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At least 757 records · Page 42Linked to original sources
PubMed2005

Genetic characterization of H5N1 avian influenza viruses isolated in southern China during the 2003-04 avian influenza outbreaks.

The recent H5N1 avian influenza outbreaks in Asia spread over more than 8 countries. It has caused enormous economic loss and grand challenges for the public health. During these breakouts we isolated three strains of H5N1 Avian Influenza Virus (AIV) from chickens and one from duck in different farms of Southern China. We completely sequenced these four AIVs. Molecular characterization demonstrated that these strains retain the reported H5N1 AIV sequence properties relevant to virus virulence and host adaptation. Phylogeny results demonstrated that three of these isolates (except A/Chicken/Guangdong/174/04) were closely linked to other H5N1 AIVs isolated from the recent H5N1 outbreaks in Asia. Six of 8 segments (except PA and M) of A/Chicken/Guangdong/174/04 also shares a close linkage to other H5N1 AIVs isolated from the recent H5N1 outbreaks. However, the PA gene of A/Chicken/Guangdong/174/04 and another H5N1 strain forms a distinct subgroup along with an H6N1 AIV, and the M gene of A/Chicken/Guangdong/174/04 shows a close linkage to some H5N1 AIVs from aquatic species in China. Our findings suggest that a new genotype of AIV (in addition to previous reported ones) was present during the 2003-04 Asian bird flu outbreaks and that continuing virus surveillance of AIVs be conducted to monitor the evolutionary paths of the A/Chicken/Guangdong/174/04-like AIVs.

Animals↗
PubMed2000

Antigenic and genetic characterization of the fusion (F) protein of mumps virus strains.

Twelve strains of mumps virus, belonging to the A, C and D genotypes of the small hydrophobic (SH) protein gene, were investigated by nucleotide sequencing of the fusion protein gene. The nucleotide sequences and deduced amino acid sequences were aligned and compared with previously reported sequences of the gene. In addition an antigenic comparison between the F protein of different strains of the A, C and D genotypes was performed with ten monoclonal antibodies directed against the F protein of genotype A. Phylogenetic analysis of the coding region of the F gene showed the expected clustering of the different genotypes, as previously determined from the SH protein gene. Comparison of the 538 long amino acid sequence of the protein showed that only a small number of amino acids differed between the viral strains. The A genotype differed from B, C and D whereas the latter showed fewer consistent amino acid differences between themselves. Nine of the ten monoclonal antibodies reacted with the C and D genotypes and one failed to react with these genotypes. It is concluded that the structure and antigenicity of the F protein is well conserved both intra- and intergenotypically over long periods of time.

Amino Acid Sequence↗
PubMed2006

Genetic characterization of a new mammalian reovirus, type 2 Winnipeg (T2W).

We previously described isolation of a potentially new reovirus strain from the central nervous system of an 8-week-old female infant with a history of active varicella, oral thrush, hypoalbuminemia, intermittent fevers, diarrhea and feeding intolerance [Hermann et al., Ped. Inf. Dis J. 23, 373 (2004)]. This reovirus strain was tentatively identified as a member of the serotype 2 group by virus neutralization and RNA-gel electrophoresis studies and has been named type 2 Winnipeg (T2W). For this study we determined the nucleotide sequences of the T2W S1, S2, S3 and S4 genome segments to allow molecular comparison with other reoviruses. Comparative segment alignments of T2W S1 gene sequence with other reovirus S1 sequences showed T2W belongs to reovirus serotype 2. T2W S1 is most similar to the S1 genes of reovirus strains T2/Human/Netherlands/1,984 and T2/Human/Netherlands/1,973 with nucleotide identity >93%. The T2W S2 gene showed highest identity to reovirus T1 Lang S2 (approximately 75%). The T2W S3 gene showed highest identity to the S3 gene of T3/Human/Netherlands/1,983 (approximately 74%), and the T2W S4 gene showed highest identity to the T2 Jones S4 gene (approximately 73%). Pairwise protein comparisons between T2W sigma proteins and all available reovirus sigma proteins ranged from <21% identity for the sigma1 comparisons to more than 95% identity for sigma2 comparisons. The predicted T2W sigma1, sigma2 and sigma3 protein sequences were confirmed by mass spectrometry.

Amino Acid Sequence↗
PubMed2002

Serological and genetic characterization of newly isolated Peaton virus in Japan. Brief report.

The viruses were isolated from the blood of sentinel cattle and Culicoides biting midges in the Kyushu district, southwestern Japan, in 1999 and identified by neutralization tests as Peaton (PEA) viruses. Before this study, PEA virus had been isolated in Australia only. The nucleotide identity of the nucleocapsid (N) protein encoded by the S segment ranged from 91.1 to 91.6% between the Australian and Japanese strains. A phylogenetic analysis of the N protein sequence revealed that the PEA virus strains are closely related to Aino (AIN) virus and suggested reassortment events for PEA and AIN viruses.

Amino Acid Sequence↗
PubMed1988

Comparative biochemical and genetic characterization of clonally related human B-cell lines secreting pathogenic anti-Pr2 cold agglutinins.

To study the biology of cold autoimmune hemolytic anemia, Epstein-Barr virus (EBV)-transformed B-cell clones were established from a patient with splenic lymphoma associated with immune hemolysis due to an anti-Pr2 cold autoantibody. Studies were performed comparing the cold autoantibody present in culture supernatants of these cell lines to the pathogenic cold autoantibodies present in the patient's plasma. Cytogenetic studies of splenic lymphocytes demonstrated an abnormal karyotype (51XX, +3, +9, +12, +13, +18). After EBV transformation, eight clones secreting IgM, kappa anti-Pr were isolated; each clone had the same abnormal karyotype as above. DNA isolated from the clones and spleen was analyzed by Southern blot hybridization with JH, C mu, and C kappa probes; identical gene rearrangements were seen in each case. Anti-Pr antibodies, isolated from culture supernatant and serum were compared by isoelectric focusing (IEF) and demonstrated similar banding patterns. Distinctive binding patterns, however, were observed in 2/8 clones, suggesting structural differences. Adsorption studies with red blood cells further showed that the observed IEF banding patterns were solely due to anti-Pr cold autoantibody. With a thin-layer chromatography method, the biochemical determinants recognized by the cold autoantibodies were defined as glycolipids containing Neu Ac alpha 2-3Gal beta 1-4Glc sequences. The data demonstrate that the autoantibodies of the EBV-transformed B-cell lines were similar to the pathogenic monoclonal serum autoantibody in both structure and specificity. These clonal cell lines may thus serve to further study the biology of human B-cell lymphomas with defined autoantibody specificity.

Adult↗
PubMed1987

Genetic characterization of an Escherichia coli mutant deficient in organophosphonate biodegradation.

An E. coli mutant deficient in organophosphonate biodegradation has been complemented with a cosmid library prepared from a BamHI partial digest of wild-type E. coli W3110. Mutant E. coli SL724, when transformed with cosmid pSL163 and plasmid pSL263, regained the ability to exploit ethylphosphonate as a sole source of phosphorus during growth. In route to complementation, the Tn5 insert of SL724 was subcloned and restriction enzyme mapped. Complementing pSL163 and pSL263 were also characterized via restriction enzyme digests.

Cosmids↗
PubMed1991

Isolation and genetic characterization of a renal epithelial cell mutant defective in vasopressin (V2) receptor binding and function.

A novel mutant of the LLC-PK1 renal epithelial cell line, VPR1, was isolated after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine and selection using a photoactivatable vasopressin analogue [1-(3-mercapto)propionic acid, 8-(N6-4-azidophenylamidino)lysine] vasopressin. The VPR1 mutant cell line possessed less than 5% parental V2 receptor binding for vasopressin but exhibited normal calcitonin receptor binding. In contrast to LLC-PK1 cells (wild type), VPR1 cells exhibited no response to vasopressin in terms of in vitro adenylate cyclase activation, in vivo cAMP production, or urokinase-type plasminogen activator induction. The responses of VPR1 cells to other agents, such as calcitonin, the adenylate cyclase activator forskolin, the GTP analogue guanosine 5'-[beta, gamma-imino] triphosphate, 8-bromo adenosine-3',5'-monophosphate were comparable to those of the parental cell line. Somatic cell hybrids were derived from the cell lines LLC-PK1 and VPR1 and analyzed for the dominance/recessiveness of the VPR1 mutant phenotype. Hybrids were found to possess normal vasopressin binding activity as well as functional responses to the hormone, indicating that the mutation affecting the V2 receptor in VPR1 cells is recessive. The VPR1 cell line may thus have application as a recipient for the expression of the V2 receptor gene using DNA-transfer.

Adenylyl Cyclases↗
PubMed1989

Antigenic and genetic characterization of three influenza C strains isolated in the Kinki district of Japan in 1982-1983.

Three strains of influenza C virus (C/Kyoto/41/82, C/Nara/82, C/Hyogo/1/83) have been isolated from humans in the Kinki district of Japan between February 1982 and December 1983. Oligonucleotide mapping of total vRNA and antigenic analysis with anti-HE monoclonal antibodies have shown previously that they are closely similar to one another but dissimilar to any of the strains isolated in Japan before 1982. In the present study, the nucleotide sequences of the hemagglutinin-esterase (HE) genes of these three strains were determined and compared with those of the previously published strains. The results revealed that the Kinki isolates had a high nucleotide sequence homology (98.4-98.5%) with the virus isolated in 1980 in the United States (C/Mississippi/1/80). Similarity of the Kinki strains to C/Mississippi/1/80 was also confirmed by oligonucleotide mapping of total vRNA and antigenic comparison using a panel of 11 anti-HE monoclonal antibodies. The isolates from Kinki and Mississippi could be distinguished from the previously isolated strains in serological tests with heterogeneous sera, suggesting that they may have possessed epidemiological advantage in Japan around 1982-1983. These observations raise the possibility that the rapid spread of influenza C variant closely related to C/Mississippi/1/80 has occurred in Kinki in 1982-1983 presumably because this imported virus was largely different in antigenicity from the previously prevalent ones.

Antibodies, Monoclonal↗
PubMed1987

Genetic characterization of JC virus Tokyo-1 strain, a variant oncogenic in rodents.

The genome DNA of JC virus Tokyo-1 strain [JCV(Tokyo-1)], a variant oncogenic in rodents, was molecularly cloned directly from the brain of a Japanese patient with progressive multifocal leukoencephalopathy and from tissue culture, and the restriction enzyme cleavage pattern and regulatory sequences were determined. The restriction pattern of the cloned JCV(Tokyo-1) DNA was different from those of JCVs previously reported in the United States and Germany. Also, the arrangement of the regulatory sequence was unique to this strain. Thus JCV(Tokyo-1) can be classified as a new subtype. The relationship between the restriction pattern and the regulatory sequence of JCV(Tokyo-1), and its characteristic oncogenicity, is discussed.

Animals↗
PubMed1995

Genetic characterization of a human isolate of Puumala hantavirus from France.

PUU90-13 is a strain of Puumala (PUU) virus (family Bunyaviridae: genus Hantavirus) isolated from a human in northeastern France (Rollin et al., 1995). This report describes the full-length sequences of the small (S) and medium (M) genomic RNAs of PUU90-13. The terminal sequences of both the S and M genomic RNAs were found to be conserved and imperfectly complementary. The S RNA of PUU90-13 is 1847 nt in length and contains the nucleocapsid (N) protein gene and a potential overlapping open reading frame (ORF-2) previously described in other hantaviruses. Statistical analysis of the third base substitution frequency in the N ORFs of PUU90-13 and other PUU viruses suggests that the ORF-2 is functional. The M RNA is 3681 nt in length and encodes the glycoprotein precursor. Both genomic segments share the highest degree of nucleotide and amino acid sequence identity with PUUBerkel, a PUU virus from Germany. Phylogenetic analyses of sequences from both segments indicate that PUU90-13 occupies a distinct Western European PUU virus lineage that it shares with PUUBerkel. Both PUU90-13 and PUUBerkel lack a potential N-linked glycosylation site found on the G2 glycoprotein of other PUU viruses.

Amino Acid Sequence↗
PubMed1996

The first isolation, in vitro propagation, and genetic characterization of Ehrlichia canis in Israel.

Ehrlichia canis, the etiologic agent of canine ehrlichiosis, was isolated in Israel from a naturally infected dog with acute signs of the disease. The organism designated E. canis 611, was passaged experimentally to a beagle, from which it was propagated in primary canine monocytes. The organism was then grown in vitro in a continuous canine cell line, DH82. Nine beagles subsequently injected with whole E. canis-infected blood all developed typical symptoms of ehrlichiosis. An indirect immunofluorescence antibody test to E. canis was developed and compared with a commercial kit, revealing a good correlation between the two assays. Transmission electron microscopy of DH82 cells infected with the Israeli strain of E. canis (611), revealed organisms similar to those described in the literature: two different forms of morulae appeared, one tightly, the other loosely, packed. The 16S rRNA gene sequence obtained from the Israeli Ehrlichia isolate was compared with other isolates, E. canis Oklahoma and E. canis Florida. The Israeli strain 16S rRNA had three nucleotide differences from the Oklahoma isolate, and four nucleotide differences from the Florida isolate, in addition to one nucleotide gap in each. The Israeli isolate was found to be 0.54% different from the Oklahoma strain, and 0.61% different from the Florida strain. There are the same magnitudes of differences displayed by the other most closely related group in the phylogenetic tree, namely Ehrlichia equi, Ehrlichia phagocytophilia and the human granulocytic ehrlichia.

Animals↗
PubMed1985

Physical and genetic characterization of cloned enterobactin genomic sequences from Escherichia coli K-12.

We have cloned genes responsible for enterobactin synthesis (entD) and transport (fepA,fes) from Escherichia coli K-12. Relevant recombinant plasmids enabled EntD- and transport-defective mutants to grow on iron-limiting medium. Subcloning and deletion analysis demonstrated that the gene order is entD-fepA-fes. Protein synthesis studies in minicells suggest that FepA is first translated as an Mr 84 000 precursor, which is subsequently cleaved to the active Mr 81 000 receptor; the fes gene product is an Mr 44 000 protein; no polypeptide has been identified as the entD gene product.

Bacterial Outer Membrane Proteins↗