., Maeda et al, 2008;Jayakumar et al, 2010).…”

“…Another reason to investigate the natural growth rate of I. basta is recent studies describing its unusual chitin skeleton and the potential of such skeletons in biomedical applications (Brunner et al, 2009;Ehrlich et al, 2010a, b). However, the use of marine natural products in general and of the identified chitin scaffold in particular is restricted by supply limitations (e.g.…”

Species-specific shells: Chitin synthases and cell mechanics in molluscs

“…Right, Jmol image of the nucleotide-diphosphosugar binding site of SpsA (http://www.cazy.org/ GT2_structure.html; PDB ID: 1QGS) [43]. Sponges, probably the most ancient multicellular organisms [56,57], also produce chitin and minerals [58,59]. The shells of Brachiopods -regarded as "living fossils" -and gastropods contain chitin sheets interspaced by mineral phases [60,61].…”