Adewoye L O, Worobec E A
Department of Microbiology, University of Manitoba, Winnipeg, Canada.
Can J Microbiol. 1999 Dec;45(12):1033-42.
In response to low extracellular glucose concentration, Pseudomonas aeruginosa induces the expression of the outer membrane carbohydrate-selective OprB porin. The promoter region of the oprB gene was cloned into a lacZ transcriptional fusion vector, and the construct was mobilized into P. aeruginosa OprB-deficient strain, WW100, to evaluate additional environmental factors that influence OprB porin gene expression. Growth temperature, pH of the growth medium, salicylate concentration, and carbohydrate source were found to differentially influence porin expression. This expression pattern was compared to those of whole-cell [14C]glucose uptake under conditions of high osmolarity, ionicity, variable pH, growth temperatures, and carbohydrate source. These studies revealed that the high-affinity glucose transport genes are down-regulated by salicylic acid, differentially regulated by pH and temperature, and are specifically responsive to exogenous glucose induction.
为响应细胞外低葡萄糖浓度，铜绿假单胞菌会诱导外膜碳水化合物选择性孔蛋白OprB的表达。将oprB基因的启动子区域克隆到一个lacZ转录融合载体中，并将构建体导入铜绿假单胞菌OprB缺陷菌株WW100，以评估影响OprB孔蛋白基因表达的其他环境因素。发现生长温度、生长培养基的pH值、水杨酸盐浓度和碳水化合物来源对孔蛋白表达有不同影响。将这种表达模式与在高渗透压、离子强度、可变pH值、生长温度和碳水化合物来源条件下全细胞[14C]葡萄糖摄取的表达模式进行了比较。这些研究表明，高亲和力葡萄糖转运基因受水杨酸下调，受pH值和温度差异调节，并对外源葡萄糖诱导有特异性反应。
