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1.
Nat Commun ; 11(1): 4569, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917892

RESUMO

Eumelanin is a brown-black biological pigment with sunscreen and radical scavenging functions important to numerous organisms. Eumelanin is also a promising redox-active material for energy conversion and storage, but the chemical structures present in this heterogeneous pigment remain unknown, limiting understanding of the properties of its light-responsive subunits. Here, we introduce an ultrafast vibrational fingerprinting approach for probing the structure and interactions of chromophores in heterogeneous materials like eumelanin. Specifically, transient vibrational spectra in the double-bond stretching region are recorded for subsets of electronic chromophores photoselected by an ultrafast excitation pulse tuned through the UV-visible spectrum. All subsets show a common vibrational fingerprint, indicating that the diverse electronic absorbers in eumelanin, regardless of transition energy, contain the same distribution of IR-active functional groups. Aggregation of chromophores diverse in oxidation state is the key structural property underlying the universal, ultrafast deactivation behavior of eumelanin in response to photoexcitation with any wavelength.


Assuntos
Melaninas/química , Vibração , Oxirredução , Espectrofotometria Infravermelho/métodos , Protetores Solares
2.
Medicine (Baltimore) ; 99(30): e21302, 2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32791715

RESUMO

INTRODUCTION: By detecting the metabolic difference of the Heart and Lung meridians, the present study aims to investigate the specificity of different meridians and verify whether functional near infrared spectroscopy is validated as an add-on technique to assist diagnosis of chronic obstructive pulmonary disease (COPD). METHODS AND ANALYSIS: The Lung and Heart meridians are chosen as the target for comparison; accordingly, 120 eligible participants will be included and divided into the COPD group, healthy control group, and healthy intervention group. Functional near infrared spectroscopy will be adopted to measure the metabolic characteristics of the Heart and Lung meridians. On one hand, the specificity of the meridian-visceral association will be investigated by comparing the metabolic difference in the Heart and Lung meridians between the healthy control group and COPD group. On the other hand, the specificity of site-to-site association will be determined by comparing the metabolic change between the 2 meridians that induced by moxibustion in the Heart meridian and Lung meridian, respectively, in the healthy control group. The primary outcome will be regional oxygen saturation of corresponding regions along the Heart and Lung meridians. TRIAL REGISTRATION: ClinicalTrials.gov NCT04046666.


Assuntos
Coração/fisiologia , Pulmão/metabolismo , Moxibustão/métodos , Doença Pulmonar Obstrutiva Crônica/terapia , Espectrofotometria Infravermelho/métodos , Pontos de Acupuntura , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Voluntários Saudáveis , Humanos , Masculino , Meridianos , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Oxigênio/metabolismo , Estudos Prospectivos , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Sensibilidade e Especificidade
3.
Nat Commun ; 11(1): 4348, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859910

RESUMO

The interpretation of molecular vibrational spectroscopic signals in terms of atomic motion is essential to understand molecular mechanisms and for chemical characterization. The signals are usually assigned after harmonic normal mode analysis, even if molecular vibrations are known to be anharmonic. Here we obtain the quantum anharmonic vibrational eigenfunctions of the 11-atom protonated glycine molecule and we calculate the density distribution of its nuclei and its geometry parameters, for both the ground and the O-H stretch excited states, using our semiclassical method based on ab initio molecular dynamics trajectories. Our quantum mechanical results describe a molecule elongated and more flexible with respect to what previously thought. More importantly, our method is able to assign each spectral peak in vibrational spectroscopy by showing quantitatively how normal modes involving different functional groups cooperate to originate that spectroscopic signal. The method will possibly allow for a better rationalization of experimental spectroscopy.


Assuntos
Glicina/química , Simulação de Dinâmica Molecular , Vibração , Estrutura Molecular , Teoria Quântica , Espectrofotometria Infravermelho , Termodinâmica
4.
PLoS One ; 15(8): e0238149, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32833991

RESUMO

As a characteristic edible fungus with a high nutritional value and medicinal effect, the Bachu mushroom has a broad market. To distinguish among Bachu mushrooms with high value and other fungi effectively and accurately, as well as to explore a universal identification method, this study proposed a method to identify Bachu mushrooms by Fourier Transform Infrared Spectroscopy (FT-IR) combined with machine learning. In this experiment, two kinds of common edible mushrooms, Lentinus edodes and club fungi, were selected and classified with Bachu mushrooms. Due to the different distribution of nutrients in the caps and stalks, the caps and stalks were studied in this experiment. By comparing the average normalized infrared spectra of the caps and stalks of the three types of fungi, we found differences in their infrared spectra, indicating that the latter can be used to classify and identify the three types of fungi. We also used machine learning to process the spectral data. The overall steps of data processing are as follows: use partial least squares (PLS) to extract spectral features, select the appropriate characteristic number, use different classification algorithms for classification, and finally determine the best algorithm according to the classification results. Among them, the basis of selecting the characteristic number was the cumulative variance interpretation rate. To improve the reliability of the experimental results, this study also used the classification results to verify the feasibility. The classification algorithms used in this study were the support vector machine (SVM), backpropagation neural network (BPNN) and k-nearest neighbors (KNN) algorithm. The results showed that the three algorithms achieved good results in the multivariate classification of the caps and stalks data. Moreover, the cumulative variance explanation rate could be used to select the characteristic number. Finally, by comparing the classification results of the three algorithms, the classification effect of KNN was found to be the best. Additionally, the classification results were as follows: according to the caps data classification, the accuracy was 99.06%; according to the stalks data classification, the accuracy was 99.82%. This study showed that infrared spectroscopy combined with a machine learning algorithm has the potential to be applied to identify Bachu mushrooms and the cumulative variance explanation rate can be used to select the characteristic number. This method can also be used to identify other types of edible fungi and has a broad application prospect.


Assuntos
Agaricales/classificação , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Algoritmos , Confiabilidade dos Dados , Análise Discriminante , Fungos/classificação , Análise dos Mínimos Quadrados , Aprendizado de Máquina , Redes Neurais de Computação , Análise de Componente Principal/métodos , Reprodutibilidade dos Testes , Cogumelos Shiitake , Espectrofotometria Infravermelho/métodos , Máquina de Vetores de Suporte
5.
Opt Express ; 28(12): 18479-18492, 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32680046

RESUMO

Biomolecule sensing plays an important role in both fundamental biological studies and medical diagnostic applications. Infrared (IR) spectroscopy presents opportunities for sensing biomolecules as it allows their fingerprints to be determined by directly measuring their absorption spectra. However, the detection of biomolecules at low concentrations is difficult with conventional IR spectroscopy due to signal-to-noise considerations. This has led to recent interest on the use of nanostructured surfaces to boost the signals from biomolecules in a method termed surface enhanced infrared spectroscopy. So far, efforts have largely involved the use of metallic nanoantennas (which produce large field enhancement) or graphene nanostructures (which produce strong field confinement and provide electrical tunability). Here, we propose a nanostructured surface that combines the large field enhancement of metallic nanoantennas with the strong field confinement and electrical tunability of graphene plasmons. Our device consists of an array of plasmonic nanoantennas and graphene nanoslits on a resonant substrate. We perform systematic electromagnetic simulations to quantify the sensing performance of the proposed device and show that it outperforms designs in which only plasmons from metallic nanoantennas or plasmons from graphene are utilized. These investigations consider the model system of a representative protein-goat anti-mouse immunoglobulin G (IgG) - in monolayer or sub-monolayer form. Our findings provide guidance for future biosensors for the sensitive quantification and identification of biomolecules.


Assuntos
Grafite , Nanopartículas Metálicas , Espectrofotometria Infravermelho/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Desenho de Equipamento/métodos , Proteínas/análise , Ressonância de Plasmônio de Superfície/métodos
6.
Food Chem ; 332: 127383, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615383

RESUMO

This study represents a rapid and non-destructive approach based on mid-infrared (MIR) spectroscopy, time domain nuclear magnetic resonance (TD-NMR), and machine learning classification models (ML) for monitoring soluble pectin content (SPC) changes in orange juice. Current reference methods of SPC in orange juice are laborious, requiring several extractions with successive adjustments hindering rapid process intervention. 109 fresh orange juices samples, representing different harvests, were analysed using MIR, TD-NMR and reference method. Unsupervised algorithms were applied for natural clustering of MIR and TD-NMR data in two groups. Analyses of variance of the two MIR and TD-NMR datasets show that only the MIR groups were different at 95% confidence for SPC average values. This approach allows build classification models based on MIR data achieving 85% and 89% of accuracy. Results demonstrate that MIR/ML can be a suitable strategy for the quick assessment of SPC trends in orange juices.


Assuntos
Citrus sinensis/química , Sucos de Frutas e Vegetais/análise , Aprendizado de Máquina , Pectinas/química , Citrus sinensis/metabolismo , Análise por Conglomerados , Humanos , Espectroscopia de Ressonância Magnética , Pectinas/metabolismo , Análise de Componente Principal , Espectrofotometria Infravermelho
7.
Int J Nanomedicine ; 15: 3497-3509, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32547009

RESUMO

Purpose: The existing treatment modalities for rheumatoid arthritis are less effective and safe, therefore it is essential to develop new treatments that particularly target the inflamed joints with decreased off-target side-effects. The current study proposes a nanoparticle-based therapeutic approach to target the anti-oxidant defense system of arthritic Balb/c mice. Methods: Biogenic selenium nanoparticles (SeNPs) were synthesized by using Trachyspermum ammi seed extract and were evaluated for their toxicological, as well as their therapeutic potential in collagen-induced arthritic mice. Results: The tested doses of SeNPs had no significant toxic effects on liver, kidney, spleen, and serum biochemical parameters in comparison to healthy mice. The SeNPs treatment reduced the disease severity, as demonstrated by decreased paw edema along with reduced lymphocytic cellular infiltration in the histopathological findings. SeNPs also revealed dose-independent improvement in the redox state of inflamed synovium by significantly improving the activity of antioxidant enzymes in comparison to the arthritic controls. Conclusion: It is therefore concluded that nano-selenium in combination with TAE extract showed enhanced therapeutic efficacy as compared to their individual effects.


Assuntos
Antirreumáticos/uso terapêutico , Apiaceae/química , Artrite Reumatoide/tratamento farmacológico , Nanopartículas/química , Selênio/toxicidade , Selênio/uso terapêutico , Animais , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Antirreumáticos/farmacologia , Artrite Reumatoide/patologia , Peso Corporal/efeitos dos fármacos , Catalase/metabolismo , Bovinos , Edema/patologia , Feminino , Fígado/efeitos dos fármacos , Fígado/enzimologia , Camundongos Endogâmicos BALB C , Nanopartículas/administração & dosagem , Nanopartículas/ultraestrutura , Oxirredução , Extratos Vegetais/química , Selênio/administração & dosagem , Selênio/farmacologia , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Baço/efeitos dos fármacos , Baço/patologia
8.
Nat Commun ; 11(1): 2945, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32522983

RESUMO

The chemical and structural properties of biomolecules determine their interactions, and thus their functions, in a wide variety of biochemical processes. Innovative imaging methods have been developed to characterise biomolecular structures down to the angstrom level. However, acquiring vibrational absorption spectra at the single molecule level, a benchmark for bulk sample characterization, has remained elusive. Here, we introduce off-resonance, low power and short pulse infrared nanospectroscopy (ORS-nanoIR) to allow the acquisition of infrared absorption spectra and chemical maps at the single molecule level, at high throughput on a second timescale and with a high signal-to-noise ratio (~10-20). This high sensitivity enables the accurate determination of the secondary structure of single protein molecules with over a million-fold lower mass than conventional bulk vibrational spectroscopy. These results pave the way to probe directly the chemical and structural properties of individual biomolecules, as well as their interactions, in a broad range of chemical and biological systems.


Assuntos
Nanotecnologia/métodos , Espectrofotometria Infravermelho/métodos , Biofísica , Conformação Molecular
9.
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
11.
PLoS One ; 15(5): e0232765, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365099

RESUMO

The water-soluble fullerenols are novel carbon-based nanomaterials with unique properties, which afford them with wide agricultural applications. Iron (Fe) deficiency is the most common and widespread nutrition disorder affecting plants. Foliar Fe treatments of plants have been carried out with solutions devoid of fullerenol. In this study, the role of fullerenol [C60(OH)22-24] in alleviation of Fe deficiency in Cucumis sativus (a Strategy I plant) via foliar fertilization was investigated. Cucumber plants were grown hydroponically, either with (Fe) or in Fe-free (-Fe) nutrient solution. The following foliar spray treatments were applied: fullerenol at final concentrations of 1 (F1) and 10 (F10) mg L-1; Fe(II)SO4·7H2O; Fe(II)-EDTA (ethylenediaminetetraacetic acid); and Fe(II)-F1 and Fe(II)-F10. The best used compound was a combination of Fe(II)-sulfate with fullerenol, especially Fe-F1. The addition of fullerenol to Fe(II)-sulfate solutions significantly increased leaf-active Fe (extracted by an Fe(II) chelator) and re-greening at the site of application. The fullerenol-induced mutual influences did not appear when fullerenol was sprayed alone, suggesting a beneficial role of Fe(II)-fullerenol interactions in the penetration of Fe(II) in the leaves and re-greening under Fe-limited conditions. The results are of importance to enhancing the potential of foliar Fe fertilization as the commonly used strategy for ameliorating Fe deficiency and improving crop yield and quality.


Assuntos
Cucumis sativus/metabolismo , Fulerenos/farmacologia , Ferro/deficiência , Folhas de Planta/metabolismo , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Clorofila/metabolismo , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/crescimento & desenvolvimento , Hidroponia , Tamanho da Partícula , Folhas de Planta/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Espectrofotometria Infravermelho , Eletricidade Estática
12.
Nat Commun ; 11(1): 2664, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471982

RESUMO

Controlling the chemical glycosylation reaction remains the major challenge in the synthesis of oligosaccharides. Though 1,2-trans glycosidic linkages can be installed using neighboring group participation, the construction of 1,2-cis linkages is difficult and has no general solution. Long-range participation (LRP) by distal acyl groups may steer the stereoselectivity, but contradictory results have been reported on the role and strength of this stereoelectronic effect. It has been exceedingly difficult to study the bridging dioxolenium ion intermediates because of their high reactivity and fleeting nature. Here we report an integrated approach, using infrared ion spectroscopy, DFT computations, and a systematic series of glycosylation reactions to probe these ions in detail. Our study reveals how distal acyl groups can play a decisive role in shaping the stereochemical outcome of a glycosylation reaction, and opens new avenues to exploit these species in the assembly of oligosaccharides and glycoconjugates to fuel biological research.


Assuntos
Química Computacional/métodos , Oligossacarídeos/síntese química , Compostos de Selênio/química , Configuração de Carboidratos , Galactose/química , Glucose/química , Glicosilação , Manose/química , Espectrofotometria Infravermelho
13.
AAPS PharmSciTech ; 21(5): 152, 2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32440782

RESUMO

The present study investigates concomitant processes of solid-state disordering and oxidation of simvastatin during milling. The separate dry ball milling of crystalline and amorphous powders of simvastatin were conducted at ambient temperature for 10 and 60 min each. The relative crystallinity was determined using X-ray scattering and oxidative degradation was analyzed using liquid chromatography. The physical and chemical transformations in the milled powder were evaluated using modulated differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy. The disordering during milling of the crystalline powder was found to progressively decrease the crystallinity. For the amorphous starting material, milling for 10 min induced a large extent of recrystallization, while milling for 60 min largely re-amorphized the powder. This solid-state disordering and/or ordering were accompanied by progressive air oxidation during milling. The infrared spectroscopic analysis revealed the molecular manifestations associated with the physicochemical transformations in the disordered solid states. The melting point of simvastatin depressed systematically with the increase in the degree of disorder as well as the degradation. The in situ cooling in DSC of milled samples from their molten state led to the formation of the co-amorphous phase between the drug and degradation products, which showed a consistent increase in glass transition temperature with the increase in the content of degradation products. The study overall demonstrates the solid-state re-ordering and disordering of crystalline and amorphous simvastatin accompanied by chemical degradation as the consequence of the mechano-activation.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/química , Sinvastatina/química , Varredura Diferencial de Calorimetria , Análise Diferencial Térmica , Composição de Medicamentos , Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Luz , Transição de Fase , Pós , Espalhamento de Radiação , Sinvastatina/administração & dosagem , Espectrofotometria Infravermelho , Raios X
14.
Acta Crystallogr D Struct Biol ; 76(Pt 4): 326-331, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32254056

RESUMO

The study of ion channels dates back to the 1950s and the groundbreaking electrophysiology work of Hodgin and Huxley, who used giant squid axons to probe how action potentials in neurons were initiated and propagated. More recently, several experiments using different structural biology techniques and approaches have been conducted to try to understand how potassium ions permeate through the selectivity filter of potassium ion channels. Two mechanisms of permeation have been proposed, and each of the two mechanisms is supported by different experiments. The key structural biology experiments conducted so far to try to understand how ion permeation takes place in potassium ion channels are reviewed and discussed. Protein crystallography has made, and continues to make, key contributions in this field, often through the use of anomalous scattering. Other structural biology techniques used to study the contents of the selectivity filter include solid-state nuclear magnetic resonance and two-dimensional infrared spectroscopy, both of which make clever use of isotopic labeling techniques, while molecular-dynamics simulations of ion flow through the selectivity filter have been enabled by the growing number of potassium ion channel structures deposited in the Protein Data Bank.


Assuntos
Simulação de Dinâmica Molecular , Canais de Potássio/química , Potássio/química , Cristalografia por Raios X , Marcação por Isótopo , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Estrutura Terciária de Proteína , Espalhamento de Radiação , Espectrofotometria Infravermelho
15.
Food Chem ; 322: 126709, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283376

RESUMO

This study elucidated the formation mechanism of calcium-indigo carmine (IC) complex. Parameters of the complex, such as Turbiscan stability index (TSI), yield and stoichiometric ratio (Ca to IC) were investigated. Isothermal titration calorimetry (ITC), UV/Visible spectrophotometry, infrared spectroscopy and Raman spectroscopy were used to explore the interaction between IC and Ca(II) during formation reaction and in the powdered lake. The TSI analysis and yield test suggested pH 7.0 as the most suitable pH to produce this complex. The conjugation between IC and Ca(II) was an exothermal reaction with increase of entropy (ΔH = -0.728 ± 0.11 kJ·mol-1 and ΔS = 66.55 ± 1.89 kJ·mol-1·K-1 at 25 °C). Both ITC and stoichiometric ratio test suggested one Ca atom tended to conjugate five IC molecules at ambient temperature when an adequate amount of Ca(II) appeared. Spectrometry techniques suggested that the sulfonic acid groups in IC formed coordination bonds with the Ca to construct the complex.


Assuntos
Cálcio/química , Corantes de Alimentos/química , Índigo Carmim/química , Calorimetria , Cor , Entropia , Espectrofotometria , Espectrofotometria Infravermelho
16.
Phys Chem Chem Phys ; 22(16): 8667-8671, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32270833

RESUMO

We study the relation between the macroscopic viscoelastic properties of aqueous hyaluronan polymer solutions and the molecular-scale dynamics of water using rheology measurements, differential dynamic microscopy, and polarization-resolved infrared pump-probe spectroscopy. We observe that the addition of hyaluronan to water leads to a slowing down of the reorientation of a fraction of the water molecules. Near pH 2.4, the viscosity of the hyaluronan solution reaches a maximum, while the number of slowed down water molecules reaches a minimum. This implies that the water molecules become on average more mobile when the solution becomes more viscous. This observation indicates that the increase in viscosity involves the expulsion of hydration water from the surfaces of the hyaluronan polymers, and a bundling of the hyaluronan polymer chains.


Assuntos
Biopolímeros/química , Géis/química , Ácido Hialurônico/química , Água/química , Concentração de Íons de Hidrogênio , Reologia , Espectrofotometria Infravermelho
17.
Chemistry ; 26(45): 10297-10306, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32275091

RESUMO

PhotoCORMs are light-triggered compounds that release CO for medical applications. Here, we apply laser spectroscopy in the gas phase to TryptoCORM, a known photoCORM that has been shown to destroy Escherichia coli upon visible-light activation. Our experiments allow us to map TryptoCORM's photochemistry across a wide wavelength range by using novel laser-interfaced mass spectrometry (LIMS). LIMS provides the intrinsic absorption spectrum of the photoCORM along with the production spectra of all of its ionic photoproducts for the first time. Importantly, the photoproduct spectra directly reveal the optimum wavelengths for maximizing CO ejection, and the extent to which CO ejection is compromised at redder wavelengths. A series of comparative studies were performed on TryptoCORM-CH3 CN which exists in dynamic equilibrium with TryptoCORM in solution. Our measurements allow us to conclude that the presence of the labile CH3 CN facilitates CO release over a wider wavelength range. This work demonstrates the potential of LIMS as a new methodology for assessing active agent release (e.g. CO, NO, H2 S) from light-activated prodrugs.


Assuntos
Monóxido de Carbono/química , Escherichia coli/química , Pró-Fármacos/química , Cor , Luz , Espectrofotometria Infravermelho
18.
J Dairy Sci ; 103(6): 5263-5269, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32307163

RESUMO

Milk fat content and fatty acid (FA) composition have great economic value to the dairy industry as they are directly associated with taste and chemical-physical characteristics of milk and dairy products. In addition, consumers' choices are not only based on the nutritional aspects of food, but also on products known to promote better health. Milk FA composition is also related to the metabolic status and physiological stages of cows and thus can also be used as indicator for other novel traits of interest (e.g., metabolic diseases and methane yield). Genetic selection is a promising alternative to manipulate milk FA composition. In this study, we aimed to (1) estimate time-dependent genetic parameters for 5 milk FA groups (i.e., short-chain, medium-chain, long-chain, saturated, and unsaturated) predicted based on milk mid-infrared spectroscopy, for Canadian Ayrshire and Jersey breeds, and (2) conduct a time-dependent, single-step genome-wide association study to identify genomic regions, candidate genes, and metabolic pathways associated with milk FA. We analyzed 31,709 test-day records of 9,648 Ayrshire cows from 268 herds, and 34,341 records of 11,479 Jersey cows from 883 herds. The genomic database contained a total of 2,330 Ayrshire and 1,019 Jersey animals. The average daily heritability ranged from 0.18 (long-chain FA) to 0.34 (medium-chain FA) in Ayrshire, and from 0.25 (long-chain and unsaturated FA) to 0.52 (medium-chain and saturated FA) in Jersey. Important genomic regions were identified in Bos taurus autosomes BTA3, BTA5, BTA12, BTA13, BTA14, BTA16, BTA18, BTA20, and BTA21. The proportion of the variance explained by 20 adjacent SNP ranged from 0.71% (saturated FA) to 1.11% (long-chain FA) in Ayrshire, and from 0.70% (unsaturated FA) to 3.09% (medium-chain FA) in Jersey cattle. Important candidate genes and pathways were also identified, such as the PTK2 and TRAPPC9 genes, associated with milk fat percentage, and HMGCS, FGF10, and C6 genes, associated with fertility traits and immune response. Our findings on the genetic parameters and candidate genes contribute to a better understanding of the genetic architecture of milk FA composition in Ayrshire and Jersey dairy cattle.


Assuntos
Cruzamento , Bovinos/genética , Ácidos Graxos/análise , Estudo de Associação Genômica Ampla/veterinária , Leite/química , Seleção Genética , Animais , Indústria de Laticínios , Feminino , Fenótipo , Espectrofotometria Infravermelho
19.
Chemosphere ; 252: 126413, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32197171

RESUMO

O3 and alkenes are important reactants in the formation of SOA in the atmosphere. The intermediates and reaction mechanism of ozonation of alkene is an important topic in atmospheric chemistry. In this study, the low-temperature matrix isolation was used to capture the intermediates such as Primary ozonides (POZs), Criegee Intermediates (CIs), and Secondary ozonides (SOZs) generated from ozonation of 2-methyl-1-butene (2M1B) and 2-methyl-2-butene (2M2B). The results have been identified by the vacuum infrared spectroscopy and theoretical calculation. Our results show that during the ozonation of asymmetric alkenes, two kinds of CIs and more than two kinds of SOZs were generated due to the different decomposition modes of POZs. The infrared absorption peaks of (CH3)2COO and CH3CH2C(CH3)OO for O-O telescopic vibration was determined to be 889 cm-1 and 913 cm-1, respectively. Using the merged jet method, it was found that a large amount of HCHO was produced during the ozonation of 2M1B, and glyoxal and methylglyoxal were produced in the ozonation of 2M2B. Our findings highlight the importance of asymmetric alkene ozonolysis reactions in producing CIs, further improving the understanding of the generation of CIs from ozonation of alkenes.


Assuntos
Alcenos/química , Modelos Químicos , Ozônio/química , Atmosfera , Compostos Heterocíclicos , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Phys Chem Chem Phys ; 22(17): 9195-9203, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32149285

RESUMO

Phytochromes are photosensory proteins in plants, fungi, and bacteria, which detect red- and far-red light. They undergo a transition between the resting (Pr) and photoactivated (Pfr) states. In bacterial phytochromes, the Pr-to-Pfr transition is facilitated by two intermediate states, called Lumi-R and Meta-R. The molecular structures of the protein in these states are not known and the molecular mechanism of photoconversion is not understood. Here, we apply transient infrared absorption spectroscopy to study the photocycle of the wild-type and Y263F mutant of the phytochrome from Deinococcus radiodurans (DrBphP) from nano- to milliseconds. We identify two sequentially forming Lumi-R states which differ in the local structure surrounding the carbonyl group of the biliverdin D-ring. We also find that the tyrosine at position 263 alters local structure and dynamics around the D-ring and causes an increased rate of Pfr formation. The results shed new light on the mechanism of light-signalling in phytochrome proteins.


Assuntos
Deinococcus/química , Deinococcus/genética , Modelos Moleculares , Fitocromo/química , Espectrofotometria Infravermelho , Proteínas de Bactérias/química , Transdução de Sinal Luminoso/genética , Mutação , Estrutura Terciária de Proteína
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