Pseudomonas aeruginosa protease IV produces corneal damage and contributes to bacterial virulence.
Pseudomonas aeruginosa protease IV produces corneal damage and contributes to bacterial virulence.
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发表时间：
1998-03
影响因子：
4.4
通讯作者：
Lee S. Engel;James M. Hill;Judy M. Moreau;Linda C. Green;J. A. Hobden;R. O'Callaghan
中科院分区：
文献类型：
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作者：
Lee S. Engel;James M. Hill;Judy M. Moreau;Linda C. Green;J. A. Hobden;R. O'Callaghan
蛋白酶IV缺陷的假单胞菌突变株在实验性角膜炎中的毒力显著降低。在本研究中，分析了纯化的蛋白酶IV的角膜毒性及其增强蛋白酶IV缺陷型细菌毒力的能力。方法将纯化的蛋白酶IV经角膜基质内注射20-200 ng，测定其毒性。蛋白酶IV对蛋白酶IV缺陷型菌株PA 103 -29：：Tn 9的角膜毒力的影响通过向眼睛注射1000 CFU对数期细菌加上200 ng活性纯化蛋白酶IV或200 ng热灭活蛋白酶IV来测定。在感染后3、16、22和27小时，通过裂隙灯检查测定眼部疾病的变化。在感染后27小时定量每个角膜的菌落形成单位。结果纯化的蛋白酶IV在50 - 200 ng的剂量下在注射后3小时内诱导上皮缺损。注射20 ng活性蛋白酶IV或热灭活蛋白酶IV（200 ng）对眼组织没有影响。角膜基质内注射纯化的蛋白酶IV可增强蛋白酶IV缺陷株的角膜毒力，但注射热灭活的蛋白酶IV则无此作用（P <或= 0.0001）。活性或热灭活蛋白酶IV均未改变角膜中细菌的生长（6个对数单位; P = 0.81）。结论：蛋白酶IV在角膜毒力中的重要作用通过直接毒性和其显著增强蛋白酶IV缺陷假单胞菌毒力的能力得到证实。
PURPOSE A Pseudomonas mutant deficient in protease IV has significantly reduced virulence in experimental keratitis. In the present study, the corneal toxicity of purified protease IV and its ability to augment the virulence of protease-IV-deficient bacteria were analyzed. METHODS The toxicity of purified protease IV was determined by intrastromally injecting the exoenzyme (20-200 ng) into the cornea. The effects of protease IV on the corneal virulence of the protease-IV-deficient strain, PA103-29::Tn9, were determined by injecting eyes with 1000 CFU of log phase bacteria plus either 200 ng active purified protease IV or 200 ng heat-inactivated protease IV. Changes in ocular disease, determined by slit-lamp examination, were measured at 3, 16, 22, and 27 hours after infection. Colony-forming units per cornea were quantified at 27 hours after infection. RESULTS Purified protease IV at doses from 50 to 200 ng induced epithelial defects within 3 hours of injection. Injection of 20 ng active protease IV or heat-inactivated protease IV (200 ng) had no effect on ocular tissue. Corneal virulence of the protease-IV-deficient strain was augmented by intrastromal injection with purified protease IV but not with heat-inactivated protease IV (P < or = 0.0001). Neither active nor heat-inactivated protease IV altered the growth of bacteria in the cornea (6 log units; P = 0.81). CONCLUSIONS The important role of protease IV in corneal virulence was demonstrated by direct toxicity and by its ability to significantly augment the virulence of protease-IV-deficient Pseudomonas.