Induction of the nitrate assimilation nira operon and protein-protein interactions in the maturation of nitrate and nitrite reductases in the cyanobacterium Anabaena sp. strain PCC 7120

Nitrate is widely used as a nitrogen source by cyanobacteria, in which the nitrate assimilation structural genes frequently constitute the so-called nirA operon. This operon contains the genes encoding nitrite reductase (nirA), a nitrate/nitrite transporter (frequently an ABC-type transporter; nrtABCD), and nitrate reductase (narB). In the model filamentous cyanobacterium Anabaena sp. strain PCC 7120, which can fix N2 in specialized cells termed heterocysts, the nirA operon is expressed at high levels only in media containing nitrate or nitrite and lacking ammonium, a preferred nitrogen source. Here we examined the genes downstream of the nirA operon in Anabaena and found that a small open reading frame of unknown function, alr0613, can be cotranscribed with the operon. The next gene in the genome, alr0614 (narM), showed an expression pattern similar to that of the nirA operon, implying correlated expression of narM and the operon. A mutant of narM with an insertion mutation failed to produce nitrate reductase activity, consistent with the idea that NarM is required for the maturation of NarB. Both narM and narB mutants were impaired in the nitrate-dependent induction of the nirA operon, suggesting that nitrite is an inducer of the operon in Anabaena. It has previously been shown that the nitrite reductase protein NirA requires NirB, a protein likely involved in protein-protein interactions, to attain maximum activity. Bacterial two-hybrid analysis confirmed possible NirA-NirB and NarB-NarM interactions, suggesting that the development of both nitrite reductase and nitrate reductase activities in cyanobacteria involves physical interaction of the corresponding enzymes with their cognate partners, NirB and NarM, respectively.Plan Nacional de Investigación y European Regional Development Fund BFU2008-03811 BFU2011-2276

Induction of the nitrate assimilation nira operon and protein-protein interactions in the maturation of nitrate and nitrite reductases in the cyanobacterium Anabaena sp. strain PCC 7120

Nitrate is widely used as a nitrogen source by cyanobacteria, in which the nitrate assimilation structural genes frequently constitute the so-called nirA operon. This operon contains the genes encoding nitrite reductase (nirA), a nitrate/nitrite transporter (frequently an ABC-type transporter; nrtABCD), and nitrate reductase (narB). In the model filamentous cyanobacterium Anabaena sp. strain PCC 7120, which can fix N2 in specialized cells termed heterocysts, the nirA operon is expressed at high levels only in media containing nitrate or nitrite and lacking ammonium, a preferred nitrogen source. Here we examined the genes downstream of the nirA operon in Anabaena and found that a small open reading frame of unknown function, alr0613, can be cotranscribed with the operon. The next gene in the genome, alr0614 (narM), showed an expression pattern similar to that of the nirA operon, implying correlated expression of narM and the operon. A mutant of narM with an insertion mutation failed to produce nitrate reductase activity, consistent with the idea that NarM is required for the maturation of NarB. Both narM and narB mutants were impaired in the nitrate-dependent induction of the nirA operon, suggesting that nitrite is an inducer of the operon in Anabaena. It has previously been shown that the nitrite reductase protein NirA requires NirB, a protein likely involved in protein-protein interactions, to attain maximum activity. Bacterial two-hybrid analysis confirmed possible NirA-NirB and NarB-NarM interactions, suggesting that the development of both nitrite reductase and nitrate reductase activities in cyanobacteria involves physical interaction of the corresponding enzymes with their cognate partners, NirB and NarM, respectively.Plan Nacional de Investigación y European Regional Development Fund BFU2008-03811 BFU2011-2276

Comparison of Microcystis aeruginosa (PCC7820 and PCC7806) growth and intracellular microcystins content determined by liquid chromatography–mass spectrometry, enzyme-linked immunosorbent assay anti-Adda and phosphatase bioassay

Cyanobacteria are able to produce several metabolites that have toxic effects on humans and animals. Among these cyanotoxins, the hepatotoxic microcystins (MC) occur frequently. The intracellular MC content produced by two strains of Microcystis aeruginosa, PCC7806 and PCC7820, and its production kinetics during the culture time were studied in order to elucidate the conditions that favour the growth and proliferation of these toxic strains. Intracellular MC concentrations measured by liquid chromatography (LC) coupled to electrospray ionization mass spectrometer (MS) were compared with those obtained by enzyme-linked immunosorbent assay (ELISA) anti-Adda and protein phosphatase 2A (PP2A) inhibition assays. It has been demonstrated there are discrepancies in the quantification of MC content when comparing ELISA and LC-MS results. However, a good correlation has been obtained between PP2A inhibition assay and LC-MS. Three MC were identified using LC-MS in the PCC7806 strain: MC-LR, demethylated MC-LR and a new variant detected for the first time in this strain, [MeSer7] MC-LR. In PCC7820, MC-LR, D-Asp3-MCLR, Dglu(OCH3)-MCLR, MC-LY, MC-LW and MC-LF were identificated. The major one was MC-LR in both strains, representing 81 and 79% of total MC, respectively. The total MC content in M. aeruginosa PCC7820 was almost three-fold higher than in PCC7806 extracts.Centro de Investigaciones Cietíficas y Técnicas AGL 2006–06523/ AL

Deciphering CHFR role in pancreatic ductal adenocarcinoma

Checkpoint with forkhead-associated and ring finger domains (CHFR) has been proposed as a predictive and prognosis biomarker for different tumor types, but its role in pancreatic ductal adenocarcinoma (PDAC) remains unknown. The aim of this study was two-pronged: to review the role of CHFR in PDAC and evaluating CHFR as a potential predictive biomarker in this disease. For this purpose, we first explored the CHFR messenger (m)RNA expression and promoter methylation through the TCGA database. Secondly, the CHFR expression and promoter methylation were prospectively evaluated in a cohort of patients diagnosed with borderline (n = 19) or resectable (n = 16) PDAC by immunohistochemistry (IHC), methylation specific-PCR (MSP), and pyrosequencing. The results from the TCGA database showed significant differences in terms of progression-free survival (PFS) and overall survival (OS) based on the CHFR mRNA expression, which was likely independent from the promoter methylation. Importantly, our results showed that in primarily resected patients and also the entire cohort, a higher CHFR expression as indicated by the higher IHC staining intensity might identify patients with longer disease-free survival (DFS) and OS, respectively. Similarly, in the same cohorts, patients with lower methylation levels by pyrosequencing showed significantly longer OS than patients without this pattern. Both, the CHFR expression intensity and its promoter methylation were established as independent prognostic factors for PFS and OS in the entire cohort. In contrast, no significant differences were found between different methylation patterns for CHFR and the response to taxane-based neoadjuvant treatment. These results suggest the potential role of the higher expression of CHFR and the methylation pattern of its promoter as potential prognostic biomarkers in PDAC, thus warranting further comprehensive studies to extend and confirm our preliminary findings.This work was funded by grants from the Department of Health from the Government of Navarra (Ref. 008-2018), REFBIO II Pyrenees Biomedical Network from Programa INTERREG V-A España-Francia-Andorra (Ref. BMK_PANC) and Sociedad Española de Oncología Médica (SEOM) to AV. IG-B was supported by a predoctoral fellowship from the Department of Economic Development Government of Navarre Ayudas para la contratación de doctorandos y doctorandas por empresas y organismos de investigación y difusión de conocimientos: doctorados industriales 2018–2020. Intensification Programme Navarrabiomed 2017-2021 Obra Social La Caixa Fundación Caja Navarra. This work has also been supported by the Spanish Ministry of Economy [MINECO; BFU2016-80360-R (to JC)] and the Ministry of Science and Innovation [MICINN; PID2019-105201RB-I00 (to JC)]. Instituto de Salud Carlos III, co-funded by European Union (ERDF/ESF, Investing in your future) [Predoctoral contract FI17/00282 (to EA-P)]. Junta de Andalucía (BIO-0139); GETNE2016 and GETNE2019 Research grants (to JC); and CIBERobn

Selective inhibition of HDAC6 regulates expression of the oncogenic driver EWSR1-FLI1 through the EWSR1 promoter in Ewing sarcoma

Ewing sarcoma (EWS) is an aggressive bone and soft tissue tumor of children and young adults in which the principal driver is a fusion gene, EWSR1-FLI1. Although the essential role of EWSR1-FLI1 protein in the regulation of oncogenesis, survival, and tumor progression processes has been described in-depth, little is known about the regulation of chimeric fusion-gene expression. Here, we demonstrate that the active nuclear HDAC6 in EWS modulates the acetylation status of specificity protein 1 (SP1), consequently regulating the SP1/P300 activator complex binding to EWSR1 and EWSR1-FLI1 promoters. Selective inhibition of HDAC6 impairs binding of the activator complex SP1/P300, thereby inducing EWSR1-FLI1 downregulation and significantly reducing its oncogenic functions. In addition, sensitivity of EWS cell lines to HDAC6 inhibition is higher than other tumor or non-tumor cell lines. High expression of HDAC6 in primary EWS tumor samples from patients correlates with a poor prognosis in two independent series accounting 279 patients. Notably, a combination treatment of a selective HDAC6 and doxorubicin (a DNA damage agent used as a standard therapy of EWS patients) dramatically inhibits tumor growth in two EWS murine xenograft models. These results could lead to suitable and promising therapeutic alternatives for patients with EWS.Research in the E.D.A. lab is supported by Asociación Española Contra el Cáncer (AECC), the Ministry of Science of Spain-FEDER (CIBERONC, PI1700464, PI2000003, RD06/0020/0059)S. D.G.D. and L.H.P. are supported by CIBERONC (CB16/12/00361). D.G.D., M.J.R. and L.H.P. are PhD researchers funded by the Consejería de Salud, Junta de Andalucía (PI-0197-2016, ECAI F2-0012-2018 and PI-0013-2018, respectively).Peer reviewe

We can do it!: nuestros personajes femeninos favoritos

Las siguientes listas son el resultado de una tarea tan formidable como personal: elegir nuestros personajes femeninos favoritos de toda la histor ia del cine. Desde la época muda hasta nuestra era digital, recorr iendo géneros yépocas distintas, diecinueve colaboradores nos dan su opinión

Small bowel enteroscopy - A joint clinical guideline from the spanish and portuguese small bowel study groups

The present evidence-based guidelines are focused on the use of device-assisted enteroscopy in the management of small-bowel diseases. A panel of experts selected by the Spanish and Portuguese small bowel study groups reviewed the available evidence focusing on the main indications of this technique, its role in the management algorithm of each indication and on its diagnostic and therapeutic yields. A set of recommendations were issued accordingly.Estas recomendações baseadas na evidência detalham o uso da enteroscopia assistida por dispositivo no manejo clínico das doenças do intestino delgado. Um conjunto de Gastrenterologistas diferenciados em patologia do intestino delgado foi selecionado pelos grupos de estudos Espanhol e Português de intestino delgado para rever a evidência disponível sobre as principais indicações desta técnica, o seu papel nos algoritmos de manejo de cada indicação e sobre o seu rendimento diagnóstico e terapêutico. Foi gerado um conjunto de recomendações pelos autores

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

Regulación de la asimilación de nitrógeno en la cianobacteria formadora de heterocistos Anabaena sp. PCC7120

Las cianobacterias son capaces de asimilar diferentes fuentes de nitrógeno, como nitrato, nitrito y amonio. Algunas estirpes, como Anabaena SP. PCC 7120, son capaces de fijar nitrógeno atmosférico. El amonio actúa como represor nutricional de la asimilación de fuentes de nitrógeno alternativas. El producto del gen NTCA actúa como un regulador positivo transcripcional de genes regulados por amonio en cianobacterias. Se ha clonado una región del genoma de Anabaena sp. pcc 7120 en la que se sitúa el agrupamiento genético NIR-NRT-ABC implicado en la asimilación de nitrato por tal cianobacteria. Dicho agrupamiento se comporta como operon (Operon Nir), expresándose en ausencia de amonio desde un promotor situado delante del gen NIR cuya utilización es regulada por la proteína NTCA. Por otra parte, se observo que las proteínas NTCA están muy conservadas y que el gen NTCA esta altamente distribuido entre las ianobacterias. La proteína NTCA de anabaena actúa como regulador positivo transcripcional de la expresión de genes reprimibles por amonio y además participa en el proceso de desarrollo de los heterocistos (células especializadas en la fijación de dinitrogeno), en un estadio muy temprano del mismo. Niveles incrementados de expresión de NTCA no suponían expresión en presencia de amonio de los genes que regula

General distribution of the nitrogen control gene ntcA in cyanobacteria

The ntcA gene from Synechococcus sp. strain PCC 7942 encodes a regulatory protein which is required for the expression of all of the genes known to be subject to repression by ammonium in that cyanobacterium. Homologs to ntcA have now been cloned by hybridization from the cyanobacteria Synechocystis sp. strain PCC 6803 and Anabaena sp. strain PCC 7120. Sequence analysis has shown that these ntcA genes would encode polypeptides strongly similar (77 to 79% identity) to the Synechococcus NtcA protein. Sequences hybridizing to ntcA have been detected in the genomes of nine other cyanobacteria that were tested, including strains of the genera Anabaena, Calothrix, Fischerella, Nostoc, Pseudoanabaena, Synechococcus, and Synechocystis.This work was supported by grant B1089-0527 from Comisión Interministerial de Ciencia y Tecnología, by grant PB90-0114 from Dirección General de Investigación Científica y Técnica, and by Junta de Andalucía, Spain. J.E.F. was the recipient of a fellowship from Fundación Cámara Urzaiz-Universidad de Sevilla, Seville, Spain