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Fichant A, Lanceleur R, Hachfi S, Brun-Barale A, Blier AL, Firmesse O, Gallet A, Fessard V, Bonis M. New Approach Methods to Assess the Enteropathogenic Potential of Strains of the Bacillus cereus Group, including Bacillus thuringiensis. Foods 2024; 13:1140. [PMID: 38672813 PMCID: PMC11048917 DOI: 10.3390/foods13081140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
Bacillus cereus (Bc) is a wide group of Gram-positive and spore-forming bacteria, known to be the etiological agents of various human infections, primarily food poisoning. The Bc group includes enteropathogenic strains able to germinate in the digestive tract and to produce enterotoxins such as Nhe, Hbl, and CytK. One species of the group, Bacillus thuringiensis (Bt), has the unique feature of producing insecticidal crystals during sporulation, making it an important alternative to chemical pesticides to protect crops from insect pest larvae. Nevertheless, several studies have suggested a link between the ingestion of pesticide strains and human cases of food poisoning, calling their safety into question. Consequently, reliable tools for virulence assessment are worth developing to aid decision making in pesticide regulation. Here, we propose complementary approaches based on two biological models, the human intestinal Caco-2 cell line and the insect Drosophila melanogaster, to assess and rank the enteric virulence potency of Bt strains in comparison with other Bc group members. Using a dataset of 48 Bacillus spp. strains, we showed that some Bc group strains, including Bt, were able to induce cytotoxicity in Caco-2 cells with concomitant release of IL-8 cytokine, a landmark of pro-inflammatory response. In the D. melanogaster model, we were able to sort a panel of 39 strains into four different classes of virulence, ranging from no virulence to strong virulence. Importantly, for the most virulent strains, mortality was associated with a loss of intestinal barrier integrity. Interestingly, although strains can share a common toxinotype, they display different degrees of virulence, suggesting the existence of specific mechanisms of virulence expression in vivo in the intestine.
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Affiliation(s)
- Arnaud Fichant
- Laboratory for Food Safety, University Paris-Est, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 94700 Maisons-Alfort, France; (A.F.); (O.F.)
- Université Côte d’Azur, CNRS, INRAE, ISA, 06903 Sophia-Antipolis, France; (S.H.); (A.B.-B.); (A.G.)
| | - Rachelle Lanceleur
- Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 35306 Fougères, France; (R.L.); (A.-L.B.); (V.F.)
| | - Salma Hachfi
- Université Côte d’Azur, CNRS, INRAE, ISA, 06903 Sophia-Antipolis, France; (S.H.); (A.B.-B.); (A.G.)
| | - Alexandra Brun-Barale
- Université Côte d’Azur, CNRS, INRAE, ISA, 06903 Sophia-Antipolis, France; (S.H.); (A.B.-B.); (A.G.)
| | - Anne-Louise Blier
- Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 35306 Fougères, France; (R.L.); (A.-L.B.); (V.F.)
| | - Olivier Firmesse
- Laboratory for Food Safety, University Paris-Est, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 94700 Maisons-Alfort, France; (A.F.); (O.F.)
| | - Armel Gallet
- Université Côte d’Azur, CNRS, INRAE, ISA, 06903 Sophia-Antipolis, France; (S.H.); (A.B.-B.); (A.G.)
| | - Valérie Fessard
- Fougères Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 35306 Fougères, France; (R.L.); (A.-L.B.); (V.F.)
| | - Mathilde Bonis
- Laboratory for Food Safety, University Paris-Est, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 94700 Maisons-Alfort, France; (A.F.); (O.F.)
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2
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Alkassab AT, Erler S, Steinert M, Pistorius J. Exposure of honey bees to mixtures of microbial biopesticides and their effects on bee survival under laboratory conditions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:26618-26627. [PMID: 38453759 PMCID: PMC11052877 DOI: 10.1007/s11356-024-32753-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 02/29/2024] [Indexed: 03/09/2024]
Abstract
Biopesticides, having as active ingredients viruses, bacteria, or fungi, are developed to substitute or reduce the use of chemical plant protection products in different agrosystems. Though the application of mixtures containing several products is a common practice, interactions between microbial biopesticides and related effects on bees as non-target organisms have not been studied yet. In the current study, we exposed winter bees to five different microbial-based products and their combinations at the maximum recommended application rate to assess their responses. Laboratory oral exposure tests (acute/chronic) to single or binary products were conducted. Survival and food consumption of the tested bees were evaluated over the experimental duration. Our results show that some product combinations have potential additive or synergistic effects on bees, whereas others did not affect the bee's survival compared to the control. Exposure of tested bees to the most critical combination of products containing Bacillus thuringiensis aizawai ABTS-1857 and B. amyloliquefaciens QST 713 strongly resulted in a median lifespan of 4.5 days compared to 8.0 and 8.5 days after exposure to the solo products, respectively. The exposure to inactivated microorganisms by autoclaving them did not differ from their respective uncontaminated negative controls, indicating effects on bee mortality might originate in the treatment with the different microorganisms or their metabolites. Further investigations should be conducted under field conditions to prove the magnitude of observed effects on bee colonies and other bee species.
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Affiliation(s)
- Abdulrahim T Alkassab
- Institute for Bee Protection, Federal Research Centre for Cultivated Plants, Julius Kühn Institute (JKI), Messeweg 11-12, 38104, Braunschweig, Germany.
| | - Silvio Erler
- Institute for Bee Protection, Federal Research Centre for Cultivated Plants, Julius Kühn Institute (JKI), Messeweg 11-12, 38104, Braunschweig, Germany
- Zoological Institute, Technische Universität Braunschweig, Mendelssohnstraße 4, 38106, Brauschweig, Germany
| | - Michael Steinert
- Institut Für Mikrobiologie, Technische Universität Braunschweig, Spielmannstraße 7, 38106, Braunschweig, Germany
| | - Jens Pistorius
- Institute for Bee Protection, Federal Research Centre for Cultivated Plants, Julius Kühn Institute (JKI), Messeweg 11-12, 38104, Braunschweig, Germany
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3
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Huang CK, Lin YN, Huang WS, Senapati S, Chang HC, Sun YM, Huang LF. RNA-based detection of genetically modified plants via current-voltage characteristic measurement. J Biotechnol 2024; 383:27-38. [PMID: 38336281 DOI: 10.1016/j.jbiotec.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/30/2024] [Accepted: 02/05/2024] [Indexed: 02/12/2024]
Abstract
The widespread adoption of genetically modified (GM) crops has escalated concerns about their safety and ethical implications, underscoring the need for efficient GM crop detection methods. Conventional detection methods, such as polymerase chain reaction, can be costly, lab-bound, and time-consuming. To overcome these challenges, we have developed RapiSense, a cost-effective, portable, and sensitive biosensor platform. This sensor generates a measurable voltage shift (0.1-1 V) in the system's current-voltage characteristics, triggered by an increase in membrane's negative charge upon hybridization of DNA/RNA targets with a specific DNA probe. Probes designed to identify the herbicide resistance gene hygromycin phosphotransferase show a detection range from ∼1 nM to ∼10 μM and can discriminate between complementary, non-specific, and mismatched nucleotide targets. The incorporation of a small membrane sensor to detect fragmented RNA samples substantially improve the platform's sensitivity. In this study, RapiSense has been effectively used to detect specific DNA and fragmented RNA in transgenic variants of Arabidopsis, sweet potato, and rice, showcasing its potential for rapid, on-site GM crop screening.
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Affiliation(s)
- Chun-Kai Huang
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China; Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115201, Taiwan, Republic of China
| | - Yi-Nan Lin
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China
| | - Wen-Shan Huang
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China
| | - Satyajyoti Senapati
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Hsueh-Chia Chang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Yi-Ming Sun
- Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China; R&D Center for Membrane Technology, Chung Yuan University, Taoyuan 320071, Taiwan, Republic of China
| | - Li-Fen Huang
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan 320315, Taiwan, Republic of China.
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4
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Babin A, Gatti JL, Poirié M. Bacillus thuringiensis bioinsecticide influences Drosophila oviposition decision. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230565. [PMID: 37650056 PMCID: PMC10465210 DOI: 10.1098/rsos.230565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/10/2023] [Indexed: 09/01/2023]
Abstract
Behavioural avoidance has obvious benefits for animals facing environmental stressors such as pathogen-contaminated foods. Most current bioinsecticides are based on the environmental and opportunistic bacterium Bacillus thuringiensis (Bt) that kills targeted insect pests upon ingestion. While food and oviposition avoidance of Bt bioinsecticide by targeted insect species was reported, this remained to be addressed in non-target organisms, especially those affected by chronic exposure to Bt bioinsecticide such as Drosophila species. Here, using a two-choice oviposition test, we showed that female flies of three Drosophila species (four strains of D. melanogaster, D. busckii and D. suzukii) avoided laying eggs in the presence of Bt var. kurstaki bioinsecticide, with potential benefits for the offspring and female's fitness. Avoidance occurred rapidly, regardless of the fraction of the bioinsecticide suspension (spores and toxin crystals versus soluble toxins/compounds) and independently of the female motivation for egg laying. Our results suggest that, in addition to recent findings of developmental and physiological alterations upon chronic exposure to non-target Drosophila, this bioinsecticide may modify the competitive interactions between Drosophila species in treated areas and the interactions with their associated natural enemies.
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Affiliation(s)
- Aurélie Babin
- Université Côte d'Azur, INRAE, CNRS, Sophia Agrobiotech Institute (ISA), 06903 Sophia Antipolis, France
| | - Jean-Luc Gatti
- Université Côte d'Azur, INRAE, CNRS, Sophia Agrobiotech Institute (ISA), 06903 Sophia Antipolis, France
| | - Marylène Poirié
- Université Côte d'Azur, INRAE, CNRS, Sophia Agrobiotech Institute (ISA), 06903 Sophia Antipolis, France
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5
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Mouawad C, Awad MK, Liegeois S, Ferrandon D, Sanchis-Borja V, El Chamy L. The NF-κB factor Relish is essential for the epithelial defenses protecting against δ-endotoxin dependent effects of Bacillus thuringiensis israelensis infection in the Drosophila model. Res Microbiol 2023; 174:104089. [PMID: 37348743 DOI: 10.1016/j.resmic.2023.104089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 05/29/2023] [Accepted: 06/09/2023] [Indexed: 06/24/2023]
Abstract
Bacillus thuringiensis israelensis is largely regarded as the most selective, safe and ecofriendly biopesticide used for the control of insect vectors of human diseases. Bti enthomopathogenicity relies on the Cry and Cyt δ-endotoxins, produced as crystalline inclusions during sporulation. Insecticidal selectivity of Bti is mainly ascribed to the binding of the Cry toxins to receptors in the gut of target insects. However, the contribution of epithelial defenses in limiting Bti side effects in non-target species remains largely unexplored. Here, taking advantage of the genetically tractable Drosophila melanogaster model and its amenability for deciphering highly conserved innate immune defenses, we unravel a central role of the NF-κB factor Relish in the protection against the effects of ingested Bti spores in a non-susceptible host. Intriguingly, our data indicate that the Bti-induced Relish response is independent of its canonical activation downstream of peptidoglycan sensing and does not involve its longstanding role in the regulation of antimicrobial peptides encoding genes. In contrast, our data highlight a novel enterocyte specific function of Relish that is essential for preventing general septicemia following Bti oral infections strictly when producing δ-endotoxins. Altogether, our data provide novel insights into Bti-hosts interactions of prominent interest for the optimization and sustainability of insects' biocontrol strategies.
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Affiliation(s)
- Carine Mouawad
- Unité de Recherche Environnement, Génomique et Protéomique, Faculté des Sciences, Université Saint-Joseph de Beyrouth-Liban, Mar Roukos, Mkalles, Beirut, Lebanon.
| | - Mireille Kallassy Awad
- Unité de Recherche Environnement, Génomique et Protéomique, Faculté des Sciences, Université Saint-Joseph de Beyrouth-Liban, Mar Roukos, Mkalles, Beirut, Lebanon.
| | - Samuel Liegeois
- Université de Strasbourg, Strasbourg, France; Modèles Insectes de l'Immunité Innée, UPR 9022 du CNRS, Strasbourg, France.
| | - Dominique Ferrandon
- Université de Strasbourg, Strasbourg, France; Modèles Insectes de l'Immunité Innée, UPR 9022 du CNRS, Strasbourg, France.
| | - Vincent Sanchis-Borja
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.
| | - Laure El Chamy
- Unité de Recherche Environnement, Génomique et Protéomique, Faculté des Sciences, Université Saint-Joseph de Beyrouth-Liban, Mar Roukos, Mkalles, Beirut, Lebanon.
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6
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Steinigeweg C, Alkassab AT, Erler S, Beims H, Wirtz IP, Richter D, Pistorius J. Impact of a Microbial Pest Control Product Containing Bacillus thuringiensis on Brood Development and Gut Microbiota of Apis mellifera Worker Honey Bees. MICROBIAL ECOLOGY 2023; 85:1300-1307. [PMID: 35389085 PMCID: PMC10167108 DOI: 10.1007/s00248-022-02004-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 03/28/2022] [Indexed: 05/10/2023]
Abstract
To avoid potential adverse side effects of chemical plant protection products, microbial pest control products (MPCP) are commonly applied as biological alternatives. This study aimed to evaluate the biosafety of a MPCP with the active organism Bacillus thuringiensis ssp. aizawai (strain: ABTS-1857). An in-hive feeding experiment was performed under field-realistic conditions to examine the effect of B. thuringiensis (B. t.) on brood development and the bacterial abundance of the core gut microbiome (Bifidobacterium asteroids, Gilliamella apicola, the group of Lactobacillus and Snodgrasella alvi) in Apis mellifera worker bees. We detected a higher brood termination rate and a non-successful development into worker bees of treated colonies compared to those of the controls. For the gut microbiome, all tested core members showed a significantly lower normalized abundance in bees of the treated colonies than in those of the controls; thus, a general response of the gut microbiome may be assumed. Consequently, colony exposure to B. t. strain ABTS-1857 had a negative effect on brood development under field-realistic conditions and caused dysbiosis of the gut microbiome. Further studies with B. t.-based products, after field-realistic application in bee attractive crops, are needed to evaluate the potential risk of these MPCPs on honey bees.
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Affiliation(s)
| | - Abdulrahim T Alkassab
- Institute for Bee Protection, Julius Kühn-Institut (JKI) - FederalResearch Centre for Cultivated Plants, Braunschweig, Germany.
| | - Silvio Erler
- Institute for Bee Protection, Julius Kühn-Institut (JKI) - FederalResearch Centre for Cultivated Plants, Braunschweig, Germany
| | - Hannes Beims
- Institute for Apiculture, Lower Saxony State Office for Consumer Protection and Food Safety (LAVES), Celle, Germany
| | - Ina P Wirtz
- Institute for Bee Protection, Julius Kühn-Institut (JKI) - FederalResearch Centre for Cultivated Plants, Braunschweig, Germany
| | - Dania Richter
- Institute of Geoecology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Jens Pistorius
- Institute for Bee Protection, Julius Kühn-Institut (JKI) - FederalResearch Centre for Cultivated Plants, Braunschweig, Germany
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7
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Jneid R, Loudhaief R, Zucchini-Pascal N, Nawrot-Esposito MP, Fichant A, Rousset R, Bonis M, Osman D, Gallet A. Bacillus thuringiensis toxins divert progenitor cells toward enteroendocrine fate by decreasing cell adhesion with intestinal stem cells in Drosophila. eLife 2023; 12:e80179. [PMID: 36847614 PMCID: PMC9977296 DOI: 10.7554/elife.80179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 02/05/2023] [Indexed: 03/01/2023] Open
Abstract
Bacillus thuringiensis subsp. kurstaki (Btk) is a strong pathogen toward lepidopteran larvae thanks to specific Cry toxins causing leaky gut phenotypes. Hence, Btk and its toxins are used worldwide as microbial insecticide and in genetically modified crops, respectively, to fight crop pests. However, Btk belongs to the B. cereus group, some strains of which are well known human opportunistic pathogens. Therefore, ingestion of Btk along with food may threaten organisms not susceptible to Btk infection. Here we show that Cry1A toxins induce enterocyte death and intestinal stem cell (ISC) proliferation in the midgut of Drosophila melanogaster, an organism non-susceptible to Btk. Surprisingly, a high proportion of the ISC daughter cells differentiate into enteroendocrine cells instead of their initial enterocyte destiny. We show that Cry1A toxins weaken the E-Cadherin-dependent adherens junction between the ISC and its immediate daughter progenitor, leading the latter to adopt an enteroendocrine fate. Hence, although not lethal to non-susceptible organisms, Cry toxins can interfere with conserved cell adhesion mechanisms, thereby disrupting intestinal homeostasis and endocrine functions.
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Affiliation(s)
- Rouba Jneid
- Universite Cote d'Azur, CNRS, INRAESophia AntipolisFrance
- Faculty of Sciences III and Azm Center for Research in Biotechnology and its Applications, LBA3B, EDST, Lebanese UniversityTripoliLebanon
| | | | | | | | - Arnaud Fichant
- Universite Cote d'Azur, CNRS, INRAESophia AntipolisFrance
- Laboratory for Food Safety, University Paris-Est, French Agency for Food, Environmental and Occupational Health & SafetyMaisons-AlfortFrance
| | | | - Mathilde Bonis
- Laboratory for Food Safety, University Paris-Est, French Agency for Food, Environmental and Occupational Health & SafetyMaisons-AlfortFrance
| | - Dani Osman
- Faculty of Sciences III and Azm Center for Research in Biotechnology and its Applications, LBA3B, EDST, Lebanese UniversityTripoliLebanon
| | - Armel Gallet
- Universite Cote d'Azur, CNRS, INRAESophia AntipolisFrance
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8
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Alkassab AT, Beims H, Janke M, Pistorius J. Determination, distribution, and environmental fate of Bacillus thuringiensis spores in various honeybee matrices after field application as plant protection product. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:25995-26001. [PMID: 35218483 PMCID: PMC8986675 DOI: 10.1007/s11356-022-19414-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/21/2022] [Indexed: 05/14/2023]
Abstract
The increasing use of Bacillus thuringiensis (Bt)-based plant protection products (PPPs) has recently raised some concerns regarding their environmental accumulation and possible chronic exposure of non-target species, including pollinators, to higher than expected doses. The exposure level of such microbial PPPs in bee's matrices under field conditions has not yet been described. Therefore, the current study aims at evaluating the realistic exposure level and comparing the distributions and persistence of Bt spores under field conditions. A field trial with spray application in oilseed rape (Brassica napus) as a representative bee-attractive crop was conducted. During the experimental period, different matrices, including honeybee-collected and -stored matrices as well as bee larvae and dead bees, were collected and analyzed using newly established methods. The concentration of Bt spores in the various matrices was quantified. The results show high levels of Bt spores in honey sac and pollen pellets with reduction over time but no reduction of Bt spores in the stored matrices within the colony, i.e., nectar and bee bread, over time. Our results show for the first time the exposure level of bees to Bt spores under realistic field conditions and are fundamentally important for assessing potential exposure and risks for pollinators.
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Affiliation(s)
- Abdulrahim T Alkassab
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Bee Protection, Braunschweig, Germany.
| | - Hannes Beims
- Lower Saxony State Office for Consumer Protection and Food Safety (LAVES), Institute for Apiculture, Celle, Germany
| | - Martina Janke
- Lower Saxony State Office for Consumer Protection and Food Safety (LAVES), Institute for Apiculture, Celle, Germany
| | - Jens Pistorius
- Julius Kühn-Institut (JKI), Federal Research Centre for Cultivated Plants, Institute for Bee Protection, Braunschweig, Germany
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9
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Moteshareie H, Hassen WM, Vermette J, Dubowski JJ, Tayabali AF. Strategies for capturing Bacillus thuringiensis spores on surfaces of (001) GaAs-based biosensors. Talanta 2022; 236:122813. [PMID: 34635209 DOI: 10.1016/j.talanta.2021.122813] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/18/2021] [Accepted: 08/16/2021] [Indexed: 12/17/2022]
Abstract
Bacillus thuringiensis (Bt) is used as a bioinsecticide since it effectively kills insect larvae. Bt is also genetically similar to Bacillus cereus (Bc), a well recognized foodborne human pathogen; they are both members of the Bacillus cereus group (BC group). Although approved Bt bioinsecticide products have been confirmed to be non-pathogenic to humans, close monitoring of Bt during dissemination is important for cost considerations and to limit impact on biodiversity towards nontarget organisms. As such, developing rapid, sensitive, and specific tools for quantitative detection of Bt spores during and following spray operations is highly desirable. The goals of this study were to investigate commercially available detection reagents for sensitivity and selectivity in detecting Bt spores, and then functionalize a surface of (001) GaAs used in photonic biosensing. To achieve these goals, we (1) screened commercial antibodies for their capacity to bind recombinant proteins from Bt spores, (2) screened antibodies and aptamers for their sensitivity and selectivity against Bt spores, and (3) tested the efficiency of selected antibodies and aptamers in capturing Bt spores on the surface of functionalized GaAs biochips. Seven genes encoding Bt spore proteins were cloned and expressed in Escherichia coli. The binding of each purified spore antigen was tested by commercially available polyclonal and monoclonal antibodies claimed to exclusively target spores. Of the seven targets, Bacillus collagen-like protein A, was the most abundant protein on Bt spores and demonstrated the strongest binding affinity to all test antibodies. The commercial antibodies (Abs) were also tested for specificity to BC Group versus non-BC Group spores. Three of six commercial antibodies showed selectivity to Bt spores, with recombinant Abs providing the most robust lower range of detection (102 to 6 × 103 spores/mL). The sensitivity and selectivity of three published DNA aptamer sequences demonstrated a wide range of detection sensitivity for Bt spores. Two of the three test aptamers also showed reasonable selectivity towards Bt spores while the third demonstrated reactivity to non-BC Group B. megaterium and B. subtilis. Of the reagents tested, a thiolated aptamer and llama recombinant Ab showed highest Bt spore capture efficiency as measured by spore coverage of the GaAs surface. These results confirm that the selected aptamer and llama rAb can be considered strong candidates for the development of GaAs-based biosensing devices.
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Affiliation(s)
- Houman Moteshareie
- Biotechnology Laboratory, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada; Interdisciplinary Institute for Technological Innovation (3IT), CNRS UMI-3463, Laboratory for Quantum Semiconductors and Photon-based BioNanotechnology, Department of Electrical and Computer Engineering, Sherbrooke, Québec, Canada.
| | - Walid M Hassen
- Interdisciplinary Institute for Technological Innovation (3IT), CNRS UMI-3463, Laboratory for Quantum Semiconductors and Photon-based BioNanotechnology, Department of Electrical and Computer Engineering, Sherbrooke, Québec, Canada
| | - Jonathan Vermette
- Interdisciplinary Institute for Technological Innovation (3IT), CNRS UMI-3463, Laboratory for Quantum Semiconductors and Photon-based BioNanotechnology, Department of Electrical and Computer Engineering, Sherbrooke, Québec, Canada
| | - Jan J Dubowski
- Interdisciplinary Institute for Technological Innovation (3IT), CNRS UMI-3463, Laboratory for Quantum Semiconductors and Photon-based BioNanotechnology, Department of Electrical and Computer Engineering, Sherbrooke, Québec, Canada.
| | - Azam F Tayabali
- Biotechnology Laboratory, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada; Interdisciplinary Institute for Technological Innovation (3IT), CNRS UMI-3463, Laboratory for Quantum Semiconductors and Photon-based BioNanotechnology, Department of Electrical and Computer Engineering, Sherbrooke, Québec, Canada.
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10
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Paril JF, Balding DJ, Fournier-Level A. Optimizing sampling design and sequencing strategy for the genomic analysis of quantitative traits in natural populations. Mol Ecol Resour 2021; 22:137-152. [PMID: 34192415 DOI: 10.1111/1755-0998.13458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 05/02/2021] [Accepted: 06/25/2021] [Indexed: 11/27/2022]
Abstract
Mapping the genes underlying ecologically relevant traits in natural populations is fundamental to develop a molecular understanding of species adaptation. Current sequencing technologies enable the characterization of a species' genetic diversity across the landscape or even over its whole range. The relevant capture of the genetic diversity across the landscape is critical for a successful genetic mapping of traits and there are no clear guidelines on how to achieve an optimal sampling and which sequencing strategy to implement. Here we determine, through simulation, the sampling scheme that maximizes the power to map the genetic basis of a complex trait in an outbreeding species across an idealized landscape and draw genomic predictions for the trait, comparing individual and pool sequencing strategies. Our results show that quantitative trait locus detection power and prediction accuracy are higher when more populations over the landscape are sampled and this is more cost-effectively done with pool sequencing than with individual sequencing. Additionally, we recommend sampling populations from areas of high genetic diversity. As progress in sequencing enables the integration of trait-based functional ecology into landscape genomics studies, these findings will guide study designs allowing direct measures of genetic effects in natural populations across the environment.
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Affiliation(s)
- Jefferson F Paril
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
| | - David J Balding
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia.,Melbourne Integrative Genomics, The University of Melbourne, Parkville, Victoria, Australia.,School of Mathematics and Statistics, The University of Melbourne, Parkville, Victoria, Australia
| | - Alexandre Fournier-Level
- School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia.,Melbourne Integrative Genomics, The University of Melbourne, Parkville, Victoria, Australia
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Susceptibility of Drosophila suzukii larvae to the combined administration of the entomopathogens Bacillus thuringiensis and Steinernema carpocapsae. Sci Rep 2021; 11:8149. [PMID: 33854098 PMCID: PMC8046782 DOI: 10.1038/s41598-021-87469-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/30/2021] [Indexed: 02/06/2023] Open
Abstract
Non-native pests are often responsible for serious crop damage. Since Drosophila suzukii has invaded North America and Europe, the global production of soft, thin-skinned fruits has suffered severe losses. The control of this dipteran by pesticides, although commonly used, is not recommended because of the negative impact on the environment and human health. A possible alternative is the use of bio-insecticides, including Bacillus thuringiensis and entomopathogenic nematodes, such as Steinernema carpocapsae. These biological control agents have a fair effectiveness when used individually on D. suzukii, but both have limits related to different environmental, methodological, and physiological factors. In this work, we tested various concentrations of B. thuringiensis and S. carpocapsae to evaluate their efficacy on D. suzukii larvae, when administered individually or in combination by using agar traps. In the combined trials, we added the nematodes after 16 h or concurrently to the bacteria, and assessed larvae lethality from 16 to 48 h. The assays demonstrated a higher efficacy of the combined administration, both time-shifted and concurrent; the obtained data also showed a relevant decrease of the time needed to kill the larvae. Particularly, the maximum mortality rate, corresponding to 79% already at 16 h, was observed with the highest concentrations (0.564 µg/mL of B. thuringiensis and 8 × 102 IJs of S. carpocapsae) in the concurrent trials. This study, conducted by laboratory tests under controlled conditions, is a good starting point to develop a further application step through field studies for the control of D. suzukii.
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Nawrot-Esposito MP, Babin A, Pasco M, Poirié M, Gatti JL, Gallet A. Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae. INSECTS 2020; 11:E697. [PMID: 33066180 PMCID: PMC7601982 DOI: 10.3390/insects11100697] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022]
Abstract
Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the bestselling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt subsp. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is much evidence of the lack of acute lethality of Btk products for non-target animals, only scarce data are available on their potential non-lethal developmental adverse effects. Using a concentration that could be reached in the field upon sprayings, we show that Btk products impair growth and developmental time of the non-target dipteran Drosophila melanogaster. We demonstrate that these effects are mediated by the synergy between Btk bacteria and Btk insecticidal toxins. We further show that Btk bioinsecticides trigger intestinal cell death and alter protein digestion without modifying the food intake and feeding behavior of the larvae. Interestingly, these harmful effects can be mitigated by a protein-rich diet or by adding the probiotic bacterium Lactobacillus plantarum into the food. Finally, we unravel two new cellular mechanisms allowing the larval midgut to maintain its integrity upon Btk aggression: First the flattening of surviving enterocytes and second, the generation of new immature cells arising from the adult midgut precursor cells. Together, these mechanisms participate to quickly fill in the holes left by the dying enterocytes.
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Affiliation(s)
| | | | | | | | | | - Armel Gallet
- Université Côte d’Azur, CNRS, INRAE, ISA, UMR CNRS 7254/INRAE 1355/UCA, 400 route des Chappes, BP 167, 06903 Sophia Antipolis CEDEX, France; (M.-P.N.-E.); (A.B.); (M.P.); (M.P.); (J.-L.G.)
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