A high-throughput screening platform for enzymes active on mucin-type O-glycoproteins.

Mucin-type O-glycosylation is a post-translational modification present at the interface between cells where it has important roles in cellular communication. However, deciphering the function of O-glycoproteins and O-glycans can be challenging, especially as few enzymes are available for their assembly or selective degradation. Here, to address this deficiency, we developed a genetically encoded screening methodology for the discovery and engineering of the diverse classes of enzymes that act on O-glycoproteins. The method uses Escherichia coli that have been engineered to produce an O-glycosylated fluorescence resonance energy transfer probe that can be used to screen for O-glycopeptidase activity. Subsequent cleavage of the substrate by O-glycopeptidases provides a read-out of the glycosylation state of the probe, allowing the method to also be used to assay glycosidases and glycosyltransferases. We further show the potential of this methodology in the first ultrahigh-throughput-directed evolution of an O-glycopeptidase.

Multiblock Bottlebrush Nanofibers from Organic Electronic Materials.

Methods are described for the preparation of fiber-like nanomaterials that mimic the multilayer structure of organic electronic devices on individual polymer chains. By combining Cu(0) reversible-deactivation radical polymerization (RDRP) and ring-opening metathesis polymerization (ROMP), multiblock bottlebrush copolymers are synthesized from ordered sequences of organic semiconductors. Narrowly dispersed fibers are prepared from materials commonly used as the hole transport, electron transport, and host materials in organic electronics, with molecular weights exceeding 2 × 106 Da and dispersities as low as 1.12. Diblock nanofibers are then synthesized from pairs of semiconducting building blocks, giving nanostructures analogous to p- n junctions that exhibit the reversible electrochemistry of their individual parts. Finally, this strategy is used to construct nanofibers with the structure of phosphorescent organic light-emitting diodes (OLEDs) on single macromolecules, such that the photophysical properties of each component of an OLED can be independently observed. These multiblock nanofibers can be formed from arbitrary organic semiconductors without the need for crystallinity, selective solvation, or supramolecular interactions, providing powerful methods for the miniaturization of materials for organic devices.

Lessons learned when innovations go awry: a baseline description of a behavioral trial-the Enhancing Fitness in Older Overweight Veterans with Impaired Fasting Glucose study.

Individuals diagnosed with impaired glucose tolerance (i.e., prediabetes) are at increased risk for developing diabetes. We proposed a clinical trial with a novel adaptive randomization designed to examine the impact of a home-based physical activity (PA) counseling intervention on metabolic risk in prediabetic elders. This manuscript details the lessons learned relative to recruitment, study design, and implementation of a 12-month randomized controlled PA counseling trial. A detailed discussion on how we responded to unforeseen challenges is provided. A total of 302 older patients with prediabetes were randomly assigned to either PA counseling or usual care. A novel adaptive design that reallocated counseling intensity based on self-report of adherence to PA was initiated but revised when rates of non-response were lower than projected. This study presents baseline participant characteristics and discusses unwelcome adaptations to a highly innovative study design to increase PA and enhance glucose metabolism when the best-laid plans went awry.

Individual progress toward self-selected goals among older adults enrolled in a physical activity counseling intervention.

The purpose of this study was to examine what happens to goals over the course of a physical activity counseling trial in older veterans. At baseline, participants (N = 313) identified 1 health-related goal and 1 walking goal for their participation in the study and rated where they perceived themselves to be relative to that goal at the current time. They rated their current status on these same goals again at 6 and 12 mo. Growth-curve analyses were used to examine longitudinal change in perceived goal status. Although both the intervention and control groups demonstrated improvement in their perceived proximity to their health-related and walking goals (L = 1.19, p < .001), the rates of change were significantly greater in the intervention group (ß = -.30, p < .05). Our results demonstrate that this physical activity counseling intervention had a positive impact on self-selected goals over the course of the intervention.