ABSTRACT
In 1985, S. Sekine et al. successfully cloned and expressed the cDNA of salmon growth hormone (sGH) in Escherichia coli. Saito et al. also reported cloning and expression of eel GH cDNA in E. coli. This research allowed the application of recombinant fish GHs to fish aquaculture. Growth hormone (GH) is expected to not only promote the growth of fish, but also to increase the efficacy of feed, to decrease mortality, and to promote smoltification. Inclusion body formation is believed to be affected by the properties of the protein itself, the host cell, and the culture conditions. It has been reported that higher growth temperatures promote aggregation, but the effects of other culture conditions have not been elucidated. This chapter confirms that rsGH I inclusion body formation was promoted at higher culture temperatures, such as 37 C, at pH 6.6. It clarifies the major issues needed to be solved for production of recombinant proteins expressed in E. coli.
