Shakya Shrijana, Danshiitsoodol Narandalai, Noda Masafumi, Inoue Yusuke, Sugiyama Masanori
Department of Probiotic Science for Preventive Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Front Microbiol. 2022 Sep 23;13:991144. doi: 10.3389/fmicb.2022.991144. eCollection 2022.
In the present study, the effect of PLA on a periodontic pathogen, (), the biofilm, and virulence-related genes was investigated. We confirmed that two lactic acid bacteria (LAB) strains isolated from plant sources, MSC-C2 and K40, secrete PLA into the de Man, Rogosa & Sharpe (MRS) broth when supplemented with phenyl pyruvic acid (PPA) as a precursor to PLA. Moreover, PLA was generated in the fermentation broths of two medicinal plant extracts, Pall (PR) and (CT), when used by each LAB strain and each extract supplemented with PPA. We determined that the minimum inhibitory concentration (MIC) of PLA against was 20 mM. PLA significantly decreased biofilm formation and suppressed the transcription of , , and genes, which encode the poly-N-acetylglucosamine (PGA) polysaccharide of biofilm matrix and exotoxins leukotoxin and cytolethal distending toxin (CDT), respectively. The PLA produced by the MSC-C2 and K40 strains was increased several times by the addition of PPA to the MRS broth. The anti-biofilm effect of the extracts from the fermentation broth was proportional to the increasing PLA concentration, while a cumulatively higher effect than that of PLA alone suggested a combinational effect of PLA and the other metabolites, such as lactic acid (LA). Among the two medicinal plants, PLA, produced after the addition of PPA, was higher in PR extract in case of both the LAB strains. PLA production by the MSC-C2 strain in the PR extract reached 4.8 ± 0.23 mM, which was obviously higher than that in the MRS broth (3.88 ± 0.12 mM) supplemented with 1 mg/ml PPA. The activity to inhibit biofilm formation in the fermented PR extract was clearly high. PLA formed in the fermented PR extract downregulated the dispersin B encoding the gene together with , , and . In conclusion, this study shows a promising activity of PLA against the biofilm and virulence genes. In addition, the combinational effect of PLA and the medicinal plant extract can be achieved by fermentation with a specific plant-derived LAB strain.
在本研究中，研究了聚乳酸（PLA）对一种牙周病原体（）、生物膜及毒力相关基因的影响。我们证实，从植物源分离出的两株乳酸菌（LAB），即MSC - C2和K40，在以苯丙酮酸（PPA）作为聚乳酸前体添加到德氏、罗氏和夏普培养基（MRS肉汤）中时，会分泌聚乳酸。此外，当每种乳酸菌菌株使用两种药用植物提取物，即白首乌（PR）和（CT）并添加PPA时，在发酵液中产生了聚乳酸。我们测定聚乳酸对的最低抑菌浓度（MIC）为20 mM。聚乳酸显著降低生物膜形成，并抑制、和基因的转录，这三个基因分别编码生物膜基质的聚 - N - 乙酰葡糖胺（PGA）多糖以及外毒素白细胞毒素和细胞致死性膨胀毒素（CDT）。通过向MRS肉汤中添加PPA，MSC - C2和K40菌株产生的聚乳酸增加了数倍。发酵液提取物的抗生物膜作用与聚乳酸浓度的增加成正比，而比单独聚乳酸累积更高的作用表明聚乳酸与其他代谢产物，如乳酸（LA）存在联合作用。在这两种药用植物中，添加PPA后产生的聚乳酸在两种乳酸菌菌株的情况下，在PR提取物中更高。PR提取物中MSC - C2菌株产生的聚乳酸达到4.8±0.23 mM，明显高于添加1 mg/ml PPA的MRS肉汤中的聚乳酸（3.88±0.12 mM）。发酵后的PR提取物中抑制生物膜形成的活性明显较高。发酵后的PR提取物中形成的聚乳酸与、和一起下调了编码基因的分散素B。总之，本研究表明聚乳酸对生物膜和毒力基因具有良好的作用。此外，聚乳酸与药用植物提取物的联合作用可通过与特定植物源乳酸菌菌株发酵来实现。
