Search Results (53)

(1) Background: Aquatic organisms are more sensitive to pollutants than terrestrial ones, making them ideal for ecotoxicology studies. Chironomids, a key bioindicator species, have been widely used in environmental pollution research. With the continuous deepening of research on water environmental pollution and the continuous development of molecular biology, it is therefore very important to understand the current research progress of the toxicology of chironomids. (2) Methods: This study used bibliometrics to analyze 1465 publications on chironomid toxicology from the Web of Science and PubMed databases, aiming to reveal research trends, hotspots, and future directions. The data analysis involved Microsoft Excel, VOS viewer, CiteSpace, and ChatGLM. (3) Results: Heavy metals, pesticides, and microplastics were the main pollutants studied, with Chironomus riparius being the most researched species. The analysis indicated a growing research trend since 1998, reflecting an increasing global concern over aquatic pollution. This study concludes that more molecular-level research is needed to uncover toxic mechanisms and improve environmental risk assessments. (4) Conclusions: This work will aid scientists and policymakers in developing better pollution control strategies and conservation efforts for aquatic ecosystems, ultimately contributing to environmental protection and public health. Full article

Insect mitochondrial genomes are vital to understanding evolutionary relationships and identifying species. This study focused on Microtendipes (Chironomidae), a genus with unresolved phylogenetic positioning and cryptic species challenges. We sequenced and analyzed eight mitogenomes from five Microtendipes species, integrating 23 published Chironominae mitogenomes to reconstruct phylogenies using Maximum Likelihood and Bayesian Inference. The mitogenomes exhibited conserved gene arrangements but variable control region lengths (338–1266 bp) and high AT content (94.14–96.42% in control regions). Our results show that Microtendipes species may be a separate group within the subfamily, while also supporting the monophyly of the Harnischia, Polypedilum, and Chironomus complexes. The monophyly of Microtendipes bimaculus was weakly supported, which may demonstrate the presence of two potential cryptic species. Notably, larval morphology-based species groupings conflicted with the molecular data, suggesting that classifications derived from larval morphological traits may be unreliable. This study advances the evolutionary understanding of Chironomidae and underscores the limitations of single-gene barcodes in species-rich genera. Full article

This study evaluates the effects of caffeine (CAF) on the bacteria Aliivibrio fischeri, the microalga Raphidocelis subcapitata, the macrophyte Lemna minor, and the larvae of Chironomus riparius, aiming to understand its environmental impact and contribution to ecological risk assessment. Bioluminescence inhibition in A. fischeri (EC₅₀ = 998.5 mg/L) and growth inhibition in R. subcapitata and L. minor (EC₅₀ = 60.1 mg/L and EC₅₀ = 649.2 mg/L, respectively) were observed. For L. minor, reduced catalase (CAT) activity and non-linear responses in glutathione S-transferases (GSTs) were recorded. No significant changes were observed in proline, malondialdehyde (MDA), and pigment contents. In C. riparius, acute mortality (LC₅₀ = 644.5 mg/L) was observed, and growth was significantly affected after 10 days of CAF exposure (EC₅₀ = 81.62 mg/L for fresh biomass). After 10 days of exposure, there was an increase in CAT activity and thiobarbituric acid reactive substances, with TBARS levels both at concentrations ≥82.64 mg/L, and a decrease in GSTs (92.18 mg/L) and acetylcholinesterase (AChE) (≤62.09 mg/L) activities of C. riparius. The results show that CAF exposure affects organisms’ metabolic and physiological functions, with varying sensitivities among species, potentially leading to ecological disturbances in aquatic ecosystems. The hazardous concentration for 5% of species was 4.42 mg/L. Long-term studies are necessary to understand the risk of caffeine under more realistic scenarios. Full article

This study, using Hyalella azteca and Chironomus riparius, evaluated the effects of exposure to heavy metal-contaminated sediments collected from the study area under three conditions: before remediation, after remediation, and suspended particulate matter (SPM). The selected toxicity tests allowed for the evaluation of biological responses across varying concentrations of heavy metals. Statistical analysis revealed no significant differences in survival or growth between sediment-exposed organisms and controls for either species. In addition, bioaccumulation of Cr, Ni, Cu, Zn, As, Cd, and Pb in both organisms was assessed and compared among the sediment conditions and the control. No statistically significant differences in tissue metal concentrations were found between organisms exposed to sediments from the study area and those in control conditions. Sequential extraction analysis indicated that a substantial proportion of metals in the sediments were bound in stable, non-bioavailable forms. These findings are consistent with the observed biological responses, as low levels of bioavailable metals corresponded with the absence of toxic effects. Together, the data confirm that the sediments, regardless of remediation stage or particle fraction, posed no significant biological risk under the conditions tested. Full article

Bis(4-hydroxyphenyl) methane (BPF), as a bisphenolic compound, has toxic effects on organisms such as endocrine disruption and immobilization of growth and development. This study evaluated the effect concentrations of BPF on Chironomus tentans and investigated the impact of BPF exposure at various sub-lethal concentrations on the growth, development, and reproductive capacity of different instars of C. tentans. The results demonstrated that exposure at concentrations of 2.0, 2.5, 3.0, and 4.0 mg·L⁻¹ delayed pupation, inhibited the development of imaginal discs, and caused an initial rise followed by a decline in the expression levels of genes related to larval development (ecr, usp, e74). Additionally, exposure at concentrations of 1.0, 1.5, and 2.0 mg·L⁻¹ led to fluctuations in the expression levels of genes related to adult development and reproduction (ecr, kr-h1, foxo, inr, pdk, akt, and vg) in both female and male adults, with varying degrees of effect. Furthermore, BPF exposure inhibited male fertility, causing significant damage to the gonadal tissues, though it did not affect the final hatching of eggs. These findings indicate that BPF exhibits developmental and reproductive toxicity in C. tentans, with 2.0 mg·L⁻¹ identified as the lowest effective concentration at which BPF affects pupation in midges. Full article

The Harnischia generic complex, a significant assemblage within the tribe Chi-ronomini, extensive global sampling and the integration of multi-characteristic data for comprehensive analysis are essential to elucidate the phylogenetic relationships within the Harnischia generic complex. We sequenced, assembled, and annotated the mitochondrial genomes of a single species each from the genera Parachironomus Lenz, Robackia Saether and Saetheria Jackson. Additionally, we incorporated 26 previously published mitogenomes into our analysis to delve deeper into the characteristics of these mitogenomes. Our findings indicate the close affinity between (Cryptochironomus + Demicryptochironomus) and (Harnischia + Microchironomus), aligning consistently with previous research outcomes showing that the Harnischia generic complex and Chironomus are phylogenetically close, and their clade forms a sister group with the Polypedilum generic complex. Based on mitochondrial genome data, Robackia is identified as the basal taxon being relatively primitive, with Parachironomus and Saetheria also appearing as primitive within the complex. Full article

Background: Curcuminoids, the bioactive compounds found in turmeric, exhibit potent antioxidant, anti-inflammatory, and neuroprotective properties. This study aims to enhance the extraction of curcuminoids from turmeric using environmentally friendly solvents supercritical CO₂ (scCO₂) combined with natural deep eutectic solvents (NADESs) in one process, and to evaluate the resulting biological activity. Methods: A Box–Behnken statistical design was applied to optimize scCO₂ extraction conditions—pressure, CO₂ volume, and temperature—to maximize curcuminoid yield. Next, the menthol and lactic acid NADESs were selected, and these two solvents were combined into a single turmeric extraction process. The biological activity of the resulting extract was evaluated using antioxidant assays (ferric reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl) and enzyme inhibition assays (acetylcholinesterase, butyrylcholinesterase, and tyrosinase). Toxicity assessments were conducted on the aquatic invertebrates Daphnia pulex, Artemia sp., and Chironomus aprilinus. Results: The most effective extraction was achieved using a menthol–lactic acid NADES as a cosolvent, integrated at a 1:20 ratio of plant material to NADESs while in combination with scCO₂. The optimized scCO₂–NADES extraction resulted in a high curcuminoid yield (33.35 mg/g), outperforming scCO₂ extraction (234.3 μg/g), NADESs ultrasound-assisted extraction (30.50 mg/g), and alcohol-based solvents (22.95–26.42 mg/g). In biological assays, the extract demonstrated significant antioxidant activity and effective inhibition of enzymes (acetylcholinesterase, butyrylcholinesterase, and tyrosinase). Toxicity studies showed a concentration-dependent response, with EC₅₀ for Chironomus aprilinus at the level of 0.098 μL/mL and Daphnia pulex exhibiting high sensitivity to the extract. Conclusions: This study highlights the potential of combining NADESs and scCO₂ extraction in one process, demonstrating the effectiveness of scCO₂–NADES extraction in maximizing curcuminoid yield and enhancing bioactivity. Full article

Over the last few years, there has been much effort put into the development and validation of stochastic models of the trajectories of swarming insects. These models typically assume that the positions and velocities of swarming insects can be represented by continuous jointly Markovian processes. These models are first-order autoregressive processes. In more sophisticated models, second-order autoregressive processes, the positions, velocities, and accelerations of swarming insects are collectively Markovian. Although it is mathematically conceivable that this hierarchy of stochastic models could be extended to higher orders, here I show that such a procedure would not be well-based biologically because some terms in these models represent processes that have the potential to destabilize insect flight dynamics. This prediction is supported by an analysis of pre-existing data for laboratory swarms of the non-biting midge Chironomus riparius. I suggest that the Reynolds number is a finely tuned property of swarming, as swarms may disintegrate at both sufficiently low and sufficiently high Reynolds numbers. Full article

Chironomids have a number of characteristics that make them a useful group for investigating the impact of environmental and chemical stressors on their life cycle stages. It is crucial to first understand sensitivities to environmental factors and provide a basis for interpreting the results of toxicity tests. We focused on Chironomus riparius–one of the most studied species in aquatic toxicity tests—to understand the changes during the larval stage under conditions of food abundance and limitation. We developed a model based on Dynamic Energy Budget (DEB) theory, a framework to capture the entire life cycle of an individual under varying food and temperature conditions. Available information from this study and the literature pointed out that the first three larval instars are immature and the fourth larval instar is mature, during which the organism saves, in two phases, energy for essential processes occurring during the subsequent non-feeding stages. The model can successfully predict the observed prolonged fourth instar duration under food limitation, the times of life history events (e.g., pupation and emergence), and egg production. This model has the potential to be integrated with toxicokinetic–toxicodynamic models to study the effects of toxicants on a variety of biological traits. Full article

In the packaging materials sector, increasing globalization has created the need for increased efforts to develop consumer protection measures. Consequently, new packaging materials are being sought to replace petroleum-based materials in the future. For this reason, global awareness of the environmental problems associated with the use of synthetic and non-degradable packaging has increased the attention paid to bio-packaging based on natural and biodegradable polymers. The bio-packaging sector is developing innovations to address the sustainability issues facing the food packaging industry. Our research has shown that green matcha extract can be a promising source of antioxidants for the production of bioactive pectin films. This study further confirmed that green matcha extract can be a promising source of antioxidants for the production of bioactive pectin films. The antioxidant activity test showed high activity of films containing matcha extract. The antioxidant activity of films without matcha addition, P, PJ, PC, PJC, was negligible. The addition of matcha to the polymer matrix did not significantly affect the mechanical properties (TS, EB) of the films obtained. The addition of cellulose had the greatest effect on changing the mechanical properties. It caused a twofold increase in the mechanical properties of the obtained packaging films. The addition of matcha significantly improved the barrier properties (for PM films, the WVTR was 3.40 [g/m²d]; for PJM films the WVTR was 1.70 [g/m²d]). The green packaging films showed no toxic effects on the plants (Phacelia tanacetifolia, Salvia hispanica, Brassica napus) and invertebrates (Daphnia pulex, Chaoborus, Chironomus aprilinus) tested. The half-solubility time of the membranes in a solution mimicking gastric acid was also determined. The longest half-dissolution time of the films was about 2 min. Our research has therefore shown that the biodegradable and environmentally safe green packaging films with antioxidant activity that we have developed can be used as edible functional casings in the future, e.g., for sausages and other food products. Full article

Against the backdrop of hydropower development in the upper Yellow River, comprehending the spatiotemporal variation and ecological evaluation of macroinvertebrate functional feeding groups (FFGs) is paramount for the conservation and restoration of aquatic biological resources in watersheds. Detailed surveys of macroinvertebrates were conducted in the gorge and plain areas of the upper Yellow River in July 2022 and March, May, and October 2023, culminating in the identification of 65 taxonomic units (genus or species) spanning 4 phyla, 14 orders, and 35 families. Of these, 41 taxonomic units were discovered in the gorge areas and 57 in the plain areas. Among the FFGs of macroinvertebrates in the upper Yellow River, collector-gatherers were overwhelmingly dominant, followed by scrapers, collector-filterers, predators, and shredders. Concerning river section types, dominant species in the gorge areas included Gammarus sp., Limnodrilus hoffmeisteri, and Polypedilum sp. among collector-gatherers, while in the plain areas, dominant species included Ecdyonurus sp. among scrapers, Hydropsyche sp. among collector-filterers, and Gammarus sp., Limnodrilus hoffmeisteri, and Chironomus sp. among collector-gatherers. A Mantel test revealed that dissolved oxygen, conductivity, and orthophosphate were the primary environmental factors affecting the FFGs of macroinvertebrates in the upper Yellow River, with variations observed in their effects across different months. The evaluation results of the Hilsenhoff Biological Index and Shannon–Wiener Index indicate that the water quality of the upper Yellow River is at a moderate level. An assessment of the upper Yellow River ecosystem using FFG parameters demonstrated that macroinvertebrate biomass progressively increased from upstream (gorge areas) to downstream (plain areas) spatially, accompanied by increasing habitat stability, with cascade hydropower development identified as a key factor impacting habitat stability. These findings provide pertinent data and a theoretical foundation for the protection of aquatic biological resources and watershed management in the upper Yellow River. Full article

Typical in silico models for ecotoxicology focus on a few endpoints, but there is a need to increase the diversity of these models. This study proposes models using the NOEC for the harlequin fly (Chironomus riparius) and EC50 for swollen duckweed (Lemna gibba) for the first time. The data were derived from the EFSA OpenFoodTox database. The models were based on the correlation weights of molecular features used to calculate the 2D descriptor in CORAL software. The Monte Carlo method was used to calculate the correlation weights of the algorithms. The determination coefficients of the best models for the external validation set were 0.74 (NOAEC) and 0.85 (EC50). Full article

The Toce River (Northern Italy) is characterized by legacy contamination of dichloro-diphenyl-trichloroethane (DDT), mercury, and arsenic deriving from an industrial plant active between ca. 1915 and 1996. Chironomidae taxa assemblages and sediments were collected in 2014 and 2019 upstream and downstream of the industrial area to analyze species responses to toxic substances in a river stretch with relatively uniform natural (i.e., hydro-morphological) characteristics. A total of 32 chironomid taxa were identified. Sediment concentrations reached levels potentially toxic for benthic invertebrates: 15.7 µg kg⁻¹ 1% organic carbon for DDT, 197 µg kg⁻¹ dry weight (d.w.) for Hg, and 55.7 mg kg⁻¹ d.w. for As. Canonical Correspondence Analysis (CCA) revealed a predominant seasonal gradient, followed by an upstream-downstream gradient. Partial CCA indicated that 5.2% of the total variation was associated with sediment contamination. Self-Organizing Maps (SOMs) were used to represent species responses to toxicants. Most species appeared to be tolerant, e.g., Chironomus riparius, Micropsectra atrofasciata, Conchapelopia pallidula, and Polypedilum spp. Sensitivity to contaminants was observed in only a few species: Diamesa spp., Sympotthastia spinifera, and Prodiamesa olivacea to DDT; Potthastia longimanus to Hg; Odontomesa fulva and Microtendipes pedellus to As. The chironomid community was characterized in presence of contamination levels commonly observed in freshwater ecosystems. Full article

Plenty of freshwater species, especially macroinvertebrates that are essential to the provision of numerous ecosystem functions, encounter higher mortality due to acute hypoxia. However, within the family Chironomidae, a wide range of tolerance to hypoxia/anoxia is displayed. Propsilocerus akamusi depends on this great tolerance to become a dominant species in eutrophic lakes. To further understand how P. akamusi responds to acute hypoxic stress, we used multi-omics analysis in combination with histomorphological characteristics and physiological indicators. Thus, we set up two groups—a control group (DO 8.4 mg/L) and a hypoxic group (DO 0.39 mg/L)—to evaluate enzyme activity and the transcriptome, metabolome, and histomorphological characteristics. With blue–black chromatin, cell tightness, cell membrane invagination, and the production of apoptotic vesicles, tissue cells displayed typical apoptotic features in the hypoxic group. Although lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH), catalase (CAT), and Na+/K+ -ATPase (NKA) activities were dramatically enhanced under hypoxic stress, glycogen content, and superoxide dismutase (SOD) activities were significantly reduced compared to the control group. The combined analysis of the transcriptome and metabolome, which further demonstrated, in addition to carbohydrates, including glycogen, the involvement of energy metabolism pathways, including fatty acid, protein, trehalose, and glyoxylate cycles, provided additional support for the aforementioned findings. Lactate is the end product of glycogen degradation, and HIF-1 plays an important role in promoting glycogenolysis in acute hypoxic conditions. However, we discovered that the ethanol tested under hypoxic stress likely originates from the symbiodinium of P. akamusi. These results imply that some parameters related to energy metabolism, antioxidant enzyme activities, and histomorphological features may be used as biomarkers of eutrophic lakes in Chironomus riparius larvae. The study also provides a scientific reference for assessing toxicity and favoring policies to reduce their impact on the environment. Full article