خيارات البحث
النتائج 5761 - 5770 من 6,560
Distribution of dinoflagellate cyst assemblages in recent sediments from a southern Mediterranean lagoon (Mellah, Algeria) with emphasis on toxic species النص الكامل
2020
Draredja, Mohamed Anis | Frihi, Hocine | Boualleg, Chahinaise | Abadie, Eric | Laabir, Mohamed
This is the first study on the dinoflagellate cysts in Algerian waters and in Mellah Lagoon (South Western Mediterranean), located within a protected reserve. In total, 42 species of dinocysts belonging to 7 orders, 12 families and 23 genera, were identified in the 26 superficial sediment samples from Mellah Lagoon. The distribution of dinocysts in the sediment of this lagoon is heterogeneous. Indeed, their abundance oscillates between 1 and 315 cysts g⁻¹ dry sediment (DS). Cyst morphotype assemblages were dominated by a few numbers of species: Alexandrium minutum (15.87%), Gonyaulax verior (9.81%), Protoperidinium spp. (7.74%), Alexandrium affine (7.05%), Scrippsiella trochoidea (6.67%), and Alexandrium pseudogonyaulax (6.19%). There is a positive correlation between the density of cysts and the depth (r = 0.61; p < 0.05), organic matter (r = 0.70; p < 0.05), water content (r = 0.71; p < 0.05), and the fine fraction of sediment (r = 0.74; p < 0.05). Surprisingly, although the Mellah Lagoon is almost semi-closed, it holds an important specific richness in dinocysts (42 species) higher than others observed in Mediterranean lagoons. However, cyst abundances are low compared to other lagoons in the Mediterranean Sea. Finally, the presence of dinocysts of Alexandrium catenella/tamarense, A. minutum, and Gymnodinium catenatum associated to paralytic shellfish toxins, A. pseudogonyaulax which produces goniodomin A, also Protoceratium reticulatum and Gonyaulax spinifera complex which produce yessotoxins, needs to implement a monitoring program to prevent a potential human intoxication due to the consumption of contaminated sea products by these potent neurotoxins.
اظهر المزيد [+] اقل [-]Oxythermal window drastically constraints the survival and development of European sturgeon early life phases النص الكامل
2020
Delage, Nicolas | Couturier, Blandine | Jatteau, Philippe | Larcher, Thibaut | Ledevin, Mireille | Goubin, Hélicia | Cachot, Jérôme | Rochard, Eric
European sturgeon Acipenser sturio is an anadromous fish species being classified “critically endangered” with only one remaining population in the Gironde-Garonne-Dordogne basin (France). In the global warming context, this paper aims to determine the sensitivity of A. sturio early life phases to temperature and oxygen saturation. Embryos were experimentally exposed to a combination of temperature (12 to 30 °C) and oxygen (30 to 90% O₂ saturation) conditions. Lethal and sublethal effects were evaluated using embryonic mortality, hatching success, malformation rate, yolk sac resorption, tissue development and swimming speed. Embryonic survival peaked at 20 °C and no survival was recorded at 30 °C regardless of the associated oxygen saturation. No hatching occurred at 50% O₂ sat or below regardless of temperature. Malformation frequency appeared to be minimum at 20 °C and 90% O₂ sat. Swimming speed peaked at 16 °C. The temperature optimum of early life phases of A. sturio was determined to be close to 20 °C. Its upper tolerance limit is between 26 and 30 °C and its lower tolerance limit is below 12 °C. Oxygen depletion induces sublethal effects at 70% O₂ sat and lethal effects at 50% O₂ sat. Within the spawning period in the Gironde-Garonne-Dordogne basin, we identified yearly favourable oxythermal windows. Consequences of climate change would depend of the phenological adaptation of the species for its spawning period.
اظهر المزيد [+] اقل [-]Biomarker considerations in monitoring petrogenic pollution using the mussel Mytilus galloprovincialis النص الكامل
2020
Solé, Montserrat | Freitas, Rosa | Viñas, Lucia | Rivera-Ingraham, Georgina A.
Mussels are worldwide bioindicators in pollution monitoring since they fulfil the requirements for being good sentinels. However, some methodological concerns arise in the use of particular biomarkers, particularly those displaying low enzymatic rates and/or limited responsiveness to chemicals and biological-related variability. In the present study, the suitability of oxidative stress and detoxification parameters when using mussels as sentinels of polycyclic aromatic hydrocarbon (PAH) pollution is addressed. Present results show that the S9 subcellular fraction of the digestive gland in mussels is an adequate and convenient matrix where to measure most pollution-related biomarkers. Furthermore, this work constitutes the first evidence of the potential suitability of using particular carboxylesterase (CE) activities in determining PAHs exposure in mussels. This fact could imply the replacement of more controversial cytochrome P450 components (phase I oxidation), which are only measurable in microsomal fractions, by CEs (measured in S9 fractions) as good alternatives for phase I reactions in PAH-exposed mussels. Some methodological considerations, such as the need of including commercial purified proteins in biomarker determinations for quality assurance, are evaluated.
اظهر المزيد [+] اقل [-]Upcycling spent brewery grains through the production of carbon adsorbents—application to the removal of carbamazepine from water النص الكامل
2020
Sousa, Andreia F. C. | Gil, María Victoria | Calisto, Vânia
Spent brewery grains, a by-product of the brewing process, were used as precursor of biochars and activated carbons to be applied to the removal of pharmaceuticals from water. Biochars were obtained by pyrolysis of the raw materials, while activated carbons were produced by adding a previous chemical activation step. The influence of using different precursors (from distinct fermentation processes), activating agents (potassium hydroxide, sodium hydroxide, and phosphoric acid), pyrolysis temperatures, and residence times was assessed. The adsorbents were physicochemically characterized and applied to the removal of the antiepileptic carbamazepine from water. Potassium hydroxide activation produced the materials with the most promising properties and adsorptive removals, with specific surface areas up to 1120 m² g⁻¹ and maximum adsorption capacities up to 190 ± 27 mg g⁻¹ in ultrapure water. The adsorption capacity suffered a reduction of < 70% in wastewater, allowing to evaluate the impact of realistic matrices on the efficiency of the materials.
اظهر المزيد [+] اقل [-]Biomarker and hematological fieldwork with amphibians: is it necessary to sample all night? النص الكامل
2020
Brodeur, Julie Céline | Bahl, María Florencia | Natale, Guillermo Sebastián | Poliserpi, María Belén
In the context of the global amphibian crisis, biomonitoring constitutes a valuable assessment tool to provide critical up to date information on the status and health of amphibians worldwide. The aim of the current study was to evaluate the possible confounding effects of sex, size, and time since capture on enzymatic biomarkers and hematologic parameters of the South American frog Leptodactylus latrans. Frogs were collected by hand between 9 pm and 12 am on two consecutive nights. On the first night, captured frogs were transported for 2 h by car to laboratory installations, maintained overnight in plastic containers, and blood and tissue sampled on the next morning. In contrast, frogs collected on the second night were blood and tissue sampled in the field, immediately after the capture period. Hematological parameters were analyzed, and enzymatic activities of catalase, cholinesterase (ChE), and glutathione S-transferase (GST) were determined in the plasma, liver, kidney, and muscle. A sex difference was observed only for total white blood cell counts (WBC), females exhibiting significantly greater values than males. The packed cell volume (PCV), mean corpuscular hemoglobin concentration (MCHC), WBC, and muscle ChE activity were significantly correlated with snout-vent length (SVL). The correlation was inversed in the case of MCHC, WBC, and muscle ChE, while the correlation was positive between PCV and SVL. Most examined parameters presented similar values when frogs were sampled at night following capture or the next morning. Total red blood cells (RBCs) count, and plasma enzymatic activities of ChE and GST were the only parameters that presented significantly increased values in morning samplings compared with night samplings. Overall, the current study indicates that it is best to sample the frogs as soon as possible after capture if hematologic or plasmatic biomarkers are examined. Nevertheless, it is possible to sample on the next morning if tissular biomarkers are employed.
اظهر المزيد [+] اقل [-]Linear toxicokinetic of chlordecone in ewe’s serum النص الكامل
2020
Saint-Hilaire, Maïlie | Rychen, Guido | Thomé, Jean-Pierre | Joaquim-Justo, Célia | Le Roux, Yves | Feidt, Cyril | Fournier, Agnès
Chlordecone (CLD) is an organochlorine pesticide used in banana fields of the French West Indies between 1972 and 1993. This use resulted in a long-term pollution of soils and the possible contamination of farm animals. Indeed, after involuntary ingestion of soil, CLD is absorbed and consequently leads to contaminated animals. The aim of this study was the determination of CLD half-life and the establishment of the linearity of CLD disappearance kinetics in non-lactating adult’s ewes. Chlordecone diluted in cremophor was intravenously administrated to ewes at different doses: 0.04, 0.2, or 1 mg kg⁻¹ body weight (n = 5 for each dose). Blood samples were collected from time t = 0 to time t = 84 days. Serum samples were extracted with a solid-phase extraction and analyzed by electron capture detection gas chromatography. A two-compartmental model was applied to the serum CLD kinetics. An additional statistical analysis was applied to the observed elimination parameters in serum according to the administrated dose, and no significant differences were detected. The linear elimination of CLD between 0.04 and 1 mg kg⁻¹ body weight allowed the possibility of ewe’s extrapolation half-life in this dose range. The estimated mean CLD half-life in ewes was 24 days. Overall, the results of this study will be useful to establish decontamination strategies in small ruminants reared in contaminated CLD areas. Graphical abstract Experimental design of the CLD toxicokinetic study in ewes
اظهر المزيد [+] اقل [-]Influence of climate on energy consumption and CO2 emissions: the case of Spain النص الكامل
2020
Zarco-Soto, Irene M. | Zarco-Periñán, Pedro J. | Sánchez-Durán, Rafael
This paper presents a methodology that allows for calculating the thermal and electric energy consumption together with CO₂ emissions of cities by inhabitant and household based on climate, only making use of publicly available data. With this aim, climate was analysed and cities were classified based on it. The analysis of those cities’ energy consumption and CO₂ emissions allowed for drawing conclusions. Once aware of the climate zones in which energy consumption and emissions are higher, these mentioned conclusions could help to take further actions. An index has been defined to facilitate this analysis. This paper shows the case of Spain for illustrative purposes. This type of study has been carried out in some detail in many countries, but not in Spain yet. This paper tries as well to fill the existing gaps in studies that relate climate to thermal and electric energy consumption. For this purpose, it analyses the 145 cities in Spain that have more than 50,000 inhabitants. Knowing all this is essential in all regions and countries. It will allow for taking proper actions for promoting the energy saving and the use of alternative energy sources that reduce CO₂ emissions. According to the study carried out in this paper, the extremer the climate of a city is, the higher the thermal energy consumption is. This consumption decreases in softer climates. However, electric energy consumption is similar in all cities independent of the climate they have. With regard to CO₂ emissions, it was calculated that the higher the energy consumption of a city is, the higher these emissions are.
اظهر المزيد [+] اقل [-]Evaluating the presence of microplastics in striped dolphins (Stenella coeruleoalba) stranded in the Western Mediterranean sea. النص الكامل
2020
Novillo Sanjuan, Olga | Raga Esteve, Juan Antonio | Tomás Aguirre, Jesús
Evaluating the presence of microplastics in striped dolphins (Stenella coeruleoalba) stranded in the Western Mediterranean sea. النص الكامل
2020
Novillo Sanjuan, Olga | Raga Esteve, Juan Antonio | Tomás Aguirre, Jesús
Litter is a well-known problem for marine species; however, we still know little about the extent to which they're affected by microplastics. In this study, we analyse tl1e presence of this type of debris in Western Mecliterranean striped dolphins' intestinal contents over three decades. Results indicated that frequency was high, as 90.5% of dolphins contained microplastics. Of these microplastics, 73.6% were fibres, 23.87% were fragments and 2.53% were prirnary pellets. In spite of the high frequency of occurrence, microplastic amount per dolphin was relatively low and highly variable (mean ± SD = 14.9 ± 22.3; 95% CI: 9.58--23.4). Through FT-IR spectrometry, we found that polyacrylamide, typically found in synthetic clothes, was the most common plastic polymer. Here, we establish a starting point for further research on how microplastics affect this species' health and discuss the use of striped dolphins as indicators of microplastics at sea.
اظهر المزيد [+] اقل [-]Evaluating the presence of microplastics in striped dolphins (Stenella coeruleoalba) stranded in the Western Mediterranean Sea النص الكامل
2020
Novillo, O. | Raga, J.A. | Tomas, J.
Litter is a well-known problem for marine species; however, we still know little about the extent to which they're affected by microplastics. In this study, we analyse the presence of this type of debris in Western Mediterranean striped dolphins' intestinal contents over three decades. Results indicated that frequency was high, as 90.5% of dolphins contained microplastics. Of these microplastics, 73.6% were fibres, 23.87% were fragments and 2.53% were primary pellets. In spite of the high frequency of occurrence, microplastic amount per dolphin was relatively low and highly variable (mean ± SD = 14.9 ± 22.3; 95% CI: 9.58–23.4). Through FT-IR spectrometry, we found that polyacrylamide, typically found in synthetic clothes, was the most common plastic polymer. Here, we establish a starting point for further research on how microplastics affect this species' health and discuss the use of striped dolphins as indicators of microplastics at sea.
اظهر المزيد [+] اقل [-]Inorganic and organic characterization of Santa Lucía salt mine peloid for quality evaluations النص الكامل
2020
Martínez-Villegas, Nadia | Suárez Muñoz, Margaret | González-Hernández, Patricia | Melián Rodríguez, Clara | Barrios Cossio, Josiel | Hernández Díaz, Rebeca | Fagundo Castillo, Juan R. | Gelen Rudnikas, Alina | Díaz López, Cristina | Pérez-Gramatges, Aurora | Díaz Rizo, Oscar
Santa Lucía peloid is a sediment used in pelotherapy in Cuban primary health care services. Therefore, in addition to physicochemical regulated parameters, other analyses are required to complement their physicochemical characterization and understand potential element mobility, radiological risk, and toxicity as well as likely bioactive compounds present in Santa Lucía peloid. For these purposes, inorganic and organic elements and compounds were considered to evaluate Santa Lucía peloid’s quality. This was accomplished through an integral approach that included (1) determination of physicochemical parameters (pH, electrical conductivity, oxidation–reduction potential, temperature, dissolved oxygen, elemental C, H, and N analyses, organic matter, and hexane removable substances content); (2) determination of total concentration of elements with biological and toxicological importance (i.e., Na, K, Ca, Mg, Fe, Mn, Cr, Cu, Ni, Pb, and Zn), as well as their distribution in operationally defined solid phases, mineralogy, particle size distribution, and total content of radionuclides and radiological dose calculations; and (3) its organic characterization. Results from this study showed that Santa Lucía peloid was non-contaminated and showed low metal mobility and acceptable radiological dose levels, being safe for therapeutic uses. Additionally, these results contribute to the understanding of the organic composition of peloides, provide strong evidences to scientifically explain the therapeutic action of peloids in the treatment of inflammatory diseases, and set a new frame to improve peloid guidelines in Cuba and other countries.
اظهر المزيد [+] اقل [-]Low-dose Roundup induces developmental toxicity in bovine preimplantation embryos in vitro النص الكامل
2020
Cai, Wenyang | Yang, Xiao | Li, Xiangchen | Li, Hongtu | Wang, Shuo | Wu, Zhengchao | Yu, Mingxi | Ma, Shiliang | Tang, Shuang
Roundup is a widely used glyphosate-based herbicide worldwide. Roundup residues can be detected in the organs and urine of animals. However, its toxicity on mammalian preimplantation embryos has not been well investigated. Here, we show Roundup impairs the development and quality of bovine preimplantation embryos in a dose-dependent manner. Exposure to the agricultural recommended doses of Roundup caused in vitro developmental arrest and quick death of bovine embryos. Furthermore, even a very low concentration (0.9 ppm) of Roundup was harmful to bovine preimplantation development. In addition, Roundup increases intracellular calcium levels and induces oxidative stress and apoptosis in bovine embryos. Even if the embryos developed to morphologically normal blastocysts when cultured with low concentrations of Roundup, abnormal intracellular calcium and oxidative stress could be detected inside the embryos and led to an increased incidence of apoptosis in the blastocysts. These data suggest Roundup residues from the agricultural application are potentially dangerous to mammalian preimplantation embryos.
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