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5 results on '"lysozyme sensitivity"'

1. AsnB Mediates Amidation of Meso -Diaminopimelic Acid Residues in the Peptidoglycan of Listeria monocytogenes and Affects Bacterial Surface Properties and Host Cell Invasion.

Author

Sun, Lei, Rogiers, Gil, Courtin, Pascal, Chapot-Chartier, Marie-Pierre, Bierne, Hélène, and Michiels, Chris W.

Subjects
BACTERIAL cell surfaces, AMIDATION, SURFACE properties, LISTERIA monocytogenes, BACTERIAL cell walls, GRAM-positive bacteria, SEQUENCE alignment, LISTERIOSIS
Abstract

A mutant of Listeria monocytogenes ScottA with a transposon in the 5' untranslated region of the asnB gene was identified to be hypersensitive to the antimicrobial t -cinnamaldehyde. Here, we report the functional characterization of AsnB in peptidoglycan (PG) modification and intracellular infection. While AsnB of Listeria is annotated as a glutamine-dependent asparagine synthase, sequence alignment showed that this protein is closely related to a subset of homologs that catalyze the amidation of meso -diaminopimelic acid (m DAP) residues in the peptidoglycan of other bacterial species. Structural analysis of peptidoglycan from an asnB mutant, compared to that of isogenic wild-type (WT) and complemented mutant strains, confirmed that AsnB mediates m DAP amidation in L. monocytogenes. Deficiency in m DAP amidation caused several peptidoglycan- and cell surface-related phenotypes in the asnB mutant, including formation of shorter but thicker cells, susceptibility to lysozyme, loss of flagellation and motility, and a strong reduction in biofilm formation. In addition, the mutant showed reduced invasion of human epithelial JEG-3 and Caco-2 cells. Analysis by immunofluorescence microscopy revealed that asnB inactivation abrogated the proper display at the listerial surface of the invasion protein InlA, which normally gets cross-linked to m DAP via its LPXTG motif. Together, this work shows that AsnB of L. monocytogenes , like several of its homologs in related Gram-positive bacteria, mediates the amidation of m DAP residues in the peptidoglycan and, in this way, affects several cell wall and cell surface-related properties. It also for the first time implicates the amidation of peptidoglycan m DAP residues in cell wall anchoring of InlA and in bacterial virulence. [ABSTRACT FROM AUTHOR]

Published
2021
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2. A multiple comparative study of putative endosymbionts in three coexisting apple snail species.

Author

Dellagnola, Federico A., Rodriguez, Cristian, Castro-Vazquez, Alfredo, and Vega, Israel A.

Subjects
POMACEA canaliculata, PYRAMIDAL neurons, SNAILS, SPECIES, CELL membranes, BACTERIAL cell walls, MOLECULAR phylogeny
Abstract

We here compare morphological and molecular characters of some putative endosymbiotic elements of the digestive gland of three ampullariid species (Pomacea canaliculata, Pomacea scalaris and Asolene platae) which coexist in Lake Regatas (Palermo, Buenos Aires). The putative endosymbionts were reported in these species and were identified as C and K corpuscles. The three species show tubuloacinar glands, each adenomere was constituted mainly by two distinct cell types (columnar and pyramidal). C and K corpuscles together occupied from one-fourth to one-fifth of the tissue area in the three host species, where C corpuscles were round and greenish-brown, were delimited by a distinct wall, stained positively with Alcian Blue and were associated with columnar cells. K corpuscles were oval, dark-brown multilamellar bodies and were associated with pyramidal cells. Under TEM, C corpuscles occurred within vacuoles of columnar cells and contained many electron-dense clumps and irregular membrane stacks and vesicles spread in an electron-lucent matrix. Sometimes a membrane appeared detached from the inner surface of the wall, suggesting the existence of a plasma membrane. In turn, K corpuscles were contained within vacuoles of pyramidal cells and were made of concentric lamellae, which were in turn made of an electron-dense fibrogranular material. No membranes were seen in them. Interspecifically, C corpuscles vary significantly in width and inner contents. K corpuscles were also variable in length and width. However, both C and K corpuscles in the three studied species hybridised with generalised cyanobacterial/chloroplast probes for 16S rRNA. Also, both corpuscle types (isolated from gland homogenates) were sensitive to lysozyme digestion, which indicates that bacterial peptidoglycans are an integral part of their covers. The reported data confirm and extend previous studies on P. canaliculata in which the endosymbiotic nature of C and K corpuscles were first proposed. We further propose that the endosymbiotic corpuscles are related to the Cyanobacteria/chloroplasts clade. Based on the known distribution of these corpuscles in the major clades of Ampullariidae, we hypothesise they may be universally distributed in this family, and that may constitute an interesting model for studying the co-evolution of endosymbionts and their gastropod hosts. [ABSTRACT FROM AUTHOR]

Published
2019
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3. Polysaccharide deacetylases serve as new targets for the design of inhibitors against Bacillus anthracis and Bacillus cereus.

Author

Balomenou, Stavroula, Koutsioulis, Dimitris, Tomatsidou, Anastasia, Tzanodaskalaki, Mary, Petratos, Kyriacos, and Bouriotis, Vassilis

Subjects
*POLYSACCHARIDES, *BACILLUS anthracis, *BACILLUS cereus, *PEPTIDOGLYCANS, *DEACETYLASES
Abstract

Peptidoglycan N -acetylglucosamine (GlcNAc) deacetylases (PGNGdacs) from bacterial pathogens are validated targets for the development of novel antimicrobial agents. In this study we examined the in vitro inhibition of hydroxamate ligand N -hydroxy-4-(naphthalene-1-yl)benzamide (NHNB), a selective inhibitor of histone deacetylases-8 (HDAC8), against two PGNGdacs namely BC1974 and BC1960 from B. cereus , highly homologous to BA1977 and BA1961 of B. anthracis , respectively. Kinetic analysis showed that this compound functions as a competitive inhibitor of both enzymes with apparent K i ’s of 8.7 μM (for BC1974) and 66 μM (for BC1960), providing thus the most potent CE4 inhibitor reported to date. NHNB was tested in antibacterial assays and showed bactericidal activity against both examined pathogens acting as a multi-target drug. This compound can serve as lead for the development of inhibitors targeting the conserved active sites of the multiple polysaccharide deacetylases (PDAs) of both pathogens. [ABSTRACT FROM AUTHOR]

Published
2018
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4. AsnB Mediates Amidation of Meso-Diaminopimelic Acid Residues in the Peptidoglycan of Listeria monocytogenes and Affects Bacterial Surface Properties and Host Cell Invasion

Author

Marie-Pierre Chapot-Chartier, Lei Sun, Hélène Bierne, Chris W. Michiels, Gil Rogiers, and Pascal Courtin

Subjects
Microbiology (medical), lysozyme sensitivity, Mutant, Virulence, Sequence alignment, medicine.disease_cause, Microbiology, peptidoglycan modification, Cell wall, chemistry.chemical_compound, Listeria monocytogenes, meso-diaminopimelic acid, medicine, host cell invasion, Original Research, biology, biology.organism_classification, QR1-502, virulence, chemistry, Biochemistry, motility, biofilm formation, Peptidoglycan, Lysozyme, Bacteria
Abstract

A mutant of Listeria monocytogenes ScottA with a transposon in the 5' untranslated region of the asnB gene was identified to be hypersensitive to the antimicrobial t-cinnamaldehyde. Here, we report the functional characterization of AsnB in peptidoglycan (PG) modification and intracellular infection. While AsnB of Listeria is annotated as a glutamine-dependent asparagine synthase, sequence alignment showed that this protein is closely related to a subset of homologs that catalyze the amidation of meso-diaminopimelic acid (mDAP) residues in the peptidoglycan of other bacterial species. Structural analysis of peptidoglycan from an asnB mutant, compared to that of isogenic wild-type (WT) and complemented mutant strains, confirmed that AsnB mediates mDAP amidation in L. monocytogenes. Deficiency in mDAP amidation caused several peptidoglycan- and cell surface-related phenotypes in the asnB mutant, including formation of shorter but thicker cells, susceptibility to lysozyme, loss of flagellation and motility, and a strong reduction in biofilm formation. In addition, the mutant showed reduced invasion of human epithelial JEG-3 and Caco-2 cells. Analysis by immunofluorescence microscopy revealed that asnB inactivation abrogated the proper display at the listerial surface of the invasion protein InlA, which normally gets cross-linked to mDAP via its LPXTG motif. Together, this work shows that AsnB of L. monocytogenes, like several of its homologs in related Gram-positive bacteria, mediates the amidation of mDAP residues in the peptidoglycan and, in this way, affects several cell wall and cell surface-related properties. It also for the first time implicates the amidation of peptidoglycan mDAP residues in cell wall anchoring of InlA and in bacterial virulence.

Published
2021

5. A multiple comparative study of putative endosymbionts in three coexisting apple snail species

Author

Cristian Rodriguez, Alfredo Castro-Vazquez, Federico A. Dellagnola, and Israel A. Vega

Subjects
0106 biological sciences, lcsh:Medicine, Vacuole, Columnar Cell, 010501 environmental sciences, Freshwater Biology, Intracellular bacteria, 01 natural sciences, purl.org/becyt/ford/1 [https], Digestive gland, Pomacea, biology, Endosymbiosis, Chemistry, General Neuroscience, General Medicine, Evolutionary Studies, Chloroplast, Adenomere, LYSOZYME SENSITIVITY, Asolene, Lysozyme sensitivity, Otros Tópicos Biológicos, General Agricultural and Biological Sciences, Pomacea canaliculata, CIENCIAS NATURALES Y EXACTAS, Histology, AMPULLARIIDAE, ASOLENE, ENDOSYMBIOSIS, 010603 evolutionary biology, General Biochemistry, Genetics and Molecular Biology, Ciencias Biológicas, DIGESTIVE GLAND, FISH, 16S rRNA, Ampullariidae, purl.org/becyt/ford/1.6 [https], 0105 earth and related environmental sciences, Morphometry, COEVOLUTION, lcsh:R, biology.organism_classification, POMACEA, Molecular biology, INTRACELLULAR BACTERIA, MORPHOMETRY, Fluorescence in situ hybridisation, Zoology, Coevolution
Abstract

We here compare morphological and molecular characters of some putative endosymbioticelements of the digestive gland of three ampullariid species (Pomacea canaliculata,Pomacea scalaris and Asolene platae) which coexist in Lake Regatas (Palermo, BuenosAires). The putative endosymbionts were reported in these species and were identifiedas C and K corpuscles. The three species show tubuloacinar glands, each adenomerewas constituted mainly by two distinct cell types (columnar and pyramidal). C and Kcorpuscles together occupied from one-fourth to one-fifth of the tissue area in the threehost species, where C corpuscles were round and greenish-brown, were delimited bya distinct wall, stained positively with Alcian Blue and were associated with columnarcells. K corpuscles were oval, dark-brown multilamellar bodies and were associatedwith pyramidal cells. Under TEM, C corpuscles occurred within vacuoles of columnarcells and contained many electron-dense clumps and irregular membrane stacks andvesicles spread in an electron-lucent matrix. Sometimes a membrane appeared detachedfrom the inner surface of the wall, suggesting the existence of a plasma membrane. Inturn, K corpuscles were contained within vacuoles of pyramidal cells and were madeof concentric lamellae, which were in turn made of an electron-dense fibrogranularmaterial. No membranes were seen in them. Interspecifically, C corpuscles varysignificantly in width and inner contents. K corpuscles were also variable in lengthand width. However, both C and K corpuscles in the three studied species hybridisedwith generalised cyanobacterial/chloroplast probes for 16S rRNA. Also, both corpuscletypes (isolated from gland homogenates) were sensitive to lysozyme digestion, whichindicates that bacterial peptidoglycans are an integral part of their covers. The reporteddata confirm and extend previous studies on P. canaliculata in which the endosymbioticnature of C and K corpuscles were first proposed. We further propose that theendosymbiotic corpuscles are related to the Cyanobacteria/chloroplasts clade. Basedon the known distribution of these corpuscles in the major clades of Ampullariidae,we hypothesise they may be universally distributed in this family, and that mayconstitute an interesting model for studying the co-evolution of endosymbionts andtheir gastropod hosts. Fil: Dell Agnola, Federico Agustín. Universidad Nacional de Cuyo. Facultad de Ciencias Medicas. Instituto de Fisiologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina Fil: Rodríguez, Cristian. Universidad Nacional de Cuyo. Facultad de Ciencias Medicas. Instituto de Fisiologia; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina Fil: Castro Vazquez, Alfredo Juan. Universidad Nacional de Cuyo. Facultad de Ciencias Medicas. Instituto de Fisiologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina Fil: Vega, Israel Aníbal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Medicas. Instituto de Fisiologia; Argentina

Published
2019

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