• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1697-1701
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• 2015

The anticancer and anti-inflammatory activities of probiotic Lactococcus lactis NK34 were demonstrated. Treatment of cancer cells such as SK-MES-1, DLD-1, HT-29, LoVo, AGS, and MCF-7 cells with 10⁶ CFU/well of L. lactis NK34 resulted in strong inhibition of proliferation (>77% cytotoxicity, p < 0.05). The anti-inflammatory activity of L. lactis NK34 was also demonstrated in lipopolysaccharide-induced RAW 264.7 cells, where the production of nitric oxide and proinflammatory cytokines (tumor necrosis factor-α, interleukin-18, and cyclooxygenase-2) was reduced. These results suggest that L. lactis NK34 could be used as a probiotic microorganism to inhibit the proliferation of cancer cells and production of proinflammatory cytokines.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.457-462
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• 2008

Lactococcus lactis NK34, isolated from jeotgal (Korean traditional fermented fish), produces bacteriocin against bovine mastitis pathogens such as Staphylococcus aureus 7, S. aureus 8, Staphylococcus chromogenes 10, S. chromogenes 19, Staphylococcus hominis 9, Streptococcus uberis E290, Enterococcus faecium E372, Streptococcus agalactiae ATCC 13813, Pseudonocardia autotrophia KCTC 9455, and Staphylococcus simulans 78. Lacticin NK34 was inactivated by protease XIV but not by protease IX, protease XIII, proteinase K, $\acute{a}$-chymotrypsin, trypsin, and pepsin. Also, lacticin NK34 was stable over a pH range of 2 to 9 for 4 hr and withstood exposure to temperatures of 30-$100^{\circ}C$ for 30 min. Lacticin NK34 showed bactericidal effects against S. simulans 78. This bacteriocin was purified using ammonium sulfate precipitation, ion exchange chromatography, ultrafiltration, and hydrophobic chromatography. Tricin-SDS-PAGE of purified bacteriocin gave the same molecular weight (3.5 kDa) as nisin. The gene encoding this bacteriocin was amplified by PCR using nisin gene-specific primers. It showed similar sequences to this nisin Z gene. These results indicate that lacticin NK34 is a nisin-like bacteriocin, and could be used as an antimicrobial alternative for livestock.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.843-847
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• 2007

Strain NK34 was characterized for probiotic use. Strain NK34 was named Lactococcus lactis NK34 based on API 50 CHL kit results and 16S rDNA sequencing. L. lactis NK34 was highly resistant to artificial gastric juice (pH 2.5) and artificial bile acid. Based on results from the API ZYM kit, 4 enzymes were produced. L. lactis NK34 was resistant to all antibiotics tested except for $10\;{\mu}g/mL$ roxithromycin and $10\;{\mu}g/mL$ erythromycin. The cholesterol-lowering effect of L. lactis NK34 was about 46.9%. Concentrations of interleukin $(IL)-1{\alpha}$ in the $20{\times}$ concentrated supernatant of L. lactis NK34 was about 361 pg/mL. L. lactis NK34 was also found to inhibit the growth of colon cancer cells due to MNNG-induced DNA damage. These results demonstrate the potential of L. lactis NK34 as a health-promoting probiotic.