MicrobiologyOpen. 1, 373-380 (2012)

The results of our collaborative research with the Department of Fisheries, Faculty of Agriculture at Kinki University have been published in the MicrobiologyOpen. 

【Objective】

We examined the immunomodulatory effect of heat-killed Enterococcus faecalis TH10 (hk-TH10) on murine macrophage RAW264 cells.

【Methods】

We measured the amount of nitric oxide (NO) produced from a cell in order to examine the macrophage activity which is an index of activation of the innate immune system. We utilized Toll-like receptors (TLRs) which were knocked down by small interfering RNA (siRNA) in order to determine the pathway in cells where hk-TH10 stimulates macrophage activity.

【Results】

When we set lipopolysaccharides (LPS) which are known to be an enhancer of NO production in cells as a positive control, hk-TH10 stimulated NO production up to a level that is almost half of what LPS does. LPS is a strong enhancer. Therefore, we consider that hk-TH10 has a moderate macrophage activation potency.

According to the result from the experiment using siRNA, macrophage RAW264 cells recognized the passage of hk-TH10 through TLR-2 and TLR-6 pathways, and hk-TH10 stimulated NO production via the activation of NF-kB.    

Biocontrol Science. 9, 77-81 (2004)

The results of a collaborative research with the faculty of Agriculture at Okayama University have been published in the Biocontrol Science. 

【Objective】

The culture fluid of E. faecalis TH10 isolated from tempeh showed a high antibacterial activity against various kinds of disease-causing germs. In this test, we tried to identify and refine the substance which contributed to the antibacterial activity.

【Methods】

We extract culture supernatant of E.faecalis TH10 with solvents and examined its fractions which has the antibacterial activity by reversed phase high-performance liquid chromatography (reversed phase HPLC). Subsequently, we performed gas chromatography-mass spectrometry (GC/MS ) to identify an antibacterial agent.

【Results】

Based on the test about fractionating culture supernatant by HPLC, a fraction eluted by 80% methanol showed a high antibacterial activity against MRSA and the Eschericha coli O-157. As a result of the identification test, E.faecalis TH10 produces phenyllactic acid and the ratio of D- and L-rotatory phenyllactic acid was 2:1. The lactic acid bacteria which produce D- and L-rotatory at the same time have not been found before, so we found this is the original characteristic of E. faecalis TH10 and it suggested that E. faecalis TH10 contributed to high antibiotic action.    

J Biosci Bioenginer 98, 187-192 (2004)

【Objective】

We examined the herb products fermented with lactic acid bacteria in order to understand their inhibitory activity against phytopathogenic filamentous fungi and their effect to the growth of host plants.

【Methods】

We performed an antibacterial activity test on the lactic fermented herb products such as Rosellinia necatrix, Helicobasidium mompa, Fusarium oxysporum, Pythium graminicola and Pyricularia oryzae. We also germinated seeds of alfalfa, asparagus, Komatsuna (Japanese mustard spinach), rice, spinach, tall fescue and tomato on the plates containing 0.69 mg/ml of the dried lactic fermented herb products.

【Results】

The lactic fermented herb products inhibited almost 100% the growth of phytopathogenic filamentous fungi like R. necatrix, H. mompa, P. graminicola and P. oryzae. They inhibited 65% of the growth of F. oxysporum. While they inhibited the growth of the phytopathogenic filamentous fungi, they did not affect to the germinating rate of the seeds of host plants.