Bee health is influenced by multiple factors, including nutrition, immunity, and parasitic pressures. Since the spread of Varroa destructor, overwintering survival has significantly declined, making it one of the most serious threats to honey bee (Apis mellifera L.) populations worldwide. Natural acaricides, such as oxalic acid (OA), are widely employed for managing Varroa mites; however, their pharmacodynamics, particularly their impacts on honey bee physiology and immunity, remain insufficiently understood. We studied effects of oxalic acid on honey bee workers. The study compared three treatments: flumethrin, OA-glycerine strips (OA-G), and OA trickling (OA-T). Twelve colonies were divided into four groups, with samples collected at five time points (0, 24, 48, 72, and 192 h). Physiological changes were assessed through markers of oxidative stress, longevity, and immune parameters. Exposure to oxalic acid via glycerine strips induced a humoral immune response in adult bees. The antimicrobial activity of hemolymph and levels of antimicrobial peptides (abaecin, apidaecin, defensin, and hymenoptaecin) were elevated between 48 and 192 h after OA-G treatment compared to the control group. In contrast, these parameters were not influenced by OA-T or flumethrin treatment. These findings suggest that OA-G strips activate the honey bee's immune system, providing insights into broader implications of OA use in beekeeping. It is crucial to determine whether the activation of humoral immune systems has positive or negative effects, as well as to develop standardized and reliable treatment protocols that ensure both - health of colonies and their effectiveness in controlling Varroa mite infestations.
- Klíčová slova
- Beekeeping, Integrated Pest management, Oxalic acid, Pharmacodynamics, Treatment, Varroa,
- MeSH
- akaricidy * farmakologie MeSH
- antimikrobiální peptidy metabolismus MeSH
- hemolymfa účinky léků metabolismus MeSH
- kyselina oxalová * farmakologie MeSH
- oxidační stres účinky léků MeSH
- pyrethriny farmakologie MeSH
- Varroidae účinky léků MeSH
- včely imunologie účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- akaricidy * MeSH
- antimikrobiální peptidy MeSH
- flumethrin MeSH Prohlížeč
- kyselina oxalová * MeSH
- pyrethriny MeSH
Entomopathogenic nematodes (EPNs) are biological control agents that naturally kill insect pests, providing an eco-friendly alternative to chemical pesticides. Despite extensive research, the mechanisms behind the recovery process, where infective juveniles (IJs) transition to a parasitic state upon contact with the host, remain unclear. This study investigates the stimulatory effect of insect-derived materials on the recovery of Heterorhabditis bacteriophora IJs. Three materials from Galleria mellonella larvae-bioactive homogenates from live and frozen larvae, and heat-inactivated homogenate-were tested, along with non-host stimuli including filtered water and phosphate-buffered saline (PBS). While none of the materials induced complete recovery of IJs, all triggered the release of excreted/secreted products (ESPs), with consistent protein concentrations across treatments. However, mass spectrometry revealed significant differences in ESP protein composition. IJs exposed to PBS released the highest number of proteins, while bioactive homogenates induced the fewest. Proteins linked to host-parasite interactions, such as alpha-2-macroglobulins and trypsin inhibitor-like proteins, were more abundant in ESPs following exposure to insect-derived materials and PBS. Interestingly, nematodes exposed to water released a substantial number of proteins, comparable to stimulation by heat-inactivated homogenates, though their protein profiles were distinct, reflecting stress responses in the former and host-parasite interaction-related proteins in the latter. Our findings demonstrate that both host-derived and non-biological stimuli can trigger IJs recovery and ESPs release, underscoring the complexity of host-nematode interactions. These results provide novel insights into molecular mechanisms underlying H. bacteriophora parasitism and may contribute to optimizing biocontrol strategies through a better understanding of nematode activation and released ESPs.
- MeSH
- biologická kontrola škůdců MeSH
- interakce hostitele a parazita MeSH
- larva parazitologie MeSH
- můry parazitologie MeSH
- proteiny červů * metabolismus MeSH
- Rhabditida * MeSH
- Rhabditoidea * metabolismus fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- proteiny červů * MeSH
The honey bee, Apis mellifera L., is one of the main pollinators worldwide. In a temperate climate, seasonality affects the life span, behavior, physiology, and immunity of honey bees. In consequence, it impacts their interaction with pathogens and parasites. In this study, we used Bayesian statistics and modeling to examine the immune response dynamics of summer and winter honey bee workers after injection with the heat-killed bacteria Serratia marcescens, an opportunistic honey bee pathogen. We investigated the humoral and cellular immune response at the transcriptional and functional levels using qPCR of selected immune genes, antimicrobial activity assay, and flow cytometric analysis of hemocyte concentration. Our data demonstrate increased antimicrobial activity at transcriptional and functional levels in summer and winter workers after injection, with a stronger immune response in winter bees. On the other hand, an increase in hemocyte concentration was observed only in the summer bee population. Our results indicate that the summer population mounts a cellular response when challenged with heat-killed S. marcescens, while winter honey bees predominantly rely on humoral immune reactions. We created a model describing the honey bee immune response dynamics to bacteria-derived components by applying Bayesian statistics to our data. This model can be employed in further research and facilitate the investigating of the honey bee immune system and its response to pathogens.
Introduction. The fungal pathogen Aspergillus fumigatus can induce prolonged colonization of the lungs of susceptible patients, resulting in conditions such as allergic bronchopulmonary aspergillosis and chronic pulmonary aspergillosis.Hypothesis. Analysis of the A. fumigatus secretome released during sub-lethal infection of G. mellonella larvae may give an insight into products released during prolonged human colonisation.Methodology. Galleria mellonella larvae were infected with A. fumigatus, and the metabolism of host carbohydrate and proteins and production of fungal virulence factors were analysed. Label-free qualitative proteomic analysis was performed to identify fungal proteins in larvae at 96 hours post-infection and also to identify changes in the Galleria proteome as a result of infection.Results. Infected larvae demonstrated increasing concentrations of gliotoxin and siderophore and displayed reduced amounts of haemolymph carbohydrate and protein. Fungal proteins (399) were detected by qualitative proteomic analysis in cell-free haemolymph at 96 hours and could be categorized into seven groups, including virulence (n = 25), stress response (n = 34), DNA repair and replication (n = 39), translation (n = 22), metabolism (n = 42), released intracellular (n = 28) and cellular development and cell cycle (n = 53). Analysis of the Gallerial proteome at 96 hours post-infection revealed changes in the abundance of proteins associated with immune function, metabolism, cellular structure, insect development, transcription/translation and detoxification.Conclusion. Characterizing the impact of the fungal secretome on the host may provide an insight into how A. fumigatus damages tissue and suppresses the immune response during long-term pulmonary colonization.
- Klíčová slova
- Aspergillus, Galleria mellonella, fungal–host interactions, gliotoxin, proteomics,
- MeSH
- Aspergillus fumigatus * metabolismus MeSH
- aspergilóza mikrobiologie metabolismus MeSH
- faktory virulence metabolismus MeSH
- fungální proteiny * metabolismus genetika MeSH
- hemolymfa mikrobiologie metabolismus MeSH
- larva * mikrobiologie MeSH
- můry * mikrobiologie MeSH
- proteom analýza MeSH
- proteomika MeSH
- sekretom metabolismus MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- faktory virulence MeSH
- fungální proteiny * MeSH
- proteom MeSH
The extensive annual loss of honey bees (Apis mellifera L.) represents a global problem affecting agriculture and biodiversity. The parasitic mite Varroa destructor, associated with viral co-infections, plays a key role in this loss. Despite years of intensive research, the complex mechanisms of Varroa - honey bee interaction are still not fully defined. Therefore, this study employed a unique combination of transcriptomic, proteomic, metabolomic, and functional analyses to reveal new details about the effect of Varroa mites and naturally associated factors, including viruses, on honey bees. We focused on the differences between Varroa parasitised and unparasitised ten-day-old worker bees collected before overwintering from the same set of colonies reared without anti-mite treatment. Supplementary comparison to honey bees collected from colonies with standard anti-Varroa treatment can provide further insights into the effect of a pyrethroid flumethrin. Analysis of the honey bees exposed to mite parasitisation revealed alterations in the transcriptome and proteome related to immunity, oxidative stress, olfactory recognition, metabolism of sphingolipids, and RNA regulatory mechanisms. The immune response and sphingolipid metabolism were strongly activated, whereas olfactory recognition and oxidative stress pathways were inhibited in Varroa parasitised honey bees compared to unparasitised ones. Moreover, metabolomic analysis confirmed the depletion of nutrients and energy stores, resulting in a generally disrupted metabolism in the parasitised workers. The combined omics-based analysis conducted on strictly parasitised bees revealed the key molecular components and mechanisms underlying the detrimental effects of Varroa sp. and its associated pathogens. This study provides the theoretical basis and interlinked datasets for further research on honey bee response to biological threats and the development of efficient control strategies against Varroa mites.
- Klíčová slova
- Honey bee, Infestation, Metabolomic, Proteomic, Transcriptomic, Varroa destructor,
- MeSH
- čich MeSH
- proteomika MeSH
- stanovení celkové genové exprese MeSH
- transkriptom MeSH
- Varroidae * fyziologie MeSH
- včely genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In the temperate climates of central Europe and North America, two distinct honeybee (Apis mellifera) populations are found in colonies: short-living summer bees emerge in spring and survive until summer, whereas long-living winter bees emerge in late August and overwinter. Besides the difference in their life spans, each of these populations fulfils a different role in the colonies and individual bees have distinct physiological and immunological adaptations depending on their roles. For instance, winter worker bees have higher vitellogenin levels and larger reserves of nutrients in the fat body than summer bees. The differences between the immune systems of both populations are well described at the constitutive level; however, our knowledge of its inducibility is still very limited. In this study, we focus on the response of 10-day-old honeybee workers to immune challenges triggered in vivo by injecting heat-killed bacteria, with particular focus on honeybees that emerge and live under hive conditions. Responses to bacterial injections differed between summer and winter bees. Winter bees exhibited a more intense response, including higher expression of antimicrobial genes and antimicrobial activity, as well as a significant decrease in vitellogenin gene expression and its concentration in the hemolymph. The intense immune response observed in winter honeybees may contribute to our understanding of the relationships between colony fitness and infection with pathogens, as well as its association with successful overwintering.
- Klíčová slova
- Antimicrobial peptides, Honeybee, Humoral immunity, Immune system, Longevity,
- MeSH
- imunita * MeSH
- roční období MeSH
- včely MeSH
- vitelogeniny * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
- Severní Amerika MeSH
- Názvy látek
- vitelogeniny * MeSH
Entomopathogenic nematodes (EPNs) are efficient insect parasites, that are known for their mutualistic relationship with entomopathogenic bacteria and their use in biocontrol. EPNs produce bioactive molecules referred to as excreted/secreted products (ESPs), which have come to the forefront in recent years because of their role in the process of host invasion and the modulation of its immune response. In the present study, we confirmed the production of ESPs in the EPN Heterorhabditis bacteriophora, and investigated their role in the modulation of the phenoloxidase cascade, one of the key components of the insect immune system. ESPs were isolated from 14- and 21-day-old infective juveniles of H. bacteriophora, which were found to be more virulent than newly emerged nematodes, as was confirmed by mortality assays using Galleria mellonella larvae. The isolated ESPs were further purified and screened for the phenoloxidase-inhibiting activity. In these products, a 38 kDa fraction of peptides was identified as the main candidate source of phenoloxidase-inhibiting compounds. This fraction was further analyzed by mass spectrometry and the de novo sequencing approach. Six peptide sequences were identified in this active ESP fraction, including proteins involved in ubiquitination and the regulation of a Toll pathway, for which a role in the regulation of insect immune response has been proposed in previous studies.
- Klíčová slova
- Galleria mellonella, Heterorhabditis bacteriophora, excreted/secreted products, immunity, melanization, phenoloxidase, virulence,
- Publikační typ
- časopisecké články MeSH
Bumble bees are important pollinators broadly used by farmers in greenhouses and under conditions in which honeybee pollination is limited. As such, bumble bees are increasingly being reared for commercial purposes, which brings into question whether individuals reared under laboratory conditions are fully capable of physiological adaptation to field conditions. To understand the changes in bumble bee organism caused by foraging, we compared the fundamental physiological and immunological parameters of Bombus terrestris workers reared under constant optimal laboratory conditions with workers from sister colonies that were allowed to forage for two weeks in the field. Nutritional status and immune response were further determined in wild foragers of B. terrestris that lived under the constant influence of natural stressors. Both wild and laboratory-reared workers subjected to the field conditions had a lower protein concentration in the hemolymph and increased antimicrobial activity, the detection of which was limited in the non-foragers. However, in most of the tested parameters, specifically the level of carbohydrates, antioxidants, total hemocyte concentration in the hemolymph and melanization response, we did not observe any significant differences between bumble bee workers produced in the laboratory and wild animals, nor between foragers and non-foragers. Our results show that bumble bees reared under laboratory conditions can mount a sufficient immune response to potential pathogens and cope with differential food availability in the field, similarly to the wild bumble bee workers.
- Klíčová slova
- bumble bee, foraging, immunity, laboratory rearing, nutrients, physiology,
- Publikační typ
- časopisecké články MeSH
It has been known for many years that in temperate climates the European honey bee, Apis mellifera, exists in the form of two distinct populations within the year, short-living summer bees and long-living winter bees. However, there is only limited knowledge about the basic biochemical markers of winter and summer populations as yet. Nevertheless, the distinction between these two kinds of bees is becoming increasingly important as it can help beekeepers to estimate proportion of long-living bees in hives and therefore in part predict success of overwintering. To identify markers of winter generations, we employed the continuous long-term monitoring of a single honey bee colony for almost two years, which included measurements of physiological and immunological parameters. The results showed that the total concentration of proteins, the level of vitellogenin, and the antibacterial activity of haemolymph are the best three of all followed parameters that are related to honey bee longevity and can therefore be used as its markers.
- Klíčová slova
- honey bee, immunity, longevity, physiology, seasonal changes,
- Publikační typ
- časopisecké články MeSH
