Use of Proteomics Tools to Investigate Protein Expression in Azospirillum brasilense

Mass spectrometry based proteomics has emerged as a powerful methodology for investigating protein expression. “Bottom up” techniques in which proteins are first digested, and resulting peptides separated via multi-dimensional chromatography then analyzed via mass spectrometry provide a wide depth of coverage of expressed proteomes. This technique has been successfully and extensively used to survey protein expression (expression proteomics) and also to investigate proteins and their associated interacting partners in order to ascertain function of unknown proteins (functional proteomics). Azospirillum brasilense is a free-living diazotrophic soil bacteria, with world-wide significance as a plant-growth promoting bacteria. Living within the rhizosphere of cereal grasses, its diverse metabolism is important for its survival in the competitive rhizospheric environment. The recently sequenced genome of strain Sp245 provided a basis for the proteome studies accomplished in this work. After initial mass spectrometer parameter optimization studies, the expressed proteomes of two strains of Azospirillum brasilense, Sp7 and Sp245, grown under both nitrogen fixing and optimal growth (non nitrogen fixing) conditions were analyzed using a bottom up proteomics methodology. Further proteome studies were conducted with A. brasilense strain Sp7 in order to ascertain the effect of one chemotaxis operon, termed Che1. In this study, proteomic surveys were conducted on two bacterial derivative strains, created earlier, which lacked either a forward signaling pathway or an adaptation pathway. The proteomic surveys conducted in this work provide a foundation for further biochemical investigations. In order to facilitate further investigation and a movement into functional proteomics, a set of destination vectors was created that contain a variety of tandem affinity tags. The addition of tandem affinity tags to a protein allow for generic purification schemes, and can facilitate future studies to investigate proteins of interest discovered in the first expression proteomic surveys of A. brasilense. Taken together, this dissertation provides a valuable data set for investigation into the physiology of A. brasilense and further provides biochemical tools for analysis of the functional protein interactions of A. brasilense cells

Theseus, the Labyrinth, and the Ball of String: Navigating the Regulatory Maze to Ensure Enforceability of Tribal Gaming Contracts, 40 J. Marshall L. Rev. 1123 (2007)

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Aggression among 216 patients with a first-psychotic episode of bipolar I disorder

Background: Aggression by patients with bipolar I disorder (BD-I) is not uncommon. Identifying potential risk factors early in the illness-course should inform clinical management and reduce risk. Methods: In a study sample of 216 initially hospitalized, first-psychotic episode subjects diagnosed with DSM-IV-TR BD-I, we identified recent (within 1 month before hospitalization) aggression by ratings on the Brief Psychiatric Rating Scale-Expanded and review of detailed clinical research records. We compared subjects with versus without aggressive behavior for associations with selected demographic and clinical factors. Results: Aggression was identified in 23/216 subjects (10.6%). It was associated significantly with recent suicide attempt (OR = 4.86), alcohol abuse (OR = 3.63), learning disability (OR = 3.14), and initial manic episode (OR = 2.59), but not with age, sex, onset-type, personality disorder, time to recovery, or functional status. Conclusions: Among first-major episode BD-I patients with psychotic features, recent serious aggression towards others was identified in 10.6%. The odds of aggression increased by 4.9-times in association with a recent suicide attempt, more than 3-times with alcohol-abuse or learning disability, and by 2.6-times if the episode polarity was manic. The findings encourage closer management of alcohol misuse, suicide risk, and manic symptoms, and early detection of learning problems in BD-I patients

Sex-Specific Impacts of Exercise on Cardiovascular Remodeling

Cardiovascular diseases (CVD) remain the leading cause of death in men and women. Biological sex plays a major role in cardiovascular physiology and pathological cardiovascular remodeling. Traditionally, pathological remodeling of cardiovascular system refers to the molecular, cellular, and morphological changes that result from insults, such as myocardial infarction or hypertension. Regular exercise training is known to induce physiological cardiovascular remodeling and beneficial functional adaptation of the cardiovascular apparatus. However, impact of exercise-induced cardiovascular remodeling and functional adaptation varies between males and females. This review aims to compare and contrast sex-specific manifestations of exercise-induced cardiovascular remodeling and functional adaptation. Specifically, we review (1) sex disparities in cardiovascular function, (2) influence of biological sex on exercise-induced cardiovascular remodeling and functional adaptation, and (3) sex-specific impacts of various types, intensities, and durations of exercise training on cardiovascular apparatus. The review highlights both animal and human studies in order to give an all-encompassing view of the exercise-induced sex differences in cardiovascular system and addresses the gaps in knowledge in the field

d0 Perovskite-Semiconductor Electronic Structure

We address the low-energy effective Hamiltonian of electron doped d0 perovskite semiconductors in cubic and tetragonal phases using the k*p method. The Hamiltonian depends on the spin-orbit interaction strength, on the temperature-dependent tetragonal distortion, and on a set of effective-mass parameters whose number is determined by the symmetry of the crystal. We explain how these parameters can be extracted from angle resolved photo-emission, Raman spectroscopy, and magneto-transport measurements and estimate their values in SrTiO3

Uniaxial strain induced band splitting in semiconducting SrTiO₃

We use angle-resolved photoemission spectroscopy to study the influence of mechanically induced uniaxial strain on the electronic structure of the oxide semiconductor SrTiO3. We observe an orbital splitting between the Ti 3dyz and 3dxy bands, which are degenerate when unperturbed. Using the k·p method, we qualitatively explain the direction and the size of the observed energy splitting. Our comprehensive understanding of band splitting explains the strain induced mobility enhancement of electron-doped SrTiO33 in terms of band degeneracy breaking and reduced interband scattering. Our approach can be extended to differently strained oxide systems