Base de dados : MEDLINE
Pesquisa : B01.650.940.800.575.912.250.618.050 [Categoria DeCS]
Referências encontradas : 365 [refinar]
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  1 / 365 MEDLINE  
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PMID:28813506
Autor:Jiménez-Ramos R; Egea LG; Ortega MJ; Hernández I; Vergara JJ; Brun FG
Endereço:Departament of Biology (Division of Ecology), Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, Spain.
Título:Global and local disturbances interact to modify seagrass palatability.
Fonte:PLoS One; 12(8):e0183256, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Global change, such as warming and ocean acidification, and local anthropogenic disturbances, such as eutrophication, can have profound impacts on marine organisms. However, we are far from being able to predict the outcome of multiple interacting disturbances on seagrass communities. Herbivores are key in determining plant community structure and the transfer of energy up the food web. Global and local disturbances may alter the ecological role of herbivory by modifying leaf palatability (i.e. leaf traits) and consequently, the feeding patterns of herbivores. This study evaluates the main and interactive effects of factors related to global change (i.e. elevated temperature, lower pH levels and associated ocean acidification) and local disturbance (i.e. eutrophication through ammonium enrichment) on a broad spectrum of leaf traits using the temperate seagrass Cymodocea nodosa, including structural, nutritional, biomechanical and chemical traits. The effect of these traits on the consumption rates of the generalist herbivore Paracentrotus lividus (purple sea urchin) is evaluated. The three disturbances of warming, low pH level and eutrophication, alone and in combination, increased the consumption rate of seagrass by modifying all leaf traits. Leaf nutritional quality, measured as nitrogen content, was positively correlated to consumption rate. In contrast, a negative correlation was found between feeding decisions by sea urchins and structural, biomechanical and chemical leaf traits. In addition, a notable accomplishment of this work is the identification of phenolic compounds not previously reported for C. nodosa. Our results suggest that global and local disturbances may trigger a major shift in the herbivory of seagrass communities, with important implications for the resilience of seagrass ecosystems.
Tipo de publicação: JOURNAL ARTICLE


  2 / 365 MEDLINE  
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PMID:28792960
Autor:Guilini K; Weber M; de Beer D; Schneider M; Molari M; Lott C; Bodnar W; Mascart T; De Troch M; Vanreusel A
Endereço:Marine Biology Research Group, Department of Biology, Ghent University, Ghent, Belgium.
Título:Response of Posidonia oceanica seagrass and its epibiont communities to ocean acidification.
Fonte:PLoS One; 12(8):e0181531, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:The unprecedented rate of CO2 increase in our atmosphere and subsequent ocean acidification (OA) threatens coastal ecosystems. To forecast the functioning of coastal seagrass ecosystems in acidified oceans, more knowledge on the long-term adaptive capacities of seagrass species and their epibionts is needed. Therefore we studied morphological characteristics of Posidonia oceanica and the structure of its epibiont communities at a Mediterranean volcanic CO2 vent off Panarea Island (Italy) and performed a laboratory experiment to test the effect of OA on P. oceanica photosynthesis and its potential buffering capacity. At the study site east of Basiluzzo Islet, venting of CO2 gas was controlled by tides, resulting in an average pH difference of 0.1 between the vent and reference site. P. oceanica shoot and leaf density was unaffected by these levels of OA, although shorter leaves at the vent site suggest increased susceptibility to erosion, potentially by herbivores. The community of sessile epibionts differed in composition and was characterized by a higher species richness at the vent site, though net epiphytic calcium carbonate concentration was similar. These findings suggest a higher ecosystem complexity at the vent site, which may have facilitated the higher diversity of copepods in the otherwise unaffected motile epibiont community. In the laboratory experiment, P. oceanica photosynthesis increased with decreasing pHT (7.6, 6.6, 5.5), which induced an elevated pH at the leaf surfaces of up to 0.5 units compared to the ambient seawater pHT of 6.6. This suggests a temporary pH buffering in the diffusive boundary layer of leaves, which could be favorable for epibiont organisms. The results of this multispecies study contribute to understanding community-level responses and underlying processes in long-term acidified conditions. Increased replication and monitoring of physico-chemical parameters on an annual scale are, however, recommended to assure that the biological responses observed during a short period reflect long-term dynamics of these parameters.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:142M471B3J (Carbon Dioxide); H0G9379FGK (Calcium Carbonate); S88TT14065 (Oxygen)


  3 / 365 MEDLINE  
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PMID:28789591
Autor:Ben Salem Y; Abdelhamid A; Mkadmini Hammi K; Le Cerf D; Bouraoui A; Majdoub H
Endereço:a Laboratoire des Interfaces et des Matériaux Avancés (LIMA), Faculté des Sciences de Monastir , Université de Monastir , Monastir , Tunisia.
Título:Microwave-assisted extraction and pharmacological evaluation of polysaccharides from Posidonia oceanica.
Fonte:Biosci Biotechnol Biochem; 81(10):1917-1925, 2017 Oct.
ISSN:1347-6947
País de publicação:England
Idioma:eng
Resumo:Microwave-assisted extraction was employed for the isolation of polysaccharides from Posidonia oceanica (PPO). The extracting parameters were optimized adopting response surface methodology. The highest polysaccharide yield (2.55 ± 0.09%), which is in concordance with the predicted value (2.76%), was obtained under the following conditions: extraction time 60 s, liquid-solid ratio of 50:1 (mL/g) and power of 800 W. This polysaccharide, with molecular weight of 524 KDa, characterized by gas chromatography-mass spectrometry showed that PPO was mainly composed of galactose, glucose, and arabinose with molar percentages 25.38, 24.37, and 21.64%, respectively. The pharmacological evaluation of PPO using animal models at the dose of 100 mg/kg indicated a significant anti-inflammatory activity with a percentage of inhibition of edema of 54.65% and a significant antinociceptive activity with 78.91% inhibition of writhing for peripheral analgesic activity and an increase in the hot plate reaction time for central analgesic activity.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Analgesics); 0 (Anti-Inflammatory Agents, Non-Steroidal); 0 (Polysaccharides); Q40Q9N063P (Acetic Acid)


  4 / 365 MEDLINE  
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PMID:28704565
Autor:Deyanova D; Gullström M; Lyimo LD; Dahl M; Hamisi MI; Mtolera MSP; Björk M
Endereço:Seagrass Ecology & Physiology Research Group, Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden.
Título:Contribution of seagrass plants to CO2 capture in a tropical seagrass meadow under experimental disturbance.
Fonte:PLoS One; 12(7):e0181386, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Coastal vegetative habitats are known to be highly productive environments with a high ability to capture and store carbon. During disturbance this important function could be compromised as plant photosynthetic capacity, biomass, and/or growth are reduced. To evaluate effects of disturbance on CO2 capture in plants we performed a five-month manipulative experiment in a tropical seagrass (Thalassia hemprichii) meadow exposed to two intensity levels of shading and simulated grazing. We assessed CO2 capture potential (as net CO2 fixation) using areal productivity calculated from continuous measurements of diel photosynthetic rates, and estimates of plant morphology, biomass and productivity/respiration (P/R) ratios (from the literature). To better understand the plant capacity to coping with level of disturbance we also measured plant growth and resource allocation. We observed substantial reductions in seagrass areal productivity, biomass, and leaf area that together resulted in a negative daily carbon balance in the two shading treatments as well as in the high-intensity simulated grazing treatment. Additionally, based on the concentrations of soluble carbohydrates and starch in the rhizomes, we found that the main reserve sources for plant growth were reduced in all treatments except for the low-intensity simulated grazing treatment. If permanent, these combined adverse effects will reduce the plants' resilience and capacity to recover after disturbance. This might in turn have long-lasting and devastating effects on important ecosystem functions, including the carbon sequestration capacity of the seagrass system.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:142M471B3J (Carbon Dioxide)


  5 / 365 MEDLINE  
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PMID:28586672
Autor:Unsworth RKF; Cullen-Unsworth LC
Endereço:Department of Biosciences, Wallace Building, Swansea University, Swansea, SA2 8PP, UK; Sustainable Places Research Institute, Cardiff University, UK. Electronic address: r.k.f.unsworth@swansea.ac.uk.
Título:Seagrass meadows.
Fonte:Curr Biol; 27(11):R443-R445, 2017 Jun 05.
ISSN:1879-0445
País de publicação:England
Idioma:eng
Resumo:Seagrass meadows are an important and threatened ecosystem.
Tipo de publicação: JOURNAL ARTICLE


  6 / 365 MEDLINE  
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PMID:28545148
Autor:Petersen G; Cuenca A; Zervas A; Ross GT; Graham SW; Barrett CF; Davis JI; Seberg O
Endereço:Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark.
Título:Mitochondrial genome evolution in Alismatales: Size reduction and extensive loss of ribosomal protein genes.
Fonte:PLoS One; 12(5):e0177606, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:The order Alismatales is a hotspot for evolution of plant mitochondrial genomes characterized by remarkable differences in genome size, substitution rates, RNA editing, retrotranscription, gene loss and intron loss. Here we have sequenced the complete mitogenomes of Zostera marina and Stratiotes aloides, which together with previously sequenced mitogenomes from Butomus and Spirodela, provide new evolutionary evidence of genome size reduction, gene loss and transfer to the nucleus. The Zostera mitogenome includes a large portion of DNA transferred from the plastome, yet it is the smallest known mitogenome from a non-parasitic plant. Using a broad sample of the Alismatales, the evolutionary history of ribosomal protein gene loss is analyzed. In Zostera almost all ribosomal protein genes are lost from the mitogenome, but only some can be found in the nucleus.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (DNA, Plant); 0 (Ribosomal Proteins)


  7 / 365 MEDLINE  
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PMID:28476005
Autor:Tarrahi R; Khataee A; Movafeghi A; Rezanejad F; Gohari G
Endereço:Department of Plant Biology, Faculty of Natural Sciences, University of Tabriz, 51666-16471 Tabriz, Iran; Research Laboratory of Advanced Water and Wastewater Treatment Processes, Department of Applied Chemistry, Faculty of Chemistry, University of Tabriz, 51666-16471 Tabriz, Iran.
Título:Toxicological implications of selenium nanoparticles with different coatings along with Se on Lemna minor.
Fonte:Chemosphere; 181:655-665, 2017 Aug.
ISSN:1879-1298
País de publicação:England
Idioma:eng
Resumo:Nanoparticles have potential high risks for living organisms in the environment due to their specific qualities and their easy access. In the present study, selenium nanoparticles (Se NPs) with two different coatings (l-cysteine and tannic acid) were synthesized. The characteristics of particles were analyzed using XRD, FT-IR and SEM. The impact of the nanoparticles besides Se , on the aquatic higher plant Lemna minor was evaluated and compared. Entrance of l-cysteine and tannic acid capped Se NPs in the roots of Lemna minor was proved by TEM and fluorescence microscopy. Adverse effects of mentioned NPs and differences of these effects from those by sodium selenite as the ionic form were assessed by a range of biophysicochemical tests. Altogether, the results asserted that Lemna minor was notably poisoned by both capped Se NPs and Se . Thus, growth and photosynthetic pigments were decreased while lipid peroxidation along with total phenol and flavonoid contents were raised. Eventually some changes in enzymatic activities were presented. To sum up the consequences, it can be concluded that all changes occurred due to the plant defense system especially in order to remove reactive oxygen species (ROS) and possible phytotoxicity originated by l- cysteine and tannic acid capped Se NPs in addition to Se . The influence of tannic acid capped Se NPs after sodium selenite is stronger by the means of antioxidant enzymes activity in comparison with l-cysteine capped Se NPs.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Reactive Oxygen Species); 0 (Selenium Compounds); 0 (Tannins); H6241UJ22B (Selenium); HIW548RQ3W (Sodium Selenite); K848JZ4886 (Cysteine)


  8 / 365 MEDLINE  
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PMID:28441407
Autor:Boestfleisch C; Papenbrock J
Endereço:Institute of Botany, Leibniz University Hannover, Hannover, Germany.
Título:Changes in secondary metabolites in the halophytic putative crop species Crithmum maritimum L., Triglochin maritima L. and Halimione portulacoides (L.) Aellen as reaction to mild salinity.
Fonte:PLoS One; 12(4):e0176303, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:It is assumed that salinity enhances the concentration of valuable metabolites in halophytes. The objective was to find a salt concentration and a point in time at which the yield for the valuable metabolites was maximal. Therefore, three different halophyte species were grown under different salinities and harvested over a period from shortly after stress induction up to three weeks. Various reaction patterns were found in the metabolite composition of the analyzed plant material. Halimione portulacoides showed a "short term response", indicated by an increase in all metabolites analyzed after a few hours, whereas Crithmum maritimum showed a "long term response" through accumulation of proline starting after days. Triglochin maritima did not change in metabolite concentration, but like the other plant species the biomass was reduced by salinity. Generally, a higher production in secondary metabolites by higher salinity was outbalanced by a reduction in biomass production. Concentrations of analyzed antioxidants showed a similar reaction and correlated with each other.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:451W47IQ8X (Sodium Chloride)


  9 / 365 MEDLINE  
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PMID:28413104
Autor:Nogueira P; Gambi MC; Vizzini S; Califano G; Tavares AM; Santos R; Martínez-Crego B
Endereço:Centre of Marine Sciences (CCMAR), University of Algarve-Campus de Gambelas, 8005-139 Faro, Portugal.
Título:Altered epiphyte community and sea urchin diet in Posidonia oceanica meadows in the vicinity of volcanic CO vents.
Fonte:Mar Environ Res; 127:102-111, 2017 Jun.
ISSN:1879-0291
País de publicação:England
Idioma:eng
Resumo:Ocean acidification (OA) predicted for 2100 is expected to shift seagrass epiphyte communities towards the dominance of more tolerant non-calcifying taxa. However, little is known about the indirect effects of such changes on food provision to key seagrass consumers. We found that epiphyte communities of the seagrass Posidonia oceanica in two naturally acidified sites (i.e. north and south sides of a volcanic CO vent) and in a control site away from the vent at the Ischia Island (NW Mediterranean Sea) significantly differed in composition and abundance. Such differences involved a higher abundance of non-calcareous crustose brown algae and a decline of calcifying polychaetes in both acidified sites. A lower epiphytic abundance of crustose coralline algae occurred only in the south side of the vents, thus suggesting that OA may alter epiphyte assemblages in different ways due to interaction with local factors such as differential fish herbivory or hydrodynamics. The OA effects on food items (seagrass, epiphytes, and algae) indirectly propagated into food provision to the sea urchin Paracentrotus lividus, as reflected by a reduced P. oceanica exploitation (i.e. less seagrass and calcareous epiphytes in the diet) in favour of non-calcareous green algae in both vent sites. In contrast, we detected no difference close and outside the vents neither in the composition of sea urchin diet nor in the total abundance of calcareous versus non-calcareous taxa. More research, under realistic scenarios of predicted pH reduction (i.e. ≤ 0.32 units of pH by 2100), is still necessary to better understand cascading effects of this altered urchin exploitation of food resources under acidified conditions on ecosystem diversity and function.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:142M471B3J (Carbon Dioxide)


  10 / 365 MEDLINE  
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PMID:28334391
Autor:Trevathan-Tackett SM; Seymour JR; Nielsen DA; Macreadie PI; Jeffries TC; Sanderman J; Baldock J; Howes JM; Steven ADL; Ralph PJ
Endereço:Climate Change Cluster, University of Technology Sydney, NSW 2007, Australia.
Título:Sediment anoxia limits microbial-driven seagrass carbon remineralization under warming conditions.
Fonte:FEMS Microbiol Ecol; 93(6), 2017 Jun 01.
ISSN:1574-6941
País de publicação:England
Idioma:eng
Resumo:Seagrass ecosystems are significant carbon sinks, and their resident microbial communities ultimately determine the quantity and quality of carbon sequestered. However, environmental perturbations have been predicted to affect microbial-driven seagrass decomposition and subsequent carbon sequestration. Utilizing techniques including 16S-rDNA sequencing, solid-state NMR and microsensor profiling, we tested the hypothesis that elevated seawater temperatures and eutrophication enhance the microbial decomposition of seagrass leaf detritus and rhizome/root tissues. Nutrient additions had a negligible effect on seagrass decomposition, indicating an absence of nutrient limitation. Elevated temperatures caused a 19% higher biomass loss for aerobically decaying leaf detritus, coinciding with changes in bacterial community structure and enhanced lignocellulose degradation. Although, community shifts and lignocellulose degradation were also observed for rhizome/root decomposition, anaerobic decay was unaffected by temperature. These observations suggest that oxygen availability constrains the stimulatory effects of temperature increases on bacterial carbon remineralization, possibly through differential temperature effects on bacterial functional groups, including putative aerobic heterotrophs (e.g. Erythrobacteraceae, Hyphomicrobiaceae) and sulfate reducers (e.g. Desulfobacteraceae). Consequently, under elevated seawater temperatures, carbon accumulation rates may diminish due to higher remineralization rates at the sediment surface. Nonetheless, the anoxic conditions ubiquitous to seagrass sediments can provide a degree of carbon protection under warming seawater temperatures.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (RNA, Ribosomal, 16S); 7440-44-0 (Carbon); S88TT14065 (Oxygen)



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