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2.
Water Sci Technol ; 66(10): 2083-9, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22949237

RESUMO

The main aquifer of the Llobregat delta (Barcelona, Spain) has been affected by seawater intrusion since the 1960s. The Catalan Water Agency (ACA) has sponsored the construction of a positive hydraulic barrier in order to stop the progress of seawater intrusion advance due to the intensive aquifer development. The hydraulic barrier consists of 15 wells into which highly treated reclaimed water from the waste water treatment plant of the Baix Llobregat is injected. Water is subjected, prior to the distribution to the injection wells, to secondary and tertiary treatments, and later to ultrafiltration, UV disinfection without chlorination, and salinity reduction through reverse osmosis. A preliminary pilot phase of the project was started in late 2007, with highly positive results, and the second phase started in mid 2010. Hydrogeological and hydrochemical monitoring data indicate an efficient performance and aquifer improvement. The evaluation of such efficiency and operational costs has been analyzed and discussed.


Assuntos
Água Subterrânea , Reciclagem , Água do Mar , Eliminação de Resíduos Líquidos , Desinfecção , Monitoramento Ambiental/métodos , Reciclagem/economia , Espanha , Fatores de Tempo , Ultrafiltração , Raios Ultravioleta , Poluentes Químicos da Água , Poluição Química da Água , Purificação da Água
3.
Theriogenology ; 154: 59-65, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32480065

RESUMO

This study aimed to evaluate the effect of sodium caseinate added into freezing extender on the sperm parameters of cryopreserved bull semen and in vitro and in vivo fertility. One ejaculate of 30 bulls was used and processed using Botu-Bov (Botupharma, Botucatu, Brazil) with the addition of 20% egg yolk (EY) or 15% egg yolk with 2% sodium caseinate (EY + SC), subsequently submitted to freezing. Semen from both groups were evaluated immediately after thawing (T0) and after thermic stress at 37 °C for 90 min (T90), for sperm kinetics, by CASA method, and plasma membrane integrity (PMI), superoxide (O2-) concentration and high mitochondrial potential (HMP) by flow cytometry. In vitro fertilization (IVF) was performed to assess embryo cleavage rate on day 3, and blastocyst rate on day 8. The in vivo fertility test was performed using fixed-time artificial insemination (FTAI). In sperm evaluation, trajectory velocity, linear velocity, curvilinear velocity, and lateral head movement were higher (P < 0.05) in EY + SC at T0. At T90, while rectilinearity and linearity did not differ between EY and EY + SC (P > 0.05), the other parameters evaluated were higher in EY + SC. Similarly, the integrity of the plasma and acrosomal membranes (iPAM) was higher (P < 0.05) at T90 in EY + SC, but did not differ (P > 0.05) between the groups at T0. For O2- and HMP, the values were lower (P < 0.05) in EY + SC group in both moments; furthermore, EY + SC showed higher cleavage and blastocyst rates in IVF. Likewise, pregnancy rates by FTAI were higher (P < 0.05) in the EY + SC group. In conclusion, the addition of sodium caseinate into freezing extender improves sperm parameters of frozen-thawed bull semen and fertility rates on during in vitro and in vivo tests.


Assuntos
Preservação do Sêmen , Sêmen , Animais , Brasil , Caseínas , Bovinos , Criopreservação/veterinária , Crioprotetores , Feminino , Fertilidade , Longevidade , Masculino , Gravidez , Preservação do Sêmen/veterinária , Motilidade dos Espermatozoides , Espermatozoides
4.
Circ Res ; 87(6): 508-15, 2000 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-10988244

RESUMO

Extracellular matrix (ECM) regulates vascular smooth muscle cell proliferation. The role of ECM in myocardial growth is unexplored. We sought to determine whether human fetal ventricular myocytes (HFVMs) produce ECM and whether synthesis and attachment to ECM are necessary for their epidermal growth factor (EGF)-dependent and -independent proliferation. Cultured HFVMs proliferate in the presence but not absence of serum and EGF, as determined by increase in cell number and [(3)H]thymidine and [(14)C]leucine incorporation (measures of DNA and protein synthesis, respectively). Using a cyanogen bromide digestion technique to measure collagen and elastin and using affinity chromatography for fibronectin, we found that HFVMs synthesized collagen and fibronectin but not elastin. HFVMs grown on exogenous ECM (including fibronectin and type I collagen and laminin) demonstrated no change in proliferation or DNA and protein synthesis with or without EGF. However, inhibition of collagen synthesis using cis-4-hydroxyproline resulted in a decrease in EGF-related HFVM proliferation and DNA and protein synthesis, which was reversed by exposure to L-proline but not by growth on type I collagen. Use of beta(1) but not beta(3) integrin antibody to inhibit cell interaction with ECM resulted in a decrease in HFVM proliferation and DNA and protein synthesis in response to EGF. Furthermore, EGF-dependent proliferation was enhanced by alpha(1)beta(1) and alpha(5)beta(1) antibodies that act as functional ligands, but not alpha(3)beta(1), the only beta(1) subtype expressed in adult myocytes. In conclusion, proliferating HFVMs synthesize collagen and fibronectin. The proliferative response of HFVMs to EGF requires the synthesis of collagen as well as attachment to specific alpha/beta(1) integrin heterodimers.


Assuntos
Matriz Extracelular/metabolismo , Integrinas/fisiologia , Miocárdio/citologia , Apoptose , Adesão Celular , Contagem de Células , Divisão Celular , Células Cultivadas , Cromatografia de Afinidade , Colágeno/biossíntese , DNA/biossíntese , Elastina/biossíntese , Desenvolvimento Embrionário e Fetal , Fator de Crescimento Epidérmico/fisiologia , Matriz Extracelular/fisiologia , Fibronectinas/biossíntese , Ventrículos do Coração/citologia , Humanos , Imuno-Histoquímica , Leucina/metabolismo , Miocárdio/metabolismo , Testes de Precipitina , Timidina/metabolismo
5.
Carbohydr Polym ; 151: 408-416, 2016 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-27474583

RESUMO

Agar/soy protein biocomposite films were successfully processed by extrusion and compression moulding, obtaining transparent and homogeneous films. The conformational changes occurred during the extrusion process and the effect of agar on the final properties were analyzed. As shown by differential scanning calorimetry (DSC) and specific mechanical energy (SME) values, during the extrusion process protein denatured and unfolded protein chains could interact with agar. These interactions were analyzed by Fourier transform infrared spectroscopy (FTIR) and the secondary structure was determined from the amide I band. Those interactions were supported by the decrease of film solubility. Furthermore, the good compatibility between agar and soy protein was confirmed by the images from scanning electron microscopy (SEM).


Assuntos
Ágar/química , Proteínas de Soja/química , Microscopia Eletrônica de Varredura , Conformação Molecular , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Clin Transl Oncol ; 17(6): 419-30, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25617146

RESUMO

Giant cell tumour of bone (GCTB) is a benign osteolytic tumour with three main cellular components: multinucleated osteoclast-like giant cells, mononuclear spindle-like stromal cells (the main neoplastic components) and mononuclear cells of the monocyte/macrophage lineage. The giant cells overexpress a key mediator in osteoclastogenesis: the RANK receptor, which is stimulated in turn by the cytokine RANKL, which is secreted by the stromal cells. The RANK/RANKL interaction is predominantly responsible for the extensive bone resorption by the tumour. Historically, standard treatment was substantial surgical resection, with or without adjuvant therapy, with recurrence rates of 20-56 %. Studies with denosumab, a monoclonal antibody that specifically binds to RANKL, resulted in dramatic treatment responses, which led to its approval by the United States Food and Drugs Administration (US FDA). Recent advances in the understanding of GCTB pathogenesis are essential to develop new treatments for this locally destructive primary bone tumour.


Assuntos
Neoplasias Ósseas , Tumor de Células Gigantes do Osso , Neoplasias Ósseas/terapia , Tumor de Células Gigantes do Osso/terapia , Humanos
7.
Res Microbiol ; 142(2-3): 253-7, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1925025

RESUMO

Gene products that play a role in the formation of cell septum should be expected to be endowed with a set of specific properties. In principle, septal proteins should be located at the cell envelope. The expression of division genes should ensure the synthesis of septal proteins at levels commensurate with the needs of cell division at different rates of cell duplication. We have results indicating that some fts genes located within the 2.5-min cluster in the Escherichia coli chromosome conform to these predictions.


Assuntos
Escherichia coli/citologia , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Sequência de Bases , Divisão Celular/genética , DNA Bacteriano/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Bacterianos , Óperon , Transcrição Gênica
8.
Regul Pept ; 50(2): 177-84, 1994 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-8190917

RESUMO

Different evidence suggests that VIP has immunoregulatory functions and may be secreted by different cells involved in inflammatory and immune responses. In the present study, we demonstrate by reverse transcription (RT) and polymerase chain reaction (PCR) VIP gene expression in rat thymocytes and T and B cells derived from spleen and lymph nodes. We have obtained a specific VIP cDNA product of 458 bp identical in size to that obtained from cerebral cortex. These results have been confirmed by Southern blot analysis. VIP message has also been detected in the T-T hybridoma YH-1633 and in a non-immune cell line, the pheochromocytoma PC 12. VIP gene expression in central and peripheral lymphoid organs suggests that VIP may be a T and B cell-derived cytokine involved in T-cell differentiation and in cell immune responses.


Assuntos
Linfócitos B/metabolismo , RNA Mensageiro/biossíntese , Linfócitos T/metabolismo , Peptídeo Intestinal Vasoativo/biossíntese , Animais , Sequência de Bases , Southern Blotting , Expressão Gênica/genética , Linfonodos/citologia , Linfonodos/metabolismo , Masculino , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Ratos , Ratos Wistar , Baço/citologia , Baço/metabolismo , Timo/citologia , Timo/metabolismo , Transcrição Gênica , Peptídeo Intestinal Vasoativo/genética
9.
Heart ; 81(6): 661-8, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10336930

RESUMO

OBJECTIVES: To determine the accuracy of prenatal diagnosis of pulmonary atresia and intact ventricular septum (PAIVS), and pulmonary stenosis, including prenatal detection of ventriculocoronary connections, to evaluate heart size during the prenatal period, and to evaluate the outcome. DESIGN AND PATIENTS: Medical records of 20 cases with prenatally diagnosed PAIVS and pulmonary stenosis were reviewed retrospectively. Prenatal and postnatal echocardiography were also reviewed and dimensions of the ventricles and vessels were measured retrespectively. RESULTS: Of 20 prenatal diagnoses (15 PAIVS and five pulmonary stenosis), 16 were confirmed as correct. One critical pulmonary stenosis case had been diagnosed as PAIVS prenatally; three had no confirmation. Eight pregnancies were terminated, three had no active treatment, and nine were treated; all survived. Of 13 assessed with ventriculocoronary connections prenatally, seven were diagnosed correctly (four with, three without ventriculocoronary connections), but one was falsely positive; five had no confirmation. The more prominent hypoplasia of the main pulmonary artery and the tricuspid valve annulus, and the sigmoid shape of the ductus arteriosus, seemed to be associated with the presence of ventriculocoronary connections. CONCLUSIONS: Current prenatal echocardiography can accurately diagnose right ventricular outflow tract obstruction and ventriculocoronary connections. Prenatal detection of this constellation of abnormalities aids in family counselling and decisions on postnatal management.


Assuntos
Doenças Fetais/diagnóstico por imagem , Estenose da Valva Pulmonar/diagnóstico por imagem , Ultrassonografia Pré-Natal , Obstrução do Fluxo Ventricular Externo/diagnóstico por imagem , Anormalidades Múltiplas/diagnóstico por imagem , Ecocardiografia Doppler , Feminino , Doenças Fetais/patologia , Idade Gestacional , Humanos , Recém-Nascido , Miocárdio/patologia , Gravidez , Artéria Pulmonar/patologia , Atresia Pulmonar/diagnóstico por imagem , Estenose da Valva Pulmonar/patologia , Estudos Retrospectivos , Valva Tricúspide/patologia , Obstrução do Fluxo Ventricular Externo/patologia
10.
Cir Pediatr ; 8(1): 2-6, 1995 Jan.
Artigo em Espanhol | MEDLINE | ID: mdl-7766468

RESUMO

Our experience in 12 cases of pediatric patients with scimitar syndrome is reported. Except for one, all of them presented cardiac or respiratory manifestations. The symptomatology was related to associated defects (3 atrial septal defects and 1 multiple peripheric pulmonary stenosis), degree of pulmonary hypoplasia, size of the right to left shunt and pulmonary hypertension. 3 patients underwent surgical treatment. One of them died during operation and the other two have had a good evolution. Nine patients with later respiratory manifestations have improved their condition progressively without surgical intervention. Therapeutic approach for patients with scimitar syndrome, respiratory manifestations and onset beyond the neonatal period, should be conservative.


Assuntos
Síndrome de Cimitarra , Adolescente , Angiografia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Síndrome de Cimitarra/diagnóstico por imagem , Síndrome de Cimitarra/cirurgia
11.
Heart ; 93(1): 100-6, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16807270

RESUMO

OBJECTIVES: To determine the characteristic morphological features of hearts with concordant ventriculoarterial connections and parallel arterial trunks, and to provide unequivocally a method to describe their anatomy. DESIGN, METHODS AND PATIENTS: The entire cardiac database and cardiac pathological archive at the Hospital for Sick Children, Toronto, Ontario, Canada, was interrogated to identify all patients with concordant ventriculoarterial connections and parallel arterial trunks. The clinical records, autopsy reports and actual cardiac specimens of those who underwent autopsy, were reviewed. RESULTS: 8 cases meeting our criteria were identified. The infundibular anatomy was variable, including four hearts with bilateral infundibulums, three with subpulmonary infundibulums and one with bilaterally absent infundibulums. Considerable variability was also found in the type of atrial arrangement, along with the morphology of the atrioventricular junctions. The most common findings were the usual atrial arrangement (n = 5), left juxtaposition of the right atrial appendages (n = 3), an atrial septal defect (n = 6), univentricular atrioventricular connection (n = 5), ventricular septal defect (n = 8) and pulmonary obstruction (n = 4). In addition, five specimens had either a single coronary artery or two coronary arteries arising from the anticipated right coronary aortic sinus. CONCLUSIONS: Concordant ventriculoarterial connections with parallel arterial trunks can be found in a variety of segmental combinations. An accurate diagnosis of these rare hearts can be achieved by detailed analysis of not only the ventriculoarterial connections but also the infundibular anatomy and the spatial relationship of the arterial trunks. Particular attention to the coronary arteries is warranted.


Assuntos
Transposição dos Grandes Vasos/patologia , Aorta/patologia , Anomalias dos Vasos Coronários/patologia , Evolução Fatal , Feminino , Átrios do Coração/anormalidades , Átrios do Coração/patologia , Ventrículos do Coração/anormalidades , Ventrículos do Coração/patologia , Humanos , Lactente , Recém-Nascido
12.
Endoscopy ; 38(12): 1246-9, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17163327

RESUMO

BACKGROUND AND STUDY AIMS: Patients undergoing pancreaticoduodenectomy develop postoperative complications related to surgery and their disease. Very little data are available on the role or success of endoscopic retrograde cholangiopancreatography (ERCP) in such patients. The aim of this study was to evaluate the indications and role of diagnostic and therapeutic ERCP after pancreaticoduodenectomy for both benign and malignant disease. PATIENTS AND METHODS: This study was a 10-year (1990 - 2000) single institution retrospective review of all ERCPs performed on patients who had undergone pancreaticoduodenectomy surgery. Indications for the ERCP and technical procedural success were studied. RESULTS: 29 patients with a pancreaticoduodenectomy underwent 56 ERCPs. Reasons for surgery were neoplasia and chronic pancreatitis. Indications for ERCP included evaluation of jaundice and pain. Technical success related to the clinical indication (jaundice 69 %, pain 54 %). CONCLUSION: ERCP plays an important role in the management of postpancreatic surgery problems including biliary and anastomotic strictures, and should be the modality of choice. However, surgical technique may make the afferent limb inaccessible, and the ductal anastomosis difficult to identify in patients with some types of pancreaticoduodenectomy. Closer collaboration between surgeon and endoscopist may allow alterations in surgical technique to improve postoperative ERCP success.


Assuntos
Colangiopancreatografia Retrógrada Endoscópica/métodos , Pancreatopatias/diagnóstico , Pancreatopatias/terapia , Pancreaticoduodenectomia/métodos , Oclusão com Balão , Humanos
13.
Rev. chil. obstet. ginecol ; 76(5): 325-333, 2011. ilus
Artigo em Espanhol | LILACS | ID: lil-608802

RESUMO

Antecedentes: La posibilidad de que un recién nacido presente algún tipo de defecto congénito al nacimiento es de un 2-4 por ciento y la aplicación de métodos de cribado de cromosomopatías y de malformaciones estructurales puede reducir la prevalencia de estos defectos congénitos al nacimiento. Objetivos: Demostrar que es posible la implantación de un cribado de malformaciones congénitas de garantía (sensibilidad de diagnóstico para malformaciones estructurales mayores y para síndrome de Down del 80 por ciento) y universal (aplicado al 90 por ciento de gestantes). Proponemos que la implantación de este cribado supone una disminución de la tasa de los defectos congénitos no diagnosticados al nacimiento a menos del 0,5 por ciento de los recién nacidos. Método: Estudio prospectivo. Hemos valorado 12.478 gestantes (julio 2006-septiembre de 2009). Método de cribado de defecto congénitos: test combinado asociado a ecografía morfológica (18-22 semanas) Resultados: La prevalencia de defecto congénito fue de 2,26 por ciento [IC 95 por ciento: 1,9-2,5] (282/12478). Valoración ecográfica fue del 99,2 por ciento de las gestantes. Tasa de diagnóstico de malformaciones estructurales fue de 79,3 por ciento [IC 95 por ciento: 74,3-84,4] (196/247) y 95,6 por ciento [IC 95 por ciento: 91,8-99,3] (110/115) para las malformaciones mayores. Se ofertó un cribado de cromosomopatias al 95,1 por ciento de las gestantes con una tasa de diagnóstico del 88,5 por ciento [IC 95 por ciento: 79,9-99] (31/35). Conclusiones: Un cribado de defectos congénitos universal y de garantías logró disminuir la prevalencia de defectos congénitos al nacimiento sin diagnosticar a un 0,5 por ciento.


Background: The probability of a newborn presenting some kind of congenital defect at birth is 2-4 percent and the application of methods of screening for chromosomal and structural abnormalities can reduce the prevalence of these defects at birth. Objectives: The aim of this study is to prove that it is possible to implement a screening for congenital malformations that is standardised (diagnostic sensitivity [Sen]>80 percent for major structural deformations and Down's syndrome) and universal (90 percent of pregnant women). We also want to prove that this screening reduces the rate of undiagnosed congenital defects at birth. Methods: Prospective study. We assessed 12,478 pregnant women (July 2006- September 2009). A morphological ultrasound (18-22 weeks) and a combined test were carried out as the methods for screening for congenital defects. Results: The prevalence of congenital defects was 2.26 percent [95 percent CI: 1.9-2.5] (282/12478). The ultrasound scan was performed on 99.2 percent of the pregnant women. There was a Sen of 79.3 percent [95 percent CI: 74.3-84.4] (196/247) for structural malformation and 95.6 percent [95 percent CI: 91.8-99.3] (110/115) for major malformations). Screening for chromosomal anomalies was performed on 95.1 percent of pregnant women with a Sen of 88.5 percent [95 percent CI: 79.9-99] (31/35). Conclusions: A standardised and universal screening for congenital defects reduced the prevalence of undiagnosed congenital defects at birth to 0.5 percent.


Assuntos
Humanos , Adolescente , Adulto , Feminino , Gravidez , Pessoa de Meia-Idade , Anormalidades Congênitas/diagnóstico , Diagnóstico Pré-Natal/métodos , Programas de Rastreamento , Anormalidades Congênitas/epidemiologia , Aberrações Cromossômicas , Reações Falso-Positivas , Biomarcadores , Estudos Prospectivos , Sensibilidade e Especificidade , Espanha , Síndrome de Down/diagnóstico , Ultrassonografia Pré-Natal
14.
World J Microbiol Biotechnol ; 9(4): 414-20, 1993 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24420108

RESUMO

Regulation of gene expression in prokaryotic cells usually takes place at the level of transcription initiation. Different forms of RNA polymerase recognizing specific promoters are engaged in the control of many prokaryotic regulons. This also seems to be the case for some Escherichia coli genes that are induced at low growth rates and by nutrient starvation. Their gene products are synthesized at levels inversely proportional to growth rate, and this mode of regulation has been termed gearbox gene expression. This kind of growth-rate modulation is exerted by specific transcriptional initiation signals, the gearbox promoters, and some of them depend on a putative new σ factor (RpoS). Gearbox promoters drive expression of morphogenetic and cell division genes at constant levels per cell and cycle to meet the demands of cell division and septum formation. A mechanism is proposed that could sense the growth rate of the cell to alter gene expression by the action of specific σ factors.

15.
Mol Microbiol ; 24(5): 927-36, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9220001

RESUMO

The essential cell-division gene ftsZ is transcribed in Escherichia coli from at least six promoters found within the coding regions of the upstream ddlB, ftsQ, and ftsA genes. The contribution of each one to the final yield of ftsZ transcription has been estimated using transcriptional lacZ fusions. The most proximal promoter, ftsZ2p, contributes less than 5% of the total transcription from the region that reaches ftsZ. The ftsZ4p and ftsZ3p promoters, both located inside ftsA, produce almost 37% of the transcription. An ftsAp promoter within the ftsQ gene yields nearly 12% of total transcription from the region. A large proportion of transcription (approximately 46%) derives from promoters ftsQ2p and ftsQ1p, which are located inside the upstream ddlB gene. Thus, the ftsQAZ genes are to a large extent transcribed as a polycistronic mRNA. However, we find that the ftsZ proximal region is necessary for full expression, which is in agreement with a recent report that mRNA cleavage by RNase E at the end of the ftsA cistron has a significant role in the contol of ftsZ expression.


Assuntos
Proteínas de Bactérias/genética , Proteínas do Citoesqueleto , Proteínas de Escherichia coli , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Transcrição Gênica , Divisão Celular , Clonagem Molecular , Óperon Lac , Proteínas de Membrana/genética , Família Multigênica
16.
Mol Microbiol ; 5(9): 2085-91, 1991 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1766382

RESUMO

Regulation of transcription occurs at different levels, one being in the presence of sequences specifically recognized by different forms of RNA polymerase, i.e. the promoters. Three different kinds of promoter are defined according, among other things, to their dependence on the growth rate of the cell: the 'house-keeper' promoter of many metabolic genes, the stringent promoter found at several rRNA and ribosomal protein genes, and the 'gearbox' at genes whose products are required at higher relative amounts at lower growth rates. The identified gearbox promoters of Escherichia coli share specific homologies in the -10, -35 and upstream regions. Although there may be different types of gearbox promoters, the -10 sequence of one of these promoters has been found to be essential for functioning as a gearbox. This suggests the existence of specific sigma factors for its transcription. RpoS (KatF) is a likely candidate for being one of these sigma factors. Computer simulation allows us to predict that such sigma factors should, in turn, be expressed following a gearbox mode, which would then imply the existence of self-regulated loops contributing to the expression of some genes of bacterial division.


Assuntos
Divisão Celular/genética , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas/genética , Transcrição Gênica/genética , Sequência de Bases , Proteínas de Ligação a DNA , Dados de Sequência Molecular , Homologia de Sequência do Ácido Nucleico
17.
EMBO J ; 9(11): 3787-94, 1990 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1698623

RESUMO

The cell division ftsQAZ cluster and the ftsZ-dependent bolA morphogene of Escherichia coli are found to be driven by gearboxes, a distinct class of promoters characterized by showing an activity that is inversely dependent on growth rate. These promoters contain specific sequences upstream from the mRNA start point, and their -10 region is essential for the inverse growth rate dependence. Gearbox promoters are essential for driving ftsQAZ and bolA gene expression so that the encoded products are synthesized at constant amounts per cell independently of cell size. This mode of regulation would be expected for the expression of proteins that either play a regulatory role in cell division or form a stoichiometric component of the septum, a structure that, independently of cell size and growth rate, is produced once per cell cycle.


Assuntos
Escherichia coli/genética , Genes Bacterianos , Regiões Promotoras Genéticas , Sequência de Bases , Análise Mutacional de DNA , Escherichia coli/crescimento & desenvolvimento , Dados de Sequência Molecular , RNA Bacteriano/genética , RNA Mensageiro/genética , Sequências Reguladoras de Ácido Nucleico , Regiões Terminadoras Genéticas , Transcrição Gênica
18.
EMBO J ; 12(10): 3957-65, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8404863

RESUMO

The FtsZ protein is a key element controlling cell division in Escherichia coli. A powerful transcription titration assay was used to quantify the ftsZ mRNA present in synchronously dividing cells. The ftsZ mRNA levels oscillate during the cell cycle reaching a maximum at about the time DNA replication initiates. This cell cycle dependency is specifically due to the two proximal ftsZ promoters. A strain was constructed in which expression of ftsZ could be modulated by an exogenous inducer. In this strain cell size and cell division frequency were sensitive to the cellular FtsZ contents, demonstrating the rate-limiting role of this protein in cell division. Transcriptional activity of the ftsZ promoters was found to be independent of DnaA, indicating that DNA replication and cell division may be independently controlled at the time when new rounds of DNA replication are initiated. This suggests a parallelism between the prokaryotic cell cycle signals and the START point of eukaryotic cell cycles.


Assuntos
Proteínas de Bactérias/genética , Proteínas do Citoesqueleto , Escherichia coli/genética , Transcrição Gênica , Proteínas de Bactérias/metabolismo , Sequência de Bases , Ciclo Celular , Replicação do DNA , DNA Bacteriano/biossíntese , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/crescimento & desenvolvimento , Meia-Vida , Dados de Sequência Molecular , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo
19.
Br J Cancer ; 71(4): 770-5, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7536021

RESUMO

We have developed a modified chemotaxis chamber assay in which bovine aortic endothelial (BAE) cells degrade Matrigel basement membrane and migrate and form capillary-like structures on type I collagen. This capillary formation occurs in the presence of conditioned media from highly metastatic tumour cell lines, such as B16F10 murine melanoma or MDA-MD-231 human breast adenocarcinoma, but not in the presence of conditioned medium (CM) from the less invasive B16F0 cell line. Replacement of tumour cell CM by 10 ng ml-1 basic fibroblast growth factor (bFGF) also results in capillary-like structure formation by BAE cells. An anti-bFGF antibody blocks this effect, showing that bFGF is one of the factors responsible for the angiogenic response induced by B16F10 CM in our assay. Addition of an anti-laminin antibody reduces significantly the formation of capillary-like structures, probably by blocking the attachment of BAE cells to laminin present in Matrigel. The anti-angiogenic compound suramin inhibits in a dose-dependent manner (complete inhibition with 100 microM suramin) the migration and differentiation of BAE cells on type I collagen in response to B16F10 CM. This assay represents a new model system to study tumour-induced angiogenesis in vitro.


Assuntos
Adenocarcinoma/fisiopatologia , Neoplasias da Mama/fisiopatologia , Capilares/citologia , Diferenciação Celular , Quimiotaxia , Endotélio Vascular/citologia , Melanoma Experimental/fisiopatologia , Neovascularização Patológica , Adenocarcinoma/patologia , Animais , Anticorpos/farmacologia , Aorta , Neoplasias da Mama/patologia , Bovinos , Células Cultivadas , Meios de Cultivo Condicionados , Fator 2 de Crescimento de Fibroblastos/farmacologia , Humanos , Laminina/imunologia , Laminina/farmacologia , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos , Invasividade Neoplásica , Suramina/farmacologia , Células Tumorais Cultivadas
20.
Cell Growth Differ ; 7(3): 373-82, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8838867

RESUMO

The v-erbA oncogene coding for a mutated form of the thyroid hormone (T3) receptor (TR alpha 1) increased the invasion capacity of the mouse B3.1 glial cell line. This effect was mediated by the induction of platelet-derived growth factor (c-sis/PDGF B), as shown by its inhibition using an anti-PDGF BB antibody. Also, the low invasion capacity of parental B3.1 and c-erbA-expressing cells (B3.1 + TR alpha 1) was enhanced by exogenously added PDGF BB. This effect was independent of the growth-promoting activity of PDGF and unrelated to the secretion of metalloproteinases. All three cell types (parental B3.1, B3.1 + v-erbA, and B3.1 + TR alpha 1) secreted similar high levels of the M(r) 72,000 collagenase IV (A) independently of PDGF. Anchorage-independent cell growth was also enhanced by v-erbA; B3.1 + v-erbA cells but neither parental B3.1 nor B3.1 + TR alpha 1 cells formed foci in soft agar. The effect of v-erbA only happened in the presence of serum, suggesting that some serum factor(s) cooperate with PDGF to overcome the anchorage dependence of B3.1 + v-erbA cells. Supporting this, high doses of exogenous PDGF were much less efficient than serum, and the addition of an anti-PDGF BB antibody blocked only partially the effect of serum. Basic fibroblast growth factor was found to cooperate with PDGF to abolish anchorage dependence. Moreover, B3.1 + v-erbA cells detached and grew in suspension when cultured on plastic dishes. Interestingly, the transformation-competent c-jun and fra-1 oncogenes were induced by v-erbA in serum-free medium and are candidates to mediate v-erbA effects. In summary, our results show that v-erbA induces transformation parameters in the glial B3.1 cell line via an increase in c-sis/PDGF B and probably other mechanisms, suggesting a role for (autocrine) PDGF stimulation in glial cell transformation.


Assuntos
Transformação Celular Neoplásica , Genes erbA/fisiologia , Neuroglia/citologia , Fator de Crescimento Derivado de Plaquetas/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Animais , Becaplermina , Sangue , Adesão Celular , Contagem de Células , Divisão Celular , Linhagem Celular , Colagenases/biossíntese , Fator 2 de Crescimento de Fibroblastos/farmacologia , Genes jun/genética , Camundongos , Invasividade Neoplásica , Neuroglia/patologia , Fator de Crescimento Derivado de Plaquetas/farmacologia , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-sis , RNA Mensageiro/análise , Receptores dos Hormônios Tireóideos/genética , Tri-Iodotironina
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