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Artykuły w czasopismach na temat "Peptidoglycan metabolism"
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Garcia, Daniel L., i Joseph P. Dillard. "Mutations in ampG or ampD Affect Peptidoglycan Fragment Release from Neisseria gonorrhoeae". Journal of Bacteriology 190, nr 11 (4.04.2008): 3799–807. http://dx.doi.org/10.1128/jb.01194-07.
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ABSTRACT Neisseria gonorrhoeae releases peptidoglycan fragments during growth. The majority of the fragments released are peptidoglycan monomers, molecules known to increase pathogenesis through the induction of proinflammatory cytokines and responsible for the killing of ciliated epithelial cells. In other gram-negative bacteria such as Escherichia coli, these peptidoglycan fragments are efficiently degraded and recycled. Peptidoglycan fragments enter the cytoplasm from the periplasm via the AmpG permease. The amidase AmpD degrades peptidoglycan monomers by removing the disaccharide from the peptide. The disaccharide and the peptide are further degraded and are then used for new peptidoglycan synthesis or general metabolism. We examined the possibility that peptidoglycan fragment release by N. gonorrhoeae results from defects in peptidoglycan recycling. The deletion of ampG caused a large increase in peptidoglycan monomer release. Analysis of cytoplasmic material showed peptidoglycan fragments as recycling intermediates in the wild-type strain but absent from the ampG mutant. An ampD deletion reduced the release of all peptidoglycan fragments and nearly eliminated the release of free disaccharide. The ampD mutant also showed a large buildup of peptidoglycan monomers in the cytoplasm. The introduction of an ampG mutation in the ampD background restored peptidoglycan fragment release, indicating that events in the cytoplasm (metabolic or transcriptional regulation) affect peptidoglycan fragment release. The ampD mutant showed increased metabolism of exogenously added free disaccharide derived from peptidoglycan. These results demonstrate that N. gonorrhoeae has an active peptidoglycan recycling pathway and can regulate peptidoglycan fragment metabolism, dependent on the intracellular concentration of peptidoglycan fragments.
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Strating, Hendrik, Chris Vandenende i Anthony J. Clarke. "Changes in peptidoglycan structure and metabolism during differentiation ofProteus mirabilisinto swarmer cells". Canadian Journal of Microbiology 58, nr 10 (październik 2012): 1183–94. http://dx.doi.org/10.1139/w2012-102.
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The O-acetylation of peptidoglycan in Gram-negative bacteria occurs specifically at the C-6 hydroxyl group of muramoyl residues. The level of peptidoglycan O-acetylation was found to decrease from 51% to 29% upon differentiation of Proteus mirabilis vegetative cells to swarmers. This decrease was accompanied by a change in the muropeptide composition of the peptidoglycan. In particular, the content of anhydromuropeptides increased, while the amount of Lys-Lys-muropeptides arising from bound lipoprotein decreased. These changes together with a shift in proportion of larger muropeptides suggested a decrease in average chain length of the muropeptides from swarmer cells. Zymography using SDS–PAGE gels containing either O-acetylated or chemically de-O-acetylated peptidoglycan was used to monitor the activity of specific autolysins during the differentiation of vegetative to swarming cells of P. mirabilis. A 43 kDa autolysin with increased specificity for O-acetylated peptidoglycan was detected in vegetative cells, but its activity appeared to decrease as the cells began to differentiate, while the levels of 3 other autolysins with apparent specificity for non-O-acetylated peptidoglycan increased. These changes are discussed in relation to the autolysin profile of the bacteria and the changes in peptidoglycan composition with cell differentiation.
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Pérez Medina, Krizia, i Joseph Dillard. "Antibiotic Targets in Gonococcal Cell Wall Metabolism". Antibiotics 7, nr 3 (21.07.2018): 64. http://dx.doi.org/10.3390/antibiotics7030064.
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The peptidoglycan cell wall that encloses the bacterial cell and provides structural support and protection is remodeled by multiple enzymes that synthesize and cleave the polymer during growth. This essential and dynamic structure has been targeted by multiple antibiotics to treat gonococcal infections. Up until now, antibiotics have been used against the biosynthetic machinery and the therapeutic potential of inhibiting enzymatic activities involved in peptidoglycan breakdown has not been explored. Given the major antibiotic resistance problems we currently face, it is crucial to identify other possible targets that are key to maintaining cell integrity and contribute to disease development. This article reviews peptidoglycan as an antibiotic target, how N. gonorrhoeae has developed resistance to currently available antibiotics, and the potential of continuing to target this essential structure to combat gonococcal infections by attacking alternative enzymatic activities involved in cell wall modification and metabolism.
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Vasudevan, Pradeep, Jessica McElligott, Christa Attkisson, Michael Betteken i David L. Popham. "Homologues of the Bacillus subtilis SpoVB Protein Are Involved in Cell Wall Metabolism". Journal of Bacteriology 191, nr 19 (31.07.2009): 6012–19. http://dx.doi.org/10.1128/jb.00604-09.
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ABSTRACT Members of the COG2244 protein family are integral membrane proteins involved in synthesis of a variety of extracellular polymers. In several cases, these proteins have been suggested to move lipid-linked oligomers across the membrane or, in the case of Escherichia coli MviN, to flip the lipid II peptidoglycan precursor. Bacillus subtilis SpoVB was the first member of this family implicated in peptidoglycan synthesis and is required for spore cortex polymerization. Three other COG2244 members with high similarity to SpoVB are encoded within the B. subtilis genome. Mutant strains lacking any or all of these genes (yabM, ykvU, and ytgP) in addition to spoVB are viable and produce apparently normal peptidoglycan, indicating that their function is not essential in B. subtilis. Phenotypic changes associated with loss of two of these genes suggest that they function in peptidoglycan synthesis. Mutants lacking YtgP produce long cells and chains of cells, suggesting a role in cell division. Mutants lacking YabM exhibit sensitivity to moenomycin, an antibiotic that blocks peptidoglycan polymerization by class A penicillin-binding proteins. This result suggests that YabM may function in a previously observed alternate pathway for peptidoglycan strand synthesis.
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Dörries, Kirsten, Rabea Schlueter i Michael Lalk. "Impact of Antibiotics with Various Target Sites on the Metabolome of Staphylococcus aureus". Antimicrobial Agents and Chemotherapy 58, nr 12 (15.09.2014): 7151–63. http://dx.doi.org/10.1128/aac.03104-14.
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ABSTRACTIn this study, global intra- and extracellular metabolic profiles were exploited to investigate the impact of antibiotic compounds with different cellular targets on the metabolome ofStaphylococcus aureusHG001. Primary metabolism was largely covered, yet uncommon staphylococcal metabolites were detected in the cytosol ofS. aureus, including sedoheptulose-1,7-bisphosphate and the UDP-MurNAc-pentapeptide with an alanine-seryl residue. By comparing the metabolic profiles of unstressed and stressed staphylococcal cells in a time-dependent manner, we found far-ranging effects within the metabolome. For each antibiotic compound, accumulation as well as depletion of metabolites was detected, often comprising whole biosynthetic pathways, such as central carbon and amino acid metabolism and peptidoglycan, purine, and pyrimidine synthesis. Ciprofloxacin altered the pool of (deoxy)nucleotides as well as peptidoglycan precursors, thus linking stalled DNA and cell wall synthesis. Erythromycin tended to increase the amounts of intermediates of the pentose phosphate pathway and lysine. Fosfomycin inhibited the first enzymatic step of peptidoglycan synthesis, which was followed by decreased levels of peptidoglycan precursors but enhanced levels of substrates such as UDP-GlcNAc and alanine-alanine. In contrast, vancomycin and ampicillin inhibited the last stage of peptidoglycan construction on the outer cell surface. As a result, the amounts of UDP-MurNAc-peptides drastically increased, resulting in morphological alterations in the septal region and in an overall decrease in central metabolite levels. Moreover, each antibiotic affected intracellular levels of tricarboxylic acid cycle intermediates.
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Fernández, Ana, Astrid Pérez, Juan A. Ayala, Susana Mallo, Soraya Rumbo-Feal, Maria Tomás, Margarita Poza i Germán Bou. "Expression of OXA-Type and SFO-1 β-Lactamases Induces Changes in Peptidoglycan Composition and Affects Bacterial Fitness". Antimicrobial Agents and Chemotherapy 56, nr 4 (30.01.2012): 1877–84. http://dx.doi.org/10.1128/aac.05402-11.
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ABSTRACTβ-Lactamases and penicillin-binding proteins (PBPs) have evolved from a common ancestor. β-Lactamases are enzymes that degrade β-lactam antibiotics, whereas PBPs are involved in the synthesis and processing of peptidoglycan, which forms an elastic network in the bacterial cell wall. This study analyzed the interaction between β-lactamases and peptidoglycan and the impact on fitness and biofilm production. A representative set of all classes of β-lactamases was cloned in the expression vector pBGS18 under the control of the CTX-M promoter and expressed inEscherichia coliMG1655. The peptidoglycan composition of all clones was evaluated, and quantitative changes were found inE. colistrains expressing OXA-24, OXA-10-like, and SFO-1 (with its upstream regulator AmpR) β-lactamases; the level of cross-linked muropeptides decreased, and their average length increased. These changes were associated with a statistically significant fitness cost, which was demonstrated in bothin vitroandin vivoexperiments. The observed changes in peptidoglycan may be explained by the presence of residualdd-endopeptidase activity in these β-lactamases, which may result in hydrolysis of the peptide cross bridge. The biological cost associated with these changes provides important data regarding the interaction between β-lactamases and the metabolism of peptidoglycan and may provide an explanation for the epidemiology of these β-lactamases inEnterobacteriaceae.
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Maitra, Arundhati, Tulika Munshi, Jess Healy, Liam T. Martin, Waldemar Vollmer, Nicholas H. Keep i Sanjib Bhakta. "Cell wall peptidoglycan in Mycobacterium tuberculosis: An Achilles’ heel for the TB-causing pathogen". FEMS Microbiology Reviews 43, nr 5 (10.06.2019): 548–75. http://dx.doi.org/10.1093/femsre/fuz016.
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ABSTRACTTuberculosis (TB), caused by the intracellular pathogen Mycobacterium tuberculosis, remains one of the leading causes of mortality across the world. There is an urgent requirement to build a robust arsenal of effective antimicrobials, targeting novel molecular mechanisms to overcome the challenges posed by the increase of antibiotic resistance in TB. Mycobacterium tuberculosis has a unique cell envelope structure and composition, containing a peptidoglycan layer that is essential for maintaining cellular integrity and for virulence. The enzymes involved in the biosynthesis, degradation, remodelling and recycling of peptidoglycan have resurfaced as attractive targets for anti-infective drug discovery. Here, we review the importance of peptidoglycan, including the structure, function and regulation of key enzymes involved in its metabolism. We also discuss known inhibitors of ATP-dependent Mur ligases, and discuss the potential for the development of pan-enzyme inhibitors targeting multiple Mur ligases.
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Chan, Jia Mun, i Joseph P. Dillard. "Neisseria gonorrhoeae Crippled Its Peptidoglycan Fragment Permease To Facilitate Toxic Peptidoglycan Monomer Release". Journal of Bacteriology 198, nr 21 (22.08.2016): 3029–40. http://dx.doi.org/10.1128/jb.00437-16.
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ABSTRACTNeisseria gonorrhoeae(gonococci) andNeisseria meningitidis(meningococci) are human pathogens that cause gonorrhea and meningococcal meningitis, respectively. BothN. gonorrhoeaeandN. meningitidisrelease a number of small peptidoglycan (PG) fragments, including proinflammatory PG monomers, althoughN. meningitidisreleases fewer PG monomers. The PG fragments released byN. gonorrhoeaeandN. meningitidisare generated in the periplasm during cell wall remodeling, and a majority of these fragments are transported into the cytoplasm by an inner membrane permease, AmpG; however, a portion of the PG fragments are released into the extracellular environment through unknown mechanisms. We previously reported that the expression of meningococcalampGinN. gonorrhoeaereduced PG monomer release by gonococci. This finding suggested that the efficiency of AmpG-mediated PG fragment recycling regulates the amount of PG fragments released into the extracellular milieu. We determined that three AmpG residues near the C-terminal end of the protein modulate AmpG's efficiency. We also investigated the association between PG fragment recycling and release in two species of human-associated nonpathogenicNeisseria:N. siccaandN. mucosa. BothN. siccaandN. mucosarelease lower levels of PG fragments and are more efficient at recycling PG fragments thanN. gonorrhoeae. Our results suggest thatN. gonorrhoeaehas evolved to increase the amounts of toxic PG fragments released by reducing its PG recycling efficiency.IMPORTANCENeisseria gonorrhoeaeandNeisseria meningitidisare human pathogens that cause highly inflammatory diseases, althoughN. meningitidisis also frequently found as a normal member of the nasopharyngeal microbiota. NonpathogenicNeisseria, such asN. siccaandN. mucosa, also colonize the nasopharynx without causing disease. Although all four species release peptidoglycan fragments,N. gonorrhoeaeis the least efficient at recycling and releases the largest amount of proinflammatory peptidoglycan monomers, partly due to differences in the recycling permease AmpG. Studying the interplay between bacterial physiology (peptidoglycan metabolism) and pathogenesis (release of toxic monomers) leads to an increased understanding of how different bacterial species maintain asymptomatic colonization or cause disease and may contribute to efforts to mitigate disease.
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Rojony, Rajoana, Lia Danelishvili, Anaamika Campeau, Jacob M. Wozniak, David J. Gonzalez i Luiz E. Bermudez. "Exposure of Mycobacterium abscessus to Environmental Stress and Clinically Used Antibiotics Reveals Common Proteome Response among Pathogenic Mycobacteria". Microorganisms 8, nr 5 (9.05.2020): 698. http://dx.doi.org/10.3390/microorganisms8050698.
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Mycobacterium abscessus subsp. abscessus (MAB) is a clinically important nontuberculous mycobacterium (NTM) causing pulmonary infection in patients such as cystic fibrosis and bronchiectasis. MAB is naturally resistant to the majority of available antibiotics. In attempts to identify the fundamental response of MAB to aerobic, anaerobic, and biofilm conditions (as it is encountered in patients) and during exposure to antibiotics, we studied bacterial proteome using tandem mass tag mass spectrometry sequencing. Numerous de novo synthesized proteins belonging to diverse metabolic pathways were found in anaerobic and biofilm conditions, including glycolysis/gluconeogenesis, tricarboxylic acid (TCA) cycle, oxidative phosphorylation, nitrogen metabolism, and glyoxylate and dicarboxylate metabolism. Upon exposure to amikacin and linezolid under stress environments, MAB displayed metabolic enrichment for glycerophospholipid metabolism and oxidative phosphorylation. By comparing proteomes of two significant NTMs, MAB and M. avium subsp. hominissuis, we found highly synthesized shared enzymes of oxidative phosphorylation, TCA cycle, glycolysis/gluconeogenesis, glyoxylate/dicarboxylate, nitrogen metabolism, peptidoglycan biosynthesis, and glycerophospholipid/glycerolipid metabolism. The activation of peptidoglycan and fatty acid biosynthesis pathways indicates the attempt of bacteria to modify the cell wall, influencing the susceptibility to antibiotics. This study establishes global changes in the synthesis of enzymes promoting the metabolic shift and enhancing the pathogen resistance to antibiotics within different environments.
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PAYIE, KENNETH G., HENRI STRATING i ANTHONY J. CLARKE. "The Role ofO-Acetylation in the Metabolism of Peptidoglycan inProvidencia stuartii". Microbial Drug Resistance 2, nr 1 (styczeń 1996): 135–40. http://dx.doi.org/10.1089/mdr.1996.2.135.
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Regulski, Krzysztof. "Influence of peptidoglycan metabolism on immunomodulatory properties of Lactobacillus casei". Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112313.
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Le peptidoglycane (PG) est le composant majeur de la paroi des bactéries à Gram positif. Il assure la forme et l’intégrité de la cellule bactérienne. Le PG ou des fragments dérivés sont connus pour être des inducteurs du système d’immunité innée de l’hôte, en particulier au travers des récepteurs Nod2. Au cours de ce travail, nous avons étudié l’influence du métabolisme du PG sur les propriétés immunomodulatrices de Lactobacillus casei BL23, en étudiant principalement sa capacité à moduler la réponse des cellules dendritiques humaines. Nous avons tout d’abord caractérisé les hydrolases du PG (PGHs) majeures de L. casei BL23. Une recherche in silico a révélé que L. casei possède un système de PGHs relativement complexe comprenant treize enzymes putatives avec des domaines catalytiques variés. Une analyse protéomique d’extraits de paroi de L. casei BL23 a permis de détecter la production de sept d’entre elles pendant la croissance bactérienne. Quatre d’entre elles ont été étudié plus en détails. La PGH la plus fortement exprimée, Lc-p75, a une activité de -D-glutamyl-L-lysyl-endopeptidase et est responsable de la séparation des cellules après division. De plus, Lc-p75 associée à la paroi est localisée au niveau des septa cellulaires. Il s’agit également de l’une des protéines majeures secrétée dans le surnageant de culture de L. casei BL23. Lc-p75 possède la particularité d’être une glycoprotéine. La PGH Lc-p40 possède un domaine CHAP doué d’une activité endopeptidase avec un site de clivage situé au niveau des ponts interpeptidiques du PG. Lc-p40 parait localisée au niveau de la paroi latérale des cellules de L. casei. Lc-p45 est une deuxième -D-glutamyl-L-lysyl-endopeptidase avec un rôle dans le maintien de la forme de la bactérie. Enfin nous avons caractérisé deux enzymes de prophages, Lc-Lys et Lc-Lys2, codée par le génome de L. casei BL23, qui possède toute deux un domaine de liaison au PG d’un nouveau type qui possède la particularité de lier spécifiquement le D-Asp amidé présent dans les ponts interpeptidiques du PG de L. casei BL23. La délétion des deux gènes qui codent pour les endopeptidases Lc-p75 et Lc-p45 chez L. casei BL23 conduit à l’absence de disaccharide dipeptide dans la structure du PG du mutant, tandis que la délétion de Lc-p75 seulement conduit à une réduction de la quantité du disaccharide-dipeptide. Ce disaccharide dipeptide est un ligand des récepteurs Nod2. Les deux mutants obtenus par délétion de Lc-p75 ou bien par délétion des deux endopeptidases ont été comparés avec la souche sauvage BL23 pour leur capacité à activer in vitro des cellules dendritiques humaines dérivées de monocytes sanguins. Suite à l’activation des cellules dendritiques par les souches de L. casei, quatre cytokines pro-inflammatoires, les interleukines IL-6, IL-8, IL-12 et le TNF- ont été produites. La quantité de chaque cytokine sécrétée en réponse aux mutants simple Lc-p75 et double Lc-p75/Lc-p45 était diminuée par rapport à celle induite par la souche sauvage L. casei BL23.En conclusion, L. casei BL23 est doté d’un équipement complexe en PGHs. Les PGHs caractérisées au cours de ce travail présentent des caractéristiques uniques et jouent un rôle important dans la division des bactéries ainsi que dans le maintien de leur morphologie. Nos résultats indiquent que la souche sauvage de L. casei Bl23 et les mutants dérivés obtenus par inactivation d’enzymes à activité endopeptidase, qui diffèrent à la fois au niveau de leur contenu enzymatique ainsi qu’au niveau de la structure de leur PG, ont des effets différents sur les cellules dendritiques humaines, avec un caractère anti-inflammatoire plus élevé pour les mutantsPeptidoglycan (PG) is the major component of the Gram-positive bacteria cell wall. It ensures bacterial cell shape and integrity. PG or PG-derived fragments have been shown to stimulate the host innate immune system, through Nod-2 receptors. In this work, we studied the influence of PG metabolism on immunomodulatory properties of Lactobacillus casei BL23, mainly its ability to modulate the response of human dendritic cells (DCs).We have first characterized the main peptidoglycan hydrolases (PGHs) of L. casei BL23. In silico search revealed that L. casei BL23 has a rather complex PGH complement including thirteen predicted PGHs with various catalytic domains. Proteomic analysis of bacterial cell wall extracts revealed the expression of seven of them during bacterial growth. We characterized four of them in details. Lc-p75 is the major PGH with a γ-D-glutamyl-L-lysyl-endopeptidase specificity and is responsible for daughter cell separation. Lc-p75 associated to the cell wall localizes at the cell septa. It is also one of the major secreted proteins of L. casei found in culture supernatant. Besides, we showed that L. casei Lc-p75 is a glycosylated protein. Lc-p40 is a PGH with a CHAP-domain endowed with endopeptidase hydrolytic specificity toward peptidoglycan cross-bridges and appears to localize on lateral cell wall. Lc-p45 is a second γ-D-glutamyl-L-lysyl endopeptidase with a role in cell shape maintenance. We further demonstrated that two prophage endolysins Lc-Lys and Lc-Lys2, encoded in L. casei BL23 genome, share a common novel type peptidoglycan-binding domain that recognizes specifically D-Asn cross-bridge, present in L. casei BL23 peptidoglycan.Deletion of the two endopeptidases, Lc-75 and Lc-p45, resulted in a complete loss ofdisaccharide-dipeptide, which is a ligand of Nod-2 receptor, in the muropeptide structure of L. casei BL23, whereas deletion of Lc-p75 gene led only to a reduction of disaccharide dipeptide. The two PGH-mutants, obtained by deletion of Lc-p75 gene alone or both Lc-p75 and Lc-p45 endopeptidase genes were compared with wild type L. casei BL23 for their capacity to stimulate signaling pathways in vitro in DCs derived from human monocytes. As a consequence of DC activation by L. casei strains, four pro-inflammatory cytokines IL-6, IL-8, IL-12 and TNF-α were produced. The concentrations of secreted cytokines in response to the single Lc-p75 and Lc-p75/p45 double mutant were lower than those induced by wild type L. casei BL23.In conclusion, L. casei BL23 has a complex PGH complement. The PGHs described in this work present unique features and play important role in cell division and morphology of L. casei. Our results indicate that wild type L. casei and endopeptidase-negative mutants, which differ in their PGH content and in their PG structure, have distinct effects on human DCs, with a higher anti-inflammatory character of the endopeptidase-negative mutants
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Veeraraghavan, Usha. "Molecular and biochemical characterisation of mycobacterial peptidoglycan biosynthesis and glycogen metabolism". Thesis, University of Birmingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522053.
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Broughton, Sarah Louise. "Studies on the metabolism and O-acetylation of peptidoglycan in Proteus mirabilis". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33213.pdf.
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Cherier, Dimitri. "CARACTERISATION BIOCHIMIQUE ET STRUCTURALE DE BACTERIOCINES CIBLANT LE METABOLISME DU PEPTIDOGLYCANE BACTERIEN, ALTERNATIVE POTENTIELLE AUX ANTIBIOTIQUES". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS529/document.
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L’émergence de bactéries multirésistantes aux antibiotiques est la conséquence de leur utilisation à mauvais escient au cours de ces dernières décennies. Ce phénomène constitue un problème de santé publique majeur, et face à cette urgence sanitaire, il est nécessaire de trouver rapidement de nouveaux agents antibactériens.Les colicines, au regard de leurs propriétés antimicrobiennes intrinsèques, constituent des candidats intéressants. Naturellement produites par E. coli dans le but de tuer des souches compétitrices de la même espèce ou d’espèces apparentées, elles exercent en général leur activité cytotoxique par le biais d’une activité ionophorique ou nucléasique. Parmi les nombreuses colicines connues à ce jour, la colicine M (ColM) est la seule à interférer avec la voie de biosynthèse du peptidoglycane, macromolécule essentielle et spécifique au monde bactérien. En effet, une fois dans le périplasme de E. coli, la ColM clive le lipide II, dernier précurseur de la voie de biosynthèse du peptidoglycane, conduisant de ce fait à la lyse bactérienne. Plusieurs homologues de la ColM ont été identifiés chez d’autres genres bactériens (Pseudomonas, Pectobacterium et Burkholderia) mais aucune cytotoxicité croisée n’a été mise en évidence à ce jour, d’où un spectre d’action restreint pour les membres de cette nouvelle famille d’enzymes antibactériennes.Ce travail traite de l’étude structurale et biochimique de la ColM et de certains de ses homologues. L’étude structurale de différents variants de la PaeM, homologue issu de P. aeruginosa, a permis d’identifier une molécule d’eau conservée au sein du site actif qui joue probablement un rôle central dans le mécanisme catalytique de cette famille d’enzyme. L’expression des homologues de la ColM issus de Pseudomonas et de Pectobacterium, directement dans le périplasme de E. coli, a permis de démontrer leur activité lytique, prouvant ainsi le grand potentiel de ces bactériocines en tant qu’alternatives aux antibiotiques. Enfin, la construction de plusieurs colicines chimères entre la ColM et ses homologues, capables de dégrader le lipide II in vitro et d’induire la lyse d’E. coli suite à leur expression périplasmique, ouvre la voie à de futurs espoirs thérapeutiquesThe misuse of antibiotics during the last decades led to the emergence of multidrug resistant pathogenic bacteria. This phenomenon constitutes a major public health issue. Given that urgency, the finding of new antibacterials in the short term is crucial.Colicins, due to their antimicrobials properties, constitute good candidates. They are protein toxins produced by E. coli to kill competitors belonging to the same or related species. In most cases, they exhibit their cytotoxic activity through an ionophoric or nucleasic activity. Among the twenty colicins known to date, colicin M (ColM) is the only one known to interfere with peptidoglycan biosynthesis. It develops its lethal activity in the E. coli periplasm, in three steps deeply linked to its structural organization in three domains. Once in the periplasm, ColM degrades the lipid II, i.e. the last precursor in the peptidoglycan biosynthesis pathway, in two products that cannot be reused, thereby leading to cell lysis. Several ColM homologues have been identified in other bacterial genera, such as Pseudomonas, Pectobacterium and Burkholderia, but no cross activity has been shown to date, explaining the narrow antibacterial spectrum displayed by the members of this new family of antibacterial enzymes.This work deals with the structural and biochemical study of ColM and some of its homologues. Structural studies on several variants of PaeM, the ColM homologue from P. aeruginosa, led to identify a conserved water molecule in the active site, probably playing a central role in the catalytic mechanism of this enzyme family. Moreover, expression of ColM homologues from Pseudomonas or Pectobacterium species directly in the E. coli periplasm showed that all these homologues were able to induce E. coli cell lysis, thus demonstrating the great potential of these bacteriocins as an alternative to antibiotics. Following these results, several chimera colicins were created between ColM and its homologues, which were shown to degrade lipid II in vitro and to induce E. coli cell lysis after their periplasmic expression, opening the way to future new therapeutic options
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Waterworth, James Stephen. "Anaerobic biodegradation of Peptidoglycan and Chitin by freshwater and marine sediment bacteria". Thesis, Queen Mary, University of London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266849.
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Le, Roux Pierre. "Recherche d'inhibiteurs et d'antibacteriques peptidiques synthetiques, ayant pour cible le metabolisme du peptidoglycane bacterien". Paris 11, 1990. http://www.theses.fr/1990PA112114.
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Ce travail s'inscrit dans le contexte d'une recherche d'inhibiteurs de la biosynthese du peptidoglycane bacterien. L'interet de tels composes reside dans le fait que toute inhibition de cette biosynthese induit un effet bacteriostatique, ou meome bactericide et que par consequent, ils sont susceptibles d'etre antibacteriens. Dans un premier temps, nous nous sommes interesses a incorporer dans des peptides l'acide 2-aminopimelique (apm), un inhibiteur de la biosynthese de l'acide meso-diaminopimelique (m-dap) constitutif du peptidoglycane. Deux peptides combinant l'apm a un autre inhibiteur de la biosynthese du peptidoglycane, la 3-chloro-l-alanine, se sont reveles etre de bons antibacteriens in vitro, pouvant meme etre dans certaines conditions de culture, bactericides. Parallelement a cette etude, nous avons entrepris la recherche d'inhibiteurs efficaces de l'enzyme d'addition du m-dap a l'udp-n-acetylmuramyl-dipeptide. En se fondant sur des analogies entre, d'une part la glutamine synthetase et la gamma-glutamyl-cysteine synthetase, et d'autre part notre enzyme, une serie de derives peptidiques devant mimer des intermediaires reactionnels, a ete preparee. Certains derives phosphoniques synthetises presentent des taux d'inhibition eleves qui laissent supposer le passage par un intermediaire acyl-phosphate au cours de la reaction enzymatique. Les concentrations en inhibiteurs relativement importantes pour obtenir ces taux d'inhibitions nous incitent a penser que l'elaboration d'inhibiteurs efficaces passe par la conception de molecules plus complexes, faisant intervenir des caracteristiques structurales plus proches du substrat naturel
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Dai, Dexi. "Five new genetic loci involved in cell wall peptidoglycan metabolism of Escherichia coli". Thesis, 1990. https://dspace.library.uvic.ca//handle/1828/9479.
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Five new genes apparently involved in the metabolism of cell wall peptidoglycan by Escherichia coli are described. One of these, designated murH, was mapped at 99 min on the E. coli linkage map. The murH1 mutant exhibited temperature- sensitive (ts) growth which was associated with a block in a late step in peptidoglycan synthesis and with peptidoglycan hydrolase-mediated lysis at the restrictive temperature. The murH locus could not be cloned in multicopy vectors but was readily cloned in a single copy phasmid vector derived from phage λ. The instability of murH in multicopy prevented its further characterization. As an alternative approach to characterizing the murH function, extragenic mutations which suppressed the murH1 ts lysis phenotype were isolated. One suppressor mutation, designated smh-A1, (25 min on the genetic linkage map) restored temperature resistance in murH1 mutants but otherwise had no distinguishable phenotype. A second extragenic murH1 suppressor, smhB1 (13 min) conferred a ts lysis phenotype by itself. Interestingly, a combination of murH1 and smhB1 resulted in cosuppression of their lysis phenotypes. The suppressor activities of the smhA1 and smhB1 alleles were relatively specific in that they failed to suppress lysis caused by either mutational (murE or murF) or antibiotic-induced blocks in peptidoglycan synthesis. Two additional ts lysis mutations, lytD1 (mapped at 13 min) and lytE1 (25 min), arose spontaneously in smhB1 and smhA1 backgrounds, respectively. The smhA1 allele suppressed the lysis phenotype of lytE1 but not of lytD1. Furthermore, the combination of smhB1 with either lytD1 or lytE1 resulted in cosuppression of their lysis phenotype. The specificity of the suppressor activities, combined with the similarities in the phenotypes of the mutants representing this collection of loci, suggested functional relationships between the murH, smhA, smhB, lytD, and lytE loci. Four clones which complemented the lytD1 mutation were obtained by screening an E. coli gene library, but it is shown that the complementing activity did not represent the E. coli chromosomal lytD locus. It is shown instead that 2 phage λ genes, identified as cro and cI, accounted for the lytD1 complementing activities in these clones. Evidence is presented which suggests that these clones were derived from phage λ DNA which was fortuitously present as a contaminant in the vector preparation used for construction of the gene library. Since the λ Cro and CI proteins are DNA-binding proteins which bind to identical 17 base-pair recognition sequences (the λ right operator sequences), it is hypothesized that LytD encodes a DNA-binding protein with a similar specificity (i.e., which binds to a λ right operator-like sequence) which regulates, probably negatively, the expression of a gene(s) involved in some way with peptidoglycan hydrolysis.Graduate
Książki na temat "Peptidoglycan metabolism"
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A, De pedro M., Höltje J. V. 1941-, Löffelhardt W i Federation of European Microbiological Societies., red. Bacterial growth and lysis: Metabolism and structure of the bacterial sacculus. New York: Plenum Press, 1993.
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E, Vance Dennis, i Vance Jean E, red. Biochemistry of lipids, lipoproteins, and membranes. Amsterdam: Elsevier, 1991.
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M.A. de Pedro (Editor), J. V. Höltje (Editor) i Wolfgang Löffelhardt (Editor), red. Bacterial Growth & Lysis: Metabolism and Structure of the Bacterial Sacculus. Springer, 1993.
Znajdź pełny tekst źródłaCzęści książek na temat "Peptidoglycan metabolism"
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van Heijenoort, Jean, Dominique Mengin-Lecreulx, Yveline van Heijenoort, Didier Blanot, Bernard Flouret, Catherine Michaud, Claudine Parquet, Flore Pratviel-Sosa, Manolo Gomez i Juan A. Ayala. "Variations in the Metabolism of Peptidoglycan Prior to Polymerization". W Bacterial Growth and Lysis, 127–38. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4757-9359-8_15.
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Tomasić, J., Z. Valinger, I. Hrsak i B. Ladesić. "Metabolic Fate of Peptidoglycan Monomer from Brevibacterium divaricatum and Biological Activity of its Metabolites". W Biological Properties of Peptidoglycan, redaktorzy Peter H. Seidl i Karl H. Schleifer, 203–8. Berlin, Boston: De Gruyter, 1986. http://dx.doi.org/10.1515/9783110874297-026.
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Seidl, P. H., i K. H. Schleifer. "SECRETION OF FRAGMENTS FROM BACTERIAL CELL WALL PEPTIDOGLYCAN". W Environmental Regulation of Microbial Metabolism, 443–50. Elsevier, 1985. http://dx.doi.org/10.1016/b978-0-12-428580-4.50050-2.
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Battistuzzi, Fabia U., i S. Blair Hedges. "Archaebacteria". W The Timetree of Life, 101–5. Oxford University PressOxford, 2009. http://dx.doi.org/10.1093/oso/9780199535033.003.0006.
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Abstract Extremophiles are common among species in the Super kingdom Archaebacteria (also called “Archaea”, Fig. 1) (1). For example, the species referred to as “Strain 121” can survive temperatures up to 121°C, higher than any other organism (2), and hyperacidophiles are found in the Family thermoplasmataceae, where two species (Picrophilus oshimae and Picrophilus torridus) are the only known organisms capable of living at a pH as low as zero (3, 4). Archaebacteria show many other phenotypes including the unique ability to produce methane (methanogenesis). 7ey have cell wall structures formed either by pseudopeptidoglycan (i.e., a material similar to the peptidoglycan of eubacteria), polysaccharides, or glycoproteins (S-layer) (5), which resemble the single-layer structure (i.e., cell membrane plus cell wall) present in gram-positive eubacteria. Furthermore, archaebacteria have a unique cell membrane structure composed of ether-linked glycerol diethers or tetraethers that confer a higher stability to extreme conditions (5). Chemotrophy is the most widely used metabolism, although phototrophic members of the Halobacteriaceae can use light to produce ATP (6). Six families also have the unique ability of obtaining energy by combining carbon dioxide (or other carbon compounds) and hydrogen into methane (5).
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BHAGAVAN, N. V. "Carbohydrate Metabolism III: Glycoproteins, Glycolipids, GPI Anchors, Proteoglycans, and Peptidoglycans". W Medical Biochemistry, 307–30. Elsevier, 2002. http://dx.doi.org/10.1016/b978-012095440-7/50018-4.
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"Postbiotics: A comprehensive Review of Classification, Application and Health Benefits". W Prospective Research and Technological Advancements in Food and Health Sciences, 361–407. Skyfox Publishing Group, 2023. http://dx.doi.org/10.22573/spg.023.978-93-90357-07-9/13.
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Postbiotics are a novel class of biologically active compounds produced during the fermentation of probiotics. Unlike probiotics, which are live microorganisms, postbiotics are non-viable bacterial components, such as cell wall fragments, peptidoglycans, teichoic acids, and metabolites. Recent studies have highlighted the beneficial effects of postbiotics on gut health, immunity, anti-inflammatory, immunomodulatory, and antioxidant effects, may improve gut barrier function and metabolic health. Postbiotics have been shown to modulate the gut microbiome, enhance intestinal barrier function and promote the growth of beneficial bacteria. Postbiotics can be derived from various sources, including bacteria, yeast, fungi, and plants, and may have potential therapeutic applications in preventing and treating various diseases. Moreover, postbiotics have been proposed as a safe and effective alternative to probiotics, particularly for individuals who cannot tolerate live bacteria. This review summarizes the current knowledge on postbiotics, their potential health benefits, and their applications in food.
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Emmett, Stevan R., Nicola Hill i Federico Dajas-Bailador. "Infectious disease". W Clinical Pharmacology for Prescribing. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780199694938.003.0019.
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Antibiotics include an extensive range of agents able to kill or prevent reproduction of bacteria in the body, without being overly toxic to the patient. Traditionally derived from living organisms, most are now chemically synthesized and act to disrupt the integrity of the bacterial cell wall, or penetrate the cell and disrupt protein synthesis or nucleic acid replication. Typically, bacteria are identified according to their appearance under the microscope depending on shape and response to the Gram stain test. Further identification is obtained by growth characteristics on various types of culture media, based on broth or agar, biochemical and immunological profiles. Further testing on broth or agar determines antibiotic sensitivity to guide on antibiotic therapy in individual patients. This process can take 24– 48 hours to culture and a further 24– 48 hours to measure sensitivities. Increasingly, new technology, e.g. Matrix Assisted Laser Desorption Ionization— Time of Flight (MALDI- TOF) and nucleic acid amplification assays, are being used to provide more rapid identification. The Gram classification, however, is still widely referred to as it differentiates bacteria by the presence or absence of the outer lipid membrane (see Figure 11.1), a fundamental characteristic that influences antibiotic management. Antimicrobial agents rely on selective action exploiting genetic differences between bacterial and eukaryotic cells. They target bacterial cell wall synthesis, bacterial protein synthesis, microbial DNA or RNA synthesis, by acting on bacterial cell metabolic pathways or by inhibiting the action of a bacterial toxin (see Table 11.1). Both Gram- positive and Gram- negative bacteria possess a rigid cell wall able to protect the bacteria from varying osmotic pressures (Figure 11.1). Peptidoglycan gives the cell wall its rigidity and is composed of a glycan chain of complex alternating carbohydrates, N- acetylglucosamide (N- ATG), and N- acetylmurcarinic acid (N- ATM), that are cross- linked by peptide (or glycine) chains. In Gram-positive bacteria, the cell wall contains multiple peptidoglycan layers, interspersed with teichoic acids, whereas Gram- negative bacteria contain only one or two peptidoglycan layers that are surrounded by an outer membrane attached by lipoproteins. The outer membrane contains porins (which regulate transport of substances into and out of the cell), lipopolysaccharides, and outer proteins in a phospholipid bilayer. For both Gram- negative and Gram-positive bacteria, peptidoglycan synthesis involves about 30 bacterial enzymes acting over three stages. Since the cell wall is unique to bacteria, it makes a suitable target for antibiotic therapy.
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Bakar, Elvan, Nebiye Pelin Türker i Zeynep Erim. "Biosynthesis and Function of Glycoconjugates". W Recent Progress in Pharmaceutical Nanobiotechnology: A Medical Perspective, 166–222. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815179422123080009.
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Investigations to ascertain the physiological roles of carbohydrates in biological systems are being given more importance each day. Basically, carbohydrates are biomolecules with a wide range of biological functions, although they represent the primary energy source for metabolic processes. Carbohydrates are found as structural components in connective tissue in animal organisms. They also act as structural elements in both plant and bacterial cell walls. In the cell, they bind to lipids and proteins to form glycoconjugates called glycolipids, glycopeptides, glycoproteins and peptidoglycans. By binding to lipids and proteins on the cell surface, they perform as molecules that support intercellular adhesion and intercellular communication. Glycobiology is the science that investigates the structure, biosynthesis, and impacts of glycans on biological functions. In biology, glycoconjugates serve a variety of key roles. In mammalian cells, the majority of proteins are glycosylated, and this explains how proteins perform their various functions. In the future, these techniques will be crucial for the identification and treatment of specific diseases. The most major area of progress in glycobiology is the development of carbohydrate-based medicines. Some diseases, including cancer, can be diagnosed via altered cell surface glycosylation pathways as a biomarker. Therefore, regulating glycosylation mechanisms and understanding the phenotypic characteristics of glycoconjugates are crucial steps in the design of novel strategies. This chapter discusses the biosynthesis of glycoconjugates, their wide range of biological functions, and their significance for therapy