Journal of Microbiology

Journal Articles

Screening of small molecules attenuating biofilm formation of Acinetobacter baumannii by inhibition of ompA promoter activity: Seok Hyeon Na , Hyejin Jeon , Man Hwan Oh , Yoo Jeong Kim , Je Chul Lee; J. Microbiol. 2021;59(9):871-878. Published online August 27, 2021; DOI: https://doi.org/10.1007/s12275-021-1394-z

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Abstract: Anti-virulence therapeutic strategies are promising alternatives against drug-resistant pathogens. Outer membrane protein A (OmpA) plays a versatile role in the pathogenesis and antimicrobial resistance of Acinetobacter baumannii. Therefore, OmpA is an innovative target for anti-virulence therapy against A. baumannii. This study aimed to develop a high-throughput screening (HTS) system to discover small molecules inhibiting the ompA promoter activity of A. baumannii and screen chemical compounds using the bacterial growth-based HTS system. The ompA promoter and open reading frame of nptI fusion plasmids that controlled the expression of nptI encoding resistance to kanamycin by the ompA promoter were constructed and then transformed into A. baumannii ATCC 17978. This reporter strain was applied to screen small molecules inhibiting the ompA promoter activity in a chemical library. Of the 7,520 chemical compounds, 15 exhibited ≥ 70% growth inhibition of the report strain cultured in media containing kanamycin. Three compounds inhibited the expression of ompA and OmpA in the outer membrane of A. baumannii ATCC 17978, which subsequently reduced biofilm formation. In conclusion, our reporter strain is useful for large-scale screening of small molecules inhibiting the ompA expression in A. baumannii. Hit compounds identified by the HTS system are promising scaffolds to develop novel therapeutics against A. baumannii.

Diversity of lactic acid bacteria from Miang, a traditional fermented tea leaf in northern Thailand and their tannin-tolerant ability in tea extract: Siriporn Chaikaew , Sasitorn Baipong , Teruo Sone , Apinun Kanpiengjai , Naradorn Chui-chai , Kozo Asano , Chartchai Khanongnuch; J. Microbiol. 2017;55(9):720-729. Published online September 2, 2017; DOI: https://doi.org/10.1007/s12275-017-7195-8

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36 Citations

Abstract: The microbiota of lactic acid bacteria (LAB) in thirty-five samples of Miang, a traditional fermented tea leaf product, collected from twenty-two different regions of eight provinces in upper northern Thailand was revealed through the culture-dependent technique. A total of 311 presumptive LAB strains were isolated and subjected to clustering analysis based on repetitive genomic element-PCR (rep-PCR) fingerprinting profiles. The majority of the strains belonged to the Lactobacillus genera with an overwhelming predominance of the Lb. plantarum group. Further studies of species-specific PCR showed that 201 of 252 isolates in the Lb. plantarum group were Lb. plantarum which were thus considered as the predominant LAB in Miang, while the other 51 isolates belonged to Lb. pentosus. In contrast to Lb. plantarum, there is a lack of information on the tannase gene and the tea tannin-tolerant ability of Lb. pentosus. Of the 51 Lb. pentosus isolates, 33 were found to harbor the genes encoding tannase and shared 93-99% amino acid identity with tannase obtained from Lb. pentosus ATCC 8041T. Among 33 tannase gene-positive isolates, 23 isolates exhibited high tannin- tolerant capabilities when cultivated on de Man Rogosa and Sharpe agar-containing bromocresol purple (0.02 g/L, MRS-BCP) supplemented with 20% (v/v) crude tea extract, which corresponded to 2.5% (w/v) tannins. These Lb. pentosus isolates with high tannin-tolerant capacity are expected to be the high potential strains for functional tannase production involved in Miang fermentation as they will bring about certain benefits and could be used to improve the fermentation of tea products.

Potential use of lactic acid bacteria Leuconostoc mesenteroides as a probiotic for the removal of Pb(II) toxicity: Young-Joo Yi , Jeong-Muk Lim , Suna Gu , Wan-Kyu Lee , Eunyoung Oh , Sang-Myeong Lee , Byung-Taek Oh; J. Microbiol. 2017;55(4):296-303. Published online March 31, 2017; DOI: https://doi.org/10.1007/s12275-017-6642-x

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76 Citations

Abstract: It has been demonstrated that certain lactic acid bacteria (LAB) can sequester metal ions by binding them to their surfaces. In the present study, lead (Pb)-resistant LAB were isolated from kimchi, a Korean fermented food. A total of 96 different LAB strains were isolated, and 52 strains showed lead resistance. Among them, an LAB strain-96 (L-96) iden-tified as Leuconostoc mesenteroides showed remarkable Pb resistance and removal capacity. The maximum adsorption capacity of this strain calculated using the Langmuir isotherm was 60.6 mg Pb/g. In an in vivo experiment, young male mice were provided with water (A), Pb-water (B), or Pb-water+ L-96 (C) during puberty. Lower glutamate oxaloacetate trans-aminase (GOT) and glutamate pyruvate transaminase (GPT) levels in Pb-exposed male mice that received strain L-96 as a probiotic were suggestive of reduced hepatotoxicity. More-over, feces from mice treated with L-96 contained more Pb than feces from untreated mice. Increased Pb elimination likely reduced internal accumulation, and this hypothesis was supported by significantly lower Pb concentrations in kid-neys and testes of the mice treated with strain L-96. The mo-tility and ATP content of epididymal spermatozoa were par-tially restored if strain L-96 was administered. In conclusion, isolated L-96 LAB had lead-biosorption activity and effi-ciently detoxified lead-poisoned male mice, resulting in re-covering male reproductive function. These results suggest the potential use of LAB as a probiotic to protect humans from the adverse effects of Pb exposure.

A lactic acid bacterium isolated from kimchi ameliorates intestinal inflammation in DSS-induced colitis: Jin-Soo Park , Inseong Joe , Paul Dong Rhee , Choon-Soo Jeong , Gajin Jeong; J. Microbiol. 2017;55(4):304-310. Published online January 26, 2017; DOI: https://doi.org/10.1007/s12275-017-6447-y

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48 Citations

Abstract: Some species of lactic acid bacteria have been shown to be beneficial in inflammatory bowel disease (IBD). In the pre-sent study, a strain of lactic acid bacterium (Lactobacillus paracasei LS2) was isolated from the Korean food, kimchi, and was shown to inhibit the development of experimental colitis induced by dextran sulfate sodium (DSS). To inves-tigate the role of LS2 in IBD, mice were fed DSS in drinking water for seven days along with LS2 bacteria which were administered intragastrically to some of the mice, while phos-phate-buffered saline (PBS) was administered to others (the controls). The administration of LS2 reduced body weight loss and increased survival, and disease activity indexes (DAI) and histological scores indicated that the severity of colitis was significantly reduced. The production of inflammatory cy-tokines and myeloperoxidase (MPO) activity also decreased. Flow cytometry analysis showed that the number of Th1 (IFN-γ) population cells was significantly reduced in the LS2- administered mice compared with the controls. The admini-stration of LS2 induced the increase of CD4+FOXP3+ Treg cells, which are responsible for IL-10. Numbers of macro-phages (CD11b+ F4/80+), and neutrophils (CD11b+ Gr-1+) among lamina propria lymphocytes (LPL) were also reduced. These results indicate that LS2 has an anti-inflammatory effect and ameliorates DSS-induced colitis.

Research Support, Non-U.S. Gov't

Genome sequence analysis of potential probiotic strain Leuconostoc lactis EFEL005 isolated from kimchi: Jin Seok Moon , Hye Sun Choi , So Yeon Shin , Sol Ji Noh , Che Ok Jeon , Nam Soo Han; J. Microbiol. 2015;53(5):337-342. Published online May 3, 2015; DOI: https://doi.org/10.1007/s12275-015-5090-8

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19 Citations

Abstract: Leuconostoc lactis EFEL005 (KACC 91922) isolated from kimchi showed promising probiotic attributes; resistance against acid and bile salts, absence of transferable genes for antibiotic resistance, broad utilization of prebiotics, and no hemolytic activity. To expand our understanding of the species, we generated a draft genome sequence of the strain and analyzed its genomic features related to the aforementioned probiotic properties. Genome assembly resulted in 35 contigs, and the draft genome has 1,688,202 base pairs (bp) with a G+C content of 43.43%, containing 1,644 protein-coding genes and 50 RNA genes. The average nucleotide identity analysis showed high homology (≥ 96%) to the type strain L. lactis KCTC3528, but low homology (≤ 95%) to L. lactis KCTC3773 (formerly L. argentinum). Genomic analysis revealed the presence of various genes for sucrose metabolism (glucansucrases, invertases, sucrose phosphorylases, and mannitol dehydrogenase), acid tolerance (F1F0 ATPases, cation transport ATPase, branched-chain amino acid permease, and lysine decarboxylase), vancomycin response regulator, and antibacterial peptide (Lactacin F). No gene for production of biogenic amines (histamine and tyramine) was found. This report will facilitate the understanding of probiotic properties of this strain as a starter for fermented foods.

Journal Article

Use of Selected Lactic Acid Bacteria in the Eradication of Helicobacter pylori Infection: Jin-Eung Kim , Min-Soo Kim , Yeo-Sang Yoon , Myung-Jun Chung , Do-Young Yum; J. Microbiol. 2014;52(11):955-962. Published online October 3, 2014; DOI: https://doi.org/10.1007/s12275-014-4355-y

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26 Citations

Abstract: Helicobacter pylori is among the major pathogenic bacteria that cause chronic gastritis and peptic ulcer disease and is related to the development of gastric cancer. Several chemicals, including antibiotics, have been used to eradicate H. pylori; however, they do not always curb the infection. Ten representative type strains of lactic acid bacteria (LAB) were screened for antagonism toward H. pylori via inhibition of urease activity. Strains inhibiting the binding of H. pylori to human gastric cell line cells and suppressing H. pylori-induced interleukin-8 (IL-8) production were also screened. Of these, Pediococcus pentosaseus (SL4), which inhibited the adhesion of H. pylori to MKN-45 gastric cancer cells, Bifidobacterium longum (BG7), with urease inhibiting activity, and Lactococcus lactis (SL3), and Enterococcus faecalis (SL5), which suppressed H. pylori-induced IL-8 production within MKN-45 and AGS cells, were selected. In mouse model, these LAB stains in combination significantly suppressed IL-8 levels in serum. Gastric pH also recovered to normal values after the administration of these LAB. These stains effectively suppressed H. pylori viability, although not to the extent of antibiotic treatment. When used as probiotics, LAB may help decrease the occurrence of gastritis and reduce the risk of H. pylori infection without, inducing side effects.

Research Support, Non-U.S. Gov'ts

Antifungal Activity of Leuconostoc citreum and Weissella confusa in Rice Cakes: Eunjong Baek , Hyojin Kim , Hyejung Choi , Sun Yoon , Jeongho Kim; J. Microbiol. 2012;50(5):842-848. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2153-y

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49 Citations

Abstract: The antifungal activity of organic acids greatly improves the shelf life of bread and bakery products. However, little is known about the effect of lactic acid fermentation on fungal contamination in rice cakes. Here, we show that lactic acid fermentation in rice dough can greatly retard the growth of three fungal species when present in rice cakes, namely Cladosporium sp. YS1, Neurospora sp. YS3, and Penicillium crustosum YS2. The antifungal activity of the lactic acid bacteria against these fungi was much better than that of 0.3% calcium propionate. We found that organic acids including lactic and acetic acid, which are byproducts of lactic fermentation or can be artificially added, were the main antifungal substances. We also found that some Leuconostoc citreum and Weissella confusa strains could be good starter species for rice dough fermentation. These results imply that these lactic acid bacteria can be applicable to improve the preservation of rice cakes.

NOTE] Antibiotic Resistance and Probiotic Properties of Dominant Lactic Microflora from Tungrymbai, an Ethnic Fermented Soybean Food of India: Sharmila Thokchom , Santa Ram Joshi; J. Microbiol. 2012;50(3):535-539. Published online June 30, 2012; DOI: https://doi.org/10.1007/s12275-012-1409-x

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15 Citations

Abstract: The present investigation was conducted to assess lactic acid bacteria present in traditionally fermented food of ethnic tribes in India for probiotic properties, antibacterial activity, and antibiotic tolerance behavior. Enterococcus sp., Lactobacillus sp., and Lactococcus sp. showed antibacterial activity against Bacillus cereus MTCC 430, Staphylococcus aureus subsp. aureus MTCC 740, and Salmonella enterica ser. paratyphi A MTCC 735. Lactococcus sp. and Lactobacillus sp. could tolerate acidic conditions (pH 2) and high bile salt concentration (4000 ppm). The lactic microflora were found to be sensitive to most common antibiotics, except for cloxacillin (5 μg), cephalexin (30 μg), and cephalothin (30 μg).

Phenotypic and Phylogenetic Analysis of Lactic Acid Bacteria Isolated from Forage Crops and Grasses in the Tibetan Plateau: Huili Pang , Zhongfang Tan , Guangyong Qin , Yanping Wang , Zongwei Li , Qingsheng Jin , Yimin Cai; J. Microbiol. 2012;50(1):63-71. Published online February 27, 2012; DOI: https://doi.org/10.1007/s12275-012-1284-5

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53 Citations

Abstract: A total of 140 lactic acid bacteria (LAB) strains were isolated from corn, alfalfa, clover, sainfoin, and Indian goosegrass in the Tibetan Plateau. According to phenotypic and chemotaxonomic characteristics, 16S rDNA sequence, and recA gene PCR amplification, these LAB isolates were identified as belonging to five genera and nine species. Corn contained more LAB species than other forage crops. Leuconostoc pseudomesenteroides, Lactococcus lactis subsp. lactis, Lactobacillus brevis, and Weissella paramesenteroides were dominant members of the LAB population on alfalfa, clover, sainfoin, and Indian goosegrass, respectively. The comprehensive 16S rDNA and recA-based approach effectively described the LAB community structure of the relatively abundant LAB species distributed on different forage crops. This is the first report describing the diversity and natural populations of LAB associated with Tibetan forage crops, and most isolates grow well at or below 10°C. The results will be valuable for the future design of appropriate inoculants for silage fermentation in this very cold area.

Journal Article

A Selected Probiotic Strain of Lactobacillus fermentum CM33 Isolated from Breast-Fed Infants as a Potential Source of β-Galactosidase for Prebiotic Oligosaccharide Synthesis: Wattana Sriphannam , Saisamorn Lumyong , Piyanuch Niumsap , Hisashi Ashida , Kenji Yamamoto , Chartchai Khanongnuch; J. Microbiol. 2012;50(1):119-126. Published online February 27, 2012; DOI: https://doi.org/10.1007/s12275-012-1108-7

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20 Citations

Abstract: Lactic acid bacteria from healthy breast-fed infants were isolated and screened for β-galactosidase production in MRS broth. Among 49 isolates that exhibited the yellow clear zone on MRS agar supplemented with bromocresol blue, the isolate CM33 was selected as being the highest β-galactosidase producer and was identified as Lactobacillus fermentum based on its morphological characteristics and 16S rDNA nucleotide sequence. L. fermentum CM33 exhibited a good survival rate under the simulated stomach passage model, comparable to known probiotic strains L. gallinarum JCM2011 and L. agilis JCM1187. L. fermentum CM33 was antagonistic to pathogenic bacteria Listeria monocytogenes, Escherichia coli 0157:H7, Salmonella typhi, and Salmonella enteriditis, using the well diffusion method. In addition, the selected lactobacilli exhibited a high growth rate when cultivated in modified MRS containing commercial galactooligosaccharide (GOS) as a sole carbon source, as well as in glucose. A preliminary study on the enzymatic synthesis of oligosaccharide using crude β-galactosidase revealed the capability for oligosaccharide synthesis by the transgalactosylation activity.

Research Support, Non-U.S. Gov't

Isolation and Characterization of Lactic Acid Bacteria Strains with Ornithine Producing Capacity from Natural Sea Salt: Jin-Ju Yu , Suk-Heung Oh; J. Microbiol. 2010;48(4):467-472. Published online August 20, 2010; DOI: https://doi.org/10.1007/s12275-010-0204-9

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19 Citations

Abstract: Two lactic acid bacteria (LAB) having ornithine-producing capacity were isolated from Korean natural sea salt. They were Gram-positive, short rod-type bacteria, and able to grow anaerobically with CO2 production. The isolates grew well on MRS broth at 30-37°C and a pH of 6.5-8.0. The optimum temperature and pH for growth are 37°C and pH 7.0. The isolates fermented D-ribose, D-galactose, D-lactose, D-maltose, Dcellobiose, D-tagatose, D-trehalose, sucrose, D-melezitose, gentiobiose, D-glucose but not D-melibiose, inositol, and L-sorbose. The 16S rDNA sequences of the two isolates showed 99.5% and 99.6% homology with the Weissella koreensis S5623 16S rDNA (Access no. AY035891). They were accordingly identified and named as Weissella koreensis MS1-3 and Weissella koreensis MS1-14, and produced intracellular ornithine at levels of 72 mg/100 g cell F.W. and 105 mg/100 g cell F.W. and extracellular ornithine at levels of 4.5 mg/100 ml and 4.6 mg/100 ml medium, respectively, by culturing in MRS broth supplemented with 1% arginine. High cell growth was maintained in MRS broth with a NaCl concentration of 0-6%. These results show for the first time that Korean natural sea salts contain lactic acid bacteria Weissella koreensis strains having ornithine producing capacity.

Journal Article

Characterization of Exopolysaccharide (EPS) Produced by Weissella hellenica SKkimchi3 Isolated from Kimchi: Min Ju Kim , Ha Na Seo , Tae Sik Hwang , Sung Hun Lee , Doo Hyun Park; J. Microbiol. 2008;46(5):535-541. Published online October 31, 2008; DOI: https://doi.org/10.1007/s12275-008-0134-y

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54 Citations

Abstract: Weissella hellenica SKkimchi3 produces the higher exopolysaccharide (EPS) on sucrose than lactose, glucose, and fructose at pH 5 and 20°C. Sucrose was exclusively used to cultivate SKkimchi3 in all experiments base on the EPS production tests. The molecular mass of EPS, as determined by gel permeation chromatography, was 203,000. 1H and 13C NMR analysis indicated that the identity of EPS may be a glucan. When EPS, starch, and cellulose was treated with α-amylase, glucoamylase, glucosidase, and cellulase, glucose was produced from starch and cellulose but was not produced from EPS. Based on HPLC analysis, elemental analysis, 1H and 13C NMR analysis, and enzymatic hydrolysis tests, EPS was estimated to be a glucan. EPS suspension was not precipitated even by centrifugation at 10,000×g for 60 min, and EPS made the fermented milk and bacterial culture viscous.

Research Support, Non-U.S. Gov'ts

Probiotication of Tomato Juice by Lactic Acid Bacteria: Kyung Young Yoon , Edward E. Woodams , Yong D Hang; J. Microbiol. 2004;42(4):315-318.; DOI: https://doi.org/2105 [pii]

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Abstract: This study was undertaken to determine the suitability of tomato juice as a raw material for production of probiotic juice by four lactic acid bacteria (Latobacillus acidophilus LA39, Lactobacillus plantarum C3, Lactobacillus casei A4, and Lactobacillus delbrueckii D7). Tomato juice was inoculated with a 24-h-old culture and incubated at 30oC. Changes in pH, acidity, sugar content, and viable cell counts during fermentation under controlled conditions were measured. The lactic acid cultures reduced the pH to 4.1 or below and increased the acidity to 0.65% or higher, and the viable cell counts (CFU) reached nearly 1.0 to 9.0x10^9/ml after 72 h fermentation. The viable cell counts of the four lactic acid bacteria in the fermented tomato juice ranged from 10^6 to 10^8 CFU/ml after 4 weeks of cold storage at 4oC. Probiotic tomato juice could serve as a health beverage for vegetarians or consumers who are allergic to dairy products.

Free Fatty Acid Accumulation by Mesophilic Lactic Acid Bacteria in Cold-Stored Milk: Hayri Co kun , Eda Ondul; J. Microbiol. 2004;42(2):133-138.; DOI: https://doi.org/2033 [pii]

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Abstract: This study was aimed to determine the accumulation of free fatty acid by mesophilic lactic acid bacteria (Lactococcus lactis subsp. lactis 1471, Lactococcus lactis subsp. cremoris 1000 and Lactobacillus casei 111) in cold-stored milk. According to the results, all cold-stored milks had higher acid degree values than those of fresh milk. This phenomenon showed that a slight increase occurred in the accumulation of free fatty acids as a result of spontaneous lipolysis during cold storage. All lactic acid bacteria showed good performance in production of titratable acidity, which increased during fermentation of the milk (fresh and stored milks). Moreover, as the storage time was prolonged, more free fatty acid accumulation was obtained from the fermentation of the cold-stored milk by the investigated lactic acid bacteria. The control milk, which was without lactic acid bacteria, showed no change in the accumulation of free fatty acid during fermentation. From this result, it can be suggested that longer cold-storage time can induce higher free fatty acid accumulation in milk by lactic acid bacteria.

Analysis of cellular fatty acid methyl esters (FAMEs) for the identification of leuconostoc strains isolated from kimchi: Lee, Jung Sook , Chun, Chang Ouk , Kim, hong Joong , Joo, Yun Jung , Lee, Hun Joo , Park, Chan Sun , Ahn, Jong Seog , Park, Yong Ha , Mheen, Tae Ickc; J. Microbiol. 1996;34(3):225-228.

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Abstract: The cellular fatty acid methyl esters (FAMEs) analysis data obtained for clusters defined at a Euclidian distance of 17.5, in the classification of lactic acid bacteria isolated from kimchi, described by Lee et al. (4), was used for the identification of 79 Leuconostoc isolates. The test strains were isolated using a selective isolation medium specific for the genus Leuconostoc. These strains were then characterized according to their fatty acid profiles. The results show that all seventy nine test strains were identified to the known Leucomostock clusters B, C, and D. Cluster B had the highest relative amount of the saturated fatty acid 16 : 0. The saturated fatty acid 16 : 0 and summed feature 9 were found as a major components in cluster C, which had a higher level of summed feature 9 than cluster B. Cluster D is characterized by the highest relative amount of the unsaturated fatty acid 18 : 1 w9c. It is suggested that FAMEs analysis can be successfully applied in the identification of lactic acid bacteria isolated from kimchi.

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