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1.
N Engl J Med ; 387(11): 967-977, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-36018037

RESUMO

BACKGROUND: A polypill that includes key medications associated with improved outcomes (aspirin, angiotensin-converting-enzyme [ACE] inhibitor, and statin) has been proposed as a simple approach to the secondary prevention of cardiovascular death and complications after myocardial infarction. METHODS: In this phase 3, randomized, controlled clinical trial, we assigned patients with myocardial infarction within the previous 6 months to a polypill-based strategy or usual care. The polypill treatment consisted of aspirin (100 mg), ramipril (2.5, 5, or 10 mg), and atorvastatin (20 or 40 mg). The primary composite outcome was cardiovascular death, nonfatal type 1 myocardial infarction, nonfatal ischemic stroke, or urgent revascularization. The key secondary end point was a composite of cardiovascular death, nonfatal type 1 myocardial infarction, or nonfatal ischemic stroke. RESULTS: A total of 2499 patients underwent randomization and were followed for a median of 36 months. A primary-outcome event occurred in 118 of 1237 patients (9.5%) in the polypill group and in 156 of 1229 (12.7%) in the usual-care group (hazard ratio, 0.76; 95% confidence interval [CI], 0.60 to 0.96; P = 0.02). A key secondary-outcome event occurred in 101 patients (8.2%) in the polypill group and in 144 (11.7%) in the usual-care group (hazard ratio, 0.70; 95% CI, 0.54 to 0.90; P = 0.005). The results were consistent across prespecified subgroups. Medication adherence as reported by the patients was higher in the polypill group than in the usual-care group. Adverse events were similar between groups. CONCLUSIONS: Treatment with a polypill containing aspirin, ramipril, and atorvastatin within 6 months after myocardial infarction resulted in a significantly lower risk of major adverse cardiovascular events than usual care. (Funded by the European Union Horizon 2020; SECURE ClinicalTrials.gov number, NCT02596126; EudraCT number, 2015-002868-17.).


Assuntos
Inibidores da Enzima Conversora de Angiotensina , Doenças Cardiovasculares , Inibidores de Hidroximetilglutaril-CoA Redutases , Inibidores da Agregação Plaquetária , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Aspirina/efeitos adversos , Aspirina/uso terapêutico , Atorvastatina/efeitos adversos , Atorvastatina/uso terapêutico , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/mortalidade , Doenças Cardiovasculares/prevenção & controle , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , AVC Isquêmico/prevenção & controle , Infarto do Miocárdio/complicações , Infarto do Miocárdio/prevenção & controle , Infarto do Miocárdio/terapia , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/uso terapêutico , Ramipril/efeitos adversos , Ramipril/uso terapêutico , Prevenção Secundária/métodos
2.
PLoS Biol ; 20(12): e3001921, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36548240

RESUMO

Antarctic terrestrial biodiversity faces multiple threats, from invasive species to climate change. Yet no large-scale assessments of threat management strategies exist. Applying a structured participatory approach, we demonstrate that existing conservation efforts are insufficient in a changing world, estimating that 65% (at best 37%, at worst 97%) of native terrestrial taxa and land-associated seabirds are likely to decline by 2100 under current trajectories. Emperor penguins are identified as the most vulnerable taxon, followed by other seabirds and dry soil nematodes. We find that implementing 10 key threat management strategies in parallel, at an estimated present-day equivalent annual cost of US$23 million, could benefit up to 84% of Antarctic taxa. Climate change is identified as the most pervasive threat to Antarctic biodiversity and influencing global policy to effectively limit climate change is the most beneficial conservation strategy. However, minimising impacts of human activities and improved planning and management of new infrastructure projects are cost-effective and will help to minimise regional threats. Simultaneous global and regional efforts are critical to secure Antarctic biodiversity for future generations.


Assuntos
Conservação dos Recursos Naturais , Spheniscidae , Animais , Humanos , Regiões Antárticas , Biodiversidade , Espécies Introduzidas , Mudança Climática , Ecossistema
3.
Eur Heart J ; 44(29): 2698-2709, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37339167

RESUMO

AIMS: Epigenetic age is emerging as a personalized and accurate predictor of biological age. The aim of this article is to assess the association of subclinical atherosclerosis with accelerated epigenetic age and to investigate the underlying mechanisms mediating this association. METHODS AND RESULTS: Whole blood methylomics, transcriptomics, and plasma proteomics were obtained for 391 participants of the Progression of Early Subclinical Atherosclerosis study. Epigenetic age was calculated from methylomics data for each participant. Its divergence from chronological age is termed epigenetic age acceleration. Subclinical atherosclerosis burden was estimated by multi-territory 2D/3D vascular ultrasound and by coronary artery calcification. In healthy individuals, the presence, extension, and progression of subclinical atherosclerosis were associated with a significant acceleration of the Grim epigenetic age, a predictor of health and lifespan, regardless of traditional cardiovascular risk factors. Individuals with an accelerated Grim epigenetic age were characterized by an increased systemic inflammation and associated with a score of low-grade, chronic inflammation. Mediation analysis using transcriptomics and proteomics data revealed key pro-inflammatory pathways (IL6, Inflammasome, and IL10) and genes (IL1B, OSM, TLR5, and CD14) mediating the association between subclinical atherosclerosis and epigenetic age acceleration. CONCLUSION: The presence, extension, and progression of subclinical atherosclerosis in middle-aged asymptomatic individuals are associated with an acceleration in the Grim epigenetic age. Mediation analysis using transcriptomics and proteomics data suggests a key role of systemic inflammation in this association, reinforcing the relevance of interventions on inflammation to prevent cardiovascular disease.


Assuntos
Aterosclerose , Doença da Artéria Coronariana , Pessoa de Meia-Idade , Humanos , Multiômica , Aterosclerose/genética , Inflamação/genética , Epigênese Genética , Fatores de Risco
4.
Childs Nerv Syst ; 35(11): 2227-2231, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31079180

RESUMO

Neurenteric cysts are rare developmental lesions typically found outside the central nervous system but when they do, we most likely find them in a spinal (cervical or dorsal) intradural extramedular location, often associated with dysraphism. The more unusual intracranial cases have been published because of its rarity, occurring mostly as a posterior fossa extra-axial cyst, in adults. Supratentorial cases are distinctly infrequent, especially in children, resulting in few case reports and even fewer case reviews. We describe a case of a child with a supratentorial neurenteric cyst and present a brief review of the literature about these cysts in children, a noticeable gap in the literature.


Assuntos
Lobo Frontal/cirurgia , Defeitos do Tubo Neural/cirurgia , Adolescente , Imagem de Difusão por Ressonância Magnética , Lobo Frontal/anormalidades , Lobo Frontal/diagnóstico por imagem , Humanos , Masculino , Defeitos do Tubo Neural/complicações , Defeitos do Tubo Neural/diagnóstico por imagem , Procedimentos Neurocirúrgicos/métodos , Convulsões/etiologia
5.
Acta Neurochir (Wien) ; 161(2): 351-354, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30617713

RESUMO

Choroid plexus tumors (CPT) can present in the baseline magnetic resonance imaging (MRI) with lesions compatible with leptomeningeal dissemination. Therapeutic strategy in this condition is controversial. We present a case of an infant with CPP and significant diffuse leptomeningeal contrast enhancement at diagnosis, which spontaneously resolved after removal of the primary tumor. In these challenging cases, several aspects, such as histopathological/molecular diagnosis and close radiological follow-up, should be taken into account to avoid unnecessary treatments.


Assuntos
Neoplasias Meníngeas/diagnóstico por imagem , Papiloma do Plexo Corióideo/diagnóstico por imagem , Plexo Corióideo/diagnóstico por imagem , Plexo Corióideo/patologia , Diagnóstico Diferencial , Feminino , Humanos , Lactente , Imageamento por Ressonância Magnética , Meninges/diagnóstico por imagem , Meninges/patologia , Papiloma do Plexo Corióideo/patologia , Papiloma do Plexo Corióideo/cirurgia
6.
Childs Nerv Syst ; 33(5): 849-852, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28251325

RESUMO

Diffuse intrinsic pontine glioma (DIPG) is an aggressive infiltrative glioma for which no curative therapy is available. Radiation therapy (RT) is the only potentially effective intervention in delaying tumor progression, but only transiently. At progression, re-irradiation is gaining popularity as an effective palliative therapy. However, at second progression, exclusive symptomatic treatment is usually offered. Here we report two patients with DIPG at second progression who were treated with a second re-irradiation course with good response. Importantly, treatment was well tolerated with no irradiation associated acute toxicity identified.


Assuntos
Neoplasias do Tronco Encefálico/radioterapia , Progressão da Doença , Glioma/radioterapia , Reirradiação/métodos , Neoplasias do Tronco Encefálico/diagnóstico por imagem , Criança , Pré-Escolar , Feminino , Glioma/diagnóstico por imagem , Humanos , Masculino
7.
Mar Drugs ; 15(7)2017 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-28737704

RESUMO

Cyanotoxins are secondary metabolites produced by cyanobacteria, of varied chemical nature and toxic effects. Although cyanobacteria thrive in all kinds of ecosystems on Earth even under very harsh conditions, current knowledge on cyanotoxin distribution is almost restricted to freshwaters from temperate latitudes. In this review, we bring to the forefront the presence of cyanotoxins in extreme environments. Cyanotoxins have been reported especially in polar deserts (both from the Arctic and Antarctica) and alkaline lakes, but also in hot deserts, hypersaline environments, and hot springs. Cyanotoxins detected in these ecosystems include neurotoxins-anatoxin-a, anatoxin-a (S), paralytic shellfish toxins, ß-methylaminopropionic acid, N-(2-aminoethyl) glycine and 2,4-diaminobutyric acid- and hepatotoxins -cylindrospermopsins, microcystins and nodularins-with microcystins being the most frequently reported. Toxin production there has been linked to at least eleven cyanobacterial genera yet only three of these (Arthrospira, Synechococcus and Oscillatoria) have been confirmed as producers in culture. Beyond a comprehensive analysis of cyanotoxin presence in each of the extreme environments, this review also identifies the main knowledge gaps to overcome (e.g., scarcity of isolates and -omics data, among others) toward an initial assessment of ecological and human health risks in these amazing ecosystems developing at the very edge of life.


Assuntos
Toxinas Bacterianas/metabolismo , Toxinas Marinhas/metabolismo , Microcistinas/metabolismo , Animais , Regiões Antárticas , Regiões Árticas , Cianobactérias/metabolismo , Toxinas de Cianobactérias , Ecologia , Ecossistema , Ambientes Extremos , Humanos
9.
Environ Sci Technol ; 49(3): 1611-20, 2015 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-25565212

RESUMO

Cyanobacteria are Gram-negative photosynthetic prokaryotes that are widespread on Earth. Eutrophication and global warming make some aquatic ecosystems behave as bioreactors that trigger rapid and massive cyanobacterial growth with remarkable economic and health consequences. Rapid and efficient early warning systems are required to support decisions by water body authorities. We have produced 17 specific antibodies to the most frequent cyanobacterial strains blooming in freshwater ecosystems, some of which are toxin producers. A sandwich-type antibody microarray immunoassay (CYANOCHIP) was developed for the simultaneous testing of any of the 17 strains, or other closely related strains, in field samples from different habitats (water, rocks, and sediments). We titrated and tested all of the antibodies in succession using a fluorescent sandwich microarray immunoassay. Although most showed high specificity, we applied a deconvolution method based on graph theory to disentangle the few existing cross-reactions. The CYANOCHIP sensitivity ranged from 10(2) to 10(4) cells mL(-1), with most antibodies detecting approximately 10(2) cells mL(-1). We validated the system by testing multiple isolates and crude natural samples from freshwater reservoirs and rocks, both in the laboratory and by in situ testing in the field. The results demonstrated that CYANOCHIP is a valuable tool for the sensitive and reliable detection of cyanobacteria for early warning and research purposes.


Assuntos
Cianobactérias , Água Doce/microbiologia , Análise em Microsséries/métodos , Anticorpos , Cianobactérias/classificação , Cianobactérias/imunologia , Ecossistema , Monitoramento Ambiental/métodos , Eutrofização , Imunoensaio/métodos , Reprodutibilidade dos Testes , Espanha , Microbiologia da Água
10.
Appl Environ Microbiol ; 80(4): 1359-70, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24334673

RESUMO

Planktonic Nostocales cyanobacteria represent a challenge for microbiological research because of the wide range of cyanotoxins that they synthesize and their invasive behavior, which is presumably enhanced by global warming. To gain insight into the phylogeography of potentially toxic Nostocales from Mediterranean Europe, 31 strains of Anabaena (Anabaena crassa, A. lemmermannii, A. mendotae, and A. planctonica), Aphanizomenon (Aphanizomenon gracile, A. ovalisporum), and Cylindrospermopsis raciborskii were isolated from 14 freshwater bodies in Spain and polyphasically analyzed for their phylogeography, cyanotoxin production, and the presence of cyanotoxin biosynthesis genes. The potent cytotoxin cylindrospermopsin (CYN) was produced by all 6 Aphanizomenon ovalisporum strains at high levels (5.7 to 9.1 µg CYN mg(-1) [dry weight]) with low variation between strains (1.5 to 3.9-fold) and a marked extracellular release (19 to 41% dissolved CYN) during exponential growth. Paralytic shellfish poisoning (PSP) neurotoxins (saxitoxin, neosaxitoxin, and decarbamoylsaxitoxin) were detected in 2 Aphanizomenon gracile strains, both containing the sxtA gene. This gene was also amplified in non-PSP toxin-producing Aphanizomenon gracile and Aphanizomenon ovalisporum. Phylogenetic analyses supported the species identification and confirmed the high similarity of Spanish Anabaena and Aphanizomenon strains with other European strains. In contrast, Cylindrospermopsis raciborskii from Spain grouped together with American strains and was clearly separate from the rest of the European strains, raising questions about the current assumptions of the phylogeography and spreading routes of C. raciborskii. The present study confirms that the nostocalean genus Aphanizomenon is a major source of CYN and PSP toxins in Europe and demonstrates the presence of the sxtA gene in CYN-producing Aphanizomenon ovalisporum.


Assuntos
Cianobactérias/classificação , Cianobactérias/genética , Água Doce/microbiologia , Toxinas Marinhas/metabolismo , Filogeografia , Uracila/análogos & derivados , Alcaloides , Toxinas Bacterianas , Cianobactérias/metabolismo , Toxinas de Cianobactérias , DNA Bacteriano/classificação , DNA Bacteriano/genética , Dados de Sequência Molecular , Análise de Sequência de DNA , Espanha , Uracila/metabolismo
11.
Front Microbiol ; 15: 1350457, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38646624

RESUMO

Antarctica is one of the most outstanding analogs of Mars, and cyanobacterial mats are considered one of the most resilient biological consortia. The purpose of this study is to find out the effect of the Martian conditions on an Antarctic cyanobacterial mat. We exposed an Antarctic microbial mat to Martian conditions in a simulating chamber (MARTE) for 15 d and investigated the variations in the consortium by the use of 16S rRNA gene expression as an indicator of the biological activity. Metabarcoding using the V3-V4 regions of the 16S rRNA gene was used to determine the succession of the active members of the microbial consortium during the experiment. The results showed that the microbial mat, far from collapsing, can survive the stringent conditions in the simulating chamber. Different behaviors were displayed depending on the metabolic capabilities and physiological characteristics of every taxon. The main conclusion is that the Martian conditions did not impair growth in some of the groups, and thus, the investigated Antarctic community would be able to survive in a Martian environment at least during the short experimental period, although elements of the community were affected in different ways.

12.
Sci Total Environ ; 932: 172741, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38679105

RESUMO

Cyanobacteria are major contributors to algal blooms in inland waters, threatening ecosystem function and water uses, especially when toxin-producing strains dominate. Here, we examine 140 hyperspectral (HS) images of five representatives of the widespread, potentially toxin-producing and bloom-forming genera Microcystis, Planktothrix, Aphanizomenon, Chrysosporum and Dolichospermum, to determine the potential of utilizing visible and near-infrared (VIS/NIR) reflectance for their discrimination. Cultures were grown under various light and nutrient conditions to induce a wide range of pigment and spectral variability, mimicking variations potentially found in natural environments. Importantly, we assumed a simplified scenario where all spectral variability was derived from cyanobacteria. Throughout the cyanobacterial life cycle, multiple HS images were acquired along with extractions of chlorophyll a and phycocyanin. Images were calibrated and average spectra from the region of interest were extracted using k-means algorithm. The spectral data were pre-processed with seven methods for subsequent integration into Random Forest models, whose performances were evaluated with different metrics on the training, validation and testing sets. Successful classification rates close to 90 % were achieved using either the first or second derivative along with spectral smoothing, identifying important wavelengths in both the VIS and NIR. Microcystis and Chrysosporum were the genera achieving the highest accuracy (>95 %), followed by Planktothrix (79 %), and finally Dolichospermum and Aphanizomenon (>50 %). The potential of HS imagery to discriminate among toxic cyanobacteria is discussed in the context of advanced monitoring, aiming to enhance remote sensing capabilities and risk predictions for water bodies affected by cyanobacterial harmful algal blooms.


Assuntos
Cianobactérias , Monitoramento Ambiental , Eutrofização , Aprendizado de Máquina , Cianobactérias/crescimento & desenvolvimento , Monitoramento Ambiental/métodos , Imageamento Hiperespectral/métodos , Proliferação Nociva de Algas
13.
Sci Rep ; 14(1): 9731, 2024 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-38679613

RESUMO

Cyanobacteria inhabiting extreme environments constitute a promising source for natural products with biotechnological applications. However, they have not been studied in-depth for this purpose due to the difficulties in their isolation and mass culturing. The Atacama Desert suffers one of the highest solar irradiances that limits the presence of life on its hyperarid core to endolithic microbial communities supported by cyanobacteria as primary producers. Some of these cyanobacteria are known to produce scytonemin, a UV-screening liposoluble pigment with varied biotechnological applications in cosmetics and other industries. In this work we carried out a strain selection based on growth performance among 8 endolithic cyanobacteria of the genera Chroococcidiopsis, Gloeocapsa and Gloeocapsopsis isolated from non-saline rocks of the Atacama Desert. Then we investigated the influence of NaCl exposure on scytonemin production yield. Results in the selected strain (Chroococcidiopsis sp. UAM571) showed that rising concentrations of NaCl lead to a growth decrease while triggering a remarkable increase in the scytonemin content, reaching maximum values at 20 g L-1 of NaCl over 50-fold higher scytonemin contents than those obtained without NaCl. Altogether, these findings point out to cyanobacteria from the Atacama Desert as potentially suitable candidates for pilot-scale cultivation with biotechnological purposes, particularly to obtain scytonemin.


Assuntos
Cianobactérias , Clima Desértico , Indóis , Salinidade , Cianobactérias/metabolismo , Cianobactérias/crescimento & desenvolvimento , Indóis/metabolismo , Fenóis/metabolismo
14.
Biodivers Data J ; 12: e106199, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38344169

RESUMO

Background: Incomplete species inventories for Antarctica represent a key challenge for comprehensive ecological research and conservation in the region. Additionally, data required to understand population dynamics, rates of evolution, spatial ranges, functional traits, physiological tolerances and species interactions, all of which are fundamental to disentangle the different functional elements of Antarctic biodiversity, are mostly missing. However, much of the fauna, flora and microbiota in the emerged ice-free land of the continent have an uncertain presence and/or unresolved status, with entire biodiversity compendia of prokaryotic groups (e.g. bacteria) being missing. All the available biodiversity information requires consolidation, cross-validation, re-assessment and steady systematic inclusion in order to create a robust catalogue of biodiversity for the continent. New information: We compiled, completed and revised eukaryotic species inventories present in terrestrial and freshwater ecosystems in Antarctica in a new living database: terrANTALife (version 1.0). The database includes the first integration in a compendium for many groups of eukaryotic microorganisms. We also introduce a first catalogue of amplicon sequence variants (ASVs) of prokaryotic biodiversity. Available compendia and literature to date were searched for Antarctic terrestrial and freshwater species, integrated, taxonomically harmonised and curated by experts to create comprehensive checklists of Antarctic organisms. The final inventories comprises 470 animal species (including vertebrates, free-living invertebrates and parasites), 306 plants (including all Viridiplantae: embryophytes and green algae), 997 fungal species and 434 protists (sensu lato). We also provide a first account for many groups of microorganisms, including non-lichenised fungi and multiple groups of eukaryotic unicellular species (Stramenophila, Alveolata and Rhizaria (SAR), Chromists and Amoeba), jointly referred to as "protists". In addition, we identify 1753 bacterial (obtained from 348117 ASVs) and 34 archaeal genera (from 1848 ASVs), as well as, at least, 14 virus families. We formulate a basic tree of life in Antarctica with the main lineages listed in the region and their "known-accepted-species" numbers.

15.
Microb Ecol ; 65(1): 12-21, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22915156

RESUMO

Aphanizomenon ovalisporum is a planktonic nostocalean cyanobacterium with increasing research interest due to its ability to produce the potent cytotoxin cylindrospermopsin and its potential invasiveness under the global warming scenario. The present study provides novel data on the potential dispersal strategies of A. ovalisporum by analyzing the influence of temperature (10-40 °C) on akinete differentiation and cell morphometry in cultures of A. ovalisporum UAM 290 isolated from a Spanish pond. Our results confirmed a temperature-dependent akinete differentiation, with the maximum akinete production reached at 20 °C (15 % of the cells), a low basal production at 25-30 °C (<0.4 % of the cells) and no detectable production at 35 °C. Furthermore, we reported the fragmentation of A. ovalisporum filaments at temperatures of 25 °C and above. Additionally, we observed that the morphology of vegetative cells varied under different temperature scenarios. Indeed, a strong negative correlation was found between temperature and the width, length and biovolume of vegetative cells, whereas akinete dimensions remained stable along the temperature gradient. Therefore, linear regressions between temperature and the cell size parameters are herein presented aiming to facilitate the identification of A. ovalisporum in the field throughout the course of the year. This is the first study evidencing that akinete production is triggered by temperatures between 20 and 25 °C in A. ovalisporum and reporting the existence of filament fragmentation as a potential dispersal strategy of this species. The importance of these findings for understanding the annual life cycle and invasive potential of A. ovalisporum is further discussed herein.


Assuntos
Aphanizomenon/fisiologia , Lagoas/microbiologia , Temperatura , Aphanizomenon/citologia , Aphanizomenon/crescimento & desenvolvimento , Modelos Lineares , Estações do Ano
17.
FEMS Microbiol Ecol ; 99(6)2023 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-37197902

RESUMO

The Arctic soil communities play a vital role in stabilizing and decomposing soil carbon, which affects the global carbon cycling. Studying the food web structure is critical for understanding biotic interactions and the functioning of these ecosystems. Here, we studied the trophic relationships of (microscopic) soil biota of two different Arctic spots in Ny-Ålesund, Svalbard, within a natural soil moisture gradient by combining DNA analysis with stable isotopes as trophic tracers. The results of our study suggested that the soil moisture strongly influenced the diversity of soil biota, with the wetter soil, having a higher organic matter content, hosting a more diverse community. Based on a Bayesian mixing model, the community of wet soil formed a more complex food web, in which bacterivorous and detritivorous pathways were important in supplying carbon and energy to the upper trophic levels. In contrast, the drier soil showed a less diverse community, lower trophic complexity, with the green food web (via unicellular green algae and gatherer organisms) playing a more important role in channelling energy to higher trophic levels. These findings are important to better understand the soil communities inhabiting the Arctic, and for predicting how the ecosystem will respond to the forthcoming changes in precipitation regimes.


Assuntos
Ecossistema , Solo , Solo/química , Teorema de Bayes , Tundra , Regiões Árticas , Carbono/metabolismo , Microbiologia do Solo
18.
Environ Sci Pollut Res Int ; 30(8): 21598-21607, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36271068

RESUMO

Cylindrospermopsin (CYN) is a potent cyanobacterial toxin found in freshwaters worldwide. In this work, the feasibility of the photo-Fenton process under neutral pH using light emitting diodes as irradiation source for the removal of this hazardous cyanotoxin from freshwater was investigated. The impact of the kind of iron chelating agent (ethylenediamine-N, N'-disuccinic acid vs. ethylenedinitrilotetraacetic acid) as well as the effect of the main operating conditions viz. H2O2 dose, Fe(III) load, initial CYN concentration, and Fe(III):EDDS molar ratio on the performance of the process was systematically evaluated. EDDS was selected as the most appropriate iron chelating agent considering the kinetics of the process and the environmental impact (Vibrio fischeri and Artemia salina). Under optimized conditions ([H2O2] = 30 mg L-1; [Fe(III)] = 5 mg L-1; Fe(III):ligand = 1:0.5 (molar ratio)), complete removal of CYN was achieved in 15-min reaction time. Furthermore, the catalytic system showed to be effective in real water matrices (river and reservoir waters) spiked with CYN. Although the presence of inorganic ions (mainly HCO3-/CO32-) and dissolved organic carbon decreased the oxidation rate of CYN due to scavenging reactions and iron coordination, respectively, complete elimination of the cyanotoxin was achieved in all cases. The fate of EDDS along the process was also evaluated to demonstrate that the catalytic system investigated, apart from its effectiveness, warrants the complete absence of residues after reaction. Therefore, the proposed system constitutes a promising method for cyanotoxin treatment either as a drinking water treatment step in conventional plants or as a potential remediation strategy in the natural environment.


Assuntos
Peróxido de Hidrogênio , Poluentes Químicos da Água , Peróxido de Hidrogênio/química , Compostos Férricos , Ferro/química , Toxinas de Cianobactérias , Quelantes de Ferro , Oxirredução , Concentração de Íons de Hidrogênio
19.
Mol Ecol Resour ; 23(5): 1034-1049, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36799013

RESUMO

Environmental DNA-based diversity studies have increased in popularity with the development of high throughput sequencing technologies. This permits the potential simultaneous retrieval of vast amounts of molecular data from many different organisms and species, thus contributing to a wide range of biological disciplines. Environmental DNA protocols designed for protists often focused on the highly conserved small subunit of the ribosome gene, that does not permit species-level assignments. On the other hand, eDNA protocols aiming at species-level assignments allow a fine level ecological resolution and reproducible results. These protocols are currently applied to organisms living in marine and shallow lotic freshwater ecosystems, often in a bioindication purpose. Therefore, in this study, we present a species-level eDNA protocol designed to explore diversity of Arcellinida (Amoebozoa: Tubulinea) testate amoebae taxa that is based on mitochondrial cytochrome oxidase subunit I (COI). These organisms are widespread in lentic water bodies and soil ecosystems. We applied this protocol to 42 samples from peatlands, estuaries and soil environments, recovering all the infraorders in Glutinoconcha (with COI data), except for Hyalospheniformes. Our results revealed an unsuspected diversity in morphologically homogeneous groups such as Cylindrothecina, Excentrostoma or Sphaerothecina. With this protocol we expect to revolutionize the design of modern distributional Arcellinida surveys. Our approach involves a rapid and cost-effective analysis of testate amoeba diversity living in contrasted ecosystems. Therefore, the order Arcellinida has the potential to be established as a model group for a wide range of theoretical and applied studies.


Assuntos
Amebozoários , DNA Ambiental , Lobosea , Ecossistema , Filogenia , Amebozoários/genética , Lobosea/genética , Solo
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