Immunochemical and biological characterization of three capsular polysaccharides from a single Bacteroides fragilis strain
Immunochemical and biological characterization of three capsular polysaccharides from a single Bacteroides fragilis strain
复制标题
DOI：
10.1128/iai.69.4.2339-2344.2001
复制
发表时间：
2001-04-01
影响因子：
3.1
通讯作者：
Kasper, DL
中科院分区：
文献类型：
--
作者：
Kalka-Moll, WM;Wang, Y;Kasper, DL
虽然脆弱拟杆菌仅占正常人结肠植物群的0.5%，但它是最常从腹腔内和其他肠源感染中分离的厌氧菌种。B.脆弱菌是表面多糖复合物的一部分，并且是生物体在形成腹腔内脓肿中最重要的毒力因子。来自菌株NCTC 9343的两种荚膜多糖PS Al和PS Bl已经在结构上表征。它们最显著的特征是在每个重复单元上由带正电荷和负电荷的取代基组成的两性离子电荷基序。这种两性离子基序对于脓肿的形成是必不可少的。在这项研究中，我们试图阐明一个常用的研究B的荚膜多糖复合物的结构特征。fragilis菌株，638 R，其不同于菌株9343。我们寻求一个更普遍的图片的物种，以建立基本的结构活性和结构生物合成之间的关系，诱导产酸多糖。发现菌株638 R具有荚膜多糖复合物，通过复杂的纯化程序可以从该复合物中分离出三种不同的碳水化合物。成分和免疫化学研究表明，两性离子电荷基序共同所有的荚膜多糖，与他们的能力，诱导实验性腹腔内脓肿。感兴趣的是分离的多糖的净电荷范围-从正电荷（PS C2）到平衡电荷（PS A2）再到负电荷（PS 3）。确定了两性离子多糖的结构组分与其分子生物合成位点之间的关系。
Although Bacteroides fragilis accounts for only 0.5% of the normal human colonic flora, it is the anaerobic species most frequently isolated from intra-abdominal and other infections with an intestinal source. The capsular polysaccharides of B. fragilis are part of a complex of surface polysaccharides and are the organism's most important virulence factors in the formation of intra-abdominal abscesses. Two capsular polysaccharides from strain NCTC 9343, PS Al and PS B1, have been characterized structurally. Their most striking feature is a zwitterionic charge motif consisting of both positively and negatively charged substituent groups on each repeating unit. This zwitterionic motif is essential far abscess formation. In this study, we sought to elucidate structural features of the capsular polysaccharide complex of a commonly studied B. fragilis strain, 638R, that is distinct from strain 9343. We sought a more general picture of the species to establish basic structure-activity and structure-biosynthesis relationships among abscess-inducing polysaccharides. Strain 638R was found to have a capsular polysaccharide complex from which three distinct carbohydrates could be isolated by a complex purification procedure. Compositional and immunochemical studies demonstrated a zwitterionic charge motif common to all of the capsular polysaccharides that correlated with their ability to induce experimental intra-abdominal abscesses. Of interest is the range of net charges of the isolated polysaccharides-from positive (PS C2) to balanced (PS A2) to negative (PS 3). Relationships among structural components of the zwitterionic polysaccharides and their molecular biosynthesis loci were identified.