ZipN is an essential FtsZ membrane tether and contributes to the septal localization of SepJ in the flamentous cyanobacterium Anabaena

The organismic unit of heterocyst-forming cyanobacteria is a filament of communicating cells connected by septal junctions, proteinaceous structures bridging the cytoplasms of contiguous cells. This distinct bacterial organization is preserved during cell division. In Anabaena, deletion of the zipN gene could not be segregated. We generated strain CSL109 that expresses zipN from a synthetic regulatable promoter. Under conditions of ZipN depletion, cells progressively enlarged, reflecting restricted cell division, and showed drastic morphological alterations including cell detachment from the filaments, to finish lysing. In contrast to the wild-type localization in midcell Z-rings, FtsZ was found in delocalized aggregates in strain CSL109. Consistently, the proportion of membrane-associated to soluble FtsZ in fractionated cell extracts was lower in CSL109. Bacterial two-hybrid analysis showed that ZipN interacts with FtsZ and other cell-division proteins including cytoplasmic Ftn6 and SepF, and polytopic FtsW, FtsX, FtsQ and FtsI. Additionally, ZipN interacted with the septal protein SepJ, and in CSL109 depletion of ZipN was concomitant with a progressive loss of septal specificity of SepJ. Thus, in Anabaena ZipN represents an essential FtsZ membrane tether and an organizer of the divisome, and it contributes to the conformation of septal structures for filament integrity and intercellular communication.Agencia Estatal de Investigación BFU2013-44686-P, BFU2016-77097-

Regulation of internal promoters in a zinc-responsive operon is influenced by transcription from upstream promoters

In the cyanobacterium Anabaena sp. strain PCC 7120 (also known as Nostoc sp. strain PCC 7120), a zinc-responsive operon (all4725-all4721) has been described, which contains 4 distinct promoters. The two most upstream ones bind Zur with high affinity, whereas the other two do not or do so with a very low affinity. In this paper, a detailed characterization of the four promoters is presented, showing that all four were induced by metal depletion, and they were constitutively derepressed in a zur mutant, despite the two downstream promoters not being direct targets for this regulator. Crucially, induction by metal depletion of the two downstream promoters was abrogated when transcription initiated at the upstream promoters was interrupted by a polar insertion midway in the operon. In contrast, insertion of a nitrogen-responsive promoter at a roughly similar position provoked the two downstream promoters to adopt a regulatory pattern mimicking that of the inserted promoter. Thus, regulation of the two downstream promoters is apparently influenced by transcription from promoters upstream. Evidence is presented indicating that the activity of the two downstream promoters is kept basal in Anabaena by repression. A regulatory model compatible with these results is proposed, where promoters controlled by repression in bacterial operons may be subjected to a hierarchical regulation depending on their position in the operon. According to this model, internal promoters may respond to stimuli governing the activity of promoters upstream by an indirect regulation and to specific stimuli by a direct regulation.Ministerio de Ciencia e Innovación y European Social Fund BFU2010-19544Junta de Andalucía y FEDER CVI2007-0316

Behavior of Poly-A onto Kaolin

A combination of geochemical variables is necessary to explain the origin of life on Earth. Thus, in this work the sorption of Poly-A on a clay mineral (kaolinite) was studied to get an insight about the sorption capacity at different times and pH values, as well as to confirm the capabilities of the clay to protect the sorbate from an external source of ionizing radiation. Poly-A presented a high percentage of sorption in the clay, especially in acidic environments, and this percentage sharply decrease in alkaline media. On the other hand, Poly-A’s recovery was higher in the system with clay, confirming its protection role

FtsZ of filamentous, heterocyst-forming cyanobacteria has a conserved N-Terminal peptide required for normal FtsZ polymerization and cell division

Filamentous cyanobacteria grow by intercalary cell division, which should involve distinct steps compared to those producing separate daughter cells. The N-terminal region of FtsZ is highly conserved in the clade of filamentous cyanobacteria capable of cell differentiation. A derivative of the model strain Anabaena sp. PCC 7120 expressing only an FtsZ lacking the amino acids 2-51 of the N-terminal peptide (1N-FtsZ) could not be segregated. Strain CSL110 expresses both 1N-FtsZ, from the endogenous ftsZ gene promoter, and the native FtsZ from a synthetic regulated promoter. Under conditions of 1N-FtsZ predominance, cells of strain CSL110 progressively enlarge, reflecting reduced cell division, and show instances of asymmetric cell division and aberrant Z-structures notably differing from the Z-ring formed by FtsZ in the wild type. In bacterial 2-hybrid assays FtsZ interacted with 1N-FtsZ. However, 1N-FtsZ-GFP appeared impaired for incorporation into Z-rings when expressed together with FtsZ. FtsZ, but not 1N-FtsZ, interacted with the essential protein SepF. Both FtsZ and 1N-FtsZ polymerize in vitro exhibiting comparable GTPase activities. However, filaments of FtsZ show a distinct curling forming toroids, whereas 1N-FtsZ form thick bundles of straight filaments. Thus, the N-terminal FtsZ sequence appears to contribute to a distinct FtsZ polymerization mode that is essential for cell division and division plane location in Anabaena.Agencia Estatal de Investigación BFU2013-44686-P BFU2016-77097-

Del basurero al museo: Arte con reciclaje

Este artículo profundiza en la incidencia entre arte y reciclaje en la vida cotidiana y el ambiente, específicamente en el campo de la mitigación y la prevención de contaminación por desechos sólidos; en este sentido, a través de la consulta y el análisis de diferentes documentos, además de la recolección de datos propios por medio de una encuesta realizada a un reducido grupo de veinte personas de diferentes demográficas —principalmente ubicadas en Bogotá D. C. y sus alrededores—, se encontró un gran contraste entre la estima que se tiene, y la práctica y el conocimiento real frente al tema del reciclaje artístico. Este artículo también hace hincapié en cómo, en teoría, esta brecha puede ser cerrada a través de diferentes proyectos y propuestas, no solo a pequeña escala en el campo individual y particular, sino a gran escala, al involucrar a instituciones educativas y al Estado. Se toman como ejemplo casos dentro y fuera del país en cuanto a la aplicación de iniciativas de este tipo

The Helicobacter pylori Genome Project : insights into H. pylori population structure from analysis of a worldwide collection of complete genomes

Helicobacter pylori, a dominant member of the gastric microbiota, shares co-evolutionary history with humans. This has led to the development of genetically distinct H. pylori subpopulations associated with the geographic origin of the host and with differential gastric disease risk. Here, we provide insights into H. pylori population structure as a part of the Helicobacter pylori Genome Project (HpGP), a multi-disciplinary initiative aimed at elucidating H. pylori pathogenesis and identifying new therapeutic targets. We collected 1011 well-characterized clinical strains from 50 countries and generated high-quality genome sequences. We analysed core genome diversity and population structure of the HpGP dataset and 255 worldwide reference genomes to outline the ancestral contribution to Eurasian, African, and American populations. We found evidence of substantial contribution of population hpNorthAsia and subpopulation hspUral in Northern European H. pylori. The genomes of H. pylori isolated from northern and southern Indigenous Americans differed in that bacteria isolated in northern Indigenous communities were more similar to North Asian H. pylori while the southern had higher relatedness to hpEastAsia. Notably, we also found a highly clonal yet geographically dispersed North American subpopulation, which is negative for the cag pathogenicity island, and present in 7% of sequenced US genomes. We expect the HpGP dataset and the corresponding strains to become a major asset for H. pylori genomics

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Utopia or Failed Opportunity? A Critical Analysis of the Peace Agreement

Este libro nació en una conversación entre los editores unas semanas antes del 2 de octubre del 2016, día en que el Acuerdo de Paz de la Habana fue sometido a plebiscito. Como muchos colombianos, nos enfrascamos en una discusión sobre diversos aspectos de lo pactado por el gobierno colombiano y las Fuerzas Armadas Revolucionarias de Colombia —FARC—. Esta inquietud de dos personas se transformó en un diálogo de veintitrés. Así, esta obra es una contribución de la Facultad de Jurisprudencia de la Universidad del Rosario al debate del fin del conflicto armado y la construcción de paz en Colombia. En él, participan profesores de esta y otras universidades colombianas con el fin de presentar una reflexión académica desde los estudios socio-jurídicos de los alcances, limitaciones y oportunidades de aprendizaje del proceso de paz y acuerdo logrado en 2016 con las FARC. En este contexto, este libro responde a la necesidad de promover una discusión informada sobre el papel del derecho y de los abogados en la estructuración e implementación de iniciativas de paz. Luego de tantos años en que los académicos han estudiado en el país la interacción conflicto armado y derecho, es esencial dar paso a una reflexión profunda que concatene esta disciplina con los escenarios de paz.This book is the outcome of a conversation between its editors several weeks before October 2, 2016, the date on which the Colombian people were to vote whether to approve the Havana Peace Agreement. Like many Colombians, we discussed different aspects and challenges of the agreement between the Colombian Government and the Revolutionary Armed Forces of Colombia –farc–. This conversation between two people soon became a dialogue among twenty-three authors. This volume is a contribution of Universidad del Rosario’s Law School to the ongoing debate around the end of the armed conflict and peacebuilding in Colombia. Professors from Universidad del Rosario and other Colombian universities shared their articles to offer insights from the socio-legal perspective to the debate on the Peace Agreement’s advantages and disadvantages, and lessons learned in this process. In this context, this work aims at promoting an informed discussion on the role of the law and lawyers in designing and implementing peace initiatives. After many years in which scholars have devoted their research to understand the interplay between the internal armed conflict and the law, it is time to begin an in-depth analysis of the interaction between the law and post-conflict scenarios