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1.
Cancer Commun (Lond) ; 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32936522

RESUMO

BACKGROUND: The patterns of leukemia burden have dramatically changed in recent years. This study aimed to estimate the global trends of leukemia-related death and disability-adjusted life-years (DALYs) from 1990 to 2017. METHODS: The data was acquired from the latest version of the Global Burden of Disease (GBD) study. Estimated annual percentage changes (EAPCs) were calculated to estimate the trend of age-standardized rate (ASR) of death and DALYs due to leukemia and its main subtypes from 1990 to 2017. RESULTS: Globally, the numbers of death and DALYs due to leukemia were 347.58 × 103 (95% uncertainty interval [UI] = 317.26 × 103 -364.88 × 103 ) and 11975.35 × 103 (95% UI = 10749.15 × 103 -12793.58 × 103 ) in 2017, with a 31.22% and 0.03% increase in absolute numbers from 1990 to 2017, respectively. Both of their ASR showed decreasing trends from 1990 to 2017 with the EAPCs being -1.04 (95% confidence interval [CI] = (-1.10--0.99) and -1.52 (95% CI = -1.59--1.44), respectively. Globally, the most pronounced decreasing trend of death and DALYs occurred in chronic myeloid leukemia with EAPCs of -2.76 (95% CI = -2.88--2.64) and -2.84 (95% CI = -2.97--2.70), respectively, while the trend increased in acute myeloid leukemia. The death and DALYs of leukemia decreased in most areas and countries with high socio-demographic index (SDI) including Bahrain, Finland, and Australia. CONCLUSIONS: The disease burden of death and DALYs due to leukemia decreased globally, and for most regions and countries from 1990 to 2017. However, the leukemia burden is still a substantial challenge globally and required adequate and affordable medical resources to improve the survival and quality of life of leukemia patients.

2.
Biomater Sci ; 8(15): 4067-4072, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32648564

RESUMO

We herein explored a smart Fe-HPPy@Au/DOX theranostic agent for CT diagnosis and PTT/chemotherapy/CDT synergistic treatment of cancer. When the Fe-HPPy@Au/DOX theranostic agent entered the tumor, the tumor environment accelerated the trapped Fe ions release to catalyze the production of ˙OH for CDT. NIR irradiation drove the PTT, and at the same time improved the CDT by increasing the production of ˙OH and triggered DOX release for chemotherapy. In addition, the Au nanoparticles on the surface of Fe-HPPy@Au nanocomposites could be used as a CT imaging agent and catalyzer to produce H2O2 for enhanced CDT.

3.
Pharmacol Res ; 157: 104840, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32353589

RESUMO

Hepatocyte nuclear factor 4 alpha (HNF4α) regulates the expression of essential genes involved in very-low-density lipoprotein (VLDL) homeostasis and gluconeogenesis. 18ß-glycyrrhetinic acid (GA) is an active ingredient of Glycyrrhiza uralensis an herbal medicine used for treating liver aliments. In this study, we established that GA functions as a partial antagonist of HNF4α through HNF4α-driven reporter luciferase assay and co-immunoprecipitation experiments with co-activator PGC1α. By virtual docking and site-directed mutagenesis analysis, we confirmed that serine 190 and arginine 235 of HNF4α are both essential for GA to exert its antagonistic action on HNF4α. Importantly, GA suppressed the expression of HNF4α target genes such as apolipoprotein B (ApoB), microsomal triglyceride transfer protein (MTP) and phospholipase A2 G12B (PLA2G12B) modulating hepatic VLDL secretion in mice fed on a high fat diet. In addition, GA also suppressed gluconeogenesis and ameliorated glucose intolerance via down-regulating the expression of HNF4α target genes glucose-6-phosphatase (G6pc) and phosphoenolpyruvate carboxykinase (Pepck). Furthermore, GA significantly lowered blood glucose and improved insulin resistance in db/db mice. In all, we established that GA acts as a partial HNF4α antagonist modulating lipid and carbohydrate metabolism.

4.
Mol Cell Endocrinol ; 513: 110867, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32422400

RESUMO

Hepatic nuclear factor 4 alpha (HNF4α) drives the expression of apolipoprotein B (ApoB), microsomal triglyceride transfer protein (MTP) and phospholipase A2 G12B (PLA2G12B), governing hepatic very-low-density lipoprotein (VLDL) production and secretion. Andrographolide (AP) is a major constituent isolated from Andrographis paniculata. We found that AP can disrupt the interaction between HNF4α and its coactivator peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α). Virtual docking and mutational analysis indicated that arginine 235 of HNF4α is essential for binding to AP. As a consequence of antagonizing the activity of HNF4α, AP suppresses the expression of ApoB, MTP and PLA2G12B and reduces the rate of hepatic VLDL secretion in vivo. AP additionally reduced gluconeogenesis via down-regulating the expression of HNF4α target genes phosphoenolpyruvate carboxykinase (Pepck) and glucose-6-phosphatase (G6pc). Collectively, our results suggest that AP affects liver function via modulating the transcriptional activity of HNF4α.

5.
BMC Microbiol ; 20(1): 94, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32295529

RESUMO

BACKGROUND: Murine kobuviruses (MuKV) are newly recognized picornaviruses first detected in murine rodents in the USA in 2011. Little information on MuKV epidemiology in murine rodents is available. Therefore, we conducted a survey of the prevalence and genomic characteristics of rat kobuvirus in Guangdong, China. RESULTS: Fecal samples from 223 rats (Rattus norvegicus) were collected from Guangdong and kobuviruses were detected in 12.6% (28) of samples. Phylogenetic analysis based on partial 3D and complete VP1 sequence regions showed that rat kobuvirus obtained in this study were genetically closely related to those of rat/mouse kobuvirus reported in other geographical areas. Two near full-length rat kobuvirus genomes (MM33, GZ85) were acquired and phylogenetic analysis of these revealed that they shared very high nucleotide/amino acids identity with one another (95.4%/99.4%) and a sewage-derived sequence (86.9%/93.5% and 87.5%/93.7%, respectively). Comparison with original Aichivirus A strains, such human kobuvirus, revealed amino acid identity values of approximately 80%. CONCLUSION: Our findings indicate that rat kobuvirus have distinctive genetic characteristics from other Aichivirus A viruses. Additionally, rat kobuvirus may spread via sewage.

6.
Small ; 16(13): e1905938, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32115895

RESUMO

Nanobactericides represent one of the most efficient and promising strategies for eliminating bacterial infection considering the increasing resistance threats of conventional antibiotics. Black phosphorus (BP) is the most exciting postgraphene layered 2D nanomaterial with convincing physiochemical properties, yet the study of BP-based antibiotics is still in its infancy. Here, a compact silver nanoparticle (AgNP)-doped black phosphorus nanosheet (BPN) is constructed to synergistically enhance solar disinfection through the promoted reactive oxygen species (ROS) photogeneration, which is attributed to the improved electron-hole separation and recombination of BPNs as revealed from the systematic experimental studies. An in-depth density functional theory (DFT) calculation confirms that the integrated AgNPs provide a preferred site for facilitating the adsorption and activation of O2 , thus promoting the more efficient and robust ROS generation on BPN-AgNP nanohybrids. Besides the enhanced photoinduced ROS, the anchored AgNPs simultaneously lead to a dramatically increased affinity toward bacteria, which facilitates a synergetic pathogen inactivation. Significantly, the convincing antimicrobial BPN-AgNP contributes to the prominent wound healing and antimicrobial ability in vivo with minimized biological burden. This sophisticated design of new 2D nanohybrids opens a new avenue for further exploiting BP-based nanohybrids in portable bandage and broad-spectrum disinfection applications.

7.
Langmuir ; 36(4): 852-861, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31898907

RESUMO

Aqueous lubrication in nature is attracting increasing attention in the tribological fields for reducing friction energy consumption and improving anti-wear durability. Generally, adding nanolubricant additives is one of the most important strategies to effectively enhance the interface performance under boundary lubrication via the formation of a protective tribofilm on rubbing surfaces. However, the adsorbed tribofilms are unstable and are prone to failure during friction, and the interaction mechanism between the tribofilms and frictional interfaces is partly disclosed. In this study, inspired by mussels, an in situ-assembled polydopamine (PDA) tribofilm is achieved with PDA nanoparticles as aqueous lubricant additives, which shows excellent lubrication properties. The coefficient of friction is interface-independent and is reduced by as much as 83%. The results show that the PDA tribofilm can not only form chemical bonding with metal interfaces but also present a synergistic lubrication effect with the upper ceramic surface. Especially, a self-repairing effect of the PAD tribofilm is observed, by which the ultrastable lubricating properties can be achieved during friction, and thus, the friction and wear can be effectively controlled. This work provides an effective method for improving the interface stability of friction pairs under aqueous lubrication and also shows great meaning for industrial applications.

8.
J Bone Miner Res ; 35(2): 306-316, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31614022

RESUMO

Circulating microRNAs (miRNAs) play important roles in regulating gene expression and have been reported to be involved in various metabolic diseases, including osteoporosis. Although the transcriptional regulation of osteoblast differentiation has been well characterized, the role of circulating miRNAs in this process is poorly understood. Here we discovered that the level of circulating miR-19b was significantly lower in osteoporotic patients with vertebral compression fractures than that of healthy controls. The expression level of miR-19b was increased during osteoblastic differentiation of human mesenchymal stem cells (hMSCs) and MC3T3-E1 cells, and transfection with synthetic miR-19b could promote osteoblastic differentiation of hMSCs and MC3T3-E1 cells. PTEN (phosphatase and tensin homolog deleted from chromosome 10) was found to be directly repressed by miR-19b, with a concomitant increase in Runx2 expression and increased phosphorylation of AKT (protein kinase B, PKB). The expression level of circulating miR-19b in aged ovariectomized mice was significantly lower than in young mice. Moreover, the osteoporotic bone phenotype in aged ovariectomized mice was alleviated by the injection of chemically modified miR-19b (agomiR-19b). Taken together, our results show that circulating miR-19b plays an important role in enhancing osteoblastogenesis, possibly through regulation of the PTEN/pAKT/Runx2 pathway, and may be a useful therapeutic target in bone loss disorders, such as osteoporosis. © 2019 American Society for Bone and Mineral Research.

9.
Nano Lett ; 19(9): 6315-6322, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31441658

RESUMO

One-dimensional (1D) semiconductor nanorods are important for numerous applications ranging from optics and electronics to biology, yet the direct synthesis of high-quality metal halide perovskite nanorods remains a challenge. Here, we develop an intermediate monomer reservoir synthetic strategy to realize the controllable growth of uniform and low-defect CsPbBr3 perovskite nanorods. Intermediates composed of CsPb2Br5 and Cs3In2Br9 are obtained through the substitution of Pb2+ with In3+ cations in the template of CsPbBr3 nanocubes and act as a precursor reservoir to gradually release monomers, ensuring both the slow growth rate and low defects of nanorods. We have used branched tris(diethylamino)phosphine as a ligand, which not only has unequal binding energies with different crystal faces to promote the orientation growth but also provides strong steric hindrance to shield the nanorods in solution. Because of minor amount of defects and an effective ligand passivation, in addition to significantly enhanced stability, the perovskite nanorods show a high photoluminescence quantum yield of up to 90% and exhibit a net mode gain of 980 cm-1, the latter being a record value among all the perovskite materials. An extremely low amplified spontaneous emission threshold of 7.5 µJ cm-2 is obtained under excitation by a nanosecond laser, which is comparable to that obtained using femtosecond lasers in other recent studies.

10.
J Phys Chem Lett ; 10(12): 3465-3471, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31184156

RESUMO

Herein we employed a first-principles method based on density functional theory to investigate the surface energy and growth kinetics of wurtzite nanoplatelets to elucidate why nanoplatelets exhibit a uniform thickness of eight monolayers. We synthesized a series of wurtzite nanoplatelets (ZnSe, ZnS, ZnTe, and CdSe) with an atomically uniform thickness of eight monolayers. As a representative example, the growth mechanism of 1.39 nm thick (eight monolayers) wurtzite ZnSe nanoplatelets was studied to substantiate the proposed growth kinetics. The results show that the growth of the seventh and eighth layers along the [112̅0] direction of 0.99 nm (six monolayers) ZnSe magic-size nanoclusters is accessible, whereas the growth of the ninth layer is unlikely to occur because the formation energy is large. This work not only gives insights into the synthesis of atomically uniform thick wurtzite semiconductor nanoplatelets but also opens up new avenues to their applications in light-emitting diodes, catalysis, detectors, and lasers.

11.
Photodiagnosis Photodyn Ther ; 27: 298-304, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31185324

RESUMO

BACKGROUND: Bladder cancer is the fourth most common malignancy in men and a considerable disease burden globally. Multiple studies have focused on the accuracy of optical coherence tomography for bladder cancer diagnosis; however, the findings are inconsistent. Here, we assessed the accuracy of optical coherence tomography for bladder cancer diagnosis. METHODS: Embase, PubMed, Medline, Web of Science, and the Cochrane Library database were searched for relevant studies from the earliest date available through March 11, 2019. Studies evaluating the accuracy of optical coherence tomography bladder cancer diagnosis were included. Pooled sensitivity, specificity, and area under the curve values of weighted symmetric summary receiver operating curves, were calculated at the per-lesion level. RESULTS: Eleven studies, with a total of 1933 lesions, were included in the final analysis. The pooled results indicated that optical coherence tomography can differentiate bladder cancer from benign lesions: sensitivity, 94.9% (95% confidence interval: 92.7%-96.6%); specificity, 84.6% (95% confidence interval: 82.6%-86.4%); area under the curve, 0.97. Moreover, compared with optical coherence tomography alone, combined optical coherence tomography and fluorescence cystoscopy increased the diagnostic accuracy (sensitivity, 94.3% vs. 87.3%; specificity, 89.2% vs. 73.9%). Cross-polarization optical coherence tomography could also distinguish bladder cancer from normal tissue: sensitivity, 92.0% (95% confidence interval: 87.0%-95.6%); specificity, 84.4% (95% confidence interval: 81.7%-86.9%); area under the curve, 0.95. CONCLUSIONS: Optical coherence tomography can accurately differentiate malignant from benign bladder lesions, particularly when combined with fluorescence cystoscopy.


Assuntos
Tomografia de Coerência Óptica/métodos , Neoplasias da Bexiga Urinária/diagnóstico , Cistoscopia/métodos , Fluorescência , Humanos , Sensibilidade e Especificidade , Tomografia de Coerência Óptica/normas , Neoplasias da Bexiga Urinária/patologia
12.
J Clin Endocrinol Metab ; 104(8): 3345-3354, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30896760

RESUMO

CONTEXT: The patterns of associations between glycated Hb (HbA1c) and mortality are still unclear. OBJECTIVE: To explore the extent to which ranges of HbA1c levels are associated with the risk of mortality among participants with and without diabetes. DESIGN, SETTING, AND PATIENTS: This was a nationwide, community-based prospective cohort study. Included were 15,869 participants (median age 64 years) of the Health and Retirement Study, with available HbA1c data and without a history of cancer. Cox proportional hazards regression models were used to estimate hazard ratios with 95% CIs for mortality. RESULTS: A total of 2133 participants died during a median follow-up of 5.8 years. In participants with diabetes, those with an HbA1c level of 6.5% were at the lowest risk of all-cause mortality. When HbA1c level was <5.6% or >7.4%, the increased all-cause mortality risk became statistically significant as compared with an HbA1c level of 6.5%. As for participants without diabetes, those with an HbA1c level of 5.4% were at the lowest risk of all-cause mortality. When the HbA1c level was <5.0%, the increased all-cause mortality risk became statistically significant as compared with an HbA1c level of 5.4%. However, we did not observe a statistically significant elevated risk of all-cause mortality above an HbA1c level of 5.4%. CONCLUSIONS: A U-shaped and reverse J-shaped association for all-cause mortality was found among participants with and without diabetes. The corresponding optimal ranges for overall survival are predicted to be 5.6% and 7.4% and 5.0% and 6.5%, respectively.

13.
BMC Vet Res ; 14(1): 414, 2018 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-30577796

RESUMO

BACKGROUND: Urban rodents and house shrews are closely correlated in terms of location with humans and can transmit many pathogens to them. Hepatitis E has been confirmed to be a zoonotic disease. However, the zoonotic potential of rat HEV is still unclear. The aim of this study was to determine the prevalence and genomic characteristics of hepatitis E virus (HEV) in rodents and house shrews. RESULTS: We collected a total of 788 animals from four provinces in China. From the 614 collected murine rodents, 20.19% of the liver tissue samples and 45.76% of the fecal samples were positive for HEV. From the 174 house shrews (Suncus murinus), 5.17% fecal samples and 0.57% liver tissue samples were positive for HEV. All of the HEV sequences obtained in this study belonged to Orthohepevirus C1. However, we observed a lower percentage of identity in the ORF3 region upon comparing the amino acid sequences between Rattus norvegicus and Rattus losea. HEV derived from house shrews shared a high percentage of identity with rat HEV. Notably, the first near full-length of the HEV genome from Rattus losea is described in our study, and we also report the first near full-length rat HEV genomes in Rattus norvegicus from China. CONCLUSION: HEV is prevalent among the three common species of murine rodents (Rattus. norvegicus, Rattus. tanezumi, and Rattus. losea) in China. HEV sequences detected from house shrews were similar to rat HEV sequences. The high identity of HEV from murine rodents and house shrews suggested that HEV can spread among different animal species.


Assuntos
Genoma Viral/genética , Vírus da Hepatite E/genética , Hepatite E/epidemiologia , Hepatite E/virologia , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/virologia , Animais , China/epidemiologia , Vírus da Hepatite E/classificação , Prevalência , Ratos , Homologia de Sequência do Ácido Nucleico , Musaranhos , Zoonoses/epidemiologia , Zoonoses/virologia
14.
Intervirology ; 61(3): 143-148, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30404084

RESUMO

OBJECTIVE: To investigate the prevalence of the adeno-associated virus (AAV) in murine rodents and house shrews in 4 provinces of China. METHODS: A total of 469 murine rodents and 19 house shrews were captured between May 2015 and May 2017. Cap gene of AAV sequences was obtained to evaluate the genetic characteristics of rat AAV. RESULTS: Rat AAVs were found in 54.7% (267/488) of throat swabs, 14.3% (70/488) of fecal samples, and 18.4% (41/223) of serum samples. Rat AAVs were detected in 3 species of murine rodents including Rattus norvegicus (34.8%), R. tanezumi (43.0%), and R. losea (2.3%), and house shrews (Suncus murinus) (26.1%) from the selected sampling sites. Fourteen near-full-length Cap gene sequences, ranging in length from 2,156 to 2,169 nt, were isolated from the fecal samples of R. norvegicus and R. tanezumi. These 14 sequences shared a high identity of 97.4% at the nucleotide level and 99.1% at the amino acid level. Phylogenetic analysis showed that the rat AAV formed a distinct clade, distinguishable from the AAV discovered in humans and in other animals. CONCLUSIONS: A high prevalence of rat AAV that was highly conserved within the Cap gene was found in 3 common murine rodents and house shrews in China.


Assuntos
Portador Sadio/veterinária , Portador Sadio/virologia , Dependovirus , Infecções por Parvoviridae/veterinária , Ratos/virologia , Musaranhos/virologia , Animais , China/epidemiologia , DNA Viral/genética , Fezes/virologia , Infecções por Parvoviridae/sangue , Faringe/virologia , Filogenia , Prevalência , Roedores/virologia
15.
Arch Virol ; 163(11): 3099-3103, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30039316

RESUMO

In this study, we detected and genetically characterized rat bocavirus (RBoV) carried in 496 murine rodents that were captured in four provinces in China between May 2015 and May 2017. RBoV-positive samples were found in all four provinces, with a total positive rate of 24.8% (123/496) in throat swabs and 58.1% (286/492) in fecal samples. Twelve nearly full-length genome sequences of RBoV were determined, and the average sequence identity was 96.2%. Phylogenetic analysis showed that RBoVs formed a distinct clade that was distinguishable from the bocaviruses discovered in humans and other animals.


Assuntos
Bocavirus/isolamento & purificação , Fezes/virologia , Orofaringe/virologia , Infecções por Parvoviridae/veterinária , Doenças dos Roedores/virologia , Animais , Bocavirus/classificação , Bocavirus/genética , Genoma Viral , Infecções por Parvoviridae/virologia , Filogenia , Ratos , Roedores
16.
Dalton Trans ; 47(7): 2460-2469, 2018 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-29383347

RESUMO

The mechanism of the ruthenium carboxylate-catalyzed hydrogenation of carboxylic acids was investigated by using density functional theory (DFT) calculations. The novel mechanism including two hydrogenation cycles was proposed for this reaction. The first cycle is the hydrogenation of the carboxylic acid to an aldehyde, while the second cycle is the hydrogenation of the aldehyde to an alcohol. These two catalytic cycles share similar elementary steps, including H2 heterolysis, hydride migration of the carboxylic acid or aldehyde, and catalyst regeneration. In this hydrogenation mechanism, the carboxylic acid is not only a reactant, but also an important proton source. Furthermore, the noncovalent interaction (e.g. hydrogen bonding interaction) between the ligand and carboxylic acid substrate could promote the hydrogenation of the carboxylic acid through stabilizing the transition state of the most energy-demanding step (i.e., hydride migration in the first catalytic cycle). Besides, the strong electron-donating ability of the dppb ligand could also facilitate the hydride migration.

17.
ACS Appl Mater Interfaces ; 9(30): 25350-25357, 2017 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-28686008

RESUMO

The solid oxide CO2 electrolyzer has the potential to provide storage solutions for intermittent renewable energy sources as well as to reduce greenhouse gas emissions. One of the key challenges remains the poor adsorption and activity toward CO2 reduction on the electrolyzer cathode at typical operating conditions. Here, we show a novel approach in tailoring a perovskite titanate (La, Sr)TiO3+δ cathode surface, by the in situ growing of SrO nanoislands from the host material through the control of perovskite nonstoichiometry. These nanoislands provide very enhanced CO2 adsorption and activation, with stability up to 800 °C, which is shown to be in an intermediate form between carbonate ions and molecular CO2. The activation of adsorbed CO2 molecules results from the interaction of exsolved SrO nanoislands and the defected titanate surface as revealed by DFT calculations. These cathode surface modifications result in an exceptionally high direct CO2 electrolysis performance with current efficiencies near 100%.

18.
Nat Commun ; 8: 14785, 2017 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-28300066

RESUMO

Sustainable future energy scenarios require significant efficiency improvements in both electricity generation and storage. High-temperature solid oxide cells, and in particular carbon dioxide electrolysers, afford chemical storage of available electricity that can both stabilize and extend the utilization of renewables. Here we present a double doping strategy to facilitate CO2 reduction at perovskite titanate cathode surfaces, promoting adsorption/activation by making use of redox active dopants such as Mn linked to oxygen vacancies and dopants such as Ni that afford metal nanoparticle exsolution. Combined experimental characterization and first-principle calculations reveal that the adsorbed and activated CO2 adopts an intermediate chemical state between a carbon dioxide molecule and a carbonate ion. The dual doping strategy provides optimal performance with no degradation being observed after 100 h of high-temperature operation and 10 redox cycles, suggesting a reliable cathode material for CO2 electrolysis.

19.
Springerplus ; 5(1): 1942, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27933232

RESUMO

BACKGROUND: Dengue is one of the most important emerging diseases of humans, with no preventive vaccines or antiviral cures available currently. In 2014, the Southeast Asian region experienced an unprecedented outbreak of dengue, especially in Guangdong, China. RESULTS: The nucleotide sequences of the E gene from 23 patients sera of dengue virus type 1 (DENV-1) from Guangzhou, China, were determined. One isolate that was recovered from a patient with serious liver damage was designated GZ02. The whole genome sequence of GZ02 was amplified, and confocal microscopy and plaque reduction neutralization test were performed to investigate the replication kinetics in liver L02 cells. In the study, assembly and genetic comparisons showed 11 of those E gene nucleotide sequences were absolutely accordant, and the nucleic acid sequence divergence among the other strains had no marked difference. CONCLUSIONS: Phylogenetic analysis based on the E gene indicated that the 23 new strains were closely related to strains from Malaysia or Singapore. Two different genotypes (genotype I and III) of DENV-1 were co-circulating in Guangdong, Malaysia, and Singapore from 2013 to 2014. However, no recombination event was found after 2005 between DENV strains from Guangdong and Malaysia or Singapore. GZ02 had a significant replicative advantage over DG14 and the DV1 standard strain. Importation of DENV-1 from Southeast Asian countries may have been an important contributing factor to the 2014 outbreak in Guangdong.

20.
Org Biomol Chem ; 11(8): 1414-22, 2013 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-23338242

RESUMO

The excited-state proton transfer (ESPT) via proton transfer wires in green fluorescent protein (GFP) plays an important role on the spectroscopic of GFP. In this work, we use the proton transfer wires and the chromophore complex to simulate the tautomer structures of neutral state and the intermediate state in wt-GFP. And we employ the time-dependent density functional theory combined with the sum-over-states method to calculate the one- and two-photon absorption properties of these complexes in GFP. We obtain the large stokes shift from 383 nm to 500 nm in GFP when simulating the ESPT process by these isomerous H-bonding complexes. We find that the TPA spectrum of the H-bonding complex of the intermediate state agrees more with experimental measurement than that of the H-bonding complex of the neutral state. The TPA spectrum of GFP might be mainly dominated by the structure which is similar to the H-bonding complex of intermediate state. Further, we simulate another kind of complex which possess short-strong hydrogen bonds in proton transfer wires, and find that TPA properties of these complexes are much stronger than that of the complexes with the long distance proton wires from GFP.


Assuntos
Proteínas de Fluorescência Verde/química , Prótons , Teoria Quântica , Absorção
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