Klebsiella (nee Enterobacter) aerogenes is the first human gut commensal bacterium with a documented sensitivity to the pineal/gastrointestinal hormone melatonin. Exogenous melatonin specifically increases the size of macrocolonies on semisolid agar and synchronizes the circadian clock of K. aerogenes in a concentration dependent manner. However, the mechanisms driving these phenomena are unknown. In this study, we applied RNA sequencing to identify melatonin sensitive transcripts during culture maturation. This work demonstrates that the majority of melatonin sensitive genes are growth stage specific. Melatonin exposure induced differential gene expression of 81 transcripts during exponential growth and 30 during early stationary phase. This indole molecule affects genes related to biofilm formation, fimbria biogenesis, transcriptional regulators, carbohydrate transport and metabolism, phosphotransferase systems (PTS), stress response, metal ion binding and transport. Differential expression of biofilm and fimbria-related genes may be responsible for the observed differences in macrocolony area. These data suggest that melatonin enhances Klebsiella aerogenes host colonization.
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http://dx.doi.org/10.1016/j.ygeno.2022.110321 | DOI Listing |
Environ Microbiol
January 2025
Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
The Hepatincolaceae (Alphaproteobacteria) are a group of bacteria that inhabit the gut of arthropods and other ecdysozoans, associating extracellularly with microvilli. Previous phylogenetic studies, primarily single-gene analyses, suggested their relationship to the Holosporales, which includes intracellular bacteria in protist hosts. However, the genomics of Hepatincolaceae is still in its early stages.
View Article and Find Full Text PDFArch Biochem Biophys
January 2025
Department of Urology, Affiliated Haikou Hospital of Central South University Xiangya Medical School, Central South University, Changsha, Hunan, 410011, China; Department of Urology, the Third People's Hospital of Haikou, Hainan, 570100, China. Electronic address:
Benign prostatic hyperplasia (BPH) is a prevalent condition associated with male lower urinary tract symptoms (LUTS) and is influenced by metabolic syndrome (MetS) and gut microbiota. Akkermansia muciniphila (AKK) is a gut commensal that has emerged as a potential modulator of metabolic health and inflammatory conditions. This study investigated the correlation between Akkermansia abundance and BPH severity and metabolic indices in fecal and serum samples from BPH patients and healthy donors using 16S rRNA sequencing and metabolic profiling.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Critical Care Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, 510280, China.
Older individuals experience increased susceptibility and mortality to bacterial infections, but the underlying etiology remains unclear. Herein, it is shown that aging-associated reduction of commensal Parabacteroides goldsteinii (P. goldsteinii) in both aged mice and humans critically contributes to worse outcomes of bacterial infection.
View Article and Find Full Text PDFCurr Gastroenterol Rep
December 2025
Division of Pulmonary, Critical Care, and Sleep Medicine, Medical College of Wisconsin, 8701 West Watertown Plank Road, 8th Floor: HUB for Collaborative Medicine, Milwaukee, WI, 53226, USA.
Purpose Of Review: The purpose of this narrative review is to describe the mechanisms for gut dysfunction during critical illness, outline hypotheses of gut-derived inflammation, and identify nutrition and non-nutritional therapies that have direct and indirect effects on preserving both epithelial barrier function and gut microbiota during critical illness.
Recent Findings: Clinical and animal model studies have demonstrated that critical illness pathophysiology and interventions breach epithelial barrier function and convert a normally commensal gut microbiome into a pathobiome. As a result, the gut has been postulated to be the "motor" of critical illness and numerous hypotheses have been put forward to explain how it contributes to systemic inflammation and drives multiple organ failure.
Microbiol Spectr
January 2025
Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, Colorado, USA.
Unlabelled: Studies have suggested that phytochemicals in green tea have systemic anti-inflammatory and neuroprotective effects. However, the mechanisms behind these effects are poorly understood, possibly due to the differential metabolism of phytochemicals resulting from variations in gut microbiome composition. To unravel this complex relationship, our team utilized a novel combined microbiome analysis and metabolomics approach applied to low complexity microbiome (LCM) and human colonized (HU) gnotobiotic mice treated with an acute dose of powdered matcha green tea.
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