In 2001, it was observed that the cardia region of the lumen of the stomach remained highly acidic after a meal and escaped the buffering effect of the food. This phenomenon was termed the acid pocket and is thought to explain why reflux symptoms occur after meals despite the buffering effect of food. This review describes the discovery of the acid pocket and our progress in understanding the intragastric physiology producing it, its exaggeration in hiatus hernia and role in reflux disease. The recent discovery that the acid pocket is attenuated in the Helicobacter pylori-infected population and the significance of this to the negative association between H. pylori and reflux disease and its complications is also addressed. Finally, the role of the acid pocket in providing protection from potentially pathogenic ingested microorganisms is discussed.
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http://dx.doi.org/10.1097/MCG.0000000000000939 | DOI Listing |
Nat Commun
January 2025
Laboratory of Structural Biochemistry, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany.
Many bacteriophages modulate host transcription to favor expression of their own genomes. Phage satellite P4 polarity suppression protein, Psu, a building block of the viral capsid, inhibits hexameric transcription termination factor, ρ, by presently unknown mechanisms. Our cryogenic electron microscopy structures of ρ-Psu complexes show that Psu dimers clamp two inactive, open ρ rings and promote their expansion to higher-oligomeric states.
View Article and Find Full Text PDFBioorg Chem
January 2025
School of Biotechnology and Key Laboratory of Industrial Biotechnology of Education, School of Biotechnology, Jiangnan University, Wuxi 214122 China. Electronic address:
Achieving enzyme catalysis at high substrate concentrations is a substantial challenge in industrial biocatalysis, and the role of glycosylation in post-translational modifications that modulate enzyme substrate inhibition remains poorly understood. This study provides insights into the role of N-glycosylation in substrate inhibition by comparing the catalytic properties of d-lactonohydrolase (d-Lac) derived from Fusarium moniliforme expressed in prokaryotic and eukaryotic hosts. Experimental evidence indicates that recombinant d-Lac expressed in Pichia pastoris (PpLac-WT) exhibits higher hydrolysis rates at a substrate concentration of 400 g/L, with reduced substrate inhibition and enhanced stability compared to the recombinant d-Lac expressed in Escherichia coli (EcLac-WT).
View Article and Find Full Text PDFAnal Chem
January 2025
Guangdong Provincial Key Laboratory of Food Quality and Safety, South China Agricultural University, Guangzhou 510642, China.
The rapid, sensitive, and accurate detection of paralytic shellfish toxins (PSTs), such as saxitoxin (STX), is critical for protecting human health due to the frequent occurrence of toxic red tides. In this work, to address the low affinity of traditional mouse monoclonal antibodies (m-mAbs), rabbit monoclonal antibodies (r-mAbs) against STX were produced by a single B-cell sorting culture and a cross-selection strategy. The r-mAbs showed 100-fold improvement in sensitivity (IC = 0.
View Article and Find Full Text PDFFertil Steril
January 2025
Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104 USA. Electronic address:
Background: Thrombin prefers substrates carrying Arg at the site of cleavage (P1) because of the presence of D189 in the primary specificity (S1) pocket but can also cleave substrates carrying Phe at P1. The structural basis of this property is unknown.
Objective: Solve the X-ray structure of thrombin bound to a ligand carrying Phe at P1 and investigate the effects of replacing D189.
Nucleic Acids Res
January 2025
Advanced Analysis Data Center, Korea Institute of Science and Technology, Hwarang-ro 14-5, Seongbuk-gu, Seoul 02792, Republic of Korea.
Riboswitches are RNAs that recognize ligands and regulate gene expression. They are typically located in the untranslated region of bacterial messenger RNA and consist of an aptamer and an expression platform. In this study, we examine the folding pathway of the Vc2 (Vibrio cholerae) riboswitch aptamer domain, which targets the bacterial secondary messenger cyclic-di-GMP.
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