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1.
Artículo en Inglés | MEDLINE | ID: mdl-38905097

RESUMEN

The detection head constitutes a pivotal component within object detectors, tasked with executing both classification and localization functions. Regrettably, the commonly used parallel head often lacks omni perceptual capabilities, such as deformation perception (DP), global perception (GP), and cross-task perception (CTP). Despite numerous methods attempting to enhance these abilities from a single aspect, achieving a comprehensive and unified solution remains a significant challenge. In response to this challenge, we develop an innovative detection head, termed UniHead, to unify three perceptual abilities simultaneously. More precisely, our approach: 1) introduces DP, enabling the model to adaptively sample object features; 2) proposes a dual-axial aggregation transformer (DAT) to adeptly model long-range dependencies, thereby achieving GP; and 3) devises a cross-task interaction transformer (CIT) that facilitates interaction between the classification and localization branches, thus aligning the two tasks. As a plug-and-play method, the proposed UniHead can be conveniently integrated with existing detectors. Extensive experiments on the COCO dataset demonstrate that our UniHead can bring significant improvements to many detectors. For instance, the UniHead can obtain + 2.7 AP gains in RetinaNet, + 2.9 AP gains in FreeAnchor, and + 2.1 AP gains in GFL. The code is available at https://github.com/zht8506/UniHead.

2.
Ophthalmologica ; 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38889695

RESUMEN

INTRODUCTION: To compare the long-term outcomes of conventional scleral buckling (CSB), modified scleral buckling (MSB), and scleral encircling (SE) in the treatment of rhegmatogenous retinal detachment and identify factors influencing the outcomes. METHODS: This comparative, retrospective cohort study assigned patients to CSB, MSB, and SE groups. The follow-up was 12 months, and the reattachment rate, complication rate, visual acuity, number of newly discovered tears during surgery, and changes in diopters were compared among the three surgeries. Influential factors on anatomical and functional reattachment were identified. RESULTS: There were no significant differences in the primary reattachment rate, overall complication rate, or best-corrected visual acuity at 6 or 12 months among the three groups. The MSB group had a higher number of newly discovered tears during surgery compared with the other two groups. At 12 months post-surgery, the SE group displayed the greatest change of diopter, whereas the MSB group showed the least change. The surgical approach did not influence the primary reattachment rate. Long-term visual outcomes were influenced by factors including sex, preoperative visual acuity, macular status, and duration of symptoms. CONCLUSION: MSB is an effective method for treating rhegmatogenous retinal detachment. Its advantages include the ability to identify smaller tears and induce minimal changes in diopter.

3.
Int J Mol Sci ; 25(12)2024 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-38928505

RESUMEN

Nannochloropsis gaditana, a microalga known for its photosynthetic efficiency, serves as a cell factory, producing valuable biomolecules such as proteins, lipids, and pigments. These components make it an ideal candidate for biofuel production and pharmaceutical applications. In this study, we genetically engineered N. gaditana to overexpress the enzyme fructose-1,6-bisphosphatase (cyFBPase) using the Hsp promoter, aiming to enhance sugar metabolism and biomass accumulation. The modified algal strain, termed NgFBP, exhibited a 1.34-fold increase in cyFBPase activity under photoautotrophic conditions. This modification led to a doubling of biomass production and an increase in eicosapentaenoic acid (EPA) content in fatty acids to 20.78-23.08%. Additionally, the genetic alteration activated the pathways related to glycine, protoporphyrin, thioglucosides, pantothenic acid, CoA, and glycerophospholipids. This shift in carbon allocation towards chloroplast development significantly enhanced photosynthesis and growth. The outcomes of this study not only improve our understanding of photosynthesis and carbon allocation in N. gaditana but also suggest new biotechnological methods to optimize biomass yield and compound production in microalgae.


Asunto(s)
Biomasa , Fructosa-Bifosfatasa , Metabolómica , Microalgas , Fotosíntesis , Estramenopilos , Fructosa-Bifosfatasa/metabolismo , Fructosa-Bifosfatasa/genética , Estramenopilos/genética , Estramenopilos/metabolismo , Estramenopilos/crecimiento & desarrollo , Estramenopilos/enzimología , Microalgas/metabolismo , Microalgas/genética , Microalgas/crecimiento & desarrollo , Microalgas/enzimología , Metabolómica/métodos , Citosol/metabolismo
4.
PLoS One ; 19(3): e0295983, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38451955

RESUMEN

BACKGROUND: Current treatment recommendations for resectable or borderline pancreatic carcinoma support upfront surgery and adjuvant therapy. However, neoadjuvant therapy (NT) seems to increase prognosis of pancreatic carcinoma and come to everyone's attention gradually. Randomized controlled trials offering comparison with the NT are lacking and optimal neoadjuvant treatment regimen still remains uncertain. This study aims to compare both treatment strategies for resectable or borderline resectable pancreatic cancer. METHODS: The PRISMA checklist was used as a guide to systematically review relevant peer-reviewed literature reporting primary data analysis. We searched PubMed, Medline, EMBASE, Cochrane Datebase and related reviews for randomized controlled trials comparing neoadjuvant therapy with surgery first for resectable or borderline resectable pancreatic carcinoma. We estimated relative hazard ratios (HRs) for median overall survival and ratios risks (RRs) for microscopically complete (R0) resection among different neoadjuvant regimens and major complications. We assessed the effects of neoadjuvant therapy on R0 resection rate and median overall survival with Bayesian analysis. RESULTS: Thirteen eligible articles were included. Eight studies performed comparison neoadjuvant therapy with surgery first, and R0 resection rate was recorded in seven studies. Compared with surgery first, neoadjuvant therapy did increase the R0 resection rate (RR = 1.53, I2 = 0%, P< 0.00001), there was a certain possibility that gemcitabine + cisplatin (Gem+Cis) + Radiotherapy was the most favorable in terms of the fact that there was no significant difference concerning the results from the individual studies. In direct comparison, four studies were included and estimated that Neoadjuvant therapy improved mOS compared with upfront surgery (HR 0.68, 95% CI 0.58-0.92; P = 0.012; I2 = 15%), after Bayesian analysis it seemed that regimen with Cisplatin/ Epirubicin then Gemcitabine/ Capecitabine (PEXG) was most likely the best with a relatively small sample size. The rate of major surgical complications was available for six studies and ranged from 11% to 56% with neoadjuvant therapy and 11% to 45% with surgery first. There was no significant difference between neoadjuvant therapy and surgery first, also with a high heterogeneity (RR = 0.96, 95%CI = 0.65-1.43; P = 0.85; I2 = 46%). CONCLUSION: In conclusion neoadjuvant therapy might offer benefit over up-front surgery. Neoadjuvant therapy increased the R0 resection rate with gemcitabine + cisplatin + Radiotherapy that was the most favorable and improved mOS with Cisplatin/ Epirubicin then Gemcitabine/ Capecitabine (PEXG) that was most likely the best.


Asunto(s)
Terapia Neoadyuvante , Neoplasias Pancreáticas , Humanos , Terapia Neoadyuvante/métodos , Gemcitabina , Capecitabina/uso terapéutico , Cisplatino/uso terapéutico , Epirrubicina/uso terapéutico , Metaanálisis en Red , Teorema de Bayes , Ensayos Clínicos Controlados Aleatorios como Asunto , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/cirugía , Desoxicitidina/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica
5.
Int J Mol Sci ; 24(17)2023 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-37686401

RESUMEN

The cell cycle is the fundamental cellular process of eukaryotes. Although cell-cycle-related genes have been identified in microalgae, their cell cycle progression differs from species to species. Cell enlargement in microalgae is an essential biological trait. At the same time, there are various causes of cell enlargement, such as environmental factors, especially gene mutations. In this study, we first determined the phenotypic and biochemical characteristics of a previously obtained enlarged-cell-size mutant of Nannochloropsis oceanica, which was designated ECS. Whole-genome sequencing analysis of the insertion sites of ECS indicated that the insertion fragment is integrated inside the 5'-UTR of U/P-type cyclin CYCU;1 and significantly decreases the gene expression of this cyclin. In addition, the transcriptome showed that CYCU;1 is a highly expressed cyclin. Furthermore, cell cycle analysis and RT-qPCR of cell-cycle-related genes showed that ECS maintains a high proportion of 4C cells and a low proportion of 1C cells, and the expression level of CYCU;1 in wild-type (WT) cells is significantly increased at the end of the light phase and the beginning of the dark phase. This means that CYCU;1 is involved in cell division in the dark phase. Our results explain the reason for the larger ECS size. Mutation of CYCU;1 leads to the failure of ECS to fully complete cell division in the dark phase, resulting in an enlargement of the cell size and a decrease in cell density, which is helpful to understand the function of CYCU;1 in the Nannochloropsis cell cycle.


Asunto(s)
Ciclinas , Microalgas , Humanos , Hipertrofia , Tamaño de la Célula , Aumento de la Célula , División Celular , Regiones no Traducidas 5' , Microalgas/genética
6.
Nat Mater ; 22(9): 1152-1159, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37500960

RESUMEN

Photomechanical crystals composed of three-dimensionally ordered and densely packed photochromes hold promise for high-performance photochemical actuators. However, bulk crystals with high structural ordering are severely limited in their flexibility, resulting in poor processibility and a tendency to fragment upon light exposure, while previous nano- or microcrystalline composites have lacked global alignment. Here we demonstrate a photon-fuelled macroscopic actuator consisting of diarylethene microcrystals in a polyethylene terephthalate host matrix. These microcrystals survive large deformations and show a high degree of three-dimensional ordering dictated by the anisotropic polyethylene terephthalate, which critically also has a similar stiffness. Overall, these ordered and compliant composites exhibit rapid response times, sustain a performance of over at least hundreds of cycles and generate work densities exceeding those of single crystals. Our composites represent the state-of-the-art for photochemical actuators and enable properties unattainable by single crystals, such as controllable, reversible and abrupt jumping (photosalient behaviour).

7.
Artículo en Inglés | MEDLINE | ID: mdl-35451950

RESUMEN

A rod-shaped, Gram-stain-negative, aerobic and non-motile bacterium, designated strain Y4T, was isolated from an aquaculture farm in Xiamen, PR China. Strain Y4T had 94.8, 93.3 and 91.8 % 16S rRNA gene sequence similarity to Paremcibacter congregatus ZYLT, Emcibacter nanhaiensis HTCJW17T and Luteithermobacter gelatinilyticus MEBiC09520T, respectively. The genomic DNA G+C content of strain Y4T was 42.7 mol%. The average amino acid identity and percentage of conserved proteins values between strain Y4T and type strains of the family Emcibacteraceae were 57.9-58.6 % and 44.5-47.6 %, respectively. Optimal growth was observed at 28 °C, at pH 7.0 and with 2 % (w/v) NaCl. The novel strain Y4T required Ca2+, K+ and Mg2+ ions in addition to NaCl for growth. The dominant fatty acids of strain Y4T were summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c) and C14 : 0 2-OH. The polar lipid profile contained phosphatidylethanolamine, phosphatidyglycerol, three unidentified aminolipids, four unidentified aminophospholipids and two unidentified lipids. Cells contained exclusively ubiquinone Q-10. On the basis of the polyphasic analysis, strain Y4T (=MCCC 1K06278T=KCTC 82926T) is considered to represent a novel species in a novel genus of the family Emcibacteraceae, for which the name Pseudemcibacter aquimaris gen. nov., sp. nov. is proposed.


Asunto(s)
Ácidos Grasos , Cloruro de Sodio , Acuicultura , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/química , Fosfolípidos/química , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Ubiquinona/química
8.
Int J Mol Sci ; 23(7)2022 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-35409427

RESUMEN

Microalgae are considered a promising source for biodiesel. The addition of plant hormone can exert a significant impact on the production of microalgae biomass and lipid accumulation. Nevertheless, the response of microalgae cells to hormones is species- or strain-dependent. It remains controversial which genes involved in strong increase of fatty acids production in response to abscisic acid (ABA) in Chlorella sp. FACHB-8 strain. We investigated cell growth, lipid accumulation, and fatty acid composition when ABA and indol-3-acetic acid (IAA) were used in the growth medium of Chlorella sp. FACHB-8. The four treatments, including 5 mg/L IAA (E1), 10 mg/L IAA (E2), 10 mg/L ABA (E3), the combination of 5 mg/L IAA and 5 mg/L ABA (E4), were found to increase cell growth, but only 10 mg/L ABA treatment could enhance the lipid accumulation. The fatty acid profile was changed by the addition of ABA, making fatty acids afflux from polyunsaturated fatty acids to monounsaturated and saturated fatty acids, which were suitable for diesel application. Furthermore, a transcriptome analysis was conducted, unraveling the differentially expressed genes enriched in fatty acid biosynthesis, fatty acid metabolism, and biosynthesis of the unsaturated fatty acid pathway in response to ABA. Our results clarified the correlation of fatty acid synthesis-related genes and fatty acid profiles, helping understand the potential response mechanism of Chlorella sp. FACHB-8 strain respond to ABA treatment.


Asunto(s)
Chlorella , Microalgas , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacología , Ácido Acético/metabolismo , Biocombustibles , Biomasa , Chlorella/metabolismo , Ácidos Grasos/metabolismo , Ácidos Grasos Insaturados/metabolismo , Microalgas/metabolismo
9.
Toxins (Basel) ; 13(5)2021 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-34064406

RESUMEN

Ribosome-inactivating proteins (RIPs) are toxic proteins that can inhibit protein synthesis. RIPs purified from Bougainvillea have low nonspecific toxicity, showing promise for processing applications in the agricultural and medical fields. However, systematic research on the polymorphism of Bougainvillea RIPs is lacking, and it is worth exploring whether different isoforms differ in their active characteristics. The transcriptional and translational expression of type I RIPs in Bougainvillea glabra leaves was investigated in this study. Seven RIPs exhibited seasonal variation at both the mRNA and protein levels. The isoforms BI4 and BI6 showed the highest transcriptional expression in both the summer and autumn samples. Interestingly, BI6 was not detected in the protein level in any of the samples. However, the bioinformatics analysis showed that RIPs derived from the same species were gathered in a different cluster, and that the active sites changed among the isoforms during evolution. The significant discrepancy in Bougainvillea RIPs mainly locates at both termini of the amino acid sequence, particularly at the C terminus. Post-translational modifications may also exist in Bougainvillea RIPs. It is concluded that the reason for the polymorphism of Bougainvillea RIPs may be that these proteins are encoded by multiple genes due to genetic processes such as gene duplication and mutation. According to the results of sequence analysis, the possible functional differences of B. glabra RIP isoforms are discussed with regard to the observed discrepancy in both active sites and structures.


Asunto(s)
Nyctaginaceae/metabolismo , Proteínas de Plantas/genética , Proteínas Inactivadoras de Ribosomas/genética , Secuencia de Aminoácidos , Dominio Catalítico , Nyctaginaceae/genética , Hojas de la Planta , Polimorfismo Genético , Biosíntesis de Proteínas
10.
Int J Syst Evol Microbiol ; 70(12): 6220-6225, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33054905

RESUMEN

A novel Gram-stain-negative, rod-shaped, aerobic, oxidase-positive and catalase-positive bacterium of the genus Pseudooceanicola, designated strain E2-1T, was isolated from surface water of Jiulong River Estuary, PR China. Cells of strain E2-1T grew in medium containing 0.5-12 % NaCl (w/v; optimum, 2-4 %), at 15-45 °C (optimum, 28-33 °C) and at pH 7.0-9.0 (optimum, pH 7.0-8.0). Comparative analyses of the 16S rRNA gene sequence revealed that strain E2-1T had the highest similarity to Pseudooceanicola nitratireducens JLT1210T (97.3 %) and Pseudooceanicola batsensis HTCC2597T (97.1 %), and had less than 97.0 % 16S rRNA gene sequence similarity to other type strains within the genus Pseudooceanicola. The DNA G+C content of strain E2-1T was 65.7 mol%. The average nucleotide identity and digital DNA-DNA hybridization relatedness values between E2-1T and related type strains were 75.0 and 20.1 % with P. nitratireducens JLT1210T and 75.6 and 20.4 % with P. batsensis HTCC2597T, respectively. The sole isoprenoid quinone was Q-10; the predominant polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, three unidentified phospholipids and six unidentified lipids; the major cellular fatty acids were C16 : 0 (17.5 %), C19 : 0 cyclo ω8c (22.7 %) and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c; 10.1 %). According to the phylogenetic and genotypic results, strain E2-1T represents a novel species in the genus Pseudooceanicola, for which the name Pseudooceanicola aestuarii sp. nov. is proposed. The type strain is E2-1T (=MCCC 1K03742T=KCTC 72107T).


Asunto(s)
Estuarios , Filogenia , Rhodobacteraceae/clasificación , Ríos/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , China , ADN Bacteriano/genética , Ácidos Grasos/química , Hibridación de Ácido Nucleico , Fosfolípidos/química , ARN Ribosómico 16S/genética , Rhodobacteraceae/aislamiento & purificación , Análisis de Secuencia de ADN , Ubiquinona/análogos & derivados , Ubiquinona/química
11.
ACS Macro Lett ; 9(8): 1172-1177, 2020 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-32864191

RESUMEN

Photoinduced shape morphing has implications in fields ranging from soft robotics to biomedical devices. Despite considerable effort in this area, it remains a challenge to design materials that can be both rapidly deployed and reconfigured into multiple different three-dimensional forms, particularly in aqueous environments. In this work, we present a simple method to program and rewrite spatial variations in swelling and, therefore, Gaussian curvature in thin sheets of hydrogels using photoswitchable supramolecular complexation of azobenzene pendent groups with dissolved α-cyclodextrin. We show that the extent of swelling can be programmed via the proportion of azobenzene isomers, with a 60% decrease in areal swelling from the all trans to the predominantly cis state near room temperature. The use of thin gel sheets provides fast response times in the range of a few tens of seconds, while the shape change is persistent in the absence of light thanks to the slow rate of thermal cis-trans isomerization. Finally, we demonstrate that a single gel sheet can be programmed with a first swelling pattern via spatially defined illumination with ultraviolet light, then erased with white light, and finally redeployed with a different swelling pattern.

12.
ACS Appl Mater Interfaces ; 12(15): 17929-17935, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32176477

RESUMEN

Fiber-shaped soft constructs are indispensable building blocks for various 3D functional objects such as hierarchical structures within the human body. The design and fabrication of such hierarchically structured soft materials, however, are often challenged by the trade-offs between stiffness, toughness, and continuous production. Here, we describe a microfluidic platform to continuously fabricate double network hydrogel microfibers with tunable structural, chemical, and mechanical features. Construction of the double network microfibers is accomplished through the incorporation of dynamic cucurbit[n]uril host-guest interactions, as energy dissipation moieties, within an agar-based brittle network. These microfibers exhibit an increase in fracture stress, stretchability, and toughness by 2-3 orders of magnitude compared to the pristine agar network, while simultaneously gaining recoverable hysteretic energy dissipation without sacrificing mechanical strength. This strategy of integrating a wide range of dynamic interactions with the breadth of natural resources could be used in the preparation of functional hydrogels, providing a versatile approach toward the continuous fabrication of soft materials with programmable functions.

13.
Front Neurosci ; 12: 817, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30459550

RESUMEN

Brain-behavior correlations are commonly used to explore the associations between the brain and human behavior in cognitive neuroscience studies. There are many critics of the correlation approach, however. Most problems associated with correlation approaches originate in the weak statistical power of traditional correlation procedures (i.e., the mean-wise interindividual brain-behavior correlation). This paper proposes a new correlation procedure, the item-wise interindividual brain-behavior correlation, which enhances statistical power via testing the significance of small correlation coefficients from trials against zero rather than simply pursuing the highest correlation coefficient. The item-wise and mean-wise correlation were compared in simulations and an fMRI experiment on mathematical problem-solving. Simulations show that the item-wise correlation relative to the mean-wise correlation results in higher t-values when signal-to-noise ratio is equal to or larger than 6%. Item-wise correlation displayed more voxels with significant brain-behavior correlation than did mean-wise correlation. Analyses with item-wise (rather than mean-wise) correlation showed significant brain-behavior correlation at the threshold of p < 0.05 corrected. Cross validation showed that odd- and even-ordered trials have greater stability in terms of the item-wise correlation (r = 0.918) than the mean-wise correlation (r = 0.686). The simulations and example analyses altogether demonstrate the effectiveness of the proposed correlation procedure for task neuroimaging studies.

14.
Zootaxa ; 4013(3): 435-9, 2015 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-26623907

RESUMEN

Amusurgus (Usgmona) excavatus Liu, Shi et Zhou, sp. nov. (China, Fujian) is described and illustrated with the male genitalia. Photos of habitus and ecological habitat are also included.


Asunto(s)
Gryllidae/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , China , Ecosistema , Femenino , Gryllidae/anatomía & histología , Gryllidae/crecimiento & desarrollo , Masculino , Tamaño de los Órganos
15.
Int J Biol Macromol ; 81: 1012-8, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26385504

RESUMEN

Thermal inactivation kinetics of Hypocrea orientalis ß-glucosidase and effect of glucose on thermostability of the enzyme have been determined in this paper. Kinetic studies showed that the thermal inactivation was irreversible and first-order reaction. The microscopic rate constants for inactivation of free enzyme and substrate-enzyme complex were both determined, which suggested that substrates can protect ß-glucosidase against thermal deactivation effectively. On the other hand, glucose was found to protect ß-glucosidase from heat inactivation to remain almost whole activity below 70°C at 20mM concentration, whereas the apparent inactivation rate of BG decreased to be 0.3×10(-3)s(-1) in the presence of 5mM glucose, smaller than that of sugar-free enzyme (1.91×10(-3)s(-1)). The intrinsic fluorescence spectra results showed that glucose also had stabilizing effect on the conformation of BG against thermal denaturation. Docking simulation depicted the interaction mode between glucose and active residues of the enzyme to produce stabilizing effect.


Asunto(s)
Glucosa/farmacología , Calor , Hypocrea/enzimología , beta-Glucosidasa/metabolismo , Alcoholes Bencílicos/farmacología , Celobiosa/farmacología , Estabilidad de Enzimas/efectos de los fármacos , Glucósidos/farmacología , Hidrólisis , Hypocrea/efectos de los fármacos , Cinética , Simulación del Acoplamiento Molecular , Espectrometría de Fluorescencia
16.
J Biosci Bioeng ; 119(3): 275-9, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25441446

RESUMEN

Tyrosinase (EC 1.14.18.1) is the key enzyme of melanin synthesis and fruit-vegetable browning. The inhibition of benzylideneacetone, benzylacetone, and 4-phenyl-2-butanol on mushroom tyrosinase was first investigated. The results shown that these three compounds could effectively inhibit the enzyme activity sharply and the inhibitory effects were determined to be reversible. Their inhibitor concentrations leading to 50% activity lost values were determined to be 1.5, 2.8, and 1.1 mM for monophenolase and 2.0, 0.6, and 0.8 mM for diphenolase, respectively. For the monophenolase activity, all of these three compounds were mixed-type inhibitors, however, only 4-phenyl-2-butanol obviously lengthened the lag time. For the diphenolase activity, benzylideneacetone and benzylacetone were mixed-type inhibitors, while 4-phenyl-2-butanol was a noncompetitive type inhibitor. In conclusion, these compounds exhibited potent antityrosinase activities. This research would provide scientific evidence for the use of benzylideneacetone, benzylacetone, and 4-phenyl-2-butanol as antityrosinase agents.


Asunto(s)
Acetona/análogos & derivados , Agaricales/enzimología , Butanoles/farmacología , Butanonas/farmacología , Inhibidores Enzimáticos/farmacología , Monofenol Monooxigenasa/antagonistas & inhibidores , Acetona/farmacología , Aditivos Alimentarios/farmacología , Cinética , Levodopa/metabolismo , Monofenol Monooxigenasa/metabolismo , Oxidación-Reducción/efectos de los fármacos , Oxidorreductasas/antagonistas & inhibidores , Oxidorreductasas/metabolismo
17.
J Biosci Bioeng ; 118(5): 583-7, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24863181

RESUMEN

In the present study the structure of proanthocyanidins from Polyalthia longifolia leaves was characterized with (13)C nuclear magnetic resonance, high performance liquid chromatography electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses. The results showed that the proanthocyanidins were mixture of homopolymers of B-type procyanidins with degree of polymerization up to 14-mer. Furthermore, the antioxidant activity of the proanthocyanidins was studied through 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free-radical scavenging activities, and ferric reducing/antioxidant power assays. In addition, antityrosinase activity of the proanthocyanidins was investigated. The IC50 for 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free-radical scavenging activity of the proanthocyanidins were 89.32 ± 12.07 and 76.79 ± 5.88 µg/mL, respectively; the ferric reducing/antioxidant power value was 710.54 ± 142.82 mg ascorbic acid equivalent/g dry weight. The IC50 for antityrosinase activity was 773.09 ± 1.47 µg/mL. In conclusion, the proanthocyanidins from P. longifolia leaves exhibited potent antioxidant and antityrosinase activities. This research would provide scientific evidence for the use of proanthocyanidins from P. longifolia leaves as antioxidant and antityrosinase agents.


Asunto(s)
Antioxidantes/aislamiento & purificación , Inhibidores Enzimáticos/aislamiento & purificación , Monofenol Monooxigenasa/antagonistas & inhibidores , Hojas de la Planta/química , Polyalthia/química , Proantocianidinas/aislamiento & purificación , Proantocianidinas/farmacología , Antioxidantes/química , Ácido Ascórbico/química , Benzotiazoles/química , Biflavonoides/química , Biflavonoides/aislamiento & purificación , Compuestos de Bifenilo/química , Compuestos de Bifenilo/aislamiento & purificación , Catequina/química , Catequina/aislamiento & purificación , Cromatografía Líquida de Alta Presión , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Depuradores de Radicales Libres/química , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética , Oxidación-Reducción , Picratos/química , Picratos/aislamiento & purificación , Proantocianidinas/química , Sustancias Reductoras/química , Espectrometría de Masa por Ionización de Electrospray , Ácidos Sulfónicos/química
18.
J Agric Food Chem ; 62(1): 123-9, 2014 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-24313351

RESUMEN

Proanthocyanidins were isolated from fruit stone of Chinese hawthorn (Crataegus pinnatifida Bge. var. major N.E.Br.). Their structures were analyzed and elucidated by methods of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and high performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI-MS). The results demonstrated that these compounds are complicated mixtures of homo- and heteropolymers consisting of procyanidin/procyanidin gallate and prodelphinidin. They possessed structural heterogeneity in monomer units, polymer length, and interflavan linkage (A-type and B-type). Their antityrosinase and antioxidant activity were then investigated. The results revealed that they can inhibit tyrosinase activities, including the monophenolase activity and the diphenolase activity. In addition, proanthocyanidins possessed potent antioxidant activity. Our studies revealed that proanthocyanidins isolated from fruit stone of Chinese hawthorn may be applied in food, agriculture, pharmaceutical, and cosmetic industries.


Asunto(s)
Antioxidantes/química , Crataegus/química , Inhibidores Enzimáticos/química , Monofenol Monooxigenasa/antagonistas & inhibidores , Extractos Vegetales/química , Proantocianidinas/química , Antioxidantes/aislamiento & purificación , Inhibidores Enzimáticos/aislamiento & purificación , Frutas/química , Estructura Molecular , Extractos Vegetales/aislamiento & purificación , Proantocianidinas/aislamiento & purificación
19.
J Zhejiang Univ Sci B ; 14(10): 903-15, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24101207

RESUMEN

In this research, the conditions for extraction of phenolics from leaves of Ficus virens were optimized using response surface methodology (RSM). The extraction abilities of phenolics (EAP) and flavonoids (EAF), the 2,2-diphenyl-1-pierylhydrazyl (DPPH) free-radical scavenging potential, and the ferric reducing/antioxidant power (FRAP) were used as quality indicators. The results of single-factor experiments showed that temperature, ethanol concentration, extraction time, and the number of extraction cycles were the main influencing variables, and these provided key information for the central composite design. The results of RSM fitted well to a second degree polynomial model and more than 98% of the variability was explained. The ideal extraction conditions for EAP, EAF, DPPH free-radical scavenging potential, and FRAP were obtained. Considering the four quality indicators overall, the ideal extraction conditions were 58% ethanol at 57 °C for 37 min with three extraction cycles. At the ideal extraction conditions, the values of EAP, EAF, DPPH free-radical scavenging potential, and FRAP were 5.72%, 3.09%, 58.88 mg ascorbic acid equivalent (AAE)/g dry weight (DW), and 15.86 mg AAE/g DW, respectively. In addition, linear correlations were observed between EAP, EAF, and antioxidant potential.


Asunto(s)
Ficus/química , Fenoles/química , Fenoles/aislamiento & purificación , Extractos Vegetales/química , Hojas de la Planta/química , Antioxidantes/química , Compuestos de Bifenilo/química , Técnicas de Química Analítica , Etanol/química , Flavonoides/química , Depuradores de Radicales Libres/química , Modelos Teóricos , Estrés Oxidativo , Picratos/química , Solventes/química , Temperatura , Factores de Tiempo
20.
Int J Biol Macromol ; 57: 151-5, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23466497

RESUMEN

The inhibitory kinetics of furfuryl alcohol, furfural and furoic acid on mushroom tyrosinase have been investigated. The results showed that these furan compounds were reversible inhibitors of the enzyme. Furthermore, furfuryl alcohol and furfural were found to be mixed-type inhibitors while furoic acid is uncompetitive inhibitor. The inhibition constants have been confirmed and the order of the inhibiting ability was furfural>furoic acid>furfuryl alcohol. They indicate that the functional groups on the furan ring play a crucial role in the inhibition on the enzyme. In addition, it was also found that these furan compounds could inhibit the proliferation of Salmonella bacteria and Bacillus subtilis to different extents. The minimum inhibitory concentration (MIC) values of furfuryl alcohol, furfural and furoic acid against B. subtilis and S. bacteria were 0.115, 0.027, 0.015 and 0.115, 0.029, 0.009 µM, respectively. The minimum bactericidal concentration (MBC) values of that were 0.115, 0.027, 0.015 and 0.231, 0.121, 0.030 µM, respectively.


Asunto(s)
Antiinfecciosos/farmacología , Bacillus subtilis/crecimiento & desarrollo , Inhibidores Enzimáticos/farmacología , Proteínas Fúngicas/antagonistas & inhibidores , Furaldehído/farmacología , Furanos/farmacología , Monofenol Monooxigenasa/antagonistas & inhibidores , Salmonella/crecimiento & desarrollo , Antiinfecciosos/química , Inhibidores Enzimáticos/química , Proteínas Fúngicas/química , Furaldehído/química , Furanos/química , Monofenol Monooxigenasa/química
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