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R Koenig

Publications and source records attributed to R Koenig.

At least 73 records · Page 4Linked to original sources
PubMed2000

Deletions in the KTER-encoding domain, which is needed for Polymyxa transmission, in manually transmitted isolates of Beet necrotic yellow vein benyvirus.

One A and one B type isolate of Beet necrotic yellow vein benyvirus which had been passaged for more than 15 years on manually inoculated Chenopodium quinoa in our laboratory were found to have small deletions in the KTER-encoding domain on RNA 2 which is necessary for Polymyxa transmission. There were no indications that these isolates and a third one, in which intact RNA 2 was detected, contained mixtures of deleted and intact RNAs or that populations of RNAs 2 with different deletions including very large ones were present.

Amino Acid Sequence↗
PubMed2000

Improved detection of Beet necrotic yellow vein virus in a DAS ELISA by means of antibody single chain fragments (scFv) which were selected to protease-stable epitopes from phage display libraries.

The detection of Beet necrotic yellow vein virus (BNYVV) in stored sugar beets by means of monoclonal antibodies or antibody single chain fragments (scFv) often poses problems, because the immunodominant C-terminal epitope of the viral coat protein is readily lost due to proteolysis. Clones which produce scFv specific for protease-stable BNYVV epitopes were selected from two naive phage display libraries. Fusion proteins of the scFv with a human IgG kappa chain (expressed from the newly designed vector pCL) or with alkaline phosphatase,respectively, allow the ELISA detection of BNYVV even in stored sugar beets with a sensitivity which was comparable or often higher than that achieved with polyclonal antibodies.

Antibodies, Monoclonal↗
PubMed2000

Soil-borne rye mosaic and European wheat mosaic virus: two names for a furovirus with variable genome properties which is widely distributed in several cereal crops in Europe.

PCR and nucleotide sequence analyses have revealed that Soil-borne rye mosaic furovirus (SBRMV) which we have recently described is widely distributed in Europe. In Northern Germany, Poland and Denmark the virus affects mainly rye and triticale, but in France and Italy it is wheat which becomes infected. The partial RNA 1 and RNA 2 sequences which were determined for the various SBRMV sources form several clusters, but so far no correlation between molecular differences and the type of host which becomes infected under natural conditions was detected. European wheat mosaic furovirus which was recently described by Diao et al. (1999) [Virology 261: 331-339] is closely related to a French source of SBRMV.

Base Sequence↗
PubMed2000

Molecular analyses of European A, B and P type sources of Beet necrotic yellow vein virus and detection of the rare P type in Kazakhstan.

Nucleotide sequence analyses revealed that the genomes of the various European types of Beet necrotic yellow vein virus (BNYVV), i.e. the A, B and P types, are strongly conserved. Almost identical sequences were found, for instance, for A types originating from The Netherlands, Italy and former Yugoslavia; these sequences were also almost identical to those determined c. 15 years ago by Bouzoubaa et al. (1985; 1986 and 1987). This sequence stability of BNYVV types is in contrast to a pronounced sequence variability observed with Beet soil-borne pomovirus, another Polymyxa-transmitted sugar beet virus with rod-shaped particles. Sequences of RNA 1, 2 and 4 of BNYVV sources from Kazakhstan were almost identical to those of the P type of BNYVV which so far had been found only in a small area around the French town of Pithiviers. RNA 5, which in Europe is found also only in the Pithiviers area, was detected in the bait plants grown in two out of three soil samples from different fields in Kazakhstan. It closely resembled RNA 5 from the Pithiviers area, but was very different from RNA 5 from various East Asian BNYVV sources.

Chenopodiaceae↗
PubMed2000

Structure and variability of the 3' end of RNA 3 of Beet soil-borne pomovirus--a virus with uncertain pathogenic effects.

PCR products representing c. 550 3' terminal bases of Beet soil-borne pomovirus (BSBV) RNA 3 were compared for sources of this virus from all major sugarbeet-growing areas in Germany. In none of these areas conspicious symptoms could be attributed to the presence of BSBV. Single strand conformation polymorphism analyses suggested that the BSBV genome may be very variable. This was confirmed by nucleotide sequence analysis. Each PCR product which was analysed showed sequence differences to others. Even the PCR products obtained from plants grown in the same soil sample were different. The highly variable nature of the BSBV genome is in contrast to the much more conserved nature of the Beet necrotic yellow vein virus genome. By means of the STAR programme a secondary structure was predicted for the 3' end of BSBV RNA 3, in which some areas are highly conserved, whereas others are characterized by a clustering of nucleotide exchanges.

3' Untranslated Regions↗
PubMed1999

Genetic analysis of large-sized RNA 2 species of a TCM-like tobacco rattle virus source from spinach.

RNA 2 of a tobacco rattle virus isolate from spinach (TRV SP) resembles that of a recently described isolate from onion (TRV ON), but its ORF 3 is much larger. Naturally infected spinach apparently contains a second TRV SP RNA 2 species with a partially deleted ORF 3 and an RNA 1-like 3'-end which consists of c. 1500 nts and thus is much longer than in any other tobravirus RNA 2 sequenced so far. RNAs 2 of TRV SP and ON are closely related to that of TRV TCM from tulip, but besides the additional ORF 3 they have longer 5'-UTRs with two GCAUA motifs and different coat protein C-termini. The high percentage of amino acid sequence identity in the coat proteins of the TCM-like tobraviruses suggests that they may be considered as strains of a distinct virus species. Possible pitfalls in the use of serology in tobravirus classification are discussed.

5' Untranslated Regions↗
PubMed1999

Molecular characterization of a new furovirus mainly infecting rye.

The complete or almost complete nucleotide sequences were determined for the two RNAs of three different sources of a new furovirus which mainly infects rye and for which the name Soil-borne rye mosaic furovirus (SBRMV) is proposed. The genome organization of this virus is virtually identical to that of Soil-borne wheat mosaic furovirus (SBWMV). However, SBRMV and SBWMV differ considerably in the nucleotide sequences of their genomes and in the derived amino acid sequences of their putative gene products. The sequences of the three sources of SBRMV (two from rye and one from wheat) differ between each other in various parts of their genomes by 1% to 10%. Larger differences were found in the readthrough part of the coat protein readthrough protein. There are no indications that the relationship of the C source from wheat to the other two sources from rye is more distant than the relationship between the two sources from rye. The 3'UTRs of both SBRMV RNAs are remarkable in having a predicted upstream pseudoknot domain (UPD) with seven pseudoknots. The same number was also predicted for the UPD of SBWMV RNA 1 whereas the much shorter UDP of SBWMV RNA 2 may form only four pseudoknots.

3' Untranslated Regions↗
PubMed1999

Detection and nucleotide analysis of RNA5 of beet necrotic yellow vein virus isolated in China.

Using the RT-PCR method, five isolates of beet necrotic yellow vein virus from China were used for the RNA5 genomic component detection and sequence analysis. The result showed that RNA5 was only found in the isolates from Baotou and Hohhot, but not in those of Xingjiang, Helongjiang, and Wulate of Inner Mongolia. The RNA5 components had 1338 nucleotides and 1358 nucleotides in the length of Baotou and Hohhot isolates, respectively, in which the single open reading frame (ORF) encoding for a proteins of 26kD were contained. Compared with the published sequences of F72 and D5 isolates, these RNA5 components shared the identity of 93.7% approximately 98.5% in nucleotide acids and 91.8%-98.2% in deduced amino acids.

Base Sequence↗