• Title, Summary, Keyword: Orientia

Search Result 34, Processing Time 0.031 seconds

Oxidant Activities in Human Dermal Microvascular Endothelial Cells Infected with Orientia tsutsugamushi (Orientia tsutsugamushi에 감염된 인간 피부 미세혈관 내피세포의 산화 활성)

  • Koh Young-Sang
    • Korean Journal of Microbiology
    • /
    • v.41 no.3
    • /
    • pp.232-235
    • /
    • 2005
  • Transcripts levels of superoxide dismutases increase slightly following infection of human dermal microvascular endothelial cells(HMEC-1) by the obligae intracellular bacterium Orientia tsutsugamushi, the causative agent of scrub typhus. In addition, fluorescence-activated cell sorter analysis demonstrates significant intracellular peroxide activity in infected cells within 5 hr after exposure to O. tsutsugamushi. Furthermore, infected cells experienced a significant depletion of glutathiones. These results support hypothesis that cells infected by this intracellular bacterium experience oxidant-mediated injury.

Seropositive Rate of Orientia Tsutsugamushi in Tamias Sibiricus from Korea (한국산 다람쥐의 Orientia Tsutsugamushi에 대한 항체양성율)

  • Song, Jin-Won;Lee, Sang-Won;Kho, Eun-Young;Chung, Ki-Mo;Lee, Yong-Ju;Song, Ki-Joon;Baek, Luck-Ju
    • The Journal of the Korean Society for Microbiology
    • /
    • v.35 no.1
    • /
    • pp.61-68
    • /
    • 2000
  • Among wild chipmunks, Tamias sibiricus, captured in Kyunggi and Kangwon province in Korea, 1997, seropositivity for Orientia tsutsugamushi was determined. Serological test for Orientia tsutsugamushi infection was performed using indirect immunofluorescent antibody technique (IFA). Of 243 wild chipmunks, 61 against Gilliam strain and 64 against Karp strain of Orientia tsutsugamushi were IFA positive. Seropositivity against Gilliam strain was shown 33.3% in Kyunggi and 23.5% in Kangwon province, and against Karp strain was shown 33.3% and 25.4%, respectively.

  • PDF

Infectivity of Orientia tsutsugamushi to Various Eukaryotic Cells and Their Cellular Invasion Mechanism (Orientia tsutsugamushi의 유핵세포내 감염능 분석 및 기전)

  • Ihn, Kyung-Soo;Han, Seung-Hoon;Kim, Hang-Rae;Seong, Seung-Yong;Kim, Ik-Sang;Choi, Myung-Sik
    • The Journal of the Korean Society for Microbiology
    • /
    • v.34 no.5
    • /
    • pp.435-443
    • /
    • 1999
  • Orientia tsutsugamushi is obligate intracellular bacterium that grows within the cytoplasm of the eukaryotic host cells. Therefore capability of the attachment, entry into the host cell and intracellular survival should be critical process for oriential infection. In this study we investigated the cellular invasion mechanism of Orientia tsutsugamushi and the role of transmembrane heparan sulfate proteoglycan, which binds diverse components at the cellular microenvironment and is implicated as host cell receptors for a variety of microbial pathogens. First of all Orientia tsutsugamushi can invade a wide range of nonprofessional phagocytic cells including fibroblast, epithelial cells and endothelial cells of various host species, including Band T lymphocytes. Thus, it was postulated that the attachment of O. tsutsugamushi requires the recognition of ubiquitous surface structures of many kinds of host cells. Treatments with heparan sulfate and heparin inhibited the infection of Orientia tsutsugamushi in dose-dependent manner for L cell, mouse fibroblast, whereas other glycosaminoglycans such as chondroitin sulfate had no effect. Collectively, these findings provide strong evidence that initial interaction with heparan sulfate proteoglycan is required for the oriential invasion into host cells.

  • PDF

Alterations in the Activities of Antioxidant Enzymes of Human Dermal Microvascular Endothelial Cells Infected with Orientia tsutsugamushi

  • Koh, Young-Sang
    • Journal of Microbiology
    • /
    • v.39 no.2
    • /
    • pp.142-145
    • /
    • 2001
  • Changes in the Activities of several antioxidant enzymes in transformed human dermal microvascular endothelial Cells (HMEC-1) by infection with the obligate intracellular bacterium Orientia tsutsugamushi, the causative agent of scrub typhus, were investigated. The activities of glucose-6-phosphate dehydrogenase, catalase, and glutathione peroxidase were significantly decreased in HMEC-1 cells infected with Ο. tsutsugamushi. However, the level of superoxide dismutase increased slightly. Furthermore, Increased levels of intracellular peroxide was observed in HMEC-1 during infection. These results support the hypothesis that cells infected by this intracellular bacterium experience oxidant-mediated injury that may eventually contribute to cell death.

  • PDF

Chemokine Gene Expression in Mice during Orientia tsutsugamushi Infection

  • Koh, Young-Sang
    • Journal of Microbiology
    • /
    • v.41 no.3
    • /
    • pp.266-270
    • /
    • 2003
  • Orientia tsutsugamushi, an obligate intracellular bacterium, is the causative agent of scrub typhus which is histopathologically characterized by inflammatory manifestations. To understand the pathogenesis of scrub typhus, chemokine gene expression in mice after infection with O. tsutsugamushi was investigated. The mRNAs that were upregulated included macrophage inflammatory proteins 1${\alpha}$/${\beta}$ (MIP-1${\alpha}$/${\beta}$), MIP-2, monocyte chemoattractant protein 1, RANTES (regulated upon activation, normal T-cell expressed and secreted), and gamma-interferon-inducible protein 10. Peak expression of these chemokines was observed six days after infection. These responses returned to or approached baseline preinfection levels by eight days after infection. Chemokine profiles in infected mice were well correlated with the kinetics of inflammatory cell infiltration. Thus, O. tsutsugamushi appears to be a strong inducer of chemokines which may significantly contribute to the inflammation observed in scrub typhus by attracting and activating phagocytic leukocytes.

Molecular Cloning of the Superoxide Dismutase Gene from Orientia tsutsugamushi, the Causative Agent of Scrub Typhus

  • Koh, Young-Sang;Yun, Ji-Hyun;Kim, Se-Jae
    • Journal of Microbiology
    • /
    • v.40 no.2
    • /
    • pp.151-155
    • /
    • 2002
  • A Superoxide Dismutase (SOD) gene from the obligate intracellular bacterium Orientia tsutsugamushi has been cloned by using the polymerase chain reaction with degenerate oligonucleotide primers corresponding to conserved regions of known SODs. Nucleotide sequencing revealed that the predicted amino acid sequence was significantly more homologous to known iron-containing SODs (FeSOD) than to manganese-containing SODs (MnSOD). Conserved regions in bacterial FeSOD could also be seen. Isolation of the oriential SOD gene may provide an opportunity to examine its role in the intracellular survival of this bacterium.

Expression of Chemokine and Tumor Necrosis Factor Alpha Genes in Murine Peritoneal Macrophages Infected with Orientia tsutsugamushi

  • Koh, Young-Sang
    • Journal of Microbiology
    • /
    • v.39 no.3
    • /
    • pp.186-194
    • /
    • 2001
  • Scrub typhus, caused by Orientia tsutsugamushi infection, is clinically and histopathologically characterized by local as well as systemic inflammatory reactions, indicating that orientiae induce mechanisms that amplify the inflammatory response. To reveal underlying mechanisms of chemoattraction and activation of responding leukocytes, expression of chemokine and tumor necrosis factor alpha (TNF-$\alpha$) genes in murine peritoneal macrophages after infection with the obligate intracellular bacterium Ο.tsutsugamushi was investigated. The genes that were unregulated included macrophage inflammatory proteins l$\alpha$/$\beta$(MIP-l$\alpha$/$\beta$), MIP-2, monocyte chemoattractant protein 1(MCP-1), RANTES (regulated upon activation, normal T-cell expressed and secreted), gamma-interferon-inducible protein 10(IP-10) and TNF-$\alpha$. Peak expression of these chemokines and TNF-$\alpha$ was observed between 1 and 3 h after infection. These responses returned to or approached baseline preinfection levels 6 h after challenge. Semiquantitative reverse transcription (RT)-PCR analysis revealed dramatic Increases during infection in the steady-state levels of mRNA ceding for the inhibitory subunit of NF-kB (IkB$\alpha$), whose transcription is enhanced by binding of NF-kB within the IkB$\alpha$promoter region. Thus, Ο. tsutsugamushi appears to be a stung inducer of chemokines and TNF-$\alpha$ which may significantly contribute to inflammation and tissue damage observed in scrub typhus by attracting and activating phagocytic leukocytes.

  • PDF

Longevity of Antibodies to Live Orientia tsutsugamushi Inoculated in Sprague Dawley Rats

  • An, Chang-Nam;Kim, Sung-Min;Kim, Tae-Yeon;Bae, Luck-Ju;Kim, Chul-Joong;Shin, Kwang-Soon;Park, Song-Yong
    • The Journal of Korean Society of Virology
    • /
    • v.28 no.2
    • /
    • pp.193-201
    • /
    • 1998
  • In Sprague Dawley (SD) rats, antibodies against strains of Orientia tsutsugamushi, Kato, Karp and Gilliam, were produced in order to investigate their longevity and cross-reactivities to their corresponding homologous and heterologous antigens. By immunofluorescence assay (IFA) of IgG and IgM, it was shown that the immunity to the homologous strains persisted at a higher level (longevity of at least 34 weeks with higher IFA titers). On the other hand, the immunity to the heterologous strains persisted at a lower level (longevity of 10 to 34 weeks with lower IFA titers). Since infection with one strain of O. tsutsugamushi does not preclude reinfection with other strains, understanding of the antigenic diversity of O. tsutsugamushi and duration of the immunity to both homologous and heterologous strain is very important in diagnosis of scrub typhus.

  • PDF

Survey of Rickettsia spp. and Orientia tsutsugamushi Pathogens Found in Animal Vectors (Ticks, Fleas, Chiggers) in Bangkaew District, Phatthalung Province, Thailand

  • Sanprick, Amornrat;Yooyen, Thanapon;Rodkvamtook, Wuttikon
    • The Korean Journal of Parasitology
    • /
    • v.57 no.2
    • /
    • pp.167-173
    • /
    • 2019
  • Rickettsial infections (Rickettsioses) are the causes of acute fever found in Thailand. It is classified as acute febrile illnesses transmitted by bloodsucking arthropod vectors (tick, flea, and chigger). This research investigated pathogens of scrub typhus in vectors from Bangkaew District, Phatthalung Province. A total of 303 pools of vector samples were ticks (Rhipicephalus sanguineus, R. microplus, and Haemaphysalis sp.), fleas (Ctenocephalides felis orientis, C. f. felis, and C. canis), and chiggers (Leptotrombidium deliense, Aschoschoengastia indica, Blankaartia acuscutellaris and Walchia disparunguis pingue) collected from reservoir hosts (dogs and rodents). The 17 and 56 kDa gene of Rickettsia causing scrub typhus were found in 29% of ticks and 98% of flea. DNA sequence analysis reveeled the detected strains were R. asembonensis and Rickettsia sp. cf1 and 5.The chiggers, 1%, were infected with Rickettsia strain TA763, a pathogen of scrub typhus.

Increased Expression of Adhesion Molecules on Human Umbilical Vein Endothelial Cells by Orientia tsutsugamushi Infection (Orientia tsutsugamushi 감염에 의한 사람 제대정맥 내피세포에서 부착분자 발현의 변화)

  • Lee, Eun-Bong;Han, Seung-Hoon;Kim, Sang-Wook;Ihn, Kyung-Soo;Seong, Seung-Yong;Kim, Ik-Sang;Choi, Myung-Sik
    • The Journal of the Korean Society for Microbiology
    • /
    • v.35 no.2
    • /
    • pp.159-169
    • /
    • 2000
  • Scrub typhus is caused by Orientia tsutsugamushi characterized by fever, headache, lymphadenopathy and eschar formation. Infiltration of inflammatory cells around blood vessels and within the affected organs isS known to be pathologic hallmark of the scrub typhus. Recently, expression of adhesion molecules on vascular endothelial cells was implicated as an important pathogenic mechanism in rickettsial disease. This study was performed to examine the expression of adhesion molecules and to investigate its role in the pathogenesis of O. tsutsugamushi infection. The expression of adhesion molecules on human umbilical vein endothelial cells (HUVEC) was measured by flow cytometry and indirect immunofluorescence. Expression of E-selectin, ICAM-1 and VCAM-1 was significantly increased 4 hours after the infection and persisted at least for 24 hours. Expression of those molecules was not induced by killed O. tsutsugamushi. Adhesion of polymorphonuclear cells and mononuclear cells to HUVEC was increased after the infection with O. tsutsugamushi. In conclusion, adhesion molecules are expressed on HUVEC during the infection of live O. tsutsugamushi and those molecules can contribute to the infiltration of inflammatory cells during the infection.

  • PDF