Browsing by Subject "Microbiology"

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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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    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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    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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    Broccoli and Radish Sprouts are Safe and Rich in Bioactive Phytochemicals
    (Elsevier, ) Baenas, Nieves; Gómez-Jodar, Isabel; Moreno, Diego A.; García-Viguera, Cristina; Periago, Paula M.; Tecnología de Alimentos, Nutrición y Bromatología
    Cruciferous sprouts (e.g. broccoli and red radish) are rich source of health-promoting phytochemicals more concentrated than the adult plant edible organs; however, these tiny microgreens need cold storage conditions to preserve their quality to reach the consumers in microbiologically safe conditions, maintaining their composition and acceptability. In this work, the microbiological status and phytochemical composition of broccoli and radish sprouts were evaluated at harvest (Day 0), and after seven and fourteen days of storage at two different temperatures, 5 and 10 °C. Pathogenic microorganisms were absent during shelf-life; nevertheless, the slight growth of Enterobacteriaceae organisms, aerobic mesophilic and psychrotrophic bacteria, molds and yeasts was assessed. The temperature of storage highly influenced the quality and content of bioactives in the sprouts, and for practical applications, the storage at 5 ºC is the most suitable option. Moreover, these fresh crucifers remain acceptable for consumers after a long refrigerated storage period (14 d), being an interesting option for consuming fresh and naturally-functional foods.
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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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    Distribution of airborne pollen, fungi and bacteria at four altitudes using high-throughput DNA sequencing
    (Elsevier, 2020-10-11) Sánchez-Parra, Beatriz; Núñez, Andrés; García, Ana M.; Campoy, Pascual; Moreno, Diego A.; Genética y Microbiología
    The diversity and composition of bioaerosols in the atmosphere have been studied in the recent years in multiple places and under very different meteorological conditions. Pollen grains, fungal propagules and bacteria are the most studied airborne biological particles, usually individually, and correlated to environmental factors such as temperature, wind speed, rain, air pollution, etc. to understand their influence. However, the effect of the height on the distribution and composition of these bioaerosols has not been properly described so far. In this research, we analyzed concurrently these three biological particles at four different heights (1.5 m, 130 m, 500 m and 1000 m) by high-throughput DNA sequencing. We observed that the atmosphere contains a homogeneous distribution and composition of biological particles regardless of the altitude tested. Only a minority of the taxa is differently distributed. Therefore, we here deduce that the altitude does not drastically influence the airborne bioparticles distribution and composition under similar meteorological conditions. We also studied the co-occurrence between different bioaerosols, finding new potential relationships.
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    Effect of the passive natural ventilation on the bioaerosol in a small room
    (Elsevier, 2021-10-13) Núñez, Andrés; García, Ana M.; Genética y Microbiología
    Natural passive ventilation (windows opening) is frequently used in many houses and old buildings to renovate the air, remove unpleasant odors and dust, and reduce the physicochemical pollutants indoor. However, little is known about the effect on biological particles such as pollen grains and fungal spores (both allergenic) or bacteria (potentially infectious and pathogenic). In the present research, the bioaerosols composition in a small room naturally ventilated was analyzed by high-throughput DNA sequencing. Pollen grains were the most abundant particles outdoors while microbial phyla Actinobacteria, Firmicutes, Proteobacteria and Ascomycota were predominant indoors. The main divergences in bioaerosols between indoor and outdoor environments were caused by the different abundance of the biological particles rather than the different taxa composition. Keeping the window open for 2 h did not change significantly the microbial community present indoors, although there was a tendency to mix the components of both environments. The abundance of human-related and potentially harmful microorganisms was higher indoors and was not remarkably affected by natural ventilation. In our study, natural ventilation through window opening had a poor effect on removing these microorganisms from the atmosphere indoor, suggesting that additional mechanisms such as air filtering systems would be required in order to improve the air quality of these environments from a microbiological point of view.
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    Fission Yeast Receptor of Activated C Kinase (RACK1) Ortholog Cpc2 Regulates Mitotic Commitment through Wee1 Kinase
    (American Society for Biochemistry and Molecular Biology, 2010-10-25) Núñez, Andrés; Franco, Alejandro; Soto, Teresa; Vicente, Jero; Cansado Vizoso, José; Genética y Microbiología
    In the fission yeast Schizosaccharomyces pombe, Wee1-dependent inhibitory phosphorylation of the highly conserved Cdc2/Cdk1 kinase determines the mitotic onset when cells have reached a defined size. The receptor of activated C kinase (RACK1) is a scaffolding protein strongly conserved among eukaryotes which binds to other proteins to regulate multiple processes in mammalian cells, including the modulation of cell cycle progression during G1/S transition. We have recently described that Cpc2, the fission yeast ortholog to RACK1, controls from the ribosome the activation of MAPK cascades and the cellular defense against oxidative stress by positively regulating the translation of specific genes whose products participate in the above processes. Intriguingly, mutants lacking Cpc2 display an increased cell size at division, suggesting the existence of a specific cell cycle defect at the G2/M transition. In this work we show that protein levels of Wee1 mitotic inhibitor are increased in cells devoid of Cpc2, whereas the levels of Cdr2, a Wee1 inhibitor, are down-regulated in the above mutant. On the contrary, the kinetics of G1/S transition was virtually identical both in control and Cpc2-less strains. Thus, our results suggest that in fission yeast Cpc2/RACK1 positively regulates from the ribosome the mitotic onset by modulating both the protein levels and the activity of Wee1. This novel mechanism of translational control of cell cycle progression might be conserved in higher eukaryotes.
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    Incidence and predictors of sternal surgical wound infection in cardiac surgery: a prospective study
    (Wiley, 2022-09-28) Arribas Leal, José María; Rivera Caravaca, José Miguel; Hernández Torres, Alicia; Jiménez Aceituna, Antonio; Moral Escudero, Encarnación; Pérez Andreu, Joaquín; García Vázquez, Elisa; Gutiérrez García, Francisco; García Puente, Julio J.; Marín, Francisco; Cánovas López, Sergio; Herrero Martínez, José Antonio; Cirugía, Pediatría y Obstetricia y Ginecología
    Sternal surgical wound infection (SSWI) in cardiac surgery is associated with increased morbidity. We investigated the incidence of SSWI, the main germs implicated and predictors of SSWI. Prospective study including patients undergoing full median sternotomy between January 2017 and December 2019. Patients were followed-up for 3 months after hospital discharge. All sternal wound infections up to 90 days after discharge were considered SSWI. 1004 patients were included. During follow-up, 68 (6.8%) patients presented SSWI. Patients with SSWI had a higher incidence of postoperative renal failure (29.4% vs 17.1%, P = .007), a higher incidence of early postoperative reoperation for non-infectious causes (42.6% vs 9.1%, P < .001), longer ICU stay (3 [2–9] days vs 2 [2–4] days, P = .006), and longer hospital stay (24.5 [14.8–38.3] days vs 10 [7–18] days, P < .001). Gram-positive germs were presented in 49% of the cultures, and gram-negative bacteria in 35%. Early reoperation for non-infectious causes (OR 4.90, 95% CI 1.03–23.7), and a longer ICU stay (OR 1.37 95% CI 1.10–1.72) were independent predictors of SSWI. SSWI is rare but leads to more postoperative complications. The need for early reoperation because of non-infectious cause and a longer ICU stay were independently associated with SSWI.
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    Light-induced rhythmic changes in thermotolerance in stationary-phase cells of Candida utilis
    (International microbiology : the official journal of the Spanish Society for Microbiology., 2006) Lapeña, Miguel A.; Vicente, Jero; Soto, Teresa; Madrid, Marisa; Núñez, Andrés; García, Encarnación; Cansado Vizoso, José; Gacto, Mariano; Genética y Microbiología
    In synchronized light-dark cycles, stationary-phase cultures of the budding yeast Candida utilis were able to survive heat treatment at 50ºC with an apparent circadian-like rhythm related to the onset of light. However, in continuous darkness this pattern did not run freely and was markedly dampened. We discuss these findings in terms of the potential circadian control of heat tolerance, which has been described in the fission yeast Schizosaccharomyces pombe. Our results suggest that the resistance pattern observed in C. utilis is most likely an adaptive response to the light-induced generation of reactive oxygen species rather than the occurrence of a truly endogenous circadian rhythm
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    Microcystin influence on soil-plant microbiota: unraveling microbiota modulations and assembly processes in the rhizosphere of Vicia faba
    (Elsevier, 2024-02-06) Redouane, El Mahdi; Núñez, Andrés; Achouak, Wafa; Barakat, Mohamed; Alex, Anoop; Martins, José Carlos; Tazart, Zakaria; Mugani, Richard; Zerrifi, Soukaina El Amrani; Haida, Mohammed; García, Ana M.; Campos, Alexandre; Lahrouni, Majida; Oufdou, Khalid; Vasconcelos, Vitor; Oudra, Brahim; Genética y Microbiología
    Microcystins (MCs) are frequently detected in cyanobacterial bloom-impacted waterbodies and introduced into agroecosystems via irrigation water. They are widely known as phytotoxic cyanotoxins, which impair the growth and physiological functions of crop plants. However, their impact on the plant-associated microbiota is scarcely tackled and poorly understood. Therefore, we aimed to investigate the effect of MCs on microbiota-inhabiting bulk soil (BS), root adhering soil (RAS), and root tissue (RT) of Vicia faba when exposed to 100 μg L−1 MCs in a greenhouse pot experiment. Under MC exposure, the structure, co-occurrence network, and assembly processes of the bacterial microbiota were modulated with the greatest impact on RT-inhabiting bacteria, followed by BS and, to a lesser extent, RAS. The analyses revealed a significant decrease in the abundances of several Actinobacteriota-related taxa within the RT microbiota, including the most abundant and known genus of Streptomyces. Furthermore, MCs significantly increased the abundance of methylotrophic bacteria (Methylobacillus, Methylotenera) and other Proteobacteria-affiliated genera (e.g., Paucibacter), which are supposed to degrade MCs. The co-occurrence network of the bacterial community in the presence of MCs was less complex than the control network. In MC-exposed RT, the turnover in community composition was more strongly driven by deterministic processes, as proven by the beta-nearest taxon index. Whereas in MC-treated BS and RAS, both deterministic and stochastic processes can influence community assembly to some extent, with a relative dominance of deterministic processes. Altogether, these results suggest that MCs may reshape the structure of the microbiota in the soil-plant system by reducing bacterial taxa with potential phytobeneficial traits and increasing other taxa with the potential capacity to degrade MCs.
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    Monitoring of airborne biological particles in outdoor atmosphere. Part 1: Importance, variability and ratios
    (Hemeroteca Científica Catalana [University Publisher], 2016-03-10) Núñez, Andrés; Amo de Paz, Guillermo; Rastrojo, Alberto; García, Ana M.; Alcamí, Antonio; Gutiérrez-Bustillo, A. Montserrat; Moreno, Diego A.; Genética y Microbiología
    The first part of this review ("Monitoring of airborne biological particles in outdoor atmosphere. Part 1: Importance, variability and ratios") describes the current knowledge on the major biological particles present in the air regarding their global distribution, concentrations, ratios and influence of meteorological factors in an attempt to provide a framework for monitoring their biodiversity and variability in such a singular environment as the atmosphere. Viruses, bacteria, fungi, pollen and fragments thereof are the most abundant microscopic biological particles in the air outdoors. Some of them can cause allergy and severe diseases in humans, other animals and plants, with the subsequent economic impact. Despite the harsh conditions, they can be found from land and sea surfaces to beyond the troposphere and have been proposed to play a role also in weather conditions and climate change by acting as nucleation particles and inducing water vapour condensation. In regards to their global distribution, marine environments act mostly as a source for bacteria while continents additionally provide fungal and pollen elements. Within terrestrial environments, their abundances and diversity seem to be influenced by the land-use type (rural, urban, coastal) and their particularities. Temporal variability has been observed for all these organisms, mostly triggered by global changes in temperature, relative humidity, et cetera. Local fluctuations in meteorological factors may also result in pronounced changes in the airbiota. Although biological particles can be transported several hundreds of meters from the original source, and even intercontinentally, the time and final distance travelled are strongly influenced by factors such as wind speed and direction.
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    Monitoring of airborne biological particles in outdoor atmosphere. Part 2: metagenomics applied to urban environments
    (Institut d'Estudis Catalans, 2016-11-15) Núñez, Andrés; Amo de Paz, Guillermo; Rastrojo, Alberto; García, Ana M.; Alcamí, Antonio; Gutiérrez-Bustillo, A. Montserrat; Moreno, Diego A.; Genética y Microbiología
    The air we breathe contains microscopic biological particles such as viruses, bacteria, fungi and pollen, some of them with relevant clinic importance. These organisms and/or their propagules have been traditionally studied by different disciplines and diverse methodologies like culture and microscopy. These techniques require time, expertise and also have some important biases. As a consequence, our knowledge on the total diversity and the relationships between the different biological entities present in the air is far from being complete. Currently, metagenomics and next-generation sequencing (NGS) may resolve this shortage of information and have been recently applied to metropolitan areas. Although the procedures and methods are not totally standardized yet, the first studies from urban air samples confirm the previous results obtained by culture and microscopy regarding abundance and variation of these biological particles. However, DNA-sequence analyses call into question some preceding ideas and also provide new interesting insights into diversity and their spatial distribution inside the cities. Here, we review the procedures, results and perspectives of the recent works that apply NGS to study the main biological particles present in the air of urban environments.
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    Perspectivas Educativas en Microbiología: Análisis del Impacto de las Prácticas Virtuales vs las Prácticas Presenciales en Alumnos del Grado de Podología
    (Universidad de Murcia. Servicio de publicaciones, 2024) González Hidalgo, Natalia; Gómez Lus Centelles, María Luisa; Sevillano Fernández, David; Alou Cervera, Luis
    Con el objetivo de integrar de manera efectiva los entornos virtuales en las prácticas deMicrobiología, se ha analizado la eficacia de las prácticas en formato virtual en comparación con elpresencial en la asignatura de Microbiología del Grado de Podología. Tras elegir el formato prácticopresencial o virtual, los alumnos realizaron voluntariamente cuestionarios de conocimientosprevios y posteriores a las prácticas, con el fin de evaluar su rendimiento. Asimismo, se evaluó elcompromiso y satisfacción de los estudiantes. La mayoría de los alumnos eligieron realizar las prácticas en formato presencial, mostrando un mayor compromiso y participación en los cuestionarios. Ambos grupos experimentaron una mejora en el rendimiento, sin diferencias significativas entre formatos. Los estudiantes que participaron en las prácticas expresaron un alto nivel de satisfacción en ambos formatos. Las prácticas virtuales suponen una alternativa adecuada alas prácticas presenciales en la enseñanza de Microbiología.
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    Preventing legionellosis outbreaks by a quick detection of airborne Legionella pneumophila
    (Elsevier, 2019-01-15) Sánchez-Parra, Beatriz; Núñez, Andrés; Moreno, Diego A.; Genética y Microbiología
    Legionellosis is a severe pneumonic infection caused by inhaling bacteria of the genus Legionella. Most cases reported in the USA and Europe are associated with the species Legionella pneumophila. This Gram-negative bacterium can survive within a wide spectrum of temperatures, and be transmitted via aerosols from multiple aquatic sources: fountains, thermal spas and other water systems. Although the PCR is one of the most popular methods to verify its presence in environmental or clinical samples, the direct application of this technique to ambient air samples is unusual because of the scarce material in the specimens. Here, we have developed a two-PCR assay, carried out over the V3 and V5 hypervariable regions of the 16S rRNA gene, to detect specifically the pathogenic bacteria Legionella pneumophila in outdoor air samples with low concentration of DNA. The application of this protocol does not require culture and retrieves quick results to activate the corresponding public alerts to prevent legionellosis outbreaks.
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    Saharan dust storms affecting the center of the Iberian Peninsula: effect on the urban aerobiome
    (Elsevier, 2024-04-16) Núñez, Andrés; Moreno, Diego A.; García, Ana M.; Genética y Microbiología
    Dust storms are known to be atmospheric phenomena that transport mineral dust but also airborne biological particles (bioaerosols) from desert areas to distant regions. These bioaerosols can influence atmospheric processes and they have the potential of changing the composition of the local aerobiome in urban areas, which, in recent years, have been associated with allergies and the exacerbation of respiratory syndromes. Here, we studied four dust events initiated in the Sahara Desert affecting the center of the Iberian Peninsula. The biological particles before and during the phenomena were analyzed by high-throughput DNA sequencing. The global composition of bioaerosols showed a marked seasonality. The relative abundances of the most predominant groups of bacteria and fungi were not significantly altered compared to the days prior the corresponding event. Nonetheless, we detected specific bacterial and fungal taxa associated with these events, whose composition and abundance were also related to the period of the year. Although a variety of plant and animal pathogens were identified both before and throughout the days influenced by dust storms, some were only detected during the latter, suggesting a long-range transport for these species. This work highlights the importance of analyzing the storm dust events separately, especially when they occur at different seasons, and the particular effect on an urban environment in the Iberian Peninsula as a model case, providing some recommendations for future studies.
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    Seasonal changes dominate long-term variability of the urban air microbiome across space and time
    (Elsevier, 2021-02-09) Núñez, Andrés; García, Ana M.; Moreno, Diego A.; Guantes, Raúl; Genética y Microbiología
    Compared to soil or aquatic ecosystems, the atmosphere is still an underexplored environment for microbial diversity. In this study, we surveyed the composition, variability and sources of microbes (bacteria and fungi) in the near surface atmosphere of a highly populated area, spanning ~ 4,000 Km2 around the city center of Madrid (Spain), in different seasonal periods along two years. We found a core of abundant bacterial genera robust across space and time, most of soil origin, while fungi were more sensitive to environmental conditions. Microbial communities showed clear seasonal patterns driven by variability of environmental factors, mainly temperature and accumulated rain, while local sources played a minor role. We also identified taxa in both groups characteristic of seasonal periods, but not of specific sampling sites or plant coverage. The present study suggests that the near surface atmosphere of urban environments contains an ecosystem stable across relatively large spatial and temporal scales, with a rather homogenous composition, modulated by climatic variations. As such, it contributes to our understanding of the long-term changes associated to the human exposome in the air of highly populated areas.
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    Stress-activated MAPK signaling controls fission yeast actomyosin ring integrity by modulating formin For3 levels
    (ELIFE SCIENCES PUBLICATIONS LTD, 2020-09-11) Gómez-Gil, E.; Martín-García, R.; Vicente-Soler, J.; Franco, A.; Vázquez-Marín, B.; Prieto-Ruiz, F.; Soto, T.; Pérez, P.; Madrid, M.; Cansado Vizoso, José; Genética y Microbiología
    Cytokinesis, which enables the physical separation of daughter cells once mitosis has been completed, is executed in fungal and animal cells by a contractile actin- and myosin-based ring (CAR). In the fission yeast Schizosaccharomyces pombe, the formin For3 nucleates actin cables and also co-operates for CAR assembly during cytokinesis. Mitogen-activated protein kinases (MAPKs) regulate essential adaptive responses in eukaryotic organisms to environmental changes. We show that the stress-activated protein kinase pathway (SAPK) and its effector, MAPK Sty1, downregulates CAR assembly in S. pombe when its integrity becomes compromised during cytoskeletal damage and stress by reducing For3 levels. Accurate control of For3 levels by the SAPK pathway may thus represent a novel regulatory mechanism of cytokinesis outcome in response to environmental cues. Conversely, SAPK signaling favors CAR assembly and integrity in its close relative Schizosaccharomyces japonicus, revealing a remarkable evolutionary divergence of this response within the fission yeast clade.
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    Temporal patterns of variability for prokaryotic and eukaryotic diversity in the urban air of Madrid (Spain)
    (Elsevier, 2019-09-10) Núñez, Andrés; Amo de Paz, Guillermo; Rastrojo, Alberto; Ferencova, Zuzana; Gutiérrez-Bustillo, A. Montserrat; Alcamí, Antonio; Moreno, Diego A.; Guantes, Raúl; Genética y Microbiología
    Although many microorganisms are ubiquitously present in the air, airborne microbial communities have been much less characterized than those in soil or aquatic environments. Besides its ecological importance, detection and monitoring of the wide diversity of these aerosolized microorganisms (bacteria, viruses, fungi and pollen) is relevant for understanding allergy and disease outbreaks, especially in highly populated cities. In this study, we describe the simultaneous biodiversity of bacteria, fungi and plants present in the urban atmosphere of Madrid (Spain) along different seasonal periods, using DNA sequencing. Sampling in two different locations (downtown and peri-urban) we found that changes in the composition of each community are mainly driven by environmental factors, rather than by the features of the specific sampling microenvironments. While pollen particles are dominated by a few taxa characteristic of each season, bacteria and fungi show a high diversity but stable core communities along the year. The prokaryotic core is governed by soil and leaf surface bacteria, with predominance of Actinobacteria (Frankiales and Micrococcales) and Alphaproteobacteria (Sphingomonadales, Rhodobacterales, Rhizobiales and Acetobacterales). Fungal diversity is characterized by the steady presence of members of Capnodiales and Pleosporales. Pathogenic bacterial and fungal taxa were also detected across the year. We also correlated the airborne biodiversity with environmental variables. Air temperature has a strong influence on the community composition of bacteria, while pollen and fungi seasonal variations are mainly correlated with precipitation. Our results contribute to the characterization of airborne prokaryotic and eukaryotic communities in urban areas and show the suitability of this method for biosurveillance strategies.