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Pane C, Manganiello G, Vitti A, Celano R, Piccinelli AL, De Falco E. Phytochemical Extracts of Dittrichia viscosa (L.) Greuter from Agroecological Systems: Seed Antigerminative Properties and Effectiveness in Counteracting Alternaria Leaf Spot Disease on Baby-Leaf Spinach. BIOLOGY 2023; 12:790. [PMID: 37372075 DOI: 10.3390/biology12060790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/27/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023]
Abstract
Dittrichia viscosa (L.) Greuter subsp. viscosa (Asteraceae) is a perennial species naturally distributed in arid and marginal areas whose agroecological cultivation could be a useful innovation to produce quality biomass to extract phenolic-rich phytochemical blends. Here, biomass-yield trends were profiled at different growth stages under direct cropping, and inflorescences, leaves, and stems were submitted to water extraction and hydrodistillation. Then, four extracts were investigated for their biological activities in invitro and in planta assays. Extracts inhibited cress (Lepidium sativum)- and radish (Raphanus sativus)-seed germination and root elongation. All samples showed dose-dependent antifungal activity in the plate experiments, inhibiting up to 65% of the growth of the fungal pathogen Alternaria alternata, a leaf-spot disease agent of baby spinach (Spinacea oleracea). However, only the extracts from dried green parts and fresh inflorescences at the highest concentration significantly reduced (54%) the extent of Alternaria necrosis on baby spinach. UHPLC-HRMS/MS analysis revealed that the main specialized metabolites of the extracts are caffeoyl quinic acids, methoxylated flavonoids, sesquiterpene compounds such as tomentosin, and dicarboxylic acids, which may explain the observed bioactivity. Plant extracts obtained through sustainable methodology can be effective in biological agricultural applications.
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Affiliation(s)
- Catello Pane
- Consiglio per la Ricerca in Agricoltura e L'analisi dell'Economia Agraria (CREA), Centro di Ricerca Orticoltura e Florovivaismo, Via Cavalleggeri 25, 84098 Pontecagnano Faiano, Italy
| | - Gelsomina Manganiello
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, Italy
| | - Antonella Vitti
- School of Agricultural, Forestry, Food and Environmental Sciences, University of Basilicata, Viale dell'Ateneo Lucano 10, 85100 Potenza, Italy
| | - Rita Celano
- Department of Pharmacy, Course of Agriculture, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
- NBFC, National Biodiversity Future Center, 90133 Palermo, Italy
| | - Anna Lisa Piccinelli
- Department of Pharmacy, Course of Agriculture, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
- NBFC, National Biodiversity Future Center, 90133 Palermo, Italy
| | - Enrica De Falco
- Department of Pharmacy, Course of Agriculture, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, Italy
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2
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Palmer-Young EC, Markowitz LM, Grubbs K, Zhang Y, Corona M, Schwarz R, Chen Y, Evans JD. Antiparasitic effects of three floral volatiles on trypanosomatid infection in honey bees. J Invertebr Pathol 2022; 194:107830. [PMID: 36174749 DOI: 10.1016/j.jip.2022.107830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/07/2022] [Accepted: 09/21/2022] [Indexed: 11/18/2022]
Abstract
Trypanosomatid gut parasites are common in pollinators and costly for social bees. The recently described honey bee trypanosomatid Lotmaria passim is widespread, abundant, and correlated with colony losses in some studies. The potential for amelioration of infection by antimicrobial plant compounds has been thoroughly studied for closely related trypanosomatids of humans and is an area of active research in bumble bees, but remains relatively unexplored in honey bees. We recently identified several floral volatiles that inhibited growth of L. passim in vitro. Here, we tested the dose-dependent effects of four such compounds on infection, mortality, and food consumption in parasite-inoculated honey bees. We found that diets containing the monoterpenoid carvacrol and the phenylpropanoids cinnamaldehyde and eugenol at >10-fold the inhibitory concentrations for cell cultures reduced infection, with parasite numbers decreased by >90% for carvacrol and cinnamaldehyde and >99% for eugenol; effects of the carvacrol isomer thymol were non-significant. However, both carvacrol and eugenol also reduced bee survival, whereas parasite inoculation did not, indicating costs of phytochemical exposure that could exceed those of infection itself. To our knowledge, this is the first controlled screening of phytochemicals for effects on honey bee trypanosomatid infection, identifying potential treatments for managed bees afflicted with a newly characterized, cosmopolitan intestinal parasite.
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Affiliation(s)
| | - Lindsey M Markowitz
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA; Department of Biology, University of Maryland, College Park, MD, USA
| | - Kyle Grubbs
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
| | - Yi Zhang
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA; Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, PR China
| | - Miguel Corona
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
| | - Ryan Schwarz
- Department of Biology, Fort Lewis College, Durango, CO, USA
| | - Yanping Chen
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
| | - Jay D Evans
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
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3
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Brown MJF. Complex networks of parasites and pollinators: moving towards a healthy balance. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210161. [PMID: 35491603 DOI: 10.1098/rstb.2021.0161] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Parasites are viewed as a major threat to wild pollinator health. While this may be true for epidemics driven by parasite spillover from managed or invasive species, the picture is more complex for endemic parasites. Wild pollinator species host and share a species-rich, generalist parasite community. In contrast to the negative health impacts that these parasites impose on individual hosts, at a community level they may act to reduce competition from common and abundant pollinator species. By providing rare species with space in which to exist, this will act to support and maintain a diverse and thus healthier pollinator community. At this level, and perhaps paraxodically, parasites may be good for pollinators. This stands in clear contrast to the obvious negative impacts of epidemic and spillover parasites on wild pollinator communities. Research into floral resources that control parasites could be best employed to help design landscapes that provide pollinators with the opportunity to moderate their parasite community, rather than attempting to eliminate specific parasites from wild pollinator communities. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
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Affiliation(s)
- Mark J F Brown
- Centre for Ecology, Evolution and Behaviour, Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham TW20 0EX, UK
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4
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Koch H, Welcome V, Kendal-Smith A, Thursfield L, Farrell IW, Langat MK, Brown MJF, Stevenson PC. Host and gut microbiome modulate the antiparasitic activity of nectar metabolites in a bumblebee pollinator. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210162. [PMID: 35491601 PMCID: PMC9058528 DOI: 10.1098/rstb.2021.0162] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Antimicrobial nectar secondary metabolites can support pollinator health by preventing or reducing parasite infections. To better understand the outcome of nectar metabolite-parasite interactions in pollinators, we determined whether the antiparasitic activity was altered through chemical modification by the host or resident microbiome during gut passage. We investigated this interaction with linden (Tilia spp.) and strawberry tree (Arbutus unedo) nectar compounds. Unedone from A. unedo nectar inhibited the common bumblebee gut parasite Crithidia bombi in vitro and in Bombus terrestris gynes. A compound in Tilia nectar, 1-[4-(1-hydroxy-1-methylethyl)-1,3-cyclohexadiene-1-carboxylate]-6-O-β-d-glucopyranosyl-β-d-glucopyranose (tiliaside), showed no inhibition in vitro at naturally occurring concentrations but reduced C. bombi infections of B. terrestris workers. Independent of microbiome status, tiliaside was deglycosylated during gut passage, thereby increasing its antiparasitic activity in the hindgut, the site of C. bombi infections. Conversely, unedone was first glycosylated in the midgut without influence of the microbiome to unedone-8-O-β-d-glucoside, rendering it inactive against C. bombi, but subsequently deglycosylated by the microbiome in the hindgut, restoring its activity. We therefore show that conversion of nectar metabolites by either the host or the microbiome modulates antiparasitic activity of nectar metabolites. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
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Affiliation(s)
- Hauke Koch
- Royal Botanic Gardens Kew, Kew Green, Richmond, Surrey TW9 3AE, UK
| | - Vita Welcome
- Royal Botanic Gardens Kew, Kew Green, Richmond, Surrey TW9 3AE, UK.,Imperial College, South Kensington, London SW7 2BX, UK
| | - Amy Kendal-Smith
- Royal Botanic Gardens Kew, Kew Green, Richmond, Surrey TW9 3AE, UK.,Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Lucy Thursfield
- Royal Botanic Gardens Kew, Kew Green, Richmond, Surrey TW9 3AE, UK.,John Innes Centre, Norwich, Norfolk NR4 7UH, UK
| | - Iain W Farrell
- Royal Botanic Gardens Kew, Kew Green, Richmond, Surrey TW9 3AE, UK
| | - Moses K Langat
- Royal Botanic Gardens Kew, Kew Green, Richmond, Surrey TW9 3AE, UK
| | - Mark J F Brown
- Centre for Ecology, Evolution and Behaviour, Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Philip C Stevenson
- Royal Botanic Gardens Kew, Kew Green, Richmond, Surrey TW9 3AE, UK.,Natural Resources Institute, University of Greenwich, Greenwich, Kent ME4 4TB, UK
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5
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Fitch G, Figueroa LL, Koch H, Stevenson PC, Adler LS. Understanding effects of floral products on bee parasites: Mechanisms, synergism, and ecological complexity. Int J Parasitol Parasites Wildl 2022; 17:244-256. [PMID: 35299588 PMCID: PMC8920997 DOI: 10.1016/j.ijppaw.2022.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 12/27/2022]
Abstract
Floral nectar and pollen commonly contain diverse secondary metabolites. While these compounds are classically thought to play a role in plant defense, recent research indicates that they may also reduce disease in pollinators. Given that parasites have been implicated in ongoing bee declines, this discovery has spurred interest in the potential for 'medicinal' floral products to aid in pollinator conservation efforts. We review the evidence for antiparasitic effects of floral products on bee diseases, emphasizing the importance of investigating the mechanism underlying antiparasitic effects, including direct or host-mediated effects. We discuss the high specificity of antiparasitic effects of even very similar compounds, and highlight the need to consider how nonadditive effects of multiple compounds, and the post-ingestion transformation of metabolites, mediate the disease-reducing capacity of floral products. While the bulk of research on antiparasitic effects of floral products on bee parasites has been conducted in the lab, we review evidence for the impact of such effects in the field, and highlight areas for future research at the floral product-bee disease interface. Such research has great potential both to enhance our understanding of the role of parasites in shaping plant-bee interactions, and the role of plants in determining bee-parasite dynamics. This understanding may in turn reveal new avenues for pollinator conservation.
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Affiliation(s)
- Gordon Fitch
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Laura L. Figueroa
- Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Hauke Koch
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE, UK
| | - Philip C. Stevenson
- Royal Botanic Gardens, Kew Green, Kew, Richmond, Surrey, TW9 3AE, UK
- Natural Resources Institute, University of Greenwich, Kent, ME4 4TB, UK
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
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6
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Cotter SC, Al Shareefi E. Nutritional ecology, infection and immune defence - exploring the mechanisms. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100862. [PMID: 34952240 DOI: 10.1016/j.cois.2021.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/01/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
Diet can impact the outcome of parasitic infection in three, non-mutually exclusive ways: 1) by changing the physiological environment of the host, such as the availability of key nutritional resources, the presence of toxic dietary chemicals, the pH or osmolality of the blood or gut, 2) by enhancing the immune response and 3) by altering the presence of host microbiota, which help to digest nutrients and are a potential source of antibiotics. We show that there are no clear patterns in the effects of diet across taxa and that good evidence for the mechanisms by which diet exerts its effects are often lacking. More studies are required to understand the mechanisms of action if we are to discern patterns that can be generalised across host and parasite taxa.
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Affiliation(s)
- Sheena C Cotter
- School of Life Sciences, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK.
| | - Ekhlas Al Shareefi
- Dept of Biology, College of Science for Women, University of Babylon, Hillah-Babil, Iraq
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Palmer-Young EC, Schwarz RS, Chen Y, Evans JD. Punch in the gut: Parasite tolerance of phytochemicals reflects host diet. Environ Microbiol 2022; 24:1805-1817. [PMID: 35315572 DOI: 10.1111/1462-2920.15981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 11/30/2022]
Abstract
Gut parasites of plant-eating insects are exposed to antimicrobial phytochemicals that can reduce infection. Trypanosomatid gut parasites infect insects of diverse nutritional ecologies as well as mammals and plants, raising the question of how host diet-associated phytochemicals shape parasite evolution and host specificity. To test the hypothesis that phytochemical tolerance of trypanosomatids reflects the chemical ecology of their hosts, we compared related parasites from honey bees and mosquitoes-hosts that differ in phytochemical consumption-and contrasted our results with previous studies on phylogenetically related, human-parasitic Leishmania. We identified one bacterial and ten plant-derived substances with known antileishmanial activity that also inhibited honey bee parasites associated with colony collapse. Bee parasites exhibited greater tolerance of chrysin-a flavonoid found in nectar, pollen, and plant resin-derived propolis. In contrast, mosquito parasites were more tolerant of cinnamic acid-a product of lignin decomposition present in woody debris-rich larval habitats. Parasites from both hosts tolerated many compounds that inhibit Leishmania, hinting at possible trade-offs between phytochemical tolerance and mammalian infection. Our results implicate the phytochemistry of host diets as a potential driver of insect-trypanosomatid associations, and identify compounds that could be incorporated into colony diets or floral landscapes to ameliorate infection in bees. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Ryan S Schwarz
- Department of Biology, Fort Lewis College, Durango, CO, USA
| | | | - Jay D Evans
- USDA-ARS Bee Research Lab, Beltsville, MD, USA
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Kebede B, Shibeshi W. In vitro antibacterial and antifungal activities of extracts and fractions of leaves of Ricinus communis Linn against selected pathogens. Vet Med Sci 2022; 8:1802-1815. [PMID: 35182460 PMCID: PMC9297757 DOI: 10.1002/vms3.772] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Infectious disease impacts are reduced due to the development of antimicrobial agents. However, the effectiveness of antimicrobial agents is reduced over time because of the emergence of antimicrobial resistance. To overcome these problems, scholars have been searching for alternative medicines. Ricinus communis is used as a traditional treatment for bovine mastitis, wound infection, and other medicinal purposes. OBJECTIVE The objective of the present study was to further evaluate the antimicrobial activities of R. communis leaf extracts and fractions. METHODS R. communis leaves were macerated in methanol and acetone. The methanol extract showed better antimicrobial activity and subjected to further fractionation via increasing polarity of solvents (n-hexane, chloroform, ethyl acetate, and aqueous). Test microorganisms included in the study were six laboratory reference bacteria (Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, Kleibsella pneumoniae, Pseudomonas aeruginosa and Streptococcus pyogenes), two clinical isolate bacteria (E. coli and S. aureus), and Candida albicans. The agar well diffusion method was employed to determine antimicrobial activity. The minimum inhibitory concentrations (MIC) and minimum bactericidal/fungicidal concentrations (MBC/MFC) were determined through broth microdilution. RESULTS The results indicated that the best antimicrobial activity for ethyl acetate fraction ranged from 14.67 mm (clinical E. coli) to 20.33 mm (S. aureus) at 400 mg/ml, however, n-hexane exhibited the lowest antimicrobial activity. Among the tested fractions, ethyl acetate fraction showed the lowest MIC values ranged from 1.5625 mg/ml (S. aureus) to 16.67 mg/ml (Candida albicans). The ethyl acetate fraction showed bactericidal activity against all tested microorganisms. CONCLUSION Hence, ethyl acetate fraction of crude methanol extract exhibited the best antimicrobial activity.
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Affiliation(s)
- Bedaso Kebede
- Department of Animal Products, Veterinary Drug and Animal Feed Quality Assessment Centre of Ethiopian Veterinary Drug and Animal Feed Administration and Control Authority, Addis Ababa, Ethiopia.,Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Workineh Shibeshi
- Department of Pharmacology and Clinical Pharmacy, School of Pharmacy, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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Seshadri A, Bernklau E. Context-Dependent Effect of Dietary Phytochemicals on Honey Bees Exposed to a Pesticide, Thiamethoxam. JOURNAL OF INSECT SCIENCE (ONLINE) 2021; 21:6347255. [PMID: 34374762 PMCID: PMC8353980 DOI: 10.1093/jisesa/ieab053] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Indexed: 05/08/2023]
Abstract
Honey bees continue to face challenges relating to the degradation of natural flowering habitats that limit their access to diverse floral resources. While it is known that nectar and pollen provide macronutrients, flowers also contain secondary metabolites (phytochemicals) that impart benefits including increased longevity, improved gut microbiome abundance, and pathogen tolerance. Our study aims to understand the role of phytochemicals in pesticide tolerance when worker bees were fed with sublethal doses (1 ppb and 10 ppb) of thiamethoxam (TMX), a neonicotinoid, in 20% (w/v) sugar solution supplemented with 25 ppm of phytochemicals-caffeine, kaempferol, gallic acid, or p-coumaric acid, previously shown to have beneficial impacts on bee health. The effect of phytochemical supplementation during pesticide exposure was context-dependent. With 1 ppb TMX, phytochemical supplementation increased longevity but at 10 ppb TMX, longevity was reduced suggesting a negative synergistic effect. Phytochemicals mixed with 1 ppb TMX increased mortality in bees of the forager-age group but with 10 ppb TMX, mortality of the inhive-age group increased, implying the possibility of accumulation effect in lower sublethal doses. Given that the phytochemical composition of pollen and nectar varies between plant species, we suggest that the negative impacts of agrochemicals on honey bees could vary based on the phytochemicals in pollen and nectar of that crop, and hence the effects may vary across crops. Analyzing the phytochemical composition for individual crops may be a necessary first step prior to determining the appropriate dosage of agrochemicals so that harm to bees Apis mellifera L. is minimized while crop pests are effectively controlled.
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Affiliation(s)
- Arathi Seshadri
- Invasive Species and Pollinator Health Unit, USDA ARS/WRRC, Davis, CA, 95616, USA
- Corresponding author, e-mail:
| | - Elisa Bernklau
- Colorado State University, Department of Agricultural Biology, Fort Collins, CO, 80523, USA
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10
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Nectar non-protein amino acids (NPAAs) do not change nectar palatability but enhance learning and memory in honey bees. Sci Rep 2021; 11:11721. [PMID: 34083559 PMCID: PMC8175726 DOI: 10.1038/s41598-021-90895-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/17/2021] [Indexed: 02/04/2023] Open
Abstract
Floral nectar is a pivotal element of the intimate relationship between plants and pollinators. Nectars are composed of a plethora of nutritionally valuable compounds but also hundreds of secondary metabolites (SMs) whose function remains elusive. Here we performed a set of behavioural experiments to study whether five ubiquitous nectar non-protein amino acids (NPAAs: β-alanine, GABA, citrulline, ornithine and taurine) interact with gustation, feeding preference, and learning and memory in Apis mellifera. We showed that foragers were unable to discriminate NPAAs from water when only accessing antennal chemo-tactile information and that freely moving bees did not exhibit innate feeding preferences for NPAAs. Also, NPAAs did not alter food consumption or longevity in caged bees over 10 days. Taken together our data suggest that natural concentrations of NPAAs did not alter nectar palatability to bees. Olfactory conditioning assays showed that honey bees were more likely to learn a scent when it signalled a sucrose reward containing either β-alanine or GABA, and that GABA enhanced specific memory retention. Conversely, when ingested two hours prior to conditioning, GABA, β-alanine, and taurine weakened bees' acquisition performances but not specific memory retention, which was enhanced in the case of β-alanine and taurine. Neither citrulline nor ornithine affected learning and memory. NPAAs in nectars may represent a cooperative strategy adopted by plants to attract beneficial pollinators.
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11
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Folly AJ, Koch H, Farrell IW, Stevenson PC, Brown MJF. Agri-environment scheme nectar chemistry can suppress the social epidemiology of parasites in an important pollinator. Proc Biol Sci 2021; 288:20210363. [PMID: 34034519 PMCID: PMC8150011 DOI: 10.1098/rspb.2021.0363] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/05/2021] [Indexed: 12/20/2022] Open
Abstract
Emergent infectious diseases are one of the main drivers of species loss. Emergent infection with the microsporidian Nosema bombi has been implicated in the population and range declines of a suite of North American bumblebees, a group of important pollinators. Previous work has shown that phytochemicals found in pollen and nectar can negatively impact parasites in individuals, but how this relates to social epidemiology and by extension whether plants can be effectively used as pollinator disease management strategies remains unexplored. Here, we undertook a comprehensive screen of UK agri-environment scheme (AES) plants, a programme designed to benefit pollinators and wider biodiversity in agricultural settings, for phytochemicals in pollen and nectar using liquid chromatography and mass spectrometry. Caffeine, which occurs across a range of plant families, was identified in the nectar of sainfoin (Onobrychis viciifolia), a component of UK AES and a major global crop. We showed that caffeine significantly reduces N. bombi infection intensity, both prophylactically and therapeutically, in individual bumblebees (Bombus terrestris), and, for the first time, that such effects impact social epidemiology, with colonies reared from wild-caught queens having both lower prevalence and intensity of infection. Furthermore, infection prevalence was lower in foraging bumblebees from caffeine-treated colonies, suggesting a likely reduction in population-level transmission. Combined, these results show that N. bombi is less likely to be transmitted intracolonially when bumblebees consume naturally available caffeine, and that this may in turn reduce environmental prevalence. Consequently, our results demonstrate that floral phytochemicals at ecologically relevant concentrations can impact pollinator disease epidemiology and that planting strategies that increase floral abundance to support biodiversity could be co-opted as disease management tools.
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Affiliation(s)
- Arran J. Folly
- Centre for Ecology, Evolution and Behaviour, Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham, UK
| | | | | | - Philip C. Stevenson
- Royal Botanic Gardens, Kew, UK
- Natural Resources Institute, University of Greenwich, Kent, UK
| | - Mark J. F. Brown
- Centre for Ecology, Evolution and Behaviour, Department of Biological Sciences, School of Life Sciences and the Environment, Royal Holloway University of London, Egham, UK
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12
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Manganyi MC, Bezuidenhout CC, Regnier T, Ateba CN. A Chewable Cure "Kanna": Biological and Pharmaceutical Properties of Sceletium tortuosum. Molecules 2021; 26:molecules26092557. [PMID: 33924742 PMCID: PMC8124331 DOI: 10.3390/molecules26092557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/13/2022] Open
Abstract
Sceletium tortuosum (L.) N.E.Br. (Mesembryanthemaceae), commonly known as kanna or kougoed, is an effective indigenous medicinal plant in South Africa, specifically to the native San and Khoikhoi tribes. Today, the plant has gained strong global attraction and reputation due to its capabilities to promote a sense of well-being by relieving stress with calming effects. Historically, the plant was used by native San hunter-gatherers and Khoi people to quench their thirst, fight fatigue and for healing, social, and spiritual purposes. Various studies have revealed that extracts of the plant have numerous biological properties and isolated alkaloids of Sceletium tortuosum are currently being used as dietary supplements for medicinal purposes and food. Furthermore, current research has focused on the commercialization of the plant because of its treatment in clinical anxiety and depression, psychological and psychiatric disorders, improving mood, promoting relaxation and happiness. In addition, several studies have focused on the isolation and characterization of various beneficial bioactive compounds including alkaloids from the Sceletium tortuosum plant. Sceletium was reviewed more than a decade ago and new evidence has been published since 2008, substantiating an update on this South African botanical asset. Thus, this review provides an extensive overview of the biological and pharmaceutical properties of Sceletium tortuosum as well as the bioactive compounds with an emphasis on antimicrobial, anti-inflammatory, anti-oxidant, antidepressant, anxiolytic, and other significant biological effects. There is a need to critically evaluate the bioactivities and responsible bioactive compounds, which might assist in reinforcing and confirming the significant role of kanna in the promotion of healthy well-being in these stressful times.
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Affiliation(s)
- Madira Coutlyne Manganyi
- Department of Biological and Environmental Sciences, Faculty of Natural Sciences, Walter Sisulu University, PBX1, Mthatha 5117, South Africa
- Correspondence:
| | - Cornelius Carlos Bezuidenhout
- Unit for Environmental Sciences and Management, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa;
| | - Thierry Regnier
- Department of Biotechnology and Food Technology, Tshwane University of Technology, Pretoria 0001, South Africa;
| | - Collins Njie Ateba
- Food Security and Safety Niche Area, Faculty of Natural and Agricultural Sciences, North-West University, Mmabatho, Mafikeng 2735, South Africa;
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Isolation and Antimicrobial Activities of Phytochemicals from Parinari curatellifolia (Chrysobalanaceae). Adv Pharmacol Pharm Sci 2021; 2021:8842629. [PMID: 33763648 PMCID: PMC7952164 DOI: 10.1155/2021/8842629] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 01/18/2021] [Accepted: 02/15/2021] [Indexed: 02/02/2023] Open
Abstract
The widespread use of antimicrobial agents to treat infectious diseases has led to the emergence of antibiotic resistant pathogens. Plants have played a central role in combating many ailments in humans, and Parinari curatellifolia has been used for medicinal purposes. Seven extracts from P. curatellifolia leaves were prepared using serial exhaustive extraction of nonpolar to polar solvents. The microbroth dilution method was used to evaluate antimicrobial bioactivities of extracts. Five of the extracts were significantly active against at least one test microbe. Mycobacterium smegmatis was the most susceptible to most extracts. The methanol and ethanol extracts were the most active against M. smegmatis with an MIC of 25 µg/mL. The hexane extract was the most active against Candida krusei with an MIC of 25 µg/mL. None of the extracts significantly inhibited growth of Klebsiella pneumoniae and Staphylococcus aureus. Active extracts were selected for fractionation and isolation of pure compounds using gradient elution column chromatography. TLC analyses was carried out for pooling fractions of similar profiles. A total of 43 pools were obtained from 428 fractions. Pools 7 and 10 were selected for further isolation of single compounds. Four compounds, Pc4963r, Pc4962w, Pc6978p, and Pc6978o, were isolated. Evaluation of antimicrobial activities of Pc4963r, Pc4962w, and Pc6978p showed that the compounds were most active against C. krusei with MFC values ranging from 50 to 100 µg/mL. Only Pc6978p was shown to be pure. Using spectroscopic analyses, the structure of Pc6978p was determined to be β-sitosterol. The antifungal effects of β-sitosterol were evaluated against C. krusei in vitro and on fabrics. Results showed that β-sitosterol reduced the growth of C. krusei attached to Mendy fabric by 83%. Therefore, P. curatellifolia can be a source of lead compounds for prospective development of novel antimicrobial agents. Further work needs to be done to improve the antifungal activity of the isolated compound using quantitative structure-activity relationships.
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Tauber JP, Tozkar CÖ, Schwarz RS, Lopez D, Irwin RE, Adler LS, Evans JD. Colony-Level Effects of Amygdalin on Honeybees and Their Microbes. INSECTS 2020; 11:E783. [PMID: 33187240 PMCID: PMC7698215 DOI: 10.3390/insects11110783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 11/25/2022]
Abstract
Amygdalin, a cyanogenic glycoside, is found in the nectar and pollen of almond trees, as well as in a variety of other crops, such as cherries, nectarines, apples and others. It is inevitable that western honeybees (Apis mellifera) consistently consume amygdalin during almond pollination season because almond crops are almost exclusively pollinated by honeybees. This study tests the effects of a field-relevant concentration of amygdalin on honeybee microbes and the activities of key honeybee genes. We executed a two-month field trial providing sucrose solutions with or without amygdalin ad libitum to free-flying honeybee colonies. We collected adult worker bees at four time points and used RNA sequencing technology and our HoloBee database to assess global changes in microbes and honeybee transcripts. Our hypothesis was that amygdalin will negatively affect bee microbes and possibly immune gene regulation. Using a log2 fold-change cutoff at two and intraday comparisons, we show no large change of bacterial counts, fungal counts or key bee immune gene transcripts, due to amygdalin treatment in relation to the control. However, relatively large titer decreases in the amygdalin treatment relative to the control were found for several viruses. Chronic bee paralysis virus levels had a sharp decrease (-14.4) with titers then remaining less than the control, Black queen cell virus titers were lower at three time points (<-2) and Deformed wing virus titers were lower at two time points (<-6) in amygdalin-fed compared to sucrose-fed colonies. Titers of Lotmaria passim were lower in the treatment group at three of the four dates (<-4). In contrast, Sacbrood virus had two dates with relative increases in its titers (>2). Overall, viral titers appeared to fluctuate more so than bacteria, as observed by highly inconstant patterns between treatment and control and throughout the season. Our results suggest that amygdalin consumption may reduce several honeybee viruses without affecting other microbes or colony-level expression of immune genes.
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Affiliation(s)
- James P. Tauber
- Bee Research Laboratory, Beltsville Agricultural Research Center, US Department of Agriculture, Beltsville, MD 20705, USA; (C.Ö.T.); (R.S.S.); (D.L.)
| | - Cansu Ö. Tozkar
- Bee Research Laboratory, Beltsville Agricultural Research Center, US Department of Agriculture, Beltsville, MD 20705, USA; (C.Ö.T.); (R.S.S.); (D.L.)
- Department of Agricultural Biotechnology, Faculty of Agriculture, Yüzüncü Yıl University, Van 65000, Turkey
| | - Ryan S. Schwarz
- Bee Research Laboratory, Beltsville Agricultural Research Center, US Department of Agriculture, Beltsville, MD 20705, USA; (C.Ö.T.); (R.S.S.); (D.L.)
- Department of Biology, Fort Lewis College, 1000 Rim Drive, Durango, CO 81301, USA
| | - Dawn Lopez
- Bee Research Laboratory, Beltsville Agricultural Research Center, US Department of Agriculture, Beltsville, MD 20705, USA; (C.Ö.T.); (R.S.S.); (D.L.)
| | - Rebecca E. Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA;
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA;
| | - Jay D. Evans
- Bee Research Laboratory, Beltsville Agricultural Research Center, US Department of Agriculture, Beltsville, MD 20705, USA; (C.Ö.T.); (R.S.S.); (D.L.)
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Hsieh EM, Berenbaum MR, Dolezal AG. Ameliorative Effects of Phytochemical Ingestion on Viral Infection in Honey Bees. INSECTS 2020; 11:insects11100698. [PMID: 33066263 PMCID: PMC7602108 DOI: 10.3390/insects11100698] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/25/2020] [Accepted: 10/06/2020] [Indexed: 01/08/2023]
Abstract
Simple Summary Virus infection is among the many stressors honey bees are experiencing in the modern agricultural landscape. Although some promising treatments are currently under development, no reliable cure currently exists. Here, we investigated the effects of various phytochemicals (plant-produced chemical compounds) on the survivorship of virus infected honey bees. Our results showed that, when consumed at natural concentrations like those found in flowers, caffeine is capable of significantly reducing the mortality of infected bees. It is important to note that caffeine did not clear the infected bees of all viruses and should, therefore, not be considered a virus cure. Rather, caffeine represents a potential antiviral therapeutic agent that should be studied further to improve understanding of virus-phytochemical interactions. Abstract Honey bee viruses are capable of causing a wide variety of devastating effects, but effective treatments have yet to be discovered. Phytochemicals represent a broad range of substances that honey bees frequently encounter and consume, many of which have been shown to improve honey bee health. However, their effect on bee viruses is largely unknown. Here, we tested the therapeutic effectiveness of carvacrol, thymol, p-coumaric acid, quercetin, and caffeine on viral infection by measuring their ability to improve survivorship in honey bees inoculated with Israeli acute paralysis virus (IAPV) using high-throughput cage bioassays. Among these candidates, caffeine was the only phytochemical capable of significantly improving survivorship, with initial screening showing that naturally occurring concentrations of caffeine (25 ppm) were sufficient to produce an ameliorative effect on IAPV infection. Consequently, we measured the scope of caffeine effectiveness in bees inoculated and uninoculated with IAPV by performing the same type of high-throughput bioassay across a wider range of caffeine concentrations. Our results indicate that caffeine may provide benefits that scale with concentration, though the exact mechanism by which caffeine ingestion improves survivorship remains uncertain. Caffeine therefore has the potential to act as an accessible and inexpensive method of treating viral infections, while also serving as a tool to further understanding of honey bee–virus interactions at a physiological and molecular level.
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Pane C, Caputo M, Francese G, Manganiello G, Lo Scalzo R, Mennella G, Zaccardelli M. Managing Rhizoctonia Damping-Off of Rocket ( Eruca sativa) Seedlings by Drench Application of Bioactive Potato Leaf Phytochemical Extracts. BIOLOGY 2020; 9:biology9090270. [PMID: 32899876 PMCID: PMC7564358 DOI: 10.3390/biology9090270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 12/25/2022]
Abstract
Plants produce a huge array of secondary metabolites that play a key role in defense mechanisms against detrimental microorganisms and herbivores, and represent a suitable alternative to synthetic fungicides in sustainable agriculture. In this work, twelve crude hydroethanolic extracts derived from leaves of different potato cultivars were chemically characterized by LC/MS and their antioxidant properties were investigated in vitro. Furthermore, the biological activity against the fungal pathogen Rhizoctonia solani was evaluated both in vitro and in vivo. Extracts showed the ability to inhibit R. solani growth in vitro and significantly reduced damping-off incidence in in vivo experiments. Furthermore, R. solani mycelia exposed to the extracts showed an altered morphology (low translucency, irregular silhouette, and cytoplasmatic content coagulation) compared to the untreated control in light microscopy examination. Principal component analysis conducted on identified chemical compounds highlighted significant metabolic variations across the different extracts. In particular, those that inhibited most of the growth of the pathogen were found to be enriched in α-chaconine or α-solanine content, indicating that their biological activity is affected by the abundance of these metabolites. These results clearly indicated that plant-derived compounds represent a suitable alternative to chemicals and could lead to the development of new formulates for sustainable control of plant diseases.
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Affiliation(s)
- Catello Pane
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Orticoltura e Florovivaismo, via dei Cavalleggeri 25, I-84098 Pontecagnano Faiano, Italy; (M.C.); (G.F.); (G.M.); (G.M.); (M.Z.)
- Correspondence:
| | - Michele Caputo
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Orticoltura e Florovivaismo, via dei Cavalleggeri 25, I-84098 Pontecagnano Faiano, Italy; (M.C.); (G.F.); (G.M.); (G.M.); (M.Z.)
| | - Gianluca Francese
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Orticoltura e Florovivaismo, via dei Cavalleggeri 25, I-84098 Pontecagnano Faiano, Italy; (M.C.); (G.F.); (G.M.); (G.M.); (M.Z.)
| | - Gelsomina Manganiello
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Orticoltura e Florovivaismo, via dei Cavalleggeri 25, I-84098 Pontecagnano Faiano, Italy; (M.C.); (G.F.); (G.M.); (G.M.); (M.Z.)
| | - Roberto Lo Scalzo
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Ingegneria e Trasformazioni Agroalimentari, via Venezian 26, I-20133 Milano, Italy;
| | - Giuseppe Mennella
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Orticoltura e Florovivaismo, via dei Cavalleggeri 25, I-84098 Pontecagnano Faiano, Italy; (M.C.); (G.F.); (G.M.); (G.M.); (M.Z.)
| | - Massimo Zaccardelli
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Orticoltura e Florovivaismo, via dei Cavalleggeri 25, I-84098 Pontecagnano Faiano, Italy; (M.C.); (G.F.); (G.M.); (G.M.); (M.Z.)
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Ruedenauer FA, Sydow D, Spaethe J, Leonhardt SD. Young bumblebees may rely on both direct pollen cues and early experience when foraging. Proc Biol Sci 2020; 287:20201615. [PMID: 32842923 DOI: 10.1098/rspb.2020.1615] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An adequate supply of macro- and micronutrients determines health and reproductive success in most animals. Many bee species, for example, collect nectar and pollen to satisfy their demands for carbohydrates, protein and fat, respectively. Bees can assess the quality of pollen by feeding on it, but also pre-digestively by means of chemotactile assessment. Whether they additionally use larval nutritional experience, as has been shown for Drosophila melanogaster and Bombyx mori, is unknown. In this study, we tested whether pollen selection of bumblebee foragers is affected by nutritional experience (acquired before the onset of foraging) or solely by food quality. Bumblebee larvae were fed with one out of three different pollen blends. As adults, they were offered all three blends when they started foraging for the first time. We found all treatment groups to prefer one out of the three blends. This blend provided the highest nutritional quality and increased the bees' lifespan, as shown by feeding studies with microcolonies. Besides, bees also chose the pollen blend fed during their larval stage more often than expected, indicating a significant effect of pre-foraging experience on adult pollen foraging behaviour. The combination of both direct pollen quality assessment and pre-foraging experience (i.e. during the larval phase or as early imagines) seems to allow foraging bumblebees to efficiently select the most suitable pollen for their colony.
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Affiliation(s)
- Fabian A Ruedenauer
- Department of Animal Ecology and Tropical Biology, Biozentrum, University of Würzburg, Wurzburg, Germany.,Plant-Insect-Interactions Group, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - David Sydow
- Department of Animal Ecology and Tropical Biology, Biozentrum, University of Würzburg, Wurzburg, Germany
| | - Johannes Spaethe
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Wurzburg, Germany
| | - Sara D Leonhardt
- Department of Animal Ecology and Tropical Biology, Biozentrum, University of Würzburg, Wurzburg, Germany.,Plant-Insect-Interactions Group, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
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Sharma A, Shivaprasad D, Chauhan K, Taneja NK. Control of E. coli growth and survival in Indian soft cheese (paneer) using multiple hurdles: Phytochemicals, temperature and vacuum. Lebensm Wiss Technol 2019. [DOI: 10.1016/j.lwt.2019.108350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Szawarski N, Saez A, Domínguez E, Dickson R, De Matteis Á, Eciolaza C, Justel M, Aliano A, Solar P, Bergara I, Pons C, Bolognesi A, Carna G, Garcia W, Garcia O, Eguaras M, Lamattina L, Maggi M, Negri P. Effect of Abscisic Acid (ABA) Combined with Two Different Beekeeping Nutritional Strategies to Confront Overwintering: Studies on Honey Bees' Population Dynamics and Nosemosis. INSECTS 2019; 10:insects10100329. [PMID: 31581467 PMCID: PMC6835648 DOI: 10.3390/insects10100329] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/06/2019] [Accepted: 09/07/2019] [Indexed: 12/29/2022]
Abstract
In temperate climates, beekeeping operations suffer colony losses and colony depopulation of Apis mellifera during overwintering, which are associated with biotic and abiotic stressors that impact bees’ health. In this work, we evaluate the impacts of abscisic acid (ABA) dietary supplementation on honey bee colonies kept in Langstroth hives. The effects of ABA were evaluated in combination with two different beekeeping nutritional strategies to confront overwintering: “honey management” and “syrup management”. Specifically, we evaluated strength parameters of honey bee colonies (adult bee and brood population) and the population dynamics of Nosema (prevalence and intensity) associated with both nutritional systems and ABA supplementation during the whole study (late autumn-winter-early spring). The entire experiment was designed and performed with a local group of beekeepers, “Azahares del sudeste”, who showed interest in answering problems associated with the management of honey bee colonies during the winter. The results indicated that the ABA supplementation had positive effects on the population dynamics of the A. mellifera colonies during overwintering and on the nosemosis at colony level (prevalence) in both nutritional strategies evaluated.
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Affiliation(s)
- Nicolás Szawarski
- Centro de Investigación en Abejas Sociales (CIAS) (IIPROSAM-CONICET), Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Mar del Plata CP 7600, Argentina.
| | - Agustín Saez
- INIBIOMA, Universidad Nacional del Comahue, (CONICET), Quintral 1250, Bariloche 8400, Argentina
| | - Enzo Domínguez
- Centro de Investigación en Abejas Sociales (CIAS) (IIPROSAM-CONICET), Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Mar del Plata CP 7600, Argentina
| | - Rachel Dickson
- Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO 81224, USA
| | - Ángela De Matteis
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Carlos Eciolaza
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Marcelino Justel
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Alfredo Aliano
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Pedro Solar
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Ignacio Bergara
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Claudia Pons
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Aldo Bolognesi
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Gabriel Carna
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Walter Garcia
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Omar Garcia
- Beekeeper from Azahares del Sudeste association, Instituto Nacional de Tecnología Agropecuaria (INTA), Mar del Plata CP 7600, Argentina
| | - Martin Eguaras
- Centro de Investigación en Abejas Sociales (CIAS) (IIPROSAM-CONICET), Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Mar del Plata CP 7600, Argentina
| | - Lorenzo Lamattina
- Instituto de Investigaciones Biológicas (IIB-CONICET), Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Mar del Plata CP 7600, Argentina
| | - Matías Maggi
- Centro de Investigación en Abejas Sociales (CIAS) (IIPROSAM-CONICET), Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Mar del Plata CP 7600, Argentina
| | - Pedro Negri
- Centro de Investigación en Abejas Sociales (CIAS) (IIPROSAM-CONICET), Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Mar del Plata CP 7600, Argentina
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Davis JK, Aguirre LA, Barber NA, Stevenson PC, Adler LS. From plant fungi to bee parasites: mycorrhizae and soil nutrients shape floral chemistry and bee pathogens. Ecology 2019; 100:e02801. [PMID: 31234229 PMCID: PMC6773465 DOI: 10.1002/ecy.2801] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/16/2019] [Accepted: 05/28/2019] [Indexed: 12/19/2022]
Abstract
Bee populations have experienced declines in recent years, due in part to increased disease incidence. Multiple factors influence bee-pathogen interactions, including nectar and pollen quality and secondary metabolites. However, we lack an understanding of how plant interactions with their environment shape bee diet quality. We examined how plant interactions with the belowground environment alter floral rewards and, in turn, bee-pathogen interactions. Soil-dwelling mycorrhizal fungi are considered plant mutualists, although the outcome of the relationship depends on environmental conditions such as nutrients. In a 2 × 2 factorial design, we asked whether mycorrhizal fungi and nutrients affect concentrations of nectar and pollen alkaloids (anabasine and nicotine) previously shown to reduce infection by the gut pathogen Crithidia in the native bumble bee Bombus impatiens. To ask how plant interactions affect this common bee pathogen, we fed pollen and nectar from our treatment plants, and from a wildflower pollen control with artificial nectar, to bees infected with Crithidia. Mycorrhizal fungi and fertilizer both influenced flowering phenology and floral chemistry. While we found no anabasine or nicotine in nectar, high fertilizer increased anabasine and nicotine in pollen. Arbuscular mycorrhizal fungi (AMF) decreased nicotine concentrations, but the reduction due to AMF was stronger in high than low-nutrient conditions. AMF and nutrients also had interactive effects on bee pathogens via changes in nectar and pollen. High fertilizer reduced Crithidia cell counts relative to low fertilizer in AMF plants, but increased Crithidia in non-AMF plants. These results did not correspond with effects of fertilizer and AMF on pollen alkaloid concentrations, suggesting that other components of pollen or nectar were affected by treatments and shaped pathogen counts. Our results indicate that soil biotic and abiotic environment can alter bee-pathogen interactions via changes in floral rewards, and underscore the importance of integrative studies to predict disease dynamics and ecological outcomes.
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Affiliation(s)
- Julie K. Davis
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA
- Department of Entomology, Cornell University, Ithaca, NY 14850, USA
| | - Luis A. Aguirre
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Nicholas A. Barber
- Department of Biological Sciences, San Diego State University, San Diego, CA 92182, USA
| | - Philip C. Stevenson
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey TW9 3AB, UK
- Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK
| | - Lynn S. Adler
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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21
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de Roode JC, Hunter MD. Self-medication in insects: when altered behaviors of infected insects are a defense instead of a parasite manipulation. CURRENT OPINION IN INSECT SCIENCE 2019; 33:1-6. [PMID: 31358187 DOI: 10.1016/j.cois.2018.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/05/2018] [Accepted: 12/07/2018] [Indexed: 06/10/2023]
Abstract
Studies have demonstrated that medication behaviors by insects are much more common than previously thought. Bees, ants, flies, and butterflies can use a wide range of toxic and nutritional compounds to medicate themselves or their genetic kin. Medication occurs either in response to active infection (therapy) or high infection risk (prophylaxis), and can be used to increase resistance or tolerance to infection. While much progress has been made over the last few years, there are also key areas that require in-depth investigation. These include quantifying the costs of medication, especially at the colony level of social insects, and formulating theoretical models that can predict the role of infection risk in driving micro-evolutionary and macro-evolutionary patterns of animal medication behaviors.
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Affiliation(s)
- Jacobus C de Roode
- Department of Biology, Emory University, 1510 Clifton Road, Atlanta, GA 30322, United States.
| | - Mark D Hunter
- Department of Ecology and Evolutionary Biology, University of Michigan, 1105 N University Avenue, Ann Arbor, MI 48109, United States
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22
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Spivak M, Goblirsch M, Simone-Finstrom M. Social-medication in bees: the line between individual and social regulation. CURRENT OPINION IN INSECT SCIENCE 2019; 33:49-55. [PMID: 31358195 DOI: 10.1016/j.cois.2019.02.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 02/16/2019] [Accepted: 02/23/2019] [Indexed: 06/10/2023]
Abstract
We use the term social-medication to describe the deliberate consumption or use of plant compounds by social insects that are detrimental to a pathogen or parasite at the colony level, result in increased inclusive fitness to the colony, and have potential costs either at the individual or colony level in the absence of parasite infection. These criteria for social-medication differ from those for self-medication in that inclusive fitness costs and benefits are distinguished from individual costs and benefits. The consumption of pollen and nectar may be considered a form of social immunity if they help fight infection, resulting in a demonstrated increase in colony health and survival. However, the dietary use of pollen and nectar per se is likely not a form of social-medication unless there is a detriment or cost to their consumption in the absence of parasite infection, such as when they contain phytochemicals that are toxic at certain doses. We provide examples among social bees (bumblebees, stingless bees and honey bees) in which the consumption or use of plant compounds have a demonstrated role in parasite defense and health of the colony. We indicate where more work is needed to distinguish between prophylactic and therapeutic effects of these compounds, and whether the effects are observed at the individual or colony level.
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Affiliation(s)
- Marla Spivak
- Department of Entomology, 1980 Folwell Ave, University of Minnesota, St Paul, MN, 55108, United States.
| | - Michael Goblirsch
- Department of Entomology, 1980 Folwell Ave, University of Minnesota, St Paul, MN, 55108, United States
| | - Michael Simone-Finstrom
- USDA-ARS, Honey Bee Breeding, Genetics, and Physiology Research, 1157 Ben Hur Rd Baton Rouge, LA, 70820, United States
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Yuan L, Yang X, Yu X, Wu Y, Jiang D. Resistance to insecticides and synergistic and antagonistic effects of essential oils on dimefluthrin toxicity in a field population of Culex quinquefasciatus Say. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:928-936. [PMID: 30597793 DOI: 10.1016/j.ecoenv.2018.11.115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/23/2018] [Accepted: 11/25/2018] [Indexed: 06/09/2023]
Abstract
In this work, we firstly tested five spatial repellent pyrethroids, meperfluthrin, dimefluthrin, heptafluthrin, metofluthrin and transfluthrin, to determine the susceptibility of pyrethroids to field strains of Culex quinquefasciatus using adult topical bioassay. The results showed that though field strains exhibited the highest resistance to dimefluthrin among the selected five pyrethroids, it still can be considered low resistance in the scale of Cui et al. (2006; 2007). Then, the aim of this study was to optimise the synergistic efficacy of essential oils combined with dimefluthrin and explore the major contribution composition of eucalyptus oil, basil oil and cinnamon oil as natural synergist of dimefluthrin against the field populations of C. quinquefasciatus. GC-MS analysis showed 1,8-cineole, eugenol and trans-cinnamaldehyde were the main chemical components of eucalyptus oil, basil oil and cinnamon oil, respectively. The results of bioactivity showed that eucalyptus oil and 1,8-cineole have highly fumigant knock-down activity to the adults, showing KT50 (the median knockdown time) of 5.76 and 4.27 min at the concentration of 24.2 µL/L; basil oil and eugenol, cinnamon oil and trans-cinnamaldehyde have highly fumigant toxicity to the adults, showing LD50 of 1.00 and 0.79, 1.26 and 1.03 µL/L, respectively. Three effective main essential oil components were selected to prepare binary mixtures, which combined with dimefluthrin against the field population of Culex quinquefasciatus. 1,8-cineole+eugenol (9:1, w/w), 1,8-cineole+trans-cinnamaldehyde (1:1, w/w) and trans-cinnamaldehyde+eugenol (9:1, w/w) combined with dimefluthrin (10:1, w/w) were the most synergistic interaction, showed SR (synergistic ratio) values of 1.2471, 1.5709 and 1.1969; KT50 of 11.68, 9.51 and 10.67 min respectively, by quadrate box method. In addition, to validate the stable synergistic interaction of 1,8-cineole+trans-cinnamaldehyde (1:1, w/w) combined with dimefluthrin (10:1, w/w), the SR values were about 1.3, and KT50 values were 38.72-50.26 min by simulated house method. Overall, our results pointed out the promising potential of these essential oils to increase the efficacy of dimefluthrin. It might be expected that these essential oils could be developed to a useful botanical synergist of dimefluthrin for the control of the field populations of C. quinquefasciatus.
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Affiliation(s)
- Liang Yuan
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou 510642, PR China
| | - Xiaodong Yang
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou 510642, PR China
| | - Xihui Yu
- Zhongshan Lanju Daily Chemical Industrial Co., Ltd., Zhongshan 528400, Guangdong, PR China
| | - Yinghua Wu
- Zhongshan Lanju Daily Chemical Industrial Co., Ltd., Zhongshan 528400, Guangdong, PR China
| | - Dingxin Jiang
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, Laboratory of Insect Toxicology, South China Agricultural University, Guangzhou 510642, PR China.
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Synthesis and Characterization of a Bioartificial Polymeric System with Potential Antibacterial Activity: Chitosan-Polyvinyl Alcohol-Ampicillin. Molecules 2018; 23:molecules23123109. [PMID: 30486491 PMCID: PMC6321558 DOI: 10.3390/molecules23123109] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/28/2018] [Accepted: 10/30/2018] [Indexed: 11/21/2022] Open
Abstract
Bio-artificial polymeric systems are a new class of polymeric constituents based on blends of synthetic and natural polymers, designed with the purpose of producing new materials that exhibit enhanced properties with respect to the individual components. In this frame, a combination of polyvinyl alcohol (PVA) and chitosan, blended with a widely used antibiotic, sodium ampicillin, has been developed showing a moderate behavior in terms of antibacterial properties. Thus, aqueous solutions of PVA at 1 wt.% were mixed with acid solutions of chitosan at 1 wt.%, followed by adding ampicillin ranging from 0.3 to 1.0 wt.% related to the total amount of the polymers. The prepared bio-artificial polymeric system was characterized by FTIR, SEM, DSC, contact angle measurements, antibacterial activity against Staphylococcus aureus and Escherichia coli and antibiotic release studies. The statistical significance of the antibacterial activity was determined using a multifactorial analysis of variance with ρ < 0.05 (ANOVA). The characterization techniques did not show alterations in the ampicillin structure and the interactions with polymers were limited to intermolecular forces. Therefore, the antibiotic was efficiently released from the matrix and its antibacterial activity was preserved. The system disclosed moderate antibacterial activity against bacterial strains without adding a high antibiotic concentration. The findings of this study suggest that the system may be effective against healthcare-associated infections, a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications.
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Abstract
Declines in wild and managed bee species richness and abundances have been observed throughout Europe and North America in recent decades. These declines have led to questions regarding pollination of wild and cultivated plants. In response to these concerns, efforts towards the conservation of pollinators have been initiated. Part of this conservation effort should be to provide the basic nutritional needs for bees. Nutrition plays one of the most important roles in bee growth, development, and reproduction. There is a large body of information regarding honey bee nutrition, whereas we lack nutritional information on native wild bees. Our knowledge of bumble bee nutritional needs has increased since the introduction of commercial rearing and sale of certain bumble bee species; however, there is still a lack of basic nutritional guidelines such as minimum dietary needs of proteins, amino acids, lipids, and sterols. The large difference in physiology and life history between honey bees and North American wild bees suggests that their nutritional requirements could be quite different.
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Wiese N, Fischer J, Heidler J, Lewkowski O, Degenhardt J, Erler S. The terpenes of leaves, pollen, and nectar of thyme (Thymus vulgaris) inhibit growth of bee disease-associated microbes. Sci Rep 2018; 8:14634. [PMID: 30279427 PMCID: PMC6168512 DOI: 10.1038/s41598-018-32849-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 09/17/2018] [Indexed: 12/21/2022] Open
Abstract
Honey bees are highly prone to infectious diseases, causing colony losses in the worst case. However, they combat diseases through a combination of their innate immune system and social defence behaviours like foraging for health-enhancing plant products (e.g. nectar, pollen and resin). Plant secondary metabolites are not only highly active against bacteria and fungi, they might even enhance selective foraging and feeding decisions in the colony. Here, we tested six major plant terpenes and their corresponding acetates, characterizing six natural Thymus vulgaris chemotypes, for their antimicrobial activity on bacteria associated with European foulbrood. Comparison of the inhibitory activity revealed the highest activity for carvacrol and thymol whereas the acetates mostly did not inhibit bacterial growth. All terpenes and acetates are present in the nectar and pollen of thyme, with pollen containing concentrations higher by several orders of magnitude. The physiological response was tested on forager and freshly emerged bees by means of antennal electroantennography. Both responded much stronger to geraniol and trans-sabinene hydrate compared to carvacrol and thymol. In conclusion, bee-forageable thyme product terpenes (mainly from pollen) yield effective antibiotic activity by reducing the growth of bee disease-associated bacteria and can be detected with different response levels by the honey bees' antennae. This is a further step forward in understanding the complex pathogen-pollinator-plant network.
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Affiliation(s)
- Natalie Wiese
- Institute of Pharmacy, Pharmaceutical Biotechnology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 8, 06120, Halle, Saale, Germany
| | - Juliane Fischer
- Institute of Biology, Molecular Ecology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, 06120, Halle, Saale, Germany
| | - Jenifer Heidler
- Institute of Biology, Molecular Ecology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, 06120, Halle, Saale, Germany
| | - Oleg Lewkowski
- Institute of Biology, Molecular Ecology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, 06120, Halle, Saale, Germany
| | - Jörg Degenhardt
- Institute of Pharmacy, Pharmaceutical Biotechnology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 8, 06120, Halle, Saale, Germany
| | - Silvio Erler
- Institute of Biology, Molecular Ecology, Martin-Luther-University Halle-Wittenberg, Hoher Weg 4, 06120, Halle, Saale, Germany.
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Abstract
Gut symbionts can augment resistance to pathogens by stimulating host-immune responses, competing for space and nutrients, or producing antimicrobial metabolites. Gut microbiota of social bees, which pollinate many crops and wildflowers, protect hosts against diverse infections and might counteract pathogen-related bee declines. Bumble bee gut microbiota, and specifically abundance of Lactobacillus 'Firm-5' bacteria, can enhance resistance to the trypanosomatid parasite Crithidia bombi. However, the mechanism underlying this effect remains unknown. We hypothesized that the Firm-5 bacterium Lactobacillus bombicola, which produces lactic acid, inhibits C. bombi via pH-mediated effects. Consistent with our hypothesis, L. bombicola spent medium inhibited C. bombi growth via reduction in pH that was both necessary and sufficient for inhibition. Inhibition of all parasite strains occurred within the pH range documented in honey bees, though sensitivity to acidity varied among strains. Spent medium was slightly more potent than HCl, d- and l-lactic acids for a given pH, suggesting that other metabolites also contribute to inhibition. Results implicate symbiont-mediated reduction in gut pH as a key determinant of trypanosomatid infection in bees. Future investigation into in vivo effects of gut microbiota on pH and infection intensity would test the relevance of these findings for bees threatened by trypanosomatids.
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28
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Palmer-Young EC, Calhoun AC, Mirzayeva A, Sadd BM. Effects of the floral phytochemical eugenol on parasite evolution and bumble bee infection and preference. Sci Rep 2018; 8:2074. [PMID: 29391545 PMCID: PMC5794921 DOI: 10.1038/s41598-018-20369-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 01/17/2018] [Indexed: 11/09/2022] Open
Abstract
Ecological and evolutionary pressures on hosts and parasites jointly determine infection success. In pollinators, parasite exposure to floral phytochemicals may influence between-host transmission and within-host replication. In the bumble bee parasite Crithidia bombi, strains vary in phytochemical resistance, and resistance increases under in vitro selection, implying that resistance/infectivity trade-offs could maintain intraspecific variation in resistance. We assessed costs and benefits of in vitro selection for resistance to the floral phytochemical eugenol on C. bombi infection in Bombus impatiens fed eugenol-rich and eugenol-free diets. We also assessed infection-induced changes in host preferences for eugenol. In vitro, eugenol-exposed cells initially increased in size, but normalized during adaptation. Selection for eugenol resistance resulted in considerable (55%) but non-significant reductions in infection intensity; bee colony and body size were the strongest predictors of infection. Dietary eugenol did not alter infection, and infected bees preferred eugenol-free over eugenol-containing solutions. Although direct effects of eugenol exposure could influence between-host transmission at flowers, dietary eugenol did not ameliorate infection in bees. Limited within-host benefits of resistance, and possible trade-offs between resistance and infectivity, may relax selection for eugenol resistance and promote inter-strain variation in resistance. However, infection-induced dietary shifts could influence pollinator-mediated selection on floral traits.
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Affiliation(s)
- Evan C Palmer-Young
- Organismic & Evolutionary Biology Graduate Program, University of Massachusetts at Amherst, Amherst, Massachusetts, 01003, United States.
| | - Austin C Calhoun
- School of Biological Sciences, Illinois State University, Normal, Illinois, 61790, United States
| | - Anastasiya Mirzayeva
- Department of Biology, University of Massachusetts at Amherst, Amherst, Massachusetts, 01003, United States
| | - Ben M Sadd
- School of Biological Sciences, Illinois State University, Normal, Illinois, 61790, United States
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Palmer-Young EC, Tozkar CÖ, Schwarz RS, Chen Y, Irwin RE, Adler LS, Evans JD. Nectar and Pollen Phytochemicals Stimulate Honey Bee (Hymenoptera: Apidae) Immunity to Viral Infection. JOURNAL OF ECONOMIC ENTOMOLOGY 2017; 110:1959-1972. [PMID: 28981688 DOI: 10.1093/jee/tox193] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Indexed: 05/10/2023]
Affiliation(s)
| | - Cansu Ö Tozkar
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
| | - Ryan S Schwarz
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
| | - Yanping Chen
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
| | - Rebecca E Irwin
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695
| | - Lynn S Adler
- Department of Biology, University of Massachusetts, Amherst, MA
| | - Jay D Evans
- Bee Research Lab, Agricultural Research Service, US Department of Agriculture, Beltsville, MD
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30
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Koch H, Brown MJ, Stevenson PC. The role of disease in bee foraging ecology. CURRENT OPINION IN INSECT SCIENCE 2017; 21:60-67. [PMID: 28822490 DOI: 10.1016/j.cois.2017.05.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/03/2017] [Accepted: 05/10/2017] [Indexed: 06/07/2023]
Abstract
Diseases have important but understudied effects on bee foraging ecology. Bees transmit and contract diseases on flowers, but floral traits including plant volatiles and inflorescence architecture may affect transmission. Diseases spill over from managed or invasive pollinators to native wild bee species, and impacts of emerging diseases are of particular concern, threatening pollinator populations and pollination services. Here we review how parasites can alter the foraging behaviour of bees by changing floral preferences and impairing foraging efficiency. We also consider how changes to pollinator behaviours alter or reduce pollination services. The availability of diverse floral resources can, however, ameliorate bee diseases and their impacts through better nutrition and antimicrobial effects of plant compounds in pollen and nectar.
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Affiliation(s)
| | - Mark Jf Brown
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK
| | - Philip C Stevenson
- Royal Botanic Gardens, Kew, Surrey, UK; Natural Resources Institute, University of Greenwich, Kent, UK
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31
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Shikano I. Evolutionary Ecology of Multitrophic Interactions between Plants, Insect Herbivores and Entomopathogens. J Chem Ecol 2017; 43:586-598. [DOI: 10.1007/s10886-017-0850-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/06/2017] [Accepted: 05/15/2017] [Indexed: 02/07/2023]
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Palmer-Young EC, Thursfield L. Pollen extracts and constituent sugars increase growth of a trypanosomatid parasite of bumble bees. PeerJ 2017; 5:e3297. [PMID: 28503378 PMCID: PMC5426351 DOI: 10.7717/peerj.3297] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 04/11/2017] [Indexed: 12/20/2022] Open
Abstract
Phytochemicals produced by plants, including at flowers, function in protection against plant diseases, and have a long history of use against trypanosomatid infection. Floral nectar and pollen, the sole food sources for many species of insect pollinators, contain phytochemicals that have been shown to reduce trypanosomatid infection in bumble and honey bees when fed as isolated compounds. Nectar and pollen, however, consist of phytochemical mixtures, which can have greater antimicrobial activity than do single compounds. This study tested the hypothesis that pollen extracts would inhibit parasite growth. Extracts of six different pollens were tested for direct inhibitory activity against cell cultures of the bumble bee trypanosomatid gut parasite Crithidia bombi. Surprisingly, pollen extracts increased parasite growth rather than inhibiting it. Pollen extracts contained high concentrations of sugars, mainly the monosaccharides glucose and fructose. Experimental manipulations of growth media showed that supplemental monosaccharides (glucose and fructose) increased maximum cell density, while a common floral phytochemical (caffeic acid) with inhibitory activity against other trypanosomatids had only weak inhibitory effects on Crithidia bombi. These results indicate that, although pollen is essential for bees and other pollinators, pollen may promote growth of intestinal parasites that are uninhibited by pollen phytochemicals and, as a result, can benefit from the nutrients that pollen provides.
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Affiliation(s)
- Evan C. Palmer-Young
- Organismic and Evolutionary Biology, University of Massachusetts at Amherst, Amherst, MA, United States of America
| | - Lucy Thursfield
- Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom
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33
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Palmer-Young EC, Sadd BM, Irwin RE, Adler LS. Synergistic effects of floral phytochemicals against a bumble bee parasite. Ecol Evol 2017; 7:1836-1849. [PMID: 28331591 PMCID: PMC5355193 DOI: 10.1002/ece3.2794] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 01/02/2017] [Accepted: 01/14/2017] [Indexed: 12/24/2022] Open
Abstract
Floral landscapes comprise diverse phytochemical combinations. Individual phytochemicals in floral nectar and pollen can reduce infection in bees and directly inhibit trypanosome parasites. However, gut parasites of generalist pollinators, which consume nectar and pollen from many plant species, are exposed to phytochemical combinations. Interactions between phytochemicals could augment or decrease effects of single compounds on parasites. Using a matrix of 36 phytochemical treatment combinations, we assessed the combined effects of two floral phytochemicals, eugenol and thymol, against four strains of the bumblebee gut trypanosome Crithidia bombi. Eugenol and thymol had synergistic effects against C. bombi growth across seven independent experiments, showing that the phytochemical combination can disproportionately inhibit parasites. The strength of synergistic effects varied across strains and experiments. Thus, the antiparasitic effects of individual compounds will depend on both the presence of other phytochemicals and parasite strain identity. The presence of synergistic phytochemical combinations could augment the antiparasitic activity of individual compounds for pollinators in diverse floral landscapes.
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Affiliation(s)
| | - Ben M Sadd
- School of Biological Sciences Illinois State University Normal IL USA
| | - Rebecca E Irwin
- Department of Applied Ecology North Carolina State University Raleigh NC USA
| | - Lynn S Adler
- Department of Biology University of Massachusetts at Amherst Amherst MA USA
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