Similarly, the motor protein dynein (DynII2a) was also much lower in N36 barramundi than in N22. The expression of these related genes suggests that in response to rearing at 22 °C, extensive remodeling of the cytoskeletal elements is necessary towards the adaptation of barramundi to cooler conditions, or that lower temperatures are damaging to these molecules and that new cytoskeletal proteins are required to replace them ( Buckley et al., 2006). Osmotic stress in cells is known to induce remodeling of the cytoskeleton in order to modify cell volume and cytoskeletal proteins have previously been shown to be regulated
in teleosts in response to temperature stress ( Ju et al., 2002, Podrabsky and Somero, 2004 and Sarmiento et al., 2000). Both of the above mentioned theories are credited by the expression Obeticholic Acid in vivo of the “response to stress”
genes, namely heat shock protein alpha crystalline related b2 (Hspb2) and heat shock 70.3 kDa protein like (Hsp70.3), which were both shown to exhibit lower expression BAY 80-6946 in vivo in N36 barramundi compared with N22 ( Fig. 3). Small heat shock proteins (such as Hspb2) are known to play important roles in the prevention of diseased states and in promoting resistance to environmental stressors. In Danio rerio, small heat shock proteins have been shown to express during embryonic development and in response to mild heat shocks ( Elicker and Hutson, 2007). Small heat shock proteins have also been thought to protect cytoskeletal proteins in the muscle ( Nakagawa et al., 2001) while the larger Hsp70.3 is a known responder to temperature stress with a particular focus on molecular chaperoning ( Buckley et al., 2006). The expression Clomifene pattern of both heat shock proteins (Hsp’s) fits with the proposed theory that an increase in microtubule genes (Tubb4b, Tubb2b and Tuba) and the motor protein DynnII2a demonstrates an adaptive response in northern barramundi towards coping
with cooler temperatures through some form of cytoskeletal remodeling. Through an analysis of genes from the “endopeptidase inhibitor activity” GO category, 3 complement component genes; complement component 3-like isoform 1 precursor (C3 9 of 9), complement component 3-like precursor (C3 8 of 9) and predicted compliment C3 (C3 2 of 9), all showed a significant decrease in expression within southern barramundi reared at 36 °C in comparison to northern barramundi reared at 36 °C. In fish, the complement system is one of the main immune responses and causes lysis of target cells and the activation of phagocytosis (Boshra et al., 2006, Claire et al., 2002 and Tort et al., 2004). The depression of all three C3 related genes is suggestive of an immune suppression in cool adapted southern fish exposed to warmer rearing temperatures in comparison to warm adapted northern fish.