The role of the gut microbiota in colorectal cancer (CRC) development has garnered attention, highlighting probiotics as potential adjuncts in CRC prevention and treatment. In recent years, probiotics and their derivatives have demonstrated mechanisms that may contribute to anticancer properties. This study investigates the cytotoxic effects of Bifidobacterium bifidum KCTC 3357, Lacticaseibacillus rhamnosus KCTC 5033, Limosilactobacillus reuteri VA 103, Bacillus galactosidilyticus VA 107, and Lactococcus taiwanensis VE101 on CT-26 mouse colon carcinoma cells using live cells, heat-killed cells (paraprobiotics), and cell-free supernatants (CFS, postbiotics) through an MTT assay. The results indicate that live bacterial strains, such as KCTC 3357, VA 103, and VA 107, promoted CT-26 cell viability, while heat-killed cells and CFS exhibited dose-dependent cytotoxicity. Inactivated forms of KCTC 3357 and VE 101, as well as CFS at 10 mg/mL concentration of KCTC 5033, VA 103, and VE 101, showed the strongest antiproliferative effects. These findings suggest that non-viable probiotic derivatives, such as paraprobiotics and postbiotics, offer promising therapeutic potential for CRC, providing a safer and more stable alternative to live probiotics. However, further research is required to explore their mechanisms of action, in vivo efficacy, and potential clinical applications.

Probiotics have been evaluated as therapeutic agents for cancer treatment in an increasing number of studies. This study investigated the inhibitory and cytotoxic effects of specific Lactobacillus strains on a human colorectal adenocarcinoma cell line (HT-29). The strains assessed were Limosilactobacillus (L.) reuteri VA 102, Ligilactobacillus (L.) animalis VA 105, and Limosilactobacillus (L.) reuteri KCTC 3594 (ATCC 23272). The viability of HT-29 cells was evaluated using the MTT assay. The findings revealed that cell-free supernatants (CFS) exhibited significant anticancer effects. Heat-inactivated L. reuteri VA 105 and L. reuteri KCTC 3594 induced a pronounced reduction in cell viability. Furthermore, live cultures of L. reuteri VA 105 and L. reuteri VA 102 also showed reduced cell viability compared to the control group. These results suggest that CFS and heat-inactivated cells may be more suitable for therapeutic applications than live bacteria owing to their improved safety profiles and reduced potential for adverse effects. Our findings also emphasize the potential anticancer benefits of these LAB strains.

Probiotic lactic acid bacteria are live microorganisms that provide health benefits when administered in adequate amounts and may exhibit antiproliferative effects on various cancer cell lines, including colon cancer. This study investigates the cytotoxic effects of three Lactobacillus strains - Limosilactobacillus (L.) reuteri VA 102, Ligilactobacillus (L.) animalis VA 105, and Limosilactobacillus (L.) reuteri KCTC 3594 (ATCC 23272) - on mouse colon carcinoma cells (CT-26). Live cells, heat-killed cells, and cell-free supernatant (CFS) of Lactobacillus sp. were prepared and used to treat CT-26 cells at different concentrations. The cytotoxic effect was assessed using the MTT assay. The results indicated that the CFS of all strains significantly reduced the viability of CT-26 cells in a dose-dependent manner, with the VA 102 strain showing the most pronounced effect. Heat-killed cells of L. reuteri VA 102 and L. reuteri KCTC 3594 (ATCC 23272) also reduced cell viability. These findings suggest the potential anticancer properties of these Lactobacillus strains and indicate that CFS and heat-killed cells may offer a safer and more effective alternative to live bacteria for therapeutic applications. Our study contributes to the understanding of the potential of Lactobacillus strains, particularly L. reuteri VA 102, L. reuteri KCTC 3594 (ATCC 23272), and L. animalis VA 105, as possible candidates for cancer treatment and control.

The major innate immune pathways in Asian longhorned ticks, Haemaphysalis longicornis, include Toll, IMD, and JAK/STAT. In the field, H. longicornis can be infected with various pathogens including Severe Fever with Thrombocytopenia Syndrome Virus (SFTS virus), Rickettsia, Babesia and Anaplasma species. One approach to identify whether ticks are infected with pathogens is by examining the expression levels of immune response genes. To evaluate whether upregulation of immune genes from H. longicornis can serve as an indicator for pathogen infection in ticks, we first designed primer sets for Dorsal, STAT, and Relish from the H. longicornis genome. We then conducted quantitative reverse transcription PCR(qRT-PCR) on cDNA of field-collected H. longicornis and identified individuals with high expression levels in immune response genes. Subsequently, we performed digital PCR assays to determine whether selected ticks were infected with SFTS virus. Using this approach, we evaluated correlation between pathogen infection and upregulation of immune response genes in ticks. Although more experiments are needed to draw conclusions, this study suggests immune response gene-based screening methods for pathogen infected ticks from the field.

Two bacterial genera, Xenorhabdus and Photorhabdus, are mutually symbiotic to the entomopathogenic nematodes, Steinernema and Heterorhabditis, respectively. Success parasitism of the nematode-bacterial complex depends on the host immunosuppression by the bacteria via their secondary metabolites. Lrp (Leucine-responsive regulatory protein) is a global transcriptional factor of the bacteria and play a crucial role in the parasitism. However, its regulatory targets to suppress the insect immunity were not clearly determined. This study investigated the regulatory target genes and subsequent secondary metabolites by Lrp in Xenorhabdus hominickii. Lrp expression occurred at the early infection stage in a target insect, Spodoptera exigua. Among eight non-ribosomal peptide synthetase (NRPS1-NRPS8) genes, six gene (NRPS3-NRPS8) expressions were positively correlated with Lrp expression in the infected larvae of S. exigua. Exchange of the Lrp promoter with an inducible promoter altered the production of the secondary metabolites along with alteration of the NRPS expression levels. The immunosuppressive activities of X. hominickii depended on the Lrp expression level. The metabolites produced by Lrp expression possessed the eicosanoid-biosynthesis inhibitors and hemolytic factors. A cyclic dipeptide (= cPF) was produced under Lrp control and identified to inhibit phospholipase A2 activity of S. exigua in a competitive inhibitory manner. These results suggest that Lrp is a global transcriptional factor of X. hominickii and plays crucial role in insect immunosuppression by modulating NRPS expressions.

To investigate the antimicrobial effect of polyphosphates as a food additive, the growth and structural change of Listeria monocytogenes Scott A were examined in relation to polyphosphates concentration and incubation temperature. Up to 10,000 ppm of polyphosphates, the growth rate of strain was gradually inhibited with increasing polyphosphates concentration and decreasing the incubation temperature. Minimal inhibitory concentration of polyphosphates to the growth of strain was about 12,000 ppm. It was observed, using both scanning electron microscopy(SEM) and transmission electron microscopy(TEM), that 0.9% polyphosphates treatment was resulted in the destruction of cell wall and outflow of cell ingredients. The antimicrobial effects of polyphosphates were more effective than those of dehydroacetate and potassium sorbate at 13℃ and 4℃. The growth rate of the strain in beef was significantly inhibited by the treatment of 0.9% polyphosphates and storaged at cooling temperature.

The antifungal effects of polyphosphates on the growth and T-2 toxin production of Fusarium sporotrichioides M-1-1 were investigated. The growth of the strain was significantly inhibited in the potatoes dextrose agar medium treated with 1.5% polyphosphates or more. When we checked T-2 toxin by the indirect competitive ELISA, the strain produced 11.25 ug/ml and 10.90 g/ml levels of T-2 toxin in rice and corn containing 50% moisture contents, respectively. However, T-2 toxin was little detected in rice medium and corn medium with 1.5% polyphosphates addition for short(14 days) and prolonged incubation time(45 days). We also observed the destruction of cell wall and outflow of cell ingredients with 1% polyphosphates treatment to the strain. Therefore, moisture and polyphosphates greatly effected on the growth and T-2 toxin production of the strain.