Diversity of archaea and niche preferences among putative ammonia-oxidizing Nitrososphaeria dominating across European arable soils

Archaeal communities in arable soils are dominated by Nitrososphaeria, a class within Thaumarchaeota comprising all known ammonia-oxidizing archaea (AOA). AOA are key players in the nitrogen cycle and defining their niche specialization can help predicting effects of environmental change on these communities. However, hierarchical effects of environmental filters on AOA and the delineation of niche preferences of nitrososphaerial lineages remain poorly understood. We used phylogenetic information at fine scale and machine learning approaches to identify climatic, edaphic and geomorphological drivers of Nitrososphaeria and other archaea along a 3000 km European gradient. Only limited insights into the ecology of the low-abundant archaeal classes could be inferred, but our analyses underlined the multifactorial nature of niche differentiation within Nitrososphaeria. Mean annual temperature, C:N ratio and pH were the best predictors of their diversity, evenness and distribution. Thresholds in the predictions could be defined for C:N ratio and cation exchange capacity. Furthermore, multiple, independent and recent specializations to soil pH were detected in the Nitrososphaeria phylogeny. The coexistence of widespread ecophysiological differences between closely related soil Nitrososphaeria highlights that their ecology is best studied at fine phylogenetic scale.The Digging Deeper project was funded through the 2015–2016 BiodivERsA call, with national funding from the Swiss National Science Foundation (grant 31BD30-172466), the Deutsche Forschungsgemeinschaft (grant 317895346), the Swedish Research Council Formas (grant 2016-0194), the Spanish Ministerio de Economía y Competitividad (grant PCIN-2016-028) and the Agence Nationale de la Recherche (grant ANR-16-EBI3-0004-01). The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. Sequencing was performed by the SNP&SEQ Technology Platform in Uppsala. The facility is part of the National Genomics Infrastructure (NGI) Sweden and Science for Life Laboratory. The SNP&SEQ Platform is also supported by the Swedish Research Council and the Knut and Alice Wallenberg Foundation

La evolución del derecho a la educación en Colombia entre 1820 a 1876, como un derecho económico, social y cultural

In examining the evolution of the right to education in New Granada, Gran Colombia and the United States of Colombia, a major effort is evidenced by Francisco de Paula Santander, Mariano Ospina Rodriguez to promote the development of education as a right which should be free and compulsory.However, the project initiated by Santander Ospina Rodriguez and other presidents of the period covered from 1820 to 1876, is to prevent the social, political, cultural and civil wars that were designed to search for autonomy, freedom and independence.Al examinar la evolución del derecho a la educación en la Nueva Granada, la Gran Colombia y los Estados Unidos de Colombia, se evidencia un importante esfuerzo por parte de Francisco de Paula Santander y Mariano Ospina Rodríguez de promover el desarrollo de la educación como un derecho que debía ser gratuito y obligatorio.Sin embargo, el proyecto iniciado por Santander y Ospina Rodríguez y demás presidentes de la época comprendida entre 1820 a 1876, tiene como obstáculo los problemas sociales, políticos, culturales y las guerras civiles que tenían como fin la búsqueda de la autonomía, libertad e independencia

Diversity of archaea and niche preferences among putative ammonia-oxidizing Nitrososphaeria dominating across European arable soils

Archaeal communities in arable soils are dominated by Nitrososphaeria, a class within Thaumarchaeota comprising all known ammonia-oxidizing archaea (AOA). AOA are key players in the nitrogen cycle and defining their niche specialization can help predicting effects of environmental change on these communities. However, hierarchical effects of environmental filters on AOA and the delineation of niche preferences of nitrososphaerial lineages remain poorly understood. We used phylogenetic information at fine scale and machine learning approaches to identify climatic, edaphic and geomorphological drivers of Nitrososphaeria and other archaea along a 3000 km European gradient. Only limited insights into the ecology of the low-abundant archaeal classes could be inferred, but our analyses underlined the multifactorial nature of niche differentiation within Nitrososphaeria. Mean annual temperature, C:N ratio and pH were the best predictors of their diversity, evenness and distribution. Thresholds in the predictions could be defined for C:N ratio and cation exchange capacity. Furthermore, multiple, independent and recent specializations to soil pH were detected in the Nitrososphaeria phylogeny. The coexistence of widespread ecophysiological differences between closely related soil Nitrososphaeria highlights that their ecology is best studied at fine phylogenetic scale

Left- and right-handed alpha-helical turns in homo- and hetero-chiral helical scaffolds

Proteins typically consist of right-handed alpha helices, whereas left-handed alpha helices are rare in nature. Peptides of 20 amino acids or less corresponding to protein helices do not form thermodynamically stable alpha helices in water away from protein environments. The smallest known water-stable right- (αR) and left- (αL) handed alpha helices are reported, each stabilized in cyclic pentapeptide units containing all L- or all D-amino acids. Homochiral decapeptides comprising two identical cyclic pentapeptides (αRαR or αLαL) are continuous alpha-helical structures that are extremely stable to denaturants, degradative proteases, serum, and additives like TFE, acid, and base. Heterochiral decapeptides comprising two different cyclic pentapeptides (αLαR or αRαL) maintain the respective helical handedness of each monocyclic helical turn component but adopt extended or bent helical structures depending on the solvent environment. Adding TFE to their aqueous solutions caused a change to bent helical structures with slightly distorted N-terminal αR or αL-helical turns terminated by a Schellman-like motif adjacent to the C-terminal αL or αR-turn. This hinge-like switching between structures in response to an external cue suggests possible uses in larger structures to generate smart materials. The library of left- and right-handed 1−3 turn alpha-helical compounds reported herein project their amino acid side chains into very different regions of 3D space, constituting a unique and potentially valuable class of novel scaffolds