Incubation of labeled uridine diphosphate glucose with an enzyme preparation from Rhizobium meliloti or Agrobacterium tumefaciens leads to the formation of a glucan which appears to be identical to the beta 1-2 cyclic glucan described by several workers. This conclusion is based on the molecular size, the formation of sophorose and higher homologs by partial acid hydrolysis, the liberation of only glucose by total acid hydrolysis, and the release of only 3,4,6-tri-O-methylglucose after methylation and hydrolysis. A snail intestinal juice enzyme was found to break down the glucan and its partial hydrolysis products. A beta-glucosidase from sweet almonds degraded sophorose but not the intact glucan.
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http://dx.doi.org/10.1016/0003-9861(85)90176-6 | DOI Listing |
J Am Chem Soc
January 2025
Molecular Synthesis Center, Key Laboratory of Marine Drugs of Ministry of Education, Shandong Key Laboratory of Glycoscience and Glycotherapeutics, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
2-Deoxy-β-glycosides are essential components of natural products and pharmaceuticals; however, the corresponding 2-deoxy-β-glycosidic bonds are challenging to chemically construct. Herein, we describe an efficient catalytic protocol for synthesizing 2-deoxy-β-glycosides via either IPrAuNTf-catalyzed activation of a unique 1,2--positioned C2--propargyl xanthate (OSPX) leaving group or (PhO)PAuNTf-catalyzed activation of a 1,2--C2--alkynylbenzoate (OABz) substituent of the corresponding thioglycosides. These activation processes trigger 1,2-alkyl/arylthio-migration glycosylation, enabling the synthesis of structurally diverse 2-deoxy-β-glycosides under mild reaction conditions.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2025
Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616.
The L-type Ca channel (Ca1.2) is essential for cardiac excitation-contraction coupling. To contribute to the inward Ca flux that drives Ca-induced-Ca-release, Ca1.
View Article and Find Full Text PDFPLoS One
January 2025
School of Social Research, Renmin University of China, Beijing, China.
The reform of rural collective property rights system is of great significance for protecting the collective asset rights and interests of villagers, activating rural resource elements, and achieving rural revitalization. This study is based on 284 village committee questionnaires and 7451 villager questionnaires from 10 provinces in China, and uses multi-layer linear regression models to explore the impact of the reform of rural collective property rights system on villagers' public participation. Research has found that:(1) the reform of rural collective property rights system that has been completed at the rural level can significantly enhance the public participation of villagers, including total participation (β = 0.
View Article and Find Full Text PDFEnviron Microbiol
January 2025
Faculty of Biology-Microbiology, University of Freiburg, Freiburg, Germany.
Bacterial degradation of ubiquitous and persistent steroids such as steroid hormones is important for their removal from the environment. Initial studies of steroid degradation in anaerobic bacteria suggested that ring-cleaving hydrolases are involved in oxygen-independent sterane skeleton degradation. However, the enzymes involved in ring A cleavage of the common intermediate androsta-1,4-diene-3,17-dione have remained unknown.
View Article and Find Full Text PDFJ Gerontol B Psychol Sci Soc Sci
January 2025
Herbert and Jacqueline Krieger Klein Alzheimer's Research Center, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA.
Objectives: The oldest old adults (90+) constitute the fastest growing demographic at highest dementia risk among older adults. Depression, a common risk factor, inherently presents with heterogeneous clinical manifestations. Here, we explored the associations of the predominant depression dimensions with cognition in the LifeAfter90 study.
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