Species-dependent expression of the hyoscyamine 6 beta-hydroxylase gene in the pericycle.

The tropane alkaloid scopolamine is synthesized in the pericycle of branch roots in certain species of the Solanaceae. The enzyme responsible for the synthesis of scopolamine from hyoscyamine is hyoscyamine 6 beta-hydroxylase (H6H). The gene for H6H was isolated from Hyoscyamus niger. It has an exon/intron organization very similar to those for ethylene-forming enzymes, suggesting a common evolutionary origin. The 827-bp 5' flanking region of the H6H gene was fused to the beta-glucuronidase (GUS) reporter gene and transferred to three solanaceous species by Agrobacterium-mediated transformation systems: H. niger and belladonna (Atropa belladonna), which have high and low levels, respectively, of H6H mRNA in the root, and tobacco (Nicotiana tabacum), which has no endogenous H6H gene. Histochemical analysis showed that GUS expression occurred in the pericycle and at the root meristem of transgenic H. niger hairy roots, but only at the root meristem of transgenic H. niger hairy roots, but only at the root meristem of hairy roots and plants of transgenic tobacco. In transgenic hairy roots and regenerated plants of belladonna, the root meristem was stained with GUS activity, except for a few transformants in which the vascular cylinder was also stained. These studies indicate that the cell-specific expression of the H6H gene is controlled by some genetic regulation specific to scopolamine-producing plants.     

Mapping of the human gene encoding the mutual signal-transducing subunit (β-chain) of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and interleukin-5 (IL-5) receptor complexes to chromosome 22q13.1

The human gene encoding the mutual signal-transducing subunit (-chain) of granulocyte-macrophage colony-stimulating factor, interleukin-3, and interleukin-5 receptor complexes has been mapped to chromosome 22q13.1 by the fluorescence in situ hybridization method.     

Human high-affinity FcγRI (CD64) gene mapped to chromosome 1q21.2-q21.3 by fluorescence in situ hybridization

The human FcRI gene encodes for a highaffinity Fc receptor that plays pivotal roles in the immune response. We have used fluorescence in situ hybridization analysis to localize the FcRI gene to human chromosome 1. The human FcRI (CD64) gene has been assigned to human chromosome 1q21.2-q21.3 using R-banded human (pro)metaphase chromosomes.     

Effects of hydrostatic pressure on the ultrastructure and leakage of internal substances in the yeast Saccharomyces cerevisiae

The structural damage to and leakage of internal substances from Saccharomyces cerevisiae 0–39 cells induced by hydrostatic pressure were investigated. By scanning electron microscopy, yeast cells treated at room temperature with pressuresbellw 400 MPa for 10 min showed a slight alteration in outer shape. Transmission electron microscopy, however, showed that the inner structure of the cell began to be affected, especially the nuclear membrane, when treated with hydrostatic pressure around 100 MPa at room temperature for 10 min; at more than 400–600 MPa, further alterations appeared in the mitochondria and cytoplasm. Furthermore, when high pressure treatment was carried out at — 20° C, the inner structure of the cells was severely damaged even at 200 MPa, and almost all of the nuclear membrane disappeared, although the fluorescent nucleus in the cytoplasm was visible by 4,6-diamidino-2-phenylindole (DAPI) staining. The structural damage of pressure-treated cells was accompanied by the leakage of internal substances. The efflux of UV-absorbing substances including amino acid pools, peptides, and metal ions increased with increase in pressure up to 600 MPa. In particular, amounts of individual metal ion release varied with the magnitude of hydrostatic pressures over 300 MPa, which suggests that the ions can be removed from the yeast cells separately by hydrostatic pressure treatment. Correspondence to: S. Shimada     

Movement of actin away from the center of reconstituted rabbit myosin filament is slower than in the opposite direction.

By decreasing ionic strength slowly, thick filaments of several micrometers in length were obtained from purified rabbit skeletal muscle myosin. Dark-field observation showed these filaments with their center scattering light extensively. Active movement of actin filaments complexed with tetramethyl rhodamine-phalloidin along the reconstituted myosin filaments was observed. Actin filaments moved towards the center of myosin filaments at a speed of 3.9 +/- 1.6 microns s-1 (mean +/- SD, n = 40) and often continued to move beyond the center towards the tip of the opposite side at a lower speed. The speed of the movement away from the center was 1.0 +/- 0.6 microns s-1 (n = 59). Thus, the functional bipolarity in terms of the movement speed which was first found in native thick filaments of molluscan smooth muscle is also seen in reconstituted filaments from purified rabbit skeletal muscle myosin. The difference of the speed between the two directions is considered to be due to properties of myosin molecules themselves.