Identical sequence patterns in the ends of exons and introns of human protein-coding genes

Intron splicing is one of the most important steps involved in the maturation process of a pre-mRNA. Although the sequence profiles around the splice sites have been studied extensively, the levels of sequence identity between the exonic sequences preceding the donor sites and the intronic sequences preceding the acceptor sites has not been examined as thoroughly. In this study we investigated identity patterns between the last 15 nucleotides of the exonic sequence preceding the 5' splice site and the intronic sequence preceding the 3' splice site in a set of human protein-coding genes that do not exhibit intron retention. We found that almost 60% of consecutive exons and introns in human protein-coding genes share at least two identical nucleotides at their 3' ends and, on average, the sequence identity length is 2.47 nucleotides. Based on our findings we conclude that the 3' ends of exons and introns tend to have longer identical sequences within a gene than when being taken from different genes. Our results hold even if the pairs are non-consecutive in the transcription order. (C) 2012 Elsevier Ltd. All rights reserved.

An Activity Theoretical Approach to Designing Curriculum and Instruction That Shift the Means and Ends of History Education

Reformers want history education to help students learn to engage in historical inquiry, read critically across conflicting sources, and engage in civil discussion of controversial issues. How can we help teachers and students shift the roles, norms, and activity in history classrooms to achieve these aims? An activity-theoretical framework suggests the value of explicitly attending to multiple aspects of human activity when designing and presenting reform-oriented pedagogies or curricula. Such attention increases the odds that teachers who implement new approaches or curriculum will achieve significant shifts in the means and ends of history education.

Metrizability of spaces of holomorphic functions

In this paper we prove that if U is an open subset of a metrizable locally convex space E of infinite dimension, the space H(U) of all holomorphic functions on U, endowed with the Nachbin–Coeuré topology τδ, is not metrizable. Our result can be applied to get that, for all usual topologies, H(U) is metrizable if and only if E has finite dimension. RESUMEN. En este artículo se demuestra que si U es un abierto en un espacio E localmente convexo metrizable de dimensión infinita y H(U) es el espacio de funciones holomorfas en U, entonces la topología de Nachbin-Coeuré en H(U) no es metrizable. Este resultado se utiliza para demostrar que las topologías habituales en H(U) son metrizables si y sólo si E tiene dimensión finita.

DNA double-strand break repair proteins are required to cap the ends of mammalian chromosomes

Recent findings intriguingly place DNA double-strand break repair proteins at chromosome ends in yeast, where they help maintain normal telomere length and structure. In the present study, an essential telomere function, the ability to cap and thereby protect chromosomes from end-to-end fusions, was assessed in repair-deficient mouse cell lines. By using fluorescence in situ hybridization with a probe to telomeric DNA, spontaneously occurring chromosome aberrations were examined for telomere signal at the points of fusion, a clear indication of impaired end-capping. Telomeric fusions were not observed in any of the repair-proficient controls and occurred only rarely in a p53 null mutant. In striking contrast, chromosomal end fusions that retained telomeric sequence were observed in nontransformed DNA-PKcs-deficient cells, where they were a major source of chromosomal instability. Metacentric chromosomes created by telomeric fusion became even more abundant in these cells after spontaneous immortalization. Restoration of repair proficiency through transfection with a functional cDNA copy of the human DNA-PKcs gene reduced the number of fusions compared with a negative transfection control. Virally transformed cells derived from Ku70 and Ku80 knockout mice also displayed end-to-end fusions. These studies demonstrate that DNA double-strand break repair genes play a dual role in maintaining chromosomal stability in mammalian cells, the known role in repairing incidental DNA damage, as well as a new protective role in telomeric end-capping.

Arrayed transposase-binding sequences on the ends of transposon Tn5090/Tn402

The transposon Tn5090/Tn402 encodes a 559 amino acid transposase, TniA, with a DDE motif. Gel mobility shifting and cleavage protection analysis with DNase I and hydroxyl radical probes revealed that TniA binds to multiple repeat sequences on either terminus of Tn5090/Tn402. Four of these TniA-binding 19mers occurred on the left-hand (t) end and two on the right-hand (i) end. Hydroxyl radical cleavage protection demonstrated the presence of 3–6 bp contact sequences on one face of the DNA helix. The binding pattern and organisation of repeats suggested parallels between Tn5090/Tn402 and Mu, which controls its transpositional activity in the assembly step of a higher order transpososome complex. The complex terminal structure and genes of transposase and nucleotide-binding proteins in tandem are hallmarks of the handful of Mu-like elements that are known to date.

Study of the effects of turnout design on registration accuracy of propeller meters placed in downstream ends of turnout pipes /

Mode of access: Internet.

A new treatise on chess, containing the rudiments of the game explained on scientific principles, with the best methods of playing the most brilliant openings and difficult ends of games, including numerous original positions, and a selection of fifty new chess problems.

Mode of access: Internet.

Chess problems, a collection of original positions, forming one hundred ends of games won or drawn; to which is added a selection of games, including those played between the Leeds and Liverpool clubs, with remarks.

Mode of access: Internet.

A new treatise on chess, containing the rudiments of the science, with an analysis of the best methods of playing the different openings and ends of games, including many original positions, and a selection of fifty chess problems never before printed in this country.

Mode of access: Internet.

About Homogeneous Spaces and Conditions of Completeness of Spaces

Александър В. Архангелски, Митрофан М. Чобан, Екатерина П. Михайлова - Въведени са понятията o-хомогенно пространство, lo-хомогенно пространство, do-хомогенно пространство и co-хомогенно пространство. Показано е, че ако lo-хомогенно пространство X има отворено подпространство, което е q-пълно, то и самото X е q-пълно. Показано е, че ако lo-хомогенно пространство X съдържа навсякъде гъсто екстремално несвързано подпространство, тогава X е екстремално несвързано.

Nano-silver treatments reduced bacterial colonization and biofilm formation at the stem-ends of cut gladiolus ‘Eerde’ spikes

Postharvest treatments with nano-silver (NS) alleviate bacteria-related stem blockage of some cut flowers to extend their longevity. Gladiolus (Gladiolus hybridus) is a commercially important cut flower species. For the first time, the effects of NS pulses on cut gladiolus ‘Eerde’ spikes were investigated towards reducing bacterial colonization of and biofilm formation on their stems. As compared with a deionized water (DIW) control, pulse treatments with NS at 10, 25 and 50 mg L−1 for 24 h significantly (P ≤ 0.05) prolonged the vase life of cut gladiolus spikes moved into vases containing DIW. The NS treatments enhanced floret ‘opening rate’ and ‘daily ornamental value’. Although there were no significant differences among NS treatments, a 25 mg L−1 NS pulse treatment tended to give the longest vase life and the best ‘display quality’. All NS pulse treatments significantly improved water uptake by and reduced water loss from flowering spikes, thereby delaying the loss of water balance and maintaining relative fresh weight. Fifty (50) mg L−1 NS pulse-treated cut gladiolus spikes tended to exhibit the most water uptake and highest water balance over the vase period. However, there was no significant difference between 25 and 50 mg L−1 NS pulse treatments. Observations of stem-end bacterial proliferation during the vase period on cut gladiolus spikes either with or without NS pulse treatments were performed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). As compared to the control treatment, they revealed that the 25 mg L−1 NS pulse treatment effectively inhibited bacterial colonization and biofilm formation on the stem-end cut surface and in the xylem vessels, respectively. In vitro culture of the bacterial microflora and analysis of biofilm architecture using CLSM revealed that NS treatment restricted bacterial biofilm formation. After static culture for 24 h at 35 °C with 25 mg L−1 NS in the medium, no biofilm form or structure was evident. Rather, only limited bacterial cell number and scanty extracellular polysaccharide (EPS) material were observed. In contrast, mature bacterial biofilm architecture comprised of abundant bacteria interwoven with EPS formed in the absence of NS.

Students' imaginings of spaces of learning in outdoor and environmental education

In this article, the author interrogates students’ stories about the spaces and places in a tertiary Outdoor and Environmental Education course that support and shape their environmental ethics. Drawing on a longitudinal qualitative study, she explore the ways in which particular sites of learning (outdoor, practical learning) are privileged and how particular stories of outdoor spaces get reproduced. The author employs the work of poststructuralist geography scholar Doreen Massey in her analysis to highlight the intersections between space, relations of power and identity. This analysis also underscores the simultaneity of multiple and conflicting stories around Outdoor Education’s outdoor (practical) and indoor (theoretical) learning spaces. The article concludes by drawing on Elizabeth Ellsworth’s work on anomalous places of learning to explore some of the spaces in-between the indoor/outdoor binary as a way of interrupting and re-imagining places and spaces of learning in Outdoor Education.

Lighting ambiances and materialities of wood in architecture: a comparative evaluation of the quality of spaces in relation to interior finishes

Le bois est un matériau souvent utilisé par les architectes pour améliorer l’ambiance générale d’un espace, mais peu de recherches en présentent l’impact réel du matériau sur les impressions visuelles et les effets lumineux. Cette recherche étudie l’influence de la matérialité du bois par rapport à la création d’ambiances d’éclairage spécifiques dans l’architecture. Plus particulièrement, elle se concentre sur l’impact des panneaux décoratifs en bois à générer de la diversité lumineuse dans les espaces intérieurs et son potentiel à améliorer la satisfaction environnementale et l’efficacité énergétique. La recherche utilise des maquettes à l’échelle pour leur précision dans la représentation des ambiances lumineuses d’espaces éclairés naturellement ainsi que les technologies récentes d’imagerie digitale pour capturer et analyser les résultats. La méthodologie permet la comparaison entre les différents réglages des espaces intérieurs créés par une sélection des types de matérialités du bois: la réflectance (valeur), la couleur et la réflectivité. Les modalités spatiales sont comparées en présence d’ensoleillement direct et sous des conditions de ciel couvert puisque les modèles d’éclairage et les ambiances diffèrent considérablement. Les résultats permettent d’établir une discussion sur les ambiances en termes de brillance et de contraste, sur la couleur ainsi que la répartition des zones lumineuses dans l’espace. La recherche souligne le rôle des matérialités que peuvent prendre le bois pour optimiser la diversité lumineuse et la création d’ambiances visuellement confortables, ainsi que ses possibilités d’améliorer les ambiances architecturales par rapport à la lumière.