scholarly journals Glucosamine Found as a Substituent of Both Phosphate Groups in Bordetella Lipid A Backbones: Role of a BvgAS-Activated ArnT Ortholog

2008 ◽  
Vol 190 (12) ◽  
pp. 4281-4290 ◽  
Author(s):  
Nico Marr ◽  
Alina Tirsoaga ◽  
Didier Blanot ◽  
Rachel Fernandez ◽  
Martine Caroff
Keyword(s):  
Lipid A ◽  
Biological Activities ◽  
Antigenic Determinants ◽  
Gram Negative Bacteria ◽  
Core Oligosaccharide ◽  
Gene Encoding ◽  
Gram Negative ◽  
Host Immune Responses ◽  
Covalently Linked ◽  
Phosphate Groups

ABSTRACT Endotoxins are amphipathic lipopolysaccharides (LPSs), major constituents of the outer membrane of gram-negative bacteria. They consist of a lipid region, covalently linked to a core oligosaccharide, to which may be linked a repetitive glycosidic chain carrying antigenic determinants. Most of the biological activities of endotoxins have been associated with the lipid moiety of the molecule: unique to gram-negative bacteria, LPS is a ligand of the mammalian TLR4-MD2-CD14 pathogen recognition receptor complex. Lipid A preparations are often heterogeneous with respect to both the numbers and the lengths of fatty acids and the natures of substituents on the phosphate groups when present. The variants can significantly affect host immune responses. Nine species in the Bordetella genus have been described, and the fine LPS structures of seven of them have been published. In this report, lipids A from Bordetella pertussis Tohama I and B. bronchiseptica strain 4650 were further characterized and revealed to have a glucosamine substituting both lipid A phosphate groups of the diglucosamine backbone. These substitutions have not been previously described for bordetellae. Moreover, a B. pertussis transposon mutation that maps within a gene encoding a Bordetella ArnT (formerly PmrK) glycosyl transferase ortholog does not carry this substitution, thus providing a genetic basis for the modification. Reverse transcriptase PCR of this locus showed that it is Bvg regulated, suggesting that the ability of Bordetella to modify lipid A via this glucosamine modification is a potential virulence trait.

scholarly journals Complete Lipooligosaccharide Structure from Pseudoalteromonas nigrifaciens Sq02-Rifr and Study of Its Immunomodulatory Activity

Marine Drugs ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. 646
Author(s):  
Rossella Di Guida ◽  
Angela Casillo ◽  
Antonietta Stellavato ◽  
Celeste Di Meo ◽  
Soichiro Kawai ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Lipid A ◽  
Membrane Integrity ◽  
Immunomodulatory Activity ◽  
Gram Negative Bacteria ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
Seriola Quinqueradiata ◽  
Specific Polysaccharide

Lipopolysaccharides (LPS) are surface glycoconjugates embedded in the external leaflet of the outer membrane (OM) of the Gram-negative bacteria. They consist of three regions: lipid A, core oligosaccharide (OS), and O-specific polysaccharide or O-antigen. Lipid A is the glycolipid endotoxin domain that anchors the LPS molecule to the OM, and therefore, its chemical structure is crucial in the maintenance of membrane integrity in the Gram-negative bacteria. In this paper, we reported the characterization of the lipid A and OS structures from Pseudoalteromonas nigrifaciens Sq02-Rifr, which is a psychrotrophic Gram-negative bacterium isolated from the intestine of Seriola quinqueradiata. The immunomodulatory activity of both LPS and lipid A was also examined.

scholarly journals Biosynthesis of lipopolysaccharides with different length of the O-specific region as a virulence factor of Gram-negative bacteria

2018 ◽  
Vol 72 ◽  
pp. 573-586
Author(s):  
Eva Krzyżewska ◽  
Jacek Rybka
Keyword(s):  
Outer Membrane ◽  
Lipid A ◽  
Specific Antigen ◽  
Gram Negative Bacteria ◽  
Bacterial Survival ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
O Antigen ◽  
Length Regulation ◽  
External Part

The outer membrane of Gram-negative bacteria is a biological structure with a unique composition that significantly contributes to the survival of bacteria in the unfavorable conditions of the host organism. The lipopolysaccharide constitutes about 70% of the external part of the outer membrane. The LPS molecule is composed of three different parts: lipid A, core oligosaccharide and O antigen. Despite the O-specific antigen being one of the most intensely studied surface structures of bacterial polysaccharides, a number of questions regarding the mechanism of the O antigen biosynthesis and its transport to the cell surface are still unanswered. The paper describes the biosynthesis of the lipopolysaccharide molecule, with particular emphasis on the O-specific chain biosynthesis, the mechanism of lipopolysaccharide length regulation and the influence of the type of synthesized O-specific chains on bacterial survival in adverse host organisms.

scholarly journals Gram-negative trimeric porins have specific LPS binding sites that are essential for porin biogenesis

2016 ◽  
Vol 113 (34) ◽  
pp. E5034-E5043 ◽  
Author(s):  
Wanatchaporn Arunmanee ◽  
Monisha Pathania ◽  
Alexandra S. Solovyova ◽  
Anton P. Le Brun ◽  
Helen Ridley ◽  
...  
Keyword(s):  
Binding Sites ◽  
Calcium Ion ◽  
Gram Negative Bacteria ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
X Ray ◽  
Cross Links ◽  
Phosphate Groups ◽  
Positively Charged ◽  
Lps Binding

The outer membrane (OM) of gram-negative bacteria is an unusual asymmetric bilayer with an external monolayer of lipopolysaccharide (LPS) and an inner layer of phospholipids. The LPS layer is rigid and stabilized by divalent cation cross-links between phosphate groups on the core oligosaccharide regions. This means that the OM is robust and highly impermeable to toxins and antibiotics. During their biogenesis, OM proteins (OMPs), which function as transporters and receptors, must integrate into this ordered monolayer while preserving its impermeability. Here we reveal the specific interactions between the trimeric porins of Enterobacteriaceae and LPS. Isolated porins form complexes with variable numbers of LPS molecules, which are stabilized by calcium ions. In earlier studies, two high-affinity sites were predicted to contain groups of positively charged side chains. Mutation of these residues led to the loss of LPS binding and, in one site, also prevented trimerization of the porin, explaining the previously observed effect of LPS mutants on porin folding. The high-resolution X-ray crystal structure of a trimeric porin–LPS complex not only helps to explain the mutagenesis results but also reveals more complex, subtle porin–LPS interactions and a bridging calcium ion.

scholarly journals Molecular Characterization of Lipopolysaccharide Binding to Humanα-1-Acid Glycoprotein

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Johnny X. Huang ◽  
Mohammad A. K. Azad ◽  
Elizabeth Yuriev ◽  
Mark A. Baker ◽  
Roger L. Nation ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Lipid A ◽  
Inflammatory Responses ◽  
Klebsiella Pneumonia ◽  
Gram Negative Bacteria ◽  
Surface Plasma Resonance ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
Binding Characteristics ◽  
Bacterial Lipid

The ability of AGP to bind circulating lipopolysaccharide (LPS) in plasma is believed to help reduce the proinflammatory effect of bacterial lipid A molecules. Here, for the first time we have characterized human AGP binding characteristics of the LPS from a number of pathogenic Gram-negative bacteria:Escherichia coli,Salmonella typhimurium,Klebsiella pneumonia,Pseudomonas aeruginosa, andSerratia marcescens. The binding affinity and structure activity relationships (SAR) of the AGP-LPS interactions were characterized by surface plasma resonance (SPR). In order to dissect the contribution of the lipid A, core oligosaccharide andO-antigen polysaccharide components of LPS, the AGP binding affinity of LPS from smooth strains, were compared to lipid A, Kdo2-lipid A,Ra,Rd, andRerough LPS mutants. The SAR analysis enabled by the binding data suggested that, in addition to the important role played by the lipid A and core components of LPS, it is predominately the unique species- and strain-specific carbohydrate structure of theO-antigen polysaccharide that largely determines the binding affinity for AGP. Together, these data are consistent with the role of AGP in the binding and transport of LPS in plasma during acute-phase inflammatory responses to invading Gram-negative bacteria.

scholarly journals The Chemical Composition of Endotoxin Isolated from Intestinal Strain ofDesulfovibrio desulfuricans

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Jolanta Lodowska ◽  
Daniel Wolny ◽  
Marzena Jaworska-Kik ◽  
Sławomir Kurkiewicz ◽  
Zofia Dzierżewicz ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Lipid A ◽  
Alimentary Tract ◽  
Desulfovibrio Desulfuricans ◽  
Gram Negative Bacteria ◽  
Core Oligosaccharide ◽  
Tetradecanoic Acid ◽  
Gram Negative ◽  
Specific Polysaccharide ◽  
Cellular Components

Desulfovibrio desulfuricansanaerobes are constituents of human alimentary tract microflora. There are suggestions that they take part in the pathogenesis of periodontitis and some gastrointestinal inflammatory disorders, such as ulcerative colitis or Crohn’s disease. Endotoxin is one of Gram-negative bacteria cellular components that influence these microorganisms pathogenicity. Endotoxin is a lipid-polisaccharide heteropolymer consisting of three elements: lipid A, core oligosaccharide, and O-specific polysaccharide, also called antigen-O. The biological activity of lipopolysaccharide (LPS) is determined by its structure. In this study, we show that rhamnose, fucose, mannose, glucose, galactose, heptose, and 2-keto-3-deoxyoctulosonic acid (Kdo) are constituents ofD. desulfuricansendotoxin oligosaccharide core and O-antigen. Lipid A of these bacteria LPS is composed of glucosamine disaccharide substituted by 3-acyloxyacyl residues: ester-bound 3-(dodecanoyloxy)tetradecanoic, 3-(hexadecanoyloxy)tetradecanoic acid, and amide-bound 3-(tetradecanoyloxy)tetradecanoic acid.

scholarly journals Direct detection of lipid A on intact Gram-negative bacteria by MALDI-TOF mass spectrometry

2016 ◽  
Vol 120 ◽  
pp. 68-71 ◽  
Author(s):  
Gerald Larrouy-Maumus ◽  
Abigail Clements ◽  
Alain Filloux ◽  
Ronan R. McCarthy ◽  
Serge Mostowy
Keyword(s):  
Mass Spectrometry ◽  
Lipid A ◽  
Direct Detection ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Maldi Tof Mass Spectrometry ◽  
Maldi Tof

Antimicrobial activity of Pycnarrhena cauliflora (Miers.) Diels. methanol extract

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Eti Nurwening Sholikhah ◽  
Maulina Diah ◽  
Mustofa ◽  
Masriani ◽  
Susi Iravati ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Methanolic Extract ◽  
Biological Activities ◽  
Positive Control ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Methanolic Extracts

Pycnarrhena cauliflora (Miers.) Diels., local name sengkubak, is one of indigenous plants from West Kalimantan that has been used as natural flavor. Pycnorrhena cauliflora is one of species of Menispermaceae family which is rich in bisbenzylisoquinoline alkaloids. This alkaloids are known to have various biological activities including antiprotozoal, antiplasmodial, antifungal and antibacterial activities. This study aimed to investigate antimicrobial activity of  the P. cauliflora (Miers.) Diels. methanolic extracts against gram-positive and gram-negative bacteria. The methanolic extract of P. cauliflora (Miers.) Diels., root, leaf and stem were prepared by maceration. The disk-diffusion method was then used to determine the antimicrobial activity of the extracts against Streptococcus pyogenes, S. mutants, Staphylococcus aureus, S. epidermidis, Salmonella typhi, Shigella flexneri, Pseudomonas aeruginosa and Escherichia coli after 18-24 h incubation at 37 oC. Amoxicillin was used as positive control for gram-positive bacteria and ciprofloxacin was used as gram-negative bacteria. The inhibition zones were then measured in mm. Analysis were conducted in duplicates. The results showed in general the methanolic extracts of P. cauliflora (Miers.) Diels. root (inhibition zone diameter= 10-23 mm) were more active than that leaf (0-15 mm) and stem (0-17 mm) extracts against gram-positive bacteria. The zone inhibition diameter of amoxicillin as positive control was 8-42 mm. In addition, the methanolic extracts of P. cauliflora (Miers.) Diels. root (12-17 mm) were also more active than that leaf (0-12 mm) and stem (0-12 mm) extracts against gram-negative bacteria. The zone inhibition diameter of ciprofloxacin as positive control was 33-36 mm. In conclusion, the methanolic extract of P. caulifloria (Miers.) Diels. root is the most extract active against both gram-positive and gram-negative bacteria. Further study will be focused to isolate active compounds in the methanolic extract of the root.

scholarly journals In situ identification of Gram-negative bacteria in human lungs using a topical fluorescent peptide targeting lipid A

2018 ◽  
Vol 10 (464) ◽  
pp. eaal0033 ◽  
Author(s):  
Ahsan R. Akram ◽  
Sunay V. Chankeshwara ◽  
Emma Scholefield ◽  
Tashfeen Aslam ◽  
Neil McDonald ◽  
...  
Keyword(s):  
Lipid A ◽  
Respiratory Infections ◽  
Bacterial Species ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Human Lungs ◽  
Fluorescent Peptide ◽  
Bacterial Lipid

Respiratory infections in mechanically ventilated patients caused by Gram-negative bacteria are a major cause of morbidity. Rapid and unequivocal determination of the presence, localization, and abundance of bacteria is critical for positive resolution of the infections and could be used for patient stratification and for monitoring treatment efficacy. Here, we developed an in situ approach to visualize Gram-negative bacterial species and cellular infiltrates in distal human lungs in real time. We used optical endomicroscopy to visualize a water-soluble optical imaging probe based on the antimicrobial peptide polymyxin conjugated to an environmentally sensitive fluorophore. The probe was chemically stable and nontoxic and, after in-human intrapulmonary microdosing, enabled the specific detection of Gram-negative bacteria in distal human airways and alveoli within minutes. The results suggest that pulmonary molecular imaging using a topically administered fluorescent probe targeting bacterial lipid A is safe and practical, enabling rapid in situ identification of Gram-negative bacteria in humans.

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