Linking Uncultivated Microbial Populations and Benthic Carbon Turnover by Using Quantitative Stable Isotope Probing

Benthic environments harbor highly diverse and complex microbial communities that control carbon fluxes, but the role of specific uncultivated microbial groups in organic matter turnover is poorly understood. In this study, quantitative DNA stable isotope probing (DNA-qSIP) was used for the first time to link uncultivated populations of bacteria and archaea to carbon turnover in lacustrine surface sediments. After 1-week incubations in the dark with [C-13]bicarbonate, DNA-qSIP showed that ammoniaoxidizing archaea (AOA) were the dominant active chemolithoautotrophs involved in the production of new organic matter. Natural C-13-labeled organic matter was then obtained by incubating sediments in the dark for 2.5 months with [C-13] bicarbonate, followed by extraction and concentration of high-molecular-weight (HMW) (> 50-kDa) organic matter. qSIP showed that the labeled organic matter was turned over within 1 week by 823 microbial populations (operational taxonomic units [OTUs]) affiliated primarily with heterotrophic Proteobacteria, Chloroflexi, Verrucomicrobia, and Bacteroidetes. However, several OTUs affiliated with the candidate microbial taxa Latescibacteria, Omnitrophica, Aminicentantes, Cloacimonates, AC1, Bathyarchaeota, and Woesearchaeota, groups known only from genomic signatures, also contributed to biomass turnover. Of these 823 labeled OTUs, 52% (primarily affiliated with Proteobacteria) also became labeled in 1-week incubations with [C-13] bicarbonate, indicating that they turned over carbon faster than OTUs that were labeled only in incubations with C-13-labeled HMW organic matter. These taxa consisted primarily of uncultivated populations within the Firmicutes, Bacteroidetes, Verrucomicrobia, and Chloroflexi, highlighting their ecological importance. Our study helps define the role of several poorly understood, uncultivated microbial groups in the turnover of benthic carbon derived from "dark" primary production. IMPORTANCE Little is known about the ecological role of uncultivated microbial populations in carbon turnover in benthic environments. To better understand this, we used quantitative stable isotope probing (qSIP) to quantify the abundance of diverse, specific groups of uncultivated bacteria and archaea involved in autotrophy and heterotrophy in a benthic lacustrine habitat. Our results provide quantitative evidence for active heterotrophic and autotrophic metabolism of several poorly understood microbial groups, thus demonstrating their relevance for carbon turnover in benthic settings. Archaeal ammonia oxidizers were significant drivers of in situ "dark" primary production supporting the growth of heterotrophic bacteria. These findings expand our understanding of the microbial populations within benthic food webs and the role of uncultivated microbes in benthic carbon turnover

Development of Functional Microfold (M) Cells from Intestinal Stem Cells in Primary Human Enteroids.

Background & aimsIntestinal microfold (M) cells are specialized epithelial cells that act as gatekeepers of luminal antigens in the intestinal tract. They play a critical role in the intestinal mucosal immune response through transport of viruses, bacteria and other particles and antigens across the epithelium to immune cells within Peyer's patch regions and other mucosal sites. Recent studies in mice have demonstrated that M cells are generated from Lgr5+ intestinal stem cells (ISCs), and that infection with Salmonella enterica serovar Typhimurium increases M cell formation. However, it is not known whether and how these findings apply to primary human small intestinal epithelium propagated in an in vitro setting.MethodsHuman intestinal crypts were grown as monolayers with growth factors and treated with recombinant RANKL, and assessed for mRNA transcripts, immunofluorescence and uptake of microparticles and S. Typhimurium.ResultsFunctional M cells were generated by short-term culture of freshly isolated human intestinal crypts in a dose- and time-dependent fashion. RANKL stimulation of the monolayer cultures caused dramatic induction of the M cell-specific markers, SPIB, and Glycoprotein-2 (GP2) in a process primed by canonical WNT signaling. Confocal microscopy demonstrated a pseudopod phenotype of GP2-positive M cells that preferentially take up microparticles. Furthermore, infection of the M cell-enriched cultures with the M cell-tropic enteric pathogen, S. Typhimurium, led to preferential association of the bacteria with M cells, particularly at lower inoculum sizes. Larger inocula caused rapid induction of M cells.ConclusionsHuman intestinal crypts containing ISCs can be cultured and differentiate into an epithelial layer with functional M cells with characteristic morphological and functional properties. This study is the first to demonstrate that M cells can be induced to form from primary human intestinal epithelium, and that S. Typhimurium preferentially infect these cells in an in vitro setting. We anticipate that this model can be used to generate large numbers of M cells for further functional studies of these key cells of intestinal immune induction and their impact on controlling enteric pathogens and the intestinal microbiome

Sero-Epidemiology of Pneumocystis Infection among Infants, Children, and Adults in Chile

Previous serologic surveys show >80% of infants in Chile have anti-Pneumocystis antibodies by 2 years of age, but the seroepidemiology of Pneumocystis infection beyond infancy is unknown. We describe the sero-epidemiology in infants, children, and adults at different locations in Chile. Serum samples were prospectively obtained from 681 healthy adults (age ≥ 17 years) and 690 non-immunocompromised infants/children attending eight blood banks or outpatient clinics (2 in Santiago) in Chile. ELISA was used to measure serum IgM and IgG antibodies to Pneumocystis jirovecii major surface antigen (Msg) constructs MsgA and MsgC1. Serologic responses to Pneumocystis Msg showed a high frequency of reactivity, inferring infection. Among infants/children increasing age and the proportion with detectable IgM responses to MsgA, and IgG responses to MsgA, and MsgC1 were positively associated. Among adults there was almost universal seropositivity to one or more Pneumocystis Msg constructs. In infants and children rates of detectable IgM responses to MsgC1 and MsgA were greater than IgG responses. In Santiago, rates of seropositivity among infants/children were greater in clinics located in a more socio-economically deprived part of the city. In Chile, a serological response to Pneumocystis Msg constructs was common across ages regardless of geographical location and climatic conditions. Observed higher rates of IgM responses than IgG responses is consistent with concept of recent/ongoing exposure to Pneumocystis in children and adults. Higher rates of seropositivity in infants/children residing in more densely populated areas of Santiago infers crowding poses an increased risk of transmission

Atribacteria reproducing over millions of years in the Atlantic abyssal subseafloor

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Vuillemin, A., Vargas, S., Coskun, O. K., Pockalny, R., Murray, R. W., Smith, D. C., D'Hondt, S., & Orsi, W. D. Atribacteria reproducing over millions of years in the Atlantic abyssal subseafloor. Mbio, 11(5), (2020): e01937-20, doi:10.1128/mBio.01937-20.How microbial metabolism is translated into cellular reproduction under energy-limited settings below the seafloor over long timescales is poorly understood. Here, we show that microbial abundance increases an order of magnitude over a 5 million-year-long sequence in anoxic subseafloor clay of the abyssal North Atlantic Ocean. This increase in biomass correlated with an increased number of transcribed protein-encoding genes that included those involved in cytokinesis, demonstrating that active microbial reproduction outpaces cell death in these ancient sediments. Metagenomes, metatranscriptomes, and 16S rRNA gene sequencing all show that the actively reproducing community was dominated by the candidate phylum “Candidatus Atribacteria,” which exhibited patterns of gene expression consistent with fermentative, and potentially acetogenic, metabolism. “Ca. Atribacteria” dominated throughout the 8 million-year-old cored sequence, despite the detection limit for gene expression being reached in 5 million-year-old sediments. The subseafloor reproducing “Ca. Atribacteria” also expressed genes encoding a bacterial microcompartment that has potential to assist in secondary fermentation by recycling aldehydes and, thereby, harness additional power to reduce ferredoxin and NAD+. Expression of genes encoding the Rnf complex for generation of chemiosmotic ATP synthesis were also detected from the subseafloor “Ca. Atribacteria,” as well as the Wood-Ljungdahl pathway that could potentially have an anabolic or catabolic function. The correlation of this metabolism with cytokinesis gene expression and a net increase in biomass over the million-year-old sampled interval indicates that the “Ca. Atribacteria” can perform the necessary catabolic and anabolic functions necessary for cellular reproduction, even under energy limitation in millions-of-years-old anoxic sediments.This work was supported primarily by the Deutsche Forschungsgemeinschaft (DFG) project OR 417/1-1 granted to W.D.O. Preliminary work was supported by the Center for Dark Energy Biosphere Investigations project OCE-0939564 also granted to W.D.O. The expedition was funded by the US National Science Foundation through grant NSF-OCE-1433150 to S.D. and R.P. R.W.M. led the expedition. Shipboard microbiology efforts were supported by the Center for Dark Energy Biosphere Investigations (C-DEBI grant NSF-OCE-0939564). This is C-DEBI publication 545. This is a contribution of the Deep Carbon Observatory (DCO)

Energy loss of protons and deuterons at low energies in Pd polycrystalline thin films

We have investigated experimentally and by computer simulations the energy loss  distributions of low energy (E <10 keV) protons and deuterons transmitted through  polycrystalline palladium thin flms. In contrast with previous experiments on various transition metals we find that the stopping power of Pd is proportional to the ion velocity. Data of protons and deuterons are coincident within the experimental uncertainties, showing the absence of an isotopic effect on the stopping power of Pd in this energy range. The experimental results were analyzed and compared with Monte Carlo computer simulations and previous theoretical models. The dference in the velocity dependence of the energy loss of hydrogen ions in Pd with respect to other transition metals (Cu, Ag and Au) is explained by a theoretical analysis based on the properties of the d-electron bands of those elements.Fil: Celedón, C.. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); ArgentinaFil: Sanchez, Esteban Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Moreno, Mario Sergio Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Arista, Nestor Ricardo. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Uribe, J. D.. Universidad Técnica Federico Santa María. Departamento de Física. Laboratorio de Colisiones Atómicas; ChileFil: Mery, M.. Universidad Técnica Federico Santa María. Departamento de Física. Laboratorio de Colisiones Atómicas; ChileFil: Valdés, J. E.. Universidad Técnica Federico Santa María. Departamento de Física. Laboratorio de Colisiones Atómicas; ChileFil: Vargas, P.. Universidad Técnica Federico Santa María. Departamento de Física. Laboratorio de Colisiones Atómicas; Chil

Summer truffle in the Iberian Peninsula: current status and crop potential

La trufa de verano (Tuber aestivum, incluyendo Tuber uncinatum) es una especie de un gran valor económico y social, que se produce de modo silvestre en toda Europa, norte de África y parte de Oriente medio. Los esfuerzos de cultivo de esta especie en la península ibérica han permanecido en un segundo plano debido a las condiciones adecuadas de ciertos terrenos para cultivar especies de mayor valor económico, como la trufa negra (Tuber melanosporum). Sin embargo, la trufa de verano es una alternativa viable y muy productiva para zonas de dudosa aptitud para T. melanosporum. En este trabajo, mediante revisión bibliográfica, se ponen de manifiesto los siguientes aspectos: la distribución y ecología de T. aestivum, la situación actual del cultivo, así como las perspectivas de futuro propias de esta especie en la península ibérica. En rasgos generales, se ha constatado su mayor amplitud ecológica y geográfica en relación a la trufa negra y se ha observado que es un cultivo incipiente pero en crecimiento. Sin embargo, se ha deducido que aún es necesario realizar un gran esfuerzo para dar a conocer este producto tanto a cultivadores como a consumidores potenciales en España así como divulgar aspectos técnicos sobre la gestión de su cultivo.Summer truffle (Tuber aestivum, including Tuber uncinatum) is a species of great economic and social value. Wild summer truffles are produced all over Europe, North Africa and part of the Middle East. This species has been underutilized in the Iberian Peninsula due to ability of certain areas to cultivate species of greater economic value, such as the black truffle (Tuber melanosporum). However, the summer truffle is an alternative species for areas where the black truffle is not well adapted. In this paper, the distribution and ecology of T. aestivum, the current situation and the future prospects of this crop in the Iberian Peninsula is reviewed. Summer truffle is a growing crop, well adapted in greater ecological and geographical areas than black truffle. However, it is still necessary to carry out further efforts to publicize it to both growers and consumers in Spain and to spread technical aspects of its managementPublishe

Archaea dominate oxic subseafloor communities over multimillion-year time scales

Ammonia-oxidizing archaea (AOA) dominate microbial communities throughout oxic subseafloor sediment deposited over millions of years in the North Atlantic Ocean. Rates of nitrification correlated with the abundance of these dominant AOA populations, whose metabolism is characterized by ammonia oxidation, mixotrophic utilization of organic nitrogen, deamination, and the energetically efficient chemolithoautotrophic hydroxypropionate/hydroxybutyrate carbon fixation cycle. These AOA thus have the potential to couple mixotrophic and chemolithoautotrophic metabolism via mixotrophic deamination of organic nitrogen, followed by oxidation of the regenerated ammonia for additional energy to fuel carbon fixation. This metabolic feature likely reduces energy loss and improves AOA fitness under energy-starved, oxic conditions, thereby allowing them to outcompete other taxa for millions of years

Las representaciones gráficas en la formación de alumnos de la carrera de arquitectura de la FAU-UNNE-Arquitectura IV-UPC

El objetivo del presente trabajo es exponer los resultados preliminares del Proyecto de Investigación 12C006-2013-16 “Las Representaciones Gráficas en la Formación de Alumnos de la Carrera de Arquitectura-UNNE” que estamos desarrollando para conocer la manera en que los alumnos de Arquitectura de nuestra Universidad representan el objeto arquitectónico con métodos analógicos y digitales en la actualidad. Los resultados permitirán expresar el impacto del mundo digital sobre las representaciones, permitirán conocer las habilidades y destrezas del estudiante en relación a los Sistemas de Representación a través de cortes transversales en cinco (5) momentos de la formación en la carrera de Arquitectura (nivel ingresantes, primero, segundo, cuarto y sexto años) en los ciclos lectivos 2013 a 2016. Se propone una investigación cualitativa, descriptiva-explicativa que permita identificar y conocer las distintas maneras en que los alumnos prefiguran y construyen sus imágenes arquitectónicas. Fundamentalmente nos explayamos en la experiencia del Taller Virtual Red Norte Grande, experiencia innovadora única del taller colaborativo en la Cátedra Arquitectura IV UPC.Área temática 5: Comunicación y Sistemas de Representación - Eje InvestigaciónFacultad de Arquitectura y Urbanism

Las representaciones gráficas en la formación de alumnos de la carrera de arquitectura de la FAU-UNNE-Arquitectura IV-UPC

El objetivo del presente trabajo es exponer los resultados preliminares del Proyecto de Investigación 12C006-2013-16 “Las Representaciones Gráficas en la Formación de Alumnos de la Carrera de Arquitectura-UNNE” que estamos desarrollando para conocer la manera en que los alumnos de Arquitectura de nuestra Universidad representan el objeto arquitectónico con métodos analógicos y digitales en la actualidad. Los resultados permitirán expresar el impacto del mundo digital sobre las representaciones, permitirán conocer las habilidades y destrezas del estudiante en relación a los Sistemas de Representación a través de cortes transversales en cinco (5) momentos de la formación en la carrera de Arquitectura (nivel ingresantes, primero, segundo, cuarto y sexto años) en los ciclos lectivos 2013 a 2016. Se propone una investigación cualitativa, descriptiva-explicativa que permita identificar y conocer las distintas maneras en que los alumnos prefiguran y construyen sus imágenes arquitectónicas. Fundamentalmente nos explayamos en la experiencia del Taller Virtual Red Norte Grande, experiencia innovadora única del taller colaborativo en la Cátedra Arquitectura IV UPC.Área temática 5: Comunicación y Sistemas de Representación - Eje InvestigaciónFacultad de Arquitectura y Urbanism

Las representaciones gráficas en la formación de alumnos de la carrera de arquitectura de la FAU-UNNE-Arquitectura IV-UPC

El objetivo del presente trabajo es exponer los resultados preliminares del Proyecto de Investigación 12C006-2013-16 “Las Representaciones Gráficas en la Formación de Alumnos de la Carrera de Arquitectura-UNNE” que estamos desarrollando para conocer la manera en que los alumnos de Arquitectura de nuestra Universidad representan el objeto arquitectónico con métodos analógicos y digitales en la actualidad. Los resultados permitirán expresar el impacto del mundo digital sobre las representaciones, permitirán conocer las habilidades y destrezas del estudiante en relación a los Sistemas de Representación a través de cortes transversales en cinco (5) momentos de la formación en la carrera de Arquitectura (nivel ingresantes, primero, segundo, cuarto y sexto años) en los ciclos lectivos 2013 a 2016. Se propone una investigación cualitativa, descriptiva-explicativa que permita identificar y conocer las distintas maneras en que los alumnos prefiguran y construyen sus imágenes arquitectónicas. Fundamentalmente nos explayamos en la experiencia del Taller Virtual Red Norte Grande, experiencia innovadora única del taller colaborativo en la Cátedra Arquitectura IV UPC.Área temática 5: Comunicación y Sistemas de Representación - Eje InvestigaciónFacultad de Arquitectura y Urbanism