A force sensor that converts fluorescence signal into force measurement utilizing short looped DNA.

A force sensor concept is presented where fluorescence signal is converted into force information via single-molecule Förster resonance energy transfer (smFRET). The basic design of the sensor is a ~100 base pair (bp) long double stranded DNA (dsDNA) that is restricted to a looped conformation by a nucleic acid secondary structure (NAS) that bridges its ends. The looped dsDNA generates a tension across the NAS and unfolds it when the tension is high enough.

A practical guide to studying G-quadruplex structures using single-molecule FRET.

In this article, we summarize the knowledge and best practices learned from bulk and single-molecule measurements to address some of the frequently experienced difficulties in single-molecule Förster resonance energy transfer (smFRET) measurements on G-quadruplex (GQ) structures. The number of studies that use smFRET to investigate the structure, function, dynamics, and interactions of GQ structures has grown significantly in the last few years, with new applications already in sight. However, a number of challenges need to be overcome before reliable and reproducible smFRET data can be obtained in measurements that include GQ.

A Comparative Study of G-Quadruplex Unfolding and DNA Reeling Activities of Human RECQ5 Helicase.

RECQ5 is one of five members of the RecQ family of helicases in humans, which include RECQ1, Bloom (BLM), Werner (WRN), RECQ4, and RECQ5. Both WRN and BLM have been shown to resolve G-quadruplex (GQ) structures. Deficiencies in unfolding GQ are known to result in DNA breaks and genomic instability, which are prominent in Werner and Bloom syndromes.

Infrarenal origin of the superior mesenteric artery: implications in endovascular repair of abdominal aortic aneurysm.

Endovascular aneurysm repair (EVAR) has become the preferred modality for the treatment of infrarenal abdominal aortic aneurysms (AAAs). A variety of anatomic factors must be considered when planning EVAR, including the relationship of the visceral arteries to the aneurysmal segment of the aorta. This report describes 2 patients with infrarenal AAA in whom the superior mesenteric artery was the most caudal visceral vessel, originating inferior to the renal arteries.