Search Results (29)

Rice plants are important food crops that are sensitive to cold stress. Microtubules (MTs) are highly associated with plant response to cold stress. The exogenous application of abscisic acid (ABA) can transiently induce the cold stability of microtubules. These phenotypes were accompanied by the transient increase in Phospholipase D (PLD) enzyme activity. The analysis of detyrosinated/tyrosinated α-tubulin by Western blot in the NtTUA3 line or in the NtTUA3+OsTTL line gave us such a conclusion that the effect of ABA on detyrosinated α-tubulin not only was regulated by ABA but also was dependent on the TTLL12 protein. The dual ABA and 1% n-butanol treatments had shown that ABA-induced detyrosinated α-tubulin in a manner distinct from the n-butanol pathway. Detecting the detyrosinated α-tubulin level after pre-treatment with pertussis toxin (PTX), a G-protein inhibitor, followed by ABA, as well as mastoparan (Mas7) treatment suggested that the effect of ABA on detyrosinated α-tubulin was dependent on PLD activity. Full article

Skin wound healing is coordinated by a delicate balance between proinflammatory and anti-inflammatory responses, which can be affected by opportunistic pathogens and metabolic or vascular diseases. Several antimicrobial peptides (AMPs) possess immunomodulatory properties, suggesting their potential to support skin wound healing. Here, we evaluated the proregenerative activity of three recently described AMPs (Clavanin A, Clavanin-MO, and Mastoparan-MO). Human primary dermal fibroblasts (hFibs) were used to determine peptide toxicity and their capacity to induce cell proliferation and migration. Furthermore, mRNA analysis was used to investigate the modulation of genes associated with skin regeneration. Subsequently, the regenerative potential of the peptides was further confirmed using an ex vivo organotypic model of human skin (hOSEC)-based lesion. Our results indicate that the three molecules evaluated in this study have regenerative potential at nontoxic doses (i.e., 200 μM for Clavanin-A and Clavanin-MO, and 6.25 μM for Mastoparan-MO). At these concentrations, all peptides promoted the proliferation and migration of hFibs during in vitro assays. Such processes were accompanied by gene expression signatures related to skin regenerative processes, including significantly higher KI67, HAS2 and CXCR4 mRNA levels induced by Clavanin A and Mastoparan-MO. Such findings translated into significantly accelerated wound healing promoted by both Clavanin A and Mastoparan-MO in hOSEC-based lesions. Overall, the data demonstrate the proregenerative properties of these peptides using human experimental skin models, with Mastoparan-MO and Clavanin A showing much greater potential for inducing wound healing compared to Clavanin-MO. Full article

Human alphaherpesvirus 1 (HSV-1) is a significantly widespread viral pathogen causing recurrent infections that are currently incurable despite available treatment protocols. Studies have highlighted the potential of antimicrobial peptides sourced from Vespula lewisii venom, particularly those belonging to the mastoparan family, as effective against HSV-1. This study aimed to demonstrate the antiviral properties of mastoparans, including mastoparan-L [I⁵, R⁸], mastoparan-MO, and [I⁵, R⁸] mastoparan, against HSV-1. Initially, Vero cell viability was assessed in the presence of these peptides, followed by the determination of antiviral activity, mechanism of action, and dose-response curves through plaque assays. Structural analyses via circular dichroism and nuclear magnetic resonance were conducted, along with evaluating membrane fluidity changes induced by [I⁵, R⁸] mastoparan using fluorescence-labeled lipid vesicles. Cytotoxic assays revealed high cell viability (>80%) at concentrations of 200 µg/mL for mastoparan-L and mastoparan-MO and 50 µg/mL for [I⁵, R⁸] mastoparan. Mastoparan-MO and [I⁵, R⁸] mastoparan exhibited over 80% HSV-1 inhibition, with up to 99% viral replication inhibition, particularly in the early infection stages. Structural analysis indicated an α-helical structure for [I⁵, R⁸] mastoparan, suggesting effective viral particle disruption before cell attachment. Mastoparans present promising prospects for HSV-1 infection control, although further investigation into their mechanisms is warranted. Full article

Biologically active peptides have attracted increasing attention in research on the development of new drugs. Mastoparans, a group of wasp venom linear cationic α-helical peptides, have a variety of biological effects, including mast cell degranulation, activation of protein G, and antimicrobial and anticancer activities. However, the potential hemolytic activity of cationic α-helical peptides greatly limits the clinical applications of mastoparans. Here, we systematically and comprehensively studied the hemolytic activity of mastoparans based on our wasp venom mastoparan family peptide library. The results showed that among 55 mastoparans, 18 had strong hemolytic activity (EC₅₀ ≤ 100 μM), 14 had modest hemolytic activity (100 μM < EC₅₀ ≤ 400 μM) and 23 had little hemolytic activity (EC₅₀ > 400 μM), suggesting functional variation in the molecular diversity of mastoparan family peptides from wasp venom. Based on these data, structure–function relationships were further explored, and, hydrophobicity, but not net charge and amphiphilicity, was found to play a critical role in the hemolytic activity of mastoparans. Combining the reported antimicrobial activity with the present hemolytic activity data, we found that four mastoparan peptides, Parapolybia-MP, Mastoparan-like peptide 12b, Dominulin A and Dominulin B, have promise for applications because of their high antimicrobial activity (MIC ≤ 10 μM) and low hemolytic activity (EC₅₀ ≥ 400 μM). Our research not only identified new leads for the antimicrobial application of mastoparans but also provided a large chemical space to support the molecular design and optimization of mastoparan family peptides with low hemolytic activity regardless of net charge or amphiphilicity. Full article

Wasp stings have become an increasingly serious public health problem because of their high incidence and mortality rates in various countries and regions. Mastoparan family peptides are the most abundant natural peptides in hornet venoms and solitary wasp venom. However, there is a lack of systematic and comprehensive studies on mastoparan family peptides from wasp venoms. In our study, for the first time, we evaluated the molecular diversity of 55 wasp mastoparan family peptides from wasp venoms and divided them into four major subfamilies. Then, we established a wasp peptide library containing all 55 known mastoparan family peptides by chemical synthesis and C-terminal amidation modification, and we systematically evaluated their degranulation activities in two mast cell lines, namely the RBL-2H3 and P815 cell lines. The results showed that among the 55 mastoparans, 35 mastoparans could significantly induce mast cell degranulation, 7 mastoparans had modest mast cell degranulation activity, and 13 mastoparans had little mast cell degranulation activity, suggesting functional variation in mastoparan family peptides from wasp venoms. Structure–function relationship studies found that the composition of amino acids in the hydrophobic face and amidation in the C-terminal region are critical for the degranulation activity of mastoparan family peptides from wasp venoms. Our research will lay a theoretical foundation for studying the mechanism underlying the degranulation activity of wasp mastoparans and provide new evidence to support the molecular design and molecular optimization of natural mastoparan peptides from wasp venoms in the future. Full article

We investigated the antimicrobial activity and membrane disruption modes of the antimicrobial peptide mastoparan-AF against hemolytic Escherichia coli O157:H7. Based on the physicochemical properties, mastoparan-AF may potentially adopt a 3–11 amphipathic helix-type structure, with five to seven nonpolar or hydrophobic amino acid residues forming the hydrophobic face. E. coli O157:H7 and two diarrheagenic E. coli veterinary clinical isolates, which are highly resistant to multiple antibiotics, are sensitive to mastoparan-AF, with minimum inhibitory and bactericidal concentrations (MIC and MBC) ranging from 16 to 32 μg mL⁻¹ for E. coli O157:H7 and four to eight μg mL⁻¹ for the latter two isolates. Mastoparan-AF treatment, which correlates proportionally with membrane permeabilization of the bacteria, may lead to abnormal dents, large perforations or full opening at apical ends (hollow tubes), vesicle budding, and membrane corrugation and invagination forming irregular pits or pores on E. coli O157:H7 surface. In addition, mRNAs of prepromastoparan-AF and prepromastoparan-B share a 5′-poly(A) leader sequence at the 5′-UTR known for the advantage in cap-independent translation. This is the first report about the 3–11 amphipathic helix structure of mastoparans to facilitate membrane interaction. Mastoparan-AF could potentially be employed to combat multiple antibiotic-resistant hemolytic E. coli O157:H7 and other pathogenic E. coli. Full article

Envenomation by animal venoms remains a serious medical and social problem, especially in tropical countries. On the other hand, animal venoms are widely used as a source of biologically active compounds for the development of novel drugs. Numerous derivatives of animal venoms are already used in clinical practice. When analysing the mechanisms of action of animal venoms, attention is usually focused on the main target of the venom’s enzymes and peptides such as neurotoxic, cytotoxic or haemorrhagic effects. In the present review, we would like to draw attention to the “hidden” effects of animal venoms and their derivatives in regard to DNA damage and/or protection against DNA damage. Alkaloids and terpenoids isolated from sponges such as avarol, ingenamine G or variolin B manifest the capability to bind DNA in vitro and produce DNA breaks. Trabectidin, isolated from a sea squirt, also binds and damages DNA. A similar action is possible for peptides isolated from bee and wasp venoms such as mastoparan, melectin and melittin. However, DNA lesions produced by the crude venoms of jellyfish, scorpions, spiders and snakes arise as a consequence of cell membrane damage and the subsequent oxidative stress, whereas certain animal venoms or their components produce a genoprotective effect. Current research data point to the possibility of using animal venoms and their components in the development of various potential therapeutic agents; however, before their possible clinical use the route of injection, molecular target, mechanism of action, exact dosage, possible side effects and other fundamental parameters should be further investigated. Full article

Restrictions on antibiotics are driving the search for alternative feed additives to promote gastrointestinal health and development in broiler chicken production. Proteins including antimicrobial peptides can potentially be applied as alternatives to antibiotics and are one of the most promising alternatives. We investigated whether the addition of MPX to the diet affects the production performance, immune function and the intestinal flora of the caecal contents of broiler chickens. One hundred one-day-old chickens were randomly divided into two groups: control (basal diet) and MPX (20 mg/kg) added to the basal diet. The results indicated that dietary supplementation with MPX improved the performance and immune organ index, decreased the feed conversion ratio, increased the villus length, maintained the normal intestinal morphology and reduced the IL-6 and LITNF mRNA expression levels of inflammation-related genes. In addition, MPX increased the mRNA expression of the digestive enzymes FABP2 and SLC2A5/GLUT5 and the tight junction proteins ZO-1, Claudin-1, Occludin, JAM-2 and MUC2, maintained the intestinal permeability and regulated the intestinal morphology. Moreover, MPX increased the CAT, HMOX1 and SOD1 mRNA expression levels of the antioxidant genes. Furthermore, a 16S rRNA microflora analysis indicated that the abundance of Lactobacillus and Lactococcus in the cecum was increased after addition of MPX at 14 d and 28 d. This study explored the feasibility of using antimicrobial peptides as novel feed additives for broiler chickens and provides a theoretical basis for their application in livestock. Full article

Mastoparan (MP) is an antimicrobial cationic tetradecapeptide with the primary structure INLKALAALAKKIL-NH₂. This amphiphilic α-helical peptide was originally isolated from the venom of the wasp Paravespula lewisii. MP shows a variety of biological activities, such as inhibition of the growth of Gram-positive and Gram-negative bacteria, as well as hemolytic activity and activation of mast cell degranulation. Although MP appears to be toxic, studies have shown that its analogs have a potential therapeutic application as antimicrobial, antiviral and antitumor agents. In the present study we have designed and synthesized several new chimeric mastoparan analogs composed of MP and other biologically active peptides such as galanin, RNA III inhibiting peptide (RIP) or carrying benzimidazole derivatives attached to the ε-amino side group of Lys residue. Next, we compared their antimicrobial activity against three reference bacterial strains and conformational changes induced by membrane-mimic environments using circular dichroism (CD) spectroscopy. A comparative analysis of the relationship between the activity of peptides and the structure, as well as the calculated physicochemical parameters was also carried out. As a result of our structure–activity study, we have found two analogs of MP, MP-RIP and RIP-MP, with interesting properties. These two analogs exhibited a relatively high antibacterial activity against S. aureus compared to the other MP analogs, making them a potentially attractive target for further studies. Moreover, a comparative analysis of the relationship between peptide activity and structure, as well as the calculated physicochemical parameters, may provide information that may be useful in the design of new MP analogs. Full article

This study aimed to develop synergistic therapies to treat superbug infections through the encapsulation of sortase A inhibitors (SrtAIs; trans-chalcone (TC), curcumin (CUR), quercetin (QC), or berberine chloride (BR)) into MCM-41 mesoporous silica nanoparticles (MSNs) or a phosphonate-modified analogue (MCM-41-PO₃⁻) to overcome their poor aqueous solubility. A resazurin-modified minimum inhibitory concentration (MIC) and checkerboard assays, to measure SrtAI synergy in combination with leading antimicrobial peptides (AMPs; pexiganan (PEX), indolicidin (INDO), and [I5, R8] mastoparan (MASTO)), were determined against methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The results demonstrated that the MCM-41 and MCM-41-PO₃⁻ formulations significantly improved the aqueous solubility of each SrtAI. The MICs for SrtAI/MCM-41-PO₃⁻ formulations were lower compared to the SrtAI/MCM-41 formulations against tested bacterial strains, except for the cases of BR/MCM-41 and QC/MCM-41 against P. aeruginosa. Furthermore, the following combinations demonstrated synergy: PEX with TC/MCM-41 (against all strains) or TC/MCM-41-PO₃⁻ (against all strains except P. aeruginosa); PEX with BR/MCM-41 or BR/MCM-41-PO₃⁻ (against MSSA and MRSA); INDO with QC/MCM-41 or QC/MCM-41-PO₃⁻ (against MRSA); and MASTO with CUR/MCM-41 (against E. coli). These combinations also reduced each components’ toxicity against human embryonic kidney cells. In conclusion, MCM-41 MSNs provide a platform to enhance SrtAI solubility and demonstrated antimicrobial synergy with AMPs and reduced toxicity, providing novel superbug treatment opportunities. Full article

The high mortality associated with invasive fungal infections, narrow spectrum of available antifungals, and increasing evolution of antifungal resistance necessitate the development of alternative therapies. Host defense peptides are regarded as the first line of defense against microbial invasion in both vertebrates and invertebrates. In this work, we investigated the effectiveness of four naturally occurring pore-forming antimicrobial peptides (melittin, magainin 2, cecropin A, and mastoparan B) against a panel of clinically relevant pathogens, including Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida glabrata. We present data on the antifungal activities of the four pore-forming peptides, assessed with descriptive statistics, and their cytocompatibility with cultured human cells. Among the four peptides, mastoparan B (MB) displayed potent antifungal activity, whereas cecropin A was the least potent. We show that MB susceptibility of phylogenetically distant non-candida albicans can vary and be described by different intrinsic physicochemical parameters of pore-forming α-helical peptides. These findings have potential therapeutic implications for the design and development of safe antifungal peptide-based drugs. Full article

Antimicrobial peptides are an important class of therapeutic agent used against a wide range of pathogens such as Gram-negative and Gram-positive bacteria, fungi, and viruses. Mastoparan (MpVT) is an α-helix and amphipathic tetradecapeptide obtained from Vespa tropica venom. This peptide exhibits antibacterial activity. In this work, we investigate the effect of amino acid substitutions and deletion of the first three C-terminal residues on the structure–activity relationship. In this in silico study, the predicted structure of MpVT and its analog have characteristic features of linear cationic peptides rich in hydrophobic and basic amino acids without disulfide bonds. The secondary structure and the biological activity of six designed analogs are studied. The biological activity assays show that the substitution of phenylalanine (MpVT1) results in a higher antibacterial activity than that of MpVT without increasing toxicity. The analogs with the first three deleted C-terminal residues showed decreased antibacterial and hemolytic activity. The CD (circular dichroism) spectra of these peptides show a high content α-helical conformation in the presence of 40% 2,2,2-trifluoroethanol (TFE). In conclusion, the first three C-terminal deletions reduced the length of the α-helix, explaining the decreased biological activity. MpVTs show that the hemolytic activity of mastoparan is correlated to mean hydrophobicity and mean hydrophobic moment. The position and spatial arrangement of specific hydrophobic residues on the non-polar face of α-helical AMPs may be crucial for the interaction of AMPs with cell membranes. Full article

We analyzed, for the first time, the major components and biological properties of the venom of Vespa bicolor, a wasp from South China. Using HPLC and SDS-PAGE, combined with LC–MS/MS, MALDI-TOF-MS, and NMR data to analyze V. bicolor venom (VBV), we found that VBV contains three proteins (hyaluronidase A, phospholipase A1 (two isoforms), and antigen 5 protein) with allergenic activity, two unreported proteins (proteins 5 and 6), and two active substances with large quantities (mastoparan-like peptide 12a (Vb-MLP 12a), and 5-hydroxytryptamine (5-HT)). In addition, the antimicrobial activity of VBV was determined, and results showed that it had a significant effect against anaerobic bacteria. The minimum inhibitory concentration and minimum bactericidal concentration for Propionibacterium acnes were 12.5 µg/mL. Unsurprisingly, VBV had strong antioxidant activity because of the abundance of 5-HT. Contrary to other Vespa venom, VBV showed significant anti-inflammatory activity, even at low concentrations (1 µg/mL), and we found that Vb-MLP 12a showed pro-inflammatory activity by promoting the proliferation of RAW 264.7 cells. Cytotoxicity studies showed that VBV had similar antiproliferative effects against all tested tumor cell lines (HepG2, Hela, MCF-7, A549, and SASJ-1), with HepG2 being the most susceptible. Overall, this study on VBV has high clinical importance and promotes the development of Vespa bicolor resources. Full article

Lung cancer has a very low survival rate, and non-small cell lung cancer comprises around 85% of all types of lung cancers. Fluvastatin (FLV) has demonstrated the apoptosis and suppression of tumor-cell proliferation against lung cancer cells in vitro. Drug–peptide nanoconjugates were found to enhance the cytotoxicity of anti-cancer drugs. Thus, the present study aimed to develop a nanocomplex of FLV with mastoparan (MAS), which is a peptide that has membranolytic anti-tumor activity. The nanocomplex of FLV and MAS (MAS-FLV-NC) was prepared and optimized for particle size using Box–Behnken design. The amount of FLV had the highest influence on particle size. While higher levels of FLV and incubation time favored higher particle size, a higher level of sonication time reduced the particle size of MAS-FLV-NC. The optimum formula of MAS-FLV-NC used 1.00 mg of FLV and was prepared with an incubation time of 12.1339 min and a sonication time of 6 min. The resultant particle size was 77.648 nm. The in vitro cell line studies of MAS-FLV-NC, FLV, and MAS were carried out in A549 cells. The IC₅₀ values of MAS-FLV-NC, FLV, and MAS were 18.6 ± 0.9, 58.4 ± 2.8, and 34.3 ± 1.6 µg/mL respectively, showing the enhanced cytotoxicity of MAS-FLV-NC. The apoptotic activity showed that MAS-FLV-NC produced a higher percentage of cells in the late phase, showing a higher apoptotic activity than FLV and MAS. Furthermore, cell cycle arrest in S and Pre G1 phases by MAS-FLV-NC was observed in the cell cycle analysis by flow cytometry. The loss of mitochondrial membrane potential after MAS-FLV-NC treatment was significantly higher than those observed for FLV and MAS. The IL-1β, IL-6, and NF-kB expressions were inhibited, whereas TNF-α, caspase-3, and ROS expressions were enhanced by MAS-FLV-NC treatment. Furthermore, the expression levels of Bax, Bcl-2, and p53 strongly established the enhanced cytotoxic effect of MAS-FLV-NC. The results indicated that MAS-FLV-NC has better cytotoxicity than individual effects of MAS and FLV in A549 cells. Further pre-clinical and clinical studies are needed for developing MAS-FLV-NC to a clinically successful therapeutic approach against lung cancer. Full article

The antibiotic and toxic properties for four synthetic analogs of eumenine mastoparan peptides (EMP) have been tested. These properties were compared to two natural peptides found in the venom of solitary wasps Anterhynchium flavomarginatum micado (natural peptide EMP-AF) and Eumenes rubrofemoratus (natural peptide EMP-ER), respectively. Only EMP-AF-OR showed concentration-dependent growth inhibition against all bacterial species tested. Gram positive species had MIC values of 10 μg/mL for B. subtilis and 25 μg/mL for S. aureus. Gram negative species had MIC values of 25 μg/mL for E. coli and 200 μg/mL for P. aeruginosa. Of the other tested peptides, EMP-ER-D2K2 also showed activity and inhibited growth of Bacillus subtilis in a concentration-dependent manner at 200 μg/mL. Peptide EMP-ER-OR reduced the final density of Escherichia coli and B. subtilis cultures but did not impact their growth kinetics. Peptides EMP-AF-OR, EMP-ER-OR, and EMP-ER-D2K2 showed limited antifungal activity against Candida albicans or Histoplasma capsulatum. The hemolytic activity of the analogs were moderated though reports of the natural peptides, especially EMP-AF-OR, already showed low toxicity against erythrocytes. These results are discussed in the context of the potential influence of oxidized methionine on EMP activity. Full article