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M Síp

Publications and source records attributed to M Síp.

9 recordsLinked to original sources

DNA microarray: parallel detection of potato viruses.

DNA microarray assay has become a useful tool for gene expression studies. Less frequent is its application to detection of viruses or diagnostics of virus diseases. Here we show design of a microscope slide-based microarray assay for simultaneous identification of several potato viruses. Different primer pairs were designed or adopted to obtain specific amplicons from six potato viruses: Potato virus A (PVA), Potato virus S (PVS), Potato virus X (PVX), Potato virus Y (PVY), Potato mop-top virus (PMTV) and Potato leaf-roll virus (PLRV). Purified viral DNA probes were spotted on a microscope slide coated with poly-L-lysine. The same primers were used for preparation of fluorochrome-labeled targets. The latter were denatured and hybridized on the microarray slide (chip). An example of simultaneous assay of two pathogens is given and possibilities of practical application of this type of assay are discussed.

DNA Primers↗

Preferential banding of secondary veins in strawberry is caused by mixed virus infection.

Leaves of Fragaria ananassa Duch. cv. Redgauntlet with mottle and mild dwarf symptoms were grafted onto F. vesca indicator clones. The youngest leaves developed specific vein banding pattern located preferentially on secondary veins near the edge of the leaves. Electron microscopy of ultrathin sections and negatively stained purified virus preparations from symptom-bearing strawberry leaves revealed presence of different-sized isometric virions. Particles of about 50 nm and 23 nm in diameter were identified as strawberry vein banding virus (SVBV) and tobacco necrosis virus (TNV) D strain. Based on results of electron microscopy, DNA hybridization, enzyme-linked immunosorbent assay (ELISA), and DNA sequencing we propose that the anomalous "leaf edge vein banding" symptoms are caused by a mixed virus infection with SVBV and other viruses such as TNV.

Caulimovirus↗

Detection of strawberry vein banding virus by polymerase chain reaction and dot blot hybridization.

Strawberry vein banding virus (SVBV) is one of seventeen members of the family Caulimoviridae. Natural infection with the virus is known in Fragaria species only. Infections caused by SVBV are often symptomless (1), but their significance increases in mixed infections with strawberry crinkle or strawberry latent C viruses (2,3). This virus has been originally found on strawberries in USA and firstly described by Frazier (4), but it is probably world-wide distributed by planting or breeding materials. SVBV has been observed on cultivated strawberries in North America, Australia, Brazil, Japan (5) and recently in Europe (6,7). The concentration of SVBV in infected plants is usually very low. Its detection by ELISA is impossible because of lack of specific antibodies. Evidence of the caulimovirus nature of SVBV has been confirmed by its circular dsDNA genome, shape and size of viral particles (8), presence of cytoplasmic inclusion bodies typical for caulimoviruses, and distant serological relationship with cauliflower mosaic virus (CaMV, 9). In this paper we present detection of SVBV by combination of two detection methods--polymerase chain reaction (PCR) and dot blot hybridization with a non-radioactive probe.

Caulimovirus↗

Diagnosis of strawberry vein banding virus by a non-radioactive probe.

A non-radioactive digoxigenin-labelled cDNA probe was prepared from genomic DNA of American isolate No. 45058 of strawberry vein banding virus (SVBV). Five different air-dried SVBV-containing strawberry leaf samples originating from National Clonal Germplasm Repository, Corvallis, USA, reacted positively in dot blot hybridization with this probe. Six of twelve strawberry samples from the Czech Republic exhibiting symptoms of SVBV-like infection gave positive reaction with this probe. Our results confirm the spread of SVBV in Central Europe and introduce the first reliable screening method for this virus.

DNA Probes↗

DNA conformational change produced by the site-specific interstrand cross-link of trans-diamminedichloroplatinum(II).

The DNA distortion produced by the interstrand cross-link of trans-diamminedichloroplatinum-(II) has been described by means of gel electrophoresis, chemical probes, and molecular mechanics modeling. Synthetic double-stranded oligodeoxyribonucleotides of varying lengths (19-22 base pairs) were synthesized that contained a unique site-specific interstrand cross-link within their central sequence d(TGCT)/d(AGCT) between complementary guanine and cytosine residues. We find that the platinated deoxyriboguanosine residue adopts syn conformation. The duplex is distorted on both sides of the cross-link, but the bases are still paired. The distortion introduces some flexibility into the helix. In addition, the double helix is unwound and bent toward the major groove.

Base Sequence↗

Transmembrane potential measurement with carbocyanine dye diS-C3-(5): fast fluorescence decay studies.

The mechanism of carbocyanine dye diS-C3-(5) fluorescence intensity variations with transmembrane potential changes has been studied using time-resolved fluorescence spectroscopy. Clear evidence is given of the transmembrane-potential-dependent partition of the dye among various sites with different fluorescence lifetimes. It was found that fluorescence decay profiles reflect the transmembrane potential changes.

Benzothiazoles↗

Influence of hyperbaric oxygenation on bilirubin and ditaurobilirubin auto-oxidation and porphyrin-sensitized photo-oxidation.

Oxygen concentration controls the reaction rate of porphyrin-sensitized photo-oxidation under constant experimental conditions. The rate of bilirubin and ditaurobilirubin auto-oxidation and meso-tetra-(4-sulphonatophenyl) porphine-sensitized photo-oxidation in aqueous solution increases by about 3.5 times in 0.5 MPa of oxygen. Use of hyperbaric oxygenation in the photodynamic therapy of tumours and in the phototherapy of jaundice is proposed.

Bilirubin↗