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INVESTIGATING THE CHLAMYDOMONAS REINHARDTII CALVIN CYCLE ENZYME GENES FBP1 AND SBP1: REGULATION AND EFFECT OF OVEREXPRESSION ON GROWTH
No full textMicroalgae have great potential for generating biofuels, pharmaceuticals, and other commercially valuable products. The goal of this thesis project was to improve this potential by investigating the expression and function of two key Calvin cycle enzymes in Chlamydomonas reinhardtii. Overexpression of sedoheptulose-1,7-bisphosphatase (SBPase) and fructose-1,6-bisphosphatase (FBPase) improves carbon fixation and growth rate in higher plants, but nothing has been reported regarding the role of these enzymes in photosynthetic output and biomass in C. reinhardtii, a model green alga. I first set out to determine how overexpression of C. reinhardtii SBPase affects Chlamydomonas growth by making nuclear transgenic lines expressing the SBPase-encoding gene SBP1 under control of the HSP70A/RBCS2 promoter and RBCS2 3'UTR. One transgenic line that overexpressed SBPase showed a promising result by reaching the exponential and stationary growth phases faster than the control strain, but expression of transgenic SBPase in this strain diminished significantly within 6 months, so I next set out to overexpress SBP1 and the FBPase encoding gene (FBP1) directly in the chloroplast, to avoid the possibility of gene silencing. To this end, I generated new chloroplast expression vectors with C. reinhardtii FBP1 and SBP1 coding sequences synthesized with C. reinhardtii chloroplast codon-bias and flanked with 5'psbD and 3'psbA regulatory sequences. The FBP1 vector integrated properly into the chloroplast genome and all FBP1 transformants tested accumulated ~4-fold increased levels of FBPase protein and 1.5-fold increased levels of FBPase activity; unfortunately, however, none of the SBP1 transformants expressed SBPase protein. Surprisingly, the FBPase-overexpressing transformants did not grow faster than the wild type, and in fact under mixotrophic conditions with 5% CO2 they grew more slowly and reached a maximum cell density that was 1.5-fold lower than the wild type did, and under photoautotrophic conditions they grew more slowly and reached maximum cell densities that were 1.4-fold lower (atmospheric CO2) and 1.7-fold lower (5% CO2) than the wild type. To learn more about regulation of FBP1 and SBP1 mRNA and FBPase and SBPase protein levels I cultured C. reinhardtii cells photoautotrophically under 12 hour light:12 hour dark conditions and analyzed mRNA levels by RT-qPCR and protein by western blot. I found FBP1 and SBP1 transcripts to be highly inducible by light, up to ~8 and ~9 fold, respectively, while FBPase and SBPase protein levels were only modestly elevated in the light ~2.5 and ~6 fold, respectively. So in conclusion, I determined that Chlamydomonas FBP1 and SBP1 appear to be light-regulated genes, that overexpressing SBPase might be a promising strategy for improving microalgal growth, but that overexpression of FBPase has a neutral or detrimental effect on growth and biomass productivity in C. reinhardtii, depending on growth conditions
Polarized Imaging Nephelometer Development and Applications on Aircraft
No full textSatellite remote sensing is the only method that is able to measure climate forcing atmospheric constituents on a global scale. Aerosols have large impacts on climate, through influencing radiation directly and through their effects on clouds. Remote sensing algorithms that deduce aerosol properties from satellite measurements of scattered sunlight rely on information about scattering patterns of aerosols. Chapter 1 places the work in context through a literature survey, and introduces and clarifies theoretical constructs necessary for understanding the remaining chapters. In order to improve our understanding of light scattering by aerosol particles, and to enable routine in situ airborne measurements of aerosol light scattering to calibrate and validate satellite algorithms, at LACO (Laboratory for Aerosols Clouds and Optics) we have developed an instrument called the Polarized Imaging Nephelometer (PI-Neph). We designed and built the portable PI-Neph instrument at UMBC (University of Maryland, Baltimore County); it directly measures the ambient volume scattering coefficient and the phase matrix elements P11, phase function, and -P12/P11, polarized phase function. Chapter 2 introduces the PI-Neph instrument, while chapter 3 lays out the calibration and data reduction algorithm. The PI-Neph employs illuminating lasers and polarization control, sampling of ambient air through an inlet, and wide field of view detection of scattered light in a scattering angle range of 3� to 176�. The instrument does not employ any moving parts, therefore it is robust and fast enough for airborne measurements. The PI-Neph first measured at a laser wavelength of 532nm, and was first deployed successfully in 2011 aboard the B200 aircraft of NASA Langley during the DEVOTE (Development and Evaluation of satellite ValidatiOn Tools by Experiments) project. In 2013, we upgraded the PI-Neph to measure at 473nm, 532nm, and 671nm nearly simultaneously. LACO has deployed the PI-Neph on a number of airborne field campaigns aboard three different NASA aircraft. This dissertation describes the PI-Neph instrument, the measurement approach, algorithm, and calibrations. Chapter 4 is a validation and error analysis case study, which quantifies the exceptionally good agreement of artificial polystyrene sphere data with Mie theory. The PS sphere validation data was collected during the 2012 deployment for the Deep Convective Clouds and Chemistry (DC3) field campaign. Residuals between Mie fit and PS data (angular mean and population standard deviation) in case of the cross fits were the following. The differences of P11 data and P11 fit (predicted by fit to -P12/P11), relative to the P11 data, was -1.9% � 5.5%. The differences of -P12/P11 data versus -P12/P11 fit (predicted by the fit to P11) was 0.028 � 0.062. Chapter 4 also quantifies the P11 and -P12/P11 calibration errors through a Monte Carlo simulation. At an ambient aerosol scattering coefficient of 100 Mm-1, it is estimated that the PI-Neph will measure P11 (at individual scattering angles) with relative systematic error of approximately 2.3%, and -P12/P11 with absolute systematic error of approximately 0.033. Chapter 5 presents highlights from field measurements. The DEVOTE project enabled the initial PI-Neph results, such as scattering coefficient validation via comparison to other measurements, comparison of polystyrene sphere data to Mie theory, a comparison to AERONET derived phase function, and retrieval of microphysical properties of aerosols in collaboration with Dr. Oleg Dubovik. Chapter 5 also provides an overview of DC3 data, an assessment of data quality, and quantifications of PI-Neph capabilities and noise levels. This dissertation demonstrates the capability of the PI-Neph to measure ambient levels of aerosols down to 10 Mm-1, by measurement examples from the DEVOTE and DC3 aircraft deployments. As a conclusion, an itemized list of accomplishments is given in chapter 6, along with promising future research directions
RECONSTRUCTING THE EVOLUTIONARY HISTORY OF DARTERS (PERCIDAE: ETHEOSTOMATINAE): EPIGENETIC DIVERGENCE AS A FIRST STEP IN SPECIATION
No full textThis doctoral research reconstructs the evolutionary history and investigates the possibility of changes in gene expression, rather than nucleotide sequence, being a first step in speciation in the second most speciose group of freshwater fishes in North America. To gain a better understanding of the incredible diversity in this group of fishes known as darters (Percidae: Etheostomatinae), I first determine evolutionary relationships among 69 and then 101 different species representing four genera of darters using a genome-scan approach known as AFLP. Prior to this work, AFLPs had only been used for recent divergences, with the oldest reconstruction dating to approximately 15 million years. In silico studies had predicted that increased homoplasy would weaken the utility of AFLPs in reconstructing ancient evolutionary relationships. We found that dense taxon sampling increased accuracy and resolution in this group of fishes. We were able to resolve problematic nodes and reconstruct the evolutionary history of darters with moderate to strong statistical support at ancient divergences (>25 mya) and thus champion this method for deeper relationships. In addition, we were able to propose a new taxonomic classification of darters based on our and other recent phylogenies. Phylogenetic reconstruction revealed a large amount of interspecific genetic diversity in this group of fishes. This finding led us to question whether fast-evolving changes in gene expression via changes to the methylome, rather than nucleotide sequence, could initiate speciation in this group of fishes. We investigated whether epigenetic divergence acts as a first step in speciation in Etheostoma, a genus of darters. Using Methyl-Sensitive Amplified Polymorphisms (MSAP), we analyzed population structure and differentiation in the methylome and genome across 5 populations of E. olmstedi (the tessellated darter) in the Patuxent River and 6 populations in the Potomac River in Maryland, USA. We predicted that epigenetic variation would be greater than genetic variation both within and between populations, with populations showing greater differentiation in their methylomes compared to their genomes. We also investigated the relationship between genetic divergence, epigenetic divergence, and the strength of various reproductive barriers across more distantly related, geographically isolated species in the subgenera Ulocentra, Etheostoma and Nanostoma. Since previous studies have shown behavioral isolation to be the strongest reproductive barrier between darter species, we predicted that behavioral isolation would be better predicted by epigenetic as compared to genetic differences. Our results indicate that the methylome is indeed changing faster than the nucleotide sequence across all levels of divergence, and that epigenetic divergence better predicts behavioral reproductive isolation than genetic divergence, supporting the hypothesis that epigenetic divergence can act as a first step in speciation in this group
Development of a Geared Infinitely Variable Transmission
No full textIn this work, a Geared Infinitely Variable Transmission (GIVT) which uses gears to transfer torque rather than frictional components is detailed. A comparison is made to existing continuously variable and infinitely variable transmission technology and a description of function in past and present GIVT designs is presented. The new GIVT features non-circular gearing and a scotch yoke mechanism to achieve zero speed fluctuation and avoid losses due to torque recirculation. A functioning prototype was designed and manufactured to test the performance of the scotch yoke mechanism. The theoretical efficiency was calculated and reported. New equations were derived to analyze the frictional power loss of a rack and pinion gear mesh, something which has been missing in gear design literature to date. The prototype efficiency was measured and compared to the theoretical efficiency. Using the theoretical and experimental results, several changes are proposed which will improve the performance and efficiency of the GIVT
A Semantic and Collaborative Approach to Community Health-Care
No full textCommunity Health Workers (CHWs) are an integral part of health-care in underserved or un-served areas. They act as liaisons between health-care providers and patients in communities. They collect information about illnesses, provide preventive and curative care and, report emergency cases to health center. However, the lack of information sharing and training support impedes the effectiveness of CHWs and their ability to correctly refer patients. We propose and describe a system for mobile and wearable computing devices called Remedy which assists CHWs in decision making and facilitates collaboration among them. Remedy can infer possible diseases and treatments by representing the diseases, their symptoms, and patient context in OWL ontologies and by reasoning over this model. The use of semantic representation of data makes it easier to share knowledge such as disease, symptom, diagnosis guidelines, and demography related information, between various personnel involved in health-care (e.g., CHWs, patients, health-care providers). We describe the Remedy system with the help of a motivating community health-care scenario and present an Android prototype for smart phones and Google Glass
Be Careful Out There
No full textGabriela_Kostadinova__Be_Careful_Out_There_February_21__2014_at_1057AMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Niteowl
No full textHenry_Aragoncillo__Niteowl_March_30__2014_at_0512PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Untitled [Nurses in hospital nursery]
No full textJenna_Colhouer_Kannapolis__NC_February_23__2014_at_1256AMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Baltimore Blue Light Special Broadway Recreational Pier now defunct
No full textJohn_Deamond__Montgomery_College__Instructional_Lab_Coordinator__Baltimore_Blue_Light_Special_Broadway_Recreational_Pier__now_defunct__February_22__2014_at_0723PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
My Father At Work X Ray Film
No full textJohn_Stavas__VCU_Arts_Richmond__VA__My_Father_At_Work__X_Ray_Film__January_28__2014_at_0431PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe