Especies reactivas de oxígeno y su implicación en Biomedicina

Reactive oxygen species (ROS) act as intracellular regulator when they are generated under control in specific cell spots. They modify proteins function by cysteine reversible oxidation. There are protein kinases and phosphatases, transcription factors and ionic channels that are regulated by ROS. Oxidative stress and cell damage arise when the protection antioxidant mechanisms are unable to keep low the intracellular ROS level. Under these conditions, ROS induce cell viability loss in heart and brain degenerative pathologies and promote unlimited cell proliferation in tumor processes. Alteration of the mitochondrial function is a key player in the oxidative stress generation and therefore it is preferential therapeutic target for prevention or attenuation of the ROS-induced oxidative damage.Las especies reactivas de oxígeno (ROS) actúan como regulador intracelular cuando se generan de forma controlada en puntos concretos de la célula. Modifican la función de proteínas mediante la oxidación reversible de cisteínas. Hay quinasas y fosfatasas de proteínas, factores de transcripción y canales iónicos que están regulados por ROS. Estrés oxidativo y daño celular aparecen cuando los mecanismos antioxidantes de protección son incapaces de mantener bajo el nivel intracelular de ROS. En estas condiciones, ROS inducen pérdida de viabilidad celular en patologías degenerativas de corazón y cerebro y promueven proliferación celular ilimitada en procesos tumorales. La alteración de la función mitocondrial juega un papel clave en la generación del estrés oxidativo y por tanto es una diana terapéutica preferente para evitar o aminorar los daños oxidativos producidos por ROS

Co, Zn and Ag-MOFs evaluation as biocidal materials towards photosynthetic organisms

In the present study, the biocidal activity of three different metal organic frameworks (MOFs) based on Co (Co-SIM1), Zn (Zn-SIM1) and Ag (Ag-TAZ) has been evaluated towards one green alga and two cyanobacteria. These organisms are present in fresh- and seawater and take part in the early stages of the biofouling process. The biocidal activity of these materials was evaluated by measuring chlorophyll a concentration and by inhibition zone testing. After 24 h of exposure the three different MOFs caused > 50% of chlorophyll a concentration inhibition towards both cyanobacteria, however, although the green alga presented a great sensitivity for Ag-TAZ (reaching 90% of chlorophyll a concentration inhibition), it was much more resistant to the rest of MOFs. Bioavailability of these metals was studied using ICP-MS, the chemical speciation program Visual MINTEQ, and a heavy metal bioreporter bioanalytical tool. We have elucidated that the biocidal activity presented by these MOFs was due to the dissolved metals released from them and more exactly, it depended on the bioavailability presented by these metal ions, which was closely related with the free ion concentration. This article highlights the potential use of different MOFs as biocidal material towards photosynthetic organisms and reveals important differences in the sensitivity between these organisms that should be taken into account in order to increase the biocidal spectrum of these materialsThis research was supported by the Spanish Ministry of Economy, CTM2013-45775-C2-1-R and CTM2013-45775-C2-2-

Secondary nanoplastics released from a biodegradable microplastic severely impact freshwater environments

This article is part of the themed collection: Environmental Science: Nano Recent HOT Articles https://pubs.rsc.org/en/journals/articlecollectionlanding?sercode=en&themeid=280a8 9ca-3eed-4abe-ae65-c856206f6c3c Article selected by the Editors in Chief of Environmental Science journals: DOI: 10.1039/D0EM90014A (Editorial)Over the last five decades, plastics production has increased as a consequence of their use in strategic sectors causing damage on aquatic ecosystems. In this context, biodegradable plastics have emerged as an ecological alternative because they are easily degradable in the environment. Despite the recent advances in the field of plastic ecotoxicology, the ecological impact of secondary nanoplastics (nanoplastics resulting from natural degradation of micro and macro plastics) in the environment remains poorly understood. Here, we have investigated the effects of secondary nanoplastics of polyhydroxybutyrate (PHB), a biodegradable plastic, on three representative organisms of aquatic ecosystems. Secondary PHB-nanoplastics were produced from PHB-microplastics by abiotic degradation under environmentally representative conditions. Secondary PHB-nanoplastics induced a significant decrease in cellular growth and altered relevant physiological parameters in all organisms. We investigated whether the observed toxicity was exerted by PHB-nanoplastics themselves or by other abiotic degradation products released from PHB-microplastics. An experiment was run in which PHB-nanoplastics were removed by ultrafiltration; the resulting supernatant was not toxic to the organisms, ruling out the presence of toxic chemicals in the PHB-microplastics. In addition, we have performed a complete physicochemical characterization confirming the presence of secondary PHB-nanoplastics in the 75-200 nm range. All results put together indicated that secondary PHB-nanoplastics released as a consequence of abiotic degradation of PHB-microplastics were harmful for the tested organisms, suggesting that biodegradable plastic does not mean safe for the environment in the case of PH

Microplastics in sediments of artificially recharged lagoons: case study in a Biosphere Reserve

We studied the occurrence of microplastics in sediments of artificially and non-artificially recharged lagoons from the network of endorheic wetlands called “La Mancha Húmeda”, declared Biosphere Reserve by UNESCO. The particles sampled in this study covered the 25 μm–5 mm range. Films were the dominant microplastic typology in non-artificially recharged lagoons, while fibres and fragments were more abundant in those receiving wastewater. The concentration of microplastics in sediments reached up to 24.4 ± 5.2 microplastics/g, while plastic litter counts yielded <1 particle/g in non-wastewater receiving lagoons. Eleven types of plastic were identified using Micro-Fourier Transform Infrared Spectroscopy (micro-FTIR), the most abundant being the polyolefins polyethylene and polypropylene, and polyester and acrylic fibres. The statistical analysis of FTIR spectra confirmed the similarity between samples taken from recharged lagoons and wastewater treatment plant effluents. Overall, our results showed that endorheic lagoons are very sensitive to the accumulation of persistent pollutants, which include microplastics. The recharge of lagoons with wastewater effluents to maintain water levels, even if correctly treated according to current standards, is not a sustainable practice. Due to the closed character of endorheic basins, the continuous input of wastewater led to the accumulation of microplastics in sediments of wastewater receiving lagoons up to 40 times over non-recharged lagoon

Optimization of a Line detection algorithm for autonomous vehicles on a RISC-V with accelerator

In recent years, autonomous vehicles have attracted the attention of many research groups, both in academia and business, including researchers from leading companies such as Google, Uber and Tesla. This type of vehicles are equipped with systems that are subject to very strict requirements, essentially aimed at performing safe operations -both for potential passengers and pedestrians- as well as carrying out the processing needed for decision making in real time. In many instances, general-purpose processors alone cannot ensure that these safety, reliability and real-time requirements are met, so it is common to implement paper explores the acceleration of a line detection aprunning without accelerator

Microplastics in sediments of artificially recharged lagoons: Case study in a Biosphere Reserve

We studied the occurrence of microplastics in sediments of artificially and non-artificially recharged lagoons from the network of endorheic wetlands called ?La Mancha Húmeda?, declared Biosphere Reserve by UNESCO. The particles sampled in this study covered the 25 ?m?5 mm range. Films were the dominant microplastic typol-ogy in non-artificially recharged lagoons, while fibres and fragments were more abundant in those receiving wastewater. The concentration of microplastics in sediments reached up to 24.4 ± 5.2 microplastics/g, while plastic litter counts yielded b1 particle/g in non-wastewater receiving lagoons. Eleven types of plastic were iden- tified using Micro-Fourier Transform Infrared Spectroscopy (micro-FTIR), the most abundant being the polyole-fins polyethylene and polypropylene, and polyester and acrylic fibres. The statistical analysis of FTIR spectra confirmed the similarity between samples taken from recharged lagoons and wastewater treatment plant effluents. Overall, our results showed that endorheic lagoons are very sensitive to the accumulation of persistent pol- lutants, which include microplastics. The recharge of lagoons with wastewater effluents to maintain water levels, even if correctly treated according to current standards, is not a sustainable practice. Due to the closed character of endorheic basins, the continuous input of wastewater led to the accumulation of microplastics in sediments of wastewater receiving lagoons up to 40 times over non-recharged lagoons

Understanding nanoplastic toxicity and their interaction with engineered cationic nanopolymers in microalgae by physiological and proteomic approaches

The amount of plastics produced per year is in constant growth alongside their use in different sectors like the textile industry, agriculture or, more recently, in nanotechnology. Under certain environmental conditions, plastics break down into smaller pieces. Those plastics in the nanosize range are the most difficult to identify, quantify and remove and therefore probably prevail in aquatic ecosystems. Likewise, nanomaterial production has been increasing exponentially and therefore their potential release to the environment poses a threat. There is a lack of knowledge regarding the combined effects of co-occurring nanopolymers on biota. In this work, we have studied the individual toxicity of polystyrene nanoplastics (PS-NPs) as well as their combined effect with generation 7 PAMAM dendrimers (G7) on the filamentous cyanobacterium Anabaena sp. PCC7120, a relevant aquatic primary producer. Exposure to PS-NPs induced the overproduction of reactive oxygen species, lipid peroxidation, membrane disruptions, intracellular acidification and a decrease in photosynthetic activity. Internalization of the nanoplastics was also observed. Combined exposure to PS-NPs and G7 lowered PS-NP toxicity and precluded their internalization. This antagonistic interaction was due to the formation of heteroaggregates. Molecular biomarkers (differentially expressed proteins, DEPs) of the toxic effect of nanoplastics, G7 and their binary mixture were identified for the first time. These molecular biomarkers may be envisaged as a molecular signature of the toxic effect of the nanopolymers and could be predictors of cellular damage caused by exposure to nanopolymer

Tracking nanoplastics in freshwater microcosms and their impacts to aquatic organisms

In this work, we used palladium-doped polystyrene NPLs (PS-NPLs with a primary size of 286 ± 4 nm) with an irregular surface morphology which allowed for particle tracking and evaluation of their toxicity on two primary producers (cyanobacterium, Anabaena sp. PCC7120 and green algae, Chlamydomonas reinhardtii) and one primary consumer (crustacean, Daphnia magna). the concentration range for Anabaena and C. reinhardtii was from 0.01 to 1000 mg/L and for D. magna, the range was from 7.5 to 120 mg/L.EC50 s ranged from 49 mg NPLs/L for D. magna (48hEC50 s) to 248 mg NPLs/L (72hEC50 s for C. reinhardtii). PS-NPLs induced dose-dependent reactive oxygen species overproduction, membrane damage and metabolic alterations. To shed light on the environmental fate of PS-NPLs, the short-term distribution of PS-NPLs under static (using lake water and sediments) and stirring (using river water and sediments) conditions was studied at laboratory scale. The results showed that most NPLs remained in the water column over the course of 48 h. The maximum percentage of settled particles (∼ 30 %) was found under stirring conditions in comparison with the ∼ 10 % observed under static ones. Natural organic matter increased the stability of the NPLs under colloidal state while organisms favored their settlement. This study expands the current knowledge of the biological effects and fate of NPLs in freshwater environment

Occurrence and identification of microplastics along a beach in the Biosphere Reserve of Lanzarote

This work studied the accumulation of plastic debris in a remote beach located in La Graciosa island (Chinijo archipelago, Canary Islands). Microplastics were sampled in the 1–5 mm mesh opening range. An average plastic density of 36.3 g/m2 was obtained with a large variability along the 90 m of the beach (from 8.5 g/m2 to 103.4 g/m2). Microplastic particles preferentially accumulated in the part of the beach protected by rocks. A total number of 9149 plastic particles were collected, recorded and measured, 87% of which corresponded to fragments. Clear colours and microscopic evidence of weathering corresponded to aged plastics wind-driven by the surface Canary Current. The chemical composition of plastics particles corresponded to PE (63%), PP (32%) and PS (3%). Higher PE/PP ratios were recorded in the more protected parts of the beach, suggesting preferential accumulation of more aged fragment