Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The composition of the peptidoglycan of Haemophilus influenzae was determined by analyzing glycopeptides generated by M1 muramidase hydrolysis using high pressure liquid chromatography, fast atom bombardment mass spectrometry, and fast atom bombardment collisionally activated dissociation tandem mass spectrometry, and amino acid analysis. The structures of 17 glycopeptides, representing 96% of the total peptidoglycan, were ascertained. Fifteen glycopeptides resembled species described for Escherichia coli peptidoglycan (Glauner, B., and Schwarz, U. (1983) The Target of Penicillin (Hackenbeck, R., ed), Walter de Gruyter, Berlin pp. 29-34) as compared with 9 in common with Bordetella pertussis (Tuomanen, E., Schwartz, J., Sande, S., Light, K., and Gage, D. (1989) J. Biol. Chem. 264, 11093-11098). Substitutions for L-alanine in the fourth position of the stem peptide included glycine, aspartic acid, and serine. The peptidoglycan was 27% cross-linked, 2% of which formed between diaminopimelic acid residues. No species was identified containing lysyl-arginine residues characteristic of lipoprotein. The peptidoglycan of non-beta-lactamase-mediated antibiotic-resistant H. influenzae differed from that of sensitive strains by an increase in the amount of disaccharide tripeptides and a decrease in 1,6-anhydro dimers. Both changes were transformable properties that changed in a stepwise fashion in parallel with the degree of antibiotic resistance.
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PMID:Composition of the peptidoglycan of Haemophilus influenzae. 850 90

Cell-free lung lavage fluid (LLF) from healthy normal rats killed phase I (wild-type, virulent) Bordetella pertussis at 37 degrees C in vitro. B. parapertussis was also killed by the LLF, but phase IV (avirulent mutant) B. pertussis and some other common bacterial species, including B. bronchiseptica, were not. Transmission electron microscopy of thin sections of the phase I B. pertussis showed extensive structural damage and cell lysis. None of the other mammalian species tested had LLF with bactericidal activity against B. pertussis as high as that of the rat. Rats killed with halothane yielded LLF with higher bactericidal activity than when CO2 was used. Ultracentrifugation of LLF at 55,000 g gave a surfactant (pellet) fraction that had c. 95% of the bactericidal activity and which was biochemically distinct from the 5% of activity in the supernate fraction. Phospholipids and fatty acids appeared to be involved in LLF bactericidal activity, but not complement or lysozyme. Arachidonic acid was the most active of the fatty acids tested. Artificial surfactant, as used in premature infants, had no bactericidal effect on B. pertussis.
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PMID:Bactericidal activity of rat lung lavage fluid against Bordetella pertussis. 1040 14

The family of peptidoglycan recognition proteins (PGRPs) is conserved from insects to mammals. Recently, Drosophila PGRP-SC1B was demonstrated to be an N-acetylmuramoyl-L-alanine amidase (NAMLAA), an enzyme that cleaves the lactylamide bond between muramic acid and the peptide chain in peptidoglycan (PGN). We now show an M x mPGRP-L mRNA to be expressed in the liver. The recombinant M x mPGRP-L protein has NAMLAA activity and degrades PGN from both Escherichia coli and Staphylococcus aureus; however, the Gram-positive PGN was a better substrate after lysozyme treatment. The activity of M x mPGRP-L was further analysed using Bordetella pertussis tracheal toxin as a substrate. Cleavage products were separated on HPLC and identified using mass spectrometry. From these results we conclude that M x mPGRP-L has activity and other properties identifying it as the NAMLAA protein present in mammalian sera.
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PMID:A mammalian peptidoglycan recognition protein with N-acetylmuramoyl-L-alanine amidase activity. 1282 Nov 40

The airway provides numerous defense mechanisms to prevent microbial colonization by the large numbers of bacteria and viruses present in ambient air. An important component of this defense is the antimicrobial peptides and proteins present in the airway surface fluid (ASF), the mucin-rich fluid covering the respiratory epithelium. These include larger proteins such as lysozyme and lactoferrin, as well as the cationic defensin and cathelicidin peptides. While some of these peptides, such as human beta-defensin (hBD)-1, are present constitutively, others, including hBD2 and -3 are inducible in response to bacterial recognition by Toll-like receptor-mediated pathways. These peptides can act as microbicides in the ASF, but also exhibit other activities, including potent chemotactic activity for cells of the innate and adaptive immune systems, suggesting they play a complex role in the host defense of the airway. Inhibition of antimicrobial peptide activity or gene expression can result in increased susceptibility to infections. This has been observed with cystic fibrosis (CF), where the CF phenotype leads to reduced antimicrobial capacity of peptides in the airway. Pathogenic virulence factors can inhibit defensin gene expression, as can environmental factors such as air pollution. Such an interference can result in infections by airway-specific pathogens including Bordetella bronchiseptica, Mycobacterium tuberculosis, and influenza virus. Research into the modulation of peptide gene expression in animal models, as well as the optimization of peptide-based therapeutics shows promise for the treatment and prevention of airway infectious diseases.
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PMID:Antimicrobial peptides in the airway. 1690 21

The dlt operon encodes proteins that alanylate teichoic acids, the major components of cell walls of gram-positive bacteria. This generates a net positive charge on bacterial cell walls, repulsing positively charged molecules and conferring resistance to animal and human cationic antimicrobial peptides (AMPs) in gram-positive pathogenic bacteria. AMPs damage the bacterial membrane and are the most effective components of the humoral immune response against bacteria. We investigated the role of the dlt operon in insect virulence by inactivating this operon in Bacillus cereus, which is both an opportunistic human pathogen and an insect pathogen. The Delta dlt(Bc) mutant displayed several morphological alterations but grew at a rate similar to that for the wild-type strain. This mutant was less resistant to protamine and several bacterial cationic AMPs, such as nisin, polymyxin B, and colistin, in vitro. It was also less resistant to molecules from the insect humoral immune system, lysozyme, and cationic AMP cecropin B from Spodoptera frugiperda. Delta dlt(Bc) was as pathogenic as the wild-type strain in oral infections of Galleria mellonella but much less virulent when injected into the hemocoels of G. mellonella and Spodoptera littoralis. We detected the dlt operon in three gram-negative genera: Erwinia (Erwinia carotovora), Bordetella (Bordetella pertussis, Bordetella parapertussis, and Bordetella bronchiseptica), and Photorhabdus (the entomopathogenic bacterium Photorhabdus luminescens TT01, the dlt operon of which did not restore cationic AMP resistance in Delta dlt(Bc)). We suggest that the dlt operon protects B. cereus against insect humoral immune mediators, including hemolymph cationic AMPs, and may be critical for the establishment of lethal septicemia in insects and in nosocomial infections in humans.
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PMID:The dlt operon of Bacillus cereus is required for resistance to cationic antimicrobial peptides and for virulence in insects. 1976 27

Jules Bordet, a pioneering immunologist, lived until the dawn of molecular immunology. He was born in Belgium in 1870, obtained a medical degree in 1892, worked at l'Institut Pasteur in Paris from 1894 to 1901 and then established the Pasteur Institute of Brabant in Brussels. Before World War I, Bordet found that complement binds to antibody-antigen complexes regardless of the antigen or antibodies involved. Subsequently he developed the complement fixation test that was of diagnostic importance for several decades. For his research concerning complement he was awarded the 1919 Nobel Prize in Physiology or Medicine. During that period he also discovered anaphylatoxin, conglutinin, and the cause of whooping cough (Bordetella pertussis). After World War I he found how thrombin forms, how platelets participate in clotting, lysozyme in human milk and much of the biology of bacteriophages. In addition, Bordet worked fervently to limit weapons of mass destruction and promote peace until his death in 1961.
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PMID:Jules Bordet (1870-1961): a bridge between early and modern immunology. 2002 83

Phage display offers a powerful approach to engineer protein affinity. A naturally occurring analog to phage display, the Bordetella bronchiseptica bacteriophage (BP) employs a highly variable protein termed the major tropism determinant (Mtd) to recognize its dynamic host. Propagation of BP provides a self-made phage library (SMPL) with vast numbers of phage particles, each displaying a single Mtd variant. We report applying the diversity of the BP-SMPL to access a tyrosine-rich library of Mtd variants. Expression of the SMPL-engineered Mtd variant as a GST-bound fusion protein demonstrated specific binding to the target T4 lysozyme with dissociation constants in the sub-micromolar range. The results guide future experiments with SMPLs applied to protein engineering.
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PMID:Protein engineering with biosynthesized libraries from Bordetella bronchiseptica bacteriophage. 2340 8


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