Remote in vivo stress assessment of aquatic animals with microencapsulated biomarkers for environmental monitoring

Remote in vivo scanning of physiological parameters is a major trend in the development of new tools for the fields of medicine and animal physiology. For this purpose, a variety of implantable optical micro- and nanosensors have been designed for potential medical applications. At the same time, the important area of environmental sciences has been neglected in the development of techniques for remote physiological measurements. In the field of environmental monitoring and related research, there is a constant demand for new effective and quick techniques for the stress assessment of aquatic animals, and the development of proper methods for remote physiological measurements in vivo may significantly increase the precision and throughput of analyses in this field. In the present study, we apply pH-sensitive microencapsulated biomarkers to remotely monitor the pH of haemolymph in vivo in endemic amphipods from Lake Baikal, and we compare the suitability of this technique for stress assessment with that of common biochemical methods. For the first time, we demonstrate the possibility of remotely detecting a change in a physiological parameter in an aquatic organism under ecologically relevant stressful conditions and show the applicability of techniques using microencapsulated biomarkers for remote physiological measurements in environmental monitoring

Molecular Mechanisms and New Treatment Paradigm for Atrial Fibrillation.

Atrial fibrillation represents the most common arrhythmia leading to increased morbidity and mortality, yet, current treatment strategies have proven inadequate. Conventional treatment with antiarrhythmic drugs carries a high risk for proarrhythmias. The soluble epoxide hydrolase enzyme catalyzes the hydrolysis of anti-inflammatory epoxy fatty acids, including epoxyeicosatrienoic acids from arachidonic acid to the corresponding proinflammatory diols. Therefore, the goal of the study is to directly test the hypotheses that inhibition of the soluble epoxide hydrolase enzyme can result in an increase in the levels of epoxyeicosatrienoic acids, leading to the attenuation of atrial structural and electric remodeling and the prevention of atrial fibrillation. For the first time, we report findings that inhibition of soluble epoxide hydrolase reduces inflammation, oxidative stress, atrial structural, and electric remodeling. Treatment with soluble epoxide hydrolase inhibitor significantly reduces the activation of key inflammatory signaling molecules, including the transcription factor nuclear factor κ-light-chain-enhancer, mitogen-activated protein kinase, and transforming growth factor-β. This study provides insights into the underlying molecular mechanisms leading to atrial fibrillation by inflammation and represents a paradigm shift from conventional antiarrhythmic drugs, which block downstream events to a novel upstream therapeutic target by counteracting the inflammatory processes in atrial fibrillation

Molecular Mechanisms and New Treatment Paradigm for Atrial Fibrillation

BACKGROUND: Atrial fibrillation (AF) represents the most common arrhythmia leading to increased morbidity and mortality, yet, current treatment strategies have proven inadequate. Conventional treatment with antiarrhythmic drugs carries a high risk for proarrhythmias. The soluble epoxide hydrolase enzyme (sEH) catalyzes the hydrolysis of anti-inflammatory epoxy fatty acids including epoxyeicosatrienoic acids (EETs) from arachidonic acid to the corresponding pro-inflammatory diols. Therefore, the goal of the study is to directly test the hypotheses that inhibition of the sEH enzyme can result in an increase in the levels of EETs leading to the attenuation of atrial structural and electrical remodeling and the prevention of AF. METHODS AND RESULTS: For the first time, we report findings that inhibition of sEH reduces inflammation, oxidative stress, atrial structural and electrical remodeling. Treatment with sEH inhibitor significantly reduces the activation of key inflammatory signaling molecules, including the transcription factor nuclear factor κ-light-chain-enhancer (NF-κB), mitogen-activated protein kinase (MAPK) and transforming growth factor-β (TGF-β). CONCLUSIONS: This study provides insights into the underlying molecular mechanisms leading to AF by inflammation and represents a paradigm shift from conventional antiarrhythmic drugs which block downstream events to a novel upstream therapeutic target by counteracting the inflammatory processes in AF

Humic acid can mitigate the toxicity of small copper oxide nanoparticles to microbial decomposers and leaf decomposition in streams

As the use of copper oxide nanoparticles (nanoCuO) in consumer products grows, aquatic ecosystems are likely to receive increasing amounts of these nanomaterials. Dissolved organic matter (DOM) may interact with nanoparticles and reduce their reactive surface area, which, in turn, can influence the impact of nanoCuO on organisms and ecological processes. We conducted a microcosm experiment to investigate the impacts of three size classes of nanoCuO (12, 50 and 80nm mean diameter of the primary particles; five levels up to 400mgL(-1)) and humic acid (three levels up to 100mgL(-1)), as a major component of DOM, on microbial decomposers and leaf decomposition as an important ecosystem process in forest streams. Exposure to nanoCuO for 20days reduced decomposition rate and fungal and bacterial biomass, fungal sporulation and spore diversity associated with the decomposing leaves. The effects were stronger as nanoparticle size decreased and the specific surface area increased. More dissolved ionic copper was released from the small nanoparticles, suggesting that Cu2+ could have played a role in the observed size-dependent toxicity of nanoCuO. Bacteria appeared to be more sensitive to nanoCuO than fungi since nanoparticles reduced the biomass of bacteria at lower concentrations than that of fungi (EC20 was 22 times lower for small and medium-sized nanoparticles, and five times lower for large particles). However, fungal sporulation was the variable most sensitive to nanoCuO exposure (EC20=0.2mgL(-1) for the small nanoparticles). Microbial activity on the decomposing leaves was also inhibited by exposure to humic acid alone. However, humic acid also mitigated the adverse effects of the small and medium-sized nanoCuO on both the microbial decomposers and leaf decomposition. Overall, our microcosm experiment indicates that nanoCuO toxicity to microbial decomposers and leaf decomposition depends on particle size and the presence of DOM. This highlights the importance of considering environmental context and the specific prFEDER-POFC-COMPETE and the Portuguese Foundation for Science and Technology supported this work (PEst-OE/BIA/UI4050/2014, PTDC/AAC-AMB/121650/2010), A. Pradhan (SFRH/BD/45614/2008) and P. Geraldes (SFRH/BD/75516/2010).info:eu-repo/semantics/publishedVersio