• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.160-170
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• 2019

The lactic acid bacteria species Lactobacillus plantarum (L. plantarum) has been used extensively for vaccine delivery. Considering to the critical role of dendritic cells in stimulating host immune response, in this study, we constructed a novel CD11c-targeting L. plantarum strain with surface-displayed variable fragments of anti-CD11c, single-chain antibody (scFv-CD11c). The newly designed L. plantarum strain, named 409-aCD11c, could adhere and invade more efficiently to bone marrow-derived DCs (BMDCs) in vitro due to the specific interaction between scFv-CD11c and CD11c located on the surface of BMDCs. After incubation with BMDCs, the 409-aCD11c strain harboring a eukaryotic vector pValac-GFP could lead to more efficient expression of GFP compared with wild-type strains shown by flow cytometry analysis, indicating the enhanced translocation of pValac-GFP from L. plantarum to BMDCs. Similar results were also observed in an in vivo study, which showed that oral administration resulted in efficient expression of GFP in both Peyer's patches (PP) and mesenteric lymph nodes (MLNs) within 7 days after the last administration. In addition, the CD11c-targeting strain significantly promoted the differentiation and maturation of DCs, the differentiation of $IL-4^+$ and $IL-17A^+$ T helper (Th) cells in MLNs, as well as production of $B220^+$ $IgA^+$ B cells in the PP. In conclusion, this study developed a novel DC-targeting L. plantarum strain which could increase the ability to deliver eukaryotic expression plasmid to host cells, indicating a promising approach for vaccine study.

• Journal of Microbiology and Biotechnology
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• v.31 no.10
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• pp.1420-1429
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• 2021

The safety of the probiotic strain Q180, which exerts postprandial lipid-lowering effects, was bioinformatically and phenotypically evaluated. The genome of strain Q180 was completely sequenced, and single circular chromosome of 3,197,263 bp without any plasmid was generated. Phylogenetic and related analyses using16S rRNA gene and whole-genome sequences revealed that strain Q180 is a member of Lactiplantibacillus (Lp., formerly Lactobacillus) plantarum. Antimicrobial resistance (AMR) genes were bioinformatically analyzed using all Lp. plantarum genomes available in GenBank, which showed that AMR genes are present differently depending on Lp. plantarum strains. Bioinformatic analysis demonstrated that some mobile genetic elements such as prophages and insertion sequences were identified in the genome of strain Q180, but because they did not contain harmful genes such as AMR genes and virulence factor (VF)- and toxin-related genes, it was suggested that there is no transferability of harmful genes. The minimum inhibition concentrations of seven tested antibiotics suggested by the European Food Safety Authority guidelines were slightly lower than or equal to the microbiological cut-off values for Lp. plantarum. Strain Q180 did not show hemolytic and gelatinase activities and biogenic amine-producing ability. Taken together, this study demonstrated the safety of strain Q180 in terms of absence of AMR genes and VF- and toxin-related genes as a probiotic strain.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.681-698
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• 2022

The Nile tilapia Oreochromis niloticus, Atlantic salmon Salmo salar, rainbow trout Oncorhynchus mykiss, olive flounder Paralichthys olivaceus, common carp Cyprinus carpio, grass carp Ctenopharyngodon idella and rohu carp Labeo rohita are farmed commercially worldwide. Production of these important finfishes is rapidly expanding, and intensive culture practices can lead to stress in fish, often reducing resistance to infectious diseases. Antibiotics and other drugs are routinely used for the treatment of diseases and sometimes applied preventatively to combat microbial pathogens. This strategy is responsible for the emergence and spread of antimicrobial resistance, mass killing of environmental/beneficial bacteria, and residual effects in humans. As an alternative, the administration of probiotics has gained acceptance for disease control in aquaculture. Probiotics have been found to improve growth, feed utilization, immunological status, disease resistance, and to promote transcriptomic profiles and internal microbial balance of host organisms. The present review discusses the effects of single and multi-strain probiotics on growth, immunity, heamato-biochemical parameters, and disease resistance of the above-mentioned finfishes. The application and outcome of probiotics in the field or open pond system, gaps in existing knowledge, and issues worthy of further research are also highlighted.

• Food Science of Animal Resources
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• v.42 no.6
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• pp.996-1008
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• 2022

Lactic acid bacteria are representative probiotics that have beneficial effects on humans. Nineteen strains among the 167 single strains from kimchi was selected and their physiological features were investigated. The selection of a strain was based on strong enzyme (lipase, α-amylase, and α-glucosidase) inhibitory activities and anti-obesity effects in the adipocytes. For the final selection, the strain Lactiplantibacillus plantarum KC3 was tested for its potential as a starter. To assess its functionality, a freeze-dried culture of L. plantarum KC3 was administered to a diet-induced obese mouse model receiving a high-fat diet. The animal group administered with L. plantarum KC3 showed significant body weight loss during the 12-week feeding period compared to the high-fat control group. This study investigated the physiological characteristics of selected strain and evaluated its potential as an anti-obesity probiotic in mice.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.1027-1032
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• 2008

A study was conducted to evaluate the effects of dietary yeast derived ${\beta}$-glucan and single-strain probiotics on the growth performance and antibody response in broiler chicks. Six hundred and thirty 1-d-old male broiler chicks were divided into seven groups, placed into three pens per group (30 birds per pen) and fed one of seven non-medicated corn-SBM based experimental diets containing 0.025, 0.05 or 0.1% Saccharomyces cerevisiae ${\beta}$-glucan and 0.05, 0.1 or 0.2% Bacillus amyloliquefaciens (BA-pro, $1.3{\times}10^9/g$) or devoid of them for 5 wk. The body weight gains in groups fed diets containing 0.025 or 0.1% ${\beta}$-glucan, 0.1% or 0.2% BA-pro were significantly higher (p<0.05) than the control over 1-35 d. Feed conversion rates of groups fed ${\beta}$-glucan and BA-pro tended to be improved compared to the control group. There were no significant differences in the relative weights of liver, abdominal fat and breast muscle. No significant differences were observed in the activities of serum enzymes and concentrations of various cholesterol fractions. The antibody titers against Newcastle disease or infectious bronchitis virus in the chicks fed diets containing ${\beta}$-glucan and BA-pro were significantly higher (p<0.05) than in the control. The concentrations of cecal lactic acid bacteria in all groups fed BA-pro were significantly increased (p<0.05) compared to the control. These results indicated that dietary yeast derived ${\beta}$-glucan and BA-pro exerted growth-promoting and immune-enhancing effects in broiler chickens. In addition, BA-pro added to the diets modulated the profiles of cecal microflora, reflecting a potential to be beneficial microorganisms in chickens.

• Journal of Life Science
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• v.24 no.5
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• pp.549-557
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• 2014

This study examined the quality characteristics of fermented black garlic (BG) with probiotics. Nine strains of probiotics were tested in media containing 20% BG. Four of the strains grew well in the BG media: Lactobacillus rhamnosus, L. paracasei subsp. paracasei, L. casei, and L. plantarum. These four strains were used to make 10, 20, and 30% BG fermented product, respectively. The number of viable cells, pH, acidity, S-allyl cysteine (SAC) concentration, and nitric oxide (NO) and reactive nitrogen species (ROS) generation in Raw 264.7 macrophage cells were measured. L. plantarum showed the best growth of all the strains in the BG media. The pH of all the samples decreased during fermentation, and the acidity increased acidity. However, they did not differ significantly from the pH and acidity of the control. In all four strains, the SAC content did not differ before and after fermentation. However, the SAC content increased, depending on the BG concentration. NO production was inhibited in the L. rhamnosus inoculation strain compared to the other strains. ROS generation was also significantly inhibited in the L. plantarum inoculation strain compared to the other strains. The results show that the characteristics of BG fermentation products are determined by the fermentation strain. Therefore, fermentation products with particular characteristics can be produced using a single strain or mixed strains.

• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1419-1427
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• 2017

As probiotics play an important role in maintaining a healthy gut flora environment through antitoxin activity and inhibition of pathogen colonization, they have been of interest to the medical research community for quite some time now. Probiotic bacteria such as Lactobacillus plantarum, which can be found in fermented food, are of particular interest given their easy accessibility. We performed whole-genome sequencing and genomic analysis on a GB-LP1 strain of L. plantarum isolated from Korean traditional fermented food; this strain is well known for its functions in immune response, suppression of pathogen growth, and antitoxin effects. The complete genome sequence of GB-LP1 is a single chromosome of 3,040,388 bp with 2,899 predicted open reading frames. Genomic analysis of GB-LP1 revealed two CRISPR regions and genes showing accelerated evolution, which may have antibiotic and antitoxin functions. The aim of the present study was to predict strain specific-genomic characteristics and assess the potential of this new strain as lactic acid bacteria at the genomic level using in silico analysis. These results provide insight into the L. plantarum species as well as confirm the possibility of its utility as a candidate probiotic.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.684-692
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• 2016

Acute respiratory virus infectious diseases are a growing health problem, particularly among children and the elderly. Much effort has been made to develop probiotics that prevent influenza virus infections by enhancing innate immunity in the respiratory tract until vaccines are available. Lactobacillus plantarum GB-LP2, isolated from a traditional Korean fermented vegetable, has exhibited preventive effects on influenza virus infection in mice. To identify the molecular basis of this strain, we conducted a whole-genome assembly study. The single circular DNA chromosome of 3,284,304 bp was completely assembled and 3,250 protein-encoding genes were predicted. Evolutionarily accelerated genes related to the phenotypic trait of anti-infective activities for influenza virus were identified. These genes encode three integral membrane proteins, a teichoic acid export ATP-binding protein and a glucosamine - fructose-6-phosphate aminotransferase involved in host innate immunity, the nonspecific DNA-binding protein Dps, which protects bacteria from oxidative damage, and the response regulator of the three-component quorum-sensing regulatory system, which is related to the capacity of adhesion to the surface of the respiratory tract and competition with pathogens. This is the first study to identify the genetic backgrounds of the antiviral activity in L. plantarum strains. These findings provide insight into the anti-infective activities of L. plantarum and the development of preventive probiotics.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.249-254
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• 2002

To determine the abilities as both lactic starter and probiotics for fermented foods, we investigated the potency of acid production, proteolytic activity and lactose metabolism of Lactobacillus amylovorus IMC-1. And the strain was cultured with lactococci in 10% skim milk medium. It was also examined the bactericidal action of antibacterial substance, produced by the strain IMC-1, against pathogenic bacteria. L. amylovorus IMC-1 showed excellent production of acid in 10% skim milk supplemented with yeast extract, and produced 0.8 and 2.7% of acid at 12 and 72 h incubation, respectively. It was found that the activity of ${\beta}-galactosidase$, about $39\;{\mu}M/minute/dry$ cell weight (mg), was stronger than that of $phospho-{\beta}-galactosidase$ in the strain IMC-1. The strain showed weak proteolytic activity in 10% skim milk, thus it produced 6 and $69\;{\mu}g/mL$ of free tyrosine at 12 and 72 h cultivation, respectively. It was known that the strain utilized mainly ${\alpha}-casein$ than ${\beta}-casein$ from patterns of SDS-PAGE. Mixed culture produced more acid than single cultures of L. amylovorus IMC-1 and Streptococcus thermophilus NIAI 510. Single culture of Str. thermophilus and mixed culture showed increasing cheese flavor with incubation times. Optimal fermentation time of mixed culture for the acid production and flora of lactic starter was 16 and 12 h by adding 0.1 and 0.5% of yeast extract to 10% skim milk, respectively. Antibacterial substance produced by the strain IMC-1 reduced about 2 log of the viable cell counts of both Escherichia coli O157 and Shigella flexneri after 24 and 4 h incubation, and they were not detected after 48 and 6 h incubation, respectively.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1393-1400
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• 2009

A bacteriocin-producing strain PI80 was isolated from the gut of Penaeus indicus (Indian white shrimp) and identified as Streptococcus phocae PI80. The bacteriocin was purified from a culture supernatant to homogeneity as confirmed by Tricine SDS-PAGE. Reverse-phase HPLC analysis revealed a single active fraction eluted at 12.94 min, and MALDI-TOF mass spectrometry analysis showed the molecular mass to be 9.244 kDa. This molecular mass does not correspond to previously described streptococcal bacteriocins. The purified bacteriocin was named phocaecin PI80 from its producer strain, as this is the first report of bacteriocin production by Streptococcus phocae. The bacteriocin exhibited a broad spectrum of activity and inhibited important pathogens: Listeria monocytogenes, Vibrio parahaemolyticus, and V. fischeri. The antibacterial substance was also sensitive to proteolytic enzymes: trypsin, protease, pepsin, and chymotrypsin, yet insensitive to catalase, peroxidase, and diastase, confirming that the inhibition was due to a proteinaceous molecule (i.e., the bacteriocin), and not due to hydrogen peroxide or diacetyl. Phocaecin PI80 moderately tolerated heat treatment (up to $70^{\circ}C$ for 10 min) and resisted certain solvents (acetone, ethanol, and butanol). A massive leakage of $K^+$ ions from E. coli $DH5\alpha$, L. monocytogenes, and V. parahaemolyticus was induced by phocaecin PI80, as measured by Inductively Coupled Plasma Optical Emission Spectrometry (ICPOES). Therefore, the results of this study show that phocaecin PI80 may be a useful tool for inhibiting L. monocytogenes in seafood products that do not usually undergo adequate heat treatment, whereas the cells of Streptococcus phocae PI80 could be used to control vibriosis in shrimp farming.