The first step in the development of Helicobacter pylori pathogenicity is receptor-mediated adhesion to gastric epithelium. Adhesins of H. pylori not only enable colonisation of the epithelium, with BabA interacting with Lewis, but also interaction of lipopolysaccharide (LPS) with galectin-3 contributes to attachment of H. pylori to the host cells. Anti-adhesive compounds against H. pylori have been described, but specific analytical assays for pinpointing the interaction with BabA are limited. LPS-galectin-3 inhibitors have not been described until now. A sandwich ELISA with recombinant BabA-6K was developed to investigate the interaction of BabA with Lewis-HSA. Isothermal titration calorimetry gave thermodynamic information on the interaction between BabA, Lewis-HSA and anti-adhesive compounds. A highly esterified rhamnogalacturonan from Abelmoschus esculentus inhibited the adhesion of H. pylori to adherent gastric adenocarcinoma (AGS) cells (IC 550 μg/mL) and interacted with BabA (IC 17 μg/mL). Pectins with similar rhamnogalacturonan structure showed weak anti-adhesive activity. Highly branched rhamnogalacturonans with low uronic acid content and high degree of esterification are potent BabA inhibitors. BabA represents a promising target for the development of anti-adhesive drugs against H. pylori. The rhamnogalacturonan influenced also the binding affinity of H. pylori to recombinant galectin-3 in a concentration-dependent manner with an IC of 222 μg/mL. Similar effects were obtained with pectin from apple fruits, while pectins from other sources were inactive.
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http://dx.doi.org/10.1007/s00253-019-10234-1 | DOI Listing |
Nat Chem
January 2025
Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK.
Understanding the dynamics of membrane protein-ligand interactions within a native lipid bilayer is a major goal for drug discovery. Typically, cell-based assays are used, however, they are often blind to the effects of protein modifications. In this study, using the archetypal G protein-coupled receptor rhodopsin, we found that the receptor and its effectors can be released directly from retina rod disc membranes using infrared irradiation in a mass spectrometer.
View Article and Find Full Text PDFPhytomedicine
December 2024
Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100073, China. Electronic address:
Background: Adherence of Helicobacter pylori to the surface of the gastric mucosa is the initial and crucial step for its survival and colonization in the harsh conditions of the stomach. We had previously demonstrated that daphnetin has anti-adhesion effect.
Purpose: This study aims to explore the mechanisms of daphnetin to reduce H.
J Child Lang
January 2025
Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, Pisa, Italy.
To investigate how a high risk for infant neurological impairment affects the quality of infant verbal interactions, and in particular properties of infant-directed speech, spontaneous interactions between 14 mothers and their 4.5-month-old infants at high risk for neurological disorders (7 female) were recorded and acoustically compared with those of 14 dyads with typically developing infants (8 female). Mothers of at-risk infants had proportionally less voicing, and the proportion of voicing decreased with increasing severity of the infants' long-term outcome.
View Article and Find Full Text PDFBiometals
December 2024
Department of Chemistry, Baba Mastnath University, Asthal Bohar, Rohtak, 124021, India.
The Schiff base metal complexes containing the transition metal ions Co(II), Ni(II) and Cu(II) were synthesized using their nitrate and acetate salts. An octahedral environment encircling metal complexes has been demonstrated by the findings of multiple spectroscopic approaches that were employed to demonstrate the structure of the metal complexes. The Coats-Redfern method of thermal analysis was employed to carry out the kinetic and thermodynamic calculations.
View Article and Find Full Text PDFPsychol Med
December 2024
Unit for Mental Health Promotion, Research Center for Social Science & Medicine, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
Background: Schools are central places for adolescent social lives, which is a major factor greatly affecting adolescent mental health; school climate (i.e. quality of the school social environments) can be a proximal social determinant for adolescent mental health.
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