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1.
Artigo em Inglês | MEDLINE | ID: mdl-34595707

RESUMO

This study aims to explore the driving determinants on the export-related carbon intensity (ECI) of China, to better understand the impact of international trade on climate change governance and facilitate China's carbon intensity mitigation goals. First, China's ECI evolution and its gaps with the USA and India are measured during 2002-2014. Then, the main drivers of China's ECIvert study further discusses the influencing factors of ECI in the manufacturing industry using the environmental-extended STIRPAT model and GMM method. The results show that (1) China's overall ECI increases from 1.50 Kg/US$ in 2002 to 1.92 Kg/US$ in 2005 and then decreases to 1.27 Kg/US$ in 2014. The ECI of the manufacturing industry is significantly higher than that of the agriculture and service industry. China's ECI gap with the USA is greater than that with India, and both show a downward trend. (2) Carbon emission coefficient is the domain factor to reduce China's ECI during 2002-2014; the effects of the value-added coefficient, input-output structure, and final demand are limited. The input structure dominantly expands China's ECI gaps both with the USA and India, followed by the value-added coefficient. The carbon emission coefficient enlarges the ECI gap with the USA while reduces that with India. (3) Industrial productivity and value-added rate are negatively correlated with ECI in the manufacturing industry, while per capita capital stock plays the opposite role. The positive correlation between energy intensity and CIE becomes significant after distinguishing technology heterogeneity. In contrast to the non-tech-intensive manufacturing industry, the increase of backward GVCs participation of tech-intensive ones will reduce the ECI. The threshold effect of backward GVCs participation exists in the whole manufacturing industry. Targeted ECI reduction policy implications are suggested.

2.
Artigo em Inglês | MEDLINE | ID: mdl-34636536

RESUMO

Although organic artificial enzymes have been reported as biomimetic oxidation catalysts and are widely used for colorimetric biosensors, developing organic artificial enzymes with high enzymatic activity is still a challenge. Two-dimensional (2D) covalent organic frameworks (COFs) have shown superior potential in biocatalysts because of their periodic π-π arrays, tunable pore size and structure, large surface area, and thermal stability. The interconnection of electron acceptor and donor building blocks in the 2D conjugated COF skeleton can lead to narrower band gaps and efficient charge separation and transportation and thus is helpful to improve catalytic activity. Herein, a donor-acceptor 2D COF was synthesized using tetrakis(4-aminophenyl)pyrene (Py) as an electron donor and thieno[3,2-b]thiophene-2,5-dicarbaldehyde (TT) as an electron acceptor. Under visible light irradiation, the donor-acceptor 2D COF exhibited superior enzymatic catalytic activity, which could catalyze the oxidation of chromogenic substrates such as 3,3',5,5'-tetramethylbenzidine (TMB) by the formation of superoxide radicals and holes. Based on the above property, the photoactivated donor-acceptor 2D COF with enzyme-like catalytic properties was designed as a robust colorimetric probe for cheap, highly sensitive, and rapid colorimetric detection of glutathione (GSH); the corresponding linear range of GSH was 0.4-60 µM, and the limit of detection was 0.225 µM. This study not only presents the construction of COF-based light-activated nanozymes for environmentally friendly colorimetric detection of GSH but also provides a smart strategy for improving nanozyme activity.

3.
Bioconjug Chem ; 32(9): 2032-2042, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34469136

RESUMO

Bacterial biofilm, as a natural and renewable material, is a promising architecture for enzyme immobilization. In this study, we have demonstrated the feasibility of an Escherichia coli biofilm to immobilize a self-assembly multienzyme complex by the covalent interaction between a peptide SpyTag and its protein partner SpyCatcher. The SpyTag-labeled biofilm is displayed on the surface of E. coli by overexpressing the recombinant CsgA-SpyTag, in which CsgA is capable of forming biofilms. This SpyTag bearing biofilm is used to bind with SpyCatcher bearing synthetic mini-scaffoldin, which also contains a carbohydrate-binding module 3 (CBM3), and four different cohesins from different microorganisms. CBM3 was used to bind with cellulose, while the four different cohesins were used to recruit four dockerin-containing cascade enzymes, which were subsequently applied to convert starch to myo-inositol. Compared to the free enzyme mixture, the biofilm-immobilized enzyme complex exhibited a 4.28 times increase in initial reaction rate in producing myo-inositol from 10 g/L maltodextrin (a derivative of starch). Additionally, this biofilm-immobilized enzyme complex showed much higher recycle ability than the enzyme complex which was immobilized on a regenerated amorphous cellulose (RAC) system. In conclusion, the biofilm-mediated immobilization of the enzymatic biosystem provides a promising strategy to increase the reaction rate and enhance the stability of an in vitro enzymatic biosystem, exhibiting high potential to improve the efficiency of an in vitro biosystem.

4.
Talanta ; 235: 122789, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517647

RESUMO

In this work, core-shell structured Ti4+-immobilized magnetic covalent organic frameworks (denoted as Fe3O4@TAPTDHTA-Ti4+ composites) were prepared for enhanced phosphopeptide enrichment by one-pot synthesis of COFs shell with inherent bifunctional groups on Fe3O4 NPs and further Ti4+ immobilization. The widely distributed bifunctional groups could provide abundant chelating sites for Ti4+ immobilizing. Combining with the high specific surface area and mesoporous structure, the Fe3O4@TAPTDHTA-Ti4+ composites exhibited excellent enrichment efficiency for phosphopeptides, such as low detection limit (0.05 fmol µL-1), high selectivity (1:5000 of molar ratio of ß-casein/bovine serum albumin (BSA) tryptic digests), high adsorption capacity (62.9 µg mg-1) and strong size-exclusive effect (1:250:250 of molar ratio of ß-casein tryptic digest/ß-casein/BSA). In addition, this method was general for immobilizing other metal ions (Zr4+ and Fe3+). Notably, the Fe3O4@TAPTDHTA-Fe3+ composites exhibited controllable affinity towards mono-phosphopeptides and multi-phosphopeptides. Furthermore, the Fe3O4@TAPTDHTA-Ti4+ composites were successfully applied to selectively capture phosphopeptides from complex biological samples including the tryptic digest of nonfat milk, human serum and human saliva. More significantly, 3333 phosphopeptides derived from 1409 phosphoproteins with 3492 phosphorylation sites were clearly identified from the tryptic digest of HeLa cell lysate. In addition to providing a potential excellent enrichment probe for comprehensive phosphoproteomic analysis, this study also offers a new perspective for the functionalization of COFs.


Assuntos
Estruturas Metalorgânicas , Fosfopeptídeos , Animais , Bovinos , Feminino , Células HeLa , Humanos , Fenômenos Magnéticos , Titânio
5.
Chem Commun (Camb) ; 57(60): 7362-7365, 2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34196343

RESUMO

A facile strategy was introduced for room-temperature controllable synthesis of hierarchically flower-like hollow COFs (FHF-COFs). Furthermore, the universality for synthesis of the HFH-COFs was validated by altering the building units. Inspired by the unique morphology, extremely large surface area and good chemical stability, HFH-COFs could serve as an attractive adsorption probe by loading with gold nanoparticles and be applied to enrichment of brain natriuretic peptide from human serum. This work opens up a whole new approach for controllable synthesis of the HFH-COFs at room temperature and expands the application of COFs as a promising enrichment probe for complex biological samples.


Assuntos
Estruturas Metalorgânicas/química , Peptídeo Natriurético Encefálico/isolamento & purificação , Adsorção , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/síntese química , Peptídeo Natriurético Encefálico/sangue , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
6.
Biosci Trends ; 15(3): 161-170, 2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34078766

RESUMO

This study aimed to investigate the value of multidisciplinary team (MDT) management in minimally invasive treatment of complex intrahepatic bile duct stones (IHDs) by laparoscopy, choledochoscopy and percutaneous choledochoscopy. The characteristics, perioperative index, complication rate and minimally invasive rate of patients in MDT group (n = 75) and non-MDT group (n = 70) were compared. The members of MDT include doctors in ultrasound, imaging, hepatobiliary and pancreatic surgery, anaesthesia and intensive care medicine. The results showed that minimally invasive surgery reduced the incidence of postoperative residual stones, OR (95% CI) = 0.365 (0.141-0.940) (p = 0.037). MDT reduced the operation time, OR (95% CI) = 0.406 (0.207-0.796) (p = 0.009). Minimally invasive surgery significantly reduced intraoperative bleeding, OR (95% CI) = 0.267 (0.133-0.534) (p < 0.001). Minimally invasive surgery also reduced hospitalization time, OR (95% CI) = 0.295 (0.142-0.611) (p = 0.001). The stone clearance rates of MDT group and non-MDT group were 81.33% and 81.43% respectively. In the MDT group, the operative time was less than that in the non-MDT group (p = 0.010); the intraoperative bleeding volume was significantly less than that in the non-MDT group (p < 0.001); the hospitalization time was less than that in the non-MDT group (p = 0.001). Minimally invasive operation rate:48 cases (64.00%) in MDT group were significantly higher than 17 cases (24.29%) in non-MDT group (p < 0.001). In conclusion, minimally invasive procedures can be selected more through MDT. MDT can shorten the operation time, and minimally invasive surgery can reduce the incidence of residual stones, reduce intraoperative bleeding, and may shorten hospital stay. Therefore, MDT management model can provide personalized and minimally invasive surgical protocol for patients with complex IHD, which has high application value.

7.
J Chromatogr A ; 1651: 462329, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34157477

RESUMO

Efficiently tunable capture of the glycosylated/phosphorylated proteins is critical to meet the need of in-depth glycoproteome and phosphoproteome studies. Reported here is a new bifunctional polymer monolithic column by introducing benzeneboronic acid and phosphonic acid onto monolithic column (denoted as poly (EDMA-co-VPBA-co-VPA) monolith) for tunable and specific enrichment of glycoproteins and phosphoproteins via switching different mobile phases. Based on boronate affinity and immobilized metal affinity, the as-prepared poly (EDMA-co-VPBA-co-VPA) monolith exhibited superior performance in selective separation of small molecules and biomacromolecules containing cis-diol/phosphate groups or not. And the frontal chromatography analysis showed that the binding capacity of the poly (EDMA-co-VPBA-co-VPA) monolith towards horseradish peroxidase (HRP, glycoprotein) or ß-casein (phosphoprotein) is four-fold higher than that of bovine serum albumin (BSA, non-glycosylated/phosphorylated protein). Furthermore, combined with mass spectrometry identification, the successful application in specific enrichment of glycopeptides/phosphopeptides from tryptic digests of HRP/ß-casein and direct capture of low abundant endogenous phosphopeptides from human serum proved great practicability in complex samples. This study provides a novel insight for fabricating the monolithic columns with multifunctionalization to facilitate further post-translational modification (PTM)-proteomics development.


Assuntos
Análise Química do Sangue/instrumentação , Cromatografia/instrumentação , Glicoproteínas/isolamento & purificação , Fosfoproteínas/isolamento & purificação , Polímeros/química , Ácidos Borônicos/química , Caseínas/metabolismo , Glicopeptídeos/isolamento & purificação , Peroxidase do Rábano Silvestre/metabolismo , Humanos , Fosfopeptídeos/química , Ácidos Fosforosos/química , Soroalbumina Bovina/isolamento & purificação
8.
J Med Chem ; 64(15): 11247-11266, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34180670

RESUMO

The emergence of multidrug-resistant bacteria has major issues for treating bacterial pneumonia. Currently, anoplin (GLLKRIKTLL-NH2) is a natural antimicrobial candidate derived from wasp venom. In this study, a series of new antimicrobial peptide (AMP) anoplin analogues were designed and synthesized. The relationship between their biological activities and their positive charge, hydrophobicity, amphipathicity, and secondary structure are described. The characteristic shared by these peptides is that positively charged amino acids and hydrophobic amino acids are severally arranged on the hydrophilic and hydrophobic surface of the α-helix to form a completely amphiphilic structure. To achieve ideal AMPs, below the range of the threshold of the cytotoxicity and hemolytic activity, their charges and hydrophobicity were increased as much. Among the new analogues, A-21 (KWWKKWKKWW-NH2) exhibited the greatest antimicrobial activity (geometric mean of minimum inhibitory concentrations = 4.76 µM) against all the tested bacterial strains, high bacterial cell selectivity in vitro, high effectiveness against bacterial pneumonia in mice infected with Klebsiella pneumoniae, and low toxicity in mice (LD50 = 82.01 mg/kg). A-21 exhibited a potent bacterial membrane-damaging mechanism and lipopolysaccharide-binding ability. These data provide evidence that A-21 is a promising antimicrobial candidate for the treatment of bacterial pneumonia.

9.
Ying Yong Sheng Tai Xue Bao ; 32(4): 1230-1240, 2021 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-33899391

RESUMO

In this study, desert grassland, grassland edge, shrubland edge, shrubland were selec-ted as four transition sites in a nearly 30 years typical desert grassland-shrubland mosaic formed by anthropogenic shrub introduction. Soil properties and soil microbial characteristics under vegetation patches and bare interspace in each site were investigated to examine the responses of soil nitrogen to the desert grassland-shrubland state transition. It was shown that the aboveground biomass increased with transition from desert grassland to shrubland. Annual herbs increased largely with the introduction of shrubs. Soil moisture, microbial biomass and total nitrogen and carbon decreased with the transition. The abundance of microogranisms was lower in grassland edge and shrubland edge, and then increased in shrubland, which was slightly higher than that of desert grassland. With respect to nitrogen, nitrate content reached the highest level of 28.45 mg N·kg-1 and ammonium reached the lowest level of 4.81 mg N·kg-1 in shrubland, which were significantly increased by 52.3% and decreased by 10.4% compared with desert grassland. In addition, soil moisture and microbial biomass nitrogen was positively correlated across all sites. The relationship between mine-ralized nitrogen and soil moisture was non-linear, as they were positively correlated in desert grassland and grassland edge, but negatively correlated in shrubland edge and shrubland. During the 30-year transition from desert grassland to shrubland, our results showed that soil total nitrogen and microbial biomass nitrogen were significantly decreased, but mineralized nitrogen, especially for nitrate, significantly increased over time, indicating that soil nitrification was inhibited in desert grassland but accelerated in shrubland.


Assuntos
Nitrogênio , Solo , Carbono/análise , China , Ecossistema , Pradaria , Nitrogênio/análise
10.
ACS Infect Dis ; 7(6): 1619-1637, 2021 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-33829758

RESUMO

With the aim of tackling the increasingly serious antimicrobial resistance and improving the clinical potential of AMPs, a facile de novo strategy was adopted in this study, and a series of new peptides comprising repeating unit (WRX)n (X represents I, L, F, W, and K; n = 2, 3, 4, or 5) and amidation at C-terminus were designed. Most of the newly designed peptides exhibited a broad range of excellent antimicrobial activities against various bacteria, especially difficult-to-kill multidrug-resistant bacteria clinical isolates. Among (WRK)4 and (WRK)5, with n = 4 and n = 5 of repeating unit WRK, the highest selectivity for anionic bacterial membranes over a zwitterionic mammalian cell membrane is presented with strong antimicrobial potential and low toxicity. Additionally, both (WRK)4 and (WRK)5 emerged with fast killing speed and low tendency of resistance in sharp contrast to the conventional antibiotics ciprofloxacin, gentamicin, and imipenem, as well as having antimicrobial activity through multiple mechanisms including a membrane-disruptive mechanism and an intramolecular mechanism (nucleic acid leakage, DNA binding and ROS generation) characterized by a series of assays. Furthermore, (WRK)4 exerted impressive therapeutic effects in vivo similarly to polymyxin B but displayed much lower toxicity in vivo than polymyxin B. Taken together, the newly designed peptides (WRK)4 and (WRK)5 presented tremendous potential as novel antimicrobial candidates in response to the growing antimicrobial resistance.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana Múltipla , Animais , Antibacterianos/farmacologia , Bactérias , Testes de Sensibilidade Microbiana , Proteínas Citotóxicas Formadoras de Poros
11.
Front Immunol ; 12: 649463, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33868286

RESUMO

Macrophages polarized to different phenotypes critically contribute to colitis development by coordinating inflammatory and anti-inflammatory processes. Herein, targeting the balance between the pro-inflammatory M1 and the anti-inflammatory M2 macrophage phenotypes can be a novel therapeutic approach for colitis. In the present study, we firstly demonstrated that tiliroside possessed the ability to alleviate the clinical symptoms of colitis as evidenced by decreased disease activity index (DAI) scores, longer colon length, reduced myeloperoxidase (MPO) activity, and improvement of colonic pathological damage in vivo. Furthermore, we showed that tiliroside modulated the balance between M1 and M2 macrophages toward a more anti-inflammatory status in colonic lamina propria but has little effect on the T cell population and epithelial barrier function in colitis mice. The macrophage depletion study further showed the protective effect of tiliroside was macrophage dependent in vivo. Mechanistically, our study demonstrated that tiliroside regulated cellular metabolism by inhibiting aerobic glycolysis in LPS and IFNγ stimulated macrophages. At the molecular level, tiliroside facilitated the proteasomal degradation of HIF-1α and downregulated mRNA expressions of HIF-1α dependent glycolytic enzymes in macrophages. Collectively, our data highlight the aberrant M1/M2 macrophage polarization in the initiation and development of ulcerative colitis and put forth the stage for considering tiliroside as a metabolic regulator in reprogramming macrophage polarization, which may serve as a promising therapeutic approach for treatment of inflammation-associated and metabolic disorders.


Assuntos
Anti-Inflamatórios/farmacologia , Colite Ulcerativa/tratamento farmacológico , Flavonoides/farmacologia , Macrófagos/efeitos dos fármacos , Animais , Anti-Inflamatórios/uso terapêutico , Colite Ulcerativa/induzido quimicamente , Colite Ulcerativa/imunologia , Colite Ulcerativa/patologia , Colo/efeitos dos fármacos , Colo/imunologia , Colo/patologia , Sulfato de Dextrana/administração & dosagem , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Feminino , Flavonoides/uso terapêutico , Glicólise/efeitos dos fármacos , Glicólise/imunologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Camundongos , Cultura Primária de Células , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/imunologia , Células THP-1
12.
Plant Biotechnol J ; 19(8): 1644-1657, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33740293

RESUMO

Circadian clock, an endogenous time-setting mechanism, allows plants to adapt to unstable photoperiod conditions and induces flowering with proper timing. In Arabidopsis, the central clock oscillator was formed by a series of interlocked transcriptional feedback loops, but little is known in rice so far. By MutMap technique, we identified the candidate gene OsLHY from a later flowering mutant lem1 and further confirmed it through genetic complementation, RNA interference knockdown, and CRISPR/Cas9-knockout. Global transcriptome profiling and expression analyses revealed that OsLHY might be a vital circadian rhythm component. Interestingly, oslhy flowered later under ≥12 h day length but headed earlier under ≤11 h day length. qRT-PCR results exhibited that OsLHY might function through OsGI-Hd1 pathway. Subsequent one-hybrid assays in yeast, DNA affinity purification qPCR, and electrophoretic mobility shift assays confirmed OsLHY could directly bind to the CBS element in OsGI promoter. Moreover, the critical day length (CDL) for function reversal of OsLHY in oslhy (11-12 h) was prolonged in the double mutant oslhy osgi (about 13.5 h), indicating that the CDL set by OsLHY was OsGI dependent. Additionally, the dual function of OsLHY entirely relied on Hd1, as the double mutant oslhy hd1 showed the same heading date with hd1 under about 11.5, 13.5, and 14 h day lengths. Together, OsLHY could fine-tune the CDL by directly regulating OsGI, and Hd1 acts as the final effector of CDL downstream of OsLHY. Our study illustrates a new regulatory mechanism between the circadian clock and photoperiodic flowering.


Assuntos
Oryza , Fotoperíodo , Ritmo Circadiano/genética , Flores/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
13.
Stem Cell Res Ther ; 12(1): 196, 2021 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-33743829

RESUMO

BACKGROUND: The senescence of dermal fibroblasts (DFLs) leads to an imbalance in the synthesis and degradation of extracellular matrix (ECM) proteins, presenting so-called senescence-associated secretory phenotype (SASP), which ultimately leads to skin aging. Recently, mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have been recognized as a promising cell-free therapy for degenerative diseases, which opens a new avenue for skin aging treatment. METHODS: In this study, we utilized chitosan (CS) hydrogel for effective loading and sustained release of EVs. In vitro, we explored the rejuvenation effects of CS hydrogel-incorporated EVs (CS-EVs) on replicative senescence DFLs through a series of experiments such as senescence-associated ß-galactosidase (SA-ß-gal) staining, RT-PCR, and Western blot analysis. Besides, we employed local multi-site subcutaneous injection to treat skin aging of naturally aged mice with CS-EVs and DiI fluorescent dye was used to label EVs to achieve in vivo real-time tracking. RESULTS: CS-EVs can significantly improve the biological functions of senescent fibroblasts, including promoting their proliferation, enhancing the synthesis of ECM proteins, and inhibiting the overexpression of matrix metalloproteinases (MMPs). Moreover, CS hydrogel could prolong the release of EVs and significantly increase the retention of EVs in vivo. After CS-EVs subcutaneous injection treatment, the aging skin tissues showed a rejuvenation state, manifested explicitly as the enhanced expression of collagen, the decreased expression of SASP-related factors, and the restoration of tissue structures. CONCLUSIONS: CS hydrogel-encapsulated EVs could delay the skin aging processes by ameliorating the function of aging DFLs. Our results also highlight the potential of CS hydrogel-encapsulated EVs as a novel therapeutic strategy for improving aging skin to rejuvenation.


Assuntos
Quitosana , Vesículas Extracelulares , Células-Tronco Mesenquimais , Animais , Senescência Celular , Fibroblastos , Hidrogéis , Camundongos , Rejuvenescimento
14.
Carbohydr Polym ; 260: 117772, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33712130

RESUMO

Nanoparticle-polymer composites are important functional materials but structural control of their assembly is challenging. Owing to its crystalline internal structure and tunable nanoscale morphology, cellulose is promising polymer scaffold for templating such composite materials. Here, we show bottom-up synthesis of reducing end thiol-modified cellulose chains by iterative bi-enzymatic ß-1,4-glycosylation of 1-thio-ß-d-glucose (10 mM), to a degree of polymerization of ∼8 and in a yield of ∼41% on the donor substrate (α-d-glucose 1-phosphate, 100 mM). Synthetic cellulose oligomers self-assemble into highly ordered crystalline (cellulose allomorph II) material showing long (micrometers) and thin nanosheet-like morphologies, with thickness of 5-7 nm. Silver nanoparticles were attached selectively and well dispersed on the surface of the thiol-modified cellulose, in excellent yield (≥ 95%) and high loading efficiency (∼2.2 g silver/g thiol-cellulose). Examined against Escherichia coli and Staphylococcus aureus, surface-patterned nanoparticles show excellent biocidal activity. Bottom-up approach by chemical design to a functional cellulose nanocomposite is presented. Synthetic thiol-containing nanocellulose can expand the scope of top-down produced cellulose materials.


Assuntos
Antibacterianos/química , Celulose/química , Nanopartículas Metálicas/química , Nanocompostos/química , Compostos de Sulfidrila/química , Antibacterianos/farmacologia , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Escherichia coli/efeitos dos fármacos , Nanocompostos/toxicidade , Prata/química , Staphylococcus aureus/efeitos dos fármacos
15.
Biochem Pharmacol ; 186: 114470, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33610592

RESUMO

In response to the dramatically increasing antimicrobial resistance, a series of new symmetric peptides were designed and synthesized in this study by a "WWW" motif as the symmetric center, arginine as the positive charge amino acid and the terminus symmetrically tagged with hydrophobic amino acids. Amongst the new symmetric peptide FRRW (FRRWWWRRF-NH2) presented the highest cell selectivity for bacteria over mammalian cell and exerted excellent antimicrobial potential against a broad of bacteria, especially difficult-to-kill multidrug-resistant strains clinical isolates. FRRW also displayed perfect stability in physiological salt ions and rapid killing speed as well as acted on multiple mechanisms including non-receptor mediated membrane and intra-molecular mechanisms. Importantly, FRRW emerged a low tendency of resistance in contrast to traditional antibiotics ciprofloxacin and gentamicin. What's more, FRRW could resist or alleviate or even reverse the ciprofloxacin- and gentamicin-resistance by changing the permeability of bacterial membrane and inhibiting the efflux pumps of bacteria. Furthermore, FRRW exhibited remarkable effectiveness and higher safety in vivo than polymyxin B. In summary, the new symmetric peptide FRRW was promised to be as a new antimicrobial candidate for overcoming the increasing bacterial resistance.


Assuntos
Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Proteínas Citotóxicas Formadoras de Poros/química , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Animais , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana Múltipla/fisiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana/métodos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Relação Estrutura-Atividade
16.
J Org Chem ; 86(3): 2135-2157, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33433196

RESUMO

A concise and diastereoselective construction of the ABCD ring system of spirochensilide A is described. The key steps of this synthesis are a semipinacol rearrangement reaction to stereoselectively construct the AB ring system bearing two vicinal quaternary chiral centers and a Co-mediated Pauson-Khand reaction to form the spiro-based bicyclic CD ring system. This chemistry leads to the stereoselective synthesis of 13(R)-demethyl spirochensilide A, paving the way for the first asymmetric total synthesis of (-)-spirochensilide A.


Assuntos
Triterpenos , Estereoisomerismo
17.
J Org Chem ; 86(3): 2158-2172, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33481592

RESUMO

The final phase of the total synthesis of (-)-spirochensilide A is described. A tungsten-mediated cyclopropene-based Pauson-Khand reaction was developed to form the spiral CD ring system with desired stereochemistry at the C13 quaternary center. Other important steps enabling completion of this synthesis included an intermolecular aldol condensation to link the ABCD core with the EF fragment and a Cu-mediated 1,4-addition to stereoselectively install the C21 stereogenic center. The chemistry developed for this total synthesis of (-)-spirochensilide A (1) will aid the synthesis of polycyclic natural products bearing this unique spiral ring system.


Assuntos
Produtos Biológicos , Triterpenos , Estereoisomerismo
18.
Acta Biomater ; 122: 199-210, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33453408

RESUMO

Perinatal-related tissues, such as the placenta, umbilical cord, and amniotic membrane, are generally discarded after delivery and are increasingly attracting attention as alternative sources for decellularized extracellular matrix (dECM) isolation. Recent studies indicate that glycosaminoglycans (GAGs) in the dECM play key roles during tissue regeneration. However, the dECM is organ specific, and the glycosaminoglycanomics of dECMs from perinatal tissues and the regulatory function of GAGs have been poorly investigated. In this study, we explored the glycosaminoglycanomics of dECMs from the placenta, umbilical cord and amniotic membrane. We hypothesized that the therapeutic effects of dECMs are related to the detailed composition of GAGs. Hydrogels of dECM derived from perinatal tissues were generated, and glycosaminoglycanomics analysis was employed to identify the cues that promote tissue repair and regeneration in a murine cutaneous wound-healing model. We utilized highly sensitive liquid chromatography-tandem mass spectrometry for glycosaminoglycanomics analysis. Our results revealed that placenta-derived dECM (PL-dECM) hydrogel has higher contents of chondroitin sulfate (CS) and heparan sulfate (HS). In addition, molecular imaging showed that the PL-dECM hydrogel exerted the best anti-inflammatory and proangiogenic effects in the skin wound healing model. Further in vitro analyses demonstrated that CS with 6-O-sulfo group (CS-6S) has an anti-inflammatory effect, while HS with 6-O-sulfo group (HS-6S) plays a crucial role in angiogenesis. In conclusion, this study highlights the critical roles of GAGs in perinatal tissue-derived dECMs by promoting angiogenesis and inhibiting inflammation and indicates that it is feasible to utilize 6-sulfated GAG-enriched placental dECM hydrogel as an attractive candidate for tissue engineering and drug delivery.


Assuntos
Matriz Extracelular , Glicosaminoglicanos , Animais , Feminino , Camundongos , Placenta , Gravidez , Cicatrização
19.
Environ Sci Pollut Res Int ; 28(16): 20034-20044, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33405165

RESUMO

The high NO2/NOX ratio in the after-treatment system is beneficial to its performance and achieved by NO catalytic conversion in diesel oxidation catalyst (DOC) located upstream (CRDPF), catalytic DPF (CDPF), or a combination of both (CCDPF). In order to effectively control the emission of particulates and nitrogen oxides, various types of diesel particulate filter models are established to compare NO2 catalytic formation, consumption, and efflux. The results show that the catalytic performance of NO conversion is limited by mass transfer in DOC catalytic coating, while it is almost non-existent in CDPF. At low temperature, the passive regeneration of CDPF is slower than that of CRDPF, but as the temperature increases, the passive regeneration speed of CDPF will exceed that of CRDPF. CCDPF is the most effective for the NO2 catalytic formation, consumption, and efflux in the hot-start and high-speed cycle and thereby is conducive to improve the performance of the diesel particulate filter and downstream selective catalytic reduction.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Poluentes Atmosféricos/análise , Dióxido de Nitrogênio/análise , Óxidos de Nitrogênio/análise , Material Particulado/análise , Emissões de Veículos/análise
20.
Stem Cell Res Ther ; 12(1): 77, 2021 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-33482923

RESUMO

BACKGROUND: Chemotherapy is an effective anti-tumor treatment. Mesenchymal stem cells (MSCs), exerting therapy effect on injured tissues during chemotherapy, may be damaged in the process. The possibility of self-healing through long-range paracrine and the mechanisms are unclear. METHODS: Doxorubicin, a commonly used chemotherapy drug, was to treat human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) for 6 h as an in vitro cell model of chemotherapy-induced damage. Then we use extracellular vesicles derived from placental mesenchymal stem cells (hP-MSCs) to investigate the therapeutic potential of MSCs-EVs for chemotherapy injury. The mechanism was explored using microRNA sequencing. RESULTS: MSC-derived extracellular vesicles significantly alleviated the chemotherapy-induced apoptosis. Using microRNA sequencing, we identified hsa-miR-11401, which was downregulated in the Dox group but upregulated in the EV group. The upregulation of hsa-miR-11401 reduced the expression of SCOTIN, thereby inhibiting p53-dependent cell apoptosis. CONCLUSIONS: Hsa-miR-11401 expressed by MSCs can be transported to chemotherapy-damaged cells by EVs, reducing the high expression of SCOTIN in damaged cells, thereby inhibiting SCOTIN-mediated apoptosis.


Assuntos
Vesículas Extracelulares , Células-Tronco Mesenquimais , MicroRNAs , Apoptose , Doxorrubicina/farmacologia , Feminino , Humanos , MicroRNAs/genética , Placenta , Gravidez
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