Browsing by browse.metadata.contributordepartment "Genética y Microbiología"

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    A bacterial light response reveals an orphan desaturase for human plasmalogen synthesis
    Gallego García, Aránzazu; Monera-Girona, Antonio; Pajares-Martínez, Elena; Bastida-Martínez, Eva; Pérez-Castaño, Ricardo; Iniesta Martínez, Antonio Ángel; Fontes Bastos, Marta; Elías Arnanz, Montserrat; Padmanabhan Iyer, Subramanian; Genética y Microbiología
    Plasmalogens are glycerophospholipids with a hallmark sn-1 vinyl ether bond. These lipids are found in animals and some bacteria and have proposed membrane organization, signaling, and antioxidant roles. We discovered the plasmanylethanolamine desaturase activity essential for vinyl ether bond formation in a bacterial enzyme, CarF, which is a homolog of the human enzyme TMEM189. CarF mediates light-induced carotenogenesis in Myxococcus xanthus, and we found that plasmalogens participate in sensing photooxidative stress through singlet oxygen. TMEM189 and other animal homologs could functionally replace CarF in M. xanthus, and knocking out of TMEM189 in a human cell line eliminated plasmalogens. Discovery of the human plasmanylethanolamine desaturase will spur further study of plasmalogen biogenesis, functions, and roles in disease.
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    A histidine kinase and a response regulator provide phage resistance to Marinomonas mediterranea via CRISPR-Cas regulation
    (Nature Research, 2021-10-18) Lucas-Elio, Patricia; Molina-Quintero, Luisa Raquel; Xu, Hengyi; Sánchez-Amat, Antonio; Genética y Microbiología
    CRISPR-Cas systems are used by many prokaryotes to defend against invading genetic elements. In many cases, more than one CRISPR-Cas system co-exist in the same cell. Marinomonas mediterranea MMB-1 possesses two CRISPR-Cas systems, of type I-F and III-B respectively, which collaborate in phage resistance raising questions on how their expression is regulated. This study shows that the expression of both systems is controlled by the histidine kinase PpoS and a response regulator, PpoR, identified and cloned in this study. These proteins show similarity to the global regulators BarA/UvrY. In addition, homologues to the sRNAs CsrB and CsrC and the gene coding for the post-transcriptional repressor CsrA have been also identified indicating the conservation of the elements of the BarA/UvrY regulatory cascade in M. mediterranea. RNA-Seq analyses have revealed that all these genetics elements are regulated by PpoS/R supporting their participation in the regulatory cascade. The regulation by PpoS and PpoR of the CRISPR-Cas systems plays a role in phage defense since mutants in these proteins show an increase in phage sensitivity.
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    A new putative Caulimoviridae genus discovered through air metagenomics
    (American Society for Microbiology, 2018-10-11) Rastrojo, Alberto; Núñez, Andrés; Moreno, Diego A.; Alcamí, Antonio; Genética y Microbiología
    Members of the Caulimoviridae family are important plant pathogens. These circular double-stranded DNA viruses may integrate into the host genome, although this integration is not required for the viral replication cycle. Here, we describe three complete genomes belonging to a new putative Caulimoviridae genus discovered through air metagenomics.
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    A non-canonical RNAi pathway controls virulence and genome stability in Mucorales
    (2020) Pérez Arques, Carlos; Navarro Mendoza, María Isabel; Murcia Flores, L.; Navarro Ros, Eusebio; Garre Mula, Victoriano; Nicolás Molina, Francisco Esteban; Genética y Microbiología
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    A reverse transcriptase-Cas1 fusion protein contains a Cas6 domain required for both CRISPR RNA biogenesis and RNA spacer acquisition
    (Cell Press, 2018-11-15) Mohr, Georg; Silas, Sukrit; Stamos, Jennifer L.; Makarova, Kira S.; Markham, Laura M.; Yao, Jun; Elío Lucas, Patrícia; Sánchez Amat, Antonio; Fire, Andrew Z.; Koonin, Eugene V.; Lambowitz, Alan M.; Genética y Microbiología
    Prokaryotic CRISPR-Cas systems provide adaptive immunity by integrating portions of foreign nucleic acids (spacers) into genomic CRISPR arrays. Cas6 proteins then process CRISPR array transcripts into spacer-derived RNAs (CRISPR RNAs; crRNAs) that target Cas nucleases to matching invaders. We find that a Marinomonas mediterranea fusion protein combines three enzymatic domains (Cas6, reverse transcriptase [RT], and Cas1), which function in both crRNA biogenesis and spacer acquisition from RNA and DNA. We report a crystal structure of this divergent Cas6, identify amino acids required for Cas6 activity, show that the Cas6 domain is required for RT activity and RNA spacer acquisition, and demonstrate that CRISPR-repeat binding to Cas6 regulates RT activity. Co-evolution of putative interacting surfaces suggests a specific structural interaction between the Cas6 and RT domains, and phylogenetic analysis reveals repeated, stable association of free-standing Cas6s with CRISPR RTs in multiple microbial lineages, indicating that a functional interaction between these proteins preceded evolution of the fusion.
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    A ribonuclease III involved in virulence of Mucorales fungi has evolved to cut exclusively single-stranded RNA
    (2021) Falk, Sebastian; Zapata Pérez, Rubén; Sánchez Ferrer, Álvaro; Nicolás Molina, Francisco Esteban; Sánchez Ferrer, Álvaro; Navarro Ros, Eusebio; Garre Mula, Victoriano; Padmanabhan Iyer, Subramanian; Cánovas Márquez, José Tomás; Genética y Microbiología
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    A simple MALDI–TOF-MS method for the identification of non-mycobacterial aerobic actinomycetes growing on blood agar subcultures from positive MGIT cultures
    (Elsevier, 2025) Muñoz-Dávila, María José; Cabezas Fernández, María Teresa; Esteban García, Ana Belén; Martínez Lorila, Miguel José; Genética y Microbiología
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    Activation of the cell integrity pathway is channelled through diverse signalling elements in fission yeast
    (ELSEVIER, 2008-01-04) Barba, Gregorio; Soto, Teresa; Madrid, Marisa; Núñez, Andrés; Vicente, Jero; Gacto, Mariano; Cansado Vizoso, José; Genética y Microbiología
    MAPK Pmk1p is the central element of a cascade involved in the maintenance of cell integrity and other functions in Schizosaccharomyces pombe. Pmk1p becomes activated by multiple stressing situations and also during cell separation. GTPase Rho2p acts upstream of the protein kinase C homolog Pck2p to activate the Pmk1 signalling pathway through direct interaction with MAPKKK Mkh1p. In this work we analyzed the functional significance of both Rho2p and Pck2p in the transduction of various stress signals by the cell integrity pathway. The results indicate that basal Pmk1p activity can be positively regulated by alternative mechanisms which are independent on the control by Rho2p and/or Pck2p. Unexpectedly, Pck1p, another protein kinase C homolog, negatively modulates Pmk1p basal activity by an unknown mechanism. Moreover, different elements appear to regulate the stress-induced activation of Pmk1p depending on the nature of the triggering stimuli. Whereas Pmk1p activation induced by hyper- or hypotonic stresses is channeled through Rho2p–Pck2p, other stressors, like glucose deprivation or cell wall disturbance, are transduced via other pathways in addition to that of Rho2p–Pck2p. On the contrary, Pmk1p activation observed during cell separation or after treatment with hydrogen peroxide does not involve Rho2p–Pck2p. Finally, Pck2p function is critical to maintain a Pmk1p basal activity that allows Pmk1p activation induced by heat stress. These data demonstrate the existence of a complex signalling network modulating Pmk1p activation in response to a variety of stresses in fission yeast.
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    Adherence to the Mediterranean Diet and Determinants Among Pregnant Women: The NELA Cohort
    (MDPI, 2021-04) Suárez-Martíne z, C; Yagüe-Guirao, G; Peso-Echarri, P; Vioque, J; Martínez-Graciá, C; Nela Study Group, .; Santaella-Pascual, Marina; Morales Bartolomé, Eva; García-Marcos Álvarez, Luis Vicente; Genética y Microbiología
    La dieta mediterránea representa uno de los patrones dietéticos más estudiados; sin embargo, no existe una herramienta única para medir el grado de adherencia ni un conjunto único de criterios para adaptar estos índices a las mujeres embarazadas. Caracterizamos la adherencia a la dieta mediterránea (MDA) de las mujeres embarazadas que participaron en la cohorte NELA (Nutrition in Early Life and Asthma) e identificamos los determinantes sociodemográficos y los hábitos de estilo de vida asociados con un mayor riesgo de una MDA baja. La dieta materna durante la gestación se evaluó mediante un Cuestionario de Frecuencia Alimentaria (FFQ) validado (n = 665). Estimamos la puntuación de la Dieta Mediterránea Relativa (rMED), la puntuación de la Dieta Mediterránea Alternativa (aMED) y el Índice Alternativo de Alimentación Saludable-2010 (AHEI-2010). Se realizaron modelos de regresión multivariados para identificar los factores sociodemográficos y de estilo de vida asociados a cada índice. Las madres con menor edad y más partos previos tuvieron mayor probabilidad de MDA baja (p < 0,05). Sólo para el índice aMED, las madres con formación universitaria y/o que practicaban actividades deportivas durante dos o más horas semanales tuvieron menor probabilidad de tener una MDA baja (p < 0,01). Los tres índices clasificaron a la cohorte NELA como de nivel medio de adherencia. Estos resultados pueden mejorarse mediante el diseño de estrategias de intervención y recomendaciones dietéticas para la salud tanto materna como infantil.
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    Antagonistic effect in vitro of three commercial strains of Bacillus sp. against the forest pathogen Diplodia corticola
    (WILEY, 2021) Muñoz‐Adalia, E. Jordán; Meijer, Andreu; Campillo‐Brocal, Jonatan C.; Colinas, Carlos; Genética y Microbiología
    Botryosphaeria canker of Quercus suber (causal agent: Diplodia corticola) poses a major threat for cork production along the western Mediterranean Basin. Infection by D. corticola induces cankers, which reduce tree vigour and compromise phellem regeneration. European policies in forest health advise the use of environmentally friendly methods, such as biocontrol, rather than the use of chemicals in natural stands. In this study, we assessed the antagonistic potential of three commercial products involving bacteria (Bacillus amyloliquefaciens and Bacillus mojavensis) using two culture media [potato-dextrose-agar medium (PDA), and PDA amended with copper oxychloride, an inorganic fungicide] against D. corticola. Five indices based on colony dimensions showed significant antagonistic effects of bacteria on fungal growth in vitro. The copper salt showed high toxicity against D. corticola. Preliminary results suggest that the three commercial products might be used as biocontrol agents against D. corticola, whose control capacities in the field deserve further investigation.
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    Aplicaciones de la PCR en el diagnóstico de un brote de legionelosis
    (2008-07-15) Vera Sánchez, María del Mar; Yagüe Guirao, Genoveva; Segovia Hernández, Manuel; Genética y Microbiología; Biología
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    Artemisia pollen is the main vector for airborne endotoxin
    (Elsevier, 2018-08-09) Oteros, José; Bartusel, Elke; Alessandrini, Francesca; Núñez, Andrés; Moreno, Diego A.; Behrendt, Heidrun; Schmidt-Weber, Carsten; Traidl-Hoffmann, Claudia; Buters, Jeroen; Genética y Microbiología
    Background: Endotoxin (LPS) released from gram-negative bacteria causes strong immunologic and inflammatory effects and, when airborne, can contribute to respiratory conditions, such as allergic asthma. Objectives: We sought to identify the source of airborne endotoxin and the effect of this endotoxin on allergic sensitization. Methods: We determined LPS levels in outdoor air on a daily basis for 4 consecutive years in Munich (Germany) and Davos (Switzerland). Air was sampled as particulate matter (PM) greater than 10 μm (PM > 10) and PM between 2.5 and 10 μm. LPS levels were determined by using the recombinant Factor C assay. Results: More than 60% of the annual endotoxin exposure was detected in the PM > 10 fraction, showing that bacteria do not aerosolize as independent units or aggregates but adhered to large particles. In Munich 70% of annual exposure was detected between June 12th and August 28th. Multivariate modeling showed that endotoxin levels could be explained by phenological parameters (ie, plant growth). Indeed, days with high airborne endotoxin levels correlated well with the amount of Artemisia pollen in the air. Pollen collected from plants across Europe (100 locations) showed that the highest levels of endotoxin were detected on Artemisia vulgaris (mugwort) pollen, with little on other pollen. Microbiome analysis showed that LPS concentrations on mugwort pollen were related to the presence of Pseudomonas species and Pantoea species communities. In a mouse model of allergic disease, the presence of LPS on mugwort pollen was needed for allergic sensitization. Conclusions: The majority of airborne endotoxin stems from bacteria dispersed with pollen of only one plant: mugwort. This LPS was essential for inducing inflammation of the lung and allergic sensitization.
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    Assessment and statistical modelling of airborne microorganisms in Madrid
    (Elsevier, 2020-11-21) Cordero, José María; Núñez, Andrés; García, Ana M.; Borge, Rafael; Genética y Microbiología
    The limited evidence available suggests that the interaction between chemical pollutants and biological particles may intensify respiratory diseases caused by air pollution in urban areas. Unlike air pollutants, which are routinely measured, records of biotic component are scarce. While pollen concentrations are daily surveyed in most cities, data related to airborne bacteria or fungi are not usually available. This work presents the first effort to understand atmospheric pollution integrating both biotic and abiotic agents, trying to identify relationships among the Proteobacteria, Actinobacteria and Ascomycota phyla with palynological, meteorological and air quality variables using all biological historical records available in the Madrid Greater Region. The tools employed involve statistical hypothesis contrast tests such as Kruskal-Wallis and machine learning algorithms. A cluster analysis was performed to analyse which abiotic variables were able to separate the biotic variables into groups. Significant relationships were found for temperature and relative humidity. In addition, the relative abundance of the biological phyla studied was affected by PM10 and O3 ambient concentration. Preliminary Generalized Additive Models (GAMs) to predict the biotic relative abundances based on these atmospheric variables were developed. The results (r = 0.70) were acceptable taking into account the scarcity of the available data. These models can be used as an indication of the biotic composition when no measurements are available. They are also a good starting point to continue working in the development of more accurate models and to investigate causal relationships.
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    B12-based photoreceptors: from structure and function to applications in optogenetics and synthetic biology
    (2019-08) Pérez-Castaño, Ricardo; Elías Arnanz, Montserrat; Padmanabhan Iyer, Subramanian; Genética y Microbiología
    Vitamin B12-based photoreceptor proteins sense ultraviolet (UV), blue or green light using 5´-deoxyadenosylcobalamin (AdoCbl). The prototype of this widespread bacterial photoreceptor family, CarH, controls light-dependent gene expression in photoprotective cellular responses. It represses transcription in the dark by binding to operator DNA as an AdoCbl-bound tetramer, whose disruption by light relieves operator binding to allow transcription. Structures of the "dark" (free and DNA-bound) and "light" CarH states and studies on the unusual AdoCbl photochemistry have provided fundamental insights into these photoreceptors. We highlight these, the plasticity within a conserved mode of action among CarH homologs, their distribution, and their promising applications in optogenetics and synthetic biology.
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    Calnexin is essential for survival under nitrogen starvation and stationary phase in Schizosaccharomyces pombe
    (Public Library of Science, 2015-03-24) Núñez, Andrés; Dulude, Dominic; Jbel, Mehdi; Rokeach, Luis A.; Genética y Microbiología
    Cell fate is determined by the balance of conserved molecular mechanisms regulating death (apoptosis) and survival (autophagy). Autophagy is a process by which cells recycle their organelles and macromolecules through degradation within the vacuole in yeast and plants, and lysosome in metazoa. In the yeast Schizosaccharomyces pombe, autophagy is strongly induced under nitrogen starvation and in aging cells. Previously, we demonstrated that calnexin (Cnx1p), a highly conserved transmembrane chaperone of the endoplasmic reticulum (ER), regulates apoptosis under ER stress or inositol starvation. Moreover, we showedthat in stationary phase, Cnx1p is cleaved into two moieties, L_Cnx1p and S_Cnx1p. Here, weshowthattheprocessing of Cnx1p is regulated by autophagy, induced by nitrogen starvation or cell aging. The cleavage of Cnx1p involves two vacuolar proteases: Isp6, which is essential for autophagy, and its paralogue Psp3. Blocking autophagy through the knockout of autophagy-related genes (atg) results in inhibition of both, the cleavage and the trafficking of Cnx1p from the ER to the vacuole. We demonstrate that Cnx1pis required for cell survival under nitrogen-starvation and in chronological aging cultures. The death of the mini_cnx1 mutant (overlapping S_cnx1p) cells is accompanied by accumulation of high levels of reactive-oxygen species (ROS), a slowdown in endocytosis and severe cell-wall defects. Moreover, mutant cells expressing only S_Cnx1p showed cell wall defects. Co-expressing mutant overlapping the L_Cnx1p and S_Cnx1p cleavage products reverses the death, ROS phenotype and cell wall defect to wild-type levels. As it is involved in both apoptosis and autophagy, Cnx1p could be a nexus for the crosstalk between these pro-death and pro-survival mechanisms. Ours, and observations in mammalian systems, suggest that the multiple roles of calnexin depend on its sub-cellular localization and onits cleavage. The use of S. pombeshouldassist in further shedding light on the multiple roles of calnexin.
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    cAMP-Protein Kinase A and Stress-Activated MAP Kinase 1 signaling mediate transcriptional control of autophagy in fission yeast during glucose limitation or starvation.
    (Taylor and Francis Group, 2022-09-26) Pérez Díaz, Armando Jesús; Vázquez Marín, Beatriz; Vicente Soler, Jero; Prieto Ruiz, Francisco; Soto, Teresa; Franco, Alejandro; Cansado Vizoso, José; Madrid, Marisa; Genética y Microbiología
    Macroautophagy/autophagy is an essential adaptive physiological response in eukaryotes induced during nutrient starvation, including glucose, the primary immediate carbon and energy source for most cells. Although the molecular mechanisms that induce autophagy during glucose starvation have been extensively explored in the budding yeast Saccharomyces cerevisiae, little is known about how this coping response is regulated in the evolutionary distant fission yeast Schizosaccharomyces pombe. Here, we show that S. pombe autophagy in response to glucose limitation relies on mitochondrial respiration and the electron transport chain (ETC), but, in contrast to S. cerevisiae, the AMP-activated protein kinase (AMPK) and DNA damage response pathway components do not modulate fission yeast autophagic flux under these conditions. In the presence of glucose, the cAMP-protein kinase A (PKA) signaling pathway constitutively represses S. pombe autophagy by downregulating the transcription factor Rst2, which promotes the expression of respiratory genes required for autophagy induction under limited glucose availability. Furthermore, the stress-activated protein kinase (SAPK) signaling pathway, and its central mitogen-activated protein kinase (MAPK) Sty1, positively modulate autophagy upon glucose limitation at the transcriptional level through its downstream effector Atf1 and by direct in vivo phosphorylation of Rst2 at S292. Thus, our data indicate that the signaling pathways that govern autophagy during glucose shortage or starvation have evolved differently in S. pombe and uncover the existence of sophisticated and multifaceted mechanisms that control this self-preservation and survival response.
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    Chapter 2: Bacterial Laccases: Some Recent Advances and Applications
    (Springer Nature , 2020) Martins, Ligia O.; Pinho Melo, Eduardo; Sánchez Amat, Antonio; Robalo, Maria Paula; Genética y Microbiología
    Laccases belong to the large family of multi-copper oxidases (MCOs) that couple the one-electron oxidation of substrates with the four-electron reduction of molecular oxygen to water. Because of their high relative non-specific oxidation capacity particularly on phenols and aromatic amines as well as the lack of requirement for expensive organic cofactors, they have found application in a large number of biotechnological fields. The vast majority of studies and applications were performed using fungal laccases, but bacterial laccases show interesting properties such as optimal temperature above 50 ºC, optimal pH at the neutral to alkaline range, thermal and chemical stability and increased salt tolerance. Additionally, bacterial systems benefit from a wide range of molecular biology tools that facilitates their engineering and achievement of high yields of protein production and set-up of costeffective bioprocesses. In this review we will provide up-to-date information on the distribution and putative physiological role of bacterial laccases and highlight their distinctive structural and biochemical properties, discuss the key role of copper in the biochemical properties, discuss thermostability determinants and, finally, review biotechnological applications with a focus on catalytic mechanisms on phenolics and aromatic amines.
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    Characterization of PlGoxB, a flavoprotein required for cysteine tryptophylquinone biosynthesis in glycine oxidase from Pseudoalteromonas luteoviolacea
    (Elsevier BV, 2019-09-17) Mamounis, Kyle J.; Ma, Zhongxin; Sanchez-Amat, Antonio; Davidson, Victor L.; Genética y Microbiología
    LodA-like proteins are oxidases with a protein-derived cysteine tryptophylquinone (CTQ) prosthetic group. In Pseudoalteromonas luteoviolacea glycine oxidase (PlGoxA), CTQ biosynthesis requires post-translational modifications catalyzed by a modifying enzyme encoded by PlgoxB. The PlGoxB protein was expressed and shown to possess a flavin cofactor. PlGoxB was unstable in solution as it readily lost the flavin and precipitated. PlGoxB precipitation was significantly reduced by incubation with either excess FAD or an equal concentration of prePlGoxA, the precursor protein that is its substrate. In contrast, the mature CTQ-bearing PlGoxA had no stabilizing effect. A homology model of PlGoxB was generated using the structure of Alkylhalidase CmIS. The FAD-binding site of PlGoxB in the model was nearly identical to that of the template structure. The bound FAD in PlGoxB had significant solvent exposure, consistent with the observed tendency to lose FAD. This also suggested that interaction of prePlGoxA with PlGoxB at the exposed FAD-binding site could prevent the observed loss of FAD and subsequent precipitation of PlGoxB. A docking model of the putative PlGoxB-prePlGoxA complex was consistent with these hypotheses. The experimental results and computational analysis implicate structural features of PlGoxB that contribute to its stability and function.