Regulation of RNA Polymerase II Transcription in <i>Schizosaccharomyces pombe</i> by SpELL and Associated Factor SpEAF

RNA polymerase II (pol II) synthesised RNAs encode for proteins (mRNA), aid in splicing and telomere maintenance (snRNPs), and down-regulate gene expression (microRNAs). Therefore, pol II can be a critical target for modulating differential gene expression. Understanding mechanisms that underlie the various stages of transcription will elucidate origins of gene misexpression, which can give rise to a host of human diseases. Eleven-nineteen lysine-rich in leukaemia, (ELL), affects pol II transcription. The ELL gene was initially identified as a gene translocation fusion partner of the mixed lineage leukaemia (MLL) gene in patients with acute myeloid leukaemia (I). ELL interacts with pol II in vitro, increasing the rate at which it elongates nascent transcripts (2). Two ELL-associated factors, EAFI and EAF2, bind ELL family members and act as strong positive regulators of their transcription activities (3). Although ELL and EAF orthologs have been identified in metazoan organisms, previous attempts to identify similar elongation factors in lower eukaryotes had been unsuccessful. This thesis describes the identification of two genes in the yeast Schizosaccharomyces pombe, ell I and eafl, that share some sequence similarity to highly conserved regions in ELL and EAEI/EAF2 (4). Biochemical characterisation of these gene products, SpELL and SpEAF, shows that they have similar activities to their metazoan counterparts in vitro. Using a whole genome approach, I identified genes that are likely direct targets for regulation by SpELL/SpEAF in cells. Notably, ELL and EAF functions have not been studied previously at a genomic level. One SpELL/SpEAF target, sme2, was used as a model gene to investigate how the SpELL/SpEAF complex is recruited to chromatin. Together with results of in vitro binding assays, these results suggest the SpELL/SpEAF complex is recruited to pol II via the SpELL subunit

Deuterium Abundance in the Most Metal-Poor Damped Lyman alpha System: Converging on Omega_baryons

The most metal-poor DLA known to date, at z = 2.61843 in the spectrum of the QSO Q0913+072, with an oxygen abundance only about 1/250 of the solar value, shows six well resolved D I Lyman series transitions in high quality echelle spectra recently obtained with the ESO VLT. We deduce a value of the deuterium abundance log (D/H) = -4.56+/-0.04 which is in good agreement with four out of the six most reliable previous determinations of this ratio in QSO absorbers. We find plausible reasons why in the other two cases the 1 sigma errors may have been underestimated by about a factor of two. The addition of this latest data point does not change significantly the mean value of the primordial abundance of deuterium, suggesting that we are now converging to a reliable measure of this quantity. We conclude that = -4.55+/-0.03 and Omega_b h^2 (BBN) = 0.0213+/-0.0010 (68% confidence limits). Including the latter as a prior in the analysis of the five year data of WMAP leads to a revised best-fitting value of the power-law index of primordial fluctuations n_s = 0.956+/-0.013 (1 sigma) and n_s < 0.990 with 99% confidence. Considering together the constraints provided by WMAP 5, (D/H)_p, baryon oscillations in the galaxy distribution, and distances to Type Ia supernovae, we arrive at the current best estimates Omega_b h^2 = 0.0224+/-0.0005 and n_s = 0.959+/-0.013.Comment: 13 pages, 8 Figures. Revised version following referee's comments. Accepted for publication in Monthly Notices of the Royal Astronomical Society. A few typos correcte

Copper and Stone

This thesis project is prefaced with a personal history that looks at experiences and relationships as an inspiration for creative writing. The remaining sections include original poetry that responds to family history, personal experience, and recurrent themes of war, loss, nature, and relationships. Selected literature and poetry prompts are noted from diverse styles and writers - Thoreau, Milosz, Williams, Jarrell - among others

Multiple C-Terminal Tails within a Single \u3cem\u3eE. coli\u3c/em\u3e SSB Homotetramer Coordinate DNA Replication and Repair

Escherichia coli single-stranded DNA binding protein (SSB) plays essential roles in DNA replication, recombination and repair. SSB functions as a homotetramer with each subunit possessing a DNA binding domain (OB-fold) and an intrinsically disordered C-terminus, of which the last nine amino acids provide the site for interaction with at least a dozen other proteins that function in DNA metabolism. To examine how many C-termini are needed for SSB function, we engineered covalently linked forms of SSB that possess only one or two C-termini within a four-OB-fold “tetramer”. Whereas E. coli expressing SSB with only two tails can survive, expression of a single-tailed SSB is dominant lethal. E. coli expressing only the two-tailed SSB recovers faster from exposure to DNA damaging agents but accumulates more mutations. A single-tailed SSB shows defects in coupled leading and lagging strand DNA replication and does not support replication restart in vitro. These deficiencies in vitro provide a plausible explanation for the lethality observed in vivo. These results indicate that a single SSB tetramer must interact simultaneously with multiple protein partners during some essential roles in genome maintenance

Drought-tolerant Desmodium species effectively suppress parasitic striga weed and improve cereal grain yields in western Kenya

Abstracts The parasitic weed Striga hermonthica Benth. (Orobanchaceae), commonly known as striga, is an increasingly important constraint to cereal production in sub-Saharan Africa (SSA), often resulting in total yield losses in maize (Zea mays L.) and substantial losses in sorghum (Sorghum bicolor (L.) Moench). This is further aggravated by soil degradation and drought conditions that are gradually becoming widespread in SSA. Forage legumes in the genus Desmodium (Fabaceae), mainly D. uncinatum and D. intortum, effectively control striga and improve crop productivity in SSA. However, negative effects of climate change such as drought stress is affecting the functioning of these systems. There is thus a need to identify and characterize new plants possessing the required ecological chemistry to protect crops against the biotic stress of striga under such environmental conditions. 17 accessions comprising 10 species of Desmodium were screened for their drought stress tolerance and ability to suppress striga. Desmodium incanum and D. ramosissimum were selected as the most promising species as they retained their leaves and maintained leaf function for longer periods during their exposure to drought stress conditions. They also had desirable phenotypes with more above ground biomass. The two species suppressed striga infestation, both under controlled and field conditions, and resulted in significant grain yield increases, demonstrating the incremental capability of Desmodium species in striga suppression. These results demonstrate beneficial effects of Desmodium species in enhancing cereal productivity in dry areas

Push-Pull: Chemical ecology-based integrated pest management technology

Lepidopterous stemborers, and parasitic striga weeds belonging to the family Orobanchaceae, attack cereal crops in sub-Saharan Africa causing severe yield losses. The smallholder farmers are resource constrained and unable to afford expensive chemicals for crop protection. The push–pull technology, a chemical ecology- based cropping system, is developed for integrated pest and weed management in cereal–livestock farming systems. Appropriate plants were selected that naturally emit signaling chemicals (semiochemicals). Plants highly attractive for stemborer egg laying were selected and employed as trap crops (pull), to draw pests away from the main crop. Plants that repelled stemborer females were selected as intercrops (push). The stemborers are attracted to the trap plant, and are repelled from the main cereal crop using a repellent intercrop (push). Root exudates of leguminous repellent intercrops also effectively control the parasitic striga weed through an allelopathic mechanism. Their root exudates contain flavonoid compounds some of which stimulate germination of Striga hermonthica seeds, such as Uncinanone B, and others that dramatically inhibit their attachment to host roots, such as Uncinanone C and a number of di-C-glycosylflavones (di-CGFs), resulting in suicidal germination. The intercrop also improves soil fertility through nitrogen fixation, natural mulching, improved biomass, and control of erosion. Both companion plants provide high value animal fodder, facilitating milk production and diversifying farmers’ income sources. The technology is appropriate to smallholder mixed cropping systems in Africa. Adopted by about 125,000 farmers to date in eastern Africa, it effectively addresses major production constraints, significantly increases maize yields, and is economical as it is based on locally available plants, not expensive external inputs

Guidance of B Cells by the Orphan G Protein-Coupled Receptor EBI2 Shapes Humoral Immune Responses

SummaryHumoral immunity depends on both rapid and long-term antibody production against invading pathogens. This is achieved by the generation of spatially distinct extrafollicular plasmablast and follicular germinal center (GC) B cell populations, but the signals that guide responding B cells to these alternative compartments have not been fully elucidated. Here, we show that expression of the orphan G protein-coupled receptor Epstein-Barr virus-induced gene 2 (EBI2, also known as GPR183) by activated B cells was essential for their movement to extrafollicular sites and induction of early plasmablast responses. Conversely, downregulation of EBI2 enabled B cells to access the center of follicles and promoted efficient GC formation. EBI2 therefore provides a previously uncharacterized dimension to B cell migration that is crucial for coordinating rapid versus long-term antibody responses

COMPARISON OF ORAL CLONIDINE WITH ORAL MIDAZOLAM IN MANAGING AGITATION FOLLOWING SEVOFLURANE ANESTHESIA – A PROSPECTIVE, RANDOMIZED, DOUBLE BLINDED STUDY

ABSTRACT:Objective: Emergence agitation is a major problem during recovery from anesthetic agents like sevoflurane, particularly in children. This study had compared the effects of oral clonidine with oral midazolam in reducing the incidence of emergence agitation following sevoflurane anesthesia.Methods: 50 children of ASA status I and II aged between 3-8 years were randomly allotted to one of the two groups, each group comprising 25 children. Group I children were given oral Midazolam 0.5 mg/kg and Group II children were given oral Clonidine 4 mcg/kg 30 min before the induction of anesthesia. Emergence reaction was analyzed using modified objective pain scale in all children following sevoflurane administration.Results: The total agitation score was significantly less in clonidine group in comparison to midazolam group during the first hour of post operative period (P&lt;0.05).No remarkable change in the hemodynamics or oxygen saturation was observed in both groups.Conclusion: Premedication of oral clonidine 4 microgram per kg is superior to oral midazolam 0.5 mg per kg in reducing the incidence of emergence agitation following sevoflurane anesthesia.Keywords: sevoflurane, recovery, emergence agitation, clonidine, midazolam

Role Of Bed Design Characteristics On The Effective Thermal Conductivity Of A Structured Adsorbent

This work evaluates the role of different design variables on the effective thermal conduction of a structured adsorbent bed for its possible application in a temperature swing adsorption (TSA) process. The structured adsorbent bed is represented by eight parallel layers of intercalated smooth and corrugated foils of a metal support coated with 13X zeolite resulting in the formation of parallel triangular channels. The variables investigated include the thickness of the adsorbent coating, thickness of the metal, nature of contacts between smooth and corrugated foils, type of metal, presence and magnitude of an air gap between the foils, difference in alignment of the metal foil, difference in the coating methodology and effect of different void gases. The effective thermal conductivity evaluated in this work was that obtained by modelling the heat transfer through the bed in the direction perpendicular to the foils and at steady state. This two-dimensional model representing the cross section of the bed was developed in COMSOL Multiphysics. The specific heat power at one end of the bed was defined and fixed at 500 W/m2 while the temperature of the other end was fixed at 293.15 K. The sides of the structured bed were thermally insulated. The pressure of the void gas within the channels was fixed at 1 atm, with the gas density freely adjusting with temperature and according to the ideal gas law. Depending on the design parameters the width of the bed cross section varied between 1.247 and 1.827 cm while the depth of the bed cross section was identical in all cases and equal to 0.32 cm. The results showed that the effective thermal conductivity in the direction perpendicular to the foils is significantly impacted by the conductivity of the metal, if the foils were in direct contact either via imbedding or via direct metal to metal point contacts. Under this condition, the thermal conductivity depended strongly on the conductivity of metal, and weakly on the conductivity of gas medium and all other design properties. For these metal foils in air, the thermal conductivities varied between 0.561 and 0.629 W/m/K, when the metal was stainless steel, whereas for aluminum, a value of 6.66 W/m/K was obtained. In contrast, when the foils were separated either by air gaps or by a 13X coating, the effective thermal conductivity was significantly reduced, and it depended strongly on the conductivity of the gas medium and weakly on the metal conductivity and all other design properties. For example, in air and whether the metal was stainless steel 304 or aluminum, the thermal conductivities were always around 0.090 and 0.125 W/m/K