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This study investigated the structure and functional properties including in vitro hypoglycemic, antioxidant, and immunoenhancing activities of water-soluble mulberry leaf polysaccharides (MLP) from Morus abla L. cv. Longsang 1. The results showed that the yield of MLP was (16.16 ± 0.30) mg/g with sugar content of (57.16 ± 4.00)% and uronic acid content of (30.97 ± 2.06)%. The molecular mass distribution of MLP, as measured by gel permeation chromatography (GPC), was mainly concentrated at 21.74 kDa. Monosaccharide composition analysis showed that MLP mainly contained glucose, rhamnose, galactose, xylose, uronic acid (including glucuronic acid, galacturonic acid and mannuronic acid), and mannose, with a molar ratio of 59.17:22.31:10.44:2.65:2.28:1.07. Fourier transform infrared (FT-IR) spectroscopy and atomic force microscopy (AFM) indicated that MLP was a pyranose with intertwined branches and helical aggregation. MLP inhibited α-glucosidase and α-amylase with concentration for 50% of maximal effect (EC50) of 1.81 mg/mL and 2.91 mg/mL, respectively, and its inhibitory activities were 49.17% and 37.80% as high as those of acarbose, respectively. MLP scavenged 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2, 2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical, and hydroxyl radical with EC50 of 0.54, 0.60 and 1.77 mg/mL, respectively, and the radical scavenging capacities were 4.77%, 38.03%, and 19.94% as high as those of ascorbic acid, respectively. When applied to RAW264.7 mouse macrophages, MLP increased the secretion of the proinflammatory cytokines NO, tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β and enhanced macrophage proliferation and phagocytosis, thereby exerting an immunoenhancing effect. The research results can provide experimental data for the application and functional evaluation of mulberry leaves grown in cold regions.

PINA is a novel ATPase and DNA helicase highly conserved in Archaea, the third domain of life. The PINA from Sulfolobus islandicus (SisPINA) forms a hexameric ring in crystal and solution. The protein is able to promote Holliday junction (HJ) migration and physically and functionally interacts with Hjc, the HJ specific endonuclease. Here, we show that SisPINA has direct physical interaction with Hjm (Hel308a), a helicase presumably targeting replication forks. In vitro biochemical analysis revealed that Hjm, Hjc, and SisPINA are able to coordinate HJ migration and cleavage in a concerted way. Deletion of the carboxyl 13 amino acid residues impaired the interaction between SisPINA and Hjm. Crystal structure analysis showed that the carboxyl 70 amino acid residues fold into a type II KH domain which, in other proteins, functions in binding RNA or ssDNA. The KH domain not only mediates the interactions of PINA with Hjm and Hjc but also regulates the hexameric assembly of PINA. Our results collectively suggest that SisPINA, Hjm and Hjc work together to function in replication fork regression, HJ formation and HJ cleavage.

Service robots have become a topic of interest for tourism and hospitality researchers and practitioners. The success of service robot adoption lies in the effectiveness of tourist–robot interaction. There has been less interest in the performance of tourist–robot interaction, with research related to tourist engagement being particularly scarce. Drawing on the theoretical perspective of relationships, this article examines the impact of tourist–robot interaction on tourist engagement in the hospitality context. A mixed-methods approach is adopted, utilizing grounded theory and structural equation modeling. The findings reveal two types of tourist–robot interaction, emotional (fun and playfulness) and instrumental (convenience and ease of use). Tourist–robot emotional interactions influence tourist engagement by enhancing tourists' needs satisfaction, tourist emotion, and social bonds with robots. It was found that tourist–robot instrumental interaction positively affects tourist engagement through needs satisfaction and tourist emotion but not social bonds. The findings extend our understanding of human–robot interaction and customer engagement. [ABSTRACT FROM AUTHOR]