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1.
JACS Au ; 2(4): 853-864, 2022 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-35557757

RESUMO

Photosensitized energy transfer (EnT) phenomena occur frequently in a variety of photophysical and photochemical processes and have traditionally been treated with the donor-acceptor distance-dependent Förster and Dexter models. However, incorrect arguments and formulae were employed by ignoring energy resonance conditions and the selection rules of the state-to-state transition in special cases, especially for the sensitive intramolecular EnT of lanthanide complexes. Herein, we proposed an innovative model of energy-degeneracy-crossing-controlled EnT, which can be experimentally confirmed by time-resolved two-dimensional photoluminescence measurements. The computationally determined energy resonance region provides the most effective channel to achieve metal-to-ligand EnT beyond the distance-dependent model and sensitively bifurcates into symmetry-allowed or -forbidden channels for some representative europium antenna complexes. The outcomes of the multidisciplinary treatment contribute to a complementary EnT model that can be tuned by introducing a phosphorescence modulator and altering the antenna-related parameters of the ligand-centered energy level of the 3ππ* state and its spin-orbit coupling for the 3ππ* → S0 * transition through mechanism-guided crystal engineering and should motivate further development of mechanistic models and applications.

2.
Sci Total Environ ; 807(Pt 1): 150772, 2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-34619207

RESUMO

The flood storage of lakes and reservoirs plays an important role in flood regulation and control in floodplains. However, the flood storage capacity of lakes and reservoirs is ineffectively quantified at the basin scale due to the limited access to in-situ data and poor quality of optical satellite images in flooding seasons. To address this, taking a typical floodplain basin (the Poyang Lake basin) in the Yangtze as a study case, radar satellite data combined with measured bathymetry and digital elevation model data were utilized to reconstruct the time series of the water inundation area and water storage change of all lakes and reservoirs larger than 1 km2 during the once-in-a-generation flood event that occurred in 2020 (termed as the 2020 flood event hereafter). Results show that the flood storage capacity of Poyang Lake can reach the maximum at 12.18 Gt, and that for other lakes and reservoirs within the basin is approximately 2.95 Gt. It indicates a total flood-storage capacity of 15.13 Gt for the basin-scale lakes and reservoirs, approximately accounting for 45.02% of the terrestrial water storage change of the basin. The storage capacity of Poyang Lake was approximately four times larger than the entirety of other lakes and reservoirs in the basin despite that its maximum water inundation area is in the proportion of 2.58 times other water bodies. This finding indicates that the Poyang Lake provided the dominant contribution to flood storage among all the lakes and reservoirs in the basin. This study introduced a remote sensing approach to quantify the flood storage capacity of basin-scale lakes and reservoirs at high spatial and temporal resolutions during the flood event, which could fill the insufficiently-quantified knowledge about dynamics of lakes and reservoirs in areas lacking full-covered in-situ data records. This study also helps to offer a quantitative basis to improve flood forecasting and control for the public authority, stakeholders, and decision-makers.


Assuntos
Inundações , Lagos , China , Monitoramento Ambiental , Tecnologia de Sensoriamento Remoto , Estações do Ano , Água
3.
Artigo em Inglês | MEDLINE | ID: mdl-34360365

RESUMO

Knowledge of dam construction in floodplain systems and its hydrodynamic effects plays a critical role in managing various kinds of floodplains. This study uses 3D floodplain hydrodynamic modeling to explore the possible effects of a proposed hydraulic project in Poyang Lake (PLHP) on the hydrodynamics, exemplified by a large floodplain system. Simulations showed that the water levels across most lake regions presented more significant changes than in the floodplain areas during the study period. The increased water levels upstream from the PLHP (~1.0 m) were distinctly higher than that downstream (~0.1 m). The PLHP may decrease the magnitude of the water velocities in the main channels of the lake, whereas velocities may experience mostly minor changes in the floodplains, depending upon the altered flow dynamics and transport. On average, the water temperature may exhibit mostly minor changes (~<1.0 °C) for both the horizontal and vertical scales within the flood-pulse-influenced lake system. Additionally, the model results indicated that the outflow process caused by the PLHP may be altered from the natural discharge into the Yangtze River to frequent backflow events during the storage period, demonstrating the non-negligible effect of the PLHP on the water supply for the downstream Yangtze River in the future.


Assuntos
Hidrodinâmica , Lagos , China , Hidrologia , Rios , Estações do Ano
4.
Water Res ; 201: 117253, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119966

RESUMO

Continual and accelerating declines in hydrological connectivity threaten ecosystem processes, biodiversity, and services throughout the world. Therefore, there is an increasing demand for user-driven tools that assess hydrological connectivity from an effective perspective. We developed the Connectivity ASsessment Tool 1.0 (CAST1.0), which takes the threshold behaviors of focal ecological indicators into account, allows quantifying effective hydrological connectivity and its regime shift. We illustrate the use of CAST1.0 for the case of Poyang Lake, China. It was found that the response of effective hydrological connectivity to inundation depth, flow velocity, and water temperature follows a dynamic threshold effect. The evaluation of connected objects based on specific niches provides a valuable metric for recognizing potential habitat patches and links. This study provides a sound basis for assessing hydrological connectivity in a meaningful way, promising to provide novel insights into maintaining and restoring biodiversity and associated ecosystem services around the world.


Assuntos
Ecossistema , Hidrologia , Biodiversidade , China , Lagos
5.
J Phys Chem Lett ; 12(19): 4658-4665, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-33978423

RESUMO

Low concentrations of carbon monoxide (CO) can play vital roles in pharmacological and physiological functions in the human body. The transition-metal carbonyl complexes of the tricarbonyldichlororuthenium(II) dimer [Ru2(CO)6Cl4 (CORM-2)] were proposed as CO-releasing molecules (CORMs) to improve the delivery efficiency of CO for therapeutic effects. The accurate identification of final products for CORMs in solution and the detailed mechanisms of the release of CO were the essential prerequisite for its effective physiological application, which have been deficient. In this study, utilizing the cutting-edge two-dimensional (2D) IR spectroscopy, with the intrinsic vibrational modes and the coupling information on dynamics of intramolecular vibrational energy redistribution (IVR), the final products of A, B, C, and E are accurately identified when CORM-2 is dissolved in dimethyl sulfoxide (DMSO). Furthermore, with the clues on intermolecular interaction and chemical exchange dynamics between different products, the transformations between different products are also directly characterized for the first time. These findings challenge the results from the classic 1D spectroscopic pattern, and they evidently demonstrated that the release of CO from CORM-2 in DMSO was slow and complicated with multiple reaction pathways. Combining with DFT simulations, the detailed mechanisms of release of CO for CORM-2 dissolved in DMSO are schematically proposed, which can significantly contribute to its drug optimization and pharmacological as well as physiological applications.

6.
Int J Biol Macromol ; 183: 295-304, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33894258

RESUMO

In order to take full advantage of the gastrointestinal digestive function, the effects of S-type ultrasound-assisted sodium bisulfite (UASB) pretreatment on the preparation of cholesterol-lowering peptide precursors derived from soybean protein were investigated and the structural characterizations of pretreated proteins were explored. UASB pretreatment with the operational mode of mono-frequency ultrasound at 28 kHz, ultrasonic power density of 200 W/L and ultrasonic time of 50 min exhibited the highest cholesterol-lowering activity (56.90%) of soybean protein hydrolysates (SPH) after simulated gastrointestinal digestion, which increased by 87.17% compared to the control. Under these conditions, the peptide content of SPH after simulated gastrointestinal digestion was not significantly different (p > 0.05) compared to the control. Further FTIR analysis showed that UASB pretreatment increased ß-turn and ß-sheet content and decreased α-helix and random coil content. The changes in the surface hydrophobicity and microstructures of soybean protein indicated that UASB pretreatment loosened soybean protein structure and exposed more hydrophobic groups. SDS-PAGE indicated that the restriction sites changed after UASB pretreatment. In conclusion, UASB pretreatment is an efficient method for the preparation of cholesterol-lowering peptide precursors.


Assuntos
Anticolesterolemiantes/química , Peptídeos/química , Hidrolisados de Proteína/química , Proteínas de Soja/química , Sulfitos/química , Ondas Ultrassônicas , Animais , Humanos , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Water Res ; 195: 117005, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33714014

RESUMO

Recent years, the hydrological connectivity has gained popularity in various research fields, however, its definition and threshold effects at a system scale have not received adequate attention. The current research proposes a promising framework to refine the concept of surface hydrological connectivity by combining hydrodynamic modeling experiments, threshold effects and geostatistical connectivity analysis, exemplified by the flood-pulse-influenced Poyang Lake floodplain system (China). To enhance the inherent linkage between hydrological connectivity and eco-environments, total connectivity (TC), general connectivity (GC), and effective connectivity (EC) were proposed to refine the metrics of hydrological connectivity. The results show that substantial differences between the three connectivity metrics are observed for all target directions, demonstrating that the joint role of water depth and flow velocity may produce more dynamic and complex influences on EC than the other two metrics of TC and GC. Topographically, the connectivity objects/areas within the flood pulse system reveal that the floodplain is a more sensitive area than the lake's main flow channels under different connectivity conditions. The modelling experimental studies show that variations in water depth thresholds are more likely to have a strong effect on connectivity for the dry, rising, and falling limbs, rather than the flooding period, while the flow velocity may exert an opposite threshold effect. The lake-floodplain system is characterized by a dynamic threshold behavior, with seasonally varying water depth and velocity thresholds. This study highlights the importance of redefined connectivity concept for facilitating scientific communication by combining hydrodynamic thresholds and offering recommendations for future connectivity assessments using our proposed metrics of TC, GC, and EC.


Assuntos
Hidrologia , Lagos , China , Inundações , Hidrodinâmica
8.
Angew Chem Int Ed Engl ; 60(20): 11143-11147, 2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-33644946

RESUMO

While two-dimensional infrared (2D-IR) spectroscopy is uniquely suitable for monitoring femtosecond (fs) to picosecond (ps) water dynamics around static protein structures, its utility for probing enzyme active-site dynamics is limited due to the lack of site-specific 2D-IR probes. We demonstrate the genetic incorporation of a novel 2D-IR probe, m-azido-L-tyrosine (N3Y) in the active-site of DddK, an iron-dependent enzyme that catalyzes the conversion of dimethylsulfoniopropionate to dimethylsulphide. Our results show that both the oxidation of active-site iron to FeIII , and the addition of denaturation reagents, result in significant decrease in enzyme activity and active-site water motion confinement. As tyrosine residues play important roles, including as general acids and bases, and electron transfer agents in many key enzymes, the genetically encoded 2D-IR probe N3Y should be broadly applicable to investigate how the enzyme active-site motions at the fs-ps time scale direct reaction pathways to facilitating specific chemical reactions.


Assuntos
Azidas/metabolismo , Liases de Carbono-Enxofre/metabolismo , Compostos Férricos/metabolismo , Tirosina/análogos & derivados , Azidas/química , Liases de Carbono-Enxofre/química , Domínio Catalítico , Compostos Férricos/química , Estrutura Molecular , Espectrofotometria Infravermelho , Tirosina/química , Tirosina/metabolismo
9.
Angew Chem Int Ed Engl ; 60(21): 11858-11867, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-33533087

RESUMO

Correlated cell migration in fibrous extracellular matrix (ECM) is important in many biological processes. During migration, cells can remodel the ECM, leading to the formation of mesoscale structures such as fiber bundles. However, how such mesoscale structures regulate correlated single-cells migration remains to be elucidated. Here, using a quasi-3D in vitro model, we investigate how collagen fiber bundles are dynamically re-organized and guide cell migration. By combining laser ablation technique with 3D tracking and active-particle simulations, we definitively show that only the re-organized fiber bundles that carry significant tensile forces can guide strongly correlated cell migration, providing for the first time a direct experimental evidence supporting that matrix-transmitted long-range forces can regulate cell migration and self-organization. This force regulation mechanism can provide new insights for studies on cellular dynamics, fabrication or selection of biomedical materials in tissue repairing, and many other biomedical applications.


Assuntos
Movimento Celular/fisiologia , Colágeno/metabolismo , Matriz Extracelular/metabolismo , Mecanotransdução Celular/fisiologia , Actinas/metabolismo , Animais , Colágeno/química , Cães , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Células Madin Darby de Rim Canino , Miosinas/antagonistas & inibidores , Paxilina/metabolismo , Resistência à Tração
10.
Food Funct ; 12(3): 1232-1240, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33433545

RESUMO

The effects of potato and traditional staple foods (corn, wheat and rice) on physiology and gut microbiota were investigated by feeding ICR mice for 12 months. Compared with traditional staple foods, potato significantly improved the food and water intake and survival rate, and inhibited the swelling of viscera of mice, accompanied by a decreased white blood cell count and urine bilirubin content. Furthermore, potato significantly increased the relative abundance of Bacteroides and Faecalibacterium, which are short-chain fatty acid producing bacteria and play very important roles in the maintenance of human health. Meanwhile, potato significantly decreased the relative abundance of spoilage bacteria Pseudomonas and Thiobacillus. Analysis of putative metagenomes indicated that the potato diet upregulated the gene abundance of glycan biosynthesis and metabolism, digestive system and immune system. These findings indicated that potato has the potential to be an excellent substitute for traditional staple foods owing to its good physiological function and favorable gut microbiota modulation.


Assuntos
Microbioma Gastrointestinal/efeitos dos fármacos , Oryza , Solanum tuberosum , Triticum , Zea mays , Aminoacridinas , Ração Animal , Animais , Bactérias/classificação , Bactérias/efeitos dos fármacos , Peso Corporal , Dieta , Ingestão de Líquidos , Ingestão de Alimentos , Camundongos , Compostos de Mostarda Nitrogenada , Distribuição Aleatória
11.
J Sci Food Agric ; 101(7): 3049-3055, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33179311

RESUMO

BACKGROUND: The main objective of this study was to evaluate the safety and antihypertensive activity of rapeseed peptides and to investigate their potential synergy with captopril. RESULTS: The peptides were nontoxic with the maximum tolerated dose exceeding 25 g kg-1 BW d-1 for mice and they had angiotensin converting enzyme (ACE) inhibitory activity with IC50 value of 1.27 mg mL-1 . Rapeseed peptides did not have a synergistic effect with captopril on inhibiting ACE activity in simulated digestion tests in vitro. But in vivo they could synergistically augment the amplitude range of lowering blood pressure with captopril by approximately 9% and prolong the antihypertensive effect duration time by over 20% in antihypertension tests of spontaneously hypertensive rats. In addition, the inhibiting effect of rapeseed peptides on ACE activity was noticeable in some rat organs in vivo. Nevertheless, when compared to captopril group, the potential synergy of rapeseed peptides with captopril did not cause a further decrease in ACE activity in the organs but their synergy further improved levels of NO (12.7%) and endothelial nitric oxide synthase (74.1%) in rat serum. Further studies of some peptides identified from rapeseed peptides showed that some of the rapeseed peptides (Cys-Leu, Val-Ala-Pro) could markedly increase contents of NO and endothelial nitric oxide synthase. CONCLUSIONS: Rapeseed peptides have antihypertensive activity and they showed potential synergy with captopril in antihypertensive performance in vivo. The synergy was not from ACE inhibition but from other pathways, like improvement in endogenous vasodilator contents. © 2020 Society of Chemical Industry.


Assuntos
Anti-Hipertensivos/administração & dosagem , Brassica napus/química , Hipertensão/tratamento farmacológico , Peptídeos/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/metabolismo , Animais , Pressão Sanguínea/efeitos dos fármacos , Captopril/administração & dosagem , Sinergismo Farmacológico , Humanos , Hipertensão/enzimologia , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/metabolismo , Proteínas de Plantas/química , Ratos , Ratos Endogâmicos SHR
12.
Sci Total Environ ; 752: 142339, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33207521

RESUMO

Estuarine wetlands have experienced a variety of ecological and environmental problems caused by natural and anthropogenic factors. China has proposed a series of measures and made great efforts to control coastal degradation; however, decision makers still urgently need to know which measures to implement and how they will influence the estuarine environment and functions. This study used field observations, a hydrodynamic model, and statistical methods to investigate the effects of potential restoration scenarios on hydrodynamic conditions in the tidal-influenced estuarine wetland system, Liaodong Bay (China). Results reveal that the average total phosphorus, organic carbon, available phosphorus, pH, total nitrogen content, and moisture content in the soil and sediment environment were 0.04 ± 0.003%, 0.84 ± 0.25%, 16.3 ± 4.7 mg/kg, 8.3 ± 0.1, 0.07 ± 0.02%, and 44 ± 2%, respectively, exhibiting an overall trend of degradation. A series of restoration scenarios in regards to hydrodynamic regulation and tidal inputs were used to preserve the ecological value of the estuarine wetland. Model simulations indicate that the significant improvement of hydrodynamic fields (inundation depth and flow velocity) is more likely to occur when the tidal amplitudes reach around 2 m, while relatively weak responses can be observed when the tidal levels are lower than 1 m. Additionally, the construction of floodgates may play a key role in determining the tidal inputs and flowpaths across the wetland. The modifications in micro-topography of the wetland may play a complementary role in enhancing the connectivity condition via increased creek depth of 0.5 m and width up to around 20 m. This work represents a first attempt in exploring hydrodynamic effects of restoration scenarios for a tidal-dominated wetland. An improved understanding of the estuarine system also highlights that the design and implementation of wetland restoration projects should use more comprehensive measures to achieve long-term landscape management, connectivity planning, and ecological sustainability.

13.
Adv Mater ; 32(50): e2003164, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33164236

RESUMO

Exciton lifetime (τ) is crucial for the migration of excitons to donor/acceptor interfaces for subsequent charge separation in organic solar cells (OSCs); however, obvious prolongation of τ has rarely been achieved. Here, by introducing a solid additive 9-fluorenone-1-carboxylic acid (FCA) into the active layer, which comprises a nonfullerene acceptor, 3,9-bis(2-methylene-((3-(1,1-dicyanomethylene)-6/7-methyl)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene (IT-M), τ is substantially prolonged from 491 to 928 ps, together with obvious increases in fluorescence intensity and quantum yield. Time-resolved transient infrared spectra indicate the presence of an intermolecular vibrational coupling between the electronic excited state of IT-M and the electronic ground state of FCA, which is first observed here and which can suppress the internal conversion process. IT-M-based OSCs display an improved short-circuit current and fill factor after the addition of FCA. Thus, the power conversion efficiency is increased, particularly for devices with a large donor/acceptor ratio of 1:4, whose efficiency is increased by 56%. This study describes a novel method, which is also applicable to other nonfullerene acceptors, for further improving the performance of OSCs without affecting their morphology and light absorption properties.

14.
Adv Mater ; 32(40): e2004120, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32876964

RESUMO

A variety of infrared applications rely on semiconductor superlattices, including, notably, the realization of high-power, compact quantum cascade lasers. Requirements for atomically smooth interface and limited lattice matching options set high technical standards for fabricating applicable heterostructure devices. The semiconductor twinning superlattice (TSL) forms in a single compound with periodically spaced twin boundaries and sharp interface junctions and can be grown with convenient synthesis methods. Therefore, employing semiconductor TSL may facilitate the development of optoelectronic applications related to superlattice structures. Here, it is shown that InAs TSL nanowires generate inter-sub-band transition channels due to the band projection and the Bragg-like electron reflection. The findings reveal the physical mechanisms of inter-sub-band transitions in TSL structure and suggest that TSL structures are promising candidates for mid-infrared optoelectronic applications.

15.
Chemistry ; 26(58): 13295-13304, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32627241

RESUMO

Lithium-sulfur batteries, owing to the multi-electron participation in the redox reaction, possess enormous energy density, which has aroused much attention. Nevertheless, the detrimental shuttle effect, volume expansion, and electrical insulation of sulfur, have hindered their application. To improve the cyclability, a functional host, consisting of Co nanoparticles and N-doped hollow graphitized carbon (Co-NHGC) material, is elaborated, which has the advantages of: 1) the graphitized carbon material working as an electronic matrix to improve the utilization rate of sulfur; 2) the hollow structure relieving the stress change caused by volume expansion; 3) the rich active sites catalyze the electrochemical reaction of sulfur and entrap polysulfides. These advantages significantly improve the performance of the lithium-sulfur batteries. Accordingly, the S@Co-NHGC cathode exhibits excellent initial specific capacity, high coulombic efficiency, and excellent rate performance. This work utilizes a novel method of dopamine in situ etching of a metal-organic framework to synthetize the Co-NHGC host of sulfur, which will hopefully provide inspiration for other energy materials.

16.
Food Funct ; 11(5): 4403-4415, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32374308

RESUMO

In order to avoid the discomfort of digesting milk protein and make full use of the gastrointestinal digestive function, a milk macromolecular peptide was prepared with ACE inhibitory activity after gastrointestinal digestion as the index. Then, the antihypertensive activity of the milk macromolecular peptide in rats was evaluated. The results showed that the ACE inhibitory activity of hydrolysate after simulated gastrointestinal digestion was the highest in which the degree of hydrolysis was 17% and the ACE inhibitory activity reached 78.48%. The optimum enzymatic parameters were obtained with the protein concentration of 3.4%, enzymatic temperature of 55 °C, pH value of 7.0, and 7% enzyme amount using neutral protease. Under these conditions, the ACE inhibitory activity of hydrolysate after simulated gastrointestinal digestion was as high as 89.49%. Compared to traditional peptides, the ACE inhibitory activity of the macromolecular peptide increased after simulated gastrointestinal digestion. After 4 weeks of gavage tests of the milk macromolecular peptide, the blood pressure of rats with spontaneous hypertension dropped to below 140 mmHg, with a decrease of 60 mmHg. The antihypertensive effect of the milk macromolecular peptide was similar to that of captopril. The milk macromolecular peptide decreased the blood pressure of spontaneously hypertensive rats by inhibiting the ACE activity of the lung, kidney and arteries, and regulating the content of the signal factors of endothelin, NO, angiotensin II and renin in serum indicators. These results indicated that the macromolecular ACE inhibitory peptide with an antihypertensive effect could be prepared by the enzymatic hydrolysis of milk protein to realize the full utilization of protein resources.


Assuntos
Anti-Hipertensivos/farmacologia , Hipertensão , Leite , Peptídeos/farmacologia , Hidrolisados de Proteína/farmacologia , Inibidores da Enzima Conversora de Angiotensina/metabolismo , Animais , Anti-Hipertensivos/química , Pressão Sanguínea , Digestão , Modelos Animais de Doenças , Masculino , Peptídeos/química , Hidrolisados de Proteína/química , Ratos , Ratos Endogâmicos SHR
17.
Ultrason Sonochem ; 64: 104964, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32106063

RESUMO

The effects of two types (energy-divergent/gathered) of ultrasound pretreatment of protein on the Maillard reaction of protein-hydrolysate from grass carp (Ctenopharyngodon idella) were studied. The test and analysis of Fourier transform infrared spectroscopy, surface hydrophobicity and atomic force microscopy of protein, peptide concentration, molecular weight distribution and free amino acid content of protein-hydrolysate were performed to reveal the mechanism. Also, the sensory characteristics of Maillard reaction products were evaluated. Results showed that Maillard reaction products presented higher absorbance value at 294 and 420 nm after pretreated by two types of ultrasound compared to that of control. The grafting degree value of products pretreated by energy-divergent ultrasound increased by 13.87%. Both of these two types of ultrasound pretreatment showed higher (p < 0.05) value of grafting degree compared to that of positive control (thermal denaturation). The random coil content and surface hydrophobicity of protein improved significantly (p < 0.05), and the depth distribution of protein molecules narrowed down after pretreated by ultrasound, especially energy-divergent type ultrasound. The change of protein structure increased small molecular peptide/amino acid content in protein-hydrolysate, so that it promoted the Maillard reaction process of protein-hydrolysate and glucose. The mouthfulness and overall acceptance of Maillard reaction products increased after pretreated by two types of ultrasound. Results indicated that ultrasound, especially energy-divergent type ultrasound pretreatment of protein was an effective method to promote Maillard reaction evolution of protein-hydrolysate from grass carp protein and improved the flavor of Maillard reaction products.


Assuntos
Carpas , Proteínas de Peixes/química , Reação de Maillard , Ondas Ultrassônicas , Animais , Hidrólise , Peso Molecular , Estrutura Secundária de Proteína
18.
Ultrason Sonochem ; 64: 104846, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31987775

RESUMO

This study investigated effects of ultrasound on the contents of peptide and soluble protein, antioxidant activity, functionalities and structural characteristics of fermented soybean meal (FSBM) with Bacillus subtilis systematically. The results showed that there were significant effects of ultrasound treatments (frequency, treatment time and power density) on the contents of peptide and soluble protein (p < 0.05). Under the optimum ultrasound conditions (power density of 0.08 W/mL, frequency of 33 kHz and treatment time of 1 h) by single factor experiment, the contents of peptide and soluble protein increased by 31.27% and 18.79% compared to those of the control, respectively. Additionally, the in vitro antioxidant activity (•OH scavenging rate, Fe2+ chelating capacity and DPPH radical scavenging rate) and functional properties (emulsifying activity and emulsifying stability) of FSBM were found to be noticeably improved by ultrasound (p < 0.05). The fourier transform infrared (FTIR) spectroscopy revealed that ultrasound caused protein molecules to unfold with a decrease content of α-helix and ß-turn and an increase in the proportion of ß-sheet and random coil. Besides, atomic force microscope (AFM) results indicated that ultrasonication generally increased the surface roughness of protein and the protein sonicated with higher frequency (≥33 kHz) exhibited a greater height compared to lower frequency ultrasonication. Structure-activity relationship analysis illustrated that there was a good linear relationship between •OH scavenging rate and ß-sheet/ß-turn with Pearson's correlation coefficient r of -0.86/0.90. Collectively, the selection of ultrasonic parameters is essential for the preparation of functional protein and bioactive peptide by enhancing fermentation of agroindustrial by-products.


Assuntos
Bacillus subtilis/metabolismo , Fermentação , Proteínas de Plantas/química , Proteínas de Plantas/farmacologia , Sonicação , Soja/metabolismo , Ondas Ultrassônicas , Antioxidantes/química , Antioxidantes/farmacologia , Radical Hidroxila/química , Relação Estrutura-Atividade
19.
Sci Total Environ ; 710: 135499, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-31780175

RESUMO

Lakes and river-related floodplains are hydrologically complex and dynamic systems that exhibit frequent wetting and drying. Poyang Lake and its extremely productive wetland constitute the largest lake-floodplain system of the Yangtze River basin. This study aims to use a daily water balance model in combination with a physically based hydrodynamic model to investigate the overall hydrological regime of the lake-floodplain system. Water balance analysis shows that 79.0% and 12.2% of yearly inflows are from river discharges from the upstream gauged and downstream ungauged catchments, respectively. The direct precipitation contributes around 3.0% on the lake surface, while the balance of 1.2% is sourced from floodplain runoff (0.5%) and lake's backflow (0.7%). Around 86.9% of the total lake outflow is discharged into the Yangtze River, while 1.5% evaporates for the lake water surface. Net groundwater discharge (11.6%) has greater impacts on the water balance than the net groundwater recharge (4.6%). Water balance results highlight that the catchment rivers and the associated groundwater system are important parts of Poyang Lake. In general, the catchment rivers exhibit higher flashiness during the rising and flood periods than the other periods, and the flashiness in the lake downstream and floodplains is higher than in the lake upstream regions and the main lake, respectively, demonstrating spatiotemporal variability in the flood pulse in the lake-floodplain system. This study contributes to provide more detailed information regarding hydrological components and their relative effects to decision-makers for both Poyang Lake and other similar floodplains, given proposals to cope with the climate and human interventions and the accelerating pace of water resources and water safety management.

20.
Environ Microbiol ; 22(3): 1066-1088, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31600863

RESUMO

Soil microorganisms play a critical role in the biosphere, and the influence of cropland fertilization on the evolution of soil as a living entity is being actively documented. In this study, we used a shotgun metagenomics approach to globally expose the effects of 50-year N and P fertilization of wheat on soil microbial community structure and function, and their potential involvement in overall N cycling. Nitrogen (N) fertilization increased alpha diversity in archaea and fungi while reducing it in bacteria. Beta diversity of archaea, bacteria and fungi, as well as soil function, were also mainly driven by N fertilization. The abundance of archaea was negatively impacted by N fertilization while bacterial and fungal abundance was increased. The responses of N metabolism-related genes to fertilization differed in archaea, bacteria and fungi. All archaeal N metabolic processes were decreased by N fertilization, while denitrification, assimilatory nitrate reduction and organic-N metabolism were highly increased by N fertilization in bacteria. Nitrate assimilation was the main contribution of fungi to N cycling. Thaumarchaeota and Halobacteria in archaea; Actinobacteria, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Deltaproteobacteria in bacteria; and Sordariomycetes in fungi participated dominantly and widely in soil N metabolic processes.


Assuntos
Microbiota/efeitos dos fármacos , Nitrogênio/farmacologia , Fósforo/farmacologia , Microbiologia do Solo , Triticum/microbiologia , Archaea/efeitos dos fármacos , Archaea/fisiologia , Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Biodiversidade , Fertilizantes , Fungos/efeitos dos fármacos , Fungos/fisiologia , Estudos Longitudinais , Solo/química , Triticum/crescimento & desenvolvimento
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