The formal asymmetric and stereodivergent enzymatic reduction of α-angelica lactone to both enantiomers of γ-valerolactone was achieved in a one-pot cascade by uniting the promiscuous stereoselective isomerization activity of Old Yellow Enzymes with their native reductase activity. In addition to running the cascade with one enzyme for each catalytic step, a bifunctional isomerase-reductase biocatalyst was designed by fusing two Old Yellow Enzymes, thereby generating an unprecedented case of an artificial enzyme catalyzing the reduction of nonactivated C=C bonds to access (R)-valerolactone in overall 41 % conversion and up to 91 % ee. The enzyme BfOYE4 could be used as single biocatalyst for both steps and delivered (S)-valerolactone in up to 84 % ee and 41 % overall conversion. The reducing equivalents were provided by a nicotinamide recycling system based on formate and formate dehydrogenase, added in a second step. This enzymatic system provides an asymmetric route to valuable chiral building blocks from an abundant bio-based chemical.
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http://dx.doi.org/10.1002/cbic.202300146 | DOI Listing |
Elife
January 2025
Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, United States.
Sensory experience during developmental critical periods has lifelong consequences for circuit function and behavior, but the molecular and cellular mechanisms through which experience causes these changes are not well understood. The antennal lobe houses synapses between olfactory sensory neurons (OSNs) and downstream projection neurons (PNs) in stereotyped glomeruli. Many glomeruli exhibit structural plasticity in response to early-life odor exposure, indicating a general sensitivity of the fly olfactory circuitry to early sensory experience.
View Article and Find Full Text PDFACS Biomater Sci Eng
January 2025
Nano 2 Micro Material Design Lab, Department of Chemical Engineering and Technology, IIT (BHU), Varanasi 221005, India.
Herein, fluorescent calcium carbonate nanoclusters encapsulated with methotrexate (Mtx) and surface functionalized with chitosan (25 nm) (@Calmat) have been developed for the imaging and treatment of triple-negative breast cancer (TNBC). These biocompatible, pH-sensitive nanoparticles demonstrate significant potential for targeted therapy and diagnostic applications. The efficacy of nanoparticles (NPs) was evaluated in MDA-MB-231 TNBC cell lines.
View Article and Find Full Text PDFJ Prim Care Community Health
January 2025
University of California, Davis, Division of Hospital Medicine, Sacramento, CA, USA.
Introduction: Nadezhda Clinic is a free student-run health clinic that provides culturally sensitive primary care services to the underserved Russian-speaking population of the greater Sacramento area. At the onset of the COVID-19 pandemic, the clinic suspended in-person services and solely offered telemedicine visits. Most patients were hesitant to utilize telemedicine due to poor technological literacy, privacy concerns, and a preference for in-person care.
View Article and Find Full Text PDFJAMA Netw Open
January 2025
S-SPIRE Center, Department of Surgery, Stanford University School of Medicine, Stanford, California.
Importance: Transportation insecurity and lack of social support are 2 understudied social determinants of health that contribute to excess morbidity, mortality, and acute health care utilization. However, whether and how these social determinants of health are associated with cancer screening has not been determined and has implications for preventive care.
Objective: To determine whether transportation insecurity or social support are associated with screening adherence for colorectal, breast, and cervical cancer.
Chem Commun (Camb)
January 2025
Chemistry Division, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
This review discusses the properties of strongly oxidizing radicals in organic and aqueous media and highlights the challenges in obtaining accurate values of their reduction potentials. Transient redox equilibrium methods based on the use of strong photooxidants or initiated by pulse radiolysis are shown to provide versatile approaches for decoupling electron transfer reactions from follow-up reactivity of unstable radical species, resulting in accurate values of reduction potentials of very positive couples, including some solvent radical cations. We also show that correlations of reduction potentials with Hammett ∑+p parameters, as well as gas phase ionization potentials, can be used to estimate the redox properties of unknown couples within a homologous series of compounds.
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