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  • 1
    ISSN: 0014-5793
    Keywords: (Barley) ; 16 kDa polypeptide ; Photosystem I ; Transit peptide ; cDNA sequence
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1617-4623
    Keywords: Chlorophyll synthesis ; Coprogenoxidase ; Mg-protoporphyrin-monomethyl transferase ; Protoporphyrin IX ; xantha mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Barley mutants in the lociXantha-f, Xantha-g andXantha-h, when fed with 5-aminolevulinate in the dark, accumulate protoporphyrin IX. Mutant alleles at these loci that are completely blocked in protochlorophyllide synthesis are also blocked in development of prolamellar bodies in etioplasts. In contrast to wild type, thexan-f, -g and-h mutants had no detectable Mg-chelatase activity, whereas they all had methyltransferase activity for synthesis of Mg-protoporphyrin monomethyl ester. Antibodies recognising the CH42 protein ofArabidopsis thaliana and the OLIVE (OLI) protein ofAntirrhinum majus immunoreacted in wild-type barley with 42 and 150 kDa proteins, respectively. Thexan-h mutants lacked the protein reacting with antibodies raised against the CH42 protein. Twoxan-f mutants lacked the 150 kDa protein recognised by the anti-OLI antibody. Barley genes homologous to theA. majus olive and theA. thaliana Ch-42 genes were cloned using PCR and screening of cDNA and genomic libraries. Probes for these genes were applied to Northern blots of RNA from thexantha mutants and confirmed the results of the Western analysis. The mutantsxan-f 27, -f40, -h56 and-h 57 are defective in transcript accumulation while-h 38 is defective in translation. Southern blot analysis established thath 38 has a deletion of part of the gene. Mutantsxan-f 10 and-f 41 produce both transcript and protein and it is suggested that these mutations are in the catalytic sites of the protein. It is concluded thatXan-f and-h genes encode two subunits of the barley Mg-chelatase and thatXan-g is likely to encode a third subunit. The XAN-F protein displays 82% amino acid sequence identity to the OLI protein ofAntirrhinum, 66% to theSynechocystis homologue and 34% identity to theRhodobacter BchH subunit of Mg-chelatase. The XAN-H protein has 85% amino acid sequence identity to theArabidopsis CH42 protein, 69% identity to theEuglena CCS protein, 70% identity to theCryptomonas BchA andOlisthodiscus CssA proteins, as well as 49% identity to theRhodobacter BchI subunit of Mg-chelatase. Identification of the barleyXan-f andXan-h encoded proteins as subunits required for Mg-chelatase activity supports the notion that theAntirrhinum OLI protein and theArabidopsis CH42 protein are subunits of Mg-chelatase in these plants. The expression of both theXan-f and-h genes in wild-type barley is light induced in leaves of greening seedlings, and in green tissue the genes are under the control of a circadian clock.
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  • 3
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Protochlorophyll(ide) holochrome was isolated from dark-grown barley (Hordeum vulgare L.) leaves and photoconverted. When the chlorophyll(ide) absorption maximum had decreased from 680 to 676 nm the preparation was chromatographed on a Sephadex-gel column under conditions which strongly inhibited a further decrease in the absorption maximum. The absorption properties of the column fractions and the shape of the chlorophyll(ide) elution-profile indicated the presence of two distinct chlorophyll(ide)-bearing molecular species with apparent molecular weights of c. 74,000 and 29,000 and absorption maxima at 680 and 672 nm, respectively. It is concluded that: (1) no long-lived species with intermediate absorption maximum is formed during the 680 to 672 nm shift of the absorption maximum of newly photoconverted holochrome; (2) no long-lived pigment-protein complexes with intermediate molecular weights are formed during the approximate halving of the molecular weight; (3) the shift in the absorption maximum and the decrease in molecular weight are closely correlated.
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  • 4
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Rooting ability was studied for cuttings derived from stock plants of wild type pea seedlings and seedings of two mutants deficient in photosystem II activity and chlorophyll. Stock plants were grown at 15, 20, 25 or 30°C at 38 W m-2. Cuttings were rooted at 20°C and at an irradiance of 16 or 38 W m-2. The rooting ability seemed to be correlated with the initial carbohydrate content only at 38 W m-2. Based on the findings of the present study it may be concluded that for pea seedlings the growth temperature is more important than photosynthesis as regards accumulation of extractable carbohydrates. During the rooting period carbohydrates are necessary for root formation, but the effect of the iradiance on the number of roots formed is not mediated by the carbohydrate content. Under specific rooting conditions it is possible to correlate the initial carbohydrate content with the rooting capacity of the cuttings within a phenotype, but not always when different phenotypes are considered. The results indicate a connection between the metabolic activity of the cuttings and their ability to form adventitious roots.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 49 (1980), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Two nuclear gene mutants of pea, chlorotica-887 and chlorina-5756, are temperature-sensitive in the development of photosystem II activity. Low temperature flourescence emission spectra of leaves show that the peak at 697 nm from the reaction center of photosystem II is present when the mutants have been grown at 18°C, but absent when they have been grown at 30°C. For leaves of chlorina-5756 grown at 18°C the relative size of the peak at 697 nm is reduced compared to that of leaves of the wild type or chlorotica-887 grown at this temperature. Flourescence induction curves of leaves from wild type plants and chlorotica-887 grown at 18°C possess two steps, while those of leaves from chlorina-5756 grown at 18°C or 30°C and chlorotica-887 grown at 30°C show at fast rise to the maximal level of fluorescence. Measurements on chloroplasts isolated from the mutants indicated that the photosystem I activity per g leaf material is comparable for plants grown at 18°C and plants grown at 30°C. In contrast, no photosystem II activity was detected when the mutants had been grown at 30°C. It is suggested that these mutants are affected in a component required for the assembly of functional photosystem II complexes.
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 76 (1989), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The nucleotide sequence of a 5.7 kbp region of pea (Pisum sativum L.) chloroplast DNA containing the psbB operon and a putative promotor and termination site has been determined and compared to the corresponding sequences from spinach, maize, tobacco and the liverwort Marchantia polymorpha. The organization of the operon is the same as for the other species, i.e. psbB/psbH/petB/petD. These genes code for a 56 kDa chlorophyll-binding photosystem 2 (PS2) polypeptide, an 8 kDa PS2 polypeptide, cytochrome b6 (24 kDa) and subunit 4 (18 kDa) of the cytochrome b6/f complex. Two short and oppositely directed putative polypeptide genes are located between psbB and psbH. The petB and petD genes contain introns of 818 and 715 bp, respectively. The psbB, petB and petD proteins encoded in the pea operon are 89–98% homologous to those from the other species, while the pea psbH protein has a homology of 65–96% to that of the other species. The nucleotide sequences of introns and intergenic regions from the higher plants are 60–70% homologous. From comparisons with spinach sequences we conclude that the primary pea transcript probably has a length of 5603 bases.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 43 (1978), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Earlier work has shown that protochlorophyll(ide) holochrome is associated with the prolamellar body membranes in etioplasts of barley (Hordeum vulgare L.), and that this pigment-protein complex can be extracted in a stable, photoactive form by the use of saponin. For future work it would be advantageous if saponin, a detergent mixture, could be replaced by a single, well-characterized substance. The spectral characteristics of holochrome extracted with 10 ionic and nonionic detergents were compared to those of the holochrome extracted with saponin. Mulgofen BC-840 and digitonin extracted significant amounts of photoactive protochlorophyll(ide) holochrome, but this activity was highly labile, and no adequate substitute for saponin was found. Thus the stabilizing and solubilizing function of saponin is not simply related to the general properties of detergents.
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  • 8
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The nucleotide sequence of an 8 kbp region of pea (Pisum sativum L.) chloroplast DNA containing the rRNA operon and putative promoter sites has been determined and compared to the corresponding sequences from maize, tobacco and the liverwort Marchantia polymorpha. The chloroplast DNA species of all vascular plants investigated, with the exception of a few legumes including pea, and of Marchantia contain an inverted repeat with an rRNA operon. The pea rRNA operon is the first sequenced rRNA operon from a plant with only one copy of the rRNA genes per molecule of chloroplast DNA. The organization of the operon is the same as for maize, tobacco and Marchantia. i.e. tRNA-Val gene/16S rRNA gene/spacer with intron-containing genes for tRNA-Ile and tRNA-Ala/23S rRNA gene/4.5S rRNA gene/5S rRNA gene. Current evidence suggests that the tRNA-Val gene may not be contranscribed with the other genes. For pea 16S, 23S, 4.5S and 5S rRNA have 1488, 2813, 105 and 121 nucleotides, respectively. The homologies of the entire operon (the tRNA-Val gene - 5S rRNA region) to those from tobacco, maize and Marchantia are 88, 82 and 79%, respectively. The corresponding homologies for tobacco/maize, tobacco/Marchantia and maize/Marchantia have similar values. The 16S and 23S rRNA genes from pea are more than 90% homologous to those from the 3 other species. We conclude that the fact that pea only has one set of rRNA genes per molecule of chloroplast DNA is apparently not correlated with any significant difference between the pea operon and the rRNA operons from tobacco, maize and Marchantia.
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  • 9
    ISSN: 1432-203X
    Keywords: Keywords Abscisic acid ; Ethylene ; ETR homologues ; Flower senescence ; Rosa hybrida ; Abbreviations ABA Abscisic acid ; DIG Digoxigenin ; SSC Standard saline citrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  To analyze differences in flower longevity and ethylene sensitivity, we isolated Rosa hybrida gene fragments with sequence similarity to the Arabidopsis thaliana ethylene receptor gene-family. A rose gene (RhETR1) highly similar to AtERS1 had been previously sequenced. Here, we report the isolation of three additional partial rose genes (RhETR2–4) belonging to different sub-groups of ethylene receptor genes. RhETR2 clusters with AtETR1, RhETR4 with AtERS1 and RhETR1, whereas RhETR3 shows high sequence similarity to AtETR2 and AtERS2. Expression analysis of RhETR2 and RhETR3 revealed that they are differentially expressed. RhETR2 is expressed at a constitutive level throughout flower development whereas RhETR3 expression increases in senescing flowers of the cultivar Bronze which has a short floral life while it remains at low levels in the long-lasting flowers of the cultivar Vanilla. Expression of both genes was increased by ABA and ethylene treatment, but transcript abundance differed between rose cultivars with different postharvest performance. These results indicate that differences in flower life among rose cultivars could be due to differences in receptor levels.
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  • 10
    ISSN: 1573-5028
    Keywords: chlorophyll a-binding protein ; chloroplast DNA ; nucleotide sequence ; photosystem I gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The genes encoding the two P700 chlorophyll a-apoproteins of the photosystem I complex were localized on the pea (Pisum sativum) chloroplast genome. The nucleotide sequence of the genes and the flanking regions has been determined. The genes are separated by 25 bp and are probably cotranscribed. The 5′ terminal gene (psaA1) codes for a 761-residue protein (MW 84.1 kD) and the 3′ terminal gene (psaA2) for a 734-residue protein (MW 82.4 kD). Both proteins are highly hydrophobic and contain eleven putative membrane-spanning domains. The homology to the corresponding polypeptides from maize are 89% and 95% for psaA1 and psaA2, respectively. A putative promoter has been identified for the psaA1 gene, and potential ribosome binding sites are present before both genes.
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