scholarly journals Cell Wall Alterations of Gram-Negative Bacteria by Aminoglycoside Antibiotics

1974 ◽  
Vol 5 (1) ◽  
pp. 95-97 ◽  
Author(s):  
K. Iida ◽  
M. Koike
Keyword(s):  
Cell Wall ◽  
Aminoglycoside Antibiotics ◽  
Gram Negative Bacteria ◽  
Gram Negative

scholarly journals Gram-positive bacteria cell wall-derived lipoteichoic acid induces inflammatory alveolar bone loss through prostaglandin E production in osteoblasts

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsukasa Tominari ◽  
Ayumi Sanada ◽  
Ryota Ichimaru ◽  
Chiho Matsumoto ◽  
Michiko Hirata ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bone Loss ◽  
Alveolar Bone ◽  
Osteoclast Differentiation ◽  
Lipoteichoic Acid ◽  
Alveolar Bone Loss ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

AbstractPeriodontitis is an inflammatory disease associated with severe alveolar bone loss and is dominantly induced by lipopolysaccharide from Gram-negative bacteria; however, the role of Gram-positive bacteria in periodontal bone resorption remains unclear. In this study, we examined the effects of lipoteichoic acid (LTA), a major cell-wall factor of Gram-positive bacteria, on the progression of inflammatory alveolar bone loss in a model of periodontitis. In coculture of mouse primary osteoblasts and bone marrow cells, LTA induced osteoclast differentiation in a dose-dependent manner. LTA enhanced the production of PGE2 accompanying the upregulation of the mRNA expression of mPGES-1, COX-2 and RANKL in osteoblasts. The addition of indomethacin effectively blocked the LTA-induced osteoclast differentiation by suppressing the production of PGE2. Using ex vivo organ cultures of mouse alveolar bone, we found that LTA induced alveolar bone resorption and that this was suppressed by indomethacin. In an experimental model of periodontitis, LTA was locally injected into the mouse lower gingiva, and we clearly detected alveolar bone destruction using 3D-μCT. We herein demonstrate a new concept indicating that Gram-positive bacteria in addition to Gram-negative bacteria are associated with the progression of periodontal bone loss.

scholarly journals General principles for the formation and proliferation of a wall-free (L-form) state in bacteria

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Romain Mercier ◽  
Yoshikazu Kawai ◽  
Jeff Errington
Keyword(s):  
Cell Wall ◽  
Molecular Biology ◽  
Gram Negative Bacteria ◽  
Systematic Analysis ◽  
Gram Negative ◽  
Membrane Blebbing ◽  
Precursor Synthesis ◽  
Peptidoglycan Cell Wall ◽  
Synthetic Cells ◽  
Opening Up

The peptidoglycan cell wall is a defining structural feature of the bacterial kingdom. Curiously, some bacteria have the ability to switch to a wall-free or ‘L-form’ state. Although known for decades, the general properties of L-forms are poorly understood, largely due to the lack of systematic analysis of L-forms in the molecular biology era. Here we show that inhibition of peptidoglycan precursor synthesis promotes the generation of L-forms from both Gram-positive and Gram-negative bacteria. We show that the L-forms generated have in common a mechanism of proliferation involving membrane blebbing and tubulation, which is dependent on an altered rate of membrane synthesis. Crucially, this mode of proliferation is independent of the essential FtsZ based division machinery. Our results suggest that the L-form mode of proliferation is conserved across the bacterial kingdom, reinforcing the idea that it could have been used in primitive cells, and opening up its use in the generation of synthetic cells.

Select Gram-negative Aerobic Bacteria

2012 ◽  
pp. 90-101
Author(s):  
David R. McNamara ◽  
Franklin R. Cockerill
Keyword(s):  
Cell Wall ◽  
Sepsis Syndrome ◽  
Vital Role ◽  
Klebsiella Pneumonia ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Neisseria Meningitides ◽  
A Cell ◽  
Normal Human ◽  
Specific Species

Gram-negative bacteria may be rod-shaped (bacilli), spherical (cocci), oval, helical, or filamentous. Cytoplasmic membrane is surrounded by a cell wall consisting of a peptidoglycan layer and an outer cell membrane. Gram-negative bacteria are widely distributed in the natural environment. They are commensals with many animals and play a vital role in normal human physiology as intestinal commensals. Gram-negative bacteria are the cause of various human illnesses. The gram-negative bacterial cell wall contains various lipopolysaccharide endotoxins. Endotoxins trigger intense inflammation and the sepsis syndrome during infection. Specific species of gram-negative bacteria such as Neisseria meningitides, Moraxella catarrhalis, Acinetobacter, Vibrio, Klebsiella pneumonia, Salmonella, Pseudomonas aeruginosa, and Haemophilus influenza are reviewed.

scholarly journals Discovery of Salmonella trehalose phospholipids reveals functional convergence with mycobacteria

2019 ◽  
Vol 216 (4) ◽  
pp. 757-771 ◽  
Author(s):  
Peter Reinink ◽  
Jeffrey Buter ◽  
Vivek K. Mishra ◽  
Eri Ishikawa ◽  
Tan-Yun Cheng ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacterial Species ◽  
Specific Cell ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Trehalose Dimycolate ◽  
Functional Convergence ◽  
Cord Factor ◽  
Cardiolipin Synthase ◽  
Activating Receptor

Salmonella species are among the world’s most prevalent pathogens. Because the cell wall interfaces with the host, we designed a lipidomics approach to reveal pathogen-specific cell wall compounds. Among the molecules differentially expressed between Salmonella Paratyphi and S. Typhi, we focused on lipids that are enriched in S. Typhi, because it causes typhoid fever. We discovered a previously unknown family of trehalose phospholipids, 6,6′-diphosphatidyltrehalose (diPT) and 6-phosphatidyltrehalose (PT). Cardiolipin synthase B (ClsB) is essential for PT and diPT but not for cardiolipin biosynthesis. Chemotyping outperformed clsB homology analysis in evaluating synthesis of diPT. DiPT is restricted to a subset of Gram-negative bacteria: large amounts are produced by S. Typhi, lower amounts by other pathogens, and variable amounts by Escherichia coli strains. DiPT activates Mincle, a macrophage activating receptor that also recognizes mycobacterial cord factor (6,6′-trehalose dimycolate). Thus, Gram-negative bacteria show convergent function with mycobacteria. Overall, we discovered a previously unknown immunostimulant that is selectively expressed among medically important bacterial species.

scholarly journals Helicobacter pylori Peptidoglycan Modifications Confer Lysozyme Resistance and Contribute to Survival in the Host

mBio ◽  
2012 ◽  
Vol 3 (6) ◽  
Author(s):  
Ge Wang ◽  
Leja F. Lo ◽  
Lennart S. Forsberg ◽  
Robert J. Maier
Keyword(s):  
Cell Wall ◽  
Helicobacter Pylori ◽  
Double Mutant ◽  
Lytic Enzyme ◽  
Permeability Barrier ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
H Pylori ◽  
Modification Enzyme

ABSTRACTThe prominent host muramidase lysozyme cleaves bacterial peptidoglycan (PG), and the enzyme is abundant in mucosal secretions. The lytic enzyme susceptibility of Gram-negative bacteria and mechanisms they use to thwart lytic enzyme activity are poorly studied. We previously characterized aHelicobacter pyloriPG modification enzyme, an N-deacetylase (PgdA) involved in lysozyme resistance. In this study, another PG modification enzyme, a putative PG O-acetyltransferase (PatA), was identified. Mass spectral analysis of the purified PG demonstrated that apatAstrain contained a greatly reduced amount of acetylated muropeptides, indicating a role for PatA inH. pyloriPG O-acetylation. The PG modification mutant strains (pgdA,patA, orpgdA patA) were more susceptible to lysozyme killing than the parent, but this assay required high lysozyme levels (up to 50 mg/ml). However, addition of host lactoferrin conferred lysozyme sensitivity toH. pylori, at physiologically relevant concentrations of both host components (3 mg/ml lactoferrin plus 0.3 mg/ml lysozyme). ThepgdA patAdouble mutant strain was far more susceptible to lysozyme/lactoferrin killing than the parent. Peptidoglycan purified from apgdA patAmutant was five times more sensitive to lysozyme than PG from the parent strain, while PG from both single mutants displayed intermediate sensitivity. Both sensitivity assays for whole cells and for purified PGs indicated that the modifications mediated by PgdA and PatA have a synergistic effect, conferring lysozyme tolerance. In a mouse infection model, significant colonization deficiency was observed for the double mutant at 3 weeks postinoculation. The results show that PG modifications affect the survival of a Gram-negative pathogen.IMPORTANCEPathogenic bacteria evade host antibacterial enzymes by a variety of mechanisms, which include resisting lytic enzymes abundant in the host. Enzymatic modifications to peptidoglycan (PG, the site of action of lysozyme) are a known mechanism used by Gram-positive bacteria to protect against host lysozyme attack. However, Gram-negative bacteria contain a thin layer of PG and a recalcitrant outer membrane permeability barrier to resist lysis, so molecular modifications to cell wall structure in order to combat lysis remain largely unstudied. Here we show that twoHelicobacter pyloriPG modification enzymes (PgdA and PatA) confer a clear protective advantage to a Gram-negative bacterium. They protect the bacterium from lytic enzyme degradation, albeit via different PG modification activities. Many pathogens are Gram negative, so some would be expected to have a similar cell wall-modifying strategy. Understanding such strategies may be useful for combating pathogen growth.

LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

1966 ◽  
Vol 12 (1) ◽  
pp. 105-108 ◽  
Author(s):  
K. Jane Carson ◽  
R. G. Eagon
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Gram Negative Bacteria ◽  
Normal Cells ◽  
Thin Sections ◽  
Gram Negative ◽  
Cell Wall Rigidity

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.

scholarly journals The ColM Family, Polymorphic Toxins Breaching the Bacterial Cell Wall

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Maarten G. K. Ghequire ◽  
Susan K. Buchanan ◽  
René De Mot
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Cytoplasmic Membrane ◽  
Catalytic Domain ◽  
Gram Negative Bacteria ◽  
Antibacterial Peptides ◽  
Gram Negative ◽  
Lipid Ii ◽  
Associated Proteins ◽  
Colicin M

ABSTRACT Bacteria host an arsenal of antagonism-mediating molecules to combat for ecologic space. Bacteriocins represent a pivotal group of secreted antibacterial peptides and proteins assisting in this fight, mainly eliminating relatives. Colicin M, a model for peptidoglycan-interfering bacteriocins in Gram-negative bacteria, appears to be part of a set of polymorphic toxins equipped with such a catalytic domain (ColM) targeting lipid II. Diversifying recombination has enabled parasitism of different receptors and has also given rise to hybrid bacteriocins in which ColM is associated with another toxin module. Remarkably, ColM toxins have recruited a diverse array of immunity partners, comprising cytoplasmic membrane-associated proteins with different topologies. Together, these findings suggest that different immunity mechanisms have evolved for ColM, in contrast to bacteriocins with nuclease activities.

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