Quorum-sensing (QS) systems allow organisms, such as the pathogen Pseudomonas aeruginosa, to link gene expression with their population density and the diffusion and flow characteristics of their environment. The leading hypotheses about QS systems' biological functions necessitate that QS-controlled gene expression be suppressed until a threshold culture density (the quorum) is reached. Despite a detailed understanding of QS in P. aeruginosa, known regulatory elements do not fully explain how the quorum threshold for gene activation is produced. Here we investigated the mechanism with a screening approach that used random gene activation. These experiments uncovered a regulator without close homologs in other species that produces the quorum expression threshold. Expression of this regulator (named QteE) reduces LasR protein stability without affecting LasR transcription or translation. QteE also independently reduces RhlR levels. Because QteE can block QS when signal levels are high, it could provide a mechanism for individual cells to exert autonomous control over their QS regulons. This unique regulator governs two central QS control points in P. aeruginosa and shapes the expression pattern thought fundamental to the biological functions of QS.
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http://dx.doi.org/10.1073/pnas.0908511107 | DOI Listing |
J Transl Med
January 2025
Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University, Tongji University School of Medicine, Shanghai, 200065, China.
Background: Ferroptosis and immune responses are critical pathological events in spinal cord injury (SCI), whereas relative molecular and cellular mechanisms remain unclear.
Methods: Micro-array datasets (GSE45006, GSE69334), RNA sequencing (RNA-seq) dataset (GSE151371), spatial transcriptome datasets (GSE214349, GSE184369), and single cell RNA sequencing (scRNA-seq) datasets (GSE162610, GSE226286) were available from the Gene Expression Omnibus (GEO) database. Through weighted gene co-expression network analysis and differential expression analysis in GSE45006, we identified differentially expressed time- and immune-related genes (DETIRGs) associated with chronic SCI and differentially expressed ferroptosis- and immune-related genes (DEFIRGs), which were validated in GSE151371.
BMC Med Res Methodol
January 2025
Department of Women's and Children's Health - Obstetric & Reproductive Health Research, Uppsala University, Uppsala, 751 85, Sweden.
Background: Peripartum depression is a common but potentially debilitating pregnancy complication. Mobile applications can be used to collect data throughout the pregnancy and postpartum period to improve understanding of early risk indicators.
Aim: This study aimed to improve understanding of why women drop out of a peripartum depression mHealth study, and how we can improve the app design.
BMC Microbiol
January 2025
The Marine Science Institute, College of Science, University of the Philippines Diliman, Quezon City, Philippines.
Background: The observed growth variability of different aquaculture species in captivity hinders its large-scale production. For the sandfish Holothuria scabra, a tropical sea cucumber species, there is a scarcity of information on its intestinal microbiota in relation to host growth, which could provide insights into the processes that affect growth and identify microorganisms with probiotic or biochemical potential that could improve current production strategies. To address this gap, this study used 16 S rRNA amplicon sequencing to characterize differences in gut and fecal microbiota among large and small juveniles reared in floating ocean nurseries.
View Article and Find Full Text PDFJ Med Ethics
January 2025
Department of Biology, Stanford University, Stanford, California, USA
In a recent article, Haining outline several ethical and regulatory considerations for polygenic risk scores (PRSs), which may expand current embryonic screening to include polygenic diseases and non-disease traits. I argue in this response that the authors overlook a few crucial issues that nations should address. For adult-onset diseases, regulations must not only account for predictive accuracy of PRSs but also establish the precise circumstances that warrant testing-such as a disease's severity and the average age at which symptoms manifest.
View Article and Find Full Text PDFBioorg Chem
January 2025
National Center for Screening New Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, PR China. Electronic address:
Two cyclic octadepsipeptides, microascusins A and B (1 and 2), were identified from the marine sponge-associated Microascus croci IMB19-064 co-cultivated with Escherichia coli. Their structures and conformations in solution were determined by comprehensive spectroscopic data analysis. The absolute configurations of amino and hydroxy acids were determined by the advanced Marfey's and O-Marfey's methods, respectively, as well as chiral-phase HPLC analysis.
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