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Witek W, Sliwiak J, Rawski M, Ruszkowski M. Targeting imidazole-glycerol phosphate dehydratase in plants: novel approach for structural and functional studies, and inhibitor blueprinting. FRONTIERS IN PLANT SCIENCE 2024; 15:1343980. [PMID: 38559763 PMCID: PMC10978614 DOI: 10.3389/fpls.2024.1343980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 03/04/2024] [Indexed: 04/04/2024]
Abstract
The histidine biosynthetic pathway (HBP) is targeted for herbicide design with preliminary success only regarding imidazole-glycerol phosphate dehydratase (IGPD, EC 4.2.1.19), or HISN5, as referred to in plants. HISN5 catalyzes the sixth step of the HBP, in which imidazole-glycerol phosphate (IGP) is dehydrated to imidazole-acetol phosphate. In this work, we present high-resolution cryoEM and crystal structures of Medicago truncatula HISN5 (MtHISN5) in complexes with an inactive IGP diastereoisomer and with various other ligands. MtHISN5 can serve as a new model for plant HISN5 structural studies, as it enables resolving protein-ligand interactions at high (2.2 Å) resolution using cryoEM. We identified ligand-binding hotspots and characterized the features of plant HISN5 enzymes in the context of the HISN5-targeted inhibitor design. Virtual screening performed against millions of small molecules not only revealed candidate molecules but also identified linkers for fragments that were experimentally confirmed to bind. Based on experimental and computational approaches, this study provides guidelines for designing symmetric HISN5 inhibitors that can reach two neighboring active sites. Finally, we conducted analyses of sequence similarity networks revealing that plant HISN5 enzymes derive from cyanobacteria. We also adopted a new approach to measure MtHISN5 enzymatic activity using isothermal titration calorimetry and enzymatically synthesized IGP.
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Affiliation(s)
- Wojciech Witek
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Joanna Sliwiak
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Michal Rawski
- Cryo-EM Facility, SOLARIS National Synchrotron Radiation Centre, Krakow, Poland
| | - Milosz Ruszkowski
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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2
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Nouvian M, Foster JJ, Weidenmüller A. Glyphosate impairs aversive learning in bumblebees. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165527. [PMID: 37451452 DOI: 10.1016/j.scitotenv.2023.165527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 07/06/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
Agrochemicals represent prominent anthropogenic stressors contributing to the ongoing global insect decline. While their impact is generally assessed in terms of mortality rates, non-lethal effects on fitness are equally important to insect conservation. Glyphosate, a commonly used herbicide, is toxic to many animal species, and thought to impact a range of physiological functions. In this study, we investigate the impact of long-term exposure to glyphosate on locomotion, phototaxis and learning abilities in bumblebees, using a fully automated high-throughput assay. We find that glyphosate exposure had a very slight and transient impact on locomotion, while leaving the phototactic drive unaffected. Glyphosate exposure also reduced attraction towards UV light when blue was given as an alternative and, most strikingly, impaired learning of aversive stimuli. Thus, glyphosate had specific actions on sensory and cognitive processes. These non-lethal perceptual and cognitive impairments likely represent a significant obstacle to foraging and predator avoidance for wild bumblebees exposed to glyphosate. Similar effects in other species could contribute to a widespread reduction in foraging efficiency across ecosystems, driven by the large-scale application of this herbicide. The high-throughput paradigm presented in this study can be adapted to investigate sublethal effects of other agrochemicals on bumblebees or other important pollinator species, opening up a critical new avenue for the study of anthropogenic stressors.
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Affiliation(s)
- Morgane Nouvian
- Department of Biology, University of Konstanz, Konstanz, Germany; Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany; Zukunftskolleg, University of Konstanz, Konstanz, Germany.
| | - James J Foster
- Department of Biology, University of Konstanz, Konstanz, Germany; Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
| | - Anja Weidenmüller
- Department of Biology, University of Konstanz, Konstanz, Germany; Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany
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3
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Araújo RDS, Viana TA, Botina LL, Bastos DSS, da Silva Alves BC, Machado-Neves M, Bernardes RC, Martins GF. Investigating the effects of mesotrione/atrazine-based herbicide on honey bee foragers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165526. [PMID: 37451454 DOI: 10.1016/j.scitotenv.2023.165526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/05/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
A mixture of the herbicides mesotrione and atrazine (Calaris®) is a widely used herbicide in agriculture in several countries. However, the possible toxicological effects of this formulation on non-target organisms require investigation. In this study, the effects of acute oral exposure to Calaris® were evaluated in Apis mellifera foragers. The effect of seven different concentrations of Calaris® on survival and sucrose consumption was studied, while the recommended concentration for field use (FC) and its 10× dilution (0.1 FC) were used to assess overall locomotor activity, respiratory rate, flight, midgut morphology, oxidative and nitrosative stresses, and hemocyte counting. The exposure to FC or 0.1 FC decreased locomotor activity and induced damage to the midgut epithelium. Additionally, the two tested concentrations reduced superoxide dismutase activity, nitric oxide levels, and total hemocyte count. FC also increased malondialdehyde content and 0.1 FC increased respiratory rate and decreased the proportion of prohemocytes. Overall, our findings evidenced significant harmful effects on A. mellifera foragers resulting from the ingestion of the Calaris® herbicide.
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Affiliation(s)
- Renan Dos Santos Araújo
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso, 78698-000 Pontal do Araguaia, MT, Brazil.
| | - Thaís Andrade Viana
- Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
| | - Lorena Lisbetd Botina
- Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
| | | | | | - Mariana Machado-Neves
- Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil.
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4
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Ferrante M, Rapisarda P, Grasso A, Favara C, Oliveri Conti G. Glyphosate and environmental toxicity with "One Health" approach, a review. ENVIRONMENTAL RESEARCH 2023; 235:116678. [PMID: 37459948 DOI: 10.1016/j.envres.2023.116678] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/26/2023]
Abstract
The herbicide Glyphosate (GLY), or N-(phosphonomethyl) glycine was synthesized in 1950 and applied to control weeds in agricultural production. For a long time, it was believed that it was an inert compound, but many studies have instead demonstrated over the years the dangers of GLY to the ecosystem and human health. Among the best-known effects, it is known that GLY interferes with the metabolic pathways of plants and the main groups of microorganisms, negatively influencing their growth. GLY interferes with the metabolic pathways of plants and major groups of microorganisms negatively affecting their growth. The extensive GLY application on fields results in a "slow death" of plants through the minor resistance to root pathogens and in increasing pollution of freshwaters and soils. Unfortunately, however, unlike the old beliefs, GLY can reach non-target destinations, in this regard, ecological studies and environmental epidemiology are of significant interest. In this review, we focus on the effects of acute and chronic exposure to GLY on the health of plants, animals, and humans from a One Health perspective. GLY has been linked to neurological and endocrine issues in both humans and animals, and behavioral modification on specific bioindicators, but the knowledge about the ratio cause-and-effect still needs to be better understood and elucidated. Environmental GLY residues analysis and policy acts will both require new criteria to protect environmental and human health.
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Affiliation(s)
- Margherita Ferrante
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical, Surgical and Advanced Technology "G.F. Ingrassia", University of Catania, Catania, Italy; International Society of Doctors for Environments - ISDE, Catania Section, Italy
| | - Paola Rapisarda
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical, Surgical and Advanced Technology "G.F. Ingrassia", University of Catania, Catania, Italy; International Society of Doctors for Environments - ISDE, Catania Section, Italy
| | - Alfina Grasso
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical, Surgical and Advanced Technology "G.F. Ingrassia", University of Catania, Catania, Italy; International Society of Doctors for Environments - ISDE, Catania Section, Italy
| | - Claudia Favara
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical, Surgical and Advanced Technology "G.F. Ingrassia", University of Catania, Catania, Italy; International Society of Doctors for Environments - ISDE, Catania Section, Italy; Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy
| | - Gea Oliveri Conti
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical, Surgical and Advanced Technology "G.F. Ingrassia", University of Catania, Catania, Italy; International Society of Doctors for Environments - ISDE, Catania Section, Italy.
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5
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Urueña Á, Blasco-Lavilla N, De la Rúa P. Sulfoxaflor effects depend on the interaction with other pesticides and Nosema ceranae infection in the honey bee (Apis mellifera). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 264:115427. [PMID: 37666201 DOI: 10.1016/j.ecoenv.2023.115427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/26/2023] [Accepted: 08/30/2023] [Indexed: 09/06/2023]
Abstract
Honey bees health is compromised by many factors such as the use of agrochemicals in agriculture and the various diseases that can affect them. Multiple studies have shown that these factors can interact, producing a synergistic effect that can compromise the viability of honey bees. This study analyses the interactions between different pesticides and the microsporidium Nosema ceranae and their effect on immune and detoxification gene expression, sugar consumption and mortality in the Iberian western honey bee (Apis mellifera iberiensis). For this purpose, workers were infected with N. ceranae and subjected to a sugar-water diet with field concentrations of the pesticides sulfoxaflor, azoxystrobin and glyphosate. Increased sugar intake and altered immune and cytochrome P450 gene expression were observed in workers exposed to sulfoxaflor and infected with N. ceranae. None of the pesticides affected Nosema spore production in honey bee gut. Of the three pesticides tested (alone or in combination) only sulfoxaflor increased mortality in honey bees. Taken together, our results suggest that the effects of sulfoxaflor were attenuated in contact with other pesticides, and that Nosema infection leads to increase sugar intake in sulfoxaflor-exposed bees. Overall, this underlines the importance of studying the interaction between different stressors to understand their overall impact not only on honey bee but also on wild bees health.
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Affiliation(s)
- Álvaro Urueña
- Department of Zoology and Physical Anthropology, Faculty of Veterinary, University of Murcia, 30100 Murcia, Spain
| | - Nuria Blasco-Lavilla
- Department of Zoology and Physical Anthropology, Faculty of Veterinary, University of Murcia, 30100 Murcia, Spain
| | - Pilar De la Rúa
- Department of Zoology and Physical Anthropology, Faculty of Veterinary, University of Murcia, 30100 Murcia, Spain.
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Pons DG, Herrera C, Torrens-Mas M, Leza M, Sastre-Serra J. Sublethal doses of glyphosate modulates mitochondria and oxidative stress in honeybees by direct feeding. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2023; 114:e22028. [PMID: 37259187 DOI: 10.1002/arch.22028] [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: 02/14/2023] [Revised: 05/18/2023] [Accepted: 05/22/2023] [Indexed: 06/02/2023]
Abstract
Honeybees are essential for the ecosystem maintenance and for plant production in agriculture. Glyphosate is a broad-spectrum systemic herbicide widely used in crops to control weeds and could affect honeybees' health in sublethal doses. Our aim was to study how sublethal doses of glyphosate affects to oxidative stress and mitochondrial homeostasis in honeybees. We exposed honeybees to glyphosate at 5 and 10 mg·l-1 for 2 and 10 h for the gene expression analysis by reverse transcription polymerase chain reaction and for 48 and 72 h for the antioxidant enzymes activity and lipid peroxidation determination. We observed a general increase in antioxidant- and mitochondrial-related genes expression in honeybees after 2 h of exposition to glyphosate, as well as a rise in catalase and superoxide dismutase enzymatic activity after 48 h and an increment in lipid peroxidation adducts generation after 72 h. These results suggest a direct effect of glyphosate on honeybees' health, with an insufficient response of the antioxidant system to the generated oxidative stress, resulting in an increase in lipid peroxidation and, therefore, oxidative damage. Altogether, results obtained in this work demonstrate that sublethal treatments of glyphosate could directly affect honeybee individuals under laboratory conditions. Therefore, it is necessary to investigate alternatives to glyphosate to determine if they are less harmful to non-target organisms.
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Affiliation(s)
- Daniel Gabriel Pons
- Grupo Multidisciplinar de Oncología Traslacional, Institut Universitari d´Investigació en Ciències de la Salut (IUNICS), University of the Balearic Islands, Palma de Mallorca, Illes Balears, Spain
- Instituto de Investigación Sanitaria de las Islas Baleares (IdISBa), Hospital Universitario Son Espases, edificio S, Palma de Mallorca, Illes Balears, Spain
| | - Cayetano Herrera
- Department of Biology (Zoology), University of the Balearic Islands, Palma, Balearic Islands, Spain
| | - Margalida Torrens-Mas
- Grupo Multidisciplinar de Oncología Traslacional, Institut Universitari d´Investigació en Ciències de la Salut (IUNICS), University of the Balearic Islands, Palma de Mallorca, Illes Balears, Spain
- Instituto de Investigación Sanitaria de las Islas Baleares (IdISBa), Hospital Universitario Son Espases, edificio S, Palma de Mallorca, Illes Balears, Spain
- Translational Research In Aging and Longevity (TRIAL) Health Research Institute of the Balearic Islands (IdISBa), Palma de Mallorca, Spain
| | - Mar Leza
- Department of Biology (Zoology), University of the Balearic Islands, Palma, Balearic Islands, Spain
| | - Jorge Sastre-Serra
- Grupo Multidisciplinar de Oncología Traslacional, Institut Universitari d´Investigació en Ciències de la Salut (IUNICS), University of the Balearic Islands, Palma de Mallorca, Illes Balears, Spain
- Instituto de Investigación Sanitaria de las Islas Baleares (IdISBa), Hospital Universitario Son Espases, edificio S, Palma de Mallorca, Illes Balears, Spain
- Ciber Fisiopatología Obesidad y Nutrición (CB06/03) Instituto Salud Carlos III, Madrid, Spain
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Ferreira LMN, Hrncir M, de Almeida DV, Bernardes RC, Lima MAP. Effects of acephate and glyphosate-based agrochemicals on the survival and flight of Plebeia lucii Moure, 2004 (Apidae: Meliponini). ECOTOXICOLOGY (LONDON, ENGLAND) 2023; 32:926-936. [PMID: 37728837 DOI: 10.1007/s10646-023-02698-9] [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] [Accepted: 09/12/2023] [Indexed: 09/21/2023]
Abstract
The conservation of terrestrial ecosystems depends largely on the preservation of pollinators, mainly bees. Stingless bees are among the main pollinators of native plants and crops in tropical regions, where they can be exposed to agrochemicals while foraging on contaminated flowers. In the present study, we investigated the effects on stingless bees of both a commonly used insecticide and herbicide in Brazil. Plebeia lucii Moure, 2004 (Apidae: Meliponini) foragers were orally chronically exposed to food contaminated with different concentrations of commercial formulations of the insecticide acephate or the herbicide glyphosate. Bee mortality increased with increasing agrochemical concentrations. Depending on its concentration, the acephate-based formulation reduced the lifespan and impaired the flight ability of bees. The glyphosate-based formulation was toxic only under unrealistic concentrations. Our results demonstrate that realistic concentrations of acephate-based insecticides harm the survival and alter the mobility of stingless bees. The ingestion of glyphosate-based herbicides was safe for forager bees under realistic concentrations.
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Affiliation(s)
- Lívia Maria Negrini Ferreira
- Universidade Federal de Viçosa, Departamento de Biologia Geral, Programa de Pós-Graduação em Ecologia, Viçosa, MG, Brazil.
- Universidade Federal de Viçosa, Departamento de Entomologia, Viçosa, MG, Brazil.
| | - Michael Hrncir
- Universidade de São Paulo, Departamento de Fisiologia, São Paulo, SP, Brazil
| | - Danilo Vieira de Almeida
- Universidade Federal de Viçosa, Departamento de Agronomia, Curso de Graduação em Agronomia, Viçosa, MG, Brazil
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8
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Flach H, Dietmann P, Liess M, Kühl M, Kühl SJ. Glyphosate without Co-formulants affects embryonic development of the south african clawed frog Xenopus laevis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 260:115080. [PMID: 37262967 DOI: 10.1016/j.ecoenv.2023.115080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/16/2023] [Accepted: 05/25/2023] [Indexed: 06/03/2023]
Abstract
BACKGROUND Glyphosate (GLY) is the most widely used herbicide in the world. Due to its mode of action as an inhibitor of the 5-enolpyruvylshikimate-3-phosphate synthase, an important step in the shikimate pathway, specifically in plants, GLY is considered to be of low toxicity to non-target organisms. However, various studies have shown the negative effects of GLY on the mortality and development of different non-target organisms, including insects, rodents, fish and amphibians. To better understand the various effects of GLY in more detail, we studied the effects of GLY without co-formulants during the embryogenesis of the aquatic model organism Xenopus laevis. RESULTS A treatment with GLY affected various morphological endpoints in X. laevis tadpoles (body length, head width and area, eye area). Additionally, GLY interfered with the mobility as well as the neural and cardiac development of the embryos at stage 44/45. We were able to detect detailed structural changes in the cranial nerves and the heart and gained insights into the negative effects of GLY on cardiomyocyte differentiation. CONCLUSION The application of GLY without co-formulants resulted in negative effects on several endpoints in the early embryonic development of X. laevis at concentrations that are environmentally relevant and concentrations that reflect the worst-case scenarios. This indicates that GLY could have a strong negative impact on the survival and lives of amphibians in natural waters. As a result, future GLY approvals should consider its impact on the environment.
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Affiliation(s)
- Hannah Flach
- Institute of Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Petra Dietmann
- Institute of Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Matthias Liess
- Department System-Ecotoxicology, Helmholtz Centre for Environmental Research, UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Michael Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Susanne J Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
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9
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Motta EVS, Moran NA. The effects of glyphosate, pure or in herbicide formulation, on bumble bees and their gut microbial communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 872:162102. [PMID: 36764553 PMCID: PMC11050743 DOI: 10.1016/j.scitotenv.2023.162102] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/29/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
The widespread use of glyphosate-based formulations to eliminate unwanted vegetation has increased concerns regarding their effects on non-target organisms, such as honey bees and their gut microbial communities. These effects have been associated with both glyphosate and co-formulants, but it is still unknown whether they translate to other bee species. In this study, we tested whether glyphosate, pure or in herbicide formulation, can affect the gut microbiota and survival rates of the eastern bumble bee, Bombus impatiens. We performed mark-recapture experiments with bumble bee workers from four different commercial colonies, which were exposed to field relevant concentrations of glyphosate or a glyphosate-based formulation (0.01 mM to 1 mM). After a 5-day period of exposure, we returned the bees to their original colonies, and they were sampled at days 0, 3 and 7 post-exposure to investigate changes in microbial community and microbiota resilience by 16S rRNA amplicon sequencing and quantitative PCR. We found that exposure to glyphosate, pure or in herbicide formulation, reduced the relative abundance of a beneficial bee gut bacterium, Snodgrassella, in bees from two of four colonies when compared to control bees at day 0 post-exposure, but this reduction became non-significant at days 3 and 7 post-exposure, suggesting microbiota resilience. We did not find significant changes in total bacteria between control and exposed bees. Moreover, we observed an overall trend in decreased survival rates in bumble bees exposed to 1 mM herbicide formulation during the 7-day post-exposure period, suggesting a potential negative effect of this formulation on bumble bees.
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Affiliation(s)
- Erick V S Motta
- Department of Integrative Biology, University of Texas at Austin, TX, USA.
| | - Nancy A Moran
- Department of Integrative Biology, University of Texas at Austin, TX, USA.
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Rutkiewicz M, Nogues I, Witek W, Angelaccio S, Contestabile R, Ruszkowski M. Insights into the substrate specificity, structure, and dynamics of plant histidinol-phosphate aminotransferase (HISN6). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 196:759-773. [PMID: 36842242 DOI: 10.1016/j.plaphy.2023.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/01/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
Histidinol-phosphate aminotransferase is the sixth protein (hence HISN6) in the histidine biosynthetic pathway in plants. HISN6 is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the reversible conversion of imidazole acetol phosphate into L-histidinol phosphate (HOLP). Here, we show that plant HISN6 enzymes are closely related to the orthologs from Chloroflexota. The studied example, HISN6 from Medicago truncatula (MtHISN6), exhibits a surprisingly high affinity for HOLP, which is much higher than reported for bacterial homologs. Moreover, unlike the latter, MtHISN6 does not transaminate phenylalanine. High-resolution crystal structures of MtHISN6 in the open and closed states, as well as the complex with HOLP and the apo structure without PLP, bring new insights into the enzyme dynamics, pointing at a particular role of a string-like fragment that oscillates near the active site and participates in the HOLP binding. When MtHISN6 is compared to bacterial orthologs with known structures, significant differences arise in or near the string region. The high affinity of MtHISN6 appears linked to the particularly tight active site cavity. Finally, a virtual screening against a library of over 1.3 mln compounds revealed three sites in the MtHISN6 structure with the potential to bind small molecules. Such compounds could be developed into herbicides inhibiting plant HISN6 enzymes absent in animals, which makes them a potential target for weed control agents.
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Affiliation(s)
- Maria Rutkiewicz
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Isabel Nogues
- Research Institute on Terrestrial Ecosystems, National Research Council, Monterotondo Scalo, Rome, Italy
| | - Wojciech Witek
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Sebastiana Angelaccio
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Roberto Contestabile
- Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Milosz Ruszkowski
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland.
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11
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da Silva PC, Gonçalves B, Franceschinelli E, Brito P. Glyphosate-Based Herbicide Causes Cellular Alterations to Gut Epithelium of the Neotropical Stingless Bee Melipona quadrifasciata quadrifasciata (Hymenoptera: Meliponini). NEOTROPICAL ENTOMOLOGY 2022; 51:860-868. [PMID: 36378479 DOI: 10.1007/s13744-022-01001-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Glyphosate-based herbicides (GBH) are the best-selling pesticides in Brazil, with hundreds of thousands of tons sold per year. There is no study investigating morphological alterations caused by GBH on the epithelium of the gut in bees. Here, we aimed to demonstrate effects of chronic ingestion of GBH in the midgut digestive cells of the Brazilian stingless bee Melipona quadrifasciata quadrifasciata Lepeletier 1836. We kept forager workers of M. quadrifasciata in laboratory conditions and fed on food contaminated with three different concentrations of GBH for 10 days, after which the midgut digestive cell structure and ultrastructure were analyzed. The presence of GBH in food did not affect food consumption, indicating that M. quadrifasciata bees do not reject food contaminated with GBH. As digestive cells of the midgut release apocrine secretion as a detoxication mechanism, we expected that the ingestion of food contaminated with GBH in the present study affect the height of midgut digestive cells. However, such reduction did not occur, probably because of the low-test concentrations. Although there were differences in digestive cell ultrastructure, ingestion of GBH impaired midgut digestive cell cohesion by disorganizing the smooth septate junctions between cells, which may probably be caused by the adjuvant "polyethoxylated tallow amine" present in the GBH. Previous studies demonstrated that GBH increase bees' sensibility to intestine infections, based on the present results we hypothesized that the loss of cell cohesion in the midgut epithelium favors pathogenic microbial infections and harms food absorption, increasing bees' mortality.
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Affiliation(s)
- Paulo César da Silva
- Programa de Pós-Graduação Em Biodiversidade Animal, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Bruno Gonçalves
- Laboratório de Biotecnologia Ambiental e Ecotoxicologia, Instituto Tropical de Patologia e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Edivani Franceschinelli
- Laboratório de Biologia Reprodutiva de Plantas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Pedro Brito
- Laboratório de Estudos Morfológicos, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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12
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Weidenmüller A, Meltzer A, Neupert S, Schwarz A, Kleineidam C. Glyphosate impairs collective thermoregulation in bumblebees. Science 2022; 376:1122-1126. [PMID: 35653462 DOI: 10.1126/science.abf7482] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Insects are facing a multitude of anthropogenic stressors, and the recent decline in their biodiversity is threatening ecosystems and economies across the globe. We investigated the impact of glyphosate, the most commonly used herbicide worldwide, on bumblebees. Bumblebee colonies maintain their brood at high temperatures via active thermogenesis, a prerequisite for colony growth and reproduction. Using a within-colony comparative approach to examine the effects of long-term glyphosate exposure on both individual and collective thermoregulation, we found that whereas effects are weak at the level of the individual, the collective ability to maintain the necessary high brood temperatures is decreased by more than 25% during periods of resource limitation. For pollinators in our heavily stressed ecosystems, glyphosate exposure carries hidden costs that have so far been largely overlooked.
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Affiliation(s)
- Anja Weidenmüller
- Centre for the Advanced Study of Collective Behavior, Konstanz, Germany
- University of Konstanz, Konstanz, Germany
| | - Andrea Meltzer
- University of Konstanz, Konstanz, Germany
- Max Planck Institute of Animal Behavior, Konstanz, Germany
| | - Stefanie Neupert
- University of Konstanz, Konstanz, Germany
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Alica Schwarz
- Centre for the Advanced Study of Collective Behavior, Konstanz, Germany
- University of Konstanz, Konstanz, Germany
| | - Christoph Kleineidam
- Centre for the Advanced Study of Collective Behavior, Konstanz, Germany
- University of Konstanz, Konstanz, Germany
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13
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Pal E, Almasri H, Paris L, Diogon M, Pioz M, Cousin M, Sené D, Tchamitchian S, Tavares DA, Delbac F, Blot N, Brunet JL, Belzunces LP. Toxicity of the Pesticides Imidacloprid, Difenoconazole and Glyphosate Alone and in Binary and Ternary Mixtures to Winter Honey Bees: Effects on Survival and Antioxidative Defenses. TOXICS 2022; 10:toxics10030104. [PMID: 35324729 PMCID: PMC8954695 DOI: 10.3390/toxics10030104] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/21/2022] [Indexed: 02/05/2023]
Abstract
To explain losses of bees that could occur after the winter season, we studied the effects of the insecticide imidacloprid, the herbicide glyphosate and the fungicide difenoconazole, alone and in binary and ternary mixtures, on winter honey bees orally exposed to food containing these pesticides at concentrations of 0, 0.01, 0.1, 1 and 10 µg/L. Attention was focused on bee survival, food consumption and oxidative stress. The effects on oxidative stress were assessed by determining the activity of enzymes involved in antioxidant defenses (superoxide dismutase, catalase, glutathione-S-transferase, glutathione reductase, glutathione peroxidase and glucose-6-phosphate dehydrogenase) in the head, abdomen and midgut; oxidative damage reflected by both lipid peroxidation and protein carbonylation was also evaluated. In general, no significant effect on food consumption was observed. Pesticide mixtures were more toxic than individual substances, and the highest mortalities were induced at intermediate doses of 0.1 and 1 µg/L. The toxicity was not always linked to the exposure level and the number of substances in the mixtures. Mixtures did not systematically induce synergistic effects, as antagonism, subadditivity and additivity were also observed. The tested pesticides, alone and in mixtures, triggered important, systemic oxidative stress that could largely explain pesticide toxicity to honey bees.
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Affiliation(s)
- Elisa Pal
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Hanine Almasri
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Laurianne Paris
- CNRS, Laboratoire Microorganismes, Génome et Environnement, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France; (L.P.); (M.D.); (F.D.); (N.B.)
| | - Marie Diogon
- CNRS, Laboratoire Microorganismes, Génome et Environnement, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France; (L.P.); (M.D.); (F.D.); (N.B.)
| | - Maryline Pioz
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Marianne Cousin
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Déborah Sené
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Sylvie Tchamitchian
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Daiana Antonia Tavares
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Frédéric Delbac
- CNRS, Laboratoire Microorganismes, Génome et Environnement, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France; (L.P.); (M.D.); (F.D.); (N.B.)
| | - Nicolas Blot
- CNRS, Laboratoire Microorganismes, Génome et Environnement, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France; (L.P.); (M.D.); (F.D.); (N.B.)
| | - Jean-Luc Brunet
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
| | - Luc P. Belzunces
- INRAE, UR 406 A&E, Laboratoire de Toxicologie Environnementale, F-84000 Avignon, France; (E.P.); (H.A.); (M.P.); (M.C.); (D.S.); (S.T.); (D.A.T.); (J.-L.B.)
- Correspondence: ; Tel.: +33-(0)43272-2604
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14
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Bernardes RC, Botina LL, da Silva FP, Fernandes KM, Lima MAP, Martins GF. Toxicological assessment of agrochemicals on bees using machine learning tools. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127344. [PMID: 34607030 DOI: 10.1016/j.jhazmat.2021.127344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/22/2021] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Machine learning (ML) is a branch of artificial intelligence (AI) that enables the analysis of complex multivariate data. ML has significant potential in risk assessments of non-target insects for modeling the multiple factors affecting insect health, including the adverse effects of agrochemicals. Here, the potential of ML for risk assessments of glyphosate (herbicide; formulation) and imidacloprid (insecticide, neonicotinoid; formulation) on the stingless bee Melipona quadrifasciata was explored. The collective behavior of forager bees was analyzed after in vitro exposure to agrochemicals. ML algorithms were applied to identify the agrochemicals that the bees have been exposed to based on multivariate behavioral features. Changes in the in situ detection of different proteins in the midgut were also studied. Imidacloprid exposure leads to the greatest changes in behavior. The ML algorithms achieved a higher accuracy (up to 91%) in identifying agrochemical contamination. The two agrochemicals altered the detection of cells positive for different proteins, which can be detrimental to midgut physiology. This study provides a holistic assessment of the sublethal effects of glyphosate and imidacloprid on a key pollinator. The procedures used here can be applied in future studies to monitor and predict multiple environmental factors affecting insect health in the field.
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Affiliation(s)
| | - Lorena Lisbetd Botina
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | | | - Kenner Morais Fernandes
- Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
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15
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Tan S, Li G, Liu Z, Wang H, Guo X, Xu B. Effects of glyphosate exposure on honeybees. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2022; 90:103792. [PMID: 34971799 DOI: 10.1016/j.etap.2021.103792] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/24/2021] [Accepted: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Honeybees show an important pollination ability and play vital roles in improving crop yields and increasing plant genetic diversity, thereby generating tremendous economic benefits for humans. However, honeybee survival is affected by a number of biological and abiotic stresses, including the effects of fungi, bacteria, viruses, parasites, and especially agrochemicals. Glyphosate, a broad-spectrum herbicide that is primarily used for weed control in agriculture, has been reported to have lethal and sublethal effects on honeybees. Here, we summarize recent advances in research on the effects of glyphosate on honeybees, including effects on their behaviors, growth and development, metabolic processes, and immune defense, providing a detailed reference for studying the mechanism of action of pesticides. Furthermore, we provide possible directions for future research on glyphosate toxicity to honeybees.
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Affiliation(s)
- Shuai Tan
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Guilin Li
- College of Life Sciences, Qufu Normal University, Qufu 273165, PR China
| | - Zhenguo Liu
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Hongfang Wang
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong 271018, PR China
| | - Xingqi Guo
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong 271018, PR China.
| | - Baohua Xu
- College of Animal Science and Technology, Shandong Agricultural University, Taian, Shandong 271018, PR China.
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16
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Ye Z, Wu F, Hennessy DA. Environmental and economic concerns surrounding restrictions on glyphosate use in corn. Proc Natl Acad Sci U S A 2021; 118:e2017470118. [PMID: 33903235 PMCID: PMC8106354 DOI: 10.1073/pnas.2017470118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Since the commercialization of transgenic glyphosate-tolerant (GT) crops in the mid-1990s, glyphosate has become the dominant herbicide to control weeds in corn, soybean, and other crops in the United States and elsewhere. However, recent public concerns over its potential carcinogenicity in humans have generated calls for glyphosate-restricting policies. Should a policy to restrict glyphosate use, such as a glyphosate tax, be implemented? The decision involves two types of tradeoffs: human health and environmental (HH-E) impacts versus market economic impacts, and the use of glyphosate versus alternative herbicides, where the alternatives potentially have more serious adverse HH-E effects. Accounting for farmers' weed management choices, we provide empirical evaluation of the HH-E welfare and market economic welfare effects of a glyphosate use restriction policy on US corn production. Under a glyphosate tax, farmers would substitute glyphosate for a combination of other herbicides. Should a 10% glyphosate tax be imposed, then the most conservative welfare estimate is a net HH-E welfare gain with a monetized value of US$6 million per annum but also a net market economic loss of US$98 million per annum in the United States, which translates into a net loss in social welfare. This result of overall welfare loss is robust to a wide range of tax rates considered, from 10 to 50%, and to multiple scenarios of glyphosate's HH-E effects, which are the primary sources of uncertainties about glyphosate's effects.
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Affiliation(s)
- Ziwei Ye
- Department of Agricultural, Food, and Resource Economics, Michigan State University, East Lansing, MI 48824
| | - Felicia Wu
- Department of Agricultural, Food, and Resource Economics, Michigan State University, East Lansing, MI 48824
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824
| | - David A Hennessy
- Department of Agricultural, Food, and Resource Economics, Michigan State University, East Lansing, MI 48824;
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17
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Battisti L, Potrich M, Sampaio AR, de Castilhos Ghisi N, Costa-Maia FM, Abati R, Dos Reis Martinez CB, Sofia SH. Is glyphosate toxic to bees? A meta-analytical review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 767:145397. [PMID: 33636765 DOI: 10.1016/j.scitotenv.2021.145397] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/14/2020] [Accepted: 01/20/2021] [Indexed: 05/26/2023]
Abstract
Glyphosate (GLY) is an herbicide widely used in agriculture. First considered as non-toxic or slightly toxic to bees, GLY and its different formulations have shown, more recently, to affect negatively the survival, development and behavior of these insects, even when used in doses and concentrations recommended by the manufacturer. Thus, the results of research on the toxicity of GLY to bees are often conflicting, which makes a meta-analysis interesting for data integration, generating a statistically reliable result. Therefore, this study aimed to evaluate the GLY effects on mortality of bees through a meta-analysis. For this, a search was carried out in the databases Web of Science, CAPES (Coordination for the Improvement of Higher Education Personnel - Brazil), Scopus, and PubMed. Papers that evaluated the effect of GLY on bee mortality published between 1945 and October 2020, were considered. After obtaining the data, R software was used to perform the meta-analytical tests. Sixteen papers on mortality were selected with 34 data sets. Most of the sets demonstrated differences between the control and experimental groups, showing that the treatments with GLY caused higher mortality of bees. The results considering the methodology used (ingestion or contact), the phase of the biological cycle (adults or larvae), and the dose (ecologically relevant dose and recommended by the manufacturer) were different when compared with their respective control groups. Therefore, GLY can be considered toxic to bees. It is important to emphasize that this meta-analysis identified that papers assessing the toxicity of GLY to bees are still scarce, for both lethal and sublethal effects, mainly for stingless and solitary bee species.
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Affiliation(s)
- Lucas Battisti
- Universidade Estadual de Londrina (UEL), Programa de Pós-Graduação em Ciências Biológicas, Rodovia Celso Garcia Cid, PR 445 km 380, Campus Universitário, 86057-970 Londrina, PR, Brazil
| | - Michele Potrich
- Universidade Tecnológica Federal do Paraná, UTFPR, Campus Dois Vizinhos, LABCON, Estrada para Boa Esperança, km 04, Comunidade São Cristóvão, 86660-000 Dois Vizinhos, PR, Brazil.
| | - Amanda Roberta Sampaio
- Universidade Tecnológica Federal do Paraná, UTFPR, Campus Dois Vizinhos, LABCON, Estrada para Boa Esperança, km 04, Comunidade São Cristóvão, 86660-000 Dois Vizinhos, PR, Brazil
| | - Nédia de Castilhos Ghisi
- Universidade Tecnológica Federal do Paraná, Campus Dois Vizinhos, UTFPR, Programa de Pós-Graduação em Biotecnologia, Estrada para Boa Esperança, km 04, Comunidade São Cristóvão, 86660-000 Dois Vizinhos, PR, Brazil
| | - Fabiana Martins Costa-Maia
- Universidade Tecnológica Federal do Paraná, UFTPR, Campus Dois Vizinhos, UNEPE Apicultura, Estrada para Boa Esperança, km 04, Comunidade São Cristóvão, 86660-000 Dois Vizinhos, PR, Brazil
| | - Raiza Abati
- Universidade Tecnológica Federal do Paraná, UTFPR, Campus Dois Vizinhos, LABCON, Estrada para Boa Esperança, km 04, Comunidade São Cristóvão, 86660-000 Dois Vizinhos, PR, Brazil
| | - Claudia Bueno Dos Reis Martinez
- Universidade Estadual de Londrina (UEL), Programa de Pós-Graduação em Ciências Biológicas, Rodovia Celso Garcia Cid, PR 445 km 380, Campus Universitário, 86057-970 Londrina, PR, Brazil
| | - Silvia Helena Sofia
- Universidade Estadual de Londrina (UEL), Programa de Pós-Graduação em Ciências Biológicas, Rodovia Celso Garcia Cid, PR 445 km 380, Campus Universitário, 86057-970 Londrina, PR, Brazil
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18
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Strobl V, Camenzind D, Minnameyer A, Walker S, Eyer M, Neumann P, Straub L. Positive Correlation between Pesticide Consumption and Longevity in Solitary Bees: Are We Overlooking Fitness Trade-Offs? INSECTS 2020; 11:E819. [PMID: 33233695 PMCID: PMC7699727 DOI: 10.3390/insects11110819] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/05/2020] [Accepted: 11/18/2020] [Indexed: 12/14/2022]
Abstract
The ubiquitous use of pesticides is one major driver for the current loss of biodiversity, and the common practice of simultaneously applying multiple agrochemicals may further contribute. Insect toxicology currently has a strong focus on survival to determine the potential hazards of a chemical routinely used in risk evaluations. However, studies revealing no effect on survival or even indicating enhanced survival are likely to be misleading, if potential trade-offs between survival and other physiological factors are overlooked. Here, we used standard laboratory experiments to investigate the sublethal (i.e., food consumption) and lethal (i.e., survival) effects of two common agricultural pesticides (Roundup® and clothianidin) on adult female solitary bees, Osmia bicornis. The data showed no significant effect of the treatment on cumulative survival; however, a significant positive correlation between herbicide and insecticide exposure and age was revealed, i.e., bees exposed to higher dosages lived longer. As no significant differences in daily food consumption were observed across treatment groups, increased food intake can be excluded as a factor leading to the prolonged survival. While this study does not provide data on fitness effects, two previous studies using solitary bees observed significant negative effects of neonicotinoid insecticides on fitness, yet not on survival. Thus, we conjecture that the observed non-significant effects on longevity may result from a trade-off between survival and reproduction. The data suggest that a focus on survival can lead to false-negative results and it appears inevitable to include fitness or at least tokens of fitness at the earliest stage in future risk assessments.
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Affiliation(s)
- Verena Strobl
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland; (D.C.); (A.M.); (S.W.); (P.N.)
| | - Domenic Camenzind
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland; (D.C.); (A.M.); (S.W.); (P.N.)
| | - Angela Minnameyer
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland; (D.C.); (A.M.); (S.W.); (P.N.)
| | - Stephanie Walker
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland; (D.C.); (A.M.); (S.W.); (P.N.)
| | - Michael Eyer
- Laboratory of Soil Biodiversity, University of Neuchâtel, 2000 Neuchâtel, Switzerland;
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland; (D.C.); (A.M.); (S.W.); (P.N.)
| | - Lars Straub
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland; (D.C.); (A.M.); (S.W.); (P.N.)
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19
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Klein BA, Busby MK. Slumber in a cell: honeycomb used by honey bees for food, brood, heating… and sleeping. PeerJ 2020; 8:e9583. [PMID: 32844058 PMCID: PMC7414769 DOI: 10.7717/peerj.9583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/30/2020] [Indexed: 11/30/2022] Open
Abstract
Sleep appears to play an important role in the lives of honey bees, but to understand how and why, it is essential to accurately identify sleep, and to know when and where it occurs. Viewing normally obscured honey bees in their nests would be necessary to calculate the total quantity and quality of sleep and sleep’s relevance to the health and dynamics of a honey bee and its colony. Western honey bees (Apis mellifera) spend much of their time inside cells, and are visible only by the tips of their abdomens when viewed through the walls of an observation hive, or on frames pulled from a typical beehive. Prior studies have suggested that honey bees spend some of their time inside cells resting or sleeping, with ventilatory movements of the abdomen serving as a telltale sign distinguishing sleep from other behaviors. Bouts of abdominal pulses broken by extended pauses (discontinuous ventilation) in an otherwise relatively immobile bee appears to indicate sleep. Can viewing the tips of abdomens consistently and predictably indicate what is happening with the rest of a bee’s body when inserted deep inside a honeycomb cell? To distinguish a sleeping bee from a bee maintaining cells, eating, or heating developing brood, we used a miniature observation hive with slices of honeycomb turned in cross-section, and filmed the exposed cells with an infrared-sensitive video camera and a thermal camera. Thermal imaging helped us identify heating bees, but simply observing ventilatory movements, as well as larger motions of the posterior tip of a bee’s abdomen was sufficient to noninvasively and predictably distinguish heating and sleeping inside comb cells. Neither behavior is associated with large motions of the abdomen, but heating demands continuous (vs. discontinuous) ventilatory pulsing. Among the four behaviors observed inside cells, sleeping constituted 16.9% of observations. Accuracy of identifying sleep when restricted to viewing only the tip of an abdomen was 86.6%, and heating was 73.0%. Monitoring abdominal movements of honey bees offers anyone with a view of honeycomb the ability to more fully monitor when and where behaviors of interest are exhibited in a bustling nest.
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Affiliation(s)
- Barrett A Klein
- Biology Department, University of Wisconsin-La Crosse, La Crosse, WI, USA
| | - M Kathryn Busby
- Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, Tucson, AZ, USA
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