RESUMO
Biofuel production from lignocellulose feedstocks is sustainable and environmentally friendly. However, the lignocellulosic pretreatment could produce fermentation inhibitors causing multiple stresses and low yield. Therefore, the engineering construction of highly resistant microorganisms is greatly significant. In this study, a composite functional chimeric cellulosome equipped with laccase, versatile peroxidase, and lytic polysaccharide monooxygenase was riveted on the surface of Saccharomyces cerevisiae to construct a novel yeast strain YI/LVP for synergistic lignin degradation and cellulosic ethanol production. The assembly of cellulosome was assayed by immunofluorescence microscopy and flow cytometry. During the whole process of fermentation, the maximum ethanol concentration and cellulose conversion of engineering strain YI/LVP reached 8.68 g/L and 83.41%, respectively. The results proved the availability of artificial chimeric cellulosome containing lignin-degradation enzymes for cellulosic ethanol production. The purpose of the study was to improve the inhibitor tolerance and fermentation performance of S. cerevisiae through the construction and optimization of a synergistic lignin-degrading enzyme system based on cellulosome.
Assuntos
Celulossomas , Etanol , Fermentação , Lignina , Saccharomyces cerevisiae , Etanol/metabolismo , Lignina/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Celulossomas/metabolismo , Celulossomas/genética , Celulose/metabolismo , Lacase/metabolismo , Lacase/genéticaRESUMO
Exploiting highly active and bifunctional catalysts for both hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR) is a prerequisite for the hydrogen acquisition. High-entropy materials have received widespread attention in catalysis, but the high-performance bifunctional electrodes are still lacking. Herein, a novel P-modified amorphous high-entropy CoFeNiCrMn compound is developed on nickel foam (NF) by one-step electrodeposition strategy. The achieved CoFeNiCrMnP/NF delivers remarkable HER and HzOR performance, where the overpotentials as low as 51 and 268 mV are realized at 100 mA cm-2 . The improved cell voltage of 91 mV is further demonstrated at 100 mA cm-2 by assessing CoFeNiCrMnP/NF in the constructed hydrazine-assisted water electrolyser, which is almost 1.54 V lower than the HER||OER system. Experimental results confirm the important role of each element in regulating the bifuncational performance of high-entropy catalysts. The main influencing elements seem to be Fe and Ni for HER, while the P-modification and Cr metal may contribute a lot for HzOR. These synergistic advantages help to lower the energy barriers and improve the reaction kinetics, resulting in the excellent bifunctional activity of the CoFeNiCrMnP/NF. The work offers a feasible strategy to develop self-supporting electrode with high-entropy materials for overall water splitting.
RESUMO
BACKGROUND: Atrial fibrillation (AF) is a prevalent and chronic cardiovascular disorder associated with various pathophysiological alterations, including atrial electrical and structural remodeling, disrupted calcium handling, autonomic nervous system dysfunction, aberrant energy metabolism, and immune dysregulation. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play a significant role in the pathogenesis of AF. OBJECTIVE: This discussion aims to elucidate the involvement of AF-related lncRNAs, with a specific focus on their role as miRNA sponges that modulate crucial signaling pathways, contributing to the progression of AF. We also address current limitations in AF-related lncRNA research and explore potential future directions in this field. Additionally, we summarize feasible strategies and promising delivery systems for targeting lncRNAs in AF therapy. CONCLUSION: In conclusion, targeting AF-related lncRNAs holds substantial promise for future investigations and represents a potential therapeutic avenue for managing AF.
RESUMO
Interfaces play an important role in enhancing the energy conversion performance of dye-sensitized solar cells (DSCs). The interface effects have been studied by many techniques, but most of the studies only focused on one part of a DSC, rather than on a complete solar cell. Hence, monitoring the interface evolution of a DSC is still very challenging. Here, inâ situ/operando resonance Raman (RR) spectroscopic analyses were carried out to monitor the dynamics of the photovoltaic conversion processes in a DSC. We observed the creation of new species (i.e., polyiodide and iodine aggregates) in the photosensitization process. We also obtained molecular-scale dynamic evidence that the bands from the C=C and C=N bonds of 2,2'-bipyridyl (bpy), the S=C=N bonds of the NCS ligand, and photochemical products undergo reasonably strong intensity and frequency changes, which clearly demonstrates that they are involved in charge separation. Furthermore, RR spectroscopy can also be used to quickly evaluate the performance of DSCs.
RESUMO
The effects of metformin on invertase activity and its inhibition on sucrose digestion were studied. The rapid unfolding kinetics of invertases, followed a two-state model with an inactive intermediate formation. The dynamic interaction between metformin and invertase caused the secondary structure of the enzyme to become less ß-sheet, more α-helix, and random coiling oriented, which weakened the binding force between enzyme and its substrate. Metformin acted as a chaotrope and disrupted the hydrogen bonds of water, which facilitated the unfolding of invertase. However, some sugar alcohols, which promoted the H-bond formation of water, could repair the secondary structure of metformin-denatured invertase and therefore regulate the enzyme activity. This research enriches our understanding of the mechanism of enzyme unfolding induced by guanidine compounds. Moreover, because metformin and sugar substitutes are of concern to diabetes, this research also provides useful information for understanding the activity of the digestive enzyme that coexists with metformin and sugar alcohols.
Assuntos
Metformina , beta-Frutofuranosidase , Metformina/química , Metformina/farmacologia , Cinética , beta-Frutofuranosidase/química , beta-Frutofuranosidase/metabolismo , Sacarose/química , Sacarose/metabolismo , Desdobramento de Proteína/efeitos dos fármacos , Ligação de Hidrogênio , Estrutura Secundária de Proteína , Digestão/efeitos dos fármacosRESUMO
Assembly ubiquitously occurs in nature and gives birth to numerous functional biomaterials and sophisticated organisms. In this work, chiral hydrogen-bonded organic-inorganic frameworks (HOIFs) are synthesized via biomimicking the self-assembly process from amino acids to proteins. Enjoying the homohelical configurations analogous to α-helix, the HOIFs exhibit remarkable chiroptical activity including the chiral fluorescence (glum = 1.7 × 10-3) that is untouched among the previously reported hydrogen-bonded frameworks. Benefitting from the dynamic feature of hydrogen bonding, HOIFs enable enantio-discrimination of chiral aliphatic substrates with imperceivable steric discrepancy based on fluorescent change. Moreover, the disassembled HOIFs after recognition applications are capable of being facilely regenerated and self-purified via aprotic solvent-induced reassembly, leading to at least three consecutive cycles without losing the enantioselectivity. The underlying mechanism of chirality bias is decoded by the experimental isothermal titration calorimetry together with theoretic simulation.
RESUMO
Background: Recent studies have shown a bidirectional relationship between atrial fibrillation (AF) and psychological depression. However, little is known about the prevalence of postprocedure depression (PPD) in patients with AF at the time of radiofrequency (RF) ablation. Objective: To describe the prevalence and identify risk factors for PPD. Methods: This was a prospective cohort study, including 428 AF patients who were willing to undergo the first catheter ablation in our hospital from 1st April to 30th December 2019. The primary outcome was PPD, which was determined by Hospital Anxiety and Depression Scale-Depression. Results: The prevalence of PPD was 16.8% (72/428) in our cohort, without difference between men (16.0%, 41/256) and women (18.0%, 31/172) (P = 0.586) but with a great difference among different age groups (P = 0.016). On the univariable binary logistic regression analysis, age, a history of coronary heart disease, Observer's Assessment of Alertness/Sedation (OAA/S) score when ablating at the specific position, and OAA/S score when pulling out the catheter sheath were associated with PPD. Subsequent multivariable logistic regression analysis indicated only age (OR 0.96, 95% CI: 0.94-0.99, P < 0.01) and OAA/S score when ablating at the specific position (OR 0.58, 95% CI: 0.39-0.88, P = 0.01) were independently associated with PPD. Conclusion: PPD is common in patients with AF after RF ablation. Younger age and lower OAA/S score when ablating at the specific position are its most significant risk factors. Intensive management of sedation may be of great importance for reducing PPD. This trial is registered with the Chinese Clinical Trial Registry (ChiCTR2200057810).
RESUMO
Developing high-performance and low-cost self-supporting electrodes as pH-universal electrocatalysts for the hydrogen-evolution reaction (HER) and realizing high-quality hydrogen production at a high current density are highly desirable, but are hugely challenging. We created a self-supporting electrode with a coupled hierarchical heterostructure by simple electrodeposition followed by sulfurization. It comprised oxygen-deficient molybdenum oxide (MoO3-x) and cobalt phosphide (CoP) on nickel foam (NF), which represented a highly active pH-universal electrocatalyst for the HER at a high current density. Benefiting from a plethora of catalytic active sites, improved interfacial charge transfer, and strong electronic interaction, this type of MoO3-x@CoP/NF electrode delivered a superior catalytic performance. Overpotentials of only 100 mV, 135 mV, and 400 mV were needed to realize a high current density of 1 A cm-2 in alkaline, acid and neutral media, respectively, which were superior to those of most other well-developed materials based on non-noble metals. Our experimental work demonstrates the synergistic advantages of a MoO3-x@CoP heterostructure for improving the intrinsic catalytic performance but also paves a new path for the rational design of advanced electrodes for hydrogen generation in a wide range of pH conditions.
RESUMO
The subjective measurement of the dynamic perception of sweetness is a problem in food science. Herein, the rapid interactions of sugars and sugar alcohols with sweet taste receptors on living cells on a millisecond timescale were studied via stopped-flow fluorescence spectroscopy. According to the rapid-kinetic parameters, sweeteners were divided into two groups. Sweeteners in group I disrupted the hydrogen bond network structure of water, and the apparent rate constant (kobs) was in the range of 0.45-0.6 s-1. Sweeteners in group II promoted the hydrogen bond formation of water, and the kobs was mostly in the range of 0.6-0.75 s-1. For most sweeteners, the kobs of cell responses was negatively correlated with the apparent specific volume of sweeteners. The differences in the cellular responses may be attributed to the disturbance in the water structure. Experimental results showed that the kinetic parameters of sweet cell responses reflected the dynamic perception of sweetness. Rapid kinetics, solution thermodynamic analysis, and water structure analysis enriched the physicochemical study of the sweetness mechanism and can be used to objectively evaluate the dynamic perception of sweetness.
RESUMO
BACKGROUND: Atrial fibrillation (AF) has been accepted as an inflammatory atrial myopathy. Interleukin 6 (IL-6)-dependent inflammatory signaling pathways take context-dependent effects on cardiovascular diseases. IL-6 trans-signaling is predominantly pro-inflammatory. However, its effect on AF is unclear. OBJECTIVE: The purpose of this study was to investigate the role of IL-6 trans-signaling in AF. METHODS: Circulating levels of IL-6, soluble IL-6 receptor, and soluble glycoprotein 130 (sgp130) in patients with AF and controls were measured to estimate the activation of IL-6 trans-signaling. A mouse model of AF was established by transverse aortic constriction surgery. Sgp130Fc administration was used for the selective blockade of IL-6 trans-signaling. Studies were conducted to evaluate the effects and underlying mechanisms of sgp130Fc on AF inducibility and atrial conduction abnormalities and structural remodeling. RESULTS: In patients, the elevation of IL-6 trans-signaling level was positively associated with AF occurrence. IL-6 trans-signaling activation was recapitulated in the mouse model of AF. In transverse aortic constriction-challenged mice, the selective blockade of IL-6 trans-signaling with sgp130Fc attenuated AF inducibility, which was attributable to the amelioration of slow conduction and conduction heterogeneity induced by atrial dilation, fibrosis, and reduction in connexin 40 and redistribution of connexin 43. Sgp130Fc administration also reduced immune cell infiltration and oxidative stress in the mouse atrium and abrogated IL-6 trans-signaling activation-mediated connexin dysregulation and reactive oxygen species production in atrial myocytes. CONCLUSION: IL-6 trans-signaling activation contributes to AF development, and its selective blockade may promise a novel therapeutic strategy.
Assuntos
Fibrilação Atrial , Remodelamento Atrial , Humanos , Camundongos , Animais , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/etiologia , Fibrilação Atrial/metabolismo , Interleucina-6/metabolismo , Transdução de Sinais , Átrios do Coração , Miócitos Cardíacos/metabolismoRESUMO
As a local medicine and food, wampee fruit, with abundant bioactive compounds, is loved by local residents in Southern China. Titratable acid (TA), total sugar (TS), and total phenolic and flavonoid contents were detected, and phytochemical profiles and cellular antioxidant activities were analyzed by the HPLC and CAA (cellular antioxidant activity) assay in five sweet wampee varieties and five sour wampee varieties. Results showed that the average TS/TA ratio of sweet wampee varieties was 29 times higher than sour wampee varieties, while TA content was 19 times lower than sour wampee varieties. There were much lower levels of total phenolics, flavonoids, and antioxidant activities in sweet wampee varieties than those in sour wampee varieties. Eight phytochemicals were detected in sour wampee varieties, including syringin, rutin, benzoic acid, 2-methoxycinnamic acid, kaempferol, hesperetin, nobiletin, and tangeretin, while just four of them were detected in sweet wampee varieties. Syringin was the only one that was detected in all the sour wampee varieties and was not detected in all sweet wampee varieties. Correlation analysis showed significant positive correlations between TA with phenolics, flavonoids, and total and cellular (PBS wash) antioxidant activities, while there were significant negative correlations between TS/TA with phenolic and cellular (no PBS wash) antioxidant activities. This suggested that the content of titratable acid in wampee fruit might have some relationship with the contents of phenolics and flavonoids. Sour wampee varieties should be paid much attention by breeders for their high phytochemical contents and antioxidant activities for cultivating germplasms with high health care efficacy.
RESUMO
α-Amylase plays an important role in food processing and in-vivo digestion. Many biological functions of α-amylase are affected by unfolding. The pre-steady-state rapid unfolding kinetics of α-amylase remains unknown. In this study, the rapid unfolding kinetics of porcine pancreatic α-amylase (PPA) with guanidine hydrochloride (GdmHCl) were investigated by stopped-flow spectroscopy. Structural characterization of PPA by fluorescence spectroscopy, and molecular dynamics simulation showed that the unfolding process of PPA might start from the internal active center, where the ß-sheet structure was destroyed, followed by the exposure of hydrophobic amino acid residues. Further research revealed that GdmHCl denaturized PPA not by complexing with PPA. The surrounding H-bond network of water was changed by GdmHCl. This research improves our understanding of the unfolding kinetics of the PPA on the microsecond scale. It also provides the evidence experimentally of the surrounding water contribution to protein denaturization.
Assuntos
alfa-Amilases Pancreáticas , alfa-Amilases , Animais , Guanidina , Cinética , Pâncreas/metabolismo , Desnaturação Proteica , Espectrometria de Fluorescência , Suínos , alfa-Amilases/metabolismoRESUMO
In this work, the rapid unfolding kinetics of pancreas α-amylase (PPA) induced by l-arginine and the interaction mechanism were investigated. The unfolding followed a first-level reaction kinetics equation, without intermediates. l-arginine interacted with PPA though diffusion-controlled process rather than complexion. The interaction between l-arginine and PPA resulted in a pronounced decrease in ß-sheet and a significant increase in random coil, and thereby the enzyme activity decreased. However, the unfolding of PPA could be compensated and the second structure change could be recovered to some extent by the macromolecular crowded medium of Pluronics. Further insight into the mechanism disclosed that the broken H-bond network of water may contribute to PPA unfolding. This work provides a new perspective on the interaction of l-arginine with digestive enzyme. The unfolding mechanism of enzymes by may help to understand the effects of other structurally similar drugs, which is of concern in food-drug interactions.
Assuntos
alfa-Amilases Pancreáticas , alfa-Amilases , Amilases , Arginina , Cinética , alfa-Amilases/metabolismoRESUMO
Starch is an ideal wall material for controlled release in oral delivery systems due to its non-allergic properties, availability, and cheap price. However, because of its poor mechanical behavior and high water permeability, it is necessary to modify the amphiphilic nature of starch. Surfactants are essential components to emulsify the lyophobic food ingredients. However, the interaction of starch with emulsifiers and how they affect the pasting behavior and digestion of starch are not well understood. In this paper, surfactants, such as non-ionic Tween (TW) and ionic sodium fatty acid (NaFA), with varying hydrophobic carbon chain lengths, were selected as model amphiphiles to investigate the structural, pasting, rheological properties and in vitro digestibility of regular and frozen starch samples. The results showed that, in most cases, the addition of TW reduced the viscosity of starch. However, saturated medium-chain NaFA increased the starch viscosity and rheological modulus greatly. Both surfactants inhibited starch digestion. This paper presents a comparative investigation on the effect of ionic and non-ionic surfactant on the structure and properties of corn starch, and therefore the information is useful for structural-based formulation with starch for developing colloidal delivery systems. It is also helpful for developing functional food with controllable digestion properties.
RESUMO
Phosphorus (P) recovery from sewage sludge is one of the promising substitutes to the phosphate ores to alleviate the shortage of P supply in the future. In this study, how hydrothermal carbonization (HTC) temperature functioned in the migration and transformation of P from sewage sludge during HTC process was clarified. The enhancement effect of Ca-based additive on the transformation of P to hydroxyapatite via HTC was systematically studied. Additionally, leaching characteristics of P in the hydrochars with Ca-based additive were analyzed to assess their P-bioavailability. Results indicated that favoring by increased pH in the process water, HTC temperature played a significant role in the migration and transformation of P during HTC. Therefore, higher HTC temperature was beneficial for P enrichment and transformation to apatite phosphorus in the hydrochars. Both alkaline environment and existence of sufficient calcium ions were essential for enhanced formation of apatite phosphorus during HTC. Adding CaO could stimulate almost complete transformation of non-apatite inorganic phosphorus to apatite phosphorus such as hydroxyapatite, causing a maximum increase of apatite phosphorus by 252%. Concurrently, P-bioavailability by 2% (w/w) formic acid extraction of the hydrochars increased by 233% at CaO = 4%. These findings were confirmed by XRD analyses. Ca-associated apatite phosphorus such as Ca5(PO4)3OH and Ca2P2O7 â 2H2O, was detected in the hydrochars. With the assistance of thermochemical calculation, transformation pathways of P after CaO addition have been proposed, which coincided with our experimental results well. The stable P-containing minerals of hydroxyapatite (Ca5(PO4)3OH) was calculated at equilibrium state.
RESUMO
Flaxseed (Linum usitatissimum L.) is a rich source of nutritive and bioactive compounds. The research evaluated the disparity in phytochemical profiles along with total and cellular antioxidant activities between oil and fiber flaxseeds. There were significant differences in total phenolics, total flavonoids and antioxidant activities among the six cultivars of fiber and oil flaxseed, respectively. Four phytochemical compounds including caffeic acid, p-coumaric acid and ferulic acid, and secoisolariciresinol diglucoside (SDG) were identified and quantified in the cultivars of oil and fiber flaxseed by HPLC analysis. Notably, the average of total phenolic and flavonoid contents, along with total antioxidant activities between fiber and oil flaxseeds were not different significantly; even the cellular antioxidant activity of fiber flaxseed was superior to oil flaxseed. These results suggest that fiber flaxseeds would be valuable candidates as functional products and dietary supplements production owing to the higher bioactive values as well as oil flaxseeds.
Assuntos
Fibras na Dieta/análise , Linho/química , Óleo de Semente do Linho/química , Compostos Fitoquímicos/análise , Sementes/química , Butileno Glicóis/análise , Cromatografia Líquida de Alta Pressão/métodos , Ácidos Cumáricos/análise , Flavonoides/análise , Glucosídeos/análise , Fenóis/análise , PropionatosRESUMO
OBJECTIVE: To conduct a systematic evaluation of the efficacy of lansoprazole and omeprazole for the treatment of Helicobacter pylori-associated duodenal ulcer. METHODS: Online databases, including CHKD, VIP, China Info, the National Digital Library of China, Google Scholar, PubMed, Lippincott Williams & Wilkins, and Wiley Online Library were searched for related studies. The quality of the studies was evaluated in accordance with the Cochrane Handbook for Systematic Reviews of Interventions, and relevant information was extracted from them. The studies were subjected to meta-analysis using RevMan5.3 software, and qualitative analysis was performed for studies, in which the data could not be merged. RESULTS: A total of nine randomized controlled trials (RCTs) were included, all of which presented the possibility of bias. Meta-analysis showed no significant differences between patients treated with lansoprazole combinations and omeprazole combinations in terms of DU healing rate (RR = 1.04, 95% CI = 0.99~1.09, P = 0.93). There were significant differences between those treated by lansoprazole combination and omeprazole combination in terms of HP eradication rate (RR = 1.09, 95% CI = 1.01~1.18, P = 0.04), and there was no serious adverse reaction during the treatment process for both lansoprazole and omeprazole. CONCLUSION: Lansoprazole and omeprazole exhibit similar efficacy in the treatment of Helicobacter pylori associated duodenal ulcers.