Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium that replicates in the cytosol of host cells. Although several protein antigens have been characterized and cloned, little information exists regarding the polysaccharide antigen of this bacterium. In this study, we identified and characterized a novel antigen defined by a monoclonal antibody (MAb), NT19, against O. tsutsugamushi. Immunofluorescence microscopic studies showed that the NT19 antigen is released from the bacteria in the cytosol of host cells forming aggregates with bacteria. Immunoblot analysis showed that MAb NT19 recognized a strong band with a molecular mass of 20 kDa that was resistant to proteinase K digestion and sensitive to periodate oxidation, suggesting that the NT19 antigen is a polysaccharide. The function of this polysaccharide is not known, but considering its distribution within a bacterial microcolony, it is suspected to be involved in forming a biofilm-like structure within host cells.
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http://dx.doi.org/10.1111/j.1574-6968.2009.01663.x | DOI Listing |
Arch Toxicol
December 2024
Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
Systemic bile acid homeostasis plays an important role in human health. In this study, a physiologically based kinetic (PBK) model that includes microbial bile acid deconjugation and intestinal bile acid reuptake via the apical sodium-dependent bile acid transporter (ASBT) was applied to predict the systemic plasma bile acid concentrations in human upon oral treatment with the antibiotic tobramycin. Tobramycin was previously shown to inhibit intestinal deconjugation and reuptake of bile acids and to affect bile acid homeostasis upon oral exposure of rats.
View Article and Find Full Text PDFMalays J Pathol
December 2024
University Tunku Abdul Rahman, Faculty of Medicine and Health Sciences, Cheras 43000 Kajang, Selangor, Malaysia.
Conventionally, megakaryocytes (MKs) are regarded as platelet-producing cells and their platelet-related functions in haemostasis have been well documented. However, it is increasingly evident that MKs have functions beyond platelet production. Convincing findings suggest that MKs are active participants in immunity and infections.
View Article and Find Full Text PDFVirol J
December 2024
Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China.
PEDV is a highly contagious enteric pathogen that can cause severe diarrhea and death in neonatal pigs. Despite extensive research, the molecular mechanisms of host's response to PEDV infection remain unclear. In this study, differentially expressed genes (DEGs), time-specific coexpression modules, and key regulatory genes associated with PEDV infection were identified.
View Article and Find Full Text PDFBMC Infect Dis
December 2024
Shenzhen Third People's Hospital, National Clinical Research Centre for Infectious Disease, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, China.
Background: Bacterial pathogens frequently encounter host-derived metabolites during their colonization and invasion processes, which can serve as nutrients, antimicrobial agents, or signaling molecules for the pathogens. The essential nutrient choline (Cho) is widely known to be utilized by a diverse range of bacteria and may undergo conversion into the disease-associated metabolite trimethylamine (TMA). However, the impact of choline metabolism on bacterial physiology and virulence remains largely unexplored.
View Article and Find Full Text PDFSci Rep
December 2024
Population Health and Host Pathogen Interactions Programs, Texas Biomedical Research Institute, San Antonio, TX, USA.
In recent decades, drug resistant (DR) strains of Mycobacterium tuberculosis (M.tb), the cause of tuberculosis (TB), have emerged that threaten public health. Although M.
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