Molecular differentiation of field and vaccine strains of bluetongue virus serotype 2 using the real-time polymerase chain reaction and fluorescene resonance energy transfer hybridisation probes.

As a consequence of the recent outbreaks of bluetongue (BT) disease amongst sheep in the Mediterranean Basin, and following the subsequent vaccination campaign to control further spread of the disease and its long-term maintenance, it has become most important to develop rapid and sensitive methods that can reliably differentiate between field and vaccine strains of the causative virus. The authors describe a new method to differentiate bluetongue virus serotype 2 (BTV-2) field and vaccine strains, using the VP2 gene sequence differences between the South African vaccine and the Italian field wild-type strains. The method is based on the principle that the melting temperature of a DNA duplex gives information on the sequence, which enables the identification of even single-base alterations in the amplicon. The real-time polymerase chain reaction the generation of melting curves and fluorescence detection were all performed using the light cycler system (Roche). Primers and probes were designed using VP2 gene sequences. After RT-PCR, the melting curves analysis, derived by the fluorescence resonance energy transfer (FRET) real-time PCR, was performed using the light cycler data analysis program (Roche). To assess the diagnostic value of the method, a BTV-2 vaccine strain (Onderstepoort Biological Products, South Africa) was first compared against a field strain of BTV-2 (isolated during an outbreak in 2000 in Sardinia). The ability of the method to reliably identify all the BTV-2 strains was tested using an array of eleven BTV-2 field strains isolated during outbreaks in various Italian regions between 2000 and 2002 and other serotypes (BTV-1, BTV-4, BTV-9 and BTV-16) that had been isolated during recent outbreaks of BT in the Mediterranean Basin. The method was clearly able to differentiate BTV-2 strains of vaccine virus from all wild-type strains of the same serotype tested. The resultant melting curves distinctly reveal the two strains to have differing peak values of 47.8 degrees C-/+0.6 degrees C and 60.5 degrees C-/+0.6 degrees C, respectively.

Sequence analysis of a 10.5 kb DNA fragment from the yeast chromosome VII reveals the presence of three new open reading frames and of a tRNAThr gene.

We report the sequence analysis of a 10,531 bp DNA of Saccharomyces cerevisiae chromosome VII. This sequence contains five complete open reading frames (ORFs) potentially encoding proteins longer than 100 amino acids and incomplete ORF encoding for the 3' part of the GCN5 gene (Georgakopoulos and Thireos, 1992). ORFs G9160 and G9155 correspond to the genes ENO1 (Holland et al. 1981) and PUP2 (Gergatsou et al., 1992) respectively. ORF G9165 codes for a protein which shares significant homology with known proteins present in databases (see below). The translated sequence of ORF G9170 shows 88% identity to the 6-phosphogluconate dehydrogenase encoded by the gene 6PGD from S. cerevisiae present in the SwissProt data library (P38720). This indicates that G9170 might code for a second 6-phosphogluconate dehydrogenase. ORF G9175 codes for a putative new member of the mitochondrial carrier family. A hypothetical tRNAThr (TGT) is also present in position 6842-6913.

Cloning and characterization of styrene catabolism genes from Pseudomonas fluorescens ST.

A gene bank from Pseudomonas fluorescens ST was constructed in the broad-host-range cosmid pLAFR3 and mobilized into Pseudomonas putida PaW340. Identification of recombinant cosmids containing the styrene catabolism genes was performed by screening transconjugants for growth on styrene and epoxystyrene. Transposon mutagenesis and subcloning of one of the selected genome fragments have led to the identification of three enzymatic activities: a monooxygenase activity encoded by a 3-kb PstI-EcoRI fragment and an epoxystyrene isomerase activity and an epoxystyrene reductase activity encoded by a 2.3-kb BamHI fragment. Escherichia coli clones containing the 3-kb PstI-EcoRI fragment were able to transform styrene into epoxystyrene, and those containing the 2.3-kb BamHI fragment converted epoxystyrene into phenylacetaldehyde or, only in the presence of glucose, into 2-phenylethanol. The three genes appear to be clustered and are probably encoded by the same DNA strand. In E. coli, expression of the epoxystyrene reductase gene was under the control of its own promoter, whereas the expression of the other two genes was dependent on the presence of an external vector promoter.

Characterization and sequence of a novel insertion sequence, IS1162, from Pseudomonas fluorescens.

We have determined the nucleotide sequence of IS1162, a new insertion sequence (IS) isolated from Pseudomonas fluorescens (Pf) strain ST. This IS element is present in two copies on the pEG plasmid harboured by Pf ST and in a single copy on the chromosome, adjacent to the styrene catabolic genes. IS1162 is 2634 bp in length with 12-bp terminal inverted repeats (IR), and could encode four proteins (ORFs), two for each strand. One strand, Pro1 (62,990 Da), showed a helix-turn-helix motif at the N-terminal region, and Pro2 (25,997 Da) was characterized by the presence of the A and B motives of the NTP (ATP/GTP)-binding site. Comparison of IS1162 of Pf with known IS showed a high homology with IS408 of Burkholderia cepacia [Byrne and Lessie, Plasmid 31 (1994) 138-147]. Pro1 and Pro2 were found to be homologous to the corresponding ORFs of IS408, IS21 [Reimmann et al., Mol. Gen. Genet. 215 (1989) 416-424], IS232 [Menou et al., J. Bacteriol. 172 (1990) 6689-6696] and IS5376 [Xu et al., Plasmid 29 (1993) 1-9]. IS1162 transposed at low frequency and no cointegrates were found among the transposition products. The target duplication sites, variable in length, showed the presence of homologous motives, suggesting a certain degree of specificity of the IS1162 insertion site.

[A new inclusion complex of silibinin and beta-cyclodextrins: in vitro dissolution kinetics and in vivo absorption in comparison with traditional formulations]. / Nuovo complesso di inclusione tra la silibina e la beta-ciclodestrina: velocità di dissoluzione in vitro e assorbimento in vivo in confronto a formulazioni tradizionali.

The very low bioavailability of silybinin, the main constituent of silymarin, so far prevented the development of an oral pharmaceutical specialty based on this active ingredient. To overcome this difficulty, an inclusion complex between Silybinin and beta-Cyclodextrin was prepared. The new complex was compared in vitro tests (dissolution rate) and in a in vivo test (rat bile elimination) with silybinin, silymarin and one traditional formulation based on silybinin. The results show a dramatic increase in the dissolution rate of the complex (> 90% within 5 min) respect to the silybinin that confirm to be practically insoluble (< 5%). The in vivo results agree with the dissolution rates; after administration of the silybinin complex p.o., the silybinin concentration in the rat bile was near 20 times more than after administration of silybinin as is or in a traditional formulation. In the last two cases, the silybinin concentration was even 6 times less than after administration of the same amount of silymarin. These data show that the beta-CD complex solved the problem of the bioavailability of silybinin which, in the traditional formulation utilised as reference, proved to be not bioavailable.

Synthesis and pharmacological evaluation of 2,3-dialkylindoles, "in vitro" inhibitors of thrombin-induced platelet aggregation.

A series of 2,3-dialkylindoles (1-5) have been prepared and tested as antithrombotic agents. The whole class showed in vitro interesting activity in the inhibition of thrombin-induced aggregation. Among these compounds some ones showed activity comparable to standards also in the inhibition of collagen-induced aggregation. Owing to a very fast metabolic degradation through a beta-oxidative mechanism, a drastic decrease of activity in several tests ex vivo or in vivo was observed.