Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
1.
Fungal Biol ; 127(7-8): 1198-1208, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37495309

RESUMO

In addition to their role in the breakdown of H2O2, some peroxiredoxins (Prxs) have chaperone and H2O2 sensing functions. Acting as an H2O2 sensor, Prx Gpx3 transfers the oxidant signal to the transcription factor Yap1, involved in the antioxidant response in Saccharomyces cerevisiae. We have shown that Aspergillus nidulans Yap1 ortholog NapA is necessary for the antioxidant response, the utilization of arabinose, fructose and ethanol, and for proper development. To address the Prx roles in these processes, we generated and characterized mutants lacking peroxiredoxins PrxA, PrxB, PrxC, or TpxC. Our results show that the elimination of peroxiredoxins PrxC or TpxC does not produce any distinguishable phenotype. In contrast, the elimination of atypical 2-cysteine peroxiredoxins PrxA and PrxB produce different mutant phenotypes. ΔprxA, ΔnapA and ΔprxA ΔnapA mutants are equally sensitive to H2O2 and menadione, while PrxB is dispensable for this. However, the sensitivity of ΔprxA and ΔprxA ΔnapA mutants is increased by the lack of PrxB. Moreover, PrxB is required for arabinose and ethanol utilization and fruiting body cell wall pigmentation. PrxA expression is partially independent of NapA, and the replacement of peroxidatic cysteine 61 by serine (C61S) is enough to cause oxidative stress sensitivity and prevent NapA nuclear accumulation in response to H2O2, indicating its critical role in H2O2 sensing. Our results show that despite their high similarity, PrxA and PrxB play differential roles in Aspergillus nidulans antioxidant response, carbon utilization and development.


Assuntos
Antioxidantes , Aspergillus nidulans , Antioxidantes/metabolismo , Peroxirredoxinas/genética , Peroxirredoxinas/metabolismo , Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Peróxido de Hidrogênio/metabolismo , Cisteína/metabolismo , Arabinose , Estresse Oxidativo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Etanol , Carbono , Oxirredução
2.
Cells ; 11(7)2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35406759

RESUMO

Cell-penetrating peptides (CPPs) have emerged as a powerful tool for the delivery of otherwise impermeable cargoes into intact cells. Recent efforts to improve the delivery capability of peptides have mainly focused on the identity of the CPP; however, there is evidence that the identity of the cargo itself affects the uptake. The goal of this work was to investigate how the characteristics of a peptide cargo, including net charge and length, either enhance or diminish the internalization efficiency of the CPP/cargo complex. A small library of CPP/cargo complexes were synthesized consisting of structured and unstructured CPPs with cargoes of net positive, negative, or neutral charge and lengths of 4 or 8 amino acids. Cargoes with a net positive charge were found to enhance the overall uptake of the complexes while net neutral and negatively charged cargoes diminished uptake. Conversely, the net length of the cargo had no significant effect on uptake of the CPP/cargo complexes. Microcopy images confirmed the increased uptake of the positively charged cargoes; however, an increase in punctate regions with the addition of a cargo was also observed. The effects of the net positively charged cargoes were confirmed with both structured and unstructured CPPs, which demonstrated similar trends of an increase in uptake with the addition of positively charged residues. These findings demonstrate that the net charge of cargoes impacts the uptake of the complex, which can be considered in the future when designing peptide-based reporters or therapeutics.


Assuntos
Peptídeos Penetradores de Células , Transporte Biológico , Peptídeos Penetradores de Células/química , Peptídeos Penetradores de Células/metabolismo
3.
J Fungi (Basel) ; 7(6)2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34073303

RESUMO

Aspergillus sydowii is a moderate halophile fungus extensively studied for its biotechnological potential and halophile responses, which has also been reported as a coral reef pathogen. In a recent publication, the transcriptomic analysis of this fungus, when growing on wheat straw, showed that genes related to cell wall modification and cation transporters were upregulated under hypersaline conditions but not under 0.5 M NaCl, the optimal salinity for growth in this strain. This led us to study osmolyte accumulation as a mechanism to withstand moderate salinity. In this work, we show that A. sydowii accumulates trehalose, arabitol, mannitol, and glycerol with different temporal dynamics, which depend on whether the fungus is exposed to hypo- or hyperosmotic stress. The transcripts coding for enzymes responsible for polyalcohol synthesis were regulated in a stress-dependent manner. Interestingly, A. sydowii contains three homologs (Hog1, Hog2 and MpkC) of the Hog1 MAPK, the master regulator of hyperosmotic stress response in S. cerevisiae and other fungi. We show a differential regulation of these MAPKs under different salinity conditions, including sustained basal Hog1/Hog2 phosphorylation levels in the absence of NaCl or in the presence of 2.0 M NaCl, in contrast to what is observed in S. cerevisiae. These findings indicate that halophilic fungi such as A. sydowii utilize different osmoadaptation mechanisms to hypersaline conditions.

4.
Rev. méd. Chile ; 148(5): 689-696, mayo 2020. tab
Artigo em Espanhol | LILACS | ID: biblio-1139354

RESUMO

Coronavirus infection (SARS-CoV-2), is a pandemic disease declared by the World Health Organization (WHO). This disease reports a high risk of contagion, especially by the transmission of aerosols in health care workers. In this scenario, aerosol exposure is increased in various procedures related to the airway, lungs, and pleural space. For this reason, it is important to have recommendations that reduce the risk of exposure and infection with COVID-19. In this document, a team of international specialists in interventional pulmonology elaborated a series of recommendations, based on the available evidence to define the risk stratification, diagnostic methods and technical considerations on procedures such as bronchoscopy, tracheostomy, and pleural procedures among others. As well as the precautions to reduce the risk of contagion when carrying out pulmonary interventions.


Assuntos
Humanos , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Infecções por Coronavirus/prevenção & controle , Pandemias , Controle de Infecções
5.
Rev Med Chil ; 148(5): 689-696, 2020 May.
Artigo em Espanhol | MEDLINE | ID: mdl-33399763

RESUMO

Coronavirus infection (SARS-CoV-2), is a pandemic disease declared by the World Health Organization (WHO). This disease reports a high risk of contagion, especially by the transmission of aerosols in health care workers. In this scenario, aerosol exposure is increased in various procedures related to the airway, lungs, and pleural space. For this reason, it is important to have recommendations that reduce the risk of exposure and infection with COVID-19. In this document, a team of international specialists in interventional pulmonology elaborated a series of recommendations, based on the available evidence to define the risk stratification, diagnostic methods and technical considerations on procedures such as bronchoscopy, tracheostomy, and pleural procedures among others. As well as the precautions to reduce the risk of contagion when carrying out pulmonary interventions.


Assuntos
COVID-19/prevenção & controle , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Pandemias , Humanos , Controle de Infecções
6.
Rev. cuba. hematol. inmunol. hemoter ; 35(1): e916, ene.-mar. 2019. tab, graf
Artigo em Espanhol | LILACS, CUMED | ID: biblio-1003891

RESUMO

La neutropenia se define como un recuento absoluto de neutrófilos menor a 1500 células /µL. Se debe a la disminución en la producción de granulocitos o al aumento en su destrucción, ya sea a nivel medular o periférico. Según la clasificación de la Organización Mundial de la Salud (OMS) los grados de neutropenia van de 0 a IV, de acuerdo a la magnitud de la disminución del recuento de neutrófilos. El grado IV es el de mayor riesgo y corresponde a recuentos por debajo de 500 células/µL. El impacto en la morbimortalidad asociada a la neutropenia no está vinculado con la disminución directa del recuento celular, sino con los procesos infecciosos asociados a los que son propensos los pacientes que la presentan. Existen diversas condiciones por las que se puede desarrollar neutropenia, entre las que se encuentran las infecciones, las malignidades y los fármacos. Estos últimos pueden generar eventos adversos por mecanismos dosis dependiente, como en el caso de la quimioterapia citotóxica o por una reacción idiosincrática. Se presenta el caso de una paciente femenina de 37 años de edad, con antecedentes de tirotoxicosis, tratada con propanolol y metimazol durante cuatro semanas, quien además de manifestaciones tóxicas, presentó neutropenia febril muy grave, que mejoró luego de suspensión del antitiroideo. Se pretende resaltar la asociación de neutropenia febril como complicación de uso de tionamidas y la importancia del seguimiento con exámenes de laboratorios para un diagnóstico oportuno(AU)


Neutropenia is defined as an absolute neutrophil count less than 1500 cells / μL. It is due to the decrease in the production of granulocytes or increase in their destruction, either at the medullary or peripheral level. According to the classification of the World Health Organization (WHO) the degrees of neutropenia range from 0 to IV, taking into account the magnitude of the decrease in the neutrophil count. Grade IV is the highest risk and corresponds to counts below 500 cells /μL. The impact on morbidity and mortality associated with neutropenia is not linked to the direct reduction of the cell count, but to the associated infectious processes to which patients who present it are prone. There are several conditions under which neutropenia can develop, including infections, malignancies and drugs. The latter can generate adverse effects by dose-dependent mechanisms, as in the case of cytotoxic chemotherapy or an idiosyncratic reaction. Next, the case of a female patient of thirty-seven years of age, with a history of thyrotoxicosis, treated with propanolol and methimazole for four weeks, who in addition to toxic manifestations, presents very severe febrile neutropenia that improves after suspension of the antithyroid. We aim to highlight the association of febrile neutropenia as a complication of thionamide use and the importance of follow-up with laboratory tests for an opportune diagnosis(AU)


Assuntos
Humanos , Feminino , Adulto , Metimazol/efeitos adversos , Neutropenia/complicações , Neutropenia/diagnóstico , Relatos de Casos , Neutropenia/induzido quimicamente
7.
Front Microbiol ; 9: 2518, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30405576

RESUMO

Stress activated MAP kinases (SAPKs) of the Hog1/Sty1/p38 family are specialized in transducing stress signals. In contrast to what is seen in animal cells, very few fungal species contain more than one SAPK. Aspergillus nidulans and other Aspergilli contain two SAPKs called SakA/HogA and MpkC. We have shown that SakA is essential for conidia to maintain their viability and to survive high H2O2 concentrations. H2O2 induces SakA nuclear accumulation and its interaction with transcription factor AtfA. Although SakA and MpkC show physical interaction, little is known about MpkC functions. Here we show that ΔmpkC mutants are not sensitive to oxidative stress but in fact MpkC inactivation partially restores the oxidative stress resistance of ΔsakA mutants. ΔmpkC mutants display about twofold increase in the production of fully viable conidia. The inactivation of the SakA upstream MAPKK PbsB or the simultaneous elimination of sakA and mpkC result in virtually identical phenotypes, including decreased radial growth, a drastic reduction of conidiation and a sharp, progressive loss of conidial viability. SakA and to a minor extent MpkC also regulate cell-wall integrity. Given the roles of MpkC in conidiation and oxidative stress sensitivity, we used a functional MpkC::GFP fusion to determine MpkC nuclear localization as an in vivo indicator of MpkC activation during asexual development and stress. MpkC is mostly localized in the cytoplasm of intact conidia, accumulates in nuclei during the first 2 h of germination and then becomes progressively excluded from nuclei in growing hyphae. In the conidiophore, MpkC nuclear accumulation increases in vesicles, metulae and phialides and decreases in older conidia. Oxidative and osmotic stresses induce MpkC nuclear accumulation in both germinating conidia and hyphae. In all these cases, MpkC nuclear accumulation is largely dependent on the MAPKK PbsB. Our results indicate that SakA and MpkC play major, distinct and sometimes opposing roles in conidiation and conidiospore physiology, as well as common roles in response to stress. We propose that two SAPKs are necessary to delay (MpkC) or fully stop (SakA) mitosis during conidiogenesis and the terminal differentiation of conidia, in the highly prolific phialoconidiation process characteristic of the Aspergilli.

8.
Plast Reconstr Surg Glob Open ; 6(8): e1906, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30324077

RESUMO

Mephedrone is a new synthetic cathinone-derived drug. It is a sympathomimetic drug, and its structure is similar to amphetamines, although its specific pharmacokinetics and metabolism remain unknown. We performed a literature search in PUBMED with the following key words: Mephedrone AND Necrosis AND Hand. No results were found. We performed a second literature search with the following key words: Mephedrone AND Physiopathology AND Side effects, obtaining a total of 7 articles that we read before writing this case report. We will present a case report of a 28-year-old man with distal ischemia in his left hand associated to intra-arterial drug use of mephedrone. The patient ended up having superficial necrosis involving skin and subcutaneous tissue in his thumb, which was treated with wound care. Good quality healing, full range of motion, and normal sensitivity were achieved. There are no previous publications related to any side effects secondary to its intravascular use. The ultimate mechanism producing this distal fingertip necrosis remains undefined.

9.
J Transl Med ; 16(1): 27, 2018 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-29448967

RESUMO

BACKGROUND: Magnetic stimulation of the facial nerve has been tested in preclinical studies as a new, non-invasive emergency treatment of ischemic stroke that acts by increasing cerebral blood flow (CBF). The objective of the studies reported herein was to identify minimal stimulation parameters that increase CBF in large animals and then test those stimulation parameters in healthy volunteers for safety, tolerability, and effectiveness at increasing CBF. This translational research is necessary preparation for clinical studies in ischemic stroke patients. METHODS: Initial experiments in anesthetized Yorkshire pigs were undertaken in order to identify the lowest stimulus power and duration that increase CBF. A full 3 × 3 factorial design was used to evaluate magnetic stimulation of the facial nerve at various stimulation powers (1.3, 1.6, and 1.9 Tesla field strength at coil surface) and for various durations (2, 3.5, and 5 min). CBF was measured with contrast MRI perfusion imaging and the internal carotid arteries were assessed with MR angiography. Magnetic facial nerve stimulation with parameters identified in the pig study was then applied to 35 healthy volunteers. Safety was assessed with adverse event reports and by medical examination. Tolerability was defined as each volunteer's ability to withstand at least 2 min of stimulation. Volunteers could determine the maximum power of stimulation they received during a ramp-up period. RESULTS: In pigs, unilateral facial nerve stimulation increased CBF by as much as 77% over pre-stimulation baseline when administered across a range of 1.3-1.9 Tesla power and for 2- to 5-min duration. No clear dose-response relationship could be observed across this range, but lower powers and durations than these were markedly less effective. The effect of a single stimulation lasted 90 min. A second stimulation delivered 100 min after the first stimulation sustained the increased CBF without evidence of tachyphylaxis. In human, bilateral facial nerve stimulation caused only non-serious adverse events that were limited to the 2-min stimulation period. Tolerability was greatly improved by gentle encouragement from the study staff, which enabled most volunteers to tolerate 1.6-1.8 Tesla of stimulation power. CBF measures taken approximately 10 min after stimulation demonstrated on average a 32 ± 6% increase in CBF, with ≥ 25% increases in CBF occurring in 10 of the 31 volunteers who had adequate CBF measurements. CONCLUSIONS: The minimal effective stimulation parameters defined by increased CBF, as identified in the pig study, translated into safe, tolerable, and effective stimulation of healthy volunteers. These results support the future development and evaluation of non-invasive facial nerve stimulation for the emergency treatment of ischemic stroke. Trial Registration retrospectively registered with clinicaltrials.gov NRV_P1_01_15 on June 6, 2017.


Assuntos
Isquemia Encefálica/terapia , Tratamento de Emergência , Equipamentos e Provisões , Nervo Facial/fisiopatologia , Voluntários Saudáveis , Magnetismo/instrumentação , Acidente Vascular Cerebral/terapia , Adulto , Animais , Isquemia Encefálica/fisiopatologia , Artérias Carótidas/fisiopatologia , Circulação Cerebrovascular , Feminino , Humanos , Masculino , Perfusão , Acidente Vascular Cerebral/fisiopatologia , Suínos , Adulto Jovem
10.
Front Microbiol ; 8: 516, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28424666

RESUMO

The redox-regulated transcription factors (TFs) of the bZIP AP1 family, such as yeast Yap1 and fission yeast Pap1, are activated by peroxiredoxin proteins (Prxs) to regulate the antioxidant response. Previously, Aspergillus nidulans mutants lacking the Yap1 ortholog NapA have been characterized as sensitive to H2O2 and menadione. Here we study NapA roles in relation to TFs SrrA and AtfA, also involved in oxidant detoxification, showing that these TFs play different roles in oxidative stress resistance, catalase gene regulation and development, during A. nidulans life cycle. We also uncover novel NapA roles in repression of sexual development, normal conidiation, conidial mRNA accumulation, and carbon utilization. The phenotypic characterization of ΔgpxA, ΔtpxA, and ΔtpxB single, double and triple peroxiredoxin mutants in wild type or ΔnapA backgrounds shows that none of these Prxs is required for NapA function in H2O2 and menadione resistance. However, these Prxs participate in a minor NapA-independent H2O2 resistance pathway and NapA and TpxA appear to regulate conidiation along the same route. Using transcriptomic analysis we show that during conidial development NapA-dependent gene expression pattern is different from canonical oxidative stress patterns. In the course of conidiation, NapA is required for regulation of at least 214 genes, including ethanol utilization genes alcR, alcA and aldA, and large sets of genes encoding proteins involved in transcriptional regulation, drug detoxification, carbohydrate utilization and secondary metabolism, comprising multiple oxidoreductases, membrane transporters and hydrolases. In agreement with this, ΔnapA mutants fail to grow or grow very poorly in ethanol, arabinose or fructose as sole carbon sources. Moreover, we show that NapA nuclear localization is induced not only by oxidative stress but also by growth in ethanol and by carbon starvation. Together with our previous work, these results show that SakA-AtfA, SrrA and NapA oxidative stress-sensing pathways regulate essential aspects of spore physiology (i.e., cell cycle arrest, dormancy, drug production and detoxification, and carbohydrate utilization).

11.
Front Microbiol ; 7: 353, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27047469

RESUMO

Aspergillus nidulans asexual sporulation (conidiation) is triggered by different environmental signals and involves the differentiation of specialized structures called conidiophores. The elimination of genes flbA-E, fluG, and tmpA results in a fluffy phenotype characterized by delayed conidiophore development and decreased expression of the conidiation essential gene brlA. While flbA-E encode regulatory proteins, fluG and tmpA encode enzymes involved in the biosynthesis of independent signals needed for normal conidiation. Here we identify afeA and tmpB as new genes encoding members the adenylate-forming enzyme superfamily, whose inactivation cause different fluffy phenotypes and decreased conidiation and brlA expression. AfeA is most similar to unknown function coumarate ligase-like (4CL-Lk) enzymes and consistent with this, a K544N active site modification eliminates AfeA function. TmpB, identified previously as a larger homolog of the oxidoreductase TmpA, contains a NRPS-type adenylation domain. A high degree of synteny in the afeA-tmpA and tmpB regions in the Aspergilli suggests that these genes are part of conserved gene clusters. afeA, tmpA, and tmpB double and triple mutant analysis as well as afeA overexpression experiments indicate that TmpA and AfeA act in the same conidiation pathway, with TmpB acting in a different pathway. Fluorescent protein tagging shows that functional versions of AfeA are localized in lipid bodies and the plasma membrane, while TmpA and TmpB are localized at the plasma membrane. We propose that AfeA participates in the biosynthesis of an acylated compound, either a p-cuomaryl type or a fatty acid compound, which might be oxidized by TmpA and/or TmpB, while TmpB adenylation domain would be involved in the activation of a hydrophobic amino acid, which in turn would be oxidized by the TmpB oxidoreductase domain. Both, AfeA-TmpA and TmpB signals are involved in self-communication and reproduction in A. nidulans.

12.
World J Emerg Med ; 6(3): 191-5, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26401179

RESUMO

BACKGROUND: There are over 15 million children who have cardiac anomalies around the world, resulting in a significant morbidity and mortality. Early recognition and treatment can improve the outcomes and lengthen life-expectancy of these patients. The NIH and WHO have promoted guidelines for screening for congenital cardiac anomalies using ultrasound in rural environments. METHODS: Our study took place in Bocas Del Toro, Panama where a mobile clinic was established for community healthcare screening and ultrasonographic evaluation by medical student volunteers and volunteer clinical faculty. This was a non-blinded, investigational study utilizing a convenience sample of pediatric patients presenting for voluntary evaluation. Seven first-year medical students were recruited for the study. These students underwent a training program for advanced cardiac ultrasound instruction, termed "Pediatric Echocardiography Cardiac Screening (PECS)". RESULTS: Ten patients were enrolled in the study. Nine patients had adequate images as defined by the PECS criteria and were all classified as normal cardiac pathology by the medical students, resulting in a sensitivity and specificity of 100%. A single patient was identified by medical students as having a pathologic pulmonic stenosis. This was confirmed as correct by a blinded ultrasonographer. CONCLUSIONS: In this pilot study, the first-year medical students were able to correctly identify pediatric cardiac anatomy and pathology in rural Panama after undergoing a 12-hour ultrasound PECS training session. We believe that with this knowledge, minimally trained practitioners can be used to screen for cardiac anomalies in rural Panama using ultrasound.

13.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-789718

RESUMO

BACKGROUND: There are over 15 million children who have cardiac anomalies around the world, resulting in a significant morbidity and mortality. Early recognition and treatment can improve the outcomes and lengthen life-expectancy of these patients. The NIH and WHO have promoted guidelines for screening for congenital cardiac anomalies using ultrasound in rural environments. METHODS: Our study took place in Bocas Del Toro, Panama where a mobile clinic was established for community healthcare screening and ultrasonographic evaluation by medical student volunteers and volunteer clinical faculty. This was a non-blinded, investigational study utilizing a convenience sample of pediatric patients presenting for voluntary evaluation. Seven first-year medical students were recruited for the study. These students underwent a training program for advanced cardiac ultrasound instruction, termed "Pediatric Echocardiography Cardiac Screening (PECS)". RESULTS: Ten patients were enrolled in the study. Nine patients had adequate images as defined by the PECS criteria and were all classified as normal cardiac pathology by the medical students, resulting in a sensitivity and specificity of 100%. A single patient was identified by medical students as having a pathologic pulmonic stenosis. This was confirmed as correct by a blinded ultrasonographer. CONCLUSIONS: In this pilot study, the first-year medical students were able to correctly identify pediatric cardiac anatomy and pathology in rural Panama after undergoing a 12-hour ultrasound PECS training session. We believe that with this knowledge, minimally trained practitioners can be used to screen for cardiac anomalies in rural Panama using ultrasound.

14.
Eukaryot Cell ; 11(9): 1132-42, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22798393

RESUMO

In the fungus Aspergillus nidulans, inactivation of the flbA to -E, fluG, fluF, and tmpA genes results in similar phenotypes, characterized by a delay in conidiophore and asexual spore production. flbB to -D encode transcription factors needed for proper expression of the brlA gene, which is essential for asexual development. However, recent evidence indicates that FlbB and FlbE also have nontranscriptional functions. Here we show that fluF1 is an allele of flbD which results in an R47P substitution. Amino acids C46 and R47 are highly conserved in FlbD and many other Myb proteins, and C46 has been proposed to mediate redox regulation. Comparison of ΔflbD and flbD(R47P) mutants uncovered a new and specific role for flbD during sexual development. While flbD(R47P) mutants retain partial function during conidiation, both ΔflbD and flbD(R47P) mutants are unable to develop the peridium, a specialized external tissue that differentiates during fruiting body formation and ends up surrounding the sexual spores. This function, unique among other fluffy genes, does not affect the viability of the naked ascospores produced by mutant strains. Notably, ascospore development in these mutants is still dependent on the NADPH oxidase NoxA. We generated R47K, C46D, C46S, and C46A mutant alleles and evaluated their effects on asexual and sexual development. Conidiation defects were most severe in ΔflbD mutants and stronger in R47P, C46D, and C46S strains than in R47K strains. In contrast, mutants carrying the flbD(C46A) allele exhibited conidiation defects in liquid culture only under nitrogen starvation conditions. The R47K, R47P, C46D, and C46S mutants failed to develop any peridial tissue, while the flbD(C46A) strain showed normal peridium development and increased cleistothecium formation. Our results show that FlbD regulates both asexual and sexual differentiation, suggesting that both processes require FlbD DNA binding activity and that FlbD is involved in the response to nitrogen starvation.


Assuntos
Aspergillus nidulans/genética , Proteínas Fúngicas/metabolismo , Transativadores/metabolismo , Aspergillus nidulans/crescimento & desenvolvimento , Aspergillus nidulans/fisiologia , Proteínas Fúngicas/genética , Deleção de Genes , Mutação , NADPH Oxidases/metabolismo , Nitrogênio/metabolismo , Reprodução Assexuada/genética , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Transativadores/genética
15.
Mol Microbiol ; 80(2): 436-54, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21320182

RESUMO

Fungi utilize a phosphorelay system coupled to a MAP kinase module for sensing and processing environmental signals. In Aspergillus nidulans, response regulator SskA transmits osmotic and oxidative stress signals to the stress MAPK (SAPK) SakA. Using a genetic approach together with GFP tagging and molecular bifluorescence we show that SakA and ATF/CREB transcription factor AtfA define a general stress-signalling pathway that plays differential roles in oxidative stress responses during growth and development. AtfA is permanently localized in the nucleus, while SakA accumulates in the nucleus in response to oxidative or osmotic stress signals or during normal spore development, where it physically interacts with AtfA. AtfA is required for expression of several genes, the conidial accumulation of SakA and the viability of conidia. Furthermore, SakA is active (phosphorylated) in asexual spores, remaining phosphorylated in dormant conidia and becoming dephosphorylated during germination. SakA phosphorylation in spores depends on certain (SskA) but not other (SrrA and NikA) components of the phosphorelay system. Constitutive phosphorylation of SakA induced by the fungicide fludioxonil prevents both, germ tube formation and nuclear division. Similarly, Neurospora crassa SakA orthologue OS-2 is phosphorylated in intact conidia and gets dephosphorylated during germination. We propose that SakA-AtfA interaction regulates gene expression during stress and conidiophore development and that SAPK phosphorylation is a conserved mechanism to regulate transitions between non-growing (spore) and growing (mycelia) states.


Assuntos
Aspergillus nidulans/fisiologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Regulação Fúngica da Expressão Gênica , Mapeamento de Interação de Proteínas , Esporos Fúngicos/crescimento & desenvolvimento , Estresse Fisiológico , Fatores de Transcrição/metabolismo , Aspergillus nidulans/crescimento & desenvolvimento , DNA Fúngico/química , DNA Fúngico/genética , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Dados de Sequência Molecular , Ligação Proteica , Análise de Sequência de DNA
16.
Med Clin (Barc) ; 130(5): 188-96, 2008 Feb 16.
Artigo em Espanhol | MEDLINE | ID: mdl-18341835

RESUMO

Type 2 diabetes is a disease with an increasing prevalence due to the ageing and sedentary lifestyle of the general population. Its associated with the risk of developing a series of chronic complications in mid/long-term. The current guidelines recommend certain therapy targets that have proven difficult to achieve due to poor compliance or because doctors do not always adhere to expert guidelines. The inability to achieve an adequate glycemic control in the course of diabetes may result in part from the typical conservative stepwise treatment approach that includes monotherapy initiated alter failure of diet and exercise, followed by a combination of oral antiglycemic agents, and ultimately insulin therapy. With respect to insulin therapy, the availability of different analogues as well as the new routes of administration (e.g., inhaled insulin) may allow the early introduction of this therapy, which may be more readily accepted by the patient.


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Árvores de Decisões , Quimioterapia Combinada , Humanos , Insulina/análogos & derivados , Guias de Prática Clínica como Assunto
17.
Med. clín (Ed. impr.) ; 130(5): 188-196, feb. 2008.
Artigo em Es | IBECS | ID: ibc-63505

RESUMO

La diabetes mellitus tipo 2 es una enfermedad cada vez más prevalente por el sedentarismo y el envejecimiento poblacional, y está asociada, a medio-largo plazo, con el riesgo de desarrollar una serie de complicaciones crónicas. Las guías terapéuticas actuales recomiendan objetivos de tratamiento que son inalcanzables para la mayoría de los pacientes, bien por incumplimiento terapéutico o porque el médico no respeta las directrices de los expertos. La incapacidad para alcanzar los adecuados controles glucémicos al inicio del curso evolutivo de la diabetes puede deberse al clásico abordaje conservador y escalonado, que se basa en la monoterapia, tras el fracaso de la dieta y el ejercicio, seguida de tratamiento oral combinado y posterior insulinización sola o en combinación. Con respecto a la insulina, la actual disponibilidad de análogos «a la carta», así como las nuevas formas de administración como la insulina inhalada, puede permitir su introducción temprana sin el rechazo del paciente


Type 2 diabetes is a disease with an increasing prevalence due to the ageing and sedentary lifestyle of the general population. Its associated with the risk of developing a series of chronic complications in mid/long-term. The current guidelines recommend certain therapy targets that have proven difficult to achieve due to poor compliance or because doctors do not always adhere to expert guidelines. The inability to achieve an adequate glycemic control in the course of diabetes may result in part from the typical conservative stepwise treatment approach that includes monotherapy initiated alter failure of diet and exercise, followed by a combination of oral antiglycemic agents, and ultimately insulin therapy. With respect to insulin therapy, the availability of different analogues as well as the new routes of administration (e.g., inhaled insulin) may allow the early introduction of this therapy, which may be more readily accepted by the patient (AU)


Assuntos
Humanos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Guias de Prática Clínica como Assunto/normas , Esquema de Medicação , Quimioterapia Combinada , Índice Glicêmico
18.
Eukaryot Cell ; 6(9): 1570-83, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17630329

RESUMO

Among eukaryotes, only slime molds, fungi, and plants contain signal transduction phosphorelay systems. In filamentous fungi, multiple sensor kinases appear to use a single histidine-containing phosphotransfer (HPt) protein to relay signals to two response regulators (RR). In Aspergillus nidulans, the RR SskA mediates activation of the mitogen-activated protein kinase SakA in response to osmotic and oxidative stress, whereas the functions of the RR SrrA were unknown. We used a genetic approach to characterize the srrA gene as a new member of the skn7/prr1 family and to analyze the roles of SrrA in the phosphorelay system composed of the RR SskA, the HPt protein YpdA, and the sensor kinase NikA. While mutants lacking the HPt protein YpdA are unviable, mutants lacking SskA (DeltasskA), SrrA (DeltasrrA), or both RR (DeltasrrA DeltasskA) are viable and differentially affected in osmotic and oxidative stress responses. Both RR are involved in osmostress resistance, but DeltasskA mutants are more sensitive to this stress, and only SrrA is required for H(2)O(2) resistance and H(2)O(2)-mediated induction of catalase CatB. In contrast, both RR are individually required for fungicide sensitivity and calcofluor resistance and for normal sporulation and conidiospore viability. The DeltasrrA and DeltasskA sporulation defects appear to be related to decreased mRNA levels of the key sporulation gene brlA. In contrast, conidiospore viability defects do not correlate with the activity of the spore-specific catalase CatA. Our results support a model in which NikA acts upstream of SrrA and SskA to transmit fungicide signals and to regulate asexual sporulation and conidiospore viability. In contrast, NikA appears dispensable for osmotic and oxidative stress signaling. These results highlight important differences in stress signal transmission among fungi and define a phosphorelay system involved in oxidative and osmotic stress, cell wall maintenance, fungicide sensitivity, asexual reproduction, and spore viability.


Assuntos
Aspergillus nidulans/fisiologia , Proteínas Fúngicas/fisiologia , Proteínas Quinases Ativadas por Mitógeno/fisiologia , Estresse Oxidativo , Esporos Fúngicos/fisiologia , Antifúngicos/farmacologia , Aspergillus nidulans/efeitos dos fármacos , Aspergillus nidulans/genética , Catalase/genética , Parede Celular , Farmacorresistência Fúngica/genética , Proteínas Fúngicas/genética , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Histidina Quinase , Peróxido de Hidrogênio/farmacologia , Proteínas Quinases Ativadas por Mitógeno/genética , Mutação , Pressão Osmótica , Fosforilação , Proteínas Quinases/metabolismo , RNA Mensageiro/metabolismo , Transdução de Sinais/genética , Esporos Fúngicos/genética
19.
Mol Microbiol ; 59(3): 854-69, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16420356

RESUMO

Asexual reproduction (conidiation) in Aspergillus nidulans is induced by environmental signals like exposure to air or nutrient starvation, and depends on brlA gene activation. The study of 'fluffy' mutants showing delayed asexual development and reduced brlA expression has defined the fluG pathway, involved in regulation of this differentiation process. Genetic characterization of a 'fluffy' mutant identified tmpA as a new gene involved in regulation of conidiation. TmpA defines a new family of putative transmembrane proteins of unknown function, widespread in filamentous fungi and plants, with homologues showing similarity to non-ribosomal peptide synthetases. The deletion of tmpA resulted in decreased brlA expression and conidiation in air-exposed colonies. This defect was suppressed when DeltatmpA mutants were grown next to wild-type or DeltafluG mutant colonies, even without direct contact between hyphae. In liquid culture, tmpA was essential for conidiation induced by nitrogen but not by carbon starvation, whereas the overexpression of different tmpA tagged alleles resulted in conidiation. The overexpression of fluG-induced conidiation independently of tmpA and DeltatmpADeltafluG double mutants showed an additive 'fluffy' phenotype, indicating that tmpA and fluG regulate asexual sporulation through different pathways. TmpA and its homologues appear to have diverged from the ferric reductase family, retaining overall transmembrane architecture, NAD(P), flavin adenine dinucleotide (FAD) and possibly haem-binding domains. Based on our results, we propose that TmpA is a membrane oxidoreductase involved in the synthesis of a developmental signal.


Assuntos
Aspergillus nidulans/crescimento & desenvolvimento , Flavoproteínas/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas de Membrana/metabolismo , Reprodução Assexuada , Aspergillus nidulans/metabolismo , Membrana Celular/química , Membrana Celular/metabolismo , Flavoproteínas/classificação , Flavoproteínas/genética , Proteínas Fúngicas/classificação , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Proteínas de Membrana/classificação , Proteínas de Membrana/genética , Filogenia , Ativação Transcricional
20.
Mol Microbiol ; 45(4): 1153-63, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12180932

RESUMO

In eukaryotic cells, environmental stress signals are transmitted by evolutionarily conserved MAPKs, such as Hog1 in the budding yeast Saccharomyces cerevisiae, Spc1 in the fission yeast Schizosaccharomyces pombe and p38/JNK in mammalian cells. Here, we report the identification of the Aspergillus nidulans sakA gene, which encodes a member of the stress MAPK family. The sakA gene is able to complement the S. pombe spc1- defects in both osmo-regulation and cell cycle progression. Moreover, SakA MAPK is activated in response to osmotic and oxidative stress in both S. pombe and A. nidulans. However, in contrast to hog1 and spc1 mutants, the sakA null mutant is not sensitive to high osmolarity stress, indicating a different regulation of the osmostress response in this fungus. On the other hand, the DeltasakA mutant shows development and cell-specific phenotypes. First, it displays premature steA-dependent sexual development. Second, DeltasakA mutant produces asexual spores that are highly sensitive to oxidative and heat shock stress and lose viability upon storage. Indeed, SakA is transiently activated early after induction of conidiation. Our results indicate that SakA MAPK is involved in stress signal transduction and repression of sexual development, and is required for spore stress resistance and survival.


Assuntos
Aspergillus nidulans/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Estresse Oxidativo , Transdução de Sinais , Esporos Fúngicos , Sequência de Aminoácidos , Aspergillus nidulans/enzimologia , Aspergillus nidulans/genética , Aspergillus nidulans/fisiologia , Sequência de Bases , Clonagem Molecular , Primers do DNA , DNA Complementar , Resposta ao Choque Térmico , Peróxido de Hidrogênio/farmacologia , Proteínas Quinases Ativadas por Mitógeno/química , Proteínas Quinases Ativadas por Mitógeno/genética , Dados de Sequência Molecular , Mutação , Concentração Osmolar , Fosforilação , Schizosaccharomyces/genética , Homologia de Sequência de Aminoácidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...