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C F Arias

Publications and source records attributed to C F Arias.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Correlation between serotype and electrophoretype of rotaviruses isolated in 2 Mexican populations].

In order to study the correlation between the serotype specificity and the genomic RNA electrophoretic pattern (electropherotype) of human rotavirus (HRV) strains, we analyzed the electropherotypes of 54 HRV that had been collected during a four year study in Mexico, and whose serotypes had been previously determined. We detected 17 different electropherotypes, four in association with serotype G1, two with serotype G2, six with serotype G3, and five with serotype G4. There were no viruses with the same electropherotype having a different serotype. The variations in RNA electrophoretic migration were greater between viruses belonging to different serotypes than between viruses of the same serotype. It is of note that the relative separation of RNA segments 7 and 9 remained constant among viruses of the same serotype. Electropherotyping might have a serotype predictive value for rotavirus specimens lacking the virion outer capsid.

Electrophoresis, Polyacrylamide Gel↗
PubMed1992

Genomic rearrangements in human rotavirus strain Wa; analysis of rearranged RNA segment 7.

Two rotavirus variants containing genomic rearrangements were isolated from human rotavirus strain Wa. In one variant (H5) the rearrangement involves the RNA segment 5, while in the other variant (H57) two genes, 5 and 7 are rearranged. The rearranged genes are composed exclusively of sequences from the genes they substitute. Sequence analysis of the rearranged segment 7 indicated that it is a partial duplication of the wild type gene, in a head-to-tail orientation.

Base Sequence↗
PubMed1991

The amino-terminal half of rotavirus SA114fM VP4 protein contains a hemagglutination domain and primes for neutralizing antibodies to the virus.

We have previously reported the synthesis in Escherichia coli of polypeptide MS2-VP8', which contains the amino-terminal half of the SA114fM VP4 protein fused to MS2 bacteriophage polymerase sequences (C. F. Arias, M. Lizano, and S. López, J. Gen. Virol. 68:633-642, 1987). In this work we have synthesized the carboxy-terminal half of the VP4 protein also fused to the MS2 polymerase. This protein, designated MS2-VP5', was recognized by sera to the complete virion and was able to induce antibodies to the virus when administered to mice; however, these antibodies had no neutralizing activity. The two chimeric polypeptides were tested for their ability to agglutinate erythrocytes and to prime the immune system of mice. Bacterial lysates enriched for the MS2-VP8' hybrid polypeptide, but not those enriched for the MS2-VP5' protein or those containing proteins from the host E. coli strain, had hemagglutinating activity. This hemagglutination was inhibited by sera to SA114fM rotavirus. In addition, a single dose of the MS2-VP8' polypeptide was able to prime the immune system of mice for an augmented neutralizing antibody response when the animals were subsequently immunized with purified SA114fM virus.

Amino Acid Sequence↗
PubMed1991

Rotavirus YM gene 4: analysis of its deduced amino acid sequence and prediction of the secondary structure of the VP4 protein.

We have determined the complete nucleotide sequence of the VP4 gene of porcine rotavirus YM. It is 2,362 nucleotides long, with a single open reading frame coding for a protein of 776 amino acids. A phylogenetic tree was derived from the deduced YM VP4 amino acid sequence and 18 other available VP4 sequences of rotavirus strains belonging to different serotypes and isolated from different animal species. In this tree, VP4 proteins were grouped by the hosts that the corresponding viruses infect rather than by the serotypes they belong to, suggesting that this protein is involved in the host specificity of the viruses. In an attempt to predict the secondary structure of the VP4 protein, we selected the more divergent VP4 sequences and made a secondary structure analysis of each protein. In spite of variations within the individual structures predicted, there was a general structural pattern which suggested the existence of at least two different domains. One, comprising the amino-terminal 63% of the protein, is predicted to be a possible globular domain rich in beta-strands alternated with turns and coils. The second domain, represented by the remaining, carboxy-terminal part of VP4, is rich in long stretches of alpha-helix, one of which, 63 amino acids long, has heptad repeats resembling those found in proteins known to form alpha-helical coiled-coils. The predicted secondary structure correlates well with the available data on the protein accessibility delineated by immunological and biochemical findings and with the spike structure of the protein, which has been determined by cryoelectron microscopy.

Amino Acid Sequence↗
PubMed1990

Diversity of rotavirus serotypes in Mexican infants with gastroenteritis.

One hundred thirty-two stool specimens from infants with rotavirus gastroenteritis hospitalized in two Mexican cities (Mexico City and Mérida) were examined by serotype- and subgroup-specific enzyme immunoassays. Among them, 38 (29%) were serotype 1, 15 (11%) were serotype 2, 13 (10%) were serotype 3, 22 (17%) were serotype 4, none was serotype 5 or 6, and 44 (33%) could not be serotyped. By subgrouping, 121 specimens were characterized as follows: 24 (18%) were subgroup 1, 97 (74%) were subgroup 2, and none had both subgroup specificities. While serotype 1 rotavirus predominated in the Mexico City area for 4 consecutive years (1984 to 1987), serotype 4 predominated in Mérida during the single epidemic season studied (1985). These data demonstrate that all four primary human rotavirus serotypes circulated in Mexico, with serotype 1 being the most prevalent. The seroneutralization responses of 14 of the 22 patients infected with serotype 4 strains had been previously studied. Of these 14 infants, 11 appeared to have primary infections, as indicated by absence of neutralizing antibodies in the acute-phase sera and their young age (8 months on average) at the time of illness. Seven patients seroresponded to serotypes 1 and 4; two seroresponded to serotypes 1, 3, and 4; three seroresponded to serotype 1; and two had low-level seroresponses to serotype 3 or 4. These data indicate that heterotypic neutralizing antibody responses occur frequently following infection with serotype 4 rotaviruses.

Antibodies, Monoclonal↗
PubMed1989

Naturally occurring serotype 2/subgroup II rotavirus reassortants in northern Brazil.

Nine serotype 2 human rotavirus strains were isolated in a community-based longitudinal study in Northern Brazil. Five of these strains had a 'long' RNA electrophoretic pattern and all five strains were determined to belong to subgroup II by ELISA assay, in contrast to properties common to serotype 2 human rotaviruses previously characterized. Hybridization studies of one of these unusual strains with 32P-labelled mRNAs derived from the prototype human strains Wa (serotype 1, subgroup II) and S2 (serotype 2, subgroup I) suggested that it was generated by a reassortment event in nature, in which a subgroup II, 'long' electropherotype rotavirus exchanged its serotype-specific gene and gene number 10 for the equivalent genes from a serotype 2, 'short' electropherotype virus.

Brazil↗
PubMed1989

Further antigenic characterization of porcine rotavirus YM.

We recently reported that the serotype specificity of YM, a group A porcine rotavirus, is different from those of the previously established rotavirus serotypes, 1 to 6 (A. M. Ruiz, I. V. Lopez, S. Lopez, R. T. Espejo, and C. F. Arias, J. Virol. 62:4331-4336, 1988). Here we demonstrate by cross-neutralization studies that rotavirus YM is also antigenically distinct from prototype rotavirus strains of serotypes 7 (Ty1), 8 (69M), 9 (WI61), and 10 (B223). A comparison of the serotype-determining amino acid regions of the YM surface glycoprotein, VP7, with the reported homologous sequences of rotavirus strains Gottfried, 69M, B37, F45, and WI61 further supported the serotypic individuality of the rotavirus YM VP7 protein.

Amino Acid Sequence↗
PubMed1989

Priming for rotavirus neutralizing antibodies by a VP4 protein-derived synthetic peptide.

In the rotavirus SA11 surface protein VP4, the trypsin cleavage sites associated with the enhancement of infectivity are flanked by two amino acid regions that are highly conserved among different rotaviruses. We have tested the ability of synthetic peptides that mimic these two regions to induce and prime for a rotavirus neutralizing antibody response in mice. After the peptide immunization schedule, both peptides induced peptide antibodies, but neither was able to induce virus antibodies, as measured by an enzyme-linked immunosorbent assay or a neutralization assay. However, when the peptide-inoculated mice were subsequently injected with intact SA11 virus, a rapid and high neutralizing antibody response was observed in mice that had previously received the peptide comprising amino acids 220 to 233 of the VP4 protein. This neutralizing activity was serotype specific; however, this peptide was also able to efficiently prime the immune system of mice for a neutralizing antibody response to the heterotypic rotavirus ST3 when the ST3 virus was used for the secondary inoculation.

Amino Acid Sequence↗
PubMed1989

Comparative evaluation of the WHO and DAKOPATTS enzyme-linked immunoassay kits for rotavirus detection.

Faeces obtained from 1,163 children (including 66 newborn babies) were analysed in parallel for the presence of rotavirus particles using two enzyme-linked immunosorbent assay kits. The kits had been formulated by the WHO Collaborating Centre for Reference and Research on Rotavirus (WHO-ELISA kit) and by DAKOPATTS (DAKO-ELISA kit) to be suitable for use in laboratories in developing countries. The kits were evaluated in laboratories in Burma, Chile, India, Mexico, Pakistan, Sri Lanka and the United Kingdom. Comparison of the results obtained with the two kits indicated that the DAKO-ELISA had an overall sensitivity of 97% and a specificity of 97% relative to the WHO-ELISA. In individual laboratories the DAKO-ELISA (K349) kit had a sensitivity in the range 90-100%, and a specificity of 85-100%. The kit showed a sensitivity of 100% and a specificity of 98% in assays on faeces obtained from newborn babies. We conclude that the DAKO-ELISA is as sensitive and specific as the WHO-ELISA for the detection of rotavirus antigen in faeces.

Enzyme-Linked Immunosorbent Assay↗
PubMed1988

Molecular and antigenic characterization of porcine rotavirus YM, a possible new rotavirus serotype.

In 1983, we isolated a porcine rotavirus (strain YM) that was prevalent in several regions of Mexico, as judged by the frequency of its characteristic electropherotype. By a focus reduction neutralization test, rotavirus YM was clearly distinguished from prototype rotavirus strains belonging to serotypes 1 (Wa), 2 (S2), 3 (SA11), 4 (ST3), 5 (OSU), and 6 (NCDV). Minor, one-way cross-neutralization (1 to 5%) was observed when antisera to the various rotavirus strains were incubated with rotavirus YM. In addition, the YM virus was not neutralized by neutralizing monoclonal antibodies with specificity to serotypes 1, 2, 3, and 5. The subgroup of the virus was determined to be I by enzyme-linked immunosorbent assay. To characterize the serotype-specific glycoprotein of the virus at the molecular level, we cloned and sequenced the gene coding for VP7. Comparison of the deduced amino acid sequence with reported homologous sequences from human and animal rotavirus strains belonging to six different serotypes further supported the distinct immunological identity of the YM VP7 protein.

Amino Acid Sequence↗
PubMed1987

Synthesis in Escherichia coli and immunological characterization of a polypeptide containing the cleavage sites associated with trypsin enhancement of rotavirus SA11 infectivity.

About 45% of the rotavirus SA11 VP3 gene was inserted into a thermoinducible expression plasmid under the control of phage lambda PL promoter. The primary translation product predicted on the basis of the plasmid construction was a hybrid protein in which the 98 amino-terminal amino acids of phage MS2 polymerase were followed by amino acids 42 to 387 of the VP3 protein, which included the region containing the cleavage sites associated with trypsin enhancement of infectivity. On induction, a polypeptide that had the expected mol. wt. and contained VP3-related amino acid sequences as judged by immunological criteria, was synthesized to a level representing about 15% of the total bacterial protein. When a bacterial lysate enriched for the fusion polypeptide was injected into mice, it induced antibodies which inhibited haemagglutination and neutralized SA11 rotavirus infectivity.

Animals↗
PubMed1987

Prevalent patterns of serotype-specific seroconversion in Mexican children infected with rotavirus.

The level of neutralizing antibodies to rotaviruses belonging to serotypes 1, 3, and 4 was determined in acute- and convalescent-phase sera from 36 Mexican children with rotaviral diarrhea. Most of the infants who seroconverted fell into one of the following three patterns: single seroconversion to serotype 1; seroconversion to serotypes 1 and 4; or seroconversion to all three serotypes tested. The heterotypic neutralizing antibody responses to rotavirus infections are discussed.

Antibodies, Viral↗
PubMed1986

Conservation in rotaviruses of the protein region containing the two sites associated with trypsin enhancement of infectivity.

The primary structure of the region in the outer layer protein VP3, containing the two sites associated with trypsin enhancement of infectivity of rotavirus was found to be greatly conserved in cultivable human rotavirus serotypes 1 (Wa), 2 (DS1), and 3 (P) and in four human rotaviruses directly purified from feces. Significant differences with this conserved sequence were found in human rotavirus serotype 4 (ST3), isolated from an asymptomatic neonate, and in seven animal rotaviruses. However, the two trypsin cleavage sites were conserved in every rotavirus VP3 sequence analyzed.

Amino Acid Sequence↗
PubMed1986

Synthesis of the outer-capsid glycoprotein of the simian rotavirus SA11 in Escherichia coli.

The major outer layer protein, VP7, of the simian rotavirus SA11 has been synthesized in Escherichia coli, under the control of the lac promoter, as a fusion polypeptide with beta-galactosidase (beta Gal). The viral protein in the hybrid polypeptide is missing its N-terminal hydrophobic region and 26 amino acids (aa) at its C-terminus; it is flanked at both ends by beta Gal sequences. We have purified the hybrid 145-kDa protein by affinity chromatography using a column specific for beta Gal. Unexpectedly, a second protein of 118-kDa was also specifically bound to the column. N-terminal aa sequence analysis of these two proteins showed that the 145-kDa protein represented the expected fusion product, whereas the 118-kDa protein was apparently the result of initiation of translation at an internal site close to the 3' end of the viral sequence, in the chimeric mRNA. Each of the two polypeptides represented about 2 to 3% of the total protein of the recombinant-plasmid-carrying bacteria. When a bacterial lysate enriched for the hybrid polypeptides was injected into mice, it induced neutralizing antibodies to SA11 rotavirus.

Capsid↗
PubMed1986

Heterogeneity in base sequence among different DNA clones containing equivalent sequences of rotavirus double-stranded RNA.

The nucleotide sequences for several complementary DNA clones of the rotavirus genome were determined. When the sequences obtained from different clones for the same regions (16,000 bases) were compared, differences in eight base positions were observed. These discrepancies, approximately 1 in 2,000 bases, may be due to differences in individual RNA genomes resulting from multiple passages; infidelity of DNA synthesis in the cloning procedure; or both factors. Whatever the cause, this frequency of base substitution found in sequences of complementary DNA obtained from the same isolate should be considered when comparing DNA sequences obtained from independent isolates. On the other hand, the frequency of base changes observed suggests that the rotavirus genome is very conserved since the virus used for cDNA synthesis has been continuously passaged for 6 years without plaque purification.

Base Sequence↗
PubMed1985

Primary structure of the cleavage site associated with trypsin enhancement of rotavirus SA11 infectivity.

The primary structure of the trypsin cleavage site in the outer layer protein VP3 of rotavirus SA11 was determined. This cleavage enhances the infectivity of rotavirus SA11. Both VP8, one of the polypeptides generated by the cleavage, and VP3 had their alpha-NH2 blocked. Only VP5, the other polypeptide produced by the cleavage, was susceptible to sequential Edman degradation, indicating that it contained the new alpha-NH2 terminus generated by trypsin hydrolysis. The results indicated that purified VP5 is composed of two polypeptides with the following amino acid sequence at their N terminus: (a) ??VYTRAQPNQDAVVSKTS...; (b) AQPNQDAVVSKTS.... Sequencing of the DNA complementary to ds RNA segment 4 revealed a nucleotide sequence encoding the amino acid sequences indicated above, with only one different amino acid. From these results, the amino acid sequence of the site cleaved by trypsin was extended to cover the C termini (present in VP8). The following sequence, which contains two sites (indicated with asterisks) and can be cleaved by trypsin was deduced: ... VPVSIVSR*NIVYTR*AQPNQDIVVSKTS....

Amino Acid Sequence↗