Sponge cell reactivity to various forms of silica

Abstract

Several sponge species incorporate a wide range of foreign material. Whether such material is actively selected by the sponge is controversial. Here we compare the available suspended matter and the sediment incorporated in the tissue of the demosponge Chondrosia reniformis. Field observations and laboratory experiments indicate that this species selects and incorporates only siliceous materials, in particular quartz particles and opal sponge spicules, avoiding carbonate particles. The reaction of ectosome cells of Chondrosia depends on the forms of silica: after settlement of crystalline quartz particles on the sponge surface, the pinacocytes contract uniformly, giving rise to a ruffled surface that remains throughout the incorporation of foreign material. In contrast, the opal spicules elicit a motile response in pinacocytes, which cover the spicules as a result. After incorporation, while the opal spicules remain unaltered within sponge tissue, the engulfed quartz particles are quickly etched, reduced in size, and released from the sponge. The etching of quartz particles by C. reniformis is produced by ascorbic acid, and is the first evidence of such activity from the animal kingdom. Ascorbic acid has been found to change the quartz surface features, which leads to an increased radical production and a consequent dissolution of quartz. This process does not occur on opal spicules.

Molecular Cloning, Characterization, and Expression Analysis of a Prolyl 4-Hydroxylase from the Marine Sponge Chondrosia reniformis

“…This latter localization could be strictly related to a particular phenomenon taking place in these sponges which have the amazing capability to selectively engulf siliceous particles in the ectosome (Bavestrello et al 1998) and to etch quartz grains in the same district (Bavestrello et al 1995). The etching action, developed in a sort of fibrotic envelope around the quartz grains, is caused by a peculiar chemical reaction of ascorbic acid, abundant in these sponges (Cerrano et al 1999), slowly dissolving crystalline silica (Bavestrello et al 1995(Bavestrello et al , 2003. Thus, the local presence of soluble silicates as well as of ascorbic acid likely stimulates, in paracrine cells, both the production of collagen (either by soluble silicates (Pozzolini et al 2012) and by ascorbic acid (Lyons and Schwarz 1984)) and of P4H (by ascorbic acid solely, as reported here) strengthening the fibrotic envelope around the engulfed quartz particles.…”

Molecular Characterization of a Nonfibrillar Collagen from the Marine Sponge Chondrosia reniformis Nardo 1847 and Positive Effects of Soluble Silicates on Its Expression

“…Indeed, we have previously demonstrated the amazing capability of C. reniformis to incorporate and dissolve crystalline quartz, with the consequent production of dissolved silicon compounds, using ascorbic acid as reactant (Bavestrello et al 1995). In this respect, we also addressed the role of siliceous sediments incorporated inside the sponge ectosome as a possible tool to strengthen the sponge collagenous structure (Bavestrello et al 2003). Some years later, Brümmer and co-workers showed a remarkable C. reniformis silicon uptake from the aqueous medium, and this property was related to possible induction of collagen biosynthesis (Nickel and Brümmer 2003).…”

Temporal variations in growth and reproduction of Tedania anhelans and Chondrosia reniformis in the North Adriatic Sea

“…In particular, nano-and pico-plankton are abundant especially in summer time in the North Adriatic Sea, and they could represent an important food supply during this period (Gilmartin & Revelante, 1980;Fonda Umani, 1996;Bernardi Aubry et al, 2006;Zuschin & Stachowitshc, 2009) that is generally considered oligotrophic for the Mediterranean Sea (Coma et al, 2000). C. reniformis is able to incorporate foreign materials, selecting sand grains of crystalline quartz and amorphous siliceous opaline spicules (Bavestrello et al, 1998a, b) and the collagenous production in C. reniformis may be enhanced by quartz dissolution (Bavestrello et al, 2003;Cerrano et al, 2007). This lead us to consider that, due to the high sedimentation rates characterizing the Conero Promontory, the sponge growth could be enhanced by the incorporation of large amounts of sediments.…”