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S L Payne

Publications and source records attributed to S L Payne.

29 records · Page 2Linked to original sources
PubMed1991

Purification and characterization of recombinant equine infectious anemia virus reverse transcriptase.

A 1.67-kb segment of the equine infectious anemia virus pol gene, encoding a 66-kDa reverse transcriptase (RT), was cloned and expressed in Escherichia coli. Recombinant RT, purified by a combination of metal chelate affinity chromatography and ion-exchange chromatography, displays both RNA-dependent DNA polymerase and RNase H activity. The affinity of purified RT for its replication primer, tRNA(3Lys) was equivalent to that observed for human immunodeficiency virus RT. Our data suggest that an additional domain between RT-RNase H and integrase on the equine infectious anemia virus pol open reading frame is not an integral component of the RT polypeptide.

Animals↗
PubMed1991

Characterization of the antigenic domains of the major core protein (p26) of equine infectious anemia virus.

A panel of recombinant trpLE-gag fusion proteins and synthetic peptides was used in Western immunoblot and enzyme-linked immunosorbent assays to identify segments of the major core protein (p26) of equine infectious anemia virus that are antigenic in horses during experimental and natural infections with the virus. The predominant humoral immune response was directed toward a highly immunogenic domain composed of 83 amino acids from the carboxy terminus of p26. The observed immunogenicity of p26 resembled that reported for p24 of human immunodeficiency virus type 1, suggesting the conservation of structural motifs in the lentiviral core proteins which are responsible for their observed immunogenicity during persistent lentivirus infections.

Animals↗
PubMed1989

Localization of conserved and variable antigenic domains of equine infectious anemia virus envelope glycoproteins using recombinant env-encoded protein fragments produced in Escherichia coli.

Previous characterizations of equine infectious anemia virus (EIAV) glycoprotein variation by DNA sequence analysis and epitope mapping using monoclonal antibodies (MAbs) have revealed the presence of conserved and variable regions within the EIAV env gene. To extend these studies, fragments of the EIAV envelope proteins gp90 and gp45 were expressed in Escherichia coli and used in Western blot analysis with a diverse panel of equine immune sera to identify antigenic segments. All sera from EIAV-infected animals reacted with the carboxyl terminal portion of gp90 and the amino terminal portion of gp45, indicating the highly conserved and immunodominant nature of these regions. Other gp90 segments, both from conserved and variable env sequences, displayed variable reactivities with the panel of equine sera. A panel of MAbs was also used in Western blot assays with the recombinant protein fragments for physical localization of previously identified MAb epitopes. The binding sites of two neutralizing MAbs were localized to a highly variable region of gp90, while nonneutralizing epitopes were localized to conserved and variable regions of the envelope glycoproteins. These results, in addition to localizing important antigenic sites on EIAV glycoproteins, indicate that previously defined conserved and variable env nucleotide sequences indeed encode protein sequences constituting conserved and variable immunogens during persistent infection by EIAV.

Animals↗
PubMed1988

EIAV genomic organization: further characterization by sequencing of purified glycoproteins and cDNA.

Nucleotide sequence analyses of two different proviral clones of equine infectious anemia virus (EIAV), designated lambda 12 (K. Rushlow et al., 1986, Virology 155, 309-321) and 1369 (T. Kawakami et al., 1987, Virology 158, 300-312), indicate significant differences in the organization of two critical regions of the viral genome, i.e., in the short open reading frames in the pol-env intergenic region and in the 5'-end of the env gene. To determine the correct structure of the EIAV genome, we have performed nucleotide sequence analyses of cDNA clones produced from viral RNA and direct sequencing of purified EIAV envelope glycoproteins (gp90 and gp45). The results of the cDNA sequencing confirm the presence of two short open reading frames in the pol-env intergenic region, as reported previously for the lambda 12 clone. The protein sequencing data correlated exactly with the amino-terminal sequences of gp90 and gp45 deduced from lambda 12 nucleotide sequences. However, the protein sequencing also revealed that the putative signal sequence of EIAV gp90 is not removed during processing. Thus, EIAV apparently contains short open reading frames analogous to human immunodeficiency virus, but differs in its mode of env polyprotein processing.

Amino Acid Sequence↗
PubMed1987

Antigenic variation and lentivirus persistence: variations in envelope gene sequences during EIAV infection resemble changes reported for sequential isolates of HIV.

The extent and nature of genomic variation among nine antigenically distinct EIAV isolates recovered during sequential clinical episodes from two experimentally infected ponies were examined by restriction fragment analysis and nucleotide sequencing. Only minor variations in restriction enzyme patterns were observed among the viral genomes. In contrast, env gene sequences of four isolates from one pony revealed numerous clustered base substitutions. Divergence in env gene nucleotide and deduced amino acid sequences between pairs of virus isolates ranged from 0.62 to 3.4% env gene mutation rates for isolates recovered during sequential febrile episodes were calculated to be greater than 10(-2) base substitutions per site per year. The degree and nature of env gene variation in EIAV is remarkably similar to the human immunodeficiency virus, suggesting common mechanisms for env gene variation among lentiviruses.

Amino Acid Sequence↗
PubMed1987

Course and extent of variation of equine infectious anemia virus during parallel persistent infections.

Comparisons of peptide and oligonucleotide maps of glycoproteins and RNA from nine isolates of equine infectious anemia virus (EIAV) that were generated during parallel infections of two Shetland ponies revealed that each isolate was structurally unique. Each EIAV isolate contained a unique subset of variant peptides, oligonucleotides, or both, indicating that structural variation in EIAV is a random and noncumulative process and that a large spectrum of possible EIAV variants can be generated in infected animals.

Animals↗
PubMed1986

Lentivirus genomic organization: the complete nucleotide sequence of the env gene region of equine infectious anemia virus.

The nucleotide sequence of the envelope (env) gene region of equine infectious anemia virus (EIAV), a member of the lentivirus subfamily of retroviruses, has been determined from a clone of integrated proviral DNA for which the gag and pol sequences have been reported previously. The env gene is 859 codons in length and the sequence reported here is consistent with the published biochemical properties of EIAV glycoproteins. The env gene region of EIAV shares considerable structural similarities but negligible sequence homologies with the env genes of other members of the lentivirus subfamily, visna virus, and human T-lymphotropic virus (HTLV-III) or lymphadenopathy virus (LAV). As in visna virus and HTLV-III, the polymerase (pol) and env genes of EIAV do not overlap. EIAV contains two short open reading frames (orf) of 50 and 66 codons in the pol-env intergenic region. However, unlike the orf Q regions reported for visna virus and HTLV-III, neither EIAV orf overlaps the 3' terminus of the adjacent pol gene. The EIAV genome also contains a third short open reading frame of 135 codons which is contained completely within the env gene, in contrast to the 3'-orf/orf F gene reported for HTLV-III/LAV which extends beyond the env gene terminus. These results provide a detailed description of the env gene region of EIAV and describe a number of characteristic features of genomic organization in lentiviruses which contrast with the genomic organization of oncogenic retroviruses.

Amino Acid Sequence↗
PubMed1986

Rapid emergence of novel antigenic and genetic variants of equine infectious anemia virus during persistent infection.

Previous results from our laboratory have demonstrated that equine infectious anemia virus displays structural variations in its surface glycoproteins and RNA genome during passage and chronic infections in experimentally infected Shetland ponies (Montelaro et al., J. Biol. Chem. 259:10539-10544, 1984; Payne et al., J. Gen. Virol. 65:1395-1399, 1984). The present study was undertaken to obtain an antigenic and biochemical characterization of equine infectious anemia virus isolates recovered from an experimentally infected pony during sequential disease episodes, each separated by intervals of only 4 to 8 weeks. The virus isolates could be distinguished antigenically by neutralization assays with serum from the infected pony and by Western blot analysis with a monoclonal antibody against the major surface glycoprotein gp90, thus demonstrating that novel antigenic variants of equine infectious anemia virus predominate during each clinical episode. The respective virion glycoproteins displayed different electrophoretic mobilities on sodium dodecyl sulfate-polyacrylamide gels, indicating structural variation. Tryptic peptide and glycopeptide maps of the viral proteins of each virus isolate revealed biochemical alterations involving amino acid sequence and glycosylation patterns in the virion surface glycoproteins gp90 and gp45. In contrast, no structural variation was observed in the internal viral proteins pp15, p26, and p9 from any of the four virus isolates. Oligonucleotide mapping experiments revealed similar but unique RNase T1-resistant oligonucleotide fingerprints of the RNA genomes of each of the virus isolates. Localization of altered oligonucleotides for one virus isolate placed two of three unique oligonucleotides within the predicted env gene region of the genome, perhaps correlating with the structural variation observed in the envelope glycoproteins. Thus these results support the concept that equine infectious anemia virus is indeed capable of relatively rapid genomic variations during replication, some of which result in altered glycoprotein structures and antigenic variants which are responsible for the unique periodic disease nature observed in persistently infected animals. The findings of envelope specific differences in isolates of visna virus and of human T-cell lymphotropic virus III (acquired immune deficiency syndrome-related virus) suggest that this variation may be a common characteristic of the subfamily Lentivirinae.

Animals↗
PubMed1980

Tactual speech perception by minimally trained deaf subjects.

Research on tactual perception of speech has shown that many phonetic contrasts can be transmitted to the deaf through artificial hearing devices that stimulate the sense of touch. Past research has emphasized long-term training with tactual reception for the achievement of maximal perceptual performance. The present study demonstrates that, with a brief training period, deaf adolescents can attain a high level of perceptual performance with a tactual speech system in discrimination of certain hard-to-lipread word pairs pronounced by both a male and female speaker. Thus some speech sounds previously indistinguishable by the deaf people can be immediately available for speech comprehension through the tactual vocoder; and other speech sounds will be recognized with further training. The reason that some contrasts are learned quickly and others require extensive training may be found in a pattern perception postulate proposed by Gavin (1979): word patterns that result in stimulation across a greater area of skin tend to be more discriminable than word patterns which stimulate only small areas of the skin.

Adolescent↗
PubMed1974

Heat injury and recovery of vegetative cells of Clostridium botulinum type E.

Vegetative cells of Clostridium botulinum type E (Tenno) were heated at 40.5 C in a prereduced peptone-yeast extract broth (PY). During the heating period, cell numbers remained essentially constant for 3 h as indicated by roll tube counts in PY agar (PYA); however, injury and recovery from injury were observed when the cells were enumerated using PYA containing either 0.06 or 0.07% bile salts.

Anaerobiosis↗