Branch migration during Rad51-promoted strand exchange proceeds in either direction

The Saccharomyces cerevisiae Rad51 protein is important for genetic recombination and repair of DNA double-strand breaks in vivo and can promote strand exchange between linear double-stranded DNA and circular single-stranded DNA in vitro. However, unlike Escherichia coli RecA, Rad51 requires an overhanging complementary 3′ or 5′ end to initiate strand exchange; given that fact, we previously surmised that the fully exchanged molecules resulted from branch migration in either direction depending on which type of end initiated the joint molecule. Our present experiments confirm that branch migration proceeds in either direction, the polarity depending on whether a 3′ or 5′ end initiates the joint molecules. Furthermore, heteroduplex DNA is formed rapidly, first at the overhanging end of the linear double-stranded DNA’s complementary strand and then more slowly by progressive lengthening of the heteroduplex region until strand exchange is complete. Although joint molecule formation occurs equally efficiently when initiated with a 3′ or 5′ overhanging end, branch migration proceeds more rapidly when it is initiated by an overhanging 3′ end, i.e., in the 5′ to 3′ direction with respect to the single-stranded DNA.

Sequences upstream of the branch site are required to form helix II between U2 and U6 snRNA in a trans-splicing reaction

Three different base paired stems form between U2 and U6 snRNA over the course of the mRNA splicing reaction (helices I, II and III). One possible function of U2/U6 helix II is to facilitate subsequent U2/U6 helix I and III interactions, which participate directly in catalysis. Using an in vitro trans-splicing assay, we investigated the function of sequences located just upstream from the branch site (BS). We find that these upstream sequences are essential for stable binding of U2 to the branch region, and for U2/U6 helix II formation, but not for initial U2/BS pairing. We also show that non-functional upstream sequences cause U2 snRNA stem–loop IIa to be exposed to dimethylsulfate modification, perhaps reflecting a U2 snRNA conformational change and/or loss of SF3b proteins. Our data suggest that initial binding of U2 snRNP to the BS region must be stabilized by an interaction with upstream sequences before U2/U6 helix II can form or U2 stem–loop IIa can participate in spliceosome assembly.

Down-regulation of RFL, the FLO/LFY homolog of rice, accompanied with panicle branch initiation

FLORICAULA (FLO) of Antirrhinum and LEAFY (FLY) of Arabidopsis regulate the formation of floral meristems. To examine whether same mechanisms control floral development in distantly related species such as grasses, we isolated RFL, FLO-LFY homolog of rice, and examined its expression and function. Northern analysis showed that RFL is expressed predominantly in very young panicle but not in mature florets, mature leaves, or roots. In situ hybridization revealed that RFL RNA was expressed in epidermal cells in young leaves at vegetative growth stage. After the transition to reproductive stage, RFL RNA was detected in all layers of very young panicle including the apical meristem, but absent in the incipient primary branches. As development of branches proceeds, RFL RNA accumulation localized in the developing branches except for the apical meristems of the branches and secondary branch primordia. Expression pattern of RFL raised a possibility that, unlike FLO and LFY, RFL might be involved in panicle branching. Transgenic Arabidopsis plants constitutively expressing RFL from the cauliflower mosaic virus 35S promoter were produced to test whether 35S-RFL would cause similar phenotype as observed in 35S-LFY plants. In 35S-RFL plants, transformation of inflorescence meristem to floral meristem was rarely observed. Instead, development of cotyledons, rosette leaves, petals, and stamens was severely affected, demonstrating that RFL function is distinct from that of LFY. Our results suggest that mechanisms controlling floral development in rice might be diverged from that of Arabidopsis and Antirrhinum.

La formación especializada del community manager en el ámbito del estado español: análisis y propuestas

Este trabajo de investigación se encuadra en en el campo de estudio de los nuevos perfiles profesionales surgidos de la evolución de los social media, las redes sociales en Internet y la incorporación de las entidades y empresas a la sociedad digital con fines comerciales y de comunicación. Su temática central analiza una profesión de reciente aparición y en continua evolución, marcada por la innovación de las propias redes sociales para, con posterioridad, estudiar la componente de especialización profesional. Esta segunda finalidad se ha conseguido mediante el análisis de acciones formativas de posgrado y de formación complementaria, dirigidas a universitarios que han finalizado sus estudios de grado o están en proceso de finalizarlos y buscan completar los conocimientos adquiridos, con el deseo de especializar su perfil profesional orientándolo hacia la gestión de redes sociales, para adquirir mayores capacidades de empleabilidad. Para describir estos fenómenos y en especial el ámbito de la proliferación de la oferta formativa para profesionales del social media, y de manera especial del perfil del community manager, comenzó a gestarse hace tres años esta tesis doctoral, que culmina en el frontispicio del año 2015, cuando la crisis económica parece comenzar a superarse...

Manager Training and Development Strategy: A Methodology to Link Strategic Initiatives at Washington and Lee University

Washington and Lee University has developed and implemented a strategic plan and performance development initiative for 2007-2017. In concert with the strategic plan and performance development initiative, supportive manager core competencies have been identified. The deliverable for this capstone project is a documented methodology that supports the strategy for the design and implementation of a manager training and development program that ensures needed competencies are available. The author uses survey data to determine training needs and priorities and, through a review of literature, investigates effective strategies to arrive at a successful implementation methodology. The author presents findings and conclusions regarding design implementation methodology for manager training and development.

Hiring Manager Training for Strategically Selecting the Best Human Capital

The selection process is arguably the most important part of the employee life cycle in an organization, but a process often underdeveloped in many organizations. Successful selection processes can put the right people into critical positions, whereas failure to focus on selection can result in poor performance, turnover, and loss of productivity critical to the continuing success of organizations. This paper creates a model for a hiring manager training that focuses on a strategic selection process to maximize chances for successful hires. Utilizing leadership and selection models, human resources can engage hiring managers in a strategic applicant selection process as well as give tools for screening, interviewing, and selecting the best candidates for employment throughout all levels of their organization.

Tectono-sedimentary evolution of the ’Numidian Formation’ and Lateral Facies (southern branch of the western Tethys): constraints for central-western Mediterranean geodynamics

The origin of the Numidian Formation (latest Oligocene to middle Miocene), characterized by ultra-mature quartzose arenites with abundant well-rounded frosted quartz grains, remains controversial. This formation, sedimented in the external domain of the Maghrebian Flysch Basin, displays three characteristic stratigraphic members with marked longitudinal (proximal–distal) and transverse (along-chain) variations with palaeogeographical importance. The origin of the Numidian supply is related to the outward tectogenetic propagation when a forebulge evolved in the African foreland, leading to the erosion of African cratonic areas rich in quartzose arenites (Nubian Sandstone-like). The ages of the Numidian Formation checked by Betic, Maghrebian and Southern Apennine data suggest a timing for the accretionary orogenic wedge, earlier in the Betic-Rifian Arc (after middle Burdigalian), later in the Algerian-Tunisian Tell (after late Burdigalian) and afterwards in Sicily and the Southern Apennines (after Langhian). A geodynamic evolutionary model for the central-western Mediterranean is proposed.

£ taken by Branch Scholars from December 1, 1798-1800

Two-page document containing financial calculations related to Croswell's day and evening students.