The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Víctor Romanowski - One of the best experts on this subject based on the ideXlab platform.
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Junin Virus induces autophagy in human a549 cells
PLOS ONE, 2019Co-Authors: Maria Laura Anabella Perez Vidakovics, Agustin Enrique Ure, Víctor Romanowski, Paula Nazarena Arrias, Ricardo M GomezAbstract:Autophagy, a highly regulated degradative process that promotes cellular homeostasis, is increasingly recognised as a fundamental component of the cellular response against viral infection. In this study, we investigated the role of autophagy during Junin Virus (JUNV) multiplication using human A549 cells. We found that JUNV infection induces an increment of the LC3-II/LC3-I ratio, an accumulation of punctate pattern in RFP-LC3-transfected cells and the colocalisation of viral nucleoprotein and LC3 protein, suggesting autophagosome formation. JUNV infection also induced the degradation of the autophagy receptor p62, suggesting that complete autophagic flux was triggered. In addition, we showed that inhibition of autophagy with bafilomycin A1 or 3-methyladenine significantly reduces viral multiplication. Moreover, viral yield was increased when autophagy was induced using rapamycin. Furthermore, JUNV infection induced the colocalisation of p62, ATG16, RAB5, RAB7A and LAMP1 with the autophagosomal LC3 protein. That suggests that phagosomes undergo the maturation process during viral infection. Finally, we demonstrated that siRNA experiments targeting essential autophagy genes (ATG5, ATG7 and Beclin 1) reduce viral protein synthesis and viral yield. Overall, our results indicate that JUNV activates host autophagy machinery enhancing its multiplication.
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astrocyte response to Junin Virus infection
Neuroscience Letters, 2008Co-Authors: Roberto Gabriel Pozner, Mirta Schattner, Víctor Romanowski, Soledad Collado, Carolina Jaquenod De Giusti, Agustin Enrique Ure, Marina E Biedma, Ricardo M GomezAbstract:In a previous study of experimental murine encephalitis induced by Junin Virus (JV), an arenaVirus, we showed increased expression of iNOS by unidentified cells, concomitant with the astrocyte reaction. The specific inhibition of iNOS was associated with greater mortality but lower astrocytosis, suggesting that the protective role of nitric oxide (NO) synthesized by iNOS was related to enhanced astrocyte activation, representing a beneficial cellular response to Virus-induced central nervous system damage. In the present work, cultured astrocytes were used to study whether JV infection could trigger iNOS expression and assess its eventual relationship with viral replication, glial fibrilary acidic protein (GFAP) expression levels and the presence of apoptosis. We found that JV infection of astrocytes did not induce apoptosis but produced both increased iNOS synthesis, detected by immunocytochemistry and fluorescence activated cell sorting (FACS) analysis, and increased NO, which was indirectly measured by nitrite/nitrate levels. These changes occurred early relative to the increases in GFAP expression, as detected by immunocytochemistry, FACS analysis and RT-PCR. The fact that iNOS inhibition abolished enhanced GFAP expression in infected monolayers suggests that NO was directly involved. In addition, iNOS inhibition enhanced Virus replication. Together with data from confocal microscopy, these results suggest that JV induces iNOS expression in infected astrocytes and that the resulting NO has an important role both in reducing viral replication and in enhancing subsequent astrocyte activation.
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Molecular characterization of attenuated Junin Virus strains
Journal of General Virology, 1997Co-Authors: Víctor Romanowski, Pablo Daniel Ghiringhelli, César G. Albariño, Mariel PiboulAbstract:The Junin Virus strain Candid #1 was developed as a live attenuated vaccine for Argentine haemorrhagic fever. In this paper we report the nucleotide sequences of S RNA of Candid #1 and its more virulent ancestors XJ#44 and XJ (prototype). Their relationship to Junin Virus wild-type MC2 strain and other closely and distantly related arenaViruses was also examined. Comparisons of the nucleotide and amino acid sequences of N and GPC genes from Candid #1 and its progenitor strains revealed some changes that are unique to the vaccine strain. These changes could be provisionally associated with the attenuated phenotype.
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The Glycoprotein Precursor Gene of the Attenuated Junin Virus Vaccine Strain (Candid #1)
The American journal of tropical medicine and hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
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the glycoprotein precursor gene of the attenuated Junin Virus vaccine strain candid 1
American Journal of Tropical Medicine and Hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
Pablo Daniel Ghiringhelli - One of the best experts on this subject based on the ideXlab platform.
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Molecular characterization of attenuated Junin Virus strains
Journal of General Virology, 1997Co-Authors: Víctor Romanowski, Pablo Daniel Ghiringhelli, César G. Albariño, Mariel PiboulAbstract:The Junin Virus strain Candid #1 was developed as a live attenuated vaccine for Argentine haemorrhagic fever. In this paper we report the nucleotide sequences of S RNA of Candid #1 and its more virulent ancestors XJ#44 and XJ (prototype). Their relationship to Junin Virus wild-type MC2 strain and other closely and distantly related arenaViruses was also examined. Comparisons of the nucleotide and amino acid sequences of N and GPC genes from Candid #1 and its progenitor strains revealed some changes that are unique to the vaccine strain. These changes could be provisionally associated with the attenuated phenotype.
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The Glycoprotein Precursor Gene of the Attenuated Junin Virus Vaccine Strain (Candid #1)
The American journal of tropical medicine and hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
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the glycoprotein precursor gene of the attenuated Junin Virus vaccine strain candid 1
American Journal of Tropical Medicine and Hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
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Molecular organization of Junin Virus S RNA: complete nucleotide sequence, relationship with other members of the Arenaviridae and unusual secondary structures.
Journal of General Virology, 1991Co-Authors: Pablo Daniel Ghiringhelli, R V Rivera-pomar, M E Lozano, Oscar Grau, Víctor RomanowskiAbstract:In this study, overlapping cDNA clones covering the entire S RNA molecule of Junin Virus, an arenaVirus that causes Argentine haemorrhagic fever, were generated. The complete sequence of this 3400 nucleotide RNA was determined using the dideoxynucleotide chain termination method. The nucleocapsid protein (N) and the glycoprotein precursor (GPC) genes were identified as two non-overlapping open reading frames of opposite polarity, encoding primary translation products of 564 and 481 amino acids, respectively. Intracellular processing of the latter yields the glycoproteins found in the viral envelope. Comparison of the Junin Virus N protein with the homologous proteins of other arenaViruses indicated that amino acid sequences are conserved, the identity ranging from 46 to 76%. The N-terminal half of GPC exhibits an even higher degree of conservation (54 to 82%), whereas the C-terminal half is less conserved (21 to 50%). In all comparisons the highest level of amino acid sequence identity was seen when Junin Virus and Tacaribe Virus sequences were aligned. The nucleotide sequence at the 5′ end of Junin Virus S RNA is not identical to that determined of the other sequenced arenaViruses. However, it is complementary to the 3′-terminal sequences and may form a very stable panhandle structure (ΔG -242.7 kJ/mol) involving the complete non-coding regions upstream from both the N and GPC genes. In addition, a distinct secondary structure was identified in the intergenic region, downstream from the coding sequences; Junin Virus S RNA shows a potential secondary structure consisting of two hairpin loops (ΔG -163.2 and -239.3 kJ/mol) instead of the single hairpin loop that is usually found in other arenaViruses. The analysis of the arenaVirus S RNA nucleotide sequences and their encoded products is discussed in relation to structure and function.
Mariel Piboul - One of the best experts on this subject based on the ideXlab platform.
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Molecular characterization of attenuated Junin Virus strains
Journal of General Virology, 1997Co-Authors: Víctor Romanowski, Pablo Daniel Ghiringhelli, César G. Albariño, Mariel PiboulAbstract:The Junin Virus strain Candid #1 was developed as a live attenuated vaccine for Argentine haemorrhagic fever. In this paper we report the nucleotide sequences of S RNA of Candid #1 and its more virulent ancestors XJ#44 and XJ (prototype). Their relationship to Junin Virus wild-type MC2 strain and other closely and distantly related arenaViruses was also examined. Comparisons of the nucleotide and amino acid sequences of N and GPC genes from Candid #1 and its progenitor strains revealed some changes that are unique to the vaccine strain. These changes could be provisionally associated with the attenuated phenotype.
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The Glycoprotein Precursor Gene of the Attenuated Junin Virus Vaccine Strain (Candid #1)
The American journal of tropical medicine and hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
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the glycoprotein precursor gene of the attenuated Junin Virus vaccine strain candid 1
American Journal of Tropical Medicine and Hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
Tomas Kirchhausen - One of the best experts on this subject based on the ideXlab platform.
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Superinfection exclusion is absent during acute Junin Virus infection of Vero and A549 cells
Scientific Reports, 2015Co-Authors: Raphaël Gaudin, Tomas KirchhausenAbstract:Many Viruses have evolved strategies of so-called “superinfection exclusion” to prevent re-infection of a cell that the same Virus has already infected. Although Old World arenaVirus infection results in down-regulation of its viral receptor and thus superinfection exclusion, whether New World arenaViruses have evolved such a mechanism remains unclear. Here we show that acute infection by the New World Junin Virus (JUNV) failed to down-regulate the transferrin receptor and did not induce superinfection exclusion. We observed that Vero cells infected by a first round of JUNV ( Candid1 strain) preserve an ability to internalize new incoming JUNV particles that is comparable to that of non-infected cells. Moreover, we developed a dual infection assay with the wild-type Candid1 JUNV and a recombinant JUNV-GFP Virus to discriminate between first and second infections at the transcriptional and translational levels. We found that Vero and A549 cells already infected by JUNV were fully competent to transcribe viral RNA from a second round of infection. Furthermore, flow cytometry analysis of viral protein expression indicated that viral translation was normal, regardless of whether cells were previously infected or not. We conclude that in acutely infected cells, Junin Virus lacks a superinfection exclusion mechanism.
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superinfection exclusion is absent during acute Junin Virus infection of vero and a549 cells
Scientific Reports, 2015Co-Authors: Raphaël Gaudin, Tomas KirchhausenAbstract:Many Viruses have evolved strategies of so-called “superinfection exclusion” to prevent re-infection of a cell that the same Virus has already infected. Although Old World arenaVirus infection results in down-regulation of its viral receptor and thus superinfection exclusion, whether New World arenaViruses have evolved such a mechanism remains unclear. Here we show that acute infection by the New World Junin Virus (JUNV) failed to down-regulate the transferrin receptor and did not induce superinfection exclusion. We observed that Vero cells infected by a first round of JUNV (Candid1 strain) preserve an ability to internalize new incoming JUNV particles that is comparable to that of non-infected cells. Moreover, we developed a dual infection assay with the wild-type Candid1 JUNV and a recombinant JUNV-GFP Virus to discriminate between first and second infections at the transcriptional and translational levels. We found that Vero and A549 cells already infected by JUNV were fully competent to transcribe viral RNA from a second round of infection. Furthermore, flow cytometry analysis of viral protein expression indicated that viral translation was normal, regardless of whether cells were previously infected or not. We conclude that in acutely infected cells, Junin Virus lacks a superinfection exclusion mechanism. ArenaViruses are enveloped Viruses with two segments of an ambisense single-stranded RNA genome. Some of these Viruses cause hemorrhagic fever with poor prognoses in humans, including the New World (NW) arenaVirus (clade B) Junin Virus (JUNV), which is responsible for Argentine hemorrhagic
César G. Albariño - One of the best experts on this subject based on the ideXlab platform.
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Molecular characterization of attenuated Junin Virus strains
Journal of General Virology, 1997Co-Authors: Víctor Romanowski, Pablo Daniel Ghiringhelli, César G. Albariño, Mariel PiboulAbstract:The Junin Virus strain Candid #1 was developed as a live attenuated vaccine for Argentine haemorrhagic fever. In this paper we report the nucleotide sequences of S RNA of Candid #1 and its more virulent ancestors XJ#44 and XJ (prototype). Their relationship to Junin Virus wild-type MC2 strain and other closely and distantly related arenaViruses was also examined. Comparisons of the nucleotide and amino acid sequences of N and GPC genes from Candid #1 and its progenitor strains revealed some changes that are unique to the vaccine strain. These changes could be provisionally associated with the attenuated phenotype.
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The Glycoprotein Precursor Gene of the Attenuated Junin Virus Vaccine Strain (Candid #1)
The American journal of tropical medicine and hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
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the glycoprotein precursor gene of the attenuated Junin Virus vaccine strain candid 1
American Journal of Tropical Medicine and Hygiene, 1997Co-Authors: Pablo Daniel Ghiringhelli, César G. Albariño, Mariel Piboul, Víctor RomanowskiAbstract:A live attenuated Virus vaccine has been recently developed to prevent Argentine hemorrhagic fever. In this paper, we report the nucleotide sequence of the glycoprotein precursor gene (GPC) of the Junin Virus vaccine strain (Candid #1) and its flanking untranslated regions. The untranslated regions flanking the GPC genes of different arenaViruses are variable in length, sequence, and secondary structure. However, when this highly attenuated Junin Virus strain is compared with the MC2 strain, which is of intermediate virulence, one nucleotide insertion and four nucleotide substitutions are found at positions that do not affect the predicted secondary structure. When Candid #1 and MC2 RNAs are compared, the nucleotide sequence changes in the GPC open reading frame are concentrated in the amino-proximal and the carboxy-proximal regions. The comparison of the amino acid residues shows that the major changes are located in the amino-proximal region of the GPC.
