Functional characterization of naturally occurring melittin peptide isoforms in two honey bee species, Apis mellifera and Apis cerana

Melittin and phospholipase A2: Promising anti-cancer candidates from bee venom

As the research on cancer-related treatment deepens, integrating traditional therapies with emerging interventions reveals new therapeutic possibilities. Melittin and phospholipase A2, the primary anti-cancer components of bee venom, are currently gaining increasing attention. This article reviews the various formulations of melittin in cancer therapy and its potential applications in clinical treatments. The reviewed formulations include melittin analogs, hydrogels, adenoviruses, fusion toxins, fusion peptides/proteins, conjugates, liposomes, and nanoparticles. The article also explored the collaborative therapeutic effects of melittin with natural products, synthetic drugs, radiotherapy, and gene expression regulatory strategies. Phospholipase A2 plays a key role in bee venom anti-cancer strategy due to its unique biological activity. Using an extensive literature review and the latest scientific results, this paper explores the current state and challenges of this field, with the aim to provide new perspectives that guide future research and potential clinical applications. This will further promote the application of bee venom in cancer therapy.

Ame-miR-1-3p of bee venom reduced cell viability through the AZIN1/OAZ1-ODC1-polyamines pathway and enhanced the defense ability of honeybee (Apis mellifera L.)

Bee venom serves as an essential defensive weapon for bees and also finds application as a medicinal drug. MicroRNAs (miRNAs) serve as critical regulators and have been demonstrated to perform a variety of biological functions. However, the presence of miRNAs in bee venom needs to be confirmed. Therefore, we conducted small RNA sequencing and identified 158 known miRNAs, 15 conserved miRNAs and 4 novel miRNAs. It is noteworthy that ame-miR-1-3p, the most abundant among them, accounted for over a quarter of all miRNA reads. To validate the function of ame-miR-1-3p, we screened 28 candidate target genes using transcriptome sequencing and three target gene prediction software (miRanda, PITA and TargetScan) for ame-miR-1-3p. Subsequently, we employed real-time quantitative reverse transcription PCR (qRT-PCR), Western blot and other technologies to confirm that ame-miR-1-3p inhibits the relative expression of antizyme inhibitor 1 (AZIN1) by targeting the 3' untranslated region (UTR) of AZIN1. This, in turn, caused ODC antizyme 1 (OAZ1) to bind to ornithine decarboxylase 1 (ODC1) and mark ODC1 for proteolytic destruction. The reduction in functional ODC1 ultimately resulted in a decrease in polyamine biosynthesis. Furthermore, we determined that ame-miR-1-3p accelerates cell death through the AZIN1/OAZ1-ODC1-polyamines pathway. Our studies demonstrate that ame-miR-1-3p diminishes cell viability and it may collaborate with sPLA2 to enhance the defence capabilities of honeybees (Apis mellifera L.). Collectively, these data further elucidate the defence mechanism of bee venom and expand the potential applications of bee venom in medical treatment.

Polypeptides from traditional Chinese medicine: Comprehensive review of perspective towards cancer management

Cancer has always been a focus of global attention, and the difficulty of treatment and poor prognosis have always plagued humanity. Conventional chemotherapeutics and treatment with synthetic disciplines will cause adverse side effects and drug resistance. Therefore, searching for a safe, valid, and clinically effective drug is necessary. At present, some natural compounds have proved to have the potential to fight cancer. Polypeptides obtained from traditional Chinese medicine are good anti-cancer ingredients. The anticancer activity has been fully demonstrated in vivo and in vitro. However, most of the functional studies on traditional Chinese medicine polypeptides are at the stage of basic experimental research, and fewer of them have been applied to clinical trials. Hence, this review mainly discusses the chemical structure, extraction, separation and purification methods, the anti-cancer mechanism, and structure-activity relationships of traditional Chinese medicine polypeptides. It provides theoretical support for strengthening the rapid separation and purification and the overall efficacy and mechanism of action, as well as the industrialization and clinical application of traditional Chinese medicine polypeptides.

Anti-Herpes Simplex Virus and Anti-Inflammatory Activities of the Melittin Peptides Derived from Apis mellifera and Apis florea Venom

Herpes simplex virus (HSV) is known to cause cold sores and various diseases in humans. Importantly, HSV infection can develop latent and recurrent infections, and it is also known to cause inflammation. These infections are difficult to control, and effective treatment of the disease remains a challenge. Thus, the search for new antiviral and anti-inflammatory agents is a necessity. Melittin is a major peptide that is present in the venom of the honeybee. It possesses a number of pharmacological properties. In this study, the effects of the melittin peptides from A. mellifera (MEL-AM) and A. florea (MEL-AF) against HSV-1 and HSV-2 were evaluated at different stages during the viral multiplication cycle in an attempt to define the mode of antiviral action using plaque reduction and virucidal assays. The results revealed a new finding that melittin at 5 µg/mL demonstrated the highest inhibitory effect on HSV through the direct inactivation of viral particles, and MEL-AF displayed a greater virucidal activity. Moreover, melittin was also observed to interfere with the process of HSV attachment to the host cells. MEL-AM exhibited anti-HSV-1 and anti-HSV-2 effects with EC50 values of 4.90 ± 0.15 and 4.39 ± 0.20 µg/mL, while MEL-AF demonstrated EC50 values of 4.47 ± 0.21 and 3.95 ± 0.61 µg/mL against HSV-1 and HSV-2, respectively. However, non-cytotoxic concentrations of both types of melittin produced only slight degrees of HSV-1 and HSV-2 inhibition after viral attachment, but melittin at 5 µg/mL was able to reduce the plaque size of HSV-2 when compared to the untreated group. In addition, MEL-AM and MEL-AF also exhibited anti-inflammatory activity via the inhibition of nitric oxide production in LPS-stimulated RAW 264.7 macrophage cells, and they were also found to down-regulate the expressions of the iNOS, COX-2 and IL-6 genes. The highest inhibition of IL-6 mRNA expression was found after treatment with 10 µg/mL of MEL-AM and MEL-AF. Therefore, melittin peptides have displayed strong potential to be used as an alternative treatment for HSV infection and inflammatory diseases in the future.

Antiviral attributes of bee venom as a possible therapeutic approach against SARS-CoV-2 infection

The unprecedented scale of the SARS-CoV-2 pandemic has driven considerable investigation into novel antiviral treatments since effective vaccination strategies cannot completely eradicate the virus. Apitherapy describes the medicinal use of bee venom, which may be an effective treatment against SARS-CoV-2 infection. Bee venom contains chemicals that are antimicrobial and stimulate the immune system to counteract viral load. The present review focuses on the use of bee venom as a possible treatment for COVID-19 and reviews studies on the pharmacodynamics of bee venom.

An Updated Review Summarizing the Anticancer Efficacy of Melittin from Bee Venom in Several Models of Human Cancers

Apitherapy (using bee products) has gained broad recognition in cancer therapeutics globally. Honeybee venom has a broad range of biological potential, and its utilization is rapidly emerging in apitherapy. Bee products have significant potential to strengthen the immune system and improve human health. Thus, this review is targeted toward recapitulating the chemo-preventive potential of melittin (MEL), which constitutes a substantial portion of honeybee venom. Honeybee venom (apitoxin) is produced in the venom gland of the honeybee abdomen, and adult bees utilize it as a primary colony defense mechanism. Apitoxin comprises numerous biologically active compounds, including peptides, enzymes, amines, amino acids, phospholipids, minerals, carbohydrates, and volatile components. We are mainly focused on exploring the potential of melittin (a peptide component) of bee venom that has shown promising potential in the treatment of several human cancers, including breast, stomach, lung, prostate, ovary, kidney, colon, gastric, esophageal, cervical cancers, melanoma, osteosarcoma, and hepatocellular carcinoma. This review has summarized all potential studies related to the anticancerous efficacy of melittin (apitoxin), its formulations, conjugates, and nano-formulations against several human carcinomas, which would further pave the way for future researchers in developing potent drugs for cancer management.

Molecularly Imprinted Chalcone-Branched Polyimide-Based Chemosensors with Stripe Nanopatterns for the Detection of Melittin

In this study, a chalcone-branched polyimide (CB-PI) was synthesized by the Steglich esterification reaction for selective recognition of the toxic peptide melittin (MEL). MEL was immobilized on a nanopatterned poly(dimethylsiloxane) (PDMS) mold using a conventional surface modification technique to increase binding sites. A stripe-nanopatterned thin CB-PI film was formed on a quartz crystal (QC) substrate by simultaneously performing microcontact printing and ultraviolet (UV) light dimerization using a MEL-immobilized mold. The surface morphology changes and dimensions of the molecularly imprinted polymer (MIP) films with stripe nanopatterns (S-MIP) were analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The sensing signals (Δf and Qe) of the S-MIP sensor were investigated upon adsorption in a 100-μL dilute plasma solution containing 30 μg/mL MEL, and its reproducibility, reuse, stability, and durability were investigated. The S-MIP sensor showed high sensitivity (5.49 mL/mg) and coefficient of determination (R2 = 0.999), and the detection limit (LOD) and the quantification limit (LOQ) were determined as 0.3 and 1.1 μg/mL, respectively. In addition, the selectivity coefficients (k*) calculated from the selectivity tests were 2.7-5.7, 2.1-4.3, and 2.8-4.6 for bovine serum albumin (BSA), immunoglobulin G (IgG), and apamin (APA), respectively. Our results indicate that the nanopatterned MIP sensors based on CB-PI demonstrate great potential as a sensing tool for the quantitative analysis of biomolecules.

Wings and stings: Hymenoptera on vacation

Traveling to different regions, one might encounter a species to which they have a known allergy, or other related and unrelated species. A first-time systemic reaction can occur while on vacation, even in those with previous asymptomatic stings. Three main groups of Hymenoptera are responsible for most sting reactions. Honey bee species are virtually identical around the world. Among social wasps (family Vespidae), the yellowjacket (genus Vespula and Dolichovespula) and hornet (genus Vespa) venoms have almost complete cross-reactivity, whereas paper wasp (genus Polistes) venoms show only partial cross-reactivity with other vespid venoms. Venom immunotherapy (VIT) confers 80% to 95% protection against related insects, though isolated species of paper wasps and yellowjackets exist in every country that may be distinct from the ones at home. Those allergic to imported fire ants (genus Solenopsis) in the United States should not react to other ant species around the world. Stinging ants belong to several unrelated subfamilies in different geographic regions, which do not have cross-reactive venom. The chances of encountering specific species of Hymenoptera at a traveler's destination vary by location, planned activities, and season. In this article, we discuss special considerations for traveling, including distribution of stinging insects around the world, risk factors for more severe reactions, ways to prepare for a trip, and when allergist examination or treatment may be helpful before travel.

Antibiotics-induced changes in intestinal bacteria result in the sensitivity of honey bee to virus

Antibiotics are omnipresent in the environment due to their widespread use, and they have wide-ranging negative impacts on organisms. Virus resistance differs substantially between domesticated Apis mellifera and wild Apis cerana, although both are commonly raised in China. Here, we investigated whether antibiotics can increase the sensitivity of honey bees to viral infection using the Israeli acute paralysis virus (IAPV) and tetracycline as representative virus and antibiotic. Although IAPV multiplied to lower levels in A. cerana than A. mellifera, resulting in decreased mortality (P < 0.01), there was no significant difference in immune responses to viral infection between the two species. Adult worker bees (A. cerana and A. mellifera) were treated with or without tetracycline to demonstrate the prominent role of gut microbiota against viral infection, and found Lactobacillus played a vital antiviral role in A. cerana. In A. cerana but not A. mellifera, tetracycline treatment reduced clearly bee survival and increased susceptibility to IAPV infection (P < 0.01). Our findings revealed that long-term antibiotic treatment in A. mellifera had altered the native gut microbiome and promoted the sensitivity to viral infection. We highlight the effects of antibiotics exposure on resistance to microbial and viral infection.

Lima B, Araújo AAS, de Albuquerque-Junior RLC, Gramacho KP, Padilha FF, da Costa LP, Severino P, Cardoso JC, Souto EB, Gomes MZ. Africanized Bee Venom (Apis mellifera Linnaeus): Neuroprotective Effects in a Parkinson's Disease Mouse Model Induced by 6-hydroxydopamine

This study evaluated the neuroprotective effects of the Africanized bee venom (BV) and its mechanisms of action after 6-hydroxydopamine-(6-OHDA)-induced lesion in a mice model. Prior to BV treatment, mice received intrastriatal microinjections of 6-OHDA (no induced dopaminergic neuronal death) or ascorbate saline (as a control). BV was administered subcutaneously at different dosages (0.01, 0.05 or 0.1 mg·Kg^-1) once every two days over a period of 3 weeks. The open field test was carried out, together with the immunohistochemical and histopathological analysis. The chemical composition of BV was also assessed, identifying the highest concentrations of apamin, phospholipase A₂ and melittin. In the behavioral evaluation, the BV (0.1 mg·Kg^-1) counteracted the 6-OHDA-induced decrease in crossings and rearing. 6-OHDA caused loss of dopaminergic cell bodies in the substantia nigra pars compacta and fibers in striatum (STR). Mice that received 0.01 mg·Kg^-1 showed significant increase in the mean survival of dopaminergic cell bodies. Increased astrocytic infiltration occurred in the STR of 6-OHDA injected mice, differently from those of the groups treated with BV. The results suggested that Africanized BV has neuroprotective activity in an animal model of Parkinson's disease.

Comparative Study of Antimicrobial Properties of Bee Venom Extracts and Melittins of Honey Bees

Bee venom (BV), or apitoxin, is a complex substance produced by a gland in the abdominal cavity of bees. The main component of BV is melittin, which is a largely studied substance due to its biological properties. To date, the most well-known bee venom and melittin are derived from domesticated honey bees, while venom and melittin derived from wild honey bees have been under-investigated. Hence, this study primarily reports the antimicrobial activities of bee venom and synthetic melittin derived from four different honey bee species (Apis mellifera, A. cerana, A. dorsata, and A. florea) in Thailand. All the bee venom extracts and melittins showed more robust antibacterial activities against Gram-positive (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, S. aureus MRSA, and S. epidermidis) than Gram-negative bacteria (Escherichia coli, Klebsiella pneuminiae, and Salmonella typhimurium) or a fungus (Candida albicans), while the synthetic melittins also have antimicrobial activity at higher concentrations than the bee venom extract. Furthermore, the A. cerana venom extract showed the highest activity against the tested bacteria, followed by A. mellifera, A. florea, and A. dorsata. Therefore, A. cerana venom may be further developed for use in medical applications as a potential alternative agent against Gram-positive bacteria and antibiotic-resistant bacteria.

A Review of Honeybee Venom Allergens and Allergenicity

Honeybee venom is a source of proteins with allergenic properties which can result in in various symptoms, ranging from local reactions through to systematic life-threatening anaphylaxis, or even death. According to the World Allergy Organization (WAO), honeybee venom allergy is one of the most common causes of anaphylaxis. Among the proteins present in honeybee venom, 12 protein fractions were registered by the World Health Organization’s Allergen Nomenclature Sub-Committee (WHO/IUIS) as allergenic. Most of them are highly immunogenic glycoproteins that cross-react with IgE and, as a consequence, may give false positive results in allergy diagnosis. Allergenic fractions are different in terms of molecular weight and biological activity. Eight of these allergenic fractions have also been identified in honey. This explains frequent adverse reactions after consuming honey in people allergic to venom and sheds new light on the causes of allergic symptoms in some individuals after honey consumption. At the same time, it also indicates the possibility of using honey as a natural source of allergen in specific immunotherapy.

Beehive Products as Antibacterial Agents: A Review

Honeybees are one of the most marvelous and economically beneficial insects. As pollinators, they play a vital role in every aspect of the ecosystem. Beehive products have been used for thousands of years in many cultures for the treatment of various diseases. Their healing properties have been documented in many religious texts like the Noble Quran and the Holy Bible. Honey, bee venom, propolis, pollen and royal jelly all demonstrated a richness in their bioactive compounds which make them effective against a variety of bacterial strains. Furthermore, many studies showed that honey and bee venom work as powerful antibacterial agents against a wide range of bacteria including life-threatening bacteria. Several reports documented the biological activities of honeybee products but none of them emphasized on the antibacterial activity of all beehive products. Therefore, this review aims to highlight the antibacterial activity of honey, bee venom, propolis, pollen and royal jelly, that are produced by honeybees.

Chemical Profiling and Antimicrobial Properties of Honey Bee (Apis mellifera L.) Venom

The incidence of antibiotic resistance in pathogenic bacteria has become an alarming clinical and social problem. Therefore, the demand for alternative antimicrobial compounds has increased. In this study, a chemical profile of honey bee (Apis mellifera L.) venom (HBV) has been determined by HPLC and FTIR-ATR spectroscopy, and tested for antibacterial activity, as well as efficiency with regard to conventional antibiotics. The investigated HBV was of high quality with melittin and total protein contents of 70.10 ± 7.01%, and 84.44 ± 3.12 g/100 g, respectively. The purity of HBV was confirmed by FTIR-ATR spectral profiling, which revealed a unique pattern of absorption bands that are characteristic of its major fractions. In addition, HBV showed a broad spectrum of activity against all three tested biomasses of potentially pathogenic Gram-positive and Gram-negative bacteria with MIC values ranging between 12.5 and 200 µg/mL, and MBC between 12.5 and 400 µg/mL. When compared to conventional antibiotics, HBV (400 µg) showed up to 27.8% efficiency of tetracycline (30 µg), 52.2% erythromycin (15 µg), 21.2% ciprofloxacin (5 µg), and 34.6% of ampicillin-sulbactam (20 µg). The overall results demonstrate the therapeutic potential of the analyzed HBV.

Antimicrobial Properties of Apis mellifera's Bee Venom

Bee venom (BV) is a rich source of secondary metabolites from honeybees (Apis mellifera L.). It contains a variety of bioactive ingredients including peptides, proteins, enzymes, and volatile metabolites. The compounds contribute to the venom’s observed biological functions as per its anti-inflammatory and anticancer effects. The antimicrobial action of BV has been shown in vitro and in vivo experiments against bacteria, viruses, and fungi. The synergistic therapeutic interactions of BV with antibiotics has been reported. The synergistic effect contributes to a decrease in the loading and maintenance dosage, a decrease in the side effects of chemotherapy, and a decrease in drug resistance. To our knowledge, there have been no reviews on the impact of BV and its antimicrobial constituents thus far. The purpose of this review is to address the antimicrobial properties of BV and its compounds.

Synergistic antimicrobial activity of melittin with clindamycin on the expression of encoding exfoliative toxin in Staphylococcus aureus

Staphylococcus aureus is an opportunistic human pathogens, with the ability to produce a series of virulence factors that contribute to the severity of infections. Exfoliative toxins (ETs) are one of the important virulence factors that participating in staphylococcal scalded skin syndrome. Melittin has different biological activities, comprising of antiviral, broad spectrum antibacterial, antiprotozoal, antifungal and anti-inflammatory effects. Twelve clinical isolates of methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) were obtained from wound infection in the burn patients. The MIC plus three sub-inhibitory concentrations (I, II and III) of clindamycin and melittin were tested. Next, the synergistic effects of melittin and clindamycin were evaluated using the broth microdilution checkerboard assay. The detection of exfoliative toxin A and B genes were examined by PCR method. Then the effects of sub-MIC melittin on the expression levels of eta and etb were assessed by quantitative real-time PCR (qRT-PCR) assay. Melittin MIC values against MRSA and MSSA planktonic cells were 0.25-0.5 and 0.25-1 μg/ml, respectively. The clindamycin MIC values against MRSA and MSSA were between 0.5 and 8 μg/ml and 0.5-2 μg/ml, respectively. The results of the time-kill kinetics assay (3.5log₁₀ and 3log₁₀) against MSSA and MRSA planktonic cells were determined within 24 h using melittin. The mean expression of eta in MRSA and MSSA was significantly downregulated to approximately 3.5 and 4 fold, respectively. Moreover, the mean expression of etb in MRSA and MSSA were significantly downregulated to approximately 2.5 and 3 fold, respectively. Hemolytic assay showed that the extracted melittin indicates a strong hemolytic activity (HD₅₀ = 2 μg/ml). Melittin at 0.5 μg/ml induced cell lysis and stimulated the formation of vesicles in S. aureus strains. Melittin could reduce the expression of eta and etb as encoding exfoliative toxin A and B genes. This component appears to be a good candidate for the treatment of MRSA and MSSA strains. So, melittin in combination with clindamycin can be classified as a complementary treatment of wound infections in burn patients.

Synergistic activity of melittin with mupirocin: A study against methicillin-resistant S. Aureus (MRSA) and methicillin-susceptible S. Aureus (MSSA) isolates

Methicillin-Resistant Staphylococcus aureus (MRSA) biofilms are involved in various nosocomial infections, being in the limelight of academic research. The current study aimed to determine the antimicrobial effects of melittin on planktonic and biofilm forms of S. aureus. Following the identification of MRSA and SCCmec types (using PCR method), Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and fractional inhibitory concentration index (FICi), for melittin and mupirocin were determined by broth microdilution assay. Melittin anti-biofilm activity was determined, using a microtiter-plate test (MtP) and scanning electron microscope (SEM) methods. The quorum sensing inhibitory activity of ½ MIC melittin was examined using a quantitative real-time RT-PCR method, and melittin cytotoxicity on Vero cells was examined by tetrazolium-based colorimetric (MTT) test. The Results of our study showed that Geometric means of MIC values of the melittin and mupirocin were 4.4 and 14.22 μg/ml respectively. The geometric mean of the FICi for both melittin-mupirocin was 0.75. No S. aureus biofilm was formed and hld gene (as a biofilm regulator) expression down-regulated. It seems that melittin can be useful in the treatment of S. aureus infections (especially MRSA) by reducing the hld expression. Furthermore, synergistic growth-inhibitory effects of mupirocin with melittin could be considered as a promising approach in the treatment of MRSA isolates.

Balancing Selection Drives the Maintenance of Genetic Variation in Drosophila Antimicrobial Peptides

Genes involved in immune defense against pathogens provide some of the most well-known examples of both directional and balancing selection. Antimicrobial peptides (AMPs) are innate immune effector genes, playing a key role in pathogen clearance in many species, including Drosophila. Conflicting lines of evidence have suggested that AMPs may be under directional, balancing, or purifying selection. Here, we use both a linear model and control-gene-based approach to show that balancing selection is an important force shaping AMP diversity in Drosophila. In Drosophila melanogaster, this is most clearly observed in ancestral African populations. Furthermore, the signature of balancing selection is even more striking once background selection has been accounted for. Balancing selection also acts on AMPs in Drosophila mauritiana, an isolated island endemic separated from D. melanogaster by about 4 Myr of evolution. This suggests that balancing selection may be broadly acting to maintain adaptive diversity in Drosophila AMPs, as has been found in other taxa.

Anti-Tumor Effects of Melittin and Its Potential Applications in Clinic

Melittin, a major component of bee venom, is a water-soluble toxic peptide of which a various biological effects have been identified to be useful in anti-tumor therapy. In addition, Melittin also has anti-parasitic, anti-bacterial, anti-viral, and anti-inflammatory activities. Therefore, it is a very attractive therapeutic candidate for human diseases. However, melittin induces extensive hemolysis, a severe side effect that dampens its future development and clinical application. Thus, studies of melittin derivatives and new drug delivery systems have been conducted to explore approaches for optimizing the efficacy of this compound, while reducing its toxicity. A number of reviews have focused on each side, respectively. In this review, we summarize the research progress on the anti-tumor effects of melittin and its derivatives, and discuss its future potential clinical applications.

Effects of three common pesticides on survival, food consumption and midgut bacterial communities of adult workers Apis cerana and Apis mellifera

The acute and chronic toxicity of 3 common pesticides, namely, amitraz, chlorpyrifos and dimethoate, were tested in Apis mellifera and Apis cerana. Acute oral toxicity LC₅₀ values were calculated after 24 h of exposure to contaminated syrup, and chronic toxicity was tested after 15 days of exposure to 2 sublethal concentrations of pesticides. The toxicity of the tested pesticides to A. mellifera and A. cerana decreased in the order of dimethoate > chlorpyrifos > amitraz. A. mellifera was slightly more sensitive to chlorpyrifos and dimethoate than A. cerana, while A. cerana was more sensitive to amitraz than A. mellifera. Chronic toxicity tests showed that 1.0 mg/L dimethoate reduced the survival of the two bee species and the food consumption of A. mellifera, while 1.0 mg/L amitraz and 1.0 mg/L chlorpyrifos did not affect the survival or food consumption of the two bee species. The treatment of syrup with amitraz at a concentration equal to 1/10th of the LC₅₀ value did not affect the survival of or diet consumption by A. mellifera and A. cerana; however, chlorpyrifos and dimethoate at concentrations equal to 1/10th of their respective LC₅₀ values affected the survival of A. cerana. Furthermore, intestinal bacterial communities were identified using high-throughput sequencing targeting the V3V4 regions of the 16S rDNA gene. All major honey bee intestinal bacterial phyla, including Proteobacteria (62.84%), Firmicutes (34.04%), and Bacteroidetes (2.02%), were detected. There was a significant difference in the microbiota species richness of the two species after 15 days; however, after 30 days, no significant differences were found in the species diversity and richness between A. cerana and A. mellifera exposed to 1.0 mg/L amitraz and 1.0 mg/L chlorpyrifos. Overall, our results confirm that acute toxicity values are valuable for evaluating the chronic toxicity of these pesticides to honey bees.

Melittin Inhibition and Eradication Activity for Resistant Polymicrobial Biofilm Isolated from a Dairy Industry after Disinfection

The emerging concern about the increase of antibiotic resistance and associated biofilm has encouraged scientists to look for alternative antibiotics such as antimicrobial peptides (AMPs). This study evaluated the ability of melittin to act as an antibacterial biofilm inhibitor and biofilm remover considering isolates from dairy industry. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibitory concentrations (MBICs), and biofilm removal activities were studied in polymicrobial biofilms produced from isolates. MIC and MBC were set at 1–3 µg/mL and 25–50 µg/mL for Gram-positive and Gram-negative bacteria, respectively. Results demonstrated a good MBIC reaching 85% inhibition ability and a good activity and better penetration in deeper layers against the mixed preformed biofilm, thereby increasing its activity against all isolates also at the lowest tested concentrations. Melittin showed interesting characteristics suggesting its potential to act as an antimicrobial agent for polymicrobial biofilm from dairy industry even in environmental isolates.

Chinese Medicine Protein and Peptide in Gene and Cell Therapy

The success of gene and cell therapy in clinic during the past two decades as well as our expanding ability to manipulate these biomaterials are leading to new therapeutic options for a wide range of inherited and acquired diseases. Combining conventional therapies with this emerging field is a promising strategy to treat those previously-thought untreatable diseases. Traditional Chinese medicine (TCM) has evolved for thousands of years in China and still plays an important role in human health. As part of the active ingredients of TCM, proteins and peptides have attracted long-term enthusiasm of researchers. More recently, they have been utilized in gene and cell therapy, resulting in promising novel strategies to treat both cancer and non-cancer diseases. This manuscript presents a critical review on this field, accompanied with perspectives on the challenges and new directions for future research in this emerging frontier.

Antioxidant activity and irritation property of venoms from Apis species

Pharmacological effects of bee venom has been reported, however, it has been restricted to the bee venom collected from European honey bee (Apis mellifera). The aim of the present study was to compare the antioxidant activities and irritation properties of venoms collected from four different Apis species in Thailand, which includes Apis cerena (Asian cavity nesting honeybee), Apis florea (dwarf honeybee), Apis dorsata (giant honeybee), and A. mellifera. Melittin content of each bee venom extracts was investigated by using high-performance liquid chromatography. Ferric reducing antioxidant power, 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), and 1, 1-diphenyl-2-picrylhydrazyl assay were used to determine the antioxidant activity, whereas, hen's egg test chorioallantoic membrane assay was used to determine the irritation property of each bee venom extracts. Melittin was the major constituent in all bee venom extracts. The melittin content in A. dorsata, A. mellifera, A. florea, and A. cerena were 95.8 ± 3.2%, 76.5 ± 1.9%, 66.3 ± 8.6%, and 56.8 ± 1.8%, respectively. Bee venom extract from A. dorsata possessed the highest antioxidant activity with the inhibition of 41.1 ± 2.2% against DPPH, Trolox equivalent antioxidant capacity of 10.21 ± 0.74 mM Trolox/mg and equivalent concentration (EC₁) of 0.35 ± 0.02 mM FeSO₄/mg. Bee venom extract from A. mellifera exhibited the highest irritation, followed by A. cerena, A. dorsata, and A. florea, respectively. Melittin was the compound responsible for the irritation property of bee venom extracts since it could induce severe irritation (irritation score was 13.7 ± 0.5, at the concentration of 2 mg/ml). The extract from A. dorsata which possessed the highest antioxidant activity showed no irritation up to the concentration of 0.1 mg/ml. Therefore, bee venom extract from A. dorsata at the concentration not more than 0.1 mg/ml would be suggested for using as cosmetic ingredients since it possessed the highest antioxidant activity with no irritation. This study is the first report to compare the bee venom extracts from different Apis species and display their potential application of bee venom extracts in cosmetic products.

Melittin, a major peptide component of bee venom, and its conjugates in cancer therapy

Melittin (MEL), a major peptide component of bee venom, is an attractive candidate for cancer therapy. This agent has shown a variety of anti-cancer effects in preclinical cell culture and animal model systems. Despite a convincing efficacy data against variety of cancers, its applicability to humans has met with challenges due to several issues including its non-specific cytotoxicity, degradation and hemolytic activity. Several optimization approaches including utilization of nanoparticle based delivery of MEL have been utilized to circumvent the issues. Here, we summarize the current understanding of the anticancer effects of bee venom and MEL on different kinds of cancers. Further, we also present the available information for the possible mechanism of action of bee venom and/or MEL.

Melittin, a honeybee venom‑derived antimicrobial peptide, may target methicillin‑resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is difficult to treat using available antibiotic agents. Honeybee venom has been widely used as an oriental treatment for several inflammatory diseases and bacterial infections. The venom contains predominantly biologically active compounds, however, the therapeutic effects of such materials when used to treat MRSA infections have not been investigated extensively. The present study evaluated bee venom and its principal active component, melittin, in terms of their antibacterial activities and in vivo protection against MRSA infections. In vitro, bee venom and melittin exhibited comparable levels of antibacterial activity, which was more marked against MRSA strains, compared with other Gram-positive bacteria. When MRSA-infected mice were treated with bee venom or melittin, only the latter animals were successfully rescued from MRSA- induced bacteraemia or exhibited recovery from MRSA-infected skin wounds. Together, the data of the present study demonstrated for the first time, to the best of our knowledge, that melittin may be used as a promising antimicrobial agent to enhance the healing of MRSA-induced wounds.

Pharmacological synergism of bee venom and melittin with antibiotics and plant secondary metabolites against multi-drug resistant microbial pathogens

The goal of this study was to investigate the antimicrobial activity of bee venom and its main component, melittin, alone or in two-drug and three-drug combinations with antibiotics (vancomycin, oxacillin, and amikacin) or antimicrobial plant secondary metabolites (carvacrol, benzyl isothiocyanate, the alkaloids sanguinarine and berberine) against drug-sensitive and antibiotic-resistant microbial pathogens. The secondary metabolites were selected corresponding to the molecular targets to which they are directed, being different from those of melittin and the antibiotics. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were evaluated by the standard broth microdilution method, while synergistic or additive interactions were assessed by checkerboard dilution and time-kill curve assays. Bee venom and melittin exhibited a broad spectrum of antibacterial activity against 51 strains of both Gram-positive and Gram-negative bacteria with strong anti-MRSA and anti-VRE activity (MIC values between 6 and 800 µg/ml). Moreover, bee venom and melittin showed significant antifungal activity (MIC values between 30 and 100 µg/ml). Carvacrol displayed bactericidal activity, while BITC exhibited bacteriostatic activity against all MRSA and VRE strains tested (reference strains and clinical isolates), both compounds showed a remarkable fungicidal activity with minimum fungicidal concentration (MFC) values between 30 and 200 µg/ml. The DNA intercalating alkaloid sanguinarine showed bactericidal activity against MRSA NCTC 10442 (MBC 20 µg/ml), while berberine exhibited bacteriostatic activity against MRSA NCTC 10442 (MIC 40 µg/ml). Checkerboard dilution tests mostly revealed synergism of two-drug combinations against all the tested microorganisms with FIC indexes between 0.24 and 0.50, except for rapidly growing mycobacteria in which combinations exerted an additive effect (FICI = 0.75-1). In time-kill assays all three-drug combinations exhibited a powerful bactericidal synergistic effect against MRSA NCTC 10442, VRE ATCC 51299, and E. coli ATCC 25922 with a reduction of more than 3log10 in the colony count after 24 h. Our findings suggest that bee venom and melittin synergistically enhanced the bactericidal effect of several antimicrobial agents when applied in combination especially when the drugs affect several and differing molecular targets. These results could lead to the development of novel or complementary antibacterial drugs against MDR pathogens.

In vivo efficacy of anuran trypsin inhibitory peptides against staphylococcal skin infection and the impact of peptide cyclization

Staphylococcus aureus is a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weak in vitro inhibitory activities against S. aureus, but several had strong antibacterial activities against S. aureus in an in vivo murine wound infection model. pYR, an immunomodulatory peptide from Rana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg(-1). Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen.

Uncovering the novel characteristics of Asian honey bee, Apis cerana, by whole genome sequencing

Background

The honey bee is an important model system for increasing understanding of molecular and neural mechanisms underlying social behaviors relevant to the agricultural industry and basic science. The western honey bee, Apis mellifera, has served as a model species, and its genome sequence has been published. In contrast, the genome of the Asian honey bee, Apis cerana, has not yet been sequenced. A. cerana has been raised in Asian countries for thousands of years and has brought considerable economic benefits to the apicultural industry. A cerana has divergent biological traits compared to A. mellifera and it has played a key role in maintaining biodiversity in eastern and southern Asia. Here we report the first whole genome sequence of A. cerana.

Results

Using de novo assembly methods, we produced a 238 Mbp draft of the A. cerana genome and generated 10,651 genes. A.cerana-specific genes were analyzed to better understand the novel characteristics of this honey bee species. Seventy-two percent of the A. cerana-specific genes had more than one GO term, and 1,696 enzymes were categorized into 125 pathways. Genes involved in chemoreception and immunity were carefully identified and compared to those from other sequenced insect models. These included 10 gustatory receptors, 119 odorant receptors, 10 ionotropic receptors, and 160 immune-related genes.

Conclusions

This first report of the whole genome sequence of A. cerana provides resources for comparative sociogenomics, especially in the field of social insect communication. These important tools will contribute to a better understanding of the complex behaviors and natural biology of the Asian honey bee and to anticipate its future evolutionary trajectory.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-16-1) contains supplementary material, which is available to authorized users.

In vitro potential of Lycosin-I as an alternative antimicrobial drug for treatment of multidrug-resistant Acinetobacter baumannii infections

The resistance of multidrug-resistant Acinetobacter baumannii (MDRAB) isolates to most traditional antibiotics results in huge challenges for infection therapy. We investigated the in vitro activities of both l- and d-lycosin-I against MDRAB. These two compounds displayed high antibacterial activities and rapid bactericidal effects against MDRAB. Moreover, the compounds retained their activity even at high salt (Mg(2+) or Ca(2+)) concentrations. These results demonstrate the potential of lycosin-I to be developed as a new antibiotic.