BmCecB1 are antimicrobial peptides from Bombyx mori and belongs to cecropin family. Antimicrobial peptides are important components of the innate immune systems in all living organism. This peptide has antibacterial activity against several Gram-positive and Gram-negative bacteria. To produce the BmCecB1 antimicrobial peptide, we constructed transgenic silkworm that expressed BmCecB1 gene under the control BmA3 promoter using piggyBac vector. The use of the 3xP3-driven EGFP cDNA as a marker allowed us to rapidly distinguish transgenic silkworm. Mixtures of the donor vector and helper vector were micro-injected into 600 eggs of bivoltin silkworms, Baegokjam. In total, 49 larvae (G0) were hatched and allowed to develop into moths. The resulting G1 generation consisted of 22 broods, and we selected 2 broods containing at least 1 EGFP-positive embryo. The rate of successful transgenesis for the G1 broods was 11%. We identified 9 EGFP-positive G1 moths and these were backcrossed with wild-type moths. With the aim of identifying a BmCecB1 as antimicrobial peptide, we investigated the Radical diffusion Assay (RDA) and then demonstrated that BmCecB1 possesses high antibacterial activities against Gram-negative bacteria.

Immune-inducible antimicrobial peptides were produced using transgenic silkworms that expressed Rel family transcription factor, truncated BmRelish1 (BmRelish1t) genes under the control of the BmA3 promoter using the piggyBac vector. BmRelish1t gene contains all domains of Bmrelish: a Rel homolog domain (RHD), nuclear localization signal (NLS), acidic and hydrophobic amino acids (AHAA) rich region except the Ankyrin repeat domain (ANK) and the death domain (DD). (1:1) Mixtures of the donor vector (pG-3xP3EGFP-BmA3BmRelish1t) and helper vector were micro-injected into 1,800 eggs of bivoltin silkworms, Baegokjam and EGFP-induced fluorescence was observed for 25 broods of transgenic silkworms under a florescence stereomicroscope. Analysis by real-time PCR indicated that transgenic silkworms expressing BmRelish1t recombinant proteins displayed higher mRNA expression levels of the Bombyx mori antimicrobial peptides such as lebocin, moricin, and nuecin than the normal silkworms. Moreover, transgenic silkworms expressing BmRelish1t showed antibacterial activity against Escherichia coli. We suggest that transgenic expression of BmRelish1t may find useful applications for the production of various antimicrobial peptides at the same time in transgenic silkworms.

Previously, we performed de novo RNA sequencing of Scolopendra subpinipes mutilans using high-throughput sequencing technology and identified several AMP candidates. Among them, a synthetic peptide (CP112) was designed based on the physicochemical properties of antimicrobial peptide such as length, charge, isoelectric point. Here, we have assessed the antimicrobial activities of CP112 against various microbes and the antioxidative effects. The results showed that CP112 had antimicrobial activities in radial diffusion assay and colony count assay. In addition, we found that CP112 bound to the surface of microorganisms via a specific interaction with lipoteichoic acid, lipopolysaccharide and peptidoglycan, which is one of bacteria cell wall components. Furthermore, CP112 has shown significant DPPH radical scavenging activity. Taken together, the results would be provided the basis for developing of peptide antibiotics and antioxidants.

Insect-derived Kazal-type serine protease inhibitors exhibit thrombin, elastase, plasmin, proteinase K, or subtilisin A inhibition activity, but so far, no functional roles for bee-derived Kazal-type serine protease inhibitors have been identified. In this study, a bee (Apis cerana) venom Kazal-type serine protease inhibitor (AcKTSPI) that acts as a microbial serine protease inhibitor was identified. AcKTSPI contained a single Kazal domain that displayed six conserved cysteine residues and a P1 threonine residue. AcKTSPI was expressed in the venom gland and was present as a 10-kDa peptide in bee venom. Recombinant AcKTSPI Kazal domain (AcKTSPI-Kd) expressed in baculovirus-infected insect cells demonstrated inhibitory activity against subtilisin A (Ki 67.03 nM) and proteinase K (Ki 91.53 nM), but not against α-chymotrypsin or typsin, which implies a role for AcKTSPI as a microbial serine protease inhibitor. However, AcKTSPI-Kd exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or elastase. Additionally, AcKTSPI-Kd bound directly to Bacillus subtilis, B. thuringiensis, Beauveria bassiana, and Fusarium graminearum but not to Escherichia coli. Consistent with these findings, AcKTSPI-Kd showed antibacterial activity against Gram-positive bacteria and antifungal activity against both plant-pathogenic and entomopathogenic fungi. These findings constitute molecular evidence that AcKTSPI acts as an inhibitor of microbial serine proteases. This paper provides a novel view of the antimicrobial functions of a bee venom Kazal-type serine protease inhibitor.

In this study, we selected some material to have potential bioactivity from natural plants, confirmed as basic data for industrializing and tried to develope the food materials using them. DPPH, ABTS, antioxidant protection factor, TBARs and antimicrobial activity of extracts from Rosa multiflora Thunberg fruits were determined. The total phenolics extracted from Rosa multiflora were 12.08, 11.82, 11.1 and 12.6 mg/g when using water, 70% ethanol, 70% methanol and 70% acetone as the solvent, respectively. The optimum conditions for extracting the phenolic compounds were 70% ethanol over for 12 hrs(11.82 mg/g). The electron donating ability and inhibition rate on ABTS of the 70% ethanol extracts were 97% and 92.2%, respectively while the antioxidant protection factor(PF) of the water extracts and 70% ethanol extracts were 1.79 and 1.34 PF, respectively. The TBAR (thiobarbituric acid reactive substance) value were 1.3 μM for the control and 0.15 μM for the 70% ethanol extracts. The inhibitory activity against α-amylase was 26% for the 70% ethanol extracts. The 70% ethanol extracts from Rosa multiflora Thunberg fruits exhibited antimicrobial activity against H. pylori, S. epidermidis, S. aureusand and E. coli with clear zone diameters of 14, 25, 14 and 13 mm, respectively when using 200 μg/mL of the phenolic compounds. An HPLC analysis identified 6 major phenolic metabolites in the Rosa multiflora Thunberg fruits extracts: rosmarinic acid, caffeic acid, chlorogenic acid, courmaric acid, protocatechuic acid and quercetin. In particular, the content of rosmarinic acid was the highest in the 70% ethanol extracts. Therefore these results indicate that 70% ethanol extracts from Rosa multiflora Thunberg fruits can be useful as a natural antioxidant and in functional foods.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causative microbes for nosocomial infe- ction and has been isolated from the dental environment. The purpose of this study was to investigate the antimi- crobial activity of linalool and α‐terpineol against MRSA isolates from a Korean population. In the experiments, we determined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two compounds against 18 strains of MRSA. The data re- vealed that the MIC90/MBC90 values of linalool and α‐ terpineol against MRSA were >12.8 mg/ml and 6.4 mg/ml, respectively. These results indicate that α-terpineol has more potent antimicrobial activity against MRSA than lina- lool and may have utility as an anti‐MRSA cleansing agent for dental instruments and dental unit chairs.

살균제 저항성 Bacillus cereus 분리주의 포자에 살균제와 열을 가해 그 병합효과를 비교하였다. 사용된 B. cereus 균주는 차아염소계 처리 후 분리한 균주(S-BC-50, S-BC-52), 과산화수소 처리 후 분리한 균주(S-BC-23, S-BC-48), acetic acid 처리 후 분리한 균주(S-BC-54, S-BC-56)와 표준균주 B. cereus KCTC1661을 사용하였다. B. cereus 분리주의 포자를 다음 조건으로 처리하였다; i) 0.56% 과산화수소수(HP), ii) 3% acetic acid(AA), iii) 80oC 열처리(H80), iv) 90o 열처리(H90), v) HP+H80, vi) HP+H90, vii) AA+H80, viii) AA+H90. 포자를 HP와 AA 처리에 노출시킨 결과 포자가 감소하지 않았지만, H80과 H90 처리에서는 1~2 log CFU/mL가 감소하였다(P<0.05). 병합처리(HP+H80, HP+H90, AA+H80, AA+H90)에 포자를 적용시킨 경우, 포자수가 3-6 log CFU/mL 감소 하였지만, AA+H80과 AA+H90은 AA만 처리했을 때보다 오히려 포자 제어가 감소했다. 따라서 HP와 열처리를 병합했을 때는 B. cereus 포자를 불활성화하기에 효과적이지만, AA의 경우 B. cereus 포자가 열처리에 대한 저항성을 증가시키는 것으로 사료된다.

The Hypsizigus marmoreus has been used as medicinal and food source in worldwide. Viridans Streptococci, which include Streptococcus sanguinis and Streptococcus gordonii, are pioneer oral bacteria that initiate dental plaque formation. This study was to investigate the antimicrobial activity of Hypsizigus marmoreus Extracts. Antimicrobial activity of extracts were tested against pathogenic bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus sanguinis and Streptococcus gordonii) by paper disc methods. The Hypsizigus marmoreus Extracts were extracted with 80% methanol. The 80% methanol extracts of Hypsizigus marmoreus Extracts showed antimicrobial activity against S. sanguinis and S. gordonii. The 80% methanol extract of Hypsizigus marmoreus Extracts were fractioned by hexane, chloroform, ethylacetate and buthanol. The ethylacetate fraction of Hypsizigus marmoreus Extracts showed strong antimicrobial activity against S. sanguinis and S. gordonii with minimum inhibitory concentration (MIC) range of 0.8-1 mg/ml. Especially, the 80% methanol extract and ethylacetate fraction of Hypsizigus marmoreus Extracts were inhibited the biofilm formation of S. sanguinis and S. gordonii at a concentration of 1.0 mg/ml. These results suggest that Hypsizigus marmoreus extracts can be developed as a potent antimicrobial agent.

The antimicrobial peptide cecropin was isolated from the larval hemolymph of immune-challenged japanese oak silkworm, Antheraea yamamai. The full-length cDNA of A. yamamai cecropin (Ay-cecA) was cloned by a combination of RT-PCR and 3' RACE based on N-terminal sequence obtained by Edman degradation. The cloned cDNA consists of 419 nucleotides encoding a 64 amino acid precursor containing a 37-residue mature peptide. Like many insect cecropins, Ay-cecA also harbored a glycine residue for C-terminal amidation at the C-end. To understand this peptide better, we successfully expressed bioactive recombinant Ay-cecA in E. coli BL21(DE3) by fusing with ketosteroid isomerase (KSI) to avoid the cell death during induction. The fusion CecA-KSI protein was expressed as inclusion body at high level. Recombinant Ay-cecA was easily released by cleavage of the fusion protein with cyanogen bromide (CNBr), and purified by FPLC chromatography. The purified recombinant Ay-cecA showed considerably antibacterial activity against Gram-negative bacteria, E. coli ML 35, Klebsiella pneumonia and Pseudomonas aeruginosa. The time-kill assay showed that Ay-CecA displayed a time-dependent bactericidal activity, as was also seen after treatment with melittin. our results proved that Ay-cecA can be developed into novel antibacterial agent.

Entomopathogenic fungi are natural pathogens of insects and contribute to the regulation of host insect populations in the environment. Several these fungi produce a wide range of secreted enzymes, secreted protein toxins and secondary metabolites to overcome host defenses and ultimately kill the host, and to defend host resources against competing pathogens and saprophytes. This study was performed to evaluate the antimicrobial activity of 207 entomopathogenic fungi form Korea soils against plant pathogenic bacteria Ralstonia solanacearum and plant pathogenic fungi Botrytis cinerea using dual culture technique on SDYA. As results, twelve isolates (5.7%) and six isolates (2.8%) showing the greatest inhibition against R. solanacearum and B. cinerea, respectively. The culture supernatant of these selected isolates completely suppressed the growth of the pathogen, indicating that suppression was due to the presence of antimicrobial compound in the culture filtrate. The stability test of the culture filtrate showed that the antimicrobial component was heat stable and not protein. These entomopathogenic fungal metabolites may be a good feature to be used in the development of a new biocontrol method of R. solanacearum and B. cinerea.

Antimicrobial resistance and multi-drug resistance patterns have been carried out on total of 210 isolated of Salmonella spp. and pathogenic E. coli isolated from food poisoning patients on January through December 2012 in Incheon, Korea. The highest percentage of antibiotics resistance was found to the following antimicrobial agents: tetracycline 43.8%, ampicillin 34.8%, nalidixic acid 23.8%, sulfamethoxazole/trimethoprim and chloramphenicol 12.4%, and ampicillin/sulbactam 11.4%. The highest percentage of resistance was 37.5% to ampicillin for Salmonella spp. and 59.0% to tetracycline for pathogenic E. coli. Overall the multidrug resistance rates of 1 drug was 26.2%, 2 drugs 9.0%, 3 drugs 9.5%, 4 drugs 7.1%, and 5 or more drugs 12.46%. The multi-drug (MDR) strains to four or more antimicrobial agents among the resistant organisms were quite high: 15.9% and 22.1% for Salmonella spp. and pathogenic E. coli, respectively. The study implies that limitation of unnecessary medication use is pertinent in order to maintaining the efficacy of drugs.

본 연구는 항균성 코팅제의 개념과 동향파악으로 항균성 코팅제의 연구개발의 방향을 설정하는데 도움을 주기 위한 것이다. 항균제는 미생물을 제거하거나 성장을 저지하는데 사용되는 화합물이며 항균 코팅제에 함유되는 항균제용 재료는 무기물, 금속, 저분자 유기물, 천연유기물, 고분자가 있다. 항균코팅제는 생활용품, 병원용품, 산업용품, 전자제품, 의류, 건축 내장재 등의 표면의 항균성 부여에 쓰인다. 기존 항생제는 세균의 세포벽을 손상하지 않고 미생물을 침투하나 항균성 고분자는 세포막을 파괴하므로 항생제의 내성을 방지할 수 있다. 대부분의 고분자 항균제는 양이온 고분자에 초점을 맞추고 있다. 항균제의 분자설계와 코팅제 배합의 합리화로 항균제의 선택성, 내구성, 독성 문제가 개선될 것이다.

In this study, antimicrobial and antioxidative activities were investigated using the hot water extracts of Rhus verniciflua Stokes (RVS) in order to develop RVS as a natural antimicrobial and antioxidative material. The antimicrobial activity was not found against five strains of yeasts (Saccharomyces cerevisiae, Saccharomyces pastorianus, Torulaspora delbrueckii, Zygosaccharomyces rouxii, and Zygosaccharomyces bailii) while the activity was confirmed against five strains of bacteria (Bacillus subtilis, Staphylococcus aureus, Bacillus licheniformis, Escherichia coli, and Pseudomonas aeruginosa) at the RVS extract concentration of 0.2-1.0% (w/v) by plate cultural method. In the investigation for 24 hours by turbidometry, the antimicrobial activity showed a relatively high growth inhibition of 79.7% against Bacillus subtilis. The highest growth inhibition of 82.6% was against Bacillus licheniformis at the RVS extract concentration of 2,000 μg/mL. The lowest growth inhibition was 25.7-44.1% against E. coli at the extract concentration of 250 μg/mL and 2,000 μg/mL. The total polyphenol and flavonoid contents of the RVS extract were 42.48 mg/g and 5.42 mg/g, respectively. The highest antioxidative activity at 79.15% was observed at the RVS extract concentration of 0.5 mg/mL by DPPH. Also the antioxidative activity by ABTS demonstrated the highest level at 81.56% at the same concentration. It can be gleaned from these results that the hot water extract of RVS has a great potential to be a natural antioxidant and antimicrobial material against gram positive bacteria(Bacillus subtilis and Bacillus licheniformis).

목적: Polyhexamethylene biguanide (PHMB)와 Epigallocatechin-gallate (EGCG) 혼합물의 각막염 유발 균주에 대한 항균효과를 검사하고 콘택트렌즈 관리용액의 항균제로서의 가능성을 판단하고자 하였다. 방법: 국제표준화기구(International Organization for Standardization, ISO)가 규정한 황색포도상 구균(Staphylococcus aureus), 메티실린내성 황색포도상구균(Methicillin-resistant Staphylococcus aureus), 녹농균(Pseudomonas aeruginosa), 세라티아 마르세센스(Serratia marcescens), 칸디다 알비캔 스(Candida albicans), 푸사리움 솔라니(Fusarium solai)를 각각의 액체배지에 접종한 후 각 균주들의 적정 배양온도에서 24시간동안 활성화시켰다. 활성화된 균주는 96-well plate를 사용하여 PHMB와 EGCG를 각 각 0.0000125~0.0004%, 0.0025~0.3% 함유한 액체배지에서 배양하였고, PHMB/EGCG 혼합물은 PHMB 최소저해농도(MIC, 0.00005%)와 0.0125~0.1%의 EGCG가 포함되도록 하여 12시간 동안 배양하였다. 배양 후 항균력은 600nm에서 흡광도를 측정하여 확인하였다. 결과: ISO 규정 안질환 균주에 대한 EGCG 최소저해농도는 PHMB보다 높아(100~1,500배) 항균력은 낮은 것으로 평가되었다. PHMB/EGCG 혼합물의 ISO 규정 안질환 균주에 대한 최소저해농도는 0.00005%/ 0.05%로 PHMB 최소저해농도의 25% 수준에서도 충분한 항균효과를 나타내었다. 결론: PHMB와 EGCG 혼합물은 ISO 규정 안질환 균주에 대하여 항균 시너지 효과를 나타내어 다목적 용액에 사용하는 PHMB 농도를 낮출 수 있을 것으로 보이며 이 결과는 콘택트렌즈 관리용액 개발에 기초자료로 활용될 수 있을 것으로 사료된다.

Saliva from the oral cavity was collected from 129 patients with periodontitis and 54 Staphylococcus aureus isolates were isolated from these samples. The S. aureus isolates were tested for their resistance patterns against 15 antibiotics using the disc diffusion method. The percentage of S. aureus isolates resistant to ampicillin was the highest (92.6%). In addition, the percentage of S. aureus isolates resistant to penicillin, oxacillin, cefotetan, cefepime and erythromycin was 90.7%, 11.1%, 11.1%, 9.3% and 5.6%, respectively. However, S. aureus isolates were susceptible to gentamycin, clindamycin, trimethoprim/sulfamethoxazole and vancomycin. 96.3% of S. aureus isolates were resistant to antibiotics. Among them, the percentage of two antibiotic-resistant S. aureus isolates was 74.1%, the percentage of one antibiotic-resistant S. aureus isolates was 5.6%, the percentage of three antibiotic-resistant S. aureus isolates was 3.7% and the percentage of S. aureus isolates resistant to more than 4 antibiotics was 13%. The most common multiple antimicrobial resistance pattern was AM-P. Furthermore, the percentage of methicillin-resistant S. aureus isolates was 11.1% and they were resistant to more than 3 antibiotics.

국내 마늘의 품종과 관련한 연구는 산지에 따른 비교로 한정되어 있어 마늘의 성분 및 특성에 대한 기 초자료를 확보하고자 품종별 마늘 시료 12종을 대상으로 이화학적 특성과 항균활성을 분석하였다. 품종별 마늘의 구폭은 캘리포니아 만생종(60.44mm, 53.73g)이 가장 크고 무거웠으며, 창녕종(44.04mm, 25.15g)이 가장 작고 가벼웠다. 품종별 마늘의 표면색 중 L값은 84.13∼90.56, a값은 –1.10∼0.77, b값은 18.24∼26.61의 범위였다. 전단가는 캘리포니아 조생종이 가장 낮았으며, 94-12-2종은 4211.35 cm/kg2 으로 타 시료에 비하여 전단가가 가장 높았다. 가용성 고형분 함량은 6.40∼11.33 %brix의 범위였는데, 창녕종에서 유의적으로 높았다. 품종별 마늘의 pH는 5.57∼6.53의 범위였다. 총 thiosulfinate 함량은 이 태리종이 93.23 mM/g로 가장 낮았고, 캘리포니아 만생종이 146.05 mM/g로 가장 높았다. 총 pyruvate 함량은 유고종(162.50μM/g)에서 가장 높았고, 캘리포니아 조생종(147.41μM/g)에서 가장 낮았다. 품종 별 마늘의 추출물로 항균활성을 측정한 결과, Streptococcus mutans균에서 활성이 가장 낮았으며, Escherichia coli균에 대한 항균 활성이 높았

목적: 합성보존제 성분인Polyhexamethylene biguanide (PHMB)와 PHMB가 첨가된 다목적용액의 국제표준화기구(International Organization for Standardization, ISO)가 규정한 균주에 대한 항균력을 비교하고, 콘택트렌즈 관리용액에 적합한PHMB 농도를 확인하기 위해 본 연구를 수행하였다. 방법: 항균력 측정을 위하여 배양된 황색포도상구균(Staphylococcus aureus), 메치실린내성 황색포도상구균(Methicillin-resistant Staphylococcus aureus), 녹농균(Pseudomonas aeruginosa), 세라티아 마르세센스(Serratia marcescens), 칸디다 알비캔스(Candida albicans), 푸사리움 솔라니(Fusarium solai)를 각각의 액체배지에 접종한 후 각 균주들의 적정 배양온도에서 24시간동안 활성화시켰다. 활성화된 균주는 96-well plate를 사용하여 PHMB 용액과 PHMB를 첨가한 다목적용액의 PHMB 농도가 0.0000125%~0.0004%인 배양액에서 12시간 배양한 후 600nm에서 흡광도를 측정하여 항균력을 비교하였다. 결과: 생육억제를 나타내는 최소저해농도는 순수한 PHMB가 PHMB를 첨가한 다목적용액에 비하여 황색포도상구균, 메치실린내성 황색포도상구균, 녹농균, 세라티나 마르세센스, 칸디다 알비캔스에서 2배 높게 나타났다. 다목적용액에 포함된 0.0002% PHMB 농도는 국제표준화기구에서 규정한 균주에 대한 충분한 항균력을 나타내었다. 결론: 다목적용액에 포함된PHMB의 농도는 순수한 PHMB 최소저해농도보다 낮지만, 용액에 포함된 다른 첨가물에 의해 항균시너지효과를 나타냄을 확인하였다.

벤질리덴아세톤(benzylinedeneacetone: BZA)은 두 곤충병원세균인 Xenorhabdus nematophila와 Photorhabdus temperata subsp. temperata에서 유래된 대사산물의 일종이다. 이 물질은 곤충의 세포성 및 체액성 면역반응을 억제하며 또한 다양한 세균이나 곰팡이에 대해 항생효과를 갖고 있다. 그러나 이 물질이 갖는 비교적 높은 약해와 낮은 식물체 침투력은 효과적 농약으로 개발하는 데 어려움을 주고 있다. 본 연구에서는 다섯 개의 서로 다른 BZA 유사체를 스크리닝하여 면역억제 및 항균활성을 유지하면서 비교적 용해도가 높고 약해가 낮은 물질을 선발하였다. BZA의 벤젠 고리에 수산기가 붙은 유도체는 면역억제 및 항균활성이 뚜렷이 낮아졌다. 또한 BZA의 케톤기를 카르복실기로 변형하면 면역억제와 항균활성을 잃게 되었다. 그러나 BZA의 탄화수소 사슬을 짧게 하여 형성된 아세테이트 유도체인 4-hydroxyphenylacetic acid (HPA)는 면역억제와 항균활성을 잃지 않았다. 또한 HPA는 BZA 보다 고추(Capsicum annuum)에 대해 약해가 낮은 것으로 나타났다. 이 연구는 낮은 약해를 유발하면서 높은 곤충면역억제와 식물병원균에 대해 높은 항균활성을 보이는 BZA 유도체를 선발하였다.