• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.759-764
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• 2015

Antimicrobial peptides (AMPs) are one of the critical components in host innate immune responses to imbalanced and invading microbial pathogens. Although the antimicrobial activity and mechanism of action have been thoroughly investigated for decades, the exact biological properties of AMPs are still elusive. Most AMPs generally exert the antimicrobial effect by targeting the microbial membrane, such as barrel stave, toroidal, and carpet mechanisms. Thus, the mode of action in model membranes and the discrimination of AMPs to discrepant lipid compositions between mammalian cells and microbial pathogens (cell selectivity) have been studied intensively. However, the latest reports suggest that not only AMPs recently isolated but also well-known membrane-disruptive AMPs play a role in intracellular killing, such as apoptosis induction. In this mini-review, we will review some representative AMPs and their antimicrobial mechanisms and provide new insights into the dual mechanism of AMPs.

• Journal of Microbiology and Biotechnology
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• 제31권6호
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• pp.875-881
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• 2021

The mitochondrial targeting domain (MTD) of Noxa contributes to its mitochondrial localization and to apoptosis induction. As a peptide, MTD fused with octa-arginine (R8), a CPP, induces necrosis related to intracellular calcium influx and destruction of mitochondria and endoplasmic reticulum. We searched for homologs of MTD, and compared their cell killing capability when fused with R8. Three of the seven peptides triggered cell death with similar mechanisms. The comparative analysis of peptide sequences showed that four amino acid sites of MTD are critical in regulating necrosis, suggesting the potential to generate artificial, adjustable cytotoxic peptides, which could be effective medicines for many diseases. Thus, homologs functionality could hint to the functions of their belonging proteins.

• 한국응용곤충학회지
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• 제55권2호
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• pp.177-188
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• 2016

알파 프로테박테리아(${\alpha}-proteobacterium$)인 볼바키아(Wolbachia) 세균은 절지동물 세포내의 중요한 공생균 중의 하나이다. 그람 음성 세균인 이 공생균은 기주동물의 여러 생물적 과정에 관여하고 있으며, 현재 생물적 방제 수단으로 주목 받고 있다. 볼바키아는 기주 세포의 세포질에 서식하는 세균인데 암컷을 통하여 세대간 전염된다. 볼파키아의 감염 개체 밀도를 높이기 위해 기주의 생식방식을 조작하는 다양한 전략을 발달시켰다. 볼바키아 유전자형 계통은 볼바키아 표면 단백질(WSP)의 고변이영역 아미노산 서열과 복합좌위 서열 타이핑(Multilocus sequence typing, MLST)으로 결정된다. 상이한 유전계통 판별은 wsp, 16S rRNA, ftsZ, gltA, groEL 등 유전자 분자표지를 이용하게 된다.. 이 계통 볼바키아 세균과 그들의 우월한 표현형이 농업해충과 인간의 질병매개 곤충에 대한 방제 프로그램에서 이용 가능성이 고려되고 있다. 볼바키아 표현형들은 세포질불일치(cytoplasmic incompatibility, CI), 단성생식 유도(parthenogenesis induction, PI), 여성화(feminization, F), 수컷치사(male killing, MK) 등을 유발하는 것으로 알려져 있다. 기타 볼바키아 세균의 농업과 위생곤충 방제 프로그램에서 응용 방안을 고찰하였다.

• 대한한방부인과학회지
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• 제28권1호
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• pp.29-45
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• 2015

Objectives: The object of this study was to observe the in vitro antibacterial effects of Yeonkyokeumpae-jeon (YKKPJ) have been used for treating various gynecological diseases including mastitis in Korea, and individual six kinds of herbal composition aqueous extracts - Forsythiae Fructus (FF), Millettiae Caulis (MC), Lonicerae Flos (LF), Fritillaria Thunbergii Bulb (FT), Taraxci Herba (TH) and Prunellae Spica (PS) against E. coli. Methods: Antibacterial activities against E. coli of YKKPJ, FF, MC, LF, FT, TH and PS aqueous extracts were detected using standard agar microdilution methods. In addition, the effects on the bacterial growth curve were also monitored at MIC and $MIC{\times}2$ levels. The effects on the intracellular killing and bacterial invasion of individual test materials were also observed using Raw 264.7 and MCF-7. The results were compared with ciprofloxacin, a second generation of quinolone antibiotics in the present study. Results: MIC of YKKPJ, FF, MC, LF, FT, TH, PS aqueous extracts against E. coli were detected as $0.039{\pm}0.013mg/ml$, $0.064{\pm}0.033mg/ml$, $0.108{\pm}0.053mg/ml$, $0.078{\pm}0.027mg/ml$, $16.250{\pm}8.385mg/ml$, $15.625{\pm}9.375mg/ml$, $0.254{\pm}0.131mg/ml$, repectively. YKKPJ, FF, MC, LF, FT, TH, PS aqueous extracts showed antibacterial effects against to E. coli, except for FT and TH, which were showed negligible antibacterial effects, respectively. In addition, ciprofloxacin with YKKPJ, FF, MC, LF and PS aqueous extracts also showed marked dosage-dependent inhibition of bacterial growth, and favorable inhibitory effects on the both bacterial invasion and intracellular killing assays using MCF-7 and Raw 264.7 cells were detected in this experiment. Conclusions: The results obtained in this study suggest that traditional polyherbal formula YKKPJ aqueous extracts showed more favorable antibacterial activities as compared to individual six kinds of herbal composition aqueous extracts. The antibacterial effects of YKKPJ against E. coli considered as results of complicated synergic effects of their six kinds of herbal components rather than simple antibacterial effects of single herbal components. It means, YKKPJ aqueous extracts may show potent anti-infectious effects against E. coil for mastitis.

• IMMUNE NETWORK
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• 제11권5호
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• pp.268-280
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• 2011

Background: Dengue virus, which belongs to the Flavivirus genus of the Flaviviridae family, causes fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) with infection risk of 2.5 billion people worldwide. However, approved vaccines are still not available. Here, we explored the immune responses induced by alternating prime-boost vaccination using DNA vaccine, adenovirus, and vaccinia virus expressing E protein of dengue virus type 2 (DenV2). Methods: Following immunization with DNA vaccine (pDE), adenovirus (rAd-E), and/or vaccinia virus (VV-E) expressing E protein, E protein-specific IgG and its isotypes were determined by conventional ELISA. Intracellular CD154 and cytokine staining was used for enumerating CD4+ T cells specific for E protein. E protein-specific CD8+ T cell responses were evaluated by in vivo CTL killing activity and intracellular IFN-${\gamma}$ staining. Results: Among three constructs, VV-E induced the most potent IgG responses, Th1-type cytokine production by stimulated CD4+ T cells, and the CD8+ T cell response. Furthermore, when the three constructs were used for alternating prime-boost vaccination, the results revealed a different pattern of CD4+ and CD8+ T cell responses. i) Priming with VV-E induced higher E-specific IgG level but it was decreased rapidly. ii) Strong CD8+ T cell responses specific for E protein were induced when VV-E was used for the priming step, and such CD8+ T cell responses were significantly boosted with pDE. iii) Priming with rAd-E induced stronger CD4+ T cell responses which subsequently boosted with pDE to a greater extent than VV-E and rAd-E. Conclusion: These results indicate that priming with live viral vector vaccines could induce different patterns of E protein-specific CD4+ and CD8+ T cell responses which were significantly enhanced by booster vaccination with the DNA vaccine. Therefore, our observation will provide valuable information for the establishment of optimal prime-boost vaccination against DenV.

• International Journal of Oral Biology
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• 제34권1호
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• pp.43-48
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• 2009

Thrombin-induced platelet microbicidal protein (tPMP) is a small cationic peptide that exerts potent in vitro microbicidal activity against a broad spectrum of human pathogens, including Staphylococcus aureus and Streptococcus rattus BHT. Earlier evidence has suggested that tPMP targets and disrupts the bacterial membrane. However, it is not yet clear whether membrane disruption itself is sufficient to kill the bacteria or whether subsequent, presumably intracellular, events are also involved in this process. In this study, we investigated the microbicidal activity of rabbit tPMP toward S. rattus BHT cells in the presence or absence of a pretreatment with antibiotics that differ in their mechanisms of action. The streptocidal effects of tPMP on control cells (no antibiotic pretreatment) were rapid and concentration-dependent. Pretreatment of S. rattus BHT cells with either penicillin or amoxicillin (inhibitors of bacterial cell wall synthesis) significantly enhanced the anti-S. rattus BHT effects of tPMP compared with the effects against the respective control cells over most tPMP concentration ranges tested. On the other hand, pretreatment of S. rattus BHT cells with tetracycline or doxycycline (30S ribosomal subunit inhibitors) significantly decreased the streptocidal effects of tPMP over a wide peptide concentration range. Furthermore, pretreatment with rifampin (an inhibitor of DNA-dependent RNA polymerase) essentially blocked the killing of S. rattus BHT by tPMP at most concentrations compared with the respective control cells. These results suggest that tPMP exerts anti-S. rattus BHT activity through mechanisms involving both the cell membrane and intracellular targets.

• 대한수의학회지
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• 제32권1호
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• pp.117-125
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• 1992

Mycobacterium (M) bovis 를 인공감염시킨 개에 있어서 BCG의 전처치효과를 in vivo 및 in vitro에서 검토하였다. 개들은 BCG 전처치군, M bovis 단독처치군, 비감염대조군의 세군으로 나누었다. BCG는 M bovis 복강접종 3주일전에 0.2ml를 피내접종하였다. 결핵균 투여 4개월후에 전군을 도살하여 실험에 사용하였다. 도살시 모든 처치군에서 감염이 확인되었다. 병리조직학적으로 BCG전처치군의 폐장내에서는 경도의 macrophage의 침윤과 소상의 육아종 형성이 관찰되였으나 M bovis 단독처치군에 있어서는 보다 고도의 macrophage의 침윤, 중등도의 호중구의 침윤 및 중등도의 육아종의 형성이 확인되었다. 각 동물의 기관지폐포세정액을 분리하여 그 속의 총세포수와 각 세포의 분획을 검토하였다. 비감염 대조군의 기관지폐포세정액내의 총세포수는 두 처치군보다 훨씬 낮았으며 M bovis 단독처치군의 총세포수는 BCG 전처치군보다 1.8배 높았다. 이 세정액으로부터 폐포 macrophage를 분리배양하여 macrophage의 활성능과 결핵균의 증식능을 관찰하였다. BCG처치군은 M bovis 단독처치군에 비하여 높은 Fc receptor 활성(rosette 형성능, 탐식능)과 낮은 결핵균의 증식이 관찰되었다. 그러나 BCG의 전처치는 결핵균을 killing하지는 못하였다. 개에게 BCG를 전처치하면 폐내에 극소수의 결핵균이 지속적으로 잔존하지만 폐포 macrophage는 이미 항결핵성면역능을 지닌채로 계속 활성화된 상태로 존재하기 때문에 결핵에 대하여 예방효과를 갖는다고 사료된다.

• Parasites, Hosts and Diseases
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• 제47권2호
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• pp.109-115
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• 2009

This study investigated whether trinitroglycerine (TNG) as nitric oxide (NO) releasing agent had anti-leishmanial effects and mediated pathology in BALB/c mice infected with Leishmania major. Cutaneous leishmaniasis (CL), a zoonotic infection caused by leishmania protozoa is still one of the health problems in the world and in Iran. NO is involved in host immune responses against intracellular L. major, and leishmania killing by macrophages is mediated by this substance. Moreover, application of CL treatment with NO-donors has been recently indicated. In our study, TNG was used for its ability to increase NO and to modify CL infection in mice, in order to evaluate NO effects on lesion size and formation, parasite proliferation inside macrophages, amastigote visceralization in target organs, and NO induction in plasma and organ suspensions. Data obtained in this study indicated that TNG increased plasma and liver-NO, reduced lesion sizes, removed amastigotes from lesions, livers, spleens, and lymph nodes, declined proliferation of amastigotes, hepatomegaly, and increased survival rate. However, TNG reduced spleen-NO and had no significant effects on spelenomegaly. The results show that TNG therapy reduced leishmaniasis and pathology in association with raised NO levels. TNG had some antiparasitic activity by reduction of positive smears from lesions, livers, spleens, and lymph nodes, which could emphasize the role of TNG to inhibit visceralization of L. major in target organs.

• Journal of Acupuncture Research
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• 제17권3호
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• pp.176-187
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• 2000

Objectives : This study was purposed to investigate the antioxidative effects of Paeoniae radix aqua-acupuncture solution(PR) on culture liver cell system, lipid peroxidation and antioxidative enzyme activities in tert-butyl hydroperoxide(t-BHP) treatmented conditions. Methods : Cultured normal rat liver cell(Ac2F) were prepared and incubated with or without PR(at 2% volume in culture medium). After 16~18hr, cells placed in DMEM medium without serum, and then incubated with 1mM t-BHP for 2hr. Viable cells were detected by MTT assay, and the levels of lipid peroxide(LPO) were measured by TBA method. And catalase activity was measured as the decrease in hydrogen peroxide absorbance at 240nm on spectrophotometer using 30mM hydrogen peroxide. Superoxide dismutase(SOD) were assayed by recording the inhibition of nitro blue tetrazolium reduction with xanthine and xanthine oxidase. Glutathione peroxidase(GPX) activity was determined by the modified coupled assay developed by Paglia and Lawrence. The reaction was started by addition of 2.2mM hydrogen peroxide as substrate. The change in absorbance at 340nm was measured for 1min on spectrophotometer. Glutathione-S-transferase(GST) activity was assayed with CDNB as substrate and enzyme activity of GST towards the glutathione conjugation of CDNB. Results : Cell killing was significantly enhanced by addition of t-BHP compared to those of untreated group. PR pretreated cell resisted the toxic effects of t-BHP. LPO levels of t-BHP treatment group were significantly higher than other groups. This increased level was significandy reduced by PR pretreatment. The t-BHP treatment resulted in a decrease of catalase, GPX and GST activities. By contrast, PR pretreatment markedly increased compare to those of untreated groups. Conclusions : T-BHP which can produce intracellular free radical was used for inducer of the peroxidation of cellular lipids. PR protected the cell death induced by t-BHP and significantly increased cell viabiliry in the normal rat liver cell, and showed effective inhibition of lipid peroxidation, and elevations of catalase, GPX and GST activities. These results suggested that PR might play a protective role in lipid peroxidation by free radicals.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1401-1411
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• 2019

Mycobacterial cell walls comprise thick and diverse lipids and glycolipids that act as a permeability barrier to antibiotics or other chemical agents. The use of OH radicals from a non-thermal plasma jet (NTPJ) for the inactivation of mycobacteria in aqueous solution was adopted as a novel approach. Addition of water vapor in a nitrogen plasma jet generated OH radicals, which converted to hydrogen peroxide ($H_2O_2$) that inactivated non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis H37Rv. A stable plasma plume was obtained from a nitrogen plasma jet with 1.91 W of power, killing Escherichia coli and mycobacteria effectively, whereas addition of catalase decreased the effects of the former. Mycobacteria were more resistant than E. coli to NTPJ treatment. Plasma treatment enhanced intracellular ROS production and upregulation of genes related to ROS stress responses (thiolrelated oxidoreductases, such as SseA and DoxX, and ferric uptake regulator furA). Morphological changes of M. smegmatis and M. tuberculosis H37Rv were observed after 5 min treatment with $N_2+H_2O$ plasma, but not of pre-incubated sample with catalase. This finding indicates that the bactericidal efficacy of NTPJ is related to the toxicity of OH and $H_2O_2$ radicals in cells. Therefore, our study suggests that NTPJ treatment may effectively control pulmonary infections caused by M. tuberculosis and nontuberculous mycobacteria (NTM) such as M. avium or M. abscessus in water.