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1.
Braz. J. Biol. ; 82: 1-8, 2022. graf
Artigo em Inglês | VETINDEX | ID: vti-31632

RESUMO

In this study, we investigated the proline and protease production of different bacteria in several organic waste materials. Our aim was to produce proline and protease economically in waste that is abundantly available while reducing its environmental impact. 5 ml of different organic waste materials (OWW: Olive waste water; N.B: Nutrient Broth; EW: Eggshell; PBS: PBS buffer; PLW: Peach leaf wastes; TCW: Turkish coffee wastes; TWW: Tea waste water; WCW: Waste cheese whey; WFO: Waste frying oil) were placed in 10 ml grow tubes, inoculated and incubated for 24 h. Phosphate-buffered saline and 10% solutions of different organic wastes were added. These cultures were subsequently incubated at 37°C for 24 h. Cells were harvested at 24 h for L-proline assay. 1 ml of culture was transferred by pipette into an Eppendorf tube and centrifuged at 14,000 rpm for 20 min at room temperature. Cellular debris was removed by centrifuge and the supernatant was used for proline activity assays. Protease activity was determined using a modified method with casein as the substrate. We found that proline and protease can easily be produced economically using Turkish coffee wastes (TCW), Waste cheese whey (WCW) and Olive waste water (OWW) organic waste. We believe that this study will result in similar research leading to the economical use of these waste materials thus reducing their impact on the environment.(AU)


Neste estudo, investigamos a produção de prolina e protease de diferentes bactérias em diversos resíduos orgânicos. Nosso objetivo era produzir prolina e protease economicamente em resíduos que estão disponíveis em abundância, reduzindo seu impacto ambiental. Cinco ml de diferentes materiais de resíduos orgânicos (OWW: resíduos de azeitona; NB: caldo nutriente; EW: casca de ovo; PBS: tampão PBS; PLW: resíduos de folhas de pêssego; TCW: resíduos de café turco; TWW: resíduos de chá; WCW: resíduos de queijo soro de leite; WFO: óleo de fritura residual) foram colocados em tubos de cultivo de 10 ml, inoculados e incubados por 24 horas. Adicionaram-se solução salina tamponada com fosfato e soluções a 10% de diferentes resíduos orgânicos. Essas culturas foram subsequentemente incubadas a 37° C durante 24 h. As células foram colhidas às 24 h para o ensaio de L-prolina. Um ml de cultura foi transferido por pipeta para um tubo Eppendorf e centrifugado a 14.000 rpm, por 20 min, em temperatura ambiente. Os detritos celulares foram removidos por centrifugação e o sobrenadante foi usado para ensaios de atividade de prolina. A atividade da protease foi determinada usando um método modificado com caseína como substrato. Descobrimos que a prolina e a protease podem ser facilmente produzidas economicamente, usando resíduos de café turco (TCW), resíduos de soro de queijo (WCW) e resíduos orgânicos de água de oliva (OWW). Acreditamos que este estudo resultará em pesquisas semelhantes, levando ao uso econômico desses materiais residuais, reduzindo, assim, seu impacto no meio ambiente.(AU)


Assuntos
Biodegradação Ambiental , Resíduos de Alimentos , Peptídeo Hidrolases/biossíntese , Prolina/biossíntese , Pseudomonas aeruginosa
2.
Braz. j. biol ; 82: 1-8, 2022. graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1468530

RESUMO

In this study, we investigated the proline and protease production of different bacteria in several organic waste materials. Our aim was to produce proline and protease economically in waste that is abundantly available while reducing its environmental impact. 5 ml of different organic waste materials (OWW: Olive waste water; N.B: Nutrient Broth; EW: Eggshell; PBS: PBS buffer; PLW: Peach leaf wastes; TCW: Turkish coffee wastes; TWW: Tea waste water; WCW: Waste cheese whey; WFO: Waste frying oil) were placed in 10 ml grow tubes, inoculated and incubated for 24 h. Phosphate-buffered saline and 10% solutions of different organic wastes were added. These cultures were subsequently incubated at 37°C for 24 h. Cells were harvested at 24 h for L-proline assay. 1 ml of culture was transferred by pipette into an Eppendorf tube and centrifuged at 14,000 rpm for 20 min at room temperature. Cellular debris was removed by centrifuge and the supernatant was used for proline activity assays. Protease activity was determined using a modified method with casein as the substrate. We found that proline and protease can easily be produced economically using Turkish coffee wastes (TCW), Waste cheese whey (WCW) and Olive waste water (OWW) organic waste. We believe that this study will result in similar research leading to the economical use of these waste materials thus reducing their impact on the environment.


Neste estudo, investigamos a produção de prolina e protease de diferentes bactérias em diversos resíduos orgânicos. Nosso objetivo era produzir prolina e protease economicamente em resíduos que estão disponíveis em abundância, reduzindo seu impacto ambiental. Cinco ml de diferentes materiais de resíduos orgânicos (OWW: resíduos de azeitona; NB: caldo nutriente; EW: casca de ovo; PBS: tampão PBS; PLW: resíduos de folhas de pêssego; TCW: resíduos de café turco; TWW: resíduos de chá; WCW: resíduos de queijo soro de leite; WFO: óleo de fritura residual) foram colocados em tubos de cultivo de 10 ml, inoculados e incubados por 24 horas. Adicionaram-se solução salina tamponada com fosfato e soluções a 10% de diferentes resíduos orgânicos. Essas culturas foram subsequentemente incubadas a 37° C durante 24 h. As células foram colhidas às 24 h para o ensaio de L-prolina. Um ml de cultura foi transferido por pipeta para um tubo Eppendorf e centrifugado a 14.000 rpm, por 20 min, em temperatura ambiente. Os detritos celulares foram removidos por centrifugação e o sobrenadante foi usado para ensaios de atividade de prolina. A atividade da protease foi determinada usando um método modificado com caseína como substrato. Descobrimos que a prolina e a protease podem ser facilmente produzidas economicamente, usando resíduos de café turco (TCW), resíduos de soro de queijo (WCW) e resíduos orgânicos de água de oliva (OWW). Acreditamos que este estudo resultará em pesquisas semelhantes, levando ao uso econômico desses materiais residuais, reduzindo, assim, seu impacto no meio ambiente.


Assuntos
Biodegradação Ambiental , Peptídeo Hidrolases/biossíntese , Prolina/biossíntese , Resíduos de Alimentos , Pseudomonas aeruginosa
3.
Mol Biol Rep ; 47(2): 1033-1043, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31749121

RESUMO

Eugenia uniflora is an Atlantic Forest native species, occurring in contrasting edaphoclimatic environments. The identification of genes involved in response to abiotic factors is very relevant to help in understanding the processes of local adaptation. 1-Pyrroline-5-carboxylate synthetase (P5CS) is one interesting gene to study in this species since it encodes a key enzyme of proline biosynthesis, which is an osmoprotectant during abiotic stress. Applying in silico analysis, we identified one P5CS gene sequence of E. uniflora (EuniP5CS). Phylogenetic analysis, as well as, gene and protein structure investigation, revealed that EuniP5CS is a member of P5CS gene family. Plants of E. uniflora from two distinct environments (restinga and riparian forest) presented differences in the proline accumulation and P5CS expression levels under growth-controlled conditions. Both proline accumulation and gene expression level of EuniP5CS were higher in the genotypes from riparian forest than those from restinga. When these plants were submitted to drought stress, EuniP5CS gene was up-regulated in the plants from restinga, but not in those from riparian forest. These results demonstrated that EuniP5CS is involved in proline biosynthesis in this species and suggest that P5CS gene may be an interesting candidate gene in future studies to understand the processes of local adaptation in E. uniflora.


Assuntos
Eugenia/genética , Glutamato-5-Semialdeído Desidrogenase/genética , Complexos Multienzimáticos/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Aldeído Desidrogenase/genética , Aldeído Desidrogenase/metabolismo , Secas , Eugenia/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Glutamato-5-Semialdeído Desidrogenase/metabolismo , Ligases/metabolismo , Complexos Multienzimáticos/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Filogenia , Plantas/metabolismo , Prolina/biossíntese , Pirróis/metabolismo , Estresse Fisiológico/genética
4.
Plant Physiol Biochem ; 113: 133-140, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28213180

RESUMO

Global interest in sugarcane has increased significantly in recent years because of its economic impact on sustainable energy production. The purpose of the present study was to evaluate changes in the concentrations of total sugars, amino acids, free proline, and total proteins by colorimetric analyses and nuclear magnetic resonance (NMR) to perform a metabolic profiling of a water-soluble fraction of symplastic sap in response to the constitutive expression of a mutant Δ1-pyrroline-5-carboxylate synthetase (P5CS) gene from Vigna aconitifolia. However, there was not a significant increase in the free proline content in the sap of transgenic plants compared to the non-transformed control plants. The most noticeable difference between the two genotypes was an almost two-fold increase in the accumulation of sucrose in the stem internodes of P5CS transgenic sugarcane plants. The results presented in this work showed that transgenic sugarcane plants with increased levels of free proline accumulates high soluble sugar content and, therefore, may represent a novel genotype for improving sugarcane cultivars.


Assuntos
Prolina/biossíntese , Saccharum/genética , Saccharum/metabolismo , 1-Pirrolina-5-Carboxilato Desidrogenase/genética , 1-Pirrolina-5-Carboxilato Desidrogenase/metabolismo , Biomassa , Etanol/metabolismo , Genótipo , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/metabolismo , Proteínas de Plantas/biossíntese , Proteínas de Plantas/metabolismo , Caules de Planta/metabolismo , Plantas Geneticamente Modificadas , Prolina/metabolismo , Saccharum/enzimologia , Sacarose/metabolismo , Vigna/enzimologia , Vigna/genética , Água/química
5.
Plant Physiol Biochem ; 113: 78-88, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28189052

RESUMO

The annual Zea mays ssp. mexicana L., a member of the teosinte group, is a close wild relative of maize and thus can be effectively used in maize improvement. In this study, an ICE-like gene, ZmmICE1, was isolated from a cDNA library of RNA-Seq from cold-treated seedling tissues of Zea mays ssp. mexicana L. The deduced protein of ZmmICE1 contains a highly conserved basic helix-loop-helix (bHLH) domain and C-terminal region of ICE-like proteins. The ZmmICE1 protein localizes to the nucleus and shows sumoylation when expressed in an Escherichia coli reconstitution system. In addition, yeast one hybrid assays indicated that ZmmICE1 has transactivation activities. Moreover, ectopic expression of ZmmICE1 in the Arabidopsis ice1-2 mutant increased freezing tolerance. The ZmmICE1 overexpressed plants showed lower electrolyte leakage (EL), reduced contents of malondialdehyde (MDA). The expression of downstream cold related genes of Arabidopsis C-repeat-binding factors (AtCBF1, AtCBF2 and AtCBF3), cold-responsive genes (AtCOR15A and AtCOR47), kinesin-1 member gene (AtKIN1) and responsive to desiccation gene (AtRD29A) was significantly induced when compared with wild type under low temperature treatment. Taken together, these results indicated that ZmmICE1 is the homolog of Arabidopsis inducer of CBF expression genes (AtICE1/2) and plays an important role in the regulation of freezing stress response.


Assuntos
Adaptação Fisiológica/genética , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/genética , Zea mays/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/biossíntese , Proteínas de Arabidopsis/metabolismo , Sequência de Bases , Temperatura Baixa , Congelamento , Malondialdeído/metabolismo , Plantas Geneticamente Modificadas , Prolina/biossíntese , Prolina/genética , RNA de Plantas/genética , Estresse Fisiológico/genética , Sumoilação/genética , Fatores de Transcrição/biossíntese , Fatores de Transcrição/metabolismo , Zea mays/metabolismo
6.
Plant Physiol Biochem ; 113: 149-160, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28214728

RESUMO

Phospholipase D (PLD) hydrolyses phospholipids to yield phosphatidic acid (PA) and a head group, and is involved in responses to a variety of environmental stresses, including chilling and freezing stress. Barley responses to chilling stress (induced by incubating seedlings at 4 °C) are dynamic and the duration of stress, either short (0-180 min) or long-term (24-36 h) had a significant impact on the response. We investigated the roles of PLD/PA in responses of barley (Hordeum vulgare) seedlings to short and long-term chilling stress, based on regulation of proline and reactive oxygen species (ROS) levels. Short-term chilling stress caused rapid and transient increases in PLD activity, proline level, and ROS levels in young leaves. PLD has the ability to catalyse the transphosphatidylation reaction leading to formation of phosphatidylalcohol (preferentially, to PA). Pre-treatment of seedlings with 1-butanol significantly increased proline synthesis but decreased ROS (H2O2) formation. These observations suggest that PLD is a negative regulator of proline synthesis, whereas PA/PLD promote ROS signals. Exogenous PA pre-treatment reduced the proline synthesis but enhanced H2O2 formation. Effects of long-term chilling stress on barley seedlings differed from those of short-term chilling stress. E.g., PLD activity was significantly reduced in young leaves and roots, whereas proline synthesis and ROS signals were increased in roots. Exogenous ROS application enhanced proline level while exogenous proline application reduced ROS level and modulated some effects of long-term chilling stress. Our findings suggest that PLD contributes to signalling pathways in responses to short-term chilling stress in barley seedling, through regulation of the balance between proline and ROS levels. In contrast, reduced PLD activity in the response to long-term chilling stress did not affect proline level. Increased ROS levels may reflect an antioxidant system that is affected by chilling stress and positively compensated by changes in proline level. Implications of our findings are discussed in regard to adaptation strategies of barley seedlings to low temperatures.


Assuntos
Hordeum/metabolismo , Peróxido de Hidrogênio/metabolismo , Ácidos Fosfatídicos/farmacologia , Fosfolipase D/farmacologia , Prolina/metabolismo , Plântula/metabolismo , 1-Butanol/farmacologia , Adaptação Biológica/fisiologia , Antioxidantes/metabolismo , Temperatura Baixa/efeitos adversos , Congelamento/efeitos adversos , Glicerofosfolipídeos/metabolismo , Hordeum/efeitos dos fármacos , Metabolismo dos Lipídeos , Ácidos Fosfatídicos/metabolismo , Fosfolipase D/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Prolina/biossíntese , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos
7.
Magn Reson Chem ; 52(8): 422-9, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24842075

RESUMO

The accumulation of proline is a typical physiological response to abiotic stresses in higher plants. 'Swingle' citrumelo, an important rootstock for citrus production, has been modified with a mutated Δ(1)-pyrroline-5-carboxylate synthetase gene (VaP5CSF129A) linked to the cauliflower mosaic virus 35S promoter to induce the overproduction of free proline. This paper presents a comparative metabolomic study of nontransgenic versus transgenic 'Swingle' citrumelo plants with high endogenous proline. (1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and multivariate analysis showed significant differences in some metabolites between the nontransgenic and transgenic leaves and roots. The overproduction of proline has reduced the sucrose content in transgenic leaves, revealing a metabolic cost for these plants. In roots, the high level of free proline acts for the adjustment of cation-anion balance, causing the reduction of acetic acid content. The same sucrose level in roots indicates that they can be considered as sucrose sink. Similar behavior may be waited for fruits produced on transgenic rootstock.


Assuntos
Citrus/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Metabolômica , Prolina/biossíntese , Caulimovirus/genética , Citrus/genética , Regiões Promotoras Genéticas , Espectroscopia de Prótons por Ressonância Magnética
8.
J Plant Physiol ; 169(1): 41-9, 2012 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-21903295

RESUMO

The role of the δ-ornithine amino transferase (OAT) pathway in proline synthesis is still controversial and was assessed in leaves of cashew plants subjected to salinity. The activities of enzymes and the concentrations of metabolites involved in proline synthesis were examined in parallel with the capacity of exogenous ornithine and glutamate to induce proline accumulation. Proline accumulation was best correlated with OAT activity, which increased 4-fold and was paralleled by NADH oxidation coupled to the activities of OAT and Δ(1)-pyrroline-5-carboxylate reductase (P5CR), demonstrating the potential of proline synthesis via OAT/P5C. Overall, the activities of GS, GOGAT and aminating GDH remained practically unchanged under salinity. The activity of P5CR did not respond to NaCl whereas Δ(1)-pyrroline-5-carboxylate dehydrogenase was sharply repressed by salinity. We suggest that if the export of P5C from the mitochondria to the cytosol is possible, its subsequent conversion to proline by P5CR may be important. In a time-course experiment, proline accumulation was associated with disturbances in amino acid metabolism as indicated by large increases in the concentrations of ammonia, free amino acids, glutamine, arginine and ornithine. Conversely, glutamate concentrations increased moderately and only within the first 24h. Exogenous feeding of ornithine as a precursor was very effective in inducing proline accumulation in intact plants and leaf discs, in which proline concentrations were several times higher than glutamate-fed or salt-treated plants. Our data suggest that proline accumulation might be a consequence of salt-induced increase in N recycling, resulting in increased levels of ornithine and other metabolites involved with proline synthesis and OAT activity. Under these metabolic circumstances the OAT pathway might contribute significantly to proline accumulation in salt-stressed cashew leaves.


Assuntos
Anacardium/metabolismo , Nitrogênio/metabolismo , Ornitina-Oxo-Ácido Transaminase/metabolismo , Ornitina/metabolismo , Prolina/metabolismo , Tolerância ao Sal/fisiologia , Estresse Fisiológico/fisiologia , Ensaios Enzimáticos , Glutamato Desidrogenase/metabolismo , Glutamato Sintase (NADH)/metabolismo , Glutamato-Amônia Ligase/metabolismo , Glutamatos/administração & dosagem , Glutamatos/metabolismo , NAD/metabolismo , Ornitina/administração & dosagem , Folhas de Planta/metabolismo , Prolina/biossíntese , Pirrolina Carboxilato Redutases/metabolismo , Salinidade , delta-1-Pirrolina-5-Carboxilato Redutase
9.
Mol Genet Genomics ; 281(1): 87-97, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19002717

RESUMO

Many plants synthesize and accumulate proline in response to osmotic stress conditions. A central enzyme in the proline biosynthesis is the bifunctional enzyme Delta(1)-pyrroline-5-carboxylate synthase (P5CS) that includes two functional catalytic domains: the gamma-glutamyl kinase and the glutamic-gamma-semialdehyde dehydrogenase. This enzyme catalyzes the first two steps of the proline biosynthetic pathway and plays a central role in the regulation of this process in plants. To determine the evolutionary events that occurred in P5CS genes, partial sequences from four Neotropical trees were cloned and compared to those of other plant taxa. Molecular phylogenetic analysis indicated that P5CS duplication events have occurred several times following the emergence of flowering plants and at different frequencies throughout the evolution of monocots and dicots. Despite the high number of conserved residues in plant P5CS sequences, positive selection was observed at different regions of P5CS paralogous genes and also when dicots and monocots were contrasted.


Assuntos
Ornitina-Oxo-Ácido Transaminase/genética , Ornitina-Oxo-Ácido Transaminase/metabolismo , Plantas/enzimologia , Plantas/genética , Prolina/biossíntese , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Primers do DNA/genética , DNA de Plantas/genética , Evolução Molecular , Duplicação Gênica , Genes de Plantas , Dados de Sequência Molecular , Pressão Osmótica , Filogenia , Plantas/classificação , Homologia de Sequência de Aminoácidos , Árvores/enzimologia , Árvores/genética , Clima Tropical
10.
Plant Physiol Biochem ; 46(1): 82-92, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18054243

RESUMO

Proline (Pro) is one of the most accumulated osmolytes in salinity and water deficit conditions in plants. In the present study, we measured the Pro content, the activity and the expression level of delta 1-pyrroline-5-carboxylate synthetase (P5CS: gamma-glutamyl kinase, EC 2.7.2.11 and glutamate-5-semialdehyde dehydrogenase, EC 1.2.1.41), a key regulatory enzyme involved in the biosynthesis of Pro, in cactus pear (Opuntia streptacantha) subjected to 6, 9 and 11 days of salt stress. Treatment with NaCl of O. streptacantha young plants resulted in a decrease in the cladode thickness and root length, and in a significant and gradual accumulation of Pro in young cladodes, in a time- and concentration-dependent manner. P5CS activity, studied as gamma-glutamyl kinase, was reduced at all times as a consequence of salt treatment, except at the sixth day at 75 and 150mM of NaCl, where a slight increase was observed. We isolated an open reading frame (ORF) fragment of p5cs gene. The deduced amino acid sequence of the P5CS protein exhibited 90.4% of identity with the P5CS protein from Mesembryanthemum crystallinum. RT-PCR analysis revealed that the Osp5cs gene of O. streptacantha was induced by salt stress at 9 and 11 days of treatment. Furthermore, ABA-induced Osp5cs gene expression was observed in cladodes of cactus pear young plants. We observed an evident correlation between the transcript up-regulation and the Pro accumulation under salt stress; however, these results do not parallel with the changes in P5CS enzymatic activity. This Pro accumulation might function as an osmolyte for the intracellular osmotic adjustment and might be playing a critical role in protecting photosynthetic activity in O. streptacantha plants under salt stress.


Assuntos
Mesembryanthemum/metabolismo , Opuntia/metabolismo , Prolina/biossíntese , Cloreto de Sódio/farmacologia , Ácido Abscísico , Sequência de Aminoácidos , Relação Dose-Resposta a Droga , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/fisiologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/fisiologia , Glutamato-5-Semialdeído Desidrogenase/biossíntese , Glutamato-5-Semialdeído Desidrogenase/genética , Mesembryanthemum/genética , Dados de Sequência Molecular , Opuntia/genética , Pressão Osmótica/efeitos dos fármacos , Fosfotransferases (Aceptor do Grupo Carboxila)/biossíntese , Fosfotransferases (Aceptor do Grupo Carboxila)/genética , Fotossíntese , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Prolina/genética , Fatores de Tempo
11.
J Plant Physiol ; 164(10): 1367-76, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17604875

RESUMO

Water deficit is one of the main abiotic factors that affect spring wheat planted in subtropical regions. Accumulation of proline appears to be a promising approach to maintain the productivity of plants under stress condition. However, morphological alterations and growth reduction are observed in transgenic plants carrying genes coding for osmoprotectants controlled by constitutive promoters. We report here the effects of water deficit on wheat plants transformed with the Vigna aconitifolia Delta(1)-pyrroline-5-carboxylate synthetase (P5CS) cDNA that encodes the key regulatory enzyme in proline biosynthesis, under the control of a stress-induced promoter complex-AIPC. Transgenic wheat plants submitted to 15 days of water shortage presented a distinct response. We have found that drought resulted in the accumulation of proline. The tolerance to water deficit observed in transgenic plants was mainly due to protection mechanisms against oxidative stress and not caused by osmotic adjustment.


Assuntos
Prolina/biossíntese , Triticum/genética , Triticum/metabolismo , Água/metabolismo , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas , Fatores de Tempo , Triticum/embriologia
12.
J Biol Chem ; 268(25): 18673-8, 1993 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-8103048

RESUMO

Proline prototrophy was restored to an Escherichia coli proBA proline auxotroph by ornithine and a mothbean (Vigna aconitifolia) cDNA expression library. This novel strategy, "trans-complementation," allowed isolation of a cDNA encoding ornithine delta-aminotransferase (delta-OAT). This enzyme transaminates ornithine to glutamic-gamma-semialdehyde (GSA), thereby bypassing the block in GSA synthesis from glutamate in the proBA mutant. The identity of the mothbean enzyme was confirmed by its high sequence homology to mammalian and yeast delta-OATs as well as to a family of bacterial and fungal omega-aminotransferases and an absence of significant homology to various alpha-aminotransferases. The V. aconitifolia OAT cDNA encodes a polypeptide of 48.1 kDa. The native enzyme expressed in E. coli appears to be a monomer with Km of 2 mM for ornithine and 0.75 mM for alpha-ketoglutarate. Levels of mRNA in V. aconitifolia for delta 1-pyrroline-5-carboxylate synthetase (P5CS) and delta-OAT, the two key enzymes for proline synthesis, were monitored under different physiological conditions. Salt stress and nitrogen starvation induced P5CS mRNA levels and depressed OAT mRNA levels. Conversely, OAT mRNA level was elevated in plants supplied with excess nitrogen while the P5CS mRNA level was reduced. These data suggest that the glutamate pathway is the primary route for proline synthesis in plants during conditions of osmotic stress and nitrogen limitation whereas the ornithine pathway assumes prominence under high nitrogen input.


Assuntos
Clonagem Molecular , DNA/genética , Escherichia coli/enzimologia , Ornitina-Oxo-Ácido Transaminase/genética , Plantas/enzimologia , Prolina/biossíntese , 1-Pirrolina-5-Carboxilato Desidrogenase , Sequência de Aminoácidos , Sequência de Bases , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Fabaceae , Glutamatos/metabolismo , Ácido Glutâmico , Cinética , Dados de Sequência Molecular , Mutação , Nitrogênio/administração & dosagem , Nitrogênio/farmacologia , Ornitina-Oxo-Ácido Transaminase/química , Ornitina-Oxo-Ácido Transaminase/metabolismo , Pressão Osmótica , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/genética , Plantas/efeitos dos fármacos , Plantas/genética , Plantas Medicinais , RNA Mensageiro/metabolismo , Homologia de Sequência
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