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Arruda P, Rodrigues R, Felipe M. Alternative protocols testing for sugarcane hemicellulosic hydrolysate detoxification. N Biotechnol 2009. [DOI: 10.1016/j.nbt.2009.06.597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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2
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Grivet L, Glaszmann JC, Vincentz M, da Silva F, Arruda P. ESTs as a source for sequence polymorphism discovery in sugarcane: example of the Adh genes. Theor Appl Genet 2003; 106:190-7. [PMID: 12582843 DOI: 10.1007/s00122-002-1075-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2002] [Accepted: 05/06/2002] [Indexed: 05/23/2023]
Abstract
Expressed sequence tags (ESTs) have proven to be a valuable tool to discover single nucleotide polymorphism (SNP) in human genes but their use for this purpose is still limited in higher plants. Using a database of approximately 250,000 sugarcane ESTs we have recovered 219 sequences encoding alcohol dehydrogenases ( Adh), which tagged 178 distinct cDNAs from 27 libraries, constructed from at least four different cultivars. The partitioning of these ESTs into paralogous genes revealed three Adh genes expressed in sugarcane, one Adh2 and two Adh1. The soundness of the partition was carefully checked by comparison to external data, especially from the closely related sorghum. Analysis of polymorphism in the alignments of EST sequences revealed a total of 37 highly reliable SNPs in the coding and untranslated regions of the three Adh genes. In the coding regions, the mean occurrence of SNPs was one for every 122 base pair. A total of eight insertion-deletions was observed, their occurrence being limited to untranslated regions. These results show that EST data constitute an invaluable source of sequence polymorphism for sugarcane that is worth carefully collecting for the future development of new marker tools.
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Affiliation(s)
- L Grivet
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, PO Box 6010, 13083-970 Campinas, SP, Brazil.
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3
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Abstract
Uncoupling proteins (UCPs) belong to a distinct cluster of the mitochondrial anion carrier family. Up to five different uncoupling protein types were found in mitochondria of mammals and plants, and recently in fishes, fungi and protozoa. They exhibit a significantly conserved structure with several motifs specific to either the whole cluster or protein type. Uncoupling proteins, as well as the whole mitochondrial anion carrier gene family, probably emerged in evolution before the separation of animal, fungi, and plant kingdoms and originate from an anion/nucleotide or anion/anion transporter ancestor. Mammalian UCP1, UCP2, UCP3, and plant uncoupling proteins pUCP1 and pUCP2 are similar and seem to form one subgroup, whereas UCP4 and BMCP1 belong to a different group. Molecular, biochemical, and phylogenic data suggest that UCP2 could be considered as an UCP-prototype. UCP1 plays its biological role mainly in the non-shivering thermogenesis while the role of the other types is unknown. However, hypotheses have suggested that they are involved in the general balance of basic energy expenditure, protection from reactive oxygen species, and, in plants, in fruit ripening and seed ontogeny.
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Affiliation(s)
- J Borecký
- Department of Membrane Transport Biophysics. Institute of Physiology, Academy of Sciences of the Czech Republic, Prague
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4
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Freitas DS, Maia IG, Arruda P, Vega J. Molecular characterisation and evolutionary relationships of a potyvirus infecting Crotalaria in Brazil. Brief report. Arch Virol 2002; 147:411-7. [PMID: 11890532 DOI: 10.1007/s705-002-8329-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The 3' terminal genomic region of a potyvirus causing mosaic disease in several Crotalaria species has been cloned and sequenced. Comparisons of the nucleotide and deduced amino acid (aa) sequences of the cloned cDNA with those from other potyviruses show that the Crotalaria-infecting virus (designated Crotalaria mosaic virus; CrMV) is closely related to Cowpea aphid-borne mosaic virus (CABMV). Maximum identity (95.4%) at the coat protein (CP) aa level was observed between CrMV and a Brazilian strain of CABMV. Phylogenetic analyses derived from the sequence alignments of the CP and 3' untranslated region confirmed the identification of CrMV as a strain of CABMV and the name CABMV-Cr is suggested.
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Affiliation(s)
- D S Freitas
- Departamento de Fisiologia Vegetal, Universidade Estadual de Campinas, SP, Brazil
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5
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Abstract
This paper presents preliminary results demonstrating the use of the sugarcane expressed sequence tag (EST) database (SUCEST) to detect single nucleotide polymorphisms (SNPs) inside 6-phosphogluconate dehydrogenase genes (Pgds). Sixty-four Pgd-related EST sequences were identified and partitioned into two clear-cut sets of 14 and 50 ESTs, probably corresponding to two genes, A and B, respectively. Alignment of A sequences allowed the detection of a single SNP while alignment of B sequences permitted the detection of 39 reliable SNPs, 27 of which in the coding sequence of the gene. Thirty-eight SNPs were binucleotidic and a single one was trinucleotidic. Nine insertions/deletions from one to 72 base pairs long were also detected in the noncoding 3’ and 5’ sequences. The soundness and the consequences of those preliminary observations on sequence polymorphism in sugarcane are discussed.
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Affiliation(s)
- L. Grivet
- Universidade Estadual de Campinas, Brazil
| | | | - P. Arruda
- Universidade Estadual de Campinas, Brazil; Universidade Estadual de Campinas, Brazil
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6
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Abstract
The role of calmodulin on Al toxicity was studied in two maize (Zea mays L.) inbred lines, Cat 100-6 (Al-tolerant) and S 1587-17 (Al-sensitive). Increasing levels of Al induced the release of malate at similar rate by roots of both genotypes, while the exudation of citrate, a stronger Al-binding compound, was 3.5 times higher in Cat 100-6 seedlings exposed to 16.2x10(-6) Al(3+) activity. The calmodulin inhibitor trifluoperazine significantly reduced the root growth in both genotypes, mimicking the main effect of Al. However, when Cat 100-6 and S 1587-17 seedlings were challenged with Al in conjunction with trifluoperazine, no further reduction in root growth or any other effect of Al toxicity was observed. The rate of Al-induced citrate exudation by both genotypes was not affected by treatment with trifluoperazine or calmidazolium, another calmodulin inhibitor. The Al(3+) interaction with cytoplasmic CaM was estimated using models for the binding of Al(3+) and Mg(2+) with CaM and physiological concentrations of citrate, CaM, InsP(3), ATP, ADP, Al(3+) and Mg(2+). In this simulation, Al(3+) associated with citrate and InsP(3), but not with CaM. We conclude that calmodulin is not relevant to the physiological processes leading to the Al tolerance in maize, nor is it a primary target for Al toxicity.
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Affiliation(s)
- R A Jorge
- Universidade Estadual de Campinas, UNICAMP, Instituto de Química, Departamento de Físico-Química, SP, Campinas, Brazil.
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7
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da Silva FR, Vettore AL, Kemper EL, Leite A, Arruda P. Fastidian gum: the Xylella fastidiosa exopolysaccharide possibly involved in bacterial pathogenicity. FEMS Microbiol Lett 2001; 203:165-71. [PMID: 11583843 DOI: 10.1111/j.1574-6968.2001.tb10836.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The Gram-negative bacterium Xylella fastidiosa was the first plant pathogen to be completely sequenced. This species causes several economically important plant diseases, including citrus variegated chlorosis (CVC). Analysis of the genomic sequence of X. fastidiosa revealed a 12 kb DNA fragment containing an operon closely related to the gum operon of Xanthomonas campestris. The presence of all genes involved in the synthesis of sugar precursors, existence of exopolysaccharide (EPS) production regulators in the genome, and the absence of three of the X. campestris gum genes suggested that X. fastidiosa is able to synthesize an EPS different from that of xanthan gum. This novel EPS probably consists of polymerized tetrasaccharide repeating units assembled by the sequential addition of glucose-1-phosphate, glucose, mannose and glucuronic acid on a polyprenol phosphate carrier.
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Affiliation(s)
- F R da Silva
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6010, CEP 13083-970, Campinas, São Paulo, Brazil
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8
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Borecký J, Maia IG, Costa AD, Jezek P, Chaimovich H, de Andrade PB, Vercesi AE, Arruda P. Functional reconstitution of Arabidopsis thaliana plant uncoupling mitochondrial protein (AtPUMP1) expressed in Escherichia coli. FEBS Lett 2001; 505:240-4. [PMID: 11566183 DOI: 10.1016/s0014-5793(01)02835-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Arabidopsis thaliana uncoupling protein (UCP) gene was expressed in Escherichia coli and isolated protein reconstituted into liposomes. Linoleic acid-induced H+ fluxes were sensitive to purine nucleotide inhibition with an apparent K(i) (in mM) of 0.8 (GDP), 0.85 (ATP), 0.98 (GTP), and 1.41 (ADP); the inhibition was pH-dependent. Kinetics of AtPUMP1-mediated H+ fluxes were determined for lauric, myristic, palmitic, oleic, linoleic, and linolenic acids. Properties of recombinant AtPUMP1 indicate that it represents a plant counterpart of animal UCP2 or UCP3. This work brings the functional and genetic approaches together for the first time, providing strong support that AtPUMP1 is truly an UCP.
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Affiliation(s)
- J Borecký
- Department of Membrane Transport Biophysics, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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9
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Capella AN, Menossi M, Arruda P, Benedetti CE. COI1 affects myrosinase activity and controls the expression of two flower-specific myrosinase-binding protein homologues in Arabidopsis. Planta 2001; 213:691-699. [PMID: 11678272 DOI: 10.1007/s004250100548] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two cDNA clones homologous to myrosinase-binding proteins (MBPs) were identified by differential display in Arabidopsis thaliana (L.) Heynh. The cDNAs (MBP1 and MBP2) correspond to two open-reading frames found in a gene cluster of seven putative MBP genes located on chromosome 1. The predicted proteins MBP1 and MBP2 are similar to lectins and plant aggregating factors. In addition. MBP2 contains a region of high content of proline and alanine residues, commonly found in arabinogalactan proteins and hydroxyproline-rich glycoproteins. Transcripts corresponding to MBP1 and MBP2 genes are exclusively and abundantly expressed in flowers but are not detected in male-sterile flowers of coi1 plants, insensitive to jasmonic acid. Northern analysis and in situ hybridization revealed that MBP mRNAs are present in higher levels in immature flowers and are localized in several floral organs, including the ovary, ovules, style, anthers and filament. Transcripts of the Arabidopsis myrosinase gene TGG1 show a pattern of expression similar to that observed for the MBP genes during flower development; however, they are also abundant in green tissues and are only partially affected by COI1. Crude preparations of soluble proteins from leaf and flower extracts of wild-type Arabidopsis showed myrosinase activity when sinigrin was used as substrate. In contrast, coi1 plants showed significantly reduced myrosinase activities in both leaves and flowers. The results show that COI1 controls MBP expression in flowers and significantly affects the expression and activity of myrosinase in Arabidopsis.
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Affiliation(s)
- A N Capella
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil
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10
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Abstract
Evidence has been provided that the plant uncoupling proteins (pUCP) play basic physiological roles similar to the other uncoupling protein subfamily members (mammalian UCP1,2,3,4 and BMCP) and are effective in the situations of slight uncoupling that leads to: (1) accelerated respiration and metabolic rates that are beneficial to plant growth and development; (2) decreased formation of reactive oxygen species in mitochondria; and, (3) mild thermogenesis, inevitably accompanying the previous two phenomena. Hypothetically, specific physiological roles of pUCP such as cut off of ATP synthesis could be manifested in connection with climacteric respiratory rise during fruit ripening, seed dormancy, and plant senescence. pUCP might also facilitate growth under low temperatures, e.g., during seed germination or in roots. The existence of these specific roles is suggested by the immunochemical and functional localization of pUCP in mitochondria of fruits, seeds and roots of various plant species.
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Affiliation(s)
- P Jezek
- Department of Membrane Transport Biophysics, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague
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11
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Abstract
Uncoupling proteins (UCPs) belong to a distinct cluster of the mitochondrial anion carrier family. Up to five different uncoupling protein types were found in mitochondria of mammals and plants, and recently in fishes, fungi and protozoa. They exhibit a significantly conserved structure with several motifs specific to either the whole cluster or protein type. Uncoupling proteins, as well as the whole mitochondrial anion carrier gene family, probably emerged in evolution before the separation of animal, fungi, and plant kingdoms and originate from an anion/nucleotide or anion/anion transporter ancestor. Mammalian UCP1, UCP2, UCP3, and plant uncoupling proteins pUCP1 and pUCP2 are similar and seem to form one subgroup, whereas UCP4 and BMCP1 belong to a different group. Molecular, biochemical, and phylogenic data suggest that UCP2 could be considered as an UCP-prototype. UCP1 plays its biological role mainly in the non-shivering thermogenesis while the role of the other types is unknown. However, hypotheses have suggested that they are involved in the general balance of basic energy expenditure, protection from reactive oxygen species, and, in plants, in fruit ripening and seed ontogeny.
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Affiliation(s)
- J Borecký
- Department of Membrane Transport Biophysics. Institute of Physiology, Academy of Sciences of the Czech Republic, Prague
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12
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Abstract
Lysine has long been recognized as an essential amino acid for humans and the lack or low supply of this compound in the diet may lead to mental and physical handicaps. Since lysine is severely restricted in cereals, the most important staple food in the world, the understanding of its biological roles must be a major concern. Here we show that lysine is an important precursor for de novo synthesis of glutamate, the most significant excitatory neurotransmitter in the mammalian central nervous system. We also show that the synthesis of glutamate from lysine, which is carried out by the saccharopine pathway, is likely to take place in neurons.
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Affiliation(s)
- F Papes
- Centro de Biologia Molecular e Eugenharia Genetica, Universidade Estadual de Campinas, SP, Brazil
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13
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Lessinger AC, Martins Junqueira AC, Lemos TA, Kemper EL, da Silva FR, Vettore AL, Arruda P, Azeredo-Espin AM. The mitochondrial genome of the primary screwworm fly Cochliomyia hominivorax (Diptera: Calliphoridae). Insect Mol Biol 2000; 9:521-529. [PMID: 11029671 DOI: 10.1046/j.1365-2583.2000.00215.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The complete sequence of the mitochondrial genome of the screwworm Cochliomyia hominivorax was determined. This genome is 16,022 bp in size and corresponds to a typical Brachycera mtDNA. A Serine start codon for COI and incomplete termination codons for COII, NADH 5 and NADH 4 genes were described. The nucleotide composition of C. hominivorax mtDNA is 77% AT-rich, reflected in the predominance of AT-rich codons in protein-coding genes. Non-optimal codon usage was commonly observed in C. hominivorax mitochondrial genes. Phylogenetic analysis distributed the Acalypterate species as a monophyletic group and assembled the C. hominivorax (Calyptratae) and the Acalyptratae in a typical Brachycera cluster. The identification of diagnostic restriction sites on the sequenced mitochondrial genome and the correlation with previous RFLP analysis are discussed.
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Affiliation(s)
- A C Lessinger
- Laboratório de Genética Animal,Laboratório Genoma, Instituto de Biologia, Universidade Estadual de Campinas - UNICAMP, Campinas, São Paulo, Brazil
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14
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Costa CL, Arruda P, Benedetti CE. An Arabidopsis gene induced by wounding functionally homologous to flavoprotein oxidoreductases. Plant Mol Biol 2000; 44:61-71. [PMID: 11094980 DOI: 10.1023/a:1006464822434] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The regulation of genes in response to wounding is mediated in part by the octadecanoids 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA) and its methyl ester methyl jasmonate (MeJA). We identified, by differential display, an Arabidopsis gene (OPR3) induced after wounding. OPR3 is homologous to members of the flavin mononucleotide (FMN) binding proteins, including the old yellow enzyme (OYE) from yeast and 12-oxophytodienoate-10,11-reductase (OPR) from Arabidopsis. Transcripts of OPR3 rapidly accumulated in leaves after wounding and MeJA treatment, but they were detected in various tissues of unwounded plants at relatively low levels. Expression of the OPR3 gene was significantly reduced in wounded leaves of the coil mutant, indicating partial dependence on jasmonate perception for full induction of the gene. The recombinant protein of OPR3 cross-reacted with an antiserum raised against the OYE protein, and showed oxidation of beta-NADPH when OPDA or 15-deoxy-delta(12,14) prostaglandin J2 (PGJ2), an analogue of OPDA, was used as substrate. Beta-NADPH oxidation was not observed when MeJA, which lacks the double bond in the ketone ring, was used as substrate. The recombinant OPR3 protein also showed beta-NADPH oxidation activity in the presence of cyclohexenone, but not cyclohexanone, suggesting that the enzyme has specificity to cleavage of olefinic bonds in cyclic enones. The results show that the OPR3 gene product represents a new OPR of Arabidopsis induced after wounding.
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MESH Headings
- Acetates/pharmacology
- Amino Acid Sequence
- Arabidopsis/genetics
- Arabidopsis Proteins
- Blotting, Northern
- Cyclopentanes/pharmacology
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Flavoproteins
- Gene Expression Regulation, Plant/drug effects
- Genes, Plant/genetics
- Kinetics
- Molecular Sequence Data
- NADH, NADPH Oxidoreductases/genetics
- NADH, NADPH Oxidoreductases/metabolism
- NADP/metabolism
- Oxidation-Reduction
- Oxidoreductases/genetics
- Oxylipins
- Plant Proteins
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Stress, Mechanical
- Substrate Specificity
- Tissue Distribution
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Affiliation(s)
- C L Costa
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil
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15
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Abstract
Lysine is an essential amino acid for mammals but its concentration in cereals, one of our main food sources, is low. Research over the past 40 years has unraveled many biochemical and molecular details of the aspartic acid pathway, which is the main route of lysine biosynthesis in plants. However, genetic manipulation of this pathway has not been successful at producing high-lysine seeds. This is because lysine, instead of being accumulated, is degraded via the saccharopine pathway. Recent work has increased our knowledge of this pathway, including both the enzymes involved and their regulation.
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Affiliation(s)
- P Arruda
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil.
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16
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Abstract
Lysine is an essential amino acid for mammals but its concentration in cereals, one of our main food sources, is low. Research over the past 40 years has unraveled many biochemical and molecular details of the aspartic acid pathway, which is the main route of lysine biosynthesis in plants. However, genetic manipulation of this pathway has not been successful at producing high-lysine seeds. This is because lysine, instead of being accumulated, is degraded via the saccharopine pathway. Recent work has increased our knowledge of this pathway, including both the enzymes involved and their regulation.
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Affiliation(s)
- P Arruda
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil.
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17
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Abstract
A previously uncharacterized virus was reported in southeast Brazil causing a yellowing leaf disease in sugarcane. The virus, termed sugarcane yellow leaf virus (ScYLV), shares features typical of the luteoviruses. To start the molecular characterization of ScYLV, the nucleotide sequence of the coat protein (CP), 17 kDa protein and C-terminus of the RNA-dependent RNA polymerase coding regions was determined from an RT-PCR amplification product. Comparisons showed that the deduced amino acid sequences share a considerable degree of identity and similarity with corresponding sequences of known luteoviruses, thus clearly establishing ScYLV as a member of the family Luteoviridae. The authenticity of the CP open reading frame was confirmed by its expression in Escherichia coli. The recombinant CP positively reacted in immunoblot assays with polyclonal antibodies raised against native ScYLV. Furthermore, phylogenetic analyses also suggest that the 5' and 3' coding blocks of the ScYLV genome possess different taxonomic affinities within the Luteoviridae family, as does also the genome of soybean dwarf virus.
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Affiliation(s)
- I G Maia
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil
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18
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Simpson AJ, Reinach FC, Arruda P, Abreu FA, Acencio M, Alvarenga R, Alves LM, Araya JE, Baia GS, Baptista CS, Barros MH, Bonaccorsi ED, Bordin S, Bové JM, Briones MR, Bueno MR, Camargo AA, Camargo LE, Carraro DM, Carrer H, Colauto NB, Colombo C, Costa FF, Costa MC, Costa-Neto CM, Coutinho LL, Cristofani M, Dias-Neto E, Docena C, El-Dorry H, Facincani AP, Ferreira AJ, Ferreira VC, Ferro JA, Fraga JS, França SC, Franco MC, Frohme M, Furlan LR, Garnier M, Goldman GH, Goldman MH, Gomes SL, Gruber A, Ho PL, Hoheisel JD, Junqueira ML, Kemper EL, Kitajima JP, Krieger JE, Kuramae EE, Laigret F, Lambais MR, Leite LC, Lemos EG, Lemos MV, Lopes SA, Lopes CR, Machado JA, Machado MA, Madeira AM, Madeira HM, Marino CL, Marques MV, Martins EA, Martins EM, Matsukuma AY, Menck CF, Miracca EC, Miyaki CY, Monteriro-Vitorello CB, Moon DH, Nagai MA, Nascimento AL, Netto LE, Nhani A, Nobrega FG, Nunes LR, Oliveira MA, de Oliveira MC, de Oliveira RC, Palmieri DA, Paris A, Peixoto BR, Pereira GA, Pereira HA, Pesquero JB, Quaggio RB, Roberto PG, Rodrigues V, de M Rosa AJ, de Rosa VE, de Sá RG, Santelli RV, Sawasaki HE, da Silva AC, da Silva AM, da Silva FR, da Silva WA, da Silveira JF, Silvestri ML, Siqueira WJ, de Souza AA, de Souza AP, Terenzi MF, Truffi D, Tsai SM, Tsuhako MH, Vallada H, Van Sluys MA, Verjovski-Almeida S, Vettore AL, Zago MA, Zatz M, Meidanis J, Setubal JC. The genome sequence of the plant pathogen Xylella fastidiosa. The Xylella fastidiosa Consortium of the Organization for Nucleotide Sequencing and Analysis. Nature 2000; 406:151-9. [PMID: 10910347 DOI: 10.1038/35018003] [Citation(s) in RCA: 538] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Xylella fastidiosa is a fastidious, xylem-limited bacterium that causes a range of economically important plant diseases. Here we report the complete genome sequence of X. fastidiosa clone 9a5c, which causes citrus variegated chlorosis--a serious disease of orange trees. The genome comprises a 52.7% GC-rich 2,679,305-base-pair (bp) circular chromosome and two plasmids of 51,158 bp and 1,285 bp. We can assign putative functions to 47% of the 2,904 predicted coding regions. Efficient metabolic functions are predicted, with sugars as the principal energy and carbon source, supporting existence in the nutrient-poor xylem sap. The mechanisms associated with pathogenicity and virulence involve toxins, antibiotics and ion sequestration systems, as well as bacterium-bacterium and bacterium-host interactions mediated by a range of proteins. Orthologues of some of these proteins have only been identified in animal and human pathogens; their presence in X. fastidiosa indicates that the molecular basis for bacterial pathogenicity is both conserved and independent of host. At least 83 genes are bacteriophage-derived and include virulence-associated genes from other bacteria, providing direct evidence of phage-mediated horizontal gene transfer.
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Affiliation(s)
- A J Simpson
- Instituto Ludwig de Pesquisa sobre o Câncer, São Paulo, SP, Brazil
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19
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Menossi M, Cremonese N, Maron LG, Arruda P. Making colony PCR easier by adding gel-loading buffer to the amplification reaction. Biotechniques 2000; 28:424, 426. [PMID: 10723552 DOI: 10.2144/00283bm06] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- M Menossi
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil.
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20
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Urcuqui-Inchima S, Maia IG, Arruda P, Haenni AL, Bernardi F. Deletion mapping of the potyviral helper component-proteinase reveals two regions involved in RNA binding. Virology 2000; 268:104-11. [PMID: 10683332 DOI: 10.1006/viro.1999.0156] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Potyvirus helper component-proteinase (HC-Pro) binds nonspecifically to single-stranded nucleic acids with a preference for RNA. To delineate the regions of the protein responsible for RNA binding, deletions were introduced into the full-length Potato potyvirus Y HC-Pro gene carried by an Escherichia coli expression vector. The corresponding proteins were expressed as fusions with the maltose-binding protein, purified, and assayed for their RNA-binding capacity. The results obtained by UV cross-linking and Northwestern blot assays demonstrated that the N- and C-terminal regions of HC-Pro are dispensable for RNA binding. They also revealed the presence of two independent RNA-binding domains (designated A and B) located in the central part of HC-Pro. Domain B appears to contain a ribonucleoprotein (RNP) motif typical of a large family of RNA-binding proteins involved in several cellular processes. The possibility that domain B consists of an RNP domain is discussed and suggests that HC-Pro could constitute the first example of a plant viral protein belonging to the RNP-containing family of proteins.
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Affiliation(s)
- S Urcuqui-Inchima
- Institut Jacques Monod, 2 place Jussieu-Tour 43, Paris Cedex 05, 75251, France
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21
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Papes F, Kemper EL, Cord-Neto G, Langone F, Arruda P. Lysine degradation through the saccharopine pathway in mammals: involvement of both bifunctional and monofunctional lysine-degrading enzymes in mouse. Biochem J 1999; 344 Pt 2:555-563. [PMID: 10567240 DOI: 10.1042/0264-6021:3440555] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Lysine-oxoglutarate reductase and saccharopine dehydrogenase are enzymic activities that catalyse the first two steps of lysine degradation through the saccharopine pathway in upper eukaryotes. This paper describes the isolation and characterization of a cDNA clone encoding a bifunctional enzyme bearing domains corresponding to these two enzymic activities. We partly purified those activities from mouse liver and showed for the first time that both a bifunctional lysine-oxoglutarate reductase/saccharopine dehydrogenase and a monofunctional saccharopine dehydrogenase are likely to be present in this organ. Northern analyses indicate the existence of two mRNA species in liver and kidney. The longest molecule, 3.4 kb in size, corresponds to the isolated cDNA and encodes the bifunctional enzyme. The 2.4 kb short transcript probably codes for the monofunctional dehydrogenase. Sequence analyses show that the bifunctional enzyme is likely to be a mitochondrial protein. Furthermore, enzymic and expression analyses suggest that lysine-oxoglutarate reductase/saccharopine dehydrogenase levels increase in livers of mice under starvation. Lysine-injected mice also show an increase in lysine-oxoglutarate reductase and saccharopine dehydrogenase levels.
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Affiliation(s)
- F Papes
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, CEP 13083-970, SP, Brasil
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22
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Dante RA, Neto GC, Leite A, Yunes JA, Arruda P. The DapA gene encoding the lysine biosynthetic enzyme dihydrodipicolinate synthase from Coix lacryma-jobi: cloning, characterization, and expression analysis. Plant Mol Biol 1999; 41:551-561. [PMID: 10608664 DOI: 10.1023/a:1006367116073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Dihydrodipicolinate synthase (DHPS) is the main enzyme of a specific branch of the aspartate pathway leading to lysine biosynthesis in higher plants. We have cloned and characterized the DHPS-encoding Dap)A gene from the maize-related grass Coix lacryiana-jobi. The DapA open reading frame is interrupted by two introns and encodes the 326 amino acid-long Coix DHPS protein, which is 95% identical to the maize DHPS protein. Coix DNA gel blot analysis with maize DHPS cDNA as a probe showed a single strongly hybridizing band along with faint bands. RNA gel blot analysis showed that DHPS transcripts are present in coleoptiles, embryos, endosperms, and roots but are almost undetectable in blades of young leaves of both Coix and maize. The 5'-flanking region of the DapA gene contains a TGACTC GCN4-like element located 372 bp upstream the putative translation start codon. Steady-state levels of DHPS mRNA were slightly reduced in the endosperms and embryos of the maize lysine-rich opaque2 mutants when compared with those in normal kernels. Selective binding assay with the maize Opaque2 protein (O2) showed that the GCN4-like element is not an O2 binding site, suggesting that the DHPS gene is not under the control of O2.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Cloning, Molecular
- DNA, Plant/chemistry
- DNA, Plant/genetics
- DNA, Plant/isolation & purification
- DNA-Binding Proteins/metabolism
- Gene Dosage
- Gene Expression Regulation, Developmental/radiation effects
- Gene Expression Regulation, Enzymologic/radiation effects
- Gene Expression Regulation, Plant/radiation effects
- Genes/genetics
- Hydro-Lyases/genetics
- Hydro-Lyases/metabolism
- Light
- Lysine/biosynthesis
- Molecular Sequence Data
- Plant Proteins
- Poaceae/enzymology
- Poaceae/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
- Transcription Factors/metabolism
- Zea mays/genetics
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Affiliation(s)
- R A Dante
- Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, SP, Brazil
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23
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Costa AD, Nantes IL, Jezek P, Leite A, Arruda P, Vercesi AE. Plant uncoupling mitochondrial protein activity in mitochondria isolated from tomatoes at different stages of ripening. J Bioenerg Biomembr 1999; 31:527-33. [PMID: 10653480 DOI: 10.1023/a:1005408809619] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In the present study we have observed a higher state of coupling in respiring mitochondria isolated from green as compared to red tomatoes (Lycopersicon esculentum, Mill.). Green tomato mitochondria produced a membrane potential (deltapsi) high enough to phosphorylate ADP, whereas in red tomato mitochondria, BSA and ATP were required to restore deltapsi to the level of that obtained with green tomato mitochondria. This supports the notion that such uncoupling in red tomato mitochondria is mediated by a plant uncoupling mitochondrial protein (PUMP; cf. Vercesi et al., 1995). Nevertheless, mitochondria from both green and red tomatoes exhibited an ATP-sensitive linoleic acid (LA)-induced deltapsi decrease providing evidence that PUMP is also present in green tomatoes. Indeed, proteoliposomes containing reconstituted green or red tomato PUMP showed LA uniport and LA-induced H+ transport. It is suggested that the higher concentration of free fatty acids (PUMP substrates) in red tomatoes could explain the lower coupling state in mitochondria isolated from these fruits.
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Affiliation(s)
- A D Costa
- Departamento de Patologia Clínica (NMCE), Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brazil
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24
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Kemper EL, Neto GC, Papes F, Moraes KC, Leite A, Arruda P. The role of opaque2 in the control of lysine-degrading activities in developing maize endosperm. Plant Cell 1999; 11:1981-94. [PMID: 10521527 PMCID: PMC144114 DOI: 10.1105/tpc.11.10.1981] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We have isolated a cDNA clone, designated ZLKRSDH, encoding the bifunctional enzyme lysine-ketoglutarate reductase/saccharopine dehydrogenase (LKR/SDH) from maize. The predicted polypeptide has an N-terminal LKR domain and a C-terminal SDH domain that are similar to the yeast LYS1 and LYS9 monofunctional proteins, respectively. The maize LKR/SDH protein is located in the cytoplasm of subaleurone endosperm cell layers. Transcripts and polypeptides as well as enzyme activities showed an upregulation and downregulation during endosperm development. The developmental expression of ZLKRSDH was examined in normal and opaque2 seeds. In the mutant endosperm, mRNA levels were reduced by >90%, with concomitant reductions in polypeptide levels and LKR/SDH activity. These results suggest that lysine levels in the endosperm are likely to be controlled at the transcriptional level by the Opaque2 transcription factor.
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Affiliation(s)
- E L Kemper
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil
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25
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Abstract
In this communication, we show that the plant uncoupling mitochondrial protein (PUMP) present in potato tuber mitochondria is induced by aging at 28 degrees C and that this induction is strongly stimulated when the potato tubers are stored at low temperature (4 degrees C). PUMP activity was detected by the degree of linoleic acid (LA)-induced ATP-sensitive mitochondrial uncoupling measured as a function of the decrease in membrane potential (delta psi). The PUMP content was evaluated by immunoblot analysis using polyclonal antibodies raised against potato PUMP that specifically detected a 32 kDa band. In agreement with the effect of LA on delta psi, the content of the 32 kDa band increased during storage and was stimulated by low temperature. These results support the proposed role of PUMP in plant thermogenesis and possibly in fruit ripening and senescence.
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Affiliation(s)
- I L Nantes
- Departamento de Patologia Clínica, NMCE, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brazil
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26
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Sibov ST, Gaspar M, Silva MJ, Ottoboni LMM, Arruda P, Souza AP. Two genes control aluminum tolerance in maize: Genetic and molecular mapping analyses. Genome 1999. [DOI: 10.1139/g98-146] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have identified two loci linked to aluminum (Al) tolerance in the maize inbred line Cat-100-6 by means of restriction fragment length polymorphism (RFLP) and bulked segregant analysis (BSA). A segregating population F2 was obtained from a cross between Cat-100-6 (Al tolerant) × S1587-17 (Al sensitive) parents. Subsequently two DNA bulks of individuals, displaying a contrasting Al tolerance trait were generated from F2. From a total of 158 markers used, 30 markers were identified showing polymorphism between parents and bulks. The segregation results derived from the hybridization from these 30 markers and 56 individuals from F2 revealed 10 markers cosegregating with the Al tolerance which were located in two linkage groups. The linkage groups were composed of 6 and 4 markers, and they were mapped on the short arm of chromosomes 6 and 10, respectively. From these observations, we deduce that two loci are involved in this trait in Cat-100-6 line. QGENE software was used to study the correlation between these two loci and the trait for aluminum tolerance. The results indicate that the locus on chromosome 10 has the stronger effect, and it is responsible for the major part of the variability of the trait.Key words: maize, aluminum tolerance, molecular mapping, somaclonal variation.
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27
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Almeida AM, Jarmuszkiewicz W, Khomsi H, Arruda P, Vercesi AE, Sluse FE. Cyanide-resistant, ATP-synthesis-sustained, and uncoupling-protein-sustained respiration during postharvest ripening of tomato fruit. Plant Physiol 1999; 119:1323-30. [PMID: 10198091 PMCID: PMC32017 DOI: 10.1104/pp.119.4.1323] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/1998] [Accepted: 12/21/1998] [Indexed: 05/20/2023]
Abstract
Tomato (Lycopersicon esculentum) mitochondria contain both alternative oxidase (AOX) and uncoupling protein as energy-dissipating systems that can decrease the efficiency of oxidative phosphorylation. We followed the cyanide (CN)-resistant, ATP-synthesis-sustained, and uncoupling-protein-sustained respiration of isolated mitochondria, as well as the immunologically detectable levels of uncoupling protein and AOX, during tomato fruit ripening from the mature green stage to the red stage. The AOX protein level and CN-resistant respiration of isolated mitochondria decreased with ripening from the green to the red stage. The ATP-synthesis-sustained respiration followed the same behavior. In contrast, the level of uncoupling protein and the total uncoupling-protein-sustained respiration of isolated mitochondria decreased from only the yellow stage on. We observed an acute inhibition of the CN-resistant respiration by linoleic acid in the micromolar range. These results suggest that the two energy-dissipating systems could have different roles during the ripening process.
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Affiliation(s)
- AM Almeida
- Departamento de Patologia Clinica, Faculdade de Cieancias Medicas (A.M.A., A.E.V.)
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28
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de Souza Filho GA, da Silva MJ, Vettore AL, Yunes JA, Leite A, Arruda P, Ottoboni LM. Identification of a DNA-binding factor that recognizes an alpha-coixin promoter and interacts with a Coix Opaque-2 like protein. Plant Mol Biol 1999; 39:95-104. [PMID: 10080712 DOI: 10.1023/a:1006150728210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Transient expression and electrophoretic mobility shift assay were used to investigate the cis elements and the DNA-binding proteins involved in the regulation of expression of a 22 kDa zein-like alpha-coixin gene. A set of unidirectional deletions was generated in a 962 bp fragment of the alpha-coixin promoter that had been previously fused to the reporter gene GUS. The constructs were assayed by transient expression in immature maize endosperm. There was no significant decrease in GUS activity as deletions progressed from -1084 to -238. However, deletion from -238 to -158, which partially deleted the O2c box, resulted in a dramatic decrease in GUS activity emphasizing the importance of the O2 box in the quantitative expression of the gene. The -238 promoter fragment interacted with Coix endosperm nuclear proteins to form 5 DNA-protein complexes, C1-C5, as detected by EMSA. The same retarded complexes were observed when the -158 promoter fragment was used in the binding reactions. Reactions with nuclear extracts isolated from Coix endosperms harvested from 6 to 35 days after pollination revealed that the 5 DNA-protein complexes that interact with the alpha-coixin promoter are differentially assembled during seed development. Deletion analysis carried out on the -238/ATG promoter fragment showed that a 35 bp region from -86 to -51 is essential for the formation of the complexes observed. When nuclear extracts were incubated with an antiserum raised against the maize Opaque-2 protein, the formation of 4 complexes, C1, C3, C4 and C5, was prevented indicating that an Opaque-2 like protein participates in the formation of those complexes. Complex C2 was not affected by the addition of the O2 antibody, suggesting the existence of a novel nuclear factor, CBF1, that binds to the promoter and makes protein-protein associations with other proteins present in Coix endosperm nuclei.
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Affiliation(s)
- G A de Souza Filho
- Centro de Biologia Molecular e Engenharia Genética, Instituto de Biologia, Universidade Estadual de Campinas, SP, Brazil
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29
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Yunes JA, Vettore AL, da Silva MJ, Leite A, Arruda P. Cooperative DNA binding and sequence discrimination by the Opaque2 bZIP factor. Plant Cell 1998; 10:1941-55. [PMID: 9811800 PMCID: PMC143964 DOI: 10.1105/tpc.10.11.1941] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The maize Opaque2 (O2) protein is a basic leucine zipper transcription factor that controls the expression of distinct classes of endosperm genes through the recognition of different cis-acting elements in their promoters. The O2 target region in the promoter of the alpha-coixin gene was analyzed in detail and shown to comprise two closely adjacent binding sites, named O2u and O2d, which are related in sequence to the GCN4 binding site. Quantitative DNase footprint analysis indicated that O2 binding to alpha-coixin target sites is best described by a cooperative model. Transient expression assays showed that the two adjacent sites act synergistically. This synergy is mediated in part by cooperative DNA binding. In tobacco protoplasts, O2 binding at the O2u site is more important for enhancer activity than is binding at the O2d site, suggesting that the architecture of the O2-DNA complex is important for interaction with the transcriptional machinery.
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Affiliation(s)
- J A Yunes
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil
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30
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Abstract
A cDNA clone (AtPUMP) encoding a plant uncoupling mitochondrial protein was isolated from Arabidopsis thaliana. The cDNA contains an open reading frame of 921 nucleotides encoding 306 amino acids (predicted molecular weight 32,708). The predicted polypeptide is 81% identical and 89% similar to the potato UCP-like protein, and includes an energy transfer protein motif common to mitochondrial transporters. The AtPUMP gene exists as a single copy in the Arabidopsis genome. The corresponding transcript was expressed in all tissues and was strongly induced by cold treatment. We suggest that the putative AtPUMP protein may play a role in heat-requiring physiological events in Arabidopsis.
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Affiliation(s)
- I G Maia
- Centro de Biologia Molecular e Engenharia Genética, C.P. 6109, Universidade Estadual de Campinas, SP, Brazil
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31
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Jezek P, Engstová H, Zácková M, Vercesi AE, Costa AD, Arruda P, Garlid KD. Fatty acid cycling mechanism and mitochondrial uncoupling proteins. Biochim Biophys Acta 1998; 1365:319-27. [PMID: 9693744 DOI: 10.1016/s0005-2728(98)00084-x] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We hypothesize that fatty acid-induced uncoupling serves in bioenergetic systems to set the optimum efficiency and tune the degree of coupling of oxidative phosphorylation. Uncoupling results from fatty acid cycling, enabled by several phylogenetically specialized proteins and, to a lesser extent, by other mitochondrial carriers. It is suggested that the regulated uncoupling in mammalian mitochondria is provided by uncoupling proteins UCP-1, UCP-2 and UCP-3, whereas in plant mitochondria by PUMP and StUCP, all belonging to the gene family of mitochondrial carriers. UCP-1, and hypothetically UCP-3, serve mostly to provide nonshivering thermogenesis in brown adipose tissue and skeletal muscle, respectively. Fatty acid cycling was documented for UCP-1, PUMP and ADP/ATP carrier, and is predicted also for UCP-2 and UCP-3. UCP-1 mediates a purine nucleotide-sensitive uniport of monovalent unipolar anions, including anionic fatty acids. The return of protonated fatty acid leads to H+ uniport and uncoupling. UCP-2 is probably involved in the regulation of body weight and energy balance, in fever, and defense against generation of reactive oxygen species. PUMP has been discovered in potato tubers and immunologically detected in fruits and corn, whereas StUCP has been cloned and sequenced froma a potato gene library. PUMP is supposed to act in the termination of synthetic processes in mature fruits and during the climacteric respiratory rise.
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Affiliation(s)
- P Jezek
- Department of Membrane Transport Biophysics, Academy of Sciences of the Czech Republic, Prague.
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32
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Kemper EL, Cord-Neto G, Capella AN, Gonçalves-Butruile M, Azevedo RA, Arruda P. Structure and regulation of the bifunctional enzyme lysine-oxoglutarate reductase-saccharopine dehydrogenase in maize. Eur J Biochem 1998; 253:720-9. [PMID: 9654071 DOI: 10.1046/j.1432-1327.1998.2530720.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The lysine-oxoglutarate reductase (LOR) domain of the bifunctional enzyme lysine-oxoglutarate reductase-saccharopine dehydrogenase (LOR/SDH) from maize endosperm was shown to be activated by Ca2+, high salt concentration, organic solvents and Mg2+. The Ca2+-dependent enhancement of LOR activity was inhibited by the calmodulin antagonists N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W7) and calmidazolium. Limited proteolysis was used to assess the structure/function relationship of the enzyme. Digestion with elastase separated the bifunctional 125-kDa polypeptide into two polypeptides of 65 kDa and 57 kDa, containing the functional domains of LOR and SDH, respectively. Proteolysis did not affect SDH activity, while LOR showed a time-dependent and protease-concentration-dependent inactivation followed by reactivation. Prolonged digestion or increasing amounts of elastase produced a complex pattern of limit polypeptides derived from additional cleavage sites within the 65-kDa (LOR) and 57-kDa (SDH) domains. The SDH-containing polypeptides inhibited the enzymatic activity of LOR-containing polypeptides. When separated from the SDH domain by limited proteolysis and ion-exchange chromatography, the LOR domain retained its Ca2+ activation property, but was no longer activated by high salt concentrations. These results suggest that the LOR activity of the native enzyme is normally inhibited such that after modulation, the enzyme undergoes a conformational alteration to expose the catalytic domain for substrate binding.
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Affiliation(s)
- E L Kemper
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brasil
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33
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Benedetti CE, Costa CL, Turcinelli SR, Arruda P. Differential expression of a novel gene in response to coronatine, methyl jasmonate, and wounding in the Coi1 mutant of Arabidopsis. Plant Physiol 1998; 116:1037-42. [PMID: 9501136 PMCID: PMC35073 DOI: 10.1104/pp.116.3.1037] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Coronatine is a phytotoxin produced by some plant-pathogenic bacteria. It has been shown that coronatine mimics the action of methyl jasmonate (MeJA) in plants. MeJA is a plant-signaling molecule involved in stress responses such as wounding and pathogen attack. In Arabidopsis thaliana, MeJA is essential for pollen grain development. The coi1 (for coronatine-insensitive) mutant of Arabidopsis, which is insensitive to coronatine and MeJA, produces sterile male flowers and shows an altered response to wounding. When the differential display technique was used, a message that was rapidly induced by coronatine in wild-type plants but not in coi1 was identified and the corresponding cDNA was cloned. The coronatine-induced gene ATHCOR1 (for A. thaliana coronatine-induced) is expressed in seedlings, mature leaves, flowers, and siliques but was not detected in roots. The expression of this gene was dramatically reduced in coi1 plants, indicating that COI1 affects its expression. ATHCOR1 was rapidly induced by MeJA and wounding in wild-type plants. The sequence of ATHCOR1 shows no strong homology to known proteins. However, the predicted polypeptide contains a conserved amino acid sequence present in several bacterial, animal, and plant hydrolases and includes a potential ATP/GTP-binding-site motif (P-loop).
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Affiliation(s)
- C E Benedetti
- Centro de Biologia Molecular e Engenharia Genética-Universidade Estadual de Campinas, Campinas, São Paulo, Brazil.
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34
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Vettore AL, Yunes JA, Cord Neto G, da Silva MJ, Arruda P, Leite A. The molecular and functional characterization of an Opaque2 homologue gene from Coix and a new classification of plant bZIP proteins. Plant Mol Biol 1998; 36:249-263. [PMID: 9484437 DOI: 10.1023/a:1005995806897] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The seed storage proteins of Coix, sorghum and maize are codified by homologous genes which are coordinately expressed in the endosperm in a temporal-specific fashion. Opaque2 (O2), a bZIP protein originally isolated from maize, has been described as a transcription activator of alpha- and beta-prolamin genes. The isolation and characterization of cDNA and genomic clones encoding the Opaque2 homologue from Coix are reported here. The coding region of the Coix O2 gene is interrupted by five introns and codifies a polypeptide of 408 amino acids. Comparison of the deduced amino acid sequence with two different sequences of maize O2 protein showed that the Coix O2 protein is similar to the maize O2 isolated from W22 maize inbred line. The Coix O2 protein has the same binding specificity and expression pattern of the maize O2. The O2 proteins together with OHP1, OsBZIPPA, SPA, CPRF2 and RITA1 were assigned to one of the five bZIP plant families in an updated classification of plant bZIP according to bZIP domain similarity.
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Affiliation(s)
- A L Vettore
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil
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35
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Abstract
The essential amino acids lysine, threonine, methionine and isoleucine are synthesised in higher plants via a common pathway starting with aspartate. The regulation of the pathway is discussed in detail, and the properties of the key enzymes described. Recent data obtained from studies of regulation at the gene level and information derived from mutant and transgenic plants are also discussed. The herbicide target enzyme acetohydroxyacid synthase involved in the synthesis of the branched chain amino acids is reviewed.
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Affiliation(s)
- R A Azevedo
- Departamento de Genética, Universidade de São Paulo, Piracicaba, SP, Brasil
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36
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Moon DH, Ottoboni LMM, Souza AP, Sibov ST, Gaspar M, Arruda P. Somaclonal-variation-induced aluminum-sensitive mutant from an aluminum-inbred maize tolerant line. Plant Cell Rep 1997; 16:686-691. [PMID: 30727619 DOI: 10.1007/s002990050302] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Somaclonal-variation-induced multiple mutations were observed in a progeny of the S1587 plant, regenerated from type I calli of the aluminum-tolerant inbred maize line Cat-100-6. After five generations of self-pollination, 14 progeny families of the S1587 somaclone were found to show aluminum toxicity symptoms with altered root tip morphology and reduced primary root growth. The most sensitive progeny, S1587-17, was crossed to the Cat-100-6 inbred line. The parental lines and the F1 were tested in nutrient solutions containing an aluminum activity gradient of 0-93 ⋅ 10-6. The heterozygote behaves like the tolerant parent at aluminum activities up to 40 ⋅ 10-6 and showed an intermediate phenotype at higher aluminum concentrations. Histological sections of aluminum-treated roots from tolerant and sensitive plants stained with hematoxylin, an aluminum marker, showed a progressive destruction of the root tip of the aluminum-sensitive genotype over time and indicated that tolerance in Cat-100-6 could be due to an aluminum exclusion mechanism. Segregation analysis of the F2 and backcross to the sensitive parent based on root morphology of plants subjected to an aluminum activity of 30 ⋅ 10-6 showed the typical 3:1 and 1:1 tolerant:sensitive segregation ratios, respectively, indicating that tolerance in the Cat-100-6 inbred maize line is controlled by a single nuclear, semidominant gene, named Alm1.
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Affiliation(s)
- D H Moon
- Departamento de Genética e Evolução, Instituto de Biologia, Estadual de Campinas, Brazil, , , , , , BR
| | - L M M Ottoboni
- Departamento de Genética e Evolução, Instituto de Biologia, Estadual de Campinas, Brazil, , , , , , BR
| | - A P Souza
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil, , , , , , BR
| | - S T Sibov
- Departamento de Genética e Evolução, Instituto de Biologia, Estadual de Campinas, Brazil, , , , , , BR
| | - M Gaspar
- Departamento de Genética e Evolução, Instituto de Biologia, Estadual de Campinas, Brazil, , , , , , BR
| | - P Arruda
- Departamento de Genética e Evolução, Instituto de Biologia, Estadual de Campinas, Brazil, , , , , , BR
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37
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Goncalves-Butruille M, Szajner P, Torigoi E, Leite A, Arruda P. Purification and Characterization of the Bifunctional Enzyme Lysine-Ketoglutarate Reductase-Saccharopine Dehydrogenase from Maize. Plant Physiol 1996; 110:765-771. [PMID: 12226216 PMCID: PMC157775 DOI: 10.1104/pp.110.3.765] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The first enzyme of the lysine degradation pathway in maize (Zea mays L.), lysine-ketoglutarate reductase, condenses lysine and [alpha]-ketoglutarate into saccharopine using NADPH as a cofactor, whereas the second, saccharopine dehydrogenase, converts saccharopine to [alpha]-aminoadipic-[delta]-semialdehyde and glutamic acid using NAD+ or NADP+ as a cofactor. The reductase and dehydrogenase activities are optimal at pH 7.0 and 9.0, respectively. Both enzyme activities, co-purified on diethylaminoethyl-cellulose and gel filtration columns, were detected on nondenaturing polyacrylamide gels as single bands with identical electrophoretic mobilities and share tissue specificity for the endosperm. The highly purified preparation containing the reductase and dehydrogenase activities showed a single polypeptide band of 125 kD on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The native form of the enzyme is a dimer of 260 kD. Limited proteolysis with elastase indicated that lysine-ketoglutarate reductase and saccharopine dehydrogenase from maize endosperm are located in two functionally independent domains of a bifunctional polypeptide.
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Affiliation(s)
- M. Goncalves-Butruille
- Departamento de Genetica e Evolucao, Instituto de Biologia (M.G.-B., P.S., E.T., P.A.), and Centro de Biologia Molecular e Engenharia Genetica (A.L., P.A.), Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil
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38
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Cord Neto G, Yunes JA, da Silva MJ, Vettore AL, Arruda P, Leite A. The involvement of Opaque 2 on beta-prolamin gene regulation in maize and Coix suggests a more general role for this transcriptional activator. Plant Mol Biol 1995; 27:1015-29. [PMID: 7766871 DOI: 10.1007/bf00037028] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The maize opaque 2 (o2) mutation is known to have numerous pleiotropic effects. Some polypeptides have their expression depressed while others are enhanced. The best characterized effects of the o2 mutation are those exerted on endosperm genes encoding the storage protein class of the 22 kDa alpha-zeins and the ribosome inactivating protein b-32. The Opaque 2 (O2) locus encodes a basic domain-leucine zipper DNA-binding factor, O2, which transcriptionally regulates these genes. In the maize-related grass Coix lacryma-jobi, an O2-homologous protein regulates the 25 kDa alpha-coixin family. We show in this paper that O2 transcriptionally regulates the structurally and developmentally different class of the beta-prolamins. A new O2-binding box was identified in beta-prolamin genes from maize and Coix that, together with the boxes previously identified in other endosperm expressed genes, forms a curious collection of O2 cis elements. This may have regulatory implications on the role of O2 in the mechanism that controls coordinated gene expression in the developing endosperm. Considering that the O2 locus controls at least three distinct classes of genes in maize endosperm, we propose that the O2 protein may play a more general role in maize endosperm development than previously conceived.
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Affiliation(s)
- G Cord Neto
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil
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39
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Fonseca L, Rangel V, Lustosa P, Lannes D, Aguiar LC, Flavoni L, Arruda P, de-Meis L. Productivity versus promised results: one of the dilemmas of biotechnology in Brazil. Braz J Med Biol Res 1994; 27:2709-20. [PMID: 7549995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In 1983 a new funding program--PADCT ("Programa de Apoio ao Desenvolvimento Cientifico e Tecnológico")--was created in Brazil to stimulate the development of research projects related to what was established as technological priorities. In this paper 3 features of the Biotechnology/Health subprogram of PADCT were studied: a) to what extent productivity of the leaders of the research projects affected the way they were evaluated by the award panel, b) the conflict of interests that might result from the composition of the award panel, and c) the final impact of the program on science and technology. In our sample of 210 submitted projects, 62 were funded. The data suggest that the selection of projects did not ensure a better funding for the more productive research leaders. The presence on the award panel of at least one member from the same institution of a given project increased the chance of its approval but, after approval, it had no influence on the amount of funds granted. In a subsample of 21 scientists, support to 24 projects did not increase the productivity level and 4 products in a preliminary phase of development were reported. The issue of trying to solve problems in areas where there is no established scientific competence is discussed.
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Affiliation(s)
- L Fonseca
- Departamento de Bioquímica, Universidade Federal do Rio de Janeiro, Brasil
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40
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de Freitas FA, Yunes JA, da Silva MJ, Arruda P, Leite A. Structural characterization and promoter activity analysis of the gamma-kafirin gene from sorghum. Mol Gen Genet 1994; 245:177-86. [PMID: 7816025 DOI: 10.1007/bf00283265] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A genomic clone encoding the gamma-kafirin gene from sorghum was isolated and sequenced. A 2938 bp sequenced fragment includes an intronless open reading frame of 636 nucleotides encoding a putative polypeptide of 212 amino acids. Comparison of the deduced amino acid sequence of gamma-kafirin with the published sequences of gamma-prolamins of maize, and Coix revealed highly conserved domains. The N-terminal region of these proteins contains the conserved hexapeptide PPPVHL, which is repeated eight times in gamma-zein, four times in gamma-kafirin and three times in gamma-coixin. The number of PPPVHL repeats accounts predominantly for the differences in the molecular weights of gamma-prolamins. Several putative regulatory sequences common to the gamma-kafirin and gamma-zein genes were identified in both the 5' and the 3' flanking regions. Putative GCN4-like regulatory sequences were found at positions -192 and -476 in the 5' flanking region of gamma-kafirin. In the 3' noncoding region, three putative polyadenylation signals, two AATAAT and one AATGAA, were found at positions +658, +716, and +785, respectively. In order to investigate the role of the putative GCN4-like motifs and other possible cis-acting element(s) of the gamma-kafirin promoter, a series of deleted and chimeric promoter constructs were introduced into maize, Coix and sorghum tissues by particle bombardment. Histochemical analysis of beta-glucuronidase (GUS) activity in different tissues indicated that the element(s) responsible for tissue specificity is probably located in the 285-bp proximal region of the promoter, while the remaining promoter sequence seems to carry the element(s) responsible for the quantitative response.
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Affiliation(s)
- F A de Freitas
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, SP, Brazil
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41
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Ramos RS, Caldeira MT, Arruda P, De Meis L. The Two Km's for ATP of Corn-Root H+-ATPase and the Use of Glucose-6-Phosphate and Hexokinase as an ATP-Regenerating System. Plant Physiol 1994; 105:853-859. [PMID: 12232248 PMCID: PMC160732 DOI: 10.1104/pp.105.3.853] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plasma membrane vesicles derived from corn (Zea mays L.) roots retain a membrane-bound H+-ATPase that is able to form a H+ gradient across the vesicle membranes. The activity of this ATPase is enhanced 2- to 3-fold when Triton X-100 or lysophosphatidylcholine is added to the medium at a protein:detergent ratio of 2:1 (w/w). In the absence of detergent, the ATPase exhibits only one Km for ATP (0.1-0.2 mM), which is the same as for the pumping of H+. After the addition of either Triton X-100 or lysophosphatidylcholine, two Km's for ATP are detected, one in the range of 1 to 3 [mu]M and a second in the range of 0.1 to 0.2 mM. The Vmax of the second Km for ATP increases as the temperature of the assay medium is raised from 15[deg]C to 38[deg]C. The Arrhenius plot reveals a single break at 30[deg]C, both in the absence and in the presence of detergents. In the presence of Triton X-100 the H+-ATPase catalyzes the cleavage of glucose-6-phosphate when both hexokinase and ADP are included in the assay medium. There is no measurable cleavage when the apparent affinity for ATP of the H+-ATPase is not enhanced by Triton X-100 or when 1 mM glucose is included in the assay medium. These data indicate that when the high-affinity Km for ATP is unmasked with the use of detergent, the ATPase can use glucose-6-phosphate and hexokinase as an ATP-regenerating system.
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Affiliation(s)
- R. S. Ramos
- Instituto de Ciencias Biomedicas, Departamento de Bioquimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, CEP 21941-590, Brazil (R.S.R., M.T.C., L.d.M.)
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42
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Yunes JA, Cord Neto G, da Silva MJ, Leite A, Ottoboni LM, Arruda P. The transcriptional activator Opaque2 recognizes two different target sequences in the 22-kD-like alpha-prolamin genes. Plant Cell 1994; 6:237-49. [PMID: 8148647 PMCID: PMC160430 DOI: 10.1105/tpc.6.2.237] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The maize Opaque2 (O2) protein is a "leucine zipper" DNA binding factor that interacts with the sequence TCCACGTAGA in the promoters of the 22-kD alpha-zein genes and activates its transcription. A completely different consensus sequence (GATGAPyPuTGPu) identified in b-32, a gene that encodes an abundant albumin that is also under control of the O2 locus, can also be bound by the O2 protein. We showed that the gene encoding the 22-kD-like alpha-coixin, the alpha-prolamin of the maize-related grass Coix, can also be transactivated by the O2 protein. A binding assay in vitro and footprint analysis demonstrated that the GACATGTC sequence of the alpha-coixin promoter can be recognized and protected by the maize O2 protein. Employing transient expression experiments in immature maize endosperm and tobacco mesophyll protoplasts, we demonstrated that the O2 protein can activate expression of the beta-glucuronidase reporter gene placed under the control of the 22-kD-like alpha-coixin promoter. We also demonstrated that a 22-kD-like alpha-coixin pseudogene promoter is transactivated by the maize O2 protein.
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Affiliation(s)
- J A Yunes
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil
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43
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Ottoboni LM, Leite A, Yunes JA, Targon ML, de Souza Filho GA, Arruda P. Sequence analysis of 22 kDa-like alpha-coixin genes and their comparison with homologous zein and kafirin genes reveals highly conserved protein structure and regulatory elements. Plant Mol Biol 1993; 21:765-778. [PMID: 8467075 DOI: 10.1007/bf00027110] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Several genomic and cDNA clones encoding the 22 kDa-like alpha-coixin, the alpha-prolamin of Coix seeds, were isolated and sequenced. Three contiguous 22 kDa-like alpha-coixin genes designated alpha-3A, alpha-3B and alpha-3C were found in the 15 kb alpha-3 genomic clone. The alpha-3A and alpha-3C genes presented in-frame stop codons at position +652. The two genes with truncated ORFs are flanking the alpha-3B gene, suggesting that the three alpha-coixin genes may have arisen by tandem duplication and that the stop codon was introduced before the duplication. Comparison of the deduced amino acid sequences of alpha-coixin clones with the published sequences of 22 kDa alpha-zein and 22 kDa-like alpha-kafirin revealed a highly conserved protein structure. The protein consists of an N-terminus, containing the signal peptide, followed by ten highly conserved tandem repeats of 15-20 amino acids flanked by polyglutamines, and a short C-terminus. The difference between the 22 kDa-like alpha-prolamins and the 19 kDa alpha-zein lies in the fact that the 19 kDa protein is exactly one repeat motif shorter than the 22 kDa proteins. Several putative regulatory sequences common to the zein and kafirin genes were identified within both the 5' and 3' flanking regions of alpha-3B. Nucleotide sequences that match the consensus TATA, CATC and the ca. -300 prolamin box are present at conserved positions in alpha-3B relative to zein and kafirin genes. Two putative Opaque-2 boxes are present in alpha-3B that occupies approximately the same positions as those identified for the 22 kDa alpha-zein and alpha-kafirin genes. Southern hybridization, using a fragment of a maize Opaque-2 cDNA clone as a probe, confirmed the presence of Opaque-2 homologous sequences in the Coix and sorghum genomes. The overall results suggest that the structural and regulatory genes involved in the expression of the 22 kDa-like alpha-prolamin genes of Coix, sorghum and maize, originated from a common ancestor, and that variations were introduced in the structural and regulatory sequences after species separation.
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Affiliation(s)
- L M Ottoboni
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, SP, Brazil
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44
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Garratt R, Oliva G, Caracelli I, Leite A, Arruda P. Studies of the zein-like alpha-prolamins based on an analysis of amino acid sequences: implications for their evolution and three-dimensional structure. Proteins 1993; 15:88-99. [PMID: 8451243 DOI: 10.1002/prot.340150111] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
alpha-Prolamins are the major seed storage proteins of species of the grass tribe Andropogonea. They are unusually rich in glutamine, proline, alanine, and leucine residues and their sequences show a series of tandem repeats presumed to be the result of multiple intragenic duplication. Two new sequences of alpha-prolamin clones from Coix (pBCX25.12 and pBCX25.10) are compared with similar clones from maize and Sorghum in order to investigate evolutionary relationships between the repeat motifs and to propose a schematic model for their three-dimensional structure based on hydrophobic membrane-helix propensities and helical "wheels." A scheme is proposed for the most recent events in the evolution of the central part of the molecule (repeats 3 to 8) which involves two partial intragenic duplications and in which contemporary odd-numbered and even-numbered repeats arise from common ancestors, respectively. Each pair of repeats is proposed to form an antiparallel alpha-helical hairpin and that the helices of the molecule as a whole are arranged on a hexagonal net. The majority of helices show six faces of alternating hydrophobic and polar residues, which give rise to intersticial holes around each helix which alternate in chemical character. The model is consistent with proteins which contain different numbers of repeats, with oligomerization and with the dense packaging of alpha-prolamins within the protein body of the seed endosperm.
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Affiliation(s)
- R Garratt
- Departamento de Física e Ciência dos Materiais, Universidade de São Paulo, Brasil
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45
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Brochetto-Braga MR, Leite A, Arruda P. Partial purification and characterization of lysine-ketoglutarate reductase in normal and opaque-2 maize endosperms. Plant Physiol 1992; 98:1139-47. [PMID: 16668738 PMCID: PMC1080319 DOI: 10.1104/pp.98.3.1139] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Lysine-ketoglutarate reductase catalyzes the first step of lysine catabolism in maize (Zea mays L.) endosperm. The enzyme condenses l-lysine and alpha-ketoglutarate into saccharopine using NADPH as cofactor. It is endosperm-specific and has a temporal pattern of activity, increasing with the onset of kernel development, reaching a peak 20 to 25 days after pollination, and there-after decreasing as the kernel approaches maturity. The enzyme was extracted from the developing maize endosperm and partially purified by ammonium-sulfate precipitation, anion-exchange chromatography on DEAE-cellulose, and affinity chromatography on Blue-Sepharose CL-6B. The preparation obtained from affinity chromatography was enriched 275-fold and had a specific activity of 411 nanomoles per minute per milligram protein. The native and denaturated enzyme is a 140 kilodalton protein as determined by polyacrylamide gel electrophoresis. The enzyme showed specificity for its substrates and was not inhibited by either aminoethyl-cysteine or glutamate. Steady-state product-inhibition studies revealed that saccharopine was a noncompetitive inhibitor with respect to alpha-ketoglutarate and a competitive inhibitor with respect to lysine. This is suggestive of a rapid equilibrium-ordered binding mechanism with a binding order of lysine, alpha-ketoglutarate, NADPH. The enzyme activity was investigated in two maize inbred lines with homozygous normal and opaque-2 endosperms. The pattern of lysine-ketoglutarate reductase activity is coordinated with the rate of zein accumulation during endosperm development. A coordinated regulation of enzyme activity and zein accumulation was observed in the opaque-2 endosperm as the activity and zein levels were two to three times lower than in the normal endosperm. Enzyme extracted from L1038 normal and opaque-2 20 days after pollination was partially purified by DEAE-cellulose chromatography. Both genotypes showed a similar elution pattern with a single activity peak eluted at approximately 0.2 molar KCL. The molecular weight and physical properties of the normal and opaque-2 enzymes were essentially the same. We suggest that the Opaque-2 gene, which is a transactivator of the 22 kilodalton zein genes, may be involved in the regulation of the lysine-ketoglutarate reductase gene in maize endosperm. In addition, the decreased reductase activity caused by the opaque-2 mutation may explain, at least in part, the elevated concentration of lysine found in the opaque-2 endosperm.
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Affiliation(s)
- M R Brochetto-Braga
- Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, 13081 Campinas, SP, Brazil
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46
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Leite A, de Freitas FA, Yunes JA, Arruda P. Nucleotide Sequence of a cDNA Clone Encoding gamma-Coixin from Coix lacryma-jobi Seeds. Plant Physiol 1991; 97:1604-5. [PMID: 16668595 PMCID: PMC1081211 DOI: 10.1104/pp.97.4.1604] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Affiliation(s)
- A Leite
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, 13081, Campinas, SP, Brasil
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47
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Crozier A, Arruda P, Jasmim JM, Monteiro AM, Sandberg G. Analysis of Indole-3-Acetic Acid and Related Indoles in Culture Medium from
Azospirillum lipoferum
and
Azospirillum brasilense. Appl Environ Microbiol 1988; 54:2833-7. [PMID: 16347781 PMCID: PMC204381 DOI: 10.1128/aem.54.11.2833-2837.1988] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Analysis of neutral and acidic ethyl acetate extracts from culture medium of
Azospirillum brasilense
703Ebc by high-performance liquid chromatography (HPLC) and combined gas chromatography-mass spectrometry demonstrated the presence of indole-3-acetic acid (IAA), indole-3-ethanol, indole-3-methanol, and indole-3-lactic acid. IAA in media of 20 strains of
A. brasilense
and
Azospirillum lipoferum
was analyzed quantitatively by both the colorimetric Salkowski assay and HPLC-based isotopic dilution procedures. There was little correlation between the estimates obtained with the two procedures. For instance, the Salkowski assay suggested that the culture medium from
A. brasilense
703Ebc contained 26.1 μg of IAA ml
−1
, whereas HPLC revealed the presence of only 0.5 μg of IAA ml
−1
. Equivalent estimates with
A. brasilense
204Ed were 10.5 and 0.01 μg of IAA ml
−1
, respectively. The data demonstrate that the Salkowski assay is not a reliable method for measuring the IAA content of
Azospirillum
culture medium and that estimates in excess of 10 μg of IAA ml
−1
should be viewed with particular caution. Metabolism of [2′-
14
C]IAA by
A. brasilense
703Ebc yielded radiolabeled indole-3-methanol, whereas roots of maize (
Zea mays
L.) seedlings gave rise to [
14
C]oxindole-3-acetic acid and an array of polar metabolites. Metabolism of [2′-
14
C]IAA by maize roots inoculated with
A. brasilense
703Ebc produced a metabolic profile characteristic of maize rather than
Azospirillum
species.
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Affiliation(s)
- A Crozier
- Department of Botany, The University of Glasgow, Glasgow G12 8QQ, United Kingdom; Departments of Genetics and Evolution and Plant Physiology, Institute of Biology, Universidade Estadual de Campinas, 13081 Campinas, Sao Paulo, Brazil; and Department of Forest Genetics and Plant Physiology, The Swedish University of Agricultural Sciences, S-901 83 Umeä, Sweden
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48
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Arruda P, Bright SW, Kueh JS, Lea PJ, Rognes SE. Regulation of Aspartate Kinase Isoenzymes in Barley Mutants Resistant to Lysine plus Threonine : Construction and Analysis of Combinations of the Lt1a, Lt1b, and Lt2 Mutant Genes. Plant Physiol 1984; 76:442-6. [PMID: 16663861 PMCID: PMC1064307 DOI: 10.1104/pp.76.2.442] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Two homozygous mutant lines of barley (Hordeum vulgare L.) R3202 (Lt1b/Lt1b) and R3004 (Lt2/Lt2), are resistant to lysine plus threonine. They contain aspartate kinase isoenzymes with lost or decreased feedback sensitivity to lysine in either isoenzyme AKII (R3202) or isoenzyme AKIII (R3004). A homozygous double mutant line (Lt1b/Lt1b, Lt2/Lt2) has now been constructed that grows vigorously on 8 millimolar lysine, 8 millimolar threonine, and 1 millimolar arginine. Both AKII and AKIII from the double mutant have altered lysine sensitivities, identical to those previously observed in R3202 and R3004, respectively. Aspartate kinase activity in extracts of leaves, roots, and the maturing endosperm of the double mutant was much less sensitive to lysine inhibition than the enzyme in comparable extracts of the parent cv Bomi, suggesting that aspartate kinase is expressed in a similar manner in different tissues of barley.A further mutant, R2501, resistant to lysine plus threonine has now given rise to a homozygous line (Lt1a/Lt1a), which had previously not been possible. AKII isolated from the homozygous line was completely insensitive to 10 millimolar lysine; however, the combined action of 10 millimolar lysine and 0.8 millimolar S-adenosylmethionine inhibited it by 60%, demonstrating the retention of some of the regulatory characteristics of the wild type enzyme.
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Affiliation(s)
- P Arruda
- Biochemistry Department, Rothamsted Experimental Station, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
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49
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Abstract
Lysine-ketoglutarate reductase activity was detected and characterized in the developing endosperm of maize (Zea mays L.). The enzyme showed specificity for its substrates: lysine, alpha-ketoglutarate, and NADPH. Formation of the reaction product saccharopine was demonstrated. The pH optimum of the enzyme was close to 7, and the K(m) for lysine and alpha-ketoglutarate were 5.2 and 1.8 millimolar, respectively.
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Affiliation(s)
- P Arruda
- Department of Genetics and Evolution, Instituto de Biologia, Universidade Estadual de Campinas, 13100 Campinas, SP., Brazil
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50
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Huggins D, Costa VP, Figueiredo B, Gurgel GB, Arruda P. [Stilbazium iodide in the treatment of tricocephaliasis and ascariasis]. Hospital (Rio J) 1969; 75:511-5. [PMID: 5311209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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