Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 413
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Acta Endocrinol (Buchar) ; 16(3): 362-365, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33363661

RESUMO

Cushing syndrome in the paediatric age group is very difficult to diagnose due to atypical presenting features in children. Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of ACTH-independent Cushing syndrome in children and it has characteristic gross and microscopic pathologic features. We report a case of PPNAD in a 16-year-old boy who was evaluated in our hospital with chief complaints of poor height velocity and rapid weight gain for 2-3 years before presentation. Proper evaluation showed ACTH-independent Cushing syndrome with normal imaging. Total bilateral adrenalectomy was performed followed by hormones replacement. 6 months after surgery, significant acceleration of height velocity was noticed. Patient also lost body weight and developed secondary sexual characteristics.

2.
Anim Biotechnol ; 26(1): 65-72, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25153458

RESUMO

The removal of crossbred bulls from semen collection programs due to the production of poor quality semen causes substantial monetary losses to the dairy industry. Seminal quality, a quantitative trait, is greatly influenced by genome level variations. Deletion and/or duplication of Y chromosomal genes and subsequent changes in gene copy number have a major role in determining spermatogenic efficiency and, therefore, seminal quality. In this study, copy numbers of three Y chromosomal genes TSPY, DDX3Y, and USP9Y in genomic DNA were estimated and compared in two groups of crossbred (Bos taurus × Bos indicus) bulls of ten each, superior and inferior quality semen producing bulls, which were classified based on their seminal quality parameters. For TSPY gene, the inferior quality semen donor group has significantly lower copy number than superior quality semen donor group (p < 0.05). No significant difference was found in DDX3Y and USP9Y gene copy numbers between two groups (p > 0.05). In conclusion, this study demonstrates that the copy number of TSPY, a Y chromosomal spermatogenesis related gene, may be an important determinant to predict the quality of bull semen, facilitating better selection of bulls in a herd for semen collection program.


Assuntos
Bovinos/genética , Dosagem de Genes , Sêmen/fisiologia , Cromossomo Y , Animais , Proteínas de Ciclo Celular/genética , RNA Helicases DEAD-box/genética , Hibridização Genética , Masculino , Ubiquitina Tiolesterase/genética
3.
J Neurooncol ; 117(2): 243-51, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24554053

RESUMO

DNA methylation plays an important role in cancer biology and methylation events are important prognostic and predictive markers in many tumor types. We have used methylation-specific multiplex ligation-dependent probe amplification to survey the methylation status of MGMT and 25 tumor suppressor genes in 73 glioblastoma cases. The data obtained was correlated with overall survival and response to treatment. The study revealed that methylation of promoter regions in TP73 (seven patients), THBS1 (eight patients) and PYCARD (nine patients) was associated with improved outcome, whereas GATA5 (21 patients) and WT1 (24 patients) promoter methylation were associated with poor outcome. In patients treated with temozolomide and radiation MGMT and PYCARD promoter methylation events remained associated with improved survival whereas GATA5 was associated with a poor outcome. The identification of GATA5 promoter methylation in glioblastoma has not previously been reported. Furthermore, a cumulative methylation score separated patients into survival groups better than any single methylation event. In conclusion, we have identified specific methylation events associated with patient outcome and treatment response in glioblastoma, and these may be of functional and predictive/prognostic significance. This study therefore provides novel candidates and approaches for future prospective validation.


Assuntos
Neoplasias Encefálicas/genética , Metilação de DNA/genética , Genes Supressores de Tumor , Glioblastoma/genética , Glioblastoma/mortalidade , Regiões Promotoras Genéticas , Adulto , Idoso , Neoplasias Encefálicas/mortalidade , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase Multiplex , Regiões Promotoras Genéticas/genética
4.
Br J Neurosurg ; 27(4): 413-8, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23281683

RESUMO

PURPOSE: To know the occurrence and distribution of Pilomyxoid Astrocytomas amongst tumours previously diagnosed histologically as Pilocytic Astrocytoma and to assess the clinical impact of this new entity. METHODS: Retrospective Diagnostic review of all cases histologically diagnosed as WHO Grade I Astrocytoma at a single Neurosurgical unit between 1990 and 2003. RESULTS: Of a total of 91 cases identified, 9 were found to have Pilomyxoid histology. Of these, 8 were children (mean age 3.33 years) and 1 adult. 6 tumours were hypothalamochiasmatic in location. The clinical course of Pilomyxoid tumours was aggressive marked by maturation, multiple recurrences and disease control was rarely achieved with single treatment modality as opposed to typical pilocytics. The overall survival of the pilomyxoid group was not statistically different from the pilocytic tumours. CONCLUSIONS: Encompassing all age-groups and locations, Pilomyxoid Astrocytomas constitute about 10% of all tumours previously diagnosed as Pilocytic Astrocytoma. Nearly two-thirds are hypothalamo-chiasmatic in location. Knowledge of this entity is essential for appropriate aggressive treatment and follow-up.


Assuntos
Astrocitoma/patologia , Neoplasias Hipotalâmicas/patologia , Muco , Neoplasias do Nervo Óptico/patologia , Adolescente , Adulto , Idoso , Astrocitoma/classificação , Astrocitoma/epidemiologia , Astrocitoma/mortalidade , Criança , Pré-Escolar , Feminino , Humanos , Neoplasias Hipotalâmicas/epidemiologia , Neoplasias Hipotalâmicas/mortalidade , Incidência , Lactente , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Neoplasias do Nervo Óptico/epidemiologia , Neoplasias do Nervo Óptico/mortalidade , Estudos Retrospectivos , Adulto Jovem
5.
Clin Neuropathol ; 29(2): 105-8, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20175961

RESUMO

We report an unusual case of a patient with a sphenoid wing meningioma that after a few years of static radiological appearance presented with sudden deterioration following rapid growth of tumor with intratumoral infarct. The patient underwent surgery and malignant melanoma deposits within the meningioma were demonstrated on histopathological examination. She had a history of a malignant melanoma (MM) excised from the left forearm 10 months ago with no evidence of recurrence. Although metastasis to meningioma has been widely reported, this is only the second report where the primary tumor is MM. In addition, to the best of our knowledge, intratumoral hypodensity from metastasis is unusual. The tumor-to-tumor phenomenon is discussed and the literature is reviewed.


Assuntos
Melanoma/secundário , Neoplasias Meníngeas/patologia , Meningioma/patologia , Segunda Neoplasia Primária/patologia , Neoplasias Cutâneas/patologia , Feminino , Humanos , Melanoma/cirurgia , Neoplasias Meníngeas/cirurgia , Meningioma/cirurgia , Pessoa de Meia-Idade , Segunda Neoplasia Primária/cirurgia , Neoplasias Cutâneas/cirurgia , Tomografia Computadorizada por Raios X
6.
Science ; 167(3919): 869-70, 1970 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-4903650

RESUMO

Treatment of mice with L-asparaginase from Escherichia coli resulted in a marked suppression of the immune response, as assessed both cellularly and humorally. Suppression occurred only when the enzyme was injected together with the sheep erythrocytes used as antigen. There was little or no effect when the enzyme was injected before the antigen. Simultaneous injection of asparagine prevented suppression, an indication that the effect of the enzyme was due to depletion of an amino acid probably essential for normal lymphoid cell function during antibody production.


Assuntos
Formação de Anticorpos/efeitos dos fármacos , Asparaginase/farmacologia , Eritrócitos/imunologia , Imunossupressores/farmacologia , Animais , Escherichia coli/enzimologia , Esquemas de Imunização , Injeções , Camundongos , Tamanho do Órgão , Ovinos , Baço/efeitos dos fármacos
7.
Science ; 214(4525): 1133-5, 1981 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-7302584

RESUMO

The persistence of synthetic herbicides such as 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and its release in massive amounts as a herbicide (Agent Orange) have created toxicological problems in many countries. In nature, 2,4,5-T is slowly degraded by cooxidation and is not utilized as a sole source of carbon and energy. The technique of plasmid-assisted molecular breeding has led to the development of bacterial strains capable of totally degrading 2,4,5-T by using it as their sole source of carbon at high concentrations (greater than 1 mg/ml). Spectrophotometry and gas chromatography reveal various intermediates during growth of the culture with 2,4,5-T.


Assuntos
Ácido 2,4,5-Triclorofenoxiacético/metabolismo , Bactérias/genética , Plasmídeos , Bactérias/metabolismo , Biotransformação , Divisão Celular , Cinética , Hibridização de Ácido Nucleico
8.
Science ; 228(4696): 135-42, 1985 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-17779620

RESUMO

The mode of degradation of various halogenated compounds in isolated pure cultures and the disposition of the degradative genes have been studied. In many cases the degradative genes are found to be clustered on plasmids and appear to be under positive control. Genetic selection in vivo and genetic manipulations in vitro have allowed construction of strains having wider biodegradative potentials than their natural counterparts. Molecular cloning of the degradative gene clusters for halogenated compounds in vectors with a broad host range also allows the transfer of such genes to a large number of Gram-negative bacteria. The application of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)-degrading microorganisms has demonstrated the effectiveness of this strain in removing large amounts of 2,4,5-T from contaminated soil within a short period, and such soil has been shown to support the growth of plants normally sensitive to low concentrations of 2,4,5-T. The two major challenges that must be addressed in the near future are the development of appropriate microbial technology for the decontamination of soil containing hazardous halogenated compounds, and the promulgation of appropriate regulations to ensure the safety and well-being of the public during the application of genetically improved strains in an open environment.

9.
J Clin Pathol ; 59(2): 153-5, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16443730

RESUMO

BACKGROUND/AIMS: To evaluate the need for routine histopathological analysis of enucleated/eviscerated eyes and changes in indications for eye removal. METHODS: Retrospective review of all enucleation/evisceration histopathology reports over 20 years. Clinical history was correlated with pathological findings. Two 10 year periods (1984-93, 1994-2003) were compared to detect changes in indications for eye removal. RESULTS: In total, 285 histopathology results were traced from 1984 to 2003; 161 and 124 were evisceration and enucleation specimens, respectively. Glaucoma, malignant melanoma, trauma, and retinal detachment were the most frequent diagnoses 1984-1993. Ocular trauma was the most frequent diagnosis 1994-2003, followed by phthisis bulbi and endophthalmitis. Three cases were diagnosed as metastatic carcinoma; all were suspected preoperatively. A fourth case was a diagnostic surprise: adenocarcinoma found in an eye removed for pain and phthisis. Comparison of two 10 year periods showed a decrease in the number of enucleations/eviscerations, perhaps reflecting a decrease in the number of specimens sent. A preference for eviscerations was evident over the 20 years. CONCLUSION: The number of eyes removed and histologically analysed decreased in the period 1994 to 2003, perhaps because of better treatment options, allowing globe preservation. There was a significant shift in the diagnosis in the two time periods, and a preference for evisceration in both. Only one diagnostic surprise was discovered (0.35%). This study does not support the need to send all globes/contents for histopathological examination. However, because of the one unexpected finding, it is recommended where the examination is incomplete or the history of visual loss is unclear.


Assuntos
Oftalmopatias/cirurgia , Enucleação Ocular/tendências , Evisceração do Olho/tendências , Inglaterra , Oftalmopatias/patologia , Enucleação Ocular/estatística & dados numéricos , Evisceração do Olho/estatística & dados numéricos , Traumatismos Oculares/patologia , Traumatismos Oculares/cirurgia , Neoplasias Oculares/patologia , Neoplasias Oculares/cirurgia , Glaucoma/patologia , Glaucoma/cirurgia , Humanos , Melanoma/patologia , Melanoma/cirurgia , Descolamento Retiniano/patologia , Descolamento Retiniano/cirurgia , Estudos Retrospectivos , Procedimentos Desnecessários
10.
In Vivo ; 20(1): 97-102, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16433035

RESUMO

Thepiperazine chlorcyclizine HCl (CCZ), possessing significant antimetabolic as well as virucidal and virustatic activities against the human immunodeficiency virus (HIV) and other retroviruses, was selected to determine its anticarcinogenic potential The anticancer activity of CCZ was evaluated against procarcinogen n-diethylnitrosamine (NDA)-initiated hepatocarcinogenesis, which was subsequently promoted by phenobarbital (PB) in male Sprague-Dawley rats. The anticancer efficacy of CCZ was monitored by estimating some potential markers of neoplastic and preneoplastic hepatic conditions, e.g., glutathione (GSH), glutathione-S-transferase (GST) and gamma-glutamyl transpeptidase (gammaGTP). CCZ exhibited antineoplastic activity on a long-term therapeutic basis. Furthermore, this drug restricted the exponential increase of the antioxidant markers in the hyperplastic nodule and the surrounding liver tissues in comparison with the carcinogen-controlled rats during the entire period of treatment. A decrease in the number of nodules was observed in the CCZ-treated group.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Piperazinas/uso terapêutico , Animais , Carcinógenos/toxicidade , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/patologia , Dietilnitrosamina/toxicidade , Neoplasias Hepáticas Experimentais/induzido quimicamente , Neoplasias Hepáticas Experimentais/patologia , Masculino , Fenobarbital/toxicidade , Ratos , Ratos Sprague-Dawley
11.
Med J Armed Forces India ; 62(3): 246-51, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27365688

RESUMO

BACKGROUND: Management of vascular injuries poses a challenging problem under warlike conditions. Several authorities recommend limb revascularisation only within first 6-8 hours, as the outcome after delayed revascularisation is poor. METHODS: A retrospective analysis of 61 consecutive patients with vascular injury in a forward hospital over a 25- month period was carried out. RESULTS: Vascular injuries constituted 3.1% of all injuries. The mean injury to treatment delay (lag time) was 11 hours, and 10 patients received treatment after 12 hours. The overall amputation rate was 15%, but only 6.5% for those revascularised within 12 hours and 44% for those undergoing surgery after 12 hours (Chi-square 4.59, p < 0.05). Presence of associated fractures was associated with an adverse outcome (Chi-square 4.24, p < 0.05), as was ligation in comparison to revascularisation (Chi-square 7.86, p < 0.005). Popliteal injuries were associated with a high amputation rate. CONCLUSIONS: Failure to revascularise (ligation of artery), presence of associated fracture, and restoration of circulation beyond 12 hours are associated with a high amputation rate.

12.
Trends Microbiol ; 2(5): 151-7, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-8055178

RESUMO

Alginate is an important virulence factor of Pseudomonas aeruginosa, a bacterium that colonizes the pulmonary tracts of cystic fibrosis patients. Alginate is also widely used in the food, pharmaceutical and chemical industries, and consequently there is considerable interest in the molecular biology and biochemistry of alginate synthesis. As well as its therapeutic potential, research on mucoid P. aeruginosa may provide a lead to an alternative source of alginate for industrial use.


Assuntos
Alginatos/metabolismo , Genes Bacterianos/genética , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/genética , Fibrose Cística/microbiologia , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos/fisiologia , Ácido Glucurônico , Ácidos Hexurônicos , Humanos , Modelos Biológicos
13.
In Vivo ; 19(3): 539-45, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15875773

RESUMO

Methyl-L-DOPA, an antihypertensive agent, has significant in vitro activity against a variety of atypical mycobacteria such as the Mycobacterium avium complex, M. scrofulaceum, M. xenopi and M. marinum, and rare pathogens like M. fortuitum. In the present investigation, the screening of the in vitro activity was further extended by testing the in vitro activity against a total of 53 different strains of mycobacteria, including 34 clinical isolates of both drug-sensitive and drug-resistant Mycobacterium tuberculosis. Most of the strains were inhibited at 10-25 microg/mL concentrations of the drug. When methyl-L-DOPA was injected into male mice at a concentration of 10 microg/g body weight (20 g each), methyl-L-DOPA significantly protected them when challenged with a 50 median lethal dose of M. tuberculosis H37Rv102. According to the chi2 test, the in vivo data were highly significant (p<0.01).


Assuntos
Antibacterianos/farmacologia , Anti-Hipertensivos/farmacologia , Levodopa/análogos & derivados , Mycobacterium/efeitos dos fármacos , Animais , Farmacorresistência Bacteriana , Resistência a Múltiplos Medicamentos , Humanos , Levodopa/farmacologia , Masculino , Camundongos , Testes de Sensibilidade Microbiana , Mycobacterium/classificação , Mycobacterium/isolamento & purificação , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose/tratamento farmacológico
14.
Skin Therapy Lett ; 10(1): 1-4, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15776202

RESUMO

The Herpesviridae family (Types 1-8) continues to inflict considerable morbidity and social stigma upon humanity. Once infected with the herpes viruses, especially Types 1-3, they establish permanent residence within our nervous system and reactivate during periods of stress, trauma, and/or other precipitating factors. To date, there is no cure for herpes viral infections but antivirals can attenuate the symptoms and duration of episodic outbreaks. Prophylactic therapy can suppress recurrences. The first antiviral with selective activity against virus-infected cells is considered to be acyclovir. Our article will highlight the clinical indications of the current generation, valacyclovir, which is a prodrug of acyclovir. We consider valacyclovir as a second-generation antiviral, having taken into account the initial selectivity and safety profile of its progenitor, acyclovir.


Assuntos
Aciclovir/análogos & derivados , Aciclovir/uso terapêutico , Antivirais/uso terapêutico , Infecções por Herpesviridae/tratamento farmacológico , Valina/análogos & derivados , Valina/uso terapêutico , Humanos , Pró-Fármacos/uso terapêutico , Valaciclovir
15.
Mol Immunol ; 20(10): 1089-93, 1983 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-6371498

RESUMO

The polysaccharide isolated from Shigella dysenteriae type 2, strain NCTC 566, on Smith degradation and graded hydrolysis yielded three oligosaccharides which were characterised using methylation studies. Using homologous rabbit antiserum and the monosaccharides that constituted the polysaccharide and the oligosaccharides isolated from it and the cross-reactions in some type-specific pneumococcal antisera, immunochemical specificities of different sugar groupings in the polysaccharide molecule were determined. These results indicated that N-acetylglucosamine was the immunodominant sugar in the polysaccharide and the oligosaccharide isolated from the Smith-degraded product and having the structure (formula; see text) gave maximum inhibition of the specific precipitation.


Assuntos
Polissacarídeos Bacterianos/imunologia , Shigella dysenteriae/imunologia , Fenômenos Químicos , Química , Reações Cruzadas , Hidrólise , Soros Imunes/imunologia , Oligossacarídeos/imunologia , Testes de Precipitina
16.
Gene ; 27(2): 173-81, 1984 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-6327465

RESUMO

The genes for the degradation of 3-chlorobenzoic acid ( 3Cba ) are present in a 110-kb plasmid pAC27 . A circular map is established using the restriction endonucleases EcoRI, HindIII and Bg/II. The map is derived from the results obtained by partial restriction digestion, complete single and double restriction digestion and finally confirmed with hybridization of the digested fragments using different purified fragments as probes. The 3Cba degradative genes are found to be clustered in one region of the map (EcoRI fragment A) as judged by molecular cloning with a broad host range vector pLAFRI . A portion of the 3Cba degradative gene cluster appears to undergo ready recombination with the chromosome, even in a recA host, suggesting the probable transposable nature of such gene cluster.


Assuntos
Clorobenzoatos/metabolismo , Plasmídeos , Pseudomonas/genética , Cromossomos Bacterianos/metabolismo , Clonagem Molecular , Enzimas de Restrição do DNA , DNA Bacteriano/análise , Genes Bacterianos , Hibridização de Ácido Nucleico , Pseudomonas/metabolismo , Recombinação Genética
17.
Gene ; 146(1): 1-5, 1994 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-8063091

RESUMO

The algC gene (encoding phosphomannomutase) of Pseudomonas aeruginosa, similarly to the algD gene, is environmentally regulated through transcriptional activation of its promoter. This gene, like algD, has a long (244 bp) 5' untranslated leader region (5' UTR). Using transcriptional and translational algC::lacZ fusions, we show that even though the transcript levels are similar, the beta-galactosidase-specific activities of the translational fusions are much higher than those of the transcriptional fusions during the entire growth phase. Both the 5' UTR and the ribosomal-binding site are shown to be important for efficient translation of the algC mRNA.


Assuntos
Genes Bacterianos , Fosfotransferases (Fosfomutases)/genética , Pseudomonas aeruginosa/genética , Processamento Pós-Transcricional do RNA , Desidrogenases de Carboidrato/genética , Clonagem Molecular , Óperon Lac , Biossíntese de Proteínas , Transcrição Gênica
18.
Gene ; 71(2): 267-77, 1988 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-3224825

RESUMO

A genomic library of total DNA of Pseudomonas cepacia AC1100 was constructed on a broad-host-range cosmid vector pCP13 in Escherichia coli AC80. A 25-kb segment was isolated from the library which complemented a Tn5-generated, 2,4,5-trichlorophenoxyacetic acid-negative (2,4,5-T-) mutant, P. cepacia PT88. This mutation was partially characterized and appeared to be lacking functional enzyme required for metabolism of an intermediate of the 2,4,5-T pathway, recently identified as 5-chloro-1,2,4-trihydroxybenzene [Chapman et al., Abstr. Soc. Environ. Toxicol. Chem. USA 8 (1987) 127]. A simple colorimetric assay was developed to detect the presence of this active enzyme in intact cells and was used to determine the expression of complementing genes. Subcloning experiments showed that a 4-kb BamHI-PstI fragment and a 290-bp PstI-EcoRI fragment, separated by 1.3-kb, were required for complementation. Both fragments are identified to be chromosomal in origin. Hybridization studies using the subcloned fragments revealed that in addition to a Tn5 insertion, mutant PT88 contained an extensive chromosomal deletion accounting for its 2,4,5-T- phenotype. The cloned fragments did not show homology to plasmid DNAs carrying degradative genes for toluene, naphthalene and 3-chlorobenzoate.


Assuntos
Ácido 2,4,5-Triclorofenoxiacético/farmacocinética , Clonagem Molecular , Regulação da Expressão Gênica , Genes Bacterianos , Pseudomonas/genética , Southern Blotting , Deleção Cromossômica , Meios de Cultura , DNA Ligases/metabolismo , Eletroforese em Gel de Ágar , Eletroforese em Gel de Poliacrilamida , Teste de Complementação Genética , Inativação Metabólica , Mutação , Plasmídeos , Mapeamento por Restrição , Homologia de Sequência do Ácido Nucleico , Transformação Bacteriana
19.
Gene ; 112(1): 45-51, 1992 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-1551597

RESUMO

Synthesis of alginate by Pseudomonas aeruginosa correlates with its pathogenicity in the lungs of patients suffering from cystic fibrosis (CF). Alginate synthesis-encoding genes (alg) in P. aeruginosa are normally silent, but are specifically triggered in the CF lung environment. The promoter for the algD gene, located at the upstream end of the alg cluster, is activated by environmental factors such as high osmolarity, nutrient limitation and dehydration. Several regulatory proteins are known to control transcription from the algD promoter. Among these proteins is AlgR1 which is homologous to the phosphorylation-dependent response regulators of the two-component signal transduction system. In this paper, we report that AlgR2, an 18-kDa protein which in cooperation with AlgR1 regulates the algD promoter, undergoes phosphorylation in the presence of ATP. The phosphate group acquired by AlgR2 is then transferred to AlgR1. In addition, we show that AlgR1 can be phosphorylated by an AlgR2-analog in Escherichia coli. AlgR1 is isolated in a phosphorylatable 80-kDa complex in association with AlgR2 in P. aeruginosa and the AlgR2-analog in E. coli.


Assuntos
Alginatos/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/metabolismo , Pseudomonas aeruginosa/metabolismo , Transdução de Sinais/fisiologia , Southern Blotting , Clonagem Molecular , Fibrose Cística/microbiologia , Regulação Bacteriana da Expressão Gênica/fisiologia , Ácido Glucurônico , Ácidos Hexurônicos , Fosforilação , Regiões Promotoras Genéticas/genética , Proteínas Quinases/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , beta-Galactosidase/genética
20.
Gene ; 42(3): 293-302, 1986.
Artigo em Inglês | MEDLINE | ID: mdl-3089876

RESUMO

Phosphomannose isomerase (PMI) has been proposed to catalyze the first step of the alginic acid biosynthetic pathway in Pseudomonas aeruginosa. The nucleotide sequence of the P. aeruginosa pmi gene contained on a 2.0-kb BamHI-SstI DNA fragment has been determined. The gene was defined by the start and stop codons and by in vitro disruption of an open reading frame of 1440 bp corresponding to a polypeptide product with a predicted Mr of 52 860. This polypeptide displayed an apparent Mr of approx. 56 000 upon electrophoresis of a maxicell extract on sodium dodecyl sulfate-polyacrylamide gels. The codon utilization of the pmi gene was distinct in the wobble base preference and influenced by the high G + C content (66 mol%) of the P. aeruginosa DNA. Computer assisted matching analysis failed to demonstrate any significant homology at the nucleotide level between the P. aeruginosa pmi and Escherichia coli manA (pmi) genes. However, sequences homologous to the P. aeruginosa pmi gene were found in other Pseudomonas species, such as P. putida and P. mendocina, and in Azotobacter vinelandii, all capable of producing alginic acid.


Assuntos
Carboidratos Epimerases/genética , Manose-6-Fosfato Isomerase/genética , Pseudomonas aeruginosa/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Códon , Escherichia coli/genética , Genes Bacterianos , Homologia de Sequência do Ácido Nucleico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA