FS-17

The phenolic profiles of seven monovarietal virgin olive oils (VOOs) - viz. Arbequina, Arbosana, Cornicabra, FS-17, Hojiblanca, Picual and Sikitita - were characterized by using a quantitative strategy based on LC-MS/MS and the selected reaction monitoring (SRM) mode. Data dependent methods, based on precursor ion scanning, product ion scanning and neutral loss scanning, were developed for confirmatory analysis of secoiridoid derivatives. The observed phenolic profiles were used to find correlation between pairs of phenols and similarity trends among the monovarietal VOOs. A Pearson analysis revealed several correlations among phenols with p-value<0.01 and correlation coefficient (R)>0.75 in the seven monovarietal VOOs. Cluster analysis showed two main clusters between VOOs, formed by Arbequina/Hojiblanca/Cornicabra/Picual and Sikitita/Arbosana/FS-17. High correlations (R>0.7) were observed for the following pairs of VOOs: Arbequina/Hojiblanca (R=0.77), essentially supported on levels of hydroxytyrosol acetate (3,4-DHPEA-AC) and dialdehydic forms of secoiridoids; Cornicabra/FS-17 (R=0.81) and Picual/FS-17 (R=0.79), by correlation of flavonoids and secoiridoid derivatives in general. The highest correlation was observed for the pair Picual/Cornicabra (R=0.99). This preliminary study allowed setting similarities and dissimilarities between monovarietal VOOs by analysis of the phenolic profile. The observed connections between phenols for different varieties have been tentatively interpreted according to the main pathways for phenols biosynthesis.

We have observed in a previous study that insertion, deletion and partial frameshift mutation in the distal pre-S region did not abolish replication capacity of the duck hepatitis B virus (DHBV) (Li et al., 1989, J. Virol. 63, 4965-4968). To compare further the relative replication capacity between the pre-S mutant and wild type virus, ducts were infected with either the wild type DHBV strain or a pre-S mutant (FS-17) characterized by a total change of nine consecutive amino acid codons in the distal pre-S region. Compared with the wild type virus, FS-17 exhibited decreased replication capacity whether in separate or mixed infection. The decreased viral replication was correlated with delayed appearance of supercoiled DNA and viral RNA in the hepatocytes. Besides, FS-17 induced persistent viremia when inoculated into 1-day-old ducklings; hence the transient viremia which had been observed in the previous study was probably due to the time delay needed to generate compensatory deletion mutation.