Makimura Yutaka, Asai Yasuyuki, Sugiyama Akiko, Ogawa Tomohiko
Department of Oral Microbiology, Asahi University School of Dentistry, 1851-1 Hozumi, Mizuho, Gifu 501-0296, Japan.
J Med Microbiol. 2007 Nov;56(Pt 11):1440-1446. doi: 10.1099/jmm.0.47327-0.
The chemical structure and immunobiological activities of Serratia marcescens lipid A, an active centre of LPS, were investigated. LPS preparations of S. marcescens were extracted using a hot phenol/water method, after which purified lipid A specimens were prepared by weak acid hydrolysis, followed by normal phase and gel filtration chromatographic separation. The lipid A structure was determined by MS to be a diglucosamine backbone with diphosphates and five C(14) normal chain acyl groups, including two acyloxyacyl groups at the 2 and 3 positions of the non-reducing side. S. marcescens lipid A and Escherichia coli-type synthetic lipid A (compound 506) exhibited definite reactivity in Limulus amoebocyte lysate assays. The lethal toxicity of S. marcescens lipid A was nearly comparable to that of compound 506, and both induced nuclear factor-kappaB activation in murine cells via Toll-like receptor (TLR)4/MD-2 but not TLR2, as well as various inflammatory cytokines in peritoneal macrophages of C3H/HeN mice but not C3H/HeJ mice. Furthermore, S. marcescens lipid A induced nearly the same amounts of tumour necrosis factor alpha, interleukin-6, and nitric oxide production by the murine alveolar macrophage cell line MH-S as compared with compound 506. These results indicate that S. marcescens possesses a penta-acylated lipid A, which is nearly identical to E. coli lipid A in regard to biological activities, while it also may be a crucial virulence factor of the bacterium.
研究了粘质沙雷氏菌脂多糖（LPS）活性中心——粘质沙雷氏菌脂多糖A的化学结构和免疫生物学活性。采用热酚/水法提取粘质沙雷氏菌的LPS制剂，然后通过弱酸水解制备纯化的脂多糖A标本，随后进行正相和凝胶过滤色谱分离。通过质谱法确定脂多糖A的结构为具有二磷酸酯和五个C(14)正链酰基的二葡糖胺主链，包括在非还原侧2和3位的两个酰氧基酰基。粘质沙雷氏菌脂多糖A和大肠杆菌型合成脂多糖A（化合物506）在鲎试剂检测中表现出一定的反应性。粘质沙雷氏菌脂多糖A的致死毒性与化合物506几乎相当，两者均通过Toll样受体（TLR）4/MD-2而非TLR2在鼠细胞中诱导核因子-κB活化，以及在C3H/HeN小鼠而非C3H/HeJ小鼠的腹腔巨噬细胞中诱导多种炎性细胞因子。此外，与化合物506相比，粘质沙雷氏菌脂多糖A诱导鼠肺泡巨噬细胞系MH-S产生的肿瘤坏死因子α、白细胞介素-6和一氧化氮的量几乎相同。这些结果表明，粘质沙雷氏菌具有一种五酰化脂多糖A，其在生物学活性方面与大肠杆菌脂多糖A几乎相同，同时它也可能是该细菌的关键毒力因子。
