1
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Schwarzenberger A. Negative Effects of Cyanotoxins and Adaptative Responses of Daphnia. Toxins (Basel) 2022; 14:toxins14110770. [PMID: 36356020 PMCID: PMC9694520 DOI: 10.3390/toxins14110770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/02/2022] [Accepted: 11/05/2022] [Indexed: 11/10/2022] Open
Abstract
The plethora of cyanobacterial toxins are an enormous threat to whole ecosystems and humans. Due to eutrophication and increases in lake temperatures from global warming, changes in the distribution of cyanobacterial toxins and selection of few highly toxic species/ strains are likely. Globally, one of the most important grazers that controls cyanobacterial blooms is Daphnia, a freshwater model organism in ecology and (eco)toxicology. Daphnia-cyanobacteria interactions have been studied extensively, often focusing on the interference of filamentous cyanobacteria with Daphnia's filtering apparatus, or on different nutritional constraints (the lack of essential amino acids or lipids) and grazer toxicity. For a long time, this toxicity only referred to microcystins. Currently, the focus shifts toward other deleterious cyanotoxins. Still, less than 10% of the total scientific output deals with cyanotoxins that are not microcystins; although these other cyanotoxins can occur just as frequently and at similar concentrations as microcystins in surface water. This review discusses the effects of different cyanobacterial toxins (hepatotoxins, digestive inhibitors, neurotoxins, and cytotoxins) on Daphnia and provides an elaborate and up-to-date overview of specific responses and adaptations of Daphnia. Furthermore, scenarios of what we can expect for the future of Daphnia-cyanobacteria interactions are described by comprising anthropogenic threats that might further increase toxin stress in Daphnia.
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Affiliation(s)
- Anke Schwarzenberger
- Limnological Institute, University Konstanz, Mainaustr. 252, 78464 Konstanz, Germany
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2
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Bednarska A. Food quantity and quality shapes reproductive strategies of Daphnia. Ecol Evol 2022; 12:e9163. [PMID: 35928798 PMCID: PMC9343855 DOI: 10.1002/ece3.9163] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/04/2022] [Accepted: 07/12/2022] [Indexed: 11/22/2022] Open
Abstract
In freshwater environments, one of the challenges aquatic grazers face are periods of suboptimal food quantity and quality. In a life table experiment, the effects of food quantity (a gradient of algae concentration) and quality (a diet of cyanobacteria) on the life histories and resource allocation strategy in Daphnia magna were tested. Growth‐related traits were similarly affected under different food regimes while the reproductive strategies differed in animals exposed to low food quantity and quality. The per‐clutch investment (clutch volume) did not differ between Daphnia fed with cyanobacteria and underfed mothers, but resources were differently allocated; underfed mothers increased their per‐offspring investment by producing fewer, but larger eggs, whereas cyanobacteria‐fed mothers invested in a greater number of eggs of smaller size. I argue that both strategies of resource allocation (number vs. size of eggs) may be adaptive under the given food regime. The results of the study show that the cyanobacteria diet‐driven fitness losses are comparable to losses caused by food quantity, which is only slightly above the growth capability threshold for Daphnia.
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Affiliation(s)
- Anna Bednarska
- Department of Hydrobiology, Institute of Functional Biology and Ecology, Faculty of Biology University of Warsaw Warsaw Poland
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3
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Xu X, Cao Y, Qi H, Deng D, Zhang Y, Wu J, Peng S, Zhou Z. Effects of toxic
Microcystis aeruginosa
on the expression of Hox genes in
Daphnia similoides sinensis. Ecol Evol 2022; 12:e8685. [PMID: 35342603 PMCID: PMC8928896 DOI: 10.1002/ece3.8685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 01/25/2022] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Lake eutrophication and cyanobacterial blooms have become worldwide environmental issues. Under cyanobacterial blooms (especially Microcystis), Daphnia spp. can transfer beneficial information to their offspring in order to improve adaptability. Hox genes are important regulatory factors of transcription in metazoans, and are involved in the growth and development of organisms. However, the mechanisms of Microcystis on the expression of Hox genes in Daphnia are unclear. In this study, the effects of Microcystis aeruginosa on Hox gene expression in the mothers and offspring (F1) of two Daphnia similoides sinensis clones were investigated using a mixed diet of M. aeruginosa and Scenedesmus obliquus. Compared with the 100%S food treatment, the survival rates at the end of the experiment of clone 1‐F1 in the food treatments containing M. aeruginosa were significantly lower, but it was significantly higher for clone 2‐F1 in the 20%M + 80%S food treatment. Moreover, the survival rates at the end of the experiment of clone 1‐F1 in the food treatments containing M. aeruginosa were significantly higher than those of their mother. Based on previous transcriptome data, 14 Hox genes of D. similoides sinensis were identified, including Abd‐B, CDX‐1, Dll, HOX‐1, HOX‐2, HOXA1, HOXA2, HOXB3, HOXB3‐2, HOXB7, HOXC4, HOXC7, HOXC8, and HOXD10. The expressions of Abd‐B, HOX‐2, HOXA1, HOXC7, and HOXD10 of clone 2‐mothers in the 40%M + 60%S food treatment were 2.9–22.5 times as high as in the 100%S food treatment, whereas the expressions of CDX‐1, HOX‐1, HOXB3, and HOXD10 of clone 1‐mothers were 4.8–13.1 times at same food level. The expression of HOXA2, HOXC7, HOXC8, and HOXD10 of clone 1‐F1 in the 40%M + 60%S food treatment was 8.2–21.1 times as high as in the 100%S food treatment. However, compared with the 100%S food treatment, the expressions of CDX‐1 in the mothers and F1 of clone 2 and HOXB7 in the mothers of clone 1 in the food treatments containing M. aeruginosa were significantly lower (p < .05). Our results suggest that the offspring (F1) produced by D. similoides sinensis mother pre‐exposed to toxic M. aeruginosa had stronger adaptability to M. aeruginosa than their mothers. Moreover, Hox gene expressions of D. similoides sinensis had obvious differences between clones under stress of toxic M. aeruginosa.
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Affiliation(s)
- Xiaoxue Xu
- School of Life Science Huaibei Normal University Huaibei Anhui China
- School of Resources and Environmental Engineering Anhui University Hefei Anhui China
| | - Yaqin Cao
- School of Life Science Huaibei Normal University Huaibei Anhui China
| | - Huiying Qi
- School of Life Science Huaibei Normal University Huaibei Anhui China
| | - Daogui Deng
- School of Life Science Huaibei Normal University Huaibei Anhui China
| | - Ya‐Nan Zhang
- School of Life Science Huaibei Normal University Huaibei Anhui China
| | - Jianxun Wu
- School of Life Science Huaibei Normal University Huaibei Anhui China
- School of Resources and Environmental Engineering Anhui University Hefei Anhui China
| | - Shuixiu Peng
- School of Life Science Huaibei Normal University Huaibei Anhui China
| | - Zhongze Zhou
- School of Resources and Environmental Engineering Anhui University Hefei Anhui China
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4
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Walsh MR, Gillis MK. Transgenerational plasticity in the eye size of Daphnia. Biol Lett 2021; 17:20210143. [PMID: 34129799 PMCID: PMC8205523 DOI: 10.1098/rsbl.2021.0143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/21/2021] [Indexed: 11/12/2022] Open
Abstract
It is well established that environmental signals can induce phenotypic responses that persist for multiple generations. The induction of such 'transgenerational plasticity' (TGP) depends upon the ability of organisms to accurately receive and process information from environmental signals. Thus, sensory systems are likely intertwined with TGP. Here we tested the link between an environmental stressor and transgenerational responses in a component of the sensory system (eye size) that is linked to enhanced vision and ecologically relevant behaviours. We reared 45 clones of Daphnia pulicaria in the presence and absence of a low-quality resource (cyanobacteria) and evaluated shifts in relative eye size in offspring. Our results revealed divergent shifts in relative eye size within- and across-generations. Parental Daphnia that were fed cyanobacteria produced a smaller eye than Daphnia fed high-quality algae. Such differences were then reversed in the offspring generation; Daphnia whose mothers were fed cyanobacteria produced larger eyes than Daphnia that were continually fed green algae. We discuss the extent to which this maternal effect on eye size is an adaptive response linked to improved foraging.
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Affiliation(s)
- Matthew R. Walsh
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Michael K. Gillis
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
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5
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Schwarzenberger A, Ilić M, Von Elert E. Daphnia populations are similar but not identical in tolerance to different protease inhibitors. HARMFUL ALGAE 2021; 106:102062. [PMID: 34154785 DOI: 10.1016/j.hal.2021.102062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/06/2021] [Accepted: 05/30/2021] [Indexed: 06/13/2023]
Abstract
Cyanobacterial blooms often produce different classes and chemical variants of toxins such as dietary protease inhibitors (PIs) that affect the keystone grazer Daphnia. However, it has been shown that Daphnia populations are able to locally adapt to frequently occurring dietary PIs by modulating their digestive proteases. Up until now, local adaptation has exclusively been tested by making use of single cyanobacterial strains and by measuring average population tolerance. In contrast, we measured juvenile somatic growth rates and egg numbers of several individual clones per each of three different D. magna populations that have previously been found to be either tolerant or sensitive to the Microcystis strain BM25. Clones from the three D. magna populations were either treated with BM25 that produces three different protease inhibitor variants of the class of Ahp-cyclodepsipeptides or another Microcystis strain that produces two other Ahp-cyclodepsipeptide variants. Subsequently, the population growth was calculated as mean of the single-clone growth rates. Both tolerant populations (which originate from ponds with a cyanobacterial history) proved to be similarly tolerant to both Microcystis strains. However, single genotypes of the populations differed in their response to the different strains. Both the tolerant and the sensitive populations contained both sensitive and tolerant genotypes but in different proportions. Furthermore, the genotypes from the sensitive population showed a higher variance in response to one or both strains. Trade-offs between somatic growth rate and clutch size were found in one of the tolerant populations that originated from a pond where cyanobacteria were frequent in the past but completely absent since the pond's restoration. Because of those intra-population difference, we conclude that the tolerant populations were putatively selected by different Ahp-cyclodepsipeptide variants in the past and that all populations still possess the potential to adapt to other environmental conditions by genotype frequency shifts.
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Affiliation(s)
- Anke Schwarzenberger
- University of Konstanz, Limnological Institute, Mainaustraße 252, 78464 Konstanz, Germany.
| | - Maja Ilić
- Queen's University Belfast, School of Biological Sciences, 19 Chlorine Gardens, BT9 5DL Belfast, United Kingdom
| | - Eric Von Elert
- University of Cologne, Institute for Zoology, Zülpicherstraße 47b, 50674 Cologne, Germany
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6
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Schwarzenberger A, Martin-Creuzburg D. Daphnia's Adaptive Molecular Responses to the Cyanobacterial Neurotoxin Anatoxin-α Are Maternally Transferred. Toxins (Basel) 2021; 13:toxins13050326. [PMID: 33946510 PMCID: PMC8147185 DOI: 10.3390/toxins13050326] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/27/2021] [Accepted: 04/29/2021] [Indexed: 11/16/2022] Open
Abstract
Cyanobacterial blooms are an omnipresent and well-known result of eutrophication and climate change in aquatic systems. Cyanobacteria produce a plethora of toxic secondary metabolites that affect humans, animals and ecosystems. Many cyanotoxins primarily affect the grazers of phytoplankton, e.g., Daphnia. The neurotoxin anatoxin-α has been reported world-wide; despite its potency, anatoxin-α and its effects on Daphnia have not been thoroughly investigated. Here, we investigated the effects of the anatoxin-α-producing Tychonema on life-history parameters and gene expression of nicotine-acetylcholine receptors (NAR), the direct targets of anatoxin-α, using several D. magna clones. We used juvenile somatic growth rates as a measure of fitness and analyzed gene expression by qPCR. Exposure to 100% Tychonema reduced the clones' growth rates and caused an up-regulation of NAR gene expression. When 50% of the food consisted of Tychonema, none of the clones were reduced in growth and only one of them showed an increase in NAR gene expression. We demonstrate that this increased NAR gene expression can be maternally transferred and that offspring from experienced mothers show a higher growth rate when treated with 50% Tychonema compared with control offspring. However, the addition of further (anthropogenic) stressors might impair Daphnia's adaptive responses to anatoxin-α. Especially the presence of certain pollutants (i.e., neonicotinoids), which also target NARs, might reduce Daphnia's capability to cope with anatoxin-α.
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7
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Schwarzenberger A, Kurmayer R, Martin-Creuzburg D. Toward Disentangling the Multiple Nutritional Constraints Imposed by Planktothrix: The Significance of Harmful Secondary Metabolites and Sterol Limitation. Front Microbiol 2020; 11:586120. [PMID: 33193235 PMCID: PMC7609654 DOI: 10.3389/fmicb.2020.586120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/15/2020] [Indexed: 11/13/2022] Open
Abstract
The harmful bloom-forming cyanobacterium Planktothrix is commonly considered to be nutritionally inadequate for zooplankton grazers, resulting in limited top-down control. However, interactions between Planktothrix and zooplankton grazers are poorly understood. The food quality of Planktothrix is potentially constrained by morphological properties (i.e., filament formation), the production of harmful secondary metabolites, and a deficiency in essential lipids (i.e., primarily sterols). Here, we investigated the relative significance of toxin production (microcystins, carboxypeptidase A inhibitors, protease inhibitors) and sterol limitation for the performance of Daphnia feeding on one Planktothrix rubescens and one P. agardhii wild-type/microcystin knock-out mutant pair. Our data suggest that the poor food quality of both Planktothrix spp. is due to deleterious effects mediated by various harmful secondary metabolites and that the impact of sterol limitation is partially or completely superimposed by toxicity. The significance of the different factors seems to depend on the metabolite profile of the considered Planktothrix strain and the Daphnia clone that is used for the experiments. The toxin-responsive gene expression (transporter genes, gpx, and trypsin) and enzyme activity patterns revealed strain-specific food quality constraints and that Daphnia is capable of modulating its physiological responses according to the ingested Planktothrix strain. Future studies need to consider that Planktothrix-grazer interactions are simultaneously modulated by multiple factors to improve our understanding of top-down influences on Planktothrix bloom formation.
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Affiliation(s)
| | - Rainer Kurmayer
- Research Department for Limnology, University of Innsbruck, Innsbruck, Austria
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8
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Schwarzenberger A, Hasselmann M, Elert E. Positive selection of digestive proteases inDaphnia: A mechanism for local adaptation to cyanobacterial protease inhibitors. Mol Ecol 2020; 29:912-919. [DOI: 10.1111/mec.15375] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/17/2020] [Accepted: 01/29/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Anke Schwarzenberger
- Limnological Institute Konstanz University Konstanz Germany
- Cologne Biocenter Aquatic Chemical Ecology University of Cologne Cologne Germany
| | - Martin Hasselmann
- Department of Livestock Population Genomics Institute of Animal Science University of Hohenheim Stuttgart Germany
| | - Eric Elert
- Cologne Biocenter Aquatic Chemical Ecology University of Cologne Cologne Germany
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9
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Burberg C, Petzoldt T, von Elert E. Phosphate Limitation Increases Content of Protease Inhibitors in the Cyanobacterium Microcystis aeruginosa. Toxins (Basel) 2020; 12:E33. [PMID: 31935921 PMCID: PMC7020438 DOI: 10.3390/toxins12010033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 12/21/2019] [Accepted: 01/01/2020] [Indexed: 01/12/2023] Open
Abstract
Increased anthropogenic nutrient input has led to eutrophication of lakes and ponds, resulting worldwide in more frequent and severe cyanobacterial blooms. In particular, enhanced availability of phosphorus (P) can promote cyanobacterial mass developments and may affect the content of secondary metabolites in cyanobacteria, such as protease inhibitors (PIs). PIs are common among cyanobacteria and have been shown to negatively affect herbivorous zooplankton. Here, we test the hypothesis that P-limitation reduces the growth of Microcystis, but increases the content of PIs. In batch culture experiments with eight different initial phosphate concentrations (5-75 µM) we determined growth, stoichiometry, and PI content of Microcystis aeruginosa NIVA Cya 43. This strain produces the protease inhibitor BN920 that is converted by chlorination to CP954, which constitutes the major PI in this strain. C:N:P-ratios of the biomass indicated variation of P-limitation with treatment and time. When normalized to biomass, the PI content varied up to nearly nineteen-fold with treatment and time and was highest in the low-P treatments, especially during the mid-exponential growth phase. However, these effects were alleviated under nitrogen co-limitation. The content of CP954 showed an inverse u-shaped response to growth rate and C:N-ratio of the cyanobacterial biomass, whereas it increased with cyanobacterial C:P. The results indicate that P-limitation supports a higher content of defensive PIs and may indirectly foster cyanobacterial blooms by increasing the negative interference of cyanobacteria with their consumers.
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Affiliation(s)
- Christian Burberg
- Workgroup Aquatic Chemical Ecology, Institute for Zoology, University of Cologne, 50674 Cologne, Germany;
| | - Thomas Petzoldt
- Institute of Hydrobiology, Technische Universität (TU) Dresden, 01062 Dresden, Germany;
| | - Eric von Elert
- Workgroup Aquatic Chemical Ecology, Institute for Zoology, University of Cologne, 50674 Cologne, Germany;
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10
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Gillis MK, Walsh MR. Individual variation in plasticity dulls transgenerational responses to stress. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Michael K. Gillis
- Department of Biology University of Texas at Arlington Arlington TX USA
| | - Matthew R. Walsh
- Department of Biology University of Texas at Arlington Arlington TX USA
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11
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Ferrão-Filho ADS, Dias TM, Pereira UJ, Dos Santos JAA, Kozlowsky-Suzuki B. Nutritional and toxicity constraints of phytoplankton from a Brazilian reservoir to the fitness of cladoceran species. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:12881-12893. [PMID: 30887454 DOI: 10.1007/s11356-019-04851-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/12/2019] [Indexed: 06/09/2023]
Abstract
Camorim is a small, eutrophic reservoir in Rio de Janeiro, Brazil, with a phytoplankton community dominated most of the year by the filamentous diatom Aulacoseira spp. and the toxic cyanobacterium Cylindrospermopsis raciborskii. As filamentous species can be a poor food for grazers, we hypothesize that phytoplankton from this reservoir would constrain cladoceran fitness due to nutritional limitation and/or toxicity when animals fed mixtures of cultured green algae and natural seston. Clones of different cladoceran species were exposed either to seston from Camorim reservoir sampled in different seasons or to a C. raciborskii strain (CYLCAM-2) isolated from the reservoir. In short-term assays, cladocerans were exposed to either 100% seston or mixtures of 50% seston added to green algae (200 μg C L-1), and their survivorship and somatic growth were measured for 4 days. In life table assays, neonates were exposed to the same seston treatments over 14 days and age at first reproduction, survivorship, fecundity, total offspring, and the intrinsic rate of natural increase (r) were assessed. In general, seston negatively affected cladoceran survivorship and fitness (r), but this response was seasonally and species specific. Stronger effects of CYLCAM-2 than those caused by seston on survivorship, somatic growth, and r were found for all cladoceran species, especially when the proportion of CYLCAM-2 was higher than 50% in relation to green algae in a fixed total food concentration. Our results suggest that both nutritional (C/P and morphology) and toxicity factors can act to impair cladoceran fitness and help explain the absence of cladocerans in Camorim reservoir.
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Affiliation(s)
- Aloysio da S Ferrão-Filho
- Laboratório de Avaliação e Promoção da Saúde Ambiental, Instituto Oswaldo Cruz, FIOCRUZ, Av. Brasil, 4365-Manguinhos, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Tatiane M Dias
- Programa de Pós-Graduação em Ciências Biológicas (Biodiversidade Neotropical), Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Av. Pasteur 458, Urca, Rio de Janeiro, RJ, 22290-040, Brazil
| | - Uanderson J Pereira
- Programa de Pós-Graduação em Ciências Biológicas, Departamento de Botânica, Museu Nacional, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, 21940-590, Brazil
| | - José Augusto A Dos Santos
- Laboratório de Avaliação e Promoção da Saúde Ambiental, Instituto Oswaldo Cruz, FIOCRUZ, Av. Brasil, 4365-Manguinhos, Rio de Janeiro, RJ, 21040-360, Brazil
| | - Betina Kozlowsky-Suzuki
- Departamento de Ecologia e Recursos Marinhos, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Av. Pasteur 458, Urca, Rio de Janeiro, RJ, 22290-040, Brazil.
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12
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Radersma R, Hegg A, Noble DWA, Uller T. Timing of maternal exposure to toxic cyanobacteria and offspring fitness in Daphnia magna: Implications for the evolution of anticipatory maternal effects. Ecol Evol 2018; 8:12727-12736. [PMID: 30619577 PMCID: PMC6309005 DOI: 10.1002/ece3.4700] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 10/11/2018] [Indexed: 01/22/2023] Open
Abstract
Organisms that regularly encounter stressful environments are expected to use cues to develop an appropriate phenotype. Water fleas (Daphnia spp.) are exposed to toxic cyanobacteria during seasonal algal blooms, which reduce growth and reproductive investment. Because generation time is typically shorter than the exposure to cyanobacteria, maternal effects provide information about the local conditions subsequent generations will experience. Here, we evaluate if maternal effects in response to microcystin, a toxin produced by cyanobacteria, represent an inheritance system evolved to transmit information in Daphnia magna. We exposed mothers as juveniles and/or as adults, and tested the offspring's fitness in toxic and non-toxic environments. Maternal exposure until reproduction reduced offspring fitness, both in the presence and in the absence of toxic cyanobacteria. However, this effect was accompanied by a small positive fitness effect, relative to offspring from unexposed mothers, in the presence of toxic cyanobacteria. This effect was mainly elicited in response to maternal exposure to toxic cyanobacteria early in life and less so during reproduction. None of these effects were explained by changes in egg size. A meta-analysis using our and others' experiments suggests that the adaptive value of maternal effects to cyanobacteria exposure is weak at best. We suggest that the beneficial maternal effect in our study is an example of phenotypic accommodation spanning generations, rather than a mechanism evolved to transmit information about cyanobacteria presence between generations.
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Affiliation(s)
| | | | - Daniel W. A. Noble
- Ecology and Evolution Research Centre, School of Biological, Earth and Environmental SciencesThe University of New South WalesSydneyNew South WalesAustralia
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13
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Lange J, Demir F, Huesgen PF, Baumann U, von Elert E, Pichlo C. Heterologous expression and characterization of a novel serine protease from Daphnia magna: A possible role in susceptibility to toxic cyanobacteria. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 205:140-147. [PMID: 30384195 DOI: 10.1016/j.aquatox.2018.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/21/2018] [Accepted: 09/24/2018] [Indexed: 06/08/2023]
Abstract
Mass developments of toxin-producing cyanobacteria are frequently observed in freshwater ecosystems due to eutrophication and global warming. These mass developments can partly be attributed to cyanobacterial toxins, such as protease inhibitors (PIs), which inhibit digestive serine proteases of Daphnia, the major herbivore of phytoplankton and cyanobacteria. To date, mechanisms of this inhibition in the gut of the crustacean Daphnia magna are not known. Here, we characterize a single serine protease, chymotrypsin 448 (CT448), which is present in the gut of the crustacean D. magna. Sequence alignments with human serine proteases revealed that CT448 has a putative N-terminal pro-peptide which is extended compared to the mammalian homologs and within this pro-peptide two N-linked glycosylation motifs were found. CT448 was heterologously expressed in Sf21 insect cells using a baculovirus expression system for optimized protein production and secretion into the medium. The protein was purified via a one-step affinity chromatography, which resulted in a protein yield of 3.45 mg/l medium. The inactive precursor (zymogen) could be activated by tryptic digestion. This is the first example of a recombinant expression of an active crustacean serine protease, which functions in the gut of Daphnia. Proteomic identification of protease cleavage sites (PICS) and hydrolysation of various synthetic substrates showed that CT448 is a chymotrypsin-like elastase. In this study, we confirm that CT448 is a target of cyanobacterial protease inhibitors. Local evolutionary modifications of CT448 might render this proteolytic enzyme less susceptible against cyanobacterial secondary metabolites and might improve the fitness of Daphnia during cyanobacterial blooms.
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Affiliation(s)
- Jacqueline Lange
- Department of Aquatic Chemical Ecology, University of Cologne, 50674 Cologne, Germany.
| | - Fatih Demir
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Pitter F Huesgen
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Ulrich Baumann
- Department of Biochemistry, University of Cologne, 50674 Cologne, Germany
| | - Eric von Elert
- Department of Aquatic Chemical Ecology, University of Cologne, 50674 Cologne, Germany
| | - Christian Pichlo
- Department of Biochemistry, University of Cologne, 50674 Cologne, Germany
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14
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Macke E, Callens M, De Meester L, Decaestecker E. Host-genotype dependent gut microbiota drives zooplankton tolerance to toxic cyanobacteria. Nat Commun 2017; 8:1608. [PMID: 29151571 PMCID: PMC5694789 DOI: 10.1038/s41467-017-01714-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 10/11/2017] [Indexed: 12/20/2022] Open
Abstract
The gut microbiota impacts many aspects of its host's biology, and is increasingly considered as a key factor mediating performance of host individuals in continuously changing environments. Here we use gut microbiota transplants to show that both host genotype and gut microbiota mediate tolerance to toxic cyanobacteria in the freshwater crustacean Daphnia magna. Interclonal variation in tolerance to cyanobacteria disappears when Daphnia are made germ-free and inoculated with an identical microbial inoculum. Instead, variation in tolerance among recipient Daphnia mirrors that of the microbiota donors. Metagenetic analyses point to host genotype and external microbial source as important determinants of gut microbiota assembly, and reveal strong differences in gut microbiota composition between tolerant and susceptible genotypes. Together, these results show that both environmentally and host genotype-induced variations in gut microbiota structure mediate Daphnia tolerance to toxic cyanobacteria, pointing to the gut microbiota as a driver of adaptation and acclimatization to cyanobacterial harmful algal blooms in zooplankton.
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Affiliation(s)
- Emilie Macke
- Laboratory of Aquatic Biology, Department of Biology, University of Leuven-Campus Kulak, E. Sabbelaan 53, B-8500, Kortrijk, Belgium.
| | - Martijn Callens
- Laboratory of Aquatic Biology, Department of Biology, University of Leuven-Campus Kulak, E. Sabbelaan 53, B-8500, Kortrijk, Belgium
| | - Luc De Meester
- Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Charles Deberiotstraat 32, 3000, Leuven, Belgium
| | - Ellen Decaestecker
- Laboratory of Aquatic Biology, Department of Biology, University of Leuven-Campus Kulak, E. Sabbelaan 53, B-8500, Kortrijk, Belgium.
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da S Ferrão-Filho A, de Abreu S Silva D, de Oliveira TA, de Magalhães VF, Pflugmacher S, da Silva EM. Single and combined effects of microcystin- and saxitoxin-producing cyanobacteria on the fitness and antioxidant defenses of cladocerans. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:2689-2697. [PMID: 28409869 DOI: 10.1002/etc.3819] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/16/2016] [Accepted: 04/09/2017] [Indexed: 06/07/2023]
Abstract
Cyanobacteria produce different toxic compounds that affect animal life, among them hepatotoxins and neurotoxins. Because cyanobacteria are able to produce a variety of toxic compounds at the same time, organisms may be, generally, subjected to their combined action. In the present study, we demonstrate the single and combined effects on cladocerans of cyanobacteria that produce microcystins (hepatotoxins) and saxitoxins (neurotoxins). Animals were exposed (either singly or combined) to 2 strains of cyanobacteria isolated from the same environment (Funil Reservoir, Rio de Janeiro, Brazil). The effects on clearance rate, mobility, survivorship, fecundity, population increase rate (r), and the antioxidant enzymes glutathione-S-transferase (GST) and catalase (CAT) were measured. Cladoceran species showed a variety of responses to cyanobacterial exposures, going from no effect to impairment of swimming movement, lower survivorship, fecundity, and general fitness (r). Animals ingested cyanobacteria in all treatments, although at lower rates than good food (green algae). Antioxidant defense responses were in accordance with fitness responses, suggesting that oxidative stress may be related to such effects. The present study emphasizes the need for testing combined actions of different classes of toxins, because this is often, and most likely, the scenario in a more eutrophic world with global climatic changes. Environ Toxicol Chem 2017;36:2689-2697. © 2017 SETAC.
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Affiliation(s)
| | | | | | - Valéria Freitas de Magalhães
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Stephan Pflugmacher
- Institute of Ecology, Chair of Ecological Impact Research & Ecotoxicology, Technische Universität Berlin, Berlin, Germany
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16
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Microcystis aeruginosa strengthens the advantage of Daphnia similoides in competition with Moina micrura. Sci Rep 2017; 7:10245. [PMID: 28860619 PMCID: PMC5579008 DOI: 10.1038/s41598-017-10844-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/15/2017] [Indexed: 12/14/2022] Open
Abstract
Microcystis blooms are generally associated with zooplankton shifts by disturbing interspecific relationships. The influence of Microcystis on competitive dominance by different sized zooplanktons showed species-specific dependence. We evaluated the competitive responses of small Moina micrura and large Daphnia similoides to the presence of Microcystis using mixed diets comprising 0%, 20%, and 35% of toxic M. aeruginosa, and the rest of green alga Chlorella pyrenoidosa. No competitive exclusion occurred for the two species under the tested diet combinations. In the absence of M. aeruginosa, the biomasses of the two cladocerans were decreased by the competition between them. However, the Daphnia was less inhibited with the higher biomass, suggesting the competitive dominance of Daphnia. M. aeruginosa treatment suppressed the population growths of the two cladocerans, with the reduced carrying capacities. Nonetheless, the population inhibition of Daphnia by competition was alleviated by the increased Microcystis proportion in diet. As a result, the competitive advantage of Daphnia became more pronounced, as indicated by the higher Daphnia: Moina biomass ratio with increased Microcystis proportions. These results suggested that M. aeruginosa strengthens the advantage of D. similoides in competition with M. micrura, which contributes to the diversified zooplankton shifts observed in fields during cyanobacteria blooms.
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17
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Entfellner E, Frei M, Christiansen G, Deng L, Blom J, Kurmayer R. Evolution of Anabaenopeptin Peptide Structural Variability in the Cyanobacterium Planktothrix. Front Microbiol 2017; 8:219. [PMID: 28261178 PMCID: PMC5311044 DOI: 10.3389/fmicb.2017.00219] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 01/31/2017] [Indexed: 11/22/2022] Open
Abstract
Cyanobacteria are frequently involved in the formation of harmful algal blooms wherein, apart from the toxic microcystins, other groups of bioactive peptides are abundant as well, such as anabaenopeptins (APs). The APs are synthesized nonribosomally as cyclic hexapeptides with various amino acids at the exocyclic position. We investigated the presence and recombination of the AP synthesis gene cluster (apnA-E) through comparing 125 strains of the bloom-forming cyanobacterium Planktothrix spp., which were isolated from numerous shallow and deep water habitats in the temperate and tropical climatic zone. Ten ecologically divergent strains were purified and genome sequenced to compare their entire apnA-E gene cluster. In order to quantify apn gene distribution patterns, all the strains were investigated by PCR amplification of 2 kbp portions of the entire apn gene cluster without interruption. Within the 11 strains assigned to P. pseudagardhii, P. mougeotii, or P. tepida (Lineage 3), neither apnA-E genes nor remnants were observed. Within the P. agardhii/P. rubescens strains from shallow waters (Lineage 1, 52 strains), strains both carrying and lacking apn genes occurred, while among the strains lacking the apnA-E genes, the presence of the 5'end flanking region indicated a gene cluster deletion. Among the strains of the more derived deep water ecotype (Lineage 2, 62 strains), apnA-E genes were always present. A high similarity of apn genes of the genus Planktothrix when compared with strains of the genus Microcystis suggested its horizontal gene transfer during the speciation of P. agardhii/P. rubescens. Genetic analysis of the first (A1-) domain of the apnA gene, encoding synthesis of the exocyclic position of the AP molecule, revealed four genotype groups that corresponded with substrate activation. Groups of genotypes were either related to Arginine only, the coproduction of Arginine and Tyrosine or Arginine and Lysine, or even the coproduction of Arginine, Tyrosine, and Lysine in the exocyclic position of the AP-molecule. The increased structural diversity resulted from the evolution of apnA A1 genotypes through a small number of positively selected point mutations that occurred repeatedly and independently from phylogenetic association.
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Affiliation(s)
| | - Mark Frei
- Research Institute for Limnology, University of InnsbruckMondsee, Austria
| | - Guntram Christiansen
- Research Institute for Limnology, University of InnsbruckMondsee, Austria
- Miti Biosystems GmbH, Max F Perutz LaboratoriesWien, Austria
| | - Li Deng
- Institute of Virology, Helmholtz Zentrum MünchenMünchen, Germany
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-UniversityGiessen, Germany
| | - Rainer Kurmayer
- Research Institute for Limnology, University of InnsbruckMondsee, Austria
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Schwarzenberger A, Sadler T, Motameny S, Ben-Khalifa K, Frommolt P, Altmüller J, Konrad K, von Elert E. Deciphering the genetic basis of microcystin tolerance. BMC Genomics 2014; 15:776. [PMID: 25199885 PMCID: PMC4168211 DOI: 10.1186/1471-2164-15-776] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/29/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cyanobacteria constitute a serious threat to freshwater ecosystems by producing toxic secondary metabolites, e.g. microcystins. These microcystins have been shown to harm livestock, pets and humans and to affect ecosystem service and functioning. Cyanobacterial blooms are increasing worldwide in intensity and frequency due to eutrophication and global warming. However, Daphnia, the main grazer of planktonic algae and cyanobacteria, has been shown to be able to suppress bloom-forming cyanobacteria and to adapt to cyanobacteria that produce microcystins. Since Daphnia's genome was published only recently, it is now possible to elucidate the underlying molecular mechanisms of microcystin tolerance of Daphnia. RESULTS Daphnia magna was fed with either a cyanobacterial strain that produces microcystins or its genetically engineered microcystin knock-out mutant. Thus, it was possible to distinguish between effects due to the ingestion of cyanobacteria and effects caused specifically by microcystins. By using RNAseq the differentially expressed genes between the different treatments were analyzed and affected KOG-categories were calculated. Here we show that the expression of transporter genes in Daphnia was regulated as a specific response to microcystins. Subsequent qPCR and dietary supplementation with pure microcystin confirmed that the regulation of transporter gene expression was correlated with the tolerance of several Daphnia clones. CONCLUSIONS Here, we were able to identify new candidate genes that specifically respond to microcystins by separating cyanobacterial effects from microcystin effects. The involvement of these candidate genes in tolerance to microcystins was validated by correlating the difference in transporter gene expression with clonal tolerance. Thus, the prevention of microcystin uptake most probably constitutes a key mechanism in the development of tolerance and adaptation of Daphnia. With the availability of clear candidate genes, future investigations examining the process of local adaptation of Daphnia populations to microcystins are now possible.
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Affiliation(s)
- Anke Schwarzenberger
- University of Cologne, Cologne Biocenter, Aquatic Chemical Ecology, Zuelpicher Str, 47b, 50674 Cologne, Germany.
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Jiang X, Li Q, Liang H, Zhao S, Zhang L, Zhao Y, Chen L, Yang W, Xiang X. Clonal variation in growth plasticity within a Bosmina longirostris population: the potential for resistance to toxic cyanobacteria. PLoS One 2013; 8:e73540. [PMID: 24039976 PMCID: PMC3767689 DOI: 10.1371/journal.pone.0073540] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 07/21/2013] [Indexed: 11/19/2022] Open
Abstract
Many aquatic organisms respond phenotypically, through morphological, behavioral, and physiological plasticity, to environmental changes. The small-size cladoceran Bosminalongirostris, a dominant zooplankter in eutrophic waters, displayed reduced growth rates in response to the presence of a toxic cyanobacterium, Microcystisaeruginosa, in their diets. The magnitude of growth reduction differed among 15 clones recently isolated from a single population. A significant interaction between clone and food type indicated a genetic basis for the difference in growth plasticity. The variation in phenotypic plasticity was visualized by plotting reaction norms with two diets. The resistance of each clone to dietary cyanobacteria was measured as the relative change in growth rates on the "poor" diet compared with the "good" diet. The enhanced resistance to M. aeruginosa in B. longirostris was derived from both the reduced slope of reaction norms and the increased mean growth rates with two diets. The large clonal variation within a B. longirostris population may contribute to local adaptation to toxic cyanobacteria and influence ecosystem function via clonal succession.
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Affiliation(s)
- Xiaodong Jiang
- School of Life Science, East China Normal University, Shanghai, China
- * E-mail:
| | - Qingmei Li
- School of Life Science, East China Normal University, Shanghai, China
| | - Huishuang Liang
- School of Life Science, East China Normal University, Shanghai, China
| | - Shiye Zhao
- School of Life Science, East China Normal University, Shanghai, China
| | - Lihua Zhang
- School of Life Science, East China Normal University, Shanghai, China
| | - Yunlong Zhao
- School of Life Science, East China Normal University, Shanghai, China
| | - Liqiao Chen
- School of Life Science, East China Normal University, Shanghai, China
| | - Wei Yang
- School of Life Science, East China Normal University, Shanghai, China
| | - Xingyu Xiang
- School of Life Science, East China Normal University, Shanghai, China
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Kuster CJ, Von Elert E. Interspecific differences between D. pulex and D. magna in tolerance to cyanobacteria with protease inhibitors. PLoS One 2013; 8:e62658. [PMID: 23650523 PMCID: PMC3641091 DOI: 10.1371/journal.pone.0062658] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/25/2013] [Indexed: 12/03/2022] Open
Abstract
It is known that cyanobacteria negatively affect herbivores due to their production of toxins such as protease inhibitors. In the present study we investigated potential interspecific differences between two major herbivores, Daphnia magna and Daphnia pulex, in terms of their tolerance to cyanobacteria with protease inhibitors. Seven clones each of D. magna and of D. pulex were isolated from different habitats in Europe and North America. To test for interspecific differences in the daphnids’ tolerance to cyanobacteria, their somatic and population growth rates were determined for each D. magna and D. pulex clone after exposure to varying concentrations of two Microcystis aeruginosa strains. The M. aeruginosa strains NIVA and PCC− contained either chymotrypsin or trypsin inhibitors, but no microcystins. Mean somatic and population growth rates on a diet with 20% NIVA were significantly more reduced in D. pulex than in D. magna. On a diet with 10% PCC−, the population growth of D. pulex was significantly more reduced than that of D. magna. This indicates that D. magna is more tolerant to cyanobacteria with protease inhibitors than D. pulex. The reduction of growth rates was possibly caused by an interference of cyanobacterial inhibitors with proteases in the gut of Daphnia, as many other conceivable factors, which might have been able to explain the reduced growth, could be excluded as causal factors. Protease assays revealed that the sensitivities of chymotrypsins and trypsins to cyanobacterial protease inhibitors did not differ between D. magna and D. pulex. However, D. magna exhibited a 2.3-fold higher specific chymotrypsin activity than D. pulex, which explains the observed higher tolerance to cyanobacterial protease inhibitors of D. magna. The present study suggests that D. magna may control the development of cyanobacterial blooms more efficiently than D. pulex due to differences in their tolerance to cyanobacteria with protease inhibitors.
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Affiliation(s)
- Christian J Kuster
- Zoological Institute, Aquatic Chemical Ecology, University of Cologne, Cologne, Germany.
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