• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.595-600
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• 1998

In order to investigate a relationship of the structure-antifungal and hemolytic activities between cecropin A(1-8)-magainin 2(1-12) and cecropin A(1-8)-melittin(1-12) hybrid peptides, several analogues with amino acid substitution at positions 10 (Ile) and 16 (Ser) were designed and synthesized. The increase of the hydrophobicity by substituting with Leu, Phe, and Trp at position 16 in cecropin A(1-8)-magainin 2(1-12) did not have a significant effect on antifungal activity but caused a remarkable increase in hemolytic activity. These results indicate that the hydrophobic property at position 16 of cecropin A(1-8)-magainin 2(1-12) is more correlated to hemolytic activity than to antifungal activity. Replacement with Pro at position 10 of cecropin A(1-8)- magainin 2(1-12) and cecropin A(1-8)-melittin (1-12) caused a remarkable decrease in a-helical contents in the 50% TFE solution and induced a reduction in lytic activity against Aspergillus flavus, and Aspergillus fumigatus. These results demonstrate that flexibility at the central hinge region is essential for lytic activity against fungal cells and $\alpha$-helicity of the peptides.

• Asian Pacific Journal of Cancer Prevention
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• 제15권13호
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• pp.5433-5436
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• 2014

Conventional chemotherapy against hepatocellular carcinoma typically causes various side effects. Our previous study showed that cecropin of Musca domestica can induce apoptosis in human hepatocellular carcinoma BEL-7402 cells in vitro. However, whether cecropin inhibits BEL-7402 cell in vivo and the question of possible side effects remained undentified. The present study confirmed tumor-inhibitory effects of cecropin in vivo, and furthermore strongly suggested that cecropin cytotoxicity in BEL-7402 cells in vivo may be mainly derived from its pro-apoptotic action. Specifically, we found that cecropin exerted no obvious side effects in tumor-bearing mice as it had no significant hematoxicity as well as visceral toxicity. Therefore, cecropin may be a potential candidate for further investigation as an antitumor agent against hepatocellular carcinoma.

• BMB Reports
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• 제46권5호
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• pp.282-287
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• 2013

Cecropin A and papiliocin are novel 37-residue cecropin-like antimicrobial peptides isolated from insect. We have confirmed that papiliocin possess high bacterial cell selectivity and has an ${\alpha}$-helical structure from $Lys^3$ to $Lys^{21}$ and from $Ala^{25}$ to $Val^{35}$, linked by a hinge region. In this study, we demonstrated that both peptides showed high antimicrobial activities against multi-drug resistant Gram negative bacteria as well as fungi. Interactions between these cecropin-like peptides and phospholipid membrane were studied using CD, dye leakage experiments, and NMR experiments, showing that both peptides have strong permeabilizing activities against bacterial cell membranes and fungal membranes as well as $Trp^2$ and $Phe^5$ at the N-terminal helix play an important role in attracting cecropin-like peptides to the negatively charged bacterial cell membrane. Cecropin-like peptides can be potent peptide antibiotics against multi-drug resistant Gram negative bacteria and fungi.

• 미생물학회지
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• 제33권3호
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• pp.170-174
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• 1997

강한 항진균 활성을 나타내며, 낮은 적혈구 용혈활성을 갖는 새로운 합성 펩티드를 얻기 위하여 cecropin A(1-8)-magainin 2(1-12) 및 이들의 유사체들을 설계하고 이들을 고상법에 의하여 합성하였다. 합성 펩티드의 항진균 활성은 Trichosporon beigelii에 대한 성장억제능에 의하여 측정하였으며, 세포독성은 인간의 적혈구 세포에 대한 용혈활성에 의하여 측정하였다. 펩티드의 양쪽 친매성의 증가는 항진균활성보다는 적혈구 용혈황성에 큰 영향을 미쳤다. Cecropin A(1-8)-magainin 2(1-12)의 12번 아미노산이 Lys을 Ala으로 치환시킨 유사체 펩티드(A2)는 가장 강한 항진균활성(minimum inhibitory concentration : 2.5.$\mu$g/ml)을 나타내며 비교적 낮은 적혈구 용혈활성(200.$\mu$g/ml의 펩티드 농도에서 0.5% hemolysis를 나타냄)을 나타내었다. 따라서 A2의 펩티드는 세포독성을 갖지 않으며 강한 항진균 활성을 가지는 모델로서 유용하게 사용될 것이다.

• 한국잠사곤충학회지
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• 제52권1호
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• pp.45-51
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• 2014

면역 유도된 천잠(Antheraea yamamai) 유충에서 cecropin-A 유전자를 분리하였고 이 유전자를 Ay-CecA로 명명하였다. 전체 Ay-CecA cDNA 크기는 419 bp로 64개의 아미노산 잔기를 인코딩하는 195 bp ORF로 구성되어 있다. 천잠 CecA 유전자는 22개 잔기의 signal peptide, 4개 잔기의 propeptide 및 항균활성을 갖는 37개 잔기로 구성된 성숙 단백질(mature protein) 영역으로 구성되고 예상 분자량은 4046.81 Da으로 산출되었다. 천잠 CecA의 아미노산 서열은 다른 나비목 곤충에서 분리된 cecropin와 매우 높은 상동성(62 ~ 78%)을 나타냈다. Ay-CecA 유전자의 C말단에 기존에 보고된 곤충의 cecropin에서와 동일하게 C말단 아미드화를 위한 glycine 잔기가 존재하고 있다. 이 펩타이드의 항균활성을 검정하기 위해서 대장균 발현 시스템을 이용하여 활성이 있는 재조합 Ay-CecA 발현에 성공하였다. 발현 기주인 대장균에 대한 재조합 CecA 독성 중화를 위해서 불용성 단백질인 ketosteroid isomerase(KSI) 유전자를 CecA 유전자와 융합하였다. 융합 CecA-KSI 단백질은 대부분 불용성 단백질로 발현되었다. 발현된 융합단백질은 Ni-NTA immobilized metal affinity chromatography(IMAC)에 의해서 정제하였으며 CNBr 반응을 통하여 재조합 CecA를 절단하여 용출하였다. 최종적으로 양이온 교환 chromatography 과정을 통하여 CecA를 순수 정제하였다. 정제된 재조합 Ay-CecA는 그람음성균인 E. cori ML 35, Klebsiella pneumonia 및 Pseudomonas aeruginosa에 대해 매우 높은 항균활성을 나타냈었다. 따라서 본 연구 결과, 높은 항균활성 지닌 CecA는 천잠의 면역 반응에서 중요한 역할을 담당할 것으로 사료된다.

• Journal of Veterinary Science
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• 제22권5호
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• pp.59.1-59.13
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• 2021

Background: Antimicrobial peptides (AMPs) have been identified as promising compounds for consideration as novel antimicrobial agents. Objectives: This study analyzed the efficacy of cecropin B against Haemophilus parasuis isolates through scanning electron microscopy (SEM) and atomic force microscopy (AFM) experiments. Results: Cecropin B exhibited broad inhibition activity against 15 standard Haemophilus parasuis (HPS) strains and 5 of the clinical isolates had minimum inhibition concentrations (MICs) ranging from 2 to 16 ㎍/mL. Microelectrophoresis and hexadecane adsorption assays indicated that the more hydrophobic and the higher the isoelectric point (IEP) of the strain, the more sensitive it was to cecropin B. Through SEM, multiple blisters of various shapes and dents on the cell surface were observed. Protrusions and leakage were detected by AFM. Conclusions: Based on the results, cecropin B could inhibit HPS via a pore-forming mechanism by interacting with the cytoplasmic membrane of bacteria. Moreover, as cecropin B concentration increased, the bacteria membrane was more seriously damaged. Thus, cecropin B could be developed as an effective anti-HPS agent for use in clinical applications.

• BMB Reports
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• 제31권6호
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• pp.536-541
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• 1998

The cDNA clone encoding the antibacterial peptide (SL-1) was isolated from the fat body of the common cutworm, Spodoptera litura, immunized with E. coli K12. The primary structure analysis revealed that its deduced amino acid sequence showed the characteristics of the cecropin family antibacterial peptides and that the amino acid residues highly conserved in the antibacterial peptides from moths and flies were also conserved, implying that SL-1 was a cecropin-like, and especially cecropin B-like, peptide. The predicted secondary structure of the mature SL-1 consists of three domains: (i) an amphiphilic ${\alpha}$-helical domain (Ile-4 to Gly-18); (ii) the hinge region (Gly-23 and Pro-24); and (iii) a hydrophobic domain (Ala-25 to IIe-38).

• International Journal of Industrial Entomology and Biomaterials
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• 제37권2호
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• pp.95-99
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• 2018

In insect defense system, antimicrobial peptides (AMPs) are one of important biological molecules to survive in a variety of environments. Insect can synthesize AMPs to protect against invading pathogens in humoral immune response. Taking more advantage of biological antimicrobial molecules, we report antibacterial activity of two cecropin type peptides, cecropin and moricin, isolated from the silkworm against four salmonella species. In this work, we purified antimicrobial candidate peptides (AMCP) from the extracts of immune challenged silkworm larval hemolymph by two-step chromatographic purification procedure, cation exchange and gel permeation chromatography. The molecular weights of purified peptides were estimated to be about 4 ~ 5 kDa by Tricin SDS-PAGE analysis, and identified as silkworm cecropin and moricin by NCBI BLAST homology search with their N-terminal amino acid sequences. As antibacterial activity assay, the purified peptides showed stronger antibacterial activity against Salmonella pathogens with an MIC value of $1{\sim}4{\mu}g/mL$. Therefore two cecropin type peptides purified from the silkworm will be valuable potential materials for development of new natural antibiotics.

• Journal of Microbiology and Biotechnology
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• 제9권2호
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• pp.168-172
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• 1999

The antifungal mechanism of the antifungal peptide against Aspergillus fumigatus, $K^{18,19}$-CA(l-8)-ME(l-12), derived from cecropin A(l-8)-melittin(l-12) was investigated by confocal laser scanning microscopy, cell wall regeneration, ATPase activity inhibition, and released potassium ion. By confocal laser scanning microscopy, $K^{18,19}$-CA(l-8)-ME(l-12) was detected on the surface of A. fumigatus, while cecropin A used as a negative control peptide was not detected. The protoplast of A. fumigatus treated with$K^{18,19}$-CA(1-8)-ME(1-12) failed to regenerate the fungal cell walls. Compared with cecropin A, the amount of potassium ion released by $K^{18,19}$-CA(l-8)-ME(l-12) was increased. Furthermore, $K^{18,19}$-CA(l-8)-ME(l-12) inhibited the ATPase activity on the plasma membrane. These results suggested that $K^{18,19}$-CA(l-8)-ME(1-12) acts on the plasma membrane of A. fumigatus and its antifungal action is due to the ion channel or pore formation on the plasma membrane.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
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• pp.32-32
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• 1999

Cecropin A(1-8)-magainin 2(1-12) and cecropm A(1-8)-melittin(1-12) hybrid peptides were known to have potent antitumor and antibacterial activity. In particular, cecropm A(l-8)-magainin 2(1-12) has powerful antibacterial and antitumor activity with no hemolytic effect.(omitted)