A novel branching pattern in the lipopolysaccharide expressed by non-typeable Haemophilus influenzae strain 1232

Vitiazeva, Varvara; Li, Jianjun; Hood, Derek W.; Moxon, E. Richard; Schweda, Elke K. H.

doi:10.1016/j.carres.2013.03.011

Cited by 3 publications

(2 citation statements)

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“…The addition of ChoP has been previously observed in a number of NTHi strains and can occur at any of the three core heptose (Hep) units (Fig. 4) (41,(44)(45)(46)(47)(48). These findings are in contrast to the most prevalent glycoforms expressed by NTHi strain 2019 (see Fig.…”

Section: -Keto-3-deoxyoctonate (Kdo) (40-44)mentioning

confidence: 91%

“…In NTHi, all three core heptoses can be further substituted with oligosaccharide chains, free phosphate (P), phosphoethanolamine (PEA), ChoP, acetate groups, and glycine (13,(41)(42)(43)(44)(45)(46)(47)(48). The addition of these various moieties can create highly heterogeneous LOS structures both between strains and within a strain.…”

Section: -Keto-3-deoxyoctonate (Kdo) (40-44)mentioning

confidence: 99%

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Comparative Analyses of the Lipooligosaccharides from Nontypeable Haemophilus influenzae and Haemophilus haemolyticus Show Differences in Sialic Acid and Phosphorylcholine Modifications

et al. 2016

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Haemophilus haemolyticus and nontypeable Haemophilus influenzae (NTHi) are closely related upper airway commensal bacteria that are difficult to distinguish phenotypically. NTHi causes upper and lower airway tract infections in individuals with compromised airways, while H. haemolyticus rarely causes such infections. The lipooligosaccharide (LOS) is an outer membrane component of both species and plays a role in NTHi pathogenesis. In this study, comparative analyses of the LOS structures and corresponding biosynthesis genes were performed. Mass spectrometric and immunochemical analyses showed that NTHi LOS contained terminal sialic acid more frequently and to a higher extent than H. haemolyticus LOS did. Genomic analyses of 10 strains demonstrated that H. haemolyticus lacked the sialyltransferase genes lic3A and lic3B (9/10) and siaA (10/10), but all strains contained the sialic acid uptake genes siaP and siaT (10/10). However, isothermal titration calorimetry analyses of SiaP from two H. haemolyticus strains showed a 3.4-to 7.3-fold lower affinity for sialic acid compared to that of NTHi SiaP. Additionally, mass spectrometric and immunochemical analyses showed that the LOS from H. haemolyticus contained phosphorylcholine (ChoP) less frequently than the LOS from NTHi strains. These differences observed in the levels of sialic acid and ChoP incorporation in the LOS structures from H. haemolyticus and NTHi may explain some of the differences in their propensities to cause disease. Nontypeable Haemophilus influenzae (NTHi) is a common commensal organism of the nasopharynx. NTHi can also cause disease in individuals with compromised upper airways (1-3). In adults, this organism is typically associated with causing pneumonia and bronchitis in individuals with chronic obstructive pulmonary disease (COPD) (4, 5), and in children, it is a causative agent of otitis media (6, 7). NTHi bacteria typically cause localized infections such as sinusitis or bronchitis, but they do have the ability to cause systemic infections such as bacteremia or meningitis (6). Haemophilus haemolyticus is also a commensal organism of the nasopharynx; it is generally considered a colonizer and is typically not associated with disease. The application of ribosomal analysis and specific gene differences has enabled resolution of these closely related organisms (8-12).Lipooligosaccharides (LOS) are the major surface glycolipids expressed by both NTHi and H. haemolyticus. LOS has been shown to be a major factor in the pathogenesis of NTHi (13-17). LOS structures that terminate in N-acetyl-5-neuraminic acid (Neu5Ac), commonly referred to as sialic acid, have been shown to be important in resistance to complement killing (13,15,17) and in the ability of the organism to cause otitis media in the chinchilla model of infection (15,16). Additionally, Weiser et al. have shown that phosphorylcholine (ChoP) can be expressed on NTHi LOS in a phase variable manner (18). The interaction between the platelet-activating factor (PAF) receptor and ChoP has been sh...

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