Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 201
Filtrar
1.
Mar Pollut Bull ; 196: 115573, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37778243

RESUMO

Pollution is one of the main anthropogenic threats to marine ecosystems. Studies analysing the accumulation and transfer of contaminants in planktonic food webs tend to rely on samples collected in discrete water bodies. Here, we assessed the representativeness of measurements at the chlorophyll-a maximum layer during the MERITE-HIPPOCAMPE cruise for the entire water column by investigating the vertical distribution of particles and plankton obtained by in-situ optical profilers at nine stations across the Mediterranean Sea. We identified specific conditions where the interpretation of results from contaminant analyses can be improved by detailing plankton size structure and vertical distributions. First, the presence of higher than usual plankton concentrations can result in sampling issues that will affect biomass estimation within each size class and therefore bias our understanding of the contaminant dynamics. Secondly, the presence of an unsampled water layer with high zooplankton biomass might imply non-resolved contaminant pathways along the trophic structure. This study lays the basis for optimizing sampling strategy in contaminant studies.


Assuntos
Plâncton , Zooplâncton , Animais , Plâncton/química , Ecossistema , Água , Cadeia Alimentar
2.
Environ Sci Pollut Res Int ; 30(33): 81174-81188, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37314563

RESUMO

This study analyzes the distribution of nine potentially toxic trace elements (arsenic, antimony, bromine, cobalt, chromium, mercury, rubidium, selenium, and zinc) in sediments and plankton from two small mesotrophic lakes in a non-industrialized area impacted by the Caviahue-Copahue volcanic complex (CCVC). The two lakes have different plankton community structures and received different amounts of pyroclastic material after the last CCVC eruption. Trace element concentrations of surface sediments differed between lakes, according to the composition of the volcanic ashes deposited in the lakes. The size of organisms was the principal factor influencing the accumulation of most trace elements in plankton within each lake, being trace element concentrations generally higher in the microplankton than in the mesozooplankton. The planktonic biomass in the shallower lake was dominated by small algae and copepods, while mixotrophic ciliates and different-sized cladocerans dominated the deeper lake. These differences in the community structure and species composition influenced the trace element bioaccumulation, especially in microplankton, while habitat use and feeding strategies seem more relevant in mesozooplankton bioaccumulation. This work contributes to the scarce records of trace elements and their dynamics in plankton from freshwater ecosystems impacted by volcanic activity.


Assuntos
Plâncton , Oligoelementos , Plâncton/química , Lagos/química , Ecossistema , Argentina , Altitude , Monitoramento Ambiental
3.
Sci Total Environ ; 895: 165189, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37391131

RESUMO

Uptake and transformation of arsenic (As) by living organisms can alter its distribution and biogeochemical cycles in the environment. Although well known for its toxicity, several aspects of As accumulation and biological transformation by field species are still little explored. In this study, the bioaccumulation and speciation of As in phytoplankton and zooplankton from five soda lakes in the Brazilian Pantanal wetland were studied. Such lakes exhibited contrasting biogeochemical characteristics along an environmental gradient. Additionally, the influence of contrasting climatic events was assessed by collecting samples during an exceptional drought in 2017 and a flood in 2018. Total As (AsTot) content and speciation were determined using spectrometric techniques, while a suspect screening of organoarsenicals in plankton samples was carried out by high-resolution mass spectrometry. Results showed that AsTot content ranged from 16.9 to 62.0 mg kg-1 during the dry period and from 2.4 to 12.3 mg kg-1 during the wet period. The bioconcentration and bioaccumulation factors (BCF and BAF) in phytoplankton and zooplankton were found to be highly dependent on the lake typology, which is influenced by an ongoing evapoconcentration process in the region. Eutrophic and As-enriched lakes exhibited the lowest BCF and BAF values, possibly due to the formation of non-labile As complexes with organic matter or limited uptake of As by plankton caused by high salinity stress. The season played a decisive role in the results, as significantly higher BCF and BAF values were observed during the flooding event when the concentration of dissolved As in water was low. The diversity of As species was found to be dependent on the lake typology and on the resident biological community, cyanobacteria being responsible for a significant portion of As metabolism. Arsenosugars and their degradation products were detected in both phytoplankton and zooplankton, providing evidence for previously reported detoxification pathways. Although no biomagnification pattern was observed, the diet seemed to be an important exposure pathway for zooplankton.


Assuntos
Arsênio , Plâncton , Animais , Plâncton/química , Lagos/química , Arsênio/metabolismo , Bioacumulação , Salinidade , Zooplâncton/metabolismo , Fitoplâncton/metabolismo
4.
Science ; 376(6600): 1487-1491, 2022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35737766

RESUMO

Global-scale surveys of plankton communities using "omics" techniques have revolutionized our understanding of the ocean. Lipidomics has demonstrated the potential to add further essential insights on ocean ecosystem function but has yet to be applied on a global scale. We analyzed 930 lipid samples across the global ocean using a uniform high-resolution accurate-mass mass spectrometry analytical workflow, revealing previously unknown characteristics of ocean planktonic lipidomes. Focusing on 10 molecularly diverse glycerolipid classes, we identified 1151 distinct lipid species, finding that fatty acid unsaturation (i.e., number of carbon-carbon double bonds) is fundamentally constrained by temperature. We predict substantial declines in the essential fatty acid eicosapentaenoic acid over the next century, which are likely to have serious deleterious effects on economically critical fisheries.


Assuntos
Ecossistema , Ácidos Graxos Insaturados , Lipidômica , Plâncton , Temperatura , Carbono/química , Ácidos Graxos Insaturados/análise , Ácidos Graxos Insaturados/classificação , Pesqueiros , Oceanos e Mares , Plâncton/química , Plâncton/metabolismo , Espectrometria de Massas em Tandem
5.
Nature ; 589(7843): 548-553, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33505038

RESUMO

Proxy reconstructions from marine sediment cores indicate peak temperatures in the first half of the last and current interglacial periods (the thermal maxima of the Holocene epoch, 10,000 to 6,000 years ago, and the last interglacial period, 128,000 to 123,000 years ago) that arguably exceed modern warmth1-3. By contrast, climate models simulate monotonic warming throughout both periods4-7. This substantial model-data discrepancy undermines confidence in both proxy reconstructions and climate models, and inhibits a mechanistic understanding of recent climate change. Here we show that previous global reconstructions of temperature in the Holocene1-3 and the last interglacial period8 reflect the evolution of seasonal, rather than annual, temperatures and we develop a method of transforming them to mean annual temperatures. We further demonstrate that global mean annual sea surface temperatures have been steadily increasing since the start of the Holocene (about 12,000 years ago), first in response to retreating ice sheets (12 to 6.5 thousand years ago), and then as a result of rising greenhouse gas concentrations (0.25 ± 0.21 degrees Celsius over the past 6,500 years or so). However, mean annual temperatures during the last interglacial period were stable and warmer than estimates of temperatures during the Holocene, and we attribute this to the near-constant greenhouse gas levels and the reduced extent of ice sheets. We therefore argue that the climate of the Holocene differed from that of the last interglacial period in two ways: first, larger remnant glacial ice sheets acted to cool the early Holocene, and second, rising greenhouse gas levels in the late Holocene warmed the planet. Furthermore, our reconstructions demonstrate that the modern global temperature has exceeded annual levels over the past 12,000 years and probably approaches the warmth of the last interglacial period (128,000 to 115,000 years ago).


Assuntos
Aquecimento Global/história , Temperatura Alta , Camada de Gelo , Estações do Ano , Cálcio/análise , Foraminíferos/química , Efeito Estufa/história , História Antiga , Magnésio/análise , Oceano Pacífico , Plâncton/química , Reprodutibilidade dos Testes , Água do Mar/análise , Água do Mar/química
6.
Nutrients ; 14(1)2021 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-35011022

RESUMO

The aim of this study was to investigate the possible beneficial effects of exercise training (ET) with omega-3/Calanus oil supplementation on cardiorespiratory and adiposity parameters in elderly women. Fifty-five women (BMI: 19-37 kg/m2, 62-80 years old) were recruited and randomly assigned to the 4 month intervention with ET and omega-3 supplementation (Calanus oil, ET-Calanus) or ET and the placebo (sunflower oil; ET-Placebo). The body composition was determined by dual-energy X-ray absorptiometry (DXA), and cardiorespiratory parameters were measured using spiroergometry and PhysioFlow hemodynamic testing. Both interventions resulted in an increased lean mass whereas the fat mass was reduced in the leg and trunk as well as the android and gynoid regions. The content of trunk fat (in percent of the total fat) was lower and the content of the leg fat was higher in the ET-Calanus group compared with the ET-Placebo. Although both interventions resulted in similar improvements in cardiorespiratory fitness (VO2max), it was explained by an increased peripheral oxygen extraction (a-vO2diff) alone in the ET-Placebo group whereas increased values of both a-vO2diff and maximal cardiac output (COmax) were observed in the ET-Calanus group. Changes in COmax were associated with changes in systemic vascular resistance, circulating free fatty acids, and the omega-3 index. In conclusion, Calanus oil supplementation during a 4 month ET intervention in elderly women improved the cardiorespiratory function, which was due to combined central and peripheral cardiodynamic mechanisms.


Assuntos
Envelhecimento/fisiologia , Aptidão Cardiorrespiratória/fisiologia , Suplementos Nutricionais , Exercício Físico/fisiologia , Ácidos Graxos Ômega-3/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Composição Corporal , Débito Cardíaco , Feminino , Humanos , Pessoa de Meia-Idade , Plâncton/química , Resistência Vascular
7.
Bull Environ Contam Toxicol ; 104(5): 595-601, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32242255

RESUMO

Total mercury (THg) and selenium (TSe) levels were measured in stomach contents (SC) and twelve tissues of cutthroat trout (Oncorhynchus clarkii) occurring in three high-elevation lakes of Colorado, USA, inhabiting watersheds absent past and current mining activities. For 32 of 36 tissues, including muscle, mean THg wet weight (ww) concentrations were greater than in the diet (SC) for all sites, indicating biomagnification. Ranges of THg (µg/kg ww) for SC and stomach tissue (ST) were 1.23-73.54 and 14.55-61.35, respectively. Selenium concentrations in fish muscle were not greater than in the SC indicating a trophic transfer factor < 1.0. However, in several other tissues, mean Se dry weight (dw) levels were greater than in SC for all three lakes. Ranges of TSe for SC and ST were 166-7544 and 797-7523 (µg/kg dw), respectively. The muscle to egg/ovary ratio for Se averaged 2.30, 4.60, and 2.68 for the three populations. The variability of SC (planktonic vs. benthic) and differential distributions of THg and TSe in SC and organ-tissues generated questions focusing on the seasonal, physiological, and genetic drivers of these organometal(loid)s in subalpine trout.


Assuntos
Bioacumulação , Monitoramento Ambiental/métodos , Conteúdo Gastrointestinal/química , Mercúrio/metabolismo , Oncorhynchus/metabolismo , Selênio/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Colorado , Cadeia Alimentar , Lagos/química , Mercúrio/análise , Mineração , Plâncton/química , Selênio/análise , Poluentes Químicos da Água/análise
8.
J Hazard Mater ; 384: 121316, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31607578

RESUMO

In this study, Staphylococcus aureus biofilms, which are considered a foe for being pathogenic, were tested for their uranium bioremediation capacity to find out if they can turn out to be a friend. Acid phosphatase activity, which is speculated to aid in bio-precipitation of U(VI) from uranyl nitrate solution, was assayed in biofilms of seven different S. aureus strains. The presence of acid phosphatase enzyme was detected in the biofilms of all S. aureus strains (in the range of 3.1 ± 0.21 to 26.90 ± 2.32 µi.u./g), and found to be higher when compared to that of their planktonic phenotypes. Among all, S. aureus V329 biofilm showed highest biofilm formation ability along with maximum phosphatase activity (26.9 ± 2.32 µi.u./g of biomass). Addition of phosphate enhanced the U(VI) remediation when treated with uranyl nitrate solution. S. aureus V329 biofilm showed significant U tolerance with only a 3-log reduction when exposed to 10 ppm U(VI) for 1 h. When treated in batch mode, V329 biofilm successfully remediated up to 47% of the 10 ppm U(VI). This new approach using the acid phosphatase from the S. aureus V329 biofilm presents an alternative method for the remediation of uranium contamination.


Assuntos
Fosfatase Ácida/química , Biofilmes , Recuperação e Remediação Ambiental/métodos , Staphylococcus aureus/enzimologia , Urânio , Biodegradação Ambiental , Plâncton/química , Nitrato de Uranil/química
9.
Anal Bioanal Chem ; 412(3): 681-690, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31834449

RESUMO

The development of mercury (Hg) stable isotope measurements has enhanced the study of Hg sources and transformations in the environment. As a result of the mixing of inorganic Hg (iHg) and methylmercury (MeHg) species within organisms of the aquatic food web, understanding species-specific Hg stable isotopic compositions is of significant importance. The lack of MeHg isotope measurements is due to the analytical difficulty in the separation of the MeHg from the total Hg pool, with only a few methods having been tested over the past decade with varying degrees of success, and only a handful of environmentally relevant measurements. Here, we present a novel anion-exchange resin separation method using AG 1-X4 that further isolates MeHg from the sample matrix, following a distillation pretreatment, in order to obtain ambient MeHg stable isotopic compositions. This method avoids the use of organic reagents, does not require complex instrumentation, and is applicable across matrices. Separation tests across sediment, water, and biotic matrices showed acceptable recoveries (98 ± 5%, n = 54) and reproducible δ202Hg isotope results (2 SDs ≤ 0.15‰) down to 5 ng of MeHg. The measured MeHg pools in natural matrices, such as plankton and sediments, showed large deviations from the non-speciated total Hg measurement, indicating that there is an important isotopic shift during methylation that is not recorded by typical measurements, but is vital in order to assess sources of Hg during bioaccumulation. Graphical abstract.


Assuntos
Cromatografia por Troca Iônica/métodos , Monitoramento Ambiental/métodos , Compostos de Metilmercúrio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Animais , Peixes/metabolismo , Cadeia Alimentar , Sedimentos Geológicos/análise , Limite de Detecção , Isótopos de Mercúrio/análise , Isótopos de Mercúrio/isolamento & purificação , Compostos de Metilmercúrio/análise , Plâncton/química , Poluentes Químicos da Água/análise
10.
J Biol Chem ; 295(2): 504-516, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31771981

RESUMO

Peptidoglycan (PG) is a critical component of the bacterial cell wall and is composed of a repeating ß-1,4-linked disaccharide of N-acetylglucosamine and N-acetylmuramic acid appended with a highly conserved stem peptide. In Gram-negative bacteria, PG is assembled in the cytoplasm and exported into the periplasm where it undergoes considerable maturation, modification, or degradation depending on the growth phase or presence of environmental stressors. These modifications serve important functions in diverse processes, including PG turnover, cell elongation/division, and antibiotic resistance. Conventional methods for analyzing PG composition are complex and time-consuming. We present here a streamlined MS-based method that combines differential analysis with statistical 1D annotation approaches to quantitatively compare PGs produced in planktonic- and biofilm-cultured Pseudomonas aeruginosa We identified a core assembly of PG that is present in high abundance and that does not significantly differ between the two growth states. We also identified an adaptive PG assembly that is present in smaller amounts and fluctuates considerably between growth states in response to physiological changes. Biofilm-derived adaptive PG exhibited significant changes compared with planktonic-derived PG, including amino acid substitutions of the stem peptide and modifications that indicate changes in the activity of amidases, deacetylases, and lytic transglycosylases. The results of this work also provide first evidence of de-N-acetylated muropeptides from P. aeruginosa The method developed here offers a robust and reproducible workflow for accurately determining PG composition in samples that can be used to assess global PG fluctuations in response to changing growth conditions or external stimuli.


Assuntos
Biofilmes , Peptidoglicano/metabolismo , Plâncton/fisiologia , Pseudomonas aeruginosa/fisiologia , Biofilmes/crescimento & desenvolvimento , Parede Celular/química , Parede Celular/metabolismo , Glicômica , Humanos , Espectrometria de Massas , Peptidoglicano/química , Plâncton/química , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/química
11.
Dokl Biochem Biophys ; 487(1): 256-259, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31559592

RESUMO

The effect of aqueous unmodified fullerene C60 dispersions (AFD) at a concentration of 5 mg/L on the total number and metabolic activity of heterotrophic river bacteroplankton was investigated. The stimulating effect of AFD on the number of bacterioplankton and on the activity of electron transport chains in its cells is shown. It is established that, in the presence of AFD, the bactericidal activity of antibiotics decreases. The stimulating effect of fullerene on the natural heterotrophic bacterioplankton, which we discovered, casts doubt on the expediency of using AFD as a bacteriostatic agent.


Assuntos
Fulerenos/química , Plâncton/química , Plâncton/microbiologia , Água/química , Cinética
12.
Chemosphere ; 237: 124430, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31369904

RESUMO

Coastal environment are often stress from petroleum-derived hydrocarbon pollution. However, petroleum-derived hydrocarbon is persistent organic pollutants and their biodegradation by phytoplankton is little known. Five species of marine phytoplankton, including Dunaliella salina, Chlorella sp., Conticribra weissflogii, Phaeodactylum tricornutum Bohlin, and Prorocentrum donghaiense, have been used to test their tolerance to petroleum hydrocarbon contamination. D.salina and Chlorella sp can survive in high levels of No. 0 diesel oils water-soluble fractions (WSFs, 5.0 mg L-1), furthermore, petroleum hydrocarbon could be biodegraded effectively by them (Fig. 2). The content of ß-carotene in these two species of phytoplankton has significant correlation with degradation rate of WSFs concentrations (Fig. 4), petroleum hydrocarbons could be biodegraded effectively by algae. Meanwhile, the ·OH in seawater can be removed by ß-carotene effectively so that algal cells could be protected by the ß-carotene for its strong antioxidant capacity. Therefore, ß-carotene as a coin has two sides on the degradation of WSFs. Here we explore the relationship between plankton-based ß-carotene and biodegradable adaptabllity to petroleum-derived hydrocarbon, which offers a green technology for petroleum-derived hydrocarbon treatment.


Assuntos
Biodegradação Ambiental , Hidrocarbonetos/metabolismo , Fitoplâncton/química , beta Caroteno/análise , Petróleo , Poluição por Petróleo/prevenção & controle , Plâncton/química , Plâncton/metabolismo , Água do Mar/química , Solubilidade
13.
Chemosphere ; 235: 690-700, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31279119

RESUMO

Mercury (Hg) is known as one of the major contaminants in the Amazon. The Tapajós River basin, in the Brazilian Amazon, has diverse anthropogenic activities which increase Hg concentrations in the aquatic ecosystem. Moreover, high concentrations of Hg are naturally found in this basin. Distribution of total (THg) and methyl (MeHg) mercury were assessed in unfiltered water (n = 47), suspended particulate matter (SPM, n = 30), superficial sediment (BS, n = 29), plankton (n = 28) and fishes (n = 129) from the Tapajós River basin. Suspended particles were the main carrier of Hg in the water column and sediment. Increased erosion, prompted by anthropic activities, led to higher Hg concentrations in water from the most impacted areas. Hg is transported mainly in particulate matter; thus, anthropic disturbances influence Hg concentrations downstream. Limnological parameters such as organic matter content influenced MeHg concentrations in water, plankton and sediment of the Tapajós basin. Hg methylation in total plankton was more efficient in lakes (13-66%) than in Tapajós River main channel (2-14%). Biotic and abiotic factors interact in a complex way in the aquatic ecosystem, making Hg concentrations to vary in food web. Gold mining and deforestation probably increase Hg levels in the Tapajós basin. Thus, in addition to Hg monitoring, prevention and remediation efforts should be focused on soil and sediment erosion control.


Assuntos
Monitoramento Ambiental , Compostos de Metilmercúrio/análise , Poluentes Químicos da Água/análise , Animais , Brasil , Ecossistema , Peixes/metabolismo , Cadeia Alimentar , Lagos , Mercúrio/análise , Compostos de Metilmercúrio/metabolismo , Mineração , Plâncton/química , Rios/química , Alimentos Marinhos , Solo , Água , Poluentes Químicos da Água/metabolismo
14.
Environ Pollut ; 252(Pt A): 666-674, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31185355

RESUMO

The influence of trophic status on the distribution of hydrophobic organic contaminants (HOCs) in different subtropical shallow waters at large spatial scales remains largely unknown. In this study, samples of surface sediments, water, total suspended particles, phytoplankton, and zooplankton were simultaneously collected from 83 sampling sites in 20 subtropical oligotrophic to hyper-eutrophic shallow lakes in China to investigate the influence of trophic status on the spatial distribution and sinking fluxes of 16 polycyclic aromatic hydrocarbons (PAHs). The total concentration of the 16 PAHs (ΣPAH16) in the water columns of these lakes varied from 0.22 to 5.81 µg L-1, and increased with the trophic state index (TSI) and phytoplankton biomass. Phytoplankton were the dominant reservoir for the PAHs in the water column. However, the fraction of ΣPAH16 in phytoplankton decreased with the TSI. The average sinking flux of ΣPAH16 of the individual lakes varied from 2257.1 to 261674.1 mg m-2 d-1, and increased with the TSI of the lakes. The concentration of ΣPAH16 in the surface sediments ranged from 385.77 to 3784.37 ng gdw-1, and increased with the TSI and the ratio of phycocyanin/sediment organic carbon. It suggested that cyanobacterial biomass affected by trophic status dominated the occurrence of the PAHs in the surface sediments of these lakes. Biomass dilution and the biological pump affected the accumulation of the PAHs in phytoplankton, and zooplankton, and had more influence on the PAHs with higher hydrophobicity. Both the bioconcentration factors and bioaccumulation factors of the PAHs decreased with the TSI. No biomagnification was observed for the PAHs from phytoplankton to zooplankton in these lakes in spring. Our study provided novel knowledge for the coupling between eutrophication and HOCs in 20 subtropical shallow lakes with different trophic status.


Assuntos
Monitoramento Ambiental , Lagos/química , Plâncton/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Animais , Biomassa , China , Cianobactérias , Eutrofização , Cadeia Alimentar , Sedimentos Geológicos/química , Fitoplâncton , Estações do Ano , Zooplâncton
16.
Sci Rep ; 9(1): 533, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30679608

RESUMO

This study provides evidence that ambient seawater density influences calcification and may account for the observed planktonic foraminifera shell mass increase during glacial times. Volumes of weighed fossil Globigerina bulloides shells were accurately determined using X-ray Computer Tomography and were combined with water density reconstructions from Mg/Ca and δ18O measurements to estimate the buoyancy force exerted on each shell. After assessment of dissolution effects, the resulting relationship between shell mass and buoyancy suggests that heavier shells would need to be precipitated in glacial climates in order for these organisms to remain at their optimum living depth, and counterbalance the increased buoyant force of a denser, glacial ocean. Furthermore, the reanalysis of bibliographic data allowed the determination of a relationship between G. bulloides shell mass and ocean density, which introduces implications of a negative feedback mechanism for the uptake of atmospheric CO2 by the oceans.


Assuntos
Calcificação Fisiológica , Foraminíferos/fisiologia , Fósseis , Plâncton/fisiologia , Cálcio/análise , Clima , Foraminíferos/química , Fósseis/anatomia & histologia , Magnésio/análise , Oceanos e Mares , Isótopos de Oxigênio/análise , Plâncton/química , Água do Mar/análise , Temperatura
17.
Nat Prod Rep ; 36(8): 1093-1116, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-30620039

RESUMO

Covering: January 2015 through December 2017 This review focuses on recent studies on the chemical ecology of planktonic marine ecosystems, with the objective of presenting a comprehensive overview of new findings in the field in the time period covered. In order to highlight the role of chemically mediated interactions in the marine plankton this review has been organized by ecological concepts starting with intraspecific communication, followed by interspecific interactions (including facilitation and mutualism, host-parasite, allelopathy, and predator-prey), and finally the effects of plankton secondary metabolites on community and ecosystem-wide interactions.


Assuntos
Ecologia , Plâncton/fisiologia , Animais , Organismos Aquáticos , Ecossistema , Interações Hospedeiro-Parasita , Estrutura Molecular , Plâncton/química , Comportamento Predatório , Percepção de Quorum
18.
Colloids Surf B Biointerfaces ; 173: 639-646, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30368211

RESUMO

Bacterial adhesion is a key step to prevent environmental problems called acid mine drainage or to improve leaching efficiency in industry, since it initiates and enhances bioleaching. Thus, to analyze bacterial adhesion and to understand this process is crucial. In this study atomic force microscopy equipped with a pyrite or chalcopyrite tip was applied to study the adhesion of Sulfobacillus thermosulfidooxidans. The results illustrate that planktonic cells of both pyrite- and sulfur-grown cells of S. thermosulfidooxidans show more affinity to pyrite than to chalcopyrite (adhesion forces 2 nN versus 0.13 nN). However, the interactions between bacteria and chalcopyrite can be strengthened, if the bacteria are brought into contact with the chalcopyrite. The biofilm cells show low affinity to either pyrite or chalcopyrite. A high content of proteins in the extracellular polymeric substances collected from planktonic cells of S. thermosulfidooxidans and a low content of proteins collected from biofilm EPS indicates that proteins play an important role in initial adhesion. Analysis of adhesion force-distance curves reveal that adhesion by pyrite-grown cells is a complex interaction involving several bonding forces.


Assuntos
Proteínas de Bactérias/química , Clostridiales/química , Cobre/química , Matriz Extracelular de Substâncias Poliméricas/química , Ferro/química , Plâncton/química , Sulfetos/química , Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Clostridiales/citologia , Clostridiales/fisiologia , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Plâncton/crescimento & desenvolvimento , Eletricidade Estática , Propriedades de Superfície
19.
J Mater Chem B ; 7(17): 2771-2781, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32255079

RESUMO

Bacterial infections are one of the leading causes of disease worldwide. Conventional antibiotics are becoming less efficient, due to antibiotic-resistant bacterial strains. Therefore, the development of novel antibacterial materials and advanced treatment strategies are becoming increasingly important. In the present work, we developed a simple and efficient strategy for effective bacterial capture and their subsequent eradication through photothermal killing. The developed device consists of a flexible nanoheater, comprising a Kapton/Au nanoholes substrate, coated with reduced graphene oxide-polyethyleneimine (K/Au NH/rGO-PEI) thin films. The Au NH plasmonic structure was tailored to feature strong absorption in the near-infrared (NIR) region, where most biological matter has limited absorption, while PEI was investigated for its strong binding with bacteria through electrostatic interactions. The K/Au NH/rGO-PEI device was demonstrated to capture and eliminate effectively both planktonic Gram-positive Staphilococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria after 10 min of NIR (980 nm) irradiation and, to destroy and eradicate Staphilococcus epidermidis (S. epidermidis) biofilms after 30 min irradiation. The technique developed herein is simple and universal with potential applications for eradication of different micro-organisms.


Assuntos
Bactérias/química , Grafite/química , Plâncton/química , Polietilenoimina/química , Biofilmes , Humanos
20.
Harmful Algae ; 80: 15-34, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30502808

RESUMO

Azaspiracids (AZA) are a group of lipophilic polyether compounds which have been implicated in shellfish poisoning incidents around Europe. They are produced by a few species of the dinophycean genera Azadinium and Amphidoma (Amphidomataceae). The presence of AZA toxins in Norway is well documented, but knowledge of the distribution and diversity of Azadinium and other Amphidomataceae along the Norwegian coast is rather limited and poorly documented. On a research survey along the Norwegian coast in 2015 from the Skagerrak in the South to Trondheimsfjorden in the North, plankton samples from 67 stations were analysed for the presence of Azadinium and Amphidoma and their respective AZA by on-board live microscopy, real-time PCR assays specific for Amphidomataceae, and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Microscopy using live samples and positive real-time PCR assays using a general family probe and two species specific probes revealed the presence of Amphidomataceae distributed throughout the sampling area. Overall abundance was low, however, and was in agreement with a lack of detectable AZA in plankton samples. Single cell isolation and morphological and molecular characterisation of established strains revealed the presence of 7 amphidomatacean species (Azadiniun spinosum, Az. poporum, Az. obesum, Az. dalianense, Az. trinitatum, Az. polongum, Amphidoma languida) in the area. Azaspiracids were produced by the known AZA producing species Az. spinosum, Az. poporum and Am. languida only. LC-MS/MS analysis further revealed that Norwegian strains produce previously unreported AZA for Norway (AZA-11 by Az. spinosum, AZA-37 by Az. poporum, AZA-38 and AZA-39 by Am. languida), and also four novel compounds (AZA-50, -51 by Az. spinosum, AZA-52, -53 by Am. languida), whose structural properties are described and which now can be included in existing analytical protocols. A maximum likelihood analysis of concatenated rDNA regions (SSU, ITS1-ITS2, partial LSU) showed that the strains of Az. spinosum fell in two well supported clades, where most but not all new Norwegian strains formed the new Ribotype B. Ribotype differentiation was supported by a minor morphological difference with respect to the presence/absence of a rim around the pore plate, and was consistently reflected by different AZA profiles. Strains of Az. spinosum from ribotype A produce AZA-1, -2 and -33, whereas the new strains of ribotype B produce mainly AZA-11 and AZA-51. Significant sequence differences between both Az. spinosum ribotypes underline the need to redesign the currently used qPCR probes in order to detect all AZA producing Az. spinosum. The results generally underline the conclusion that for the Norwegian coast area it is important that amphidomatacean species are taken into account in future studies and monitoring programs.


Assuntos
Dinoflagellida/química , Monitoramento Ambiental , Toxinas Marinhas/análise , Plâncton/química , Compostos de Espiro/análise , Biodiversidade , Cromatografia Líquida , Demografia , Noruega , Densidade Demográfica , Espectrometria de Massas em Tandem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...