• Mycobiology
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• v.33 no.4
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• pp.210-214
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• 2005

More than 120 isolates of lactic acid bacteria obtained from Kimchi was screened for antifungal activity against Aspergillus fumigatus. Approximately 10% of the isolates showed inhibitory activity and only 4.16% (five isolates) exhibited strong activity against the indicator fungus A. fumigatus. The five isolates showed a wide rang of antifungal activity against A. flavus, Fusarium moniliforme, Penicillium commune, and Rhizopus oryzae. They were identified by 16S rDNA sequencing as Lactobacillus cruvatus, L. lactis subsp. lactis, L. casei, L. pentosus, and L. sakei. The effect of Lactobacillus on mycelial growth and fungal biomass as well as its ability to produce toxic compounds were determined. The results indicate that the three species, Lactobacillus casei, L. lactis subsp. lactis, and L. pentosus, are active against A. fumigatus.

• Microbiology and Biotechnology Letters
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• v.49 no.1
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• pp.1-8
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• 2021

Human breast milk is a potential source of bacteria for the development of the intestinal microbiota of infants. Several species within the genera Lactobacillus and Bifidobacterium were demonstrated to shape the gut microbiota of infants. In this study, the bacterial diversity was investigated in the breast milk and feces of a mother-infant pair, and probiotic candidates were identified. Importantly, the novel L. gasseri EJL and B. breve JTL strains were isolated from breast milk and infant feces samples, respectively; their completed genome was resolved using de novo sequencing. In addition, the bacterial composition in the infant's feces at 1 week revealed the prevalence of Bifidobacterium and Streptococcus; a higher diversity was observed after 3 weeks. In particular, the abundance of Akkermansia was sharply increased at 7 weeks, further increasing thereafter, up to 15 weeks. Our results suggest that human breast milk and infant's feces are a source of probiotic candidates.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.473-482
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• 2003

In vivo protective and in vitro inhibitory activities of Lactobacillus casei YIT 9018. against typical enteritis causing Salmonella enteritidis KU101 and IgA level after challenge have been determined. In order to identify the strains of lactobacilli the sequences of 16S-23S rRNA intergenic spacer region were determined. All the test strains of Lactobacillus spp. inhibited Salmonella enteritidis, the intensity varied depending upon the species of lactobacilli. Effects on the survival rate of the mouse after challenge with Salmonella enteritidis KU101 on feeding Lactobacillus spp. have shown the highest survival rate in L. helveticus CU 631 followed by L. casei YIT 9018 and L. johnsonii C-4 and the lowest in control mice. The higher level of total Ig A concentration in the intestinal fluid of lactobacilli fed mice than control mice was observed. The sequences of 16S-23S rRNA intergenic spacer region of seven strains of Lactobacillus casei could be utilized as a strain identification, those sequences showed some degree of difference in homology.

• KSBB Journal
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• v.24 no.2
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• pp.182-188
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• 2009

Lactobacillus spp., primary members of probiotics, have significant benefits for health and well-being of human. In this study Lactobacillus strains representing six species (L. paracasei KLB58, L. fermentum MS79 and KLB282, L. plantarum KLB213, L. gasseri KLB238, and L. reuteri KLB270) isolated from Korean adults were electrotransformed with plasmid pNCKH104. To determine optimal electrotransformation conditions, various conditions including cell wall weakening agent, electroporation buffer, electric field strength and time constant were tested for each strain. Overall, high transformation efficiency of approximately 2.5 ${\times}$ $10^3$ ${\sim}$ 5.5 ${\times}$ $10^4$ CFU/${\mu}g$ DNA was obtained where conditions of 0.5 M sucrose electroporation buffer, 1.8 kV pulse voltage and 5 ms time constant were applied. The common conditions developed in this study will make transformation of various Lactobacillus spp. easier than previous procedures.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.1
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• pp.9-14
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• 2018

Bacterial species, Bacillus amyloliquefaciens and Lactobacillus species (L. sp.5-1), are known to inhibit the growth of pathogenic bacteria and fungi. Metarhizium anisopliae is a pathogenic fungal species which causes fatal damage to P. brevitarsis populations. Therefore, we investigated the inhibitory effect of B. amyloliquefaciens and L. sp. 5-1 on M. anisopliae induced fatality rates in P. brevitarsis. Samples of M. anisopliae-infected sawdust were treated with strain B. amyloliquefaciens KACC10116, strain L. sp. 5-1 KACC19351, and a combination of the two. P. brevitarsis were fed treated sawdust samples, and their subsequent fatality rate was monitored. The fatality rate fell below 1.5% after 10 days and decreased by approximately 40% after 15 days. On average, the fatality rate decreased by 20%, compared to the control. The difference in the decrease in fatality rate between B. amyloliquefaciens treatment and L. sp. 5-1 treatment was not significant. Results indicate that both strains exhibit high anti-fungal activity, which may be useful in environmental purification efforts. These strains may be used for effective prevention of fungal infection in P. brevitarsis.

• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.93-98
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• 2023

Nuruk is a starter culture of Korea manufactured by spontaneous fermentation of grains. We isolated bacteria of the genera Bacillus and Staphylococcus, and lactic acid bacteria (LAB) from eight commercial nuruk samples collected from four districts of Korea using selective agar media and identified them based current taxonomic standards. Bacillus was detected in all samples, but Staphylococcus or LAB were not detected in three samples. In seven samples, except one sample scored the highest cell number of LAB, Bacillus and Staphylococcus were counted as the highest and the lowest numbers, respectively. Six species of Bacillus were identified, and B. subtilis, B. velezensis, and B. licheniformis were predominant species. Nine species of coagulase-negative Staphylococcus were identified, and the predominance of S. pseudoxylosus and S. saprophyticus was confirmed. Ten species of LAB including Enterococcus, Lactobacillus and close relatives, Pediococcus, and Weissella were identified. P. pentosaceus was identified as the predominant species.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.479-491
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• 2015

Lactobacillus species have been shown to enhance intestinal epithelial barrier function, modulate host immune responses, and suppress the growth of pathogenic bacteria, yeasts, molds, and viruses. Thus, lactobacilli have been used as probiotics for treating various diseases, including intestinal disorders, and as biological preservatives in the food and agricultural industries. However, the molecular mechanisms used by lactobacilli to suppress pathogenic bacterial infections have been poorly characterized. We previously isolated Lactobacillus plantarum JSA22 from buckwheat sokseongjang, a traditional Korean fermented soybean food, which possessed high enzymatic, fibrinolytic, and broad-spectrum antimicrobial activity against foodborne pathogens. In this study, we investigated the effects of L. plantarum JSA22 on the growth of S. Typhimurium and S. Typhimurium-induced cytotoxicity by stimulating the host immune response in intestinal epithelial cells. The results showed that coincubation of S. Typhimurium and L. plantarum JSA22 with intestinal epithelial cells suppressed S. Typhimurium infection, S. Typhimurium-induced NF-κB activation, and IL-8 production, and lowered the phosphorylation of both Akt and p38. These data indicated that L. plantarum JSA22 has probiotic properties, and can inhibit S. Typhimurium infection of intestinal epithelial cells. Our findings can be used to develop therapeutic and prophylactic agents against pathogenic bacteria.

• KSBB Journal
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• v.26 no.5
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• pp.374-380
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• 2011

Earlier in Korea Kimchi was made in every family and every province has own taste and specialties. These days almost of the Kimchis are manufactured. We collected variable Kimchis, which were made for private use and isolated microorganisms. Some interesting micobial cells were identified and studied for its application as food and drinks. One of them was identified as Lactobacillus sakei KJ123. This strain is known as producing interesting aromatic components during Sakei fermentation like Kimchi in variable conditions. We tried to develop a health beverage with fermentation process. The Cucurbita maxima has been known as a traditional healthy food and variable positive effects on the human body were already reported. In this study we tried to develop a production process for a healthy fermented drink on this substrate with strains originated from Kimchi. Many kinds of lacctobacilli species existed in the fermented food cannot survive in the acidic conditions like human stomach. So we selected resisting strains in this conditions. The survival rate of Lactobacillus sakei cells in the artificial gastric juice and bile acid and other physiological characteristics at the variable conditions have been tested. After fermentation process some sensory tests on the product with panels were tried.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.109-114
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• 2014

Objectives: Recurrent caries was partly ascribed to lack of antibacterial properties in composite resin. Silver and zinc nanoparticles are considered to be broad-spectrum antibacterial agents. The aim of the present study was to evaluate the antibacterial properties of composite resins containing 1% silver and zinc-oxide nanoparticles on Streptococcus mutans and Lactobacillus. Materials and Methods: Ninety discoid tablets containing 0%, 1% nano-silver and 1% nano zinc-oxide particles were prepared from flowable composite resin (n = 30). The antibacterial properties of composite resin discs were evaluated by direct contact test. Diluted solutions of Streptococcus mutans (PTCC 1683) and Lactobacillus (PTCC 1643) were prepared. 0.01 mL of each bacterial species was separately placed on the discs. The discs were transferred to liquid culture media and were incubated at $37^{\circ}C$ for 8 hr. 0.01 mL of each solution was cultured on blood agar and the colonies were counted. Data was analyzed with Kruskall-Wallis and Mann-Whitney U tests. Results: Composites containing nano zinc-oxide particles or silver nanoparticles exhibited higher antibacterial activity against Streptococcus mutans and Lactobacillus compared to the control group (p < 0.05). The effect of zinc-oxide on Streptococcus mutans was significantly higher than that of silver (p < 0.05). There were no significant differences in the antibacterial activity against Lactobacillus between composites containing silver nanoparticles and those containing zinc-oxide nanoparticles. Conclusions: Composite resins containing silver or zinc-oxide nanoparticles exhibited antibacterial activity against Streptococcus mutans and Lactobacillus.

• Journal of Dairy Science and Biotechnology
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• v.22 no.2
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• pp.107-112
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• 2004

Studies on the resistance of Lactobacillus ssp., Bifidobacterium spp. and Bacillus coagulans to hydrogen peroxide were conducted by determination of the viable cells after the test cells in 2mM hydrogen peroxide solution for a predetermined time; L. acidophilus CU4111 and L. casei CU4114 were most resistant to the hydrogen peroxide among the fifteen test lactobacilli strains, whereas L. brevis Cu4206 was the strain which was the most susceptible to hydrogen peroxide. Bifidobacterium longum Cu4131 was one of the resistant strains. A prominant tendency found out that Bacillus coagulans possessed a strong resistance to hydrogen peroxide. The results of level of hydrogen peroxide determination in the cell extracts showed all the test strains contained hydrogen peroxide in the cytoplasm, the amount varied depending on the strain and species of lactic acid bacteria. Bifidobacterium bifidum CU 4134 and L. casei CU 4114 were potent hydrogen peroxide producer strain.