RESUMO
Glucoamylases (GAs) are one of the principal groups of enzymes involved in starch hydrolysis and belong to the glycosylhydrolase family. They are classified as exo-amylases due to their ability to hydrolyze α-1,4 glycosidic bonds from the non-reducing end of starch, maltooligosaccharides, and related substrates, releasing ß-D-glucose. Structurally, GAs possess a characteristic catalytic domain (CD) with an (α/α)6 fold and exhibit five conserved regions within this domain. The CD may or may not be linked to a non-catalytic domain with variable functions depending on its origin. GAs are versatile enzymes with diverse applications in food, biofuel, bioplastic and other chemical industries. Although fungal GAs are commonly employed for these purposes, they have limitations such as their low thermostability and an acidic pH requirement. Alternatively, GAs derived from prokaryotic organisms are a good option to save costs as they exhibit greater thermostability compared to fungal GAs. Moreover, a group of cold-adapted GAs from psychrophilic organisms demonstrates intriguing properties that make them suitable for application in various industries. This review provides a comprehensive overview of the structural and sequential properties as well as biotechnological applications of GAs in different industrial processes.
Assuntos
Amilases , Glucana 1,4-alfa-Glucosidase , Biocombustíveis , Biotecnologia , AmidoRESUMO
Ruminants enable the conversion of indigestible plant material into animal consumables, including dairy products, meat, and valuable fibers. Microbiome research is gaining popularity in livestock species because it aids in the knowledge of illnesses and efficiency processes in animals. In this study, we use WGS metagenomic data to thoroughly characterize the ruminal ecosystem of cows to infer positive and negative livestock traits determined by the microbiome. The rumen of cows from Argentina were described by combining different gene biomarkers, pathways composition and taxonomic information. Taxonomic characterization indicated that the two major phyla were Bacteroidetes and Firmicutes; in third place, Proteobacteria was highly represented followed by Actinobacteria; Prevotella, and Bacteroides were the most abundant genera. Functional profiling of carbohydrate-active enzymes indicated that members of the Glycoside Hydrolase (GH) class accounted for 52.2 to 55.6% of the total CAZymes detected, among them the most abundant were the oligosaccharide degrading enzymes. The diversity of GH families found suggested efficient hydrolysis of complex biomass. Genes of multidrug, macrolides, polymyxins, beta-lactams, rifamycins, tetracyclines, and bacitracin resistance were found below 0.12% of relative abundance. Furthermore, the clustering analysis of genera and genes that correlated to methane emissions or feed efficiency, suggested that the cows analysed could be regarded as low methane emitters and clustered with high feed efficiency reference animals. Finally, the combination of bioinformatic analyses used in this study can be applied to assess cattle traits difficult to measure and guide enhanced nutrition and breeding methods.
Assuntos
Microbiota , Rúmen , Feminino , Bovinos , Animais , Microbiota/genética , Metagenoma , Bactérias , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Metano/metabolismo , Ração Animal , DietaRESUMO
Phosphoenolpyruvate carboxykinase (PEPCK) catalyses the reversible reaction of decarboxylation and phosphorylation of oxaloacetate (OAA) to generate phosphoenolpyruvate (PEP) and CO2 playing mainly a gluconeogenic role in green algae. We found two PEPCK isoforms in Chlamydomonas reinhardtii and we cloned, purified and characterised both enzymes. ChlrePEPCK1 is more active as decarboxylase than ChlrePEPCK2. ChlrePEPCK1 is hexameric and its activity is affected by citrate, phenylalanine and malate, while ChlrePEPCK2 is monomeric and it is regulated by citrate, phenylalanine and glutamine. We postulate that the two PEPCK isoforms found originate from alternative splicing of the gene or regulated proteolysis of the enzyme. The presence of these two isoforms would be part of a mechanism to finely regulate the biological activity of PEPCKs.
Assuntos
Chlamydomonas reinhardtii , Fosfoenolpiruvato , Chlamydomonas reinhardtii/genética , Fosfoenolpiruvato Carboxiquinase (ATP)/genética , Isoformas de Proteínas , Fenilalanina , CitratosRESUMO
Mesial temporal lobe epilepsy (MTLE) is one of the most common types of focal epilepsy in the adult population. MTLE is frequently associated with a specific histopathological lesion in the medial temporal structures, namely hippocampal sclerosis (HS). A significant proportion of patients with MTLE+HS have severe epilepsy, which is often resistant to clinical treatment. For these patients, surgical resection of the epileptogenic lesion can be performed. Our understanding of the underlying mechanisms leading to MTLE+HS has improved significantly over the past few decades. In this review, we aim to present and discuss the most recent findings regarding the genetic determinants of MTLE+HS. Furthermore, we will address studies about transcriptomics, proteomics, metabolomics, and epigenomic signatures of the tissue that is surgically removed from patients with refractory MTLE+HS and animal models of the disorder. We expect to provide an overview and a critical discussion of the findings, limitations, new approaches, and future directions for multi-omics studies in MTLE+HS.
Assuntos
Epilepsia do Lobo Temporal , Epilepsia , Adulto , Epilepsia/patologia , Epilepsia do Lobo Temporal/genética , Epilepsia do Lobo Temporal/patologia , Epilepsia do Lobo Temporal/cirurgia , Hipocampo/patologia , Humanos , Imageamento por Ressonância Magnética , Esclerose/patologiaRESUMO
Chlamydomonas reinhardtii is the best known unicellular green alga model which has long been used to investigate all kinds of cellular processes, including starch metabolism. Here we identified and characterized a novel enzyme, ChlreSEX4, orthologous to glucan phosphatase SEX4 from Arabidopsis thaliana, that is capable of binding and dephosphorylating amylopectin in vitro. We also reported that cysteine 224 and tryptophan 305 residues are critical for enzyme catalysis and substrate binding. Furthermore, we verified that ChlreSEX4 gene is expressed in vivo and that glucan phosphatase activity is measurable in Chlamydomonas protein extracts. In view of the results presented, we suggest ChlreSEX4 as a functional phosphoglucan phosphatase from C. reinhardtii. Our data obtained so far contribute to understanding the phosphoglucan phosphatases evolutionary process in the green lineage and their role in starch reversible phosphorylation. In addition, this allows to position Chlamydomonas as a potential tool to obtain starches with different degrees of phosphorylation for industrial or biotechnological purposes.
Assuntos
Chlamydomonas reinhardtii/metabolismo , Clorófitas/metabolismo , Glucanos/metabolismo , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Amilopectina/metabolismo , Chlamydomonas reinhardtii/química , Clorófitas/química , Glucanos/química , Modelos Moleculares , Fosforilação , Proteínas de Plantas/química , Especificidade por SubstratoRESUMO
Resumen En la actualidad se ha generalizado la administración de los inhibidores de la bomba de protones casi de manera universal, pero con especial insistencia en los pacientes hospitalizados. Su administración se ha considerado inocua y con efectos protectores; sin embargo, la administración indiscriminada de este grupo de fármacos tiene serias consecuencias para la salud.
Abstract Currently the use of proton pump inhibitors has become widespread almost universally but with special emphasis on hospitalized patients. Its use has been considered innocuous and with protective effects; however, the indiscriminate administration of this group of drugs has health consequences.
RESUMO
Ostreococcus tauri, the smallest free-living (non-symbiotic) eukaryote yet described, is a unicellular green alga of the Prasinophyceae family. It has a very simple cellular organization and presents a unique starch granule and chloroplast. However, its starch metabolism exhibits a complexity comparable to higher plants, with multiple enzyme forms for each metabolic reaction. Glucan phosphatases, a family of enzymes functionally conserved in animals and plants, are essential for normal starch or glycogen degradation in plants and mammals, respectively. Despite the importance of O. tauri microalgae in evolution, there is no information available concerning the enzymes involved in reversible phosphorylation of starch. Here, we report the molecular cloning and heterologous expression of the gene coding for a dual specific phosphatase from O. tauri (OsttaDSP), homologous to Arabidopsis thaliana LSF2. The recombinant enzyme was purified to electrophoretic homogeneity to characterize its oligomeric and kinetic properties accurately. OsttaDSP is a homodimer of 54.5 kDa that binds and dephosphorylates amylopectin. Also, we also determined that residue C162 is involved in catalysis and possibly also in structural stability of the enzyme. Our results could contribute to better understand the role of glucan phosphatases in the metabolism of starch in green algae.
Assuntos
Clorófitas/enzimologia , Glucanos/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Sequência de Aminoácidos , Clonagem Molecular , Dimerização , Cinética , Monoéster Fosfórico Hidrolases/química , Monoéster Fosfórico Hidrolases/genética , Fosforilação , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de AminoácidosRESUMO
Glucan phosphatases are essential for normal starch degradation in plants and glycogen metabolism in mammals. Here we develop two chromogenic methods for the detection of glucan phosphatase activity in situ after non denaturing poliacrylamide gel electrophoresis; one method uses pNPP and the second one applies BCIP/NBT. The assays are sensitive, fast, simple, reliable and cost-effective preventing the use of radioactive or fluorogenic compounds. Taking advantage of an efficient separation method combined with the reported assays it is possible to obtain information about oligomeric state of the active enzymes as well as to simultaneously detect glucan substrate binding and phosphatase activity.
Assuntos
Proteínas de Arabidopsis/química , Arabidopsis/enzimologia , Fosforilases/química , Coloração e Rotulagem/métodos , Eletroforese em Gel de Poliacrilamida/métodosRESUMO
Este estudo buscou estudar a influência da modalidade de reconto sobre a avaliação da compreensão leitora. Avaliaram-se 34 escolares do 2º ao 5º ano do Ensino Fundamental, sem queixas de leitura, agrupados em: 1) Grupo Reconto Oral: 19 crianças que recontaram oralmente texto narrativo e expositivo lidos; 2) Grupo Reconto Escrito: 15 que o fizeram por escrito. A análise dos recontos quantificou proposições de ideia central, detalhe, inferências e número de enlaces. Estabeleceu-se, também, o padrão de compreensão (3-0, do melhor para o pior desempenho). Resultados evidenciaram semelhanças entre as médias de desempenho dos grupos nas variáveis do reconto de texto narrativo. Para o expositivo, houve diferença para enlaces de primeiro nível (t = -2,114, p = 0,042), com maior média do Grupo reconto escrito. Concluiu-se, portanto, que a modalidade do reconto não influenciou a avaliação da compreensão de textos narrativos, mas o reconto escrito de textos expositivos favoreceu o aparecimento de enlaces entre ideias centrais.
The aim of the present study was to investigate the influence of the retelling strategy modality on the assessment of reading comprehension. Thirty-four 2nd-5th grade students (elementary school) without reading difficulties were evaluated and grouped as follows: Group 1. Oral retelling: students orally reconstructed narrative and expository texts they read (19 students); Group 2. Writing retelling: students retold these same stories in writing (15 students). The analysis conducted assessed retelling in terms of: proposition of central idea, details, inferences, and number of links. A performance reference standard (3-0) was also established from the best to the worst performance. The results obtained showed similarity between the average performance of the variables of the oral narrative text retelling groups. As for the expository texts, there were differences in the first level of links (t = -2.114, p = 0.042), and the highest average performance was found for the writing retelling group. It can be concluded that the retelling strategy modality did not influence the evaluation of the understanding of narrative texts, but the written retelling of expository texts influenced the connection of central ideas.
Assuntos
Humanos , Compreensão , LeituraRESUMO
Este estudo buscou estudar a influência da modalidade de reconto sobre a avaliação da compreensão leitora. Avaliaram-se 34 escolares do 2º ao 5º ano do Ensino Fundamental, sem queixas de leitura, agrupados em: 1) Grupo Reconto Oral: 19 crianças que recontaram oralmente texto narrativo e expositivo lidos; 2) Grupo Reconto Escrito: 15 que o fizeram por escrito. A análise dos recontos quantificou proposições de ideia central, detalhe, inferências e número de enlaces. Estabeleceu-se, também, o padrão de compreensão (3-0, do melhor para o pior desempenho). Resultados evidenciaram semelhanças entre as médias de desempenho dos grupos nas variáveis do reconto de texto narrativo. Para o expositivo, houve diferença para enlaces de primeiro nível (t = -2,114, p = 0,042), com maior média do Grupo reconto escrito. Concluiu-se, portanto, que a modalidade do reconto não influenciou a avaliação da compreensão de textos narrativos, mas o reconto escrito de textos expositivos favoreceu o aparecimento de enlaces entre ideias centrais.(AU)
The aim of the present study was to investigate the influence of the retelling strategy modality on the assessment of reading comprehension. Thirty-four 2nd-5th grade students (elementary school) without reading difficulties were evaluated and grouped as follows: Group 1. Oral retelling: students orally reconstructed narrative and expository texts they read (19 students); Group 2. Writing retelling: students retold these same stories in writing (15 students). The analysis conducted assessed retelling in terms of: proposition of central idea, details, inferences, and number of links. A performance reference standard (3-0) was also established from the best to the worst performance. The results obtained showed similarity between the average performance of the variables of the oral narrative text retelling groups. As for the expository texts, there were differences in the first level of links (t = -2.114, p = 0.042), and the highest average performance was found for the writing retelling group. It can be concluded that the retelling strategy modality did not influence the evaluation of the understanding of narrative texts, but the written retelling of expository texts influenced the connection of central ideas.(AU)
Assuntos
Humanos , Compreensão , LeituraRESUMO
Glycogen and starch, the major storage carbohydrate in most living organisms, result mainly from the action of starch or glycogen synthases (SS or GS, respectively, EC 2.4.1.21). SSIII from Arabidopsis thaliana is an SS isoform with a particular modular organization: the C-terminal highly conserved glycosyltransferase domain is preceded by a unique specific region (SSIII-SD) which contains three in tandem starch binding domains (SBDs, named D1, D2 and D3) characteristic of polysaccharide degrading enzymes. N-terminal SBDs have a probed regulatory role in SSIII activity, showing starch binding ability and modulating the catalytic properties of the enzyme. On the other hand, GS from Agrobacterium tumefaciens has a simple primary structure organization, characterized only by the highly conserved glycosyltransferase domain and lacking SBDs. To further investigate the functional role of A. thaliana SSIII-SD, three chimeric proteins were constructed combining the SBDs from A. thaliana with the GS from A. tumefaciens. Recombinant proteins were expressed in and purified to homogeneity from Escherichia coli cells in order to be kinetically characterized. Furthermore, we tested the ability to restore in vivo glycogen biosynthesis in transformed E. coli glgA(-) cells, deficient in GS. Results show that the D3-GS chimeric enzyme showed increased capacity of glycogen synthesis in vivo with minor changes in its kinetics parameters compared to GS.
Assuntos
Agrobacterium tumefaciens/enzimologia , Arabidopsis/enzimologia , Proteínas de Bactérias/metabolismo , Escherichia coli/enzimologia , Glicogênio Sintase/metabolismo , Proteínas de Plantas/metabolismo , Agrobacterium tumefaciens/genética , Arabidopsis/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Escherichia coli/genética , Expressão Gênica , Teste de Complementação Genética , Glicogênio/biossíntese , Glicogênio Sintase/química , Glicogênio Sintase/genética , Cinética , Engenharia Metabólica , Proteínas de Plantas/química , Proteínas de Plantas/genética , Estrutura Terciária de Proteína , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
Glycosyltransferases (GTs) are a ubiquitous group of enzymes that catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. Nucleotide-sugars, lipid phosphate sugars and phosphate sugars can act as activated donor molecules while acceptor substrates involve carbohydrates, proteins, lipids, DNA and also, numerous small molecules (i. e. antibiotics, flavonols, steroids). GTs enzyme families are very ancient. They are founded in all the three domains of life and display three different folds (named GT-A, GTB and GT-C) which are a variant of a common α/ß scaffold. In addition, several GTs contain an associated non-catalytic carbohydrate binding module (CBM) that could be critical for enzyme activity. This work reviews the current knowledge on the GTs structures and functions and highlights those enzymes that contain CBMs, particularly starch binding domains (SBDs). In addition, we also focus on A. thaliana starch synthase III enzyme, from the GT-5 family. This protein has a GT-B fold, and contains in its N-terminal region three in tandem SBDs, which are essential for the regulation of enzyme activity.
Assuntos
Proteínas de Arabidopsis/química , Glucosiltransferases/química , Glicosiltransferases/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Modelos Moleculares , Filogenia , Ligação Proteica , Dobramento de Proteína , Amido/metabolismoRESUMO
Temperature sensing is essential for the survival of living cells. The membrane-bound thermosensor DesK from Bacillus subtilis is a key representative of histidine kinases receptors able to remodel membrane lipid composition when the temperature drops below ~30°C. Although the receptor is well studied, a central issue remains: how does the compositional and functional diversity of the surrounding membrane modulate receptor function? Reconstituting full-length DesK into proteoliposomes of well-defined and controlled lipid composition represents a minimal synthetic approach to systematically address this question. Thus DesK has been reconstituted in a variety of phospholipid bilayers and its temperature-regulated autokinase activity determined as function of fatty acyl chain length, lipid head-group structure and phase preference. We show that the head group structure of lipids (both in vitro and in vivo) has little effect on DesK thermosensing, whereas properties determined by the acyl chain of lipids, such as membrane thickness and phase separation into coexisting lipid domains, exert a profound regulatory effect on kinase domain activation at low temperatures. These experiments suggest that the non-polar domain of glycerolipids is essential to regulate the allosteric structural transitions of DesK, by activating the autophosphorylation of the intracellular kinase domain in response to a decrease in temperature.
Assuntos
Bacillus subtilis/fisiologia , Proteínas de Bactérias/metabolismo , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Bacillus subtilis/metabolismo , Temperatura Baixa , Escherichia coli/genética , Histidina Quinase , Bicamadas Lipídicas , Fosfatidilcolinas/química , Fosfatidiletanolaminas/química , Fosfatidilgliceróis/química , Fosfolipídeos/química , Fosfolipídeos/metabolismo , Fosforilação , Proteínas Quinases/química , Proteínas Quinases/metabolismo , Proteolipídeos/química , Proteolipídeos/metabolismo , TemperaturaRESUMO
Recent findings demonstrate that alkaline/neutral invertases (A/N-Invs), enzymes that catalyze the breakdown of sucrose into glucose and fructose, are essential proteins in plant life. The fact that different isoforms are present in multiple locations makes them candidates for the coordination of metabolic processes. In the present study, we functionally characterized the encoding gene of a novel A/N-Inv (named A/N-InvC) from Arabidopsis, which localizes in mitochondria. A/N-InvC is expressed in roots, in aerial parts (shoots and leaves) and flowers. A detailed phenotypic analysis of knockout mutant plants (invc) reveals an impaired growth phenotype. Shoot growth was severely reduced, but root development was not affected as reported for A/N-InvA mutant (inva) plants. Remarkably, germination and flowering, two energy demanding processes, were the most affected stages. The effect of exogenous growth regulators led us to suggest that A/N-InvC may be modulating hormone balance in relation to the radicle emergence. We also show that oxygen consumption is reduced in inva and invc in comparison with wild-type plants, indicating that both organelle isoenzymes may play a fundamental role in mitochondrion functionality. Taken together, our results emphasize the involvement of mitochondrial A/N-Invs in developmental processes and uncover the possibility of playing different roles for the two isoforms located in the organelle.
Assuntos
Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Metabolismo Energético , Mitocôndrias/enzimologia , Proteínas Mitocondriais/metabolismo , beta-Frutofuranosidase/metabolismo , Ácido Abscísico/farmacologia , Arabidopsis/citologia , Arabidopsis/genética , Respiração Celular/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Flores/efeitos dos fármacos , Flores/fisiologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Germinação/efeitos dos fármacos , Giberelinas/farmacologia , Isoenzimas/genética , Isoenzimas/metabolismo , Mitocôndrias/efeitos dos fármacos , Proteínas Mitocondriais/genética , Mutação/genética , Fenótipo , Raízes de Plantas/citologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Sementes/efeitos dos fármacos , Sementes/enzimologia , Sementes/crescimento & desenvolvimento , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/enzimologia , beta-Frutofuranosidase/genéticaRESUMO
The mite Varroa destructor is an ectoparasite affecting honey bees worldwide. Synthetic acaricides have been among the principal tools available to beekeepers for its control, although several studies have shown its negative effects on honey bee physiology. Recent research suggests that those molecules strongly impact on immune signaling cascades and cellular immunity. In the present work, LC(50) in six-day-old bees were determined for the following acaricides: tau-fluvalinate, flumethrin, amitraz and coumaphos. According to this obtained value, a group of individuals was treated with each acaricide and then processed for qPCR analysis. Transcript levels for genes encoding antimicrobial peptides and immune-related proteins were assessed. Flumethrin increased the expression of hymenoptaecin when comparing treated and control bees. Significant differences were recorded between coumaphos and flumethrin treatments, while the first one reduced the expression of hymenoptaecin and abaecin, the last one up-regulated their expressions. No significant statistically changes were recorded in the expression levels of vitellogenin, lysozyme or glucose dehydrogenase among bees treated with acaricides and control bees. This work constitutes the first report, under laboratory conditions, about induction of immune related genes in response to synthetic miticides.
Assuntos
Acaricidas/farmacologia , Abelhas/crescimento & desenvolvimento , Abelhas/genética , Expressão Gênica/efeitos dos fármacos , Proteínas de Insetos/genética , Acaricidas/síntese química , Animais , Abelhas/efeitos dos fármacos , Abelhas/imunologia , Proteínas de Insetos/imunologiaRESUMO
The motive to attain a distinctive identity is sometimes thought to be stronger in, or even specific to, those socialized into individualistic cultures. Using data from 4,751 participants in 21 cultural groups (18 nations and 3 regions), we tested this prediction against our alternative view that culture would moderate the ways in which people achieve feelings of distinctiveness, rather than influence the strength of their motivation to do so. We measured the distinctiveness motive using an indirect technique to avoid cultural response biases. Analyses showed that the distinctiveness motive was not weaker-and, if anything, was stronger-in more collectivistic nations. However, individualism-collectivism was found to moderate the ways in which feelings of distinctiveness were constructed: Distinctiveness was associated more closely with difference and separateness in more individualistic cultures and was associated more closely with social position in more collectivistic cultures. Multilevel analysis confirmed that it is the prevailing beliefs and values in an individual's context, rather than the individual's own beliefs and values, that account for these differences.
Assuntos
Comparação Transcultural , Cultura , Individualidade , Autoimagem , Adolescente , África/etnologia , Europa (Continente)/etnologia , Feminino , Humanos , Masculino , Oriente Médio/etnologia , Motivação , Identificação Social , Valores Sociais , América do Sul/etnologiaRESUMO
Higher plants and cyanobacteria metabolize sucrose (Suc) by a similar set of enzymes. Suc synthase (SuS, A/UDP-glucose: D: -fructose 2-α-D: -glucosyl transferase) catalyzes a reversible reaction. However, it is in the cleavage of Suc that this enzyme plays an important role in vivo, providing sugar nucleotides for polysaccharide biosynthesis. In cyanobacteria, SuS occurrence has been reported in heterocyst-forming strains, where it was shown to be involved also in nitrogen fixation. We investigated the presence of sequences homologous to SuS-encoding genes (sus) in recently sequenced cyanobacterial genomes. In this work, we show for the first time the presence of SuS in unicellular cyanobacterium strains (Microcystis aeruginosa PCC 7806, Gloebacter violaceus PCC 7421, and Thermosynechococcus elongatus BP-1). After functional characterization of SuS encoding genes, we demonstrated an increase in their transcript levels after a salt treatment or hypoxic stress in M. aeruginosa and G. violaceus cells. Based on phylogenetic analysis and on the presence of sus homologs in the most recently radiated cyanobacterium strains, we propose that sus genes in unicellular cyanobacteria may have been acquired through horizontal gene transfer. Taken together, our data indicate that SuS acquisition by cyanobacteria might be related to open up new ecological niches.
Assuntos
Cianobactérias/enzimologia , Cianobactérias/genética , Glucosiltransferases/metabolismo , Cloreto de Sódio/metabolismo , Estresse Fisiológico/fisiologia , Sacarose/metabolismo , Adaptação Fisiológica/genética , Hipóxia Celular/fisiologia , Regulação Bacteriana da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Transferência Genética Horizontal , Genes Bacterianos , Glucosiltransferases/genética , Microcystis/enzimologia , Microcystis/genética , Salinidade , Plantas Tolerantes a Sal/enzimologia , Plantas Tolerantes a Sal/genética , Especificidade da EspécieRESUMO
La enfermedad de Chagas-Mazza es una enfermedad parasitaria causada por un protozoo flagelado, el Trypanosoma cruzi. Es una patología característica de Hispanoamérica y en la actualidad habría en el mundo más de 20 millones de infectados. Los objetivos del trabajo fueron: determinar la seroprevalencia en los pacientes con solicitud de serología para enfermedad de Chagas-Mazza y evaluar la situación epidemiológica y social de la población afectada. El trabajo es de tipo prospectivo, observacional y comprende el período entre julio de 2006 y julio de 2008. Se emplearon como técnicas de diagnóstico sobre muestras de suero: Hemaglutinación indirecta (HAI Chagatest, Wiener lab), enzimoinmunoensayo (Chagatest ELISA v 3.0 Wiener lab), ¡nmunofluorescencia indirecta (IFI con reactivos propios, utilizando antígenos y controles del Instituto Nacional de Parasitología "Dr. Mario Fatala Chabén"). Se consideraron positivas aquellas muestras con las que se obtuvo un resultado positivo en dos de las tres técnicas. Con el fin de optimizar la recolección de datos epidemiológicos se utilizó una estrategia multidisciplinaria que involucró a los médicos que solicitaban el estudio, a la Sala de Epidemiología, al servicio de Asistencia social y al laboratorio. Se obtuvo una seroprevalencia de 11,4% en el período estudiado, con la siguiente distribución por país de nacimiento: 47,8% Argentina, 43,5% Bolivia, 8,3% Paraguay y 0,4% Chile. Es evidente la importancia de los fenómenos migratorios en la región, entendiendo que la enfermedad de Chagas-Mazza representa una forma de movilización social. El 60,4% de los pacientes seropositivos tenían necesidades básicas insatisfechas, sólo el 30% de los entrevistados tenían estudios primarios completos. En cuanto a la percepción de la patología, se observa la aceptación de la enfermedad en referencia a que la padecen sus padres, otros familiares o allegados.
The Chagas-Mazza' disease is a parasitic disease caused by a flagellate protozoan, Trypanosoma cruzi. It is a pathology characteristic of Latin America and currently have over 20 million people infected all over the world. The objectives of this study were: to state the prevalence in patients with Chagas-Mazza ' disease infection application and to evaluate the epidemiological and social situation of the affected population. The work is prospective, observational, and covers the period July 2006 to July 2008. Were used as diagnostic techniques on serum samples: Indirect Hemagglutination (IHA Chagatest, Wiener lab), enzyme immunoassay (ELISA Chagatest Wiener lab v 3.0), immunofluorescence (IFI with their own reagents, antigens and controls using the National Institute of Parasitology "Dr. Mario Fatala Chabén"). Those samples were considered positive with which a positive result was obtained in two of the three techniques. To optimize the collection of epidemiological data used a multidisciplinary approach, involving physicians who requested the study to the Board of epidemiology, social work service and laboratory. We obtained a seroprevalence of 11.4% over the period studied, with the following distribution by country of birth: 47.8% Argentina, 43.5% Bolivia, 8.3% Paraguay and 0.4% Chile. Highlights the importance of migratory phenomena in the region, understanding that Chagas-Mazza' disease is a form of social mobilization. In 60.4% have unmet basic needs, only 30% of respondents have completed primary education. Regarding the perception of pathology is observed acceptance of the disease in reference to that suffered by their parents, other family members or relatives.
A doença de Chagas-Mazza é uma doença parasitaria causada por um protozoário flagelado, o Trypanosoma cruzi. E uma patologia característica de Hispanoamérica e na atualidade existiriam no mundo mais de 20 milhóes de infectados. Os objetivos do trabalho foram: determinar a soroprevalência nos pacientes com pedido de sorologia para doença de Chagas-Mazza e avaliar a situaçâo epidemiológica e social da populaçâo afetada. O trabalho é de tipo prospectivo, observacional e compreende o período entre julho de 2006 e julho de 2008. Foram utilizadas como técnicas de diagnóstico sobre amostras de soro: Hemaglutinaçâo indireta (HAI Chagatest, Wiener lab), enzimaimunoensaio (Chagatest ELISA v 3.0 Wiener lab), imunofluorescência indireta (IFI com reagentes próprios, utilizando antígenos e controles do Instituto Nacional de Parasitologia "Dr. Mario Fatala Chabén"). Foram consideradas positivas aquelas amostras com as quais foi obtido um resultado positivo em duas das très técnicas. Visando a otimizar a coleta de dados epidemiológicos, foi utilizada uma estratégia multidisciplinar que envolveu os médicos que solicitavam o estudo, a Sala de Epidemiologia, o serviço de Assistência Social e o laboratório. Foi obtida uma soroprevalência de 11,4%, no período estudado, com a seguinte distribuiçâo por país de nascimento: 47,8% Argentina, 43,5% Bolivia, 8,3% Paraguai e 0,4% Chile. E evidente a importancia dos fenómenos migratórios na regiâo, entendendo que a doença de Chagas-Mazza representa uma forma de mobilizaçâo social. 60,4% dos pacientes soropositivos tinham necessidades básicas insatisfeitas, só 30% dos entrevistados tinham finalizado o Primerio Grau. Quanto à percepçâo da patologia, observase a aceitaçâo da doença em referência a que é padecida por seus pais, outros familiares ou conhecidos.
Assuntos
Humanos , Doença de Chagas , Estudos Soroepidemiológicos , Doença de Chagas/epidemiologia , Epidemiologia , Estudo Observacional , Estudos Prospectivos , Trypanosoma cruzi/parasitologiaRESUMO
Two phosphoenolpyruvate carboxykinase (PEPCK, EC 4.1.1.49) isoforms of 74 and 65 kDa were found to coexist in vivo in pineapple leaves, a constitutive Crassulacean Acid Metabolism plant. The 65 kDa form was not the result of proteolytic cleavage of the larger form since extraction methods reported to prevent PEPCK proteolysis in other plant tissues failed to yield a single immunoreactive PEPCK polypeptide in leaf extracts. In this work, the smaller form of 65 kDa was purified to homogeneity and physically and kinetically characterized and showed parameters compatible with a fully active enzyme. The specific activity was nearly twice higher for decarboxylation of oxaloacetate when compared to carboxylation of phosphoenolpyruvate. Kinetic parameters fell within the range of those estimated for other plant PEPCKs. Its activity was affected by several metabolites, as shown by inhibition by 3-phosphoglycerate, citrate, malate, fructose-1,6-bisphosphate, l-asparagine and activation of the decarboxylating activity by succinate. A break in the Arrhenius plot at about 30°C indicates that PEPCK structure is responsive to changes in temperature. The results indicate that pineapple leaves contain two PEPCK forms. The biochemical characterization of the smaller isoform performed in this work suggests that it could participate in both carbon and nitrogen metabolism in vivo by acting as a decarboxylase.
Assuntos
Ananas/enzimologia , Fosfoenolpiruvato Carboxilase/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Descarboxilação , Ácido Oxaloacético/metabolismo , Fosfoenolpiruvato/metabolismo , Fosfoenolpiruvato Carboxilase/química , Fotossíntese/fisiologia , Folhas de Planta/química , Proteínas de Plantas/química , Isoformas de Proteínas , TemperaturaRESUMO
Thermosensors are ubiquitous integral membrane proteins found in all kinds of life. They are involved in many physiological roles, including membrane remodeling, chemotaxis, touch, and pain [1-3], but, the mechanism by which their transmembrane (TM) domains transmit temperature signals is largely unknown. The histidine kinase DesK from Bacillus subtilis is the paradigmatic example of a membrane-bound thermosensor suited to remodel membrane fluidity when the temperature drops below approximately 30°C [1, 4] providing, thus, a tractable system for investigating the mechanism of TM-mediated input-output control of thermal adaptation. Here we show that the multimembrane-spanning domain from DesK can be simplified into a chimerical single-membrane-spanning minimal sensor (MS) that fully retains, in vivo and in vitro, the sensing properties of the parental system. The MS N terminus contains three hydrophilic amino acids near the lipid-water interface creating an instability hot spot. Mutational analysis of this boundary-sensitive beacon revealed that membrane thickness controls the signaling state of the sensor by dictating the hydration level of the metastable hydrophilic spot. Guided by these results we biochemically demonstrated that the MS signal transmission activity is sensitive to bilayer thickness. Membrane thickness could be a general cue for sensing temperature in many organisms.