Turner Mark S, Waldherr Florian, Loessner Martin J, Giffard Philip M
Infectious Diseases Program, School of Life Sciences, Faculty of Science, Queensland University of Technology, G.P.O. Box 2434, Brisbane, Queensland 4001, Australia.
Syst Appl Microbiol. 2007 Jan;30(1):58-67. doi: 10.1016/j.syapm.2006.01.013. Epub 2006 Feb 21.
The expression and secretion signals of the Sep protein from Lactobacillus fermentum BR11 were used to direct export of two peptidoglycan hydrolases by Lb. fermentum BR11, Lactobacillus rhamnosus GG, Lactobacillus plantarum ATCC 14917 and Lactococcus lactis MG1363. The production levels, hydrolytic and bacteriocidal activities of the Listeria monocytogenes bacteriophage N-acetylmuramoyl-l-alanine amidase endolysin Ply511 and the glycylglycine endopeptidase lysostaphin were examined. Buffering of the growth media to a neutral pH allowed detection of Ply511 and lysostaphin peptidoglycan hydrolytic activity from all lactic acid bacteria. It was found that purified Ply511 has a pH activity range similar to that of lysostaphin with both enzymes functioning optimally under alkaline conditions. Supernatants from lactobacilli expressing lysostaphin reduced viability of methicillin resistant Staphylococcus aureus (MRSA) by approximately 8 log(10) CFU/ml compared to controls. However, supernatants containing Ply511 were unable to control L. monocytogenes growth. In coculture experiments, both Lb. plantarum and Lb. fermentum synthesizing lysostaphin were able to effectively reduce MRSA cell numbers by >7.4 and 1.7 log(10)CFU/ml, respectively, while lactic acid bacteria secreting Ply511 were unable to significantly inhibit the growth of L. monocytogenes. Our results demonstrate that lysostaphin and Ply511 can be expressed in an active form from different lactic acid bacteria and lysostaphin showed superior killing activity. Lactobacilli producing lysostaphin may have potential for in situ biopreservation in foodstuffs or for prevention of S. aureus infections.
来自发酵乳杆菌BR11的Sep蛋白的表达和分泌信号被用于指导发酵乳杆菌BR11、鼠李糖乳杆菌GG、植物乳杆菌ATCC 14917和乳酸乳球菌MG1363输出两种肽聚糖水解酶。检测了单核细胞增生李斯特菌噬菌体N - 乙酰胞壁酰 - L - 丙氨酸酰胺酶内溶素Ply511和甘氨酰甘氨酸内肽酶溶葡萄球菌素的产量水平、水解活性和杀菌活性。将生长培养基缓冲至中性pH值可检测到所有乳酸菌的Ply511和溶葡萄球菌素的肽聚糖水解活性。结果发现，纯化的Ply511的pH活性范围与溶葡萄球菌素相似，两种酶在碱性条件下功能最佳。与对照相比，表达溶葡萄球菌素的乳酸菌上清液可使耐甲氧西林金黄色葡萄球菌（MRSA）的活力降低约8 log(10) CFU/ml。然而，含有Ply511的上清液无法控制单核细胞增生李斯特菌的生长。在共培养实验中，合成溶葡萄球菌素的植物乳杆菌和发酵乳杆菌分别能够有效降低MRSA细胞数量>7.4和1.7 log(10)CFU/ml，而分泌Ply511的乳酸菌无法显著抑制单核细胞增生李斯特菌的生长。我们的结果表明，溶葡萄球菌素和Ply511可以在不同的乳酸菌中以活性形式表达，并且溶葡萄球菌素显示出更强的杀伤活性。产生溶葡萄球菌素的乳酸菌在食品原位生物保存或预防金黄色葡萄球菌感染方面可能具有潜力。
