Aditya Arpita, Li Yue, Biswas Debabrata
Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland 20742, USA.
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
J Food Prot. 2022 Apr 1;85(4):712-719. doi: 10.4315/JFP-21-414.
Probiotics in fermented foods or commercially available supplements benefit the host by providing metabolites and peptides. The production of these metabolites varies with the available substrates or prebiotics present in the system and their concentration. In this study, 0.5% peanut flour (PF) was used to stimulate the growth and production of metabolites of wild-type Lactobacillus casei (LCwt) and compare with an engineered L. casei (LCCLA) capable of converting a higher amount of conjugated linoleic acid (CLA). The total extracellular metabolites present in the cell-free cultural supernatant (CFCS) of LCwt (without peanut), LCwt+PF (with peanut), and LCCLA were collected after 24 and 48 h of incubation, and their antagonistic activities against enterohemorrhagic Escherichia coli (EHEC EDL933) growth and pathogenesis were evaluated. All collected metabolites exhibited varying efficiency in restraining EHEC EDL933 growth, whereas supplementing a low concentration of CLA to the 48-h CFCS from LCwt showed augmented antagonism toward EHEC EDL933. A downregulation of key virulence genes was observed from metabolites collected at the 48-h time point. These observations indicate that the presence of metabolites in CFCSs-including CLA, which is produced by Lactobacillus and was identified by gas chromatography-mass spectrometry-plays a critical role. This study demonstrates the potential applicability of Lactobacillus-originated CLA in the prevention of EHEC EDL933-mediated illnesses.
发酵食品或市售补充剂中的益生菌通过提供代谢产物和肽类对宿主有益。这些代谢产物的产生随系统中可用的底物或益生元及其浓度而变化。在本研究中，使用0.5%的花生粉（PF）刺激野生型干酪乳杆菌（LCwt）代谢产物的生长和产生，并与能够转化更高量共轭亚油酸（CLA）的工程化干酪乳杆菌（LCCLA）进行比较。在培养24小时和48小时后，收集LCwt（无花生）、LCwt+PF（有花生）和LCCLA的无细胞培养上清液（CFCS）中存在的总细胞外代谢产物，并评估它们对肠出血性大肠杆菌（EHEC EDL933）生长和致病机制的拮抗活性。所有收集的代谢产物在抑制EHEC EDL933生长方面表现出不同的效率，而向来自LCwt的48小时CFCS中补充低浓度的CLA显示出对EHEC EDL933增强的拮抗作用。在48小时时间点收集的代谢产物中观察到关键毒力基因的下调。这些观察结果表明，CFCS中的代谢产物——包括由乳杆菌产生并通过气相色谱-质谱法鉴定的CLA——起着关键作用。本研究证明了乳杆菌来源的CLA在预防EHEC EDL933介导的疾病中的潜在适用性。
