Galleria Mellonella Larvae Research Articles

Repurposed Anti-Multiple Sclerosis Drug Fty720 Targets Carbapenem-Resistant Acinetobacter baumannii via Multiple Pathways.

Bacterial antimicrobial resistance (AMR), particularly multidrug resistance (MDR) in gram-negative bacterial strains, has emerged as a formidable challenge of substantial consequence, necessitating an urgent pursuit of a sustainable and efficacious strategic response. Repurposing nonantibiotic drugs as potential antibiotics or antibiotic adjuvants is a valuable approach to targeting MDR bacteria. A total of 1,750 FDA-approved drugs (APExBIO, USA) were screened to test their antimicrobial activities against MDR bacteria using the broth microdilution method according to the standard of the Clinical and Laboratory Standards Institute (CLSI). Microscale thermophoresis (MST) analysis was performed to detect the Fty720-LPS interactions. Fty720-indcued lipid changes were measured by untargeted lipidomic analysis. Isothermal titration calorimetry (ITC) analysis was used to determine the Fty720-lipid binding affinities. DNA degradation was assessed via agarose gel electrophoresis with ethidium bromide (EB) staining and visualized using a gel imaging system. Galleria mellonella larvae infection model and Mouse peritonitis infection models were used to evaluated the antibacterial ability of Fty720 in vivo. In this study, we identified Fty720, a pharmaceutical agent for treating multiple sclerosis, as a potent inhibitor of carbapenem-resistant Acinetobacter baumannii (CRAB). We demonstrated that Fty720 exerts antibacterial effects through multiple strategies, including disruption of the structural integrity of the membranes by interacting with LPS and glycerophospholipids, as well as degradation of bacterial DNA. Furthermore, through judicious structural modification, the pivotal role of the positively charged moiety (NH2) in Fty720's antibacterial activity was substantiated. Intriguingly, the translation of Fty720's antibacterial efficacy was demonstrated in vivo, substantiating its pronounced influence on elevating survival rates among models afflicted with MDR gram-negative bacterial infections. Fty720 targets CRAB via multiple pathways, including disruption of outer and inner membrane integrity and DNA degradation. This investigation unveils the multifaceted antibacterial mechanisms of Fty720 while concurrently delineating a prospective therapeutic avenue to counteract MDR gram-negative bacterial strains.

Inhibition of Pseudomonas aeruginosa Carbonic Anhydrases, Exploring Ciprofloxacin Functionalization Toward New Antibacterial Agents: An In-Depth Multidisciplinary Study.

Ciprofloxacin (CPX) is one of the most employed antibiotics in clinics to date. However, the rise of drug-resistant bacteria is dramatically impairing its efficacy, especially against life-threatening pathogens, such as Pseudomonas aeruginosa. This Gram-negative bacterium is an opportunistic pathogen, often infecting immuno-compromised patients with severe or fatal outcomes. The evidence of the possibility of exploiting Carbonic Anhydrase (CA, EC: 4.2.1.1) enzymes as pharmacological targets along with their role in P. aeruginosa virulence inspired the derivatization of CPX with peculiar CA-inhibiting chemotypes. Thus, a large library of CPX derivatives was synthesized and tested on a panel of bacterial CAs and human isoenzymes I and II. Selected derivatives were evaluated for antibacterial activity, revealing bactericidal and antibiofilm properties for some compounds. Importantly, promising preliminary absorption, distribution, metabolism, and excretion (ADME) properties in vitro were found and no cytotoxicity was detected for some representative compounds when tested in Galleria mellonella larvae.

Immunomodulation and Protective Effects of Cordyceps militaris Extract Against Candida albicans Infection in Galleria mellonella Larvae.

Cordyceps militaris-derived formulations are currently used for multiple purposes because of their medical properties, especially immune system modulation. This study analyzes the inhibitory effects of C. militaris aqueous extract on Candida albicans infections and the immune response in larvae of the greater wax moth Galleria mellonella (Lepidoptera: Pyralidae). Larvae exhibited melanization within 1 h of being infected with C. albicans inoculum at a concentration of 106 cells/larvae, and died within 24 h from a lethal dose. Aqueous extract of C. militaris proved to be nontoxic at concentrations of 0.25 and 0.125 mg/larvae, and had the greatest ability to prolong the survival of larvae infected with a sublethal dose of C. albicans at a concentration of 105 cells/larvae. Moreover, the number of hemocytes in the hemolymph of G. mellonella increased after infection with C. albicans and treatment with the aqueous extract of C. militaris at 1, 24, and 48 h by 1.21 × 107, 1.23 × 107, and 1.4 × 107 cells/100 µL, respectively. The highest number of hemocytes was recorded after treatment of infected G. mellonella with the extract for 48 h. Transcriptional upregulation of the immune system was observed in certain antimicrobial peptides (AMPs), showing that the relative expression of galiomicin, gallerimycin, and lysozyme genes were upregulated as early as 1 h after infection. Therefore, we conclude that C. militaris aqueous extract can modulate the immune system of G. mellonella and protect against infection from C. albicans.

(E, E)-farnesol and myristic acid-loaded lipid nanoparticles overcome colistin resistance in Acinetobacter baumannii

The rise of colistin-resistant Acinetobacter baumannii has severely limited treatment options for infections caused by this pathogen. While terpene alcohols and fatty acids have shown potential to enhance colistin’s efficacy, but their high lipophilicity limits their clinical application. To address this, we developed water-dispersible lipid nanoparticles (LNPs) in two sizes (40 nm and 130 nm), loaded with these compounds to act as colistin adjuvants. Among eleven LNP formulations, six significantly reduced colistin’s minimum inhibitory concentration (MIC) by 16- to 64-fold. The most effective, featuring (E,E)-farnesol and myristic acid, were further examined for bactericidal activity, membrane disruption, cytotoxicity, and in vivo efficacy in Galleria mellonella larvae. Time-kill studies demonstrated that at an adjuvant concentration of 60 mg/L, these LNPs eradicated bacteria when combined with 4 mg/L free colistin for resistant isolates (MIC = 128 mg/L) and 0.06 mg/L for susceptible isolates (MIC = 0.5 mg/L), without regrowth. Myristic acid-loaded LNPs combined with free colistin at 1/8 MIC resulted in a 4.2-fold higher mortality rate than the combination with (E,E)-farnesol-loaded LNPs in resistant strains. This result was correlated with a 45-fold faster increase in inner membrane permeability, measured by propidium iodide (PI) uptake, in the presence of myristic acid-loaded LNPs compared with a 13-fold faster increase with (E,E)-farnesol-loaded LNPs. DiSC3(5) assays revealed that LNPs alone depolarised the bacterial inner membrane, with enhanced effects when combined with colistin at 1/8 MIC, a result not observed with colistin alone at this concentration. As with PI uptake, this inner membrane depolarising effect was more pronounced with myristic acid-loaded LNPs than with (E,E)-farnesol-loaded LNPs in resistant strains, suggesting that the colistin adjuvant effect of these lipophilic compounds is due to their ability to help colistin destabilise the bacterial inner membrane. Cytotoxicity assays demonstrated no adverse effects on bone marrow macrophages after 6 h of exposure, although some toxicity was observed after 24 h. No mortality was observed in Galleria mellonella larvae over 7 days following three consecutive days of treatment with colistin and LNPs. Notably, the combination of (E,E)-farnesol-loaded LNPs and colistin significantly improved the survival of Galleria infected with A.baumannii. These results suggest that lipophilic-adjuvant-loaded LNPs may offer a promising strategy to enhance colistin efficacy and combat antibiotic-resistant A. baumannii infections.

Antimicrobial and antibiofilm activity of human recombinant H1 histones against bacterial infections.

Histones possess significant antimicrobial potential, yet their activity against biofilms remains underexplored. Moreover, concerns regarding adverse effects limit their clinical implementation. We investigated the antibacterial efficacy of human recombinant histone H1 subtypes against Pseudomonas aeruginosa PAO1, both planktonic and in biofilms. After the in vitro tests, toxicity and efficacy were assessed in a P. aeruginosa PAO1 infection model using Galleria mellonella larvae. Histones were also evaluated in combination with ciprofloxacin (Cpx) and gentamicin (Gm). Our results demonstrate antimicrobial activity of all three histones against P. aeruginosa PAO1, with H1.0 and H1.4 showing efficacy at lower concentrations. The bactericidal effect was associated with a mechanism of membrane disruption. In vitro studies using static and dynamic models showed that H1.4 had antibiofilm potential by reducing cell biomass. Neither H1.0 nor H1.4 showed toxicity in G. mellonella larvae, and both increased larvae survival when infected with P. aeruginosa PAO1. Although in vitro synergism was observed between ciprofloxacin and H1.0, no improvement over the antibiotic alone was noted in vivo. Differences in antibacterial and antibiofilm activity were attributed to sequence and structural variations among histone subtypes. Moreover, the efficacy of H1.0 and H1.4 was influenced by the presence and strength of the extracellular matrix. These findings suggest histones hold promise for combating acute and chronic infections caused by pathogens such as P. aeruginosa.IMPORTANCEThe constant increase of multidrug-resistant bacteria is a critical global concern. The inefficacy of current therapies to treat bacterial infections is attributed to multiple mechanisms of resistance, including the capacity to form biofilms. Therefore, the identification of novel and safe therapeutic strategies is imperative. This study confirms the antimicrobial potential of three histone H1 subtypes against both Gram-negative and Gram-positive bacteria. Furthermore, histones H1.0 and H1.4 demonstrated in vivo efficacy without associated toxicity in an acute infection model of Pseudomonas aeruginosa PAO1 in Galleria mellonella larvae. The bactericidal effect of these proteins also resulted in biomass reduction of P. aeruginosa PAO1 biofilms. Given the clinical significance of this opportunistic pathogen, our research provides a comprehensive initial evaluation of the efficacy, toxicity, and mechanism of action of a potential new therapeutic approach against acute and chronic bacterial infections.

Expression and characterization of pantothenate energy-coupling factor transporters as an anti-infective drug target.

This study investigates the potential of energy-coupling factor (ECF) transporters as promising anti-infective targets to combat antimicrobial resistance (AMR). ECF transporters, a subclass of ATP-binding cassette (ABC) transporters, facilitate the uptake of B-vitamins across bacterial membranes by utilizing ATP as an energy source. Vitamins are essential cofactors for bacterial metabolism and growth, and they can either be synthesized de novo or absorbed from the environment. These transporters are considered promising drug targets, underscoring the need for further research to harness their medicinal potential and develop selective inhibitors that block vitamin uptake in bacteria. Herein, we focused on the ECF transporter for pantothenate (vitamin B5) from Streptococcus pneumoniae and the ECF transporter for folate (vitamin B9) from Lactobacillus delbrueckii as a reference protein. We also included the energizing module for pantothenate along with both full transporter complexes. Initially, we transformed and purified the transporters, followed by an assessment of their thermal stability under various buffer composition, pH, and salt concentrations. Additionally, we monitored the melting temperature over six days to confirm their stability for further assays. We then measured the binding affinities of six ECF inhibitors using surface plasmon resonance (SPR) and evaluated their inhibitory effects through in vitro assays, including bacterial growth assay, whole-cell uptake, and transport-activity assays. After determining cytotoxicity in two human cell lines, we established an in vivo infection model using Galleria mellonella larvae to further validate our findings.

Galleria mellonella as an Antimicrobial Screening Model.

To combat the rising global issue of antibiotic resistance, the accelerated development of novel antibiotics is essential. Current preclinical antimicrobial development yields a significant number of leads that prove unsuitable either prior to or during clinical trials. To increase the efficiency of preclinical development, relevant, standardized, accessible, and cost-effective models must be developed. Galleria mellonella (greater wax moth) larvae are widely used as an infection model to assess microbial virulence, conduct drug toxicity testing, and serve as a preliminary means of evaluating the in vivo efficacy of novel antimicrobial compounds. These infection models have greater biological relevance than many in vitro screens of comparable throughput and decrease reliance on mammalian models when used as a pre-screen for antimicrobial testing. This protocol describes a standardized methodology for the optimization of G. mellonella infection models, which can be applied to bacterial species and antimicrobial therapeutics of choice. Using the WHO priority pathogen Pseudomonas aeruginosa as an exemplar, we outline steps that can be undertaken to develop a reproducible model of infection and therapeutic testing. This includes recommendations on experimental setup, sample preparation, and infection and treatment protocols. Integration of this model within preclinical antimicrobial development pipelines would decrease reliance on mammalian models, reduce the number of ineffective compounds reaching clinical trials, and ultimately increase the efficiency of preclinical antimicrobial development.

Multifaceted roles of NADPH oxidases in the growth and pathogenicity of Beauveria bassiana

ABSTRACT Reactive oxygen species (ROS), synthesized by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) complex, are vital molecules in biological cells, influencing various physiological processes such as fungal growth, development, and virulence. Beauveria bassiana, an entomopathogenic fungus, is a promising biopesticide for agricultural, forestry, and urban pest control. This study focuses on the characterization of NADPH oxidases (Noxs) in B. bassiana. Gene expression profiles of Noxs in B. bassiana (BbNoxs) were analysed using RT-qPCR. Knockout strains of single BbNoxA, BbNoxB, BbNoxR, and double BbNoxA and BbNoxB were constructed via homologous recombination, and their phenotypic characteristics were examined. Fungal virulence was evaluated using Galleria mellonella larvae, and infection structures formation and penetration ability were assessed on cicada wings. ROS production and actin assembly during fungal growth and infection were detected using staining and marker methods. Expression analysis revealed significant upregulation of BbNoxs during fungal growth and infection. Compared to the wild-type strain, single knockouts (ΔBbNoxA/B/R) and double knockout (ΔBbNoxAB) of BbNoxs exhibited reduced conidial yields, accelerated conidial germination rates. Deletion of BbNoxB or BbNoxR decreased fungal virulence compared to the WT strain in topical inoculation experiments. Additionally, loss of BbNoxB or BbNoxR impaired infection structures formation, penetration ability, ROS production, and actin aggregation during fungal infection. BbNoxs are crucial for fungal growth, development, and virulence in B. bassiana, playing essential roles in infection structures formation, penetration, ROS production, and actin assembly. Understanding their functions provides insights into B. bassiana’s pathogenic mechanisms.

Phthalocyanine derivative attenuates TNF-α production in macrophage culture and prevents alveolar bone loss in experimental periodontitis.

This study investigated the activity and mechanism of action of the iron tetracarboxyphthalocyanine (FeTcPc) on tumor necrosis factor alpha (TNF-α) production and its impact on experimental periodontitis. RAW 264.7 macrophages were treated with FeTcPc, activated with lipopolysaccharide (LPS) at 10 ng/mL, and the TNF-α levels were measured, as well as the nuclear factor kappa B (NF-κB) activation. Subsequently, a mouth gel containing 1% FeTcPc was topically administered to the gingival tissue of mice with periodontitis-induced ligatures. Bone loss and the gene expression of Tnfα, p65 (NF-κB), and receptor-activating nuclear factor kappa B ligand (Rankl) were quantified in gingival tissue. Finally, the systemic toxicity of FeTcPc was estimated in Galleria mellonella larvae. In an activated RAW 264.7 macrophage culture, 100 μM FeTcPc reduced TNF-α release and NF-κB activation. Regarding experimental periodontitis, topical application of mouth gel containing 1% FeTcPc blocked alveolar bone loss. Additionally, 1% FeTcPc reduced the expression of Tnfα, p65 (NF-κB), and Rankl in gingival tissue. Finally, administration FeTcPc at doses ranging from 1 to 1000 mg/kg did not cause acute systemic toxicity in G. mellonella. Overall, we demonstrated the potential of mouth gel containing FeTcPc as a therapeutic strategy for managing osteolytic inflammatory disorders, such as periodontitis.

Toxicity and Physiological Effect of Lemongrass Essential Oil Nano-capsules on the Greater Wax Moth Larvae Galleria mellonella L. (Lepidoptera: Pyralidae)

Toxicity and Physiological Effect of Lemongrass Essential Oil Nano-capsules on the Greater Wax Moth Larvae Galleria mellonella L. (Lepidoptera: Pyralidae)

Structural characterization and bioactivity profiling of the fungal peptaibiotic tolypin reveal protective effects against influenza viruses.

In a bioprospection for new antivirals, we tested nonribosomally biosynthesized polypeptide antibiotics in MDCK II cells for their actions on influenza A and B viruses (IAV/IBV). Only tolypin, a mixture of closely related 16-residue peptaibiotics from the fungus Tolypocladium inflatum IE 1897, showed promising activity. It was selected for further investigation and structural characterization byultrahigh performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HR-MS/MS) and ultrahigh performance liquid chromatography coupled to in-source collision-induced dissociation tandem mass spectrometry (UHPLC-isCID-HR-MS/MS), revealing 12 partially co-eluting individual peptides that were fully sequenced. Since tolypin-related efrapeptins are potent inhibitors of F1/Fo-ATPase, we screened tolypin for its toxicity against MDCK II cells and larvae of the greater wax moth Galleria mellonella. We found that a nontoxic concentration of tolypin (1 µg/mL) reduced the titer of two IBV strains by 4-5 log values, and that of an H3N2 strain by 1-2 log values, but the H1N1pdm strain was not affected. The higher concentrations of tolypin were cytostatic to MDCK II cells, shifted their metabolism from oxidative phosphorylation to glycolysis, and induced paralysis in G. mellonella, supporting the inhibition of F1/Fo-ATPase as the mode of action. Our results lay the foundations for future work to investigate the interplay between viral replication and cellular energy metabolism, as well as the development of drugs that target host factors.

Selection of a virulent Beauveria bassiana propagule, resistant to thermal stress and UV-ab radiation

Beauveria bassiana produces blastospores as propagules in liquid medium and conidia on solid substrate; its virulence was evaluated on Galleria mellonella larvae. The conidia cultured on ground rice that caused a 97% mortality were subjected to thermal stress and of UV-ab radiation, having as response their viability, measured as germination. After 15 h, conidia germinated 90% when subjected at 50°C for 80 min; and after 9 h, conidia germinated 87% when were subjected at 15000 mW/m2 radiation for 240 min. These results allow selecting the conidia as the propagules to be used in the formulation of a bioinsecticide product, as well as estimating their potential when applied in field, without additives to protect them.

Changes in Ergosterol Biosynthesis Alter the Response to Cycloheximide, 4-Nitroquinoline-N-Oxide, Weak Organic Acids, and Virulence in Candida glabrata.

The ERG6 gene encodes the sterol C24-methyltransferase converting zymosterol to fecosterol in the ergosterol biosynthetic pathway. Here, we extend the results of functional analysis of the CgERG6 gene, which was previously shown to modulate drug susceptibility in Candida glabrata mutant cells, by demonstrating that its deletion leads to increased susceptibility to cycloheximide, 4-nitroquinoline-N-oxide and weak organic acids, and such effects are associated with attenuated virulence. Together with abrogated efflux of drug substrates by CgCdr1p and CgPdr12p, the Cgerg6Δ mutation leads to reduced cell surface hydrophobicity and decreased virulence of the mutant cells of C. glabrata. The absence of CgErg6p impacts the lipid organization and function of the plasma membrane, resulting in non-specific permeability and abrogation of normal function of membrane-bound proteins accompanied by decreased virulence in Cgerg6Δ cells. Galleria mellonella larvae were used as a non-vertebrate animal host model to determine differences in the virulence potential of C. glabrata strains (parental strain and the Cgerg6Δ deletion mutant). We found that Cgerg6Δ mutant strain attenuated in virulence caused 25-30% survival of larvae compared with parental strain.

Effects of AI-2 quorum sensing related luxS gene on Streptococcus suis formatting monosaccharide metabolism-dependent biofilm.

Biofilm is the primary cause of persistent infections caused by Streptococcus suis (S. suis). Metabolism and AI-2 quorum sensing are intricately linked to S. suis biofilm formation. Although the role of the AI-2 quorum sensing luxS gene in S. suis biofilm has been reported, its specific regulatory mechanism remains unclear. This study explored the differences in biofilm formation and monosaccharide metabolism among the wild type (WT), luxS mutant (ΔluxS) and complement strain (CΔluxS), and Galleria mellonella larvae were used to access the effect of luxS gene deletion on the virulence of S. suis in different monosaccharide medias. The results indicated that deletion of the luxS gene further compromised the monosaccharide metabolism of S. suis, impacting its growth in media with fructose, galactose, rhamnose, and mannose as the sole carbon sources. However, no significant impact was observed in media with glucose and N-acetylglucosamine. This deletion also weakened EPS synthesis, thereby diminishing the biofilm formation capacity of S. suis. Additionally, the downregulation of adhesion gene expression due to luxS gene deletion was found to be independent of the monosaccharide medias of S. suis.

A novel fungal sensor (Ngs1) of N-acetylglucosamine (GlcNAc) mediates the fungal response to GlcNAc in the interaction between entomopathogenic Beauveria bassiana and insect host

As N-acetylglucosamine (GlcNAc) ubiquitously exists in both insect cuticle and fungal cell walls, the GlcNAc sensor (Ngs1) potentially plays important roles in the interactions between entomopathogenic fungi and their insect hosts. However, the roles of the Ngs1 derived from the entomopathogens in response to the host’s cuticle remain completely unexplored. In this study, a putative Ngs1 homolog was identified in the entomopathogenic fungus Beauveria bassiana. Deletion of Ngs1 significantly reduced virulence towards Galleria mellonella larvae either through cuticle infection (by 23%) or by bypassing the cuticle (by 44%). To investigate the role of Ngs1 in fungal virulence, an analysis of the transcriptome induced by Locusta migratoria exoskeleton was conducted, highlighting the regulatory mechanism of Ngs1 in carbohydrate metabolic process, particularly chitin metabolism and GlcNAc metabolism. Consistent with the transcriptomic data, Ngs1-deletion mutants showed reduced activities of both secreted chitinase (17% reduction) and Pr1 protease (35% reduction). Loss of Ngs1 down-regulated the transcript levels of GlcNAc-catabolism genes, resulting in a 17% decrease in fungal growth on GlcNAc-supported media. Furthermore, Ngs1 deficiency attenuated the fungal response to GlcNAc, leading to the alteration of fungal resistance to diverse stress cues. All of these changes contribute to the reduction in virulence in Ngs1-deficient B. bassiana. These findings support that Ngs1 plays a critical role in responding to insect-derived GlcNAc, affecting the production of cuticle-degrading enzymes to penetrate insect epidermis, GlcNAc-induced changes of stress resistance, and contribute to the fungal virulence against insects.

Evaluation of Klebsiella pneumoniae pathogenicity through holistic gene content analysis.

Klebsiella pneumoniae is a Gram-negative bacterium that causes both community- and healthcare-associated infections. Although various virulence factors and highly pathogenic phenotypes have been reported, the pathogenicity of K. pneumoniae is still not fully understood. In this study, we utilized whole-genome sequencing data of 168 clinical K. pneumoniae strains to assess pathogenicity. This work was based on the concept that the genetic composition of individual genomes (referred to as holistic gene content) of the strains may contribute to their pathogenicity. Holistic gene content analysis revealed two distinct groups of K. pneumoniae strains ('major group' and 'minor group'). The minor group included strains with known highly pathogenic clones (ST23, ST375, ST65 and ST86). The minor group had higher rates of capsular genotype K1 and presence of nine specific virulence genes (rmpA, iucA, iutA, irp2, fyuA, ybtS, iroN, allS and clbA) compared to the major group. Pathogenicity was assessed using Galleria mellonella larvae. Infection experiments revealed lower survival rates of larvae infected with strains from the minor group, indicating higher virulence. In addition, the minor group had a higher string test positivity rate than the major group. Holistic gene content analysis predicted possession of virulence genes, string test positivity and pathogenicity as observed in the G. mellonella infection model. Moreover, the findings suggested the presence of as yet unrecognized genomic elements that are either involved in the acquisition of virulence genes or associated with pathogenicity.

Effect of Co-Diet Supplementation on Biodegradation of Polyethylene by Galleria mellonella L. (Lepidoptera: Pyralidae).

Pollution coming from plastic polymers, particularly polyethylene (PE), poses a serious threat to both humans and animals. The biodegradation of plastics facilitated by insects is a crucial and eco-friendly approach that can be employed to combat this global concern. Recently, the larvae of the greater wax moth Galleria mellonella (L.) have been recognized as avid 'plastivores'. The current study was aimed at evaluating the feeding efficiency of G. mellonella larvae on PEs of various densities with a co-diet supplementation of wheat germ + honey and beeswax. The results reveal that maximum PE consumption (9.98 ± 1.25 mg) was recorded in the case of 1.0 mm thick PE after a 24 h interval; however, the same scenario also achieved the greatest reduction in larval weight (27.79 ± 2.02 mg). A significant reduction in PE mass (5.87 ± 1.44 mg) was also observed in 1.0 mm PE when fed beeswax; however, the larvae experienced minimal weight loss (9.59 ± 3.81 mg). The larvae exhibited a higher PE consumption in 1.0 mm PE, indicating that the lower the density of PE, the greater the consumed area. Moreover, the biodegradation levels were notably higher within the 24 h interval. In conclusion, these findings suggest that the density of PEs and the supplementation of the co-diet have an impact on PE biodegradation. Additionally, the utilization of G. mellonella for the biodegradation of PE proves effective when combined with beeswax, resulting in minimal weight loss of the larvae. Our findings offer initial insights into how Galleria mellonella larvae biodegrade polyethylene (PE) of four different densities, along with co-diet supplementation. This approach helps us evaluate how varying densities affect degradation rates and provides a better understanding of the larvae's capabilities. Additionally, our observations at three specific time intervals (24, 48, and 72 h) allow us to identify the time required for achieving degradation rates. Through examining these time points, our method offers valuable insights into the initial phases of plastic consumption and biodegradation.

Exploring the toxicity profile of coriander (C. sativum L.) essential oil: implications for translational toxicological research

The plant species C. sativum L. is a staple in cuisine and holds significant ethnopharmacological value. Its essential oil (EO) is of particular interest, yet its toxicity profile remains a subject of inquiry. This study aimed to elucidate the chemical constituents of C. sativum L. EO and evaluate its toxicity through various parameters, including cytotoxicity assays on HaCaT keratinocytes, in vivo toxicity tests on Galleria mellonella larvae, in vivo genotoxicity assessments on mice and cytotoxicity assays on human erythrocytes. Notably, major constituents such as 2-decen-1-ol, dec-(2E)-enal, and 1,6-octadien-3-ol were found to remain predominant. The IC50 value for the essential oil on the keratinocyte cell line was determined to be 60.13 ± 2.02 µg/mL. However, in vivo toxicity tests with G. mellonella larvae demonstrated safety at doses below 4.5 g/kg. Additionally, genotoxicity assessment revealed that a single dose of 20 mg/mL (5 mg/kg) did not induce a significant increase in micronuclei formation. EO concentrations above 250 µg/mL led to significant changes in human erythrocytes cell viability (p < 0.0001), resulting in over 60% hemolysis. These findings collectively suggest that the essential oil of C. sativum L. exhibits a suitable toxicity profile for conducting preclinical studies in vertebrate animal models.

Ecological aspects of three strains of entomopathogenic nematodes from the department of Lambayeque-Peru

BackgroundEntomopathogenic nematodes (EPN) are used as a biological control agent for different insect pests in agriculture. The genera Heterorhabditis and Steinernema are the most used commercially. For an EPN species to be used as a biological controller, it is necessary to know its ecological aspects, including reproductive potential, movement capacity, and mean lethal concentration (LC50). These aspects were evaluated in three EPN strains isolated in Galleria mellonella larvae collected in the Lambayeque-Peru region, to determine if they are promising as biological controllers. The strains of EPN studied are Heterorhabditis sp. (PC9 strain), H. bacteriophora Poinar (PM10 strain), and Steinernema diaprepesi Nguyen y Duncan (SV19 strain).ResultsHeterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) had high production of infective juveniles (IJs): 217.750 and 186.800, respectively, while S. diaprepesi (SV19 strain) only reached 84.150 IJs. The movement capacity of Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) reached a depth of 15 cm to parasitize G. mellonella larvae, while S. diaprepesi (SV19 strain) only reached 10 cm. In decreasing order, the LC50 value of S. diaprepesi (SV19 strain), Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) were: 24.03, 13.74, and 8.19 IJs/ml, respectively.ConclusionsHeterorhabditis sp. PC9 and H. bacteriophora PM10 are promising a biological control agent because they present great production of IJs, great displacement capacity, and high pathogenicity against G. mellonella. Additionally, both strains present a mixed search strategy or seeker-hunter (seeker-browser).

Transcriptome analysis and functional study of phospholipase A2 in Galleria mellonella larvae lipid metabolism in response to envenomation by an ectoparasitoid, Iseropus kuwanae.

There is abundant evidence that parasitoids manipulate their hosts by envenomation to support the development and survival of their progeny before oviposition. However, the specific mechanism underlying host nutritional manipulation remains largely unclear. To gain a more comprehensive insight into the effects induced by the gregarious ectoparasitoid Iseropus kuwanae (Hymenoptera: Ichneumonidae) on the greater wax moth Galleria mellonella (Lepidoptera: Pyralidae) larvae, we sequenced the transcriptome of both non-envenomed and envenomed G. mellonella larvae, specifically targeting genes related to lipid metabolism. The present study revealed that 202 differentially expressed genes (DEGs) were identified and 9 DEGs were involved in lipid metabolism. The expression levels of these 9 DEGs relied on envenomation and the duration post-envenomation. Further, envenomation by I. kuwanae induced an increase in triglyceride (TG) level in the hemolymph of G. mellonella larvae. Furthermore, silencing GmPLA2 in G. mellonella larvae 24h post-envenomation significantly decreased the content of 4 unsaturated fatty acids and TG levels in the hemolymph. The content of linoleic acid and α-linoleic acid were significantly decreased and the content of oleic acid was significantly increased by exogenous supplement of arachidonic acid. Meanwhile, the reduction in host lipid levels impairs the growth and development of wasp offspring. The present study provides valuable knowledge about the molecular mechanism of the nutritional interaction between parasitoids and their hosts and sheds light on the coevolution between parasitoids and host insects.