Search results for "Chloroplast"

Phylogeny of snapdragon species (Antirrhinum; Scrophulariaceae) using non-coding cpDNA sequences

2005

Antirrhinum is an Old World genus of up to 25 perennial taxa, mainly located in the western Mediterranean basin. A molecular analysis of 24 taxa of Antirrhinum was undertaken using cpDNA sequences from the trnT (UGU)-trnL (UAA) 5' exon region. The Kimura two-parameter model was chosen to calculate pairwise nucleotide divergence values between cpDNA sequences, and a bootstrapped neighbor-joining dendrogram was constructed from the nucleotide divergence distance matrix. Eighteen sites were variable across the studied samples and the position of 7 indels, ranging from 1 to 7 bp, was inferred from the sequence alignment. Several trnT-trnL sequences are identical in: some members of subsection K…

Screening for Solute Transporters in Plant Photosynthetic Membranes

2008

As compared to chloroplast envelope transporters, the field of thylakoid transporters is largely unexplored. There is evidence for several transport activities in the plant thylakoid membrane, but only a copper P-type ATPase and an ATP/ADP carrier have been so far identified at the gene level in Arabidopsis thaliana. Using in silico analyses, we have predicted the existence of approximately 15 thylakoid transporters, including phosphate transporters and cation channels. For experimental validation, we have used peptide- specific antibodies and functional analyses in heterologous system. These novel data are highly relevant to understand the transport network of the thylakoid membrane and it…

Ultrastructure and freeze-fracture studies of the thylakoids ofMantoniella squamata (Prasinophyceae)

1988

The ultrastructure and the supramolecular organization of the thylakoids of the small green flagellate,Mantoniella squamata, were examined in thin sections and freeze-fracture preparations. The whole chloroplast is tightly packed with thylakoids, which show a pattern of meandering, branching and/or anastomosing membranes. In freeze-fracture preparations only two fracture-faces can be distinguished: the PF- and the EF-face. The PF-face has a much higher particle density than the EF-face (PF: 4086 particles/μm2; EF: 865 particles/μm2). The EF-face is not as uniform as the PF-face. The areas which are packed with particles probably correspond to closely appressed thylakoid regions or adhesive …

The compound internal pyrenoid in cultured cells of the green algaMonoraphidium griffithii (Berkel.) Komar.-Legner.

1979

The chloroplast ultrastructure ofMonoraphidium griffithii (Berkel.) Komar.-Legner. has been studied in axenic cultures of various ages. The algae have grown in a complete nutrient solution (illumination about 3,000 lx) and on its agar medium (illumination about 600 lx). The large parietal cup-shaped chloroplast of the cells includes a multiformed compound internal pyrenoid that is situated, especially in older cells, in the central part of the chloroplast opposite to the dictyosome and the nucleus. The chloroplast thylakoids either reach the edge of the pyrenoid or penetrate its matrix and run there parallel in more or less long bits. Starch grains were not found to form any sheath around t…

Chloroplastic glutamine synthetase from Brassica napus.

1993

Carotenoids

2009

Publisher Summary This chapter provides an overview of what is known about carotenoid metabolism in Chlamydomonas with reference to other green algae and vascular plants. The biosynthesis of carotenoids and the subdivisions of carotenogenesis are described. With respect to subcellular distribution, the carotenoids in vegetative cells localize to the chloroplast where they either serve as photosynthetic pigments bound to the protein complexes of the two photosystems, or as components of the eyespot apparatus is outlined with its functional significance. Carotenoids can serve as precursors of a number of other molecules with important physiological functions in Chlamydomonas.

Chapter 16 Folding and Pigment Binding of Light-Harvesting Chlorophyll a/b Protein (LHCIIb)

2010

The major light-harvesting chlorophyll a/b protein (LHCIIb) is one of the most abundant proteins of the chloroplast in green plants. It contains roughly half of the chlorophylls involved in photosynthesis, and exhibits an unusual ability to self-organize in vitro. Simply mixing the apoprotein, native or recombinant, with its pigments, chlorophyll a, chlorophyll b, and xanthophylls, in detergent solution, suffices to trigger protein folding and the assembly of about 18 pigments in their correct binding sites. A study of the mechanism of this self-organization seems worthwhile since (1) our knowledge about membrane protein folding is scarce compared to what we know about the folding of water-…

Studies on the Mechanism of Inhibition by Phosphinothricin of Glutamine Synthetase Isolated from Triticum aestivum L.

1986

Summary The activity of glutamine synthetase (EC 6.3.1.2) isolated from roots and leaves of wheat is strongly inhibited by phosphinothricin. As revealed by gel filtration and kinetic studies the mechanism of inhibition appears to be irreversible. The results indicate that the rate limiting step of the reaction of the inhibitor with the chloroplast glutamine synthetase is not the initial, but the following reaction. However, of root glutamine synthetase the irreversible inhibition follows a second order reaction depending on the concentration of the enzyme and of phosphinothricin and the rate limiting step is the formation of the initial enzyme-inhibitor complex. According to the kinetic dat…

Phylogenetic and biogeographical inferences for Pancratium (Amaryllidaceae), with an emphasis on the Mediterranean species based on plastid sequence …

2012

The phylogenetics and biogeography of Pancratium (Amaryllidaceae) were investigated, with a focus on the Mediterranean and adjacent areas, with the aim of contributing new information towards a better understanding of the evolutionary history of the genus and the taxonomic placement of P. linosae and P. hirtum. To address these questions, we sequenced four plastid DNA markers: the ndhF and rbcL genes, the trnL(UAA)-trnF(GAA) intergenic spacer and the trnL(UAA) intron, analysing them using parsimony, likelihood and Bayesian approaches. The results show that the relationships among the majority of the species are resolved; however, the relationships of one of the major clades of the genus are…

Involvement of Lipoxygenase-dependent Production of Fatty Acid Hydroperoxides in the Development of the Hypersensitive Cell Death induced by Cryptoge…

1999

Lipid peroxidation was investigated in relation with the hypersensitive reaction in cryptogein-elicited tobacco leaves. A massive production of free polyunsaturated fatty acid (PUFA) hydroperoxides dependent on a 9-lipoxygenase (LOX) activity was characterized during the development of leaf necrosis. The process occurred after a lag phase of 12 h, was accompanied by the concomitant increase of 9-LOX activity, and preceded by a transient accumulation of LOX transcripts. Free radical-mediated lipid peroxidation represented 10% of the process. Inhibition and activation of the LOX pathway was shown to inhibit or to activate cell death, and evidence was provided that fatty acid hydroperoxides ar…