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1.
Sci Total Environ ; 919: 170837, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38350569

ABSTRACT

Microplastics (MPs) accumulating in freshwater sediment have raised concerns about potential risks to benthic dwelling organisms, yet few studies have examined the long-term impacts caused by MP exposure. This study investigated alterations to lipid profiles in an Australian freshwater invertebrate, Chironomus tepperi, induced by polyethylene MP fragments (1-45 µm) at environmentally relevant concentrations (125, 250, 500 and 1000 MPs/kg sediment), using a two-generational experimental design. In the parental generation, the relative abundance of triacylglycerols, total fatty acids and unsaturated fatty acids exhibited apparent hormetic patterns, with low-concentration stimulation and high-concentration inhibition observed. The overall trend in these lipid classes is consistent with previously observed changes to polar metabolite profiles, indicating that ingestion of MPs could inhibit nutrient assimilation from food leading to disruption of energy availability. In the first filial generation continuously exposed to MPs, however, abundance of cholesterol and total fatty acids increased with increasing exposure concentrations, suggesting different effects on energy metabolism between the parental generation and offspring. No differences in the lipidome were observed in first filial larvae that were not exposed, implying that MPs pose negligible carry-over effects. Overall, the combined results of this study together with a preceding metabolomics study provide evidence of a physical effect of MPs with subsequent impacts to bioenergetics. Nevertheless, future research is required to explore the potential long-term impacts caused by MPs, and to unravel the impacts of the surfactant control as a potential contributor to the observed hormetic response, particularly for studies exploring sub-lethal effects of MP exposure using sensitive omics techniques.


Subject(s)
Chironomidae , Water Pollutants, Chemical , Animals , Microplastics , Plastics , Polyethylene/toxicity , Chironomidae/physiology , Lipidomics , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/analysis , Australia , Fatty Acids , Lipids/toxicity
2.
Sci Total Environ ; 913: 169735, 2024 Feb 25.
Article in English | MEDLINE | ID: mdl-38163597

ABSTRACT

The conservation and management of riparian ecosystems rely on understanding the ecological consequences of anthropogenic stressors that impact natural communities. In this context, studies investigating the effects of anthropogenic stressors require reliable methods capable of mapping the relationships between taxa occurrence or abundance and environmental predictors within a spatio-temporal framework. Here, we present an integrative approach using DNA metabarcoding and Hierarchical Modelling of Species Communities (HMSC) to unravel the intricate dynamics and resilience of chironomid communities exposed to Bacillus thuringiensis var. israelensis (Bti). Chironomid emergence was sampled from a total of 12 floodplain pond mesocosms, half of which received Bti treatment, during a 16-week period spanning spring and summer of 2020. Subsequently, we determined the community compositions of chironomids and examined their genus-specific responses to the Bti treatment, considering their phylogenetic affiliations and ecological traits of the larvae. Additionally, we investigated the impact of the Bti treatment on the body size distribution of emerging chironomids. Our study revealed consistent responses to Bti among different chironomid genera, indicating that neither phylogenetic affiliations nor larval feeding strategies significantly contributed to the observed patterns. Both taxonomic and genetic diversity were positively correlated with the number of emerged individuals. Furthermore, our findings demonstrated Bti-related effects on chironomid body size distribution, which could have relevant implications for size-selective terrestrial predators. Hence, our study highlights the value of employing a combination of DNA metabarcoding and HMSC to unravel the complex dynamics of Bti-related non-target effects on chironomid communities. The insights gained from this integrated framework contribute to our understanding of the ecological consequences of anthropogenic stressors and provide a foundation for informed decision-making regarding the conservation and management of riparian ecosystems.


Subject(s)
Bacillus thuringiensis , Chironomidae , Culicidae , Humans , Animals , Ecosystem , Chironomidae/physiology , Mosquito Control/methods , DNA Barcoding, Taxonomic , Phylogeny , Larva , Pest Control, Biological
3.
Ecotoxicology ; 32(3): 300-308, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36905483

ABSTRACT

Microplastic (MP) is yet another form of chronic anthropogenic contribution to the environment. MPs are plastic particles (<5 mm) that have been widely found in the most diverse natural environments, but their real impacts on ecosystems are still under investigation. Here, we studied the toxicity of naturally aged secondary polypropylene (PP) MPs after constant exposure to ultraviolet radiation (26 µm) to the third instar larvae of Chironomus sancticaroli, a dipteran species. The concentrations tested were 13.5; 67.5; and 135 items g-1 of dry sediment. C. sancticaroli organisms were investigated for fragment ingestion, mortality and changes in enzymatic biomarkers after 144 h of exposure. The organisms were able to ingest MPs from the first 48 h, and the amount of items internalized was dose-dependent and time-dependent. Overall, the results show that mortality was low, being significant at the lowest and highest concentrations (13.5 and 135 items g-1). Regarding changes in biochemical markers, after 144 h MDA and CAT activities were both significantly altered (increased and reduced, respectively), while SOD and GST levels were unchanged. In the present study, naturally aged polypropylene MPs induced biochemical toxicity in C. sancticaroli larvae, with toxicity being higher according to exposure time and particle concentration.


Subject(s)
Chironomidae , Water Pollutants, Chemical , Animals , Microplastics , Plastics/toxicity , Polypropylenes/toxicity , Chironomidae/physiology , Ecosystem , Ultraviolet Rays , Water Pollutants, Chemical/toxicity , Water Pollutants, Chemical/analysis , Larva
4.
Sci Total Environ ; 879: 163110, 2023 Jun 25.
Article in English | MEDLINE | ID: mdl-36972886

ABSTRACT

Global climate change is expected to exacerbate extreme discharge events in freshwater ecosystems as a consequence of changes in precipitation volume and snow cover duration. Chironomid midges were used as a model organism in this study because of their small size and short life cycles, which enable fast colonization of new habitats and great resilience. This resilience is often expressed in easy recolonization after an extreme event. Chironomid samples together with physico-chemical water measurements were collected for 14 years, between 2007 and 2020, in a karst tufa barrier that is part of the Plitvice Lakes National Park in Croatia. More than 13,000 individuals belonging to >90 taxa were collected. Mean annual water temperature increased by 0.1 °C during this period. Multiple change-point analysis revealed three main periods by discharge patterns: the first one from January 2007 to June 2010, the second from July 2010 to March 2013, characterised by extreme low discharge, and the third from April 2013 to December 2020, characterised by an increase in extreme peak discharge values. Based on multilevel pattern analysis, indicator species of the first and the third discharge period were detected. The ecological preferences of these species indicate an environmental change related to the changes in discharge. Along with species composition, functional composition has changed with the abundance of passive filtrators, shredders and predators increasing over time. Species richness and abundance did not change over the period of observation, thus emphasizing the importance of species-level identification in detecting the earliest community response to change that would otherwise be overlooked.


Subject(s)
Chironomidae , Ecosystem , Humans , Animals , Chironomidae/physiology , Climate Change , Biodiversity , Lakes , Water
5.
Pest Manag Sci ; 79(6): 2255-2263, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36775861

ABSTRACT

BACKGROUND: Freshwater organisms are facing increasing salinity levels, not only due to natural environmental processes, but also human activities, which can cause several physiological adaptations to osmotic stress. Additionally, these organisms might also have to deal with contamination by microbial insecticides. Our main goal was to use Chironomus xanthus to assess the chronic effects of increasing the salinity and commercial formulations of the microbial insecticides based on Bacillus thuringiensis subs. kurstaki (Btk) and Beauveria bassiana (Bb) as active ingredients, respectively. RESULTS: A significant interaction of growth was observed between the biopesticide based on Bb and NaCl on the larvae of C. xanthus. Single exposure to NaCl and each one of the formulations demonstrated deleterious impacts not only on larval development, but also on the emergence success and emergence time of this nontarget insect, with potential consequences for freshwater ecosystems due to cascading effects. CONCLUSION: The chronic effects induced by both bioinsecticides show that these formulations can have environmental impacts on nontarget freshwater insects. © 2023 Society of Chemical Industry.


Subject(s)
Bacillus thuringiensis , Beauveria , Chironomidae , Insecticides , Animals , Humans , Insecticides/pharmacology , Chironomidae/physiology , Sodium Chloride/pharmacology , Ecosystem , Insecta , Larva
7.
Sci Rep ; 12(1): 3766, 2022 03 08.
Article in English | MEDLINE | ID: mdl-35260641

ABSTRACT

During desiccation the Polypedilum vanderplanki larva loses 97% of its body water, resulting in the shutdown of all metabolic and physiological processes. The larvae are able to resume active life when rehydrated. As dehydration process has already been largely understood, rehydration mechanisms are still poorly recognized. X-ray microtomograms and electron scanning microscopy images recorded during the hydration showed that the volume of the larva's head hardly changes, while the remaining parts of the body increase in volume. In the 1H-NMR spectrum, as recorded for active larvae, component characteristic of solid state matter is absent. The spectrum is superposition of components coming from tightly and loosely bound water fraction, as well as from lipids. The value of the c coefficient (0.66 ± 0.02) of the allometric function describing the hydration models means that the increase in the volume of rehydrated larvae over time is linear. The initial phase of hydration does not depend on the chemical composition of water, but the amount of ions affects the further process and the rate of return of larva's to active life. Diffusion and ion channels play a major role in the permeability of water through the larva's body integument.


Subject(s)
Chironomidae , Animals , Chemical Phenomena , Chironomidae/physiology , Fluid Therapy , Larva/physiology , Water/chemistry
8.
Sci Total Environ ; 819: 152843, 2022 May 01.
Article in English | MEDLINE | ID: mdl-35033566

ABSTRACT

Evolutionary adaptation and phenotypic plasticity are important processes on how organisms respond to pollutant exposure. We dissected here the contribution of both processes to increased tolerance in Chironomus riparius to cadmium (Cd) exposure in a multi-generation experiment and inferred the underlying genomic basis. We simulated environmentally realistic conditions by continuously increasing contaminant concentration in six replicates initiated with 1000 larvae each, three pre-exposed to Cd and three not exposed to Cd (no-Cd) over eight generations. We measured life-cycle traits, transcriptomic responses and genome-wide allele frequency changes from this evolve and resequencing (E&R) experiment. Overall, life cycle tests revealed little phenotypic adaptation to Cd exposure, but a slightly increase in survival in the first larval stage was observed. Population genomic analyses showed a strong genome-wide selective response in all replicates, highlighting two main biological functions involved in development and growth of the chironomids. Emphasizing that laboratory conditions continually exert selective pressure. However, the integration of the transcriptomic to the genomic data allowed to distinguish pathways specifically selected by the Cd exposure related to microtubules and organelles and cellular movement. Those pathways could be functionally related to an excretion of metals. Thus, our results indicate that genetic adaptation to Cd in C. riparius can happen within few generations under an environmentally relevant exposure scenario, but substantial phenotypic tolerance might take more time to arise. With our approach, we introduce an experimental setup to fill the existing gap in evolutionary ecotoxicology to investigate these early signs of genetic adaptation.


Subject(s)
Chironomidae , Water Pollutants, Chemical , Adaptation, Physiological/genetics , Animals , Cadmium/analysis , Cadmium/toxicity , Chironomidae/physiology , Larva , RNA-Seq , Water Pollutants, Chemical/analysis , Whole Genome Sequencing
9.
J Insect Physiol ; 133: 104288, 2021.
Article in English | MEDLINE | ID: mdl-34343520

ABSTRACT

Larvae of chironomid Chironomus sulfurosus mainly live in acidic rivers near hot springs, suggesting that they naturally select acidic environments as preferred habitats. Here we showed that C. sulfurosus larvae moved toward acidic areas and stayed alive on agar gels with a pH gradient of H2SO4, and the body fluid pH of the homogenized larvae was near neutral even acclimated under the acidic conditions, indicating mechanisms for acid tolerance. In order to gain insights into this mechanism at the molecular level, de novo RNA-seq analysis was performed on C. sulfurosus larvae. As a result, 1,208 genes were found to be significantly up-regulated in larvae acclimated at pH 2.0 compared to controls at pH 7.0. Among the up-regulated genes, ones encoding cuticle proteins, peritrophic matrix proteins, mucus-forming proteins, F-type ATPase subunits, glutathione S transferases, ß-1,3-D-glucan synthetase, hemoglobin, and cytochrome P450 were identified. This transcriptome analysis in conjunction with behavioral and biochemical assays expands our knowledge of gene expression in C. sulfurosus larvae living in acidic environments, which will provide a basis for further studies to elucidate the molecular mechanisms for acid tolerance employed by organisms in nature.


Subject(s)
Chironomidae/physiology , Fresh Water/chemistry , Genes, Insect , Insect Proteins/metabolism , Transcriptome , Acids/metabolism , Animals , Chironomidae/genetics , Chironomidae/growth & development , Gene Expression Profiling , Hydrogen-Ion Concentration , Larva/genetics , Larva/growth & development , Larva/physiology
10.
Sci Rep ; 11(1): 14979, 2021 07 22.
Article in English | MEDLINE | ID: mdl-34294865

ABSTRACT

Sinhuber et al. (Sci Rep 11:3773, 2021) formulated an equation of state for laboratory swarms of the non-biting midge Chironomus riparius that holds true when the swarms are driven through thermodynamic cycles by the application external perturbations. The findings are significant because they demonstrate the surprising efficacy of classical equilibrium thermodynamics for quantitatively characterizing and predicting collective behaviour in biology. Nonetheless, the equation of state obtained by Sinhuber et al. (2021) is anomalous, lacking a physical analogue, making its' interpretation problematic. Moreover, the dynamical processes underlying the thermodynamic cycling were not identified. Here I show that insect swarms are equally well represented as van der Waals gases and I attribute the possibility of thermodynamic cycling to insect swarms consisting of several overlapping sublayers. This brings about a profound change in the understanding of laboratory swarms which until now have been regarded as consisting of non-interacting individuals and lacking any internal structure. I show how the effective interactions can be attributed to the swarms' internal structure, the external perturbations and to the presence of intrinsic noise. I thereby show that intrinsic noise which is known to be crucial for the emergence of the macroscopic mechanical properties of insect swarms is also crucial for the emergence of their thermodynamic properties as encapsulated by their equation of state.


Subject(s)
Behavior, Animal/physiology , Chironomidae/physiology , Animals , Biomechanical Phenomena , Interpersonal Relations , Models, Biological , Stress, Physiological , Thermodynamics
11.
Nat Commun ; 12(1): 3700, 2021 06 17.
Article in English | MEDLINE | ID: mdl-34140471

ABSTRACT

The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent.


Subject(s)
Biota , Ecosystem , Rivers , Animals , Biodiversity , Biomass , Body Size , Chironomidae/physiology , Climate , Ephemeroptera/physiology , Insecta/physiology , Plant Leaves/chemistry , Rainforest , Rivers/chemistry , Rivers/microbiology , Rivers/parasitology , Rivers/virology , Tropical Climate , Tundra
12.
J Exp Zool A Ecol Integr Physiol ; 335(6): 572-582, 2021 07.
Article in English | MEDLINE | ID: mdl-34184831

ABSTRACT

The foraging behavior determines the diet size influencing the growth and reproduction of a predator and its prey populations. Amphipods play a key role in various aquatic ecosystems. Gammarus aequicauda is an abundant widespread omnivorous species and the only known amphipod species of hypersaline waters. Its predation can suppress the populations of planktonic and benthic invertebrates. Males of G. aequicauda actively eat chironomid larvae but there is no data on predatory females. Experiments were conducted to study sex-related differences in feeding behavior including during precopulatory mate guarding (PCMG). There were significant sex differences in feeding characteristics. For females, calculations showed that maximum consumption could be 3-4 chironomid larvae per day and for males about 9-10 larvae per day. During PCMG, males did not feed and females fed as efficiently as single females. Males transported females and alone carrying the energetic costs of swimming during PCMG. Less expenditure of energy on swimming means more energy for reproduction for females. This allows more energy-efficient use of food resources and increases the reproductive success of the population. There are currently two alternative views on PCMG among crustaceans. 1. It is a sexual conflict between males and females serving as a male adaptive strategy to achieve a female during strong male competition, while females bear many costs during the long guarding period. 2. There is also the opposite view that pairs get energetic benefits from long PCMG. Obtained data suggest that PCMG is likely to be intersexual cooperation and not intersexual conflict.


Subject(s)
Amphipoda/physiology , Chironomidae/physiology , Predatory Behavior , Sexual Behavior, Animal , Animals , Female , Larva , Male , Sex Factors
13.
Aquat Toxicol ; 235: 105822, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33823484

ABSTRACT

Unintentional environmental consequences caused by neonicotinoids reinforce the development of safer alternatives. Sulfoxaflor is considered such an alternative. However, ecological risk of sulfoxaflor remains largely unknown. Here, we investigated the acute and chronic toxicity of sulfoxaflor to a benthic invertebrate, Chironomus kiinensis. Sulfoxaflor showed lower lethality than imidacloprid to midges, with LC50 values of 84.1 (81.5-87.3), 66.3 (34.8-259), and 47.5 (29.5-306) µg/L for 96-h, 10-d, and 23-d exposures, respectively. Conversely, sulfoxaflor significantly inhibited C. kiinensis growth and emergence in chronic exposures when concentrations were above 20 µg/L. Effects on energy production were assessed through in vitro tests using mitochondria isolated from C. kiinensis. Sulfoxaflor disrupted mitochondrial state-3 respiration, meanwhile, adenosine triphosphatase (ATPase) activity and adenosine triphosphate (ATP) production were both inhibited in a dose-dependent manner. The observed mitochondrial dysfunction may be related to the decreased organismal growth and emergence, which could further influence biodiversity. Interestingly, sulfoxaflor uptake in C. kiinensis was detected even after emergence, implying its potential to be transported along food webs and among environmental compartments. This study provides thorough investigations on the toxicity of an emerging neonicotinoid alternative to Chironomidae. Data derived from the current study are useful to inform future ecological risk assessment and benefit problem-solving to the overall agriculture-environment nexus.


Subject(s)
Chironomidae/physiology , Insecticides/toxicity , Neonicotinoids/toxicity , Pyridines/toxicity , Sulfur Compounds/toxicity , Water Pollutants, Chemical/toxicity , Animals , Chironomidae/drug effects , Invertebrates/drug effects , Mitochondria , Nitro Compounds , Risk Assessment
14.
Article in English | MEDLINE | ID: mdl-33647463

ABSTRACT

Larvae of the Antarctic midge Belgica antarctica Jacobs (Diptera: Chironomidae) are highly tolerant of diverse environmental stresses, including freezing, severe desiccation, and osmotic extremes. Furthermore, dehydration confers subsequent desiccation and freeze tolerance. While a role for aquaporins-channels for water and other solutes-has been proposed in these dehydration processes, the types of aquaporins involved in dehydration-driven stress tolerance remain unknown. In the present study, we investigated expression of six aquaporins (Drip, Prip, Eglp1, Eglp2, Aqp12L, and Bib) in larvae of B. antarctica subjected to three different dehydration conditions: desiccation, cryoprotective dehydration, and osmotic dehydration. The expression of Drip and Prip was up-regulated under desiccation and cryoprotective dehydration, suggesting a role for these aquaporins in efficient water loss under these dehydration conditions. Conversely, expression of Drip and Prip was down-regulated under osmotic dehydration, suggesting that their expression is suppressed in larvae to combat dehydration. Larval water content was similarly decreased under all three dehydration conditions. Differences in responses of the aquaporins to the three forms of dehydration suggests distinct water management strategies associated with different forms of dehydration stress.


Subject(s)
Aquaporins/metabolism , Chironomidae/physiology , Dehydration/metabolism , Stress, Physiological , Animals , Antarctic Regions , Chironomidae/growth & development , Chironomidae/metabolism , Larva/metabolism , Osmosis
15.
Sci Rep ; 11(1): 3773, 2021 02 12.
Article in English | MEDLINE | ID: mdl-33580191

ABSTRACT

Collective behaviour in flocks, crowds, and swarms occurs throughout the biological world. Animal groups are generally assumed to be evolutionarily adapted to robustly achieve particular functions, so there is widespread interest in exploiting collective behaviour for bio-inspired engineering. However, this requires understanding the precise properties and function of groups, which remains a challenge. Here, we demonstrate that collective groups can be described in a thermodynamic framework. We define an appropriate set of state variables and extract an equation of state for laboratory midge swarms. We then drive swarms through "thermodynamic" cycles via external stimuli, and show that our equation of state holds throughout. Our findings demonstrate a new way of precisely quantifying the nature of collective groups and provide a cornerstone for potential future engineering design.


Subject(s)
Behavior, Animal/physiology , Mass Gatherings , Adaptation, Physiological/physiology , Animals , Biological Evolution , Chironomidae/physiology , Group Processes , Insecta , Models, Biological , Models, Theoretical , Thermodynamics
16.
Sci Rep ; 11(1): 400, 2021 01 11.
Article in English | MEDLINE | ID: mdl-33432041

ABSTRACT

The presence of microplastics (MPs) in the environment has generated global concerns. However, the explicit assessment of the effect of multiple anthropogenic activities on the existence of MPs in the freshwater system is scarcely reported. This study quantified anthropogenic activities and analyzed their relationship with MPs on a freshwater organism: the midge larvae (Diptera: Chironomidae). The study took place in an urban river and consisted of comparing the abundance and types of MPs. Our results highlight that, while industrial area was the most important variable contributing to the total MP concentration in midge larvae, residential area also influenced the concentration of microfibers in midge larvae. The impact of a residential area on the relative abundance of microfibers in each sample site was diluted by the proximity to an industrial area. In conclusion, we suggest that industrial areas are a potential source of MP pollution in river sediment, and midge larvae can be a good indicator of the MP concentrations in urban river systems. Quantifying anthropogenic activities can help discern their effects on MP concentration in a river system and promote management strategies.


Subject(s)
Biotransformation/physiology , Chironomidae/physiology , Microplastics/pharmacokinetics , Rivers , Animals , Aquatic Organisms , Chironomidae/metabolism , Cities , Environmental Monitoring , Feeding Behavior/physiology , Fresh Water , Geologic Sediments/chemistry , Geologic Sediments/parasitology , Industrial Waste , Microplastics/chemistry , Microplastics/toxicity , Rivers/chemistry , Rivers/parasitology , Taiwan , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/pharmacokinetics , Water Pollutants, Chemical/toxicity
17.
PLoS One ; 16(1): e0246060, 2021.
Article in English | MEDLINE | ID: mdl-33493219

ABSTRACT

Finding suitable habitats for specific functions such as breeding provides examples of key biotic adaptation. The adult marine midge Pontomyia oceana requires an extremely specific habitat, i.e., hard substrates above water in shallow water, to deposit fertilized eggs. We investigated how these sea surface-skimming insects accomplished this with a stringent time constraint of 1-2 h of the adult life span in the evenings. We observed that in artificial containers, midges aggregated at bright spots only if the light was not in the direction of the sea. This behavior could potentially attract midges toward the shore and away from the open water. Experiments were performed in the intertidal zone in southern Taiwan to test three hypotheses explaining such behavior: gradients of temperature and CO2, and soundscape. No differences were observed in moving directions or aggregation of midges under artificial temperature and CO2 gradients. However, midges preferred sounds at 75 Hz compared with other frequencies (all ≤300 Hz) as observed in a field experiment involving floating traps with loudspeakers. Moreover, when background noise was experimentally masked using white noise of all frequencies, midges were significantly more likely to aggregate at bright spots in the direction of the sea than in the absence of white noise. These results establish that sound is used by midges to navigate in dark seas and move toward the shore where exposed hard substrates are in abundance. Marine mammals present well-known cases of sound pollution at sea; here the finding in the insignificant marine midge is just the harbinger of the potential effects noise at shore may have to affect critical reproductive stages of marine organisms.


Subject(s)
Chironomidae/physiology , Ecosystem , Spatial Navigation/physiology , Animals , Darkness , Reproduction/physiology , Taiwan
18.
Aquat Toxicol ; 227: 105593, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32861021

ABSTRACT

Along with traditional ecotoxicological approaches in model organisms, toxicological studies in non-model organisms are being taken into consideration in order to complement them and contribute to more robust approaches. This allows us to figure out the complexity of the exposures involved in natural ecosystems. In this context, in the present research we have used the model species Chironomus riparius (Chironomidae, Diptera) and the non-model species Prodiamesa olivacea (Chironomidae, Diptera) to assess the aquatic toxic effects of acute 4-h and 24-h exposures to 1 µgL-1 of three common environmental pollutants: butyl benzyl phthalate (BBP), bisphenol A (BPA), and benzophenone 3 (BP3). Individuals of both species were collected from a contaminated river (Sar) in Galicia (Spain). Regarding Chironomus, there are four OECD standardized tests for the evaluation of water and sediment toxicity, in which different species in this genus can be used to assess classical toxicity parameters such as survival, immobilization, reproduction, and development. In contrast, Prodiamesa is rarely used in toxicity studies, even though it is an interesting toxicological species because it shares habitats with Chironomus but requires less extreme conditions (e.g., contamination) and higher oxygen levels. These different requirements are particularly interesting in assessing the different responses of both species to pollutant exposure. Quantitative real-time PCR was used to evaluate the transcriptional changes caused by xenobiotics in different genes of interest. Since information about P. olivacea in genomic databases is scarce, its transcriptome was obtained using de novo RNAseq. Genes involved in biotransformation pathways and the oxidative stress response (MnSOD, CAT, PHGPx, Cyp4g15, Cyp6a14-like and Cyp6a2-like) were de novo identified in this species. Our results show differential toxic responses depending on the species and the xenobiotic, being P. olivacea the dipteran that showed the most severe effects in most of the studied biomarker genes. This work represents a multi-species approach that allows us to deepen in the toxicity of BBP, BPA, and BP3 at the molecular level. Besides, it provides an assessment of the tolerance/sensitivity of natural populations of model and non-model insect species chronically exposed to complex mixtures of pollutants in natural scenarios. These findings may have important implications for understanding the adverse biological effects of xenobiotics on P. olivacea, providing new sensitive biomarkers of exposure to BBP, BPA, and BP3. It also highlights the suitability of Prodiamesa for ecotoxicological risk assessment, especially in aquatic ecosystems.


Subject(s)
Biomarkers/metabolism , Chironomidae/physiology , Environmental Biomarkers , Water Pollutants, Chemical/toxicity , Animals , Benzhydryl Compounds , Benzophenones , Chironomidae/drug effects , Ecosystem , Larva/drug effects , Phenols , Phthalic Acids , Rivers , Sentinel Species , Xenobiotics/metabolism
19.
Ecotoxicol Environ Saf ; 202: 110906, 2020 Oct 01.
Article in English | MEDLINE | ID: mdl-32800241

ABSTRACT

The nonsteroidal anti-inflammatory drug diclofenac (DCF) is considered a contaminant of emerging concern. DCF can co-exist with heavy metals in aquatic environments, causing unexpected risks to aquatic organisms. This study aimed to assess the combined effects of DCF and cadmium (Cd) at environmentally relevant concentrations on the bioconcentration and status of oxidative stress and detoxification in Chironomus riparius larvae. The larvae were exposed to DCF (2 and 20 µg L-1) and Cd (5 and 50 µg L-1) alone or in mixtures for 48 h. The combined exposure to DCF and Cd was found to reciprocally facilitate the accumulation of each compound in larvae compared with single exposures. As indicated by the antioxidant enzyme activities, reduced glutathione levels, and malondialdehyde contents, the low concentration of the mixture (2 µg L-1 DCF + 5 µg L-1 Cd) did not alter the oxidative stress status in larvae, while the high concentration of the mixture (20 µg L-1 DCF + 50 µg L-1 Cd) induced stronger oxidative damage to larvae compared with single exposures. The expression levels of eight genes (CuZnSOD, MnSOD, CAT, GSTd3, GSTe1, GSTs4, CYP4G, and CYP9AT2) significantly decreased due to the high concentration of the mixture compared with single exposures in most cases. Overall, the results suggest that the mixture of DCF and Cd might exert greater ecological risks to aquatic insects compared with their individual compounds.


Subject(s)
Cadmium/toxicity , Chironomidae/physiology , Diclofenac/toxicity , Water Pollutants, Chemical/toxicity , Animals , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Cadmium/metabolism , Chironomidae/drug effects , Diclofenac/metabolism , Inactivation, Metabolic/drug effects , Larva/drug effects , Malondialdehyde/metabolism , Metals, Heavy/metabolism , Oxidative Stress/drug effects , Superoxide Dismutase/metabolism , Water Pollutants, Chemical/metabolism
20.
Sci Rep ; 10(1): 11633, 2020 07 15.
Article in English | MEDLINE | ID: mdl-32669703

ABSTRACT

Larvae of the sleeping chironomid Polypedilum vanderplanki are known for their extraordinary ability to survive complete desiccation in an ametabolic state called "anhydrobiosis". The unique feature of P. vanderplanki genome is the presence of expanded gene clusters associated with anhydrobiosis. While several such clusters represent orthologues of known genes, there is a distinct set of genes unique for P. vanderplanki. These include Lea-Island-Located (LIL) genes with no known orthologues except two of LEA genes of P. vanderplanki, PvLea1 and PvLea3. However, PvLIL proteins lack typical features of LEA such as the state of intrinsic disorder, hydrophilicity and characteristic LEA_4 motif. They possess four to five transmembrane domains each and we confirmed membrane targeting for three PvLILs. Conserved amino acids in PvLIL are located in transmembrane domains or nearby. PvLEA1 and PvLEA3 proteins are chimeras combining LEA-like parts and transmembrane domains, shared with PvLIL proteins. We have found that PvLil genes are highly upregulated during anhydrobiosis induction both in larvae of P. vanderplanki and P. vanderplanki-derived cultured cell line, Pv11. Thus, PvLil are a new intriguing group of genes that are likely to be associated with anhydrobiosis due to their common origin with some LEA genes and their induction during anhydrobiosis.


Subject(s)
Cell Membrane/metabolism , Chironomidae/physiology , Dehydration , Insect Proteins/metabolism , Membrane Proteins/metabolism , Amino Acid Motifs , Animals , Cell Line , Cloning, Molecular , Cluster Analysis , Computer Simulation , Gene Expression Profiling , Gene Expression Regulation , Larva/physiology , Multigene Family , Phylogeny , Protein Domains , RNA-Seq
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