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Porco D, Purnomo CA, Glesener L, Proess R, Lippert S, Jans K, Colling G, Schneider S, Stassen R, Frantz AC. eDNA-based monitoring of Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans with ddPCR in Luxembourg ponds: taking signals below the Limit of Detection (LOD) into account. BMC Ecol Evol 2024; 24:4. [PMID: 38178008 PMCID: PMC10768104 DOI: 10.1186/s12862-023-02189-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 12/09/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are two pathogenic fungi that are a significant threat to amphibian communities worldwide. European populations are strongly impacted and the monitoring of the presence and spread of these pathogens is crucial for efficient decision-making in conservation management. RESULTS Here we proposed an environmental DNA (eDNA) monitoring of these two pathogenic agents through droplet digital PCR (ddPCR) based on water samples from 24 ponds in Luxembourg. In addition, amphibians were swabbed in eight of the targeted ponds in order to compare the two approaches at site-level detection. This study allowed the development of a new method taking below-Limit of Detection (LOD) results into account thanks to the statistical comparison of the frequencies of false positives in no template controls (NTC) and below-LOD results in technical replicates. In the eDNA-based approach, the use of this method led to an increase in Bd and Bsal detection of 28 and 50% respectively. In swabbing, this resulted in 8% more positive results for Bd. In some samples, the use of technical replicates allowed to recover above-LOD signals and increase Bd detection by 35 and 33% respectively for eDNA and swabbing, and Bsal detection by 25% for eDNA. CONCLUSIONS These results confirmed the usefulness of technical replicates to overcome high levels of stochasticity in very low concentration samples even for a highly sensitive technique such as ddPCR. In addition, it showed that below-LOD signals could be consistently recovered and the corresponding amplification events assigned either to positive or negative detection via the method developed here. This methodology might be particularly worth pursuing in pathogenic agents' detection as false negatives could have important adverse consequences. In total, 15 ponds were found positive for Bd and four for Bsal. This study reports the first record of Bsal in Luxembourg.
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Affiliation(s)
- David Porco
- Musée national d'histoire naturelle du Luxembourg, 25, rue Münster, Luxembourg, L-2160, Luxembourg.
- Fondation Faune Flore, 24, rue Münster, Luxembourg, L-2160, Luxembourg.
| | - Chanistya Ayu Purnomo
- Musée national d'histoire naturelle du Luxembourg, 25, rue Münster, Luxembourg, L-2160, Luxembourg
| | - Liza Glesener
- Naturschutzsyndikat SICONA, 12, rue de Capellen, L-8393 Olm, Luxembourg, Luxembourg
| | - Roland Proess
- Umweltplanungsbüro Ecotop, 45, Schlassuecht, L-7435 Hollenfels, Luxembourg, Luxembourg
| | - Stéphanie Lippert
- Musée national d'histoire naturelle du Luxembourg, 25, rue Münster, Luxembourg, L-2160, Luxembourg
| | - Kevin Jans
- Natur&ëmwelt Fondation Hëllef fir d'Natur, 5, Route de Luxembourg, L-1899, Kockelscheuer, Luxembourg
| | - Guy Colling
- Musée national d'histoire naturelle du Luxembourg, 25, rue Münster, Luxembourg, L-2160, Luxembourg
- Fondation Faune Flore, 24, rue Münster, Luxembourg, L-2160, Luxembourg
| | - Simone Schneider
- Musée national d'histoire naturelle du Luxembourg, 25, rue Münster, Luxembourg, L-2160, Luxembourg
- Naturschutzsyndikat SICONA, 12, rue de Capellen, L-8393 Olm, Luxembourg, Luxembourg
| | - Raf Stassen
- Biota.lu, 9a, Rue Principale, L-6990, Hostert, Luxembourg
| | - Alain C Frantz
- Musée national d'histoire naturelle du Luxembourg, 25, rue Münster, Luxembourg, L-2160, Luxembourg
- Fondation Faune Flore, 24, rue Münster, Luxembourg, L-2160, Luxembourg
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Arnold H, Drake JF, Swisdak M, Guo F, Dahlin JT, Chen B, Fleishman G, Glesener L, Kontar E, Phan T, Shen C. Electron Acceleration during Macroscale Magnetic Reconnection. Phys Rev Lett 2021; 126:135101. [PMID: 33861105 DOI: 10.1103/physrevlett.126.135101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/19/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
The first self-consistent simulations of electron acceleration during magnetic reconnection in a macroscale system are presented. Consistent with solar flare observations, the spectra of energetic electrons take the form of power laws that extend more than two decades in energy. The drive mechanism for these nonthermal electrons is Fermi reflection in growing and merging magnetic flux ropes. A strong guide field suppresses the production of nonthermal electrons by weakening the Fermi drive mechanism. For a weak guide field the total energy content of nonthermal electrons dominates that of the hot thermal electrons even though their number density remains small. Our results are benchmarked with the hard x-ray, radio, and extreme ultraviolet observations of the X8.2-class solar flare on September 10, 2017.
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Affiliation(s)
- H Arnold
- IREAP, University of Maryland, College Park, Maryland 20742-3511, USA
| | - J F Drake
- IREAP, University of Maryland, College Park, Maryland 20742-3511, USA
| | - M Swisdak
- IREAP, University of Maryland, College Park, Maryland 20742-3511, USA
| | - F Guo
- Los Alamos National Lab, Los Alamos, New Mexico 87545, USA
| | - J T Dahlin
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Chen
- New Jersey Institute of technology, Newark, New Jersey 07102, USA
| | - G Fleishman
- New Jersey Institute of technology, Newark, New Jersey 07102, USA
| | - L Glesener
- University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - E Kontar
- University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - T Phan
- University of California, Berkeley, California 94720, USA
| | - C Shen
- Harvard University, Cambridge, Massachusetts 02138, USA
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