The anti-S2 peptides, the stabilizer and destabilizer, were designed to target myosin sub-fragment 2 (S2) in muscle. When the peptides are coupled to a heart-targeting molecule, they can reach the cardiomyocytes and interfere with cardiac muscle contraction. Monoclonal antibodies, MF20 and MF30, are also known to interact with light meromyosin and S2 respectively. The MF30 antibody compared to anti-S2 peptides and the MF20 antibody is used as a control to test the central hypothesis that: Both the anti-S2 peptides and antibodies bind to myosin S2 with high affinity, compete with MyBPC, and possibly interact with titin, in which case the anti-S2 peptides have further impact on myosin helicity and reach the heart with the aid of tannic acid to modulate cardiomyocytes' contraction in live mice. In this research, the effects of anti-S2 peptides and antibodies on myosin S2 were studied at the molecular and tissue levels. The anti-myosin binding mechanism to whole myosin was determined based on total internal reflectance fluorescence spectroscopy (TIRFS), and a modified cuvette was utilized to accommodate this experiment. The binding graphs indicated the cooperative binding of the peptides and antibodies with high affinity to myosin. Anti-myosin peptides and antibodies competition with Myosin Binding Protein C …

In this dissertation I am using M. truncatula as a model legume that forms indeterminate nodules with rhizobia under limited nitrogen conditions. I take advantage of an M. truncatula Tnt1 mutant population that provides a useful resource to uncover and characterize novel genes. Here, I focused on several objectives. First, I carried out forward and reverse genetic screening of M. truncatula Tnt1 mutant populations to uncover novel genes involved in symbiotic nitrogen fixation. Second, I focused on reverse genetic screening of two genes, identified as encoding blue copper proteins, and characterization of their mutants' potential phenotypes. Third, I further characterized a nodule essential gene, M. truncatula vacuolar iron transporter like 8 (MtVTL8), which encodes a nodule specific iron transporter. I characterized the expression pattern, expression localization and function of MtVTL8. Additionally, I characterized several residues predicted to be essential to function using a model based on the known crystal structure of Eucalyptus grandis vacuolar iron transporter 1 (EgVIT1), a homologous protein to MtVTL8. I identified several potential essential residues of the MtVTL8 protein, mutagenized them, and through complementation experiments in planta and in yeast assessed functionality of the resulting protein. This helped us to better understand the potential mechanism by …