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1.
PLoS One ; 15(5): e0233779, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470059

RESUMO

Trehalose metabolism in yeast has been linked to a variety of phenotypes, including heat resistance, desiccation tolerance, carbon-source utilization, and sporulation. The relationships among the several phenotypes of mutants unable to synthesize trehalose are not understood, even though the pathway is highly conserved. One of these phenotypes is that tps1Δ strains cannot reportedly grow on media containing glucose or fructose, even when another carbon source they can use (e.g. galactose) is present. Here we corroborate the recent observation that a small fraction of yeast tps1Δ cells do grow on glucose, unlike the majority of the population. This is not due to a genetic alteration, but instead resembles the persister phenotype documented in many microorganisms and cancer cells undergoing lethal stress. We extend these observations to show that this phenomenon is glucose-specific, as it does not occur on another highly fermented carbon source, fructose. We further demonstrate that this phenomenon appears to be related to mitochondrial complex III function, but unrelated to inorganic phosphate levels in the cell, as had previously been suggested. Finally, we found that this phenomenon is specific to S288C-derived strains, and is the consequence of a variant in the MKT1 gene.


Assuntos
Glucose/metabolismo , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Fermentação , Frutose/metabolismo , Glucosiltransferases/genética , Mutação com Perda de Função , Trealose/biossíntese
2.
Carbohydr Res ; 488: 107902, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31911362

RESUMO

Trehalose 6-phosphate (Tre6P) is an important intermediate for trehalose biosynthesis. Recent researches have revealed that Tre6P is an endogenous signaling molecule that regulates plant development and stress responses. The necessity of Tre6P in physiological studies is expected to be increasing. To achieve the cost-effective production of Tre6P, a novel approach is required. In this study, we utilized trehalose 6-phosphate phosphorylase (TrePP) from Lactococcus lactis to produce Tre6P. In the reverse phosphorolysis by the TrePP, 91.9 mM Tre6P was produced from 100 mM ß-glucose 1-phosphate (ß-Glc1P) and 100 mM glucose 6-phosphate (Glc6P). The one-pot reaction of TrePP and maltose phosphorylase (MP) enabled production of 65 mM Tre6P from 100 mM maltose, 100 mM Glc6P, and 20 mM inorganic phosphate. Addition of ß-phosphoglucomutase to this reaction produced Glc6P from ß-Glc1P and thus reduced requirement of Glc6P as a starting material. Within the range of 20-469 mM inorganic phosphate tested, the 54 mM concentration yielded the highest amount of Tre6P (33 mM). Addition of yeast increased the yield because of its glucose consumption. Finally, from 100 mmol maltose and 60 mmol inorganic phosphate, we successfully achieved production of 37.5 mmol Tre6P in a one-pot reaction (100 mL), and 9.4 g Tre6P dipotassium salt was obtained.


Assuntos
Glucosiltransferases/metabolismo , Lactococcus lactis/enzimologia , Fosfatos Açúcares/biossíntese , Trealose/análogos & derivados , Leveduras/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Metabolismo dos Carboidratos , Clonagem Molecular , Glucose-6-Fosfatase/metabolismo , Glucofosfatos/metabolismo , Glucosiltransferases/genética , Lactococcus lactis/genética , Fosfatos/metabolismo , Trealose/biossíntese , Leveduras/genética
3.
Appl Microbiol Biotechnol ; 103(13): 5379-5390, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31069486

RESUMO

Trehalose is a nonreducing disaccharide, and it plays an intracellular protective role in organisms under various stress conditions. In this study, the trehalose synthesis and its protective role in Pleurotus ostreatus were investigated. As a signal in metabolic regulation, reactive oxygen species (ROS) accumulated in the mycelia of P. ostreatus under heat stress (HS). Furthermore, mycelial growth was significantly inhibited, and the malondialdehyde (MDA) level significantly increased under HS. First, exogenous addition of H2O2 inhibited mycelial growth and elevated the MDA level, while N-acetyl cysteine (NAC) and vitamin C (VC) reduced the MDA level and recovered mycelial growth under HS by scavenging ROS. These results indicated that the mycelial radial growth defect under HS might be partly caused by ROS accumulation. Second, adding NAC and VC to the media resulted in rescued trehalose accumulation, which indicated that ROS has an effect on inducing trehalose synthesis. Third, the mycelial growth was recovered by addition of trehalose to the media after HS, and the MDA level was reduced. This effect was further verified by the overexpression of genes for trehalose-6-phosphate synthase (TPS) and neutral trehalase (NTH), which led to increased and reduced trehalose content, respectively. In addition, adding validamycin A (NTH inhibitor) to the media promoted trehalose accumulation and the recovered mycelial growth after HS. In conclusion, trehalose production was partly induced by ROS accumulation in the mycelia under HS, and the accumulated trehalose could promote the recovery of growth after HS, partly by reducing the MDA level in the mycelia.


Assuntos
Resposta ao Choque Térmico , Pleurotus/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Trealose/biossíntese , Ácido Ascórbico/farmacologia , Cisteína/farmacologia , Glucosiltransferases/genética , Temperatura Alta , Malondialdeído/análise , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Estresse Oxidativo , Pleurotus/metabolismo , Trealase/genética
4.
Protist ; 168(6): 649-662, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29100111

RESUMO

The non-reducing disaccharide trehalose can serve as a protectant against a range of environmental stressors, such as heat, cold, or dehydration, in both prokaryotes and eukaryotes, with the exception of vertebrates. Here, we analyzed trehalose metabolism in the facultatively parasitic organism Acanthamoeba castellanii, known to respond to unfavorable external conditions by forming two resistant stages: a cyst, produced in the case of chronic stress, and a pseudocyst, formed in reaction to acute stress. The possible role of trehalose in the resistant stages was investigated using a combination of bioinformatic, molecular biological and biochemical approaches. Genes for enzymes from a widespread trehalose-6-synthase-trehalose-6-phosphate phosphatase (TPS-TPP) pathway and a prokaryotic trehalose synthase (TreS) pathway were identified. The expression patterns of the genes during encystation and pseudocyst formation were analyzed and correlated with the time course of cellular trehalose content determined mass spectrometrically. The data clearly demonstrate fundamental differences between encystation and pseudocyst formation at the level of cellular metabolism.


Assuntos
Acanthamoeba castellanii/genética , Genoma de Protozoário , Proteínas de Protozoários/genética , Trealose/biossíntese , Acanthamoeba castellanii/metabolismo , Redes e Vias Metabólicas , Filogenia , Proteínas de Protozoários/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Protozoário/genética , RNA de Protozoário/metabolismo
5.
Cell Chem Biol ; 23(2): 278-289, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-27028886

RESUMO

Mycobacteria synthesize a variety of structurally related glycolipids with major biological functions. Common themes have emerged for the biosynthesis of these glycolipids, including several families of proteins. Genes encoding these proteins are usually clustered on bacterial chromosomal islets dedicated to the synthesis of one glycolipid family. Here, we investigated the function of a cluster of five genes widely distributed across non-tuberculous mycobacteria. Using defined mutant analysis and in-depth structural characterization of glycolipids from wild-type or mutant strains of Mycobacterium smegmatis and Mycobacterium abscessus, we established that they are involved in the formation of trehalose polyphleates (TPP), a family of compounds originally described in Mycobacterium phlei. Comparative genomics and lipid analysis of strains distributed along the mycobacterial phylogenetic tree revealed that TPP is synthesized by a large number of non-tuberculous mycobacteria. This work unravels a novel glycolipid biosynthetic pathway in mycobacteria and extends the spectrum of bacteria that produce TPP.


Assuntos
Glicolipídeos/biossíntese , Mycobacterium/classificação , Mycobacterium/metabolismo , Filogenia , Trealose/análogos & derivados , Trealose/biossíntese , Glicolipídeos/química , Glicolipídeos/genética , Mycobacterium/química , Mycobacterium/genética , Trealose/química
6.
Cell Chem Biol ; 23(2): 207-209, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26971870

RESUMO

When it comes to lipid diversity, no bacterial genus approaches Mycobacterium. In this issue of Cell Chemical Biology, Burbaud et al. (2016) provide a multi-genic working model for the biosynthesis of trehalose polyphleate (TPP), one of the largest known lipids in mycobacteria. They demonstrate that this lipid is made by diverse mycobacterial species, including those of medical importance.


Assuntos
Lipídeos/biossíntese , Mycobacterium , Lipídeos de Membrana , Infecções por Mycobacterium , Mycobacterium bovis , Mycobacterium tuberculosis , Trealose/biossíntese
7.
Biochim Biophys Acta ; 1850(1): 13-21, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25277548

RESUMO

BACKGROUND: Mycobacterium tuberculosis is a pathogenic prokaryote adapted to survive in hostile environments. In this organism and other Gram-positive actinobacteria, the metabolic pathways of glycogen and trehalose are interconnected. RESULTS: In this work we show the production, purification and characterization of recombinant enzymes involved in the partitioning of glucose-1-phosphate between glycogen and trehalose in M. tuberculosis H37Rv, namely: ADP-glucose pyrophosphorylase, glycogen synthase, UDP-glucose pyrophosphorylase and trehalose-6-phosphate synthase. The substrate specificity, kinetic parameters and allosteric regulation of each enzyme were determined. ADP-glucose pyrophosphorylase was highly specific for ADP-glucose while trehalose-6-phosphate synthase used not only ADP-glucose but also UDP-glucose, albeit to a lesser extent. ADP-glucose pyrophosphorylase was allosterically activated primarily by phosphoenolpyruvate and glucose-6-phosphate, while the activity of trehalose-6-phosphate synthase was increased up to 2-fold by fructose-6-phosphate. None of the other two enzymes tested exhibited allosteric regulation. CONCLUSIONS: Results give information about how the glucose-1-phosphate/ADP-glucose node is controlled after kinetic and regulatory properties of key enzymes for mycobacteria metabolism. GENERAL SIGNIFICANCE: This work increases our understanding of oligo and polysaccharides metabolism in M. tuberculosis and reinforces the importance of the interconnection between glycogen and trehalose biosynthesis in this human pathogen.


Assuntos
Glucofosfatos/metabolismo , Glicogênio/biossíntese , Redes e Vias Metabólicas , Mycobacterium tuberculosis/metabolismo , Trealose/biossíntese , Regulação Alostérica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Glucose-1-Fosfato Adenililtransferase/genética , Glucose-1-Fosfato Adenililtransferase/metabolismo , Glucose-6-Fosfato/metabolismo , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Glicogênio Sintase/genética , Glicogênio Sintase/metabolismo , Cinética , Modelos Biológicos , Mycobacterium tuberculosis/enzimologia , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , UTP-Glucose-1-Fosfato Uridililtransferase/genética , UTP-Glucose-1-Fosfato Uridililtransferase/metabolismo
8.
FEBS J ; 281(3): 825-41, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24616920

RESUMO

In this article, we aim to find an explanation for the surprisingly thin line, with regard to temperature, between cell growth, growth arrest and ultimately loss of cell viability. To this end, we used an integrative approach including both experimental and modelling work. We measured the short- and long-term effects of increases in growth temperature from 28 °C to 37, 39, 41, 42 or 43 °C on the central metabolism of Saccharomyces cerevisiae. Based on the experimental data, we developed a kinetic mathematical model that describes the metabolic and energetic changes in growing bakers' yeast when exposed to a specific temperature upshift. The model includes the temperature dependence of core energy-conserving pathways, trehalose synthesis, protein synthesis and proteolysis. Because our model focuses on protein synthesis and degradation, the net result of which is important in determining the cell's capacity to grow, the model includes growth, i.e. glucose is consumed and biomass and adenosine nucleotide cofactors are produced. The model reproduces both the observed initial metabolic response and the subsequent relaxation into a new steady-state, compatible with the new ambient temperature. In addition, it shows that the energy consumption for proteome reprofiling may be a major determinant of heat-induced growth arrest and subsequent recovery or cell death.


Assuntos
Adaptação Fisiológica , Regulação Fúngica da Expressão Gênica , Modelos Biológicos , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Técnicas de Cultura Celular por Lotes , Morte Celular , Proliferação de Células , Metabolismo Energético , Perfilação da Expressão Gênica , Temperatura Alta/efeitos adversos , Cinética , Viabilidade Microbiana , Fosforilação Oxidativa , Biossíntese de Proteínas , Estabilidade Proteica , Proteólise , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/biossíntese , Trealose/biossíntese
9.
J Cell Physiol ; 229(9): 1245-55, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24446217

RESUMO

Trehalose-6-phosphate phosphatase (TPP) catalyzes the final step in the biosynthesis of the anti-stress sugar trehalose. An 82 kDa TPP enzyme was isolated from Candida utilis with 61% yield and 43-fold purification. The protein sequence, determined by N-terminal sequencing and MALDI-TOF analysis, showed significant homology with known TPP sequences from related organisms. The full length gene sequence of TPP of C. utilis was identified using rapid amplification of cDNA ends-PCR reaction (RACE-PCR). The gene was cloned and expressed in Escherichia coli BL21. Recombinant TPP enzyme was isolated using affinity chromatography. CD spectroscopy and steady-state fluorescence revealed that the structural and conformational aspects were identical in both native and recombinant forms. The biochemical properties of the two forms were also similar. Km was determined to be ~0.8 mM. Optimum temperature and pH were found to be 30 °C and 8.5, respectively. Activity was dependent on the presence of divalent cations and inhibited by metal chelators. Methylation-mediated regulation of TPP enzyme and its effect on the overall survival of the organism under stress were investigated. The results indicated that enhancement of TPP activity by methylation at the Cysteine residues increased resistance of Candida cells against thermal stress. This work involves extensive investigations toward understanding the physico-chemical properties of the first TPP enzyme from any yeast strain. The mechanism by which methylation regulates its activity has also been studied. A correlation between regulation of trehalose synthesis and survivability of the organism under thermal stress was established.


Assuntos
Candida/enzimologia , Proteínas Fúngicas/metabolismo , Resposta ao Choque Térmico , Monoéster Fosfórico Hidrolases/metabolismo , Trealose/biossíntese , Sequência de Aminoácidos , Candida/genética , Quelantes/farmacologia , Cromatografia de Afinidade , Dicroísmo Circular , Clonagem Molecular , Inibidores Enzimáticos/farmacologia , Proteínas Fúngicas/antagonistas & inibidores , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Metilação , Dados de Sequência Molecular , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Monoéster Fosfórico Hidrolases/química , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/isolamento & purificação , Conformação Proteica , Processamento de Proteína Pós-Traducional , Proteínas Recombinantes/metabolismo , Espectrometria de Fluorescência , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Temperatura
10.
ISME J ; 8(3): 636-649, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24048226

RESUMO

We investigated the mechanisms of osmoadaptation in the order Halobacteriales, with special emphasis on Haladaptatus paucihalophilus, known for its ability to survive in low salinities. H. paucihalophilus genome contained genes for trehalose synthesis (trehalose-6-phosphate synthase/trehalose-6-phosphatase (OtsAB pathway) and trehalose glycosyl-transferring synthase pathway), as well as for glycine betaine uptake (BCCT family of secondary transporters and QAT family of ABC transporters). H. paucihalophilus cells synthesized and accumulated ∼1.97-3.72 µmol per mg protein of trehalose in a defined medium, with its levels decreasing with increasing salinities. When exogenously supplied, glycine betaine accumulated intracellularly with its levels increasing at higher salinities. RT-PCR analysis strongly suggested that H. paucihalophilus utilizes the OtsAB pathway for trehalose synthesis. Out of 83 Halobacteriales genomes publicly available, genes encoding the OtsAB pathway and glycine betaine BCCT family transporters were identified in 38 and 60 genomes, respectively. Trehalose (or its sulfonated derivative) production and glycine betaine uptake, or lack thereof, were experimentally verified in 17 different Halobacteriales species. Phylogenetic analysis suggested that trehalose synthesis is an ancestral trait within the Halobacteriales, with its absence in specific lineages reflecting the occurrence of gene loss events during Halobacteriales evolution. Analysis of multiple culture-independent survey data sets demonstrated the preference of trehalose-producing genera to saline and low salinity habitats, and the dominance of genera lacking trehalose production capabilities in permanently hypersaline habitats. This study demonstrates that, contrary to current assumptions, compatible solutes production and uptake represent a common mechanism of osmoadaptation within the Halobacteriales.


Assuntos
Betaína/metabolismo , Halobacteriales/fisiologia , Proteínas de Bactérias/metabolismo , Ecossistema , Perfilação da Expressão Gênica , Glucosiltransferases/metabolismo , Halobacteriales/classificação , Halobacteriales/genética , Proteínas de Membrana Transportadoras/genética , Dados de Sequência Molecular , Filogenia , Salinidade , Cloreto de Sódio/metabolismo , Trealose/biossíntese
11.
PLoS One ; 7(9): e45494, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23029052

RESUMO

BACKGROUND: Quercetin is a naturally occurring flavonol with antioxidant, anticancer and anti-ageing properties. In this study we aimed to identify genes differentially expressed in yeast cells treated with quercetin and its role in oxidative stress protection. METHODS: A microarray analysis was performed to characterize changes in the transcriptome and the expression of selected genes was validated by RT-qPCR. Biological processes significantly affected were identified by using the FUNSPEC software and their relevance in H(2)O(2) resistance induced by quercetin was assessed. RESULTS: Genes associated with RNA metabolism and ribosome biogenesis were down regulated in cells treated with quercetin, whereas genes associated with carbohydrate metabolism, endocytosis and vacuolar proteolysis were up regulated. The induction of genes related to the metabolism of energy reserves, leading to the accumulation of the stress protectant disaccharide trehalose, and the activation of the cell wall integrity pathway play a key role in oxidative stress resistance induced by quercetin. CONCLUSIONS: These results suggest that quercetin may act as a modulator of cell signaling pathways related to carbohydrate metabolism and cell integrity to exert its protective effects against oxidative stress.


Assuntos
Antioxidantes/farmacologia , Parede Celular/metabolismo , Estresse Oxidativo , Quercetina/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Trealose/biossíntese , Actinas/metabolismo , Antioxidantes/química , Perfilação da Expressão Gênica , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Glicogênio/metabolismo , Glicólise/efeitos dos fármacos , Peróxido de Hidrogênio/farmacologia , Quercetina/química , Saccharomyces cerevisiae/genética , Transdução de Sinais/efeitos dos fármacos
12.
Carbohydr Res ; 361: 175-81, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23026712

RESUMO

Trehalose metabolism plays a central role in various stress responses in yeasts. Methylation dependant enhancement of trehalose synthesis has been reported from yeast Saccharomyces cerevisiae. In order to establish the role of methylation on trehalose metabolism in yeast, it was further investigated in Candida utilis. Universal methyl group donor, S-adenosyl-l-methionine (AdoMet) and its inhibitor, oxidized adenosine (Adox) were used to study the effect of methylation on trehalose metabolism in C. utilis. Treatment of early stationary phase cells of C. utilis with AdoMet and Adox exhibited increase in both intracellular metabolite levels and activities of the trehalose synthesizing enzymes, trehalose-6-phosphate synthase (TPS) and trehalose phosphate phosphatase (TPP). Among the intracellular metabolites studied, trehalose levels were enhanced in presence of AdoMet which correlated with the increasing levels of trehalose synthesizing enzymes. TPS was purified in presence of AdoMet and Adox, following an established protocol reported from this laboratory. Differences in the mobility of control TPS, methylated TPS, and methylation-inhibited TPS during acidic native gel electrophoresis confirmed the occurrence of induced methylation. MALDI-TOF analysis of trypsin-digested samples of the same further strengthened the presence of methylation in TPS. The data presented in this paper strongly indicate a positive role of methylation on trehalose synthesis which finally leads to enhanced trehalose production during the stationary growth phase of C. utilis.


Assuntos
Candida/metabolismo , Trealose/biossíntese , Candida/citologia , Glucosiltransferases/isolamento & purificação , Glucosiltransferases/metabolismo , Metilação , Fatores de Tempo , Trealose/química , Trealose/metabolismo
13.
PLoS One ; 6(9): e23784, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21912644

RESUMO

Ramlibacter tataouinensis TTB310(T) (strain TTB310), a betaproteobacterium isolated from a semi-arid region of South Tunisia (Tataouine), is characterized by the presence of both spherical and rod-shaped cells in pure culture. Cell division of strain TTB310 occurs by the binary fission of spherical "cyst-like" cells ("cyst-cyst" division). The rod-shaped cells formed at the periphery of a colony (consisting mainly of cysts) are highly motile and colonize a new environment, where they form a new colony by reversion to cyst-like cells. This unique cell cycle of strain TTB310, with desiccation tolerant cyst-like cells capable of division and desiccation sensitive motile rods capable of dissemination, appears to be a novel adaptation for life in a hot and dry desert environment. In order to gain insights into strain TTB310's underlying genetic repertoire and possible mechanisms responsible for its unusual lifestyle, the genome of strain TTB310 was completely sequenced and subsequently annotated. The complete genome consists of a single circular chromosome of 4,070,194 bp with an average G+C content of 70.0%, the highest among the Betaproteobacteria sequenced to date, with total of 3,899 predicted coding sequences covering 92% of the genome. We found that strain TTB310 has developed a highly complex network of two-component systems, which may utilize responses to light and perhaps a rudimentary circadian hourglass to anticipate water availability at the dew time in the middle/end of the desert winter nights and thus direct the growth window to cyclic water availability times. Other interesting features of the strain TTB310 genome that appear to be important for desiccation tolerance, including intermediary metabolism compounds such as trehalose or polyhydroxyalkanoate, and signal transduction pathways, are presented and discussed.


Assuntos
Adaptação Fisiológica/genética , Divisão Celular/genética , Comamonadaceae/citologia , Comamonadaceae/fisiologia , Clima Desértico , Genoma Bacteriano , Genômica , Adaptação Fisiológica/efeitos da radiação , Metabolismo dos Carboidratos/genética , Metabolismo dos Carboidratos/efeitos da radiação , Divisão Celular/efeitos da radiação , Membrana Celular/metabolismo , Membrana Celular/efeitos da radiação , Movimento Celular/genética , Movimento Celular/efeitos da radiação , Forma Celular/genética , Forma Celular/efeitos da radiação , Ritmo Circadiano/genética , Ritmo Circadiano/efeitos da radiação , Comamonadaceae/enzimologia , Comamonadaceae/genética , Reparo do DNA/genética , Reparo do DNA/efeitos da radiação , DNA Bacteriano/genética , Espaço Extracelular/genética , Espaço Extracelular/metabolismo , Espaço Extracelular/efeitos da radiação , Ácidos Graxos/metabolismo , Hidrólise/efeitos da radiação , Luz , Fluidez de Membrana/genética , Fluidez de Membrana/efeitos da radiação , Lipídeos de Membrana/metabolismo , Pressão Osmótica/efeitos da radiação , Estresse Oxidativo/genética , Estresse Oxidativo/efeitos da radiação , Polissacarídeos Bacterianos/biossíntese , Polissacarídeos Bacterianos/metabolismo , Transporte Proteico/genética , Transporte Proteico/efeitos da radiação , Análise de Sequência de DNA , Transdução de Sinais/genética , Transdução de Sinais/efeitos da radiação , Trealose/biossíntese , Trealose/metabolismo
15.
Environ Microbiol ; 13(3): 551-62, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21054739

RESUMO

Compatible solutes are a functional group of small, highly soluble organic molecules that demonstrate compatibility in high amounts with cellular metabolism. The accumulation of compatible solutes is often observed during the acclimation of organisms to adverse environmental conditions, particularly to salt and drought stress. Among cyanobacteria, sucrose, trehalose, glucosylglycerol and glycine betaine are used as major compatible solutes. Interestingly, a close correlation has been discovered between the final salt tolerance limit and the primary compatible solute in these organisms. In addition to the dominant compatible solutes, many strains accumulate mixtures of these compounds, including minor compounds such as glucosylglycerate or proline as secondary or tertiary solutes. In particular, the accumulation of sucrose and trehalose results in an increase in tolerance to general stresses such as desiccation and high temperatures. During recent years, the biochemical and molecular basis of compatible solute accumulation has been characterized using cyanobacterial model strains that comprise different salt tolerance groups. Based on these data, the distribution of genes involved in compatible solute synthesis among sequenced cyanobacterial genomes is reviewed, and thereby, the major compatible solutes and potential salt tolerance of these strains can be predicted. Knowledge regarding cyanobacterial salt tolerance is not only useful to characterize strain-specific adaptations to ecological niches, but it can also be used to generate cells with increased tolerance to adverse environmental conditions for biotechnological purposes.


Assuntos
Cianobactérias/metabolismo , Adaptação Fisiológica , Betaína/metabolismo , Cianobactérias/química , Glucosídeos/biossíntese , Prolina/biossíntese , Tolerância ao Sal , Sacarose/metabolismo , Trealose/biossíntese
16.
Appl Environ Microbiol ; 76(16): 5452-62, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20581190

RESUMO

The foliar pathogen Pseudomonas syringae pv. syringae exhibits an exceptional ability to survive on asymptomatic plants as an epiphyte. Intermittent wetting events on plants lead to osmotic and matric stresses which must be tolerated for survival as an epiphyte. In this study, we have applied bioinformatic, genetic, and biochemical approaches to address water stress tolerance in P. syringae pv. syringae strain B728a, for which a complete genome sequence is available. P. syringae pv. syringae B728a is able to produce the compatible solutes betaine, ectoine, N-acetylglutaminylglutamine amide (NAGGN), and trehalose. Analysis of osmolyte profiles of P. syringae pv. syringae B728a under a variety of in vitro and in planta conditions reveals that the osmolytes differentially contribute to water stress tolerance in this species and that they interact at the level of transcription to yield a hierarchy of expression. While the interruption of a putative gene cluster coding for NAGGN biosynthesis provided the first experimental evidence of the NAGGN biosynthetic pathway, application of this knockout strain and also a gfp reporter gene fusion strain demonstrated the small contribution of NAGGN to cell survival and desiccation tolerance of P. syringae pv. syringae B728a under in planta conditions. Additionally, detailed investigation of ectC, an orphan of the ectoine cluster (lacking the ectA and ectB homologs), revealed its functionality and that ectoine production could be detected in NaCl-amended cultures of P. syringae pv. syringae B728a to which sterilized leaves of Syringa vulgaris had been added.


Assuntos
Vias Biossintéticas/genética , Genoma Bacteriano , Pressão Osmótica , Pseudomonas syringae/genética , Pseudomonas syringae/fisiologia , Estresse Fisiológico , Diamino Aminoácidos/biossíntese , Betaína/metabolismo , Dipeptídeos/biossíntese , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Viabilidade Microbiana , Família Multigênica , Mutagênese Insercional , Folhas de Planta/microbiologia , Syringa/microbiologia , Trealose/biossíntese
17.
J Biol Chem ; 284(40): 27229-34, 2009 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-19620241

RESUMO

In yeast, trehalose is synthesized by a multimeric enzymatic complex: TPS1 encodes trehalose 6-phosphate synthase, which belongs to a complex that is composed of at least three other subunits, including trehalose 6-phosphate phosphatase Tps2 and the redundant regulatory subunits Tps3 and Tsl1. The product of the TPS1 gene plays an essential role in the control of the glycolytic pathway by restricting the influx of glucose into glycolysis. In this paper, we investigated whether the trehalose synthesis pathway could be involved in the control of the other energy-generating pathway: oxidative phosphorylation. We show that the different mutants of the trehalose synthesis pathway (tps1Delta, tps2Delta, and tps1,2Delta) exhibit modulation in the amount of respiratory chains, in terms of cytochrome content and maximal respiratory activity. Furthermore, these variations in mitochondrial enzymatic content are positively linked to the intracellular concentration in cAMP that is modulated by Tps1p through hexokinase2. This is the first time that a pathway involved in sugar storage, i.e. trehalose, is shown to regulate the mitochondrial enzymatic content.


Assuntos
AMP Cíclico/metabolismo , Hexoquinase/metabolismo , Mitocôndrias/metabolismo , Saccharomyces cerevisiae/metabolismo , Trealose/biossíntese , Citocromos/metabolismo , Transporte de Elétrons , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Cinética , Mutação , Fosforilação , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Temperatura
18.
Plant Mol Biol ; 64(4): 371-86, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17453154

RESUMO

Most organisms naturally accumulating trehalose upon stress produce the sugar in a two-step process by the action of the enzymes trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP). Transgenic plants overexpressing TPS have shown enhanced drought tolerance in spite of minute accumulation of trehalose, amounts believed to be too small to provide a protective function. However, overproduction of TPS in plants has also been found combined with pleiotropic growth aberrations. This paper describes three successful strategies to circumvent such growth defects without loosing the improved stress tolerance. First, we introduced into tobacco a double construct carrying the genes TPS1 and TPS2 (encoding TPP) from Saccharomyces cerevisiae. Both genes are regulated by an Arabidopsis RuBisCO promoter from gene AtRbcS1A giving constitutive production of both enzymes. The second strategy involved stress-induced expression by fusing the coding region of ScTPS1 downstream of the drought-inducible Arabidopsis AtRAB18 promoter. In transgenic tobacco plants harbouring genetic constructs with either ScTPS1 alone, or with ScTPS1 and ScTPS2 combined, trehalose biosynthesis was turned on only when the plants experienced stress. The third strategy involved the use of AtRbcS1A promoter together with a transit peptide in front of the coding sequence of ScTPS1, which directed the enzyme to the chloroplasts. This paper confirms that the enhanced drought tolerance depends on unknown ameliorated water retention as the initial water status is the same in control and transgenic plants and demonstrates the influence of expression of heterologous trehalose biosynthesis genes on Arabidopsis root development.


Assuntos
Glucosiltransferases/genética , Nicotiana/genética , Monoéster Fosfórico Hidrolases/genética , Plantas Geneticamente Modificadas/fisiologia , Proteínas de Saccharomyces cerevisiae/genética , Trealose/biossíntese , Água/metabolismo , Arabidopsis/anatomia & histologia , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Cloroplastos/metabolismo , Engenharia Genética , Glucosiltransferases/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Plantas Geneticamente Modificadas/anatomia & histologia , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Regiões Promotoras Genéticas , Ribulose-Bifosfato Carboxilase/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Nicotiana/anatomia & histologia , Nicotiana/crescimento & desenvolvimento , Proteínas rab de Ligação ao GTP/genética
19.
Biotechnol Lett ; 29(2): 213-7, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17151959

RESUMO

In mineral salts medium, supplementing with betaine in combination with increased production of endogenous osmoprotectant from a second copy of the trehalose biosynthetic genes (otsBA) improved growth of E. coli and increased the MIC for xylose, glucose, sodium lactate and NaCl. With these compounds, this combination was more effective than either betaine or trehalose alone. With succinate, this combination was no more effective than betaine alone. Neither approach improved tolerance to ethanol. A combination of betaine and increased trehalose may improve strain productivity for many bioproducts by promoting growth in the presence of high sugar concentrations.


Assuntos
Betaína/farmacologia , Escherichia coli/efeitos dos fármacos , Trealose/biossíntese , Meios de Cultura/farmacologia , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Glucose/farmacologia , Pressão Osmótica/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Lactato de Sódio/farmacologia , Xilose/farmacologia
20.
Extremophiles ; 9(1): 29-36, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15455210

RESUMO

The genes for trehalose synthesis in Thermus thermophilus RQ-1, namely otsA [trehalose-phosphate synthase (TPS)], otsB [trehalose-phosphate phosphatase (TPP)], and treS [trehalose synthase (maltose converting) (TreS)] genes are structurally linked. The TPS/TPP pathway plays a role in osmoadaptation, since mutants unable to synthesize trehalose via this pathway were less osmotolerant, in trehalose-deprived medium, than the wild-type strain. The otsA and otsB genes have now been individually cloned and overexpressed in Escherichia coli and the corresponding recombinant enzymes purified. The apparent molecular masses of TPS and TPP were 52 and 26 kDa, respectively. The recombinant TPS utilized UDP-glucose, TDP-glucose, ADP-glucose, or GDP-glucose, in this order as glucosyl donors, and glucose-6-phosphate as the glucosyl acceptor to produce trehalose-6-phosphate (T6P). The recombinant TPP catalyzed the dephosphorylation of T6P to trehalose. This enzyme also dephosphorylated G6P, and this activity was enhanced by NDP-glucose. TPS had an optimal activity at about 98 degrees C and pH near 6.0; TPP had a maximal activity near 70 degrees C and at pH 7.0. The enzymes were extremely thermostable: at 100 degrees C, TPS had a half-life of 31 min, and TPP had a half-life of 40 min. The enzymes did not require the presence of divalent cations for activity; however, the presence of Co2+ and Mg2+ stimulates both TPS and TPP. This is the first report of the characterization of TPS and TPP from a thermophilic organism.


Assuntos
Glucosiltransferases/química , Monoéster Fosfórico Hidrolases/química , Fosfatos Açúcares/química , Thermus thermophilus/enzimologia , Trealose/análogos & derivados , Trealose/biossíntese , Difosfato de Adenosina/química , Catálise , Clonagem Molecular , Cobalto/química , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Glucose/química , Guanosina Difosfato/química , Temperatura Alta , Concentração de Íons de Hidrogênio , Cinética , Magnésio/química , Mutação , Fosforilação , Proteínas Recombinantes/química , Temperatura , Fatores de Tempo , Trealose/química , Difosfato de Uridina/química , Uridina Difosfato Glucose/química
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