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1.
Breast Cancer Res Treat ; 178(3): 557-564, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31512090

RESUMO

PURPOSE: In order to better define the breast cancer (BC) genetic risk factors in men, a germline investigation was carried out on 81 Male BC cases by screening the 24 genes involved in BC predisposition, genome stability maintenance and DNA repair mechanisms by next-generation sequencing. METHODS: Germline DNAs were tested in a custom multi-gene panel focused on all coding exons and exon-intron boundaries of 24 selected genes using two amplicon-based assays on PGM-Ion Torrent (ThermoFisher Scientific) and MiSeq (Illumina) platforms. All variants were recorded and classified by using a custom pipeline. RESULTS: Clinical pathological data and the family history of 81 Male BC cases were gathered and analysed, revealing the average age of onset to be 61.3 years old and that in 35 cases there was a family history of BC. Our genetic screening allowed us to identify a germline mutation in 22 patients (23%) in 4 genes: BRCA2, BRIP1, MUTYH and PMS2. Moreover, 12 variants of unknown clinical significance (VUS) in 9 genes (BARD1, BRCA1, BRIP1, CHEK2, ERCC1, NBN, PALB2, PMS1, RAD50) were predicted as potentially pathogenic by in silico analysis bringing the mutation detection rate up to 40%. CONCLUSION: As expected, a positive family history is a strong predictor of germline BRCA2 mutations in male BC. Understanding the potential pathogenicity of VUS represents an extremely urgent need for the management of BC risk in Male BC cases and their own families.


Assuntos
Neoplasias da Mama Masculina/genética , Reparo do DNA/genética , Predisposição Genética para Doença/genética , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas de Neoplasias/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama Masculina/sangue , Neoplasias da Mama Masculina/patologia , Testes Genéticos , Genoma Humano/genética , Mutação em Linhagem Germinativa , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem
2.
Anaesthesia ; 74(6): 741-750, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30835822

RESUMO

Peri-operative dexmedetomidine can reduce rates of delirium immediately after surgery. We aimed to assess the effect of dexmedetomidine on cognition up to six postoperative months and its association with changes in serum concentrations of brain-derived neurotrophic factor on the third and seventh postoperative days. We randomly allocated 535 patients aged 65 years or more undergoing scheduled gastro-intestinal laparotomy to: intra-operative dexmedetomidine, 0.5 µg.kg-1 bolus followed by 0.4 µg.kg-1 .hr-1 infusion (n = 269), or placebo (n = 266). Dexmedetomidine reduced the rate of cognitive impairment: on the third postoperative day, 40/269 vs. 65/266, p = 0.006; on the seventh postoperative day, 31/269 vs. 49/266, p = 0.03 and at one postoperative month, 42/250 vs. 61/248, p = 0.04. Cognitive impairment at seven postoperative days was associated with changes in brain-derived neurotrophic factor concentrations on the third and seventh postoperative days; area under the receiver operating characteristic curve 0.63, p < 0.001 and 0.58, p = 0.016, respectively. Intra-operative dexmedetomidine reduced cognitive decline up to one postoperative month in elderly patients undergoing scheduled laparotomy, which was associated with changes in serum brain-derived neurotrophic factor.


Assuntos
Disfunção Cognitiva/prevenção & controle , Dexmedetomidina/farmacologia , Hipnóticos e Sedativos/farmacologia , Cuidados Intraoperatórios/métodos , Complicações Pós-Operatórias/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Fator Neurotrófico Derivado do Encéfalo/sangue , Disfunção Cognitiva/sangue , Feminino , Humanos , Masculino , Complicações Pós-Operatórias/sangue , Estudos Prospectivos
3.
Tissue Antigens ; 78(3): 178-84, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21810082

RESUMO

To assess the potential contribution of major histocompatibility complex class I chain-related gene A (MICA) polymorphisms toward the pathogenesis of leukemia, 107 leukemia patients and 162 ethnically matched controls from Hunan province, Southern China, were genotyped for the MICA polymorphism using polymerase chain reaction-sequence-specific priming (PCR-SSP) and sequence-based typing (PCR-SBT). The relevance between these genotypes and risk of leukemia was assessed by means of odds ratio (OR) with 95% confidence intervals (95% CIs). Allele frequencies of MICA-sequence and MICA-STR were different in leukemia patients in comparison with normal controls (both P < 0.05). MICA A5 was directly associated with leukemia (OR = 2.3257, Pc < 0.0005), whereas MICA A5.1 and MICA*008 were inversely associated with leukemia (OR = 0.5874, Pc = 0.0235 and OR = 0.5874, Pc = 0.0329, respectively). In addition, we found that homozygotes for MICA A5 (OR = 14.0659, 95% CI: 3.1627-62.5574, Pc < 0.0001) and MICA*010 (OR = 10.1053, 95% CI: 2.2139-46.1260, Pc < 0.0004) were at an increased risk for leukemia, whereas heterozygotes for MICA*008 and MICA A5.1 were linked to a decreased risk for leukemia (OR = 0.4609, 95% CI: 0.2799-0.7590, Pc = 0.0027). MICA allelic variation is associated with leukemia in Hunan Han population; the data also suggest that MICA gene polymorphism affects susceptibility to different clinical subtypes of leukemia.


Assuntos
Etnicidade/genética , Predisposição Genética para Doença , Antígenos de Histocompatibilidade Classe I/genética , Leucemia/genética , Polimorfismo Genético/genética , Adulto , Estudos de Casos e Controles , China , Feminino , Frequência do Gene , Genótipo , Humanos , Leucemia/classificação , Masculino , Repetições de Microssatélites , Reação em Cadeia da Polimerase
4.
Oncogene ; 28(19): 2034-45, 2009 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-19363524

RESUMO

We report that artemin, a member of the glial cell line-derived neurotrophic factor family of ligands, is oncogenic for human mammary carcinoma. Artemin is expressed in numerous human mammary carcinoma cell lines. Forced expression of artemin in mammary carcinoma cells results in increased anchorage-independent growth, increased colony formation in soft agar and in three-dimensional Matrigel, and also promotes a scattered cell phenotype with enhanced migration and invasion. Moreover, forced expression of artemin increases tumor size in xenograft models and leads to highly proliferative, poorly differentiated and invasive tumors. Expression data in Oncomine indicate that high artemin expression is significantly associated with residual disease after chemotherapy, metastasis, relapse and death. Artemin protein is detectable in 65% of mammary carcinoma and its expression correlates to decreased overall survival in the cohort of patients. Depletion of endogenous artemin with small interfering RNA, or antibody inhibition of artemin, decreases the oncogenicity and invasiveness of mammary carcinoma cells. Artemin is therefore oncogenic for human mammary carcinoma, and targeted therapeutic approaches to inhibit artemin function in mammary carcinoma warrant consideration.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos , Camundongos Nus , Invasividade Neoplásica , Transplante de Neoplasias , Transplante Heterólogo
5.
Mikrobiologiia ; 76(3): 340-53, 2007.
Artigo em Russo | MEDLINE | ID: mdl-17633409

RESUMO

Microbiological technology for the enhancement of oil recovery based on the activation of the stratal microflora was tested in the high-temperature horizons of the Kongdian bed (60 degrees C) of the Dagang oil field (China). This biotechnology consists in the pumping of a water-air mixture and nitrogen and phosphorus mineral salts into the oil stratum through injection wells in order to stimulate the activity of the stratal microflora which produce oil-releasing metabolites. Monitoring of the physicochemical, microbiological, and production characteristics of the test site has revealed large changes in the ecosystem as a result of the application of biotechnology. The cell numbers of thermophilic hydrocarbon-oxidizing, fermentative, sulfate-reducing, and methanogenic microorganisms increased 10-10 000-fold. The rates of methanogenesis and sulfate reduction increased in the near-bottom zone of the injection wells and of some production wells. The microbial oil transformation was accompanied by the accumulation of bicarbonate ions, volatile fatty acids, and biosurfactants in the formation waters, as well as of CH4 and CO2 both in the gas phase and in the oil. Microbial metabolites promoted the additional recovery of oil. As a result of the application of biotechnology, the water content in the production liquid from the test site decreased, and the oil content increased. This allowed the recovery of more than 14000 tons of additional oil over 3.5 years.


Assuntos
Bactérias/isolamento & purificação , Microbiologia Ambiental , Monitoramento Ambiental , Methanobacteriales/isolamento & purificação , Petróleo/metabolismo , Petróleo/microbiologia , Bactérias/metabolismo , China , Contagem de Colônia Microbiana , Ecossistema , Fermentação , Calefação , Hidrocarbonetos/metabolismo , Microbiologia Industrial/métodos , Metano/metabolismo , Methanobacteriales/metabolismo , Oxirredução , Petróleo/análise , Sulfatos/metabolismo , Bactérias Redutoras de Enxofre/isolamento & purificação , Água/análise , Água/metabolismo
6.
Artigo em Chinês | MEDLINE | ID: mdl-12572022

RESUMO

OBJECTIVE: To investigate the cytotoxic effect(CTE) on human cervix cancer HeLa cells induced by five strains of pathogenic free-living Acanthamoeba. METHODS: The cytotoxic effect of five isolates of Acanthamoeba on HeLa cells was investigated by light microscopy and MTT method. RESULTS: The photomicrographs of HeLa cells showed a sequence of cardinal morphological features of apoptosis when HeLa cells were exposed to Acanthamoeba in a time-dependent manner at a ratio of 1:1 for 12 h. MTT method showed more than 50% of tumor cells underwent cytolysis following exposure to A. lugdunensis trophozoites, and only 18% of cells treated with A. polyphaga underwent CTE. The CTE produced by A. lugdunensis and A. quina trophozoites was more rapid than the others, beginning as early as 6 h after coincubation and resulting in cytolysis by 72 h. CONCLUSION: These five strains of Acanthamoeba exhibit cytotoxic effects of varying degrees on HeLa cells, inducing apoptosis.


Assuntos
Acanthamoeba/patogenicidade , Apoptose , Animais , Células HeLa/parasitologia , Humanos
7.
Parasitology ; 120 ( Pt 2): 211-24, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10726282

RESUMO

The ABA-1 protein of Ascaris lumbricoides (of humans) and Ascaris suum (of pigs) is abundant in the pseudocoelomic fluid of the parasites and also appears to be released by the tissue-parasitic larvae and the adult stages. The genes encoding the polyprotein precursor of ABA-1 (aba-1) were found to be arranged similarly in the two taxa, comprising tandemly repeating units encoding a large polyprotein which is cleaved to yield polypeptides of approximately 15 kDa which fall into 2 distinct classes, types A and B. The polyprotein possibly comprises only 10 units. The aba-1 gene of A. lumbricoides is polymorphic, and the majority of substitutions observed occur in or near predicted loop regions in the encoded proteins. mRNA for ABA-1 is present in infective larvae within the egg, and in all parasitic stages, but was not detectable in unembryonated eggs. ABA-1 mRNA was confined to the gut of adult parasites, and not in body wall or reproductive tissues. Recombinant protein representing a single A-type unit for the A. lumbricoides aba-1 gene was produced and found to bind retinol (Vitamin A) and a range of fatty acids, including the pharmacologically active lipids lysophosphatidic acid, lysoplatelet activating factor, and there was also evidence of binding to leukotrienes. It failed to bind to any of the anthelmintics screened. Differential Scanning Calorimetry showed that the recombinant protein was highly stable, and unfolded in a single transition at 90.4 degrees C. Analysis of the transition indicated that the protein occurs as a dimer and that the dimer dissociates simultaneously with the unfolding of the monomer units.


Assuntos
Ascaríase/parasitologia , Ascaris lumbricoides/genética , Ascaris suum/genética , Proteínas de Helminto/genética , Alérgenos/química , Alérgenos/genética , Alérgenos/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Anti-Helmínticos/química , Antígenos de Helmintos/química , Antígenos de Helmintos/genética , Antígenos de Helmintos/imunologia , Antígenos de Plantas , Ascaríase/sangue , Ascaris lumbricoides/química , Ascaris lumbricoides/imunologia , Ascaris suum/química , Ascaris suum/imunologia , Sequência de Bases , Varredura Diferencial de Calorimetria , China , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , Regulação da Expressão Gênica , Guatemala , Proteínas de Helminto/química , Proteínas de Helminto/imunologia , Humanos , Ligantes , Dados de Sequência Molecular , Plasmídeos , Polimorfismo Genético/genética , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
8.
Mol Biochem Parasitol ; 105(2): 223-36, 2000 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-10693745

RESUMO

A novel fatty acid binding protein, As-p18, is secreted into both the perivitelline and perienteric fluids of the parasitic nematode, Ascaris suum, and at least eight potential homologues of As-p18 have been identified in the Caenorhabditis elegans genome. The products of the three most closely related homologues are fatty acid binding proteins (LBP-1, LBP-2 and LBP-3) which contain putative secretory signals. Phylogenetic analysis revealed that these secreted fatty acid binding proteins comprise a distinct gene class within the fatty acid binding protein family and are possibly unique to nematodes. To examine the potential sites of As-p18 secretion, the expression of the putative promoters of the C. elegans homologues was examined with GFP reporter constructs. The developmental expression of lbp-1 was identical to that of As-p18 and consistent with the secretion of LBP-1 from the hypodermis to the perivitelline fluid. The expression patterns of lbp-2 and lbp-3 were consistent with the secretion of LBP-2 and LBP-3 from muscle into the perienteric fluid later in development. These studies demonstrate that at least some perivitelline fluid proteins appear to be secreted from the hypodermis prior to the formation of the cuticle and, perhaps more importantly, that this coordinate C. elegans/A. suum approach may be potentially useful for examining a number of key physiological processes in parasitic nematodes.


Assuntos
Ascaris suum/metabolismo , Caenorhabditis/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Helminto , Proteína P2 de Mielina/genética , Proteína P2 de Mielina/metabolismo , Proteínas de Neoplasias , Sequência de Aminoácidos , Animais , Ascaris suum/genética , Ascaris suum/crescimento & desenvolvimento , Caenorhabditis/genética , Caenorhabditis/crescimento & desenvolvimento , Proteínas de Transporte/classificação , Proteínas de Transporte/isolamento & purificação , DNA de Helmintos/análise , DNA de Helmintos/genética , Proteínas de Ligação a Ácido Graxo , Regulação da Expressão Gênica no Desenvolvimento , Genes de Helmintos , Dados de Sequência Molecular , Família Multigênica , Proteína P2 de Mielina/classificação , Proteína P2 de Mielina/isolamento & purificação , Filogenia , Alinhamento de Sequência , Análise de Sequência de DNA
9.
J Immunol ; 162(4): 2049-56, 1999 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-9973477

RESUMO

Members of a subfamily of G protein-coupled receptors (GPCRs), encoded by five different endothelial differentiation genes (edgs), specifically mediate effects of lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) on cellular proliferation and differentiation. Mechanisms of suppression of apoptosis by LPA and S1P were studied in the Tsup-1 cultured line of human T lymphoblastoma cells, which express Edg-2 and Edg-4 GPCRs for LPA and Edg-3 and Edg-5 GPCRs for S1P. At 10-10 M to 10-7 M, both LPA and S1P protected Tsup-1 cells from apoptosis induced by Abs to Fas, CD2, and CD3 plus CD28 in combination. Apoptosis elicited by C6 ceramide was inhibited by S1P, but not by LPA, in part because ceramide suppressed expression of Edg-2 and Edg-4 surface receptors for LPA without affecting Edg-3 surface receptors for S1P. At 10-9 M to 10-7 M, LPA and S1P significantly suppressed cellular levels of the apoptosis-promoting protein Bax, without altering the levels of Bcl-xL or Bcl-2 assessed by Western blots and immunoassays. Transfections of pairs of antisense plasmids for Edg-2 plus Edg-4 and Edg-3 plus Edg-5, and hygromycin selection of transfectants with reduced expression of the respective Edg R proteins in Western blots, inhibited both protection from apoptosis and reduction in cellular levels of Bax by LPA and S1P. Thus, LPA and S1P protection from apoptosis is mediated by distinct Edg GPCRs and may involve novel effects on Bax regulatory protein.


Assuntos
Apoptose/imunologia , Proteínas I-kappa B , Imunossupressores/farmacologia , Lisofosfolipídeos/farmacologia , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Receptores Acoplados a Proteínas G , Esfingosina/análogos & derivados , Linfócitos T/imunologia , Animais , Apoptose/efeitos dos fármacos , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Inibidor de NF-kappaB alfa , Proteínas Proto-Oncogênicas/imunologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Antissenso/farmacologia , Receptores de Superfície Celular/antagonistas & inibidores , Receptores de Superfície Celular/biossíntese , Receptores de Superfície Celular/genética , Receptores de Ácidos Lisofosfatídicos , Receptores de Lisofosfolipídeos , Esfingosina/farmacologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Células Tumorais Cultivadas , Proteína Killer-Antagonista Homóloga a bcl-2 , Proteína X Associada a bcl-2 , Proteína de Morte Celular Associada a bcl , Proteína bcl-X
10.
Ann Ist Super Sanita ; 35(4): 489-97, 1999.
Artigo em Italiano | MEDLINE | ID: mdl-10721217

RESUMO

The national trends of the utilisation of non conventional therapies suggest that an increasing number of patients employ remedies that are outside the mainstream of what has been defined as conventional western medicine. The extent to which these practices have clinical efficacy according to biomedical criteria is a matter of ongoing debate. It may be that independent of any such efficacy, the attraction of alternative medicine is related to the power of its underline shared beliefs and cultural assumptions. The fundamental premises are an advocacy of nature, vitalism, "science" and spirituality. For patients, who choose alternative medicine, the most important reason to abandon conventional therapies could be to move from the sterile "high-tech" realm of official medicine to a more intimate "high-touch" intervention offered by non-physicians.


Assuntos
Terapias Complementares/estatística & dados numéricos , Difusão de Inovações , Síndrome da Imunodeficiência Adquirida/terapia , Austrália , Canadá , Europa (Continente) , Soropositividade para HIV/terapia , HIV-1/imunologia , Humanos , Japão , Neoplasias/terapia , Estados Unidos
11.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 15(3): 228-30, 1998 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-12553242

RESUMO

Grafting hydrogels onto silicone rubber membranes were prepared by radiation technique for medical application. This material is characterized by high purity, hydrophilia, formation of stable hydrogel after water absorption, good biocompatibility, etc. Clinical application was initiated on the basis of animal experiments. The material was used in 47 cases of joint and tendon injuries, in 9 cases of rheumatoid arthritis, and in 4 other cases; totaling 60 cases. All patients were followed up for three and a half years after surgical operation. A general effectiveness of above 86% was noted.


Assuntos
Materiais Biocompatíveis/uso terapêutico , Hidrogel de Polietilenoglicol-Dimetacrilato/uso terapêutico , Procedimentos Ortopédicos , Complicações Pós-Operatórias/prevenção & controle , Elastômeros de Silicone/uso terapêutico , Adulto , Idoso , Criança , Feminino , Humanos , Período Intraoperatório , Masculino , Membranas Artificiais , Pessoa de Meia-Idade , Aderências Teciduais/prevenção & controle
12.
J Biol Chem ; 272(15): 9933-41, 1997 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-9092532

RESUMO

Early development of the parasitic nematode, Ascaris suum, occurs inside a highly resistant eggshell, and the developing larva is bathed in perivitelline fluid. Two-dimensional gel analysis of perivitelline fluid from infective larvae reveals seven major proteins; a cDNA encoding one of these, As-p18, has been cloned, sequenced, and protein expressed in Escherichia coli. The predicted amino acid sequence of As-p18 exhibits similarities to the intracellular lipid-binding protein (iLBP) family including retinoid- and fatty acid-binding proteins (FABP). As-p18 is unusual in that it possesses a hydrophobic leader that is not present in the mature protein, the developmental regulation of its expression, and in terms of its predicted structure. Recombinant As-p18 is a functional FABP with a high affinity for both a fluorescent fatty acid analog (11(((5-(dimethylamino)-1-naphthalenyl)sulfonyl)amino) undecanoic acid) and oleic acid, but not retinol. Circular dichroism of rAs-p18 reveals a high beta-sheet content (62%), which is consistent with secondary structure for the protein predicted from sequence algorithms, and the structure of iLBPs. Unusual features are apparent in a structural model of As-p18 generated from existing crystal structures of iLBPs. As-p18 is not found in unembryonated eggs, begins to be synthesized at about day 3 of development, reaches a maximal concentration with the formation of the first-stage larva and remains abundant in the perivitelline fluid of the second-stage larva. Since As-p18 is not present in the post-infective third-stage larva or adult worm tissues, it appears to be exclusive to the egg. Surprisingly, however, Northern blot analysis yields mRNA for As-p18 not only in the early larval stages, but also the unembryonated egg, third-stage larvae, and ovaries of adult worms, even though the protein is not detectable from any of those sources. As-p18 may play a role in sequestering potentially toxic fatty acids and their peroxidation products, or it may be involved in the maintenance of the impermeable lipid layer of the eggshell.


Assuntos
Proteínas de Transporte/metabolismo , Ácidos Graxos/metabolismo , Proteínas de Helminto , Proteína P2 de Mielina/metabolismo , Proteínas de Neoplasias , Proteínas do Tecido Nervoso , Membrana Vitelina/química , Sequência de Aminoácidos , Animais , Ascaris suum , Proteínas de Transporte/química , Proteínas de Transporte/genética , Bovinos , Dicroísmo Circular , Eletroforese em Gel Bidimensional , Proteína 7 de Ligação a Ácidos Graxos , Proteínas de Ligação a Ácido Graxo , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Proteína P2 de Mielina/química , Conformação Proteica , Coelhos , Proteínas Recombinantes/metabolismo , Espectrometria de Fluorescência
13.
EMBO J ; 16(7): 1742-50, 1997 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-9130718

RESUMO

The sid1 and urbs1 genes encode L-ornithine N5-oxygenase and a GATA family transcription regulator, respectively, for siderophore biosynthesis in Ustilago maydis. The basic promoter and iron-regulatory sequences of the U. maydis sid1 gene were defined by fusing restriction and Bal31 nuclease-generated deletion fragments of the promoter region with the Escherichia coli beta-glucuronidase (GUS) reporter gene. Sequences required for basal expression of sid1 mapped within 1043 bp upstream of the translation start site and include the first untranslated exon and first intron. Sequences needed for iron-regulated expression of sid1 were localized to a 306 bp region mapping 2.3 and 2.6 kb upstream of the ATG. The 306 bp region contains two G/TGATAA sequences, consensus DNA binding sites of GATA family transcription factors. Deletion or site-directed mutation of either or both GATA sequences resulted in deregulated expression of sid1. In vitro DNA binding studies showed that Urbs1 binds to the 3'-GATA site in the 306 bp iron-responsive region. However, deletion of 1.1 kb between the distal GATA sites and the basal promoter region led to deregulated expression of GUS, indicating that these GATA sequences are by themselves insufficient to regulate sid1. In vitro DNA binding and in vivo reporter gene analysis revealed that siderophores are not co-repressors of Urbs1.


Assuntos
Proteínas Fúngicas , Oxigenases de Função Mista/biossíntese , Oxigenases de Função Mista/genética , Sideróforos/metabolismo , Fatores de Transcrição/biossíntese , Fatores de Transcrição/metabolismo , Ustilago/enzimologia , Ustilago/genética , Sequência de Bases , Sítios de Ligação , Clonagem Molecular , Primers do DNA , Genes Fúngicos , Genes Reporter , Genótipo , Glucuronidase/biossíntese , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Reação em Cadeia da Polimerase , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/metabolismo , Sitios de Sequências Rotuladas , Fatores de Transcrição/genética , Ustilago/efeitos dos fármacos
14.
Se Pu ; 15(2): 173-5, 1997 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-15739416

RESUMO

Short chain carboxylic acids are the major aqueous organic species in oil field water. It is considered that they play an important role in the geochemical evolution of second porosity in oil reservoir. In this paper, short chain carboxylic acid anions were analyzed by HP(3D)CE high performance capillary electrophoresis system (Hewlett-Packard, Germany) with a buffer system of dinitrobenzoic acid-hexadecyltrimethyl ammonium bromide (CTAB). The influence of buffer pH and the concentrations of electrolyte, surfactant and methanol on the seperation of short chain carboxylic acids have been studied. The results showed that the best separation of short chain carboxylic acids could be done with the buffer of 10mmol/L dinitrobenzoic acid, 0.5mmol/L CTAB and 5% methanol at pH=9. Separations were performed in a 50cm x 50microm i.d. fused silica capillary (effective length 48.5cm) at 25 degrees C. A negative potential of 30kV was used for each experiment. Sample was introduced into the capillary by pressure at 50kPa for 10s. Indirect UV detection was operated at 254nm and reference wavelength at 380nm for all experiments. Negative peak was changed into positive one by exchanging between detection wavelength and reference wavelength. Capillary was rinsed for 10min with 0.1mol/L sodium hydroxide and buffer solution before each run. Oil field water was injected directly after filtered through 0.45microm membrane. The result was satisfactory.


Assuntos
Ácidos Carboxílicos/química , Eletroforese Capilar/métodos , Óleos Combustíveis/análise , Água/análise , Soluções Tampão , Eletroforese Capilar/instrumentação , Espectrofotometria Ultravioleta
15.
Proc Natl Acad Sci U S A ; 90(3): 903-7, 1993 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8430103

RESUMO

Iron uptake in Ustilago maydis is mediated by production of extracellular hydroxamate siderophores. L-Or-nithine N5-oxygenase catalyzes hydroxylation of L-ornithine, which is the first committed step of ferrichrome and ferrichrome A biosynthesis in U. maydis. We have characterized sid1, a gene coding for this enzyme, by complementation in trans, gene disruption, and DNA sequence analysis. A comparison of genomic DNA and cDNA sequences has shown that the gene is interrupted by three introns. The putative amino acid sequence revealed similarity with Escherichia coli lysine N6-hydroxylase, which catalyzes the hydroxylation of lysine, the first step in biosynthesis of aerobactin. Two transcription initiation points have been determined, both by PCR amplification of the 5' end of the mRNA and by primer extension. A 2.3-kb transcript which accumulates in cells grown under low iron conditions was detected by Northern hybridization. A less abundant 2.7-kb transcript was observed in cells grown in iron-containing medium. By contrast, constitutive accumulation of the 2.3-kb transcript was observed in a mutant carrying a disruption of urbs1, a gene involved in regulation of siderophore biosynthesis. Analysis of the pathogenicity of mutants carrying a null allele of sid1 suggests that the biosynthetic pathway of siderophores does not play an essential role in the infection of maize by U. maydis.


Assuntos
Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Genes Fúngicos/genética , Ferro/farmacologia , Oxigenases de Função Mista/genética , Sideróforos/biossíntese , Ustilago/genética , Sequência de Aminoácidos , Sequência de Bases , Mapeamento Cromossômico , Clonagem Molecular , Oxigenases de Função Mista/efeitos dos fármacos , Dados de Sequência Molecular , Mutagênese Insercional , RNA Mensageiro/genética , Homologia de Sequência de Aminoácidos , Ustilago/efeitos dos fármacos , Ustilago/enzimologia , Ustilago/patogenicidade , Virulência , Zea mays/microbiologia
16.
J Biol Chem ; 264(28): 16613-9, 1989 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-2674138

RESUMO

A family of four glutamine amidotransferases has a homologous glutamine amide transfer domain, designated purF-type, that is named after purF-encoded glutamine phosphoribosylpyrophosphate amidotransferase. The glutamine amide transfer domain of approximately 194 amino acid residues is at the NH2 terminus of the protein chain. Site-directed mutagenesis was used to replace several of the 9 invariant amino acids in the glutamine amide transfer domain of glutamine phosphoribosylpyrophosphate amidotransferase. The results indicate that a Cys1-His101-Asp29 catalytic triad is involved in the glutamine amide transfer function of this enzyme. The evidence suggests that His101 functions to increase the nucleophilicity of Cys1, which is used to form a glutamine-enzyme covalent intermediate. Asp29 has a role subsequent to formation of the covalent intermediate. The Cys-His-Asp catalytic triad is implicated in the glutamine amide transfer function of purF-type amidotransferases.


Assuntos
Antranilato Sintase , Transferases de Grupos Nitrogenados , Transferases/genética , Sequência de Aminoácidos , Ácido Aspártico , Sítios de Ligação , Cisteína , Escherichia coli/enzimologia , Escherichia coli/genética , Histidina , Dados de Sequência Molecular , Mutação , Transferases/metabolismo
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