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  • 1. Andersson, Anders
    et al.
    Keskitalo, Johanna
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Sjödin, Andreas
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Bhalerao, Rupali
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Sterky, Fredrik
    Wissel, Kirsten
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Tandre, Karolina
    Aspeborg, Henrik
    Moyle, Richard
    Ohmiya, Yasunori
    Bhalerao, Rishikesh
    Brunner, Amy
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Lundeberg, Joakim
    Nilsson, Ove
    Sandberg, Göran
    Strauss, Steven
    Sundberg, Björn
    Uhlen, Mathias
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nilsson, Peter
    A transcriptional timetable of autumn senescence2004In: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 5, no 4, p. R24-Article in journal (Refereed)
    Abstract [en]

    Background We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. Results On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. Conclusions We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components.

  • 2. Barker-Åström, Kara
    et al.
    Schelin, Jenny
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Clarke, Adrian K
    Campbell, Douglas A
    Chlorosis during nitrogen starvation is altered by carbon dioxide and temperature status and is mediated by the ClpP1 protease in Synechococcus elongatus.2005In: Archives of Microbiology, ISSN 0302-8933, Vol. 183, no 1, p. 66-9Article in journal (Refereed)
    Abstract [en]

    The interactive effects of inorganic carbon status, temperature and light on chlorosis induced by nitrogen deficiency, and the roles of Clp proteases in this process were investigated. In wild-type cultures grown in high or ambient CO2, following transfer to media lacking combined nitrogen, phycocyanin per cell dropped primarily through dilution of the pigment through cell division, and also suffered variable degrees of net degradation. When grown at high CO2 (5%), chlorophyll (Chl) suffered net degradation to a greater extent than phycocyanin. In marked contrast, growth at ambient CO2 resulted in Chl per cell dropping through dilution. Conditions that drove net Chl degradation in the wild-type resulted in little or no net Chl degradation in a clpPI inactivation mutant, with Chl content dropping largely through growth dilution in the mutant. The chlorotic response of a clpPII inactivation strain was nearly the same as that of wild-type, although phycocyanin degradation may have been slightly accelerated in the former.

  • 3. Bhalerao, RP
    et al.
    Collier, JL
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Grossman, AR
    The structure of phycobilisomes in mutants of synechococcus sp strain pcc-7942 devoid of specific linker polypeptides1995In: Photochemistry and Photobiology, ISSN 0031-8655, E-ISSN 1751-1097, Vol. 61, no 3, p. 298-302Article in journal (Refereed)
    Abstract [en]

    The effect of elimination of the 30, 33 and 9 kDa phycobilisome rod-linker polypeptides on rod length was examined by electron microscopy of phycobilisomes isolated from wild-type Synechococcus sp. strain PCC 7942 and from genetically engineered mutants with lesions in the genes encoding the rod-linker polypeptides. The maximum rod length in the absence of the 33 kDa linker polypeptide was two phycocyanin hexamers, whereas rods with up to five hexamers were found in the mutant strain lacking the 30 kDa linker polypeptide. Elimination of the 9 kDa linker polypeptide did not have a significant effect on rod length. Finally, mutants lacking either the 30 or 33 kDa rod-associated linker polypeptides had an increased number of rods that terminated with a phycocyanin trimer. These observations are discussed with respect to the role of the linker polypeptides in the biosynthesis of the rod substructure.

  • 4. Bhalerao, RP
    et al.
    Gillbro, T
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Structure and energy-transfer of the phycobilisome in a linker protein replacement mutant of cyanobacterium synechococcus-79421991In: Biochimica et Biophysica Acta, ISSN 0006-3002, E-ISSN 1878-2434, Vol. 1060, no 1, p. 59-66Article in journal (Refereed)
    Abstract [en]

    The role of the linker proteins in the biogenesis and energy transfer of the phycobilisome rod was monitored by making insertional inactivation in the cpcI gene coding for the core-proximal 33 kilodalton (kDa) protein in the cyanobacterium Synechococcus 7942. The insertion leaves the cpcH gene coding for the core-distal 30 kDa protein intact and functional. Analysis of the phycobilisome protein composition of the cpcI mutant shows that the 30 kDa protein is present in normal amounts in the rod, indicating that the 30 kDa linker protein can replace the 33 kDa protein in the biogenesis and structural integrity of the rod. The absorption and fluorescence characteristics of the mutated phycobilisome is almost indistinguishable from that of the wild-type of the same rod length. The fluorescence kinetics from the cpcI mutant show that the dominating decay component has a lifetime from phycocyanin of 69 ps as compared to 72 ps found for the wild-type phycobilisome with the same rod length. The results show that replacing the 33 kDa for the 30 kDa linker in the rod does not alter the energy harvesting or the energy transfer characteristics of the rod in contrast to what has been concluded from data obtained from in vitro experiments. We conclude that the linker polypeptides have only a minor influence on the energy transfer characteristics of the rod but are mainly involved in determining the length of the rod in response to changing environmental light conditions.

  • 5. Bhalerao, RP
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Factors influencing the phycobilisome rod composition of the cyanobacterium synechococcus sp pcc-7942: effects of reduced phycocyanin content, lack of rod-linkers, and over-expression of the rod-terminating linker1994In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 90, no 1, p. 187-197Article in journal (Refereed)
    Abstract [en]

    Four novel mutants with altered phycobilisomes were constructed in the cyanobacterium Synechococcus 7942 to study factors influencing the rod length and composition. These mutants show (1) reduced phycocyanin content, (2) reduced phycocyanin content combined with loss of the 33 kDa linker, (3) loss of the 30 kDa rod-linker and (4) overexpression of the 9 kDa rod terminating linker. For these mutants we determined the 33 to 27 kDa and 30 to 27 kDa linker ratios in the isolated phycobilisomes and compared these ratios with those in the wild type. The 30 kDa linker can be incorporated into the rods in absence of the 33 kDa linker. The incorporation of the 30 kDa linker is lower in absence of the 33 kDa linker. When the 30 kDa linker is missing, an increase in the level of the 33 kDa linker is seen, indicating that there could be an excess of the 33 kDa linker in the cells. Our results also show that a reduction in the phycocyanin content causes a decrease in the rod length simultaneously with a reduction of the 30/27 linker ratio, without altering the 33/27 ratio. Reduced phycocyanin content and absence of the 33 kDa linker cause a dramatic reduction in the incorporation of the 30 kDa linker into the rods in the mutant B2SMIKM. Over-expression of the 9 kDa linker results in a decreased incorporation of both the 33 and 30 kDa linkers into the rods, the effect being more pronounced for the 30 kDa linker. This result indicates that the level of the 9 kDa linker relative to those of the 33 and the 30 kDa linkers may be an important determinant of the phycobilisome rod length.

  • 6. Bhalerao, RP
    et al.
    Lind, LK
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Cloning of the cpce and cpcf genes from synechococcus sp pcc-6301 and their inactivation in synechococcus sp pcc-79421994In: Plant Molecular Biology, ISSN 0167-4412, E-ISSN 1573-5028, Vol. 26, no 1, p. 313-326Article in journal (Refereed)
    Abstract [en]

    Two open reading frames denoted as cpcE and cpcF were cloned and sequenced from Synechococcus sp. PCC 6301. The cpcE and cpcF genes are located downstream of the cpcB2A2 gene cluster in the phycobilisome rod operon and can be transcribed independently of the upstream cpcB2A2 gene cluster. The cpcE and cpcF genes were separately inactivated by insertion of a kanamycin resistance cassette in Synechococcus sp. PCC 7942 to generate mutants R2EKM and R2FKM, respectively, both of which display a substantial reduction in spectroscopically detectable phycocyanin. The levels of beta- and alpha-phycocyanin polypeptides were reduced in the R2EKM and R2FKM mutants although the phycocyanin and linker genes are transcribed at normal levels in the mutants as in the wild type indicating the requirement of the functional cpcE and cpcF genes for normal accumulation of phycocyanin. Two biliprotein fractions were isolated on sucrose density gradient from the R2EKM/R2FKM mutants. The faster sedimenting fraction consisted of intact phycobilisomes. The slower sedimenting biliprotein fraction was found to lack phycocyanin polypeptides, thus no free phycocyanin was detected in the mutants. Characterization of the phycocyanin from the mutants revealed that it was chromophorylated, had a lambda(max) similar to that from the wild type and could be assembled into the phycobilisome rods. Thus, although phycocyanin levels are reduced in the R2EKM and R2FKM mutants, the remaining phycocyanin seems to be chromophorylated and similar to that in the wild type with respect to phycobilisome rod assembly and energy transfer to the core.

  • 7. Bhalerao, RP
    et al.
    Lind, LK
    Persson, CE
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Cloning of the phycobilisome rod linker genes from the cyanobacterium synechococcus sp pcc-6301 och their inactivation in synechococcus sp pcc-79421993In: Molecular General Genetics, ISSN 0026-8925, E-ISSN 1432-1874, Vol. 237, no 1-2, p. 89-96Article in journal (Refereed)
    Abstract [en]

    The phycobilisome rod linker genes in the two closely related cyanobacteria Synechococcus sp. PCC 6301 and Synechococcus sp. PCC 7942 were studied. Southern blot analysis showed that the genetic organization of the phycobilisome rod operon is very similar in the two strains. The phycocyanin gene pair is duplicated and separated by a region of about 2.5 kb. The intervening region between the duplicated phycocyanin gene pair was cloned from Synechococcus sp. PCC 6301 and sequenced. Analysis of this DNA sequence revealed the presence of three open reading frames corresponding to 273, 289 and 81 amino acids, respectively. Insertion of a kanamycin resistance cassette into these open reading frames indicated that they corresponded to the genes encoding the 30, 33 and 9 kDa rod linkers, respectively, as judged by the loss of specific linkers from the phycobilisomes of the insertional mutants. Amino acid compositions of the 30 and 33 kDa linkers derived from the DNA sequence were found to deviate from those of purified 33 and 30 kDa linkers in the amounts of glutamic acid/glutamine residues. On the basis of similarity of the amino acid sequence of the rod linkers between Synechococcus sp. PCC 6301 and Calothrix sp. PCC 7601 we name the genes encoding the 30, 33 and 9 kDa linkers cpcH, cpcI and cpcD, respectively. The three linker genes were found to be co-transcribed on an mRNA of 3700 nucleotides. However, we also detected a smaller species of mRNA, of 3400 nucleotides, which would encode only the cpcH and cpcI genes. The 30 kDa linker was still found in phycobilisome rods lacking the 33 kDa linker and the 9 kDa linker was detected in mutants lacking the 33 or the 30 kDa linkers. Free phycocyanin was found in the mutants lacking the 33 or the 30 kDa linkers, whereas no free phycocyanin could be found in the mutant lacking the 9 kDa linker.

  • 8.
    Bhalerao, Rupali
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Keskitalo, Johanna
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sterky, Fredrik
    Erlandsson, Rikard
    Björkbacka, Harry
    Birve, Simon Jonsson
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gardeström, Per
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Lundeberg, Joakim
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gene expression in autumn leaves2003In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 131, no 2, p. 430-442Article in journal (Refereed)
    Abstract [en]

    Two cDNA libraries were prepared, one from leaves of a field-grown aspen (Populus tremula) tree, harvested just before any visible sign of leaf senescence in the autumn, and one from young but fully expanded leaves of greenhouse-grown aspen (Populus tremula x tremuloides). Expressed sequence tags (ESTs; 5,128 and 4,841, respectively) were obtained from the two libraries. A semiautomatic method of annotation and functional classification of the ESTs, according to a modified Munich Institute of Protein Sequences classification scheme, was developed, utilizing information from three different databases. The patterns of gene expression in the two libraries were strikingly different. In the autumn leaf library, ESTs encoding metallothionein, early light-inducible proteins, and cysteine proteases were most abundant. Clones encoding other proteases and proteins involved in respiration and breakdown of lipids and pigments, as well as stress-related genes, were also well represented. We identified homologs to many known senescence-associated genes, as well as seven different genes encoding cysteine proteases, two encoding aspartic proteases, five encoding metallothioneins, and 35 additional genes that were up-regulated in autumn leaves. We also indirectly estimated the rate of plastid protein synthesis in the autumn leaves to be less that 10% of that in young leaves.

  • 9.
    Bylesjö, Max
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Segura, Vincent
    Soolanayakanahally, Raju Y
    Rae, Anne M
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Street, Nathaniel R
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LAMINA: a tool for rapid quantification of leaf size and shape parameters2008In: BMC Plant Biology, ISSN 1471-2229, Vol. 8, no 82, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Background

    An increased understanding of leaf area development is important in a number of fields: in food and non-food crops, for example short rotation forestry as a biofuels feedstock, leaf area is intricately linked to biomass productivity; in paleontology leaf shape characteristics are used to reconstruct paleoclimate history. Such fields require measurement of large collections of leaves, with resulting conclusions being highly influenced by the accuracy of the phenotypic measurement process.

    Results

    We have developed LAMINA (Leaf shApe deterMINAtion), a new tool for the automated analysis of images of leaves. LAMINA has been designed to provide classical indicators of leaf shape (blade dimensions) and size (area), which are typically required for correlation analysis to biomass productivity, as well as measures that indicate asymmetry in leaf shape, leaf serration traits, and measures of herbivory damage (missing leaf area). In order to allow Principal Component Analysis (PCA) to be performed, the location of a chosen number of equally spaced boundary coordinates can optionally be returned.

    Conclusion

    We demonstrate the use of the software on a set of 500 scanned images, each containing multiple leaves, collected from a common garden experiment containing 116 clones of Populus tremula (European trembling aspen) that are being used for association mapping, as well as examples of leaves from other species. We show that the software provides an efficient and accurate means of analysing leaf area in large datasets in an automated or semi-automated work flow.

  • 10. Campbell, D
    et al.
    Bruce, D
    Carpenter, C
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Two forms of the photosystem II D1 protein alter energy dissipation and state transitions in the cyanobacterium Synechococcus sp PCC 79421996In: Photosynthesis Research, ISSN 0166-8595, E-ISSN 1573-5079, Vol. 47, no 2, p. 131-144Article in journal (Refereed)
    Abstract [en]

    Synechococcus sp. PCC 7942 (Anacystis nidulans R2) contains two forms of the Photosystem II reaction centre protein D1, which differ in 25 of 360 amino acids. D1:1 predominates under low light hut is transiently replaced by D1:2 upon shifts to higher light. Mutant cells containing only D1:1 have lower photochemical energy capture efficiency and decreased resistance to photoinhibition, compared to cells containing D1:2. We show that when dark-adapted or under low to moderate light, cells with D1:1 have higher non-photochemical quenching of PS II fluorescence (higher q(N)) than do cells with D1:2. This is reflected in the 77 K chlorophyll emission spectra, with lower Photosystem II fluorescence at 697-698 nm in cells containing D1:1 than in cells with D1:2. This difference in quenching of Photosystem II fluorescence occurs upon excitation of both chlorophyll at 435 nm and phycobilisomes at 570 nm. Measurement of time-resolved room temperature fluorescence shows that Photosystem II fluorescence related to charge stabilization is quenched more rapidly in cells containing D1:1 than in those with D1:2. Cells containing D1:1 appear generally shifted towards State II, with PS II down-regulated, while cells with D1:2 tend towards State I. In these cyanobacteria electron transport away from PS II remains non-saturated even under photoinhibitory levels of light. Therefore, the higher activity of D1:2 Photosystem II centres may allow more rapid photochemical dissipation of excess energy into the electron transport chain. D1:1 confers capacity for extreme State II which may be of benefit under low and variable light.

  • 11. Campbell, D
    et al.
    Clarke, A K
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oxygen-dependent electron flow influences photosystem II function and psbA gene expression in the cyanobacterium Synechococcus sp PCC 79421999In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 105, no 4, p. 746-755Article in journal (Refereed)
    Abstract [en]

    During acclimated growth in Synechococcus sp, PCC 7942 a substantial proportion of the electrons extracted from mater by photosystem II ultimately flow back to oxygen, This flow increases rapidly under high light, which allows Synechococcus to maintain photosystem II centers largely open, even under excessive excitation, The electron flow to oxygen with increasing light accounts for the progressive discrepancy between the light response curve of measured oxygen evolution, and the light response curve of photosystem II activity estimated from fluorescence measures. In cells under anoxia this flexible electron sink is lost and photosystem II centers suffer partial closure at the growth light intensity, with closure becoming more severe under excess light. As predicted from earlier work this PSII closure results in rapid loss of psbAI message, encoding the D1:1 protein of PSII, and induction of psbAII/AIII encoding the alternate D1:2 protein. The changes in the mRNA pool are not, however, reflected at the protein level, and D1:1 remains in the thylakoid membranes. There is no accumulation of D1:2, despite some continued synthesis of other proteins. PSII closure, therefore, results in repression of psbAI and induction psbAII/AIII expression, but D1:1/D1:2 exchange is blocked by anoxia, downstream from transcription. D1:1 protein and PSII activity are quite stable under anoxia and moderate illumination, Nevertheless, upon recovery under oxygenic conditions, the existing D1:1 is lost from the membranes, resulting in a transient drop in PSII activity. This suggests that under normal conditions the cells use oxygen to facilitate preemptive turnover of D1 proteins.

  • 12. Campbell, D
    et al.
    Eriksson, Mats-Jerry
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Clarke, A K
    A cyanobacterium resists UV-B by exchanging Photosystem II D1 proteins.1997In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 114, no 3, p. 30004-30004Article in journal (Refereed)
  • 13. Campbell, D
    et al.
    Eriksson, Mats-Jerry
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Clarke, A K
    The cyanobacterium Synechococcus resists UV-B by exchanging photosystem II reaction-center D1 proteins1998In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 95, no 1, p. 364-369Article in journal (Refereed)
    Abstract [en]

    Current ambient UV-B levels can significantly depress productivity in aquatic habitats, largely because UV-B inhibits several steps of photosynthesis, including the photooxidation of water catalyzed by photosystem II, We show that upon UV-B exposure the cyanobacterium Synechococcus sp, PCC 7942 rapidly changes the expression of a family of three psbA genes encoding photosystem II D1 proteins, In wild-type cells the psbAI gene is expressed constitutively, but strong accumulations of psbAII and psbAIII transcripts are induced within 15 min of moderate UV-B exposure (0.4 W/m(2)), This transcriptional response causes an exchange of two distinct photosystem II D1 proteins, D1:1 is encoded by psbAI, but on UV-B exposure, it is largely replaced by the alternate D1:2 form, encoded by both psbAII and psbAIII, The total content of D1 and other photosystem II reaction center protein, D2, remained unchanged throughout the UV exposure, as did the content and composition of the phycobilisome, Wild-type cells suffered only slight transient inhibition of photosystem II function under UV-B exposure, In marked contrast, under the same UV-B treatment, a mutant strain expressing only psbAI suffered severe (40%) and sustained inhibition of photosystem II function, Another mutant strain with constitutive expression of psbAII and psbAIII was almost completely resistant to the UV-B treatment, showing no inhibition of photosystem II function and only a slight drop in electron transport, In Synechococcus the rapid exchange of alternate D1 forms, therefore, accounts for much of the cellular resistance to UV-B inhibition of photosystem II activity and photosynthetic electron transport, This molecular plasticity may be an important element in community-level responses to UV-B, where susceptibility to UV-B inhibition of photosynthesis changes diurnally.

  • 14. Campbell, D
    et al.
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Clarke, A K
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Chlorophyll fluorescence analysis of cyanobacterial photosynthesis and acclimation1998In: Microbiology and molecular biology reviews, ISSN 1092-2172, E-ISSN 1098-5557, Vol. 62, no 3, p. 667-+Article, review/survey (Refereed)
    Abstract [en]

    Cyanobacteria are ecologically important photosynthetic prokaryotes that also serve as popular model organisms for studies of photosynthesis and gene regulation. Both molecular and ecological studies of cyanobacteria benefit from real-time information on photosynthesis and acclimation. Monitoring in vivo chlorophyll fluorescence can provide noninvasive measures of photosynthetic physiology in a wide range of cyanobacteria and cyanolichens and requires only small samples. Cyanobacterial fluorescence patterns are distinct from those of plants, because of key structural and functional properties of cyanobacteria. These include significant fluorescence emission from the light-harvesting phycobiliproteins; large and rapid changes in fluorescence yield (state transitions) which depend on metabolic and environmental conditions; and flexible, overlapping respiratory and photosynthetic electron transport chains. The fluorescence parameters F-V/F-M. F-V'/F-M', q(p),q(N), NPQ, and phi PS II were originally developed to extract information from the fluorescence signals of higher plants. In this review, we consider how the special properties of cyanobacteria can be accommodated and used to extract biologically useful information from cyanobacterial in vivo chlorophyll fluorescence signals. We describe how the pattern of fluorescence yield versus light intensity can be used to predict the acclimated light level for a cyanobacterial population, giving information valuable for both laboratory and field studies of acclimation processes. The size of the change in fluorescence yield during dark-to-light transitions can provide information on respiration and the iron status of the cyanobacteria. Finally, fluorescence parameters cart be used to estimate the electron transport rate at the acclimated growth light intensity.

  • 15. CAMPBELL, D
    et al.
    ZHOU, GQ
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    CLARKE, AK
    ELECTRON-TRANSPORT REGULATES EXCHANGE OF 2 FORMS OF PHOTOSYSTEM-II D1 PROTEIN IN THE CYANOBACTERIUM SYNECHOCOCCUS1995In: EMBO Journal, ISSN 0261-4189, E-ISSN 1460-2075, Vol. 14, no 22, p. 5457-5466Article in journal (Refereed)
    Abstract [en]

    Synechococcus sp, PCC 7942 modulates photosynthetic function by transiently replacing the constitutive D1 photosystem II protein, D1:1, with an alternate form, D1:2, to help counteract photoinhibition under excess light, We show that a temperature drop from 37 to 25 degrees C also drives D1:1/D1:2 exchange under constant, moderate light, Chilling or light-induced D1 exchange results from rapid loss of psbAI message coding for D1:1 and accumulation of psbAII and psbAIII messages coding for D1:2, During chilling, a large pool of a novel form, D1:2*, transiently accumulates, distinguishable from normal D1 by an increase in apparent molecular mass, D1:* is not phosphorylated and is probably a functionally inactive, incompletely processed precursor, After acclimation to 25 degrees C, D1:2* disappears and D1:1 again predominates, although substantial D1:2 remains, Partial inhibition of electron transport under constant, moderate light also triggers the D1 exchange process, These treatments all increase excitation pressure on photosystem II relative to electron transport, Therefore, information from photosynthetic electron transport regulates D1 exchange without any requirement for a change in light intensity or quality, possibly via a redox sensing mechanism proximal to photosystem II.

  • 16. CLARKE, AK
    et al.
    CAMPBELL, D
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    DYNAMIC-RESPONSES OF PHOTOSYSTEM-II AND PHYCOBILISOMES TO CHANGING LIGHT IN THE CYANOBACTERIUM SYNECHOCOCCUS SP PCC-79421995In: Planta, ISSN 0032-0935, E-ISSN 1432-2048, Vol. 197, no 3, p. 553-562Article in journal (Refereed)
    Abstract [en]

    We have examined the molecular and photosynthetic responses of a planktonic cyanobacterium to shifts in light intensity over periods up to one generation (7 h). Synechococcus sp. PCC 7942 possesses two functionally distinct forms of the D1 protein, D1:1 and D1:2. Photosystem II (PSII) centers containing D1:1 are less efficient and more susceptible to photoinhibition than are centers containing D1:2, Under 50 mu mol photons m(-2). s(-1), PSII centers contain D1:1, but upon shifts to higher light (200 to 1000 mu mol photons m(-2). s(-1)), D1:1 is rapidly replaced by D1:2, with the rate of interchange dependent on the magnitude of the light shift. This interchange is readily reversed when cells are returned to 50 mu mol photons m(-2). s(-1). If, however, incubation under 200 mu mol photons m(-2). s(-1) is extended, D1:1 content recovers and by 3 h after the light shift D1:1 once again predominates. Oxygen evolution and chlorophyll (Chi) fluorescence measurements spanning the light shift and D1 interchanges showed an initial inhibition of photosynthesis at 200 mu mol photons m(-2). s(-1), which correlates with a proportional loss of total D1 protein and a cessation of growth. This was followed by recovery in photosynthesis and growth as the maximum level of D1:2 is reached after 2 h at 200 mu mol photons m(-2). s(-1) Thereafter, photosynthesis steadily declines with the loss of D1:2 and the return of the less-efficient D1:1. During the D1:1/D1:2 interchanges, no significant change occurs in the level of phycocyanin (PC) and Chl a, nor of the phycobilisome rod linkers. Nevertheless, the initial PC/Chl a ratio strongly influences the magnitude of photoinhibition and recovery during the light shifts. In Synechococcus sp. PCC 7942, the PC/Chl a ratio responds only slowly to light intensity or quality, while the rapid but transient interchange between D1:1 and D1:2 modulates PSII activity to limit damage upon exposure to excess light.

  • 17. CLARKE, AK
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LIDHOLM, JA
    IDENTIFICATION AND EXPRESSION OF THE CHLOROPLAST CLPP GENE IN THE CONIFER PINUS-CONTORTA1994In: Plant Molecular Biology, ISSN 0167-4412, E-ISSN 1573-5028, Vol. 26, no 3, p. 851-862Article in journal (Refereed)
    Abstract [en]

    The clpP gene from the conifer Pinus contorta was identified and isolated from a chloroplast genomic library by heterologous hybridisation to the second exon of the chloroplast clpP gene in tobacco. DNA sequencing of two overlapping clones revealed an uninterrupted 615 bp open-reading frame with 41 to 65% similarity to the clpP genes in five other chloroplast genomes and Escherichia coli. The 615 bp sequence in P. contorta contained perfectly matched motifs for the serine and histidine active sites of the GlpP protease in E. coli. The location of the clpP gene was determined using a physical map of the P. contorta chloroplast genome, and was found to lie within a 10 kb region between the psbE/F and vpoB genes. Sequencing of the regions adjacent to the clpP gene revealed the first exon of the rps12 gene located 135 bp downstream. The genomic position of the first exon of the rps12 gene in relation to the clpP gene is conserved for all other chloroplast clpP genes identified so far. Northern blot analysis showed that the clpP gene in both P. contorta and P. sylvestris was present in several transcript of different length, ranging from 0.8 to 2.4 kb. The two longer transcripts in P. contorta also included the first exon of the rps12 gene. Mapping of the 5' end of the clpP transcripts by primer extension, however, revealed a single transcription initiation site 53 bp upstream of the first ATG codon. Analysis of total RNA isolated from The two pine species grown in darkness or moderate light conditions (250 mu mol photons m(-2) s(-1)) showed no significant difference in the level of expression of the clpP gene. The results suggest that the clpP gene in conifers is part of an operon which includes the first exon of the rps12 and the entire rp120 gene, and is expressed in a light-independent manner as a polycistronic precursor which later undergoes post-transcriptional processing to give the mature monocistronic clpP mRNA.

  • 18. CLARKE, AK
    et al.
    HURRY, VM
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    2 FUNCTIONALLY DISTINCT FORMS OF THE PHOTOSYSTEM-II REACTION-CENTER PROTEIN D1 IN THE CYANOBACTERIUM SYNECHOCOCCUS SP PCC 79421993In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 90, no 24, p. 11985-11989Article in journal (Refereed)
    Abstract [en]

    The cyanobacterium Synechococcus sp. PCC 7942 possesses a small psbA multigene family that codes for two distinct forms of the photosystem II reaction-center protein D1 (D1:1 and D1:2). We showed previously that the normally predominant D1 form (D1:1) was rapidly replaced with the alternative D1:2 when cells adapted to a photon irradiance of 50 mumol/m-2.s-1 are shifted to 500 mumol.m-2.s-1 and that this interchange was readily reversible once cells were allowed to recover under the original growth conditions. By using the psbA inactivation mutants R2S2C3 and R2K1 (which synthesize only D1:1 and D1:2, respectively), we showed that this interchange between D1 forms was essential for limiting the degree of photoinhibition as well as enabling a rapid recovery of photosynthesis. In this report, we have extended these findings by examining whether any intrinsic functional differences exist between the two D1 forms that may afford increased resistance to photoinhibition. Initial studies on the rate of D1 degradation at three photon-irradiances (50, 200, and 500 mumol.m-2.s-1) showed that the rates of degradation for both D1 forms increase with increasing photon flux density but that there was no significant difference between D1:1 and D1:2. Analysis of light-response curves for oxygen evolution for the mutants R2S2C3 and R2K1 revealed that cells with photosystem II reaction centers containing D1:2 have a higher apparent quantum yield (almost-equal-to 25%) than cells possessing D1:1. Further studies using chlorophyll a fluorescence measurements confirmed that R2K1 has a higher photochemical yield than R2S2C3; that is, a more efficient conversion of excitation energy from photon absorption into photochemistry. We believe that the higher photochemical efficiency of reaction centers containing D1:2 is causally related to the preferential induction of D1:2 at high light and thus may be an integral component of the protection mechanism within Synechococcus sp. PCC 7942 against photoinhibition.

  • 19. CLARKE, AK
    et al.
    SOITAMO, A
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    RAPID INTERCHANGE BETWEEN 2 DISTINCT FORMS OF CYANOBACTERIAL PHOTOSYSTEM-II REACTION-CENTER PROTEIN-D1 IN RESPONSE TO PHOTOINHIBITION1993In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 90, no 21, p. 9973-9977Article in journal (Refereed)
    Abstract [en]

    We have studied photoinhibition of photosynthesis in the cyanobacterium Synechococcus sp. PCC 7942, which possesses two distinct forms of the photosystem II reaction-center protein D1 (D1:1 and D1:2). We report here that when cells adapted to a growth irradiance of 50 mumol.m-2.s-1 are exposed to an irradiance of 500 mumol.m-2.s-1, the normally predominant D1 form (D1:1) is rapidly replaced with the alternative D1:2. This interchange is not only complete within the first hour of photoinhibition but is also fully reversible once cells are returned to 50 mumol.m-2.s-1. By using a mutant that synthesizes only D1:1, we show that the failure to replace D1:1 with D1:2 during photoinhibition results in severe loss of photosynthetic activity as well as a diminished capacity to recover after the stress period. We believe that this interchange between D1 forms may constitute an active component in a protection mechanism unique among photosynthetic organisms that enables cyanobacteria to effectively cope with and recover from photoinhibition.

  • 20. GUSTAFSSON, L
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LOW GENETIC-VARIATION IN SWEDISH POPULATIONS OF THE RARE SPECIES VICIA-PISIFORMIS (FABACEAE) REVEALED WITH RFLP (RDNA) AND RAPD1994In: Plant Systematics and Evolution, ISSN 0378-2697, E-ISSN 1615-6110, Vol. 189, no 3-4, p. 133-148Article in journal (Refereed)
    Abstract [en]

    Nine Swedish populations, 1-5 individuals/population, and one cultivated individual of the rare species Vicia pisiformis were investigated for genetic variation. In hybridizations with two rDNA probes using 8 restriction enzymes, only two individuals belonging to one population were polymorphic. A map of the rDNA gene cluster was constructed for four of the restriction enzymes used. Two of the polymorphic sites were mapped and were found to be located outside regions coding for rRNA, presumably caused by single point mutations or small deletions. The repeat length of the rDNA region was c. 10,000 bp, which corresponds well with the size found for other species belonging to Fabaceae. No length polymorphism was found in the intergenic spacer, contrary to the situation found for most other plant species investigated for rDNA variation. The haplotype diversity for the species (Hsp Shannon) was very low (0.055). Within-population values (Hpop) was 0 for all populations except the variable one, which had 0.301. PCR amplification with 6 random primers also revealed very low levels of genetic diversity. A polymorphism was observed in a limited number of individuals for four populations. Hsp was 0.065 and HpopBAR was 0.050. The average D value (Wetton) for the PCR haplotypes was 0.99.

  • 21.
    Gustafsson, Petter
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LIDHOLM, J
    LUNDBERG, AK
    STRUCTURE AND REGULATION OF PHOTOSYNTHESIS GENES IN PINUS-SYLVESTRIS (SCOTS PINE) AND PINUS-CONTORTA (LODGEPOLE PINE)1991In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 43, no 3-4, p. 287-300Article in journal (Refereed)
    Abstract [en]

    The structure and regulation of one nuclear and one chloroplast gene was studied in Pinus sylvestris (Scots pine) and Pinus contorta (lodgepole pine). cDNA copies of the nuclear located cab genes of Pinus sylvestris, coding for the light-harvesting chlorophyll a/b-binding proteins of photosystem II (LHC-II), were cloned. cab-II genes coding for both types of LHC-II polypeptides, Types 1 and 2, were found. An analysis of the DNA sequences of several different cab-II cDNAs shows that they have a high bias for the nucleotides G and C at the third base positions of the codons, making them more similar to monocot than to dicot genes. Two of the three genes were found to be located within CpG islands. The cab-II genes were found to be expressed in dark-grown seedlings in contrast to what has been found for most angiosperms. The chloroplast genomes of conifers were shown to lack the inverted repeat organization normally found in higher plants, mosses and green algae. The psbA gene, located in the chloroplast genome and coding for the D1 polypeptide in the reaction center of photosystem II, was found to be tandemly duplicated in P. contorta. Cloning and sequence analysis of the two psbA genes and the surrounding regions showed that the duplicated segment is 1.97 kb long and that it ends 19 bp downstream from the psbA stop codon. The corresponding locus of P. sylvestris, which lacks the duplication, was cloned and characterized. A comparison with P. contorta indicates how the duplication/insertion event has occurred. A comparison of third codon position between P. contorta psbA and that of other plants indicated an almost equidistant evolutionary relationship between P. contorta, spinach (or barley) and Marchantia polymorpha.

  • 22. HARR, R
    et al.
    FALLMAN, P
    HAGGSTROM, M
    WAHLSTROM, L
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    GENEUS, A COMPUTER-SYSTEM FOR DNA AND PROTEIN-SEQUENCE ANALYSIS CONTAINING AN INFORMATION-RETRIEVAL SYSTEM FOR THE EMBL DATA LIBRARY1986In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 14, no 1, p. 273-284Article in journal (Refereed)
  • 23.
    Jansson, Stefan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    CHARACTERIZATION OF A LHCB5 CDNA FROM SCOTS PINE (PINUS-SYLVESTRIS)1994In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 106, no 4, p. 1695-1696Article in journal (Refereed)
  • 24.
    Jansson, Stefan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    CHARACTERIZATION OF CDNAS CORRESPONDING TO 2 LHCA4 ALLELES FROM SCOTS PINE (PINUS-SYLVESTRIS)1994In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 106, no 4, p. 1693-1694Article in journal (Refereed)
  • 25.
    Jansson, Stefan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    EVOLUTIONARY CONSERVATION OF THE CHLOROPHYLL A/B-BINDING PROTEINS - CDNAS ENCODING TYPE-I, TYPE-II, AND TYPE-III LHC-I POLYPEPTIDES FROM THE GYMNOSPERM SCOTS PINE1991In: Molecular General Genetics, ISSN 0026-8925, E-ISSN 1432-1874, Vol. 229, no 1, p. 67-76Article in journal (Refereed)
    Abstract [en]

    cDNAs encoding three different LHC I polypeptides (Type I, Type II and Type III) from the gymnosperm Scots pine (Pinus sylvestris L.) were isolated and sequenced. Comparisons of the deduced amino acid sequences with the corresponding tomato sequences showed that all three proteins were highly conserved although less so than the LHC II proteins. The similarities between mature Scots pine and tomato Types I, II and III LHC I proteins were 80%, 87% and 85%, respectively. Two of the five His residues that are found in AXXXH sequences, which have been identified as putative chlorophyll ligands in the Type I and Type II proteins, were not conserved. The same two regions of high homology between the different LHC proteins, which have been identified in tomato, were also found in the Scots pine proteins. Within the conserved regions, the Type I and Type II proteins had the highest similarity; however, the Type II and Type III proteins also showed a similarity in the central region. The results suggest that all flowering plants (gymnosperms and angiosperms) probably have the same set of LHC polypeptides. A new nomenclature for the genes encoding LHC polypeptides (formerly cab genes) is proposed. The names lha and lhb are suggested for genes encoding LHC I and LHC II proteins, respectively, analogous to the nomenclature for the genes encoding other photosynthetic proteins.

  • 26.
    Jansson, Stefan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    TYPE-I AND TYPE-II GENES FOR THE CHLOROPHYLL-A/B-BINDING PROTEIN IN THE GYMNOSPERM PINUS-SYLVESTRIS (SCOTS PINE) - CDNA CLONING AND SEQUENCE-ANALYSIS1990In: Plant Molecular Biology, ISSN 0167-4412, E-ISSN 1573-5028, Vol. 14, no 3, p. 287-296Article in journal (Refereed)
  • 27.
    Jansson, Stefan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Selstam, Eva
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    THE RAPIDLY PHOSPHORYLATED 25-KDA POLYPEPTIDE OF THE LIGHT-HARVESTING COMPLEX OF PHOTOSYSTEM-II IS ENCODED BY THE TYPE-2 CAB-II GENES1990In: Biochimica et Biophysica Acta, ISSN 0006-3002, E-ISSN 1878-2434, Vol. 1019, no 2, p. 110-114Article in journal (Refereed)
  • 28.
    Jansson, Stefan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Stefansson, H
    Nystrom, U
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Albertsson, P A
    Antenna protein composition of PS I and PS II in thylakoid sub-domains1997In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1320, no 3, p. 297-309Article in journal (Refereed)
    Abstract [en]

    Spinach thylakoids were separated into grana core, grana margin, and two different stromal lamella fractions in the absence of detergents. The levels of all light-harvesting chlorophyll a/b-binding (LHC) proteins were determined in all fractions, and were normalised to the amount of Photosystem I (PS I) and Photosystem II (PS II) centres. PS I beta in the stroma lamellae was found to have a full complement of Lhca polypeptides and, probably, one attached LHC II trimer. PS I alpha binds additional LHC II trimers, but PS I centres located in the inner parts of the grana stack lack Lhca1 and are depleted in Lhca4. PS II beta, found in grana margins and stroma lamellae, seems to associate one monomer each of Lhcb4, Lhcb5 and Lhcb6 (CP29, CP76 and CP24, respectively) and one LHC II trimer consisting of two Lhcb1 and one Lhcb3 subunit. PS II alpha has additional LHC II trimers (consisting of Lhcb1 and Lhcb2) attached. We also find evidence for the existence of both PS I and PS II centres in the extreme stroma (probably centres being synthesised or repaired), that lack all LHC proteins. (C) 1997 Published by Elsevier Science B.V.

  • 29.
    Jansson, Stefan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    VIRGIN, I
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    ANDERSSON, B
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LIGHT-INDUCED-CHANGES OF PHOTOSYSTEM-II ACTIVITY IN DARK-GROWN SCOTS PINE-SEEDLINGS1992In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 84, no 1, p. 6-12Article in journal (Refereed)
    Abstract [en]

    Both chlorophyll a and b and polypeptides of the photosynthetic apparatus are found in gymnosperm seedlings germinated and grown in absolute darkness. The photosystem II (PSII) activity is, however, limited, probably due to an inactive oxygen evolving system. In the present study dark-grown seedlings of Scots pine (Pinus sylvestris I..) were transferred to light and changes in antenna size and the activation process of PSII were investigated using fluorescence measurements and quantitative western blotting. It was found that the activation process is rapid, requires very little light and that strong light inhibits the process. It takes place without any changes in the primary reactions of PSII. Furthermore, all polypeptides except the major light-harvesting chlorophyll alb-binding protein complex of PSII (LHCII) were present in dark-grown seedlings in amounts comparable to the light treated control. The dark-grown seedlings had the same LHCII polypeptide composition as light treated seedlings, and the LHCII present seemed to be fully connected to the reaction centre. The results indicate that activation of PSII in dark-grown conifer seedlings resembles the photoactivation process of angiosperms. This implies that the fundamental processes in the assembly of the photosystem II complex is the same in all plants, but that the regulation differs between different taxa.

  • 30. Kalla, R
    et al.
    Bhalerao, RP
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Regulation of phycobilisome rod proteins and messenger-RNA at different light intensities in the cyanobacterium synechococcus 63011993In: Gene, ISSN 0378-1119, E-ISSN 1879-0038, Vol. 126, no 1, p. 77-83Article in journal (Refereed)
    Abstract [en]

    The regulation of the light-harvesting antennae, the phycobilisome (Pbs), and the cpcB1A1-cpcH-cpcI-cpcD operon encoding the structural proteins of the Pbs rod, was studied in the cyanobacterium, Synechococcus sp. PCC 6301, when grown at different light intensities (li). Pbs were purified and their linker protein (LP) profiles analyzed on SDS-polyacrylamide gels. At increasing li, the amount of the distal 30-kDa LP decreased prior to any change in the amount of the proximal 33-kDa LP, indicating a sequential increase in the Pbs rod length. While the amount of LP in the rod decreased with increasing li, the levels of the LP mRNAs increased. Post-transcriptional regulation of the expression of the polycistronic cpcB1A1-cpcH-cpcI-cpcD mRNA was inferred from these observations. The half-life of the mRNAs studied was typically found to be 7 min with four exceptions: (1 and 2) the half-lives for the 3.4- and 3.7-kb polycistronic LP mRNAs were 16 and 1 min at the low (lli) and high li (hli), respectively; (3) the half-life of the 1.4-kb cpcB1A1 mRNA was 2 min at lli; and (4) the 1.3-kb cpcB1A1 transcript had a half-life of 10 min at lli. At hli, it was found that the 1.3-kb cpcB1A1 transcript did not start to disappear until the amount of the 1.4-kb cpcB1A1 transcript had reached the level equal to that of the 1.3-kb mRNA, implying that the 1.4-kb transcript might be processed to the 1.3-kb form.

  • 31. KALLA, R
    et al.
    LIND, LK
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    GENETIC-ANALYSIS OF PHYCOBILISOME MUTANTS IN THE CYANOBACTERIUM SYNECHOCOCCUS SPECIES PCC-63011989In: Molecular Microbiology, ISSN 0950-382X, E-ISSN 1365-2958, Vol. 3, no 3, p. 339-347Article in journal (Refereed)
  • 32. KALLA, SR
    et al.
    LIND, LK
    LIDHOLM, J
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    TRANSCRIPTIONAL ORGANIZATION OF THE PHYCOCYANIN SUBUNIT GENE CLUSTERS OF THE CYANOBACTERIUM ANACYSTIS-NIDULANS UTEX-6251988In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 170, no 7, p. 2961-2970Article in journal (Refereed)
  • 33. KALLA, SR
    et al.
    LONNEBORG, A
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LIGHT-MODULATED ANTENNAE ACCLIMATION IN THE CYANOBACTERIUM ANACYSTIS-NIDULANS - EFFECTS OF TRANSCRIPTIONAL AND TRANSLATIONAL INHIBITORS1986In: JOURNAL OF GENERAL MICROBIOLOGY, ISSN 0022-1287, Vol. 132, p. 3195-3200Article in journal (Refereed)
  • 34. KROL, M
    et al.
    SPANGFORT, MD
    HUNER, NPA
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    CHLOROPHYLL A/B-BINDING PROTEINS, PIGMENT CONVERSIONS, AND EARLY LIGHT-INDUCED PROTEINS IN A CHLOROPHYLL B-LESS BARLEY MUTANT1995In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 107, no 3, p. 873-883Article in journal (Refereed)
    Abstract [en]

    Monospecific polyclonal antibodies have been raised against synthetic peptides derived from the primary sequences from different plant light-harvesting Chl a/b-binding (LHC) proteins. Together with other monospecific antibodies, these were used to quantify the levels of the 10 different LHC proteins in wild-type and chlorina 12 barley (Hordeum vulgare L.), grown under normal and intermittent light (ImL). Chlorina 12, grown under normal light, lacked Lhcb1 (type I LHC II) and Lhcb6 (CP24) and had reduced amounts of Lhcb2, Lhcb3 (types II and III LHC II), and Lhcb4 (CP 29). Chlorina f2 grown under ImL lacked all LHC proteins, whereas wild-type ImL plants contained Lhcb5 (CP 26) and a small amount of Lhcb2. The chlorina f2 ImL thylakoids were organized in large parallel arrays, but wild-type ImL thylakoids had appressed regions, indicating a possible role for Lhcb5 in grana stacking. Chlorina f2 grown under ImL contained considerable amounts of violaxanthin (2-3/reaction center), representing a pool of phototransformable xanthophyll cycle pigments not associated with LHC proteins. Chlorina f2 and the plants grown under ImL also contained early light-induced proteins (ELIPs) as monitored by western blotting. The levels of both ELIPs and xanthophyll cycle pigments increased during a 1 h of high light treatment, without accumulation of LHC proteins. These data are consistent with the hypothesis that ELIPs are pigment-binding proteins, and we suggest that ELIPs bind photoconvertible xanthophylls and replace ''normal'' LHC proteins under conditions of light stress.

  • 35. KRUPA, Z
    et al.
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    PHOTOINHIBITION AND RECOVERY OF PHOTOSYNTHESIS IN PSBA GENE-INACTIVATED STRAINS OF CYANOBACTERIUM ANACYSTIS-NIDULANS1990In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 93, no 1, p. 1-6Article in journal (Refereed)
  • 36. KRUPA, Z
    et al.
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    PHOTOINHIBITION OF PHOTOSYNTHESIS AND GROWTH-RESPONSES AT DIFFERENT LIGHT LEVELS IN PSBA GENE MUTANTS OF THE CYANOBACTERIUM SYNECHOCOCCUS1991In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 82, no 1, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Photoinhibition of photosynthesis and growth responses at different light levels (10, 120 and 250-mu-mol m-2 s-1) were studied in psbA gene mutants R2S2C3 (psbAI gene present) and R2K1 (psbAII/psbAIII genes present) of the cyanobacterium Synechococcus sp. PCC 7942 (Anacystis nidulans R2). Mutant R2K1 (possessing form II of the D1 protein of photosystem II) was much more resistant to photoinhibition than the mutant R2S2C3 (possessing form I of the D1 protein). At moderate inhibitory light levels (100 to 300-mu-mol m-2 s-1) this was largely ascribed to an increased resistance of the photosystem II reaction centres possessing form II of the D1 protein. However, at higher light levels the higher resistance of mutant R2K1 was assigned to a higher rate of photosystem II repair, i.e. turnover of the D1 protein. Moreover, our results support the hypothesis that photoinhibition of photosystem II and photoinhibitory induced quenching are due to separate processes. Results from growth experiments show that the R2K1 mutant has a slower growth rate than the R2S2C3 mutant but shows an increased survival under high light stress conditions. It is hypothesized that high resistance to photoinhibition, though allowing a better survival under high light, is not advantageous for optimal growth.

  • 37. LIDHOLM, J
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    A 3-STEP MODEL FOR THE REARRANGEMENT OF THE CHLOROPLAST TRNK-PSBA REGION OF THE GYMNOSPERM PINUS-CONTORTA1991In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 19, no 11, p. 2881-2887Article in journal (Refereed)
    Abstract [en]

    A region of the Pinus contorta chloroplast genome which contains a duplication of the psbA gene was characterized. From previous experiments it was known that the two copies of the psbA gene were located approximately 3.3 kilobase pairs (kbp) apart, that they had the same orientation and that one endpoint of the duplication was 19 base pairs (bp) downstream of the psbA stop codon. In order to determine the size and additional genetic content of the duplicated segment, both copies as well as the intervening DNA were sequenced completely. It was found that the duplicated segment was 1969 bp long, that the two copies were completely identical and were separated by 2431 bp. The duplicated segment carried, in addition to psbA, the 3' exon of the trnK gene, which was partially included in a 124 bp direct repeat. The translocated copy of the duplicated segment was found to be inserted upstream of the trnK(UUU) gene and was immediately followed by a repeated 41 bp stretch from the psbA coding region. The trnK gene was split by a 2509 bp intron which contained an open reading frame of 515 codons. Sequence comparisons of the duplicated segment and its flanking DNA to the corresponding regions of P. sylvestris, a species which lacks the rearrangements found in P. contorta, made it possible to identify 3-9 bp homologies within which recombinations has occurred. A model was derived which would accommodate the conversion of a trnK-psbA locus of the ancestral, P. sylvestris-like organization into the rearranged structure found in P. contorta.

  • 38. LIDHOLM, J
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    A FUNCTIONAL PROMOTER SHIFT OF A CHLOROPLAST GENE - A TRANSCRIPTIONAL FUSION BETWEEN A NOVEL PSBA GENE COPY AND THE TRNK(UUU) GENE IN PINUS-CONTORTA1992In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 2, no 6, p. 875-886Article in journal (Refereed)
    Abstract [en]

    A comparative transcription analysis of the chloroplast trnK-psbA-trnH region of the two pine species Pinus contorta and Pinus sylvestris is reported. The chloroplast genome of P. contorta has previously been shown to contain a duplicated psbA gene copy integrated closely upstream of the split trnK gene. This rearrangement has resulted in the gene order psbAI-trnK-psbAII-trnH, where psbAII is the ancestral psbA gene copy. In P. sylvestris, a species which lacks the psbA duplication, transcription of the trnK gene originates from a position 291 bp upstream of the trnK 5' exon, adjacent to a canonical promoter structure. In P. contorta, the corresponding promoter structure has been separated from the trnK gene by the insertion of psbAI, and has, in addition, been partially deleted. Analysis of the transcriptional organization of the trnK-psbA-trnH region of the two pine species revealed that the trnK gene in P. contorta is transcriptionally fused to the inserted psbA/gene copy. As a result, trnK is under the control of the psbA promoter in this species and has therefore acquired psbA-like expression characteristics. In P. sylvestris, accumulation of trnK transcripts is not significantly higher in light-grown than in dark-grown seedlings. In contrast, the level of trnK transcripts in P. contorta is approximately 12-fold higher in the light than in the dark. When light-grown seedlings of the two pine species were compared, an approximately 20-fold higher level of trnK RNAs was found in P. contorta. In both pine species, evidence was obtained for trnK-psbA and psbA-trnH co-transcription.

  • 39. LIDHOLM, J
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    HOMOLOGS OF THE GREEN ALGAL GIDA GENE AND THE LIVERWORT FRXC GENE ARE PRESENT ON THE CHLOROPLAST GENOMES OF CONIFERS1991In: Plant Molecular Biology, ISSN 0167-4412, E-ISSN 1573-5028, Vol. 17, no 4, p. 787-798Article in journal (Refereed)
    Abstract [en]

    Strong hybridization signals were obtained from total DNA of two conifers, lodgepole pine (Pinus contorta) and Norway spruce (Picea abies), in a Southern blot analysis using a probe derived from the chloroplast gidA gene of the green alga Chlamydomonas reinhardtii. The pine fragments detected by the probe were found to originate from the chloroplast genome and, as judged by the signal intensity, this was also true for the spruce fragments. Sequence analysis of the hybridizing pine chloroplast DNA region revealed an open reading frame potentially encoding a 459 amino acid polypeptide, highly homologous to that deduced from the algal gene and to ORF465 of liverwort chloroplast DNA. Upstream of the gidA sequence, we found a trnN(GUU) gene and an open reading frame of 291 codons which was 78% identical to the frxC gene of liverwort. Since ORF465 is located immediately downstream of trnN and frxC in liverwort, the genetic organization of this region is very similar in the two plants. In contrast, neither the gidA nor the frxC gene is present in the chloroplast DNA of tobacco or rice. It was recently reported that deletions in the gidA region of the chloroplast genome of Chlamydomonas reinhardtii abolish the light-independent pathway of chlorophyll synthesis which exists in many algae and lower plants. The presence of the gidA gene on the chloroplast genomes of conifers may therefore be of significance with respect to the ability of these plants to synthesize chlorophyll in the dark.

  • 40. LIDHOLM, J
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    THE CHLOROPLAST GENOME OF THE GYMNOSPERM PINUS-CONTORTA - A PHYSICAL MAP AND A COMPLETE COLLECTION OF OVERLAPPING CLONES1991In: Current Genetics, ISSN 0172-8083, E-ISSN 1432-0983, Vol. 20, no 1-2, p. 161-166Article in journal (Refereed)
    Abstract [en]

    Overlapping restriction fragments of chloroplast DNA from the conifer Pinus contorta were cloned. Out of a total of 49 clones, 33 comprise the minimum set required to represent the entire genome. Using the purified inserts of these clones as probes in filter hybridizations, all sites for the three restriction enzymes KpnI, HpaI and SacI in the P. contorta chloroplast genome were mapped. Heterologous filter hybridizations and sequence analysis of some of the P. contorta clones were used to determine the position of 15 genes on the restriction map. The size of the genome, which lacks an inverted repeat organization, was found to be approximately 121 kilobase pairs (kbp). Unusual features of this genome are a duplication of the psbA gene and the presence of two genes, gidA and frxC, which are not found in angiosperms. The genome appeared essentially colinear with that of Pinus radiata, for which a map has previously been published. Two different restriction fragment length polymorphisms were found to be produced by variable numbers of copies of 124 bp- and 150 bp-long, tandemly repeated elements.

  • 41. LIDHOLM, J
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    PHOTOINHIBITION OF PHOTOSYNTHESIS AND ITS RECOVERY IN THE GREEN-ALGA CHLAMYDOMONAS-REINHARDII1987In: Plant and Cell Physiology, ISSN 0032-0781, E-ISSN 1471-9053, Vol. 28, no 6, p. 1133-1140Article in journal (Refereed)
  • 42. LIDHOLM, J
    et al.
    SZMIDT, A
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    DUPLICATION OF THE PSBA GENE IN THE CHLOROPLAST GENOME OF 2 PINUS SPECIES1991In: Molecular General Genetics, ISSN 0026-8925, E-ISSN 1432-1874, Vol. 226, no 3, p. 345-352Article in journal (Refereed)
    Abstract [en]

    The psbA gene, encoding the D1 protein of photosystem II, was found to be duplicated in the chloroplast genome of two pine species, Pinus contorta and P. banksiana. Analysis of cloned overlapping restriction fragments of P. contorta chloroplast DNA showed that the two psbA genes have the same orientation and are separated by approximately 3.3 kb. The nucleotide sequences of the coding and the upstream regions of the two psbA copies were found to be identical, whereas the downstream sequences diverged from a point 20 bp 3' of the stop codons. Downstream of the gene copy designated psbAII, a dyad symmetry which allows the formation of a strong mRNA hairpin structure, and a trnH gene were found. No such elements, which are characteristic of psbA downstream regions, were found 3' of psbAI. This suggests that psbAII is the ancestral gene copy in P. contorta. Upon comparison with psbA from other plants, the pine 353-codon sequence appeared almost as distant from the angiosperm as from the liverwort counterpart. As compared to tobacco, 14 substitutions in the predicted amino acid sequence were found, most of which were located in the terminal regions of the protein.

  • 43. LIDHOLM, J
    et al.
    SZMIDT, AE
    HALLGREN, JE
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    THE CHLOROPLAST GENOMES OF CONIFERS LACK ONE OF THE RRNA-ENCODING INVERTED REPEATS1988In: Molecular General Genetics, ISSN 0026-8925, E-ISSN 1432-1874, Vol. 212, no 1, p. 6-10Article in journal (Refereed)
  • 44. LIND, LK
    et al.
    KALLA, SR
    LONNEBORG, A
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    CLONING OF THE BETA-PHYCOCYANIN GENE FROM ANACYSTIS-NIDULANS1985In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 188, no 1, p. 27-32Article in journal (Refereed)
  • 45. LIND, LK
    et al.
    KALLA, SR
    LONNEBORG, A
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    CLONING OF THE BETA-PHYCOCYANIN GENE FROM ANACYSTIS-NIDULANS1985In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 188, no 1, p. 27-32Article in journal (Refereed)
  • 46. LONNEBORG, A
    et al.
    KALLA, SR
    Samuelsson, Göran
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LIGHT-REGULATED EXPRESSION OF THE PSB A TRANSCRIPT IN THE CYANOBACTERIUM ANACYSTIS-NIDULANS1988In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 240, no 1-2, p. 110-114Article in journal (Refereed)
  • 47. LONNEBORG, A
    et al.
    KALLA, SR
    Samuelsson, Göran
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LIGHT-REGULATED EXPRESSION OF THE PSB A TRANSCRIPT IN THE CYANOBACTERIUM ANACYSTIS-NIDULANS1988In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 240, no 1-2, p. 110-114Article in journal (Refereed)
  • 48. LONNEBORG, A
    et al.
    KALLA, SR
    Samuelsson, Göran
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LIGHT-REGULATED EXPRESSION OF THE PSB A TRANSCRIPT IN THE CYANOBACTERIUM ANACYSTIS-NIDULANS1988In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 240, no 1-2, p. 110-114Article in journal (Refereed)
  • 49. LONNEBORG, A
    et al.
    LIND, LK
    KALLA, SR
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oquist, Gunnar
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    ACCLIMATION PROCESSES IN THE LIGHT-HARVESTING SYSTEM OF THE CYANOBACTERIUM ANACYSTIS-NIDULANS FOLLOWING A LIGHT SHIFT FROM WHITE TO RED-LIGHT1985In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 78, no 1, p. 110-114Article in journal (Refereed)
  • 50. Mouillon, Jean-Marie
    et al.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Harryson, Pia
    Structural investigation of disordered stress proteins. Comparison of full-length dehydrins with isolated peptides of their conserved segments.2006In: Plant Physiology, ISSN 0032-0889, Vol. 141, no 2, p. 638-50Article in journal (Refereed)
    Abstract [en]

    Dehydrins constitute a class of intrinsically disordered proteins that are expressed under conditions of water-related stress. Characteristic of the dehydrins are some highly conserved stretches of seven to 17 residues that are repetitively scattered in their sequences, the K-, S-, Y-, and Lys-rich segments. In this study, we investigate the putative role of these segments in promoting structure. The analysis is based on comparative analysis of four full-length dehydrins from Arabidopsis (Arabidopsis thaliana; Cor47, Lti29, Lti30, and Rab18) and isolated peptide mimics of the K-, Y-, and Lys-rich segments. In physiological buffer, the circular dichroism spectra of the full-length dehydrins reveal overall disordered structures with a variable content of poly-Pro helices, a type of elongated secondary structure relying on bridging water molecules. Similar disordered structures are observed for the isolated peptides of the conserved segments. Interestingly, neither the full-length dehydrins nor their conserved segments are able to adopt specific structure in response to altered temperature, one of the factors that regulate their expression in vivo. There is also no structural response to the addition of metal ions, increased protein concentration, or the protein-stabilizing salt Na2SO4. Taken together, these observations indicate that the dehydrins are not in equilibrium with high-energy folded structures. The result suggests that the dehydrins are highly evolved proteins, selected to maintain high configurational flexibility and to resist unspecific collapse and aggregation. The role of the conserved segments is thus not to promote tertiary structure, but to exert their biological function more locally upon interaction with specific biological targets, for example, by acting as beads on a string for specific recognition, interaction with membranes, or intermolecular scaffolding. In this perspective, it is notable that the Lys-rich segment in Cor47 and Lti29 shows sequence similarity with the animal chaperone HSP90.

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