The pore forming toxin of Serratia marcescens (ShlA) is secreted and activated by an outer membrane protein (ShlB). Activation of inactive ShlA (termed ShlA*) by ShlB is dependent on phosphatidylethanolamine (PE). Activation may be a covalent modification of ShlA. To test this hypothesis, the responsible activation domain (in the N-terminal 255 amino acids of ShlA) was isolated from whole bacteria with 8 M urea in an inactive form (ShlA-255*) and from the culture supernatant in an active form (ShlA-255), followed by a two-step purification by anion-exchange chromatography and gel permeation chromatography. Comparison of a tryptic peptide map of both forms with subsequent electrospray mass spectrometry (ES-MS) and sequencing by tandem ES-MS revealed no modification. These data imply that ShlB presumably imposes a conformation on ShlA-255 that triggers activity.
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http://dx.doi.org/10.1016/s0378-4347(99)00381-3 | DOI Listing |
Nat Microbiol
January 2025
Section of General Surgery, Department of Surgery, University of Chicago, Chicago, IL, USA.
Sepsis is a major cause of morbidity and mortality, but our understanding of the mechanisms underlying survival or susceptibility is limited. Here, as pathogens often subvert host defence mechanisms, we hypothesized that this might influence the outcome of sepsis. We used microbiota analysis, faecal microbiota transplantation, antibiotic treatment and caecal metabolite analysis to show that gut-microbiota-derived tryptophan metabolites including indoles increased host survival in a mouse model of Serratia marcescens sepsis.
View Article and Find Full Text PDFPlants (Basel)
December 2024
Department of Biology, College of Science, Qassim University, Qassim 51452, Saudi Arabia.
The arid mountainous region of Hail in Saudi Arabia has a variety of desert vegetation, some of which are conventionally used in Bedouin traditional medicine. These plants need scientific examination. This research seeks to examine using a thorough multi-analytical methodology that includes antibacterial and antioxidant assessments as well as computational modeling.
View Article and Find Full Text PDFToxics
December 2024
Postgraduate Program in Biotechnology and Biosciences, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina-Campus Reitor João David Ferreira Lima, Florianópolis 88040-900, SC, Brazil.
Bioremediation, involving the strategic use of microorganisms, has proven to be a cost-effective alternative for restoring areas impacted by persistent contaminants such as polycyclic aromatic hydrocarbons (PAHs). In this context, the aim of this study was to explore hydrocarbon-degrading microbial consortia by prospecting native species from soils contaminated with blends of diesel and biodiesel (20% biodiesel/80% diesel). After enrichment in a minimal medium containing diesel oil as the sole carbon source and based on 16S rRNA, Calmodulin and β-tubulin gene sequencing, seven fungi and 12 bacteria were identified.
View Article and Find Full Text PDFInsects
December 2024
College of Plant Protection, South China Agricultural University, Guangzhou 510642, China.
Ants as social insects live in groups, which increases the risk of contagious diseases. In response to the threat of pathogens, ants have evolved a variety of defense mechanisms, including incorporating antimicrobial chemicals into nest material for nest hygiene. is an arboreal ant, building its nest using plant tissues.
View Article and Find Full Text PDFEmerg Microbes Infect
January 2025
Department of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Shenzhen Third People's Hospital, Shenzhen, Guangdong Province 518112, China.
() commonly induces refractory infection due to its multidrug-resistant nature. To date, there have been no reports on the application of phage treatment for infection. This study was conducted to explore the feasibility of phage application in treating refractory infection by collaborating with a 59-year-old male patient with a pulmonary infection of multidrug-resistant Our experiments included three domains: ) selection of the appropriate phage, ) verification of the efficacy and safety of the selected phage, ) confirmation of phage-bacteria interactions.
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