• Journal of Microbiology and Biotechnology
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• 제32권3호
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• pp.341-347
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• 2022

In this study, the bacterial community of galchi-baechu kimchi was determined using culture-based and culture-independent techniques (next generation sequencing:NGS), and showed discrepancies between results. Weissella koreensis and Pediococcus inopinatus were the dominant species according to the NGS results, while Bacillus species and P. inopinatus were dominant in the culture-dependent analysis. To identify safe starter candidates, sixty-five Bacillus strains isolated from galchi-baechu kimchi using culture-dependent methods were evaluated for their antibiotic resistance, presence of toxin genes, and hemolytic activity. Strains were then assessed for salt tolerance and protease and lipase activity. As a result, four strains-B. safensis GN5_10, B. subtilis GN5_19, B. velezensis GN5_25, and B. velezensis GT8-were selected as safe starter candidates for use in fermented foods.

• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1253-1261
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• 2022

Staphylococcus aureus (S. aureus) infection causes dramatic harm to human health as well as to livestock development. As an important virulence factor, alpha-hemolysin (hla) is critical in the process of S. aureus infection. In this report, we found that bavachin, a natural flavonoid, not only efficiently inhibited the hemolytic activity of hla, but was also capable of inhibiting it on transcriptional and translational levels. Moreover, further data revealed that bavachin had no neutralizing activity on hla, which did not affect the formation of hla heptamers and exhibited no effects on the hla thermal stability. In vitro assays showed that bavachin was able to reduce the S. aureus-induced damage of A549 cells. Thus, bavachin repressed the lethality of pneumonia infection, lung bacterial load and lung tissue inflammation in mice, providing potent protection to mice models in vivo. Our results indicated that bavachin has the potential for development as a candidate hla inhibitor against S. aureus.

• 한국임상수의학회지
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• 제40권4호
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• pp.288-293
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• 2023

A 11-year-old neutered male Maltese dog was vaccinated with a rabies vaccine (Rabisin^®, Boehringer Ingelheim International GmbH, Germany) subcutaneously at a local animal hospital. One hour after vaccination, purpura with edema was observed at the injection site and severe thrombocytopenia (0 K/μL) was noted on a complete blood count (CBC). No specific findings were found in serum chemistry, electrolyte, blood gas analysis, and coagulation tests. The patient was hospitalized and administered antihemorrhagic agents (vitamin K, desmopressin), antihistamines (chlorpheniramine) and corticosteroids (methylprednisolone sodium succinate). On a repeat CBC, mild anemia had developed, thrombocytopenia was still noted, and autoagglutination was observed on a saline agglutination test (SAT). A polymerase chain reaction panel for infectious agents (e.g., Babesia spp.) was negative. The diagnosis was secondary immune-mediated thrombocytopenia (IMT) with immune-mediated hemolytic anemia (IMHA) associated with vaccination. Therefore, the immunosuppressants (prednisolone, and mycophenolate mofetil) were administered. Six days after drug administration, new lesion was not observed, and the previous lesions were significantly improved. It gradually improved and 4 weeks after hematocrit and platelet recovered to normal levels. It was maintained for 6 months without recurrence of related symptoms. Based on patient's history and test results, the patient was diagnosed with Evans' syndrome associated with rabies vaccine.

• 한국미생물·생명공학회지
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• 제51권2호
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• pp.167-173
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• 2023

Proteolytic enzymes secreted by Aspergillus, as pathogenicity factors, affect blood coagulation and fibrinolysis, and therefore the target proteins of their action in the bloodstream are of significant interest. In the present study, the action of the isolated protease of A. terreus 2 on different human plasma proteins was shown. The protease of A. terreus 2 exhibited the highest proteolytic activity against hemoglobin, which was 2.5 times higher than the albuminolytic activity shown in both of the protein substrates used. In addition, the protease has significant ability to hydrolyze both fibrin and fibrinogen. However, the inability of the A. terreus 2 protease to coagulate rabbit blood plasma and coagulate human and bovine fibrinogen indicates the severity of the enzyme's action on human blood coagulation factors. It should be considered as a potential indicator of this isolated protease's participation in fungal pathogenesis. The protease shows no hemolytic activity. Furthermore, its activity is insignificantly inhibited by thrombin inhibitors, and is not inhibited by plasmin inhibitors.

• Journal of Microbiology and Biotechnology
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• 제33권12호
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• pp.1625-1634
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• 2023

Leuconostoc lactis strain DMLL10 was isolated from kimchi, a fermented vegetable, as a starter candidate through safety and technological assessments. Strain DMLL10 was susceptible to ampicillin, chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, streptomycin, and tetracycline. It did not show any hemolytic activity. Regarding its phenotypic results related to its safety properties, genomic analysis revealed that strain DMLL10 did not encode for any toxin genes such as hemolysin found in the same genus. It did not acquire antibiotic resistance genes either. Strain DMLL10 showed protease activity on agar containing NaCl up to 3%. The genome of DMLL10 encoded for protease genes and possessed genes associated with hetero- and homo-lactic fermentative pathways for lactate production. Finally, strain DMLL10 showed antibacterial activity against seven common foodborne pathogens, although bacteriocin genes were not identified from its genome. These results indicates that strain DMLL10 is a novel starter candidate with safety, enzyme activity, and bacteriocin activity. The complete genomic sequence of DMLL10 will contribute to our understanding of the genetic basis of probiotic properties and allow for assessment of the effectiveness of this strain as a starter or probiotic for use in the food industry.

• Toxicological Research
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• 제32권3호
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• pp.215-223
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• 2016

This study is to investigate the biological, biochemical and cytotoxic effects of puffer fish (Arothron stellatus) toxin extracts under in-vitro condition. Extracted toxins from various organs of puffer fish were purified by using active charcoal column, and Bio-gel-P2 column chromatography. The lethality of toxin was tested in crabs, which consists of neurotoxic compounds. The degree of the brine shrimp lethality assay was found directly proportional to the concentration of the toxin extracts, which was well supported by hemolytic assay. The experimental results suggested that the gonad was found higher toxins than the liver and muscles. The mortality rate of brine shrimp nauplii was increased with the raise of concentrations of toxin level. Among the different doses and time dependent cytotoxic effect of human cervical carcinoma (HeLa) cells were showed $4.0{\mu}g/mL$ of toxin, which was effectively inhibited cancer cell proliferation. HPLC and TLC analysis was revealed that the A. stellatus toxin contains tetrodotoxin (TTX), related compounds 4-epi TTX and anhydro-TTX. The present results suggested that the A. stellatus contain TTX as a major and anh-TTX as a minor toxin. It could be the potential candidate in the field of anticancer drug discovery against human cervical cancer cells. The present data is confirming that the puffer fish toxin as an interesting source of novel bioactive natural compounds with potent applications in pharmacology.

• 한국전산유체공학회지
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• 제20권2호
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• pp.88-95
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• 2015

Blood pump analysis process includes both mechanical and bio-mechanical aspects. Since a blood pump is a mechanical device, it has to be mechanically efficient. On the other hand, blood pumps function is sensitively related to the blood recirculation; hence, bio-factors such as hemolysis and thrombosis become important. This paper numerically investigates the mechanical and bio-mechanical performances of the Rotaflow in the extracorporeal membrane oxygenation(ECMO), Ventricular Assist Device(VAD), and full-load conditions. The operational conditions are defined as(400[mmHg], 5[L/min.]), (100[mmHg], 3[L/min.]), and (600[mmHg], 10[L/min.]) for ECMO, VAD, and full-load conditions, respectively. The results are presented and analyzed from the mechanical aspect via performance curves, and from bio-mechanical aspect via focusing on hemolytic characteristics. Regions of top and bottom cavities show recirculation in both ECMO and VAD condtions. In addition, Eulerian-based calculation of modified index of hemolysis(MIH) has been investigated. The results demonstrate that the VAD condition has the least risk of hemolysis among the others, while the full-load condition has the highest risk.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2818-2824
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• 2014

Trp residue is considered as one of the important constituents in antimicrobial peptides (AMPs) as it presence secured good activities in many cases. However, it is preferable to be changed because of their sensitivity towards light. We have synthesized the short Trp-rich AMP Pac-525 and its analogues to investigate the possibility of His(chx) as possible replacement analogue for Trp in AMPs. Based on the assay result of the antibacterial activity including anti-MRSA activity, His(chx) is considered as good candidate for the Trp replacement. Through these study, we found that His(chx) had several merits to design therapeutic antimicrobial agents compare to Trp in terms of i) increasing antibacterial activity without hemolytic activity, ii) successful in designing the short peptide (only four residues), iii) having anti-MRSA activity, iv) overcoming the light sensitivity. Furthermore, transmission electron microscopy (TEM) and dye leakage experiments suggested that P11 and P16 containing His(chx) kill bacteria via forming pore/ion channels on bacterial cell membranes.

• 대한영양사협회학술지
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• 제11권1호
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• pp.44-50
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• 2005

Natural products are increasingly appreciated as a lead for drug discovery and development. A number of investigators have studied various activities of natural products and have found that they have not only nutritional effects but also beneficial properties to cure various diseases and to maintain good health. Job's Tear(Yul-Moo) is a grass crop that have long been used in traditional medicine and a nourishing food. Job's Tear has been reported to exhibit anti-inflammatory, stomachic, antiallergic activity, and antispastic effects and has been used in China for the treatment of warts, rheumatism, and neuralgia although its mechanism remains unclear. Previous results in our laboratory demonstrated that the ethanol extract and water extract of Job's Tear exerted an immune regulatory function on mice cells in vitro. The present study was performed to investigate the ex vivo effect of Job's Tear on immune function. Seven to eight weeks old mices(Balb/c) were fed ad libitum on chow diet and water extract of Job's Tear were orally administrated every other day for two or four weeks at two different concentrations (50 and 500mg/kg B.W.). Proliferation of mice spenocytes and antibody production to sheep red blood cells(SRBC) using hemolytic plague forming cell assay were used to indicate the immune activity. Splenocytes proliferation of Job's Tear with mitogen stimulation such as Con A and LPS was enhanced at 50 mg/kg B.W. concentrations compared to those of control group. In case of antibody production to sheep red blood cells, the number of antibody- secreting cells was increased by administration of 50mg/kg B.W. concentration in mice immunized as a T-dependent antigen. From the present study, Job's Tear water extracts may be suggested to stimulate the mice immune response by enhancing the splenocytes proliferation and the number of plague forming cells.

• Applied Biological Chemistry
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• 제50권4호
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• pp.257-261
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• 2007

Pseudomonas tolaasii에 의해서 분비되는 펩티드 독소인 tolaasin은 재배버섯에 세균성 갈반병을 유발한다. Tolaasin의 독성은 적혈구를 파괴하는 용혈활성으로 평가된다. Tolaasin 펩티드는 C-말단부위에 두 개의 amine기를 갖고있어, 이 펩티드의 세포막 결합은 amine기의 전하상태에 따라 다를 수 있다. 이것을 확인하기 위하여 tolaasin을 적정하였을 때, 적정곡선은 pH 7.0에서 9.6 사이에서 적정이 되는 amine기가 있음을 보였다. Tolaasin에 의한 용혈활성의 pH 의존성을 조사하였을 때, 용혈활성은 알칼리 조건에서 증가함을 확인하였다. 따라서, pH 변화에 따른 tolaasin의 막결합 특성을 조사하기 위하여 적혈구를 tolaasin과 사전배양한 후, tolaasin을 포함하지 않은 완충액으로 씻어내고, 사전배양중 적혈구에 결합한 tolaasin의 용혈활성을 측정하였을 때, 활성은 pH 8 이상에서 크게 증가하였다. 이러한 결과는 tolaasin이 전하가 없거나 양전하량이 적은 상태에서 세포막에 잘 결합하여 세포독성이 커진다는 것을 의미한다.