背景:嗜水气单胞菌是一种致病细菌,可在人和动物中引起各种感染。细菌外蛋白酶被认为是嗜水曲霉致病性的重要决定因素。丝氨酸蛋白酶和金属蛋白酶,受细菌群体感应(QS)系统调节的是嗜水菌致病性的重要毒力因子。姜黄素的抗QS潜力已有报道,以前。在这项工作中,我们研究了姜黄素对嗜水气单胞菌金属蛋白酶和丝氨酸蛋白酶基因表达的影响。
方法:通过琼脂宏观稀释法测量姜黄素的最小抑制浓度(MIC),并在随后的实验中使用亚抑制浓度(1/2MIC)。使用定量PCR(qPCR)测定评估处理的细菌和对照细菌中金属蛋白酶和丝氨酸蛋白酶基因的表达水平。还通过脱脂乳琼脂平板测定法测量细菌蛋白水解活性。
结果:姜黄素对细菌菌株的MIC为1024μg/ml姜黄素,在512µg/mL(1/2MIC)时,它显着降低了金属蛋白酶和丝氨酸蛋白酶基因的表达,达到66%和77%,分别。此外,姜黄素大大降低了嗜水气单胞菌的蛋白水解活性。
结论:由于对细菌蛋白水解具有良好的抑制作用,姜黄素可以被认为是针对嗜水气单胞菌的抗毒剂。
BACKGROUND: Aeromonas hydrophila is a pathogenic bacterium responsible for various infections in humans and animals. Bacterial exoproteases are considered an important determinant in the pathogenicity of A. hydrophila. Serine protease and
metalloprotease, that are regulated by the bacterial Quorum sensing (QS) system are important virulent factors in the pathogenicity of A. hydrophila. Anti-QS potential of curcumin has been reported, previously. In this work, we characterized the effect of curcumin on the expression of the
metalloprotease and serine protease genes in A. hydrophila.
METHODS: The minimum inhibitory concentration (MIC) of curcumin was measured by the agar macro-dilution method and a sub-inhibitory concentration (1/2 MIC) was used in subsequent experiments. The expression level of the
metalloprotease and serine protease genes among the treated and control bacteria was evaluated using quantitative PCR (qPCR) assay. Bacterial proteolytic activity was also measured by skim milk agar plate assay.
RESULTS: MIC of curcumin for bacterial strain was 1024 μg/ml curcumin, and at 512 µg/mL (1/2 MIC) it remarkably attenuated the expression of the
metalloprotease and serine protease genes up to 66 and 77%, respectively. Also, the proteolytic activity of A. hydrophila was considerably reduced by curcumin.
CONCLUSIONS: Due to the promising inhibitory effect on bacterial proteolysis, curcumin could be considered an anti-virulence agent against A. hydrophila.