Welcome to Gaia! :: View User's Journal | Gaia Journals

4.2.2. Ionic environment
At present, there is no information on the effects of pH variation on the mechanical state of sponges.
5. Comparative aspects and conclusions
In both animal models mutability is apparently based on a cell-mediated mechanism (Wilkie, 2005 and Wilkie et al., 2006). In echinoderms the putative effector CORM-3 are the JLCs. In sponges, functionally analogous cells have not been definitively identified yet, although the most promising candidates are the gray cells, which share some features with echinoderm JLCs. Independently of the effector cells, in both echinoderms and sponges the main mechanism governing mutability appears to be a variation in collagen interfibrillar cohesive forces and reciprocal sliding.
It is topical that in both echinoderms and sponges mutability is strongly affected by exogenous environmental factors (such as temperature, pH and ionic composition), although not always in the same way. For example decreasing temperature reduces mechanical resistance in starfish (Hidaka, 1983) but has the opposite effect in sponges (Fassini et al., 2012). On the other hand, [Ca2+] variations exert similar effects on both animal models.