• 제목/요약/키워드: U-phase

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Analysis of Catalases from Photosynthetic Bacterium Rhodospirillum rubrum Sl

  • Lim, Hee-Kyung;Kim, Young-Mi;Lee, Dong-Heon;Kahng, Hyung-Yeel;Oh, Duck-Chul
    • Journal of Microbiology
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    • 제39권3호
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    • pp.168-176
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    • 2001
  • Five different types of catalases from photosynthetic bacterium Rhodospirillum rubrum S1 grown aerobically in the dark were found in this study, and designated Catl (350 kDa), Cat2 (323 kDa), Cat3 (266 kDa), Cat4 (246 kDa), and Cat5 (238 kDa). Analysis of native PAGE revealed that Cat2, Cat3, and Cat4 were also produced in the cells anaerobically grown in the light. It is notable that only Cat2 was expressed much more strongly in response to the anaerobic condition. Enzyme activity staining demonstrated that Cat3 and Cat4 had bifunctional catalase-peroxidase activities, while Catl, Cat2, and Cat5 were typical monofunctional catalases. S1 cells grown aerobically in the presence of malate as the sole source of carbon exhibited an apparent catalase Km value of 10 mM and a Vmax of about 705 U/mg protein at late stationary growth phase. The catalase activity of Sl cells grown in the anaerobic environment exhibited a much lower Vmax of about 109 U/mg protein at late logarithmic growth phase. The catalytic activity was stable in the broad range of temperatures (30$\^{C}$-60$\^{C}$), and pH (6.0-10.0). R. rubrum S1 was much more resistant to H$_2$O$_2$in the stationary growth phase than in the exponential growth phase regardless of growth conditions. Cells of stationary growth phase treated with 15 mM H$_2$O$_2$for 1 h showed 3-fold higher catalase activities than the untreated cells. In addition, L-glutamate induced an 80-fold increase in total catalase activity of R. rubrum S1 compared with magic acid. Through fraction analyses of S1 cells, Cat2, Cat3, Cat4 and Cat5 were found in both cytoplasm and periplasm, while Catl was localized only in the cytoplasm.

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인체거대세포바이러스에 의한 인체 단핵구세포의 세포주기 저해 (Cell Cycle Arrest in Human Monocyte Cell Line by Human Cytomegalovirus)

  • 장소영;김미숙;이찬희
    • 미생물학회지
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    • 제44권4호
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    • pp.299-304
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    • 2008
  • 마이엘로이드 계열의 단핵세포는 인체세포거대바이러스(human cytomegalovirus, HCMV)의 잠복 부위로 알려져 있다. 다양한 세포에서 HCMV에 의한 세포주기의 촉진 또는 억제에 관한 연구는 많이 있었지만, 단핵세포에서의 연구는 거의 없는 상태이다. 이에 본 연구에서는 단핵세포에 HCMV가 감염되면 세포주기에 어떤 변화가 나타나는지 알아보고자 하였다. Propidium iodide를 이용한 유세포 분석을 통한 세포주기 분석에서 HCMV에 감염된 THP-1 세포에서는 G0-G1기가 증가하고, 그만큼 S가 감소함을 보았다. 반면 HL-60 세포에서는G0-G1기와 S기의 상대적인 비율에 큰 변화가 없었다. BrdU 유입 실험에서 THP-1세포의 DNA 합성이 HCMV 감염에 의해 억제됨을 알 수 있었다. 세포주기의 G1기에서 S기로의 전환을 억제하는 p21 단백질은HCMV에 감염된 THP-1 세포에서는 발현이 유도되었지만 HL-60 세포에서는 거의 발현이 되지 않았다. 따라서 HCMV는 promocyte THP-1 세포에서 p21 단백질의 유도에 의해 세포주기를 G0-G1기에서 억류함에 따라 세포중식을 억제하는 것으로 생각된다.