Deficiency of peptidoglycan and lipopolysaccharide components in Rickettsia tsutsugamushi

Amano, Ken‐ichi; Tamura, Akira; Ohashi, Norio; Urakami, Hiroshi; Kaya, Shunji; Fukushi, Kazue

doi:10.1128/iai.55.9.2290-2292.1987

Cited by 85 publications

(43 citation statements)

References 27 publications

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“…These results suggest that O. tsutsugamushi-mediated production of TNF-α requires certain signals which are not mainly mediated by TLR4 and LPS. These results are consistent with the report that, unlike other closely related rickettsial organisms such as Rickettsia rickettsii and Rickettsia prowazekii, O. tsutsugamushi has little or no LPS component in the bacterial cell walls (23). LPS is known to be the microbial component which induces macrophages to produce inflammatory cytokines.…”

supporting

confidence: 92%

Mitogen‐activated protein kinases are involved in tumor necrosis factor alpha production in macrophages infected with Orientia tsutsugamushi

Yun¹,

Koo²,

Koh³

2009

Microbiology and Immunology

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Orientia tsutsugamushi, an obligatory intracellular bacterium, is the causative agent of scrub typhus. Here the role of MAPK in TNF-α production in macrophages after infection with O. tsutsugamushi has been investigated. ERK1/2, JNK, and p38 MAPK became phosphorylated in Orientia-stimulated macrophages. Selective inhibitors of MAPK cascades could all significantly reduce Orientia-stimulated TNF-α production. Orientia-stimulated TNF-α production via p38 and JNK pathways was regulated by a post-transcriptional mechanism, whereas the ERK pathway mainly controlled the transcriptional step of TNF-α gene expression during infection. In conclusion, our data indicate that MAPK signaling is required to induce maximal TNF-α production in macrophages during Orientia infection.

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supporting

confidence: 92%

Mitogen‐activated protein kinases are involved in tumor necrosis factor alpha production in macrophages infected with Orientia tsutsugamushi

Yun¹,

Koo²,

Koh³

2009

Microbiology and Immunology

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“…PK treatment of Proteus OXK showed many ladder bands similar to those seen previously in Proteus OXK-LPS (13). In the case of R. tsutsugamushi, LPS-like bands were not observed after PK treatment, confirming that this rickettsia lacks LPS (2).…”

Section: Detection Of Antigenic Components By Immunoblottingsupporting

confidence: 79%

“…Furthermore, we showed in this study that Proteus OXK-LPS was reacted with these sera as the common antigens with R. tsutsugamushi. However, because this rickettsia does not contain LPS (2), the components sharing the common antigens with Proteus OXK-LPS may be complexes including sugars like glycoproteins, other than LPS. However, reports concerning the common antigenicity between LPS and glycoproteins have never been published.…”

Section: Discussionmentioning

confidence: 99%

Serological Reactivity of Sera from Scrub Typhus Patients against Weil‐Felix Test Antigens

Amano

Suzuki

Fujita

et al. 1993

Microbiology and Immunology

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Sera from 17 patients of scrub typhus in the acute and convalescent phases were tested by indirect immunoperoxidase test, Weil-Felix (WF) test, enzyme-linked immunosorbent assay (ELISA), and immunoblotting. In the comparison of antibody titers between acute-and convalescent-phase sera, we recognized a parallelism of increment between the titers in WF test and titers of immunoglobulin M (IgM) in ELISA against Proteus mirabilis strain OXK-whole cells and OXKlipopolysaccharides (Proteus OXK-LPS). Furthermore, IgM antibodies from almost all of WF testpositive sera recognized LPS from Proteus OXK in immunoblotting. Based on these results, it was concluded that IgM antibody rather than IgG may participate in WF test, and that Proteus OXK-LPS may have one of antigenic epitopes common to the components of R. tsutsugamushi.

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“…Orientia has previously been reported to completely lack both peptidoglycan and LPS (Amano et al, 1987). This conclusion was based on an insensitivity to penicillin (Wisseman et al, 1982), an inability to detect peptidoglycan fragments by chemical analysis (Amano et al, 1987), and an absence of electron-dense material in the periplasmic inter-membrane space by electron microscopy (Silverman and Wisseman, 1978).…”

Section: Introductionmentioning

confidence: 99%

Evidence for a peptidoglycan‐like structure in Orientia tsutsugamushi

Atwal

Giengkam

Chaemchuen

et al. 2017

Molecular Microbiology

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Summary Bacterial cell walls are composed of the large cross-linked macromolecule peptidoglycan, which maintains cell shape and is responsible for resisting osmotic stresses. This is a highly conserved structure and the target of numerous antibiotics. Obligate intracellular bacteria are an unusual group of organisms that have evolved to replicate exclusively within the cytoplasm or vacuole of a eukaryotic cell. They tend to have reduced amounts of peptidoglycan, likely due to the fact that their growth and division takes place within an osmotically protected environment, and also due to a drive to reduce activation of the host immune response. Of the two major groups of obligate intracellular bacteria, the cell wall has been much more extensively studied in the Chlamydiales than the Rickettsiales. Here, we present the first detailed analysis of the cell envelope of an important but neglected member of the Rickettsiales, Orientia tsutsugamushi. This bacterium was previously reported to completely lack peptidoglycan, but here we present evidence supporting the existence of a peptidoglycan-like structure in Orientia, as well as an outer membrane containing a network of cross-linked proteins, which together confer cell envelope stability. We find striking similarities to the unrelated Chlamydiales, suggesting convergent adaptation to an obligate intracellular lifestyle.

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Deficiency of peptidoglycan and lipopolysaccharide components in Rickettsia tsutsugamushi

Cited by 85 publications

References 27 publications

Mitogen‐activated protein kinases are involved in tumor necrosis factor alpha production in macrophages infected with Orientia tsutsugamushi

Mitogen‐activated protein kinases are involved in tumor necrosis factor alpha production in macrophages infected with Orientia tsutsugamushi

Serological Reactivity of Sera from Scrub Typhus Patients against Weil‐Felix Test Antigens

Evidence for a peptidoglycan‐like structure in Orientia tsutsugamushi

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