Life Sciences Commons^™

Role Of Carotenoid Cleavage Dioxygenases In Volatile Emissions And Insect Resistance In Arabidopsis, Shailu Lakshminarayan

Electronic Thesis and Dissertation Repository

In Arabidopsis thaliana, carotenoid degradation by enzymatic oxidative cleavage is catalyzed by nine CCD and NCED enzymes; this cleavage produces an array of terpenoid products that are collectively known as apocarotenoids, which include volatile and non-volatile compounds. Previous studies on CCD1 revealed that its overexpression in A. thaliana enhances β-ionone emission and reduces damage caused by flea beetles. In consideration of these findings, I generated CCD4 and CCD8 Arabidopsis overexpression lines. Further, I characterized these overexpression lines on the basis of their carotenoid content and their volatile profiles. Surprisingly, accumulation of key carotenoids in the leaves was observed in both …

Effects Of Biodiesel Concentration On Microbial Deterioration Of Polyethylene In A Simulated Fuel Storage Tank, Juan Manuel Restrepo-Florez

Electronic Thesis and Dissertation Repository

In this study a simulated fuel storage tank was used to investigate the effect of biodiesel concentration on biodegradation of polyethylene. This research is relevant in the field of fuel storage. The simulated storage system consisted of a number of identical conical flasks. Each flask was comprised of two layers, an upper one consisting of a fuel blend of diesel with biodiesel in concentrations ranging from 0 to 100% of biodiesel and the bottom layer containing an aqueous mineral media inoculated with a community obtained from a real fuel storage facility. Polyethylene slabs cut to a specific size were immersed …

Heterologous Production And Characterization Of Cell Wall Degrading Enzymes Using Plants As A Bioreactor, Eridan Orlando Rodrigues Pereira

Electronic Thesis and Dissertation Repository

Plants are wonderful living organisms. They are able to store solar energy into carbohydrates by fixing CO₂ through photosynthesis which can be subsequently harvested and used for fuel production. However, one of the major limitations for transforming these carbohydrates into liquid fuels is the recalcitrance of the plant cell wall. Although microorganisms have evolved a series of cell wall degrading enzymes to harvest efficiently this energy and are considered the main source of these biocatalysts, harnessing these microorganisms for the production of enzymes is a costly process and a major factor limiting the commercialization of lignocellulosic biomass-to-ethanol processes. The …

Uncovering The Molecular Link Between Mir156.Spl15 And Carotenoid Accumulation In Arabidopsis, Davood Emami Meybodi

Electronic Thesis and Dissertation Repository

Carotenoid Cleavage Dioxygenases (CCDs) are an enzyme family that cleaves specific double bonds in carotenoids. MicroR156 in Arabidopsis regulates a network of genes by repressing 10 SPL genes, among which, SPL15 was found to regulate shoot branching and carotenoid accumulation. The expression of CCD1, CCD4, CCD7, CCD8, NCED2, NCED3, NCED5, NCED6, NCED9 and SPL15 was evaluated in siliques at 10 days post anthesis and in 10-day-old roots in Arabidopsis wild type, sk156 (miR156 overexpression mutant), RS105 (miR156 overexpression line), spl15 (SPL15 knockout mutant) and two 35S:SPL15 lines. Results showed that most of CCD/NCED genes were …

Role Of Branched-Chain Amino Acid Transporters In Staphylococcus Aureus Virulence, Sameha Omer

Electronic Thesis and Dissertation Repository

Branched-chain amino acids (BCAAs) act as effector molecules that signal a global transcriptional regulator, CodY, to regulate virulence factors in nutrient depleted environments. Staphylococcus aureus contains three putative BCAA transporters (BrnQ1, BrnQ2, BrnQ3) whose role in BCAA uptake is unknown. We hypothesize that BrnQ transporters are involved in BCAA uptake and contribute to virulence in S. aureus by modulating CodY activity. Results from radioactive uptake assays indicate that BrnQ1 is the predominant BrnQ transporter of isoleucine, valine and leucine. Meanwhile, BrnQ2 is more specific for isoleucine. Furthermore, only the lack of BrnQ1 hinders growth of S. aureus in chemically-defined media …

Effect Of Plant Hormones On The Production Of Biomass And Lipid In Microalgae, Malihe Mehdizadeh Allaf

Electronic Thesis and Dissertation Repository

Limited fossil fuel reserves, increasing demand for energy in all parts of the world are some driving forces to look for new sources of transportation fuels. Among different options available, microalgae are currently attracting wide interests as an alternative and renewable fuel source.

Microalgae are single cell photosynthetic organisms that are known for rapid growth and high energy content and as a part of photosynthesis; they produce oil that can be used as a feedstock for biodiesel production. Some algae strains could contain lipid up to 80% of the dry biomass. The amount of lipid production is in direct relation …

Identification Of Cyclophilin Gene Family In Soybean And Characterization Of Gmcyp1, Hemanta Raj Mainali

Electronic Thesis and Dissertation Repository

I identified members of the Cyclophilin (CYP) gene family in soybean (Glycine max) and characterized the GmCYP1, one of the members of soybean CYP. CYPs belong to the immunophilin superfamily with peptidyl-prolyl cis-trans isomerase (PPIase) activity. PPIase catalyzes the interconversion of the cis- and trans-rotamers of the peptidyl-prolyl amide bond of peptides. After extensive data mining, I identified 62 different CYP genes in soybean (GmCYP1 to GmCYP62), of which 8 are multi-domain proteins and 54 are single domain proteins. At least 25% of the GmCYP genes are expressed in soybean. GmCYP1 …

Dna Hydrolysis And Genome Editing Applications Of Giy-Yig Family Homing Endonucleases, Benjamin P. Kleinstiver

Electronic Thesis and Dissertation Repository

The ability to manipulate complex genomes in a precise manner is essential for studying biological processes in model systems, engineering plant strains for agriculture, or advancing human cellular therapies to treat diseases. Genomic alterations are most efficient when a double-strand DNA break is introduced at the loci where the modification is desired. Different classes of naturally occurring DNA endonucleases, including homing endonucleases, have therefore been explored as candidates for genome modification studies as they target long stretches of DNA. Homing endonucleases are mobile genetic elements whose biological role is to introduce site-specific double-strand breaks into naïve genomes, ultimately resulting in …

Epigenetics Of Stress Adaptation In Arabidopsis: The Case Of Histone Modifications, Behnaz Najafi Majdabadi Farahani

Electronic Thesis and Dissertation Repository

Changes in the epigenetic status of plants, which contribute to changes in gene expression, in response to abiotic stress are well documented. However, their stability and transmission to subsequent generations, and their incorporation into plant stress adaptation are still a matter for debate. Using chromatin immuno-precipitation and Next Generation Sequencing (ChIP-seq), we compared genome wide enrichment of two histone marks, H3K9ac and H3K4me2, in the progeny of salt stressed and control Arabidopsis plants. Data showed less enrichment of the H3K9ac in the chromatin of the progeny of salt stressed plants, but no changes were detected in the enrichment of the …