In the present study, we assessed the ability of MALDI-TOF MS (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) to identify microbial strains subjected to high hydrostatic pressure (HHP) as a stress factor. Protein changes induced by HHP can affect the identification of microorganisms when the identification technique is based on the protein profile. We evaluated two methods, namely MALDI-TOF MS and 16S rDNA sequencing, as a valuable tool to identify Lactobacillus species isolated from spoiled food, juices and beers. The data obtained from the protein mass fingerprint analysis of some of the lactobacilli strains showed differences in unpressured and pressured mass spectrum profiles (MSPs), which influenced the results of the identification. Four out of 13 strains (30%) showed different MSP results for unpressured and pressured samples and these results did not overlap with the 16S rDNA identification results. The 16S rDNA sequencing method revealed that five unpressured strains (38%) and four pressured strains (40%) were identified correctly by MALDI-TOF MS. Both methods showed compatible results in 38% of unpressured strains and in 30% of pressured strains. Stress factors, cultivation methods or the natural environment from which the bacteria were derived can affect their protein profile and thus change the mass spectrum. It is necessary to expand the database with a wide range of mass spectra dedicated to a high-throughput study of the microorganisms derived from different environments.

中文翻译：

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高静水压对 MALDI-TOF MS 鉴定乳酸菌的影响 - 初步研究。

在本研究中，我们评估了 MALDI-TOF MS（基质辅助激光解吸电离飞行时间质谱）识别高静水压 (HHP) 作为应激因素的微生物菌株的能力。当鉴定技术基于蛋白质谱时，HHP 引起的蛋白质变化会影响微生物的鉴定。我们评估了两种方法，即 MALDI-TOF MS 和 16S rDNA 测序，作为鉴定从变质食品、果汁和啤酒中分离出的乳酸菌物种的有价值的工具。一些乳酸杆菌菌株的蛋白质质量指纹图谱分析获得的数据显示，无压和加压质谱图（MSP）存在差异，这影响了鉴定结果。13 个菌株中有 4 个 (30%) 对于未受压和受压样品显示出不同的 MSP 结果，并且这些结果与 16S rDNA 鉴定结果不重叠。16S rDNA测序方法显示，MALDI-TOF MS正确鉴定了5种非加压菌株（38%）和4种加压菌株（40%）。两种方法在 38% 的未受压应变和 30% 的受压应变中显示出一致的结果。应激因素、培养方法或细菌来源的自然环境都会影响其蛋白质谱，从而改变质谱。有必要通过广泛的质谱来扩展数据库，致力于对来自不同环境的微生物进行高通量研究。