Corn (Zea mays L.) grown on sandy Atlantic Coastal Plain soils is often unresponsive to applications of K fertilizer. As part of a field study on the response of irrigated, intensively managed corn to K applications, we characterized four representative Hapludults from the Delaware Coastal Plain and evaluated their K status. The soils were generally quite sandy with maximum clay contents of 11....

To investigate the mechanism by which cell surface receptors activate heterotrimeric G proteins, we applied a scanning mutagenesis approach to the carboxyl-terminal 40% of as (residues 236–394) to identify residues that play a role in receptormediated activation. We identified four regions of sequence in which mutations significantly impaired receptor-dependent stimulation of cAMP synthesis in ...