Bioinformatic analysis of gene regulation in Geobacter sulfurreducens

Background Geobacteraceae are a family of microorganisms from the delta subdivision of Proteobacteria. They have potential for environmental bioremediation and electricity generation. In this presentation, we describe our recent bioinformatic analyses of gene regulation in Geobacter sulfurreducens, a model representative of this family. Results and conclusion We have developed an online database, GSEL (Geobacter Sequence Elements), which compiles regulatory information for G. sulfurreducens. We have recently completed the development of a new, significantly expanded and updated, relational version 2 of the GSEL database and its accompanying online query system, which compiles manually curated information on operon organization and transcription regulatory elements in the genome of G. sulfurreducens. GSEL v. 2 incorporates a graphical browser and provides significantly expanded search capabilities. It also includes new information on predicted and/or experimentally validated genome regulatory sites and provides links to information from microarray experiments stored in public gene expression databases, and to original publications describing how particular regulatory interactions were identified. Using sequence and gene expression analyses, we investigated target genes and promoters regulated by RpoN, an alternative RNA polymerase sigma factor, which regulates a variety of important cellular processes in G. sulfurreducens. Our current studies are focusing on an investigation of several transcription regulatory systems involved in RpoN-dependent regulatory pathways. We have investigated target regulatory sites for an enhancer binding protein, PilR, which participates in RpoN-dependent transcriptional regulation of the pilA gene encoding structural pilin. We predicted multiple PilR-regulated sites upstream of operons related to biosynthesis, assembly, and function of pili and flagella, type II secretory pathways, and cell wall biogenesis. We also investigated sequence changes and molecular classification of the TetR family of transcriptional regulators. In G. sulfurreducens, we identified RpoN-regulated promoters upstream of several operons containing tetR family genes. The genome of G. sulfurreducens contains nine tetR family genes. Some of them are located upstream of operons encoding functionally important c-type cytochromes. In order to better understand the roles of TetR family members in the ability of Geobacteraceae to participate in electron transfer, we investigated phylogenetic relationships among TetR proteins in Geobacteraceae and in other microbial species. We identified their conserved and variable domains, which may be important for the diversity of their functional roles, and classified them into subgroups based on sequence similarities

Bacterial Diversity and the Geochemical Landscape in the Southwestern Gulf of Mexico

Marine sediments are an example of one of the most complex microbial habitats. These bacterial communities play an important role in several biogeochemical cycles in the marine ecosystem. In particular, the Gulf of Mexico has a ubiquitous concentration of hydrocarbons in its sediments, representing a very interesting niche to explore. Additionally, the Mexican government has opened its oil industry, offering several exploration and production blocks in shallow and deep water in the southwestern Gulf of Mexico (swGoM), from which there are no public results of conducted studies. Given the higher risk of large-scale oil spills, the design of contingency plans and mitigation activities before oil exploitation is of growing concern. Therefore, a bacterial taxonomic baseline profile is crucial to understanding the impact of any eventual oil spill. Here, we show a genus level taxonomic profile to elucidate the bacterial baseline, pointing out richness and relative abundance, as well as relationships with 79 abiotic parameters, in an area encompassing ∼150,000 km2, including a region where the exploitation of new oil wells has already been authorized. Our results describe for the first time the bacterial landscape of the swGoM, establishing a bacterial baseline “core” of 450 genera for marine sediments in this region. We can also differentiate bacterial populations from shallow and deep zones of the swGoM based on their community structure. Shallow sediments have been chronically exposed to aromatic hydrocarbons, unlike deep zones. Our results reveal that the bacterial community structure is particularly enriched with hydrocarbon-degrading bacteria in the shallow zone, where a greater aromatic hydrocarbon concentration was determined. Differences in the bacterial communities in the swGoM were also observed through a comprehensive comparative analysis relative to various marine sediment sequencing projects, including sampled sites from the Deep Water Horizon oil spill. This study in the swGoM provides clues to the bacterial population adaptation to the ubiquitous presence of hydrocarbons and reveals organisms such as Thioprofundum bacteria with potential applications in ecological surveillance. This resource will allow us to differentiate between natural conditions and alterations generated by oil extraction activities, which, in turn, enables us to assess the environmental impact of such activities

Los lenguajes en la cultura del WhatsApp

his research work aims to reflect on the symbolic forms (gif, sticker, emoji) used by users of the WhatsApp application. (gif, sticker, emoji) used by users of the WhatsApp application. These forms are These forms are so named because through them new codes are created within the language, understanding language as a way of configuring identity and culture, giving new meanings to everyday new meanings to everyday relationships, at the same time that these symbolic forms (gifs, stickers and emoji (gif, sticker and emoji) configure and reconfigure the communicational environment. In the first instance, we locate the context where this new culture or cyberculture in which we develop and in which we in which we develop and in which we find significant changes in the communication process, such as interactivity. interactivity, this new space in which these symbolic forms are originated and used (gifs, video, audio, video, etc.). these symbolic forms (gif, sticker, emoji) are originated and used. We will then reflect on them through the philosophy of language to expose how it is how our language changes when it comes to communicating, and we also intend to show that through this language with which we communicate. through this language with which we express ourselves is making a gap in the communication, at the same time we will show communication, at the same time we will present if this new visual language (gif, sticker, emoji) used mainly in WhatsApp, emoji) used mainly in WhatsApp is established as a new language, in addition to expose if through this to expose if through this language the truthfulness and intention of the message is achieved.El presente trabajo de investigación se propone reflexionar acerca de las formas simbólicas (gif, sticker, emoji) utilizadas por los usuarios de la aplicación WhatsApp. Estas formas son nombradas así porque a través de ellas se crean nuevos códigos dentro del lenguaje, entendiendo al lenguaje como modo de configuración de la identidad y la cultura, dando nuevos sentidos a las relaciones cotidianas, al mismo tiempo que estas formas simbólicas (gif, sticker y emoji) configuran y reconfiguran el entorno comunicacional. En primera instancia, ubicamos el contexto donde surge esta nueva cultura o cibercultura en la que nos desarrollamos y en la que encontramos cambios significativos en el proceso de comunicación, como la interactividad, este nuevo espacio en el que se originan y se usan estas formas simbólicas (gif, sticker, emoji). Luego reflexionaremos sobre ellas a través de la filosofía de lenguaje para exponer cómo es que cambia nuestro lenguaje a la hora de comunicarnos asimismo pretendemos mostrar que a través de este lenguaje con el que nos expresamos está haciendo una brecha en la comunicación, al mismo tiempo presentaremos si este nuevo lenguaje visual (gif, sticker, emoji) utilizado principalmente en el WhatsApp se instaura como un nuevo lenguaje, además de exponer si a través de este lenguaje se logra la veracidad e intención del mensaje

Effet du nouvel activateur transcriptionnel CmrA sur la résistance et la virulence des souches de Pseudomonas aeruginosa

International audienc

Multirésistance de Pseudomonas aeruginosa : une nouvelle voie d’induction CmrA-dépendante du système d’efflux MexEF-OprN

International audienc

Carbonyl stress induces the efflux system MexEF-OprN in Pseudomonas aeruginosa via a novel transcriptional regulator, CmrA

International audienc

Toxic Electrophiles Induce Expression of the Multidrug Efflux Pump MexEF-OprN in Pseudomonas aeruginosa through a Novel Transcriptional Regulator, CmrA

International audienceThe multidrug efflux system MexEF-OprN is produced at low levels in wild-type strains of Pseudomonas aeruginosa However, in so-called nfxC mutants, mutational alteration of the gene mexS results in constitutive overexpression of the pump, along with increased resistance of the bacterium to chloramphenicol, fluoroquinolones, and trimethoprim. In this study, analysis of in vitro-selected chloramphenicol-resistant clones of strain PA14 led to the identification of a new class of MexEF-OprN-overproducing mutants (called nfxC2) exhibiting alterations in an as-yet-uncharacterized gene, PA14_38040 (homolog of PA2047 in strain PAO1). This gene is predicted to encode an AraC-like transcriptional regulator and was called cmrA (for chloramphenicol resistance activator). In nfxC2 mutants, the mutated CmrA increases its proper gene expression and upregulates the operon mexEF-oprN through MexS and MexT, resulting in a multidrug resistance phenotype without significant loss in bacterial virulence. Transcriptomic experiments demonstrated that CmrA positively regulates a small set of 11 genes, including PA14_38020 (homolog of PA2048), which is required for the MexS/T-dependent activation of mexEF-oprN PA2048 codes for a protein sharing conserved domains with the quinol monooxygenase YgiN from Escherichia coli Interestingly, exposure of strain PA14 to toxic electrophilic molecules (glyoxal, methylglyoxal, and cinnamaldehyde) strongly activates the CmrA pathway and upregulates MexEF-OprN and, thus, increases the resistance of P. aeruginosa to the pump substrates. A picture emerges in which MexEF-OprN is central in the response of the pathogen to stresses affecting intracellular redox homeostasis

In vitro antibacterial activity of the ethanol extract of the leaves of morinda citrifolia L. (noni) against escherichia coli ATCC 25922.

Objetivo: Demostrar la actividad antibacteriana in vitro del extracto etanólico de las hojas de Morinda citrifolia L. (noni) frente a Escherichia coli ATCC 25922. Método: Tiene un enfoque cuantitativo, experimental, de corte transversal y prospectivo. Se obtuvo extractos etanólicos de las hojas de Morinda citrifolia L.(noni) mediante maceración con etanol, además se evaluó la actividad antibacteriana frente a Escherichia coli, mediante la técnica de difusión en pozo, los resultados fueron analizados estadísticamente con un nivel de significancia del 0.05 empleando las pruebas de ANOVA y Tukey. Resultados: Se presencio metabolitos secundarios como alcaloides, compuestos fenólicos y triterpenos/esteroides; por otro lado, los valores de los halos de inhibición del extracto etanólico al 100% fue de 23,73 + 0,54mm, para el 75% de 21,08 + 0,41mm y para el 50% fue de 17,30 + 0,36mm; así mismo, el control negativo (etanol) obtuvo halo de inhibición de 6,27 + 0,34mm y el control positivo obtuvo halo 29,34 + 0,36mm. Conclusión: Se logró demostrar que el extracto etanólico de las hojas de Morinda citrifolia L.(noni) a las concentraciones del 50%, 75% y 100%, poseen actividad antibacteriana in vitro frente a Escherichia coli ATCC 25922