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1.
Mem. Inst. Oswaldo Cruz ; 116: e200443, 2021. tab, graf
Article in English | LILACS | ID: biblio-1154874

ABSTRACT

BACKGROUND The coronaviruses (CoVs) called the attention of the world for causing outbreaks of severe acute respiratory syndrome (SARS-CoV), in Asia in 2002-03, and respiratory disease in the Middle East (MERS-CoV), in 2012. In December 2019, yet again a new coronavirus (SARS-CoV-2) first identified in Wuhan, China, was associated with a severe respiratory infection, known today as COVID-19. This new virus quickly spread throughout China and 30 additional countries. As result, the World Health Organization (WHO) elevated the status of the COVID-19 outbreak from emergency of international concern to pandemic on March 11, 2020. The impact of COVID-19 on public health and economy fueled a worldwide race to approve therapeutic and prophylactic agents, but so far, there are no specific antiviral drugs or vaccines available. In current scenario, the development of in vitro systems for viral mass production and for testing antiviral and vaccine candidates proves to be an urgent matter. OBJECTIVE The objective of this paper is study the biology of SARS-CoV-2 in Vero-E6 cells at the ultrastructural level. METHODS In this study, we documented, by transmission electron microscopy and real-time reverse transcription polymerase chain reaction (RT-PCR), the infection of Vero-E6 cells with SARS-CoV-2 samples isolated from Brazilian patients. FINDINGS The infected cells presented cytopathic effects and SARS-CoV-2 particles were observed attached to the cell surface and inside cytoplasmic vesicles. The entry of the virus into cells occurred through the endocytic pathway or by fusion of the viral envelope with the cell membrane. Assembled nucleocapsids were verified inside rough endoplasmic reticulum cisterns (RER). Viral maturation seemed to occur by budding of viral particles from the RER into smooth membrane vesicles. MAIN CONCLUSIONS Therefore, the susceptibility of Vero-E6 cells to SARS-CoV-2 infection and the viral pathway inside the cells were demonstrated by ultrastructural analysis.


Subject(s)
Humans , Animals , Vero Cells/virology , Cytoplasmic Vesicles/virology , Cytopathogenic Effect, Viral , SARS-CoV-2/physiology , Chlorocebus aethiops , Nucleocapsid , Reverse Transcriptase Polymerase Chain Reaction , Microscopy, Electron, Transmission , Endocytosis , Endoplasmic Reticulum/virology , Virus Internalization , Real-Time Polymerase Chain Reaction
2.
Chinese Journal of Biotechnology ; (12): 178-186, 2021.
Article in Chinese | WPRIM | ID: wpr-878552

ABSTRACT

In order to establish an infectious clone for CDV-3, a commercial vaccine strain of canine distemper virus for mink, to provide reference for the studies of pathogenesis and novel vaccine development of CDV. Thirteen pairs of primers were used to amplify the full-length genome of CDV-3 strain. Five long fragments were obtained based on single restriction site analysis of the whole genome of CDV-3 by RT-PCR. Five fragments were successively inserted into the multiple clone sites in the modified eukaryotic vector of pcDNA3.2 by restriction enzymes and splicing. Meanwhile, the hammerhead ribozyme and hepatitis delta virus ribozyme sequences were added to the beginning of F1 fragment and the ending of F5 fragment, respectively. Then, the full-length cDNA recombinant plasmid of CDV-3 was obtained and named as pcDNA3.2-CDV-3. In addition, three helper plasmids, expressing the N protein, P protein and L protein of the CDV-3 strain respectively, were constructed. The 293T cells were transfected with the full-length cDNA recombinant plasmid and three helper plasmids by Lipofectamine™ 2000. At 3 days post transfection, the supernatant was added to the monolayer of Vero cells to observe the typical syncytium of CDV. Indirect immunofluorescence and artificial label identification of recombinant virus rCDV-3 were conducted after the occurrence of lesions. Finally, the growth characteristics of wtCDV-3 and rCDV-3 were compared after passaging of rCDV-3. The identification of the full-length cDNA recombinant plasmid and three helper plasmids by restriction enzyme digestion and sequencing were consistent with expected. The Vero cells infected with the recombinant rCDV-3 showed typical syncytic. The identification of indirect immunofluorescence and labeled marker, and observation under electron microscope proved that the rCDV-3 was indeed rescued from the recombinant plasmid of pcDNA3.2-CDV-3. In comparison of the virus titers of wtCDV-3, rCDV-3 replicated massively and rapidly and reached the maximize virus titer of 10⁷·⁶⁶⁷ TCID₅₀/mL within 36 h post infection (p.i.) in Vero cells, while wtCDV-3 grew gradually to 10⁶·⁶⁶⁷ TCID₅₀/mL at 72 h p.i. in Vero cells. This reverse genetic system of CDV-3 strain has been established successfully, to provide reference for the studies of pathogenesis and novel vaccine development of CDV.


Subject(s)
Animals , Chlorocebus aethiops , Clone Cells , DNA, Complementary , Distemper Virus, Canine/genetics , Plasmids/genetics , Vero Cells
3.
Mem. Inst. Oswaldo Cruz ; 115: e200278, 2020. graf
Article in English | LILACS | ID: biblio-1154866

ABSTRACT

BACKGROUND The impact of arbovirus cocirculation in Brazil is unknown. Dengue virus (DENV) reinfection may result in more intense viraemia or immunopathology, leading to more severe disease. The Zika virus (ZIKV) epidemic in the Americas provided pathogenicity evidence that had not been previously observed in flavivirus infections. In contrast to other flaviviruses, electron microscopy studies have shown that ZIKV may replicate in viroplasm-like structures. Flaviviruses produce an ensemble of structurally different virions, collectively contributing to tissue tropism and virus dissemination. OBJECTIVES AND METHODS In this work, the Aedes albopictus mosquito cell lineage (C6/36 cells) and kidney epithelial cells from African green monkeys (Vero cells) were infected with samples of the main circulating arboviruses in Brazil [DENV-1, DENV-2, DENV-3, DENV-4, ZIKV, Yellow Fever virus (YFV) and Chikungunya virus (CHIKV)], and ultrastructural studies by transmission electron microscopy were performed. FINDINGS We observed that ZIKV, the DENV serotypes, YFV and CHIKV particles are spherical. ZIKV, DENV-1, -2, -3 and -4 presented diameters of 40-50 nm, and CHIKV presented approximate diameters of 50-60 nm. Viroplasm-like structures was observed in ZIKV replication cycle. MAIN CONCLUSIONS The morphogenesis of these arboviruses is similar to what has been presented in previous studies. However, we understand that further studies are needed to investigate the relationship between viroplasm-like structures and ZIKV replication dynamics.


Subject(s)
Animals , Arboviruses , Yellow Fever , Dengue/epidemiology , Epidemics , Chikungunya Fever/epidemiology , Zika Virus , Zika Virus Infection/epidemiology , Vero Cells , Brazil/epidemiology , Chlorocebus aethiops
4.
Mem. Inst. Oswaldo Cruz ; 115: e200342, 2020. tab, graf
Article in English | SES-SP, LILACS, SES-SP | ID: biblio-1135273

ABSTRACT

BACKGROUND Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was confirmed in Brazil in February 2020, the first cases were followed by an increase in the number of cases throughout the country, resulting in an important public health crisis that requires fast and coordinated responses. OBJECTIVES The objective of this work is to describe the isolation and propagation properties of SARS-CoV-2 isolates from the first confirmed cases of coronavirus disease 2019 (COVID-19) in Brazil. METHODS After diagnosis in patients that returned from Italy to the São Paulo city in late February by RT-PCR, SARS-CoV-2 isolates were obtained in cell cultures and characterised by full genome sequencing, electron microscopy and in vitro replication properties. FINDINGS The virus isolate was recovered from nasopharyngeal specimen, propagated in Vero cells (E6, CCL-81 and hSLAM), with clear cytopathic effects, and characterised by full genome sequencing, electron microscopy and in vitro replication properties. Virus stocks - viable (titre 2.11 × 106 TCID50/mL, titre 1.5 × 106 PFUs/mL) and inactivated from isolate SARS.CoV2/SP02.2020.HIAE.Br were prepared and set available to the public health authorities and the scientific community in Brazil and abroad. MAIN CONCLUSION We believe that the protocols for virus growth and studies here described and the distribution initiative may constitute a viable model for other developing countries, not only to help a rapid effective pandemic response, but also to facilitate and support basic scientific research.


Subject(s)
Humans , Animals , Pneumonia, Viral , Coronavirus Infections , Pandemics , Betacoronavirus/isolation & purification , Vero Cells , Brazil , Chlorocebus aethiops , SARS-CoV-2 , COVID-19
5.
Article in English | WPRIM | ID: wpr-810955

ABSTRACT

Novel coronavirus (SARS-CoV-2) is found to cause a large outbreak started from Wuhan since December 2019 in China and SARS-CoV-2 infections have been reported with epidemiological linkage to China in 25 countries until now. We isolated SARS-CoV-2 from the oropharyngeal sample obtained from the patient with the first laboratory-confirmed SARS-CoV-2 infection in Korea. Cytopathic effects of SARS-CoV-2 in the Vero cell cultures were confluent 3 days after the first blind passage of the sample. Coronavirus was confirmed with spherical particle having a fringe reminiscent of crown on transmission electron microscopy. Phylogenetic analyses of whole genome sequences showed that it clustered with other SARS-CoV-2 reported from Wuhan.


Subject(s)
China , Coronavirus , Crowns , Genome , Humans , Korea , Microscopy, Electron , Microscopy, Electron, Transmission , Phylogeny , Vero Cells
6.
Chinese Journal of Biotechnology ; (12): 1113-1125, 2020.
Article in Chinese | WPRIM | ID: wpr-826866

ABSTRACT

ORF3 protein, the single accessory protein encoded by porcine epidemic diarrhea virus (PEDV), is related to viral pathogenicity. In order to determine the cytoplasmic location signal of PEDV ORF3, we constructed a series of recombinant plasmids carrying full-length or truncated segments of PEDV DR13 ORF3 protein. When the acquired plasmids were transfected into Vero cells, expression and distribution of the EGFP-fused full-length ORF3 protein and its truncated forms in the cells were observed by laser confocal microscopy. The results showed that ORF3 protein or their truncated forms containing 40-91 aa segment including two transmembrane domains were localized in the cytoplasm, whereas ORF3 truncated peptides without the 40-91 aa segment were distributed in the whole cell (in both cytoplasm and nucleus). This suggests that the 40-91 aa is the key structural domain determining cytoplasmic location of PEDV ORF3 protein. The discovery provides reference for further clarifying intracellular transport and biological function of PEDV ORF3 protein.


Subject(s)
Amino Acid Sequence , Animals , Chlorocebus aethiops , Coronavirus Infections , Virology , Cytoplasm , Virology , Porcine epidemic diarrhea virus , Genetics , Protein Domains , Swine , Vero Cells , Viral Proteins , Chemistry , Metabolism
8.
Mem. Inst. Oswaldo Cruz ; 114: e190150, 2019. tab, graf
Article in English | LILACS | ID: biblio-1020077

ABSTRACT

BACKGROUND Zika virus (ZIKV) infections reported in recent epidemics have been linked to clinical complications that had never been associated with ZIKV before. Adaptive mutations could have contributed to the successful emergence of ZIKV as a global health threat to a nonimmune population. However, the causal relationships between the ZIKV genetic determinants, the pathogenesis and the rapid spread in Latin America and in the Caribbean remain widely unknown. OBJECTIVES The aim of this study was to characterise three ZIKV isolates obtained from patient samples during the 2015/2016 Brazilian epidemics. METHODS The ZIKV genomes of these strains were completely sequenced and in vitro infection kinetics experiments were carried out in cell lines and human primary cells. FINDINGS Eight nonsynonymous substitutions throughout the viral genome of the three Brazilian isolates were identified. Infection kinetics experiments were carried out with mammalian cell lines A549, Huh7.5, Vero E6 and human monocyte-derived dendritic cells (mdDCs) and insect cells (Aag2, C6/36 and AP61) and suggest that some of these mutations might be associated with distinct viral fitness. The clinical isolates also presented differences in their infectivity rates when compared to the well-established ZIKV strains (MR766 and PE243), especially in their abilities to infect mammalian cells. MAIN CONCLUSIONS Genomic analysis of three recent ZIKV isolates revealed some nonsynonymous substitutions, which could have an impact on the viral fitness in mammalian and insect cells.


Subject(s)
Humans , Animals , Aedes/virology , Zika Virus/genetics , Zika Virus Infection/virology , Mice, Inbred BALB C , Phylogeny , Virus Cultivation , Virus Replication , Vero Cells , Brazil , Chlorocebus aethiops , Viral Load
9.
Rev. Soc. Bras. Med. Trop ; 52: e20180511, 2019. graf
Article in English | LILACS | ID: biblio-1003127

ABSTRACT

Abstract INTRODUCTION: Insect cell cultures play an essential role in understanding arboviral replication. However, the replicative efficiency of some of these viruses such as dengue (DENV), yellow fever (YFV), and chikungunya (CHIKV) in a new cellular substrate (Lulo) and in the other two recognized cell lines has not been comparatively assessed. METHODS: Vero, C6/36, and Lulo cell lines were infected with DENV, YFV, and CHIKV. The viral progeny was quantified through plaque assays and quantitative reverse transcription-polymerase chain reaction, while for DENV2, the findings were confirmed by immunofluorescence antibody assay. RESULTS: The higher DENV2 titer (from multiplicity of infection 0.001) was obtained on day four post-infection in C6/36 and on day six in Vero cells, while the Lulo cell line was almost impossible to infect under the same conditions. However, C6/36 showed the highest values of viral RNA production compared to Vero cells, while the quantification of the viral RNA in Lulo cells showed high levels of viral genomes, which had no correlation to the infectious viral particles. CONCLUSIONS: C6/36 was the most efficient cell line in the alpha and flavivirus production, followed by Vero cells. Thus, Lulo cells may be a useful substrate to study the mechanisms by which cells evade viral replication.


Subject(s)
Animals , Virus Replication/physiology , Yellow fever virus/physiology , Chikungunya virus/physiology , Dengue Virus/physiology , Insecta/virology , Time Factors , Vero Cells , Chlorocebus aethiops , Cricetinae , Reverse Transcriptase Polymerase Chain Reaction
10.
Article in English | WPRIM | ID: wpr-758933

ABSTRACT

The recent emergence and re-emergence of porcine epidemic diarrhea virus (PEDV) underscore the urgent need for the development of novel, safe, and effective vaccines against the prevailing strain. In this study, we generated a cold-adapted live attenuated vaccine candidate (Aram-P29-CA) by short-term passage of a virulent PEDV isolate at successively lower temperatures in Vero cells. Whole genome sequencing identified 12 amino acid changes in the cold-adapted strain with no insertions and deletions throughout the genome. Animal inoculation experiments confirmed the attenuated phenotype of Aram-P29-CA virus in the natural host. Pregnant sows were orally administered P29-CA live vaccines two doses at 2-week intervals prior to parturition, and the newborn piglets were challenged with the parental virus. The oral homologous prime-boost vaccination of P29-CA significantly improved the survival rate of the piglets and notably mitigated the severity of diarrhea and PEDV fecal shedding after the challenge. Furthermore, strong antibody responses to PEDV were detected in the sera and colostrum of immunized sows and in the sera of their offspring. These results demonstrated that the cold-adapted attenuated virus can be used as a live vaccine in maternal vaccination strategies to provide durable lactogenic immunity and confer passive protection to litters against PEDV.


Subject(s)
Animals , Antibody Formation , Colostrum , Diarrhea , Genome , Genotype , Humans , Infant, Newborn , Parents , Parturition , Phenotype , Porcine epidemic diarrhea virus , Survival Rate , Vaccination , Vaccines , Vero Cells
11.
Article in English | WPRIM | ID: wpr-773410

ABSTRACT

OBJECTIVE@#To investigate the mechanisms underlying ozone-induced inactivation of poliovirus type 1 (PV1).@*METHODS@#We used cell culture, long-overlapping RT-PCR, and spot hybridization assays to verify and accurately locate the sites of action of ozone that cause PV1 inactivation. We also employed recombinant viral genome RNA infection models to confirm our observations.@*RESULTS@#Our results indicated that ozone inactivated PV1 primarily by disrupting the 5'-non-coding region (5'-NCR) of the PV1 genome. Further study revealed that ozone specifically damaged the 80-124 nucleotide (nt) region in the 5'-NCR. Recombinant viral genome RNA infection models confirmed that PV1 lacking this region was non-infectious.@*CONCLUSION@#In this study, we not only elucidated the mechanisms by which ozone induces PV1 inactivation but also determined that the 80-124 nt region in the 5'-NCR is targeted by ozone to achieve this inactivation.


Subject(s)
5' Untranslated Regions , Animals , Chlorocebus aethiops , Genome, Viral , Oxidants, Photochemical , Pharmacology , Ozone , Pharmacology , Poliovirus , Vero Cells , Virus Inactivation
12.
Article in Chinese | WPRIM | ID: wpr-813038

ABSTRACT

To explore the antiviral activity of nano-realgar against herpes simplex virus Type II (HSV-2) in vitro.
 Methods: Acyclovir (ACV) as a positive control, the cytotoxicity of nano-realgar at different concentrations (including 200.00, 150.00, 100.00, 50.00, 25.00, 12.50, 6.25, 3.13, 1.54, 0.78, 0.39 and 0 mg/L) on normal Vero cells were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. HSV-2 virus titer was determined by plaque assay, and the Vero cells model of HSV-2 infection was established. Subsequently, the antiviral effects of nano-realgar at different concentrations (including 20.00, 10.00, 5.00, 2.50, 1.25, 0.63, 0.31, 0.15, 0.08, 0.04 and 0 mg/L) on infected cells model were evaluated by the observation of cytopathic effect (CPE) and MTT method under the 3 modes including pre-treatment, treatment and direct inactivation.
 Results: The 50% cytotoxic concentration (CC50) of nano-realgar on Vero cells was 37.15 mg/L. The titer of HSV-2 was 7.30 log PFUs/mL. In the 3 modes, the half-maximal effective concentration (EC50) of nano-realgar on HSV-2 infected Vero cells were 0.13, 1.80 and 0.52 mg/L, and the corresponding therapeutic index (TI) were 285.77, 20.64, 71.44, respectively. The TI value of nano-realgar on pre-treatment mode was higher than that of nano-realgar on treatment and direct inactivation modes.
 Conclusion: Nano-realgar can play a good anti-HSV-2 activity in the 3 modes (pre-treatment, treatment and direct inactivation), and the anti-HSV-2 efficacy of nano-realgar on pre-treatment mode is better than that of nano-realagr on other 2 modes.


Subject(s)
Animals , Antiviral Agents , Arsenicals , Chlorocebus aethiops , Herpesvirus 1, Human , Herpesvirus 2, Human , Sulfides , Vero Cells
13.
Mem. Inst. Oswaldo Cruz ; 113(4): e170332, 2018. graf
Article in English | LILACS | ID: biblio-894914

ABSTRACT

BACKGROUND Trypanosoma cruzi is a protozoan parasite and an etiological agent of Chagas disease. There is a wide variability in the clinical outcome of its infection, ranging from asymptomatic individuals to those with chronic fatal mega syndromes. Both parasite and host factors, as well as their interplay, are thought to be involved in the process. OBJECTIVES To evaluate the resistance to complement-mediated killing in two T. cruzi TcI strains with differential virulence and the subsequent effect on their infectivity in mammalian cells. METHODS Tissue-culture derived trypomastigotes of both strains were incubated in guinea pig serum and subjected to flow cytometry in order to determine their viability and complement activations. Trypomastigotes were also incubated on host cells monolayers in the presence of serum, and infectivity was evaluated under different conditions of complement pathway inhibition. Relative expression of the main parasite-specific complement receptors between the two strains was assessed by quantitative real-time polymerase chain reaction. FINDINGS In this work, we showed that two TcI strains, one with lower virulence (Ninoa) compared to the other (Qro), differ in their resistance to the lytic activity of complement system, hence causing a compromised ability of Ninoa strain to invade mammalian cells. These results correlate with the three-fold lower messenger RNA (mRNA) levels of complement regulatory protein (CRP), trypomastigote-decay acceleration factor (T-DAF), and complement C2 receptor inhibitor trispanning (CRIT) in Ninoa compared to those in Qro. On the other hand, calreticulin (CRT) mRNA and surface protein levels were higher in Ninoa strain and promoted its infectivity when the lectin pathway of the complement system was inhibited. MAIN CONCLUSIONS This work suggests the complex interplay of CRP, T-DAF, CRIT, and CRT, and the diagnostic value of mRNA levels in the assessment of virulence potential of T. cruzi strains, particularly when dealing with isolates with similar genetic background.


Subject(s)
Humans , Chlorocebus aethiops , Chagas Disease/parasitology , Antigens, Protozoan/analysis , Vero Cells , Blotting, Western
14.
Article in English | WPRIM | ID: wpr-758777

ABSTRACT

Outbreaks of porcine epidemic diarrhea (PED) have resulted in significant economic losses in the swine industry, and another PED outbreak occurred in 2014 in Korea. Isolating and culturing PED virus (PEDV) allow investigations into its pathogenesis and the development of vaccines and diagnostic assays. In this study, we successfully isolated two PEDV isolates (QIAP1401 and QIAP1402) from naturally infected piglets at Jeju-do, Korea. Viral propagation was confirmed in Vero cells based on cytopathic effect, immunofluorescence assay, reverse transcription-polymerase chain reaction, and electron microscopic analyses. The QIAP401 isolate propagated well in Vero cells for 70 passages, with titers of 10(6.5) to 10(7.0) 50% tissue culture infectious dose/mL, which increased gradually with passaging. The nucleotide and amino acid sequences of the QIAP1401 isolate were determined and compared with those of other PEDV isolates. The QIAP1401 isolate was determined to be closely related to the USA/Minnesota271/2014 strain (> 99.9% nucleotide similarity) that was isolated in the USA in 2014. Phylogenetic analysis based on several PEDV genes suggested that a new PEDV variant is circulating in the Korean swine industry, with 93.08% similarity to the SM98 strain isolated in 1998. In addition, the QIAP1401 strain showed strong virulence in 3-day-old piglets and 11-week-old growing pigs.


Subject(s)
Amino Acid Sequence , Diarrhea , Disease Outbreaks , Fluorescent Antibody Technique , Korea , Porcine epidemic diarrhea virus , Swine , Vaccines , Vero Cells , Virulence
15.
Article in English | WPRIM | ID: wpr-739636

ABSTRACT

PURPOSE: The first aim of this study was to develop a novel inactivated porcine epidemic diarrhea virus (PEDV) vaccine using the recently isolated Korean PEDV QIAP1401 strain and to evaluate its protective efficacy in growing pigs. The second was to determine the optimum adjuvant formulation of the inactivated PEDV vaccine that induces protection against viral challenge. MATERIALS AND METHODS: To generate high titers of infectious PEDV, the QIAP1401 isolate was passaged in Vero cells. The experimental vaccines were prepared from a binary ethyleneimine-inactivated QIAP1401 strain passaged sequentially 70 times (QIAP1401-p70), formulated with four commercial adjuvants, and administered twice intramuscularly to growing pigs. Challenge studies using a virulent homologous strain of PEDV QIAP1401-p11, which was passaged 11 times after isolation, were performed to assess protection against disease progression and viral shedding during the 15-day observation period. The vaccine-induced antibody responses were measured in serum samples collected at predetermined time points by indirect enzyme-linked immunosorbent assay and virus neutralization test. RESULTS: The QIAP1401-p70 strain had 42 amino acid (aa) mutations, including a 25 aa deletion, and was selected as the inactivated PEDV vaccine candidate. Although none of the pigs that received the experimental vaccines were completely protected against subsequent viral challenge, they exhibited a significantly higher immune response than did non-vaccinated control pigs. Among the vaccine groups, the highest antibody responses were observed in the pigs that received an oil-based multiphasic water/oil/water (W/O/W) emulsion adjuvanted vaccine, which delayed the onset of clinical symptoms and viral shedding. CONCLUSION: A novel inactivated PEDV vaccine formulated with a W/O/W emulsion adjuvant was both immunogenic and protective against viral challenge.


Subject(s)
Antibody Formation , Disease Progression , Enzyme-Linked Immunosorbent Assay , Neutralization Tests , Porcine epidemic diarrhea virus , Swine , Vaccines , Vero Cells , Virus Shedding
16.
Article in English | WPRIM | ID: wpr-741522

ABSTRACT

Canine adenovirus type 2 (CAV-2) infection results in significant respiratory illness in dogs. Isolating and culturing CAV-2 allows for investigations into its pathogenesis and the development of vaccines and diagnostic assays. In this study, we successfully isolated a virus from a naturally infected dog in Gyeonggi-do, Korea. The virus was propagated in Madin-Darby canine kidney (MDCK) and Vero cells and showed a specific cytopathic morphology that appeared similar to a bunch of grapes. The virus was first confirmed as CAV-2 based on these cytopathic effects, an immunofluorescence assay, hemagglutination assay, and electron microscopy. The viral titer of the isolate designated APQA1601 reached 10(6.5) 50% tissue culture infections dose per mL in MDCK cells and exhibited no hemagglutination units with erythrocytes from guinea pig. The virus was also confirmed by polymerase chain reaction and next-generation sequencing. The APQA1601 strain had the highest similarity (~99.9%) with the Toronto A26/61 strain, which was isolated in Canada in 1976 when the nucleotide sequences of the full genome of the APQA1601 strain were compared with those of other CAV strains. Isolating CAV-2 will help elucidate the biological properties of CAV-2 circulating in Korean dogs.


Subject(s)
Adenoviruses, Canine , Animals , Base Sequence , Canada , Dogs , Erythrocytes , Fluorescent Antibody Technique , Genome , Guinea Pigs , Hemagglutination , Kidney , Korea , Madin Darby Canine Kidney Cells , Microscopy, Electron , Polymerase Chain Reaction , Vaccines , Vero Cells , Vitis
17.
Braz. j. microbiol ; 48(4): 764-768, Oct.-Dec. 2017. graf
Article in English | LILACS | ID: biblio-889184

ABSTRACT

ABSTRACT Clostridium perfringens is the causative agent for necrotic enteritis. It secretes the major virulence factors, and α- and NetB-toxins that are responsible for intestinal lesions. The TpeL toxin affects cell morphology by producing myonecrosis, but its role in the pathogenesis of necrotic enteritis is unclear. In this study, the presence of netB and tpeL genes in C. perfringens type A strains isolated from chickens with necrotic enteritis, their cytotoxic effects and role in adhesion and invasion of epithelial cells were evaluated. Six (27.3%) of the 22 C. perfringens type A strains were harboring the tpeL gene and produced morphological alterations in Vero cells after 6 h of incubation. Strains tpeL (-) induced strong cell rounding after 6 h of incubation and produced cell enlargement. None of the 22 strains harbored netB gene. All the six tpeL (+) gene strains were able to adhere to HEp-2 cells; however, only four of them (66.6%) were invasive. Thus, these results suggest that the presence of tpeL gene or TpeL toxin might be required for the adherence of bacteria to HEp-2 cells; however, it could not have any role in the invasion process.


Subject(s)
Humans , Animals , Poultry Diseases/microbiology , Bacterial Adhesion , Clostridium Infections/microbiology , Clostridium Infections/veterinary , Clostridium perfringens/physiology , Epithelial Cells/microbiology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Vero Cells , Chlorocebus aethiops , Chickens , Clostridium perfringens/isolation & purification , Clostridium perfringens/genetics
18.
An. acad. bras. ciênc ; 89(4): 3111-3121, Oct.-Dec. 2017. tab, graf
Article in English | LILACS | ID: biblio-886824

ABSTRACT

ABSTRACT With the aim of introducing permanent prostheses with main properties equivalent to cortical human bone, Ti-diamond composites were processed through powder metallurgy. Grade 1 titanium and mixtures of Ti powder with 2%, 5% and 10 wt% diamond were compacted at 100MPa, and then sintered at 1250°C/2hr/10-6mbar. Sintered samples were studied in the point of view of their microstructures, structures, yield strength and elastic modulus. The results showed that the best addition of diamonds was 2 wt%, which led to a uniform porosity, yield strength of 370MPa and elastic modulus of 13.9 GPa. Samples of Ti and Ti-2% diamond were subjected to in vitro cytotoxicity test, using cultures of VERO cells, and it resulted in a biocompatible and nontoxic composite material.


Subject(s)
Humans , Animals , Titanium/analysis , Biocompatible Materials/analysis , Materials Testing/methods , Diamond/analysis , Surface Properties , Tensile Strength , Vero Cells , Chlorocebus aethiops , Porosity
19.
Mem. Inst. Oswaldo Cruz ; 112(2): 131-139, Feb. 2017. tab, graf
Article in English | LILACS | ID: biblio-841764

ABSTRACT

BACKGROUND Recent studies showed that essential oils from different pepper species (Piper spp.) have promising leishmanicidal and trypanocidal activities. OBJECTIVES In search for natural compounds against Trypanosoma cruzi, different forms of the parasite were incubated for 24 h at 28ºC or 4ºC with Piper aduncum essential oil (PaEO) or its main constituents linalool and nerolidol. METHODS PaEO chemical composition was obtained by GC-MS. Drug activity assays were based on cell counting, MTT data or infection index values. The effect of PaEO on the T. cruzi cell cycle and mitochondrial membrane potential was evaluated by flow cytometry. FINDINGS PaEO was effective against cell-derived (IC50/24 h: 2.8 μg/mL) and metacyclic (IC50/24 h: 12.1 μg/mL) trypomastigotes, as well as intracellular amastigotes (IC50/24 h: 9 μg/mL). At 4ºC - the temperature of red blood cells (RBCs) storage in blood banks - cell-derived trypomastigotes were more sensitive to PaEO (IC50/24 h = 3.8 μg/mL) than to gentian violet (IC50/24 h = 24.7 mg/mL). Cytotoxicity assays using Vero cells (37ºC) and RBCs (4ºC) showed that PaEO has increased selectivity for cell-derived trypomastigotes. Flow cytometry analysis showed that PaEO does not affect the cell cycle of T. cruzi epimastigotes, but decreases their mitochondrial membrane potential. GC-MS data identified nerolidol and linalool as major components of PaEO, and linalool had trypanocidal effect (IC50/24 h: 306 ng/mL) at 4ºC. MAIN CONCLUSION The trypanocidal effect of PaEO is likely due to the presence of linalool, which may represent an interesting candidate for use in the treatment of potentially contaminated RBCs bags at low temperature.


Subject(s)
Animals , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/drug effects , Biological Assay , Oils, Volatile/pharmacology , Piper/chemistry , Vero Cells , Microbial Sensitivity Tests , Chlorocebus aethiops , Cold Temperature , Monoterpenes/pharmacology , Gas Chromatography-Mass Spectrometry
20.
Article in English | WPRIM | ID: wpr-67783

ABSTRACT

BACKGROUND/AIMS: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by severe fever with thrombocytopenia syndrome virus (SFTSV), a novel bunyavirus. As yet, there is no effective antiviral therapy for SFTS. Ribavirin is a broad-spectrum antiviral agent, which has been tried for treatment of SFTS. In this study, antiviral activity of ribavirin against SFTSV has been investigated. METHODS: Vero cell-grown SFTSV strain Gangwon/Korea/2012 was treated with ribavirin at various concentrations. Antiviral activity of ribavirin was evaluated by inhibition of the SFTSV cytopathic effect in Vero cells and quantification of viral RNA load in culture supernatant using one-step real-time reverse transcription polymerase chain reaction. Cytotoxicity of ribavirin was determined by a tetrazolium-based colorimetric method. RESULTS: Ribavirin reduced SFTSV titers in a dose-dependent manner, with a half-maximal inhibitory concentration ranged from 3.69 to 8.72 μg/mL. Cytopathic effects were reduced as ribavirin concentration increased. No significant cytotoxicity was detected at ribavirin concentrations of ≤ 31.3 μg/mL. CONCLUSIONS: Ribavirin exhibited inhibitory activity against SFTSV replication in vitro, which suggests that ribavirin can be used as a potential antiviral agent for SFTS.


Subject(s)
Antiviral Agents , Bunyaviridae Infections , Communicable Diseases, Emerging , Fever , In Vitro Techniques , Methods , Orthobunyavirus , Phlebovirus , Polymerase Chain Reaction , Reverse Transcription , Ribavirin , RNA, Viral , Thrombocytopenia , Vero Cells
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