scholarly journals Analysis of the Structure and Biosynthesis of the Lipopolysaccharide Core Oligosaccharide of Pseudomonas syringae pv. tomato DC3000

2021 ◽  
Vol 22 (6) ◽  
pp. 3250
Author(s):  
Alexander Kutschera ◽  
Ursula Schombel ◽  
Dominik Schwudke ◽  
Stefanie Ranf ◽  
Nicolas Gisch
Keyword(s):  
Pseudomonas Syringae ◽  
Species Complex ◽  
Inner Core ◽  
Divalent Cations ◽  
Membrane Integrity ◽  
Outer Core ◽  
Core Oligosaccharide ◽  
Structure Information ◽  
The Core ◽  
Genetic Components

Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, is important for bacterial viability in general and host–pathogen interactions in particular. Negative charges at its core oligosaccharide (core-OS) contribute to membrane integrity through bridging interactions with divalent cations. The molecular structure and synthesis of the core-OS have been resolved in various bacteria including the mammalian pathogen Pseudomonas aeruginosa. A few core-OS structures of plant-associated Pseudomonas strains have been solved to date, but the genetic components of the underlying biosynthesis remained unclear. We conducted a comparative genome analysis of the core-OS gene cluster in Pseudomonas syringae pv. tomato (Pst) DC3000, a widely used model pathogen in plant–microbe interactions, within the P. syringae species complex and to other plant-associated Pseudomonas strains. Our results suggest a genetic and structural conservation of the inner core-OS but variation in outer core-OS composition within the P. syringae species complex. Structural analysis of the core-OS of Pst DC3000 shows an uncommonly high phosphorylation and presence of an O-acetylated sugar. Finally, we combined the results of our genomic survey with available structure information to estimate the core-OS composition of other Pseudomonas species.

scholarly journals Structural Analysis of the Core Region of O-Lipopolysaccharide of Porphyromonas gingivalis from Mutants Defective in O-Antigen Ligase and O-Antigen Polymerase

2009 ◽  
Vol 191 (16) ◽  
pp. 5272-5282 ◽  
Author(s):  
Nikolay A. Paramonov ◽  
Joseph Aduse-Opoku ◽  
Ahmed Hashim ◽  
Minnie Rangarajan ◽  
Michael A. Curtis
Keyword(s):  
Porphyromonas Gingivalis ◽  
Inner Core ◽  
Outer Region ◽  
Outer Core ◽  
Core Region ◽  
Resonance Spectroscopy ◽  
Core Oligosaccharide ◽  
Unusual Structure ◽  
The Core ◽  
O Antigen

ABSTRACT Porphyromonas gingivalis synthesizes two lipopolysaccharides (LPSs), O-LPS and A-LPS. Here, we elucidate the structure of the core oligosaccharide (OS) of O-LPS from two mutants of P. gingivalis W50, ΔPG1051 (WaaL, O-antigen ligase) and ΔPG1142 (O-antigen polymerase), which synthesize R-type LPS (core devoid of O antigen) and SR-type LPS (core plus one repeating unit of O antigen), respectively. Structural analyses were performed using one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy in combination with composition and methylation analysis. The outer core OS of O-LPS occurs in two glycoforms: an “uncapped core,” which is devoid of O polysaccharide (O-PS), and a “capped core,” which contains the site of O-PS attachment. The inner core region lacks l(d)-glycero-d(l)-manno-heptosyl residues and is linked to the outer core via 3-deoxy-d-manno-octulosonic acid, which is attached to a glycerol residue in the outer core via a monophosphodiester bridge. The outer region of the “uncapped core” is attached to the glycerol and is composed of a linear α-(1→3)-linked d-Man OS containing four or five mannopyranosyl residues, one-half of which are modified by phosphoethanolamine at position 6. An amino sugar, α-d-allosamine, is attached to the glycerol at position 3. In the “capped core,” there is a three- to five-residue extension of α-(1→3)-linked Man residues glycosylating the outer core at the nonreducing terminal residue. β-d-GalNAc from the O-PS repeating unit is attached to the nonreducing terminal Man at position 3. The core OS of P. gingivalis O-LPS is therefore a highly unusual structure, and it is the basis for further investigation of the mechanism of assembly of the outer membrane of this important periodontal bacterium.

Multiple inner core reflections from a Novaya Zemlya explosion

1972 ◽  
Vol 62 (4) ◽  
pp. 1063-1071 ◽  
Author(s):  
R. D. Adams
Keyword(s):  
Lower Bound ◽  
Inner Core ◽  
Nuclear Explosion ◽  
Outer Core ◽  
Low Velocity ◽  
Mantle Boundary ◽  
Core Mantle Boundary ◽  
Novaya Zemlya ◽  
The Core ◽  
Velocity Channel

Abstract The phases P2KP, P3KP, and P4KP are well recorded from the Novaya Zemlya nuclear explosion of October 14, 1970, with the branch AB at distances of up to 20° beyond the theoretical end point A. This extension is attributed to diffraction around the core-mantle boundary. A slowness dT/dΔ = 4.56±0.02 sec/deg is determined for the AB branch of P4KP, in excellent agreement with recent determinations of the slowness of diffracted P. This slowness implies a velocity of 13.29±0.06 km/sec at the base of the mantle, and confirms recent suggestions of a low-velocity channel above the core-mantle boundary. There is evidence that arrivals recorded before the AB branch of P2KP may lie on two branches, with different slownesses. The ratio of amplitudes of successive orders of multiple inner core reflections gives a lower bound of about 2200 for Q in the outer core.

scholarly journals Structure of the core oligosaccharide of a rough-type lipopolysaccharide of Pseudomonas syringae pv. phaseolicola

2004 ◽  
Vol 271 (23-24) ◽  
pp. 4968-4977 ◽  
Author(s):  
Evelina L. Zdorovenko ◽  
Evgeny Vinogradov ◽  
Galina M. Zdorovenko ◽  
Buko Lindner ◽  
Olga V. Bystrova ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Core Oligosaccharide ◽  
The Core

scholarly journals Pasteurella multocida Expresses Two Lipopolysaccharide Glycoforms Simultaneously, but Only a Single Form Is Required for Virulence: Identification of Two Acceptor-Specific Heptosyl I Transferases

2007 ◽  
Vol 75 (8) ◽  
pp. 3885-3893 ◽  
Author(s):  
Marina Harper ◽  
John D. Boyce ◽  
Andrew D. Cox ◽  
Frank St. Michael ◽  
Ian W. Wilkie ◽  
...  
Keyword(s):  
Pasteurella Multocida ◽  
Inner Core ◽  
Phase Variation ◽  
Outer Core ◽  
Core Oligosaccharide ◽  
Bacterial Mutants ◽  
Major Antigen ◽  
First Time ◽  
Mucosal Pathogens

ABSTRACT Lipopolysaccharide (LPS) is a critical virulence determinant in Pasteurella multocida and a major antigen responsible for host protective immunity. In other mucosal pathogens, variation in LPS or lipooligosaccharide structure typically occurs in the outer core oligosaccharide regions due to phase variation. P. multocida elaborates a conserved oligosaccharide extension attached to two different, simultaneously expressed inner core structures, one containing a single phosphorylated 3-deoxy-d-manno-octulosonic acid (Kdo) residue and the other containing two Kdo residues. We demonstrate that two heptosyltransferases, HptA and HptB, add the first heptose molecule to the Kdo1 residue and that each exclusively recognizes different acceptor molecules. HptA is specific for the glycoform containing a single, phosphorylated Kdo residue (glycoform A), while HptB is specific for the glycoform containing two Kdo residues (glycoform B). In addition, KdkA was identified as a Kdo kinase, required for phosphorylation of the first Kdo molecule. Importantly, virulence data obtained from infected chickens showed that while wild-type P. multocida expresses both LPS glycoforms in vivo, bacterial mutants that produced only glycoform B were fully virulent, demonstrating for the first time that expression of a single LPS form is sufficient for P. multocida survival in vivo. We conclude that the ability of P. multocida to elaborate alternative inner core LPS structures is due to the simultaneous expression of two different heptosyltransferases that add the first heptose residue to the nascent LPS molecule and to the expression of both a bifunctional Kdo transferase and a Kdo kinase, which results in the initial assembly of two inner core structures.

Analytical Evaluation of Core Bowing Reactivity in the 4S Reactor

2009 ◽  
Author(s):  
Satoshi Nishimura ◽  
Hirokazu Ohta ◽  
Nobuyuki Ueda
Keyword(s):  
Fast Reactor ◽  
Radial Displacement ◽  
Inner Core ◽  
Structural Characteristics ◽  
Outer Core ◽  
Radial Expansion ◽  
Neutron Absorption ◽  
Analytical Evaluation ◽  
Life Condition ◽  
The Core

The 4S (super-safe, small and simple) reactor is a sodium-cooled small fast reactor. The core reactivity is controlled by moving the reflectors installed around the core, and the reactor has a fixed absorber at the core center to accomplish a long core lifetime. To evaluate core bowing behavior and the resulting reactivity feedback in the 4S reactor, an analytical evaluation was conducted under various core power to flow ratios (P/F). The core bowing reactivity under the BOC (beginning of core life) condition becomes increasingly negative with increasing P/F up to 2.0, then becomes less negative with increasing P/F from 2.0 to 3.0, and finally becomes positive at P/F = 3.0. The bowing reactivity under the EOC (end of core life) condition becomes increasingly negative with increasing P/F up to 1.5, then becomes less negative then positive with increasing P/F from 1.5 to 3.0; the core bowing reactivity is positive when P/F ≥ 2.0. These results are mainly caused by the following two mechanisms originating from the structural characteristics of the 4S reactor: - a decrease in neutron absorption by the fixed absorber due to the radial displacement of the inner core subassemblies (under the BOC condition); - a decrease in neutron streaming caused by the small gaps between the outer core subassemblies and the reflectors due to core radial expansion (under the EOC condition).

scholarly journals Functional Characterization of MigA and WapR: Putative Rhamnosyltransferases Involved in Outer Core Oligosaccharide Biosynthesis of Pseudomonas aeruginosa

2008 ◽  
Vol 190 (6) ◽  
pp. 1857-1865 ◽  
Author(s):  
Karen K. H. Poon ◽  
Erin L. Westman ◽  
Evgeny Vinogradov ◽  
Shouguang Jin ◽  
Joseph S. Lam
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Functional Characterization ◽  
Outer Core ◽  
Resonance Spectroscopy ◽  
Core Oligosaccharide ◽  
Strain Pao1 ◽  
The Core ◽  
O Antigen ◽  
Knockout Mutants

ABSTRACT Pseudomonas aeruginosa lipopolysaccharide (LPS) contains two glycoforms of core oligosaccharide (OS); one form is capped with O antigen through an α-1,3-linked l-rhamnose (l-Rha), while the other is uncapped and contains an α-1,6-linked l-Rha. Two genes in strain PAO1, wapR (PA5000) and migA (PA0705), encode putative glycosyltransferases associated with core biosynthesis. We propose that WapR and MigA are the rhamnosyltransferases responsible for the two linkages of l-Rha to the core. Knockout mutants with mutations in both genes were generated. The wapR mutant produced LPS lacking O antigen, and addition of wapR in trans complemented this defect. The migA mutant produced LPS with a truncated outer core and showed no reactivity to outer core-specific monoclonal antibody (MAb) 5C101. Complementation of this mutant with migA restored reactivity of the LPS to MAb 5C101. Interestingly, LPS from the complemented migA strain was not reactive to MAb 18-19 (specific for the core-plus-one O repeat). This was due to overexpression of MigA in the complemented strain that caused an increase in the proportion of the uncapped core OS, thereby decreasing the amount of the core-plus-one O repeat, indicating that MigA has a regulatory role. The structures of LPS from both mutants were elucidated using nuclear magnetic resonance spectroscopy and mass spectrometry. The capped core of the wapR mutant was found to be truncated and lacked α-1,3-l-Rha. In contrast, uncapped core OS from the migA mutant lacked α-1,6-l-Rha. These results provide evidence that WapR is the α-1,3-rhamnosyltransferase, while MigA is the α-1,6-rhamnosyltransferase.

scholarly journals Relative Contributions of Lipooligosaccharide Inner and Outer Core Modifications to Nontypeable Haemophilus influenzae Pathogenesis

2013 ◽  
Vol 81 (11) ◽  
pp. 4100-4111 ◽  
Author(s):  
Pau Morey ◽  
Cristina Viadas ◽  
Begoña Euba ◽  
Derek W. Hood ◽  
Montserrat Barberán ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Bacterial Resistance ◽  
Inner Core ◽  
Outer Core ◽  
Nontypeable Haemophilus Influenzae ◽  
Core Oligosaccharide ◽  
Biofilm Growth ◽  
Content Type ◽  
Relative Contribution ◽  
Self Aggregation

ABSTRACTNontypeableHaemophilus influenzae(NTHi) is a frequent commensal of the human nasopharynx that causes opportunistic infection in immunocompromised individuals. Existing evidence associates lipooligosaccharide (LOS) with disease, but the specific and relative contributions of NTHi LOS modifications to virulence properties of the bacterium have not been comprehensively addressed. Using NTHi strain 375, an isolate for which the detailed LOS structure has been determined, we compared systematically a set of isogenic mutant strains expressing sequentially truncated LOS. The relative contributions of 2-keto-3-deoxyoctulosonic acid, the triheptose inner core, oligosaccharide extensions on heptoses I and III, phosphorylcholine, digalactose, and sialic acid to NTHi resistance to antimicrobial peptides (AMP), self-aggregation, biofilm formation, cultured human respiratory epithelial infection, and murine pulmonary infection were assessed. We show thatopsX,lgtF,lpsA,lic1, andlic2Acontribute to bacterial resistance to AMP;lic1is related to NTHi self-aggregation;lgtF,lic1, andsiaBare involved in biofilm growth;opsXandlgtFparticipate in epithelial infection; andopsX,lgtF, andlpsAcontribute to lung infection. Depending on the phenotype, the involvement of these LOS modifications occurs at different extents, independently or having an additive effect in combination. We discuss the relative contribution of LOS epitopes to NTHi virulence and frame a range of pathogenic traits in the context of infection.

scholarly journals The lipopolysaccharide of the mastitis isolate Escherichia coli strain 1303 comprises a novel O-antigen and the rare K-12 core type

Microbiology ◽  
2011 ◽  
Vol 157 (6) ◽  
pp. 1750-1760 ◽  
Author(s):  
Katarzyna A. Duda ◽  
Buko Lindner ◽  
Helmut Brade ◽  
Andreas Leimbach ◽  
Elżbieta Brzuszkiewicz ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Inner Core ◽  
Bovine Mastitis ◽  
Outer Core ◽  
Coli Strain ◽  
Core Oligosaccharide ◽  
2D Nmr Spectroscopy ◽  
E Coli ◽  
O Antigen ◽  
K 12

Mastitis represents one of the most significant health problems of dairy herds. The two major causative agents of this disease are Escherichia coli and Staphylococcus aureus. Of the first, its lipopolysaccharide (LPS) is thought to play a prominent role during infection. Here, we report the O-antigen (OPS, O-specific polysaccharide) structure of the LPS from bovine mastitis isolate E. coli 1303. The structure was determined utilizing chemical analyses, mass spectrometry, and 1D and 2D NMR spectroscopy methods. The O-repeating unit was characterized as -[→4)-β-d-Quip3NAc-(1→3)-α-l-Fucp2OAc-(1→4)-β-d-Galp-(1→3)-α-d-GalpNAc-(1→]- in which the O-acetyl substitution was non-stoichiometric. The nucleotide sequence of the O-antigen gene cluster of E. coli 1303 was also determined. This cluster, located between the gnd and galF genes, contains 13 putative open reading frames, most of which represent unknown nucleotide sequences that have not been described before. The O-antigen of E. coli 1303 was shown to substitute O-7 of the terminal ld-heptose of the K-12 core oligosaccharide. Interestingly, the non-OPS-substituted core oligosaccharide represented a truncated version of the K-12 outer core – namely terminal ld-heptose and glucose were missing; however, it possessed a third Kdo residue in the inner core. On the basis of structural and genetic data we show that the mastitis isolate E. coli 1303 represents a new serotype and possesses the K-12 core type, which is rather uncommon among human and bovine isolates.

Viscous drag and the differential rotation of the Earth's core

1997 ◽  
Vol 57 (1) ◽  
pp. 231-233
Author(s):  
DAVID L. BOOK ◽  
J. A. VALDIVIA
Keyword(s):  
Simple Model ◽  
Differential Rotation ◽  
Dynamic Viscosity ◽  
Inner Core ◽  
Outer Core ◽  
Viscous Drag ◽  
Earth’S Rotation ◽  
The Core ◽  
The Earth ◽  
Earth’S Inner Core

It is proposed that the differential rotation of the Earth's inner core deduced by Song and Richards is due to a combination of the deceleration of the Earth's rotation and the viscous drag between the Earth's inner and outer cores. If this model is correct then the dynamic viscosity in the outer core of the Earth can be estimated to be μ≈104 poise. Besides providing a novel way of determining the viscosity of the core, this simple model suggests some new tests and shows how astronomical effects can influence geological phenomena.

scholarly journals Identification of the Linkage between A-Polysaccharide and the Core in the A-Lipopolysaccharide of Porphyromonas gingivalis W50

2015 ◽  
Vol 197 (10) ◽  
pp. 1735-1746 ◽  
Author(s):  
Nikolay Paramonov ◽  
Joseph Aduse-Opoku ◽  
Ahmed Hashim ◽  
Minnie Rangarajan ◽  
Michael A. Curtis
Keyword(s):  
Porphyromonas Gingivalis ◽  
Biosynthetic Pathway ◽  
Attachment Site ◽  
Outer Core ◽  
Etiologic Agent ◽  
Core Oligosaccharide ◽  
Content Type ◽  
The Core ◽  
O Antigen ◽  
Mutant Strains

ABSTRACTPorphyromonas gingivalissynthesizes two lipopolysaccharides (LPSs), O-LPS and A-LPS. The structure of the core oligosaccharide (OS) of O-LPS and the attachment site of the O-polysaccharide (O-PS) repeating unit [→3)-α-d-Galp-(1→6)-α-d-Glcp-(1→4)-α-l-Rhap-(1→3)-β-d-GalNAcp-(1→] to the core have been elucidated using the ΔPG1051 (WaaL, O-antigen ligase) and ΔPG1142 (Wzy, O-antigen polymerase) mutant strains, respectively. The core OS occurs as an “uncapped” glycoform devoid of O-PS and a “capped” glycoform that contains the attachment site of O-PS via β-d-GalNAc at position O-3 of the terminal α-(1→3)-linked mannose (Man) residue. In this study, the attachment site of A-PS to the core OS was determined based on structural analysis of SR-type LPS (O-LPS and A-LPS) isolated from aP. gingivalisΔPG1142 mutant strain by extraction with aqueous hot phenol to minimize the destruction of A-LPS. Application of one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy in combination with methylation analysis showed that the A-PS repeating unit is linked to a nonterminal α-(1→3)-linked Man of the “capped core” glycoform of outer core OS at position O-4 via a →6)-[α-d-Man-α-(1→2)-α-d-Man-1-phosphate→2]-α-d-Man-(1→ motif. In order to verify that O-PS and A-PS are attached to almost identical core glycoforms, we identified a putative α-mannosyltransferase (PG0129) inP. gingivalisW50 that may be involved in the formation of core OS. Inactivation of PG0129 led to the synthesis of deep-R-type LPS with a truncated core that lacks α-(1→3)-linked mannoses and is devoid of either O-PS or A-PS. This indicated that PG0129 is an α-1,3-mannosyltransferase required for synthesis of the outer core regions of both O-LPS and A-LPS inP. gingivalis.IMPORTANCEPorphyromonas gingivalis, a Gram-negative anaerobe, is considered to be an important etiologic agent in periodontal disease, and among the virulence factors produced by the organism are two lipopolysaccharides (LPSs), O-LPS and A-LPS. The structures of the O-PS and A-PS repeating units, the core oligosaccharide (OS), and the linkage of the O-PS repeating unit to the core OS in O-LPS have been elucidated by our group. It is important to establish whether the attachment site of the A-PS repeating unit to the core OS in A-LPS is similar to or differs from that of the O-PS repeating unit in O-LPS. As part of understanding the biosynthetic pathway of the two LPSs inP. gingivalis, PG0129 was identified as an α-mannosyltransferase that is involved in the synthesis of the outer core regions of both O-LPS and A-LPS.

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