The enzymatic sequence responsible for the biosynthesis of tetracyclic quinolizidine alkaloids could be localized in chloroplasts isolated from Lupinus polyphyllus leaves and L. albus seedlings by differential centrifugation. Upon feeding of cadaverine to isolated chloroplasts lupanine is produced as the main alkaloid. Chloroplasts treated with digitonine produce sparteine and 17oxosparteine in...

Abstract C4 plants, such as maize, strictly compartmentalize Rubisco to bundle sheath chloroplasts. The molecular basis for the restriction of from more abundant mesophyll chloroplasts is not fully understood. Mesophyll transcribe large subunit gene and, when normally quiescent transcription nuclear small family overcome by ectopic expression, still do accumulate measurable Rubisco. Here we sho...

Etioplasts capable of incorporating (14)C-leucine into protein have been isolated from dark-grown pea and wheat plants. The requirements for leucine incorporation for etioplasts were similar to those for chloroplasts. An ATP-generating system, Mg(2+), and GTP were required. The amino-acid-incorporation activity of etioplasts from wheat was comparable to that of chloroplasts on an RNA basis, whe...

During attempts to prepare active fragments of spinach chloroplasts, we observed major losses of phosphorylative activity following suspension of the chloroplasts in water. This damage was traced to treatments which probably had the effect of removing cations from the chloroplasts, rather than to a simple physical disruption. Indeed, chloroplast fragments have been used successfully in studies ...

The potato mop-top virus (PMTV) triple gene block 2 (TGB2) movement proteins fused to monomeric red fluorescent protein (mRFP-TGB2) was expressed under the control of the PMTV subgenomic promoter from a PMTV vector. The subcellular localizations and interactions of mRFP-TGB2 were investigated using confocal imaging [confocal laser-scanning microscope, (CLSM)] and biochemical analysis. The resul...

1. Exposure of chloroplasts to sonic oscillation in a medium of low osmolarity rapidly inactivated the Hill reaction, photophosphorylation, and photooxidation of ascorbate in the presence of dichlorophenyl-1 , 1 -dimethylurea. Concurrently with this inactivation plastocyanin was liberated from the chloroplasts. The addition of plastocyanin during sonic oscillation prevented net loss of plastocy...

The activity of NADP and O(2) photoreduction by water is essentially higher in chloroplasts isolated from pea seedlings (Pisum sativum L.) grown under blue light as compared with that from plants grown under red light. In contrast, the photoreduction of NADP and O(2) with photosystem I only is practically the same or even lower in chloroplasts isolated from plants grown under blue light. The ad...

Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2) is the only phosphatase that is dual-targeted to both chloroplasts and mitochondria. Like Toc33/34 of the TOC and Tom 20 of the TOM, AtPAP2 is anchored to the outer membranes of chloroplasts and mitochondria via a hydrophobic C-terminal motif. AtPAP2 on the mitochondria was previously shown to recognize the presequences of several nuclear-...

We describe a novel, typically prokaryotic, sensor kinase in chloroplasts of green plants. The gene for this chloroplast sensor kinase (CSK) is found in cyanobacteria, prokaryotes from which chloroplasts evolved. The CSK gene has moved, during evolution, from the ancestral chloroplast to the nuclear genomes of eukaryotic algae and green plants. The CSK protein is now synthesised in the cytosol ...