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Povzetek: Microplastic pollution is an increasing environmental issue in the marine environment due to its ubiquitous presence and its role as a vector for organic pollutants such as tributyltin (TBT). Adsorption of TBT onto microplastics (MP) can increase its availability to filter-feeding organisms by prolonging its retention time in the water column. We investigated whether polyethylene (PE) MP spheres (10–63 μm) could act as vectors for TBT transfer in the mussel Mytilus galloprovincialis by exposing it to PE MP (50 mg L− 1 ) and TBT (0.001 mg L− 1 ) separately and in co-exposure for 21 days. Efficient adsorption on PE MP was confirmed, and higher concentration of TBT was observed in the PE MP + TBT group compared to TBT only exposed group, indicating a vector effect. This led to higher toxicity in mussels, as the combined stress conditions in the PE MP + TBT group resulted in a significant decrease in the catalase activity after 14 days of the exposure. Higher ETS activity was observed in both exposed groups after seven days of exposure, followed by lower ETS activity at 14 and 21 days, indicating depletion of energy reserves. Pronounced responses in catalase and electron transport system (ETS) activity were observed in the hepatopancreas compared to the gill tissue. DNA damage was present in all exposed groups and increased over time.
Ključne besede: mytilus galloprovincialis, tributyltin, PE microplastics, mitochondrial respiration, genotoxicity, oxidative stress
Objavljeno v DiRROS: 18.05.2026; Ogledov: 102; Prenosov: 77
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Povzetek: Aerobic respiration is the main energy source for most eukaryotes, and efficient mitochondrial energy transfer greatly influences organismal fitness. To survive environmental changes, cells have evolved to adjust their biochemistry. Thus, measuring energy metabolism at the subcellular level can enhance our understanding of individual performance, population dynamics, and species distribution ranges. We investigated three important metabolic traits at the subcellular level in five lacertid lizard species sampled from different elevations, from sea level up to 2000 m. We examined hemoglobin concentration, two markers of oxidative stress (catalase activity and carbonyl concentration) and maximum rate of metabolic respiration at the subcellular level (potential metabolic activity at the electron transport system). The traits were analysed in laboratory acclimated adult male lizards to investigate the adaptive metabolic responses to the variable environmental conditions at the local sampling sites. Potential metabolic activity at the cellular level was measured at four temperatures – 28 °C, 30 °C, 32 °C and 34 °C – covering the range of preferred body temperatures of the species studied. Hemoglobin content, carbonyl concentration and potential metabolic activity did not differ significantly among species. Interspecific differences were found in the catalase activity, Potential metabolic activity increased with temperature in parallel in all five species. The highest response of the metabolic rate with temperature (Q10) and Arrhenius activation energy (Ea) was recorded in the high-mountain species Iberolacerta monticola.
Ključne besede: physiology, lacertids, aerobic respiration, interspecific variability, hemoglobin, zoology
Objavljeno v DiRROS: 03.09.2024; Ogledov: 1106; Prenosov: 1470
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Povzetek: Purpose Hyporheic biofilms are the central site for biogeochemical cycling in streams and rivers. In view of global warming and increasing human pressures, this study aimed to compare the response of hyporheic biofilm biomass and activities from an unpolluted reference stream reach surrounded by forest with those from a stream reach exposed to agricultural and urban land use using a mesocosm experiment in which the water temperature and dissolved organic carbon (DOC) contents were manipulated. Methods Hyporheic sediments collected in the field from the two study reaches (i.e. reference and impacted) were incubated in the laboratory at two different temperatures (10 °C, 14 °C) and wetted with three types of synthetic water (control [C] – 0 mg L−1; low DOC – 5 mg L−1; high DOC – 30 mg L−1) for four weeks. The responses of the hyporheic biofilms were measured weekly using structural (total protein content [TPC] as a proxy for biofilm biomass) and functional measures (electron transport system activity [ETSA] and community-level physiological profiling [CLPP]). Results The response of hyporheic biofilms to temperature changes and DOC enrichment was site-specific for all studied measures (TPC, ETSA and CLPP, including measured average well colour development [AWCD]). The addition of DOC to biofilms from the pristine stream reach significantly heightened the responses at 10 °C, a temperature within the normal environmental temperature ranges of the reference location, but not at 14 °C, which was here, a temperature outside normal environmental range. On the other hand, biofilms from the impacted stream reach exhibited increased responses following DOC enrichment under both temperature regimes, with a particularly pronounced response at 14 ºC, in this case, both experimental temperatures were within the normal environmental temperature ranges of the study locations. Conclusion Hyporheic biofilms were shown to be, like benthic biofilms, sensitive to temperature changes and organic enrichment, but their response to temperature changes and enrichment caused by climate change and/or other anthropogenic pressures (i.e. point and non-point pollution, removal of the riparian zone, hydromorphological modifications, etc.) was not simply linear but site-specific. The intensity of the response, characterized by increased activity and biomass production, appears to be constrained within the temperature ranges prevalent in the environment from which the biofilms originate. These findings emphasize the importance of site-specific considerations in predicting the impacts of climate change and anthropogenic pressures on these critical components of river and stream ecosystems.
Ključne besede: sediments, respiration, enzymes, functional indicators, interactions
Objavljeno v DiRROS: 05.08.2024; Ogledov: 1243; Prenosov: 822
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Povzetek: Clearings of the Forest (Claros del Bosque, 1977), one of the most poetic and chal-lenging works of María Zambrano’s thought, cannot be approached from a breath-less paradigm. For the immersion in these clearings take us into the breathing of being that we contemplate alongside the more obvious physiological breathing, the breathing of life. In this work, Zambrano proposes a poetic and mystical phe-nomenology of the breathing of being through the breathing of its word. Thus, to recover contact with this inner breathing could be to recover the lost chant of the word. This essay does not pretend to be a detailed analysis of Zambrano’s thought as a whole, nor of the vibrant mystery that her clearings reveal. The purpose is to uncover the fundamental role that breathing plays in this poetic-philosophical journey, along with other symbols such as light or love, with the question of what place this type of philosophical exercise occupies today in the classrooms of con-temporary universities.
Ključne besede: poetic reason, María Zambrano, being, love, Unamuno, Ortega, respiration
Objavljeno v DiRROS: 14.05.2024; Ogledov: 1122; Prenosov: 702
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Povzetek: Background. Mortality rates for patients with ARDS remain high. We assessed temporal changes in the epidemiology and management of ARDS patients requiring invasive mechanical ventilation in European ICUs. We also investigated the association between ventilatory settings and outcome in these patients. Methods. This was a post hoc analysis of two cohorts of adult ICU patients admitted between May 1–15, 2002 (SOAP study, n = 3147), and May 8–18, 2012 (ICON audit, n = 4601 admitted to ICUs in the same 24 countries as the SOAP study). ARDS was defined retrospectively using the Berlin definitions. Values of tidal volume, PEEP, plateau pressure, and FiO2 corresponding to the most abnormal value of arterial PO2 were recorded prospectively every 24 h. In both studies, patients were followed for outcome until death, hospital discharge or for 60 days. Results. The frequency of ARDS requiring mechanical ventilation during the ICU stay was similar in SOAP and ICON (327[10.4%] vs. 494[10.7%], p = 0.793). The diagnosis of ARDS was established at a median of 3 (IQ: 1–7) days after admission in SOAP and 2 (1–6) days in ICON. Within 24 h of diagnosis, ARDS was mild in 244 (29.7%), moderate in 388 (47.3%), and severe in 189 (23.0%) patients. In patients with ARDS, tidal volumes were lower in the later (ICON) than in the earlier (SOAP) cohort. Plateau and driving pressures were also lower in ICON than in SOAP. ICU (134[41.1%] vs 179[36.9%]) and hospital (151[46.2%] vs 212[44.4%]) mortality rates in patients with ARDS were similar in SOAP and ICON. High plateau pressure (> 29 cmH2O) and driving pressure (> 14 cmH2O) on the first day of mechanical ventilation but not tidal volume (> 8 ml/kg predicted body weight [PBW]) were independently associated with a higher risk of in-hospital death. Conclusion. The frequency of and outcome from ARDS remained relatively stable between 2002 and 2012. Plateau pressure > 29 cmH2O and driving pressure > 14 cmH2O on the first day of mechanical ventilation but not tidal volume > 8 ml/kg PBW were independently associated with a higher risk of death. These data highlight the continued burden of ARDS and provide hypothesis-generating data for the design of future studies.
Ključne besede: respiratory insufficiency, artificial respiration, tidal volume, airway pressures, driving pressure
Objavljeno v DiRROS: 16.06.2021; Ogledov: 3601; Prenosov: 1631
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