Ladda Boonyarut, Theparee Talent, Chimchang Juntana, Tanasupawat Somboon, Taweechotipatr Malai
Molecular Biology Program, Faculty of Medicine, Srinakharinwirot University, Thailand.
Department of Microbiology, Faculty of Medicine, Srinakharinwirot University, Thailand.
Anaerobe. 2015 Jun;33:109-16. doi: 10.1016/j.anaerobe.2015.03.002. Epub 2015 Mar 7.
The human microbiota is a source of probiotics capable of modulating the host immune system. In this study, we collected fecal samples from 100 healthy infants and isolated lactic acid bacteria which were screened for immune modulating effects on tumor necrosis factor α (TNF-α) production. Cell-free culture supernatants from 26 isolates were able to decrease TNF-α production in vitro and three of the isolates were selected as candidate probiotics (MSMC39-1, MSMC39-3, MSMC57-1). These isolates were identified using 16S ribosomal DNA sequencing as Lactobacillus paracasei, Lactobacillus casei, and Weissella confusa respectively. All three isolates were acid tolerant and bile tolerant to pH 3.0 and 4% bile respectively. Preparations of cell-free culture supernatants were processed and tested, and revealed that cell-free culture supernatants of isolates L. paracasei MSMC39-1, L. casei MSMC39-3, and W. confusa MSMC57-1 decreased the production of TNF-α significantly and were heat resistant. Only L. paracasei MSMC39-1 supernatant was proteinase-K sensitive. The effects of viable bacteria, heat-killed bacteria, and sonicated bacteria were compared. The heat-killed preparations of isolate W. confusa MSMC57-1 decreased the production of TNF-α. Sonicated cell preparations did not significantly alter TNF-α production. For isolates L. paracasei MSMC39-1 and L. casei MSMC39-3, this suggests that a substance in the cell-free culture supernatant may be responsible for in vitro cytokine modulation.
人类微生物群是能够调节宿主免疫系统的益生菌来源。在本研究中，我们收集了100名健康婴儿的粪便样本，并分离出乳酸菌，筛选其对肿瘤坏死因子α（TNF-α）产生的免疫调节作用。26株分离株的无细胞培养上清液能够在体外降低TNF-α的产生，其中三株分离株被选为候选益生菌（MSMC39-1、MSMC39-3、MSMC57-1）。通过16S核糖体DNA测序分别将这些分离株鉴定为副干酪乳杆菌、干酪乳杆菌和困惑魏斯氏菌。所有三株分离株分别对pH 3.0的酸和4%的胆汁具有耐受性。对无细胞培养上清液制剂进行了处理和测试，结果显示，副干酪乳杆菌MSMC39-1、干酪乳杆菌MSMC39-3和困惑魏斯氏菌MSMC57-1分离株的无细胞培养上清液显著降低了TNF-α的产生，并且具有耐热性。只有副干酪乳杆菌MSMC39-1的上清液对蛋白酶K敏感。比较了活菌、热灭活菌和超声破碎菌的作用。困惑魏斯氏菌MSMC57-1分离株的热灭活制剂降低了TNF-α的产生。超声破碎的细胞制剂没有显著改变TNF-α的产生。对于副干酪乳杆菌MSMC39-1和干酪乳杆菌MSMC39-3分离株，这表明无细胞培养上清液中的一种物质可能负责体外细胞因子调节。
