The Handbook of Aging and Cognition by F. I. M. Craik and T. A. Salthouse,eds

Animal assisted activity (AAA) programs offer widespread physiological, social, and emotional benefits to recipient populations, particularly older adults. While AAA is common in nursing homes, it is less common in retirement residences where individuals are often suffering from the stress of relocating and transitioning to a more dependent lifestyle. PAWSitive Visits (PV) is a weekly AAA visitation program conducted in a group-setting at a Midwestern retirement residence that brings an array of domestic and exotic animal species for the residents to interact with. PV strives to provide educational opportunities for the residents, facilitating their social engagement, eliciting memories of previously owned pets, and offering intergenerational activities. It also provides meaningful learning experiences for students (e.g., nursing and veterinary medical students) who affiliate with the program. The conceptual model for PV is the threefold notion of attachment, reciprocity, and unconditional acceptance that animals offer older adults. PV is a unique and successful program, coordinated in a manner that ensures the health and safety of both animal and human counterparts, while providing residents with experiences that enhance their well-being.     

A peptide motif that recognizes A.T tracts in DNA.

The DAT1 gene of Saccharomyces cerevisiae encodes a DNA binding protein that specifically interacts with nonalternating oligo(A).oligo(T) tracts (A.T tracts). Deletion analysis of DAT1 coding information showed that the amino-terminal 36 residues are sufficient for specific DNA binding activity. Furthermore, a 35-residue synthetic peptide corresponding to amino acids 2-36 bound to A.T tracts with an equilibrium dissociation constant of 4 x 10(-10) M. Within this region the pentad Gly-Arg-Lys-Pro-Gly is repeated three times. Mutational analysis revealed that the Arg side chains are required for high-affinity binding, whereas the other pentad side chains are dispensable. Chemical interference experiments showed that the DAT1 protein interacts with the minor groove of the double helix. The data suggest that the pentad arginines interact in a cooperative manner with a repeated minor groove feature of A.T tract DNA to achieve high-affinity recognition. Amino acid similarities with other DNA binding proteins suggest that the DAT1 protein pentad represents a specialized example of a widespread motif used by proteins to recognize A.T base pairs.