• Asian-Australasian Journal of Animal Sciences
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• 제27권2호
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• pp.278-283
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• 2014

Cecropins (Cec) are antibacterial peptides and their expression is induced in a pig intestinal parasite Ascaris suum by bacterial infection. To explore the usefulness of its activity as an antibiotic, CecP4 cDNA was prepared and cloned into the pPICZ B expression vector and followed by the integration into AOX1 locus in Pichia pastoris. The supernatants from cell culture were collected after methanol induction and concentrated for the test of antimicrobial activity. The recombinant P. patoris having CecP4 showed antimicrobial activity when tested against Staphyllococcus aureus in disc diffusion assay. We selected one of the CecP4 clones (CecP4-2) and performed further studies with it. The growth of recombinant P. pastoris was optimized using various concentration of methanol, and it was found that 2% methanol in the culture induced more antibacterial activity, compared to 1% methanol. We extended the test of antimicrobial activity by applying the concentrated supernatant of CecP4 culture to Pseudomonas aeruginosa and E. coli respectively. Recombinant CecP4 also showed antimicrobial activity against both Pseudomona and E. coli, suggesting the broad spectrum of its antimicrobial activity. After improvements for the scale-up, it will be feasible to use recombinant CecP4 for supplementation to the feed to control microbial infections in young animals, such as piglets.

• 대한화학회지
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• 제55권4호
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• pp.650-655
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• 2011

새로운 펩티드 유사체인 5a-c를 5-amino benzimidazoles 2a-c과 L-phenylalanine과의 커플링반응에 의해 합성하였다. Phenylalanine의 amine 부분을 phthalic anhydride로 보호하고, 나머지 작용기인 carboxylic acid를 염소화시켜서 hthaloyl-Lphenylalanyl chloride 4를 합성한 다음에, 화합물 2a-c와 반응시켜서 화합물 5a-c를 합성하였다. 얻어진 화합물 5a-c를 hydrazine으로 반응시켜서 새로운 펩티드 유사체인 6a-c를 합성하였으며, 얻어진 화합물에 대한 항균성을 측정하였다.

• 한국해양바이오학회지
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• 제14권1호
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• pp.9-24
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• 2022

Low-molecular weight peptides derived from fish collagen exhibit several bioactivities, including antioxidant, antiwrinkle, antimicrobial, antidiabetic, and antihypertension effects. These peptides are also involved in triglyceride suppression and memory improvement. This study aimed to investigate the optimal processing condition for preparing low-molecular weight peptides from flounder skin, and the properties of the hydrolysate. The optimal processing conditions for peptic hydrolysis were as follows: a ratio of pepsin to dried skin powder of 2% (w/w), pH of 2.0, and a temperature of 50℃. Peptic hydrolysate contains several low-molecular weight peptides below 300 Da. Gly-Pro-Hyp(GPHyp) peptide, a process control index, was detected only in peptic hydrolysate on matrix-assisted laser desorption/ionization-time-of-flight(MALDI-TOF) spectrum. 2,2'-azinobis-(3-3-ethylbenzothiazolline-6- sulfonic acid(ABTS) radical scavenging activity of the peptic hydrolysate was comparable to that of 1 mM ascorbic acid, which was used as a positive control at pH 5.5, whereas collagenase inhibition was five times higher with the peptic hydrolysate than with 1 mM ascorbic acid at pH 7.5. However, the tyrosinase inhibition ability of the peptic hydrolysate was lower than that of arbutin, which was used as a positive control. The antibacterial effect of the peptic hydrolysate against Propionibacterium acne was not observed. These results suggest that the peptic hydrolysate derived from a flounder skin is a promising antiwrinkle agent that can be used in various food and cosmetic products to prevent wrinkles caused by ultraviolet radiations.

• International Journal of Industrial Entomology and Biomaterials
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• 제31권2호
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• pp.85-89
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• 2015

This peptide has antibacterial activity against several Gram-positive and Gram-negative bacteria. Bombyx mori cecropinB1(BmCecB1) is antimicrobial peptides from Bombyx mori and belongs to cecropin family. Antimicrobial peptides are important components of the innate immune systems in all living organism. 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 9%. 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.

• Journal of Microbiology and Biotechnology
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• 제30권9호
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• pp.1305-1309
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• 2020

Insects possess biological defense systems that can effectively combat the invasion of external microorganisms and viruses, thereby supporting their survival in diverse environments. Antimicrobial peptides (AMPs) represent a fast-acting weapon against invading pathogens, including various bacterial or fungal strains. A 37-residue antimicrobial peptide, papiliocin, derived from the swallowtail butterfly Papilio xuthus larvae, showed significant antimicrobial activities against several human pathogenic bacterial and fungal strains. Jelleines, isolated as novel antibacterial peptides from the Royal Jelly (RJ) of bees, exhibit broad-spectrum protection against microbial infections. In this study, we developed a novel antimicrobial peptide, PAJE (RWKIFKKPFKISIHL-NH₂), which is a hybrid peptide prepared by combining 1-7 amino acid residues (RWKIFKK-NH₂) of papiliocin and 1-8 amino acid residues (PFKISIHL-NH₂) of Jelleine-1 to alter length, charge distribution, net charge, volume, amphipaticity, and improve bacterial membrane interactions. This novel peptide exhibited increased hydrophobicity and net positive charge for binding effectively to the negatively charged membrane. PAJE demonstrated antimicrobial activity against both gram-negative and gram-positive bacteria, with very low toxicity to eukaryotic cells and an inexpensive process of synthesis. Collectively, these findings suggest that this novel peptide possesses great potential as an antimicrobial agent.

• Fisheries and Aquatic Sciences
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• 제22권6호
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• pp.13.1-13.9
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• 2019

Background: Marine invertebrates are well known as pivotal bioresources with bioactive substances such as anti-inflammatory sterols, antitumor terpenes, and antimicrobial peptides. However, there are few scientific reports on chemical compositions and bioactivities of marine invertebrates from the East Sea of South Korea. Methods: In this study, chemical compositions and biological activities were evaluated on both 70% EtOH and hot water extracts of 5 species of marine invertebrates (Crossaster papposus japonicus, Actinostola carlgreni, Stomphia coccinea, Actinostola sp., and Heliometra glacialis) collected from the East Sea of South Korea. The antioxidant activities were measured by ABTS radical scavenging assay. The cytotoxicity and anti-inflammatory activity were evaluated using MTT and Griess reagents. Moreover, the antibacterial effect was evaluated using paper disc assay and minimum inhibitory concentration (MIC) assay. Results: In the results of antioxidant activities, 70% EtOH extract of A. carlgreni showed the highest activity ($IC_{50}\;0.19{\pm}0.03mg/ml$) compared to other extracts. Moreover, 70% EtOH extract of A. carlgreni could significantly suppress the nitric oxide (NO) production in lipopolysaccharide-induced RAW 264.7. All extracts treated under $400{\mu}g/ml$ have no cytotoxic effects on RAW 264.7 macrophages. In the antibacterial test, both 70% EtOH extracts of C. papposus japonicus and H. glacialis showed a significant antibacterial effect on Staphylococcus aureus. The MIC values were evaluated at 256 and $512{\mu}g/ml$, respectively. Conclusions: These results suggested the bioactive potentials of marine invertebrates from the East Sea of South Korea in pharmaceutical and nutraceutical applications.

• Journal of Veterinary Science
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• 제25권1호
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• pp.12.1-12.10
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• 2024

Background: Staphylococcus aureus and S. pseudintermedius are the major etiological agents of staphylococcal infections in humans, livestock, and companion animals. The misuse of antimicrobial drugs has led to the emergence of antimicrobial-resistant Staphylococcus spp., including methicillin-resistant S. aureus (MRSA) and methicillin-resistant S. pseudintermedius (MRSP). One novel therapeutic approach against MRSA and MRSP is a peptide nucleic acid (PNA) that can bind to the target nucleotide strands and block expression. Previously, two PNAs conjugated with cell-penetrating peptides (P-PNAs), antisense PNA (ASP)-cmk and ASP-deoD, targeting two essential genes in S. aureus, were constructed, and their antibacterial activities were analyzed. Objectives: This study analyzed the combined antibacterial effects of P-PNAs on S. aureus and S. pseudintermedius clinical isolates. Methods: S. aureus ATCC 29740 cells were treated simultaneously with serially diluted ASP-cmk and ASP-deoD, and the minimal inhibitory concentrations (MICs) were measured. The combined P-PNA mixture was then treated with S. aureus and S. pseudintermedius veterinary isolates at the determined MIC, and the antibacterial effect was examined. Results: The combined treatment of two P-PNAs showed higher antibacterial activity than the individual treatments. The MICs of two individual P-PNAs were 20 and 25 µM, whereas that of the combined treatment was 10 µM. The application of a combined treatment to clinical Staphylococcus spp. revealed S. aureus isolates to be resistant to P-PNAs and S. pseudintermedius isolates to be susceptible. Conclusions: These observations highlight the complexity of designing ASPs with high efficacy for potential applications in treating staphylococcal infections in humans and animals.

• Journal of Microbiology and Biotechnology
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• 제25권10호
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• pp.1629-1633
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• 2015

Peptide assimilation in Helicobacter pylori necessitates a coordinated working of the peptide transport systems (PepTs) and aminopeptidase (PepA). We found that H. pylori hydrolyzes two detector peptides, _L-phenylalanyl- _L-3-thiaphenylalanine (PSP) and _L-phenylalanyl- _L-2-sulfanilylglycine (PSG), primarily before intake and excludes their antibacterial effects, whereas Escherichia coli readily transports them with resultant growth inhibition. PSP assimilation by H. pylori was inhibited by aminopeptidase inhibitor bestatin, but not by dialanine or cyanide-m-chlorophenylhydrazone, contrary to that of E. coli. RT- and qRT-PCR analyses showed that H. pylori may express first the PepTs (e.g., DppA and DppB) and then PepA. In addition, western blot analysis of PepA suggested that the bacterium secretes PepA in response to specific inducers.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1447-1455
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• 2009

Two novel avian $\beta$-defensins (AvBDs) isolated from duck liver were characterized and their homologies with other AvBDs were analyzed. They were shown to be duck AvBD9 and AvBD10. The mRNA expression of the two genes was analyzed in 17 different tissues from 1-28-day-old ducks. AvBD9 was differentially expressed in the tissues, with especially high levels of expression in liver, kidney, crop, and trachea, whereas AvBD10 was only expressed in the liver and kidney of ducks at all the ages investigated. We produced and purified GST-tagged recombinant AvBD9 and AvBDI0 by expressing the two genes in Escherichia coli. Both recombinant proteins exhibited antimicrobial activity against several bacterial strains. The results revealed that both recombinant proteins retained their antimicrobial activities against Staphylococcus aureus under a range of different temperatures ($-70^{\circ}C-100^{\circ}C$) and pH values (pH 3-12).

• 한국미생물·생명공학회지
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• 제38권1호
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• pp.84-92
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• 2010

B. subtilis MJP1이 생산하는 항균물질을 분리 정제하기 위하여 SPE, IEC, GFC를 통한 정제를 수행하였다. 정제된 항세균 물질은 tricine SDS-PAGE에서 하나의 band임을 확인 한 후 N-말단 아미노산 서열분석을 하였으나 N-말단이 blocking 되어 그 서열을 분석할 수 없였다. 이에 그 내부서열을 알아보기 위한 LC를 이용한 ESI-MS/MS를 시행하였으나 내부서열도 확인할 수 없었고, UPLC를 이용한 ESI-MS/MS를 시행한 결과 항세균 활성 물질은 분자량이 매우 유사한 2개의 peptide(3356.54 Da, 3400.5244 Da)가 존재함을 확인하였다. 정제된 항세균 물질의 항균 spectrum을 조사한 결과, L. monocytogenes에 가장 강한 항균활성을 나타내며 이외에 B. subtilis, S. aureus subsp. aureus, E. faecalis 등의 Gram 양성균에서 항균활성을 나타내였다. 정제된 B. subtilis 항세균 물질은 pH 3.0부터 pH 9.0 범위에서는 안정하였으며 $4^{\circ}C$, $30^{\circ}C$, $50^{\circ}C$에서 24시간, $100^{\circ}C$에서 5분 동안 매우 안정하였고, $70^{\circ}C$에서 24 시간, $100^{\circ}C$에서 30분 동안 처리한 구간부터 역가가 감소하여 $121^{\circ}C$에서 15분 동안 처리한 구간에서는 역가가 완전히 소실되었다. 효소 안정성 실험에서 정제된 항세균 물질은 일부 단백분해효소에 의해 분해되어 역가를 상실하였으며, lipase나 $\alpha$-amylase에서는 안정함을 나타냈다. 이로부터 정제된 항세균 물질이 넓은 pH 범위에서 안정하고, 비교적 높은 온도에서도 활성을 유지한다는 점을 관찰할 수 있었으며, 단백분해효소에 의해 분해되므로 bacteriocin임을 확인하였다. 본 연구를 통하여 B. subtilis MJP1으로부터 분리 정제된 bacteriocin은 class IIa군의 특성과 유사하며, B. subtilis MJP1은 본 분리 bacteriocin 이외에도 다른 항세균 물질과 항진균 물질을 생산하는 균주임을 알 수 있었다.