Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
1.
Artigo em Inglês, Português | LILACS, BDENF - Enfermagem | ID: biblio-1416621

RESUMO

Objetivo: descrever o perfil reprodutivo de mulheres adolescentes participantes de um grupo de gestantes. Método: estudo descritivo, transversal, documental e retrospectivo realizado através da ficha de cadastro de participantes de um grupo de gestante vinculado ao consultório de enfermagem de uma universidade pública federal do rio de janeiro em 2018. Resultados: analisou-se 59 cadastros. houve predominância de mulheres, jovens (71,2%); solteiras (72,3%); multíparas (56%); que tiveram cesárea como via de parto anteriormente (39%); no segundo trimestre de gestação (61%); tipo de pré-natal público (86,4%); desejando a via de parto vaginal (45,8%) e laqueadura pós-parto como método contraceptivo (30,5%), participaram do grupo sem acompanhantes (79,7%) e desejam visita domiciliar pós-parto (78%). Conclusão: identificou-se a necessidade, fatores relacionados e vulnerabilidades em saúde reprodutiva com vistas a implementação de cuidados primários voltados à promoção da saúde, prevenção de agravos e detecção precoce.


Objective: to describe the reproductive profile of adolescent women participating in a group of pregnant women. Method:descriptive, cross-sectional, documentary and retrospective study carried out through the registration form of participants of a group of pregnant women linked to the nursing office of a federal public university in Rio de Janeiro in 2018. Results: 59 records were analyzed. there was a predominance of women, young people (71.2%); single (72.3%); multiparous (56%); who had previously had a cesarean section (39%); in the second trimester of pregnancy (61%); type of public prenatal care (86.4%); desiring vaginal delivery (45.8%) and postpartum tubal ligation as a contraceptive method (30.5%), participated in the group without companions (79.7%) and desired postpartum home visit (78%). Conclusion: the need, related factors and vulnerabilities in reproductive health were identified with a view to implementing primary care aimed at health promotion, disease prevention and early detection.


Objetivo: describir el perfil reproductivo de mujeres adolescentes participantes de un grupo de gestantes. Método: estudio descriptivo, transversal, documental y retrospectivo realizado a través del formulario de registro de participantes de un grupo de gestantes vinculadas al consultorio de enfermería de una universidad pública federal de Río de Janeiro en 2018. Resultados: se analizaron 59 registros. hubo predominio de mujeres, jóvenes (71,2%); soltero (72,3%); multíparas (56%); que previamente había tenido una cesárea (39%); en el segundo trimestre del embarazo (61%); tipo de atención prenatal pública (86,4%); deseando parto vaginal (45,8%) y ligadura de trompas posparto como método anticonceptivo (30,5%), participaron del grupo sin acompañantes (79,7%) y desearon visita domiciliaria posparto (78%). Conclusión: se identificaron la necesidad, los factores relacionados y las vulnerabilidades en salud reproductiva para la implementación de la atención primaria dirigida a la promoción de la salud, la prevención de enfermedades y la detección temprana.


Assuntos
Humanos , Feminino , Gravidez , Adolescente , Adulto Jovem , Gravidez na Adolescência/estatística & dados numéricos , Estudos Retrospectivos , Saúde Reprodutiva/estatística & dados numéricos , Gravidez na Adolescência/prevenção & controle , Cuidado Pré-Natal/estatística & dados numéricos , Educação em Saúde
2.
Biochem J ; 479(22): 2365-2377, 2022 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-36373632

RESUMO

Phytoene synthase (PSY) converts two molecules of geranyl-geranyl diphosphate to phytoene, the key regulatory step in carotenogenesis. However, post-translational mechanisms that control PSY expression are scarcely understood. Carotenoid biosynthesis (mainly bacterioruberin) is a distinctive feature of haloarchaea thriving in hypersaline environments. Carotenogenesis is negatively regulated by the AAA+ LonB protease in the haloarchaeon Haloferax volcanii as it controls PSY degradation. We investigated the relevance of the C-terminal portion of HvPSY as a regulatory element for carotenoid biosynthesis. H. volcanii mutants were constructed to express full-length HvPSY protein (strain HVPSYwt) and truncated HvPSY lacking 10 (HVPSY10), 20 (HVPSY20) or 34 amino acids (HVPSY34) at the C-terminus. Cells of HVPSY20 and HVPSY34 showed hyperpigmentation (bacterioruberin content 3-fold higher than HVPSYwt) which correlated with increased PSY protein abundance (2-fold in HVPSY34) while they contained less psy transcript level compared with HVPSYwt. In vivo degradation assays showed that HvPSY34 was more stable than HvPSYwt. Collectively, these results show that the C-terminal region of HvPSY contains a 'recognition determinant' for proteolysis in H. volcanii. Preliminary evidence suggests that LonB is involved in the recognition mechanism. This study provides the first identification of a regulatory sequence in an archaeal PSY for the post-translational control of carotenogenesis.


Assuntos
Haloferax volcanii , Haloferax volcanii/genética , Haloferax volcanii/metabolismo , Glicogênio Sintase , Carotenoides/química
3.
Methods Mol Biol ; 2522: 301-317, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36125758

RESUMO

Coimmunoprecipitation is a powerful and commonly used method to identify protein-protein interactions in a physiological context. Here, we report a coimmunoprecipitation protocol that was adapted and optimized for the haloarchaeon Haloferax volcanii to identify interacting partners to the LonB protease. This protocol includes the in vivo cross-linking of H. volcanii proteins using two different crosslinker agents, dithiobis(succinimidyl propionate) and formaldehyde, followed by immunoprecipitation with anti-LonB antibody conjugated to Protein A - Sepharose beads. Tryptic on-bead protein digestion was performed combined with Mass Spectrometry analysis of peptides for the identification and quantification of LonB ligands.


Assuntos
Haloferax volcanii , Formaldeído , Imunoprecipitação , Peptídeo Hidrolases/metabolismo , Peptídeos/análise , Propionatos , Proteínas , Sefarose
4.
Methods Mol Biol ; 2522: 331-343, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36125760

RESUMO

Carotenoids are bioactive molecules known to promote human health. Many extreme halophilic archaea synthesize carotenoids, mainly represented by C50 bacterioruberin (BR) and its derivatives. BR has a potent antioxidant capacity, even higher than that of ß-carotene, thus, there is an increasing interest to advance the study of its biological properties as well as to extend its current applications. Here, we describe a procedure to extract and characterize carotenoids (enriched in BR) from haloarchaea using a "hyperpigmented" genetically modified strain of Haloferax volcanii.


Assuntos
Antioxidantes , Haloferax volcanii , Carotenoides , Humanos , beta Caroteno
5.
Methods Mol Biol ; 2522: 319-330, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36125759

RESUMO

Extreme halophilic archaea (haloarchaea) have adapted their physiology and biomolecules to thrive in saline environments (>2 M NaCl). Many haloarchaea produce extracellular hydrolases (including proteases) with potential biotechnological applications, which require unusual high salt concentrations to attain their function and maintain their stability. These conditions restrict many of the standard methods used to study these enzymes such as activity determination and/or protein purification. Here, we describe basic protocols to detect and measure extracellular proteolytic activity in haloarchaea including casein hydrolysis on agar plates, quantitative proteolytic activity determination by the azocasein assay and gelatin zymography in presence of the compatible solute glycine-betaine.


Assuntos
Caseínas , Cloreto de Sódio , Ágar , Betaína , Gelatina , Glicina , Peptídeo Hidrolases/metabolismo
6.
7.
Front Microbiol ; 13: 940865, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35814708

RESUMO

Proteolysis plays a fundamental role in many processes that occur within the cellular membrane including protein quality control, protein export, cell signaling, biogenesis of the cell envelope among others. Archaea are a distinct and physiologically diverse group of prokaryotes found in all kinds of habitats, from the human and plant microbiomes to those with extreme salt concentration, pH and/or temperatures. Thus, these organisms provide an excellent opportunity to extend our current understanding on the biological functions that proteases exert in cell physiology including the adaptation to hostile environments. This revision describes the advances that were made on archaeal membrane proteases with regard to their biological function and potential natural targets focusing on the model haloarchaeon Haloferax volcanii.

8.
Saúde Soc ; 31(2): e220055pt, 2022.
Artigo em Português | LILACS | ID: biblio-1390327

RESUMO

Resumo Parte significativa da literatura sobre a gênese das instituições brasileiras voltadas à regulamentação ética de práticas de pesquisa científica envolvendo seres humanos costuma remontar a eventos internacionais, a exemplo dos ocorridos durante e após a Segunda Guerra Mundial, como disparadores de uma consciência ética global da qual o Brasil teria tomado parte. A partir de revisão de literatura e recurso de abordagem genealógica, investiga-se como certos eventos ocorridos no nosso país, como a atuação de movimentos sociais frente aos ensaios clínicos com Norplant, nos anos 1980, e com antirretrovirais (ARV), nos anos 1990, são fundamentais para a compreensão de distintos momentos de institucionalização da ética em pesquisa no Brasil e suas respectivas orientações políticas. Com base na reconstrução desses episódios, argumenta-se que os conteúdos particulares das agendas públicas sobre as práticas científicas biomédicas se ancoraram em contextos específicos de contestação, cujas demandas políticas foram agenciadas em termos notadamente éticos. A configuração histórica da ética em pesquisa no Brasil conjuga sujeitos, fatores e lutas políticas que lhe conferem um caráter dinâmico, cuja compreensão demanda levar em conta a atuação de movimentos sociais com relação à regulamentação dos ensaios clínicos.


Abstract A significant part of the literature on the genesis of the Brazilian institutions devoted to the ethical regulation of scientific research involving human beings usually recalls international events, such as those that occurred during and after the II World War, as triggers of a global ethical conscience of which Brazil would have taken part. Based on review of literature, and a genealogical approach, this assay investigates how certain events that occurred in Brazil, such as the actions of social movements in face of clinical trials with Norplant in the 1980s and with antiretrovirals in the 1990s, are fundamental for understanding the different moments of institutionalization of research ethics in Brazil, and its political orientations. Based on the reconstruction of these episodes, it is argued that particular contents of public agendas on biomedical scientific practices were anchored in specific contexts of contestation led by social movements, whose political demands were described in notably ethical terms. The historical configuration of research ethics in Brazil gathers subjects, factors, and political struggles that provide it with a dynamic character. Understanding this context demands considering the actions of social movements aimed at the regulation of clinical trials.


Assuntos
Brasil , Tecnologia Biomédica , Ética em Pesquisa , Ciência, Tecnologia e Sociedade , Ativismo Político
10.
Nat Commun ; 11(1): 3145, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32561711

RESUMO

While many aspects of archaeal cell biology remain relatively unexplored, systems biology approaches like mass spectrometry (MS) based proteomics offer an opportunity for rapid advances. Unfortunately, the enormous amount of MS data generated often remains incompletely analyzed due to a lack of sophisticated bioinformatic tools and field-specific biological expertise for data interpretation. Here we present the initiation of the Archaeal Proteome Project (ArcPP), a community-based effort to comprehensively analyze archaeal proteomes. Starting with the model archaeon Haloferax volcanii, we reanalyze MS datasets from various strains and culture conditions. Optimized peptide spectrum matching, with strict control of false discovery rates, facilitates identifying > 72% of the reference proteome, with a median protein sequence coverage of 51%. These analyses, together with expert knowledge in diverse aspects of cell biology, provide meaningful insights into processes such as N-terminal protein maturation, N-glycosylation, and metabolism. Altogether, ArcPP serves as an invaluable blueprint for comprehensive prokaryotic proteomics.


Assuntos
Proteínas Arqueais/metabolismo , Haloferax volcanii/fisiologia , Proteoma/metabolismo , Proteômica/métodos , Sequência de Aminoácidos , Conjuntos de Dados como Assunto , Glicosilação , Espectrometria de Massas
12.
Proteomics ; 18(14): e1800116, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29888524

RESUMO

The dynamic changes that take place along the phases of microbial growth (lag, exponential, stationary, and death) have been widely studied in bacteria at the molecular and cellular levels, but little is known for archaea. In this study, a high-throughput approach was used to analyze and compare the proteomes of two haloarchaea during exponential and stationary growth: the neutrophilic Haloferax volcanii and the alkaliphilic Natrialba magadii. Almost 2000 proteins were identified in each species (≈50% of the predicted proteome). Among them, 532 and 432 were found to be differential between growth phases in H. volcanii and N. magadii, respectively. Changes upon entrance into stationary phase included an overall increase in proteins involved in the transport of small molecules and ions, stress response, and fatty acid catabolism. Proteins related to genetic processes and cell division showed a notorious decrease in amount. The data reported in this study not only contributes to our understanding of the exponential-stationary growth phase transition in extremophilic archaea but also provides the first comprehensive analysis of the proteome composition of N. magadii. The MS proteomics data have been deposited in the ProteomeXchange Consortium with the dataset identifier JPST000395.


Assuntos
Proteínas Arqueais/metabolismo , Halobacteriaceae/crescimento & desenvolvimento , Halobacteriaceae/metabolismo , Haloferax volcanii/crescimento & desenvolvimento , Haloferax volcanii/metabolismo , Espectrometria de Massas/métodos , Proteoma/análise
13.
Int J Biol Macromol ; 113: 1134-1141, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29524492

RESUMO

Nep (Natrialba magadii extracellular protease) is a halolysin-like peptidase secreted by the haloalkaliphilic archaeon Natrialba magadii. Many extracellular proteases have been characterized from archaea to bacteria as adapted to hypersaline environments retaining function and stability until 4.0M NaCl. As observed in other secreted halolysins, this stability can be related to the presence of a C-terminal extension (CTE) sequence. In the present work, we compared the biochemical properties of recombinant Nep protease with the truncated form at the 134 amino acids CTE (Nep∆CTE), that was more active in 4M NaCl than the non-truncated wild type enzyme. Comparable to the wild type, Nep∆CTE protease is irreversibly inactivated at low salt solutions. The substrate specificity of the truncated Nep∆CTE was similar to that of wild type form as demonstrated by a combinatorial library of FRET substrates. The enzyme stability, the effect of different salts and the thermodynamics assays using different lengths of substrates demonstrated similarities between the two forms. Altogether, these data provide further information on the stability and structural determinants of halolysins under different salinities, especially concerning the enzymatic behavior.


Assuntos
Espaço Extracelular/enzimologia , Halobacteriaceae/citologia , Peptídeo Hidrolases/química , Peptídeo Hidrolases/metabolismo , Sais/farmacologia , Relação Dose-Resposta a Droga , Halobacteriaceae/enzimologia , Cinética , Solventes/química , Relação Estrutura-Atividade , Especificidade por Substrato
14.
Interface (Botucatu, Online) ; 22(64): 97-108, jan.-mar. 2018. ilus
Artigo em Português | LILACS | ID: biblio-893465

RESUMO

O objetivo foi descrever e analisar modelos e estratégias internacionais de envolvimento de usuários de sistemas de saúde nos processos de avaliação para incorporação de tecnologias de saúde registrados na literatura científica. Realizou-se levantamento da literatura em sete bases científicas, seleção de artigos, identificação e descrição dos modelos adotados em diferentes países. De 392 artigos identificados, oito foram selecionados segundo critérios de elegibilidade. As estratégias e modelos identificados foram classificados segundo o domínio do envolvimento; tipo de público e nível de envolvimento. A descrição dos modelos permitiu identificar uma ampla diversidade de experiências para envolvimento do público em processos de ATS. Os resultados apontam para a troca de conhecimentos e informações como forma de reduzir o distanciamento entre os usuários e os processos de avaliação mediante estratégias diversificadas de incentivo à participação.(AU)


This paper aims to describe and analyze international models and strategies for the involvement of patients of healthcare systems in HTA processes. A literature review was conducted on papers from seven databases, followed by selection of papers, identification and description of the models adopted in different countries. Based on the 392 articles identified, eight were selected for analysis based on eligibility criteria. The models and strategies were classified according to the domains of the involvement; type of audiences and level of involvement. The description of the models allowed identifying a wide range of experiences for citizens' involvement in the HTA processes. The results point to knowledge and information exchange as ways to reduce the distance between patients and HTA processes through diversified strategies to foster participation.(AU)


El objetivo fue describir y analizar modelos y estrategias internacionales de envolvimiento de usuarios de sistemas de salud en los procesos de evaluación para incorporación de tecnologías de salud registrados en la literatura científica. Se realizó un levantamiento de la literatura en siete bases científicas, selección de artículos, identificación y descripción de los modelos adoptados en diferentes países. De 392 artículos identificados, se seleccionaron ocho según criterios de elegibilidad. Las estrategias y modelos identificados se clasificaron según el dominio del envolvimiento, tipo de público y nivel de envolvimiento. La descripción de los modelos permitió identificar una amplia diversidad de experiencias para envolvimiento del público en procesos de ETS. Los resultados señalan el intercambio de conocimientos e informaciones como forma de reducir el distanciamiento entre los usuarios y los procesos de evaluación mediante estrategias diversificadas de incentivo a la participación.(AU)


Assuntos
Humanos , Tecnologia Biomédica/métodos , Sistemas de Saúde , Participação do Paciente
15.
J Proteome Res ; 17(3): 1158-1171, 2018 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-29411617

RESUMO

The membrane protease LonB is an essential protein in the archaeon Haloferax volcanii and globally impacts its physiology. However, natural substrates of the archaeal Lon protease have not been identified. The whole proteome turnover was examined in a H. volcanii LonB mutant under reduced and physiological protease levels. LC-MS/MS combined with stable isotope labeling was applied for the identification/quantitation of membrane and cytoplasm proteins. Differential synthesis and degradation rates were evidenced for 414 proteins in response to Lon expression. A total of 58 proteins involved in diverse cellular processes showed a degradation pattern (none/very little degradation in the absence of Lon and increased degradation in the presence of Lon) consistent with a LonB substrate, which was further substantiated for several of these candidates by pull-down assays. The most notable was phytoene synthase (PSY), the rate-limiting enzyme in carotenoid biosynthesis. The rapid degradation of PSY upon LonB induction in addition to the remarkable stabilization of this protein and hyperpigmentation phenotype in the Lon mutant strongly suggest that PSY is a LonB substrate. This work identifies for the first time candidate targets of the archaeal Lon protease and establishes proteolysis by Lon as a novel post-translational regulatory mechanism of carotenogenesis.


Assuntos
Proteínas Arqueais/metabolismo , Carotenoides/biossíntese , Regulação da Expressão Gênica em Archaea , Geranil-Geranildifosfato Geranil-Geraniltransferase/metabolismo , Haloferax volcanii/enzimologia , Protease La/metabolismo , Proteoma/metabolismo , Proteínas Arqueais/genética , Cromatografia Líquida , Ontologia Genética , Geranil-Geranildifosfato Geranil-Geraniltransferase/genética , Haloferax volcanii/genética , Marcação por Isótopo/métodos , Anotação de Sequência Molecular , Mutação , Protease La/genética , Biossíntese de Proteínas , Proteólise , Proteoma/genética , Especificidade por Substrato , Espectrometria de Massas em Tandem
16.
J Proteome Res ; 17(3): 961-977, 2018 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-29301397

RESUMO

Rhomboids are conserved intramembrane serine proteases involved in cell signaling processes. Their role in prokaryotes is scarcely known and remains to be investigated in Archaea. We previously constructed a rhomboid homologue deletion mutant (ΔrhoII) in Haloferax volcanii, which showed reduced motility, increased novobiocin sensitivity, and an N- glycosylation defect. To address the impact of rhoII deletion on H. volcanii physiology, the proteomes of mutant and parental strains were compared by shotgun proteomics. A total of 1847 proteins were identified (45.8% of H. volcanii predicted proteome), from which 103 differed in amount. Additionally, the mutant strain evidenced 99 proteins with altered electrophoretic migration, which suggested differential post-translational processing/modification. Integral membrane proteins that evidenced variations in concentration, electrophoretic migration, or semitryptic cleavage in the mutant were considered as potential RhoII targets. These included a PrsW protease homologue (which was less stable in the mutant strain), a predicted halocyanin, and six integral membrane proteins potentially related to the mutant glycosylation (S-layer glycoprotein, Agl15) and cell adhesion/motility (flagellin1, HVO_1153, PilA1, and PibD) defects. This study investigated for the first time the impact of a rhomboid protease on the whole proteome of an organism.


Assuntos
Proteínas Arqueais/genética , Deleção de Genes , Regulação da Expressão Gênica em Archaea , Haloferax volcanii/genética , Processamento de Proteína Pós-Traducional , Proteoma/genética , Proteínas Arqueais/classificação , Proteínas Arqueais/isolamento & purificação , Proteínas Arqueais/metabolismo , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Adesão Celular , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Endopeptidases/deficiência , Endopeptidases/genética , Ontologia Genética , Glicosilação , Haloferax volcanii/química , Haloferax volcanii/metabolismo , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Metaloproteínas/genética , Metaloproteínas/metabolismo , Anotação de Sequência Molecular , Proteoma/classificação , Proteoma/isolamento & purificação , Proteoma/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Especificidade por Substrato
17.
Extremophiles ; 19(6): 1133-43, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26369649

RESUMO

The biodiversity and biotechnological potential of microbes from central Argentinean halophilic environments have been poorly explored. Salitral Negro and Colorada Grande salterns are neutral hypersaline basins exploded for NaCl extraction. As part of an ecological analysis of these environments, two bacterial and seven archaeal representatives were isolated, identified and examined for their biotechnological potential. The presence of hydrolases (proteases, amylases, lipases, cellulases and nucleases) and bioactive molecules (surfactants and antimicrobial compounds) was screened. While all the isolates exhibited at least one of the tested activities or biocompounds, the species belonging to Haloarcula genus were the most active, also producing antimicrobial compounds against their counterparts. In general, the biosurfactants were more effective against olive oil and aromatic compounds than detergents (SDS or Triton X-100). Our results demonstrate the broad spectrum of activities with biotechnological potential exhibited by the microorganisms inhabiting the Argentinean salterns and reinforce the importance of screening pristine extreme environments to discover interesting/novel bioactive molecules.


Assuntos
Haloarcula/metabolismo , Microbiologia Industrial/métodos , Tensoativos/metabolismo , Anti-Infecciosos/metabolismo , Proteínas Arqueais/metabolismo , Haloarcula/enzimologia , Haloarcula/genética , Haloarcula/isolamento & purificação , Hidrolases/metabolismo , Tolerância ao Sal
18.
Data Brief ; 4: 50-3, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26217762

RESUMO

This data article provides information in support of the research article "Global role of the membrane protease LonB in Archaea: Potential protease targets revealed by quantitative proteome analysis of a lonB mutant in Haloferax volcanii" [1]. The proteome composition of a wt and a LonB protease mutant strain (suboptimal expression) in the archaeon Haloferax volcanii was assessed by a quantitative shotgun proteomic approach. Membrane and cytosol fractions of H. volcanii strains were examined at two different growth stages (exponential and stationary phase). Data is supplied in the present article. This study represents the first proteome examination of a Lon-deficient cell of the Archaea Domain.

19.
J Proteomics ; 121: 1-14, 2015 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-25829260

RESUMO

The membrane-associated LonB protease is essential for viability in Haloferax volcanii, however, the cellular processes affected by this protease in archaea are unknown. In this study, the impact of a lon conditional mutation (down-regulation) on H. volcanii physiology was examined by comparing proteomes of parental and mutant cells using shotgun proteomics. A total of 1778 proteins were identified (44% of H. volcanii predicted proteome) and 142 changed significantly in amount (≥2 fold). Of these, 66 were augmented in response to Lon deficiency suggesting they could be Lon substrates. The "Lon subproteome" included soluble and predicted membrane proteins expected to participate in diverse cellular processes. The dramatic stabilization of phytoene synthase (57 fold) in concert with overpigmentation of lon mutant cells suggests that Lon controls carotenogenesis in H. volcanii. Several hypothetical proteins, which may reveal novel functions and/or be involved in adaptation to extreme environments, were notably increased (300 fold). This study, which represents the first proteome examination of a Lon deficient archaeal cell, shows that Lon has a strong impact on H. volcanii physiology evidencing the cellular processes controlled by this protease in Archaea. Additionally, this work provides a platform for the discovery of novel targets of Lon proteases. BIOLOGICAL SIGNIFICANCE: The proteome of a Lon-deficient archaeal cell was examined for the first time showing that Lon has a strong impact on H. volcanii physiology and evidencing the proteins and cellular processes controlled by this protease in Archaea. This work will facilitate future investigations aiming to address Lon function in archaea and provides a platform for the discovery of endogenous targets of the archaeal-type Lon as well as novel targets/processes regulated by Lon proteases. This knowledge will advance the understanding on archaeal physiology and the biological function of membrane proteases in microorganisms.


Assuntos
Proteínas Arqueais/metabolismo , Haloferax volcanii/enzimologia , Proteínas de Membrana/metabolismo , Peptídeo Hidrolases/metabolismo , Proteoma/metabolismo , Aminoácidos/química , Carotenoides/química , Membrana Celular/metabolismo , Citoplasma/metabolismo , Eletroforese em Gel de Poliacrilamida , Metabolismo dos Lipídeos , Mutação , Proteômica , Espectrometria de Massas por Ionização por Electrospray
20.
Front Microbiol ; 6: 39, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25774151

RESUMO

The function of membrane proteases range from general house-keeping to regulation of cellular processes. Although the biological role of these enzymes in archaea is poorly understood, some of them are implicated in the biogenesis of the archaeal cell envelope and surface structures. The membrane-bound ATP-dependent Lon protease is essential for cell viability and affects membrane carotenoid content in Haloferax volcanii. At least two different proteases are needed in this archaeon to accomplish the posttranslational modifications of the S-layer glycoprotein. The rhomboid protease RhoII is involved in the N-glycosylation of the S-layer protein with a sulfoquinovose-containing oligosaccharide while archaeosortase ArtA mediates the proteolytic processing coupled-lipid modification of this glycoprotein facilitating its attachment to the archaeal cell surface. Interestingly, two different signal peptidase I homologs exist in H. volcanii, Sec11a and Sec11b, which likely play distinct physiological roles. Type IV prepilin peptidase PibD processes flagellin/pilin precursors, being essential for the biogenesis and function of the archaellum and other cell surface structures in H. volcanii.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...