Moth Larvae Research Articles

Heterologous expression of distinct insecticidal genes in potato cultivars encodes resistance against potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae)

AbstractThe potato tuber moth, Phthorimaea operculella (Zeller), is a notorious insect pest of potato incurring substantial yield losses in the field as well as in storage. Chemical control is difficult to exercise due to the latent feeding of the caterpillars and their ability to develop resistance against insecticides. One of the essential components of efficient insect-resistant management is using two or more different insecticidal genes in transgenic crops to effectively avoid and delay the resistance development in insect pests. Two constructs, namely DS-1 (cry3A + SN-19 genes) and DS-2 (OCII + SN-19 genes) in pCAMBIA1301 binary vector, were developed and were transformed in potato cultivars (Agria and Lady Olympia) via Agrobacterium-mediated transformation. The molecular analysis confirmed gene integration and expression of the introduced genes in transgenic plants. The insecticidal effects of incorporated genes in transgenic plants were assessed against 1st, 2nd, 3rd, and 4th instar potato tuber moth (PTM) larvae. The transgenic plants endured significantly high mortalities (100%) of larval stages of PTM within 72 h. Our results show that these transgenic potato plants have the potential to control populations of PTM and are also useful tools in managing PTM that would ultimately reduce the dependency on conventional chemical pesticides with potentially less or minimal hazards. These lines can also serve as an excellent source of germplasm for potato breeding program.

Antibiotics suppress the expression of antimicrobial peptides and increase sensitivity of Cydia pomonella to granulosis virus

Cydia pomonella granulovirus (CpGV) is a highly specific and environmentally friendly pathogenic virus successfully used as a biological insecticide against codling moth larvae. Continuous application of CpGV has led to high levels of resistance in codling moth, Cydia pomonella (C. pomonella). Nevertheless, the specific molecular mechanisms underlying the development of resistance in codling moths to CpGV have been rarely investigated. This study explored the potential antiviral immune roles of codling moth antimicrobial peptides (AMPs) against CpGV. A total of 11 AMP genes classified in cecropin, defensin, gloverin, and attacin subfamilies, were identified in the codling moth genome. The cecropin and gloverin subfamilies were found to be the ancestral genes of the AMP gene family. The expression of two AMP genes (CmGlo1 and CmAtt1) significantly increased following CpGV challenge, and CmGlo1 and CmAtt1 gene silencing resulted in a significant increase in CpGV replication in codling moth larvae. The hemolymph and fat body serve as major viral immune functional tissues in codling moth larvae. Moreover, zhongshengmycin significantly reduced the diversity and abundance of codling moth larvae gut microbiota, thereby suppressing the expression of CmAtt1 AMP gene. We also found that the combination of the virus with zhongshengmycin would enhance the insecticidal effects of CpGV. This study provides the first explanation of the molecular mechanisms driving CpGV immune function development in codling moths, approached from the perspective of the codling moth itself. Additionally, we introduced an alternative approach to combat codling moth in the field by combining antibiotics with biopesticides to amplify the insecticidal effects of the latter.

The role of social media in public health awareness during times of war in Sudan: snakebites and scorpion stings

BackgroundSnakebite envenomation (SBE) and scorpion sting envenomation (SSE) are significant neglected tropical diseases that primarily affect impoverished communities in rural areas of developing nations. A lack of understanding about snake and scorpion species and their distribution exacerbates the disabilities and fatalities caused by SBE and SSE. In Sudan, particularly in regions affected by ongoing conflicts where healthcare resources are scarce, social media platforms offer a cost-effective approach to addressing public health challenges. Our aim in this study is to highlight the benefits of using social media for data collection and health promotion in such environments.MethodsWe present a cost-effective communication and data collection strategy implemented at the Toxic Organisms Research Centre (TORC) of the University of Khartoum, focusing on a Facebook group, “Scorpions and Snakes of Sudan”, as our primary social media platform. Additionally, we discuss the lessons learned and the initial impact of this strategy on enhancing population health literacy.ResultsThe group community is composed of ~ 5000 members from 14 countries. During the period from January 2023 to January 2024, we received 417 enquiries about snakes and scorpions belonging to 11 families and composed of 55 species. In addition, 53 other enquiries covered a range of organisms and their tracks (e.g., spiders, skinks, chameleons, foxes, sun spiders, centipedes, lizards, moth larvae, and insect tracks). The first photographic evidence of Malpolon monspessulanus in Sudan was via the group activities. The rare species Telescopus gezirae, the Blue Nile cat snake, is also documented via the group member’s queries. Recognizing the evolving nature of social media use in public health, we also address the current limitations and evidence gaps that need to be addressed to effectively translate best practices into policy.ConclusionIn conclusion, utilizing Facebook as an institutional platform to share scientific information in simple Arabic language underscores the proactive roles that citizens, scientists, and public health stakeholders can play in leveraging social media for eHealth, eAwareness, and public health initiatives. This approach highlights the potential for collaborative efforts, particularly during crises, to maximize the benefits of social media in advancing public health.

Minimizing IP issues associated with gene constructs encoding the Bt toxin - a case study

BackgroundAs part of a publicly funded initiative to develop genetically engineered Brassicas (cabbage, cauliflower, and canola) expressing Bacillus thuringiensis Crystal (Cry)-encoded insecticidal (Bt) toxin for Indian and Australian farmers, we designed several constructs that drive high-level expression of modified Cry1B and Cry1C genes (referred to as Cry1BM and Cry1CM; with M indicating modified). The two main motivations for modifying the DNA sequences of these genes were to minimise any licensing cost associated with the commercial cultivation of transgenic crop plants expressing CryM genes, and to remove or alter sequences that might adversely affect their activity in plants.ResultsTo assess the insecticidal efficacy of the Cry1BM/Cry1CM genes, constructs were introduced into the model Brassica Arabidopsis thaliana in which Cry1BM/Cry1CM expression was directed from either single (S4/S7) or double (S4S4/S7S7) subterranean clover stunt virus (SCSV) promoters. The resulting transgenic plants displayed a high-level of Cry1BM/Cry1CM expression. Protein accumulation for Cry1CM ranged from 5.18 to 176.88 µg Cry1CM/g dry weight of leaves. Contrary to previous work on stunt promoters, we found no correlation between the use of either single or double stunt promoters and the expression levels of Cry1BM/Cry1CM genes, with a similar range of Cry1CM transcript abundance and protein content observed from both constructs. First instar Diamondback moth (Plutella xylostella) larvae fed on transgenic Arabidopsis leaves expressing the Cry1BM/Cry1CM genes showed 100% mortality, with a mean leaf damage score on a scale of zero to five of 0.125 for transgenic leaves and 4.2 for wild-type leaves.ConclusionsOur work indicates that the modified Cry1 genes are suitable for the development of insect resistant GM crops. Except for the PAT gene in the USA, our assessment of the intellectual property landscape of components presents within the constructs described here suggest that they can be used without the need for further licensing. This has the capacity to significantly reduce the cost of developing and using these Cry1M genes in GM crop plants in the future.

Harposporium incensis sp. nov. a South American cordycipitoid species exhibiting inter-phylum host-jumping and having potential as a biological control agent for pest management

ABSTRACT Macro- and microscopic morphological studies and multilocus phylogenetic analysis were made on larval specimens of a ghost moth collected from a pigeon pea plantation in Huánuco, Peru. DNA sequences from the cadaver and the fungal isolates obtained represented a monophyletic clade based on the phylogeny. All morphological characters and molecular data showed that the pathogenic fungus infecting the ghost moth larvae was an unknown cordycipitoid species, herein described as, Harposporium incensis sp. nov. based on morphological features and multilocus phylogenetic analysis on the cadaver and fungus isolated from the same specimen. The far-related and ecologically different hosts of teleomorph and anamorph of this new species display a peculiar inter-phylum host jumping between the insect Trichophassus giganteus of the phylum Arthropoda and the nematode Caenorhabditis elegans of the phylum Nematoda and have biological control potential.

Winter moth populations are isolated on co‐occurring tree species with contrasting budburst‐phenology

Abstract Differences between neighbouring tree species in phenology could isolate populations of host plant generalists that depend on matching the phenology of their host. We studied the relationship between the budburst phenology of two co‐occurring tree species with early (hornbeams) and late (oaks) budburst and the egg hatching date of associated winter moths (Operophtera brumata) during two seasons (autumns starting in 2020 and 2021). A previous study in spring 2019 had found no winter moth larvae on the focal oaks, while we found them mainly on oaks with hornbeam neighbours in 2022. Congruently, adult winter moths were rarely encountered during the autumns of 2018 and 2019 and sparsely in 2020 and 2021, and then mainly near hornbeams. The vast majority of winter moths had early hatching eggs when both hornbeams and oaks were present, matching the hornbeams rather than the oaks. Where hornbeam was absent in the neighbourhood, the few winter moths had late hatching eggs. These results suggest that winter moth populations on hornbeam and oak are to some degree isolated from each other despite spatial proximity, so that recolonization of oaks by populations synchronized with budburst of hornbeam is slow. Therefore, trees would benefit from differing from their neighbours in budburst phenology with respect to herbivore damage.

The individual contributions of blaB, blaGOB and blaCME on MICs of β-lactams in Elizabethkingia anophelis.

The blaB, blaGOB and blaCME genes are thought to confer β-lactam resistance to Elizabethkingia anophelis, based on experiments conducted primarily on Escherichia coli. To determine the individual contributions of β-lactamase genes to increased MICs in E. anophelis and to assess their impact on the in vivo efficacy of carbapenem therapy. Scarless gene deletion of one or more β-lactamase gene(s) was performed in three clinical E. anophelis isolates. MICs were determined by broth microdilution. Hydrolytic activity and expressions of β-lactamase genes were measured by an enzymatic assay and quantitative RT-PCR, respectively. In vivo efficacy was determined using Galleria mellonella and murine thigh infection models. The presence of blaB resulted in >16-fold increases, while blaGOB caused 4-16-fold increases of carbapenem MICs. Hydrolysis of carbapenems was highest in lysates of blaB-positive strains, possibly due to the constitutionally higher expression of blaB. Imipenem was ineffective against blaB-positive isolates in vivo in terms of improvement of the survival of wax moth larvae and reduction of murine bacterial load. The deletion of blaB restored the efficacy of imipenem. The blaB gene was also responsible for a >4-fold increase of ampicillin/sulbactam and piperacillin/tazobactam MICs. The presence of blaCME, but not blaB or blaGOB, increased the MICs of ceftazidime and cefepime by 8-16- and 4-8-fold, respectively. The constitutionally and highly expressed blaB gene in E. anophelis was responsible for increased MICs of carbapenems and led to their poor in vivo efficacy. blaCME increased the MICs of ceftazidime and cefepime.

Biological activity of essential oils of Calocedrus decurrens and Cupressus arizonica on Lymantria dispar larvae and Phytophthora root pathogens

Composition of Calocedrus decurrens and Cupressus arizonica essential oils (CDEO and CAEO, respectively), their antifeedant activity on spongy moth (Lymantria dispar) larvae, as well as their antimicrobial activity on three Phytophthora species were investigated. In leaves of these two conifers from the Cupressaceae family, monoterpenes strongly dominated (90.5 and 85.0%, respectively), but their terpene profiles were different. The dominant compound of CDEO was δ-3-carene (49.5%), followed by myrcene (9.4%), terpinolene (8.6%) and α-pinene (7.0%). In CAEO, the most dominant compounds were limonene (23.3%) and α-pinene (20.5%), followed by umbellulone (12.0%) and terpinen-4-ol (9.5%). CDEO showed a strong antifeedant activity, while leaf discs treated with CAEO had phagostimulatory effect on spongy moth larvae. CAEO had no significant effect on relative consumption and larval growth rate, while CDEO reduced consumption and stimulated growth at the lowest EO concentration (0.05%). Both EOs significantly affected the growth of colonies of the Phytophthora species tested. At concentrations of 0.5% and 1%, a 100% inhibition was observed in almost all experimental groups, with the exception of P. plurivora on 0.5% CDEO. At a concentration of 0.1% inhibition rate varied from 15% in P. ×cambivora treated with CDEO to 90% in P. quercina treated with CAEO. These findings indicate that these two EOs could be used to control tree pests.

The effect of local habitat and spatial connectivity on urban seed predation.

During the last centuries, the area covered by urban landscapes is increasing all over the world. Urbanization can change local habitats and decrease connectivity among these habitats, with important consequences for species interactions. While several studies have found a major imprint of urbanization on plant-insect interactions, the effects of urbanization on seed predation remain largely unexplored. We investigated the relative impact of sunlight exposure, leaf litter, and spatial connectivity on predation by moth and weevil larvae on acorns of the pedunculate oak across an urban landscape during 2018 and 2020. We also examined whether infestations by moths and weevils were independent of each other. While seed predation varied strongly among trees, seed predation was not related to differences in sunlight exposure, leaf litter, or spatial connectivity. Seed predation by moths and weevils was negatively correlated at the level of individual acorns in 2018, but positively correlated at the acorn and the tree level in 2020. Our study sets the baseline expectation that urban seed predators are unaffected by differences in sunlight exposure, leaf litter, and spatial connectivity. Overall, our findings suggest that the impact of local and spatial factors on insects within an urban context may depend on the species guild. Understanding the impact of local and spatial factors on biodiversity, food web structure, and ecosystem functioning can provide valuable insights for urban planning and management strategies aimed at promoting urban insect diversity.

Transplanting human infant gut microbiome species into Galleria mellonella

ObjectiveStudy of the human infant gut microbiome requires the use of surrogate mammalian species such as mice. We sought to investigate the usefulness of the greater wax moth larva, Galleria mellonella, as an alternative.ResultsWe have analysed the native gut microbiome of Galleria and developed methods for clearing the native microbiome and introducing species from human infant faecal samples. We find that some species, e.g. enterococci, are more successful at recolonisation, but that others, e.g. Bifidobacterium, are less so. The work paves the way for using Galleria rather than mice in this and similar work.

The 3′ UTR of vigR is required for virulence in Staphylococcus aureus and has expanded through STAR sequence repeat insertions

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are alarmingly common, and treatment is confined to last-line antibiotics. Vancomycin is the treatment of choice for MRSA bacteremia, and treatment failure is often associated with vancomycin-intermediate S.aureus isolates. The regulatory 3' UTR of the vigR mRNA contributes to vancomycin tolerance and upregulates the autolysin IsaA. Using MS2-affinity purification coupled with RNA sequencing, we find that the vigR 3' UTR also regulates dapE, a succinyl-diaminopimelate desuccinylase required for lysine and peptidoglycan synthesis, suggesting a broader role in controlling cell wall metabolism and vancomycin tolerance. Deletion of the 3' UTR increased virulence, while the isaA mutant is completely attenuated in a wax moth larvae model. Sequence and structural analyses of vigR indicated that the 3' UTR has expanded through the acquisition of Staphylococcus aureus repeat insertions that contribute sequence for the isaA interaction seed and may functionalize the 3' UTR.

Glycerol metabolism impacts biofilm phenotypes and virulence in Pseudomonas aeruginosa via the Entner-Doudoroff pathway.

Pseudomonas aeruginosa is a ubiquitous bacterium and a notorious opportunistic pathogen that forms biofilm structures in response to many environmental cues. Biofilm formation includes attachment to surfaces and the production of the exopolysaccharide Pel, which is present in both the PAO1 and PA14 laboratory strains of P. aeruginosa. Biofilms help protect bacterial cells from host defenses and antibiotics and abet infection. The carbon source used by the cells also influences biofilm, but these effects have not been deeply studied. We show here that glycerol, which can be liberated from host surfactants during infection, encourages surface attachment and magnifies colony morphology differences. We find that glycerol kinase is important but not essential for glycerol utilization and relatively unimportant for biofilm behaviors. Among downstream enzymes predicted to take part in glycerol utilization, Edd stood out as being important for glycerol utilization and for enhanced biofilm phenotypes in the presence of glycerol. Thus, gluconeogenesis and catabolism of anabolically produced glucose appear to impact not only the utilization of glycerol but also glycerol-stimulated biofilm phenotypes. Finally, waxworm moth larvae and nematode infection models reveal that interruption of the Entner-Doudoroff pathway, but not abrogation of glycerol phosphorylation, unexpectedly increases P. aeruginosa lethality in both acute and chronic infections, even while stimulating a stronger immune response by Caenorhabditis elegans.IMPORTANCEPseudomonas aeruginosa, the ubiquitous environmental bacterium and human pathogen, forms multicellular communities known as biofilms in response to various stimuli. We find that glycerol, a common carbon source that bacteria can use for energy and biosynthesis, encourages biofilm behaviors such as surface attachment and colony wrinkling by P. aeruginosa. Glycerol can be derived from surfactants that are present in the human lungs, a common infection site. Glycerol-stimulated biofilm phenotypes do not depend on phosphorylation of glycerol but are surprisingly impacted by a glucose breakdown pathway, suggesting that it is glycerol utilization, and not its mere presence or cellular import, that stimulates biofilm phenotypes. Moreover, the same mutations that block glycerol-stimulated biofilm phenotypes also impact P. aeruginosa virulence in both acute and chronic animal models. Notably, a glucose-breakdown mutant (Δedd) counteracts biofilm phenotypes but shows enhanced virulence and stimulates a stronger immune response in Caenorhabditis elegans.

Identifying the Key Role of Plutella xylostella General Odorant Binding Protein 2 in Perceiving a Larval Attractant, (E,E)-2,6-Farnesol.

There is currently a lack of effective olfaction-based techniques to control diamondback moth (DBM) larvae. Identifying behaviorally active odorants for DBM larvae and exploring their recognition mechanisms can provide insights into olfaction-based larval control strategies. Through the two-choice assay, (E,E)-2,6-farnesol (farnesol) was identified as a compound exhibiting significant attractant activity toward DBM larvae, achieving an attraction index of 0.48 ± 0.13. PxylGOBP1 and PxylGOBP2, highly expressed in the antennae of DBM larvae, both showed high affinity toward farnesol. RNAi technology was used to knock down PxylGOBP1 and PxylGOBP2, revealing that the attraction of DBM larvae to farnesol nearly vanished following the knockdown of PxylGOBP2, indicating its critical role in recognizing farnesol. Further investigation into the PxylGOBP2-farnesol interaction revealed the importance of residues like Thr9, Trp37, and Phe118 in PxylGOBP2's binding to farnesol. This research is significant for unveiling the olfactory mechanisms of DBM larvae and developing larval behavior regulation techniques.

Caterpillar sonic defences: diversity of vocalisations in silk and hawk moth (Bombycoidea) larvae

ABSTRACT Several Bombycoidea caterpillars, renowned for their large size and diverse appearances, possess an intriguing hidden talent – the ability to ‘vocalise’. Vocalisation is a rare form of sound production in insects, whereby sounds emanate from the oral cavity by air being forced through the foregut. Here, we report on vocalisation in 10 Bombycoidea species that occur across three families. Sounds in all 10 species are evoked in response to simulated predator attacks. Species were identified as vocalisers based primarily on video evidence of mouthparts being open during sound production. Vocalisations, when considered collectively across all 10 species studied, sound like a train of ‘hisses’ (sound units) that occur following an attack. Each sound unit comprises a series of pulses (4–104 on average) and is broadband with high dominant frequency (24–49 kHz on average). Given that vocalising species occur in different families across this large superfamily, we asked whether related species shared similar sound features. We found considerable overlap between sound characteristics of different vocalising species, suggesting a shared mechanism overall. However, distinct differences were also noted between families, suggesting that vocalisation may have evolved multiple times within Bombycoidea. The evolutionary origins and specific functions of vocalisation in caterpillars are discussed.

Gum Moth Larvae

Gum Moth Larvae

Effect of the Neonicotinoid Insecticide Thiacloprid on Oxidative Stress, Genotoxic, and Immunotoxic Biomarkers in Greater Wax Moth, Galleria mellonella

The aim of this study was to investigate the effect of the neonicotinoid insecticide Thiacloprid on oxidative stress, genotoxic, and immunotoxic biomarkers in Galleria mellonella. The effects of neonicotinoid insecticide thiacloprid on antioxidant enzyme activities, malondialdehyde (MDA) levels, hemocyte number, micronucleus frequency of greater wax moth (Galleria mellonella) larvae at different doses (5, 10, 15, 20, 25, and 30 µg) and periods (24, 48, 72, and 96 hrs) were explored. Superoxide dismutase (SOD) activity increased significantly at 5, 10, and 15 µg thiacloprid doses compared to the control and negative control in all periods tested, while significantly decreased at 20, 25, and 30 µg doses. Catalase (CAT) activity showed significant increases at 5, 10 and 15 µg thiacloprid doses at 24 and 96h compared to the control and negative control. MDA concentrations showed significant increases in all periods compared to the control and negative control. At 24th, 48th, 72nd and 96th, total hemocyte count (THC) decreased significantly at all doses except 5 µg thiacloprid concentration. During all the tested periods, there was a significant increase in the number of micronuclei, particularly at high doses of thiacloprid (20, 25, and 30 µg) compared to both the control and negative control. Additionally, a positive correlation was observed between MDA and the number of micronuclei, while other markers showed a negative correlation with micronucleus (MN). These results suggest that high doses of thiacloprid induce significant increases in micronuclei formation and are positively correlated with MDA levels, indicating oxidative damage and genotoxicity caused by thiacloprid exposure in the tested organism. Overall, our findings suggest that the measured parameters can be considered reliable biomarkers to demonstrate oxidative damage from thiacloprid exposure.

Coexistence of virulent and multidrug-resistant plasmids in an uropathogenic Escherichia coli

ObjectivesThe emergence of pathogens co-harbouring multiple mobile resistance and virulence elements is of great concern in clinical settings. Herein, we report an O101: H10-ST167 Escherichia coli Hu106 strain isolated from the urinary tract of a female in China. MethodsAntibiotic susceptibility testing was used to present the antimicrobial resistance spectrum. Whole-genome sequencing (WGS) and bioinformatic analysis were used to clarify the virulent and resistance mechanisms. Furthermore, the virulence of this strain was tested by the Greater wax moth larvae and siderophore production experiment. ResultsThe strain E. coli Hu106 was resistant to almost all antimicrobials tested, and only susceptible to aztreonam, amikacin, and tigecycline. WGS analysis revealed that the strain Hu106 co-harboured blaNDM-9 and mcr-1 on p2-Hu106, belonging to IncHI2/IncHI2A (256,000 bp). The co-existence of both resistance genes, blaNDM-9 and mcr-1, on the plasmid p2-Hu106 was mainly acquired by transposition recombination of mobile antibiotic elements mediated by IS26 and/or IS1 on IncHI2/IncHI2A type plasmid. In addition, the virulence clusters aerobactin (iutA-iucABCD) and salmochelin (iroBCDEN) were identified on an IncFIB/IncFIC(IncFII) type plasmid p1-Hu106, flanked by small mobile elements such as IS1A, ISkpn28, and IS3, respectively. After performing genomic comparison of p1-Hu106 with the WGS in NCBI, we identified that the virulent plasmid p1-Hu106-like could spread in different clones of E. coli and Klebsiella pneumoniae, revealing its underlying dissemination mechanism between Enterobacterales. Furthermore, the strain caused a decreased survival rate of larvae and produced high siderophore units (62.33%), similar to hypervirulent K. pneumoniae NTUH-K2044. ConclusionsThe strains co-carrying the multidrug-resistant plasmid p2-Hu106 and virulent plasmid p1-Hu106 should be closely monitored to prevent its further spreading.

Functional and numerical response and mutual interference of Goniozus legneri (Hymenoptera: Bethylidae) on Cydia pomonella (Lepidoptera: Tortricidae): Its implications for biological control

AbstractThe functional and numerical response and the potential for mutual interference are key components in the selection of parasitoids for biological control. In this study, functional and numerical responses of Goniozus legneri to different densities of fifth instar Cydia pomonella larvae and mutual interference of this parasitoid were studied under laboratory conditions. Logistic regression was used to find the type of functional response and the result was type II. The attack rate, handling time, the parasitoid searching efficiency and the maximum host mortality rate were estimated by fitting the Holling model to the data. The numerical response of the parasitoid did not vary based on the availability of codling moth larvae. The negative value of the interference coefficient (−0.228) in the mutual interference analysis showed an inverse relationship between parasitoid density and per capita searching efficiency. This suggests that when the density of G. legneri and C. pomonella larvae is equivalent, the parasitoid proves to be more effective in pest control. The findings of this study contribute to increasing the knowledge of G. legneri and its potential as a biocontrol agent.

Structure-Activity Relationship Study to Develop Peptide Amphiphiles as Species-Specific Antimicrobials.

Antimicrobial peptide amphiphiles (PAs) are a promising class of molecules that can disrupt the bacterial membrane or act as drug nanocarriers. In this study, we prepared 33 PAs to establish supramolecular structure-activity relationships. We studied the morphology and activity of the nanostructures against different Gram-positive and Gram-negative bacterial strains (such as Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii). Next, we used principal component analysis (PCA) to determine the key contributors to activity. We found that for S. aureus, the zeta potential was the major contributor to the activity while Gram-negative bacteria were more influenced by the partition coefficient (LogP) with the following order P. aeruginosa>E. coli>A. baumannii. We also performed a study of the mechanism of action of selected PAs on the bacterial membrane assessing the membrane permeability and depolarization, changes in zeta potential and overall integrity. We studied the toxicity of the nanostructures against mammalian cells. Finally, we performed an in vivo study using the wax moth larvae to determine the therapeutic efficacy of the active PAs. This study shows cationic PA nanostructures can be an intriguing platform for the development of nanoantibacterials.

Biological and productive aspects of the black soldier fly Hermetia illucens (Diptera: Stratiomyidae) in meal moth rearing residues Ephestia kuehniella (Lepidoptera: Pyralidae)

AbstractThe inadequate disposal of organic waste generated in insect biofactories breeding biological agents may become a potential environmental problem. The use of Hermetia illucens (Diptera: Stratiomyidae) may play an important role in the circular economy of this process, transforming waste into high‐quality biomass. Therefore, this work aims to analyse the degradation of organic residues of Ephestia kuehniella (Lepidoptera: Pyralidae) production using the black soldier fly. Four types of waste from the moth breeding process were evaluated: residues of the meal diet when moth larvae were in the last instar; residues of the meal diet when completing the cycle; residues formed by webs in the pupation process mixed with residual exoskeleton, and residues of dead adults. These residues were tested in isolation and in mixtures of 50%, using as control a standard diet composed of chicken feed. Survival rate, development time, emerged adults, weight, size, residue reduction, and bioconversion were evaluated. The residue used in diets affected the total development time of H. illucens. The mean number of survivors differed from 87% to 74% for larvae that reached the pre‐pupal stage. The viability of pre‐pupae to adult stage ranged from 54% to 6% for residue treatments and 97% for the control. Differences in the growth and weight gain of larvae were significantly different. The rate of residue reduction from 54% to 80% and bioconversion into larval biomass were satisfactory. However, regarding adult emergence, the numbers show variations, indicating that certain residues are not suitable for the maintenance of fly breeding.