Uphill Accumulation of Ionic Species into a Lipid Vesicle by the Concentration Gradient of Counter Ions.

The "uphill (against the concentration gradient)" accumulation of a hydrophobic cation (rhodamine 6G, R6G+) into the inner phase of a giant unilamellar vesicle (GUV) was realized with the concentration gradient of the counter anion (X- = ClO4-, BF4-, or Br-) in the presence of phosphate buffer (P-, pH = 7) in the inner and outer phase of the GUV and detected as the increase of the R6G+ fluorescence intensity in the inner phase using a confocal laser scanning fluorescence microscope. The addition of X- in the outer phase of the GUV caused the accumulation of R6G+ in the inner phase. The degree and kinetics of the accumulation were dependent on the concentration and type of X-; e.g., the inner concentration of R6G+ reached 2.5 times that in the outer phase of GUV after adding 10 mM ClO4-. The accumulation was theoretically simulated by assuming the distribution of ion pairs (R6G+ and X-, R6G+, and P-) between the aqueous phase and the lipid bilayer membrane (ion pair distribution model) and the transmembrane fluxes of R6G+, X- and P-. The theoretical simulation rationalized the accumulation degree and kinetics of the experimental results. The accumulation of the target cation by the concentration gradient of the counter anion demonstrated in this study can be an effective method for the preparation of liposomal drugs.

Gentian (Gentiana triflora) prevents transmission of apple latent spherical virus (ALSV) vector to progeny seeds.

MAIN CONCLUSION: Gentian plants ( Gentiana triflora ) severely restrict apple latent spherical virus (ALSV) invasion to the gametes (pollens and ovules) and block seed transmission to progeny plants. Early flowering of horticultural plants can be induced by infection of ALSV vector expressing Flowering Locus T (FT) gene. In the present study, flowering of gentian plants was induced by infection with an ALSV vector expressing a gentian FT gene and the patterns of seed transmission of ALSV in gentian were compared with those in apple and Nicotiana benthamiana. Infection of gentian progeny plants with ALSV was examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), reverse transcription-loop-mediated isothermal amplification (RT-LAMP), and enzyme-linked immunosorbent assay (ELISA). ALSV was not transmitted to the progeny gentian plants, whereas small proportions of apple and N. benthamiana progeny plants are infected with ALSV. The in situ hybridization analyses indicated that ALSVs are not present in gentian pollen and ovules, but detected in most of gametes in apple and N. benthamiana. Collectively, these results suggest that seed transmission of ALSV is blocked in gentian plants through the unknown barriers present in their gametes. On the other hand, apple and N. benthamiana seem to minimize ALSV seed transmission by inhibiting viral propagation in embryos.