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  • 11
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary.  Rotavirus clones A5–10 and A5–16 isolated from a bovine rotavirus strain A5 possess NSP1 gene which has a point mutation generating a nonsense codon and a 500 base-deletion, respectively. As a result, the two A5 clones encode truncated NSP1 product which lacks cysteine-rich region forming zinc finger motif. In order to analyze reassortment of these mutated NSP1 gene with RNA segments from heterologous strains, we investigated a number of reassortant clones derived from coinfection with either A5–10, A5–16 or a reference strain A5–13 (possessing intact NSP1 gene) and either simian rotavirus SA11 or human rotavirus KU. In coinfection with SA11 and A5–13, selection rates of A5–13 segments in reassortants ranged approximately from 20 to 70% (46% for NSP1 gene). In contrast, in the reassortment between SA11 and A5–10 or between SA11 and A5–16, selection rates of NSP1 gene from A5–10 and A5–16 were only 1% (one clone) and 0%, respectively. In reassortants from crosses KU × A5-clones, selection rate of A5–13 NSP1 gene decreased to 15%, while 11 reassortants with A5–10 NSP1 gene (31%) and one reassortant with A5–16 NSP1 gene (2%) were isolated. Reassortants with A5–10 NSP1 possessed a single gene (segment 9 or 11) from KU in the genetic background of A5–10. One reassortant clone (cl-55) with A5–16 NSP1 gene possessed KU gene segments 3, 4, and 8–11. When single-step growth curves were compared, the reassortant cl-55 showed almost identical growth curve to that of KU, while KU showed a better replication than A5–16. These results indicated that although A5–10 or A5–16 NSP1 gene encoding the truncated NSP1 is selected into reassortants much less efficiently than normal NSP1 gene, the reassortants with the mutated NSP1 gene and RNA segments from heterologous strains normally replicated in cultured cells. Thus, cysteine-rich region of NSP1 was not considered essential for genome segment reassortment with heterologous virus.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two neutralizing monoclonal antibodies (4 C 4 and 4 F 2) against type 1 poliovirus, Mahoney strain, recognized distinct antigenic sites of the virus particles; 4 C 4 antibody bound to vertices of native and heated (56° C, 30 minutes) virus of Mahoney strain, while 4 F 2 antibody reacted with specific surface protrusions of native virus of Mahoney and Sabin strains. The difference in the location of neutralization epitopes with which the two antibodies react was confirmed in the neutralization reaction by the use of mutants resistant to 4 C 4 and 4 F 2 antibody. In immune electron microscopy, double immunodiffusion and sucrose density gradient analysis of virus-antibody complexes, the two antibodies showed a marked difference in their virus-precipitating activities. The 4 C 4 antibody recognizing vertices of the virus particle had little virus-precipitating activity. In contrast, the 4 F 2 antibody that bound to specific surface protrusions of native virus aggregated virus particle efficiently. In neutralization assays, however, the 4 C 4 antibody exhibited a slightly stronger neutralizing activity than the 4 F 2 antibody. Thus, it was suggested that the strength in precipitating activities of the two antibodies did not correlate with that in their neutralizing activities.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three different serotypes of human rotavirus isolates defined in our laboratory were compared by cross neutralization tests with human rotavirus serotypes established in the NIH, U.S.A. The results clearly demonstrated that our three serotypes correspond well to their serotypes Wa, DS-1 and M (or P). Using the three serotype-specific rabbit antisera, all of the 16 strains isolated to date could be assigned to one of those three serotypes. The prevalence of human rotavirus serotypes 1, 2 and 3 among inhabitants of Sapporo and its outskirts was investigated based on the results of neutralizing antibody distribution patterns by age using sera of non-infectious disease patients examined at the Sapporo Medical College Hospital. Neutralizing antibody titers were measured against four strains, KU and K8 (serotype 1), S2 (serotype 2) and YO (serotype 3). The results revealed that serum antibody titers against KU, K8 and YO strains rose with time after birth, reaching the highest antibody distribution levels in either the 3–5-year-old or 6–9-year-old age group, while antibody against S2 strain tended to be lower than that against the other three strains throughout all age ranges examined, with the highest level being shown in the adult group.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Archives of virology 139 (1994), S. 209-215 
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Antigenic and genomic properties of equine rotavirus strain CH3 isolated in Japan were studied by cross-neutralization tests and nucleotide sequence determination of the VP4 and VP7 genes. It was shown that the strain CH3 belongs to G14 and shares VP4 genotype with strain H2.
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  • 15
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We previously found the preferential selection of VP7 gene from a parent rotavirus strain SA11 with G serotype 3 (G3) in the sequential passages after mixed infection of simian rotavirus SA11 and SA11-human rotavirus single-VP7 gene-substitution reassortants with G1, G2, or G4 specificity. However, it has not been known whether or not VP7 genes derived from other strains with G3 specificity (G3-VP7 gene) are preferentially selected in the genetic background of SA11. To address this question, mixed infections followed by multiple passages were performed with a reassortant SA11-L2/KU-R1 (SKR1) (which possesses VP7 gene derived from G1 human rotavirus KU and other 10 genes of SA11 origin) and one of the five G3-rotaviruses, RRV, K9, YO, AK35, and S3. After the 10th passage, selection rates of SA11-L2/KU-R1 gene 9 (G1-VP7 gene) and gene 5 (NSP1 gene) reduced considerably (0 to 20.4%) in the clones obtained from all the coinfection experiments, while all or some of other segments were preferentially selected from SKR1 depending on the pairs of coinfection. When viral growth kinetics was examined, SKR1 exhibited better growth and reached a higher titer than any G3 viruses. Although the generated reassortants with VP7 gene and NSP1 gene derived from G3 viruses showed almost similar growth kinetics to that of SKR1 during the first 20 h of replication, the titers of these reassortants were higher than that of SKR1 after 36h postinfection. The results obtained in this study suggested that G3-VP7 gene is functionally more adapted to the genetic background of SA11.
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  • 16
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to study the effect of selection pressure of anti-VP4 and anti-VP7 neutralizing monoclonal antibodies(N-MAbs) on reassortant formation, 424 reassortant clones were produced from mixed cultures of human rotavirus strains Wa and HN126 and their genotypes were analysed. Reassortant selection was done with four types of N-MAb: anti-VP4 MAb to Wa and anti-VP7 MAb to HN126(selection A); anti-VP4 MAb to HN126 and anti-VP7 MAb to Wa(selection B); anti-VP7 MAb to Wa(selection C); and anti-VP4 MAb to Wa(selection D). In each selection experiment, more than 100 clones were isolated, and the parental origin of RNA segments was identified by polyacrylamide gel electrophoresis. All clones isolated by selections A and B were found to be antigenic mosaic reassortants with the VP4 gene of HN126 and the VP7 gene of Wa and antigenic mosaic reassortants with the VP4 gene of Wa and the VP7 gene of HN126, respectively. Although in reassortants of both selections, RNA segments 2, 3, 5 and 6 were selected from strain Wa at considerably high rates, selection rates of RNA segments 1, 7, 8, and 11 were significantly different between selection A and B. In reassortants from selection C and D, selection rates of RNA segments 1, 3, 6, 7, 8, and 11 from Wa were significantly lower than those in selection A and B, whereas RNA segments 2 and 5 were almost exclusively selected from Wa as observed in selection A and B. These results indicated the presence of two types of nonrandom gene selection in reassortant formation, one strongly dependent on, and another irrespective of, the selection pressure with N-MAbs.
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  • 17
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied the competitive growth among SA11-L2(G3) and its single-human VP7 gene-substitution reassortants SA11-L2/KU-R1(G1) and SA11-L2/DS1-R1(G2), which have the genetic background of SA11-L2, during sequential passages after mixed infection. When the same infectious units (m.o.i. of 5 p.f.u./cell) of SA11-L2 and a reassortant SA11-L2/KU-R1 were inoculated onto and passaged in MA104 cells, 88% of the virus clones isolated from the culture fluid at the 3rd passage belonged to G3, and all the clones from the 10th passage had G3 specificity. Even when SA11-L2/KU-R1 with titer 10 times higher than that of SA11-L2 was used in the coinfection, the predominance of clones with G3-VP7 was observed. Although G2 clones slightly surpassed G1 clones in number in the mixed culture of SA11-L2/KU-R1 and SA11-L2/DS1-R1, G3 clones predominated in the virus progeny from a mixed culture infected with the same titers of SA11-L2, SA11-L2/KU-R1, and SA11-L2/DS1-R1. However, no significant difference in viral growth was detected among SA11-L2 and the two reassortants.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Archives of virology 33 (1971), S. 113-125 
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Poliovirus inhibitors present in normal equine and bovine sera were studied by means of radioimmunoelectrophoresis and column chromatography. The inhibitors in individual equine sera were identified as either one of the three immunoglobulins, γM, γA(T) and γG, or mixtures of them, while those in bovine sera were found to be either one of γM and γG globulins, or the mixture of the two. The inhibitors belonging to different classes of immunoglobulin differed in their mode of action against the virus. γM inhibitors were characterized by distinct activities in the kinetic neutralization and the plaque reduction tests. In contrast, γA(T) inhibitors were highly active in the plaque-reduction and the precipitation-in-agar-gel tests, although they were inactive in the kinetics of neutralization. There were two types of γG inhibitors. One did not neutralize the virus in the kinetic test, despite its distinct virus-precipitating activity. The other could neutralize but not precipitate the virusin vitro. Avidity of the inhibitors as revealed by dissociation of virus-inhibitor complexes at acidic pH's also differed among the immunoglobulin classes of the inhibitors. The complex formed with the NaIO4-treated γA(T) inhibitor was most stable and was not dissociated even at pH as low as 2.0.
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  • 19
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A non-neutralizing monoclonal antibody (YO-60) against human rotavirus was found to be directed to VP2 (90,000-dalton protein), one of the two major components of the inner capsid. The reactivity patterns of the YO-60 antibody were very similar, though not identical, to those of subgroup II-specific YO-5 monoclonal antibody directed to VP6 (42,000-dalton protein), the other major component of the inner capsid. These results indicated the possible presence of a subgroup-specific antigen on VP2 in addition to the one on VP6.
    Type of Medium: Electronic Resource
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  • 20
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During an epidemiological study of human rotavirus in Metro Manila, Philippines, we found 20 unusual strains which belong to subgroup I but have “long” RNA pattern typical of subgroup II human rotavirus. The RNA patterns of the 20 strains were classified into four groups though they were very similar to each other. Four strains, designated L4, L26, L27, and L34 were isolated in MA 104 cells from stool specimens. They possessed subgroup I specificity and long RNA pattern identical to that of the viruses in the original stool samples. The serotype specificity of these strains could not be determined by either enzyme-linked immunosorbent assay (ELISA) or neutralization test, while one strain (L27) was neutralized by serotype 2-specific anti-VP4 monoclonal antibody. These strains were suggested to have an unusual antigenicity on VP7.
    Type of Medium: Electronic Resource
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