Protoplast membranes from Streptococcus pyogenes incorporated rhamnose into a preexisting polysaccharide when incubated with thymidine diphosphate rhamnose-C(14). This polysaccharide, when extracted from the membranes, did not give a precipitin reaction with group A antisera, but could be coprecipitated with added group A polysaccharide by acetone. It is presumed to be a precursor to group specific polysaccharide of the streptococcal cell wall.
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http://dx.doi.org/10.1126/science.140.3565.400 | DOI Listing |
BMC Oral Health
January 2025
Department of Stomatology, School of Medicine, Xiamen University, Xiamen, China.
Background: To investigate the antibiofilm effect and mechanism of the silver nanowire (AgNW)-modified glass ionomer cement (GIC) against multi-species oral biofilm, and to examine the mechanical and biochemical properties of this novel GIC material.
Methods: Conventional GIC was incorporated with different concentrations of AgNW and silver nanoparticles (AgNP). Multi-species biofilms of Streptococcus mutans, Streptococcus sobrinus, Lactobacillus fermentum, and Lactobacillus rhamnosus were cultured for 72 h on GIC specimens.
Am J Respir Cell Mol Biol
January 2025
The University of Texas Medical Branch at Galveston, Microbiology and Immuology, Galveston, Texas, United States.
Exposure to influenza A virus (IAV), respiratory syncytial virus (RSV), and human metapneumovirus (hMPV) is well-known to increase the risk of pneumonia in humans. Type I interferon (IFN-I) is a hallmark response to acute viral infections, and alveolar macrophages (AMs) constitute the first line of airway defense against opportunistic bacteria. Our study reveals that virus-induced IFN-I receptor (IFNAR1) signaling directly impairs AM-dependent antibacterial protection.
View Article and Find Full Text PDFmSphere
January 2025
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Unlabelled: During infection, bacterial pathogens rely on secreted virulence factors to manipulate the host cell. However, in gram-positive bacteria, the molecular mechanisms underlying the folding and activity of these virulence factors after membrane translocation are not clear. Here, we solved the protein structures of two secreted parvulin and two secreted cyclophilin-like peptidyl-prolyl isomerase (PPIase) ATP-independent chaperones found in gram-positive streptococcal species.
View Article and Find Full Text PDFInfect Immun
January 2025
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA.
Streptococcal pyogenic exotoxins (Spe proteins) secreted by (group A , GAS) are responsible for scarlet fever and streptococcal toxic shock syndrome. Most Spes are superantigens that cause excessive inflammation by activating large numbers of T cells. However, Streptococcal pyogenic exotoxin B (SpeB) is an exception, which is pro-inflammatory through its protease activity.
View Article and Find Full Text PDFClin Oral Implants Res
January 2025
Etiology and Therapy of Periodontal and Periimplant Diseases (ETEP) Research Group, Faculty of Dentistry, Complutense University, Madrid, Spain.
Aim: To evaluate in vitro the antibacterial efficacy and cytocompatibility of different implant-decontamination methods, using both 2D and 3D peri-implant mucosa models.
Methods: Four decontamination methods [chlorhexidine (CHX), electrolytic treatment (GS), curcumin (CUR), xanthohumol (XN)] were compared in four independent experiments, three with a 2D peri-implant mucosa model on titanium surfaces and another on a 3D peri-implant mucosa model. These decontamination procedures were tested for their antibacterial effect using a multispecies biofilm model with Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis for 24 h.
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