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1.
Biosens Bioelectron ; 260: 116455, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-38824702

RESUMO

In this work, a potential-controlled electrochromic visual biosensor was developed for detecting zearalenone (ZEN) using a distance readout strategy. The sensor chip includes a square detection area and a folded signal output area created with laser etching technology. The detection area is modified with graphene oxide and ZEN aptamer, while Prussian blue (PB) is electrodeposited onto the signal output channel. When an appropriate voltage is applied, PB in the signal output area is reduced to colorless Prussian white (PW). The target ZEN molecules have the capability to release aptamers from graphene oxide (GO) surface in the detection area, resulting in a subsequent change in the potential of the visual signal output channel. This change determines the length of the channel that changes from blue to colorless, with the color change distance being proportional to the ZEN concentration. Using this distance readout strategy, ZEN detection within the range of 1 ng/mL to 300 ng/mL was achieved, with a detection limit of 0.29 ng/mL.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Grafite , Limite de Detecção , Zearalenona , Zearalenona/análise , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação , Grafite/química , Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas/métodos , Desenho de Equipamento , Ferrocianetos/química , Colorimetria/instrumentação , Colorimetria/métodos
2.
Emerg Microbes Infect ; 13(1): 2373314, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38922326

RESUMO

The proportion of human isolates with reduced neuraminidase inhibitors (NAIs) susceptibility in highly pathogenic avian influenza (HPAI) H7N9 virus was high. These drug-resistant strains showed good replication capacity without serious loss of fitness. In the presence of oseltamivir, R229I substitution were found in HA1 region of the HPAI H7N9 virus before NA R292K appeared. HPAI H7N9 or H7N9/PR8 recombinant viruses were developed to study whether HA R229I could increase the fitness of the H7N9 virus bearing NA 292K. Replication efficiency was assessed in MDCK or A549 cells. Neuraminidase enzyme activity and receptor-binding ability were analyzed. Pathogenicity in C57 mice was evaluated. Antigenicity analysis was conducted through a two-way HI test, in which the antiserum was obtained from immunized ferrets. Transcriptomic analysis of MDCK infected with HPAI H7N9 24hpi was done. It turned out that HA R229I substitution from oseltamivir induction in HA1 region increased (1) replication ability in MDCK(P < 0.05) and A549(P < 0.05), (2) neuraminidase enzyme activity, (3) binding ability to both α2,3 and α2,6 receptor, (4) pathogenicity to mice(more weight loss; shorter mean survival day; viral titer in respiratory tract, P < 0.05; Pathological changes in pneumonia), (5) transcriptome response of MDCK, of the H7N9 virus bearing NA 292K. Besides, HA R229I substitution changed the antigenicity of H7N9/PR8 virus (>4-fold difference of HI titre). It indicated that through the fine-tuning of HA-NA balance, R229I increased the fitness and changed the antigenicity of H7N9 virus bearing NA 292K. Public health attention to this mechanism needs to be drawn.


Assuntos
Antivirais , Subtipo H7N9 do Vírus da Influenza A , Neuraminidase , Infecções por Orthomyxoviridae , Oseltamivir , Replicação Viral , Animais , Oseltamivir/farmacologia , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/efeitos dos fármacos , Subtipo H7N9 do Vírus da Influenza A/patogenicidade , Subtipo H7N9 do Vírus da Influenza A/imunologia , Subtipo H7N9 do Vírus da Influenza A/fisiologia , Neuraminidase/genética , Neuraminidase/metabolismo , Cães , Replicação Viral/efeitos dos fármacos , Antivirais/farmacologia , Humanos , Camundongos , Infecções por Orthomyxoviridae/virologia , Células Madin Darby de Rim Canino , Células A549 , Camundongos Endogâmicos C57BL , Farmacorresistência Viral/genética , Substituição de Aminoácidos , Influenza Humana/virologia , Furões , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Feminino , Proteínas Virais/genética , Proteínas Virais/metabolismo
3.
Front Nutr ; 11: 1349162, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38660064

RESUMO

Pectin was extracted from Actinidia arguta Sieb. et Zucc (A.arguta) using the ultrasound-assisted acid method and the single acid method. The physicochemical properties, structure, and antioxidant properties of two different pectins were investigated. The results showed that the extraction yield of the ultrasound-assisted acid method is higher than that of the single acid method. The molecular structure of A. arguta pectin extracted by the ultrasound-assisted acid method belongs to a mixed structure of RG-I and HG-type domains. Through structural feature analysis, the ultrasound-assisted extraction pectin (UAP) has a more branched structure than the single acid-extracted pectin (SAP). The SAP has a higher degree of esterification than the UAP. The physical property results show that the viscosity, solubility, and water-holding capacity of the UAP are better than those of the SAP. The antioxidant test results show that the hydroxyl radical scavenging and reducing powers of the UAP are superior to those of the SAP. This study shows the composition, physicochemical properties, and antioxidant activity of A. arguta pectin extracted by the ultrasonic-assisted extraction method to provide a theoretical basis for its application as an antioxidant and other food additives in the food industry.

4.
Small ; 20(25): e2309582, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38225695

RESUMO

Electrocatalysis is considered to be an effective method to solve the sluggish kinetics of lithium-sulfur batteries. However, a single catalyst cannot simultaneously catalyze multi-step sulfur reductions. And once the catalyst surface is covered by the initially deposited solid products, the subsequent catalytic activity will significantly deteriorate. Here, microporous ZIF-67 and its derivative nano-metallic Co0 are used as dual-catalyst aiming to address these drawbacks. The dual catalytic center effectively cooperates the adsorption and electron transfer for multi-steps of sulfur reductions, transforming the potential-limited step (Li2S4→Li2S2/Li2S) into a thermodynamic spontaneous reaction. ZIF-67 first adsorbs soluble Li2S4 to form a coordination structure of ZIF-Li2S4. Then nano-metallic Co0 attracts uncoordinated S atoms in ZIF-Li2S4 and facilitates the breaking of S-S bonds to form transient reductive ZIF-Li2S2 and Co-S2 via. spontaneous electron transfer. These intermediates facilitate continuous conversion to Li2S with reduced formation energy, which is beneficial to the regeneration of the catalyst. As a result, the cathode with ZIF@CNTs/Co@CNFs synergetic catalyst achieves initial areal capacity of 4.7 mAh cm-2 and maintains 3.5 mAh cm-2 at low electrolyte/sulfur ratio (E/S) of 5 µL mg-1. This study provides valuable guidance for improving the electrochemical performance of lithium-sulfur batteries through catalyst synergistic strategies for multi-step reactions.

5.
Clin Exp Optom ; : 1-7, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37989320

RESUMO

CLINICAL RELEVANCE: Raising children's myopia prevention awareness and behaviour tends to exhibits a protective effect against myopia among schoolchildren. BACKGROUND: To investigate the effect of an original myopia song in raising school children's awareness of healthier eye use behaviour and on myopia prevention. METHODS: In this prospective randomised control study, two groups of students from one primary schools in Jiangxi, China, were enrolled and monitored from grade 3 to grade 6 (2016-2019). The primary outcome was the change in axial length (AL) after the intervention. Secondary outcomes included changes in spherical equivalent refraction (SER), near work and outdoor time, corrected near and distant visual acuity, visual discomfort score (VDS) and accommodative lag. RESULTS: Four hundred students (193 females, 48.25%) aged 9.3 (range 8-10) years with emmetropia to moderate myopia were enrolled. Children in the myopia song group had a significantly shorter AL and less myopic refractive change than those in the control group (p = 0.04 and 0.02, respectively). Compared with the control group, children in the myopia song group spent less time on near work and more time outdoors (p = 0.04 and 0.04, respectively). At the final follow-up, the proportion of children with myopia was significantly lower in the myopia song group (30.5%) than in the control group (41%) (p = 0.03). No significant differences were found for the secondary outcomes, including corrected near and distant visual acuity, VDS and accommodative lag. CONCLUSIONS: An original myopia song performed twice daily in primary schools appeared to have a modest effect on myopia control among school-aged children by changing their lifestyles in the long term.

6.
Biosens Bioelectron ; 240: 115651, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37666010

RESUMO

The global spread of environmental biological pollutants, such as antibiotic-resistant bacteria and their antibiotic resistance genes (ARGs), has emerged as a critical public health concern. It is imperative to address this pressing issue due to its potential implications for public health. Herein, a DNA paperclip probe with double-quenching function of target cyclic cleavage was proposed, and an electrochemiluminescence (ECL) biosensing platform was constructed using Ti3C2 MXene in-situ reduction growth of Au NPs (TCM-Au) as a coreactant accelerator, and applied to the sensitive detection of ARGs. Thanks to the excellent catalytic performance, large surface area and Au-S affinity of TCM-Au, the ECL performance of CdS QDs have been significantly improved. By cleverly utilizing the negative charge of the paperclip nucleic acid probe and its modification group, double-quenching of the ECL signal was achieved. This innovative approach, combined with target cyclic amplification, facilitated specific and sensitive detection of the mecA gene. This biosensing platform manifested highly selective and sensitive determination of mecA genes in the range of 10 fM to 100 nM and a low detection limit of 2.7 fM. The credible detectability and anti-interference were demonstrated in Yangtze river and Aeration tank outlet, indicating its promising application toward pollution monitoring of ARGs.


Assuntos
Técnicas Biossensoriais , Poluentes Ambientais , Titânio , Antibacterianos , Resistência Microbiana a Medicamentos
7.
J Biophotonics ; 16(11): e202300133, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37369631

RESUMO

OBJECTIVE: To evaluate the effect of hydroxychloroquine on conjunctival and retinal microvascular density in rheumatoid arthritis (RA) patients. METHODS: Ten healthy controls, 10 RA patients who had not been treated with hydroxychloroquine, and 10 RA patients who had been treated with chloroquine for more than 5 years were recruited. Optical coherence tomography (OCTA) was used to examine the conjunctival and superficial and deep retinal microvascular density and compared the differences in microvascular density between the three groups. RESULTS: The vascular density in RA group in superficial microvascular was significantly lower than that in control group (p < 0.001). Compared with RA group, the chloroquine group showed statistically significantly lower microvascular (p < 0.001) and deep microvascular (p = 0.018). Superficial microvascular was positively correlated with conjunctival vessel density in RA patients (r = 0.868, p = 0.0048). CONCLUSIONS: The use of chloroquine could further reduce the vascular density in the absence of statistical difference in the course of the disease.


Assuntos
Artrite Reumatoide , Hidroxicloroquina , Humanos , Hidroxicloroquina/uso terapêutico , Hidroxicloroquina/farmacologia , Vasos Retinianos/diagnóstico por imagem , Cloroquina/uso terapêutico , Cloroquina/farmacologia , Angiofluoresceinografia/métodos , Artrite Reumatoide/diagnóstico por imagem , Artrite Reumatoide/tratamento farmacológico , Tomografia de Coerência Óptica/métodos
9.
Brain Sci ; 12(8)2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-36009141

RESUMO

PURPOSE: To investigate the altered functional connectivity (FC) of the cerebral hemispheres in patients with morbid obesity (MO) with meibomian gland dysfunction (MGD) by voxel-mirrored homotopic connectivity (VMHC). METHODS: Patients and matched healthy controls (HCs) were recruited, and all subjects underwent functional resonance magnetic imaging (fMRI), and VMHC results were processed statistically to assess the differences in FC in different brain regions between the two groups. We further used ROC curves to evaluate the diagnostic value of these differences. We also used Pearson's correlation analysis to explore the relationship between changes in VMHC values in specific brain regions, visual acuity, and Mini-Mental State Examination (MMSE) score. CONCLUSIONS: Patients with morbid obesity and MGD had abnormal FC in the cerebral hemispheres in several specific brain areas, which were mainly concentrated in pathways related to vision and perception and may correlate to some extent with the clinical presentations of the patients.

10.
Front Hum Neurosci ; 16: 900409, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35693538

RESUMO

Purpose: To investigate spontaneous brain activity in patients with dry eye (DE) and healthy control (HC) using the fractional amplitude of low frequency fluctuation (fALFF) technique with the aim of elucidating the relationship between the clinical symptoms of DE and changes in brain function. Material and Methods: A total of 28 patients with DE and 28 matched healthy volunteers (10 males and 18 females in each group) were enrolled. Resting-state functional magnetic resonance imaging scans were performed in both groups. Then all subjects were required to complete a comprehensive Hospital Anxiety and Depression Scale (HADS). Receiver operating characteristic (ROC) curve analysis was used to evaluate the differences in fALFF values between the two groups and their diagnostic value. Linear correlations between HADS and fALFF values in different brain regions of DE patients were analyzed using the Pearson correlation coefficient. Results: Patients with DE had significantly higher fALFF values in the left calcarine sulcus (CS) than the HC group, while fALFF values in the bilateral middle frontal gyrus (MFG) and right MFG/right inferior frontal gyrus (IFG) were significantly lower in DE patients than in HC group. fALFF values had a high diagnostic value for differentiating patients with DE from the HC group (P < 0.001). Right MFG and right MFG/IFG were significantly correlated with HADS values. Conclusion: Our study found that DE mainly involved functional disorders in the brain areas of the left CS, bilateral MFG and right MFG/right IFG, which helped us to find possible clinical features of DE disease and reflected the potential pathological mechanism of DE.

11.
Front Aging Neurosci ; 14: 877281, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35493938

RESUMO

Objective: To analyze the potential changes in brain neural networks in resting state functional magnetic resonance imaging (rs-fMRI) scans by regional homogeneity (ReHo) in patients with mild cognitive impairment (MCI). Methods: We recruited and selected 24 volunteers, including 12 patients (6 men and 6 women) with MCI and 12 healthy controls matched by age, sex, and lifestyle. All subjects were examined with rs-fMRI to evaluate changes in neural network connectivity, and the data were analyzed by ReHo method. Correlation analysis was used to investigate the relationship between ReHo values and clinical features in different brain regions of MCI patients. The severity of MCI was determined by the Mini-Mental State Examination (MMSE) scale. Results: The signals of the right cerebellum areas 4 and 5, left superior temporal, right superior temporal, left fusiform, and left orbital middle frontal gyri in the patient group were significantly higher than those in the normal group (P < 0.01 by t-test of paired samples). The signal intensity of the right inferior temporal and left inferior temporal gyri was significantly lower than that of the normal group (P < 0.01). The ReHO value for the left inferior temporal gyrus correlated negatively with disease duration, and the value for the right inferior temporal gyrus correlated positively with MMSE scores. Conclusion: Mild cognitive impairment in patients with pre- Alzheimer's disease may be related to the excitation and inhibition of neural networks in these regions. This may have a certain guiding significance for clinical diagnosis.

12.
Emerg Infect Dis ; 28(7): 1332-1344, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35476714

RESUMO

The recent rise in the frequency of influenza A(H5N6) infections in China has raised serious concerns about whether the risk for human infection has increased. We surveyed epidemiologic, clinical, and genetic data of human infections with A(H5N6) viruses. Severe disease occurred in 93.8% of cases, and the fatality rate was 55.4%. Median patient age was 51 years. Most H5N6 hemagglutinin (HA) genes in human isolates in 2021 originated from subclade 2.3.4.4b; we estimated the time to most recent common ancestor as June 16, 2020. A total of 13 genotypes with HA genes from multiple subclades in clade 2.3.4.4 were identified in human isolates. Of note, 4 new genotypes detected in 2021 were the major causes of increased H5N6 virus infections. Mammalian-adapted mutations were found in HA and internal genes. Although we found no evidence of human-to-human transmission, continuous evolution of H5N6 viruses may increase the risk for human infections.


Assuntos
Vírus da Influenza A , Influenza Aviária , Influenza Humana , Animais , China/epidemiologia , Humanos , Mamíferos , Pessoa de Meia-Idade , Filogenia , Vírus Reordenados/genética
13.
Front Microbiol ; 13: 845088, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35387078

RESUMO

Seasonal influenza A (H3N2) virus has been a concern since its first introduction in humans in 1968. Accumulating antigenic changes in viral hemagglutinin (HA), particularly recent cocirculations of multiple HA genetic clades, allow H3N2 virus evade into humans annually. From 2010, the binding of neuraminidase (NA) to sialic acid made the traditional assay for HA inhibition antibodies (Abs) unsuitable for antigenicity characterization. Here, we investigated the serum anti-NA response in a cohort with a seroconversion of microneutralizing (MN) Abs targeting the circulating strain, A/Singapore/INFIMH-16-0019/2016 (H3N2, 3C.2a1)-like, a virus during 2018/2019 flu seasons. We discovered that MN Ab titers show no difference between children and adults. Nevertheless, higher titers of Abs with NA activity inhibition (NI) activity of 129 and seroconversion rate of 68.42% are presented in children aged 7-17 years (n = 19) and 73.47 and 41.17% in adults aged 21-59 years (n = 17), respectively. The MN Abs generated in children display direct correlations with HA- and NA-binding Abs or NI Abs. The NI activity exhibited cross-reactivity to N2 of H3N2 viruses of 2007 and 2013, commonly with 329-N-glycosylation and E344 in N2, a characteristic of earlier 3C.2a H3N2 virus in 2014. The percentage of such viruses pronouncedly decreased and was even replaced by those dominant H3N2 viruses with E344K and 329 non-glycosylation, which have a significantly low activity to the tested antisera. Our findings suggest that NI assay is a testable assay applied in H3N2 infection in children, and the antigenic drift of current N2 should be considered for vaccine selection.

14.
J Integr Neurosci ; 21(1): 4, 2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35164440

RESUMO

Functional connectivity of the primary visual cortex was explored with resting functional magnetic resonance imaging among adults with strabismus and amblyopia and healthy controls. We used the two-sample test and receiver operating characteristic curves to investigate the differences in mean functional connectivity values between the groups with strabismus and amblyopia and healthy controls. Compared with healthy controls, functional connectivity values in the left Brodmann areas 17, including bilateral lingual/angular gyri, were reduced in groups with strabismus and amblyopia. Moreover, functional connectivity values in the right Brodmann area 17, including left cuneus, right inferior occipital gyrus, and left inferior parietal lobule, were reduced in adults with strabismus and amblyopia. Our findings indicate that functional connectivity abnormalities exist between the primary visual cortex and other regions. This may be the basis of the pathological mechanism of visual dysfunction and stereovision disorders in adults with strabismus and amblyopia.


Assuntos
Ambliopia/fisiopatologia , Conectoma , Córtex Visual Primário/fisiopatologia , Estrabismo/fisiopatologia , Adulto , Ambliopia/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Visual Primário/diagnóstico por imagem , Estrabismo/diagnóstico por imagem , Adulto Jovem
15.
Influenza Other Respir Viruses ; 16(3): 577-584, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35037399

RESUMO

BACKGROUND: The first and only case of human infection with the avian influenza A (H7N4) virus in China emerged in 2018. The H7N4 virus was distinct from previous H7N9 viruses and raised public concerns. Therefore, developing a suitable H7N4 candidate vaccine virus (CVV) remains crucial for potential pandemic preparedness. METHODS: We constructed a reassortant virus with a (6 + 2) genome composition, then introduced the polymerase basic protein 1 (PB1) from a wild-type virus to develop a (5 + 3) reassortant virus through reverse genetics. We performed whole-genome sequencing to confirm the genome stability, assessed the growth ability in MDCK cells, and analyzed virus antigenicity using hemagglutination inhibition assays. Subsequently, the effect of homologous PB1 on polymerase activity, viral protein yield, and pathogenicity was assessed. RESULTS: The (5 + 3) virus harbouring the homologous PB1 gene exhibited significantly improved growth characteristics, higher viral protein yield, and polymerase activity than the (6 + 2) virus. After successive passage in embryonated eggs, glutamic acid (E) substituted glycine(G) at position 218 (H3 numbering) in the hemagglutinin (HA) gene of both (5 + 3) and (6 + 2) viruses. The substitution improved the growth of the (6 + 2) virus but exhibited no significant effect or alteration on the antigenicity of the (5 + 3) virus. Moreover, the (5 + 3) virus exhibited low pathogenicity in chickens and ferrets. CONCLUSION: Homologous PB1 of the H7N4 virus improves the growth ability while sustaining low pathogenicity. Collectively, the gene composition of the (5 + 3) reassortant virus is a suitable H7N4 CVV for potential pandemic preparedness.


Assuntos
Subtipo H7N9 do Vírus da Influenza A , Vacinas contra Influenza , Influenza Aviária , Vacinas , Animais , Galinhas , Furões , Humanos , Subtipo H7N9 do Vírus da Influenza A/genética , Vacinas contra Influenza/genética , Influenza Aviária/prevenção & controle , Vírus Reordenados/genética , Replicação Viral
16.
Sci Rep ; 11(1): 16293, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381119

RESUMO

That the high frequency and good replication capacity of strains with reduced susceptibility to neuraminidase inhibitors (NAIs) in highly pathogenic avian influenza H7N9 (HPAI H7N9) virus made it a significance to further study its drug resistance. HPAI H7N9 viruses bearing NA I222L or E119V substitution and two mutations of I222L-E119V as well as their NAIs-sensitive counterpart were generated by reverse genetics for NA inhibition test and replication capability evaluation in vitro. The attenuated H7N9/PR8 recombinant viruses were developed to study the pathogenicity and drug resistance brought by the above substitutions to mice. The IC50 fold change of oseltamivir to HPAI H7N9 with NA222L-119V is 306.34 times than that of its susceptible strain, and 3.5 times than the E119V mutant virus. HPAI H7N9 bearing NA222L-119V had good replication ability with peak value of more than 6log10 TCID50/ml in MDCK cells. H7N9/PR8 virus bearing NA222L-119V substitutions leaded to diffuse pneumonia, significant weight loss and fatality in mice. NA E119V made H7N9/PR8 virus resistant to oseltamivir, and I222L-E119V had synergistic resistance to oseltamivir in mice. Due to the good fitness of drug resistant strains of HPAI H7N9 virus, it is necessary to strengthen drug resistance surveillance and new drug research.


Assuntos
Substituição de Aminoácidos/genética , Farmacorresistência Viral/genética , Subtipo H7N9 do Vírus da Influenza A/efeitos dos fármacos , Subtipo H7N9 do Vírus da Influenza A/genética , Neuraminidase/genética , Oseltamivir/farmacologia , Substituição de Aminoácidos/efeitos dos fármacos , Animais , Antivirais/farmacologia , Aves/virologia , Linhagem Celular , Cães , Inibidores Enzimáticos/farmacologia , Feminino , Células HEK293 , Humanos , Influenza Aviária/tratamento farmacológico , Influenza Aviária/virologia , Influenza Humana/tratamento farmacológico , Influenza Humana/virologia , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos C57BL , Mutação/genética , Infecções por Orthomyxoviridae/tratamento farmacológico , Infecções por Orthomyxoviridae/virologia , Proteínas Virais/genética , Replicação Viral/efeitos dos fármacos , Replicação Viral/genética
17.
Virus Genes ; 57(2): 164-171, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33606171

RESUMO

Influenza vaccines represent the most effective preventive strategy to control influenza virus infections; however, adaptive mutations frequently occur in the hemagglutinin (HA) glycoprotein during the preparation of candidate vaccine virus and production of vaccine in embryonated eggs. In our previous study, we constructed candidate vaccine virus (HA-R) to match the highly pathogenic avian influenza H7N9 viruses A/Guangdong/17SF003/2016 as part of a pandemic preparedness program. However, mixed amino acids (R, G, and I) were presented at position 220 (H3 numbering) in HA during passage in embryonated eggs. The residue at position 220 is located close to the receptor-binding site and the biological characteristics of this site remain to be elucidated. Therefore, in this study, using reverse genetics, we constructed two viruses carrying the single substitution in position 220 of HA (HA-G and HA-I) and evaluated the biological effects of substitution (R with G/I) on receptor binding, neuraminidase (NA) activity, growth characteristics, genetic stability, and antigenicity. The results revealed both mutant viruses exhibited lower HA binding affinities to two receptor types (sialic acid in alpha2,3- and alpha2,6-linkage to galactose, P < 0.001) and significant better growth characteristics compared to HA-R in two cells. Moreover, under similar NA enzymatic activity, the two mutant viruses eluted more easily from agglutinated erythrocytes than HA-R. Collectively, these results implied the balance of HA and NA in mutant viruses was a stronger determinant of viral growth than the individual amino acid in the HA position 220 in HA-R without strong binding between HA and sialylated receptors. Importantly, both the substitutions conferred altered antigenicity to the mutant viruses. In conclusion, amino acid substitutions at position 220 can substantially influence viral biological properties.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Subtipo H7N9 do Vírus da Influenza A/genética , Vacinas contra Influenza/genética , Substituição de Aminoácidos , Animais , Cães , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Subtipo H7N9 do Vírus da Influenza A/imunologia , Vacinas contra Influenza/química , Vacinas contra Influenza/imunologia , Células Madin Darby de Rim Canino , Mutagênese , Ácido N-Acetilneuramínico/metabolismo , Neuraminidase/metabolismo , Vírus Reordenados/genética , Vírus Reordenados/imunologia , Genética Reversa
18.
Nanomedicine ; 32: 102339, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33227538

RESUMO

MicroRNA (miRNA) has emerged as a promising genetic marker for cancer diagnosis and therapy because its expression level is closely related to the progression of malignant diseases. Herein, a label-free and selective fluorescence platform was proposed for miRNA based on light-up "G-quadruplex nanostring" via duplex-specific nuclease (DSN) mediated tandem rolling circle amplification (RCA). First, a long DNA generated from upstream RCA was designed with the antisense sequences for miR-21 and downstream RCA primer. Upon recognizing miR-21, the resulting DNA-RNA permitted DSN digestion and triggered downstream two-way RCA, and generation of abundant "G-quadruplex nanostring" binding with ZnPPIX for label-free fluorescent responses. In our strategy, the strong preference of DSN for perfectly matched DNA/RNA ensures its excellent selectivity. The developed method generated wide linear response with LOD of 1.019 fM. Additionally, the miR-21 levels in cell extracts have been evaluated, revealing the utility of this tool for biomedical research and clinical diagnosis.


Assuntos
Endonucleases/metabolismo , Quadruplex G , MicroRNAs/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Estudos de Viabilidade , Células HeLa , Humanos , MicroRNAs/metabolismo , Espectrometria de Fluorescência
19.
Anal Methods ; 12(24): 3092-3097, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32930168

RESUMO

Developing a sensitive, low-cost and general sensing platform for the analysis of a DNA biomarker and its mutation is important for early cancer screening. In our work, the tumor suppressor gene-p53 DNA was chosen as the model DNA biomarker due to its vital role in preventing oncogene cancer-inhibiting activity through mediating cellular proliferation and apoptosis. Compared with tumor biopsy, the quantification of p53 DNA and its mutation in biofluids (such as urine) is more convenient due to its simple operation and non-invasiveness. Herein, a label-free amplified fluorescence assay has been developed for p53 DNA in urine samples through the KFP polymerase-driven double strand displacement reactions and a magnetic nanoprobe. First, the ssDNA probe (RP) was designed with antisense sequences for p53 DNA and the Nb.BbvCI endonuclease recognition site. In the presence of p53 DNA, the formed dsDNA between RP and p53 DNA served as an engaging primer to initiate the first strand displacement reaction (SDA) under the action of KFP DNA polymerase and Nb.BbvCI, generating abundant short ssDNA (primer). Subsequently, the resulting primers will initiate the downstream SDA through the primer-hairpin DNA (HPa) binding, opening up, and extension of HPb and HPc under the action of KFP DNA polymerase. In the process of this final DNA polymerization reaction, the primer hybridized on HPa is released and goes on to initiate another round, forming plenty of duplex Y-shaped DNA. With the integration of SYBR Green I (SG I) into these duplex DNA, the amplified label-free fluorescence detection platform for p53 DNA can be achieved. Moreover, a biotin modified nanoprobe (bio-CP) was used to capture the superfluous HP. By performing the separation function, the binding of superfluous HP and SG could be avoided and a low background can be acquired. Benefiting from the abundant SG intercalation sites of Y-shaped DNA and low background signals, this method showed excellent sensitivity with a detection limit of 0.012 nM, and the p53 DNA in urine samples was evaluated, offering a powerful tool for biomedical research and clinical diagnosis.


Assuntos
DNA , Técnicas de Amplificação de Ácido Nucleico , Biotina , DNA/genética , DNA de Cadeia Simples/genética , Polimerização
20.
Analyst ; 145(22): 7448, 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-32966362

RESUMO

Correction for 'A facile deoxyuridine/biotin-modified molecular beacon for simultaneous detection of proteins and nucleic acids via a label-free and background-eliminated fluorescence assay' by Fei Yin, et al., Analyst, 2019, 144, 5504-5510, DOI: 10.1039/C9AN01016E.

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