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Guimarães B, Römbke J, Amorim MJB. On the importance of longer-term exposure to stressors - A critical review and proposal for multigenerational testing in standard soil invertebrates. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 854:158680. [PMID: 36108845 DOI: 10.1016/j.scitotenv.2022.158680] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 06/15/2023]
Abstract
Standard laboratory tests to describe the impact of stressors (most notably: chemicals) on organisms offer a good compromise between feasibility and outcome, i.e., they should be reproducible and provide robust results. However, these tests may underestimate the potential effects of prolonged exposures, particularly for persistent contaminants. Within the last years, we have observed an increase in studies aiming to target prolonged exposure, e.g., via an extended test duration or by multigenerational (MG) exposure. Seemingly, both reduced and increased impacts have been observed in these studies, but it is also clear that no unique test setup was used, and test designs vary widely among studies. To better describe long term effects, MG is a highly relevant aspect which deserves more consideration at various testing and assessment levels. Therefore, we conducted a literature review focusing on available studies performed with soil invertebrates, exposed to stressors for periods longer than in standard laboratory tests, i.e., full life cycle tests, as well as extensions to standard and MG tests. So far, it has been recommended that such studies should cover more than one generation, but this statement is probably too vague. In this contribution, we summarize and critically discuss the information provided in the literature, and we provide suggestions for future research. The currently available test results from long-term studies have produced clear evidence to recommend the implementation of long-term tests in existing regulatory testing requirements (e.g., for pesticides), in particular for persistent substances and also for delayed effects. Consequently, we recommend the inclusion of such longer exposure test designs (e.g., as annexes) in current OECD and ISO guidelines. However, when doing so, the long-term test designs proposed so far have to be critically adapted for a selected set of representative soil invertebrate test species.
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Affiliation(s)
- B Guimarães
- University of Aveiro, Department of Biology & CESAM, 3810-193 Aveiro, Portugal
| | - J Römbke
- ECT Oekotoxikologie GmbH, Boettgerstr. 2-14, D-65439 Flörsheim, Germany
| | - M J B Amorim
- University of Aveiro, Department of Biology & CESAM, 3810-193 Aveiro, Portugal.
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Luan YX, Cui Y, Chen WJ, Jin JF, Liu AM, Huang CW, Potapov M, Bu Y, Zhan S, Zhang F, Li S. High-quality genomes reveal significant genetic divergence and cryptic speciation in the model organism Folsomia candida (Collembola). Mol Ecol Resour 2022; 23:273-293. [PMID: 35962787 PMCID: PMC10087712 DOI: 10.1111/1755-0998.13699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 12/01/2022]
Abstract
The collembolan Folsomia candida Willem, 1902, is widely distributed throughout the world and has been frequently used as a test organism in soil ecology and ecotoxicology studies. However, it is questioned as an ideal "standard" because of differences in reproductive modes and cryptic genetic diversity between strains from various geographical origins. In this study, we obtained two high-quality chromosome-level genomes of F. candida, for a parthenogenetic strain (named as FCDK, 219.08 Mb, 25,139 protein-coding genes) and a sexual strain (named as FCSH, 153.09 Mb, 21,609 protein-coding genes), reannotated the genome of the parthenogenetic strain reported by Faddeeva-Vakhrusheva et al. in 2017 (named as FCBL, 221.7 Mb, 25,980 protein-coding genes), and conducted comparative genomic analyses of three strains. High genome similarities between FCDK and FCBL on synteny, genome architecture, mitochondrial and nuclear gene sequences support they are conspecific. The seven chromosomes of FCDK are each 25-54% larger than the corresponding chromosomes of FCSH, showing obvious repetitive element expansions and large-scale inversions and translocations but no whole-genome duplication. The strain-specific genes, expanded gene families and genes in nonsyntenic chromosomal regions identified in FCDK are highly related to the broader environmental adaptation of parthenogenetic strains. In addition, FCDK has fewer strain-specific microRNAs than FCSH, and their mitochondrial and nuclear genes have diverged greatly. In conclusion, FCDK/FCBL and FCSH have accumulated independent genetic changes and evolved into distinct species since 10 Mya. Our work provides important genomic resources for studying the mechanisms of rapidly cryptic speciation and soil arthropod adaptation to soil ecosystems.
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Affiliation(s)
- Yun-Xia Luan
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Yingying Cui
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China
| | | | - Jian-Feng Jin
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Ai-Min Liu
- Department of Pomology, College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Cheng-Wang Huang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | | | - Yun Bu
- Natural History Research Center, Shanghai Natural History Museum, Shanghai Science & Technology Museum, Shanghai, China
| | - Shuai Zhan
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Feng Zhang
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Sheng Li
- Guangdong Provincial Key Laboratory of Insect Development Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China.,Guangmeiyuan R&D Center, Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, South China Normal University, Meizhou, China
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