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1.
J Eur Acad Dermatol Venereol ; 36(11): 1980-1990, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35857381

RESUMO

Atopic dermatitis (AD) is a chronic skin disease that significantly impacts patient quality of life (QoL). It is unknown whether patients and physicians have the same interpretation of AD burden. Unmet needs and AD disease burden were evaluated by comparing terminology used in social media with terminology used in scientific literature. AD terminology in social media was identified using the NetBase platform, and natural language processing was performed. Topics and words driving negative sentiment were evaluated overall and in relation to specific symptoms. The systematic review of scientific literature identified publications that included AD and QoL terms was identified from PubMed. Term analysis of titles and abstracts was conducted via natural language processing. The occurrence of topics and co-occurrence of words associated with QoL terms were evaluated. More than 3 million social media mentions (2018-2020) and 1519 scientific publications (2000-2020) were evaluated. There were more negative than positive social media mentions, and flare and pain were common symptoms driving negative sentiment. Face and hands were major drivers of negative sentiment in relation to AD symptoms in social media. Sleep and pain were often mentioned together. In scientific literature, pruritus and depression were the most frequently occurring symptoms. Similarly, pruritus was the most common AD symptom co-occurring with QoL terms in the assessed scientific literature. Social media analyses provide a unique view into the patient experience of AD. Symptoms driving negative sentiment in social media appear to be discordantly represented in scientific literature. Incorporating patient perspectives may improve disease understanding and management.


Assuntos
Dermatite Atópica , Mídias Sociais , Humanos , Dor , Prurido/etiologia , Qualidade de Vida
2.
ScientificWorldJournal ; 2013: 634738, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24453885

RESUMO

Application of microbial fuel cells (MFCs) to wastewater treatment for direct recovery of electric energy appears to provide a potentially attractive alternative to traditional treatment processes, in an optic of costs reduction, and tapping of sustainable energy sources that characterizes current trends in technology. This work focuses on a laboratory-scale, air-cathode, and single-chamber MFC, with internal volume of 6.9 L, operating in batch mode. The MFC was fed with different types of substrates. This study evaluates the MFC behaviour, in terms of organic matter removal efficiency, which reached 86% (on average) with a hydraulic retention time of 150 hours. The MFC produced an average power density of 13.2 mW/m(3), with a Coulombic efficiency ranging from 0.8 to 1.9%. The amount of data collected allowed an accurate analysis of the repeatability of MFC electrochemical behaviour, with regards to both COD removal kinetics and electric energy production.


Assuntos
Fontes de Energia Bioelétrica , Reforma Urbana , Águas Residuárias/química , Purificação da Água/métodos , Técnicas Eletroquímicas/métodos
3.
Eur J Histochem ; 49(2): 107-15, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15967738

RESUMO

The pattern of expression of a carrot dhfr-ts gene was evaluated in different plant organs, in somatic embryos, and in hypocotyl explants induced to dedifferentiate in vitro by the addition of the synthetic auxin 2,4 dichorophenoxyacetic acid. The promoter of this gene was also placed upstream of a uidA (GUS) reporter gene and, using biolistic and protoplasts transient expression assays, was shown to drive a particularly high level of expression in actively growing suspension cells. The results from these expression analyses combined with the presence of putative cell cycle-related cis-acting elements in the dhfr-ts promoter, strongly point to a cell division-dependent expression of this gene.


Assuntos
Daucus carota/enzimologia , Regulação da Expressão Gênica de Plantas/genética , Tetra-Hidrofolato Desidrogenase/genética , Timidilato Sintase/genética , Linhagem Celular , Proliferação de Células , Daucus carota/genética , Daucus carota/crescimento & desenvolvimento , Regulação Enzimológica da Expressão Gênica/genética , Hibridização In Situ , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Tetra-Hidrofolato Desidrogenase/metabolismo , Timidilato Sintase/metabolismo
4.
Mol Genet Genomics ; 266(6): 995-1003, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11862494

RESUMO

In eukaryotes, transcription factors of the E2F family, in addition to having a role in cell proliferation, participate in regulating apoptosis, differentiation and development. In Arabidopsis thaliana, eight gene sequences have been identified as encoding E2F or DP homologues. DP proteins form heterodimers with E2Fs. The aim of this work was to characterize the functions of three of these factors: AtE2F-a, AtE2F-b and AtDP-a. Here we report that AtE2F-a and AtE2F-b transactivate a reporter gene via an E2F consensus cis-acting element in Arabidopsis protoplasts. AtE2F-a is a more potent activator than AtE2F-b. Furthermore, co-expression of the E2F partner AtDP-a, or the DNA binding protein AtPur alpha, modulates the activation of AtE2F-a. Taken together, these results suggest that AtE2F-a, AtE2F-b and AtDP-a share features characteristic of members of the E2F family of transcription factors. Moreover, over-expression of AtE2F-a and AtDP-a can induce differentiated, non-dividing, leaf cells to re-enter S-phase. We conclude that the transcription factor AtE2F-a plays an important role in progression into S phase, which probably correlates with its capacity to stimulate transcription.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Folhas de Planta/fisiologia , Fase S/fisiologia , Fatores de Transcrição/fisiologia , Arabidopsis/citologia , Proteínas de Arabidopsis/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/fisiologia , Fatores de Transcrição E2F , Glucuronidase/genética , Glucuronidase/metabolismo , Folhas de Planta/citologia , Folhas de Planta/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , Protoplastos/citologia , Protoplastos/fisiologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Fatores de Transcrição/genética , Ativação Transcricional
5.
J Biol Chem ; 275(25): 19258-67, 2000 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-10748129

RESUMO

In animal cells the progression of the cell cycle through G(1)/S transition and S phase is under the control of the pRB/E2F regulatory pathway. The E2F transcription factors are key activators of genes coding for several regulatory proteins and for enzymes involved in nucleotide and DNA synthesis. In this report we have detected the presence of E2F-like DNA binding activities in carrot nuclear extracts, and we have isolated a carrot cDNA (DcE2F) encoding a plant E2F homologue. The DcE2F gene is expressed in proliferating cells and is induced during the G(1)/S transition of the cell cycle. Supershift experiments using anti-DcE2F antiserum have confirmed that the DcE2F protein is a component of the carrot E2F-like nuclear activities. DNA binding assays have demonstrated that the DcE2F protein can recognize a canonical E2F cis-element in association with a mammalian DP protein. Furthermore, transactivation assays have revealed that DcE2F is a functional transcription factor that can transactivate, together with a DP partner, an E2F-responsive reporter gene in both plant and mammalian cells.


Assuntos
Proteínas de Transporte , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Daucus carota/metabolismo , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Ciclo Celular , DNA Complementar , Daucus carota/citologia , Fatores de Transcrição E2F , Dados de Sequência Molecular , Proteína 1 de Ligação ao Retinoblastoma , Homologia de Sequência de Aminoácidos , Transativadores/química , Transativadores/genética , Fatores de Transcrição/química , Fatores de Transcrição/genética
6.
Mol Ecol ; 9(2): 229-32, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10672167

RESUMO

The random amplified polymorphic DNA (RAPD) technique was applied to settle a lawsuit involving unauthorized commercialization of a patented strawberry variety of high economical relevance ('Marmolada'). Because of economical involvements, the molecular approach was added to the more traditional morphological examination in a double-blind test. All plants belonging to the patented variety were unambiguously identified (13 plants among a total of 31 plants examined). The results were accepted as evidence in the court. This study confirms that the RAPD technique is especially suitable for identification of asexually reproduced plant varieties for forensic or agricultural purposes.


Assuntos
Frutas/classificação , Frutas/genética , Patentes como Assunto , Técnica de Amplificação ao Acaso de DNA Polimórfico , Marcadores Genéticos
7.
J Exp Bot ; 51(353): 1979-90, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11141172

RESUMO

Five DNA topoisomerase I cDNA clones were isolated from a carrot (Daucus carota) cDNA library and two classes of nucleotide sequences were found. One component of the first class, pTop9, perfectly matches the open reading frame of pTop28, a truncated top1 cDNA previously described, and extended it by 594 nucleotides (top1alpha). A member of the second class, pTop11, contains an open reading frame 2727 bp long (top1ss) with a coding capacity for a second putative DNA topoisomerase I of 101 kDa. Both pTop9 and pTop11 clones are full length cDNAs. The two deduced amino acid sequences share a relevant similarity (89%) only at the C-terminal domain, whereas the similarity is reduced to 32% in the N-terminal region. Southern blot analysis and PCR amplification of genomic DNAs from carrot pure lines suggested the presence of two distinct loci. Northern blot analysis revealed the presence of two distinct transcripts of 3.0 and 3.2 kb in both cycling and starved cell populations. Three fusion peptides corresponding to the N-terminal domain of the alpha and ss forms and from the common C-terminal domain of carrot topoisomerases I were overexpressed in E. coli cells and used to raise antibodies in rabbit. Immunolocalization seems to suggest the presence of two topoisomerases I in carrot nuclei.


Assuntos
DNA Topoisomerases Tipo I/genética , Daucus carota/enzimologia , Sequência de Aminoácidos , Southern Blotting , Western Blotting , Linhagem Celular , Clonagem Molecular , DNA Complementar , DNA de Plantas/metabolismo , Daucus carota/genética , Escherichia coli , Expressão Gênica , Genes de Plantas , Dados de Sequência Molecular , Fases de Leitura Aberta , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo
8.
Minerva Anestesiol ; 64(4): 189-91, 1998 Apr.
Artigo em Italiano | MEDLINE | ID: mdl-9773654

RESUMO

Intracranial haemorrhage from ruptured aneurysm or bleeding in arteriovenous malformation is rare, but may result in significant maternal and fetal mortality and serious neurological morbidity in survivors. Surgical intervention creates risks for the mother and her fetus, but is the best form of management. The anaesthetic procedure can present many clinical dilemmas, one of which is the role of induced hypotension. This review will focus on the diagnosis and management of this dramatic event.


Assuntos
Complicações Cardiovasculares na Gravidez/cirurgia , Hemorragia Subaracnóidea/complicações , Hemorragia Subaracnóidea/cirurgia , Feminino , Humanos , Gravidez
9.
Plant J ; 13(3): 317-29, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9680985

RESUMO

In the present study, the isolation and characterization of two distinct cDNAs that code for carrot DNA (cytosine-5)-methyltransferase (DNA-METase) are reported. The screening of a cDNA library with a carrot genomic DNA fragment, previously obtained by PCR using degenerate primers, has led to the isolation of clones that belong to two distinct classes of genes (Met1 and Met2) which differ in sequence and size. Met1-5 and Met2-21 derived amino acid sequences are more than 85% identical for most of the polypeptide and completely diverge at the N-terminus. The larger size of the Met2-21 cDNA is due to the presence of nearly perfect fivefold repeat of a 171 bp sequence present only once in the Met1-5 cDNA. Northern and in situ hybridization analyses with young carrot plants and somatic embryos indicate that both genes are maximally expressed in proliferating cells (suspension cells, meristems and leaf primordia), but differ quantitatively and spatially in their mode of expression. Polyclonal antibodies were raised in rabbit using fusion proteins corresponding to the regulatory and catalytic regions of the most highly expressed gene (Met1-5). In nuclear carrot extracts, both antibodies were found to recognize a band of about 200 kDa along with some additional bands of lower size. These results provide the first direct demonstration that DNA-METases of a higher eukaryote are encoded by a gene family.


Assuntos
DNA (Citosina-5-)-Metiltransferases/genética , Daucus carota/enzimologia , Daucus carota/genética , Genes de Plantas , Sequência de Aminoácidos , Animais , Anticorpos , Sequência de Bases , DNA (Citosina-5-)-Metiltransferases/imunologia , Primers do DNA/genética , DNA Complementar/genética , DNA Complementar/isolamento & purificação , DNA de Plantas/genética , DNA de Plantas/isolamento & purificação , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Hibridização In Situ , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Coelhos , Sequências Repetitivas de Ácido Nucleico , Homologia de Sequência de Aminoácidos
10.
Plant Mol Biol ; 34(2): 325-30, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9207848

RESUMO

The present study describes the isolation of a cDNA coding for a carrot protein of 450 amino acids that contains WD repeats (DcWD1) and is homologous to Drosophila melanogaster fizzy protein, mammalian p55CDC and yeast Cdc20p. As for the known related proteins, sequence conservation concerned the majority of the polypeptide except the far N-terminus. Results of Southern blot analysis with genomic DNA under high stringency conditions showed the occurrence of a single gene. Northern blot analyses revealed the accumulation of DcWD1 mRNA in all tested tissues (leaves, petioles and hypocotyls, apical meristems, roots and suspension cultured cells), though at a different extent. Lack of induction of relevant transcripts in proliferating auxin-stimulated hypocotyls suggests a mode of expression not strictly related to the cell proliferation.


Assuntos
Proteínas de Ciclo Celular/genética , DNA Complementar/isolamento & purificação , Daucus carota/genética , Proteínas de Drosophila , Proteínas de Plantas/genética , Proteínas de Saccharomyces cerevisiae , Homologia de Sequência de Aminoácidos , Sequência de Aminoácidos , Animais , Proteínas Cdc20 , Proteínas de Ciclo Celular/biossíntese , Proteínas de Ciclo Celular/química , Clonagem Molecular , DNA Complementar/química , Daucus carota/química , Drosophila melanogaster , Dosagem de Genes , Humanos , Dados de Sequência Molecular , Proteínas de Plantas/biossíntese , Proteínas de Plantas/química , Proteínas/química , Proteínas/genética , Sequências Repetitivas de Ácido Nucleico , Saccharomyces cerevisiae
11.
Plant Mol Biol ; 33(4): 709-22, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9132062

RESUMO

The analysis of clones obtained by rapid amplification of the 5' end and by primer extension of the mRNA for carrot bifunctional dihydrofolate reductase-thymidylate synthase showed transcripts of differing lengths that belonged to two sub-populations. The longer transcripts were found to contain a translation start site 147 nt upstream of, and in frame with, the one which is present in the shorter transcripts. The ORF that begins at this ATG codes for a protein of 64714 Da, which is much larger than mature DHFR-TS subunit. The N-terminus region of this polypeptide shows features typical of plant transit peptides. Immunogold labelling studies and immunorecognition of the plastid-containing sub-cellular fraction suggested a plastidial localisation of the bifunctional protein. Although plant cells were shown to contain folate pools in plastids, in mitochondria and in the cytosol, few enzymes of the folate pathway have been associated with any sub-cellular compartment. Thus, this is the first indication for the presence of an enzyme of the folate biosynthetic pathway in plastids. The longer transcripts revealed the presence of a TC microsatellite at the 5'-untranslated end.


Assuntos
Compartimento Celular , Daucus carota/genética , Genes de Plantas , Complexos Multienzimáticos/genética , Tetra-Hidrofolato Desidrogenase/genética , Timidilato Sintase/genética , Transcrição Gênica , Sequência de Aminoácidos , Sequência de Bases , Daucus carota/enzimologia , Repetições de Dinucleotídeos , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Complexos Multienzimáticos/isolamento & purificação , Plastídeos/enzimologia , Polimorfismo Genético , Precursores de Proteínas/genética , RNA Mensageiro/genética , RNA de Plantas/genética , Análise de Sequência , Tetra-Hidrofolato Desidrogenase/isolamento & purificação , Timidilato Sintase/isolamento & purificação
13.
Thromb Haemost ; 75(3): 393-4, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8701395

RESUMO

To evaluate the association between coagulation defects and cerebral venous thrombosis, a case-control study was conducted in 25 patients who had no autoimmune, neoplastic or infections disease and 75 healthy individuals. There were no patients with deficiency of protein C or protein S. Four had resistance to activated protein C (APC) and one had APC resistance associated with antithrombin deficiency. APC resistance was investigated by DNA analysis, and diagnosed by the presence of a point mutation in the factor V gene, which predicts replacement of Arg506 with Gln at one of the two APC cleavage sites in activated factor V. The prevalence of APC resistance was 20% in patients and 2.7% in controls. This difference was statistically significant (p = 0.01) and the odds ratio was 9.1. A circumstantial factor predisposing to cerebral venous thrombosis (such as oral contraceptive intake, pregnancy, puerperium, trauma or prolonged immobilization) was reported in 72% of cases. In conclusion, APC resistance is the most frequent coagulation abnormality associated with cerebral venous thrombosis.


Assuntos
Fator V/genética , Embolia e Trombose Intracraniana/genética , Adulto , Sequência de Bases , Veias Cerebrais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Mutação , Gravidez , Deficiência de Proteína C , Estudos Retrospectivos , Fatores de Risco
14.
Gene ; 140(1): 59-62, 1994 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-8125339

RESUMO

A simple and efficient method is described for the isolation of extension fragments of known DNA sequences by polymerase chain reaction (PCR) using a single specific primer. With this method, size-selected genomic DNA fragments are ligated to a plasmid vector (pGEM-4Z) which contains sequencing primers and the population of chimeric plasmids is used for transforming Escherichia coli. DNA is extracted from an aliquot of the resulting mini-library and PCR performed using a sequence-specific primer and either of the standard sequencing primers of the plasmid vector. This method appears to be more versatile than inverse PCR (IPCR), since: (i) the DNA sequence needed as the specific primer can be as short as about 20 nucleotides (nt); (ii) the DNA templates to be used in PCR are available in high amount, thus facilitating all manipulations; and (iii) if relinearization of the DNA by restriction enzyme digestion is desired before the PCR reaction, many restriction sites can be chosen from the vector polylinker. Using this method, we have isolated the genomic 5' region of the carrot bifunctional dihydrofolate reductase-thymidylate synthase-encoding gene dhfr-ts using a 21-nt sequence of the 5' region of the dhfr-ts cDNA clone as the specific primer.


Assuntos
Complexos Multienzimáticos/genética , Reação em Cadeia da Polimerase/métodos , Sequências Reguladoras de Ácido Nucleico , Tetra-Hidrofolato Desidrogenase/genética , Timidilato Sintase/genética , Sequência de Bases , Sítios de Ligação , DNA Bacteriano/isolamento & purificação , DNA Bacteriano/metabolismo , DNA Complementar/metabolismo , Escherichia coli/genética , Dados de Sequência Molecular , Plasmídeos , Moldes Genéticos
15.
Plant Mol Biol ; 24(2): 327-40, 1994 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8111035

RESUMO

In Brassica napus, oleosins are expressed at high levels in the seed during the latter stages of embryo development. The cis-acting regulatory properties of an 872 bp promoter fragment of a B. napus oleosin gene were examined by analysis of beta-glucuronidase (GUS) expression in transgenic tobacco plants containing an oleosin promoter-GUS transcriptional fusion. The reporter gene was expressed at high levels only in seeds, specifically in embryo and endosperm tissue and regulated throughout seed development. These data demonstrate that oleosin gene transcription is regulated in a tissue-specific and temporally regulated manner and clearly indicate that oleosin protein expression is co-ordinated primarily at the transcriptional level. Oleosin mRNA was shown to be abscisic acid (ABA) inducible and an ABA-response element in the oleosin promoter was shown to be bound by a protein factor in a sequence-specific manner. Sequence analysis of the oleosin promoter has identified several other putative cis-acting sequences which may direct oleosin gene expression. The presence of a large open reading frame in the bottom strand of the oleosin promoter (ORF2) which encodes a polypeptide similar to the ethylene-induced E4 gene of tomato is reported. A PCR-generated DNA probe containing the ORF2 sequence hybridised with a 1.4 kb transcript in total RNA extracts of a variety of tissues, including leaves and germinated seed cotyledons. This finding suggests that the oleosin gene promoter directs transcription in both directions. It is the first report of a bi-directional nuclear gene promoter in plants.


Assuntos
Brassica/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas , Sementes/metabolismo , Sequência de Aminoácidos , Sequência de Bases , DNA , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica , Guanosina/metabolismo , Dados de Sequência Molecular , Fases de Leitura Aberta , Sequências Reguladoras de Ácido Nucleico , Homologia de Sequência de Aminoácidos
16.
Plant Mol Biol ; 22(3): 427-35, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8329682

RESUMO

Molecular cloning of dihydrofolate reductase-thymidylate synthase (DHFR-TS) of Daucus carota was achieved by immunoscreening of a cDNA library obtaining a 2 kbp clone which contains an open reading frame of 1528 bp. Comparison of the deduced amino acid sequence with those from other sources revealed the presence of motifs typical of DHFR and TS thus confirming the bifunctional nature of the carrot protein. As in other organisms, a higher degree of conservation was observed in the TS domain. Analysis of the dhfr-ts gene content in carrot revealed the presence of several copies per diploid genome.


Assuntos
Complexos Multienzimáticos/genética , Plantas/enzimologia , Plantas/genética , Tetra-Hidrofolato Desidrogenase/genética , Timidilato Sintase/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Leishmania tropica/enzimologia , Dados de Sequência Molecular , Família Multigênica , Filogenia , Homologia de Sequência de Aminoácidos
17.
Plant Mol Biol ; 16(6): 975-82, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1863769

RESUMO

The bifunctional dihydrofolate reductase-thymidylate synthase (DHFR-TS) of Daucus carota has been further characterized as regards molecular weight, amino acid composition, protease digestion and microsequencing of proteolytic peptides. Data reported in this paper demonstrate that the carrot protein has a calculated Mr of 124,000 thus indicating that, contrarily to what has previously been suggested, it occurs as a dimer of identical subunits. Results of partial amino acid microsequencing show the presence of sequences highly homologous with those of the active sites of both DHFR and TS from other organisms confirming, at the structural level, the bifunctional nature of the carrot protein. As in the case of Leishmania tropica DHFR-TS, incubation of the carrot protein with V8 protease led to a rapid loss of TS activity while retaining that of DHFR. However the pattern of proteolysis did not allow to establish whether the sequence of domains is DHFR-TS as in Leishmania, or vice versa. Low homology of other amino acid sequences, as judged by computer analysis, and absence of common epitopes indicate an apparent divergence between carrot and leishmanian proteins.


Assuntos
Plantas/enzimologia , Tetra-Hidrofolato Desidrogenase/química , Timidilato Sintase/química , Sequência de Aminoácidos , Animais , Western Blotting , Cinética , Leishmania tropica/enzimologia , Substâncias Macromoleculares , Dados de Sequência Molecular , Homologia de Sequência do Ácido Nucleico , Serina Endopeptidases/metabolismo , Tetra-Hidrofolato Desidrogenase/metabolismo , Timidilato Sintase/metabolismo
18.
Biochem Biophys Res Commun ; 177(2): 711-9, 1991 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-2049093

RESUMO

DNA methyltransferase activity has been observed in a total crude homogenate of rice cells grown in suspension culture using either native plant DNA or, under the conditions used, the more responsive hemimethylated poly (dI-MedC).poly(dI-dC). Using the latter substrate we have purified an enzyme fraction 380-fold by salt extraction of chromatin, DEAE cellulose and phosphocellulose. This purified fraction showed enzyme activity only with poly (dI-MedC).poly(dI-dC) thus suggesting the occurrence in plants of a DNA methyltransferase specific for hemimethylated DNA. A Mr value of 54000 was calculated on the basis of the sedimentation coefficient which was determined by sucrose density gradient centrifugation. Apparent Km values for poly (dI-MedC).poly(dI-dC) and S-adenosyl-L-methionine were found to be 17 micrograms/ml and 2.6 microM, respectively.


Assuntos
Metilases de Modificação do DNA/isolamento & purificação , Oryza/enzimologia , Células Cultivadas , Centrifugação com Gradiente de Concentração , Cromatina/enzimologia , Cromatografia por Troca Iônica , Metilases de Modificação do DNA/química , Estabilidade Enzimática , Cinética , Polidesoxirribonucleotídeos/metabolismo , S-Adenosilmetionina/metabolismo , Especificidade por Substrato
19.
Eur J Basic Appl Histochem ; 35(1): 61-71, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1863664

RESUMO

The intracellular distribution and localization of dihydrofolate reductase-thymidylate synthase of wild type suspension carrot cells was analysed using cytochemical and immunocytochemical techniques; in both resting and growing normal cells (E4) the activity appeared to be predominantly cytoplasmic. The pattern of localization of the enzyme was also analysed during the different phases of the cell cycle. To this end carrot cells were synchronized with aphidicolin (an inhibitor of the alpha-like DNA polymerase which blocks cells at the G1/S boundary) and cycle phases checked by labelled-thymidine incorporation. Protoplasts obtained from cells inhibited with aphidicolin or from cells sampled at different times after the removal of the drug (S and G2 phase), failed to show a nuclear localization of DHFR-TS. These results indicate that in carrot the bifunctional enzyme does not change compartment during the cell cycle. Surprisingly Mtx-resistant cells (E2A2, E2A1C6; overproducing DHFR-TS) showed, irrespective of their physiological state (quiescent or growing), also a relevant nuclear or perinuclear immunofluorescence which could not be detected using cytochemical techniques. The reason of this altered localization is not clear and its possible relation with altered cytophysiological parameters is discussed.


Assuntos
Complexos Multienzimáticos/análise , Plantas/enzimologia , Tetra-Hidrofolato Desidrogenase/análise , Timidilato Sintase/análise , Ciclo Celular , Células Cultivadas , DNA/análise , Citometria de Fluxo , Imunofluorescência , Plantas/genética , Protoplastos/enzimologia
20.
Plant Cell Rep ; 10(6-7): 315-20, 1991 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24221664

RESUMO

The availability of a substantial amount of high molecular weight DNA is an essential prerequisite for the construction of yeast artificial chromosome (YAC) libraries. Parameters concerning protoplast isolation and DNA extraction have been systematically analyzed. Conditions have been established for the obtainment of high molecular weight DNA from Arabidopsis thaliana and Nicotiana plumbaginifolia protoplasts either embedded in agarose plugs or in liquid suspension. Restriction fragments were obtained by partial and total digestion with different endonucleases, and separated by pulsed-field gel electrophoresis. Ligation of partially EcoRI-digested DNA (range 30-300 kbp) followed by transformation of yeast spheroplasts gave rise to YACs with an average size of 60 kbp. The introduction of a DNA size-selection step before ligation led to production of YACs in the range of 100-200 kbp. Clones of up to 460 kbp were obtained by blunt-end ligation of pre-selected unrestricted DNA.

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