• Korean Journal of Microbiology
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• v.40 no.1
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• pp.1-6
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• 2004

Tetracycline resistant bacterial strains were isolated from 10 batches of Kimchi among 50 batches collected in Taegu restrict. The MIC of tetracycline ranged between 25 and> 100 ㎖/l. Total genomic DNA preparation from all 10 tetracycline resistant lactic acid bacterial isolates were subjected to PCR amplification with class-specific primers for tet(M) and tet(O). In only one isolate, HJ9, tet(M) was detected. By Southern blotting and hybridization with a tet(M)-specific probe, the tet(M) gene of HJ9 isolate could be localized on a plasmid. The partial nucleotide sequence and deduced amino acid sequence of tet(M) of HJ9 showed 90-99% and 94-100% homology to those of Gram positive bacteria, respectively. With sequencing of 16S rRNA, HJ9 isolate from Kimchi was identified as Lactobacillus sakei. From these results, Kimchi can be considered potential vehicle for the spread of antibiotic-resistant lactic acid bacteria along the food chain to the consumer.

• Genes and Genomics
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• v.40 no.11
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• pp.1225-1235
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• 2018

Hypoxia seriously affects the innate immune system of fish. However, the roles of suppressor of cytokine signaling (SOCS), pivotal anti-inflammatory genes, in response to hypoxia/reoxygenation remain largely unexplored. The primary objective of this study was to elucidate the function of SOCS genes under acute hypoxia and reoxygenation in pufferfish (Takifugu fasciatus). In the present study, SOCS1, 2 and 3 were identified in T. fasciatus referred to as TfSOCS1, 2 and 3. Then, qRT-PCR and western blot analysis were employed to assess their expressions at both the mRNA and protein levels. Tissue distribution demonstrated that the three SOCS genes were predominantly distributed in gill, brain and liver. Under hypoxia challenge ($1.63{\pm}0.2mg/L$ DO for 2, 4, 6 and 8 h), the expressions of TfSOCS1 and 3 in brain and liver at the mRNA and protein levels were significantly decreased, while their expressions showed an opposite trend in gill. Different from the expressions of TfSOCS1 and 3, the expression of TfSOCS2 was inhibited in gill, along with its increased expression in brain and liver. After normoxic recovery ($7.0{\pm}0.3mg/L$ of DO for 4 and 12 h), most of TfSOCS genes were significantly altered at R4 (reoxygenation for 4 h) and returned to the normal level at R12 (reoxygenation for 12 h). SOCS genes played vital roles in response to hypoxia/reoxygenation challenge. Our findings greatly strengthened the relation between innate immune and hypoxia stress in T. fasciatus.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1778-1782
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• 2017

To identify and discriminate the bacterial species at the subspecific level, rep-PCR is a reliable genomic fingerprinting tool. Fourteen strains of bacteria were isolated from different food sources, identified as Leuconostoc citreum using 16S rRNA gene sequencing, and amplified using rep-primers (REP, ERIC, and $(GTG)_5$). Fingerprinting patterns generated bands in the range of 300-6,000 bp with REP, 150-6,000 bp with ERIC, and 200-1,700 bp with $(GTG)_5$ primers. In UPGMA dendrogram analysis, 14 strains were clustered into three clades (I, II, and III) with all the primers, thus differentiating them at the molecular level. The present study revealed the differentiation of L. citreum strains using rep-PCR.

• Kosin Medical Journal
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• v.33 no.3
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• pp.422-430
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• 2018

Leuconostoc species are Gram-positive coccobacilli and are used in dairy products and are intrinsically resistant to vancomycin. Leuconostoc infections are rare in humans, usually occurring in immune-compromised patients. We describe 6 patients with Leuconostoc bacteremia at Dong-A university hospital between 1990 and 2015. One isolate (L. lactis) was identified to species level using 16S rRNA gene sequencing analysis. All patients had underlying diseases and 5 patients underwent procedures that interrupted the normal integumentary defense. Four patients died within 30 days after being identified as carrying Leuconostoc species.

• Journal of Veterinary Science
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• v.23 no.3
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• pp.41.1-41.15
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• 2022

Background: Proliferative enteritis caused by Lawsonia intracellularis undermines the economic stability of the swine industry worldwide. The development of cost-effective animal models to study the pathophysiology of the disease will help develop strategies to counter this bacterium. Objectives: This study focused on establishing a model of gastrointestinal (GI) infection of L. intracellularis in C57BL/6 mice to evaluate the disease progression and lesions of proliferative enteropathy (PE) in murine GI tissue. Methods: We assessed the murine mucosal and cell-mediated immune responses generated in response to inoculation with L. intracellularis. Results: The mice developed characteristic lesions of the disease and shed L. intracellularis in the feces following oral inoculation with 5 × 10⁷ bacteria. An increase in L. intracellularis 16s rRNA and groEL copies in the intestine of infected mice indicated intestinal dissemination of the bacteria. The C57BL/6 mice appeared capable of modulating humoral and cell-mediated immune responses to L. intracellularis infection. Notably, the expression of genes for the vitamin B12 receptor and for secreted and membrane-bound mucins were downregulated in L. intracellularis -infected mice. Furthermore, L. intracellularis colonization of the mouse intestine was confirmed by the immunohistochemistry and western blot analyses. Conclusions: This is the first study demonstrating the contributions of bacterial chaperonin and host nutrient genes to PE using an immunocompetent mouse model. This mouse infection model may serve as a platform from which to study L. intracellularis infection and develop potential vaccination and therapeutic strategies to treat PE.

• Biomolecules & Therapeutics
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• v.20 no.1
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• pp.43-49
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• 2012

Stimulation of mast cells through the high affinity IgE receptor (Fc${\varepsilon}$RI) induces degranulation, lipid mediator release, and cytokine secretion leading to allergic reactions. Although various signaling pathways have been characterized to be involved in the Fc${\varepsilon}$RI-mediated responses, little is known about the precious mechanism for the expression of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in mast cells. Here, we report that rapamycin, a specific inhibitor of mammalian target of rapamycin (mTOR), reduces the expression of TNF-${\alpha}$ in rat basophilic leukemia (RBL-2H3) cells. IgE or specific antigen stimulation of RBL-2H3 cells increases the expression of TNF-${\alpha}$ and activates various signaling molecules including S6K1, Akt and p38 MAPK. Rapamycin specifically inhibits antigeninduced TNF-${\alpha}$ mRNA level, while other kinase inhibitors have no effect on TNF-${\alpha}$ mRNA level. These data indicate that mTOR signaling pathway is the main regulation mechanism for antigen-induced TNF-${\alpha}$ expression. TNF-${\alpha}$ mRNA stability analysis using reporter construct containing TNF-${\alpha}$ adenylate/uridylate-rich elements (AREs) shows that rapamycin destabilizes TNF-${\alpha}$ mRNA via regulating the AU-rich element of TNF-${\alpha}$ mRNA. The antigen-induced activation of S6K1 is inhibited by specific kinase inhibitors including mTOR, PI3K, PKC and $Ca^{2+}$chelator inhibitor, while TNF-${\alpha}$ mRNA level is reduced only by rapamycin treatment. These data suggest that the effects of rapamycin on the expression of TNF-${\alpha}$ mRNA are not mediated by S6K1 but regulated by mTOR. Taken together, our results reveal that mTOR signaling pathway is a novel regulation mechanism for antigen-induced TNF-${\alpha}$ expression in RBL-2H3 cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.573-581
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• 2016

Bacterial decarboxylation of amino acids in food leads to the production of biogenic amines, which can cause reactions in human that include headaches, nausea, palpitations, chills, and severe respiratory distress. The amine putrescine is an especially effective inhibitor of metabolizing enzymes and amplifies histamine intoxication and tyramine poisoning. Using an L-ornithine decarboxylating medium, we isolated 14 putrescine-producing bacteria from sand lance, Ammodytes personatus, sauces. The isolates were identified, using an API kit and 16S rRNA analysis, as Lysinibacillus fusiformis (1 strain), Lysinibacillus xylanilyticus (6 strains), Lysinibacillus macroides (1 strain), Lysinibacillus sphaericus (3 strains), Bacillus fusiformis (1 strain), Paenibacillus favisporus (1 strain), and Staphylococcus caprae (1 strain). These strains produced between 1.66 to 236.97 μg/mL of putrescine after 48 h incubation. Lysinibacillus spp. were the dominant putrescine-producing bacteria in sand lance sauces, which produced 236.97 μg/mL of putrescine from a culture broth containing 0.5% L-ornithine. This is the first report on the isolation and identification of putrescine-producing bacteria from sand lance sauces.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.1
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• pp.31-38
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• 2014

Docosahexaenoic acid (DHA, 22:6n-3) and ecosapentaenoic acid (20:5n-3) have attracted increasing attention since the first epidemiological report on the importance of n-3 essential fatty acids. It is thought that DHA has important functions in brain and retinal tissues. Thraustochytrids, a group of marine protists, are capable of heterotrophic growth, and are potential omega-3 producers for industrial use, especially the members of the Schizochytrium and Thraustochytrium genera. The aims of this work were to isolate, identify and screen thraustochytrids from 17 different locations. Twenty-three isolates were screened for biomass, total fatty acid (TFA) and DHA content. Analysis of the fatty acid methyl esters revealed four distinct clusters biomass ranged from $8.68-9.36gL^{-1}$, and lipid and DHA contents ranged from $3.11-4.10gL^{-1}$ and $1.05-1.93gL^{-1}$ biomass, respectively. B-12 isolates were screened for biomass ($9.36gL^{-1}$), TFA ($4.10gL^{-1}$) and DHA (47.01%, w/w) content. C-6 isolates were also screened for biomass ($8.92gL^{-1}$), TFA ($3.30gL^{-1}$) and DHA (49.41%, w/w) content. The 18S rRNA gene sequencing results identified Schizochytrium mangrovei as B-12 and Crypthecodium cohnii as C-6.

• Journal of Life Science
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• v.31 no.5
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• pp.496-501
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• 2021

In this study, the marine agar-degrading bacterium Pseudoalteromonas sp. JH-1 was isolated, and its growth and agarase properties were investigated. Seawater was collected from the offshore of the Yonggung Temple in Busan, and agar-degrading bacteria were isolated and cultured with marine agar medium. The bacterium Pseudoalteromonas sp. JH-1 was isolated through 16S rRNA gene sequencing. The extracellularly secreted enzyme was obtained from the culture broth of Pseudoalteromonas sp. JH-1 and was used to characterize its agarase. The extracellular agarase exhibited a maximum activity of 116.6 U/l at 50℃ and pH 6.0 of 20 mM Tris-HCl buffer. Relative activities were 31, 59, 94, 100, 45, and 31% at 20, 30, 40, 50, 60, and 70℃, respectively. Relative activities were 49, 85, 100, 86, 81, and 67% at pH 4, 5, 6, 7, 8, and 9, respectively. Residual activity was more than 85% after exposure at 20, 30, and 40℃ for 2 hr, and more than 82% after exposure at 50℃ for 2 hr. Zymogram analysis confirmed that Pseudoalteromonas sp. JH-1 produced at least two agarases of 55 and 97 kDa. As the products of α-agarase and β-agarase have antioxidation, antitumor, skin-whitening, macrophage activation, and prebiotic effects, further studies are needed on the agarase of Pseudoalteromonas sp. JH-1.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.442-446
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• 2007

From the rhizoplane and rhizosphere of pepper, tomato, lettuce, pasture, and grass, unsoluble inorganic phosphate solubilizing bacterial strains were isolated using plate base assay on Pikovskaya's medium. Two strains, CL-1 and CL-2, which produced largest halo on plates (indicative of phosphate solubilization)were selected for further studies. Based on these biochemical and 16S rRNA analysis strains CL-1, CL-2 were found to be as species of Pseudomonas sp. and Kluyvera sp., respectively. In broth assay Pseudomonas sp. CL-1 and Kluyvera sp. CL-2 solubilized insoluble phosphate by 193.4 mg and $493.6P\;mg\;L^{-1}$, respectively after $3^{rd}$ day inoculation. These effecient phosphate solubilizing bacteria have a potential to be developed as microbial based fertilizer in future.