Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

Lecithotrophic development and metamorphosis in the Indo-West Pacific brittle star Ophiomastix venosa (Echinodermata: Ophiuroidea)

Summary

The larval development of the ophiocomid ophiuroid Ophiomastix venosais described using SEM. The gastrula transforms into a uniformly ciliated early larva which progressively changes into a lecithotrophic late premetamorphic larva with a continuous bilateral ciliated band. This stage is short-lived and equivalent to a highly reduced ophiopluteus. Comparisons between O. venosa and other ophiuroid species whose development has been investigated suggest that, whatever the developmental mode (lecithotrophic or planktotrophic), a pluteus stage always occurs in ophiuroids with planktonic development. Two metamorphic stages were identified, the late metamorphic larva differing from the early one by the closure of the larval mouth. The appearance of the permanent mouth marks the end of the metamorphosis. The postlarva still possesses remnants of larval features. The transformation of the reduced ophiopluteus into a barrel-shaped metamorphic larva with transverse ciliated bands, a vitellaria larva, is followed. The possible occurrence of a unique type of metamorphic larva in non-brooding ophiuroids is discussed. Verification of this, however, needs further SEM investigations on metamorphic larva from species having “regular” planktotrophic development.     

Agrobacterium-mediated in planta transformation of maize via pistil filaments

Integration of T-DNA into the maize genome as a result of treatment of silks with Agrobacterium cells, containing activated vir genes, was demonstrated. In planta treatment of maize (Zea mays L.) was performed during flowering in field. Cell suspension of Agrobacterium tumefaciens line GV3101(pTd33), carrying activated vir genes, was applied onto the previously isolated silks, which were afterwards pollinated with the pollen of the same cultivar. Integration of T-DNA into maize genome was confirmed by PCR (the nptII and gus reporter genes) and hystochemical staining of the seedling tissues, obtained from the transformed seeds. Amplification of the nptII gene showed the presence of about 60.3% of PCR-positive plants out of the total number of kanamycin-resistant seedlings examined, or 6.8% of the total of number of seedlings.     

Mouse oocyte maturation in vitro at a low concentration of pyruvate in the culture medium

Mouse oocytes isolated from antrum--containing follicles were cultivated for 17-19 hours in the media with different concentrations of pyruvate. Decrease of pyruvate concentration down to 0.03 mM significantly increased the number of oocytes with intact germinal vesicles. However, in 50% of oocytes desintegration of nuclear membrane and condensation of chromosomes occurred even at a concentration of 0.02 mM.     

Production of miniantibodies to Agrobacterium tumefaciens VirE2 virulence protein by the method of phage display

The scFv miniantibodies to the recombinant protein VirE2 from Agrobacterium tumefaciens were obtained by the method of phage display. The miniantibodies were purified and tested using timmunodot method for binding to a recombinant protein from Escherichia coli and to the native protein VirE2 from A. tumefaciens. The functional activity of the miniantibodies was comparable to the activity of mouse polyclonal antibodies against the VirE2 protein.