As mentioned above, hMSCs started significant spreading after around 10 days of culture in the MMP-sensitive hydrogels. Our previous published studies revealed significant upregulation of chondrogenic marker genes Nitroprusside disodium dihydrate including sox9, collagen type II and aggrecan in hMSCs after only 3�C5 days of induction using TGFb3. We hypothesize that the majority of the hMSCs in the MMP-sensitive hydrogels had already moved down along the chondrogenic differentiation pathway before they started to spread in the hydrogels. Therefore, the cell spreading had little effect on these fully differentiated hMSCs. Further examination on the effect of cytoskeletal structure and cell shape on chondrogenic phenotype of the differentiated stem cells is needed. A limitation of this study is that the two bifunctional crosslinkers used, namely, the MMP-cleavable peptide and DTT, are of different length and chemical structures. Therefore, even though the two groups of hydrogels exhibited UNC669 similar level of swelling and mechanical stiffness and will likely have comparable permeability as well, the effect of different crosslinker properties as a confounding factor cannot be ruled out. Future study will explore the use of control crosslinkers that are structurally stable, biochemically inert and yet of similar length as that of the MMP-cleavable peptides. Mass bleaching of corals caused by global warming threatens the degradation of reef ecosystems worldwide. Coral bleaching involves a breakdown of the symbiotic relationships between reefbuilding corals and their symbiotic algae, dinoflagellates such as Symbiodinium. The genus Symbiodinium is currently classified into nine clades. Clade C is most often associated with corals, although corals occasionally switch their symbiotic algae. Especially after bleaching events, clade D Symbiodinium has been detected in corals. Flexibility in symbiotic associations has also been observed in the early growth stage of Acroporid corals infected by Symbiodinium algae from the environment. Some studies have shown that juvenile Acroporid corals were first dominated by nonhomologous adult Symbiodinium algae from clade A or D, and later by clade C algae, which had an adult homologous association. Conversely, Littleand Littman et al.found that Acroporid juvenile polyps, around one- month old, were able to acquire clade C Symbiodinium algae. Thus, corals can change their dominant symbiotic algae depending on their environment and growth stage. However, these previous studies have only shown molecular data of Symbiodinium clade within field corals. There were no studies comparing the increased rate of each Symbiodinium clade in juvenile polyps. The physiological properties of corals may be influenced by their dominant clade of endosymbiotic algae. Some studies have shown that clade D Symbiodinium algae are thermally tolerant and increase coral resistance to elevated sea surface temperatures. Baker et al.showed that in 1997, corals containing clade D Symbiodinium algae were unaffected by bleaching, while corals associated with clade C algae were severely bleached. Adult Acropora millepora corals have shown an increase in thermal tolerance, by 1�C1.5uC, after changing their dominant symbiont algae from clade C to clade D. On the other hand, it has been reported that juvenile Acropora tenuis polyps hosting clade C1 algae had greater thermal tolerances than those associated with clade D algae.