Effect of nature exposure on perceived and physiologic stress: A systematic review.

Objective: The purpose of this systematic review is to evaluate the effect nature exposure has on stress as measured by physiologic markers and self-report.

Design: Researchers searched PubMed and JSTOR. Randomized control trials and cross-sectional studies were included if they met the following criteria: 1) included a clinical cohort and controls, and the intervention was nature exposure, either real or simulated; (2) utilized measurements of sympathetic activity or perceived stress; (3) study population consisted of greater than thirty male and female volunteers.

Control of Hexamerization, Assembly, and Excluded Strand Specificity for the Sulfolobus solfataricus MCM Helicase.

A growing body of evidence supports a steric exclusion and wrapping model for DNA unwinding in which hexameric helicases interact with the excluded single-stranded DNA (ssDNA) in addition to the encircled strand. Interactions with the excluded ssDNA have been shown to be mediated primarily by electrostatic interactions, but base stacking with surface-exposed tyrosine residues is an alternative hypothesis. Here, we mutated several external tyrosine and positively charged residues from full-length Sulfolobus solfataricus MCM along the proposed path of excluded strand binding and assessed their impact on DNA unwinding.