• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.483-487
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• 2016

The triglyceride-lowering effect of probiotics Lactobacillus plantarum KY1032 and Lactobacillus curvatus HY7601 were investigated. Male SD Wistar rats were randomly divided into three groups and fed high-fat diet (HFD), HFD and probiotics (5 × 10⁹ CFU/day of L. plantarum KY1032 and 5 × 10⁹ CFU/day of L. curvatus HY7601), or normal diet for 6 weeks. Probiotic treatment significantly lowered the elevated plasma triglyceride and increased plasma free fatty acid, glycerol, and plasma apolipoprotein A-V (ApoA-V) levels. The probiotic-treated group showed elevated hepatic mRNA expression of PPARα, bile acid receptor (FXR), and ApoA-V. These results demonstrate that L. plantarum KY1032 and L. curvatus HY7601 lower triglycerides in hypertriglyceridemic rats by upregulating ApoA-V, PPARα, and FXR.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.305-315
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• 1994

Nineteen strains of bacteriocin-producing lactic acid bacteria were isolated from 432 Kimchi samples, and identified by the comprehensive biochemical and morphological tests verifying their cellular fatty acid composition. Using partially purified bacteriocins from these isolates, their inhibitory activities against other lactic acid bacteria and some pathogens, and sensitivity to enzyme and heat treatments were tested. The isolates were identified as Lactobacillus plantarum (2 strains), L curvatus (2 starins), L brevis (2 strains), Enterococcus faecium (6 strains), Leuconostoc mesenteroides subsp. mesenteroides (1 strain) and Lactobacillus sp. (6 strains). The bacteriocins produced by E. faecium strains provided the broadest spectrum of inhibition, affecting against other Gram-positive bacteria including lactic acid bacteria and health-threatening bacteria such as Clostridium perfringens and Listeria monocytogenes. The bacteriocins of Lactobacillus sp., L plantarum and L brevis strains were capable of inhibiting many strains of the lactic acid bacteria, whereas those of L curvatus and L mesenteroides subsp. mesenteroides strains were only inhibitory to a few strains. Generally, the inhibitory activities of both E. faecium and Lactobacillus sp. strains were greater than those of other producer strains. The bacteriocins from the isolates were sensitive to several proteolytic enzymes, and those of L curvatus and L mesenteroides subsp. mesenteroides were also sensitive to lipase and $\alpha$-amylase as well as to proteolytic enzymes. The bacteriocins from the strains of Lactobacillus sp. and a strain of L. brevis were resistant to autoclaving.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.588-594
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• 1998

Lactic acid bacteria were isolated from Kimchi and screened for bacteriocin production. Strain SE1, identified as Lactobacillus curvatus sp., showed the strongest inhibitory activity against Lactobacillus delbrueckii subsp. delbrueckii. The bacteriocin was inactivated by amyloglucosidase, trypsin, or protease K treatment. However, it maintained its activity under heat treatment at $100^{\circ}C$ for 60 min. The production of the bacteriocin had a growth-related mode and decreased around the early-stationary phase. The optimum temperature for the growth of L. curvatus SE1 was $37^{\circ}C$; however, the optimum temperature for bacteriocin production was $30^{\circ}C$. The bacteriocin activity was decreased by treatment with methanol, butanol, acetone, or chloroform, however, it was not affected by treatment with ethanol, iso-propanol, or cyclohexane. The inhibitory activity of bacteriocin was stable over a wide range of pHs (2 to 11). The bacteriocin from L. curvatus SE1 killed the indicator strain by a bactericidal mode of action. The bacteriocin from L. curvatus SE1 was partially purified by ethanol precipitation and ion exchange chromatography. SDS-polyacrylamide gel electrophoresis was used to determine the molecular weight of the bacteriocin by the bacteriocin activity test. The apparent molecular mass of the bacteriocin produced by L. curvatus SE1 was about 14 kDa.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2148-2158
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• 2016

To investigate the effects of Lactobacillus curvatus and Leuconostoc mesenteroides on suan cai (pickled Chinese cabbage) fermentation, L. curvatus and/or Ln. mesenteroides were inoculated into suan cai. Physicochemical indexes were measured, and the microbial dynamics during the fermentation were analyzed by Illumina MiSeq sequencing and quantitative polymerase chain reaction (qPCR). The results showed that inoculation with lactic acid bacteria (LAB) lowered the pH of the fermentation system more rapidly. The decrease in water-soluble carbohydrates in the inoculated treatments occurred more rapidly than in the control. The LAB counts in the control were lower than in other inoculated treatments during the first 12 days of fermentation. According to the Illumina MiSeq sequencing analyses, Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, Cyanobacteria, Fusobacteria, and Verrucomicrobia were present in the fermentations, along with other unclassified bacteria. Generally, Firmicutes was predominant during the fermentation in all treatments. At the genus level, 16 genera were detected. The relative abundance of Lactobacillus in all inoculated treatments was higher than in the control. The relative abundance of Lactobacillus in the treatments containing L. curvatus was higher than in the Ln. mesenteroides-only treatment. The relative abundance of Leuconostoc in the Ln. mesenteroides-containing treatments increased continuously throughout the fermentation. Leuconostoc was highest in the Ln. mesenteroides-only treatment. According to the qPCR results, L. curvatus and/or Ln. mesenteroides inoculations could effectively inhabit the fermentation system. L. curvatus dominated the fermentation in the inoculated treatments.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1009-1016
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• 2014

This study investigated the probiotic and functional characteristics of Mukeunji starter, Lactobacillus curvatus ML17, isolated from Mukeunji. Lb. curvatus ML17 was confirmed as a safe microorganism due to its non-hemolytic activity and non-production of harmful ${\beta}$-glucuronidase and ${\beta}$-glucosidase. Tolerance to artificial gastric and bile juice of Lb. curvatus ML17 was investigated. After incubation in artificial gastric and bile juice, the number of surviving cells was $1.38{\times}10^8$ CFU/mL. According to the results of adhesion assay, this strain also exhibited good adhesion to Caco-2 cells. Lb. curvatus ML17 showed good antimicrobial activity against food borne pathogens, especially Micrococcus luteus, Bacillus cereus, Salmonella enterica subsp. enterica, and Pseudomonas aeruginosa. Cell-free extract of Lb. curvatus ML17 exhibited high levels of DPPH scavenging capacity and inhibitory effects on growth of AGS human gastric adenocarcinoma cells and HT-29 human colon carcinoma cells. These results suggest that Lb. curvatus ML17 has potential for application in functional foods.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.238-242
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• 2009

Pediococci selective medium (PSM) supplemented with ampicillin (A) reported as valid for the detection and enumeration of pediococci included in foods and animal feed was evaluated for the selective detection of the genus Pediococcus in kimchi. PSM is based on the complex basal medium MRS supplemented with cysteine hydrochloride, vancomycin, novobiocin, and nystatin. In the medium evaluation with known species, the growth inhibition of leuconostocs, Pediococcus pentosaceus, Lactobacillus casei, Lactobacillus curvatus, Oenococcus oeni, and Streptococcus thermophilus was not confirmed. In the application of kimchi samples on the selective medium, leuconostocs, P. pentosaceus, Weissella koreensis, Lb. curvatus, Lactobacillus brevis, and Lactobacillus sakei were detected. PSM+A was proved to be not applicable for the detection of pediococci in kimchi.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.544-549
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• 1994

Lactobacilli proliferating in fermented sausages of the specific ripening conditions were isolated from fermented sausages, manufactured in the absence of an added starter, during ripening under controlled temperature-humidity conditions. Based on morphological, physiological and bio- chemical characteristics and carbohydrate fermentation of isolated strains, three strains of isolates were identified as Lactobacillus curvatus, two strains as Lactobacillus sake. Optimal temperature and pH for growth of isolated strains were 30$\circ$C and pH 6.0~7.0, respectively. These strains were salt tolerant, multiplying in the presense of 6~8% NaCl.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.4
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• pp.585-594
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• 2018

Objective: This study was to determine the bacterial diversity and monitor the community dynamic changes during storage of vacuum-packaged sliced raw beef as affected by Lactobacillus sakei and Lactobacillus curvatus. Methods: L. sakei and L. curvatus were separately incubated in vacuumed-packaged raw beef as bio-protective cultures to inhibit the naturally contaminating microbial load. Dynamic changes of the microbial diversity of inoculated or non-inoculated (control) samples were monitored at $4^{\circ}C$ for 0 to 38 days, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Results: The DGGE profiles of DNA directly extracted from non-inoculated control samples highlighted the order of appearance of spoilage bacteria during storage, showing that Enterbacteriaceae and Pseudomonas fragi emerged early, then Brochothrix thermosphacta shared the dominant position, and finally, Pseudomonas putida showed up became predominant. Compared with control, the inoculation of either L. sakei or L. curvatus significantly lowered the complexity of microbial diversity and inhibited the growth of spoilage bacteria (p<0.05). Interestingly, we also found that the dominant position of L. curvatus was replaced by indigenous L. sakei after 13 d for L. curvatus-inoculated samples. Plate counts on selective agars further showed that inoculation with L. sakei or L. curvatus obviously reduced the viable counts of Enterbacteraceae, Pseudomonas spp. and B. thermosphacta during later storage (p<0.05), with L. sakei exerting greater inhibitory effect. Inoculation with both bio-protective cultures also significantly decreased the total volatile basic nitrogen values of stored samples (p<0.05). Conclusion: Taken together, the results proved the benefits of inoculation with lactic acid bacteria especially L. sakei as a potential way to inhibit growth of spoilage-related bacteria and improve the shelf life of vacuum-packaged raw beef.

• Journal of Microbiology and Biotechnology
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• v.32 no.3
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• pp.348-354
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• 2022

Recent studies have shown that probiotics have health-promoting effects, particularly intestinal immune modulation. In this study, we focused on the immunomodulatory properties of Latilactobacillus curvatus BYB3, formerly called Lactobacillus curvatus, isolated from kimchi. In a mouse model of 14-day dextran sulfate sodium (DSS)-induced colitis, treatment with L. curvatus BYB3 significantly decreased the disease activity index, colon length, and weight loss. Moreover, histological analyses showed that L. curvatus BYB3 protected the structural integrity of the intestinal epithelial layer and mucin-secreting goblet cells from DSS-induced damage, with only slight infiltration by immune cells. To evaluate the molecular mechanisms underlying L. curvatus BYB3-driven inhibition of interleukin 6 production, possible in vivo anti-inflammatory effects of L. curvatus BYB3 were examined in the same mouse model. In addition, significantly lower levels of IL-6 and tumor necrosis factor receptor 1 upregulation were seen in the DSS+BYB3 group (compared to that in the DSS group). These results indicate that L. curvatus BYB3 exhibits health-promoting effects via immune modulation; and therefore, it can be used to treat various inflammatory diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1872-1877
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• 2013

Lactic acid bacteria were selected on the basis of lactic acid producing ability from kimchi, a traditional Korean fermented food. Among the initial screening of over 150 strains selected from the sample, 27 strains were selected as lactic acid producing bacteria, and 4 strains were finally selected based on their ability to produce relatively high levels of lactic acid. The four strains were identified as Lactobacillus (L.) plantarum Gk04, Pediococcus pentosaceus Gk07, L. brevis Gk35 and L. curvatus Gk36 by the conventional morphological, cultural, physiological and biochemical characteristics, as well as by 16S rRNA sequence analysis. Among the identified lactic acid bacteria, L. curvatus Gk36 was used for soymilk fermentation. The viable cell counts and acidity values measured for the L. curvatus Gk36 were comparable to the commmercial L. acidopillus. Thus, the L. curvatus Gk36 is a potential probiotic strain to prepare fermented soy products, such as kephir, yogurt, tempeh and soy sauce.