Introductie van virusresistentie in lelie

Door middel van transformatie via de paicle gun methode was in een voorgaand project resistentie tegen LSV geïntroduceerd in lelie (Lilium longiflorum ‘Snow Queen). In het huidige project werd de resistentie verder onderzocht. De resistentie bleek niet absoluut en niet altijd stabiel (lijnverschillen). Resistentie werd gevonden in de kas en ook in het veld. De twee meest resistente lijnen hadden wat minder groeikracht. Een kastoets gaf goede selectiemogelijkheden. Omdat door strengere regelgeving de aanwezigheid van antibioticumresistentie in de geproduceerde transgene planten marktintroductie onmogelijk maakt, moet het beschikbare manteleiwitgen middels een merkervrije techniek ingebouwd worden. Onderzoek om de resistentie in te bouwen in andere lelies gebruik makend van de L. longiflorum procedure is daarom gestaakt

Ontwikkeling van een protocol voor de transformatie van iris; introductie van resistentie tegen irismozaik viris (IMMV)

Twee iris cultivars, Blue Magic en Blue Sail, werden in weefselkweek gebracht en callus werd geïnduceerd. Dit callus werd genetisch gemodificeerd met virusresistentie via de particle gun procedure die eerder voor lelie was ontwikkeld. Van een van de cultivars, Blue Magic, werden getransformeerde planten in de kas opgekweekt en getoetst op resistentie. De planten waren resistent. De verkregen resistentie was partieel, maar kan verbeterd worden door andere resistentie-mechanismen in te bouwen in plaats van of naast het nu ingebouwde mechanisme. De getransformeerde cultivar is een chimeer en bij transformatie treedt ontmenging van de chimeren op. Het is de vraag of de bijzondere eigenschap van de chimere cultivar behouden blijft. In het veld verkregen sporten zijn waarschijnlijk altijd chimeren. De getransformeerde cultivar kan niet in de praktijk gebruikt worden omdat er naast de virusresistentie ook antibioticumresistentie aanwezig is. Vanwege de verscherpte regelgeving mogen deze planten niet in de open lucht geteeld worden

Measles virus-specific murine T cell clones: characterization of fine specificity function.

Measles virus (MV)-specific murine helper T cell clones (Thy-1.2+, CD4+, CD8-) were generated from mice immunized with MV-infected mouse brain homogenate by limiting dilution and in vitro stimulation of spleen cells with UV-inactivated MV Ag. The protein specificity of 7 out of 37 stable T cell clones, which displayed MHC-restricted MV Ag recognition, could be assessed by using purified MV proteins. Two fusion (F) protein-specific, two hemagglutinin-specific, and three nucleoprotein- or matrix protein-specific clones were shown to be established. The F protein-specific T cell clones together with a pane

Improved method for the isolation of the A and A* proteins of bacteriophage φX174

The A protein (mol. wt 55 000) encoded by the gene A of bacteriophage φX174 is a multifunctional enzyme that is active in the replication of the viral DNA. This protein initiates a rolling circle type of DNA replication by introducing a break in the viral strand of RF1 DNA at the origin of replication. It is the only phage-coded protein necessary for this type of DNA replication and related phages (e.g., G4) use a similar protein

Alstroemeria-infecting cucumber mosaic virus isolates contain additional sequences in the RNA 3 segment.

The coat protein (CP) genes and flanking regions of three alstroemeria-infecting cucumber mosaic virus isolates (CMV-ALS), denoted ALS-LBO, ALS-IPO, and ALS-NAK, were cloned and their nucleotide sequence determined and compared at both nucleic acid and deduced protein level with the published sequences of CMV RNA 3. The sequences of these isolates showed more than 95% nucleotide and peptide sequence homology to each other and to other members of subgroup II CMV. Strikingly, an additional sequence of 218 nt was found in the central region of the 3’-non-translated region (NTR) of RNA 3 of two out of three isolates. The additional sequence appeared to have arisen from RNAs 1 or 2. A subgroup-specific DIG-labeled probe has been developed from this additional sequence and applied to detect subgroup II CMV strains in dot blot hybridization and to differentiate the Alstroemeria isolates containing additional sequences in Northern blot hybridization

Molecular characterization of carla- and potyviruses from Narcissus in China

Conserved carlavirus and potyvirus primers were used in reverse transcriptase-polymerase chain reaction (RT-PCR) to amplify virus fragments from Chinese narcissus (Narcissus tazetta var. chinensis ) in China and the fragments were subsequently sequenced and compared in phylogenetic analyses. Samples from Fujiang province and Shanghai contained either one or two potyviruses and a carlavirus. One potyvirus (PY1) showed a distant relationship to Iris severe mosaic virus, Onion yellow dwarf virus and Shallot yellow stripe virus, while the other (only in the Fujiang sample, PY2) was most closely related to Turnip mosaic virus (TuMV). Similar experiments using glasshouse grown Narcissus originating from the UK contained Ornithogalum mosaic virus and another potyvirus (PY3) in the TuMV/PY2 cluster. Comparisons with previously determined sequence fragments indicated that PY2 was probably Narcissus yellow stripe virus and PY3 Narcissus late season yellow virus. Carlavirus fragments from both Chinese sites seemed to be of the same virus, which was most closely related in phylogenetic analyses to Potato virus M, Aconitum latent virus and Hop latent virus. It is most probably a new member of the genus Carlavirus and has been tentatively named Narcissus common latent virus