• 제목/요약/키워드: Time-kill

검색결과 167건 처리시간 0.029초

환경영향평가 협의 시 생태통로 조성을 위한 가이드라인 마련 (A Study on the Guidelines for Creating Wildlife Crossing through Environmental Impact Assessment)

  • 박용수;심윤진
    • 환경영향평가
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    • 제28권3호
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    • pp.287-298
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    • 2019
  • 본 연구는 "환경영향평가 협의 시 생물이동성 제고를 위한 법 제도적 고찰에 관한 연구"의 후속연구로 환경영향평가 협의를 통하여 조성된 대부분의 생태통로가 원목적과 부합하지 않게 조성되어 야생동물 교통사고를 저감하지 못하는 문제점을 개선하고자 수행하였다. 단절된 생태계의 연결성을 회복하기 위한 대안으로 환경영향평가 시 제시한 생태통로가 실질적인 역할을 할 수 있도록 각 단계별 고려사항을 제시하였다. 따라서 본 연구에서는 환경영향평가 협의 단계를 계획, 설계, 시공, 모니터링, 유지 관리 등 5단계로 구분하여 실무담당자가 각 단계별로 검토해야하는 구체적인 항목을 제시하였다. 이로 인하여 원목적과 부합하지 않게 조성되어 야생동물에게 외면당하는 생태통로 조성을 막아 개발 사업으로 인한 서식지 단절을 최소화하고 생물다양성을 향상시킬 수 있도록 하고자 하였다.

Identification of duck liver-expressed antimicrobial peptide 2 and characterization of its bactericidal activity

  • Hong, Yeojin;Truong, Anh Duc;Lee, Janggeun;Lee, Kyungbaek;Kim, Geun-Bae;Heo, Kang-Nyeong;Lillehoj, Hyun S.;Hong, Yeong Ho
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권7호
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    • pp.1052-1061
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    • 2019
  • Objective: This study was conducted to identify duck liver-expressed antimicrobial peptide 2 (LEAP-2) and demonstrate its antimicrobial activity against various pathogens. Methods: Tissue samples were collected from 6 to 8-week-old Pekin ducks (Anas platyrhynchos domesticus), total RNA was extracted, and cDNA was synthesized. To confirm the duck LEAP-2 transcript expression levels, quantitative real-time polymerase chain reaction was conducted. Two kinds of peptides (a linear peptide and a disulfide-type peptide) were synthesized to compare the antimicrobial activity. Then, antimicrobial activity assay and fluorescence microscopic analysis were conducted to demonstrate duck LEAP-2 bactericidal activity. Results: The duck LEAP-2 peptide sequence showed high identity with those of other avian species (>85%), as well as more than 55% of identity with mammalian sequences. LEAP-2 mRNA was highly expressed in the liver with duodenum next, and then followed by lung, spleen, bursa and jejunum and was the lowest in the muscle. Both of LEAP-2 peptides efficiently killed bacteria, although the disulfide-type LEAP-2 showed more powerful bactericidal activity. Also, gram-positive bacteria was more susceptible to duck LEAP-2 than gram-negative bacteria. Using microscopy, we confirmed that LEAP-2 peptides could kill bacteria by disrupting the bacterial cell envelope. Conclusion: Duck LEAP-2 showed its antimicrobial activity against both gram-positive and gram-negative bacteria. Disulfide bonds were important for the powerful killing effect by disrupting the bacterial cell envelope. Therefore, duck LEAP-2 can be used for effective antibiotics alternatives.

Ginsenoside Rg3 reduces the adhesion, invasion, and intracellular survival of Salmonella enterica serovar Typhimurium

  • Mechesso, Abraham F.;Quah, Yixian;Park, Seung-Chun
    • Journal of Ginseng Research
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    • 제45권1호
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    • pp.75-85
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    • 2021
  • Background: Invasive infections due to foodborne pathogens, including Salmonella enterica serovar Typhimurium, are prevalent and life-threatening. This study aimed to evaluate the effects of ginsenoside Rg3 (Rg3) on the adhesion, invasion, and intracellular survival of S. Typhimurium. Methods: The impacts of Rg3 on bacterial growth and host cell viability were determined using the time kill and the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assays, respectively. Gentamicin assay and confocal microscopic examination were undertaken to determine the effects of Rg3 on the adhesive and invasive abilities of S. Typhimurium to Caco-2 and RAW 264.7 cells. Quantitative reverse transcription polymerase chain reaction was performed to assess the expression of genes correlated with the adhesion, invasion, and virulence of S. Typhimurium. Results: Subinhibitory concentrations of Rg3 significantly reduced (p < 0.05) the adhesion, invasion, and intracellular survival of S. Typhimurium. Rg3 considerably reduced (p < 0.05) the bacterial motility as well as the release of nitrite from infected macrophages in a concentration-dependent manner. The expression of genes related to the adhesion, invasion, quorum sensing, and virulence of S. Typhimurium including cheY, hilA, OmpD, PrgK, rsgE, SdiA, and SipB was significantly reduced after Rg3 treatment. Besides, the compound downregulated rac-1 and Cdc-42 that are essential for actin remodeling and membrane ruffling, thereby facilitating Salmonella entry into host cells. This report is the first to describe the effects of Rg3 on "trigger" entry mechanism and intracellular survival S. Typhimurium. Conclusion: Rg3 could be considered as a supplement agent to prevent S. Typhimurium infection.

Methicillin resistant staphylococcus aureus에 대한 지유산의 항균활성 (Antibacterial Activity of JiYu-san Against Methicillin-resistant Staphylococcus aureus)

  • 황해;강옥화;권동렬
    • 생약학회지
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    • 제53권2호
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    • pp.87-95
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    • 2022
  • Methicillin resistance Staphylococcus aureus (MRSA) is a gram-positive bacterium, the most commonly isolated bacterial human pathogen. JiYu-san is one of the natural products used to treat diseases in the folk recipe. In this study, we investigated the antimicrobial activity of EtOH 70% extracts of JiYu-san (JYS) against MRSA. The antibacterial activity of JYS against MRSA strain was evaluated using minimum inhibitory concentration (MIC), checkerboard dilution test, and time-kill assay. The effect of JYS on the immune mechanism of MRSA was confirmed through cell membrane permeability tests and energy metabolism tests, and the antibacterial activity mechanism was performed using qRT-PCR and western blot. As a result, in the antibacterial test of JYS, the MIC was measured to be 1.9~1000 ㎍/mL, and synergistic or showed a partial synergistic effect. In addition, JYS showed antibacterial activity in a combination test with DCCD or TX-100. In a study on the mechanism of action of antibacterial activity, it was found that JYS suppressed MRSA resistance genes and proteins. These results suggest that JYS has antibacterial activity and provides great potential as a natural antibiotic by modulating the immune mechanism against MRSA.

Restoring Ampicillin Sensitivity in Multidrug-Resistant Escherichia coli Following Treatment in Combination with Coffee Pulp Extracts

  • Anchalee Rawangkan;Atchariya Yosboonruang;Anong Kiddee;Achiraya Siriphap;Grissana Pook-In;Ratsada Praphasawat;Surasak Saokaew;Acharaporn Duangjai
    • Journal of Microbiology and Biotechnology
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    • 제33권9호
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    • pp.1179-1188
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    • 2023
  • Escherichia coli, particularly multidrug-resistant (MDR) strains, is a serious cause of healthcare-associated infections. Development of novel antimicrobial agents or restoration of drug efficiency is required to treat MDR bacteria, and the use of natural products to solve this problem is promising. We investigated the antimicrobial activity of dried green coffee (DGC) beans, coffee pulp (CP), and arabica leaf (AL) crude extracts against 28 isolated MDR E. coli strains and restoration of ampicillin (AMP) efficiency with a combination test. DGC, CP, and AL extracts were effective against all 28 strains, with a minimum inhibitory concentration (MIC) of 12.5-50 mg/ml and minimum bactericidal concentration of 25-100 mg/ml. The CP-AMP combination was more effective than CP or AMP alone, with a fractional inhibitory concentration index value of 0.01. In the combination, the MIC of CP was 0.2 mg/ml (compared to 25 mg/ml of CP alone) and that of AMP was 0.1 mg/ml (compared to 50 mg/ml of AMP alone), or a 125-fold and 500-fold reduction, respectively, against 13-drug resistant MDR E. coli strains. Time-kill kinetics showed that the bactericidal effect of the CP-AMP combination occurred within 3 h through disruption of membrane permeability and biofilm eradication, as verified by scanning electron microscopy. This is the first report indicating that CP-AMP combination therapy could be employed to treat MDR E. coli by repurposing AMP.

항균마감재료와 병원 내 적용 부위 고찰 - 항생제 내성균을 중심으로 (A study on Antibacterial Finishing Materials and Application Areas in the Hospital - Focused on Antibiotic-resistant Bacteria)

  • 권순정;박용현
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제30권2호
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    • pp.15-22
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    • 2024
  • Purpose: In general, cross-infection caused by bacteria occurs more in hospitals than in local communities. In most cases, infectious diseases spread through contact transmission (direct contact, indirect contact). This study tries to examine which places are most likely to detect infections bacteria and what materials should be used to effectively suppress the spread of infectious bacteria. Methods: Domestic and international literature have been reviewed to determine which bacteria are common and spread in which places. At the same time, antibacterial experiments for several finishing materials are performed to determine the survival period of bacteria for each material. The experiment is conducted mainly on antibiotic-resistant bacteria (MRSA, CRE, etc.) that have a high mortality rate and are very contagious. Results: MRSA has a high incidence in many hospital departments with surgery or immunocompromised patients, such as the elderly, organ transplant patients, and hemodialysis patients. There are experimental results that MRSA dies early in ceramics or silk wallpaper. CRE has a high incidence in hospital departments where there are many patients who are prone to bacteria entering the body directly, such as ventilator patients or critically ill patients with surgical wounds. There are experimental results that CRE dies early in silk wallpaper. In addition, bacteria die on the surface for a variety of reasons. Most MRSA and CRE develop in patients with impaired immunity or surgery, and rapidly die in copper or materials with antibacterial properties. Implications: If finishing materials surface with the ability to kill specific bacteria is used in the place where a large number of specific bacteria are detected, the spread of infectious diseases can be effectively controlled.

원산지별 감초추출물의 추출 조건별 항균활성 (Antimicrobial Activities of Licorice Extracts from Various Countries of Origin according to Extraction Conditions)

  • 배정윤;장하나;하지훈;박종호;박진오;박수남
    • 한국미생물·생명공학회지
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    • 제42권4호
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    • pp.361-366
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    • 2014
  • 본 연구에서는 다양한 추출조건에서 원산지별 감초(한국은 제천감초, 우즈베키스탄산, 중국산) 추출물의 피부 상재균에 대한 항균활성을 확인하였다. 원산지별 감초추출물의 추출조건은 추출용매(30% EtOH, 85% EtOH), 온도($40^{\circ}C$, $60^{\circ}C$), 시간(6 h, 12 h)을 조절하여 총 8군으로 설정하였다. 피부 상재균에 대한 항균활성은 disc diffusion assay, broth macrodilution assay 및 kill time curve assay에 의해 평가되었다. 각각의 조건별 추출물들에 대하여 disc diffusion assay에 의해 각 원산지별 항균활성을 확인한 후, 가장 우수한 항균활성을 보인 추출 조건을 선정하였다. 한국산 감초추출물(85% EtOH, $40^{\circ}C$, 12 h)이 가장 우수한 항균활성을 보였으며, 특히 P. acnes에 대하여 2.5 mg/disc에서 19 mm을 저해하였다. 최소저해농도(MIC)와 최소사멸농도(MBC)는 액체 희석법을 이용하였으며, 원산지별 감초추출물의 MIC와 MBC는 한국산 감초추출물에서 각각 $156{\mu}g/ml$$1,250{\mu}g/ml$로 우즈베키스탄 감초추출물($625{\mu}g/ml$$2,500{\mu}g/ml$)과 중국산 감초추출물($625{\mu}g/ml$$5,000{\mu}g/ml$)보다 가장 우수한 항균 활성을 나타내었다. 이상의 결과들을 통하여 다양한 추출조건에서 추출한 원산지별 감초추출물 중에서 가장 우수한 항균활성을 나타내는 최적의 조건과 원산지가 F군(85% EtOH, $40^{\circ}C$, 12 h)에서 추출한 한국산 감초임을 확인했다. 이는 현재 사용되는 합성 방부제를 대신할 천연방부제인 화장품 원료로서 응용 가능성이 있음을 시사한다.

Assembly processes of moss and lichen community with snow melting at the coastal region of the Barton Peninsula, maritime Antarctic

  • Kim, Seok Cheol;Kim, Jun Seok;Hong, Bo Ram;Hong, Soon Gyu;Kim, Ji Hee;Lee, Kyu Song
    • Journal of Ecology and Environment
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    • 제40권1호
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    • pp.55-65
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    • 2016
  • Background: In this article, it was analyzed how snow melting affects the assembly of lichen and moss communities in a small area of the coastal region of Barton Peninsula, which is in maritime Antarctic. In the small area, even though there is a huge gap of difference of the environment between the snow-filled area and snow-melt one, the latter did not have distinctive environmental gradients. Results: Depending on the snow melting time, coverage and species diversity of lichens and mosses tend to increase remarkably. For species with significant changes depending on the snow-covered period, there are Andreaea regularis, crustose lichens, Placopsis contortuplicata, Usnea aurantiaco-atra, and snow algae. In this area, the process of vegetation assembly process has shown the directional development in the order of snow algae${\rightarrow}$crustose, lichen sub-formation${\rightarrow}$fruticose lichen, moss cushion sub-formation (Andreaea sociation)${\rightarrow}$fruticose lichen, and moss cushion sub-formation (Usnea sociation), according to the order of snow melting. These directional development stages are shown in gradual change in small area with the snow melting phenomena. However, in the snow-free area, where water is sufficiently supplied, it is expected that moss carpet sub-formation (Sanionia sociation) will be developed. Vegetation development in the small area with the snow melting phenomena, depending on differences of resistance on snow kill and moisture settled by species in according to the time of snow melting, tolerance model to form community is followed. Conclusions: The research results explain the development of vegetation in the Antarctic tundra and its spatial distribution according to the period for growth of lichens and mosses in the summer time by differences of snow melting in the small area. In the future, if research for the community development process in a large scale will be done, it will be helpful to figure out temporal and spatial dynamic of vegetation in the Antarctic tundra where snow and glaciers melt rapidly due to climatic warming.

Roles of p53 and Caspases in Induction of Apoptosis in MCF-7 Breast Cancer Cells Treated with a Methanolic Extract of Nigella Sativa Seeds

  • Alhazmi, Mohammed I.;Hasan, Tarique N.;Shafi, Gowhar;Al-Assaf, Abdullah H.;Alfawaz, Mohammed A.;Alshatwi, Ali A.
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권22호
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    • pp.9655-9660
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    • 2014
  • Background: Nigella Sativa (NS) is an herb from the Ranunculaceae family that exhibits numerous medicinal properties and has been used as important constituent of many complementary and alternative medicines (CAMs). The ability of NS to kill cancer cells such as PC3, HeLa and hepatoma cells is well established. However, our understanding of the mode of death caused by NS remains nebulous. The objective of this study was to gain further insight into the mode and mechanism of death caused by NS in breast cancer MCF-7 cells. Materials and Methods: Human breast cancer cells (MCF-7) were treated with a methanolic extract of NS, and a dose- and time-dependent study was performed. The $IC_{50}$ was calculated using a Cell Titer $Blue^{(R)}$ viability assay assay, and evidence for DNA fragmentation was obtained by fluorescence microscopy TUNEL assay. Gene expression was also profiled for a number of apoptosis-related genes (Caspase-3, -8, -9 and p53 genes) through qPCR. Results: The $IC_{50}$ of MCF-7 cells was $62.8{\mu}L/mL$. When MCF-7 cells were exposed to $50{\mu}L/mL$ and $100{\mu}L/mL$ NS for 24h, 48h and 72h, microscopic examination (TUNEL assay) revealed a dose- and time-dependent increase in apoptosis. Similarly, the expression of the Caspase-3, -8, -9 and p53 genes increased significantly according to the dose and time. Conclusions: NS induced apoptosis in MCF-7 cells through both the p53 and caspase pathways. NS could potentially represent an alternative source of medicine for breast cancer therapy.

중국군의 해양작전능력과 한국군의 과제 (PRC Maritime Operational Capability and the Task for the ROK Military)

  • 김민석
    • Strategy21
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    • 통권33호
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    • pp.65-112
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    • 2014
  • Recent trends show that the PRC has stepped aside its "army-centered approach" and placed greater emphasis on its Navy and Air Force for a wider range of operations, thereby reducing its ground force and harnessing its economic power and military technology into naval development. A quantitative growth of the PLA Navy itself is no surprise as this is not a recent phenomenon. Now is the time to pay closer attention to the level of PRC naval force's performance and the extent of its warfighting capacity in the maritime domain. It is also worth asking what China can do with its widening naval power foundation. In short, it is time to delve into several possible scenarios I which the PRC poses a real threat. With this in mind, in Section Two the paper seeks to observe the construction progress of PRC's naval power and its future prospects up to the year 2020, and categorize time frame according to its major force improvement trends. By analyzing qualitative improvements made over time, such as the scale of investment and the number of ships compared to increase in displacement (tonnage), this paper attempts to identify salient features in the construction of naval power. Chapter Three sets out performance evaluation on each type of PRC naval ships as well as capabilities of the Navy, Air Force, the Second Artillery (i.e., strategic missile forces) and satellites that could support maritime warfare. Finall, the concluding chapter estimates the PRC's maritime warfighting capability as anticipated in respective conflict scenarios, and considers its impact on the Korean Peninsula and proposes the directions ROK should steer in response. First of all, since the 1980s the PRC navy has undergone transitions as the focus of its military strategic outlook shifted from ground warfare to maritime warfare, and within 30 years of its effort to construct naval power while greatly reducing the size of its ground forces, the PRC has succeeded in building its naval power next to the U.S.'s in the world in terms of number, with acquisition of an aircraft carrier, Chinese-version of the Aegis, submarines and so on. The PRC also enjoys great potentials to qualitatively develop its forces such as indigenous aircraft carriers, next-generation strategic submarines, next-generation destroyers and so forth, which is possible because the PRC has accumulated its independent production capabilities in the process of its 30-year-long efforts. Secondly, one could argue that ROK still has its chances of coping with the PRC in naval power since, despite its continuous efforts, many estimate that the PRC naval force is roughly ten or more years behind that of superpowers such as the U.S., on areas including radar detection capability, EW capability, C4I and data-link systems, doctrines on force employment as well as tactics, and such gap cannot be easily overcome. The most probable scenarios involving the PRC in sea areas surrounding the Korean Peninsula are: first, upon the outbreak of war in the peninsula, the PRC may pursue military intervention through sea, thereby undermining efforts of the ROK-U.S. combined operations; second, ROK-PRC or PRC-Japan conflicts over maritime jurisdiction or ownership over the Senkaku/Diaoyu islands could inflict damage to ROK territorial sovereignty or economic gains. The PRC would likely attempt to resolve the conflict employing blitzkrieg tactics before U.S. forces arrive on the scene, while at the same time delaying and denying access of the incoming U.S. forces. If this proves unattainable, the PRC could take a course of action adopting "long-term attrition warfare," thus weakening its enemy's sustainability. All in all, thiss paper makes three proposals on how the ROK should respond. First, modern warfare as well as the emergent future warfare demonstrates that the center stage of battle is no longer the domestic territory, but rather further away into the sea and space. In this respect, the ROKN should take advantage of the distinct feature of battle space on the peninsula, which is surrounded by the seas, and obtain capabilities to intercept more than 50 percent of the enemy's ballistic missiles, including those of North Korea. In tandem with this capacity, employment of a large scale of UAV/F Carrier for Kill Chain operations should enhance effectiveness. This is because conditions are more favorable to defend from sea, on matters concerning accuracy rates against enemy targets, minimized threat of friendly damage, and cost effectiveness. Second, to maintain readiness for a North Korean crisis where timely deployment of US forces is not possible, the ROKN ought to obtain capabilities to hold the enemy attack at bay while deterring PRC naval intervention. It is also argued that ROKN should strengthen its power so as to protect national interests in the seas surrounding the peninsula without support from the USN, should ROK-PRC or ROK-Japan conflict arise concerning maritime jurisprudence. Third, the ROK should fortify infrastructures for independent construction of naval power and expand its R&D efforts, and for this purpose, the ROK should make the most of the advantages stemming from the ROK-U.S. alliance inducing active support from the United States. The rationale behind this argument is that while it is strategically effective to rely on alliance or jump on the bandwagon, the ultimate goal is always to acquire an independent response capability as much as possible.