• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1675-1686
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• 2016

We characterized the probiotic properties of Lactobacillus helveticus strains KII13 and KHI1 isolated from fermented cow milk by in vitro and in vivo studies. The strains exhibited tolerance to simulated orogastrointestinal condition, adherence to Caco-2 cells, and antimicrobial activity. Both L. helveticus strains produced bioactive tripeptides, isoleucylprolyl-proline and valyl-prolyl-proline, during fermentation of milk. KII13 showed higher in vitro cholesterol-lowering activity (47%) compared with KHI1 (28%) and L. helveticus ATCC 15009 (22%), and hence, it was selected for in vivo study of cholesterol-lowering activity in atherogenic diet-fed hypercholesterolemic mice. For the study, mice were divided into four groups (viz., normal diet control group, atherogenic diet control group (HCD), KII13-atherogenic diet group (HCD-KII13), and Lactobacillus acidophilus ATCC 43121-atherogenic diet group (HCD-L.ac) as positive control). The serum total cholesterol level was significantly decreased by 8.6% and 7.78% in the HCD-KII13 and HCD-L.ac groups (p < 0.05), respectively, compared with the HCD group. Low-density lipoprotein cholesterol levels in both HCD-KII13 and HCD-L.ac groups were decreased by 13% and 11%, respectively, compared with the HCD group (both, p < 0.05). Analysis of cholesterol metabolism-related gene expression in mice liver showed increased expression of LDLR and SREBF2 genes in mice fed with KII13. By comparing all the results, we conclude that L. helveticus KII13 could be used as a potential probiotic strain to produce antihypertensive peptides and reduce serum cholesterol.

• Korean Journal of Plant Resources
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• v.23 no.6
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• pp.526-534
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• 2010

Genomes of clusters of related eukaryotes are now being sequenced at an increasing rate. In this paper, we developed an accurate, low-cost method for annotation of gene prediction and exon-intron structure. The gene prediction was adapted for delta 1-pyrroline-5-carboxylate-synthetase (p5cs) gene from China wild-type of the halophytic Leymus chinensis (Trin.), naturally adapted to highly-alkali soils. Due to complex adaptive mechanisms in halophytes, more attentions are being paid on the regulatory elements of stress adaptation in halophytes. P5CS encodes delta 1-pyrroline-5-carboxylate-synthetase, a key regulatory enzyme involved in the biosynthesis of proline, that has direct correlation with proline accumulation in vivo and positive relationship with stress tolerance. Using analysis of reverse transcription-polymerase chain reaction (RT-PCR) and PCR, and direct sequencing, 1076 base pairs (bp) of cDNA in length and 2396 bp of genomic DNA in length were obtained from direct sequencing results. Through gene prediction and exon-intron structure verification, the full-length of cDNA sequence was divided into eight parts, with seven parts of intron insertion. The average lengths of determinated coding regions and non-coding regions were 154.17 bp and 188.57 bp, respectively. Nearly all splice sites displayed GT as the donor sites at the 5' end of intron region, and 71.43% displayed AG as the acceptor sites at the 3' end of intron region. We conclude that this method is a cost-effective way for obtaining an experimentally verified genome annotation.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.177-184
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• 2009

Three hundred lactic acid bacteria isolated from human feces were studied their probiotic characters to develop potential probiotics. The properties were tested on the basis of guideline for probiotic selection protocol such as tolerance for acid or bile salt, thermal stability, antimicrobial, anticancer cell, and antiviral activity. Strain Miny-148 was selected as a potential probiotic bacterium which showed resistance to low pH, bile salts and thermal stability. On the basis of fatty acid profiles and 16S rDNA sequences analysis, the strain was identified as Lactobacillus pentosus (similarity 99.9%). The strain, L. pentosus Miny-148, showed broad antimicrobial spectrum against E. coli O157:H7, Shigella flexneri, Bacillus anthracis, Staphylococcus aureus, E. coli, Vibrio cholerae, V. vulnificus, Salmonella typhimurium, and Methicillin-resistant S. aureus (MRSA). Cell-free culture supernatant of the strain also inhibited against the growth of HT-29 colon cancer cell and transmissible gastroenterits virus.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.75-84
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• 2016

Probiotics that are able to provide beneficial effects on animal health have become important ingredients of dog foods. This study was conducted to characterize the probiotic potentials of two strains, Lactobacillus reuteri BCLR-42 and Lactobacillus plantarum BCLP-51, that were derived from feces of healthy dogs and evaluated based on tolerance to low pH and bile acid, antimicrobial activities, enzyme profiles, sensitivity to antibiotics, and innate immune enhancing potentials. Both strains showed survival of more than 90% at pH 3 and 0.2% bile acid and exhibited broad antimicrobial activities against indicator bacteria. Moreover, both strains showed high sensitivity to antibiotics, except vancomycin, metronidazole, and gentamicin. The alkaline phosphatase was negligible (score 0), whereas they showed strong beta galactosidase activity (score range 5 or 3, respectively). The phagocytosis and oxidative burst activities of canine granulocytes were significantly enhanced in response to both strains. These results show that both strains have the capability to act as probiotics and the potential for application as ingredients in dog foods.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.501-509
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• 2021

The increasing demand for baked products has given a boost to research on isolation and selection of novel yeast strains with improved leavening activity. Twelve sourdough samples were collected from several localities of the Fez region in Morocco. The pH and total titratable acidity (TTA) values of these samples varied from 3.03-4.63 and 14-17.5 ml of 0.1 N NaOH/10 g of sourdough, respectively, while yeast counts ranged from 5.3 6.77 Log CFU/g. Thirty-two yeast isolates were obtained and evaluated for their leavening ability. Out of all isolates, four yeasts molecularly identified as Saccharomyces cerevisiae (three strains) and Kluyveromyces marxianus (one strain) showed highest specific volumes of 4.69, 4.55, 4.35 and 4.1 cm³/g, respectively. These strains were further assessed for their tolerance to high concentrations of salt, sugar, elevated temperatures, and low pH conditions. K. marxianus showed higher resistance than the S. cerevisiae. Thus, Moroccan sourdoughs harbor technologically relevant yeasts that could be used as potential starters for bread preparation.

• Korean Journal of Environmental Biology
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• v.40 no.3
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• pp.275-280
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• 2022

Suspended solids play an important role in the growth and survival of aquatic organisms. The marine zooplankton species tested in this study were Tigriopus west (Copepoda) and Haustorioides koreanus (Amphipoda) sampled from the intertidal zone, including Artemia nauplii(Branchiopoda) hatched from cysts. The study design included six concentrations (0, 50, 100, 250, 500, and 1,000mg L^-1) of the suspended test particles assayed in triplicate. Experimental cultures in 500 mL-round polycarbonate bottles were subsampled after 96 h to count dead zooplankton. The culture bottles were agitated at 4 RPM on a rotating wheel at 23℃ and 30 PSU. The survival rates of Artemia nauplii and T. west were not affected by suspended solid concentrations higher than 50.0 mg L^-1, whereas the survival rate of H. koreanus decreased with increasing concentrations (p<0.05). In conclusion, H. koreanus and T. west, which were continuously exposed to suspended solid concentrations higher than 50.0 mg L^-1, were affected by low-intensity ecological stress. However, in the case of H. koreanus, a concentration of 50.0 mg L^-1 may be considered to be the limit of tolerance to suspended solids, suggesting that the number of individuals who eventually die will increase if continuously exposed.

• Animal Bioscience
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• v.37 no.8
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• pp.1428-1439
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• 2024

Objective: Compared to Mimas pigeons, Shiqi pigeons exhibit greater tolerance to coarse feeding because of their abundant gut microbiota. Here, to investigate the potential of utilizing intestinal flora derived from Shiqi pigeons, the intestinal flora and body indices of Mimas squabs were evaluated after fecal microbiota transplantation (FMT) from donors. Methods: A total of 90 one-day-old squabs were randomly divided into the control group (CON), the low-concentration group (LC) and the high-concentration group (HC): gavaged with 200 μL of bacterial solution at concentrations of 0, 0.1, and 0.2 g/15 mL, respectively. Results: The results suggested that FMT improved the body weight of Mimas squabs in the HC and LC groups (p<0.01), and 0.1 g/15 mL was the optimal dose during FMT. After 16S rRNA sequencing was performed, compared to those in the CON group, the abundance levels of microflora, especially Lactobacillus, Muribaculaceae, and Megasphaera (p<0.05), in the FMT-treated groups were markedly greater. Random forest analysis indicated that the main functions of key microbes involve pathways associated with metabolism, further illustrating their important role in the host body. Conclusion: FMT has been determined to be a viable method for augmenting the weight and intestinal microbiota of squabs, representing a unique avenue for enhancing the economic feasibility of squab breeding.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.487-492
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• 2002

Low-fat and sugar-free (LFSF) cookies were developed for patients with metabolic syndrome X, such as obesity, diabetes, coronary heart disease, and hypertention, using artificial sweeteners (mixture of aspartame and saccharin), pectin and herb extracts such as Polygonatum Odoratum (Mill) Druce, Schizandrae Fructus and Lycii Fructus, without sugar and fats. LFSF cookies were composed of 7.5 : 1 of aspartame and saccharin, 5% pectin, 49% protein, and 5% herb extracts, with reduced fat level. The values for area under the curve in oral glucose tolerance tests were significantly lower in 90% pancreatomized-(Px, n = 8) and sham - operated (Sham, n = 8) rats which consumed LFSF cookies, than the control, which consumed regular cookies. Blood glucose levels were higher and the peak levels were significantly lower in the LFSF cookies group than the control group of Px and Sham rats. Blood glucose levels of healthy female college students (n = 10) at 30 and 60 min after the consumption of 30 g LFSF and regular cookies were not different, but they were significantly lower in the LFSF-cookies group in diabetes patients (n = 10). In conclusions, LFSF cookies was considered as a good snack for diabetic patients.

• Korean Journal of Environment and Ecology
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• v.26 no.1
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• pp.91-99
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• 2012

The purpose of this study was to find out the vegetation community structure and the distribution characteristics of Buxus koreana through analysis of the topography and soil characteristics in Kwanaksan Ecological and Scenery Conservation Area. To do this twenty two plots as $100m^2$ each were set up and investigated. As a result, the vegetation communities were classified in four groups; Pinus rigida community (I), P. rigida - B. koreana community(II), Quercus mongolica community(III), Quercus acutissima - Quercus serrata community(IV). The distribution characteristics in topography appeared that B. koreana distributed more in valley where soil water and nutrition conditions are good. The drainage condition also influenced the distribution, because the ratio of clay was low in the result of soil texture analysis. B. koreana was distributed in high-pitched slope and the high rock ratio area. According to the soil analysis, the mean soil pH of B. koreana distributed groups(pH 4.79) was higher than that of non-B. koreana distributed groups(pH 4.41). It appeared that B. koreana had tolerance to the barren soil, so the value of exchangeable cations such as $Ca^{2+}$ and $Mg^{2+}$were showed lower than that of the average of Korean forest soil.

• Molecules and Cells
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• v.40 no.4
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• pp.299-306
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• 2017

The transcriptional activator AphB has been implicated in acid resistance and pathogenesis in the food borne pathogens Vibrio vulnificus and Vibrio cholerae. To date, the full-length AphB crystal structure of V. cholerae has been determined and characterized by a tetrameric assembly of AphB consisting of a DNA binding domain and a regulatory domain (RD). Although acidic pH and low oxygen tension might be involved in the activation of AphB, it remains unknown which ligand or stimulus activates AphB at the molecular level. In this study, we determine the crystal structure of the AphB RD from V. vulnificus under aerobic conditions without modification at the conserved cysteine residue of the RD, even in the presence of the oxidizing agent cumene hydroperoxide. A cysteine to serine amino acid residue mutant RD protein further confirmed that the cysteine residue is not involved in sensing oxidative stress in vitro. Interestingly, an unidentified small molecule was observed in the inter-subdomain cavity in the RD when the crystal was incubated with cumene hydroperoxide molecules, suggesting a new ligand-binding site. In addition, we confirmed the role of AphB in acid tolerance by observing an aphB-dependent increase in cadC transcript level when V. vulnificus was exposed to acidic pH. Our study contributes to the understanding of the AphB molecular mechanism in the process of recognizing the host environment.