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The direct elucidation of the reaction pathways in heterogeneous catalysis has been challenging due to the short-lived nature of reaction intermediates. Here, we directly measured on ultrafast time scales the initial hydrogenation steps of adsorbed CO on a Ru catalyst surface, which is known as the bottleneck reaction in syngas and CO2 reforming processes. We initiated the hydrogenation of CO with an ultrafast laser temperature jump and probed transient changes in the electronic structure using real-time X-ray spectroscopy. In combination with theoretical simulations, we verified the formation of CHO during CO hydrogenation.
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AIM: To gain insight into the presence of islet cell autoimmunity in an ethnic Asian compared with a white European population. METHODS: For this cross-sectional study we recruited people with adult-onset diabetes (age of diagnosis 20-60 years), at tertiary referral centres in Germany (n=1020) and Singapore (n=1088). Glutamic acid decarboxylase and islet antigen 2 antibodies were measured according to Islet Autoantibody Standardization Program protocols. RESULTS: The prevalence of glutamic acid decarboxylase antibody positivity was 13.9% (95% CI 12.1-16.0; P<0.001) in the white European cohort compared with 6.8% (95% CI 5.5-8.4; P<0.001) in the Asian cohort. Glutamic acid decarboxylase antibody positivity was 11.4% (95% CI 7.7-16.6) in Indian, 6.0% (95% CI 3.6-9.9) in Malay and 5.8% (95% CI 4.3-7.7; P<0.001) in Chinese participants. In the white European participants, the prevalence of islet antigen 2 antibody positivity was 7.8% (95% CI 6.4-9.4) compared with 14.8% (95% CI 12.8-17.0; P<0.001) in the Asian cohort as a whole, and among the three ethnicities in the Asian cohort it was 12.4% (95% CI 8.6-17.7) in Indian, 16.8% (95% CI 12.6-22.2) in Malay and 15.7% (95% CI 13.2-18.6) in Chinese participants. Double antibody positivity was seen in 5.7% (95% CI 4.5-7.1) of white European participants compared with 1.6% (95% CI 1.0-2.5; P<0.01) of Asian participants. In the white European cohort, those who were glutamic acid decarboxylase autoantibody-positive had a lower BMI than those who were autoantibody-negative, but this trend was absent in the Asian cohort. CONCLUSIONS: A marked prevalence of islet cell autoimmunity was observed in people with adult-onset diabetes. While glutamic acid decarboxylase antibodies were more frequent in the European cohort, islet antigen 2 antibody positivity was highest in the three ethnic groups in Singapore, suggesting ethnic-specific differences in antibody profiles.
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Autoanticorpos/análise , Doenças Autoimunes/imunologia , Autoimunidade , Diabetes Mellitus Tipo 2/imunologia , Glutamato Descarboxilase/antagonistas & inibidores , Proteínas Tirosina Fosfatases Classe 8 Semelhantes a Receptores/antagonistas & inibidores , Adulto , Povo Asiático , Doenças Autoimunes/sangue , Doenças Autoimunes/epidemiologia , Doenças Autoimunes/etnologia , Biomarcadores/sangue , Estudos de Coortes , Estudos Transversais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/etnologia , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Encaminhamento e Consulta , Singapura/epidemiologia , Centros de Atenção Terciária , População Branca , Adulto JovemRESUMO
Using x-ray photoelectron spectroscopy we observe the breaking of the strong interatomic bond in molecular CO at low temperature on a stepped Cu surface. Since the electronic structure of Cu does not allow for the splitting of CO at such low temperatures it suggests that there may be a less obvious pathway for the process. Through x-ray photoelectron spectroscopy we can clearly identify products associated with the dissociation of CO and the subsequent formation of stable graphitic carbon on the surface. However, the dissociation of CO can be inhibited when the stepped Cu surface is kept clean from surface carbon. These observations imply that the reaction is driven by the presence of small amounts of weakly bound carbon at the surface. Density-functional theory calculations confirm that carbon atoms on a stepped Cu surface indeed are the preferred adsorption sites for CO, which increases the stabilization of CO on the surface and weakens the C-O bond. This results in the breaking of the C-O bond at the step edge via the Boudouard reaction (2CO(ads)âC(ads)+CO(2)) with a barrier of 0.71 eV.
RESUMO
We show that coadsorbed oxygen atoms have a dramatic influence on the CO desorption dynamics from Ru(0001). In contrast to the precursor-mediated desorption mechanism on Ru(0001), the presence of surface oxygen modifies the electronic structure of Ru atoms such that CO desorption occurs predominantly via the direct pathway. This phenomenon is directly observed in an ultrafast pump-probe experiment using a soft x-ray free-electron laser to monitor the dynamic evolution of the valence electronic structure of the surface species. This is supported with the potential of mean force along the CO desorption path obtained from density-functional theory calculations. Charge density distribution and frozen-orbital analysis suggest that the oxygen-induced reduction of the Pauli repulsion, and consequent increase of the dative interaction between the CO 5σ and the charged Ru atom, is the electronic origin of the distinct desorption dynamics. Ab initio molecular dynamics simulations of CO desorption from Ru(0001) and oxygen-coadsorbed Ru(0001) provide further insights into the surface bond-breaking process.
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We describe a new in operando approach for the investigation of heterogeneous processes at solid/liquid interfaces with elemental and chemical specificity which combines the preparation of thin liquid films using the meniscus method with standing wave ambient pressure X-ray photoelectron spectroscopy [Nemsák et al., Nat. Commun., 5, 5441 (2014)]. This technique provides information about the chemical composition across liquid/solid interfaces with sub-nanometer depth resolution and under realistic conditions of solution composition and concentration, pH, as well as electrical bias. In this article, we discuss the basics of the technique and present the first results of measurements on KOH/Ni interfaces.
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Femtosecond x-ray laser pulses are used to probe the carbon monoxide (CO) oxidation reaction on ruthenium (Ru) initiated by an optical laser pulse. On a time scale of a few hundred femtoseconds, the optical laser pulse excites motions of CO and oxygen (O) on the surface, allowing the reactants to collide, and, with a transient close to a picosecond (ps), new electronic states appear in the O K-edge x-ray absorption spectrum. Density functional theory calculations indicate that these result from changes in the adsorption site and bond formation between CO and O with a distribution of OC-O bond lengths close to the transition state (TS). After 1 ps, 10% of the CO populate the TS region, which is consistent with predictions based on a quantum oscillator model.
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BACKGROUND AND PURPOSE: Neuroimaging has demonstrated that improved speech outcomes in Parkinson's Disease (PD) subsequent to behavioural treatment approaches are associated with increased activity in the motor and pre-motor cortex. High-frequency repetitive transcranial magnetic stimulation (rTMS) is capable of modulating cortical activity and has been reported to have significant benefit to general motor function in PD. It is possible that high-frequency rTMS may also have beneficial outcomes on speech production in PD. METHODS: High-frequency (5 Hz) rTMS was applied to 10 active stimulation and 10 sham placebo patients for 10 min/day (3000 pulses), for 10 days and speech outcome measures and lingual kinematic parameters recorded at baseline and 1 week, 2 and 12 months post-stimulation. RESULTS: The findings demonstrated positive treatment-related changes observed in the active rTMS group when compared to the sham placebo control group at 2 and 12 months post-stimulation in speech intelligibility, communication efficiency ratio, maximum velocity of tongue movements and distance of tongue movements. CONCLUSION: The results support the use of high-frequency rTMS as a therapeutic tool for the treatment of articulatory dysfunction in PD.
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Córtex Motor/fisiopatologia , Doença de Parkinson/terapia , Distúrbios da Fala/terapia , Inteligibilidade da Fala/fisiologia , Estimulação Magnética Transcraniana/métodos , Idoso , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/complicações , Doença de Parkinson/fisiopatologia , Distúrbios da Fala/etiologia , Distúrbios da Fala/fisiopatologia , Resultado do TratamentoRESUMO
This is the first pathological description of 'scale drop syndrome' (SDS) in Asian seabass, Lates calcarifer Bloch. Cumulative mortality was estimated at 40-50%. The vasculitis in all major organs including the skin and associated tissue necrosis was distinctive. The dermis overlying scale beds was often necrotic and associated with scale loss. Necrosis of splenic ellipsoids, renal glomeruli and choroid rete glands of eye were further hallmarks of a disease with systemic vascular involvement. The brain was not spared vascular damage, and the resulting multifocal encephalomalacia probably accounts for the spiral swimming behaviour in some affected fish. Other lesions included accentuated hepatic lobulation and gastric gland necrosis. Nuclear chromatin margination and karyolysis in hepatocytes, renal tubular epithelium and gastric and intestinal epithelium suggest specific targeting of cells. Basophilic cytoplasmic inclusions were present in spleen, kidney, liver, heart and choroid rete, but they were not prominent. Using transmission electron microscopy, two morphological forms of virions were observed: single- and double-enveloped hexagonal virions. Based on size and morphology, these virions resemble iridovirus or herpesvirus. The cause of SDS is unknown, but the pathological changes, especially the vasculitis, suggest an infectious aetiology, possibly viral.
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Bass , Doenças dos Peixes/patologia , Animais , Ásia , Doenças dos Peixes/mortalidade , Doenças dos Peixes/virologia , Microscopia Eletrônica de Transmissão , Síndrome , Vírion/ultraestruturaRESUMO
We report on a new nanopatterned structure represented by a single atomic layer of hexagonal boron nitride (h-BN) forming long periodic waves on the Fe(110) surface. The growth process and the structure of this system are characterized by X-ray absorption (XAS), core-level photoemission spectroscopy (CL PES), low-energy electron microscopy (LEEM), microbeam low-energy electron diffraction (µLEED), and scanning tunneling microscopy (STM). The h-BN monolayer on Fe(110) is periodically corrugated in a wavy fashion with an astonishing degree of long-range order, periodicity of 2.6 nm, and the corrugation amplitude of â¼0.8 Å. The wavy pattern results from a strong chemical bonding between h-BN and Fe in combination with a lattice mismatch in either [111] or [111] direction of the Fe(110) surface. Two primary orientations of h-BN on Fe(110) can be observed corresponding to the possible directions of lattice match between h-BN and Fe(110), with approximately equal area of the boron nitride domains of each orientation.
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The process of penetration of cobalt atoms through the h-BN nanomesh on Rh(111) is investigated with both spectroscopic and microscopic techniques. It is discovered that oxygen coadsorption can drastically modify the physical properties and behavior of the deposited Co clusters upon postannealing. In the absence of oxygen, Co forms small nanoparticles in the pores (bonding parts) of the h-BN nanomesh, which start to agglomerate at elevated temperatures without any considerable intercalation. However, even a tiny amount of coadsorbed oxygen reduces cobalt agglomeration and greatly promotes its intercalation and trapping under h-BN. The oxygen exposure necessary for a complete intercalation of 1-2 monolayers of Co is very low, and the formation of oxidic species can be easily avoided. The nanomesh structure remains intact upon intercalating submonolayer amounts of Co, while further intercalation gradually distorts and finally destroys the periodic corrugation. Fortunately, this process is not accompanied by damaging the h-BN sheet itself, and the original structure can be restored by removing Co upon annealing at higher temperatures.
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Compostos de Boro/química , Cobalto/química , Nanoestruturas/química , Oxigênio/química , Adsorção , Compostos de Boro/classificação , Temperatura Alta , Porosidade , Ródio/química , TemperaturaRESUMO
In this study, the efficacies of short hairpin RNAs (shRNAs) targeting different regions of West Nile virus (WNV) strain Sarafend genome were investigated. Short hairpin RNAs targeting Capsid, NS2B and NS4B genes were cloned into pSilencer 3.1-H1 neo and designated as pshCapsid, pshNS2B and pshNS4B, respectively. Vero cells that were positively transfected were selected for creating stable cell lines expressing shRNAs constitutively. These cells were subjected to West Nile virus at multiplicity of infection (M.O.I.) of 10. The cells stably transfected with pshCapsid gave the best silencing effect among the three stable cell lines (transfected with pshCapsid, pshNS2B and pshNS4B) at both 12- and 24 h p.i. When compared to the non-transfected WNV-infected cells, pshCapsid stably transfected cells showed more than 4 log(10) unit reduction in viral transcripts and greater than 3 log(10) unit reduction in virus production. Cells stably transfected with pshNS2B did not exhibit as strong an inhibition when compared to the pshCapsid stably transfected cells having only 2 log(10) unit reduction in virus titre. The pshNS4B-stably transfected cells did not suppress WNV replication. Hence, from this study, pshCapsid has the potential to be developed into effective antiviral strategy for WNV infection.
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Vetores Genéticos , Interferência de RNA , RNA Interferente Pequeno/farmacologia , RNA Viral/metabolismo , Replicação Viral/efeitos dos fármacos , Vírus do Nilo Ocidental/fisiologia , Animais , Chlorocebus aethiops , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA Viral/genética , Transfecção , Células Vero , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vírion/metabolismo , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/metabolismoRESUMO
Tioman virus (TioPV) and Menangle virus (MenPV) are two antigenically and genetically related paramyxoviruses (genus: Rubulavirus, family: Paramyxoviridae) isolated from Peninsular Malaysia (2001) and Australia (1997), respectively. Both viruses are potential zoonotic agents. In the present study, the infectivity, growth kinetics, morphology and morphogenesis of these two paramyxoviruses in a human neuronal cell (SK-N-SH) line were investigated. Sub-confluent SK-N-SH cells were infected with TioPV and MenPV at similar multiplicity of infection. These cells were examined by conventional and immunoelectron microscopy, and virus titres in the supernatants were assayed. Syncytia were observed for both infections in SK-N-SH cells and were more pronounced during the early stages of TioPV infection. The TioPV titre increased consistently (10(1)) every 12 h after infection. In MenPV-infected cells, cellular material was frequently observed within budding virions, and microfilaments and microtubules were abundant. Viral budding was common, and extracellular MenPVs tended to be more pleomorphic compared to TioPVs, which appeared to be more spherical in appearance. The MenPV cytoplasmic viral inclusion appeared to be comparatively smaller, loose and interspersed with randomly scattered circle-like particles, whereas huge tubule-like cytoplasmic inclusions were observed in TioPV-infected cells. Both viruses also displayed different cellular pathology in the SK-N-SH cells. The intracellular ultrastructural characteristics of these two viruses in infected neuronal cells may allow them to be differentiated by electron microscopy.
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Neurônios/patologia , Neurônios/virologia , Infecções por Rubulavirus/patologia , Infecções por Rubulavirus/virologia , Rubulavirus/crescimento & desenvolvimento , Rubulavirus/patogenicidade , Linhagem Celular , Humanos , Microscopia Eletrônica de Transmissão , Microscopia Imunoeletrônica , Morfogênese , Rubulavirus/fisiologia , Rubulavirus/ultraestrutura , Especificidade da Espécie , Montagem de Vírus , Internalização do Vírus , Replicação ViralRESUMO
Dengue virus (DV) is a flavivirus and its urban transmission is maintained largely by its mosquito vectors and vertebrate host, often human. In this study, investigation was carried out on the involvement of domain III of the envelope (E) glycosylated protein of dengue virus serotypes 1 and 2 (DV-1 and DV-2 DIII) in binding to host cell surfaces, thus mediating virus entry. Domain III protein of flavivirus can also serve as an attractive target in inhibiting virus entry. The respective DV DIII proteins were expressed as soluble recombinant fusion proteins before purification through enzymatic cleavage and affinity purification. The purified recombinant DV-1 and DV-2 DIII proteins both demonstrated the ability to inhibit the entry of DV-1 and DV-2 into HepG2 cells and C6/36 mosquito cells. As such, the DV DIII protein is indeed important for the interaction with cellular receptors in both human and mosquito cells. In addition, this protein induced antibodies that completely neutralized homologous dengue serotypes although not with the same efficiency among the heterologous serotypes. This observation may be of importance when formulating a generic vaccine that is effective against all dengue virus serotypes.
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Vírus da Dengue/fisiologia , Proteínas do Envelope Viral/fisiologia , Internalização do Vírus , Animais , Linhagem Celular , Culicidae/citologia , Culicidae/virologia , Vírus da Dengue/metabolismo , Vírus da Dengue/patogenicidade , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Terciária de Proteína , Proteínas do Envelope Viral/metabolismoRESUMO
RNA interference is one of the effective emerging anti-viral strategies to inhibit virus infection in cells. In this study, a small interfering RNA expressing vector (pSilencer-NS5) targeting the NS5 gene of West Nile virus (WNV) was employed to target and destroy WNV transcripts. Real-time PCR revealed drastic reduction in WNV RNA transcripts in pSilencer-NS5-transfected Vero cells. The virus infectious titre was also significantly reduced by 90% as determined by plaque assays. The resulting decrease in virus replication was shown to be specific since both scrambled and nucleotide(s) mismatch siRNA against WNV NS5 gene did not have any effect on WNV productive yields. Furthermore, Western immunoblot analysis on the expression of viral NS5 and envelope (E) proteins showed significant down-regulation on the expression of viral NS5 and envelope (E) proteins in virus-infected cells that were pre-transfected with pSilencer-NS5. These data clearly supported the notion that the expression of vector-based siRNA against WNV NS5 gene is able to exert its silencing effect on WNV-infected cells without inducing cytotoxicity, hence holding promise in therapeutic treatment of this important emerging infectious disease.
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Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteínas não Estruturais Virais/biossíntese , Replicação Viral , Vírus do Nilo Ocidental/fisiologia , Animais , Chlorocebus aethiops , Citoplasma/química , Expressão Gênica , Vetores Genéticos , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Estabilidade de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , RNA Viral/genética , RNA Viral/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Vero , Proteínas do Envelope Viral/biossíntese , Proteínas não Estruturais Virais/genética , Replicação Viral/genética , Vírus do Nilo Ocidental/genéticaRESUMO
The initial interaction between mosquito-borne flavivirus West Nile and mosquito cells is poorly characterized. This study analyzed the endocytic and the associated signaling pathway that mediate the infectious entry of West Nile virus (WNV) into mosquito cell line (C6/36). Pretreatment of C6/36 cells with pharmacological drugs that blocks clathrin-mediated endocytosis significantly inhibited virus entry. Furthermore, the transfection of functional blocking antibody against clathrin molecules and the overexpression of dominant-negative mutants of Eps15 in C6/36 cells caused a marked reduction in WNV internalization. WNV was shown to activate focal adhesion kinase (FAK) to facilitate the endocytosis of virus but not the mitogen-activated protein kinases (ERK1 and ERK2). Subsequent to the internalization of WNV, the virus particles are translocated along the endosomal pathway as revealed by double-immunofluorescence assays with anti-WNV envelope protein and cellular markers for early and late endosomes. Specific inhibitor for protein kinase C (PKC) was shown to be highly effective in blocking WNV entry by inhibiting endosomal sorting event. The disruption of the microtubule network using nocodazole also drastically affects the entry process of WNV but not the disruption of actin filaments by cytochalasin D. Finally, a low-pH-dependent step is required for WNV infection as revealed by the resistance of C6/36 cells to WNV infection in the presence of lysosomotropic agents.
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Aedes/virologia , Endocitose , Vírus do Nilo Ocidental/fisiologia , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Animais , Antígenos Virais/análise , Cadaverina/análogos & derivados , Cadaverina/farmacologia , Linhagem Celular , Clorpromazina/farmacologia , Clatrina/genética , Clatrina/fisiologia , Citocalasina D/farmacologia , Endossomos/virologia , Inibidores Enzimáticos/farmacologia , Filipina/farmacologia , Proteína-Tirosina Quinases de Adesão Focal/análise , Peptídeos e Proteínas de Sinalização Intracelular/genética , Microscopia Confocal , Microscopia de Fluorescência , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Proteínas Quinases Ativadas por Mitógeno/análise , Nocodazol/farmacologia , Proteína Quinase C/antagonistas & inibidores , Sacarose/farmacologiaRESUMO
The complete genome of West Nile (Sarafend) virus [WN(S)V] was sequenced. Phylogenetic trees utilizing the complete genomic sequence, capsid gene, envelope gene and NS5 gene/3' untranslated region of WN(S)V classified WN(S)V as a lineage II virus. A full-length infectious clone of WN(S)V with a point mutation in the glycosylation site of the envelope protein (pWNS-S154A) was constructed. Both growth kinetics and the mode of maturation were affected by this mutation. The titre of the pWNS-S154A virus was lower than the wild-type virus. This defect was corrected by the expression of wild-type envelope protein in trans. The pWNS-S154A virus matured intracellularly instead of at the plasma membrane as shown for the parental WN(S)V.
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Genoma Viral , Proteínas do Envelope Viral/fisiologia , Vírus do Nilo Ocidental/fisiologia , Sequência de Aminoácidos , Animais , Linhagem Celular , Chlorocebus aethiops , Glicosilação , Dados de Sequência Molecular , Alinhamento de Sequência , Especificidade da Espécie , Células Vero , Proteínas do Envelope Viral/classificação , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Replicação Viral , Vírus do Nilo Ocidental/químicaRESUMO
Hand paraesthesia is a common symptom found in patients either with carpal tunnel syndrome or cervical spondylosis. To differentiate between the two conditions, it is important to identify additional diagnostic symptoms. Ninety-two patients with operated carpal tunnel syndrome and 138 patients with spinal surgery for cervical spondylosis were reviewed. After exclusion of cases co-morbid with both cervical spondylosis and carpal tunnel syndrome or other neurological disorders, 44 patients with carpal tunnel syndrome and 41 patients with cervical spondylosis were compared. There were significant differences in the symptomatology between the two groups. In carpal tunnel syndrome, 84% had nocturnal paraesthesia, 82% hand paraesthesia were aggravated by hand activity, and hand pain occurred in 64%. The incidences were only 10%, 7% and 10%, respectively in cervical spondylosis. Neck pain was present in 76% of cervical spondylosis but only in 14% of carpal tunnel syndrome, and lower limb symptoms were present in 44% of cervical spondylosis and only 9% in carpal tunnel syndrome.
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Síndrome do Túnel Carpal/diagnóstico , Vértebras Cervicais/fisiopatologia , Osteofitose Vertebral/diagnóstico , Síndrome do Túnel Carpal/fisiopatologia , Síndrome do Túnel Carpal/cirurgia , Diagnóstico Diferencial , Feminino , Mãos/fisiopatologia , Humanos , Extremidade Inferior/fisiopatologia , Masculino , Pessoa de Meia-Idade , Espasticidade Muscular/fisiopatologia , Debilidade Muscular/fisiopatologia , Dor/etiologia , Dor/fisiopatologia , Parestesia/etiologia , Parestesia/fisiopatologia , Osteofitose Vertebral/fisiopatologia , Osteofitose Vertebral/cirurgiaRESUMO
West Nile (Sarafend) virus [WN(S)V] has been shown to egress by budding at the plasma membrane of infected cells. However, the region influencing this mode of virus release remains to be deciphered. In this study, we have constructed three chimeric clones in which specific regions of West Nile (Wengler) virus [WN(W)V] were replaced for the corresponding regions of WN(S)V in the full-length infectious clone of WN(S)V to define the region responsible for the cis-mode of WN(S)V maturation. The WN(W)V matures by the trans-mode. All of the resulting chimeric viruses were found to be infective. Transmission electron microscopy analyses performed in Vero cells infected with these chimeric viruses disclosed that the 5' end of the WN(S)V genome plays a major role in influencing the process of maturation at the plasma membrane.
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Mapeamento Cromossômico/métodos , Clonagem Molecular/métodos , Genoma Viral , Replicação Viral/genética , Febre do Nilo Ocidental/genética , Febre do Nilo Ocidental/virologia , Vírus do Nilo Ocidental/crescimento & desenvolvimento , Vírus do Nilo Ocidental/genética , Animais , Chlorocebus aethiops , Células Vero , Febre do Nilo Ocidental/patologia , Vírus do Nilo Ocidental/ultraestruturaRESUMO
This study isolated and characterized the West Nile virus (WNV) putative receptor molecule(s) from Aedes albopictus mosquito (C6/36) cells. The binding of WNV to C6/36 cells was saturated with 5000 particles per cell. The entry of WNV into C6/36 cells was strongly inhibited when pretreated with proteinase K and to a lesser extent with sodium periodate. However, pretreatment of C6/36 cells with phospholipases, glycosidases, heparinases and neurimidase had no effect on virus entry. By using virus overlay protein blot assay, WNV was observed to bind to the 140-kDa, 95-kDa, 70-kDa and 55-kDa plasma membrane-associated molecules isolated from C6/36 cells. Murine antibodies generated against the 95-kDa and 70-kDa membrane proteins effectively blocked WNV, Japanese encephalitis virus (JEV) and Dengue virus (DV) serotype 2 infection in C6/36 cells. In addition, the binding of the recombinant-WNV envelope domain III protein to C6/36 cells can be inhibited by the anti-95-kDa and anti-70-kDa membrane protein antibodies. These data strongly supported the possibility that the 95-kDa and 70-kDa plasma membrane-associated proteins are part of a receptor complex for mosquito-borne flaviviruses (WNV, JEV and DV) on mosquito cells.