Variability of the human gut microbiota in space, time, and associated with the irritable bowel syndrome

Esta tesis doctoral se centra en el estudio de una de las comunidades microbianas más complejas y de mayor interés biomédico: la microbiota asociada al intestino distal de humanos. El objetivo principal ha sido estudiar las alteraciones potenciales de la microbiota intestinal en relación con el síndrome del intestino irritable (SII), el desorden funcional del tracto gastrointestinal más común en sociedades occidentales. Nuestra aproximación forma parte de una visión actual sobre las relaciones entre microorganismos y hospedadores que trasciende la clásica y estrecha mirada sobre patógenos concretos y enfermedades infecciosas y la desplaza hacia una concepción más de conjunto, que valora los equilibrios entre los componentes de una relación simbiótica de enorme complejidad. Se sospechaba desde hacía tiempo de alteraciones en la microbiota intestinal como uno de los factores implicados en el desencadenamiento y persistencia del SII, aunque los estudios de casos y controles no habían revelado cambios marcados en la composición de la microbiota relacionados con el SII y no se había alcanzado un consenso respecto a la implicación de bacterias específicas. Antes de abordar el papel de la microbiota intestinal en el SII, consideramos necesario estudiar en individuos sanos otras fuentes de variación en la microbiota que pueden ser relevantes a la hora de plantear diseños para evaluar su impacto en el estado de salud del hospedador. En primer lugar, las diferencias en composición entre la microbiota aislada de distintos hábitats intestinales (mucosa de distintas regiones del colon y heces). Las heces son el tipo de muestra escogido en la mayoría de estudios sobre la microbiota intestinal debido a la facilidad de su recolección. Sin embargo, la microbiota fecal podría no ser enteramente representativa de las comunidades asociadas a la mucosa del colon. También analizamos la variación temporal “normal” (en ausencia de perturbaciones) en la composición de la microbiota fecal. Dado que los distintos tipos de muestra pueden revelar información distinta y complementaria sobre la microbiota intestinal, nuestro primer estudio sobre el SII consistió en comparar la composición microbiana de pacientes con SII y controles sanos, en heces y varios puntos de la mucosa del colon. Los resultados de los estudios de casos y controles realizados en el SII nos llevaron a plantear un estudio longitudinal en el que comparamos la microbiota fecal de pacientes concretos en momentos con distintos síntomas intestinales. Monitorizar a pacientes individuales permite superar la confusión introducida por la gran variación entre individuos que es problemática en los estudios transversales. La aproximación metodológica ha consistido en analizar directamente el material genético aislado de las muestras intestinales, lo que posibilita el estudio de comunidades microbianas complejas en las que la mayoría de sus miembros no puede ser cultivada. La diversidad microbiana en las muestras ha sido estimada a partir de la amplificación y secuenciación de los genes del rRNA 16S, el marcador filogenético más ampliamente utilizado en ecología microbiana. Además, analizamos por primera vez las alteraciones potenciales en la composición genómica (metagenoma) y la expresión génica (metatranscriptoma) de la microbiota fecal de individuos con SII en relación con la presentación de síntomas. Nuestros estudios aportan evidencias que permiten orientar las futuras investigaciones de modo más eficiente. Las principales conclusiones respecto a la microbiota intestinal en afectados por el SII son que ésta presenta una menor diversidad y una mayor inestabilidad temporal que la de individuos sanos, más allá de las alteraciones estructurales concretas detectadas en distintos compartimentos intestinales y los cambios detectados en momentos con sintomatología aguda.This PhD project focuses on the study of one of the most complex microbial communities and of high biomedical interest: the microbiota associated with the distal gut of humans. The main objective was to study the potential alterations of the intestinal microbiota in relation to the irritable bowel syndrome (IBS), the most common functional disorder of the gastrointestinal tract in Western countries. Our approach is part of a global view on the relationship between host and microbes that goes beyond the narrow classical view on specific pathogens and infectious diseases, and moves towards a more overall view, which evaluates the balance between the components of a symbiotic relationship of enormous complexity. Alterations in the intestinal microbiota have been longly suspected as one of the factors involved in the onset and persistence of IBS, although case-control studies had not revealed marked changes in the composition of the microbiota and had not reached a consensus regarding the involvement of specific bacteria. Before addressing the role of the intestinal microbiota in IBS, we consider it necessary to study in healthy individuals other sources of variation in the microbiota that may be relevant when designing studies to evaluate their impact on the host’s health status. First, the structural differences between the microbiota isolated from several intestinal habitats (different regions of the colonic mucosa and faeces). Faeces are the type of sample chosen in most studies on the intestinal microbiota because they are easily collected. However, the faecal microbiota might not be entirely representative of the communities associated with the colonic mucosa. We also analysed the ‘normal’ temporal variation (in the absence of perturbation) in the composition of the faecal microbiota. Since the different sample types can reveal different and complementary information on the intestinal microbiota, our first study on IBS was to compare the microbial composition of IBS patients and healthy controls in faeces and several regions of the colonic mucosa. The results of case-control studies on IBS led us to undertake a longitudinal study. It allowed us to compare the faecal microbiota within single patients at moments with different bowel symptoms, thus overcoming the confusion introduced by the large between-subject variability that is problematic in cross-sectional studies. The methodological approach consisted of the direct analysis of the genetic material isolated from the intestinal samples. This allows the study of complex microbial communities where the majority of the members can not be cultured. Microbial diversity in the samples was estimated through the amplification and sequencing of the 16S rRNA genes, the phylogenetic marker most widely used in microbial ecology. In addition, we analysed for the first time the potential alterations in the genome composition (metagenome) and the gene expression (metatranscriptome) of the faecal microbiota in IBS patients related to symptom presentation. Our studies provide evidences to guide future investigations more efficiently. Beyond the specific structural alterations detected in different intestinal compartments and the changes detected in association with acute symptoms, the main conclusions regarding the intestinal microbiota in IBS patients is that it is less diverse and more unstable over time than that of healthy subjects

Penalized functional spatial regression

This paper is focus on spatial functional variables whose observa- tions are realizations of a spatio-temporal functional process. In this context, a new smoothing method for functional data presenting spa- tial dependence is proposed. This approach is based on a P-spline estimation of a functional spatial regression model. As alternative to other geostatistical smoothing methods (kriging and kernel smooth- ing, among others), the proposed P-spline approach can be used to estimate the functional form of a set of sample paths observed only at a finite set of time points, and also to predict the corresponding func- tional variable at a new location within the plane of study. In order to test the good performance of the proposed method, two simulation studies and an application with real data will be developed and the results will be compared with functional kriging.Financial support from the project P11-FQM-8068 from Consejería de Innovación, Ciencia y Empresa. Junta de Andalucía, Spain and the projects MTM2013-47929-P and MTM 2011-28285-C02-C2 from Secretaría de Estado Investigación, Desarrollo e Innovación, Ministerio de Economía y Competitividad, Spain

Prediction of functional data with spatial dependence: a penalized approach

This paper is focus on spatial functional variables whose observations are a set of spatially correlated sample curves obtained as realizations of a spatio-temporal stochastic process. In this context, as alternative to other geostatistical techniques (kriging, kernel smoothing, among others), a new method to predict the curves of temporal evolution of the process at unsampled locations and also the surfaces of geographical evolution of the variable at unobserved time points is proposed. In order to test the good performance of the proposed method, two simulation studies and an application with real climatological data have been carried out. Finally, the results were compared with ordinary functional kriging.Project P11-FQM-8068 from Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía, SpainProjects MTM2013-47929-P, MTM2011-28285-C02-C2 and MTM 2014-52184-P from Secretaría de Estado Investigación, Desarrollo e Innovación, Ministerio de Economía y Competitividad, Spai

Metatranscriptomic Approach to Analyze the Functional Human Gut Microbiota

The human gut is the natural habitat for a large and dynamic bacterial community that has a great relevance for health. Metagenomics is increasing our knowledge of gene content as well as of functional and genetic variability in this microbiome. However, little is known about the active bacteria and their function(s) in the gastrointestinal tract. We performed a metatranscriptomic study on ten healthy volunteers to elucidate the active members of the gut microbiome and their functionality under conditions of health. First, the microbial cDNAs obtained from each sample were sequenced using 454 technology. The analysis of 16S transcripts showed the phylogenetic structure of the active microbial community. Lachnospiraceae, Ruminococcaceae, Bacteroidaceae, Prevotellaceae, and Rickenellaceae were the predominant families detected in the active microbiota. The characterization of mRNAs revealed a uniform functional pattern in healthy individuals. The main functional roles of the gut microbiota were carbohydrate metabolism, energy production and synthesis of cellular components. In contrast, housekeeping activities such as amino acid and lipid metabolism were underrepresented in the metatranscriptome. Our results provide new insights into the functionality of the complex gut microbiota in healthy individuals. In this RNA-based survey, we also detected small RNAs, which are important regulatory elements in prokaryotic physiology and pathogenicity

Documentation and virtual reconstruction applied to the restauration of large format pictoric works: the mural canvas painting from the Zambrano pharmacy

[ES] El objetivo de este trabajo es exponer la utilidad de la fotogrametría y la reconstrucción virtual aplicada a la restauración de obras de gran formato, poniendo como ejemplo la intervención llevada a cabo en la farmacia Zambrano de Granada; en concreto, se trabajó con un lienzo mural realizado a finales del s. XIX y situado en el techo de la misma simulando una pintura al fresco. El lienzo había sido adherido con un adhesivo a base de cola, presumiblemente de origen animal, quedando la impronta de una pintura mural anterior en el reverso de la tela. Al iniciar la intervención restauradora de la pintura, y una vez desmontada, se detectó el problema de la documentación inicial; debido a las grandes dimensiones de la obra no era posible obtener una imagen ortogonal completa de calidad mediante fotografía tradicional. En ese momento se decidió emplear la fotogrametría como herramienta para la correcta documentación de las diferentes fases de la restauración (documentación inicial, limpieza mecánica del reverso, retirada de la protección del anverso, limpieza del anverso y reintegración pictórica). Concluida la restauración, el sistema de montaje expositivo planteado simulando el techo de la farmacia original dejaba oculto el reverso del lienzo, por lo que era necesario documentar la impronta de la pintura mural anterior. Así, se efectuó una reconstrucción virtual para evitar su pérdida. El procesado fotogramétrico permitió obtener ortofotografías de gran calidad y detalle, lo que ha puesto de manifiesto la idoneidad de esta técnica. Por otra parte, la reconstrucción realizada demostró ser una herramienta de utilidad, no solo para la documentación y registro de la pintura, sino para su correcta lectura y apreciación.[EN] The aim of this paper is to explain the convenience of photogrammetry and virtual reconstruction applied to the restoration of large format canvas. This study presents the application of these techniques to the restoration and musealization of a late 19th century mural canvas painting attached to the ceiling of the Zambrano Pharmacy (Granada, Spain). The painting is an example of the allegorical motifs that could be found in 19th and 20th century pharmacies. It represents a group of cherubs and allegorical figures of Science or Pharmacy sitting in the clouds; the scene is surrounded by an architectural frame. The mural painting by Francisco Morón & Luján (Granada, 1846 - Huércal-Overa, Almería, 1899) shows his signature in the lower right corner of the painting. The painting was in a good overall condition, but presented considerable yellowing and darkening (due to exposure to nearby pollution from the street, dust, etc.) that required its cleaning to reveal its true colors. In 2018, the pharmacy was acquired by the University of Granada, initiating its transfer to the conservation laboratories for its restoration, with two aims: recovering its original appearance, and preparing for its display in the “Ciencia, ciudad y cambio” exhibition (Hospital Real of Granada, February 6th to may 17th 2019); to this day, the painting is located in the crossing of the Hospital Real. Once the intervention started, its large dimensions (7.6 x 3.3 m) made it impossible to obtain a complete high-quality orthogonal image using traditional photography methods. Therefore, it was decided to use photogrammetry for the correct documentation of: a) the initial state of the painting, b) the different restoration phases (initial documentation, mechanical cleaning of the reverse, removal of the protection of the front, cleaning of the front and pictorial reintegration), and c) the final result after the restoration process. Furthermore, this canvas was attached to the ceiling presumably with an animal glue adhesive, and during its intervention it was observed that the imprint of an earlier mural painting was attached to its reverse. Since the reverse of the canvas was hidden by the final mounting system, it was necessary to document the imprint of the previous mural painting adhered to the reverse of the canvas. To recreate the original painting and to allow a correct study and comprehension of this work, a virtual reconstruction based on the photogrammetric documentation of the reverse of the painting was achieved. The photogrammetric processing allowed us to obtain high-quality orthogonal images (10000 x 5000 px), thus demonstrating the suitability of this technique for the documentation of a large format canvas. The images obtained were also useful to study the dimensions of the paint, with a total area of 25 m2 . Agisoft PhotoScan Professional was used for the photogrammetric model; the three-dimensional (3D) models and the textures were transferred to a 3D free software (Blender) for the rendering and recreation of the models. On the other hand, the virtual reconstruction was made using Adobe Photoshop to recover the entire painting. The methodology consisted in working with different layers to paint the missing parts of the motifs and the simulated architecture; then, the missing parts were reconstructed based on the preserved paint (24.5% of the total area) and, finally, textures and filters were incorporated to simulate the appearance of a mural painting. This research has proved photogrammetry is suitable for the documentation of a restoration process for large format pictoric works, since this technique allows to obtain high resolution orthophotos from the different intervention phases. Additionally, the virtual reconstruction has proven to be a useful tool for the documentation of the painting, its registration and its visualization; it can also recreate the decorative pattern and original colors.Esta intervención ha sido financiada por el Secretariado de Conservación y Restauración de la Universidad de Granada.Calero-Castillo, AI.; Carrasco-Huertas, A.; Durbán-García, M.; Durán-Suárez, JA. (2020). Documentación y reconstrucción virtual en restauración de obras pictóricas de gran formato: el lienzo mural de la farmacia Zambrano. Virtual Archaeology Review. 11(23):141-152. https://doi.org/10.4995/var.2020.13343OJS1411521123Abate, D., Menna, F., Remondino, F., & Gattari, M. (2014). 3D painting documentation: evaluation of conservation conditions with 3D imaging and ranging techniques. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XL-5, 1-8. https://doi.org/10.5194/isprsarchives-XL-5-1-2014Angheluta, L. M., & Radvan, R. (2019). Macro photogrammetry for the damage assessment of artwork painted surfaces. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLII-2/W15, 101-107. https://doi.org/10.5194/isprs-archives-XLII-2-W15-101-2019Aparicio Resco, A., & Figueiredo, C. (2017). El grado de evidencia histórico-arqueológica de las reconstrucciones virtuales: hacia una escala de representación gráfica. Revista Otarq: Otras arqueologías, 1, 235-247. https://doi.org/10.23914/otarq.v0i1.96Barros García, J. M., Fuentes Porto, A., & Pérez Marín, E. (2010). Tratamientos estéticos aplicados en las pinturas murales sobre lienzo de la Galería Dorada. Parte I: limpieza del color y estudio de faltantes colorimétricos. In Congreso Internacional de Restauración de pinturas sobre lienzo de gran formato (pp. 269-184). Valencia: Universitat Politècnica de València.Cremonesi, P. (2014). El ambiente acuoso para el tratamiento de obras polícromas. Villatora: Il prato publishing house srl.D'Amelio, S., & Lo Brutto, M. (2009). Close range photogrammetry for measurement of paintings surface deformations. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 38, 1-6.Fazio, L., & Lo Brutto, M. (2020). 3D survey for the archaeological study and virtual reconstruction of the sanctuary of Isis in the ancient Lilybaeum (Italy). Virtual Archaeology Review, 11(22), 1-14. https://doi.org/10.4995/var.2020.11928Ferrari, I. & Quarta, A. (2018). The Roman pier of San Cataldo: from archaeological data to 3D reconstruction. Virtual Archaeology Review, 10(20), 28-39. https://doi.org/10.4995/var.2019.7957García Gago, J. M. (2014). Documentación y análisis geométrico del patrimonio arquitectónico a partir de métodos fotogramétricos con una y múltiples imágenes. (Doctoral Dissertation, University of Salamanca, Spain). Retrieved from: http://hdl.handle.net/10366/127361Generalitat de Catalunya (2013). Mapping Sant Climent de Taüll. Retrieved March 27, 2020, from http://pantocrator.cat/esGisbert Santaballa, A. (2019). La arqueología virtual como herramienta didáctica y motivadora. Revista Tecnología, Ciencia y Educación, (13), 119-147.González López, M. J., & Martínez Calvo, V. (2009). Reintegración virtual de lagunas. Las pinturas de la Sala de los Reyes de la Alhambra de Granada. Revista pH, 70, 98-113. https://doi.org/10.33349/2009.70.2754Karras, G., Petsa, E. Dimarogona, A., & Kouroupis, S. (2001). Photo-Textured Rendering of Developable Surfaces in Architectural Photogrammetry. In Proc of International Symposium of Virtual and Augmented Architecture (VAA01) (pp. 147-158). Dublin: Ireland. https://doi.org/10.1007/978-1-4471-0337-0_17Korumaz, M., & Gulec Korumaz, A. (2010). Reproduction of Turkish traditional wall-painting using close range photogrammetry, a case study in Gaziantep. International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, XXXVIII-Part 5, 367-371.London Charter (2009). London charter for the computer-based visualisation of cultural heritage. Retrieved from: http://www.londoncharter.orgLópez Menchero, V. M. (2011). Propuesta para profundizar en La Carta de Londres y mejorar su aplicabilidad en el campo del patrimonio arqueológico. Virtual Archaeology Review, 2(4), 65-69. https://doi.org/10.4995/var.2011.4557Maldonado Ruiz, A. (2020). La aplicación de la fotogrametría (SFM) y las nuevas tecnologías para la mejora de la documentación, difusión y divulgación del patrimonio arqueológico (Doctoral dissertation, University of Granada). Retrieved from https://dialnet.unirioja.es/servlet/tesis?codigo=261576Martínez Justicia, M. J. (1996). Antología de textos sobre restauración. Jaén: Universidad.Martínez Gil, T., & Santacana Mestre, J. (2013). De lo real a lo digital: la arqueología reconstructiva y la obtención de imágenes virtuales para la investigación en la didáctica del patrimonio. Her&Mus. Heritage & Museography, (13), 16-35.Mora, P., Mora, L., & Philippot, P. (2003). La conservación de pinturas murales. Colombia: Universidad Externado de Colombia, Facultad de Estudios del Patrimonio Cultural.Principios de Sevilla (2011). Principios internacionales de Arqueología Virtual. Forum Internacional de Arqueología Virtual. Retrieved from: http://smartheritage.com/wp-content/uploads/2016/06/PRINCIPIOS-DE-SEVILLA.pdfRegidor Ros, J. L., Palumbo, M., Gómez Chaparro, G. & Clavel Piá, I. (2006). Restauración y solución propuesta para la exposición de los fragmentos conservados en la bóveda de la iglesia de los Santos Juanes de Valencia. Arché, (1), 45-52. http://hdl.handle.net/10251/32363Regidor Ros, J.L., Valcárcel Andrés, J. & Blanco-Moreno Pérez, F. (2010). Readaptación dimensional de la obra pictórica La glorificación de San Francisco de Borja a su espacio arquitectónico mediante el sistema REGIID. In Congreso Internacional de Restauración de pinturas sobre lienzo de gran formato (pp.425-437). Valencia: Universitat Politècnica de València.Santamaría Peña, J. & Sanz Martínez, T. (2011). Fundamentos de fotogrametría. La Rioja: Servicio de publicaciones. Universidad de La Rioja.Santos Moreno, M. D. (1997), Pintura del siglo XIX en Granada: arte y sociedad. (Doctoral dissertation, University of Granada). Retrieved from https://digibug.ugr.es/handle/10481/28926Villarquide Jevenois, A. (2005). La Pintura sobre tela II. Alteraciones, materiales y tratamientos de restauración. Guipúzcoa: Nerea

Estudio colorimétrico de barnices tradicionales aplicados sobre papel sometidos a ensayos de envejecimiento acelerado

El empleo de barnices como acabado final en obra gráfica cumple una función estética y protectora. Con el tiempo, o debido a factores adversos, estos barnices pueden sufrir una serie de alteraciones en su color, distorsionando el aspecto original de la obra subyacente. Conocer las variaciones cromáticas de estos materiales resulta esencial de cara a su selección como barniz de conservación. Este trabajo recoge los resultados obtenidos del estudio colorimétrico llevado a cabo sobre una serie de probetas de papel barnizadas sometidas a distintos ensayos físico-químicos (humedad ambiental, inmersión en agua, calor seco y envejecimiento acelerado en cámara climática) que buscan recrear condiciones adversas a las que pueden verse sometidos este tipo de documentos como consecuencia de su envejecimiento natural, la acción de determinados factores de degradación o la acción restauradora. El papel seleccionado como soporte ha sido Somerset 100% algodón al que se le han aplicado distintos barnices de uso tradicional en obra gráfica: goma laca, goma arábiga, clara de huevo, colofonia y dammar). El color de estas probetas se ha estudiado siguiendo el sistema CIEL*a*b* 1976, calculando las diferencias colorimétricas antes y después de los ensayos físico-químicos y de envejecimiento.The use of varnishes as a final coat in graphic work fulfills an aesthetic and protective function. Over time, or due to adverse conditions, these varnishes undergo a series of degradations in their color that can distort the original appearance of the underlying work. Knowing the chromatic variations of these materials is essential for their selection as a conservation varnish. This work collects the results obtained from the colorimetric study carried out on a series of samples of paper with varnish exposing to different physical-chemical tests (humidity, immersion in water, dry heat and accelerated aging) tests that recreate adverse conditions to which this type of woks may be exposed as a consequence of its natural aging, the action of certain degradation factors or the restorative action. For this purpose, Somerset 100% cotton paper has been selected, which has been applied different varnishes of traditional use in graphic works: shellac, gum arabic, egg white, rosin and dammar. The color of these samples has been studied following the CIEL*a*b* 1976 system, calculating the colorimetric differences from the comparison between the reference samples and the samples after the physical-chemical tests

Actualización en odontopediatría 2007

En el presente trabajo se analizan las publicaciones relacionadas con la odontopediatría aparecidas durante el año 2007. Debido a la gran cantidad de artículos publicados, estos se han distribuido en cinco apartados: 1) control de conducta; 2) pulpa; 3) operatoria dental; 4) traumatismos; y 5) miscelánea

Differential Effects of Antibiotic Therapy on the Structure and Function of Human Gut Microbiota

The human intestinal microbiota performs many essential functions for the host. Antimicrobial agents, such as antibiotics (AB), are also known to disturb microbial community equilibrium, thereby having an impact on human physiology. While an increasing number of studies investigate the effects of AB usage on changes in human gut microbiota biodiversity, its functional effects are still poorly understood. We performed a follow-up study to explore the effect of ABs with different modes of action on human gut microbiota composition and function. Four individuals were treated with different antibiotics and samples were taken before, during and after the AB course for all of them. Changes in the total and in the active (growing) microbiota as well as the functional changes were addressed by 16S rRNA gene and metagenomic 454-based pyrosequencing approaches. We have found that the class of antibiotic, particularly its antimicrobial effect and mode of action, played an important role in modulating the gut microbiota composition and function. Furthermore, analysis of the resistome suggested that oscillatory dynamics are not only due to antibiotic-target resistance, but also to fluctuations in the surviving bacterial community. Our results indicated that the effect of AB on the human gut microbiota relates to the interaction of several factors, principally the properties of the antimicrobial agent, and the structure, functions and resistance genes of the microbial community

Somos lo que comimos: ¿Comer carne nos convirtió en seres inteligentes?

Què és el que ens fa diferents d'altres animals? Els antropòlegs porten molt temps tractant de saber que va ser el que ens va fer humans i com es va diferenciar el nostre llinatge de la resta de primats. Diferents recerques apunten que els canvis produïts en l'alimentació dels nostres avantpassats van ser una important força selectiva en l'evolució i en particular l'evolució del nostre cervell. No hi ha dubte que “som el que mengem” però que també som el que vam menjar fa milions d'anys. Us convido a endinsar-vos a l'increïble món de l'evolució humana per analitzar d' on venim i que vam fer en el passat per poder entendre millor el present.¿Qué es lo que nos hace diferentes de otros animales? Los antropólogos llevan mucho tiempo tratando de saber que fue lo que nos hizo humanos y cómo se diferenció nuestro linaje del resto de primates. Diferentes investigaciones apuntan que los cambios producidos en la alimentación de nuestros antepasados fueron una importante fuerza selectiva en la evolución y en particular la evolución de nuestro cerebro. No cabe duda que “somos lo que comemos” pero que también somos lo que comimos hace millones de años. Os invito a adentraros en el increíble mundo de la evolución humana para analizar de dónde venimos y que hicimos en el pasado para poder entender mejor el presente

Bacteria associated with Copestylum (Diptera, Syrphidae) larvae and their cactus host Isolatocereus dumortieri

We describe the gut bacterial diversity inhabiting two saprophagous syrphids and their breeding substrate (decayed tissues of the columnar cactus Isolatocereus dumortieri). We analyzed the gut microbiota of Copestylum latum (scooping larvae that feed on decayed cactus tissues) and Copestylum limbipenne (whose larvae can also feed on semiliquid tissues) using molecular techniques. DNA was extracted from larval guts and cactus tissues. The V1-V3 region of the 16S rRNA genes was amplified and sequenced. A total of 31079 sequences were obtained. The main findings are: C. limbipenne is dominated by several Enterobacteriaceae, including putative nitrogen-fixing genera and pectinolitic species and some denitrifying species, whereas in C. latum unclassified Gammaproteobacteria predominate. Decayed tissues have a dominant lactic acid bacterial community. The bacterial communities were more similar between larval species than between each larva and its breeding substrate. The results suggest that the gut bacterial community in these insects is not strongly affected by diet and must be dependent on other factors, such as vertical transmission, evolutionary history and host innate immunity.This research was funded by AECID (project A/020305/08), FOMIX CONACYT-Hidalgo (project 95828) and SEP-CONACYT (project 84127) to M. A. M.-G., and BFU2009-12895-C02-01 from the Ministerio de Ciencia e Inovación to A.L. A.P.M. acknowledge the scholarship provided by The Alβan programme, the European Union Programme of High Level Scholarships for Latin America, No. E07D401138MX and CONACYT program (207522) for doctoral fellowship. A.D. is recipient of a fellowship from the Instituto de Salud Carlos III, Spain