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1.
Sensors (Basel) ; 20(17)2020 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-32842601

RESUMO

The global burden of coronavirus disease 2019 (COVID-19) to public health and global economy has stressed the need for rapid and simple diagnostic methods. From this perspective, plasmonic-based biosensing can manage the threat of infectious diseases by providing timely virus monitoring. In recent years, many plasmonics' platforms have embraced the challenge of offering on-site strategies to complement traditional diagnostic methods relying on the polymerase chain reaction (PCR) and enzyme-linked immunosorbent assays (ELISA). This review compiled recent progress on the development of novel plasmonic sensing schemes for the effective control of virus-related diseases. A special focus was set on the utilization of plasmonic nanostructures in combination with other detection formats involving colorimetric, fluorescence, luminescence, or Raman scattering enhancement. The quantification of different viruses (e.g., hepatitis virus, influenza virus, norovirus, dengue virus, Ebola virus, Zika virus) with particular attention to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was reviewed from the perspective of the biomarker and the biological receptor immobilized on the sensor chip. Technological limitations including selectivity, stability, and monitoring in biological matrices were also reviewed for different plasmonic-sensing approaches.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Ressonância de Plasmônio de Superfície/métodos , Betacoronavirus/patogenicidade , Colorimetria , Infecções por Coronavirus/virologia , Fluorescência , Humanos , Nanoestruturas/química , Pandemias , Pneumonia Viral/virologia , Análise Espectral Raman
2.
Int J Nanomedicine ; 15: 4933-4941, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764926

RESUMO

Purpose: The aim of this study was to develop an avidin-modified macromolecular lipid magnetic sphere and its application in differential diagnosis of liver disease and liver cancer. Materials and Methods: Lectin-modified macromolecular lipid magnetic spheres were prepared by thin-film hydration method using lentil lectin derivatives (LCA-HQ) and cholesterol as raw materials. Alpha-fetoprotein variants (AFP-L3) in serum from healthy people, liver disease and liver cancer patients were isolated using the prepared lectin-modified macromolecular lipid magnetic spheres, and alpha-fetoprotein (AFP) and AFP-L3 were detected by fully automatic time-resolved fluorescence immunoassay. Results: The lectin polymer lipid magnetic sphere prepared in this study was superparamagnetic and encapsulated by a lectin derivative. There was no significant difference in the recovery rate of AFP-L3 between avidin magnetic ball-automatic time-resolved fluorescence immunoassay and manual micro-affinity column method (p>0.05). We found that AFP-L3 can be used as a differential indicator between liver cancer and liver disease. The positive rate of AFP and AFP-L3 in liver cancer patients was higher than that in healthy people and liver disease patients (p<0.001). The AUC (95% CI) of AFP and AFP-L3 were 0.743 ± 0.031 and 0.850 ± 0.024, respectively. AFP-L3 AUC value is greater than AFP; therefore, AFP-L3 distinguishes liver cancer more accurately, and the difference is statistically different, p<0.05. Conclusion: We proposed a novel method for integration of the lectin polymer lipid magnetic spheres and time-resolved fluorescence immunoassay that enables simple, accurate and rapid determination of AFP-L3 in clinical samples. To be noted, fully automatic time-resolved fluorescence immunoassay compared with the commonly used techniques in clinical practice, the measurement procedure is simple and is expected to be used for the detection and accurate diagnosis of liver cancer.


Assuntos
Fluorescência , Lipossomos/química , Neoplasias Hepáticas/diagnóstico , Mutação , Polímeros/química , alfa-Fetoproteínas/genética , alfa-Fetoproteínas/metabolismo , Adulto , Área Sob a Curva , Automação , Biomarcadores Tumorais/sangue , Feminino , Humanos , Imunoensaio/métodos , Neoplasias Hepáticas/sangue , Imãs/química , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
3.
Nat Commun ; 11(1): 3847, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737299

RESUMO

Reporter systems are routinely used in plant genetic engineering and functional genomics research. Most such plant reporter systems cause accumulation of foreign proteins. Here, we demonstrate a protein-independent reporter system, 3WJ-4 × Bro, based on a fluorescent RNA aptamer. Via transient expression assays in both Escherichia coli and Nicotiana benthamiana, we show that 3WJ-4 × Bro is suitable for transgene identification and as an mRNA reporter for expression pattern analysis. Following stable transformation in Arabidopsis thaliana, 3WJ-4 × Bro co-segregates and co-expresses with target transcripts and is stably inherited through multiple generations. Further, 3WJ-4 × Bro can be used to visualize virus-mediated RNA delivery in plants. This study demonstrates a protein-independent reporter system that can be used for transgene identification and in vivo dynamic analysis of mRNA.


Assuntos
Aptâmeros de Nucleotídeos/genética , Arabidopsis/genética , Brassica/genética , Engenharia Genética/métodos , RNA Mensageiro/genética , Tabaco/genética , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Arabidopsis/metabolismo , Compostos de Benzil/química , Brassica/metabolismo , Fluorescência , Corantes Fluorescentes/química , Regulação da Expressão Gênica , Genes Reporter , Imidazolinas/química , Folhas de Planta/genética , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , RNA Mensageiro/metabolismo , Tabaco/metabolismo , Transformação Genética
4.
Nat Commun ; 11(1): 4032, 2020 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-32788575

RESUMO

Hydrogel-based devices are widely used as flexible electronics, biosensors, soft robots, and intelligent human-machine interfaces. In these applications, high stretchability, low hysteresis, and anti-fatigue fracture are essential but can be rarely met in the same hydrogels simultaneously. Here, we demonstrate a hydrogel design using tandem-repeat proteins as the cross-linkers and random coiled polymers as the percolating network. Such a design allows the polyprotein cross-linkers only to experience considerable forces at the fracture zone and unfold to prevent crack propagation. Thus, we are able to decouple the hysteresis-toughness correlation and create hydrogels of high stretchability (~1100%), low hysteresis (< 5%), and high fracture toughness (~900 J m-2). Moreover, the hydrogels show a high fatigue threshold of ~126 J m-2 and can undergo 5000 load-unload cycles up to 500% strain without noticeable mechanical changes. Our study provides a general route to decouple network elasticity and local mechanical response in synthetic hydrogels.


Assuntos
Reagentes para Ligações Cruzadas/química , Hidrogéis/química , Poliproteínas/química , Estresse Mecânico , Resinas Acrílicas/química , Fluorescência , Fenômenos Mecânicos
5.
Artigo em Chinês | MEDLINE | ID: mdl-32842175

RESUMO

Objective:To determine the cell types composing blood-labyrinth barrier in stira vascularis of cochlear lateral wall, analyze the distribution of these composing cells in blood-labyrinth barrier, and to investigate the relationship between perivascular-resident macrophages (PVMs), endothelial cells and pericytes in blood-labyrinth barrier. Method:Cochlear lateral wall tissues were harvested from adult GFP-transgenic mice(C57BL/6). Then the isolated whole stria vascularis tissue was scanned at 0.5 um intervals on the Z axis by two-photon confocal microscope and a 3D-structure of stria vascularis was reconstructed to observe the distribution of capillaries in blood-labyrinth barrier. Cochlear stria vascularis isolated from Balb/c mice was stained by mulit-immunofluorescence and then 3D real time deconvolution of stria vascularis was performed by Imaris software to investigate the distribution of PVMs and pericytes, and their contacting with basement membrane of capillaries was also observed. The ultrastructure of endothelial cells, pericytes and PVMs in blood-labyrinth barrier was observed using transmission electron microscope. Result:The vessels in stria vascularis are parallel to modiolus, distinct from that in spiral ligament which are perpendicular to modiolus. Numerous pericyts in stria vascularis are ensheathed by a vascular basement membrane shared with endothelial cells and closely attaching to the lateral wall of endothelial cells, while PVMs are located outside basement membrane of capillaries. Unlike pericytes that surround one capillary, PVMs branch to connect with more than one capillary. Conclusion:Serial layers on the Z axis scanned by two-photon confocal microscope and a 3D-structure reconstructed by Imaris 3D deconvolution helps to display the micro structure of capillaries in cochlear lateral wall clearly, which could be applied to analyze the 3D structure and function of blood-labyrinth barrier. PVMs in stria vascularis contact with more than one vessel through cytoplasmic processes, suggesting that PVMs may play a more significant role than pericytes in the integrity of blood-labyrinth barrier.


Assuntos
Orelha Interna , Pericitos , Animais , Cóclea , Células Endoteliais , Fluorescência , Camundongos , Camundongos Endogâmicos C57BL , Estria Vascular
6.
Nat Commun ; 11(1): 4316, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859932

RESUMO

Plants utilize a UV-B (280 to 315 nm) photoreceptor UVR8 (UV RESISTANCE LOCUS 8) to sense environmental UV levels and regulate gene expression to avoid harmful UV effects. Uniquely, UVR8 uses intrinsic tryptophan for UV-B perception with a homodimer structure containing 26 structural tryptophan residues. However, besides 8 tryptophans at the dimer interface to form two critical pyramid perception centers, the other 18 tryptophans' functional role is unknown. Here, using ultrafast fluorescence spectroscopy, computational methods and extensive mutations, we find that all 18 tryptophans form light-harvesting networks and funnel their excitation energy to the pyramid centers to enhance light-perception efficiency. We determine the timescales of all elementary tryptophan-to-tryptophan energy-transfer steps in picoseconds to nanoseconds, in excellent agreement with quantum computational calculations, and finally reveal a significant leap in light-perception quantum efficiency from 35% to 73%. This photoreceptor is the first system discovered so far, to be best of our knowledge, using natural amino-acid tryptophans to form networks for both light harvesting and light perception.


Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/metabolismo , Fotorreceptores de Plantas/química , Fotorreceptores de Plantas/metabolismo , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Proteínas Cromossômicas não Histona/genética , Transferência de Energia , Fluorescência , Cinética , Luz , Modelos Moleculares , Mutação , Conformação Proteica , Multimerização Proteica , Triptofano/metabolismo , Raios Ultravioleta
9.
Int J Esthet Dent ; 15(3): 318-332, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760926

RESUMO

OBJECTIVE: The fluorescence properties of tooth-colored restorative materials can vary according to the shade of the material. The objective of this study was to investigate the fluorescence behavior of different shades of selected contemporary tooth-colored restorative materials when illuminated with violet light (405 nm wavelength). METHODS: Fifteen different tooth-colored restorative materials, in total 111 shades, were analyzed. Samples of 10-mm diameter and 5-mm thickness were fabricated for each shade. The levels of red, blue, green, and luminosity were analyzed for each sample under 405 nm illumination and an orange long pass filter, using data from the histogram tool in Adobe Photoshop software. RESULTS: There were significant variations in fluorescence luminosity according to both shade and manufacturer. Within any one brand of material, fluorescence emissions differed according to shade, with the lightest shades giving the strongest emissions. Variations in fluorescence were most prominent for composite resins, followed by ormocers, and then glass-ionomer materials. There were also significant variations in fluorescence luminosity between materials of the same shade made by different manufacturers. CONCLUSION: Fluorescence emissions vary considerably among different shades of the same material, and between different materials that are labelled as having the same shade. In the present study, the lightest shades had the greatest emissions under UV light.


Assuntos
Resinas Compostas , Restauração Dentária Permanente , Cor , Materiais Dentários , Fluorescência , Teste de Materiais
10.
Chemosphere ; 259: 127396, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32645596

RESUMO

The performance of the UV/H2O2 advanced oxidation process (AOP) is dependent on water quality parameters, including the UV absorbance coefficient at 254 nm and hydroxyl radical (•OH) water background demand (scavenging factor, s-1). The •OH scavenging factor represents the •OH scavenging rate of the background substances in the water matrix, and it is known to be one of the key parameters to predict the performance of the UV/H2O2 process. The •OH scavenging factor has been determined experimentally by using a probe compound such as pCBA and rhodamine B. The experimental method has been validated to accurately predict the micropollutants removal in the UV/H2O2 process, but there is a need for an easier and simple method of determining the OH scavenging factor. We evaluated the alternative method to analyze the •OH scavenging factor using fluorescence excitation-emission matrix and parallel factor analysis (F-EEM/PARAFAC). The correlation between •OH scavenging factor and the spectroscopic characteristics and structure of different organic matter types was evaluated. Organic matter was characterized using a fluorescence excitation-emission matrix, parallel factor analysis, and liquid chromatography-organic carbon detection. Second-order reaction rates of humic acid sodium salt, sodium alginate, Suwannee River humic acid and bovine serum albumin were calculated as 1.30 × 108 M-1 s-1, 1.39 × 108 M-1 s-1, 1.03 × 108 M-1 s-1, and 3.17 × 107 M-1 s-1, respectively. Results of PARAFAC analysis, the ratio of humic and fulvic fluorescence component 2 to terrestrial humic-like fluorescence component 1 (C2/C1), and •OH scavenging factor showed high linearity. A predictive model, which combines with the F-EEM/PARAFAC method, predicted the optimal UV and H2O2 dose to achieve target compound removal.


Assuntos
Poluentes Químicos da Água/química , Purificação da Água/métodos , Análise Fatorial , Fluorescência , Substâncias Húmicas/análise , Peróxido de Hidrogênio/análise , Radical Hidroxila/química , Oxirredução , Rios/química , Espectrometria de Fluorescência/métodos , Água/análise , Poluentes Químicos da Água/análise , Qualidade da Água
11.
ACS Sens ; 5(8): 2331-2337, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32660240

RESUMO

The SARS-CoV-2 infection that caused the COVID-19 pandemic quickly spread worldwide within two months. Rapid diagnosis of the disease and isolation of patients are effective ways to prevent and control the spread of COVID-19. Therefore, a sensitive immunofluorescent assay method was developed for rapid detection of special IgM and IgG of COVID-19 in human serum within 10 min. The recombinant nucleocapsid protein of 2019 novel coronavirus was used as capture antigen. Lanthanide, Eu(III) fluorescent microsphere, was used to qualitatively/semiquantitatively determine the solid phase immunochromatographic assay. A total of 28 clinical positive and 77 negative serum or plasma samples were included in the test. Based on the analysis of serum or plasma from COVID-19 patients and healthy people, the sensitivity and specificity of the immunochromatographic assay were calculated as 98.72% and 100% (IgG), and 98.68% and 93.10% (IgM), respectively. The results demonstrated that rapid immunoassay has high sensitivity and specificity and was useful for rapid serodiagnosis of COVID-19.


Assuntos
Infecções por Coronavirus/diagnóstico , Imunoensaio/métodos , Microesferas , Pneumonia Viral/diagnóstico , Testes Sorológicos/métodos , Európio , Fluorescência , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Elementos da Série dos Lantanídeos , Proteínas do Nucleocapsídeo/imunologia , Pandemias , Sensibilidade e Especificidade , Testes Sorológicos/normas , Fatores de Tempo
12.
BMC Bioinformatics ; 21(1): 332, 2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32709217

RESUMO

BACKGROUND: In cell biology, increasing focus has been directed to fast events at subcellular space with the advent of fluorescent probes. As an example, voltage sensitive dyes (VSD) have been used to measure membrane potentials. Yet, even the most recently developed genetically encoded voltage sensors have demanded exhausting signal averaging through repeated experiments to quantify action potentials (AP). This analysis may be further hampered in subcellular signals defined by small regions of interest (ROI), where signal-to-noise ratio (SNR) may fall substantially. Signal processing techniques like blind source separation (BSS) are designed to separate a multichannel mixture of signals into uncorrelated or independent sources, whose potential to separate ROI signal from noise has been poorly explored. Our aims are to develop a method capable of retrieving subcellular events with minimal a priori information from noisy cell fluorescence images and to provide it as a computational tool to be readily employed by the scientific community. RESULTS: In this paper, we have developed METROID (Morphological Extraction of Transmembrane potential from Regions Of Interest Device), a new computational tool to filter fluorescence signals from multiple ROIs, whose code and graphical interface are freely available. In this tool, we developed a new ROI definition procedure to automatically generate similar-area ROIs that follow cell shape. In addition, simulations and real data analysis were performed to recover AP and electroporation signals contaminated by noise by means of four types of BSS: Principal Component Analysis (PCA), Independent Component Analysis (ICA), and two versions with discrete wavelet transform (DWT). All these strategies allowed for signal extraction at low SNR (- 10 dB) without apparent signal distortion. CONCLUSIONS: We demonstrate the great capability of our method to filter subcellular signals from noisy fluorescence images in a single trial, avoiding repeated experiments. We provide this novel biomedical application with a graphical user interface at https://doi.org/10.6084/m9.figshare.11344046.v1 , and its code and datasets are available in GitHub at https://github.com/zoccoler/metroid .


Assuntos
Razão Sinal-Ruído , Software , Algoritmos , Animais , Automação , Corantes/química , Simulação por Computador , Fluorescência , Humanos , Potenciais da Membrana , Análise de Componente Principal , Ratos , Processamento de Sinais Assistido por Computador , Frações Subcelulares/metabolismo , Interface Usuário-Computador
13.
J Dtsch Dermatol Ges ; 18(7): 682-690, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32657017

RESUMO

BACKGROUND: The melanin fluorescence of skin lesions is measurable with two-photon excitation, a process termed dermatofluoroscopy, which has shown a shift from the green spectra in benign melanocytic lesions to the red spectra in melanoma. This study addressed the question as to which kind of pigmented lesions can be correctly diagnosed as melanin-bearing malignant tumors. METHODS: 476 pigmented lesions including 101 cutaneous melanomas were analyzed with dermatofluoroscopy, measuring the melanin fluorescence in a grid-like fashion with a separation of measurement points of 0.2 mm. The results of the dermatofluoroscopy are presented as a diagnostic score with a cut-off score of ≥ 28 for the diagnosis of melanin-bearing malignant tumors, and were compared to the gold standard of histopathology. RESULTS: A highly significant difference (p < 0.0001) between the diagnostic scores of different skin tumors was found. Dermatofluoroscopy scores showed the highest sensitivity for melanomas (92.1 %). Interestingly, most pigmented basal cell carcinomas (BCCs, 88.9 %) were diagnosed as melanin-bearing malignant tumors. A higher sensitivity for the correct diagnosis was observed in older patients (≥ 53 years, p = 0.003), in patients with skin tanning (p = 0.025), and in patients with freckles during childhood (p = 0.046). CONCLUSIONS: Two-photon fluorescence is an innovative technique for the diagnosis of pigmented skin lesions, and shows a high sensitivity for detection of melanomas and pigmented BCCs.


Assuntos
Carcinoma Basocelular/diagnóstico por imagem , Dermoscopia , Fluoroscopia , Melanoma/diagnóstico por imagem , Nevo Pigmentado/diagnóstico por imagem , Neoplasias Cutâneas/diagnóstico por imagem , Diagnóstico Diferencial , Fluorescência , Humanos , Melanócitos , Microscopia de Fluorescência por Excitação Multifotônica , Sensibilidade e Especificidade , Pele/patologia
14.
PLoS Med ; 17(7): e1003163, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32658890

RESUMO

BACKGROUND: Tissue advanced glycation end product (AGE) accumulation has been proposed as a marker of cumulative metabolic stress that can be assessed noninvasively by measurement of skin autofluorescence (SAF). In persons on haemodialysis, SAF is an independent risk factor for cardiovascular events (CVEs) and all-cause mortality (ACM), but data at earlier stages of chronic kidney disease (CKD) are inconclusive. We investigated SAF as a risk factor for CVEs and ACM in a prospective study of persons with CKD stage 3. METHODS AND FINDINGS: Participants with estimated glomerular filtration rate (eGFR) 59 to 30 mL/min/1.73 m2 on two consecutive previous blood tests were recruited from 32 primary care practices across Derbyshire, United Kingdom between 2008 and 2010. SAF was measured in participants with CKD stage 3 at baseline, 1, and 5 years using an AGE reader (DiagnOptics). Data on hospital admissions with CVEs (based on international classification of diseases [ICD]-10 coding) and deaths were obtained from NHS Digital. Cox proportional hazards models were used to investigate baseline variables associated with CVEs and ACM. A total of 1,707 of 1,741 participants with SAF readings at baseline were included in this analysis: The mean (± SD) age was 72.9 ± 9.0 years; 1,036 (60.7%) were female, 1,681 (98.5%) were of white ethnicity, and mean (±SD) eGFR was 53.5 ± 11.9 mL/min/1.73 m2. We observed 319 deaths and 590 CVEs during a mean of 6.0 ± 1.5 and 5.1 ± 2.2 years of observation, respectively. Higher baseline SAF was an independent risk factor for CVEs (hazard ratio [HR] 1.12 per SD, 95% CI 1.03-1.22, p = 0.01) and ACM (HR 1.16, 95% CI 1.03-1.30, p = 0.01). Additionally, increase in SAF over 1 year was independently associated with subsequent CVEs (HR 1.11 per SD, 95% CI 1.00-1.22; p = 0.04) and ACM (HR 1.24, 95% CI 1.09-1.41, p = 0.001). We relied on ICD-10 codes to identify hospital admissions with CVEs, and there may therefore have been some misclassification. CONCLUSIONS: We have identified SAF as an independent risk factor for CVE and ACM in persons with early CKD. These findings suggest that interventions to reduce AGE accumulation, such as dietary AGE restriction, may reduce cardiovascular risk in CKD, but this requires testing in prospective randomised trials. Our findings may not be applicable to more ethnically diverse or younger populations.


Assuntos
Doenças Cardiovasculares/fisiopatologia , Produtos Finais de Glicação Avançada/metabolismo , Insuficiência Renal Crônica/mortalidade , Pele/química , Idoso , Idoso de 80 Anos ou mais , Feminino , Fluorescência , Taxa de Filtração Glomerular , Humanos , Estimativa de Kaplan-Meier , Masculino , Modelos de Riscos Proporcionais , Estudos Prospectivos , Insuficiência Renal Crônica/complicações , Fatores de Risco
15.
Huan Jing Ke Xue ; 41(2): 905-913, 2020 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608752

RESUMO

The Pinus tabulaeformis plantation on the Loess Plateau was selected as the research site to study the changes of soil water-soluble carbon and nitrogen content and components of soil dissolved organic matter (SDOM) under different management measures (litter removal, young Pinus tabulaeformis forest, shrubs, grassland). The uncleared Pinus tabulaeformis plantation was used as the control. Results show that the soil water-soluble organic carbon content of shrubs and young Pinus tabulaeformis forests was significantly higher than that in other management measures. The content of soil water-soluble organic carbon decreased with an increase in soil depth, whereas soil water-soluble organic carbon/soil organic carbon (WSOC/SOC) increased. The change of soil water-soluble nitrogen content corresponded to that of water-soluble carbon. The content of soil water-soluble nitrogen content in the young Pinus tabulaeformis forest was higher than that of other management measures, and generally decreased with an increase in depth. Different management measures have significant effects on SDOM components. Based on three-dimensional fluorescence spectroscopy combined with parallel factor (EEM-PARAFAC) analysis, four components of SDOM are identified, which are mainly divided into categories, humus, protein-like, and soluble microbial metabolites in three major categories, among which the main component of the SDOM is the rich acid humus, and the highest content in the soil of the young forest of Pinus tabulaeformis is rich acid. The results suggested that management measures had certain effects on soil water-soluble carbon and nitrogen content as well as SDOM components, especially in young Pinus tabulaeformis forests and shrubs. The young Pinus tabulaeformis forest and shrubs increased the content of soil water-soluble organic carbon and water-soluble nitrogen, enhanced their ability to migrate and transform in the soil, and changed the structural composition of soil organic matter, hence enhancing the degree of humification and further improving soil quality.


Assuntos
Carbono/análise , Nitrogênio/análise , Pinus , Solo/química , China , Fluorescência , Florestas , Água
16.
BMC Bioinformatics ; 21(1): 291, 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32640980

RESUMO

BACKGROUND: A recently proposed method for estimating qPCR amplification efficiency E analyzes fluorescence intensity ratios from pairs of points deemed to lie in the exponential growth region on the amplification curves for all reactions in a dilution series. This method suffers from a serious problem: The resulting ratios are highly correlated, as they involve multiple use of the raw data, for example, yielding ~ 250 E estimates from ~ 25 intensity readings. The resulting statistics for such estimates are falsely optimistic in their assessment of the estimation precision. RESULTS: Monte Carlo simulations confirm that the correlated pairs method yields precision estimates that are better than actual by a factor of two or more. This result is further supported by estimating E by both pairwise and Cq calibration methods for the 16 replicate datasets from the critiqued work, and then comparing the ensemble statistics for these methods. CONCLUSION: Contrary to assertions in the proposing work, the pairwise method does not yield E estimates a factor of 2 more precise than estimates from Cq calibration fitting (the standard curve method). On the other hand, the statistically correct direct fit of the data to the model behind the pairwise method can yield E estimates of comparable precision. Ways in which the approach might be improved are discussed briefly.


Assuntos
Reação em Cadeia da Polimerase em Tempo Real , Correlação de Dados , Fluorescência , Método de Monte Carlo
17.
PLoS Biol ; 18(7): e3000750, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32667916

RESUMO

Photoreceptors are specialized cells devoted to the transduction of the incoming visual signals. Rods are able also to shed from their tip old disks and to synthesize at the base of the outer segment (OS) new disks. By combining electrophysiology, optical tweezers (OTs), and biochemistry, we investigate mechanosensitivity in the rods of Xenopus laevis, and we show that 1) mechanosensitive channels (MSCs), transient receptor potential canonical 1 (TRPC1), and Piezo1 are present in rod inner segments (ISs); 2) mechanical stimulation-of the order of 10 pN-applied briefly to either the OS or IS evokes calcium transients; 3) inhibition of MSCs decreases the duration of photoresponses to bright flashes; 4) bright flashes of light induce a rapid shortening of the OS; and 5) the genes encoding the TRPC family have an ancient association with the genes encoding families of protein involved in phototransduction. These results suggest that MSCs play an integral role in rods' phototransduction.


Assuntos
Transdução de Sinal Luminoso , Mecanotransdução Celular , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Xenopus laevis/metabolismo , Animais , Cálcio/metabolismo , Fluorescência , Luz , Transdução de Sinal Luminoso/efeitos da radiação , Mecanotransdução Celular/efeitos da radiação , Família Multigênica , Estimulação Luminosa , Células Fotorreceptoras Retinianas Bastonetes/efeitos da radiação , Canais de Cátion TRPC/genética , Proteínas de Xenopus/genética
18.
Int J Nanomedicine ; 15: 4125-4138, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606668

RESUMO

Purpose: To investigate the effect and mechanism of macrophage membrane-coated nanoparticles (M-NPs) on hepatic ischemia-reperfusion injury (I/RI) caused by orthotopic liver transplantation. In addition, the advantages of TLR4+/M-NPs compared to M-NPs are discussed. Materials and Methods: We prepared biomimetic M-NPs and identified their characteristics. M-NPs were injected into an SD rat model of orthotopic liver transplantation, and the anti-inflammatory and anti-I/RI activities of M-NPs were studied in vivo and in vitro. In addition, we overexpressed macrophage membrane Toll-like receptor 4 (TLR4) in vitro and prepared TLR4+/M-NPs. Then, we assessed the characteristics and advantages of TLR4+/M-NPs. Results: The M-NPs neutralized endotoxin, inhibited the overactivation of Kupffer cells (KCs) and suppressed the secretion of inflammatory factors by inhibiting the endotoxin-mediated TLR4/MyD88/IRAK1/NF-κB signaling pathway. In an orthotopic liver transplantation model in SD rats, M-NPs showed significant therapeutic efficacy by neutralizing endotoxin and suppressing the secretion of inflammatory factors. Moreover, overexpression of TLR4 on the macrophage membrane by using a TLR4+-plasmid in vitro effectively reduced the amount of M-NPs needed to neutralize an equivalent dose of endotoxin, reducing the potential risks of NP overuse. Conclusion: This study indicates that M-NPs can effectively alleviate I/RI induced by liver transplantation.


Assuntos
Membrana Celular/metabolismo , Endotoxinas/metabolismo , Transplante de Fígado/efeitos adversos , Fígado/irrigação sanguínea , Macrófagos/metabolismo , Nanopartículas/química , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/terapia , Animais , Anti-Inflamatórios/farmacologia , Fluorescência , Lipopolissacarídeos/farmacologia , Fígado/efeitos dos fármacos , Fígado/patologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Masculino , Camundongos , Nanopartículas/ultraestrutura , Células RAW 264.7 , Ratos Sprague-Dawley , Receptor 4 Toll-Like/metabolismo
19.
Int J Nanomedicine ; 15: 4289-4309, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606678

RESUMO

Objective: To construct prostate-specific membrane antigen (PSMA)-targeting, indocyanine green (ICG)-loaded nanobubbles (NBs) for multimodal (ultrasound, photoacoustic and fluorescence) imaging of prostate cancer. Methods: The mechanical oscillation method was used to prepare ICG-loaded photoacoustic NBs (ICG NBs). Then, PSMA-binding peptides were connected to the surface of ICG NBs using the biotin-avidin method to make targeted photoacoustic NBs, namely, PSMAP/ICG NBs. Their particle sizes, zeta potentials, and in vitro ultrasound, photoacoustic and fluorescence imaging were examined. Confocal laser scanning microscopy and flow cytometry were used to detect the binding ability of the PSMAP/ICG NBs to PSMA-positive LNCaP cells, C4-2 cells, and PSMA-negative PC-3 cells. The multimodal imaging effects of PSMAP/ICG NBs and ICG NBs were compared in nude mouse tumor xenografts. Results: The particle size of the PSMAP/ICG NBs was approximately 457.7 nm, and the zeta potential was approximately -23.5 mV. Both confocal laser scanning microscopy and flow cytometry confirmed that the PSMAP/ICG NBs could specifically bind to both LNCaP and C4-2 cells, but they rarely bound to PC-3 cells. The ultrasound, photoacoustic and fluorescence imaging intensities of the PSMAP/ICG NBs in vitro positively correlated with their concentrations. The ultrasound and photoacoustic imaging effects of the PSMAP/ICG NBs in LNCaP and C4-2 tumor xenografts were significantly enhanced compared with those in PC-3 tumor xenografts, which were characterized by a significantly increased duration of ultrasound enhancement and heightened photoacoustic signal intensity (P < 0.05). Fluorescence imaging showed that PSMAP/ICG NBs could accumulate in LNCaP and C4-2 tumor xenografts for a relatively long period. Conclusion: The targeted photoacoustic nanobubbles prepared in this study can specifically bind to PSMA-positive prostate cancer cells and have the ability to enhance ultrasound, photoacoustic and fluorescence imaging of PSMA-positive tumor xenografts. Photoacoustic imaging could visually display the intensity of the red photoacoustic signal in the tumor region, providing a more intuitive imaging modality for targeted molecular imaging. This study presents a potential multimodal contrast agent for the accurate diagnosis and assessment of prostate cancer.


Assuntos
Verde de Indocianina/química , Nanopartículas/química , Imagem Óptica , Técnicas Fotoacústicas , Neoplasias da Próstata/diagnóstico por imagem , Ultrassonografia , Animais , Linhagem Celular Tumoral , Meios de Contraste/química , Fluorescência , Humanos , Masculino , Camundongos Nus , Nanopartículas/ultraestrutura , Tamanho da Partícula , Peptídeos/metabolismo , Antígeno Prostático Específico/metabolismo , Neoplasias da Próstata/terapia , Ligação Proteica
20.
Food Chem ; 329: 127142, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32521426

RESUMO

In this work, we investigate alternative quantification methods based on optical spectroscopy and variable selection approach, using as a case study the aging process of cachaça. The cachaça was aged in an Amburana barrel and the samples were analyzed with a traditional analytical method for total phenolic quantification (Folin-Ciocalteu), with 2-D fluorescence and infrared spectroscopy. We applied a methodology based on Ant Colony Optimization to optimize variable selection and model fitting to predict total phenolic content. Our results demonstrated that fluorescence spectroscopy was more sensitive than IR in the quantification of total phenolic compounds for both global and local models, presenting good results (R2 superior to 0.979), significantly reducing the number of original variable (1995) for only 4 pairs of Ex/Em. Variable selection combined with spectroscopy reveals potential because this technique eliminates the need for sample preparation and allows the construction of customized sensors for application in the food industry.


Assuntos
Bebidas Alcoólicas/análise , Fenóis/química , Fluorescência , Extratos Vegetais/química , Espectrometria de Fluorescência , Espectrofotometria Infravermelho , Fatores de Tempo
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