sentence: Many of the P. donghaiense photosynthesis genes were highly expressed and up-regulated at T123 , e.g ., carbonic anhydrase , a crucial enzyme for inorganic carbon uptake being up-regulated by 101-folds , and Ribulose-1 , 5-bisphosphate carboxylase / oxygenase , an essential enzyme for carbon fixation , up-regulated by twofolds ( Figure 2Civ , 3B and Supplementary Dataset 4 ) .