Microarray analysis of a two-component regulatory system involved in acid resistance and proteolytic activity in Lactobacillus acidophilus
Microarray analysis of a two-component regulatory system involved in acid resistance and proteolytic activity in Lactobacillus acidophilus
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DOI：
10.1128/aem.71.10.5794-5804.2005
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发表时间：
2005-10-01
影响因子：
4.4
通讯作者：
Klaenhammer, TR
中科院分区：
文献类型：
--
作者：
Azcarate-Peril, MA;McAuliffe, O;Klaenhammer, TR
双组分调控系统是环境感知和信号转导的一种主要机制。对益生菌嗜酸乳杆菌NCFM全基因组序列的注释揭示了9个双组分调控系统。在本研究中，与单核增生李斯特菌酸相关系统lisRK （P. D. Cotter et al.， J. Bacteriol. 181:6840-6843, 1999）相似，双组分调控系统（LBA1524HPK-LBA1525RR）的组氨酸蛋白激酶被插入失活。利用含有97.4%嗜酸乳杆菌注释基因的全基因组微阵列，比较了对照组和组氨酸蛋白激酶突变体在不同ph值下的全基因组转录模式。LBA1524HPK突变影响了大约80个基因的表达模式。假定的LBA1525RR靶位点包括乳杆菌基因组中存在的两个寡肽运输系统，蛋白质水解系统的其他组分，以及LuxS同源物，怀疑参与AI-2信号化合物的合成。该突变体在对数期细胞中对酸和乙醇的耐受性较低，在牛奶中酸化率较低。在牛奶中添加Casamino Acids基本上恢复了突变体的产酸能力，为这两组分系统在调节嗜酸乳杆菌蛋白水解活性中的作用提供了额外的证据。
Two-component regulatory systems are one primary mechanism for environmental sensing and signal transduction. Annotation of the complete genome sequence of the probiotic bacterium Lactobacillus acidophilus NCFM revealed nine two-component regulatory systems. In this study, the histidine protein kinase of a two-component regulatory system (LBA1524HPK-LBA1525RR), similar to the acid-related system lisRK from Listeria monocytogenes (P. D. Cotter et al., J. Bacteriol. 181:6840-6843, 1999), was insertionally inactivated. A whole-genome microarray containing 97.4% of the annotated genes of L. acidophilus was used to compare genome-wide patterns of transcription at various pHs between the control and the histidine protein kinase mutant. The expression pattern of approximately 80 genes was affected by the LBA1524HPK mutation. Putative LBA1525RR target loci included two oligopeptide-transport systems present in the L. acidophilus genome, other components of the proteolytic system, and a LuxS homolog, suspected of participating in synthesis of the AI-2 signaling compound. The mutant exhibited lower tolerance to acid and ethanol in logarithmic-phase cells and poor acidification rates in milk. Supplementation of milk with Casamino Acids essentially restored the acid-producing ability of the mutant, providing additional evidence for a role of this two component system in regulating proteolytic activity in L. acidophilus.