• Microbiology and Biotechnology Letters
• /
• v.43 no.4
• /
• pp.401-404
• /
• 2015

Bacillus coagulans has been considered to be a prominent candidate for probiotics as well as a thermotolerant biomaterial producer. However, the species has not attracted the attention of Korean researchers, nor has it been commercialized in Korea. Therefore, isolates for functional studies are not readily available. To secure B. coagulans resources for future applications, we developed a rapid isolation method for the species from rice straw. Introduction of the enrichment culture at $50^{\circ}C$, the selection of acid producers with $CaCO_3$ supplemented medium, and the elimination of enterococci by selective medium, rendered the successful and rapid isolation of B. coagulans strains.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.6
• /
• pp.1148-1161
• /
• 2016

Lactobacilli are universally recognized as probiotics that are widely used in the adjuvant treatment of inflammatory diseases, such as vaginitis and enteritis. With the overuse of antibiotics in recent years, the lactobacilli in the human body are killed, which could disrupt the microecological balance in the human body and affect health adversely. In this work, cephalosporin-resistant Lactobacillus casei RL20 was obtained successfully from the feces of healthy volunteers, which possessed a stable genetic set. However, the shortage of lactic acid (72.0 g/l at 48 h) by fermentation did not meet the requirement for its use in medicine. To increase the production of lactic acid, the functional genes pfk and glk were introduced into the wild strain. A yield of 144.2 g/l lactic acid was obtained in the transgenic L. casei RL20-2 after fermentation for 48 h in 1 L of basic fermentation medium with an initial glucose concentration of 100 g/l and increasing antibacterial activity. These data suggested that L. casei RL20-2 that exhibited a high yield of lactic acid may be a potential probiotic to inhibit the spread of bacterial infectious diseases and may be used for vaginitis therapy.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.7
• /
• pp.1266-1273
• /
• 2008

Lactic acid bacteria (LAB) with antimicrobial activity and high exopolysaccharide (EPS) production ability isolated from sourdough were studied for their fermentation characteristics as potential new starter cultures. The values of pH, titratable acidity, and viable cell counts were $4.06{\pm}0.009-4.50{\pm}0.015,\;0.787{\pm}0.020%-1.172{\pm}0.018%,\;and\;8.78{\pm}0.08-8.98{\pm}0.06$ log CFU/ml, respectively. In order to select probiotics with a high survival rate in the gut, isolates were tested to assess resistance against the artificial gastric acid and bile juice. Viable LAB counts were significantly (p<0.05) affected by the acidity. At pH 2.0, the total declines in the initial bacterial counts were 4.52$\pm$0.07 log for S. thermophilus St-Body-1, >7.98$\pm$0.03 log for E. flavescens DU-10, >7.95$\pm$0.05 log for E. faecium DU-12, and 3.15$\pm$0.06 log for L. amylovorus DU-21. Among the strains, L. amylovorus DU-21 was the only strain that had bile tolerance under simulated gastrointestinal conditions. In order to improve EPS production by L. amylovorus DU-21, the influence of carbon source was studied. When glucose was used as a carbon source, EPS production dramatically increased to 17.19$\pm$0.28 g/l (p<0.05). The maximum cell growth (10.012$\pm$>0.012 log CFU/ml) and EPS production (18.71$\pm$0.19 g/l) were achieved when 15 g/l of glucose was employed as the carbon source.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.7
• /
• pp.1278-1285
• /
• 2008

The intestinal epithelial cell (IEC) layer of the intestinal tract makes direct contact with a number of microbiota communities, including bacteria known to have deleterious health effects. IECs possess innate protective strategies against pathogenic challenge, which primarily involve the formation of a physicochemical barrier. Intestinal tract mucins are principal components of the mucus layer on epithelial surfaces, and perform a protective function against microbial damage. However, little is currently known regarding the interactions between probiotics/pathogens and epithelial cell mucins. The principal objective of this study was to determine the effects of Lactobacillus on the upregulation of MUC2 mucin and the subsequent inhibition of E. coli O157:H7 attachment to epithelial cells. In the current study, the attachment of E. coli O157:H7 to HT-29 intestinal epithelial cells was inhibited significantly by L. acidophilus A4 and its cell extracts. It is also important to note that the expression of MUC2 mucin was increased as the result of the addition of L. acidophilus A4 cell extracts (10.0 mg/ml), which also induced a significant reduction in the degree to which E. coli O157:H7 attached to epithelial cells. In addition, the mRNA levels of IL-8, IL-1$\beta$, and TNF-$\alpha$ in HT-29 cells were significantly induced by treatment with L. acidophilus A4 extracts. These results indicate that MUC2 mucin and cytokines are important regulatory factors in the immune systems of the gut, and that selected lactobacilli may be able to induce the upregulation of MUC2 mucin and specific cytokines, thereby inhibiting the attachment of E. coli O157:H7.

• Journal of Dairy Science and Biotechnology
• /
• v.34 no.3
• /
• pp.145-155
• /
• 2016

Cow's milk and dairy products are elements of the human diet that could play an important role in improving human health. The macronutrients and micronutrients found in milk could supply the nutrients required to maintain human health. Among them, milk-derived bioactive peptides have been identified as potential ingredients found in health promoting functional foods. These bioactive peptides target diet-related chronic diseases, particularly non-communicable ones such as cardiovascular disease, diabetes and obesity. Additionally probiotics such as lactic acid bacteria (LAB) are can be considered live microorganisms that confer health benefits for the host-, when administered in adequate amounts. Further, the calcium, vitamin D, and protein content of milk and dairy products could play a role in proving bone health. The effect of milk and calcium on bone mineral density could prevent against fracture, osteoporosis and rickets. Furthermore, milk and dairy products also contain which factors that, which protect against dental caries (anti-cariogenic properties). This paper reviews the various nutritional functions of milk and dairy products in improving human health.

• Food Science of Animal Resources
• /
• v.33 no.1
• /
• pp.75-82
• /
• 2013

This study aimed to isolate lactic acid bacteria (LAB) from Kimchi and to identify suitable probiotic strain for application in fermented dairy product as a commercial starter culture. A total of 106 (LAB) strains were isolated from Kimchi collected from different regions in Korea and their phenotypic characteristics were assayed. Four isolates from MRS agar plates were selected and designated as DKL109, DKL119, DKL121 and DKL128. They were identified first by API 50 CHL kit and then 16S rRNA gene sequencing. DKL121 and DKL128 were identified as Lactobacillus paracasei and Lactobacillus casei, respectively. Other two isolates (DKL109 and DKL119) were identified as Lactobacillus plantarum. To estimate their applicability in dairy products, the characteristics including acid and bile tolerance, cold shock induced cryotolerance and enzymatic activities were determined. There was wide variation in ability of strains to acid tolerance, but no significant differences in bile tolerance, cold shock induced cryotolerance within selected strains. DKL119 and DKL121 showed the highest resistance to acid and bile and the highest ${\beta}$-galactosidase activity, respectively. When these two strains were used for yogurt preparation as a single starter culture, their viable cell counts reached to $1.0{\times}10^9CFU/mL$. Lactobacillus plantarum DKL119 showed faster acid development than commercial starter culture. Also storage trials at $10^{\circ}C$ showed that the viability of these strains was retained over 15 d. With these results, it was indicated that probiotics isolated from Kimchi can be used in yogurt manufacturing as a starter culture.

• Journal of Radiation Industry
• /
• v.6 no.2
• /
• pp.177-180
• /
• 2012

The acid and bile tolerance changes of 5 different lactic acid bacteria (LAB; Lactobacillus paracasei, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus debruekii) with gamma irradiation were evaluated. The abilities of LAB to survive in the acidic conditions at the stomach and the bile acidic conditions at the beginning of the small intestine are the key functions for applying LAB to probiotics. In the results, all of LAB survived more than 50% after incubation in PBS (pH 2.5) for 2 hr, which indicated more than half of LAB are possible to pass through the stomach. However, gamma irradiation decreased the acid tolerances of LAB. The bile tolerances of all bacteria except Lactobacillus acidophilus were observed to survive at a 3% oxgall concentration in MRS, and 1 kGy of gamma irradiation to LAB did not affect any bile tolerances changes. But gamma irradiated Lactobacillus casei and Lactobacillus casei (3 kGy) showed decreasing survival rate with oxgall added MAS agar. In conclusion, gamma irradiation should be applied to yogurt or fermented foods with care because LAB could be changes their properties on acid and bile tolerances.

• Journal of agriculture & life science
• /
• v.46 no.5
• /
• pp.83-90
• /
• 2012

A study was investigated the effects of the probiotic mixture (PM) contained Lactobacillus plantarum (L. plantarum) SY-99 $2.4{\times}10^9CFU/kg$ and Bacillus subtilis (B. subtilis) SJ-61 $2.2{\times}10^9CFU/kg$ on growth performance and fecal microflora counts of broiler chickens. Referred to the previous studies, a total of 160 one-day-old male broiler chicken (Ross 308) were randomly assigned to four experimental groups, which were a basal diet alone (control) and supplemented with PM 0.1 g/kg feed (T1), PM 0.2 g/kg feed (T2), and PM 0.4 g/kg feed (T3). After 28 days of administration, the average daily feed intake of T1 and T3 was significantly different compared to that of control (p<0.05). In addition, the feed conversion ratio of T2 and T3 was significantly improved compared to that of control (p<0.05). On the 28th day after administration, all treatment groups were significantly increased fecal lactic acid bacteria (LAB) counts and decreased fecal Enterobacteriaceae (ENT) counts compared to T1 (p<0.05). The results of this study indicated that the combination of L. plantarum and B. subtilis strains in the range of 0.2-0.4 g/kg feed could be used for the improvement of growth performance and fecal microflora in broiler chickens.

• Journal of Korean Medicine for Obesity Research
• /
• v.13 no.1
• /
• pp.24-32
• /
• 2013

Objectives: The aim of this study is to investigate anti-imflammatory and protective effect for intestinal epithelial cells with Atractylodes macrocephae (AM), a traditional Korean Herbal medicine and fermented Atractylodes macrocephae (FAM) with Lactobacillus plantarum. Methods: HCT-116 and Raw 264.7 cells were used in this study. Using NO assay, we measured lipopolysaccharide (LPS)-induced anti-inflammatory effect. We measured permeability of intestinal epithelial cells with transepithelial electrical resistance and horseradish peroxide flux assay. Water soluble tetrazolium salt assay was used to see cell proliferation. All the results were presented in mean and standard deviation. We used Student's t-test for analyzing significance of results. Results: In Raw 264.7 cells NO production decreased 22.4% with pre-treatment of AM and FAM, especially with FAM in high concentration. In HCT-116 cells LPS-induced intestinal permeability had a protective effect with both AM and FAM, which was also tend to be proportional to the concentration. Cell viability increased up to 135.52% after treatment of high concentration of FAM in HCT-116, while there was no significant change in Raw 264.7 cells with herb treatments. Conclusions: These results show evidence that AM, especially fermented ones, significantly reduced intestinal membrane permeability. They also had a protective effect as well as an anti-inflammation effect for HCT-116 and Raw 264.7 cells. This suggest that FAM may be a therapeutic agent for Leaky gut syndrome by reducing intestinal permeability.

• Molecules and Cells
• /
• v.42 no.11
• /
• pp.755-762
• /
• 2019

Despite decades of research into colorectal cancer (CRC), there is an ongoing need for treatments that are more effective and safer than those currently available. Lactic acid bacteria (LAB) show beneficial effects in the context of several diseases, including CRC, and are generally regarded as safe. Here, we isolated a Lactobacillus rhamnosus (LR)-derived therapeutic protein, p8, which suppressed CRC proliferation. We found that p8 translocated specifically to the cytosol of DLD-1 cells. Moreover, p8 down-regulated expression of Cyclin B1 and Cdk1, both of which are required for cell cycle progression. We confirmed that p8 exerted strong anti-proliferative activity in a mouse CRC xenograft model. Intraperitoneal injection of recombinant p8 (r-p8) led to a significant reduction (up to 59%) in tumor mass when compared with controls. In recent years, bacterial drug delivery systems (DDSs) have proven to be effective therapeutic agents for acute colitis. Therefore, we aimed to use such systems, particularly LAB, to generate the valuable therapeutic proteins to treat CRC. To this end, we developed a gene expression cassette capable of inducing secretion of large amounts of p8 protein from Pediococcus pentosaceus SL4 (PP). We then confirmed that this protein (PP-p8) exerted anti-proliferative activity in a mouse CRC xenograft model. Oral administration of PP-p8 DDS led to a marked reduction in tumor mass (up to 64%) compared with controls. The PP-p8 DDS using LAB described herein has advantages over other therapeutics; these advantages include improved safety (the protein is a probiotic), cost-free purification, and specific targeting of CRC cells.