Structural-functional aspects of the postischemic recovery of the hepatocyte endoplasmic network in rats

The experiments on rats have shown that total hepatic ischemia reduces the content of microsomal cytochromes P-450 and b5 and causes amidopyrine and aniline disturbances over a 2-3-week post-ischemic period. The analysis of hepatocyte ultrastructure has revealed the interdependence of structural and functional changes in endoplasmic reticulum during recovery period. The damage of monooxygenase inducibility correlated with stable decline in the number of fixed ribosomes in post-ischemic period.     

High-Speed Recording of Vacuum Arc Discharge Images in the Optical Range

Plasma Physics Reports - Switching of a short vacuum gap with an auxiliary discharge over the surface of a dielectric has been studied via high-speed recording of images of discharge plasma...     

Plantlet regeneration from subculturable nodular callus of Pinus radiata

An efficient planlet regeneration system via nodular callus formation is described for Pinus radiata. Subculturable nodular callus was induced at its highest frequency (93%) on embryonic explants excised from seeds at an early stage of germination (radicle length 2–5 mm). The optimal medium for nodular callus tissue proliferation was LP basal medium that was modified by reducing the concentration of potassium nitrate to 500 mg l^–1 and supplemented with 22.2 M 6-benzyladenine (BAP) and 2.85 M indole-3-butyric acid (IBA). Bud differentiation from the nodules was achieved by reducing BAP and sucrose concentrations in the culture medium. The maximum frequency of adventitious bud formation occurred on LP basal medium containing 2% sucrose and 0.44 M BAP on which about 61% of the transferred nodules formed buds. During the next 6 weeks of culture on the same cytokinin-free medium multiple shoots elongated from the buds. These shoots were excised and transferred to root initiation medium (RIM2.1), consisting of full-stregth SH macro- and micro-salts, 1000 mg l^–1 myo-inositol, 0.4 mg l^–1 thiamine-HCl, 2% sucrose and a combination of naphthaleneacetic acid (NAA), IBA and BAP at concentrations of 2.69, 4.93 and 0.11 M, respectively. After 5–15 days, root meristems were initiated on the stem bases. The highest rooting frequency was achieved when shoots were treated for 10 days on RIM2.1 medium, before being transferred to half-strength Schenk and Hildebrandt medium with 1% sucrose and without growth regulators for root growth.     

Mechanisms for the formation and transport of ion fluxes in the plasma of a high-current vacuum spark

The processes of ion flux formation in the plasma of a high-current vacuum spark were investigated experimentally. It is shown that multicharged ions are generated in the neck formed in the erosion products of the inner electrode. The plasma escaping from the neck region plays a role of a piston dragging particles of the cold peripheral plasma into ambient space. As the discharge current increases, the flux of the evaporated electrode material grows, the degree of ionization of the plasma produced decreases, and the efficiency of plasma heating caused by the pinching effect is reduced.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of <Emphasis Type="Italic">Hyacinthus orientalis</Emphasis> with thaumatin II gene to control fungal diseases

Transgenic plants of hyacinth (Hyacinthus orientalis L.) cvs. Edisson and Chine Pink have been obtained by Agrobacterium-mediated transformation. Leaf explants of the both hyacinth cultivars regenerated shoots on MS medium containing 2.2 μM BAP and 0.3 μM NAA at a frequency of 95%. A. tumefaciens strain CBE21 carrying binary vector pBIThau35 was used for transformation. Plasmid pBIThau35 has been produced by cloning preprothaumatin II cDNA into pBI121 instead of uidA gene. Inoculated leaf explants formed calli and shoots at high frequency on selective medium with 100 mg l⁻¹ kanamycin. Four hyacinth transgenic lines of cv. Chine Pink and one line of cv. Edisson have been selected on medium containing 200 mg l⁻¹ kanamycin. The insertion of thaumatin II gene into hyacinth genome has been confirmed by PCR-analysis. All transgenic plants expressed substantial amounts of thaumatin II (between 0.06 and 0.28% of the total soluble protein). Hyacinth transgenic lines were assayed for resistance to the pathogenic fungi Fusarium culmorum and Botrytis cinerea. There were no significant differences between nontransformed control and transgenic leaves of both cultivars. At the same time the bulbs of the transgenic line Н7401 cv. Chine Pink showed the higher level of resistance to B. cinerea, the bulbs of the transgenic line Н7404 were more resistant to F. culmorum. In both cases the signs of the fungal disease were developed more slowly. The resistance of the bulbs cv. Edisson line to these fungi was not changed. All transgenic hyacinth plant were successfully transferred to soil for further evaluation.     

Overexpression of <Emphasis Type="Italic">AP1-</Emphasis>like genes from <Emphasis Type="Italic">Asteraceae</Emphasis> induces early-flowering in transgenic <Emphasis Type="Italic">Chrysanthemum</Emphasis> plants

Chrysanthemum is one of the most important commercial cut flowers in the world. Early-flowering cultivars are required to produce quality chrysanthemum flowers with a lower cost of production. To shorten the vegetative growth phase of chrysanthemum, three AP1-like genes from Asteraceae were constitutively overexpressed in 80 independent transgenic chrysanthemum lines. All lines were characterized by PCR and RT-PCR and demonstrated that overexpression of compositae AP1-homologs in transgenic chrysanthemum under long-day conditions had no effect on plant development compared to non-transgenic controls. Conversely, under short-day conditions, transgenic plants commenced bud initiation 2 wk earlier than non-transgenic chrysanthemum plants. Subsequently, transgenic chrysanthemum flowers showed color earlier and resulted in full opening of inflorescences 3 wk prior to non-transgenic control plants. These results open new possibilities for genetic improvement and breeding of chrysanthemum cultivars.     

Experimental observation of runaway electrons near the axis of a Z-pinch in a high-<Emphasis Type="Italic">Z</Emphasis> medium

Generation of runaway electrons in the axial region of a Z-pinch (high-current vacuum spark) operating in a high-Z medium was observed experimentally using pulsed optical shadowgraphy and X-ray pinhole imaging.