The Experts below are selected from a list of 1893 Experts worldwide ranked by ideXlab platform

Simon Ittig - One of the best experts on this subject based on the ideXlab platform.

  • modification of the 1 phosphate group during biosynthesis of capnocytophaga canimorsus lipid a
    2016
    Co-Authors: Francesco Renzi, Ulrich Zahringer, Courtney E Chandler, Robert K Ernst, Guy R Cornelis, Simon Ittig
    Abstract:

    Capnocytophaga canimorsus, a commensal bacterium of dog's Mouth Flora causing severe infections in humans after dog bites or scratches, has a lipopolysaccharide (LPS) (endotoxin) with low-inflammatory lipid A. In particular, it contains a phosphoethanolamine (P-Etn) instead of a free phosphate group at the C-1 position of the lipid A backbone, usually present in highly toxic enterobacterial Gram-negative lipid A. Here we show that the C. canimorsus genome comprises a single operon encoding a lipid A 1-phosphatase (LpxE) and a lipid A 1 P-Etn transferase (EptA). This suggests that lipid A is modified during biosynthesis after completing acylation of the backbone by removal of the 1-phosphate and subsequent addition of an P-Etn group. As endotoxicity of lipid A is known to depend largely on the degree of unsubstituted or unmodified phosphate residues, deletion of lpxE or eptA led to mutants lacking the P-Etn group, with consequently increased endotoxicity and decreased resistance to cationic antimicrobial peptides (CAMP). Consistent with the proposed sequential biosynthetic mechanism, the endotoxicity and CAMP resistance of a double deletion mutant of lpxE-eptA was similar to that of a single lpxE mutant. Finally, the proposed enzymatic activities of LpxE and EptA based on sequence similarity could be successfully validated by mass spectrometry (MS)-based analysis of lipid A isolated from the corresponding deletion mutant strains.

Thomas P. Sculco - One of the best experts on this subject based on the ideXlab platform.

  • pasteurella multocida infection in total knee arthroplasty case report and literature review
    1992
    Co-Authors: Tammy L Guion, Thomas P. Sculco
    Abstract:

    Pasteurella multocida, a small gram-negative bacterium, is part of the normal Mouth Flora of many animals, including domestic cats and dogs. While commonly associated with infections in animals, it is a rare cause of human disease. The majority of Pasteurella infections in humans occur with percutaneous inoculation of the organism following a bite by a cat or dog, although disease without antecedent animal exposure or with causal animal contact does occur. The spectrum of disease produced ranges from localized, including abscess, cellulitis, lymphadenopathy, and osteomyelitis, to systemic, with septicemia, septic arthritis, respiratory, and central nervous system involvement. Altered host defenses and underlying chronic disease, such as rheumatoid arthritis, corticosteroid therapy, and severe hepatic or renal disease, may predispose to more serious systemic manifestations of infection. The authors report a case of P. multocida infection in a total knee arthroplasty as a result of a dog scratch and review the literature reporting P. multocida infections in total knee arthroplasty.

Francesco Renzi - One of the best experts on this subject based on the ideXlab platform.

  • modification of the 1 phosphate group during biosynthesis of capnocytophaga canimorsus lipid a
    2016
    Co-Authors: Francesco Renzi, Ulrich Zahringer, Courtney E Chandler, Robert K Ernst, Guy R Cornelis, Simon Ittig
    Abstract:

    Capnocytophaga canimorsus, a commensal bacterium of dog's Mouth Flora causing severe infections in humans after dog bites or scratches, has a lipopolysaccharide (LPS) (endotoxin) with low-inflammatory lipid A. In particular, it contains a phosphoethanolamine (P-Etn) instead of a free phosphate group at the C-1 position of the lipid A backbone, usually present in highly toxic enterobacterial Gram-negative lipid A. Here we show that the C. canimorsus genome comprises a single operon encoding a lipid A 1-phosphatase (LpxE) and a lipid A 1 P-Etn transferase (EptA). This suggests that lipid A is modified during biosynthesis after completing acylation of the backbone by removal of the 1-phosphate and subsequent addition of an P-Etn group. As endotoxicity of lipid A is known to depend largely on the degree of unsubstituted or unmodified phosphate residues, deletion of lpxE or eptA led to mutants lacking the P-Etn group, with consequently increased endotoxicity and decreased resistance to cationic antimicrobial peptides (CAMP). Consistent with the proposed sequential biosynthetic mechanism, the endotoxicity and CAMP resistance of a double deletion mutant of lpxE-eptA was similar to that of a single lpxE mutant. Finally, the proposed enzymatic activities of LpxE and EptA based on sequence similarity could be successfully validated by mass spectrometry (MS)-based analysis of lipid A isolated from the corresponding deletion mutant strains.

Tammy L Guion - One of the best experts on this subject based on the ideXlab platform.

  • pasteurella multocida infection in total knee arthroplasty case report and literature review
    1992
    Co-Authors: Tammy L Guion, Thomas P. Sculco
    Abstract:

    Pasteurella multocida, a small gram-negative bacterium, is part of the normal Mouth Flora of many animals, including domestic cats and dogs. While commonly associated with infections in animals, it is a rare cause of human disease. The majority of Pasteurella infections in humans occur with percutaneous inoculation of the organism following a bite by a cat or dog, although disease without antecedent animal exposure or with causal animal contact does occur. The spectrum of disease produced ranges from localized, including abscess, cellulitis, lymphadenopathy, and osteomyelitis, to systemic, with septicemia, septic arthritis, respiratory, and central nervous system involvement. Altered host defenses and underlying chronic disease, such as rheumatoid arthritis, corticosteroid therapy, and severe hepatic or renal disease, may predispose to more serious systemic manifestations of infection. The authors report a case of P. multocida infection in a total knee arthroplasty as a result of a dog scratch and review the literature reporting P. multocida infections in total knee arthroplasty.

Alan B Lumsden - One of the best experts on this subject based on the ideXlab platform.