Stable wheat transformation obtained without selectable markers.

Transgenic wheat plants without the selectable marker gene were obtained either in the presence or in the absence of selective pressure during the transformation protocol. When using hygromycin as selective agent in a co-transformation experiment involving a mixture of plasmids pGL2, containing the hpt gene, and pAI1Gus, containing the uidA gene, 3 out of 19 transgenic wheat plants had the uidA gene alone as shown by Southern blots. The gene was transmitted to the progeny following Mendelian rules.

Hygromycin resistance as an efficient selectable marker for wheat stable transformation.

A highly efficient method for stable wheat transformation using hygromycin resistance as a selectable marker is described. Young embryogenic calli growing from immature wheat embryos were transformed using a gunpowder-driven microparticle accelerator. Transgenic wheat plants were determined by PCR amplification of transgene fragments and confirmed by Southern hybridization, activity of the transgene expression and by analysis of the progeny.

Changes in activity and structure of the chloroplast proton ATPase induced by illumination of spinach leaves.

Photophosphorylating activity of chloroplasts rapidly prepared from preilluminated spinach leaves was higher than the activity of chlorplasts from leaves kept in the dark. Higher Vmax values were obtained with the former when either ADP or Pi concentrations were varied. The rate of decay of the in vivo light-activated Mg2+-ATPase was highly dependent on temperature, increasing with it.

Sulfhydryl groups in photosynthetic energy conservation. VI. Subunit distribution of sulfhydryl groups and disulfide bonds in chloroplast coupling factor and ATPase activity.

The subunit distribution of sulfhydryl groups and disulfide bonds of spinach chloroplasts coupling factor I has been determined. Native coupling factor I with a latent ATPase activity has eight sulfhydryl groups distributed 4 : 2 : 0 : 0 : 2 in the alpha, beta, gamma, delta and epsilon subunits, respectively. Heat treatment of coupling factor I, in addition to the activation of its ATPase activity, induces a dithiol-disulfide interchange between the gamma and the alpha subunit, changing the sulfhydryl groups' distribution to 2 : 2 : 2 : 0 : 2.

Sulphydryl groups in photosynthetic energy conservation. V. Localization of the new disulfide bridges formed by o-iodosobenzoate in coupling factor of spinach chloroplasts.

1. Chemical modification by o-iodosobenzoate of soluble chloroplast coupling factor 1 (CF1) during heat activation resulted in inhibition of its Ca-ATPase activity and in the formation of two new intrapeptide disulfide bridges as suggested by: (a) the disappearance of three out of four accessible thiol groups, two from gamma and one from a beta subunit as a consequence of CF1 modification by o-iodosobenzoate; (b) the total free sulphydryl groups of CF1 were reduced from 8 to 4 after modification of CF1 by o-iodosobenzoate. Two groups disappeared from beta and two from gamma subunits; (c) a second heating step of CF1 in the presence of 10 mM dithioerythritol reversed the inhibition of the ATPase and reduced both the newly formed disulfide bridges and those present in native CF1.