• Microbiology and Biotechnology Letters
• /
• v.50 no.1
• /
• pp.157-163
• /
• 2022

Alcoholic liver disease (ALD), which encompasses alcoholic steatosis, alcoholic hepatitis, and alcoholic cirrhosis, is a major cause of morbidity and mortality worldwide. Although the economic and health impacts of ALD are clear, few advances have been made in its prevention or treatment. We recently demonstrated that the insect-derived antimicrobial peptide CopA3 exerts anti-apoptotic and anti-inflammatory activities in various cell systems, including neuronal cells and colonic epithelial cells. Here, we tested whether CopA3 inhibits ethanol-induced liver injury in mice. Mice were intraperitoneally injected with ethanol only or ethanol plus CopA3 for 24 h and then liver injury and inflammatory responses were measured. Ethanol enhanced the production of proinflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interferon (IFN)-γ, and IL-10. It also induced hepatocyte apoptosis and ballooning degeneration in hepatocytes. Notably, all these effects were eliminated or significantly reduced by CopA3 treatment. Collectively, our findings demonstrate that CopA3 ameliorates ethanol-induced liver cell damage and inflammation, suggesting the therapeutic potential of CopA3 for treating ethanol-induced liver injury.

• Journal of Life Science
• /
• v.25 no.6
• /
• pp.715-723
• /
• 2015

Insects represent the largest class within the animal kingdom in terms of species number. Humans had been utilized insect in the broad area, including food, agriculture, industry, pharmaceuticals and so on. At present, insects are emerging as a leading group for identifying and extracting novel bioactive substances due to enormous number and a high nutritional value. Insects rely on a suite of systemic response to resist infection such as immune cells, hemocytes, activation of enzymes cascades, and antimicrobial peptide/protein. Among the substances, antimicrobial peptides (AMPs) are main components of potent antimircrobial innate defense system into the insect hemolymph. AMPs raise influential candidate as avenue to resolve the development of antibiotic-resistant microbial organism. Insect AMPs are classified into four main classes: cecropins, insect defensins, glycine/proline-rich peptides. Insect AMPs have been purified, over 150. In this review, AMPs derived from several insects were summarized including honey bee, dung beetle, butterfly and longicorn beetle. These peptides almost exhibited potent antimicrobial activities against human microbial pathogens without causing remarkable hemolysis to erythrocytes excluding melittin, and their mode of action(s) are based on disruption of the plasma membrane or fungal apoptosis. Therefore, study of insect AMPs is expected to be useful for designing novel therapeutic antimicrobial applications.

• Journal of Sericultural and Entomological Science
• /
• v.50 no.2
• /
• pp.145-149
• /
• 2012

Cecropin is a well-studied antimicrobial peptide that play important role as key factor in insect humoral immunity. In this study, cecropin-like antimicrobial peptide was isolated and purified from the larval haemolymph of immune-challenged japanese oak silkworm, Antheraea yamamai. To isolate antimicrobial peptide, we separated and compared acidic extracted hemolymph protein bends between control and immune-challenged larvae using SDS-PAGE analysis. In the immune hemolymph extract, but not of non-immune hemolymph, we detected differential expressed peptide band with molecular mass 4,223.01 Da. To understand this peptide better, we successfully purified this peptide using cation exchange chromatography and gel permeation chromatography. Its N-terminal amino acid sequence obtained by Edman degradation evidenced a significant degree of identity with other lepidopteran cecropins. The purified A. yamamai cecropin-like peptide showed a broad spectrum of activity against fungi, Gram-negative and Gram-positive bacteria.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.1
• /
• pp.30-36
• /
• 2019

Numerous studies have reported that enteric neurons involved in controlling neurotransmitter secretion and motility in the gut critically contribute to the progression of gut inflammation. Clostridium difficile toxins, which cause severe colonic inflammation, are also known to affect enteric neurons. Our previous study showed that C. difficile toxin A directly induces neural cell toxicities, such as viability loss and apoptosis. In the current study, we attempted to identify a potent inhibitor of toxin A-induced neural cell toxicity that may aid in managing toxin A-induced gut inflammation. In our recent study, we found that the Korea dung beetle-derived antimicrobial peptide CopA3 completely blocked neural cell apoptosis caused by okadaic acid or 6-OHDA. Here, we examined whether the antimicrobial peptide CopA3 inhibited toxin A-induced neural cell damage. In neuroblastoma SH-SY5Y cells, CopA3 treatment protected against both apoptosis and viability loss caused by toxin A. CopA3 also completely inhibited activation of the pro-apoptotic factor, caspase-3. Additionally, CopA3 rescued toxin A-induced downregulation of neural cell proliferation. However, CopA3 had no effect on signaling through ROS/p38 $MAPK/p27^{kip1}$, suggesting that CopA3 inhibits toxin A-induced neural cell toxicity independent of this well-characterized toxin A pathway. Our data further suggest that ability of CopA3 to rescue toxin A-induced neural cell damage may also ameliorate the gut inflammation caused by toxin A.

• 한국균학회소식:학술대회논문집
• /
• 2016.05a
• /
• pp.13-13
• /
• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.

• BMB Reports
• /
• v.35 no.3
• /
• pp.291-296
• /
• 2002

Thanatin, a 21-residue peptide, is an inducible insect peptide with a broad range of activity against bacteria and fungi. It has a C-terminal disulfide loop, like the frog skin secretion antimicrobial peptides of the brevinin family. In this study, we tried to find the effect of a number of amino acids between the disulfide bond. Thanatin showed stronger antibacterial activity to Gram negative bacteria than other mutants, except Th1; whereas, the mutant peptides with deletion had higher activity to Gram positive bacteria than thanatin. An increase in the number of amino acid(s) using the alanine residue decreased the antibacterial activity in all of the bacteria. Th1 with deletion of threonine at position 15 ($Thr^{15}$) showed similar antibacterial activity against Gram-negative bacteria, but had higher activity against the Gram positive bacteria. In order to study the structure-function relationship, we measured liposome disruption by the peptides and CD spectra of the peptides. Th1 also showed the highest liposome leaking activity and α-helical propensity in the sodium dodecyl sulfate solution, compared with other peptides. Liposome disruption activity was closely correlated with the anti-Gram positive bacterial activity. All of the peptides showed no hemolytic activity. Th1 was considered to be useful as an antimicrobial peptide with broad spectrum without toxicity.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.13 no.1
• /
• pp.37-43
• /
• 2006

Enterococcus faecalis was isolated from the body fluid of dead Galleria mellonella larvae. Upon injection of E. faecalis into the hemocoel of G. mellonella, the bacteria destroyed parts of humoral defense systems in the hemolymph. In a test for the proteolytic activity of E. faecalis CS, it was confirmed that the enzyme degraded three well-known a-helical antimicrobial peptides, cecropin A, melittin and halocidin, and abolished their activities. We also determined putative cleavage sites on the primary sequences of three peptides through purification and mass analysis of peptide fragments digested by E. faecalis CS. Furthermore it was found that apolipophorin-III, recently known as a critical recognition protein for invading microbes in the hemolymph of G. mellonella, was also degraded by E. faecalis CS. Taken together, the present work shows that the protease in secretions from E. faecalis destroyed two critical humoral immune factors in the hemolymph of G. mellonella larvae. In addition, this paper demonstrates that the relationship between the host insect and the pathogenic bacteria might provide a valuable model system to study the enterococcal virulence mechanism, which may be relevant to mammalian pathogenesis.

• BMB Reports
• /
• v.47 no.11
• /
• pp.625-630
• /
• 2014

Defensins, which are small cationic molecules produced by organisms as part of their innate immune response, share a common structural scaffold that is stabilized by three disulfide bridges. Coprisin is a 43-amino acid defensin-like peptide from Copris tripartitus. Here, we report the intramolecular disulfide connectivity of cysteine-rich coprisin, and show that it is the same as in other insect defensins. The disulfide bond pairings of coprisin were determined by combining the enzymatic cleavage and mass analysis. We found that the loss of any single disulfide bond in coprisin eliminated all antibacterial, but not antifungal, activity. Circular dichroism (CD) analysis showed that two disulfide bonds, Cys20-Cys39 and Cys24-Cys41, stabilize coprisin's ${\alpha}$-helical region. Moreover, a BLAST search against UniProtKB database revealed that coprisin's ${\alpha}$-helical region is highly homologous to those of other insect defensins.

• Journal of Animal Science and Technology
• /
• v.64 no.6
• /
• pp.1132-1143
• /
• 2022

Insects are a valuable natural source that can produce a variety of bioactive compounds due to their increasing species diversity. CopA3 is an antimicrobial peptide derived from Copris tripartitus (i.e., the dung beetle). It is known to increase the proliferation of colonic epithelial and neuronal stem cells by regulating cell cycle. This research hypothesized that CopA3 can promote the proliferation of porcine muscle satellite cells (MSCs). The effects of CopA3 on porcine MSCs, which are important for muscle growth and regeneration, remain unclear. Here, we investigated the effects of CopA3 on porcine MSCs. According to viability results, we designed four groups: control (without CopA3) and three treatment groups (treated with 5,10, and 25 ㎍/mL of CopA3). At a CopA3 concentration of 5 ㎍/mL and 10 ㎍/mL, the proliferation of MSCs increased more than that observed in the control group. Furthermore, compared to that in the control, CopA3 treatment increased the S phase but decreased the G0/G1 phase ratio. Additionally, early and late apoptotic cells were found to be decreased in the 5 ㎍/mL group. The expressions of the myogenesis-related transcription factor PAX7 and MYOD proteins were significantly upregulated in the 5 ㎍/mL and 10 ㎍/mL groups, whereas the MYOG protein remained undetected in all group. This study suggested that CopA3 promotes muscle cell proliferation by regulating the cell cycle of MSCs and can regulate the activity of MSCs by increasing the expressions of PAX7 and MYOD.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.95-99
• /
• 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.