336 research outputs found
Cytoplasmic N-Terminal Protein Acetylation Is Required for Efficient Photosynthesis in Arabidopsis
No full textThe Arabidopsis atmak3-1 mutant was identified on the basis of a decreased effective quantum yield of photosystem II. In atmak3-1, the synthesis of the plastome-encoded photosystem II core proteins D1 and CP47 is affected, resulting in a decrease in the abundance of thylakoid multiprotein complexes. DNA array-based mRNA analysis indicated that extraplastid functions also are altered. The mutation responsible was localized to AtMAK3, which encodes a homolog of the yeast protein Mak3p. In yeast, Mak3p, together with Mak10p and Mak31p, forms the N-terminal acetyltransferase complex C (NatC). The cytoplasmic AtMAK3 protein can functionally replace Mak3p, Mak10p, and Mak31p in acetylating N termini of endogenous proteins and the L-A virus Gag protein. This result, together with the finding that knockout of the Arabidopsis MAK10 homolog does not result in obvious physiological effects, indicates that AtMAK3 function does not require NatC complex formation, as it does in yeast. We suggest that N-acetylation of certain chloroplast precursor protein(s) is necessary for the efficient accumulation of the mature protein(s) in chloroplasts
Financial Underpinnings of Europe’s Financial Crisis
No full textThis book analyzes how financial liberalization affected the development of the financial crisis in Europe, with particular attention given to the ways in which power asymmetries within Western Europe facilitated financial liberalization and distributed the costs and gains from it. The author combines institutional narrative analysis with empirical surveys and econometrics, as well as country-level studies of financial liberalization and its consequences before and after the 2008 Global Financial Crisis
The Chloroplast Gene ycf9 Encodes a Photosystem II (PSII) Core Subunit, PsbZ, that Participates in PSII Supramolecular Architecture
No full textWe have characterized the biochemical nature and the function of PsbZ, the protein product of a ubiquitous open reading frame, which is known as ycf9 in Chlamydomonas and ORF 62 in tobacco, that is present in chloroplast and cyanobacterial genomes. After raising specific antibodies to PsbZ from Chlamydomonas and tobacco, we demonstrated that it is a bona fide photosystem II (PSII) subunit. PsbZ copurifies with PSII cores in Chlamydomonas as well as in tobacco. Accordingly, PSII mutants from Chlamydomonas and tobacco are deficient in PsbZ. Using psbZ-targeted gene inactivation in tobacco and Chlamydomonas, we show that this protein controls the interaction of PSII cores with the light-harvesting antenna; in particular, PSII-LHCII supercomplexes no longer could be isolated from PsbZ-deficient tobacco plants. The content of the minor chlorophyll binding protein CP26, and to a lesser extent that of CP29, also was altered substantially under most growth conditions in the tobacco mutant and in Chlamydomonas mutant cells grown under photoautotrophic conditions. These PsbZ-dependent changes in the supramolecular organization of the PSII cores with their peripheral antennas cause two distinct phenotypes in tobacco and are accompanied by considerable modifications in (1) the pattern of protein phosphorylation within PSII units, (2) the deepoxidation of xanthophylls, and (3) the kinetics and amplitude of nonphotochemical quenching. The role of PsbZ in excitation energy dissipation within PSII is discussed in light of its proximity to CP43, in agreement with the most recent structural data on PSII
rG-CSF reduces endotoxemia and improves survival during<i>E. coli</i>pneumonia
No full textFreeman, Bradley D., Zenaide Quezado, Fabrice Zeni, Charles Natanson, Robert L. Danner, Steven Banks, Marcello Quezado, Yvonne Fitz, John Bacher, and Peter Q. Eichacker. rG-CSF reduces endotoxemia and improves survival during E. coli pneumonia. J. Appl. Physiol. 83(5): 1467–1475, 1997.—We investigated the effects of recombinant granulocyte colony-stimulating factor (rG-CSF) during canine bacterial pneumonia. Beagles with chronic tracheostomies received daily subcutaneous rG-CSF (5 μg/kg body wt) or placebo for 14 days, beginning 9 days before intrabronchial inoculation with E. coli. Animals received antibiotics and fluid support; a subset received humidified oxygen (fractional inspired O20.40). Compared with controls, rG-CSF increased circulating neutrophil counts (57.4 vs. 11.0 × 103/mm3, day 1 after infection; P = 0.0001), decreased plasma endotoxin (7.5 vs. 1.1 EU/ml at 8 h; P< 0.01) and serum tumor necrosis factor-α (3,402 vs. 729 pg/ml at 2 h; P = 0.01) levels, and prolonged survival (relative risk of death = 0.45, 95% confidence interval 0.21–0.97; P = 0.038). Also, rG-CSF attenuated sepsis-associated myocardial dysfunction ( P < 0.001). rG-CSF had no effect on pulmonary function or on blood and lung bacteria counts (all P = not significant). Other animals challenged with endotoxin (4 mg/kg iv) after similar treatment with rG-CSF had lower serum endotoxin levels (7.62 vs. 5.81 log EU/ml at 6 h; P < 0.01) and less cardiovascular dysfunction ( P < 0.05 to < 0.002) but similar tumor necrosis factor-α levels ( P = not significant) compared with controls. Thus prophylactic rG-CSF sufficient to increase circulating neutrophils during bacterial pneumonia may improve cardiovascular function and survival by mechanisms that in part enhance the clearance of bacterial toxins but do not improve lung function.</jats:p
The proteome of the heterocyst cell wall in Anabaena sp. PCC 7120
No full textAnabaena sp. PCC 7120 is a filamentous cyanobacterium that serves as a model to analyze prokaryotic cell differentiation, evolutionary development of plastids, and the regulation of nitrogen fixation. The cell wall is the cellular structure in contact with the surrounding medium. To understand the dynamics of the cell wall proteome during cell differentiation, the cell wall from Anabaena heterocysts was enriched and analyzed. In line with the recently proposed continuity of the outer membrane along the Anabaena filament, most of the proteins identified in the heterocyst cell-wall fraction are also present in the cell wall of vegetative cells, even though the lipid content of both membranes is different
Cloning and characterisation of chlorophyll synthase from Avena sativa
No full textThe chlorophyll synthase gene from oat (Avena sativa) was cloned and expressed in Escherichia coli. The deduced amino acid sequence consists of 378 amino acids including a presequence, of 46 amino acids. Deletion mutants show that a core protein comprising amino acid residues 88 to 377 is enzymatically active. The sequence of the mature protein shows 85% identity with the chlorophyll synthase of Arabidopsis thaliana and 62% identity with the chlorophyll synthase of Synechocystis PCC 6803. The gene is constitutively expressed as the same transcript level is found in dark-grown and in light-grown seedlings. The enzyme requires magnesium ions for activity; manganese ions can reconstitute only part of the activity. Diacetyl and N-phenylmaleimide (NPM) inhibit the enzyme activity. Site-directed mutagenesis reveals that, out of the 4 Arg residues present in the active core protein, Arg-91 and Arg-161 are essential for the activity. Five cysteine residues are present in the core protein, of which only Cys-109 is essential for the enzyme activity. Since the wild-type and all other Cys-mutants with the exception of the mutant C304A are inhibited by N-phenylmaleimide, we conclude that the inhibitor binds to a non-essential Cys residue to abolish activity. The role of the various Arg and Cys residues is discussed
Stabilization of the chlorophyll binding apoproteins, P700, CP47, CP43, D2, and D1, by synthesis of Zn-pheophytin a in intact etioplasts from barley
No full textAbstractChlorophyll a was compared with Zn-pheophytin a for stabilization of chlorophyll binding apoproteins, P700, CP47, CP43, D2, and D1, in intact etioplasts from barley (Hordeum vulgare L.). Intact etioplasts were shown to effectively translate the chlorophyll apoproteins, to take up and esterify the exogenously added substrates, chlorophyllide a and Zn-pheophorbide a, with geranylgeraniolpyrophosphate. For stabilization of P700, CP47, D2, and D1, the product, Zn-pheophytin a, was shown to substitute for chlorophyll a. Stabilization of CP43 was selectively increased in the presence of Zn-pheophytin a. The degree of stabilization was shown to depend on the amount of newly synthesized Zn-pheophytin a and on the central atom of the chlorophyll molecule
Bacterial meningitis: the role of transforming growth factor-Beta in innate immunity and secondary brain damage
No full textProject 6 of the NCCR 'Neural Plasticity and Repair' focuses on mechanisms of immunity and tissue damage in autoimmune and infectious diseases of the central nervous system (CNS). In one of the subprojects, the influence of transforming growth factor-beta (TGF-beta) on the immune reactivity of the CNS was investigated. In mice with Streptococcus pneumoniae-induced meningitis, a deletion of TGF-beta receptor II on leukocytes is found to enhance recruitment of neutrophils to the site of infection and to promote bacterial clearance. The improved host defense against S. pneumoniae was associated with an almost complete prevention of meningitis-induced vasculitis, a major intracranial complication leading to brain damage. The data show that endogenous TGF-beta suppresses host defense against bacterial infection in the CNS. This contrasts with findings from other body compartments that suggested that TGF-beta is a powerful chemotactic cytokine and increases microbial clearance
Evaluation Of Metal-ion Stress In Sunflower (helianthus Annuus L.) Leaves Through Proteomic Changes
No full textIn this work, sunflowers (Helianthus annuus L.) were cultivated using soil and vermicompost as substrate, and plant irrigation was carried out using either a Zn solution or a mixed ions solution (Cd, Cu, Pb and Zn). After plant harvesting, the effects of metal-ion contamination on proteins expression (either up- or down-regulation) in sunflower leaves were evaluated using two-dimensional electrophoresis (2-DE), gel images and mass spectrometry (MALDI-QTOF MS). When Zn or mixed ions solution was added to the substrate, nine proteins showed different expressions. Another twenty-three protein spots also showed considerable variation when both treatments (Zn or mixed ions) were applied. Twelve of these proteins were successfully characterized, six of them being reported for the first time in Helianthus annuus L. Two other proteins showed new sequences that have been downloaded to the protein databank. © The Royal Society of Chemistry 2009.11107113Gopal, R., Rizvi, A.H., (2008) Chemosphere, 70, pp. 1539-1544Garcia, J.S., De Magalhães, C.S., Arruda, M.A.Z., (2006) Talanta, 69, pp. 1-15Sousa, A.I., Caador, I., Lillebø, A.I., Pardal, M.A., (2008) Chemosphere, 70, pp. 850-857Benavides, M.P., Gallego, S.M., Tomaro, M.L., (2005) Braz. J. Plant Physiol., 17, pp. 21-34Gratão, P.L., Polle, A., Lea, P.J., Azevedo, R.A., (2005) Funct. Plant Biol., 32, pp. 481-494Arora, A., Sairam, R.K., Srivastava, G.C., (2002) Curr. Sci. India, 82, pp. 1227-1238Ahsan, N., Lee, D.G., Lee, S.H., Kang, K.Y., Lee, J.J., Kim, P.J., Yoon, H.S., Lee, B.H., (2007) Chemosphere, 67, pp. 1182-1193Caruso, G., Cavaliere, C., Guarino, C., Gubbiotti, R., Foglia, P., Lagana, A., (2008) Anal. Bioanal. Chem., 391, pp. 381-391Labra, M., Gianazza, E., Waitt, R., Eberini, I., Sozzi, A., Regondi, S., Grassi, F., Agradi, E., (2006) Chemosphere, 62, pp. 1234-1244Sussulini, A., Souza, G.H.M.F., Eberlin, M.N., Arruda, M.A.Z., (2007) J. Anal. At. Spectrom., 22, pp. 1501-1506Garcia, J.S., Gratão, P.L., Azevedo, R.A., Arruda, M.A.Z., (2006) J. Agric. Food Chem., 54, pp. 8623-8630Bradford, M.M., (1976) Anal. Biochem., 72, pp. 248-254Berkelman, T., Stenstedt, T., (1998) 2-D Electrophoresis - Principles and Methods, , Amersham Biosciences, UppsalaCandiano, G., Bruschi, M., Musante, L., Santucci, L., Ghiggeri, G.M., Carnemolla, B., Orecchia, P., Righetti, P.G., (2004) Electrophoresis, 25, pp. 1327-1333Onnerfjord, P., Ekstrom, S., Bergquist, J., Nilsson, J., Laurell, T., Marko-Varga, G., (1999) Rapid Commun. Mass Spectrom., 13, pp. 315-322Granvogl, B., Plöscher, M., Eichacker, L.A., (2007) Anal. Bioanal. Chem., 389, pp. 991-1002Childs, K.L., Hamilton, J.P., Zhu, W., Ly, E., Cheung, F., Wu, H., Rabinowicz, P.D., Chan, A.P., (2007) Nucleic Acids Res., 35, pp. 846-D85Parker, R., Flowers, T.J., Moore, A.L., Harpham, N.V.J., (2006) J. Exp. Bot., 57, pp. 1109-1118Eravci, M., Fuxius, S., Broedel, O., Weist, S., Eravci, S., Mansmann, U., Schuter, H., Baumgartner, A., (2007) Proteomics, 7, pp. 513-523Dea-Wook, K., Rakwai, R., Agrawal, G.K., Young-Ho, J., Shibato, J., Nam-Soo, J., Iwahashi, Y., Usui, K., (2005) Electrophoresis, 26, pp. 4521-4539Sarry, J.E., Kuhn, L., Ducruix, C., Lafaye, A., Junot, C., Hugouvieux, V., Jourdain, A., Bourguignon, J., (2006) Proteomics, 6, pp. 2180-2198Tuomainen, M.H., Nunan, N., Lehesranta, S.J., Tervahauta, A.I., Hassinen, V.H., Schat, H., Koistinen, K.M., Kärenlampi, S.O., (2006) Proteomics, 6, pp. 3696-3706. , http://www.expasy.org, Expasy Proteomics Server-Aina, R., Labra, M., Fumagalli, P., Vannini, C., Marsoni, M., Cucchi, U., Bracale, M., Citterio, S., (2007) Environ. Exp. Bot., 59, pp. 381-392Roth, U., Von Roepenack-Lahaye, E., Clemens, S., (2006) J. Exp. Bot., 57, pp. 4003-401
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