Most of the estimated 1000 or so chloroplast proteins are synthesized as cytosolic preproteins with N-terminal cleavable targeting sequences (transit peptide). Translocon complexes at the outer (Toc) and inner chloroplast envelope membrane (Tic) concertedly facilitate post-translational import of preproteins into the chloroplast. Three components, the Toc34 and Toc159 GTPases together with the ...

An in vitro system has been developed that allows the formation of translation initiation complexes with Euglena chloroplast 30S ribosomal subunits and natural mRNAs. For these experiments two regions of the Euglena chloroplast genome have been cloned behind the T7 transcriptional promoter and the corresponding RNAs synthesized in vitro. These mRNAs are capable of forming initiation complexes w...

CPD45 (chloroplast division45),which is also known as FHY3 (far-red elongated hypocotyl3), is a key factor in the far-red light signaling pathway in Arabidopsis. We previously showed that FHY3/CPD45 also regulates chloroplast division. Because light is also a regulator of chloroplast development and division, we sought to clarify the relationship between far-red light signaling and chloroplast ...

Phototropins are plant photoreceptors which regulate numerous responses to blue light, including chloroplast relocation. Weak blue light induces chloroplast accumulation, whereas strong light leads to an avoidance response. Two Arabidopsis phototropins are characterized by different light sensitivities. Under continuous light, both can elicit chloroplast accumulation, but the avoidance response...

During the course of green plant evolution, numerous light responses have arisen that optimize their growth under fluctuating light conditions. The blue light receptor phototropin mediates several photomovement responses at the tissue, cellular and organelle levels. Chloroplast photorelocation movement is one such photomovement response, and is found not only in most green plants, but also in s...

Plant chloroplasts contain an intricate photosynthetic membrane system, the thylakoids, and are surrounded by two envelope membranes at which thylakoid lipids are assembled. The glycoglycerolipids mono- and digalactosyldiacylglycerol, and sulfoquinovosyldiacylglycerol as well as phosphatidylglycerol, are present in thylakoid membranes, giving them a unique composition. Fatty acids are synthesiz...

the genus artemisia containing more than 500 taxa at the specific or subspecific level. thirty-four species of genus artemisia have been reported in iran, which from the viewpoint distribution, density and coverage is the most important genera of plant. since the still has not been achieved a general system for the classification and phylogeny, in this research tried with evaluation of chloropl...

The chloroplast DNA of wild-type Chlamydomonas reinhardtii was isolated in a CsCl density gradient as a single, homogeneous density class with a mean density of 1.695 g/cm(3). Irrespective of sheared size, denatured chloroplast DNA renatured as a single homogeneous species. Compositional heterogeneity, presumably intramolecular, was revealed by the absorbance-temperature profile. The complement...

Chloroplast retrograde signals play important roles in coordinating the plastid and nuclear gene expression and are critical for proper chloroplast biogenesis and for maintaining optimal chloroplast functions in response to environmental changes in plants. Until now, the signals and the mechanisms for retrograde signalling remain poorly understood. Here we identify factors that allow the nucleu...

Wild-type cells of the unicellular green alga Chlamydomonas reinhardi have been grown for several generations in the presence of rifampicin, an inhibitor of chloroplast DNA-dependent RNA polymerase, spectinomycin and chloramphenicol, two inhibitors of protein synthesis on chloroplast ribosomes, and cycloheximide, an inhibitor of protein synthesis on cytoplasmic ribosomes. The effects of cyclohe...