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Martínez Guitarte, José Luis

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Martínez Guitarte
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Mostrando 1 - 5 de 5
  • Publicación
    Chironomus riparius molecular response to polystyrene primary microplastics
    (ELSEVIER, 0023-04-10) Kalman, Judit; Muñiz González, Ana Belén; García, María Ángeles; Martínez Guitarte, José Luis
    Microplastics are emerging as a central concern for the environment. They can be found worldwide, produced for the industry and because of plastic debris degradation. The microplastics are smaller than 5 mm, but they can also range in micro and nanometer scales, present in soil and aquatic ecosystems. Furthermore, they can have different chemical compositions, including additives with putative toxicity. Chironomus riparius is a dipteran with aquatic larvae used in toxicology tests. As a benthic organism, it can be exposed to microplastics in the water and the sediments, being able to ingest some of them depending on the size and shape. However, it is still poor knowledge of the effects that microplastics have on invertebrates, especially at the molecular level. We have analyzed the impact that 5–5.9 μm spheres of polystyrene have on the metabolism of C. riparius, studying the transcriptional activity of eighty genes, twenty-eight described here for the first time. The genes covered the endocrine response, the detoxification mechanisms, the stress response, the DNA repairing mechanisms, hypoxia, oxidative stress, apoptosis, immunity, cholesterol metabolism, energy metabolism, the circadian rhythm, signaling, and regulation of piRNAs. The results showed that at 24 h, the stress response was the most affected, while at 48 h, the endocrine response and detoxification were slightly affected. Finally, at 72 h, endocrine response, detoxification mechanisms, and lipid metabolism genes were altered. Overall, the data suggest an acute response involving stress genes downregulation, while the later response seems to move to metabolic alterations, with changes in hormonal regulation and metabolism. It could be because micrometer microplastics are confounded with food, decreasing the availability of resources for larval development. The present work shows a dynamic impact of polystyrene microspheres and provides new putative biomarkers to analyze several mechanisms involved in the cellular and physiological response to toxicants.
  • Publicación
    Effects of wildfire ashes on aquatic invertebrates: First molecular approach on Chironomus riparius larvae
    (Elsevier, 2022-11-03) Muñiz González, Ana Belén; Campos, Isabel; Re, Ana; Martínez Guitarte, José Luis; Nelson Abrantes
    The wildfire magnification in recent years has raised increasing concern about their adverse impacts on the environment. Wildfires are recognized as an important source of diffuse pollution for the nearby aquatic systems being potentially toxic to aquatic life. Albeit previous studies with wildfire runoff/ashes observed effects in aquatic organisms, to date, different severity origins of ashes and their impact at the sub-organismal level on aquatic biota have not been assessed. In this work, the molecular response of Chironomus riparius exposed to wildfire with low (LS) and high (HS) severity ashes from burnt Pine plantations was evaluated by employing an array of 42 genes related to crucial metabolic pathways by Real time-PCR. IV instar larvae were exposed for 72 h to aqueous extract of ashes (12.5 %, 25 %, 50 %, 75 % and 100 %) prepared from LS and HS ashes. Mn, Zn, and Pb were the metals found at highest concentration in both ash extracts, for HS notable Cd, Mn and Cr presence. From the 42 genes studied only 4 were not altered (22 genes modulated their response by LS and 38 genes in the case of HS) showing the opposite response at 100% with downregulated by LS and upregulated by HS. The 12.5 %, 25 %, 100 % HS and 25 % LS were the main modulators, confirmed by the integrative biomarkers response (IBR). Remarkable genotoxicity was generated by ashes even activating the apoptosis response, and endocrine disruption observed could modify the development. Moreover, detoxification and stress response were strongly activated, limiting the organism's future response to external aggressions. The employment of this novelty approach with molecular tools act as early alarm signal preventing greater damages. Overall, wildfire ashes showed to be a significant environmental disruptor to C. riparius even at lower concentration and the short exposure time employed, emphasizing the strong impact of wildfires on aquatic systems.
  • Publicación
    Molecular biomarkers as tool for early warning by chlorpyrifos exposure on Alpine chironomids
    (Elsevier, 2021-08-26) Muñiz González, Ana Belén; Paoli, Francesca; Martínez Guitarte, José Luis; Lencioni, Valeria
    Pesticides used in agriculture can be transported at a medium-high distance due to the drift effect, reaching even remote areas as mountain regions, glaciers, and snow cover. With the melting process, pesticides enter freshwater glacier ecosystems, becoming a threat to wildlife fauna, mainly dominated by Diptera Chironomidae. Chlorpyrifos (CPF), as one of the most commonly used pesticides in alpine vineyards and apple orchards, is frequently detected in icemelt waters. We selected as target species, larvae of the cold stenothermal chironomid Diamesa zernyi, collected in two glacier-fed streams (Presena and Amola) in the Italian Alps. Firstly, a de novo transcriptome was obtained, and secondly, a gene array was designed to study the molecular response of a wild population of D. zernyi exposed to three sub-lethal CPF concentrations corresponding to 1/100 LC10 (0.011 μg/ L), 1/10 LC10 (0.11 μg/L), and LC10 (1.1 μg/L), for 24 h. The sub-organismal response was evaluated by Real-Time Polymerase Chain Reaction (RT-PCR), employing 40 genes related to essential metabolic routes as future candidates for biomarkers in wildlife chironomids. After 24 h, the endocrine system (E75, E93, EcR, and Met), detoxification response (GSTO3, GSTS1), and stress response (hsp75, hsp83, HYOU1) were altered. CPF seems to act as an endocrine disruptor and could lead to defective larval development, disrupted cellular homeostasis through heat shock proteins (HSPs) alteration (defective protein folding and mitochondrial functions), as well as oxidative damage (confirmed by increased GST expression). For the first time, molecular studies detected early alarm signals in wildlife in glacier environments. Our findings confirm the high environmental risk of CPF affecting aquatic insect metabolism and raise the level of concern about this pesticide in high altitude water bodies, generally considered pristine. Furthermore, this study emphasizes the incipient need to use non-model organisms for the evaluation of natural ecosystems. We also highlight the demand for research into new molecular biomarkers, and the importance of including molecular approaches in toxicology evaluations to detect the early adverse effects of pollutants.
  • Publicación
    Suborganismal responses of the aquatic midge Chironomus riparius to polyethylene microplastics
    (Elsevier, 2021-08-20) Muñiz González, Ana Belén; Silva, Carlos J.M.; Patricio Silva, Ana L.; Campos, Diana; Pestana, João L.T.; Martínez Guitarte, José Luis
    Freshwater riverbeds are a major repository of microplastics (MPs) from inland activities. Benthic macroinvertebrates that live in close contact with sediments seem to ingest a considerable amount of such plastic particles. The effects of MPs on life-history traits are relatively well-known, but the suborganismal mechanisms underlying such effects remain unclear. This study addressed the potential effects of low-density polyethylene (LDPE) MPs Freshwater riverbeds are a major repository of microplastics (MPs) from inland activities. Benthic macroinvertebrates that live in close contact with sediments seem to ingest a considerable amount of such plastic particles. The effects of MPs on life-history traits are relatively well-known, but the suborganismal mechanisms underlying such effects remain unclear. This study addressed the potential effects of low-density polyethylene (LDPE) MPs on Chironomus riparius larvae at cellular and molecular levels. Fourth instar C. riparius larvae were exposed to 0.025 and 2.5 g/kg LDPE of dry sediment (sizes: <32 and 32–45 μm; with irregular shape) under laboratory conditions for 48 h. These short-term exposures to environmental concentrations of LDPE MPs induced changes in the energy reserves (mostly by decreasing carbohydrates and increasing lipids), increased antioxidant and detoxification responses (tGSH, CAT, and GST), and induced increases in the activity of AChE (related to neurotransmission). In addition, at the gene level, exposure to MPs modified mRNA levels of InR, Dis, EcR, Dronc, Met (endocrine system), Def (immune system), PARP, ATM, NLK, and Decay (DNA repair), generating important alterations in the C. riparius development and response to unfavorable situations. This study provides new evidence of the effects of LDPE MPs at the suborganismal level, filling the gap in knowledge regarding the mechanisms underlying the toxicity of MPs and spotlighting gene expression analyses as early indicators of MP toxicity in C. riparius which were confirmed by Integrated biomarker response analyses highlighting the gene expression as sensible and useful endpoints for LPDE pollution in freshwaters. These results, coupled with previous investigations on responses at the organismal level, emphasizes the potential adverse effects of LDPE MPs on C. riparius, which may compromise freshwater benthic communities, considering its ecological role within these habitats. on Chironomus riparius larvae at cellular and molecular levels. Fourth instar C. riparius larvae were exposed to 0.025 and 2.5 g/kg LDPE of dry sediment (sizes: <32 and 32–45 μm; with irregular shape) under laboratory conditions for 48 h. These short-term exposures to environmental concentrations of LDPE MPs induced changes in the energy reserves (mostly by decreasing carbohydrates and increasing lipids), increased antioxidant and detoxification responses (tGSH, CAT, and GST), and induced increases in the activity of AChE (related to neurotrans-mission). In addition, at the gene level, exposure to MPs modified mRNA levels of InR, Dis, EcR, Dronc, Met (endocrine system), Def (immune system), PARP, ATM, NLK, and Decay (DNA repair), generating important alterations in the C. riparius development and response to unfavorable situations. This study provides new evidence of the effects of LDPE MPs at the suborganismal level, filling the gap in knowledge regarding the mechanisms underlying the toxicity of MPs and spotlighting gene expression analyses as early indicators of MP toxicity in C. riparius which were confirmed by Integrated biomarker response analyses highlighting the gene expression as sensible and useful endpoints for LPDE pollution in freshwaters. These results, coupled with previous investigations on responses at the organismal level, emphasizes the potential adverse effects of LDPE MPs on C. riparius, which may compromise freshwater benthic communities, considering its ecological role within these habitats.
  • Publicación
    Environmentally Relevant Concentrations of the Insecticide Fipronil Modulated Molecular Response in Chironomus riparius
    (Wiley, 2023-11-29) da Silva Pinto, Thandy Junio; Martínez Guitarte, José Luis; Dias, Mariana Amaral; Montagner, Cassiana Carolina; Gaeta Espindola, Evaldo Luiz; Muñiz González, Ana Belén
    Pesticides employed worldwide for crop protection easily reach aquatic systems, which act as the main reservoirs, and become a risk factor for aquatic fauna. Fipronil is a broad‐spectrum insecticide acting on the insect nervous system; however, other effects and systems unrelated to this mechanism could be affected in non‐target organisms. Thus, the present study aimed to assess the impact of fipronil on the suborganismal response (gene expression and enzymatic activity) of Chironomus riparius larvae as a model organism in ecotoxicology. To this end, short‐term toxicity tests were carried out with fourth‐instar larvae exposed to 0.001, 0.01, and 0.1 μg L−1 of fipronil for 24 and 96 h. Messenger RNA levels of 42 genes related to diverse metabolic pathways were analyzed by real‐time polymerase chain reaction, complemented with catalase (CAT), glutathione S‐transferase (GST), and acetylcholinesterase (AChE) activities. Few effects were observed at 24 h; however, after longer exposure (96 h), genes involved in the endocrine, detoxification, stress, and immune response pathways were altered. Moreover, fipronil at 96 h increased CAT and GST activity at 0.01 μg L−1 and AChE at the highest concentrations. The results demonstrate that even low environmentally relevant fipronil concentrations can modulate the molecular response of several cellular pathways in C. riparius after short‐term exposure. These results bring new information about the underlying response of fipronil and its mode of action on a key aquatic invertebrate. Despite no effects on mortality, strong modulation at the suborganismal level emphasizes the advantage of biomarkers as early damage responses and the harmful impact of this pesticide on freshwater organisms. Environ Toxicol Chem 2024;43:405–417. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.