ABSTRACT
Previous research, defining spatial control of inositol phosphate biosynthesis in the developing brain of CBA (normal) and CT [curly tail (ct-CT) and straight tail (st-CT)] mutant mice implicated a role for 1l-myo-inositol 1-phosphate synthase (MIP) in normal functioning of the central nervous system. Biochemical research indicated that MIP enzymatic activity, conversion of glucose 6-phosphate into inositol phosphate, is highest in the cerebellum of ct-CT and lowest in st-CT, when compared to that of CBA mice.Here, we utilized microscopic and biochemical investigations to analyze and extend previous findings of MIP expression in the cerebellum. Results of this research indicated that MIP expression correlates, well, with its enzymatic activity in the cerebellum of CBA and CT mutantmice. Statistical analyses of fluorescent micrographs detected a significant difference in fluorescence intensity between MIP from ct-CT, st-CT, and CBA mice.These data support vitallinks between inositol phosphate biosynthesis, MIP expression, and normal functioning of the cerebellum. Moreover, published data, identifying significant behavioral differences in the CT mutant, as well as data linking motor and non-motor cerebellar functions to abnormal levels of inositol, support the conclusion that aspects of normal cerebellar functions require temporal and spatial control of inositol phosphate biosynthesis, MIP expression.
ABSTRACT
Glucaric acid, a high value-added organic acid, is widely used in food, pharmaceutical and chemical industries. For microbial production of glucaric acid in Saccharomyces cerevisiae, we constructed a synthetic glucaric acid biosynthetic pathway by coexpressing the genes encoding myo-inositol oxygenase from mice and uronate dehydrogenase from Pseudomonas putida. Moreover, myo-inositol-1-phosphate synthase was identified as a rate-limiting enzyme in glucaric acid pathway and was upregulated, resulting in the production of glucaric acid of (107.51±10.87) mg/L, a 2.8-fold increase compared to the parent strain. Then, by repressing the activity of phosphofructokinase, the concentration of glucaric acid further increased to (230.22±10.75) mg/L. The strategy could be further used to construct cell factories for glucaric acid production.