Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 53
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Curr Biol ; 34(9): 2020-2029.e6, 2024 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-38614080

RESUMO

Low genomic diversity is generally indicative of small population size and is considered detrimental by decreasing long-term adaptability.1,2,3,4,5,6 Moreover, small population size may promote gene flow with congeners and outbreeding depression.7,8,9,10,11,12,13 Here, we examine the connection between habitat availability, effective population size (Ne), and extinction by generating a 40× nuclear genome from the extinct blue antelope (Hippotragus leucophaeus). Historically endemic to the relatively small Cape Floristic Region in southernmost Africa,14,15 populations were thought to have expanded and contracted across glacial-interglacial cycles, tracking suitable habitat.16,17,18 However, we found long-term low Ne, unaffected by glacial cycles, suggesting persistence with low genomic diversity for many millennia prior to extinction in ∼AD 1800. A lack of inbreeding, alongside high levels of genetic purging, suggests adaptation to this long-term low Ne and that human impacts during the colonial era (e.g., hunting and landscape transformation), rather than longer-term ecological processes, were central to its extinction. Phylogenomic analyses uncovered gene flow between roan (H. equinus) and blue antelope, as well as between roan and sable antelope (H. niger), approximately at the time of divergence of blue and sable antelope (∼1.9 Ma). Finally, we identified the LYST and ASIP genes as candidates for the eponymous bluish pelt color of the blue antelope. Our results revise numerous aspects of our understanding of the interplay between genomic diversity and evolutionary history and provide the resources for uncovering the genetic basis of this extinct species' unique traits.


Assuntos
Antílopes , Extinção Biológica , Densidade Demográfica , Animais , Antílopes/genética , Antílopes/fisiologia , Variação Genética , Fluxo Gênico , Adaptação Fisiológica/genética , Ecossistema , Genoma
2.
Viruses ; 16(1)2024 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-38257802

RESUMO

The importance of COVID-19 surveillance from wastewater continues to grow since case-based surveillance in the general population has been scaled back world-wide. In Berlin, Germany, quantitative and genomic wastewater monitoring for SARS-CoV-2 is performed in three wastewater treatment plants (WWTP) covering 84% of the population since December 2021. The SARS-CoV-2 Omicron sublineage JN.1 (B.2.86.1.1), was first identified from wastewater on 22 October 2023 and rapidly became the dominant sublineage. This change was accompanied by a parallel and still ongoing increase in the notification-based 7-day-hospitalization incidence of COVID-19 and COVID-19 ICU utilization, indicating increasing COVID-19 activity in the (hospital-prone) population and a higher strain on the healthcare system. In retrospect, unique mutations of JN.1 could be identified in wastewater as early as September 2023 but were of unknown relevance at the time. The timely detection of new sublineages in wastewater therefore depends on the availability of new sequences from GISAID and updates to Pango lineage definitions and Nextclade. We show that genomic wastewater surveillance provides timely public health evidence on a regional level, complementing the existing indicators.


Assuntos
COVID-19 , Águas Residuárias , Humanos , Berlim/epidemiologia , RNA Viral/genética , SARS-CoV-2/genética , COVID-19/epidemiologia , Vigilância Epidemiológica Baseada em Águas Residuárias , Alemanha/epidemiologia
3.
Phys Rev Lett ; 130(17): 176901, 2023 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-37172240

RESUMO

Magnetic 2D materials hold promise to change the miniaturization paradigm of unidirectional photonic components. However, the integration of these materials in devices hinges on the accurate determination of the optical properties down to the monolayer limit, which is still missing. By using hyperspectral wide-field imaging at room temperature, we reveal a nonmonotonic thickness dependence of the complex optical dielectric function in the archetypal magnetic 2D material CrI_{3} extending across different length scales: onsetting at the mesoscale, peaking at the nanoscale, and decreasing again down to the single layer. These results portray a modification of the electronic properties of the material and align with the layer-dependent magnetism in CrI_{3}, shedding light on the long-standing structural conundrum in this material. The unique modulation of the complex dielectric function from the monolayer up to more than 100 layers will be instrumental for understanding mesoscopic effects in layered materials and tuning light-matter interactions in magnetic 2D materials.

4.
J Chem Phys ; 158(6): 064701, 2023 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-36792514

RESUMO

Ion permeation across nanoscopic structures differs considerably from microfluidics because of strong steric constraints, transformed solvent properties, and charge-regulation effects revealed mostly in diluted solutions. However, little is known about nanofluidics in moderately concentrated solutions, which are critically important for industrial applications and living systems. Here, we show that nanoconfinement triggers general biphasic concentration patterns in a myriad of ion transport properties by using two contrasting systems: a biological ion channel and a much larger synthetic nanopore. Our findings show a low-concentration regime ruled by classical Debye screening and another one where ion-ion correlations and enhanced ion-surface interactions contribute differently to each electrophysiological property. Thus, different quantities (e.g., conductance vs noise) measured under the same conditions may appear contradictory because they belong to different concentration regimes. In addition, non-linear effects that are barely visible in bulk conductivity only in extremely concentrated solutions become apparent in nanochannels around physiological conditions.

5.
Analyst ; 148(5): 1050-1057, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36723348

RESUMO

Miniaturized magnetic-based pipette tip microextraction is presented as a sample preparation approach for microsamples. It involves quick dispersion of a diminutive amount of a magnetic sorbent material in a low-volume sample (10 µL) to entrap the target analytes. Next, the dispersion is aspirated using a (semi)automatic pipette through a pipette tip with a small cubic neodymium magnet inside, which retrieves the magnetic sorbent containing the analytes. After discarding the rest of the sample, the sorbent is properly rinsed by aspirating/dispensing deionized water, and then, the analytes are eluted by aspirating/dispensing an appropriate solvent. This approach was employed for the determination of free cortisol in serum and urine from very low birth weight preterm newborns, a vulnerable patient group who present low availability for sampling biological fluids. A magnetic immunosorbent made of a cortisol antibody was employed for the selective extraction, followed by liquid chromatography-tandem mass spectrometry. Good analytical features were obtained, such as limits of detection and quantification of 0.08 and 0.27 ng mL-1, respectively, linearity up to 50 ng mL-1 (R2 > 0.999), RSD values under 15% and relative recoveries between 91 and 111%. The cross-reactivity with other glucocorticoids (i.e., cortisone and prednisolone) was evaluated to show the selectivity of the extraction. Finally, the method applicability was demonstrated towards the determination of free cortisol in the serum and urine samples from low birth weight preterm newborns.


Assuntos
Hidrocortisona , Extração em Fase Sólida , Recém-Nascido , Humanos , Extração em Fase Sólida/métodos , Cromatografia Líquida , Recém-Nascido de muito Baixo Peso , Fenômenos Magnéticos , Limite de Detecção
6.
Sci Total Environ ; 853: 158931, 2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36228784

RESUMO

The use of RNA sequencing from wastewater samples is a valuable way for estimating infection dynamics and circulating lineages of SARS-CoV-2. This approach is independent from testing individuals and can therefore become the key tool to monitor this and potentially other viruses. However, it is equally important to develop easily accessible and scalable tools which can highlight critical changes in infection rates and dynamics over time across different locations given sequencing data from wastewater. Here, we provide an analysis of lineage dynamics in Berlin and New York City using wastewater sequencing and present PiGx SARS-CoV-2, a highly reproducible computational analysis pipeline with comprehensive reports. This end-to-end pipeline includes all steps from raw data to shareable reports, additional taxonomic analysis, deconvolution and geospatial time series analyses. Using simulated datasets (in silico generated and spiked-in samples) we could demonstrate the accuracy of our pipeline calculating proportions of Variants of Concern (VOC) from environmental as well as pre-mixed samples (spiked-in). By applying our pipeline on a dataset of wastewater samples from Berlin between February 2021 and January 2022, we could reconstruct the emergence of B.1.1.7(alpha) in February/March 2021 and the replacement dynamics from B.1.617.2 (delta) to BA.1 and BA.2 (omicron) during the winter of 2021/2022. Using data from very-short-reads generated in an industrial scale setting, we could see even higher accuracy in our deconvolution. Lastly, using a targeted sequencing dataset from New York City (receptor-binding-domain (RBD) only), we could reproduce the results recovering the proportions of the so-called cryptic lineages shown in the original study. Overall our study provides an in-depth analysis reconstructing virus lineage dynamics from wastewater. While applying our tool on a wide range of different datasets (from different types of wastewater sample locations and sequenced with different methods), we show that PiGx SARS-CoV-2 can be used to identify new mutations and detect any emerging new lineages in a highly automated and scalable way. Our approach can support efforts to establish continuous monitoring and early-warning projects for detecting SARS-CoV-2 or any other pathogen.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/epidemiologia , Águas Residuárias , Cidade de Nova Iorque , Manosiltransferases
7.
Heredity (Edinb) ; 129(5): 305-315, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36229647

RESUMO

Hybridization and introgression have played important roles in the history of various species, including lineage diversification and the evolution of adaptive traits. Hybridization can accelerate the development of reproductive isolation between diverging species, and thus valuable insight into the evolution of reproductive barrier formation may be gained by studying secondary contact zones. Hedgehogs of the genus Erinaceus, which are insectivores sensitive to changes in climate, are a pioneer model in Pleistocene phylogeography. The present study provides the first genome-wide SNP data regarding the Erinaceus hedgehogs species complex, offering a unique comparison of two secondary contact zones between Erinaceus europaeus and E. roumanicus. Results confirmed diversification of the genus during the Pleistocene period, and detected a new refugial lineage of E. roumanicus outside the Mediterranean basin, most likely in the Ponto-Caspian region. In the Central European zone, the level of hybridization was low, whereas in the Russian-Baltic zone, both species hybridise extensively. Asymmetrical gene flow from E. europaeus to E. roumanicus suggests that reproductive isolation varies according to the direction of the crosses in the hybrid zones. However, no loci with significantly different patterns of introgression were detected. Markedly different pre- and post-zygotic barriers, and thus diverse modes of species boundary maintenance in the two contact zones, likely exist. This pattern is probably a consequence of the different age and thus of the different stage of evolution of reproductive isolating mechanisms in each hybrid zone.


Assuntos
Ouriços , Hibridização Genética , Animais , Ouriços/genética , Isolamento Reprodutivo , Fluxo Gênico , Filogeografia
8.
Anal Chim Acta ; 1221: 340117, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35934400

RESUMO

In this work, a lab-made and affordable high-throughput pipette tip microextraction strategy is presented. In this approach, a magnetic sorbent is quickly dispersed in the sample by means of a disperser solvent and the resulting dispersion is immediately aspirated into a pipette tip containing a small neodymium magnet inside, which entraps the magnetic sorbent containing the analytes. The sample is then discarded, and the subsequent cleaning and desorption steps are conducted by aspirating/dispensing the suitable solvents. This methodology provides satisfactory results when compared with previous pipette tip extraction strategies (i.e., pipette-tip solid-phase extraction and dispersive pipette extraction). Furthermore, it requires a minimum number of aspirating/dispensing cycles, thus benefiting the ergonomics for the operator, and it is not commercially dependent. This new approach has been tested by measuring testosterone levels in saliva of volunteers as a proof-of-concept. In this regard, a magnetic composite made of CoFe2O4 magnetic nanoparticles embedded in octadecyl bonded silica microparticles was employed as sorbent material. Testosterone was quantified by liquid chromatography coupled to tandem mass spectrometry. Under the optimized conditions, low limits of detection and quantification (7.5 ng L-1 and 24.8 ng L-1, respectively), good repeatability (RSD <9%) and relative recoveries between 82 and 106% were obtained with just one adsorption and two desorption cycles, which requires few seconds per sample. In order to increase even more the sample throughput, a multichannel pipette was also evaluated.


Assuntos
Microextração em Fase Líquida , Testosterona , Humanos , Limite de Detecção , Fenômenos Magnéticos , Saliva , Extração em Fase Sólida/métodos , Solventes/química , Espectrometria de Massas em Tandem , Congêneres da Testosterona
9.
Nutrients ; 14(14)2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35889831

RESUMO

The core microbiome, which refers to a set of consistent microbial features across populations, is of major interest in microbiome research and has been addressed by numerous studies. Understanding the core microbiome can help identify elements that lead to dysbiosis, and lead to treatments for microbiome-related health states. However, defining the core microbiome is a complex task at several levels. In this review, we consider the current state of core human microbiome research. We consider the knowledge that has been gained, the factors limiting our ability to achieve a reliable description of the core human microbiome, and the fields most likely to improve that ability. DNA sequencing technologies and the methods for analyzing metagenomics and amplicon data will most likely facilitate higher accuracy and resolution in describing the microbiome. However, more effort should be invested in characterizing the microbiome's interactions with its human host, including the immune system and nutrition. Other components of this holobiontic system should also be emphasized, such as fungi, protists, lower eukaryotes, viruses, and phages. Most importantly, a collaborative effort of experts in microbiology, nutrition, immunology, medicine, systems biology, bioinformatics, and machine learning is probably required to identify the traits of the core human microbiome.


Assuntos
Microbioma Gastrointestinal , Microbiota , Disbiose , Humanos , Metagenômica/métodos , Análise de Sequência de DNA
10.
Talanta ; 243: 123378, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35303553

RESUMO

In this work, a low toxicity deep eutectic solvent-based ferrofluid is presented for the first time as magnetic fluid to be used as an efficient solvent in liquid-based microextraction techniques. This ferrofluid is made of a hydrophobic deep eutectic solvent, composed by menthol and thymol in a 1:5 molar ratio as carrier solvent, and oleic acid-coated cobalt ferrite (CoFe2O4@oleic acid) magnetic nanoparticles. This material was characterized via magnetism measurement, scanning electron microscopy, infrared spectroscopy and density measurement. The determination of UV filters in environmental water samples was selected as model analytical application to test the extraction performance of this new ferrofluid by employing stir bar dispersive liquid microextraction, prior to liquid chromatography-tandem mass spectrometry analysis. The response surface methodology was used as a multivariate optimization method for extraction step. Under the optimized conditions, good analytical features were obtained, such as low limits of detection between 7 and 83 ng L-1, good repeatability (relative standard deviations, RSD (%) below 15%), enrichment factors between 46 and 101 and relative recoveries between 80 and 117%, proving the good extraction capability of this ferrofluid. Finally, the method was successfully applied to three environmental waters (beach and river waters), finding trace amounts of the target UV filters. The presented low toxicity deep eutectic solvent-based ferrofluid results to be a good alternative to conventional solvents used in liquid-phase microextraction techniques.


Assuntos
Solventes Eutéticos Profundos , Microextração em Fase Líquida , Coloides , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Microextração em Fase Líquida/métodos , Solventes/química
11.
Mol Ecol ; 31(10): 2898-2919, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35334142

RESUMO

Species of the mustelid subfamily Guloninae inhabit diverse habitats on multiple continents, and occupy a variety of ecological niches. They differ in feeding ecologies, reproductive strategies and morphological adaptations. To identify candidate loci associated with adaptations to their respective environments, we generated a de novo assembly of the tayra (Eira barbara), the earliest diverging species in the subfamily, and compared this with the genomes available for the wolverine (Gulo gulo) and the sable (Martes zibellina). Our comparative genomic analyses included searching for signs of positive selection, examining changes in gene family sizes and searching for species-specific structural variants. Among candidate loci associated with phenotypic traits, we observed many related to diet, body condition and reproduction. For example, for the tayra, which has an atypical gulonine reproductive strategy of aseasonal breeding, we observed species-specific changes in many pregnancy-related genes. For the wolverine, a circumpolar hypercarnivore that must cope with seasonal food scarcity, we observed many changes in genes associated with diet and body condition. All types of genomic variation examined (single nucleotide polymorphisms, gene family expansions, structural variants) contributed substantially to the identification of candidate loci. This argues strongly for consideration of variation other than single nucleotide polymorphisms in comparative genomics studies aiming to identify loci of adaptive significance.


Assuntos
Mustelidae , Adaptação Fisiológica/genética , Animais , Genoma , Genômica , Mustelidae/genética , Fenótipo
12.
J Sep Sci ; 45(1): 210-222, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34490730

RESUMO

Dispersive liquid-liquid microextraction is one of the most widely used microextraction techniques currently in the analytical chemistry field, mainly due to its simplicity and rapidity. The operational mode of this approach has been constantly changing since its introduction, adapting to new trends and applications. Most of these changes are related to the nature of the solvent employed for the microextraction. From the classical halogenated solvents (e.g., chloroform or dichloromethane), different alternatives have been proposed in order to obtain safer and non-pollutants microextraction applications. In this sense, low-density solvents, such as alkanols, switchable hydrophobicity solvents, and ionic liquids were the first and most popular replacements for halogenated solvents, which provided similar or better results than these classical dispersive liquid-liquid microextraction solvents. However, despite the good performances obtained with low-density solvents and ionic liquids, researchers have continued investigating in order to obtain even greener solvents for dispersive liquid-liquid microextraction. For that reason, in this review, the evolution over the last five years of the three types of solvents already mentioned and two of the most promising solvent alternatives (i.e., deep eutectic solvents and supramolecular solvents), have been studied in detail with the purpose of discussing which one provides the greenest alternative.

13.
ACS Appl Mater Interfaces ; 13(45): 54447-54455, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34735108

RESUMO

We describe experimentally and theoretically the fluoride-induced negative differential resistance (NDR) phenomena observed in conical nanopores operating in aqueous electrolyte solutions. The threshold voltage switching occurs around 1 V and leads to sharp current drops in the nA range with a peak-to-valley ratio close to 10. The experimental characterization of the NDR effect with single pore and multipore samples concern different pore radii, charge concentrations, scan rates, salt concentrations, solvents, and cations. The experimental fact that the effective radius of the pore tip zone is of the same order of magnitude as the Debye length for the low salt concentrations used here is suggestive of a mixed pore surface and bulk conduction regime. Thus, we propose a two-region conductance model where the mobile cations in the vicinity of the negative pore charges are responsible for the surface conductance, while the bulk solution conductance is assumed for the pore center region.

14.
Mol Biol Evol ; 38(9): 3884-3897, 2021 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-34426844

RESUMO

During the Miocene, Hyaenidae was a highly diverse family of Carnivora that has since been severely reduced to four species: the bone-cracking spotted, striped, and brown hyenas, and the specialized insectivorous aardwolf. Previous studies investigated the evolutionary histories of the spotted and brown hyenas, but little is known about the remaining two species. Moreover, the genomic underpinnings of scavenging and insectivory, defining traits of the extant species, remain elusive. Here, we generated an aardwolf genome and analyzed it together with the remaining three species to reveal their evolutionary relationships, genomic underpinnings of their scavenging and insectivorous lifestyles, and their respective genetic diversities and demographic histories. High levels of phylogenetic discordance suggest gene flow between the aardwolf lineage and the ancestral brown/striped hyena lineage. Genes related to immunity and digestion in the bone-cracking hyenas and craniofacial development in the aardwolf showed the strongest signals of selection, suggesting putative key adaptations to carrion and termite feeding, respectively. A family-wide expansion in olfactory receptor genes suggests that an acute sense of smell was a key early adaptation. Finally, we report very low levels of genetic diversity within the brown and striped hyenas despite no signs of inbreeding, putatively linked to their similarly slow decline in effective population size over the last ∼2 million years. High levels of genetic diversity and more stable population sizes through time are seen in the spotted hyena and aardwolf. Taken together, our findings highlight how ecological specialization can impact the evolutionary history, demographics, and adaptive genetic changes of an evolutionary lineage.


Assuntos
Adaptação Biológica , Evolução Biológica , Fluxo Gênico , Variação Genética , Hyaenidae/genética , Animais , Comportamento Alimentar , Genoma , Masculino , Densidade Demográfica
15.
Genes (Basel) ; 12(8)2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34440410

RESUMO

Since the 19th century, the addax (Addax nasomaculatus) has lost approximately 99% of its former range. Along with its close relatives, the blue antelope (Hippotragus leucophaeus) and the scimitar-horned oryx (Oryx dammah), the addax may be the third large African mammal species to go extinct in the wild in recent times. Despite this, the evolutionary history of this critically endangered species remains virtually unknown. To gain insight into the population history of the addax, we used hybridization capture to generate ten complete mitochondrial genomes from historical samples and assembled a nuclear genome. We found that both mitochondrial and nuclear diversity are low compared to other African bovids. Analysis of mitochondrial genomes revealed a most recent common ancestor ~32 kya (95% CI 11-58 kya) and weak phylogeographic structure, indicating that the addax likely existed as a highly mobile, panmictic population across its Sahelo-Saharan range in the past. PSMC analysis revealed a continuous decline in effective population size since ~2 Ma, with short intermediate increases at ~500 and ~44 kya. Our results suggest that the addax went through a major bottleneck in the Late Pleistocene, remaining at low population size prior to the human disturbances of the last few centuries.


Assuntos
Antílopes/classificação , Espécies em Perigo de Extinção , Extinção Biológica , Animais , Antílopes/genética , Biodiversidade , Genoma Mitocondrial , Hibridização Genética , Filogeografia
16.
J Chromatogr A ; 1652: 462361, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34261023

RESUMO

A modification of magnetic-based solvent-assisted dispersive solid-phase extraction (M-SA-DSPE) has been employed for the determination of the biomarkers cortisol and cortisone in saliva samples. M-SA-DSPE is based on the dispersion of the sorbent material by using a disperser solvent like in dispersive solid phase extraction (SA-DSPE) but a magnetic sorbent is used like in magnetic dispersive solid-phase extraction (M-DSPE). Thus, the magnetic sorbent containing the target analytes is retrieved using an external magnet like in M-DSPE. Finally, the analytes are desorbed into a small volume of organic solvent for the subsequent chromatographic analysis. To this regard, a M-SA-DSPE-based method was developed using a magnetic composite as sorbent, made of CoFe2O4 magnetic nanoparticles embedded into a reversed phase polymer (Strata-XTM-RP), which exhibits affinity to the target analytes. Then, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to measure both analytes in the M-SA-DSPE extract. Under the optimized conditions, good analytical features were obtained: limits of detection of 0.029 ng mL-1 for cortisol and 0.018 ng mL-1 for cortisone, repeatability (as RSD) ≤ 10 %, and relative recoveries between 86 and 111 %, showing no significant matrix effects. Finally, the proposed method was applied to the analysis of saliva from different volunteers. This new methodology allows a fast and non-invasive determination of cortisol and cortisone, and it employs small amounts of sample, organic solvent and sorbent. Likewise, the sample treatment is minimum, since any supporting equipment (vortex, centrifuge, ultrasounds, etc.) is required.


Assuntos
Cortisona , Hidrocortisona , Saliva , Extração em Fase Sólida , Cromatografia Líquida , Cortisona/análise , Humanos , Hidrocortisona/análise , Fenômenos Magnéticos , Saliva/química , Extração em Fase Sólida/métodos , Solventes/química , Espectrometria de Massas em Tandem
17.
Talanta ; 231: 122375, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33965039

RESUMO

Magnetic-based microextraction approaches have gained popularity in recent years due to the magnetic properties of the extraction phases allowing to handle them easier and more efficiently. This work describes a magnetic-based analytical method for the determination of the family of nitro musks in environmental water samples. These compounds have been of great concern due to their environmental impacts and potential health effects. The method is based on stir bar sorptive-dispersive microextraction (SBSDME) as extraction approach, prior to thermal desorption coupled to gas chromatography-mass spectrometry analysis (TD-GC-MS). For this purpose, polydopamine-coated cobalt ferrite magnetic nanoparticles (CoFe2O4@PDA) were used as extraction material. The main parameters involved in the extraction procedure (i.e., sorbent amount, extraction time and ionic strength) as well as in the thermal desorption step (i.e., temperature and desorption time) were evaluated in order to obtain the highest sensitivity. Under the selected conditions, the method showed good linearity, limits of detection and quantification in the low ng L-1 range, intra- and inter-day repeatability with RSD <15%, and high enrichment factors (178-640). Finally, the method was applied to four environmental water samples of different origin. Relative recovery values ranging from 91 to 120% highlighted that the matrices under consideration do not affect the extraction process. This work constitutes the first time in which nitro musks compounds were selectively extracted by taking advantage the high potential that magnetic-based microextraction techniques offer, specially SBSDME.

18.
Anal Chim Acta ; 1153: 338271, 2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33714438

RESUMO

Current trends in sample preparation focus on the miniaturization of the process resulting in what is known as microextraction techniques. Among them stir bar sorptive dispersive microextraction (SBSDME) is one of the most recent techniques. It was presented a few years ago as a hybrid microextraction technique that combines the principles of stir bar sorptive extraction (SBSE) and dispersive solid phase extraction (DSPE). This novel technique introduces, into the sample solution, a bar-shaped magnet coated with a magnetic (nano)material, which is maintained on the surface by magnetism. Once stirring starts, the competitive action between magnetism and rotational force is exploited. At low rotational speed the (nano)material is retained on the magnet reminding SBSE, whereas at high sufficiently rotational speed the rotational force surpasses magnetism so that the magnetic (nano)material is dispersed into the sample solution as in DSPE. Upon halting rotation, the magnetic field prevails again and attracts the magnetic (nano)material containing the analytes back on the surface of the stirring bar. Finally, the extracted analytes are chemically or thermally desorbed before their measurement with the appropriate analytical instrument. When compared separately to SBSE and DSPE procedures, SBSDME affords, in a single approach, advantages such as lower extraction times than SBSE and easier extraction and post-extraction treatment than DSPE. The main purpose of this tutorial review is to describe the fundamentals and the experimental variables involved in this technique, as well as to compile and critically discuss the published papers concerning analytical methods based on the use of the SBSDME approach, analyzing its evolution and future prospects.

19.
Sci Rep ; 11(1): 1633, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452404

RESUMO

Hybridogenesis is a reproductive tool for sexual parasitism. Hybridogenetic hybrids use gametes from their sexual host for their own reproduction, but sexual species gain no benefit from such matings as their genome is later eliminated. Here, we examine the presence of sexual parasitism in water frogs through crossing experiments and genome-wide data. We specifically focus on the famous Central-European populations where Pelophylax esculentus males (hybrids of P. ridibundus and P. lessonae) live with P. ridibundus. We identified a system where the hybrids commonly produce two types of clonal gametes (hybrid amphispermy). The haploid lessonae genome is clonally inherited from generation to generation and assures the maintenance of hybrids through a process, in which lessonae sperm fertilize P. ridibundus eggs. The haploid ridibundus genome in hybrids received from P. ridibundus a generation ago, is perpetuated as clonal ridibundus sperm and used to fertilize P. ridibundus eggs, yielding female P. ridibundus progeny. These results imply animal reproduction in which hybridogenetic taxa are not only sexual parasites, but also participate in the formation of a sexual taxon in a remarkable way. This occurs through a process by which sexual gametes are being captured, converted to clones, and returned to sexual populations in one generation.


Assuntos
Genoma , Rana esculenta/genética , Animais , Feminino , Loci Gênicos , Haploidia , Masculino , Repetições de Microssatélites/genética , Análise de Componente Principal , Rana ridibunda/genética
20.
Mitochondrial DNA B Resour ; 5(3): 3456-3457, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33367016

RESUMO

Here, we present the first complete mitochondrial genome of the pentastomid Linguatula arctica collected from the nasal passages of a reindeer (Rangifer tarandus) in Norway. The full length mitochondrial genome of L. arctica, which measures 14,789 bp in length, contains 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. A clear A + T bias is observed in the mitogenome of L. arctica with an overall base composition of 32.6% A, 27.5% T, 32.8% C, and 7,1% G., and a GC content of 39.9%. The gene arrangement is identical to that of previously described pentastomid mitogenomes.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...