RESUMO
The aim of this study was the evaluation of the safety of anidulafungin in adult solid organ transplantation (SOT) recipients. During the study period (14 months), we included all consecutive SOT recipients from 14 centers who received anidulafungin for at least 48 hours for the treatment of invasive fungal infections (IFIs) or as prophylaxis. Relevant clinical and analytical information on clinical charts was reviewed. Clinical side effects, liver function tests, and serum creatinine levels were assessed at least weekly. The need for the modification of immunosuppressive drugs was also recorded by the investigators. All patients were followed for at least 1 week after the end of treatment (EOT) or until death. Eighty-six SOT recipients were evaluated (56 transplant recipients, 20 lung transplant recipients, 8 kidney transplant recipients, and 2 heart transplant recipients). Sixty-two patients (72%) received anidulafungin for prophylaxis, and 24 (28%) received anidulafungin for the treatment of IFIs [candidemia/invasive candidiasis (16) or invasive aspergillosis (8)]. At the baseline, only 5% of the patients were neutropenic (<500 neutrophils/mL). There was no need for the modification of immunosuppressive drug doses because of anidulafungin therapy. No patient discontinued anidulafungin because of severe adverse effects. While receiving anidulafungin, 1 patient developed mild liver toxicity, but the liver function normalized without the discontinuation of anidulafungin. At EOT, the median serum creatinine, aspartate aminotransferase, and alanine aminotransferase levels were significantly lower than the baseline levels, even in liver transplant recipients and patients who had higher baseline levels of serum creatinine. In conclusion, these results show that anidulafungin is a well-tolerated drug in SOT recipients.
Assuntos
Antifúngicos/administração & dosagem , Equinocandinas/administração & dosagem , Micoses/tratamento farmacológico , Micoses/prevenção & controle , Transplante de Órgãos , Complicações Pós-Operatórias , Adulto , Idoso , Anidulafungina , Antifúngicos/efeitos adversos , Equinocandinas/efeitos adversos , Feminino , Seguimentos , Rejeição de Enxerto/tratamento farmacológico , Transplante de Coração , Humanos , Imunossupressores/uso terapêutico , Transplante de Rim , Transplante de Fígado , Transplante de Pulmão , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/tratamento farmacológico , Complicações Pós-Operatórias/microbiologia , Complicações Pós-Operatórias/prevenção & controle , Estudos Retrospectivos , Adulto JovemRESUMO
OBJECTIVE: To describe the use of extracorporeal membrane oxygenation (ECMO) in refractory respiratory failure. DESIGN: A prospective, observational, multi-center study was carried out. SETTING: Intensive Care Units (ICU) in 148 Spanish hospitals. PATIENTS: Subjects admitted during epidemic weeks 50-52 of 2010 and weeks 1-4 of 2011, receiving respiratory support with ECMO. MAIN VARIABLES OF INTEREST: Clinical and blood gas features, complications and survival of patients with ECMO. RESULTS: Out of 300 ICU admitted patients, 239 (79.6%) were mechanically ventilated. ECMO was available in only 5 ICUs. Nine patients were treated with ECMO (3% of the total and 3.2% of the ventilated patients). In 77.7% of the cases some hypoxemia rescue technique was previously used. ECMO was initiated when ARDS proved refractory to standard treatment. ECMO therapy was started a median of 4.5 days after the onset of mechanical ventilation. The median duration of ECMO was 6 days. Veno-venous (VV) ECMO was the most frequent cannulation mode (88.9%). Four patients had complications associated with ECMO therapy. The median ICU and hospital stay was 17 and 29 days, respectively. In five patients (55.5%), ECMO assistance was satisfactory suspended. The ICU and hospital survival rate was 44.4%. CONCLUSIONS: The use of ECMO in refractory respiratory failure in patients with influenza A (H1N1) is rare in Spain. The hospital survival achieved with its use allows it to be regarded as a possible rescue technique in these patients.
Assuntos
Surtos de Doenças , Oxigenação por Membrana Extracorpórea/estatística & dados numéricos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/complicações , Síndrome do Desconforto Respiratório/terapia , Insuficiência Respiratória/terapia , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/terapia , Adulto , Antivirais/uso terapêutico , Oxigenação por Membrana Extracorpórea/métodos , Feminino , Humanos , Influenza Humana/tratamento farmacológico , Influenza Humana/epidemiologia , Unidades de Terapia Intensiva/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Masculino , Insuficiência de Múltiplos Órgãos/etiologia , Insuficiência de Múltiplos Órgãos/mortalidade , Oseltamivir/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/epidemiologia , Pneumonia Viral/etiologia , Pneumonia Viral/terapia , Estudos Prospectivos , Terapia de Substituição Renal , Respiração Artificial/estatística & dados numéricos , Síndrome do Desconforto Respiratório/epidemiologia , Síndrome do Desconforto Respiratório/etiologia , Insuficiência Respiratória/epidemiologia , Insuficiência Respiratória/etiologia , Estações do Ano , Choque Séptico/etiologia , Choque Séptico/mortalidade , Espanha/epidemiologiaRESUMO
Plants have evolved different mechanisms to increase their tolerance to aluminum (Al) toxicity and low pH in the soil. The Zn finger transcription factor SENSITIVE TO PROTON RHIZOTOXICITY1 (STOP1) plays an essential role in the adaptation of plants to Al and low pH stresses. In this work, we isolated the ScSTOP1 gene from rye (Secale cereale L.), which is located on chromosome 3RS. The ectopic expression of ScSTOP1 complements the Arabidopsis stop1 mutation in terms of root growth inhibition due to Al and pH stress, as well as phosphate starvation tolerance, suggesting that rye ScSTOP1 is a functional ortholog of AtSTOP1. A putative STOP1 binding motif was identified in the promoter of a well-known STOP1 target from rye and Arabidopsis and was later corroborated by genomic DAP-seq analyses. Coexpression analyses verified that ScSTOP1 activated the promoter of ScALMT1. We have also identified a putative phosphorylatable serine in STOP1 that is phylogenetically conserved and critical for such activation. Our data indicated that ScSTOP1 also regulated Al and pH tolerance in rye.
Assuntos
Alumínio/toxicidade , Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Secale/metabolismo , Proteínas de Arabidopsis/genética , Cromossomos de Plantas/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Concentração de Íons de Hidrogênio , Mutação/genética , Transportadores de Ânions Orgânicos/genética , Regiões Promotoras Genéticas/efeitos dos fármacos , Regiões Promotoras Genéticas/genética , Secale/efeitos dos fármacos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
A 1-year-old baby with phylloid-type pigmentary mosaicism, hypotonia, ambiguous genitalia, and a positive screening test for congenital adrenal hyperplasia was referred. Previous sonograph, cytogenetics, and metabolic profile were inconclusive, therefore we performed an additional karyotype and a molecular cytogenetics studies. A mosaic karyotype 45,X/46,X,der(Y)t(Y;14) was characterized in peripheral blood. Congenital adrenal hyperplasia genes were sequenced and the results were negative. The ambiguous genitalia was the result of the special gonosomal mosaicism. The low level of trisomy 14 led to minor physical characteristics and mild mental retardation; also, Turner syndrome features can be expected rather than severe trisomy 14 stigmata.
RESUMO
The AXR1 (auxin-resistant) protein, which has features of the ubiquitin-activating enzyme E1, is required for normal response to the plant hormone auxin in Arabidopsis thaliana. ECR1 functions together with AXR1 to activate members of the RUB/NEDD8 family of ubiquitin-related proteins. Extracts from mutant seedlings lacking AXR1 did not promote formation of the RUB-ECR1 thiolester, indicating that AXR1 is the major activity in this tissue. AXR1 was localized primarily to the nucleus of dividing and elongating cells, suggesting that the targets of RUB modification are nuclear. These results indicate that auxin response depends on RUB modification of one or more nuclear proteins.
Assuntos
Proteínas de Arabidopsis , Arabidopsis/metabolismo , Substâncias de Crescimento , Ácidos Indolacéticos/fisiologia , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Núcleo Celular/metabolismo , Ditiotreitol/farmacologia , Expressão Gênica , Ligases/metabolismo , Dados de Sequência Molecular , Mutação , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas Recombinantes de Fusão/metabolismo , Enzimas Ativadoras de Ubiquitina , Ubiquitina-Proteína Ligases , Ubiquitinas/metabolismoRESUMO
Postoperative Model for End-stage Liver Disease (MELD) values have never been assessed to predict very early (<1 week) death after liver transplantation (OLT). We retrospectively reviewed 275 consecutive OLTs performed in 252 recipients reported in a prospective database. We calculated the MELD score (pre-MELD) and consecutive postoperative MELD (post-MELD) scores computed daily during the first postoperative week and on days 15 and 30 after OLT. Post-MELD scores from nonsurviving recipients displayed on a scatterplot of immediate probability of death were adjusted to the best goodness-of-fit curve, and, finally, depicted graphically as a receiver operating characteristic (ROC) curve. Nonsurviving recipients showed higher post-MELD scores: day 1: 23.5 versus 16.6 (P = .05); day 3: 25.1 versus 12.5 (P = .000); day 5: 25.7 versus 11.8 (P = .000); and day 7: 22.1 versus 10.2 (P = .000). Overall comparisons were performed using a time-dependent general linear regression model, revealing higher post-MELD scores for nonsurviving recipients, irrespective of postoperative time (P = .002). The best goodness-of-fit curve was displayed when adjusting to a theoretical exponential regression curve calculated as follows: Probability of dying within the first week (%) = 3.36 x e(0.079 x (post-MELD)) (r = .89; P = .000). The area under the ROC curve was 0.783 (95% confidence interval, 0.630-0.935; P = .001). The model had a positive predictive value of 82.3%, a negative predictive value of 33.1%, and an accuracy of 79.2%. In conclusion, this study corroborated the suggestion that the MELD score may serve as a reliable tool to assess very early death after OLT.
Assuntos
Falência Hepática/classificação , Falência Hepática/cirurgia , Transplante de Fígado/fisiologia , Adolescente , Adulto , Idoso , Intervalos de Confiança , Bases de Dados Factuais , Feminino , Humanos , Transplante de Fígado/mortalidade , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Valor Preditivo dos Testes , Cuidados Pré-Operatórios , Probabilidade , Curva ROC , Reoperação/estatística & dados numéricos , Estudos Retrospectivos , Taxa de Sobrevida , Sobreviventes , Falha de Tratamento , Resultado do Tratamento , Adulto JovemRESUMO
UNLABELLED: Pruritus is a common complication of cholestatic liver diseases or liver graft dysfunction. Current medical therapies lack efficacy. The molecular adsorbent recirculating system (MARS) represents an interesting therapeutic option. Our objective was to report our experience in the management of four patients with intractable pruritus with MARS. PATIENTS AND METHODS: The MARS treatment cycle included three consecutive treatments, each of 8 hours duration. The four patients with intractable pruritus who were treated had primary biliary cirrhosis/autoimmune hepatitis overlap syndrome (n = 1), ductopenic allograft rejection (n = 2), or posttransplant cholestatic HCV recurrence (n = 1). Intensity of pruritus was documented 24 hours before as well as 24 hours, 7 and 30 days after MARS therapy, and at the end of follow-up. We measured complete blood cell counts, glucose, BUN, creatinine, sodium, potassium, AST, ALT, GGT, alkaline phosphatase, bilirubin, prothrombin activity, and activated partial thromboplastin time. RESULTS: MARS therapy was well tolerated. Patient 1 experienced temporal relief of pruritus, but needed another MARS cycle because of relapse. Patient 2 experienced partial and temporary relief of pruritus, was listed for retransplantation, and received a liver graft 2 months later. Patient 3 showed a dramatic reduction in the degree of pruritus with MARS. Pruritus in patient 4 decreased promptly with MARS therapy and conversion of immunosuppression to tacrolimus, thereby avoiding retransplantation. CONCLUSION: MARS therapy is a promising, safe therapeutic option to treat refractory pruritus caused by cholestatic liver disorders.
Assuntos
Colestase/terapia , Soluções para Hemodiálise , Hepatopatias/cirurgia , Transplante de Fígado/efeitos adversos , Prurido/terapia , Desintoxicação por Sorção , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/terapiaRESUMO
OBJECTIVE: To estimate the cost-effectiveness of three echinocandins (anidulafungin, caspofungin, and micafungin) and generic fluconazole in the treatment of nonneutropenic adult patients with candidemia and/or invasive candidiasis in intensive care units in Spain. MATERIALS AND METHODS: A decision-tree model was applied. The success and safety (hepatic and renal adverse effects) of first-line treatments were obtained from meta-analyses and systematic reviews of clinical trials. In the case of failure, a second-line treatment (liposomal amphotericin B after the echinocandins, or one of the echinocandins after fluconazole) was administered. The duration of the treatments (14 days total) was established by a panel of clinical experts using the Delphi method and according to Infectious Diseases Society of America guidelines. The cost of the medications and renal toxicity were considered. Deterministic and probabilistic sensitivity analysis using Monte Carlo simulations were carried out. RESULTS: The total cost of the treatment of candidemia and/or invasive candidiasis with anidulafungin, caspofungin, micafungin, and fluconazole was 5,483, 5,968, 6,231, and 2,088, respectively. Anidulafungin was the dominant treatment (more effective, less expensive) compared to micafungin and caspofungin. The cost of achieving one more patient successfully treated with anidulafungin, caspofungin, and micafungin compared to fluconazole was 17,199, 23,962, and 27,339, respectively. The result remained stable, despite modification of the duration of the first-line and second-line treatments, as well as most of the dosing regimens. The probabilistic analysis also remained stable. CONCLUSION: In accordance with this economic study, anidulafungin would produce savings and would be the dominant treatment compared with micafungin and caspofungin in nonneutropenic adult patients with candidemia and/or invasive candidiasis in intensive care units in Spain.
RESUMO
BACKGROUND: Current medical knowledge lacks specific information regarding creatine kinase (CK) elevation in influenza A pH1N1 (2009) infection. OBJECTIVES: Primary endpoints were correlation between CK at intensive care unit (ICU) admission and ICU mortality. Secondary endpoints were ICU length of stay (LOS), mechanical ventilation (MV), and requirement of renal replacement techniques (RRT). MATERIALS AND METHODS: A prospective multicenter register included all adults admitted for severe acute respiratory insufficiency (SARI) with confirmed pH1N1 in 148 ICUs. Clinical data including demographics, comorbidities, laboratory information, organ involvement, and prognostic data were registered. Post hoc classification of subjects was determined according to CK level. Data are expressed as median (interquartile range). RESULTS: Five hundred and five (505) patients were evaluable. Global ICU mortality was 17.8 % without documented differences between breakpoints. CK ≥500 UI/L was documented in 23.8 % of ICU admissions, being associated with greater renal dysfunction: acute kidney injury (AKI) was more frequent (26.1 versus 17.1 %, p < 0.05) and twofold requirement of RRT [11 versus 5.6 %, p < 0.05; odds ratio (OR) = 2.09 (95 % confidence interval [CI] 1.01-4.32)]. Increase of CK ≥1,000 UI/L was associated with two or more quadrant involvement on chest X-ray (63.2 versus 40.2 %, p < 0.01) and increased intubation risk (73.9 versus 56.7 %, p = 0.07) and duration of mechanical ventilation (median 15 days versus 11 days, p < 0.01). As a result, CK ≥1,000 UI/L was associated with 5 extra days of ICU and hospital LOS. CONCLUSIONS: CK is a biomarker of severity in pH1N1 infection. Elevation of CK was associated with more complications and increased ICU LOS and healthcare resources.
Assuntos
Creatina Quinase/análise , Vírus da Influenza A Subtipo H1N1 , Influenza Humana/sangue , Insuficiência Respiratória/sangue , Adulto , Biomarcadores/sangue , Feminino , Humanos , Influenza Humana/complicações , Unidades de Terapia Intensiva/estatística & dados numéricos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Estudos Multicêntricos como Assunto , Prognóstico , Estudos Prospectivos , Insuficiência Respiratória/etiologia , Rabdomiólise/sangue , Rabdomiólise/etiologia , Índice de Gravidade de Doença , EspanhaRESUMO
Infections caused by Gram-positive bacteria are a serious problem and is associated with high mortality. Among them, we should highlight those caused by methicillin-resistant Staphylococcus aureus (MRSA). Primary bacteremia, catheter-related bloodstream infections and constitute the main presentations. Vancomycin has traditionally been the treatment of choice for these infections, but its activity is not satisfactory especially in cases of MRSA with minimum inhibitory concentration (MIC) > 1 mg/L. Daptomycin is a lipopeptide antibiotic active against Gram-positive bacteria including MRSA and glycopeptide-resistant Enterococcus spp.It is worth mentioning that daptomycin is rapidly bactericidal against methicillin-sensitive S. aureus, more potent than vancomycin and at least as active as isoxazole penicillins. This article discusses the role of this antibiotic in the empirical treatment of infections and directed by Gram-positive bacteria affecting critically ill patients.
Assuntos
Antibacterianos/uso terapêutico , Daptomicina/uso terapêutico , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Cuidados Críticos , Estado Terminal , Daptomicina/farmacologia , Farmacorresistência Bacteriana , Bactérias Gram-Positivas/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Infecções dos Tecidos Moles/tratamento farmacológico , Infecções dos Tecidos Moles/microbiologia , Vancomicina/uso terapêutico , Resistência a VancomicinaAssuntos
Rejeição de Enxerto/imunologia , Terapia de Imunossupressão/métodos , Transplante de Fígado , Soro Antilinfocitário/uso terapêutico , Carcinoma Hepatocelular/cirurgia , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/etiologia , Administração de Caso , Rejeição de Enxerto/prevenção & controle , Infecções por HIV/complicações , Hepatite C/complicações , Humanos , Imunossupressores/classificação , Imunossupressores/farmacologia , Imunossupressores/uso terapêutico , Falência Renal Crônica/complicações , Neoplasias Hepáticas/cirurgia , Risco , Linfócitos TRESUMO
Selective protein degradation by the ubiquitin-proteosome pathway has recently emerged as a powerful regulatory mechanism in a wide variety of cellular processes. Ubiquitin conjugation requires the sequential activity of three enzymes or protein complexes called the ubiquitin-activating enzyme (E1), the ubiquitin-conjugating enzyme (E2), and the ubiquitin-protein ligase (E3). In most eukaryotes, there are a small number of similar E1 isoforms without apparent functional specificity. The specific selection of target proteins is accomplished by the E2 and E3 proteins. One of the best-characterized families of E3s are the SCF complexes. The SCF is composed of a cullin (Cdc53), SKP1, RBX1 and one member of a large family of proteins called F-box proteins. The function of the F-box protein is to interact with target proteins. In some cases, the stability of the F-box protein may regulate activity of the SCF complex. In addition, post-translational modification of the cullin subunit by the ubiquitin-like protein RUB/NEDD8 appears to regulate SCF function. In plants, the SCF has so far been implicated in floral development, circadian clock, and response to the plant growth regulators auxin and jasmonic acid.
Assuntos
Peptídeo Sintases/metabolismo , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Peptídeo Sintases/genética , Proteínas de Plantas/genética , Proteínas Ligases SKP Culina F-Box , Homologia de Sequência de AminoácidosRESUMO
The ubiquitin-like protein RUB1 is conjugated to target proteins by a mechanism similar to that of ubiquitin conjugation. Genetic studies in Arabidopsis thaliana have implicated the RUB-conjugation pathway in auxin response. The first step in the pathway is RUB activation by a bipartite enzyme composed of the AXR1 and ECR1 proteins. Ubiquitin activation is an ATP-dependent process that involves the formation of an AMP-ubiquitin intermediate. Here we show that RUB activation by AXR1-ECR1 also involves formation of an AMP-RUB intermediate and that this reaction is catalyzed by the ECR1 subunit alone. In addition, we identified an Arabidopsis protein called RCE1 that is a likely RUB-conjugating enzyme. RCE1 works together with AXR1-ECR1 to promote formation of a stable RUB conjugate with the Arabidopsis cullin AtCUL1 in vitro. Using a tagged version of RUB1, we show that this modification occurs in vivo. Because AtCUL1 is a component of the ubiquitin protein ligase SCF(TIR1), a complex that also functions in auxin response, we propose that RUB modification of AtCUL1 is important for auxin response.
Assuntos
Proteínas de Arabidopsis , Substâncias de Crescimento , Ligases/metabolismo , Proteínas de Plantas/metabolismo , Processamento de Proteína Pós-Traducional , Ubiquitinas/metabolismo , Monofosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Arabidopsis , Sequência Conservada , Ésteres , Ligases/isolamento & purificação , Dados de Sequência Molecular , Homologia de Sequência de Aminoácidos , Compostos de Sulfidrila , Enzimas de Conjugação de Ubiquitina , Ubiquitina-Proteína LigasesRESUMO
Studies on the CDC6 protein, which is crucial to the control of DNA replication in yeast and animal cells, are lacking in plants. We have isolated an Arabidopsis cDNA encoding the AtCDC6 protein and studied its possible connection to the occurrence of developmentally regulated endoreplication cycles. The AtCDC6 gene is expressed maximally in early S-phase, and its promoter contains an E2F consensus site that mediates the binding of a plant E2F/DP complex. Transgenic plants carrying an AtCDC6 promoter-beta-glucuronidase fusion revealed that it is active in proliferating cells and, interestingly, in endoreplicating cells. In particular, the extra endoreplication cycle that occurs in dark-grown hypocotyl cells is associated with upregulation of the AtCDC6 gene. This was corroborated using ctr1 Arabidopsis mutants altered in their endoreplication pattern. The ectopic expression of AtCDC6 in transgenic plants induced endoreplication and produced a change in the somatic ploidy level. AtCDC6 was degraded in a ubiquitin- and proteosome-dependent manner by extracts from proliferating cells, but it was degraded poorly by extracts from dark-grown hypocotyl endoreplicating cells. Our results indicate that endoreplication is associated with expression of the AtCDC6 gene and, most likely, the stability of its product; it also apparently requires activation of the retinoblastoma/E2F/DP pathway. These conclusions may apply to endoreplicating cells in other tissues of the plant and to endoreplicating cells in other eukaryotes.
Assuntos
Arabidopsis/genética , Proteínas de Ciclo Celular/genética , Replicação do DNA/genética , Proteínas de Ligação a DNA , Proteínas de Saccharomyces cerevisiae , Sequência de Aminoácidos , Animais , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Ciclo Celular/classificação , Proteínas de Ciclo Celular/metabolismo , Ritmo Circadiano , Escuridão , Fatores de Transcrição E2F , Regulação da Expressão Gênica de Plantas , Humanos , Luz , Camundongos , Mitose , Dados de Sequência Molecular , Filogenia , Ploidias , Regiões Promotoras Genéticas , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
The increase in the ratio of root growth to shoot growth that occurs in response to phosphate (Pi) deprivation is paralleled by a decrease in cytokinin levels under the same conditions. However, the role of cytokinin in the rescue system for Pi starvation remains largely unknown. We have isolated a gene from Arabidopsis thaliana (AtIPS1) that is induced by Pi starvation, and studied the effect of cytokinin on its expression in response to Pi deprivation. AtIPS1 belongs to the TPSI1/Mt4 family, the members of which are specifically induced by Pi starvation, and the RNAs of which contain only short, non-conserved open reading frames. Pi deprivation induces AtIPS1 expression in all cells of wild-type plants, whereas in the pho1 mutant grown on Pi-rich soils, AtIPS1 expression in the root was delimited by the endodermis. This supports the view that pho1 is impaired in xylem loading of Pi, and that long-distance signals controlling the Pi starvation responses act via negative control. Exogenous cytokinins repress the expression of AtIPS1 and other Pi starvation-responsive genes in response to Pi deprivation. However, cytokinins did not repress the increase in root-hair number and length induced by Pi starvation, a response dependent on local Pi concentration rather than on whole-plant Pi status. Our results raise the possibility that cytokinins may be involved in the negative modulation of long-distance, systemically controlled Pi starvation responses, which are dependent on whole-plant Pi status.
Assuntos
Arabidopsis/efeitos dos fármacos , Citocininas/farmacologia , Genes de Plantas/genética , Fosfatos/farmacologia , Proteínas de Plantas/genética , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Sequência de Bases , DNA Complementar/química , DNA Complementar/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucuronidase/genética , Glucuronidase/metabolismo , Dados de Sequência Molecular , Mutação , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Plantas Geneticamente Modificadas , Proteínas Recombinantes de Fusão/efeitos dos fármacos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido NucleicoRESUMO
Low phosphorous availability, a common condition of many soils, is known to stimulate phosphatase activity in plants; however, the molecular details of this response remain mostly unknown. We purified and sequenced the N-terminal region of a phosphate starvation induced acid phosphatase (AtACP5) from Arabidopsis thaliana, and cloned its cDNA and the corresponding genomic DNA. The nucleotide sequence of the cDNA predicted that AtACP5 is synthesised as a 338 amino acid-long precursor with a signal peptide. AtACP5 was found to be related to known purple acid phosphatases, especially to mammal type 5 acid phosphatases. Other similarities with purple acid phosphatases, which contain a dinuclear metal centre, include the conservation of all residues involved in metal ligand binding and resistance to tartrate inhibition. In addition, AtACP5, like other type 5 acid phosphatases, displayed peroxidation activity. Northern hybridisation experiments, as well as in situ glucuronidase (GUS) activity assays on transgenic plants harbouring AtACP5:GUS translational fusions, showed that AtACP5 is not only responsive to phosphate starvation but also to ABA and salt stress. It is also expressed in senescent leaves and during oxidative stress induced by H2O2, but not by paraquat or salicylic acid. Given its bifunctionality, as it displays both phosphatase and peroxidation activity, we propose that AtACP5 could be involved in phosphate mobilisation and in the metabolism of reactive oxygen species in stressed or senescent parts of the plant.
Assuntos
Fosfatase Ácida/genética , Arabidopsis/enzimologia , Isoenzimas/genética , Organofosfatos/metabolismo , Estresse Oxidativo , Sequência de Aminoácidos , Arabidopsis/genética , Sequência de Bases , Dados de Sequência Molecular , Plantas Geneticamente Modificadas , Biossíntese de Proteínas , Fosfatase Ácida Resistente a TartaratoRESUMO
The plant hormone auxin regulates diverse aspects of plant growth and development. We report that in Arabidopsis, auxin response is dependent on a ubiquitin-ligase (E3) complex called SCFTIR1. The complex consists of proteins related to yeast Skp1p and Cdc53p called ASK and AtCUL1, respectively, as well as the F-box protein TIR1. Mutations in either ASK1 or TIR1 result in decreased auxin response. Further, overexpression of TIR1 promotes auxin response suggesting that SCFTIR1 is limiting for the response. These results provide new support for a model in which auxin action depends on the regulated proteolysis of repressor proteins.
Assuntos
Proteínas de Arabidopsis , Arabidopsis/enzimologia , Peptídeo Sintases/fisiologia , Proteínas de Plantas/fisiologia , Sequência de Aminoácidos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/farmacologia , Dados de Sequência Molecular , Peptídeo Sintases/genética , Proteínas de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Proteínas Recombinantes de Fusão/fisiologia , Proteínas Ligases SKP Culina F-Box , Alinhamento de SequênciaRESUMO
We conducted a prospective, randomized clinical trial among liver transplant patients to assess the efficacy and safety of weekly sulfadoxine/pyrimethamine compared with daily trimethoprim-sulfamethoxazole in the prevention of Pneumocystis carinii pneumonia. The studied drugs were given during 6 months after transplantation. One hundred twenty patients were included. None of the 60 patients receiving weekly sulfadoxine/pyrimethamine developed Pneumocystis carinii pneumonia, whereas two cases (3%) developed among the 60 patients who received trimethoprim-sulfamethoxazole. For both patients, the studied medication had been discontinued several weeks earlier because of adverse effects. No differences were observed in the incidence of adverse effects. We conclude that weekly sulfadoxine/pyrimethamine is as effective and safe as is daily trimethoprim-sulfamethoxazole in the prophylaxis of Pneumocystis carinii pneumonia after liver transplantation.