Biocatalytic asymmetric aldol addition into unactivated ketones.

Enzymes are renowned for their catalytic efficiency and selectivity, but many classical transformations in organic synthesis have no biocatalytic counterpart. Aldolases are prodigious C-C bond-forming enzymes, but their reactivity has only been extended past activated carbonyl electrophiles in special cases. To probe the mechanistic origins of this limitation, we use a pair of aldolases whose activity is dependent on pyridoxal phosphate.

Efficient chemoenzymatic synthesis of α-aryl aldehydes as intermediates in C-C bond forming biocatalytic cascades.

Multi-enzyme biocatalytic cascades are emerging as practical routes for the synthesis of complex bioactive molecules. However, the relative sparsity of water-stable carbon electrophiles limits the synthetic complexity of molecules made from such cascades. Here, we develop a chemoenzymatic platform that leverages styrene oxide isomerase (SOI) to covert readily accessible aryl epoxides into α-aryl aldehydes through a Meinwald rearrangement.

Perceptions of SNAP and Stocking Standards: A Qualitative Study of California Small Food Store Owners and Managers.

The Supplemental Nutrition Assistance Program (SNAP) is critical to alleviating food insecurity, but low diet quality among program participants is a concern. Nutrition-related interventions have focused on SNAP-authorized food retailers, but the perspectives of small food store owners and managers have not been represented in national policy discussions. This study aimed to explore the opinions of store owners/managers of SNAP-authorized small food stores about their overall perceptions of the program and the stricter stocking standards previously proposed in 2016.

l-Threonine Transaldolase Activity Is Enabled by a Persistent Catalytic Intermediate.

l-Threonine transaldolases (lTTAs) are a poorly characterized class of pyridoxal-5'-phosphate (PLP) dependent enzymes responsible for the biosynthesis of diverse β-hydroxy amino acids. Here, we study the catalytic mechanism of ObiH, an lTTA essential for biosynthesis of the β-lactone natural product obafluorin. Heterologously expressed ObiH purifies as a mixture of chemical states including a catalytically inactive form of the PLP cofactor.

"It's a Feeling That One Is Not Worth Food": A Qualitative Study Exploring the Psychosocial Experience and Academic Consequences of Food Insecurity Among College Students.

Background: The issue of food insecurity is one of growing concern among institutions of higher learning in the United States. In addition to studies on the prevalence and risk factors, research is needed to better understand the mechanisms by which food insecurity affects students' health and well-being.

Objective: To critically explore the experience of food insecurity among college students and its impact on psychosocial health and academic performance.

Immediate Sequential Bilateral Pediatric Vitreoretinal Surgery: An International Multicenter Study.

Purpose: To determine the feasibility and safety of bilateral simultaneous vitreoretinal surgery in pediatric patients.

Design: International, multicenter, interventional, retrospective case series.

Participants: Patients 17 years of age or younger from 24 centers worldwide who underwent immediate sequential bilateral vitreoretinal surgery (ISBVS)-defined as vitrectomy, scleral buckle, or lensectomy using the vitreous cutter-performed in both eyes sequentially during the same anesthesia session.