Phytopathology. 2000 Jul;90(7):716-22. doi: 10.1094/PHYTO.2000.90.7.716.
ABSTRACT Two microtiter plate assays were developed to study the adherence of the plant-pathogenic mollicute Spiroplasma citri to a monolayer of cultured cells of its leafhopper vector, Circulifer tenellus. Adherence was significantly reduced by prior treatment of the spiroplasmas with proteinase K or pronase. Electrophoresis and western blotting of spiroplasma membrane proteins, before and after exposure of intact spiroplasmas to proteases, revealed the concomitant reduction in intensity of a major membrane protein (P89) and a new polypeptide of approximately 46 kDa in protease-treated preparations (P46). Triton X-114 phase partitioning demonstrated that P89 and P46 are amphiphilic, and labeling of the new polypeptide P46 with anti-P89 serum suggested that this molecule may be a breakdown product of P89. Regeneration of P89 after proteinase K treatment of spiroplasmas was directly associated with restoration of the pathogen's attachment capability. Treatment of spiroplasmas with any of several carbohydrates and glycoconjugates or with tetramethyl-urea, a compound that interferes with hydrophobic associations, had a negligible effect on attachment. These results suggest that a spiroplasma surface protein, P89, has a role in S. citri adherence to C. tenellus cells.
两个微量滴定板测定法被开发出来，以研究植物致病柔膜体菌柑橘僵化螺菌对其叶蝉载体Circulifer tenellus 培养细胞单层的附着。用蛋白酶 K 或链霉蛋白酶预先处理螺旋体，附着显著减少。未处理的完整螺旋体暴露于蛋白酶前后的螺旋体膜蛋白的电泳和 Western 印迹显示，主要膜蛋白（P89）和蛋白酶处理制剂中的新约 46 kDa 多肽的强度同时降低（P46）。Triton X-114 相分离表明 P89 和 P46 是两亲性的，并且用抗 P89 血清标记新的多肽 P46 表明该分子可能是 P89 的分解产物。蛋白酶 K 处理螺旋体后 P89 的再生与病原体附着能力的恢复直接相关。用几种碳水化合物和糖缀合物或四甲基脲（一种干扰疏水性结合的化合物）处理螺旋体对附着几乎没有影响。这些结果表明，螺旋体表面蛋白 P89 在 S. citri 附着到 C. tenellus 细胞中起作用。
