• 농업과학연구
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• 제28권2호
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• pp.92-98
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• 2001

락토페리신은 다양한 생리활성을 나타내는 락토페린(약 80kD)에서 유래된 항균성펩타이드 분획물(5kD)이다. 마우스HC11유선상피세포에서 인체 락토페리신의 발현은 bovine beta-casein을 promotor로 하고 인체 락토페리신 cDNA를 삽입하여 제작한 pBL1-cin발현벡타를 이용하였다. 이 발현벡타를 이용하여 인체 락토페리신 발현여부를 RT-PCR, northern blot, dot blot분석을 통하여 확인하였다. pBL1-cin 발현백타를 HC11세포에 transfection 하여 얻은 RNA를 이용하여 RT-PCR를 한 결과 150bp의 크기로 확인되었고 Northern blot 분석결과는 약 2.3 kb의 크기로 확인되었다. 인체 락토페린 polyclonal항체를 이용하여 dot blot한 결과 인체 락토페리신이 분비됨을 확인하였다.

• 한국자기공명학회논문지
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• 제15권1호
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• pp.1-13
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• 2011

9Pbw2 is a 9-mer analog of protaetiamycine derived from the larvae of the beetle Protaetia brevitarsis. Previously, we designed four 9-mer peptide analogues to optimize the balance between the hydrophobicity and cationicity of the peptides and to increase bacterial cell selectivity. Among them, 9Pbw2 has high antibacterial activity without cytotoxicity. The results obtained in previous study suggest that the bactericidal action of 9Pbw2 may be attributed to the inhibition of the functions of intracellular components after penetration of the bacterial cell membrane. In order to understand structure-activity relationships, we determined the three-dimensional structure of 9Pbw2 in 200 mM DPC micelle by NMR spectroscopy. 9Pbw2 has one hydrophobic turn helix from $Trp^3$ to $Arg^8$ and positively charged residues at the N- and C-terminus. This result suggested that positively charged residues from position at the C-terminus in 9Pbw2 may be important for the primary binding to the negatively charged phospholipid head groups in bacterial cell membranes and hydrophobic residues in the middle portion face toward the acyl chains of the hydrophobic lipid in the bacterial cell membrane.

• Journal of Microbiology and Biotechnology
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• 제18권11호
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• pp.1836-1840
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• 2008

Bacteriocins are antimicrobial peptides that are produced by bacteria and toxic to bacterial strains closely related to the producer strain. It has previously been reported that Bacillus thuringiensis strain NEB17 and Bacillus thuringiensis subsp. kurstaki BUPM4 produce the bacteriocins thuricin 17 (3,162 Da) and bacthuricin F4 (3,160.05 Da), respectively. Here, we demonstrate that these bacteriocins have functional similarities and show a similar spectrum of antimicrobial activities against indicator strains. We also studied the effects of sterilization methods on the recovery and biological activities of these bacteriocins. They were completely degraded by autoclaving and the two were similarly affected by the tested filter membranes. Polyvinylidene fluoride (PVDF), polyestersulfone (PES), and cellulose acetate (CA) are suitable for filter sterilization of these bacteriocins. The two bacteriocins were stable across a range of storage conditions. These data will facilitate their utilization in food preservation or agricultural applications.

• Fisheries and Aquatic Sciences
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• 제26권4호
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• pp.241-255
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• 2023

The robust development of frog farming offered high economic benefits but created a large waste residue of frog bones and skin that received little attention. Over the years, inedible by-products have often been processed into biomolecules of potential value and environmental benefits, such as collagen, gelatin, and bioactive peptides. An overview of bioactive compounds on frog skins from various countries indicated that brevinin was the most abundant biological peptide found in frog skin. Other remaining compounds also possessed their highlighted activities, including antibacterial, stimulating insulin release and gastric hormone release, anti-cancer, and neuroregulatory. Notably, various components have been analyzed in the structure and sequence to give meaningful insight into clustering components related to their biological activity. This review may create a source of raw materials for the developmental research of by-products from frog skin and concomitantly reduce environmental pollution.

• Journal of Microbiology and Biotechnology
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• 제34권6호
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• pp.1189-1196
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• 2024

Bacterial resistance to commonly used antibiotics is one of the major challenges to be solved today. Bacteriophage endolysins (Lysins) have become a hot research topic as a new class of antibacterial agents. They have promising applications in bacterial infection prevention and control in multiple fields, such as livestock and poultry farming, food safety, clinical medicine and pathogen detection. However, many phage endolysins display low bactericidal activities, short half-life and narrow lytic spectrums. Therefore, some methods have been used to improve the enzyme properties (bactericidal activity, lysis spectrum, stability and targeting the substrate, etc) of bacteriophage endolysins, including deletion or addition of domains, DNA mutagenesis, chimerization of domains, fusion to the membrane-penetrating peptides, fusion with domains targeting outer membrane transport systems, encapsulation, the usage of outer membrane permeabilizers. In this review, research progress on the strategies for improving their enzyme properties are systematically presented, with a view to provide references for the development of lysins with excellent performances.

• 한국식품영양과학회지
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• 제35권2호
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• pp.127-131
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• 2006

효소에 의한 옥수수 단백가수분해물의 천연항균제로서의 이용가능성을 조사하기 위하여 zein 단백질에 단백 가수분해 효소를 작용시켜 얻어진 가수분해물의 항균활성을 측정하고 membrane filter로 한외 여과하여 항균활성이 가장 높은 분획을 HPLC로 분취한 후 항균활성을 측정하고 MIC, 각종 세균에 대한 생육저해농도를 측정하여 다음과 같은 결과를 얻었다. Zein 단백질에 6종의 단백분해효소를 작용시켜 제조한 가수분해물 중 pepsin으로 작용시킨 것이 항균활성이 가장높았다. Membrane filter에 의하여 여과한가수분해물의 항균활성은 M.W. $10,000\~30,000$에서 가장 높았으며 $121^{\circ}C$에서 10분간 처리하여도 항균활성에 변화가 없는 열안정성이 매우 높았고 MIC는 2.5 mg/mL이었다. HPLC로 분리한 항균성 peptide의 N-말단 아미노산 조성은 leucine, glutamic acid, proline, phenylalanine, aspartic acid, argenine 순이었다. 분자량 $10,000\~30,000$의 가수분해 동결건조물을 3 mg/mL 농도로 nutrient broth 배지에 첨가하고 $37^{\circ}C$에서 배양하였을 때 크게 생육이 저해되었다.

• 농업과학연구
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• 제43권1호
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• pp.14-20
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• 2016

One of the most powerful health management practices is the use of antibiotics, but their use is being restricted because of health safety issues. The swine industry has been looking for various alternatives to antibiotics and increasingly considers the use of dietary factors like feed ingredients, feed additives, feed formulation practices, or feeding methods, instead of using antibiotics to improve pig health and performance. Among other alternatives to antibiotics, spray-dried plasma may be a candidate. Spray-dried plasma is a blood product that provides bioavailable nutrients and physiologically active components such as immunoglobulins, glycoproteins, growth factors, peptides, etc. It is an excellent protein source with balanced and highly digestible amino acids. Several beneficial physiological activities depend on components of spray-dried plasma, such as immune competence (antibacterial activity), modulation of microbiota and/or immune system, integrity of intestinal barrier function, etc. These beneficial effects can contribute to improvement of pig performance and health by modulation of microbiota in the digestive tract and/or immune system. Therefore, it is suggested that spray-dried plasma has great potential as an antibiotics alternative.

• Biomolecules & Therapeutics
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• 제26권3호
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• pp.242-254
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• 2018

Defensins are antimicrobial peptides that participate in the innate immunity of hosts. Humans constitutively and/or inducibly express ${\alpha}$- and ${\beta}$-defensins, which are known for their antiviral and antibacterial activities. This review describes the application of human defensins. We discuss the extant experimental results, limited though they are, to consider the potential applicability of human defensins as antiviral agents. Given their antiviral effects, we propose that basic research be conducted on human defensins that focuses on RNA viruses, such as human immunodeficiency virus (HIV), influenza A virus (IAV), respiratory syncytial virus (RSV), and dengue virus (DENV), which are considered serious human pathogens but have posed huge challenges for vaccine development for different reasons. Concerning the prophylactic and therapeutic applications of defensins, we then discuss the applicability of human defensins as antivirals that has been demonstrated in reports using animal models. Finally, we discuss the potential adjuvant-like activity of human defensins and propose an exploration of the 'defensin vaccine' concept to prime the body with a controlled supply of human defensins. In sum, we suggest a conceptual framework to achieve the practical application of human defensins to combat viral infections.

• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.522-533
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• 2014

Bionanotechnology has revolutionized nanomaterial synthesis by providing a green synthetic platform using biological systems. Among such biological systems, microalgae have tremendous potential to take up metal ions and produce nanoparticles by a detoxification process. The present study explores the intracellular and extracellular biogenic syntheses of silver nanoparticles (SNPs) using the unicellular green microalga Scenedesmus sp. Biosynthesized SNPs were characterized by AAS, UV-Vis spectroscopy, TEM, XRD, FTIR, DLS, and TGA studies and finally checked for antibacterial activity. Intracellular nanoparticle biosynthesis was initiated by a high rate of $Ag^+$ ion accumulation in the microalgal biomass and subsequent formation of spherical crystalline SNPs (average size, 15-20 nm) due to the biochemical reduction of $Ag^+$ ions. The synthesized nanoparticles were intracellular, as confirmed by the UV-Vis spectra of the outside medium. Furthermore, extracellular synthesis using boiled extract showed the formation of well scattered, highly stable, spherical SNPs with an average size of 5-10 nm. The size and morphology of the nanoparticles were confirmed by TEM. The crystalline nature of the SNPs was evident from the diffraction peaks of XRD and bright circular ring pattern of SAED. FTIR and UV-Vis spectra showed that biomolecules, proteins and peptides, are mainly responsible for the formation and stabilization of SNPs. Furthermore, the synthesized nanoparticles exhibited high antimicrobial activity against pathogenic gram-negative and gram-positive bacteria. Use of such a microalgal system provides a simple, cost-effective alternative template for the biosynthesis of nanomaterials in a large-scale system that could be of great use in biomedical applications.

• 동의생리병리학회지
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• 제29권2호
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• pp.189-194
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• 2015

Streptococcus mutans (S. mutans) is one of the most important bacteria in the formation of dental plaque and dental caries. S. mutans adheres to an acquired pellicle formed on the tooth surface, and aggregates with many oral bacteria, and initiates plaque formation by synthesizing glucan from sucrose, which is catalyzed by glucosyltransferases. S. mutans metabolizes the dietary sugar to the organic acids. The organic acids demineralize tooth surface and result in dental caries. Galla Chinensis have been traditionally used for stopping bleeding of gingiva, removing edema and halitosis, drainage, fixing the teeth and as an antiphlogistic agent. In previous reports, antibacterial effects of Galla Chinensis have been investigated whereas anti-cariogenic effects is still not examined enough. Therefore we tested effects of ethanol extracts of Galla Chinensis on the cariogenic properties such as the growth, acid production, adhesion, and insoluble glucan synthesis of S. mutans. In the result, ethanol extracts of Galla Chinensis showed the inhibition of S. mutans growth and organic acids production over 0.031 mg/ml concentrations. The adhesion of S. mutans to Saliva-coated Hydroxyapatite beads S-HAs has decreased with the increase of concentration of ethanol extracts of Galla Chinensis. And it seems to have adhesion inhibitory effect in concentration of over 0.25 mg/ml. It gives us the result that Galla Chinensis have anti-caries effects. But ethanol extract of Galla Chinensis didn't have inhibitory effect on insoluble glucan synthesis. Preliminary phytochemical analysis of the ethanol extract of Galla Chinensis showed strong phenolic compounds, medium steroids & terpenoids and glycosides, and weak organic acids and peptides. These results suggest that the ethanol extracts of Galla Chinensis may have anti-cariogenic properties, which may be able to be related with strong phenolic compounds.