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P H Berger

Publications and source records attributed to P H Berger.

At least 19 recordsLinked to original sources
PubMed2006

Whole genome characterization of Potato virus Y isolates collected in the western USA and their comparison to isolates from Europe and Canada.

Potato virus Y (PVY) is a serious potato pathogen that affects potato seed and commercial production crops. In recent decades, novel PVY strains have been described that cause necrotic symptoms on tobacco foliage and/or potato tubers. The major PVY strains that affect potato include PVY(O) and PVY(N), which have distinct serotypes that can be differentiated by immunoassay. Other economically important strain variants are derived from recombination events, including variants that cause tuber necrotic symptoms (PVY(NTN)) and PVY(O) serotypes that cause tobacco veinal necrosis (PVY(N)-W, PVY(N:O)). Although the PVY(NTN) and PVY(N)-W variants were first reported in Europe, apparently similar strains have been appearing in North America. Confirmation of the existence of these recombinant strains in North America is important, as is whether they spread from a common source or were derived by independent recombination. Whole genome sequencing can be used to positively identify strain variants and begin to address the issue of origins. Symptomology, serology, RT-PCR, and partial sequencing of the coat protein region were used to identify isolates of the PVY(NTN), PVY(N), PVY(NA-N), and PVY(N:O) for whole-genome sequencing. Sequencing confirmed the presence of PVY(NTN) and PVY(N) isolates that were >99% identical to European sequences deposited in GenBank in the 1990's. Sequences of the PVY(NA-N) and PVY(N:O) types were 99.0% and 99.5% identical to known sequences, respectively. There was no indication that recombinant strains PVY(NTN) or PVY(N:O) had different parental origins than recombinant strains previously sequenced. This is the first confirmation by whole-genome sequencing that "European"-type strain variants of PVY(N) and PVY(NTN) are present in North America, and the first reported full-length sequence of a tuber necrotic isolate of PVY(N:O).

Canada↗
PubMed2005

Wheat streak mosaic virus--structural parameters for a Potyvirus.

Wheat streak mosaic virus is a Tritimovirus, a member of the Potyviridae family, which includes the very large Potyvirus genus. We have examined wheat streak mosaic virus by electron microscopy and fiber diffraction from partially oriented sols, and analyzed the results to estimate the symmetry and structural parameters of the viral helix. The virions have an apparent radius of 63 +/- 5 A. The viral helix has a pitch of 33.4 A +/- 0.6 A. There appear to be 6.9 subunits per turn of the helix, although we cannot completely eliminate values of 5.9 or 7.9 for this parameter.

Capsid Proteins↗
PubMed2004

Life history of the bird cherry-oat aphid, Rhopalosiphum padi (Homoptera: Aphididae), on transgenic and untransformed wheat challenged with barley yellow dwarf virus.

The life history of Rhopalosiphum padi (L.) was monitored on transgenic and untransformed (soft white winter wheat plants that were infected with Barley yellow dwarf virus (BLDV), noninfected, or challenged with virus-free aphids under laboratory conditions. Two transgenic soft white winter wheat genotypes (103.1J and 126.02) derived from the parental variety Lambert and expressing the barley yellow dwarf virus coat protein gene, and two untransformed varieties, virus-susceptible Lambert and virus-tolerant Caldwell, were tested. B. padi nymphal development was significantly longer on the transgenic genotypes infected with BYDV, compared with noninfected transgenic plants. In contrast, nymphal development on Lambert was significantly shorter on BYDV-infected than on noninfected plants. Nymphal development on noninfected Lambert was significantly longer than on noninfected transgenics. No significant difference in nymphal development period was detected between virus-infected and noninfected Caldwell. Aphid total fecundity, length of reproductive period, and intrinsic rate of increase were significantly reduced on BYDV-infected transgenic plants compared with BYDV-infected Lambert. In contrast, reproductive period, total adult fecundity, and intrinsic rate of increase on noninfected Lambert were significantly reduced compared with noninfected transgenics. Transgenic plants infected with BYDV were inferior hosts for R. padi compared with infected Lambert. However, noninfected transgenics were superior hosts for aphids than noninfected Lambert. Moderate resistance to BYDV, as indicated by a significantly lower virus titer, was detected in the transgenic genotypes compared with the untransformed ones. Results show for the first time that transgenic virus resistance in wheat can indirectly influence R. padi life history.

Animals↗
PubMed2002

Digoxin poisoning and anuric acute renal failure: efficiency of the treatment associating digoxin-specific antibodies (Fab) and plasma exchanges.

Digoxin-specific antibodies (Fab) are currently the treatment of choice for digoxin intoxication. These fragments bind to digoxin, leading to Fab-digoxin complexes, and promote the release of receptor-bound digoxin. These complexes are renally excreted. In the case of anuria, they could be dissociated and lead to renewed intoxication. In this case plasma exchanges are proposed. We report the case of an anuric patient with digoxin intoxication, treated with a Fab injection, followed by a plasma exchange 16 hours later, a second Fab injection was given followed by two plasma exchanges, 38 and 86 hours later. The disappearance of cardiac abnormalities showed the efficiency of the Fab, the drop in serum digoxin concentration and the high digoxin concentration in the exchanged plasma indicate effective elimination. The association of Fab and plasma exchanges could be proposed in the case of digoxin intoxication in the anuric patient.

Acute Kidney Injury↗
PubMed2001

14 years of therapeutic plasma exchange in France.

The French Registry for plasma exchange (PE) was set up in 1985. For 14 years it has allowed analysis of the techniques used along with the indications and complications. Recent analysis shows a slight fall in activity as some studies have ended, while the neurological disorders remain the most frequent indications for PE. The important changes observed over the years are the increased use of the centrifugation technique, the development of plasma and whole blood treatment and plasma substitution using a mixture of albumin and pentastarch. The French Registry for PE is the largest such database which, along with the Canadian Registry for therapeutic hemapheresis, allows both retrospective and prospective studies.

Anticoagulants↗
PubMed2000

The complete nucleotide sequence of apple mosaic virus (ApMV) RNA 1 and RNA 2: ApMV is more closely related to alfalfa mosaic virus than to other ilarviruses.

The complete nucleotide sequences of apple mosaic virus RNA 1 and 2 have been characterized. Apple mosaic virus RNA 1 is 3476 nucleotides in length and encodes a single large open reading frame (ORF), whereas apple mosaic virus RNA 2 is 2979 nucleotides in length and also encodes a single ORF. The amino acid sequences encoded by RNA 1 and 2 show similarity to all of the other ilarviruses for which sequence data are available, but both are more closely related to alfalfa mosaic virus (AMV) than to other ilarviruses. Points of similarity include the absence of ORF 2b, present on the RNA 2 of all previously characterized ilarviruses. The close relationship to AMV also occurs in the movement protein, encoded by RNA 3, but not with the coat protein. These data suggest that the present taxonomy should be revised, and that AMV should be considered an aphid-transmissible ilarvirus.

5' Untranslated Regions↗
PubMed1999

Three epitopes located on the coat protein amino terminus of viruses in the bean common mosaic potyvirus subgroup.

Twenty-seven of 29 strains of viruses in the bean common mosaic virus (BCMV) subgroup of legume-infecting potyviruses reacted strongly with one or more of the monoclonal antibodies (MAbs) which are known to be specific for epitopes located along the 50 amino acids which constitute the N-terminal end of the viral coat protein. Approximately one half of the virus strains reacted with the N-terminal epitope specific (NTES) MAb 4G12 which is specific for epitope E/B4, while the other half reacted with NTES MAbs 4A1 or 4F9 which are specific for epitope E/B3. All but two strains contained at least one of these epitopes while no strain contained both. Competitive assays using five sequential, non-overlapping, synthetic, 10mer peptides indicated that the amino acids critical for epitope E/B3 reaction were located at positions 5, 7, and 10 from the N-terminal end of the coat protein. By deduction we postulate that the amino acids critical for epitope E/B4 are located at positions 10, 16, and 17. Because epitope E/B3 requires isoleucine at position 10 for expression whereas epitope E/B4 requires valine to be expressed, no one strain can express both epitopes. Two viruses in our tests (azuki mosaic and Dendrobium mosaic viruses) had deletions in this portion of their sequence explaining their failure to react MAbs specific for either epitope. The critical amino acids for a third epitope, E/B3A, were located at positions 16 and 17. We found no correlation between any of the three N-terminal epitopes defined in this study and the presence or absence of any biological property that we could accurately measure: i.e., symptomatology, host range, or pathotype. However, when coat protein sequences were aligned according to epitope type E/B3 or E/B4, we found that sequences within groups had high levels of identity while between group identities were low. We also found that sequences in the 3'-end non-coding region exhibited similar relationships within and between epitope groups. Two strains of BCMV (NL-4 and RU-1) were found to possess coat protein sequences typical of epitope E/B4 but 3'-NCR sequences typical of epitope E/B3. These data suggest that both strains may be the result of natural recombinants between the two epitope groups.

Amino Acid Sequence↗
PubMed1998

Nucleotide sequence of both genomic RNAs of a North American tobacco rattle virus isolate.

The complete sequence of a North American tobacco rattle virus (TRV) isolate, 'Oregon yellow' (ORY), was determined from cDNA and RT-PCR clones derived from the two genomic RNAs of this isolate. The RNA-1 is 6790 bases and RNA-2 is 3261 bases. The sequence of TRV-ORY RNA-1 was similar to RNA-1 to TRV isolate SYM, and differs in 48 nucleotides. TRV-ORY RNA-1 was one base shorter than--SYM, and had 47 base substitutions resulting in 12 amino acid substitutions of which 4 were conservative. The RNA-2 of TRV-ORY was distinct from RNA-2 of other characterized TRV isolates and contained three open reading frames (ORFs) that could potentially code for proteins of MW 22.4 kDa, 37.6 kDa and 17.9 kDa. Based on the homology of the predicted amino acid sequence with those of other tobraviruses. ORF1 of RNA-2 encodes the coat protein (CP). The protein sequence of ORF2 had regions of limited similarity with those of ORF2 of two other TRV isolates and pea early browning tobravirus. The ORF3 was unique to TRV-ORY. Phylogenetic analysis of tobravirus CPs indicated that TRV-ORY was most closely related to pepper ringspot tobravirus and TRV-TCM. The relationship of tobravirus CPs to other rod-shaped tubular plant viruses is also discussed.

Base Sequence↗
PubMed1998

Coat protein-mediated resistance to pea enation mosaic virus in transgenic Pisum sativum L.

Pea (Pisum sativum L.) plants were transformed in planta by injection/electroporation of axillary meristems with a chimeric pea enation mosaic virus (PEMV) coat protein gene contruct. R1 progenies of these plants were shown to harbor the transgene by polymerase chain reaction (PCR) and genomic Southern analysis, while transgene expression was demonstrated by western blot analysis. Transgenic R2, R3 and R4 plants displayed delayed or transient PEMV multiplication and attenuated symptoms as compared to control inoculated individuals.

Base Sequence↗
PubMed1997

Phylogenetic analysis of the Potyviridae with emphasis on legume-infecting potyviruses.

The 3'-terminal nucleotide sequences of thirteen authenticated strains of bean common mosaic virus (BCMV) and one strain of bean common mosaic necrosis virus (BCMNV) were obtained. The regions sequenced included the coat protein coding sequence and 3'-end non-coding region. These data, combined with sequence information from other legume-infecting potyviruses and the Potyviridae were used for phylogenetic analysis. Evidence is provided for delineation of BCMNV as distinct from BCMV and the inclusion of azuki mosaic, dendrobium mosaic, blackeye cowpea mosaic, and peanut stripe viruses as strains of BCMV. This relationship defines the members of the BCMV and BCMNV subgroups. These data also provide a basis upon which to define virus strains, in combination with biological data. Other aspects and implications of legume-infecting potyvirus phylogenetics are discussed.

Amino Acid Sequence↗
PubMed1997

Characterization of the canine type C enterotoxin produced by Staphylococcus intermedius pyoderma isolates.

The type C staphylococcal enterotoxins (SECs) are a group of highly conserved proteins with substantial antigenic cross-reactivity. Although Staphylococcus intermedius and coagulase-positive species of staphylococci are reported to produce SEC and other SEs, toxins produced by species other than Staphylococcus aureus have not been previously characterized. In this study we report the molecular, biological, and immunological properties of the canine SEC (SECcanine) expressed by pathogenic isolates of S. intermedius. The mature form of SECcanine has 239 amino acid residues and a pI of 7.0. Typical of the SEs, purified SECcanine induces an emetic response in monkeys and the proliferation of T cells in a Vbeta-dependent manner. Although SECcanine has >95% sequence identity to previously described SEC variants, its sequence is most related to SEC2 and SEC3. In contrast to the sequence similarity, the Vbeta profile induced by SECcanine is typical of that induced by SEC1. This result is likely explained by the conservation of a cysteine residue at position 26 in SECcanine; residues at this position have been previously shown to determine subtype-dependent differences in T-cell receptor interactions of other SEs. Overall, these results show that superantigen toxins produced by the multiple members of the genus Staphylococcus are highly conserved in respect to biological and structural properties. Further, the frequent association of SECcanine with pyoderma in dogs supports the notion that the toxins are important for staphylococcal survival and pathogenesis.

Alleles↗
PubMed1995

5' proximal potyviral sequences mediate potato virus X/potyviral synergistic disease in transgenic tobacco.

The interaction of potato virus X (PVX) and potato virus Y (PVY) in tobacco causes a synergistic disease characterized by a dramatic increase in symptom severity, a change in the regulation of PVX RNA replication, and an increase in accumulation of PVX. In this study we demonstrate that PVX also interacts synergistically with three other members of the potyvirus group of plant viruses, tobacco vein mottling virus (TVMV), tobacco etch virus (TEV), and pepper mottle virus. These synergisms resemble the classic PVX/PVY synergism with respect to both the increase in host response and the change in PVX replication. To determine if the induction of PVX/potyviral synergism requires potyviral genome replication per se or if the response is mediated by expression of one or more potyviral genes, we used tobacco plants stably transformed with various subsets of the TVMV genome. PVX infections of transgenic plants expressing the 5'-proximal region of the TVMV genome, including the protease-1, helper component protease, and protein-3 genes, result in symptoms resembling those of PVX/potyviral synergism. A similar synergistic-like response occurs when transgenic tobacco plants expressing the analogous but smaller region from the 5'-proximal region of the TEV genome were infected with PVX. Replication of PVX RNA is altered in transgenic plants expressing 5'-proximal sequences of either TVMV or TEV, and in a manner similar to that observed in double infections. These results indicate that replication of the potyviral genome is not required for PVX/potyviral synergism and that the response is mediated by expression of potyviral sequences which have been localized to the 5'-proximal third of the genomic RNAs of both TVMV and TEV.

Genome, Viral↗
PubMed1995

The complete nucleotide sequence of apple mosaic virus RNA-3.

The complete nucleotide sequence of apple mosaic ilarvirus (ApMV) RNA-3 has been determined from cloned viral cDNAs. The 5' terminus of RNA-3 was determined by direct RNA sequencing, while the 3' end was determined by polyadenylation of genomic RNA and sub-cloning using oligo dT. ApMV RNA-3 is 2056 bases in length and encodes at least two open reading frames. It is similar in size and genome organization to the RNA-3 of other members of the Bromoviridae, which includes ilarviruses. The CP gene is in the 3' half of the molecule, and another large open reading frame is upstream of the CP gene and can potentially encode a protein of 32,400 daltons. This peptide is the same size and shows limited sequence homology to an open reading frame located at the 5' end of RNA 3 in tobacco streak and prune dwarf ilarviruses and alfalfa mosaic virus, which is postulated to be the viral movement protein. The nucleic acid sequence was not homologous to tobacco streak virus, prune dwarf virus, alfalfa mosaic virus or other members of the Bromoviridae. The 5'-non-coding region of ApMV RNA-3 contains a 15 base palindromic sequence which encloses a sequence resembling the ICR-2 regions of eukaryotic tRNA gene promoters.

Amino Acid Sequence↗
PubMed1994

Molecular evidence from 3'-terminus sequence analysis that tobacco vein-banding mosaic virus is a distinct member of the potyvirus group.

The 3'-terminal 1902 nucleotides of the tobacco vein-banding mosaic virus (TVBMV) were cloned and sequenced. The sequence contains a large open reading frame of 572 amino acid residues followed by a non-coding region of 183 nucleotides which terminates in a polyadenylate tract. The TVBMV coat protein is processed from a larger polyprotein by cleavage at a Gln/Gly dipeptide, which is followed closely by the aphid transmission DAG triplet. Translation of the nucleotide sequence yielded a protein of 271 amino acid residues with a calculated M(r) of 30,347. The amino acid and nucleotide sequences of the TVBMV coat protein and 3' non-coding region were compared to 33-35 other virus sequences. Percent sequence identity of the amino acid and nucleotide sequences were in the range expected from comparison of distinct viruses. Phylogenetic analyses were also performed to determine the relationship of TVBMV to other well-characterized viruses. These studies indicate that TVBMV should be regarded as a distinct member of the potyvirus group.

Amino Acid Sequence↗
PubMed1994

The nucleotide sequence of apple mosaic virus coat protein gene has no similarity with other Bromoviridae coat protein genes.

A double-stranded cDNA was synthesized from in vitro polyadenylated apple mosaic virus (ApMV) RNA 3 using oligo(dT) and sequence-specific primers, and was cloned into plasmid vectors. A set of overlapping cDNA clones was used to determine the nucleotide sequence of RNA 4. ApMV RNA 4 was found to contain an open reading frame (ORF) of 666 nucleotides, which was flanked by 5' and 3' non-translated sequences of 55 and 264 nucleotides, respectively. The ORF encoding the coat protein was identified by comparing the predicted amino acid sequence with that obtained from direct protein microsequencing of the native viral coat protein. The ORF encodes a protein with an M(r) of 25,056. The nucleotide sequence of the ApMV coat protein gene showed no similarity to those of alfalfa mosaic virus, tobacco streak virus (TSV), brome mosaic virus or cucumber mosaic virus. The predicted amino acid sequence of the amino-terminal region of the ApMV coat protein is basic, rich in cysteine residues and may contain a zinc finger motif similar to that found in TSV.

Amino Acid Sequence↗
PubMed1993

In vitro destabilization of plant viruses and cDNA synthesis.

DNA copies of a wide range of RNA viruses can be made by the direct addition of appropriately treated, purified virus particles to a reverse transcription reaction. Therefore, many problems associated with RNA isolation can be circumvented. Virus particles can be sufficiently destabilized by adjustments of salt content, buffer, pH or by the use of physical force supplied by a freeze/thaw cycle so that RNA in sufficient quantity and physical condition is available for the synthesis of in some cases, full length cDNAs. cDNAs have been made of viruses in the bromo-, poty-, carla-, ilar-, potex-, tobra and tobamovirus groups. Reported here are experiments with cowpea chlorotic mottle virus and bean common mosaic virus.

Blotting, Southern↗
PubMed1992

The usefulness of aphid transmission as a taxonomic criterion for potyviruses.

In the past vector relationships have been one of the criteria used for delineating plant virus taxa. The proposed family, the Potyviridae, continues that practice. Aphid transmission of viruses within the genus Potyvirus is a useful characteristic in terms of identification, but is of only limited use in terms of taxonomy. This conclusion is based on a greater understanding of the molecular biology of potyviruses. The molecular basis of aphid transmission is not well understood at the present, but these data suggest that, beyond disease diagnosis, virus identification and characterization, and potential identification of genome microheterogeneity, aphid transmission should only be considered as a minor taxonomic criterion.

Animals↗