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1.
Microb Pathog ; : 104061, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-32061916

RESUMO

To compare different nanoparticle-based nasal vaccines against foot-and-mouth disease (FMD), chitosan (CS)-coated poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) (CS/PLGA-NPs) and amino-functionalized mesoporous silica nanoparticles (Am/MSNs) loaded with FMDV recombinant plasmid (pP12A3C/IFN-CS/PLGA-NPs and pP12A3C/IFN-Am/MS-NPs) were used to induce mucosal and systemic immune responses in guinea pigs via intranasal delivery. Simultaneously, CpG oligodeoxy nucleotides (ODNs) as a vaccine adjuvant were encapsulated in chitosan-coated poly (lactic-co-glycolic acid) nanoparticles (CpG-CS/PLGA-NPs). The pP12A3C/IFN-CS/PLGA-NPs and CpG-CS/PLGA-NPs generated displayed good morphology, high stability, mean diameters of 500 and 400 nm and encapsulation efficiencies of 83.8% and 88.4%, respectively. Data from the in vitro release assay showed that plasmid and CpG were sustainably released from nanoparticles (up to 66.73% and 64%, respectively, of the total amount loaded). Guinea pigs immunized with pP12A3C/IFN-CS/PLGA-NPs + CpG-CS/PLGA-NPs showed markedly higher mucosal, cellular and humoral immune responses than those administered pP12A3C/IFN-CS/PLGA-NPs or naked plasmid vaccine alone. FMDV-specific secretory immunoglobulin A (sIgA) antibodies in nasal washes were initially detected at 3 days post-vaccination with CS/PLGA-NPs loaded with plasmid. Guinea pigs immunized with pP12A3C/IFN-CS/PLGA-NPs also displayed higher cellular and humoral immune responses than pP12A3C-CS/PLGA-NPs and naked plasmid vaccine alone. FMDV-specific immunoglobulin G (IgG) antibodies in serum were initially detected at 5 days post-vaccination (intramuscularly) with the naked plasmid. Finally, challenge experiments 42 days post-vaccine revealed 100% protection in guinea pigs immunized with pP12A3C/IFN-CS/PLGA-NPs + CpG-CS/PLGA-NPs and pP12A3C/IFN-CS/PLGA-NPs. However, plasmid DNA was burst released from pP12A3C/IFN-Am/MS-NPs. Our attempts to use pP12A3C/IFN-Am/MS-NPs to immunize guinea pigs failed to induce immune responses. In conclusion, CpG and IFN-α adjuvant based FMD vaccines elicit protection in guinea pigs. Moreover, CS-coated PLGA NPs present an efficient and safe mucosal immune delivery system for FMDV DNA vaccine. Data from the current study provide a foundation for understanding and further evaluating protective immune responses in pigs.

2.
Biomed Res Int ; 2019: 8530273, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31687402

RESUMO

In recent years, many studies have shown that recombinant adenovirus live vector-based vaccines are a promising novel vaccine candidate against virus infection. Therefore, in this study, a new type of recombinant adenovirus expressing the spike (S) protein of porcine epidemic diarrhea virus (PEDV), rAd-PEDV-S, was generated, and its characteristics were determined. Then, its efficacy as a vaccine candidate was evaluated in 4-week-old pigs. The results showed that the S protein could be well expressed at a high level in rAd-PEDV-S-infected cells and that the viral titers could reach 1011 PFU/mL. Further animal experimental results showed that rAd-PEDV-S elicited a significant PEDV-specific humoral immune response after vaccination (P < 0.05). In addition, rAd-PEDV-S provided partial protection for pigs against the highly virulent PEDV challenge. The results presented in this study indicate that the adenovirus vector can be used as a vaccine delivery vector for the development of a PEDV vaccine and is a promising novel vaccine candidate for future prevention and control of porcine epidemic diarrhea (PED), but its efficacy still needs to be improved in the future.

3.
Eur J Pharm Biopharm ; 144: 217-229, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31563632

RESUMO

Poor encapsulation and high initial burst were two major obstacles for the water-soluble peptide drug loaded microspheres preparation using the industrial emulsification method. In the present study, we hypothesized that the hydrophobic ion-pairing (HIP) complex strategy with a further healing of the pores within the microspheres may improve drug encapsulation and initial burst release. DSS was chosen as the most suitable one among the three test ion-pairing agents (SDS, DSS and STC) due to its high binding efficiency with drug and reversible dissociation capacity in presence of counter ions. The formation of HIP complex between octreotide acetate and DSS successfully reversed the highly water-soluble nature of the drug. A specific S/O/W method was adopted to encapsulate such drug containing HIP complex. The encapsulation efficiency of the drug was greatly improved compared with the conventional W1/O/W2 method (from 44% to 90%). Under the optimal healing conditions (the healing time 6 h, temperature 40 °C and 4% DEP content), the pores within the microspheres were effectively healed. Initial burst amount of octreotide acetate in S/O/W microspheres decreased to 3.56%. The pore healing effect was further confirmed by the scanning electron microscopy and fluorescence microscopy results. In the process of testing the drug release performance of such new strategy in vitro and in vivo, a more satisfactory single phase release profile with sustained and steady drug release was observed. These results suggested that the modified HIP strategy could be a promising platform for water-soluble peptide encapsulation with high encapsulation efficiency, low initial burst and stable drug release mechanism.


Assuntos
Liberação Controlada de Fármacos/efeitos dos fármacos , Íons/química , Peptídeos/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Animais , Composição de Medicamentos/métodos , Interações Hidrofóbicas e Hidrofílicas , Masculino , Microscopia Eletrônica de Varredura/métodos , Microesferas , Tamanho da Partícula , Ratos , Ratos Sprague-Dawley , Solventes/química , Temperatura Ambiente , Água/química
4.
Colloids Surf B Biointerfaces ; 183: 110453, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31465940

RESUMO

Photodynamic therapy (PDT) is a prospective approach to cure tumor diseases. However, tumor micro-environment is notably characterized with severe hypoxia and high expression of glutathione (GSH), which seriously limit its clinical application. Here, based on the characteristics of perfluorocarbon (PFC) to dissolve substantial oxygen (O2) and the sensitivity of reductive GSH to S-NO group, we designed GSH depletion and dual-model O2 supply strategies to promote PDT enhancement. The PFC nanoliposomes (FI@Lip) and biocompatible NO donor S-nitrosated human serum albumin (HSA-SNO) were combined to synergistically combat the obstacle of tumor micro-environment, reducing GSH concentration and increasing singlet oxygen (1O2) generation. In vitro, after irradiation with NIR laser, the PFC in FI@Lip dissolved more O2 to increase 1O2 generation. In addition, with co-delivery of HSA-SNO, it can effectively promote GSH depletion to recover 1O2 level and release NO concurrently to inhibit mitochondrial respiration. This combination strategy of FI@Lip and HSA-SNO obviously relieved intracellular hypoxia and decreased GSH to increase more toxic 1O2 generation for PDT enhancement. The present work will play as an enlightening role in PDT design and clinical application in the near future.

5.
Pharm Res ; 36(8): 119, 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31165279

RESUMO

PURPOSE: The purpose of this study was to characterize and detail the mechanism of a smart Ca2+ release depot (Ca3(PO4)2) about its ability for sustainable inhibition on peptide acylation within PLGA microspheres. METHODS: The octreotide acetate release and acylation kinetics were analyzed by RP-HPLC. Changes of Ca2+ concentration and adsorption behavior were determined by a Calcium Colorimetric Assay Kit. The inner pH changes were delineated by a classic pH sensitive probe, Lysosensor yellow/ blue® dextran. Morphological changes of microspheres, adsorption between polymer and additive, transformation of Ca3(PO4)2 were characterized using SEM, FTIR and SSNMR separately. RESULTS: Before and after microspheres formulation, the property and effectiveness of Ca3(PO4)2 were investigated. Compared with a commonly used calcium salt (CaCl2), high encapsulation efficiency (96.56%) of Ca3(PO4)2 guarantees lasting effectiveness. In an increasingly acidic environment that simulated polymer degradation, the poorly water-soluble Ca3(PO4)2 could absorb protons and transform into the more and more soluble CaHPO4 and Ca(H2PO4)2 to produce sufficient Ca2+ according to severity of acylation. The corresponding Ca2+ produce capacity fully met the optimum inhibition requirement since the real-time adsorption sites (water-soluble carboxylic acids) inside the degrading microspheres were rare. A sustained retention of three switchable calcium salts and slow release of Ca2+ were observed during the microsphere incubation. FTIR results confirmed the long-term inhibition effect induced by Ca3(PO4)2 on the adsorption between drug and polymer. CONCLUSIONS: With the presence of the smart Ca2+ depot (Ca3(PO4)2) in the microspheres, a sustainable and long-term inhibition of peptide acylation was achieved.


Assuntos
Cálcio/química , Microesferas , Peptídeos/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Acilação , Adsorção , Fosfatos de Cálcio/química , Cátions Bivalentes , Portadores de Fármacos , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Cinética , Octreotida/química , Prótons , Solubilidade , Eletricidade Estática , Água/química
6.
Appl Opt ; 58(10): 2551-2555, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31045050

RESUMO

With increased power of spectral beam combination, surface heat distortion of multilayer dielectric gratings (MDGs) could occur. In this study, the damage morphology of MDGs was initially analyzed under a continuous-wave laser irradiation. Subsequently, the surface distortion and temperature rise of different MDGs were tested experimentally. The experimental results showed that the initial damage of MDGs was caused by the thermal stress. Further, the thermal stress of the multilayer dielectric films on the MDG surface was analyzed theoretically. The calculated results were in good agreement with the experimental results. The conclusions indicated that with the increase of the MDG surface temperature, the stress in the HfO2 layers initially reached the stress damage threshold of the dielectric films and, therefore, the damage occurred.

7.
Acta Biomater ; 92: 241-253, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31078766

RESUMO

Carbon monoxide (CO)-based gas therapy has emerged as an attractive therapeutic strategy for cancer therapy. However, the main challenges are the in situ-triggered and efficient delivery of CO in tumors, which limit its further clinical application. Herein, we developed an erythrocyte membrane-biomimetic gas nanofactory (MGP@RBC) to amplify the in situ generation of CO for combined energy starvation of cancer cells and gas therapy. This nanofactory was constructed by encapsulating glucose oxidase (GOx) and Mn2(CO)10 (CO-donor) into the biocompatible polymer poly(lactic-co-glycolic acid), obtaining MGP nanoparticles, which are further covered by red blood cell (RBC) membrane. Because of the presence of proteins on RBC membranes, the nanoparticles could effectively avoid immune clearance in macrophages (Raw264.7) and significantly prolong their blood circulation time, thereby achieving higher accumulation at the tumor site. After that, the GOx in GMP@RBC could effectively catalyze the conversion of endogenous glucose to hydrogen peroxide (H2O2) in the presence of oxygen. The concomitant generation of H2O2 could efficiently trigger CO release to cause dysfunction of mitochondria and activate caspase, thereby resulting in apoptosis of the cancer cells. In addition, the depletion of intratumoral glucose could starve tumor cells by shutting down the energy supply. Altogether, the in vitro and in vivo studies of our synthesized biomimetic gas nanofactory exhibited an augmentative synergistic efficacy of CO gas therapy and energy starvation to inhibit tumor growth. It provides an attractive strategy to amplify CO generation for enhanced cancer therapy in an accurate and more efficient manner. STATEMENT OF SIGNIFICANCE: Carbon monoxide (CO) based gas therapy has emerged as an attractive therapeutic strategy for cancer therapy. In this study, we developed an erythrocyte membrane biomimetic gas nanofactory to amplify the in-situ generation of CO for combined cancer starvation and gas therapy. It is constructed by coating glucose oxidase (GOx) and CO donor-loaded nanoparticles with erythrocyte membrane. Due to the erythrocyte membrane, it can effectively prolong blood circulation time and achieve higher tumor accumulation. After accumulated in tumor, endogenous glucose can be effectively catalyzed to hydrogen peroxide, in-situ amplified CO release to induce the apoptosis of cancer cells. In addition, depleting glucose can also starve tumor cells by shutting down the energy supply. Overall, our biomimetic gas nanofactory exhibits an augmentative synergistic efficacy of CO gas therapy and starvation to increased tumor inhibition. It provide a novel strategy to deliver CO in an accurate and more efficient manner, promising for combined cancer therapy in future clinical application.

8.
Eur J Pharm Sci ; 134: 69-80, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31002985

RESUMO

Polymer degradation within the controlled-release depots comprising of lactide and glycolide (PLGA) forms an acidic microenvironment, in which severe acylation of the peptide by the polymer degradation products takes place. The aim of this study was to make out the role of the inner µpH on peptide acylation within the microspheres and how could it influence the reaction. The effects of pH on the acylation reaction within microspheres were composed of two aspects. Firstly, the inherent effect of pH on the acylation reaction itself was figured out: with the pH environment going up from acid to neutral, a model peptide (octreotide acetate) acylation became more and more serious. Then, the multivariate effect of pH on the dynamic microsphere delivery system especially the state of the acylation substrates (drug and oligomer) was investigated. When the inner pH was neutralized by Ca(OH)2 to varying degrees, polymer degradation rate, drug release rate, polymer degradation mechanism and oligomer accumulation state within the microspheres all changed. These changes highly affected the mass transfer of the acylation substrates to the external release medium. Neutralization of the µpH prolonged the retention time of drug and oligomer within the microspheres. Water absorption and single microsphere swelling experiments all showed a higher retention amount of acylation substrates during the critical period for peptide acylation. Generally, when the inner µpH was neutralized, except that the neutral environment itself promoted acylation reaction, the effects of pH on the dynamic system were also highly responsible for the serious acylation within the microspheres.


Assuntos
Concentração de Íons de Hidrogênio , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Polímeros/química , Acilação , Aminoacilação , Sistemas de Liberação de Medicamentos/métodos , Desenvolvimento de Medicamentos/métodos , Liberação Controlada de Fármacos , Cinética , Microesferas
9.
Nanoscale ; 11(12): 5474-5488, 2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30855625

RESUMO

Clinical chemotherapy for cancer is limited by the physiological barrier of tumors, resulting in low drug delivery to tumors, poor efficacy of drugs and inability to block tumor metastasis. Here we developed an intelligent switchable nitric oxide (NO)-releasing nanoparticle, IPH-NO, which loads a photosensitizer (IR780) and the chemotherapy drug paclitaxel (PTX) into NO donor-S-nitrosated human serum albumin (HSA-NO). NO exhibits two effects based on its concentration: enhancement of chemotherapy by increasing the enhanced permeability and retention (EPR) effect at low concentrations and direct killing of cancer cells at high concentrations. IPH-NO can slowly release NO in the presence of glutathione to boost tumor vascular permeability and improve drug accumulation. Near-infrared light irradiation was utilized to induce a quick release of NO that can directly kill cancer cells at high concentrations. This combination of phototherapy and NO gas therapy activated by NIR together with chemotherapy showed significant effects in tumor inhibition. Furthermore, IPH-NO blocked tumor metastasis by inhibiting epithelial mesenchymal transition. PH-NO provides a novel strategy to control NO release at tumor site for drug accumulation and combination therapies, consequently potentiating the anticancer efficacy and inhibiting tumor metastasis.


Assuntos
Nanomedicina , Nanopartículas/química , Óxido Nítrico/metabolismo , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Glutationa/química , Meia-Vida , Humanos , Hipotermia Induzida , Raios Infravermelhos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos ICR , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Paclitaxel/química , Paclitaxel/farmacocinética , Paclitaxel/farmacologia , Paclitaxel/uso terapêutico , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacocinética , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Albumina Sérica Humana/química , Oxigênio Singlete/análise
10.
AAPS PharmSciTech ; 20(4): 155, 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30924008

RESUMO

In this paper, a novel formulation of dual-release dry suspension of mosapride citrate (DRDS-MC) was designed which can be quickly released in the stomach while having sustained-release effect. Co-grinding mixture of mosapride citrate (MC) together with L-HPC as hydrophilic excipient was prepared in order to improve the solubility of MC. The co-grinding mixture was characterized by solubility studies, DSC, X-RD, SEM, FTIR, and size distribution before the preparation of the DRDS-MC. Then, the co-grinding mixture was used to prepare DRDS-MC via wet granulation method. The evaluation of DRDS-MC was focused on physicochemical properties, intestinal absorption, and pharmacokinetics. The results of DSC, X-RD, SEM, FTIR, and size distribution indicated that MC resides in co-grinding mixture with no crystalline changes, hydrogen bonds made L-HPC greatly improving the solubility of MC. Then, the dissolution of DRDS-MC reached 70% in pH 1.2 within 2 h, and the 12-h dissolution of MC in pH 6.8 was nearly 80%. The sedimentation volume after 3 h was 0.94 and redispersibility was good. The linear regression equation between in vitro release of DRDS-MC and intestinal absorption fraction in rats was: Y = 29.215 + 47.535*X (r = 0.952). At last, pharmacokinetic studies in beagle dogs demonstrated that DRDS-MC has prolonged effect compared with commercial formulation Gasmotin as a reference. All results indicated that the DRDS-MC could be quickly released in the stomach while having sustained-release effect.


Assuntos
Benzamidas/síntese química , Benzamidas/farmacocinética , Absorção Gastrointestinal/efeitos dos fármacos , Fármacos Gastrointestinais/síntese química , Fármacos Gastrointestinais/farmacocinética , Morfolinas/síntese química , Morfolinas/farmacocinética , Animais , Estudos Cross-Over , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/farmacocinética , Cães , Avaliação Pré-Clínica de Medicamentos/métodos , Liberação Controlada de Fármacos/efeitos dos fármacos , Liberação Controlada de Fármacos/fisiologia , Excipientes/síntese química , Excipientes/farmacocinética , Absorção Gastrointestinal/fisiologia , Masculino , Distribuição Aleatória , Ratos , Solubilidade , Suspensões
11.
Appl Microbiol Biotechnol ; 103(8): 3367-3379, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30888465

RESUMO

Many recent studies have shown that flagellin fused to heterologous antigens can induce significantly enhanced humoral and cellular immune responses through its adjuvant activity. Therefore, in this study, two key B cell epitopes and a truncated VP1 (ΔVP1) protein from foot-and-mouth disease virus (FMDV) were expressed as flagellin fusion proteins in different patterns. Specifically, ΔVP1 and two duplicates of two key B cell epitopes (2×B1B2) were fused separately to the C-terminus of flagellin with a universal exogenous T cell epitope to construct FT (Flagellin-Truncated VP1) and FME (Flagellin-Multiple Epitopes). In addition, the D3 domain of flagellin was replaced by ΔVP1 in FME, yielding FTME (Flagellin-Truncated VP1-Multiple Epitopes). The immunogenicity and protective efficacy of the three fusion proteins as novel FMDV vaccine candidates were evaluated. The results showed that FT, FME, and FTME elicited significant FMDV-specific IgG responses at 10 µg/dose compared with the mock group (P < 0.05), with FTME producing the highest response. No significant differences in the antibody response to FTME were observed between different immunization routes or among adjuvants (ISA-206, poly(I·C), MPLA, and CpG-ODN) in mice. In addition, at 30 µg/dose, all three fusion proteins significantly induced neutralizing antibody production and upregulated the levels of some cytokines, including TNF-α, IFN-γ, and IL-12, in guinea pigs. Importantly, all three fusion proteins provided effective protective immunity against FMDV challenge in guinea pigs, though different protection rates were found. The results presented in this study indicate that the FTME fusion protein is a promising novel vaccine candidate for the future prevention and control of foot-and-mouth disease.


Assuntos
Flagelina/imunologia , Vírus da Febre Aftosa/imunologia , Febre Aftosa/prevenção & controle , Vacinação/métodos , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Antígenos Virais/genética , Antígenos Virais/imunologia , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/imunologia , Citocinas/sangue , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Feminino , Flagelina/genética , Vírus da Febre Aftosa/genética , Cobaias , Masculino , Camundongos Endogâmicos BALB C , Proteínas Recombinantes de Fusão/administração & dosagem , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Vacinas Virais/administração & dosagem , Vacinas Virais/genética
12.
Appl Environ Microbiol ; 85(11)2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30902862

RESUMO

The genus Shewanella comprises a group of marine-dwelling species with worldwide distribution. Several species are regarded as causative agents of food spoilage and opportunistic pathogens of human diseases. In this study, a standard multilocus sequence analysis (MLSA) based on six protein-coding genes (gyrA, gyrB, infB, recN, rpoA, and topA) was established as a rapid and accurate identification tool in 59 Shewanella type strains. This method yielded sufficient resolving power in regard to enough informative sites, adequate sequence divergences, and distinct interspecies branches. The stability of phylogenetic topology was supported by high bootstrap values and concordance with different methods. The reliability of the MLSA scheme was further validated by identical phylogenies and high correlations of genomes. The MLSA approach provided a robust system to exhibit evolutionary relationships in the Shewanella genus. The split network tree proposed twelve distinct monophyletic clades with identical G+C contents and high genetic similarities. A total of 86 tested strains were investigated to explore the population biology of the Shewanella genus in China. The most prevalent Shewanella species was Shewanella algae, followed by Shewanella xiamenensis, Shewanella chilikensis, Shewanella indica, Shewanella seohaensis, and Shewanella carassii The strains frequently isolated from clinical and food samples highlighted the importance of increasing the surveillance of Shewanella species. Based on the combined genetic, genomic, and phenotypic analyses, Shewanella upenei should be considered a synonym of S. algae, and Shewanella pacifica should be reclassified as a synonym of Shewanella japonica IMPORTANCE The MLSA scheme based on six housekeeping genes (HKGs) (gyrA, gyrB, infB, recN, rpoA, and topA) is well established as a reliable tool for taxonomic, evolutionary, and population diversity analyses of the genus Shewanella in this study. The standard MLSA method allows researchers to make rapid, economical, and precise identification of Shewanella strains. The robust phylogenetic network of MLSA provides profound insight into the evolutionary structure of the genus Shewanella The population genetics of Shewanella species determined by the MLSA approach plays a pivotal role in clinical diagnosis and routine monitoring. Further studies on remaining species and genomic analysis will enhance a more comprehensive understanding of the microbial systematics, phylogenetic relationships, and ecological status of the genus Shewanella.

13.
Vet Microbiol ; 230: 278-282, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30827401

RESUMO

Although highly virulent GII-genotype PEDV strains have become pandemic in the swine population worldwide, little is known about the differences in immunogenicity and cross-protective efficacy between the GIIa and GIIb subgenotypes. Hence, in the present study, we vaccinated suckling piglets with GIIa (CH/HBXT/2018) and GIIb (CH/HNPJ/2017) PEDV strain-based inactivated vaccine candidates and compared their immunogenicity and cross-protective efficacy. The results showed that both vaccine candidates induced high levels of PEDV-specific IgG antibodies and IFN-γ and reduced the levels of neutralizing antibodies at 21 dpv in suckling piglets. The GIIa-based inactivated vaccine protected all piglets (8/8) against virulent homologous and heterologous virus challenge, while the GIIb strain-based inactivated vaccine protected only 2/4 and 1/4 piglets against virulent homologous and heterologous virus challenge, respectively. Furthermore, antibodies against the GIIa and GIIb strains cross-reacted and cross-neutralized both strains in vitro. Taken together, the data presented in this study indicate that GIIa strain-based inactivated vaccine candidates are more promising than GIIb-based candidates for the development of an effective vaccine against the current highly virulent pandemic PEDV strains.


Assuntos
Anticorpos Antivirais/sangue , Infecções por Coronavirus/veterinária , Proteção Cruzada/imunologia , Imunogenicidade da Vacina , Doenças dos Suínos/prevenção & controle , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Técnicas de Cultura de Células , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Genótipo , Imunoglobulina G/sangue , Interferon gama/imunologia , Vírus da Diarreia Epidêmica Suína/genética , Vírus da Diarreia Epidêmica Suína/patogenicidade , Suínos , Doenças dos Suínos/imunologia , Vacinas de Produtos Inativados/imunologia , Vacinas Virais/administração & dosagem , Eliminação de Partículas Virais
14.
Arch Virol ; 164(5): 1287-1295, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30859476

RESUMO

Since 2010, continual outbreaks of highly virulent variants of porcine epidemic diarrhea virus (PEDV) belonging to genotype GII have led to serious economic losses for the Chinese swine industry. To better understand the biological characteristics and pathogenicity of the current prevalent Chinese PEDV field strains, in this study, a highly virulent Chinese genotype GIIa PEDV strain, CH/HBXT/2018, was isolated and serially propagated using Vero cells. Sequencing and phylogenetic analysis showed that strain CH/HBXT/2018 contained novel insertion and deletion mutations in the S gene region relative to the classical strain and belonged to the genotype GIIa, similar to other recently isolated PEDV strains from China and the United States. Pig infection studies indicated that the CH/HBXT/2018 strain was highly virulent in suckling piglets, and the median pig diarrhea dose (PDD50) was 8.63 log10PDD50/3 mL at 7 days postinfection (DPI). The results of the present study are important for future PEDV challenge studies and the development of new PEDV vaccines based on prevalent field strains for the prevention and control of PED in China.


Assuntos
Infecções por Coronavirus/veterinária , Vírus da Diarreia Epidêmica Suína/genética , Vírus da Diarreia Epidêmica Suína/patogenicidade , Glicoproteína da Espícula de Coronavírus/genética , Animais , Linhagem Celular , China , Infecções por Coronavirus/virologia , Surtos de Doenças , Genótipo , Mutagênese Insercional/genética , Filogenia , Vírus da Diarreia Epidêmica Suína/classificação , Vírus da Diarreia Epidêmica Suína/isolamento & purificação , Deleção de Sequência/genética , Suínos , Doenças dos Suínos/virologia , Células Vero , Vacinas Virais/imunologia , Virulência/genética
15.
J Pharm Sci ; 108(7): 2367-2376, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30802455

RESUMO

The purpose of the present study was to make a detailed comparison of 2 similar additives about their opposite effects on the initial burst of octreotide acetate from poly(lactic-co-glycolic acid) microspheres. We focused on identifying the key factor that influenced the initial burst of microspheres induced by small hydrophilic additives. The apparent reason resulting in such differences was different pore closing rates on the surface of these 2 batches. However, the potential mechanism was still unknown. To compare with the single-additive system, these 2 additives were coencapsulated together into the same formulation. Of surprise, the inhibition effect of glucose on burst release somehow disappeared and even turned out to be opposite. This phenomenon greatly reminds us that there must be some interactions between glucose and polymer, which are likely to be disturbed by coencapsulated CaCl2. However, small amount of additive can hardly make any detected difference. Therefore, additive-loaded microspheres without drug were prepared to further investigate the potential factors. Under this condition, differences were found. The key factor for glucose-induced accelerated pore closure and reduction in initial burst was the formation of hydrogen bonds between the glucose molecule and the polymer matrix.

16.
Int J Syst Evol Microbiol ; 69(3): 852-858, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30663957

RESUMO

Eight swarming motile bacteria were isolated from food and clinical samples in China. Cells were Gram-stain-negative, facultatively anaerobic and rod-shaped (0.5-0.8×1.0-3.0 µm) with hairlike pili and flagella. The 16S rRNA and partial rpoB housekeeping gene sequence analyses indicated that the strains belong to the genus Proteusin the family Enterobacteriaceae. Of the eight strains studied, seven and a single isolate formed two separate clades in the phylogeny of Proteusspecies, indicating two separate species. Both the in silico DNA-DNA hybridization and the average nucleotide identity values between these two groups and to the type strains of the genus Proteuswere below the recommended threshold for signifying their candidature as two separate species. The DNA G+C contents of strains TJ1636T and FJ2001126-3T were 37.8 and 38.1 mol%, respectively. The major cellular fatty acids of the two novel type strains were C16:0, cyclo C17:0, summed feature 3 and summed feature 8. The results supported that the strains belong to different taxonomic positions in the genus Proteus. The isolates were named Proteus faecis sp. nov., with type strain TJ1636T (=DSM 106180T=GDMCC 1.1245T), and Proteuscibi sp. nov., with type strain FJ2001126-3T (=DSM 106178T =GDMCC 1.1244T).


Assuntos
Fezes/microbiologia , Microbiologia de Alimentos , Filogenia , Proteus/classificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Humanos , Hibridização de Ácido Nucleico , Proteus/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
17.
Virus Res ; 259: 18-27, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30342075

RESUMO

Since October 2010, severe porcine epidemic diarrhea (PED) outbreaks caused by highly virulent PED virus (PEDV) strains have occurred continuously in the Chinese pig population and caused considerable economic losses. Although PEDV vaccines based on classical PEDV strains have been widely used in China in recent years, the morbidity and mortality in piglets remain high. Therefore, virulent genotype GII PEDV strains that are prevalent in the field should be isolated and used to develop next-generation vaccines. In the present study, a Chinese virulent genotype GIIb PEDV strain, CH/HNPJ/2017, was serially propagated in Vero cells for up to 90 passages. The S genes contained typical insertions and deletions that were also found in other recently isolated highly virulent PEDV strains from China and other countries and had two neighboring unique insertion mutations, which resulted in four amino acid changes in the S1 region of passages P10 and P60. Pig infection studies revealed that the CH/HNPJ/2017 strain was highly virulent in piglets, and the median pig diarrhea dose (PDD50) was 7.68 log10PDD50/3 mL. Furthermore, the cell-adapted CH/HNPJ/2017 strain elicited potent serum IgG and neutralizing antibody responses in immunized pigs when it was used as an inactivated vaccine candidate. In addition, the pigs that received the experimental inactivated vaccines were partially protected (3/5) against subsequent viral challenge. In brief, these data indicate that the CH/HNPJ/2017 strain is a promising candidate for developing a safe and effective PEDV vaccine in the future.


Assuntos
Infecções por Coronavirus/veterinária , Genótipo , Vírus da Diarreia Epidêmica Suína/genética , Doenças dos Suínos/virologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linhagem Celular , Diarreia/veterinária , Interações Hospedeiro-Patógeno/imunologia , Testes de Neutralização , Filogenia , Vírus da Diarreia Epidêmica Suína/classificação , Vírus da Diarreia Epidêmica Suína/imunologia , Vírus da Diarreia Epidêmica Suína/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Suínos , Doenças dos Suínos/imunologia , Doenças dos Suínos/patologia , Doenças dos Suínos/prevenção & controle , Vacinas de Produtos Inativados/imunologia , Células Vero , Vacinas Virais/imunologia , Virulência
18.
Rev Sci Instrum ; 89(7): 073102, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30068144

RESUMO

The measurement of the spectral diffraction efficiencies of a diffraction grating is essential for improving the manufacturing technique and for assessing the grating's function in practical applications. The drawback of the currently popular measurement technique is its slow speed due to the hundreds of repetitions of two kinds of time-consuming mechanical movements during the measuring process (i.e., the rotation of the mechanical arm to capture the light beam and the mechanical variation of the output wavelength of the grating monochromator). This limitation greatly restricts the usage of this technique in dynamic measurement. In this manuscript, we present a motionless and fast measurement technique for obtaining the spectral diffraction efficiencies of a plane grating, effectively eliminating the aforementioned two kinds of mechanical movements. Herein, the proposed solution for removing the first kind of mechanical movement is tested, and the experimental result shows that the proposed method can be successfully used to measure the plane transmission grating's spectral diffraction efficiencies in the wavelength range of 550-750 nm. The method for eliminating the second kind of mechanical movement is not verified in this manuscript; however, we think that it is very straightforward and commercially available. We estimate that the spectral measurement can be achieved on a millisecond time scale by combining the two solutions. Our motionless and fast measuring technique will find broad applications in dynamic measurement environments and mass industrial testing.

19.
Opt Express ; 26(17): 21675-21684, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-30130870

RESUMO

Spectral beam combination is a promising method for high-radiance lasers with a good beam quality. With the increase of the combination power, the temperature of the multilayer dielectric grating (MDG) unavoidably increases, leading to surface heat distortion of the MDG. In this study, the temperature field equation of the MDG is derived, and the key factors influencing the MDG temperature are investigated. Furthermore, experiments are performed to confirm the calculation results. The results reveal that the increase of the thickness of the substrate can improve the power tolerance of the MDG but delays the stable output of beam laser; use of a substrate material with a large thermal conductivity can greatly reduce the temperature of the MDG.

20.
Appl Opt ; 57(18): D165-D170, 2018 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-30117946

RESUMO

In previous research, the thermal distortion and far-field beam quality of a spectral beam combining grating were analyzed by theory and experiment under the irradiation of a high-power continuous-wave laser. It was concluded that the thermal expansion of the substrate was the main cause of the grating distortion and decrease in the beam quality. However, there was no further study to determine a method to decrease the heat deposition on the grating surface and far-field beam quality factor, M2. In this paper, we theoretically simulate the influence of the substrate thickness on the temperature field distribution and far-field beam quality of a multilayer dielectric grating. An experimental setup is proposed to verify the theoretical calculations. The experimental results are in good agreement with the calculations. The conclusions indicate that the temperature rise of the grating and M2 are effectively reduced by increasing the thickness of the substrate.

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