Nucleic acids in mummified plant seeds : biochemistry and molecular genetics,of pre-Columbian maize

SummaryNucleic acids fractions were isolated from pre-Columbian maize seeds and characterized using different approaches such as polyacrylamide gel electrophoresis, anti-DNA antibody binding, HPLC fractionation, molecular hybridization with cloned genes, and DNA amplification by the polymerase chain reaction. The nucleic acids were found to be very depolymerized (≤140 base pairs in length) and composed mainly of ribosomal RNA. Despite the very low amount and degree of polymerization of seed DNA, specific maize nuclear Mul, Mu4, Mu8 and, possibly, Mu5 element components could be detected, thanks to the use of amplification systems as short as 90 bp. The results suggest that evaluation of the relative proportions of Mu-type element components and, possibly, other maize genomic components in single mummified kernels, may offer a new key to the study of ancient maize populations

Stabilization of negative capacitance in ferroelectric capacitors with and without a metal interlayer

The negative capacitance operation of a ferroelectric material is not only an intriguing material science topic, but also a property with important technological applications in nanoscale electron devices. Despite the growing interest for possible applications, the very existence of negative capacitance is still actively debated, even because experimental results for ferroelectric capacitors with or without a metal interlayer led to quite contradicting indications. Here we present a comprehensive analysis of the NC operation in ferroelectric capacitorsandprovidenewinsightsaboutthediscrepanciesobservedinexperiments. Our models duly account for the three-dimensional nature of the problem and show a good agreement with several aspects of recent experiments. Our results also demonstrate that traps at the ferroelectric-dielectric interface play an important role in the feasibility of a stable negative capacitance operation in ferroelectric capacitors

Phylogenetic position of a copper age sheep (Ovis aries) mitochondrial DNA.

Background: Sheep (Ovis aries) were domesticated in the Fertile Crescent region about 9,000-8,000 years ago. Currently, few mitochondrial (mt) DNA studies are available on archaeological sheep. In particular, no data on archaeological European sheep are available. Methodology/Principal Findings: Here we describe the first portion of mtDNA sequence of a Copper Age European sheep. DNA was extracted from hair shafts which were part of the clothes of the so-called Tyrolean Iceman or O¨ tzi (5,350 - 5,100 years before present). Mitochondrial DNA (a total of 2,429 base pairs, encompassing a portion of the control region, tRNAPhe, a portion of the 12S rRNA gene, and the whole cytochrome B gene) was sequenced using a mixed sequencing procedure based on PCR amplification and 454 sequencing of pooled amplification products. We have compared the sequence with the corresponding sequence of 334 extant lineages. Conclusions/Significance: A phylogenetic network based on a new cladistic notation for the mitochondrial diversity of domestic sheep shows that the O¨ tzi’s sheep falls within haplogroup B, thus demonstrating that sheep belonging to this haplogroup were already present in the Alps more than 5,000 years ago. On the other hand, the lineage of the O¨ tzi’s sheep is defined by two transitions (16147, and 16440) which, assembled together, define a motif that has not yet been identified in modern sheep populations

Diseño de prototipo de gancho portátil para baños públicos.

Introduction: Many times, in public restrooms there is no hook or support to hang belongings while using it, which is a problem to solve. This is the case of the University of the Coast with some of its bathrooms within the facilities, for which a design opportunity arises to create a new portable element that meets this need. Objective: The objective to be achieved is to solve practicality in bathrooms, providing a tool that facilitates the handling and use of personal possessions. The design requirements will be analyzed and established, defining the problem, and including functions that respond to comfort in these places. Methodology: A methodology was developed based on French's design process model, locating 5 main phases: Analyze the scope of the problem, generate solution concepts, represent the schemes, develop details, and validate with users to obtain feedback, making iterations throughout the process. Results: A prototype solution was obtained for the problem that is consistent, eye-catching, and meets its main objective. Conclusions: Thanks to the implementation of the design process, it was possible to provide a solution to a need identified in the environment. The product was developed following an iterative procedure with various phases expressed in the methodology, resulting in a physical prototype based on 3D printing. Although the solution is functional, some points for improvement can be considered, such as greater portability and adaptability.Introducción: Muchas veces en los baños públicos no se cuenta con algún gancho o soporte para colgar pertenecías mientras se hace uso de este, lo cual es un problema para resolver. Es el caso de la Universidad de la costa con algunos de sus baños dentro de las instalaciones, por lo cual nace una oportunidad de diseño para crear un nuevo elemento portable que supla esta necesidad. Objetivo: El objetivo a alcanzar es solucionar la practicidad en los baños, suministrando una herramienta que facilite el manejo y la utilización de posesiones personales. Se analizarán y establecerán los requerimientos de diseño, definiendo el problema e incluyendo funciones que den respuesta a la comodidad en estos lugares. Metodología: Se desarrolló una metodología con base en el modelo del proceso de diseño de French, ubicando 5 fases principales: Analizar el alcance del problema, generar conceptos de solución, representar los esquemas, desarrollar detalles, y validar con usuarios para obtener retroalimentación, haciendo iteraciones a lo largo del proceso. Resultados: Se obtuvo un prototipo solución para el problema planteado que es consistente, llamativo a la vista, y cumple con su principal objetivo. Conclusiones: Gracias a la implementación del proceso de diseño fue posible dar una solución a una necesidad identificada en el entorno. El producto fue desarrollado siguiendo un procedimiento iterativo con diversas fases expresadas en la metodología, dando como resultado un prototipo físico a base de impresión 3D. Aunque la solución es funcional, se pueden consideran algunos puntos de mejora como mayor portabilidad y adaptabilidad

Phylogenetic Position of a Copper Age Sheep (Ovis aries) Mitochondrial DNA

BACKGROUND: Sheep (Ovis aries) were domesticated in the Fertile Crescent region about 9,000-8,000 years ago. Currently, few mitochondrial (mt) DNA studies are available on archaeological sheep. In particular, no data on archaeological European sheep are available. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe the first portion of mtDNA sequence of a Copper Age European sheep. DNA was extracted from hair shafts which were part of the clothes of the so-called Tyrolean Iceman or Ötzi (5,350-5,100 years before present). Mitochondrial DNA (a total of 2,429 base pairs, encompassing a portion of the control region, tRNA(Phe), a portion of the 12S rRNA gene, and the whole cytochrome B gene) was sequenced using a mixed sequencing procedure based on PCR amplification and 454 sequencing of pooled amplification products. We have compared the sequence with the corresponding sequence of 334 extant lineages. CONCLUSIONS/SIGNIFICANCE: A phylogenetic network based on a new cladistic notation for the mitochondrial diversity of domestic sheep shows that the Ötzi's sheep falls within haplogroup B, thus demonstrating that sheep belonging to this haplogroup were already present in the Alps more than 5,000 years ago. On the other hand, the lineage of the Ötzi's sheep is defined by two transitions (16147, and 16440) which, assembled together, define a motif that has not yet been identified in modern sheep populations

Characterization of Nucleotide Misincorporation Patterns in the Iceman's Mitochondrial DNA

BACKGROUND: The degradation of DNA represents one of the main issues in the genetic analysis of archeological specimens. In the recent years, a particular kind of post-mortem DNA modification giving rise to nucleotide misincorporation ("miscoding lesions") has been the object of extensive investigations. METHODOLOGY/PRINCIPAL FINDINGS: To improve our knowledge regarding the nature and incidence of ancient DNA nucleotide misincorporations, we have utilized 6,859 (629,975 bp) mitochondrial (mt) DNA sequences obtained from the 5,350-5,100-years-old, freeze-desiccated human mummy popularly known as the Tyrolean Iceman or Otzi. To generate the sequences, we have applied a mixed PCR/pyrosequencing procedure allowing one to obtain a particularly high sequence coverage. As a control, we have produced further 8,982 (805,155 bp) mtDNA sequences from a contemporary specimen using the same system and starting from the same template copy number of the ancient sample. From the analysis of the nucleotide misincorporation rate in ancient, modern, and putative contaminant sequences, we observed that the rate of misincorporation is significantly lower in modern and putative contaminant sequence datasets than in ancient sequences. In contrast, type 2 transitions represent the vast majority (85%) of the observed nucleotide misincorporations in ancient sequences. CONCLUSIONS/SIGNIFICANCE: This study provides a further contribution to the knowledge of nucleotide misincorporation patterns in DNA sequences obtained from freeze-preserved archeological specimens. In the Iceman system, ancient sequences can be clearly distinguished from contaminants on the basis of nucleotide misincorporation rates. This observation confirms a previous identification of the ancient mummy sequences made on a purely phylogenetical basis. The present investigation provides further indication that the majority of ancient DNA damage is reflected by type 2 (cytosine-->thymine/guanine-->adenine) transitions and that type 1 transitions are essentially PCR artifacts