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1.
Braz J Biol ; 82: e265235, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36417624

RESUMO

The biotechnological potential of microalgae has been the target of a range of research aimed at using its potential to produce macromolecules with high added value. Particular focus has been given to biofuels' production, such as biohydrogen, biodiesel, and bioethanol from lipids and carbohydrates extracted from microalgal biomass. Bioprospecting and accurate identification of microalgae from the environment are important in the search for strains with better performance. Methodologies that combine morphology and molecular techniques allow more precise knowledge of species. Thereby, this work aimed to identify the new strain LGMM0013 collected at Iraí Reservoir, located in Paraná state, Brazil, and to evaluate the production of biomass, carbohydrates, and lipids from this new microalgal strain. Based on morphology and phylogenetic tree from internal transcribed spacer (ITS), strain LGMM0013 was identified as Desmodesmus abundans. D. abundans accumulated 1500 mg L-1 of dried biomass after 22 days of cultivation in autotrophic conditions, 50% higher than Tetradesmus obliquus (LGMM0001) (Scenedesmaceae-Chlorophyceae), usually grown in photobioreactors located at NPDEAS at the Federal University of Paraná (UFPR) to produce biomass. Analysis of the D. abundans biomass from showed an accumulation of 673.39 mg L-1 of carbohydrates, 130% higher than T. obliquus (LGMM0001). Lipid production was 259.7 mg L-1, equivalent to that of T. obliquus. Nitrogen deprivation increased the production of biomass and carbohydrates in D. abundans LGMM0013, indicating this new strain greater biomass production capacity.


Assuntos
Clorofíceas , Microalgas , Biomassa , Filogenia , Brasil , Microalgas/genética , Biocombustíveis , Carboidratos , Lipídeos
2.
Plant Mol Biol ; 90(6): 561-74, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26821805

RESUMO

A wide range of rhizosphere diazotrophic bacteria are able to establish beneficial associations with plants, being able to associate to root surfaces or even endophytically colonize plant tissues. In common, both associative and endophytic types of colonization can result in beneficial outcomes to the plant leading to plant growth promotion, as well as increase in tolerance against biotic and abiotic stresses. An intriguing question in such associations is how plant cell surface perceives signals from other living organisms, thus sorting pathogens from beneficial ones, to transduce this information and activate proper responses that will finally culminate in plant adaptations to optimize their growth rates. This review focuses on the recent advances in the understanding of genetic and epigenetic controls of plant-bacteria signaling and recognition during beneficial associations with associative and endophytic diazotrophic bacteria. Finally, we propose that "soil-rhizosphere-rhizoplane-endophytes-plant" could be considered as a single coordinated unit with dynamic components that integrate the plant with the environment to generate adaptive responses in plants to improve growth. The homeostasis of the whole system should recruit different levels of regulation, and recognition between the parties in a given environment might be one of the crucial factors coordinating these adaptive plant responses.


Assuntos
Fenômenos Fisiológicos Bacterianos/genética , Endófitos/fisiologia , Epigênese Genética , Fixação de Nitrogênio/fisiologia , Plantas/microbiologia , Epigênese Genética/fisiologia , Fixação de Nitrogênio/genética , Plantas/genética , Rizosfera
3.
New Microbes New Infect ; 7: 94-6, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26442151

RESUMO

We describe what is to our knowledge the first fatal case of central nervous system Enterovirus infection in Brazil. Molecular and phylogenetic characterization revealed that Enterovirus A was the aetiologic agent of this case.

4.
J Exp Bot ; 65(19): 5631-42, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25114015

RESUMO

Some beneficial plant-interacting bacteria can biologically fix N2 to plant-available ammonium. Biological nitrogen fixation (BNF) is an important source of nitrogen (N) input in agriculture and represents a promising substitute for chemical N fertilizers. Diazotrophic bacteria have the ability to develop different types of root associations with different plant species. Among the highest rates of BNF are those measured in legumes nodulated by endosymbionts, an already very well documented model of plant-diazotrophic bacterial association. However, it has also been shown that economically important crops, especially monocots, can obtain a substantial part of their N needs from BNF by interacting with associative and endophytic diazotrophic bacteria, that either live near the root surface or endophytically colonize intercellular spaces and vascular tissues of host plants. One of the best reported outcomes of this association is the promotion of plant growth by direct and indirect mechanisms. Besides fixing N, these bacteria can also produce plant growth hormones, and some species are reported to improve nutrient uptake and increase plant tolerance against biotic and abiotic stresses. Thus, this particular type of plant-bacteria association consists of a natural beneficial system to be explored; however, the regulatory mechanisms involved are still not clear. Plant N status might act as a key signal, regulating and integrating various metabolic processes that occur during association with diazotrophic bacteria. This review will focus on the recent progress in understanding plant association with associative and endophytic diazotrophic bacteria, particularly on the knowledge of the N networks involved in BNF and in the promotion of plant growth.


Assuntos
Bactérias/metabolismo , Fixação de Nitrogênio , Nitrogênio/metabolismo , Plantas/microbiologia , Produtos Agrícolas , Endófitos , Modelos Biológicos , Nodulação , Raízes de Plantas/microbiologia , Transdução de Sinais , Simbiose
5.
Arch Virol ; 159(5): 1155-7, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24197788

RESUMO

In October 2009, our laboratory was contacted by a Brazilian Public Health organization regarding a severe community outbreak of an acute exanthematic and febrile disease in the Brazilian Amazon that primarily affected children. A total of 44 patients with febrile disease were identified by the local public health system, 37 of whom were children between 1 and 9 years of age. Molecular virological and phylogenetic characterization revealed that enterovirus B was the etiological agent of this outbreak, which was characterized by a clinical presentation known as herpangina.


Assuntos
Surtos de Doenças , Enterovirus Humano B/isolamento & purificação , Infecções por Enterovirus/virologia , Herpangina/virologia , Adulto , Brasil , Criança , Pré-Escolar , Enterovirus Humano B/genética , Infecções por Enterovirus/epidemiologia , Infecções por Enterovirus/patologia , Herpangina/epidemiologia , Herpangina/patologia , Humanos , Lactente , Filogenia
6.
Vet Rec ; 171(19): 476, 2012 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-23065256

RESUMO

Orf virus (ORFV), the prototype of the genus Parapoxvirus, is the aetiological agent of contagious ecthyma (CE), a pustular dermatitis that afflicts domestic and wild small ruminants. CE is one of the most widespread poxvirus diseases in the world, causing public health impacts. Outbreaks of ORFV have been observed in all geographical regions of Brazil, affecting ovine and caprine herds. The origins, epidemiology and identity of Brazilian ORFVs are unknown, and no comparative or phylogenetic studies of these viruses have been performed. In the present study, we revisited CE outbreaks which occurred until 32 years ago, and we assessed, genetically, five viral isolates. We performed the sequencing and analysis of the three ORFV molecular markers: B2L gene, virus interferon resistance gene (VIR) and the vascular endothelial growth factor gene. Nucleotide and amino acid analysis of the analysed genes demonstrated that Brazilian ORFVs do not form a unique cluster, and presented more similarity to other worldwide ORFV samples than with each other. These data raise the questions of whether there are different worldwide ORFVs circulating in Brazil, or if all the Brazilian ORFV samples are of the same virus taken at distinct time points.


Assuntos
Surtos de Doenças/veterinária , Ectima Contagioso/virologia , Doenças das Cabras/virologia , Vírus do Orf/genética , Animais , Brasil/epidemiologia , Ectima Contagioso/epidemiologia , Marcadores Genéticos/genética , Doenças das Cabras/epidemiologia , Cabras , Vírus do Orf/isolamento & purificação , Estudos Retrospectivos , Ovinos
7.
Colorectal Dis ; 14(11): 1372-9, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22390340

RESUMO

AIM: There is poor consensus in the literature about measuring perineal descent. We aimed to assess symptoms and quality of life in constipated patients with abnormal perineal descent. METHOD: Constipated patients were categorized into those with obstructed defaecation, colonic inertia, mixed disorders and irritable bowel syndrome constipation types. Anal physiology was performed. KESS score, Irritable Bowel Syndrome Quality of Life and SF-12 questionnaires were completed. The position of the perineum was measured by defaecography. Patients were divided into two groups according to the position of the perineal descent at rest: group 1 (normal < 3.5 cm) and group 2 (abnormal > 3.5 cm). RESULTS: Fifty-eight patients were identified, 23 (40%) in group 1 and 35 (60%) in group 2. Patients in group 2 were older (P = 0.007), had a higher body mass index (BMI; P = 0.003), a higher rate of hysterectomy (P = 0.04) and more vaginal deliveries (P = 0.001). Obstructed defaecation was the predominant subtype of constipation. Group 1 had more difficulty in initiating defaecation and group 2 presented more cases with intussusception and enterocele (P = 0.03 for both). Group 2 had a lesser degree of perineal descent between rest and straining. Rectal compliance was greater in group 2 (P = 0.03). Symptoms and quality of life scores were similar between the groups. CONCLUSION: Radiologically determined excessive perineal descent is not indicative of worse symptoms or quality of life. This radiological finding does not warrant further investigation.


Assuntos
Canal Anal/fisiopatologia , Constipação Intestinal/classificação , Defecação/fisiologia , Períneo/fisiopatologia , Adulto , Idoso , Canal Anal/anatomia & histologia , Canal Anal/diagnóstico por imagem , Constipação Intestinal/etiologia , Constipação Intestinal/fisiopatologia , Defecografia , Feminino , Humanos , Síndrome do Intestino Irritável/complicações , Masculino , Pessoa de Meia-Idade , Períneo/anatomia & histologia , Períneo/diagnóstico por imagem , Estudos Prospectivos , Qualidade de Vida , Índice de Gravidade de Doença , Inquéritos e Questionários
8.
Clin Vaccine Immunol ; 18(11): 1823-33, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21900533

RESUMO

Enteropathogenic Escherichia coli (EPEC) is a common cause of diarrhea in children from developing countries. Intimate adhesion of the bacteria to intestinal cells occurs via binding of the adhesin intimin to the TIR receptor exposed on cell surfaces. Here, Lactobacillus casei expressing a fragment of ß-intimin (L. casei-Int(cv)) was tested as mucosal vaccines in mice against intestinal colonization with the murine pathogen Citrobacter rodentium. Oral or sublingual immunization of C57BL/6 mice with L. casei-Int(cv) induced anti-Int(cv) IgA in feces but no IgG in sera. Conversely, anti-Int(cv) IgG was induced in the sera of mice after sublingual immunization with purified Int(cv). All vaccines were able to decrease C. rodentium recovery from feces. However, this reduction was more evident and sustained over time in mice immunized with L. casei-Int(cv) by the sublingual route. These mice also displayed an increase in interleukin 6 (IL-6) and gamma interferon (IFN-γ) secretion by spleen cells 10 days after infection. Additionally, oral or sublingual immunization of C3H/HePas mice, which are highly susceptible to C. rodentium infection, with L. casei-Int(cv) induced anti-Int(cv) antibodies and significantly increased survival after challenge. Immunohistological analysis of colon sections revealed that C. rodentium was located in deep fractions of the tissue from C3H/HePas mice immunized with L. casei whereas superficial staining was observed in colon sections from mice immunized with L. casei-Int(cv.) The results indicate that vaccines composed of L. casei expressing intimin may represent a promising approach and that the C3H/HePas infection model with C. rodentium can be used to evaluate potential vaccines against EPEC.


Assuntos
Adesinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Citrobacter rodentium/imunologia , Portadores de Fármacos , Infecções por Enterobacteriaceae/prevenção & controle , Proteínas de Escherichia coli/imunologia , Vetores Genéticos , Lacticaseibacillus casei/genética , Adesinas Bacterianas/genética , Administração Oral , Administração Sublingual , Animais , Anticorpos Antibacterianos/sangue , Vacinas Bacterianas/administração & dosagem , Citrobacter rodentium/genética , Colo/patologia , Infecções por Enterobacteriaceae/imunologia , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/mortalidade , Proteínas de Escherichia coli/genética , Fezes/microbiologia , Feminino , Humanos , Imunização/métodos , Interferon gama/metabolismo , Interleucina-6/metabolismo , Leucócitos Mononucleares/imunologia , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Baço/imunologia , Análise de Sobrevida , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia
9.
Arch Virol ; 155(7): 1139-44, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20428903

RESUMO

Vaccinia virus strains from the family Poxviridae have been frequently isolated in Brazil and associated with outbreaks of exanthematic disease affecting cows and humans. An ELISA IgG was applied to evaluate the seroprevalence of orthopoxviruses in a community located in a rural settlement in the Amazon region, where no orthopoxvirus outbreaks have yet been reported. An overall seroprevalence of 27.89% was found, and it was 23.38% in the non-vaccinated population (smallpox vaccination). These results strongly suggest that orthopoxviruses circulate in this population, and it is the first finding of seropositivity for orthopoxviruses in a population without any previously reported outbreaks.


Assuntos
Imunoglobulina G/sangue , Orthopoxvirus/imunologia , Infecções por Poxviridae/epidemiologia , Adolescente , Adulto , Idoso , Anticorpos Antivirais/sangue , Brasil/epidemiologia , Criança , Pré-Escolar , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Razão de Chances , Infecções por Poxviridae/imunologia , Infecções por Poxviridae/virologia , Fatores de Risco , População Rural , Estudos Soroepidemiológicos , Adulto Jovem
10.
Braz. j. phys. ther. (Impr.) ; 11(2): 169-175, mar.-abr. 2007. tab, ilus
Artigo em Português | LILACS | ID: lil-458023

RESUMO

INTRODUÇÃO: O comprimento muscular pode ser inferido através da determinação da relação comprimento-tensão do músculo. Essa relação é tradicionalmente investigada por meio da medida do torque máximo produzido pelo músculo e do ângulo em que esse torque é gerado. OBJETIVO: O presente estudo verificou a confiabilidade teste-reteste de um método de mensuração do ângulo de pico de torque ativo dos isquiossurais em jovens saudáveis. MÉTODO: Vinte e cinco indivíduos saudáveis (22,88 ± 1,67 anos) foram avaliados duas vezes em um intervalo de três semanas. Um dinamômetro isocinético foi utilizado no modo passivo para avaliar o torque passivo dos isquiossurais. A atividade muscular foi monitorada para garantir silêncio eletromio-gráfico. O dinamômetro foi utilizado no modo concêntrico para determinar o torque total dos isquiossurais. O torque ativo foi obtido subtraindo-se o torque passivo do torque total. O ângulo do pico de torque ativo foi utilizado para a análise. RESULTADO: Não houve diferença estatisticamente significativa entre as duas medidas realizadas (t= 1,009; p= 0,323). O Coeficiente de Correlação Intraclasse para os valores obtidos do ângulo de pico de torque ativo foi de 0,948 (p= 0,0001; IC 95 por cento 0,881 - 0,977). CONCLUSÃO: O presente estudo demonstrou que o método descrito é confiável para a quantificação deste ângulo, sugerindo que este método pode ser utilizado para avaliar mudanças da curva torque-ângulo promovidas por alterações de comprimento muscular.


INTRODUCTION: Muscle length can be inferred from the length-tension relationship of the muscle. This relationship is traditionally investigated by measuring the peak torque produced by the muscle and the angle at which it is generated. OBJECTIVE: The present study investigated the test-retest reliability of a method for measuring hamstring active peak torque angle in healthy young adults. METHOD: Twenty-five healthy individuals (22.88 ± 1.67 years) were assessed twice with an interval of three weeks. An isokinetic dynamometer was used in passive mode to assess hamstring passive torque. Muscle activity was monitored to ensure electromyographic silence. The dynamometer was also used in concentric mode to determine hamstring total torque. The active torque was obtained as the difference between total torque and passive torque. The active peak torque angle was used for the analysis. RESULTS: There was no significant difference between the two measurements (t= 1.009; p= 0.323). The intraclass correlation coefficient for the active peak torque angle values obtained was 0.948 (p= 0.0001; 95 percent CI: 0.883 - 0.977). CONCLUSION: This study has shown that the method described is reliable for the quantification of active peak torque angle, thus suggesting that this method can be used to evaluate shifts in the torque-angle curve produced by muscle length changes.


Assuntos
Humanos , Masculino , Feminino , Músculos , Amplitude de Movimento Articular , Reprodutibilidade dos Testes , Torque
11.
J Exp Bot ; 58(3): 673-86, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17210990

RESUMO

Nitrogen-fixing bacteria have been isolated from sugarcane in an endophytic and beneficial interaction that promotes plant growth. In this work, for the first time, the involvement of ethylene signalling in this interaction was investigated by molecular characterizing members of this pathway in sugarcane. The expression pattern of a putative ethylene receptor (SCER1) and two putative ERF transcription factors (SCERF1 and SCERF2) show exclusive modulation in plants inoculated with the diazotrophic endophytes. The gene expression profile of SCER1, SCERF1, and SCERF2 is differentially regulated in sugarcane genotypes that can establish efficient or inefficient associations with diazotrophic micro-organisms, exhibiting high or low biological nitrogen fixation (BNF) rates, respectively. In addition, SCER1, SCERF1, and SCERF2 expression is different in response to interactions with pathogenic and beneficial micro-organisms. Taken together, that data suggest that SCER1, SCERF1, and SCERF2 might participate in specific ethylene signalling cascade(s) that can identify a beneficial endophytic association, modulating sugarcane responses toward the diazotrophic endophytes.


Assuntos
Etilenos/metabolismo , Gluconacetobacter/fisiologia , Herbaspirillum/fisiologia , Fixação de Nitrogênio , Proteínas de Plantas/metabolismo , Saccharum/microbiologia , Transdução de Sinais , Sequência de Aminoácidos , Etilenos/farmacologia , Etiquetas de Sequências Expressas , Regulação da Expressão Gênica de Plantas , Genótipo , Gluconacetobacter/metabolismo , Herbaspirillum/metabolismo , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Receptores de Superfície Celular/química , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Saccharum/genética , Saccharum/metabolismo , Fatores de Transcrição/química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
12.
J Exp Bot ; 57(3): 559-69, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16397001

RESUMO

Endophytic nitrogen-fixing bacteria have been isolated from graminaceous plants such as maize, rice, and sugarcane. They are thought to promote plant growth, not only by fixing nitrogen, but also by the production of plant hormones. The molecular mechanisms involved in this interaction are not yet clear. In this work, the identification of a receptor-like kinase (RLK), named SHR5, which may participate in signal transduction involved in the establishment of plant-endophytic bacteria interaction is described for the first time. SHR5 seems to be part of a novel subclass of RLKs present in a wide range of plant species. The expression of this gene is down-regulated in sugarcane plants associated exclusively with beneficial endophytic bacteria and is not a general response caused by micro-organisms or abiotic stress. In addition, more successful sugarcane-endophytic bacteria associations have a more pronounced decrease in SHR5 expression, suggesting that SHR5 mRNA levels in plant cells are inversely related to the efficiency of the association.


Assuntos
Bacilos e Cocos Aeróbios Gram-Negativos/fisiologia , Fixação de Nitrogênio/fisiologia , Fosfotransferases/metabolismo , Proteínas de Plantas/metabolismo , Saccharum/enzimologia , Saccharum/microbiologia , Actinobacteria/fisiologia , Sequência de Aminoácidos , Basidiomycota/fisiologia , DNA Complementar/genética , DNA Complementar/isolamento & purificação , Regulação para Baixo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genótipo , Ácidos Indolacéticos/farmacologia , Dados de Sequência Molecular , Fosfotransferases/genética , Filogenia , Proteínas de Plantas/genética , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Saccharum/genética , Análise de Sequência de Proteína , Cloreto de Sódio/farmacologia , Temperatura
13.
FEBS Lett ; 574(1-3): 192-202, 2004 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-15358564

RESUMO

Eukaryotic DNA replication requires an ordered and regulated machinery to control G1/S transition. The formation of the pre-replicative complex (pre-RC) is a key step involved in licensing DNA for replication. Here, we identify all putative components of the full pre-RC in the genome of the model plant Arabidopsis thaliana. Different from the other eukaryotes, Arabidopsis houses in its genome two putative homologs of ORC1, CDC6 and CDT1. Two mRNA variants of AtORC4 subunit, with different temporal expression patterns, were also identified. Two-hybrid binary interaction assays suggest a primary architectural organization of the Arabidopsis ORC, in which AtORC3 plays a central role in maintaining the complex associations. Expression profiles differ among pre-RC components suggesting the existence of various forms of the complex, possibly playing different roles during development. In addition, the expression of the putative pre-RC genes in non-proliferating plant tissues suggests that they might have roles in processes other than DNA replication licensing.


Assuntos
Arabidopsis/genética , Genoma de Planta , Sequência de Bases , Primers do DNA , Filogenia , Reação em Cadeia da Polimerase
14.
Mol Ecol ; 12(12): 3219-25, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14629340

RESUMO

Habitat fragmentation represents the single most serious threat to the survival of tropical ecosystems. In formulating strategies to counteract the detrimental effects of fragmentation, knowledge of the levels and patterns of genetic diversity within and between natural populations is vital to the establishment of any conservation programme. We utilized polymorphic chloroplast microsatellite markers to analyse genetic diversity in populations of the endangered tropical tree Caesalpinia echinata Lam. representing the entire extant range of the species. Levels of within-population diversity were low, with only two of seven populations studied displaying any variation. The vast majority of the genetic variation was partitioned between geographical regions (36%) and between populations within regions (55%). These levels of genetic structuring, coupled with a calculated pollen-to-seed flow ratio of approximately 6.7:1, suggest that there has been little gene flow between the three major geographical regions over an extended period. Thus, the current tripartite distribution of the species is more consistent with the existence of separate glacial refugia, rather than reflecting any anthropogenic effects.


Assuntos
Caesalpinia/genética , Meio Ambiente , Variação Genética , Geografia , Brasil , Caesalpinia/fisiologia , Análise por Conglomerados , Conservação dos Recursos Naturais , Primers do DNA , Haplótipos/genética , Repetições de Microssatélites/genética , Pólen/fisiologia , Sementes/fisiologia
15.
J Exp Bot ; 52(364): 2239-40, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11604464

RESUMO

Cdc6 is a key regulator of DNA replication in eukaryotes. In this work, the expression pattern of an Arabidopsis cdc6 homologue is characterized by RT-PCR and in situ hybridization. The data suggest that cdc6At expression is cell cycle regulated. During development, high cdc6At mRNA levels are found in regular cycling cells. In addition, cdc6At expression is also observed in cells that are probably undergoing endoreduplication, suggesting a possible role of Cdc6At in this process in plants.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Proteínas de Ciclo Celular/genética , Replicação do DNA , DNA de Plantas/genética , Sequência de Aminoácidos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiologia , Ciclo Celular/genética , Ciclo Celular/fisiologia , Regulação da Expressão Gênica de Plantas , Hibridização In Situ , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Distribuição Tecidual
16.
Mol Microbiol ; 40(6): 1357-69, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11442834

RESUMO

In the yeast Saccharomyces cerevisiae, Sup35p (eRF3), a subunit of the translation termination complex, can take up a prion-like, self-propagating conformation giving rise to the non-Mendelian [PSI+] determinant. The replication of [PSI+] prion seeds can be readily blocked by growth in the presence of low concentrations of guanidine hydrochloride (GdnHCl), leading to the generation of prion-free [psi-] cells. Here, we provide evidence that GdnHCl blocks seed replication in vivo by inactivation of the molecular chaperone Hsp104. Although growth in the presence of GdnHCl causes a modest increase in HSP104 expression (20-90%), this is not sufficient to explain prion curing. Rather, we show that GdnHCl inhibits two different Hsp104-dependent cellular processes, namely the acquisition of thermotolerance and the refolding of thermally denatured luciferase. The inhibitory effects of GdnHCl protein refolding are partially suppressed by elevating the endogenous cellular levels of Hsp104 using a constitutive promoter. The kinetics of GdnHCl-induced [PSI+] curing could be mimicked by co-expression of an ATPase-negative dominant HSP104 mutant in an otherwise wild-type [PSI+] strain. We suggest that GdnHCl inactivates the ATPase activity of Hsp104, leading to a block in the replication of [PSI+] seeds.


Assuntos
Proteínas Fúngicas/efeitos dos fármacos , Proteínas Fúngicas/metabolismo , Guanidina/farmacologia , Proteínas de Choque Térmico/metabolismo , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/fisiologia , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Temperatura Alta , Cinética , Luciferases/química , Luciferases/genética , Luciferases/metabolismo , Fatores de Terminação de Peptídeos , Príons/efeitos dos fármacos , Príons/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos
17.
J Biol Chem ; 276(42): 38353-60, 2001 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-11459835

RESUMO

Vaccinia virus (VV) triggers a mitogenic signal at an early stage of infection. VV-induced proto-oncogene c-fos mRNA with kinetics paralleling that stimulated by serum. The VV virokine, or vaccinia virus growth factor (VGF), was not crucial for c-fos induction because it was observed upon infection with the virokine-minus mutant VV (VGF(-)). Furthermore, c-fos expression did not require infectious virus particles, as it occurred even with UV-inactivated VV and was equally induced by the different multiplicities of infection, i.e. 1.0, 5.0, and 25.0. c-fos expression was preceded by VV-induced DNA binding activity and was mediated via the cis-acting elements serum response element (SRE), activating protein-1 (AP-1), and cAMP-response element (CRE). VV activated the protein kinases p42MAPK/ERK2 and p44MAPK/ERK1 and the transcription factor ATF1 in a time-dependent manner with kinetics that paralleled those of VV-stimulated DNA-protein complex formation. The mitogenic signal transmission pathways leading to c-fos activation upon VV infection were apparently mediated by the protein kinases MEK, ERK, and PKA. This assumption was based on the findings that: 1) c-fos transcript was down-regulated; 2) the SRE, AP-1, and CRE binding activities were significantly reduced; and 3) the activation of p42MAPK/ERK2, p44MAPK/ERK1, and ATF1 were drastically affected when the viral infections were carried out in the presence of specific protein kinase inhibitor. Moreover, the mutant VV (VGF(-)) was also able to activate ERK1/2. It is noteworthy that virus multiplication was equally affected by the same kinase inhibitors. Taken together, our data provide evidence that the early mitogenic signal triggered upon VV infection relies upon the activation of the protein kinases MEK, ERK, and PKA, which are needed for both signal transduction and virus multiplication.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mitógenos/metabolismo , Vaccinia virus/metabolismo , Vaccinia virus/patogenicidade , Animais , Northern Blotting , Western Blotting , Linhagem Celular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , DNA/metabolismo , DNA Complementar/metabolismo , Regulação para Baixo , Eletroforese em Gel de Poliacrilamida , Ativação Enzimática , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Cinética , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Endogâmicos BALB C , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Modelos Biológicos , Ligação Proteica , Proteínas Proto-Oncogênicas c-fos/metabolismo , RNA Mensageiro/metabolismo , Elemento de Resposta Sérica/genética , Transdução de Sinais , Fatores de Tempo , Transcrição Gênica
18.
J Clin Pathol ; 54(2): 103-6, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11215276

RESUMO

AIMS: Viral uveitis and retinitis, usually caused by herpesviruses, are common in immunosuppressed patients. The diagnosis of viral anterior uveitis and retinitis is usually clinical. The polymerase chain reaction (PCR) has been used for the diagnosis of some viral infections, especially those caused by herpesviruses. This paper reports the use of PCR in the diagnosis of viral retinitis in vitreous samples from Brazilian patients. METHODS: PCR was used for the diagnosis of necrotising retinitis in vitreous samples from patients from the Hospital São Geraldo, Universidade Federal de Minas Gerais, Brazil. The vitreous samples were collected by paracentesis and stored until analysis. Samples were analysed by PCR using specific primers designed to amplify herpes simplex virus 1 (HSV-1), varicella zoster virus (VZV), or human cytomegalovirus (HCMV). In a case of anterior uveitis, PCR was performed with a sample from the anterior chamber. RESULTS: Herpesvirus DNA was amplified in 11 of 17 samples. HCVM DNA was detected in nine samples but DNA from HSV-1 and VZV were detected only once each. CONCLUSION: These results strongly suggest that PCR could be used for a rapid complementary diagnosis of viral uveitis and retinitis. A prospective study to evaluate the PCR results, clinical evolution, and treatment is imperative to corroborate the real value of PCR in diagnosis and how it could help the clinicians' approach.


Assuntos
DNA Viral/análise , Infecções por Herpesviridae/diagnóstico , Reação em Cadeia da Polimerase/métodos , Retinite/virologia , Corpo Vítreo/virologia , Infecções Oportunistas Relacionadas com a AIDS/diagnóstico , Citomegalovirus/isolamento & purificação , Retinite por Citomegalovirus/diagnóstico , Herpesvirus Humano 1/isolamento & purificação , Herpesvirus Humano 3/isolamento & purificação , Humanos , Estudos Prospectivos , Uveíte Anterior/virologia
19.
Virus Genes ; 23(3): 291-301, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11778697

RESUMO

The lack of knowledge about the natural host of Vaccinia virus (VV) along with the description of human infections caused by poxviruses after smallpox eradication has increased the need to characterize poxviruses isolated from the wild. Moreover, in the past years poxviruses have been widely studied as potential vaccination tools, with the discovery of several genes implicated in the evasion of the host immune response involved in virus pathogenesis. Among them, an Interferon (IFN)-binding protein was identified in the supernatant of VV strain WR infected cells coded by the B18R gene. It was shown that many other Orthopoxviruses also encode and express this soluble receptor although some VV strains such as Lister and modified Ankara, which were less reactogenic vaccines, do not. The BeAn 58058 virus (BAV) has been recently characterized and proposed to be an Orthopoxvirus. BAV was also shown to be less virulent in animal models than VV Lister. Here we report the identification of an IFN-alpha/betaR gene in the BAV genome with 99% of sequence identity with the VVWR B18R gene. The identified gene encodes a B18R-like IFN binding protein as demonstrated by its capacity to inhibit the IFN-mediated protection of VERO cells against EMC virus. In order to better characterize the virus we have searched for the A type inclusion body (ATI) gene currently used in the classification of Orthopoxviruses but did not detect it in the BAV genome. We have also sequenced the BAV thymidine kinase (TK) gene, a poxvirus-conserved gene, which, as expected, showed high homology with the TK gene of other poxviruses. Phylogenetic trees were constructed based on sequences of the IFN-alpha/betaR and TK genes from several poxviruses and in both cases BAV was placed in the same cluster as other VV strains. These observations strengthened the hypothesis that this virus is a variant of the VV vaccine used in Brazil. However the explanation for the BAV lack of virulence remains to be discovered.


Assuntos
Orthopoxvirus/genética , Receptores de Interferon/genética , Timidina Quinase/genética , Proteínas Virais/genética , Sequência de Aminoácidos , Animais , Anticorpos Antivirais/imunologia , Sequência de Bases , Chlorocebus aethiops , DNA Viral , Genoma Viral , Corpos de Inclusão Viral/genética , Interferons/antagonistas & inibidores , Proteínas de Membrana , Dados de Sequência Molecular , Testes de Neutralização , Orthopoxvirus/imunologia , Orthopoxvirus/patogenicidade , Receptor de Interferon alfa e beta , Receptores de Interferon/química , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Células Vero , Proteínas Virais/química
20.
Eur J Neurosci ; 12(12): 4367-80, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11122347

RESUMO

The rat melanin-concentrating hormone (MCH) gene may produce, through alternative splicing, either the precursor of MCH and neuropeptide EI, two neuropeptides coexpressed in the zona incerta (ZI) and lateral hypothalamus (LHA), or a putative protein we named previously MCH-gene-overprinted-polypeptide (MGOP). First, we investigated the distribution and relative expression of MCH and MGOP mRNA in the rat brain by Northern blotting, RT-PCR and in situ hybridization. MGOP gene transcripts were detected mainly in the hypothalamus only by RT-PCR. Second, different antisera were raised toward the C-terminus of MGOP and used to identify the translational products. In the rat brain, no MGOP-processed peptide could be detected based on RP-HPLC coupled to specific RIA. A polypeptide of 14 kDa was found in the secretory pathway of transfected monkey COS7 cells expressing recombinant MGOP. In the rat hypothalamus, a specific protein of 12 kDa was identified by Western blot analysis. Finally, distribution of MGOP-immunoreactivity (IR) was investigated in the rat brain. Colocalization studies demonstrated that 98% of the MGOP-expressing perikarya in ZI/LHA also synthesized MCH. In addition, numerous, strongly stained MGOP-containing neurons were encountered in the hypothalamic periventricular nucleus. Perikarya labelled with MGOP antiserum were also found scattered in the cortex, caudate putamen, amygdala and lateral septal nucleus. MCH was not detected in these MGOP-containing neurons. Strikingly, dense staining of terminals was observed with MGOP antiserum but not with MCH antibodies in the suprachiasmatic, ventromedial and arcuate nuclei, and also in the external layer of the median eminence. These results demonstrated that MGOP and MCH-IR overlapped in LHA/ZI but displayed a differential distribution in other areas. Based on this cerebral distribution, MGOP may act as a new secreted protein in regulating many neuroendocrine functions, such as nursing, feeding and growth control in associated behavioural components.


Assuntos
Encéfalo/fisiologia , Hormônios Hipotalâmicos/genética , Melaninas/genética , Proteínas do Tecido Nervoso/genética , Neurônios/fisiologia , Hormônios Hipofisários/genética , Transcrição Gênica , Sequência de Aminoácidos , Animais , Encéfalo/citologia , Células COS , Linhagem Celular , Hormônios Hipotalâmicos/análise , Íntrons , Masculino , Melaninas/análise , Dados de Sequência Molecular , Neurônios/citologia , Especificidade de Órgãos , Hormônios Hipofisários/análise , RNA Mensageiro/análise , RNA Mensageiro/genética , Ratos , Ratos Wistar , Proteínas Recombinantes/análise , Proteínas Recombinantes/biossíntese , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Spodoptera , Transfecção
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