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1.
Am J Hum Genet ; 108(8): 1478-1487, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34197731

RESUMO

Idiopathic achalasia (IA) is a severe motility disorder characterized by neuronal degeneration in the myenteric plexus, but the etiology remains largely unknown. We performed whole-exome sequencing (WES) in 100 IA-affected individuals and 313 non-IA control subjects and validated the results in 230 IA-affected individuals and 1,760 non-IA control subjects. Common missense variants rs1705003 (CUTA, GenBank: NC_000006.11:g.33385953A>G) and rs1126511 (HLA-DPB1, GenBank: NC_000006.11:g.33048466G>T) at 6p21.32 were reproducibly associated with increased risk of IA (rs1126511: OR = 1.83, p = 2.34 × 10-9; rs1705003: OR = 2.37, p = 3.21 × 10-7), meeting exome-wide significance. Both variants can affect the expression of their target genes at the transcript level. An array-based association analysis in 280 affected individuals and 1,121 control subjects determined the same signal at 6p21.32. Further conditional analyses supported that the two missense variants identified in WES-based association study were potential causal variants of IA. For rare variants, the top genes identified by gene-based analysis were significantly enriched in nerve and muscle phenotypic genes in the mouse. Moreover, the functional rare variants in these genes tended to cooccur in IA-affected individuals. In an independent cohort, we successfully validated three rare variants (CREB5, GenBank: NC_000007.13:g.28848865G>T; ESYT3, GenBank: NC_000003.11:g.138183253C>T; and LPIN1, GenBank: NC_000002.11:g.11925128A>G) which heightens the risk of developing IA. Our study identified and validated two common variants and three rare variants associated with IA in immunologic and neurological genes, providing new insight into the etiology of IA.


Assuntos
Proteína A de Ligação a Elemento de Resposta do AMP Cíclico/genética , Acalasia Esofágica/patologia , Sequenciamento do Exoma/métodos , Exoma , Predisposição Genética para Doença , Variação Genética , Fosfatidato Fosfatase/genética , Sinaptotagminas/genética , Estudos de Casos e Controles , Acalasia Esofágica/genética , Testes Genéticos , Humanos , Fenótipo
2.
J Environ Manage ; 358: 120936, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38652989

RESUMO

Manure replacing synthetic fertilizer is a viable practice to ensure crop yield and increase soil organic carbon (SOC), but its impact on greenhouse gas (GHG) emissions is inconsistent, thus remains its effect on CF unclear. In this study, a 7-year field experiment was conducted to assess the impact of replacing synthetic fertilizer with manure on crop productivity, SOC sequestration, GHG emissions and crop CF under winter wheat-summer maize cropping system. Five treatments were involved: synthetic nitrogen, phosphorus, and potassium fertilizer (NPK) and 25%, 50%, 75%, and 100% of manure replacing synthetic N (25%M, 50%M, 75%M, and 100%M). Compared with NPK treatment, 25%M and 50%M treatments maintained annual yield (winter wheat plus summer maize) and sustainable yield index (SYI), but 75%M and 100%M treatments significantly decreased annual yield, and 100%M treatment also significantly reduced annual SYI. The SOC content exhibited a significant increasing trend over years in all treatments. After 7 years, SOC storage in manure treatments increased by 3.06-11.82 Mg ha-1 relative to NPK treatment. Manure treatments reduced annual GHG emissions by 14%-60% over NPK treatment. The CF of the cropping system ranged from 0.16 to 0.39 kg CO2 eq kg-1 of grain without considering SOC sequestration, in which the CF of manure treatments lowered by 18%-58% relative to NPK treatment. When SOC sequestration was involved in, the CF varied from -0.39 to 0.37 kg CO2 eq kg-1 of grain, manure treatments significantly reduced the CF by 22%-208% over NPK treatment. It was concluded that replacing 50% of synthetic fertilizer with manure was a sound option for achieving high crop yield and SYI but low CF under the tested cropping system.


Assuntos
Pegada de Carbono , Fertilizantes , Esterco , Solo , Triticum , Zea mays , Zea mays/crescimento & desenvolvimento , Triticum/crescimento & desenvolvimento , Solo/química , Carbono , Estações do Ano , Nitrogênio , Produtos Agrícolas/crescimento & desenvolvimento , Agricultura/métodos , Gases de Efeito Estufa
3.
Bioprocess Biosyst Eng ; 45(10): 1673-1682, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35964262

RESUMO

Polymalic acid (PMA) is a water-soluble polyester produced by Aureobasidium pullulans. In this study, the physiological response of A. pullulans after the addition of vegetable oils was investigated. Soybean oil (SBO) is pivotal for shortening fermentation time and achieving high PMA titer. With the addition of 1% (w/v) SBO, the titer and productivity of PMA was, respectively, increased by 34.2% and 80%. SBO acted as a chemical stimulatory agent rather than a carbon source, the enhancement on PMA production was attributed to the component of fatty acid. SBO induced the dimorphism (yeast-like cells and mycelia) of A. pullulans, in vitro enzyme activities indicated that the TCA oxidative branch for malic acid synthesis might be strengthened, which could generate more ATP for PMA synthesis, and the assay of intracellular energy supply validated this deduction. This study provided a new sight for recognizing the regulatory behavior of SBO in A. pullulans.


Assuntos
Ascomicetos , Óleo de Soja , Trifosfato de Adenosina , Aureobasidium , Carbono/farmacologia , Ácidos Graxos , Fermentação , Malatos/farmacologia , Poliésteres , Polímeros , Óleo de Soja/farmacologia , Água
4.
Int J Mol Sci ; 22(19)2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34639118

RESUMO

An α-galactosidase-producing strain named Anoxybacillus vitaminiphilus WMF1, which catalyzed the reverse hydrolysis of d-galactose and glycerol to produce isofloridoside, was isolated from soil. The α-galactosidase (galV) gene was cloned and expressed in Escherichia coli. The galV was classified into the GH36 family with a molecular mass of 80 kDa. The optimum pH and temperature of galV was pH 7.5 and 60 °C, respectively, and it was highly stable at alkaline pH (6.0-9.0) and temperature below 65 °C. The specificity for p-nitrophenyl α-d-galactopyranoside was 70 U/mg, much higher than that for raffinose and stachyose. Among the metals and reagents tested, galV showed tolerance in the presence of various organic solvents. The kinetic parameters of the enzyme towards p-nitrophenyl α-d-galactopyranoside were obtained as Km (0.12 mM), Vmax (1.10 × 10-3 mM s-1), and Kcat/Km (763.92 mM-1 s-1). During the reaction of reverse hydrolysis, the enzyme exhibited high specificity towards the glycosyl donor galactose and acceptors glycerol, ethanol and ethylene glycol. Finally, the isofloridoside was synthesized using galactose as the donor and glycerol as the acceptor with a 26.6% conversion rate of galactose. This study indicated that galV might provide a potential enzyme source in producing isofloridoside because of its high thermal stability and activity.


Assuntos
Anoxybacillus/enzimologia , Galactosídeos/biossíntese , Temperatura Alta , alfa-Galactosidase/metabolismo , Sequência de Aminoácidos , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Peso Molecular , Homologia de Sequência , Especificidade por Substrato , alfa-Galactosidase/química
5.
J Sci Food Agric ; 101(14): 5956-5962, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33838057

RESUMO

BACKGROUND: Plastic film mulch is widely used to improve crop yield and water use efficiency (WUE, yield per unit evapotranspiration) in semi-arid regions. It is commonly applied as partial-film mulch (PM: at least 50% soil cover) or full-film mulch (FM: complete soil cover). The PM has lower economic and environmental cost; hence it would be a superior technology provided it delivers similar gains in yield and WUE in relation to FM. RESULTS: To solve contradictory results from individual studies, we compared FM and PM in a meta-analysis of 100 studies with 1881 comparisons (685 for wheat; 1196 for maize). Compared with bare ground, FM and PM both increased yield of wheat (20-26%) and maize (37-52%), and WUE of wheat (16-20%) and maize (38-48%), with statistically undistinguishable differences between PM and FM. The increases in crop yield and WUE were stronger at elevation > 1000 m, with annual precipitation<400 mm, and on loess soil, especially for maize. CONCLUSIONS: We concluded that partial-film mulch could replace full-film mulch to return similar yield and WUE improvement, with reduced cost and environmental pollution. © 2021 Society of Chemical Industry.


Assuntos
Agricultura/métodos , Plásticos/economia , Triticum/crescimento & desenvolvimento , Água/metabolismo , Zea mays/crescimento & desenvolvimento , Agricultura/economia , Poluição Ambiental/prevenção & controle , Solo/química , Triticum/metabolismo , Água/análise , Zea mays/metabolismo
6.
Angew Chem Int Ed Engl ; 59(13): 5202-5210, 2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-31943677

RESUMO

Freshwater scarcity is a global challenge threatening human survival, especially for people living in arid regions. Sorption-based atmospheric water harvesting (AWH) is an appealing way to solve this problem. However, the state-of-the-art AWH technologies have poor water harvesting performance in arid climates owing to the low water sorption capacity of common sorbents under low humidity conditions. We report a high-performance composite sorbent for efficient water harvesting from arid air by confining hygroscopic salt in a metal-organic framework matrix (LiCl@MIL-101(Cr)). The composite sorbent shows 0.77 g g-1 water sorption capacity at 1.2 kPa vapor pressure (30 % relative humidity at 30 °C) by integrating the multi-step sorption processes of salt chemisorption, deliquescence, and solution absorption. A highly efficient AWH prototype is demonstrated with LiCl@MIL-101(Cr) that can enable the harvesting of 0.45-0.7 kg water per kilogram of material under laboratory and outdoor ambient conditions powered by natural sunlight without optical concentration and additional energy input.

7.
BMC Biotechnol ; 17(1): 20, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28231788

RESUMO

BACKGROUND: poly(L-malic acid) (PMA) is a water-soluble polyester with many attractive properties in medicine and food industries, but the high cost of PMA fermentation has restricted its further application for large-scale production. To overcome this problem, PMA production from Jerusalem artichoke tubers was successfully performed. Additionally, a valuable exopolysaccharide, pullulan, was co-produced with PMA by Aureobasidum pullulans HA-4D. RESULTS: The Jerusalem artichoke medium for PMA and pullulan co-production contained only 100 g/L hydrolysate sugar, 30 g/L CaCO3 and 1 g/L NaNO3. Compared with the glucose medium, the Jerusalem artichoke medium resulted in a higher PMA concentration (114.4 g/L) and a lower pullulan concentration (14.3 g/L) in a 5 L bioreactor. Meanwhile, the activity of pyruvate carboxylase and malate dehydrogenas was significantly increased, while the activity of α-phosphoglucose mutase, UDP-glucose pyrophosphorylase and glucosyltransferase was not affected. To assay the economic-feasibility, large-scale production in a 1 t fermentor was performed, yielding 117.5 g/L PMA and 15.2 g/L pullulan. CONCLUSIONS: In this study, an economical co-production system for PMA and pullulan from Jerusalem artichoke was developed. The medium for PMA and pullulan co-production was significantly simplified when Jerusalem artichoke tubers were used. With the simplified medium, PMA production was obviously stimulated, which would be associated with the improved activity of pyruvate carboxylase and malate dehydrogenas.


Assuntos
Ascomicetos/metabolismo , Glucanos/economia , Glucanos/metabolismo , Helianthus/metabolismo , Malatos/economia , Malatos/metabolismo , Polímeros/economia , Polímeros/metabolismo , Ascomicetos/genética , Técnicas de Cultura Celular por Lotes/métodos , Engenharia Genética/economia , Engenharia Genética/métodos , Glucanos/genética , Glucanos/isolamento & purificação , Helianthus/genética , Malatos/isolamento & purificação , Tubérculos/genética , Tubérculos/metabolismo , Polímeros/isolamento & purificação
8.
Prep Biochem Biotechnol ; 46(8): 798-802, 2016 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-26829650

RESUMO

Poly(L-malic acid) (PMA) is a natural polyester with many attractive properties for biomedical application. However, the cost of PMA production is high when glucose is used as a carbon source. To solve this problem, cane molasses as a low-cost feedstock was applied for the production of PMA. Six pretreatment methods were applied to cane molasses before fermentation. Pretreatment with combined tricalcium phosphate, potassium ferrocyanide, and sulfuric acid (TPFSA) removed significant amounts of metal ions from cane molasses. The PMA concentration increased from 5.4 g/L (untreated molasses) to 36.9 g/L (TPFSA-pretreated molasses) after fermentation in shake flasks. A fed-batch fermentation strategy was then developed. In this method, TPFSA-pretreated cane molasses solution was continuously fed into the fermentor to maintain the total sugar concentration at 20 g/L. This technique generated approximately 95.4 g/L PMA with a productivity of 0.57 g/L/hr. The present study indicated that fed-batch fermentation using pretreated cane molasses is a feasible technique for producing high amounts of PMA.


Assuntos
Ascomicetos/metabolismo , Fermentação , Microbiologia Industrial/métodos , Malatos/metabolismo , Polímeros/metabolismo , Saccharum/metabolismo
9.
Sci Bull (Beijing) ; 69(5): 671-687, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38105159

RESUMO

Establishing alternative methods for freshwater production is imperative to effectively alleviate global water scarcity, particularly in land-locked arid regions. In this context, extracting water from the ubiquitous atmospheric moisture is an ingenious strategy for decentralized freshwater production. Sorption-based atmospheric water harvesting (SAWH) shows strong potential for supplying liquid water in a portable and sustainable way even in desert environments. Herein, the latest progress in SAWH technology in terms of materials, devices, and systems is reviewed. Recent advances in sorbent materials with improved water uptake capacity and accelerated sorption-desorption kinetics, including physical sorbents, polymeric hydrogels, composite sorbents, and ionic solutions, are discussed. The thermal designs of SAWH devices for improving energy utilization efficiency, heat transfer, and mass transport are evaluated, and the development of representative SAWH prototypes is clarified in a chronological order. Thereafter, state-of-the-art operation patterns of SAWH systems, incorporating intermittent, daytime continuous and 24-hour continuous patterns, are examined. Furthermore, current challenges and future research goals of this cutting-edge field are outlined. This review highlights the irreplaceable role of heat and mass transfer enhancement and facile structural improvement for constructing high-yield water harvesters.

10.
Bioresour Technol ; 394: 130218, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38109976

RESUMO

Production of 2,6-dihydroxybenzoic acid (2,6-DHBA) via enzymatic carboxylation of resorcinol by decarboxylases is of great promising but shows depressed equilibrium conversion. In this study, 2,3-dihydroxybenzoic acid decarboxylase from Aspergillus oryzae (2,3-DHBD_Ao) pushing the conversion towards carboxylation for efficient 2,6-DHBA biosynthesis was achieved. Meanwhile, a novel amino-modified and lignin-doped cellulose nanocrystal aerogel (A-LCNCA) with high specific surface area and prominent CO2 capture was prepared for 2,3-DHBD_Ao immobilization. 2,3-DHBD_Ao@A-LCNC contributed a further enhanced conversion of carboxylation with the maximal conversion of 76.2 %, which was correlated to both the activity of 2,3-DHBD_Ao and the high CO2 loading capacity of A-LCNCA. Moreover, 2,3-DHBD_Ao@A-LCNC exhibited superior performances in a wider range of temperature and higher concentrations of substrate, with a prolonged storage period longer than 30 days. After seven cycles reuse, 2,3-DHBD_Ao@A-LCNCA could retain 85.3 % of its original activity. These results suggest a considerable potential of 2,3-DHBD_Ao@A-LCNCA in the selective biosynthesis of 2,6-DHBA.


Assuntos
Carboxiliases , Hidroxibenzoatos , Nanopartículas , Lignina , Dióxido de Carbono , Celulose
11.
Int J Pediatr ; 2024: 9271324, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38957711

RESUMO

Objective: To summarize the clinical characteristics and treatment experiences of patients with plastic bronchitis (PB). Methods: All patients who were diagnosed with PB by bronchoscopic removal of tree-like casts at a single institution from January 2012 to May 2022 were retrospectively reviewed. Demographic and clinical data were retrieved from electronic patient records. Results: A total of 55 patients, with a median age of 5.3 years, were eligible for the study. Nineteen cases had underlying diseases, among which asthma was the most common. The median course of the disease before admission was 11 days. Clinical symptoms were characterized by cough and fever, while moist rales (78.2%) and dyspnea (61.8%) were the most common signs. The most common laboratory finding was elevated C-reactive protein (58.2%). Patchy opacity was the most frequent radiographic finding (81.2%), followed by consolidation (60.0%) and pleural effusion (43.6%). Respiratory pathogens were detected in 41 cases, and M. pneumoniae was the most common one (41.8%), followed by adenovirus (20.0%) and influenza B virus (10.9%). The casts were removed by alveolar lavage, combined with ambroxol immersion (63.6%) and forceps (30.9%). Patients received an average of 2.3 bronchoscopies, and the median time for the first procedure was 3 days after admission. Antibiotics were given to all patients, methylprednisolone to 33 (60.0%), and gamma globulin to 25 (45.5%). A total of 53 cases were improved with an overall mortality rate of 3.6%. Conclusions: PB in children is characterized by airway obstruction, mostly caused by respiratory infections, and timely removal of the cast by bronchoscopy is the most effective treatment.

12.
Int J Biol Macromol ; 276(Pt 1): 133735, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38986980

RESUMO

Urinary tract infection caused by Klebsiella, Proteus and Streptococcus is a urease dependent process, hence treatment of these infections by antibacterial compounds lies in inhibition of their virulence factors. The crude methanolic extracts derived from sumac fruit, pomegranate peel and Indian almond leaves were separated into anthocyanin and non-anthocyanin fractions using solid phase cartridges. The inhibitory effect of these fractions was determined on the growth of urease producing species and jack bean urease activity. Known compounds in the fractions were also docked with ureases of different biological origins viz. K. pneumoniae (PDB ID: 8HCN), K. aerogenes (PDB ID: 2KAU), Helicobacter pylori (PDB ID:8HC1)and Canavalia ensiformis (jack bean) (PDB ID: 3LA4) to determine their binding affinities and interaction with the enzyme. All the fractions showed significant inhibition growth for P. mirabilis, S. epidermidis and K.pneumoniae. Among the samples, sumac showed greatest inhibition against all (MIC 6-25 mg.mL-1) while among the fractions, anthocyanin was found to be most active (MIC 6-12 mg/mL). Likewise, all fractions inhibited urease with lowest ICs50 shown by sumac fractions (21-116 µg.mL-1). Out of 39 compounds docked, 27 showed interaction with movable flaps and/or active site of ureases which explains their mode of inhibition.

13.
IEEE Trans Med Imaging ; PP2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38656865

RESUMO

Functional magnetic resonance imaging (fMRI) is a commonly used technique to measure neural activation. Its application has been particularly important in identifying underlying neurodegenerative conditions such as Parkinson's, Alzheimer's, and Autism. Recent analysis of fMRI data models the brain as a graph and extracts features by graph neural networks (GNNs). However, the unique characteristics of fMRI data require a special design of GNN. Tailoring GNN to generate effective and domain-explainable features remains challenging. In this paper, we propose a contrastive dual-attention block and a differentiable graph pooling method called ContrastPool to better utilize GNN for brain networks, meeting fMRI-specific requirements. We apply our method to 5 resting-state fMRI brain network datasets of 3 diseases and demonstrate its superiority over state-of-the-art baselines. Our case study confirms that the patterns extracted by our method match the domain knowledge in neuroscience literature, and disclose direct and interesting insights. Our contributions underscore the potential of ContrastPool for advancing the understanding of brain networks and neurodegenerative conditions. The source code is available at https://github.com/AngusMonroe/ContrastPool.

14.
Phytomedicine ; 129: 155570, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38579645

RESUMO

BACKGROUND: Energy deficiency and oxidative stress are interconnected during ischemia/reperfusion (I/R) and serve as potential targets for the treatment of cerebral ischemic stroke. Baicalin is a neuroprotective antioxidant, but the underlying mechanisms are not fully revealed. PURPOSE: This study explored whether and how baicalin rescued neurons against ischemia/reperfusion (I/R) attack by focusing on the regulation of neuronal pyruvate dehydrogenase kinase 2 (PDK2)-pyruvate dehydrogenase (PDH) axis implicated with succinate dehydrogenase (SDH)-mediated oxidative stress. STUDY DESIGN: The effect of the tested drug was explored in vitro and in vivo with the model of oxygen-glucose deprivation/reoxygenation (OGD/R) and middle cerebral artery occlusion/reperfusion (MCAO/R), respectively. METHODS: Neuronal damage was evaluated according to cell viability, infarct area, and Nissl staining. Protein levels were measured by western blotting and immunofluorescence. Gene expression was investigated by RT-qPCR. Mitochondrial status was also estimated by fluorescence probe labeling. RESULTS: SDH activation-induced excessive production of reactive oxygen species (ROS) changed the protein expression of Lon protease 1 (LonP1) and hypoxia-inducible factor-1ɑ (HIF-1ɑ) in the early stage of I/R, leading to an upregulation of PDK2 and a decrease in PDH activity in neurons and cerebral cortices. Treatment with baicalin prevented these alterations and ameliorated neuronal ATP production and survival. CONCLUSION: Baicalin improves the function of the neuronal PDK2-PDH axis via suppression of SDH-mediated oxidative stress, revealing a new signaling pathway as a promising target under I/R conditions and the potential role of baicalin in the treatment of acute ischemic stroke.


Assuntos
Flavonoides , Neurônios , Fármacos Neuroprotetores , Estresse Oxidativo , Piruvato Desidrogenase Quinase de Transferência de Acetil , Traumatismo por Reperfusão , Flavonoides/farmacologia , Animais , Traumatismo por Reperfusão/tratamento farmacológico , Neurônios/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Piruvato Desidrogenase Quinase de Transferência de Acetil/metabolismo , Fármacos Neuroprotetores/farmacologia , Succinato Desidrogenase/metabolismo , Masculino , Espécies Reativas de Oxigênio/metabolismo , Infarto da Artéria Cerebral Média/tratamento farmacológico , Ratos Sprague-Dawley , Sobrevivência Celular/efeitos dos fármacos , Ratos , Antioxidantes/farmacologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo
15.
Bioresour Technol ; 399: 130631, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38554760

RESUMO

Macroalgae biomass has been considered as a promising renewable feedstock for lactic acid production owing to its lignin-free, high carbohydrate content and high productivity. Herein, the D-lactic acid production from red macroalgae Gelidium amansii by Pediococcus acidilactici was investigated. The fermentable sugars in G. amansii acid-prehydrolysate were mainly galactose and glucose with a small amounts of xylose. P. acidilactici could simultaneously ferment the mixed sugars of galactose, glucose and xylose into D-lactic acid at high yield (0.90 g/g), without carbon catabolite repression (CCR). The assimilating pathways of these sugars in P. acidilactici were proposed based on the whole genome sequences. Simultaneous saccharification and co-fermentation (SSCF) of the pretreated and biodetoxified G. amansii was also conducted, a record high of D-lactic acid (41.4 g/L) from macroalgae biomass with the yield of 0.34 g/g dry feedstock was achieved. This study provided an important biorefinery strain for D-lactic acid production from macroalgae biomass.


Assuntos
Algas Comestíveis , Ácido Láctico , Rodófitas , Alga Marinha , Fermentação , Xilose/metabolismo , Galactose/metabolismo , Alga Marinha/metabolismo , Glucose/metabolismo
16.
Int J Biol Macromol ; 269(Pt 1): 132055, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38704073

RESUMO

Pretreatment is the key step to convert lignocelluloses to sustainable biofuels, biochemicals or biomaterials. In this study, a green pretreatment method based on choline chloride-lactic acid deep eutectic solvent (ChCl-LA) and niobium-based single-atom catalyst (Nb/CN) was developed for the fractionation of corn straw and further enzymatic hydrolysis of cellulose. With this strategy, significant lignin removal of 96.5 % could be achieved when corn straw was pretreated by ChCl-LA (1:2) DES over Nb/CN under 120 °C for 6 h. Enzymatic hydrolysis of the cellulose-enriched fraction (CEF) presented high glucose yield of 92.7 % and xylose yield of 67.5 %. In-depth investigations verified that the high yields of fractions and monosaccharides was attributed to the preliminary fractionation by DES and the deep fractionation by Nb/CN. Significantly, compared to other reported soluble catalysts, the synthesized single-atom catalyst displayed excellent reusability by simple filtration and enzymatic hydrolysis. The recyclability experiments showed that the combination of ChCl-LA DES and Nb/CN could be repeated at least three times for corn straw fractionation, moreover, the combination displayed remarkable feedstock adaptability.


Assuntos
Colina , Solventes Eutéticos Profundos , Ácido Láctico , Lignina , Nióbio , Lignina/química , Nióbio/química , Catálise , Colina/química , Hidrólise , Solventes Eutéticos Profundos/química , Ácido Láctico/química , Zea mays/química , Fracionamento Químico/métodos
17.
J Biol Inorg Chem ; 18(2): 211-221, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23322168

RESUMO

The neutral protease WQ from Bacillus cereus is stable in various aqueous organic mixtures, with the exception of those containing acetonitrile (ACN) and dimethylformamide (DMF). The stability of the enzyme in aqueous hydrophilic solvents was dramatically enhanced with the addition of calcium ions, with the degree of improvement in the half-life relative to different solutions ranging from fourfold to more than 70-fold. Studies of the kinetic constants showed that calcium ions induced slight conformational changes in the active site of the enzyme in aqueous ACN. We investigated the molecular mechanisms underlying this stabilizing effect by employing a combination of biophysical techniques and molecular dynamics simulation. In aqueous ACN, the intrinsic fluorescence and circular dichroism analysis demonstrated that the addition of calcium ions induced a relatively compact conformation and maintained both the native-like microenvironment near the tryptophan residues and the secondary structure. Alternatively, homology modeling confirmed the location of four calcium-ion-binding sites in the enzyme, and molecular dynamics simulation revealed that three other calcium ions were bound to the surface of the enzyme. Calcium ions, known as a type of kosmotrope, can strongly bond with water molecules, thus aiding in the formation of the regional hydration shell required for the maintenance of enzyme activity. In addition, the introduction of calcium ions resulted in the formation of additional ionic interactions, providing propitious means for protein stabilization. Thus, the stronger intramolecular interactions were also expected to contribute partially to the enhanced stability of the enzyme in an aqueous organic solvent.


Assuntos
Bacillus cereus/enzimologia , Proteínas de Bactérias/química , Cálcio/química , Endopeptidases/química , Acetonitrilas/química , Caseínas/química , Domínio Catalítico , Complexos de Coordenação/química , Estabilidade Enzimática , Meia-Vida , Ligação de Hidrogênio , Cinética , Simulação de Dinâmica Molecular , Ligação Proteica , Estrutura Secundária de Proteína , Proteólise , Soluções , Solventes/química , Homologia Estrutural de Proteína , Água/química
18.
Biomed Chromatogr ; 27(11): 1380-6, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23703236

RESUMO

In order to accurately investigate the preclinical pharmacokinetics of (R)-(+)-rabeprazole sodium injection, a reliable high-performance liquid chromatography (HPLC) method was developed using a Chiral-AGP column to prove that there is no chiral bioconversion of (R)-(+)-rabeprazole to (S)-(-)-rabeprazole in beagle dogs after single intravenous administration of (R)-(+)-rabeprazole sodium injection. An HPLC-tandem mass spectrometry (HPLC-MS/MS) method for analysis of (R)-(+)-rabeprazole was developed and validated, and used to acquire the pharmacokinetic parameters in beagle dogs. (R)-(+)-Rabeprazole and internal standard omeprazole were extracted from plasma samples by protein precipitation and separated on a C18 column using methanol-5 mm ammonium acetate as mobile phase. Detection was performed using a turbo-spray ionization source and mass spectrometric positive multi-reaction monitoring mode. The linear relationship was achieved in the range from 2.5 to 5000 ng/mL. The method also afforded satisfactory results in terms of sensitivity, specificity, precision, accuracy and recovery as well as the stability of the analyte under various conditions, and was successfully applied to a preclinical pharmacokinetic study in beagle dogs after single intravenous administrations of (R)-(+)-rabeprazole sodium injection at 0.33, 2 and 6 mg/kg.


Assuntos
Antiulcerosos/sangue , Cromatografia Líquida de Alta Pressão/métodos , Rabeprazol/sangue , Espectrometria de Massas em Tandem/métodos , Animais , Antiulcerosos/química , Cães , Feminino , Limite de Detecção , Masculino , Rabeprazol/química , Estereoisomerismo
19.
Nanomaterials (Basel) ; 13(4)2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36839004

RESUMO

Nanoflower-like MoS2 deposited on the surface of rectangular CaTiO3(CTO) was designed and synthesized via a simple template-free strategy. Through SEM, TEM, and other characterization methods, the MoS2 nanoflowers were confirmed to be well deposited on the surface of CTO. LED was used as the visible light source, and rhodamine B (RhB) in an aqueous solution was used as the model pollutant to assess the photodegradation activity of the samples. The results showed that the MoS2/CaTiO3(MCTO) composite significantly improved the photocatalytic degradation of rhodamine B (RhB) in water, compared with a single CTO, and with the MCTO-2 composite photocatalysts, 97% degradation of RhB was achieved in 180 min, and its photocatalytic activity was about 5.17 times higher than that of the bare CTO. The main reasons for enhancing photocatalytic performance are the strong interaction between the nanoflower-like MoS2 and rectangular CTO, which can lead to the effective separation of electron transfer and photoexcited electron-hole pairs in MCTO composites. This work provides a new notion for researching an effective method of recycling catalytic materials.

20.
Exp Ther Med ; 25(4): 175, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37006871

RESUMO

The present study aimed to investigate the clinical characteristics of diffuse pulmonary lymphangioma (DPL) in children to improve the diagnosis and treatment of this disease. A case of pediatric DPL was observed for its clinical symptoms, imaging features, lung biopsy pathological characteristics and immunohistochemical phenotypes, and relevant literature was also reviewed. The main clinical manifestations of this pediatric patient were a cough, shortness of breath, hemoptysis, bloody chylothorax and pericardial effusion. Chest computed tomography showed a grid-like shadow and markedly thickened interlobular septa. Pathological examination revealed lymphatic vessel hyperplasia and expansion. Immunohistochemistry showed positive staining of lymphatic endothelial cells CD31 and D2-40. The patient's condition improved after combined treatment with methylprednisone, propranolol, sirolimus and somatostatin, whose bloody chylothorax also achieved good therapeutic effect after conservative treatment. Overall, the clinical and imaging appearances of DPL are lack of characterization, and its clinical manifestations include cough, shortness of breath and chylothorax. Computed tomography may show mesh-like shadows of both lungs and thickened interlobular septa. The definite diagnosis of DPL depends on biopsy pathology. In addition to this case, B-ultrasound-guided puncture biopsy is effective and safe, and propranolol-sirolimus treatment has a certain effect, but the clinical effect may be different. Conservative treatment of pleural effusion can result in better curative effect.

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