The present application provides genetically modified yeast cell comprising an active succinate fermentation pathway, as well as methods of using these cells to produce succinate.

The present invention provides a genetically engineered pantoic acid-producing strain having or having an enhanced NADH-dependent acetohydroxy acid reductoisomerase, a method for producing the strain, a method for producing D-pantoic acid using the strain, and use thereof in production of D-pantoic acid.

Examination of a test sample to determine the presence or quantity of succination of proteins is described. Examination can be via protein hydrolysis in total succination determination or via enzymatic digestion of isolated proteins and determination of the presence or quantity of modified peptides. The methods can be utilized for determination of excessive succination of lymph system proteins, which can be utilized in prevention or early detection of lymphopenia. Methods can be utilized for test samples of subjects under treatment with dimethyl fumarate suffering from multiple sclerosis. Methods can be utilized as a determination that treatment of the subject with DMF should be slowed or stopped.

The present disclosure relates to a genetically modified microorganism satisfying some of predetermined conditions. The predetermined conditions include: (I) succinate dehydrogenase activity or fumarate reductase activity being reduced or inactivated relative to a wild-type microorganism; (II) lactate dehydrogenase activity being reduced or inactivated relative to the wild-type microorganism; (III) the genetically modified microorganism having modified phosphoenolpyruvate carboxylase activity showing resistance to feedback inhibition by aspartic acid in wild-type phosphoenolpyruvate carboxylase activity, or exogenous phosphoenolpyruvate carboxylase activity having higher resistance to feedback inhibition by aspartic acid than that of the wild-type phosphoenolpyruvate carboxylase activity shown by the wild-type microorganism; and (IV) pyruvate:quinone oxidoreductase being reduced or inactivated relative to the wild-type microorganism.