Mercury (Hg), especially in organic form, is a highly toxic pollutant affecting plants, animals, and man. In plants, the primary target of Hg damage is the chloroplast; Hg inhibits electron transport and photosynthesis. In the present study, chloroplast genetic engineering is used for the first time to our knowledge to enhance the capacity of plants for phytoremediation. This was achieved by in...

Chloroplast protein synthesis in Chlamydomonas reinhardtii is dispensable when cells are provided acetate as a carbon source. Mutants defective in synthesis, assembly, or function of chloroplast ribosomes are therefore conditionally viable. Positive selection of nonphotosynthetic cells on arsenate has been combined with a simple screening procedure to isolate mutants with a broad spectrum of de...

The chloroplast of Chlamydomonas moewusii was examined by electron microscopic and cytochemical methods for the possible presence of DNA. Both the Feulgen reaction and acridine orange indicated the presence within the chloroplast of one or more irregularly shaped DNA-containing bodies generally in the vicinity of the pyrenoid. Electron micrographs revealed 25 A microfibrils in these areas which...

Chloroplasts, the green differentiation form of plastids, are the sites of photosynthesis and other important plant functions. Genetic and genomic technologies have greatly boosted the rate of discovery and functional characterization of chloroplast proteins during the past decade. Indeed, data obtained using high-throughput methodologies, in particular proteomics and transcriptomics, are now r...

Chloroplast biogenesis involves the co-ordinated expression of the chloroplast and nuclear genomes, requiring information to be sent from the developing chloroplasts to the nucleus. This is achieved through retrograde signaling pathways and can be demonstrated experimentally using the photobleaching herbicide, norflurazon, which in seedlings results in chloroplast damage and the reduced express...

Expression of chloramphenicol acetyltransferase (cat) by suitable vectors in chloroplasts of cultured tobacco cells, delivered by high-velocity microprojectiles, is reported here. Several chloroplast expression vectors containing bacterial cat genes, placed under the control of either psbA promoter region from pea (pHD series) or rbcL promoter region from maize (pAC series) have been used in th...

BACKGROUND Antarctic hairgrass (Deschampsia antarctica Desv.) is the only natural grass species in the maritime Antarctic. It has been researched as an important ecological marker and as an extremophile plant for studies on stress tolerance. Despite its importance, little genomic information is available for D. antarctica. Here, we report the complete chloroplast genome, transcriptome profiles ...

The evolution of the endosymbiotic progenitor into the chloroplast organelle was associated with the transfer of numerous chloroplast genes into the nucleus. Hence, inter-organellar signalling, and the co-ordinated expression of sets of nuclear genes, was set up to control the metabolic and developmental status of the chloroplast. Here, we show by the differential-expression analysis of 3,292 g...

We have examined DNA replication in Chlamydomonas reinhardtii chloroplasts in vivo when chloroplast type II topoisomerases are inactivated with sublethal doses of novobiocin. DNA replication is at first inhibited under these conditions. However, after a delay of several hours, chloroplast chromosomes initiate a novobiocin-insensitive mode of DNA replication. This replication starts preferential...

Identification of chloroplast coupling factor particles, by the freeze-etching and negative-staining techniques, was made utilizing chloroplast thylakoids isolated from spinach leaves. Complete removal of particles, comparable in diameter to purified coupling factor particles, from the outer surface of freeze-etched thylakoids was achieved by treatment with 0.8% silicotungstate. Reappearance of...