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European Journal of Pharmaceutical... Dec 2023Staphylococcus aureus is an important pathogenic bacterium responsible for various organ infections. The serious side effects and the development of antibiotic...
Staphylococcus aureus is an important pathogenic bacterium responsible for various organ infections. The serious side effects and the development of antibiotic resistance have rendered the antibiotic therapy against S. aureus increasingly challenging, emphasizing the pressing need for the exploration of novel therapeutic agents. Our research has uncovered the promising antimicrobial properties of 8-octyl berberine (OBBR), a novel compound derived from berberine (BBR), against S. aureus. OBBR exhibited a minimum inhibitory concentration (MIC) of 1.0 μg/mL, which closely approximated that of levofloxacin. Intriguingly, a multipassage resistance assay demonstrated that the MIC of OBBR against S. aureus remained relatively stable, while levofloxacin exhibited a 4-fold increase over 20 days, suggesting that OBBR was less prone to inducing resistance. Mechanistically, our investigation, employing Zeta potential measurements, flow cytometry, scanning electron microscopy, and transmission electron microscopy, unveiled that OBBR induced morphological alterations in the bacteria. Furthermore, it disrupted the bacterial cell wall and membrane by altering membrane potential and compromising membrane integrity. These actions culminated in bacterial disintegration and apoptosis. Transcriptomic analysis shed light on significant downregulation of gene ontology terms, predominantly associated with membranes. The Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis implicated OBBR in disturbing peptidoglycan biosynthesis, with the membrane protein MraY emerging as a potential target for OBBR's action against S. aureus. Notably, experiments involving the overexpression of MraY confirmed OBBR's inhibitory effect on peptidoglycan synthesis. Furthermore, molecular docking and cellular thermal shift assay revealed OBBR's direct interaction with MraY, potentially leading to the inhibition of the enzymatic activity of MraY and, consequently, impeding peptidoglycan synthesis. In summary, OBBR, by targeting MraY and inhibiting peptidoglycan synthesis, emerges as a promising alternative antibiotic against S. aureus, offering potential advantages in terms of limited drug resistance development.
Topics: Humans; Staphylococcus aureus; Berberine; Peptidoglycan; Molecular Docking Simulation; Levofloxacin; Anti-Bacterial Agents; Staphylococcal Infections; Microbial Sensitivity Tests
PubMed: 37806408
DOI: 10.1016/j.ejps.2023.106602 -
Methods in Molecular Biology (Clifton,... 2017In the last decade, more and more plant receptors for complex carbohydrate structures have been described. However, studies on receptor binding to glycan ligands are...
In the last decade, more and more plant receptors for complex carbohydrate structures have been described. However, studies on receptor binding to glycan ligands are often hampered due to the technical challenge to obtain pure preparations of homogeneous carbohydrate ligands such as bacterial peptidoglycan (PGN) in amounts suitable for studying protein-glycan interactions. Also, most approaches rely on the availability of defined soluble ligands, which in the case of glycans can rarely be synthesized but have to be purified from the respective microorganism. In this chapter, we describe the purification of complex PGN from sources such as gram-positive bacteria, from which PGN isolation is facilitated due to its larger content in their cell wall. Insoluble PGN can subsequently be used in simple carbohydrate pull-down assays to test for interaction with plant proteins. In this respect, lysin motif (LysM)-domain containing proteins are of particular interest. All plant receptors described to date to be involved in the perception of N-Acetylglucosamine-containing ligands (such as PGN or chitin) have been shown to belong to this protein class. Thus, this chapter will also include the production of recombinant LysM proteins to analyze their PGN interaction.
Topics: Amino Acid Motifs; Binding Sites; Gram-Positive Bacteria; Lysine; Peptidoglycan; Polysaccharides, Bacterial; Receptors, Pattern Recognition; Saccharomyces cerevisiae
PubMed: 28220411
DOI: 10.1007/978-1-4939-6859-6_1 -
Journal of Endotoxin Research 2005Peptidoglycan (murein) is a major essential and specific constituent of the bacterial cell wall. Its main function is to protect cells against the internal osmotic... (Review)
Review
Peptidoglycan (murein) is a major essential and specific constituent of the bacterial cell wall. Its main function is to protect cells against the internal osmotic pressure and to maintain the characteristic cell shape. It also serves as a platform for the anchoring of specific proteins and other cell wall components. This giant macromolecule is composed of long glycan chains cross-linked by short peptides. Any alteration of the disaccharide-peptide basic unit results in a global change of peptidoglycan structure and properties. Such global variations are encountered in nature as conserved variations along phyletic lines but have sometimes been acquired as a result of mutations or as a mechanism of resistance against cell-wall targeted antibiotics. During bacterial cell growth and division, the peptidoglycan mesh is constantly broken down by a set of highly specific hydrolases in a maturation process allowing insertion of newly synthesized units in the pre-existing polymerized material. Depending on the bacterial species considered, degradation fragments are either released in the growth medium or efficiently re-utilized for synthesis of new murein in a sequence of events termed the recycling pathway. Peptidoglycan is one of the main pathogen-associated molecular patterns recognized by the host innate immune system. Variations of the structure and metabolism of this cell wall component have been exploited by host defense mechanisms for detection/identification of invading bacterial species. Modification of the peptidoglycan structure could also represent a mechanism allowing bacteria to escape these host defense systems.
Topics: Animals; Carbohydrate Sequence; Drosophila; Immunity, Innate; Molecular Sequence Data; Peptidoglycan
PubMed: 15949137
DOI: 10.1179/096805105X35233 -
Methods in Enzymology 1994
Review
Topics: Acetylglucosamine; Amino Acid Sequence; Artifacts; Carbohydrate Sequence; Chromatography, High Pressure Liquid; Gram-Negative Bacteria; Gram-Positive Bacteria; Molecular Sequence Data; Muramic Acids; Peptide Fragments; Peptidoglycan; Solubility
PubMed: 8057899
DOI: 10.1016/0076-6879(94)35146-5 -
Chembiochem : a European Journal of... Mar 2009Because of its importance for bacterial cell survival, the bacterial cell wall is an attractive target for new antibiotics in a time of great demand for new antibiotic... (Review)
Review
Because of its importance for bacterial cell survival, the bacterial cell wall is an attractive target for new antibiotics in a time of great demand for new antibiotic compounds. Therefore, more knowledge about the diverse processes related to bacterial cell wall synthesis is needed. The cell wall is located on the exterior of the cell and consists mainly of peptidoglycan, a large macromolecule built up from a three-dimensional network of aminosugar strands interlinked with peptide bridges. The subunits of peptidoglycan are synthesized inside the cell before they are transported to the exterior in order to be incorporated into the growing peptidoglycan. The high flexibility of the cell wall synthesis machinery towards unnatural derivatives of these subunits enables research on the bacterial cell wall using labeled compounds. This review highlights the high potential of labeled cell wall precursors in various areas of cell wall research. Labeled precursors can be used in investigating direct cell wall-antibiotic interactions and in cell wall synthesis and localization studies. Moreover, these compounds can provide a powerful tool in the elucidation of the cell wall proteome, the "wallosome," and thus, might provide new targets for antibiotics.
Topics: Bacteria; Cell Wall; Peptidoglycan; Protein Precursors; Staining and Labeling; Substrate Specificity
PubMed: 19173317
DOI: 10.1002/cbic.200800678 -
Journal of Industrial Microbiology &... Apr 2021This study evaluates peptidoglycan hydrolysis by a microbial muramidase from the fungus Acremonium alcalophilum in vitro and in the gastrointestinal tract of broiler...
This study evaluates peptidoglycan hydrolysis by a microbial muramidase from the fungus Acremonium alcalophilum in vitro and in the gastrointestinal tract of broiler chickens. Peptidoglycan used for in vitro studies was derived from 5 gram-positive chicken gut isolate type strains. In vitro peptidoglycan hydrolysis was studied by three approaches: (a) helium ion microscopy to identify visual phenotypes of hydrolysis, (b) reducing end assay to quantify solubilization of peptidoglycan fragments, and (c) mass spectroscopy to estimate relative abundances of soluble substrates and reaction products. Visual effects of peptidoglycan hydrolysis could be observed by helium ion microscopy and the increase in abundance of soluble peptidoglycan due to hydrolysis was quantified by a reducing end assay. Mass spectroscopy confirmed the release of hydrolysis products and identified muropeptides from the five different peptidoglycan sources. Peptidoglycan hydrolysis in chicken crop, jejunum, and caecum samples was measured by quantifying the total and soluble muramic acid content. A significant increase in the proportion of the soluble muramic acid was observed in all three segments upon inclusion of the microbial muramidase in the diet.
Topics: Acremonium; Animals; Chickens; Gastrointestinal Tract; Hydrolysis; Male; Muramidase; Peptidoglycan
PubMed: 33693885
DOI: 10.1093/jimb/kuab008 -
Nature Communications May 2015Planctomycetes are intriguing microorganisms that apparently lack peptidoglycan, a structure that controls the shape and integrity of almost all bacterial cells....
Planctomycetes are intriguing microorganisms that apparently lack peptidoglycan, a structure that controls the shape and integrity of almost all bacterial cells. Therefore, the planctomycetal cell envelope is considered exceptional and their cell plan uniquely compartmentalized. Anaerobic ammonium-oxidizing (anammox) Planctomycetes play a key role in the global nitrogen cycle by releasing fixed nitrogen back to the atmosphere as N2. Here using a complementary array of state-of-the-art techniques including continuous culturing, cryo-transmission electron microscopy, peptidoglycan-specific probes and muropeptide analysis, we show that the anammox bacterium Kuenenia stuttgartiensis contains peptidoglycan. On the basis of the thickness, composition and location of peptidoglycan in K. stuttgartiensis, we propose to redefine Planctomycetes as Gram-negative bacteria. Our results demonstrate that Planctomycetes are not an exception to the universal presence of peptidoglycan in bacteria.
Topics: Ammonium Compounds; Anaerobiosis; Cell Wall; Oxidation-Reduction; Peptidoglycan; Planctomycetales
PubMed: 25962786
DOI: 10.1038/ncomms7878 -
Research in Microbiology 1998The organization of chains of oligopeptidoglycan in the saccular wall is of critical importance in the study of the mechanism and physiology of prokaryotic wall growth.... (Review)
Review
The organization of chains of oligopeptidoglycan in the saccular wall is of critical importance in the study of the mechanism and physiology of prokaryotic wall growth. The electron microphotographs of De Pedro et al. present new findings and can be used to negate or at least raise questions about the previously accepted conclusion that the glycan chains are oriented transversely to the axis of rod-shaped Escherichia coli. This suggests caution in assuming that the glycan chains in the murein structure are parallel to each other and are perpendicular to the axis of the cell. These results should reopen the question of not only the orientation of the peptidoglycan chains, but the possibility of variability in orientation. Three classes of hypotheses about wall growth are reconsidered and problems with them are presented. The new results from De Pedro's laboratory and the experimental glycan chain length distribution argue against proposed systematic models. These include models that postulate belts or hoops stretched around the circumference of the cell and mechanisms that insert new chains of the length of presumptive "docking" strands in the stress-bearing wall. They are consistent, however, with the surface stress theory that proposes that random enzyme action together with physical forces are involved in the elongation of the rod-shaped Gram-negative wall.
Topics: Cell Wall; Escherichia coli; Models, Molecular; Peptidoglycan
PubMed: 9921576
DOI: 10.1016/s0923-2508(99)80016-3 -
PloS One 2014Plants are constantly under attack from a variety of microorganisms, and rely on a series of complex detection and response systems to protect themselves from infection....
Plants are constantly under attack from a variety of microorganisms, and rely on a series of complex detection and response systems to protect themselves from infection. Here, we found that a by-product of glutamate fermentation triggered defense responses in grapevine, increasing the expression of defense response genes in cultured cells, foliar chitinase activity, and resistance to infection by downy mildew in leaf explants. To identify the molecule that triggered this innate immunity, we fractionated and purified candidates extracted from Corynebacterium glutamicum, a bacterium used in the production of amino acids by fermentation. Using hydrolysis by lysozyme, a silkworm larva plasma detection system, and gel filtration analysis, we identified peptidoglycan as inducing the defense responses. Peptidoglycans of Escherichia coli, Bacillus subtilis, and Staphylococcus aureus also generated similar defensive responses.
Topics: Bacillus subtilis; Chitinases; Complex Mixtures; Corynebacterium glutamicum; Escherichia coli; Fermentation; Gene Expression Regulation, Plant; Glutamic Acid; Peptidoglycan; Peronospora; Plant Diseases; Plant Immunity; Plant Leaves; Plant Proteins; Staphylococcus aureus; Vitis
PubMed: 25427192
DOI: 10.1371/journal.pone.0113340 -
Nihon Saikingaku Zasshi. Japanese... May 2005
Review
Topics: Amidohydrolases; Animals; Carrier Proteins; Drosophila melanogaster; Humans; Immunity, Innate; Multigene Family; Peptidoglycan; Signal Transduction
PubMed: 15966365
DOI: 10.3412/jsb.60.389