<i>Bacillus licheniformis</i> Isolated from Traditional Korean Food Resources Enhances the Longevity of <i>Caenorhabditis elegans</i> through Serotonin Signaling

In this study, we investigated potentially probiotic <i>Bacillus licheniformis</i> strains isolated from traditional Korean food sources for ability to enhance longevity using the nematode <i>Caenorhabditis elegans</i> as a simple in vivo animal model. We first investigated whether <i>B. licheniformis</i> strains were capable of modulating the lifespan of <i>C. elegans</i>. Among the tested strains, preconditioning with four <i>B. licheniformis</i> strains significantly enhanced the longevity of <i>C. elegans</i>. Unexpectedly, plate counting and transmission electron microscopy (TEM) results indicated that <i>B. licheniformis</i> strains were not more highly attached to the <i>C. elegans</i> intestine compared with <i>Escherichia coli</i> OP50 or <i>Lactobacillus rhamnosus</i> GG controls. In addition, qRT-PCR and an aging assay with mutant worms showed that the conditioning of <i>B. licheniformis</i> strain 141 directly influenced genes associated with serotonin signaling in nematodes, including <i>tph-1</i> (tryptophan hydroxylase), <i>bas-1</i> (serotonin- and dopamine-synthetic aromatic amino acid decarboxylase), <i>mod-1</i> (serotonin-gated chloride channel), <i>ser-1</i>, and <i>ser-7</i> (serotonin receptors) during <i>C. elegans</i> aging. Our findings suggest that <i>B. licheniformis</i> strain 141, which is isolated from traditional Korean foods, is a probiotic generally recognized as safe (GRAS) strain that enhances the lifespan of <i>C. elegans</i> via host serotonin signaling

<i>Bacillus licheniformis</i> Isolated from Traditional Korean Food Resources Enhances the Longevity of <i>Caenorhabditis elegans</i> through Serotonin Signaling

In this study, we investigated potentially probiotic <i>Bacillus licheniformis</i> strains isolated from traditional Korean food sources for ability to enhance longevity using the nematode <i>Caenorhabditis elegans</i> as a simple in vivo animal model. We first investigated whether <i>B. licheniformis</i> strains were capable of modulating the lifespan of <i>C. elegans</i>. Among the tested strains, preconditioning with four <i>B. licheniformis</i> strains significantly enhanced the longevity of <i>C. elegans</i>. Unexpectedly, plate counting and transmission electron microscopy (TEM) results indicated that <i>B. licheniformis</i> strains were not more highly attached to the <i>C. elegans</i> intestine compared with <i>Escherichia coli</i> OP50 or <i>Lactobacillus rhamnosus</i> GG controls. In addition, qRT-PCR and an aging assay with mutant worms showed that the conditioning of <i>B. licheniformis</i> strain 141 directly influenced genes associated with serotonin signaling in nematodes, including <i>tph-1</i> (tryptophan hydroxylase), <i>bas-1</i> (serotonin- and dopamine-synthetic aromatic amino acid decarboxylase), <i>mod-1</i> (serotonin-gated chloride channel), <i>ser-1</i>, and <i>ser-7</i> (serotonin receptors) during <i>C. elegans</i> aging. Our findings suggest that <i>B. licheniformis</i> strain 141, which is isolated from traditional Korean foods, is a probiotic generally recognized as safe (GRAS) strain that enhances the lifespan of <i>C. elegans</i> via host serotonin signaling