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Full-Text Articles in Life Sciences

Investigating The Role Of Protein Phosphatase 2a In The Salt Stress Response In Arabidopsis Thaliana, Daniel J. Dirocco Jan 2020

Investigating The Role Of Protein Phosphatase 2a In The Salt Stress Response In Arabidopsis Thaliana, Daniel J. Dirocco

Honors Theses and Capstones

Protein Phosphatase 2A (PP2A) is a ubiquitous enzyme in eukaryotes that regulates a large array of cellular signaling processes. PP2A is composed of three subunits: catalytic C subunit, regulatory B subunit, and scaffolding/regulatory A subunit. In Arabidopsis thaliana, the A subunit has three isoforms - A1, A2, and A3 - that are highly conserved at the protein level, indicating that these proteins may be functionally interchangeable. In comparison to wildtype plants, seedlings with a mutation in the A1 gene have roots with obvious root cell file rotation or twisting under conditions of moderate salt stress. Twisted root cells result in a ...


Root Hair Single Cell Type Specific Profiles Of Gene Expression And Alternative Polyadenylation Under Cadmium Stress, Jingyi Cao, Congting Ye, Guijie Hao, Carole Dabney-Smith, Arthur G. Hunt, Qingshun Q. Li May 2019

Root Hair Single Cell Type Specific Profiles Of Gene Expression And Alternative Polyadenylation Under Cadmium Stress, Jingyi Cao, Congting Ye, Guijie Hao, Carole Dabney-Smith, Arthur G. Hunt, Qingshun Q. Li

Plant and Soil Sciences Faculty Publications

Transcriptional networks are tightly controlled in plant development and stress responses. Alternative polyadenylation (APA) has been found to regulate gene expression under abiotic stress by increasing the heterogeneity at mRNA 3′-ends. Heavy metals like cadmium pollute water and soil due to mining and industry applications. Understanding how plants cope with heavy metal stress remains an interesting question. The Arabidopsis root hair was chosen as a single cell model to investigate the functional role of APA in cadmium stress response. Primary root growth inhibition and defective root hair morphotypes were observed. Poly(A) tag (PAT) libraries from single cell types ...


Isoprenyl Diphosphate Synthases: The Chain Length Determining Step In Terpene Biosynthesis, Raimund Nagel, Axel Schmidt, Reuben J. Peters Jan 2019

Isoprenyl Diphosphate Synthases: The Chain Length Determining Step In Terpene Biosynthesis, Raimund Nagel, Axel Schmidt, Reuben J. Peters

Biochemistry, Biophysics and Molecular Biology Publications

Main Conclusion

This review summarizes the recent developments in the study of isoprenyl diphosphate synthases with an emphasis on analytical techniques, product length determination, and the physiological consequences of manipulating expression in planta.

The highly diverse structures of all terpenes are synthesized from the five carbon precursors dimethylallyl diphosphate and a varying number of isopentenyl diphosphate units through 1’-4 alkylation reactions. These elongation reactions are catalyzed by isoprenyl diphosphate synthases (IDS). IDS are classified depending on the configuration of the ensuing double bond as trans- and cis-IDS. In addition, IDS are further stratified by the length of their ...


Using Arabidopsis Mesophyll Protoplasts To Study Unfolded Protein Response Signaling, Yan Bao, Diane C. Bassham Dec 2018

Using Arabidopsis Mesophyll Protoplasts To Study Unfolded Protein Response Signaling, Yan Bao, Diane C. Bassham

Genetics, Development and Cell Biology Publications

Various environmental stresses or artificial reagents can trigger unfolded protein accumulation in the endoplasmic reticulum (ER) due to the folding capacity of the ER being exceeded. This is termed ER stress, and triggers the unfolded protein response (UPR). Assays for activation of the UPR in plants include Tunicamycin (Tm)- or dithiothreitol (DTT)-mediated root growth inhibition, analysis of splicing of the UPR-responsive transcription factor bZIP60 (basic Leucine Zipper Domain 60), and upregulation of relevant UPR genes. We provide here a quick and robust method to detect UPR signaling in Arabidopsis thaliana protoplasts. This assay can also be applied to other ...


Ire1b Degrades Rnas Encoding Proteins That Interfere With The Induction Of Autophagy By Er Stress In Arabidopsis Thaliana, Yan Bao, Yunting Pu, Xiang Yu, Brian D. Gregory, Renu Srivastava, Stephen H. Howell, Diane C. Bassham Aug 2018

Ire1b Degrades Rnas Encoding Proteins That Interfere With The Induction Of Autophagy By Er Stress In Arabidopsis Thaliana, Yan Bao, Yunting Pu, Xiang Yu, Brian D. Gregory, Renu Srivastava, Stephen H. Howell, Diane C. Bassham

Genetics, Development and Cell Biology Publications

Macroautophagy/autophagy is a conserved process in eukaryotes that contributes to cell survival in response to stress. Previously, we found that endoplasmic reticulum (ER) stress induces autophagy in plants via a pathway dependent upon AT5G24360/IRE1B (INOSITOL REQUIRING 1–1), an ER membrane-anchored factor involved in the splicing of AT1G42990/BZIP60 (basic leucine zipper protein 60) mRNA. IRE1B is a dual protein kinase and ribonuclease, and here we determined the involvement of the protein kinase catalytic domain, nucleotide binding and RNase domains of IRE1B in activating autophagy. We found that the nucleotide binding and RNase activity of IRE1B, but not ...


Identification And Characterization Of Salinity Tolerance Genes By Activation Tagging In Arabidopsis, Jawaher Alkahtani Aug 2018

Identification And Characterization Of Salinity Tolerance Genes By Activation Tagging In Arabidopsis, Jawaher Alkahtani

Theses and Dissertations

Salinity often affects irrigated areas in arid and semi-arid regions of the world. The existence and accumulation of soluble salts in the soil layers limit the growth of crops essential for our food. Salt stress dramatically affects plant growth, plant development, as well as crop yield. Arabidopsis thaliana is the plant model that provides a comprehensive knowledge of plant development, genetics and physiology, and response to abiotic stresses such as salinity. The redundancy of genes due to duplication, even in the simple model genome of Arabidopsis, limits the value of knockout (KO) mutagenesis to provide complete information on gene function ...


Interplay Of Dgat1, Pdat1 And Dgat2 Enzymes In Plant Triacylglycerol Assembly, Anushobha Regmi May 2018

Interplay Of Dgat1, Pdat1 And Dgat2 Enzymes In Plant Triacylglycerol Assembly, Anushobha Regmi

Master's Theses

Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the transesterification of fatty acid from acyl-CoA to diacylglycerol (DAG) forming triacylglycerol (TAG, a.k.a oils and fats). Most plants have at least two unrelated DGAT genes, DGAT1 and DGAT2. Plants predominantly express only one during oil synthesis; the reason, however is not clear. A few studies have indicated that each enzyme prefers DAG and acyl-CoA substrates with different fatty acid compositions. Industrially desirable seed oil composition can be obtained through genetic engineering by replacing the endogenous enzyme with one that has different substrate selectivity. In Arabidopsis thaliana, DGAT1 and another unrelated enzyme PDAT1 ...


Enhancing Resolution Of Natural Methylome Reprogramming Behavior In Plants, Robersy Sanchez, Xiaodong Yang, Hardik Kundariya, Jose R. Barreras, Yashitola Wamboldt, Sally A. Mackenzie Jan 2018

Enhancing Resolution Of Natural Methylome Reprogramming Behavior In Plants, Robersy Sanchez, Xiaodong Yang, Hardik Kundariya, Jose R. Barreras, Yashitola Wamboldt, Sally A. Mackenzie

Agronomy & Horticulture -- Faculty Publications

We have developed a novel methylome analysis procedure, Methyl-IT, based on information thermodynamics and signal detection. Methylation analysis involves a signal detection problem, and the method was designed to discriminate methylation regulatory signal from background noise induced by thermal fluctuations. Comparison with three commonly used programs and various available datasets to furnish a comparative measure of resolution by each method is included. To confirm results, methylation analysis was integrated with RNAseq and network enrichment analyses. Methyl-IT enhances resolution of genome methylation behavior to reveal network-associated responses, offering resolution of gene pathway influences not attainable with previous methods.


Tor-Dependent And -Independent Pathways Regulate Autophagy In Arabidopsis Thaliana, Yunting Pu, Xinjuan Luo, Diane C. Bassham Jul 2017

Tor-Dependent And -Independent Pathways Regulate Autophagy In Arabidopsis Thaliana, Yunting Pu, Xinjuan Luo, Diane C. Bassham

Genetics, Development and Cell Biology Publications

Autophagy is a critical process for recycling of cytoplasmic materials during environmental stress, senescence and cellular remodeling. It is upregulated under a wide range of abiotic stress conditions and is important for stress tolerance. Autophagy is repressed by the protein kinase target of rapamycin (TOR), which is activated in response to nutrients and in turn upregulates cell growth and translation and inhibits autophagy. Down-regulation of TOR in Arabidopsis thaliana leads to constitutive autophagy and to decreased growth, but the relationship to stress conditions is unclear. Here, we assess the extent to which TOR controls autophagy activation by abiotic stress. Overexpression ...


Myosin Xi-I Works In Tandem With A Microtubule-Associated Mechanism To Position The Nucleus In Arabidopsis Root Hairs, Ian Andrew Windham May 2017

Myosin Xi-I Works In Tandem With A Microtubule-Associated Mechanism To Position The Nucleus In Arabidopsis Root Hairs, Ian Andrew Windham

Chancellor’s Honors Program Projects

No abstract provided.


Cytosolic Acetyl-Coa Promotes Histone H3 Lysine 27 Acetylation In Arabidopsis, Chen Chen Feb 2017

Cytosolic Acetyl-Coa Promotes Histone H3 Lysine 27 Acetylation In Arabidopsis, Chen Chen

Electronic Thesis and Dissertation Repository

Acetyl-coenzyme A (acetyl-CoA) serves as a central metabolite in energy metabolism and biosynthesis. High level of acetyl-CoA can fuel the tricarboxylic acid (TCA) cycle to generate energy and store excess energy in fatty acids. Meanwhile, it also provides acetyl groups for protein acetylation, which normally occurs at the lysine or arginine residues. Acetylation regulates protein functions largely due to the change of total charges. Acetylation of histones, for example, can lead to loss of the interaction between histone and DNA, thus relaxing chromatin structure and potentially promoting gene expression. However, whether and how acetyl-CoA regulates plant chromatin remains unexplored. Here ...


Characterization Of The Cytokinin-Responsive Transcriptome In Rice, Tracy Raines, Ivory C. Blakley, Yu-Chang Tsai, Jennifer M. Worthen, José M. Franco-Zorrilla, Roberto Solano, G. Eric Schaller Dec 2016

Characterization Of The Cytokinin-Responsive Transcriptome In Rice, Tracy Raines, Ivory C. Blakley, Yu-Chang Tsai, Jennifer M. Worthen, José M. Franco-Zorrilla, Roberto Solano, G. Eric Schaller

Open Dartmouth: Published works by Dartmouth faculty

Cytokinin activates transcriptional cascades important for development and the responses to biotic and abiotic stresses. Most of what is known regarding cytokinin-regulated gene expression comes from studies of the dicotyledonous plant Arabidopsis thaliana. To expand the understanding of the cytokinin-regulated transcriptome, we employed RNA-Seq to analyze gene expression in response to cytokinin in roots and shoots of the monocotyledonous plant rice.


Iron Signaling In Arabidopsis Thaliana, Celina Abundis Nov 2016

Iron Signaling In Arabidopsis Thaliana, Celina Abundis

Masters Theses

Iron is among the essential micronutrients for all living organisms and is a cofactor for many cellular redox reactions. Although iron is a highly abundant metal element found in the earth’s crust, it is also a limiting factor in plant development when it is present as insoluble ferric oxides. Plants have evolved two strategies to acquire soluble iron referred to as Strategy I and Strategy II. Our lab has focused on the Arabidopsis thaliana double mutant ysl1ysl3. The mutants display a chlorotic phenotype and are unable to correctly respond to iron deficiency.

Grafting is a common method for joining ...


Msl1 Is A Mechanosensitive Ion Channel That Dissipates Mitochondrial Membrane Potential And Maintains Redox Homeostasis In Mitochondria During Abiotic Stress, Chun Pong Lee, Grigory Maksaev, Gregory S. Jensen, Monika W. Murcha, Margaret E. Wilson, Mark Fricker, Ruediger Hell, Elizabeth S. Haswell, A Harvey Millar, Lee J. Sweetlove Nov 2016

Msl1 Is A Mechanosensitive Ion Channel That Dissipates Mitochondrial Membrane Potential And Maintains Redox Homeostasis In Mitochondria During Abiotic Stress, Chun Pong Lee, Grigory Maksaev, Gregory S. Jensen, Monika W. Murcha, Margaret E. Wilson, Mark Fricker, Ruediger Hell, Elizabeth S. Haswell, A Harvey Millar, Lee J. Sweetlove

Biology Faculty Publications & Presentations

Mitochondria must maintain tight control over the electrochemical gradient across their inner membrane to allow ATP synthesis while maintaining a redox-balanced electron transport chain and avoiding excessive reactive oxygen species production. However, there is a scarcity of knowledge about the ion transporters in the inner mitochondrial membrane that contribute to control of membrane potential. We show that loss of MSL1, a member of a family of mechanosensitive ion channels related to the bacterial channel MscS, leads to increased membrane potential of Arabidopsis mitochondria under specific bioenergetic states. We demonstrate that MSL1 localises to the inner mitochondrial membrane. When expressed in ...


An Investigation Of The Plant Growth Promoting Abilities Of Pseudomonas Fluorescens Uw4 Under Toxic Metal Stress, Joshua J. Frank Aug 2016

An Investigation Of The Plant Growth Promoting Abilities Of Pseudomonas Fluorescens Uw4 Under Toxic Metal Stress, Joshua J. Frank

Electronic Thesis and Dissertation Repository

I investigated plant-microbe-metal interactions under metal stress. In theory, plant growth promoting rhizobacteria (PGPR) promote plant growth by reducing stress ethylene and synthesizing indole-3-acetic acid (IAA). The putative PGPR Pseudomonas fluorescens UW4 and a mutant strain that lacked an enzyme critical to the reduction of plant ethylene were studied to determine if they could promote Arabidopsis thaliana growth under cadmium and copper stress conditions. Both strains of P. fluorescens UW4 adhered to roots and synthesized IAA, and the wild-type lowered metal stress-induced ethylene in Arabidopsis, but neither strain enhanced plant growth. Wildtype P. fluorescens UW4 and its mutant had no ...


Computational Analyses Of Mrna Ribosome Loading In Arabidopsis Thaliana, Joseph Benjamin Ernest Aug 2016

Computational Analyses Of Mrna Ribosome Loading In Arabidopsis Thaliana, Joseph Benjamin Ernest

Doctoral Dissertations

Translation of mRNA into protein is a critical step in gene expression, but the principles guiding its regulation at the genome level are not completely understood. Translation can be quantified at a genome scale by measuring the ribosome loading of mRNA—the extent to which mRNA is associated with ribosomes. In this dissertation, I present investigations into how genome-wide ribosome loading is controlled in Arabidopsis thaliana. In chapter 1, I give an overview of regulation of ribosome loading and translation. In chapter 2, I present research demonstrating for the first time that genome-wide ribosome loading in plants is partially controlled ...


Searching For Potential Binding Partners Of Arabidopsis Β-Amylase2 Using Yeast 2-Hybridization, Megan E. Hines May 2016

Searching For Potential Binding Partners Of Arabidopsis Β-Amylase2 Using Yeast 2-Hybridization, Megan E. Hines

Senior Honors Projects, 2010-2019

BAM2 is a chloroplast-targeted member of the β-amylase gene family that currently has an unknown function in starch hydrolysis. Previous research indicated that BAM2 did not have significant catalytic activity, but, because the gene is highly conserved and there is a starch-excess phenotype in older plants lacking BAM2, it was hypothesized that BAM2 may instead have a regulatory function. Many regulatory proteins function by interacting with other proteins, so we wanted to test for potential protein binding partners for BAM2 using the yeast two-hybrid system. A plasmid containing the BAM2 gene from Arabidopsis thaliana was co-transformed into Y190-strain yeast (Saccharomyces ...


Identification Of N-Acylethanolamine Hydrolyzing Enzyme In Solanum Lycopersicum, Derek A. Stuffle May 2016

Identification Of N-Acylethanolamine Hydrolyzing Enzyme In Solanum Lycopersicum, Derek A. Stuffle

Undergraduate Honors Theses

N-acylethanolamines (NAEs) are fatty acid derivatives that occur naturally in plant and animal systems. In mammals, they regulate physiological functions, including neurotransmission, immune responses, vasodilation, embryo development and implantation, feeding behavior, and cell proliferation. NAEs are metabolized by fatty acid amide hydrolase (FAAH), which belongs to the amidase signature family. It is hypothesized that putative FAAH functions as the catalyst in the metabolism of N-acylethanolamine in tomato plants. To test the hypothesis, FAAH protein homologs were identified in tomato via in silico analysis. Among the six homologs identified, FAAH1 and FAAH2 were selected for further validation. This study ...


Insights Into Triterpene Metabolism In Model Monocotyledonous And Oilseed Plants Genetically Engineered With Genes From Botryococcus Braunii, Chase F. Kempinski Jan 2016

Insights Into Triterpene Metabolism In Model Monocotyledonous And Oilseed Plants Genetically Engineered With Genes From Botryococcus Braunii, Chase F. Kempinski

Theses and Dissertations--Plant and Soil Sciences

Isoprenoids are one of the most diverse classes of natural products and are all derived from universal five carbon, prenyl precursors. Squalene and botryococcene are linear, hydrocarbon triterpenes (thirty carbon compounds with six prenyl units) that have industrial and medicinal values. Squalene is produced by all eukaryotes as it is the first committed precursor to sterols, while botryococcene is uniquely produced by the green algae, Botryococcus braunii (race B). Natural sources for these compounds exist, but there is a desire for more renewable production platforms. The model plant Arabidopsis thaliana was engineered to accumulate botryococcene and squalene in its oil ...


Investigation Into The Cell Wall And Cellulose Biosynthesis In Model Species And In The C4 Model Plant Setaria Viridis, Mizuki Tateno Jan 2016

Investigation Into The Cell Wall And Cellulose Biosynthesis In Model Species And In The C4 Model Plant Setaria Viridis, Mizuki Tateno

Theses and Dissertations--Plant and Soil Sciences

A uniform feature of all plant cells is the presence of a cell wall. The cell wall functions in facilitating directional expansion and is therefore important for cell shape and morphogenesis. All plant cell walls contain cellulose microfibrils embedded in a network of polysaccharides, lignin and protein. Cellulose is evolutionarily conserved and is made by all plants as well as other members of various taxonomic kingdoms. From a human perspective, the field of renewable energy has had an ever increasing interest in using the cell wall for production of renewable platform chemicals and fuels. However, the biosynthesis of these components ...


Cytokinin Acts Through The Auxin Influx Carrier Aux1 To Regulate Cell Elongation In The Root, Ian H. Street, Dennis Matthews, Maria Yamburkenko, Ali Sorooshzadeh Jan 2016

Cytokinin Acts Through The Auxin Influx Carrier Aux1 To Regulate Cell Elongation In The Root, Ian H. Street, Dennis Matthews, Maria Yamburkenko, Ali Sorooshzadeh

Open Dartmouth: Published works by Dartmouth faculty

Hormonal interactions are crucial for plant development. In Arabidopsis, cytokinins inhibit root growth through effects on cell proliferation and cell elongation. Here, we define key mechanistic elements in a regulatory network by which cytokinin inhibits root cell elongation in concert with the hormones auxin and ethylene. The auxin importer AUX1 functions as a positive regulator of cytokinin responses in the root; mutation of AUX1 specifically affects the ability of cytokinin to inhibit cell elongation but not cell proliferation. AUX1 is required for cytokinin-dependent changes of auxin activity in the lateral root cap associated with the control of cell elongation. Cytokinin ...


A Novel Transcription Factor In Arabidopsis Thaliana Abiotic Stress Response, Achira S. Weerathunga Arachchilage Dec 2015

A Novel Transcription Factor In Arabidopsis Thaliana Abiotic Stress Response, Achira S. Weerathunga Arachchilage

University of New Orleans Theses and Dissertations

Plants respond to environmental stress by altering their gene expression. Under stress conditions some genes are activated and some genes are repressed. Even though a lot of work has been done to understand mechanisms of gene activation under abiotic stress very little information is available on how stress responsive genes are kept repressed under normal growth conditions. Recent work has revealed that plants use transcriptional repression as common mechanism of gene repression. Transcriptional repression is achieved by recruitment co-repressor complexes to the target genes. Recent studies have revealed that the co-repressor LUH complexes with SLK1 and SLK2 to silence Arabidopsis ...


Genetic Analysis Of A Non-Germinating Mutant Of Arabidopsis Thaliana, Md Jakir Hossan Aug 2015

Genetic Analysis Of A Non-Germinating Mutant Of Arabidopsis Thaliana, Md Jakir Hossan

Electronic Thesis and Dissertation Repository

Seed germination is partially controlled by plant hormone gibberellins (GAs). Chemical mutagenesis yielded an Arabidopsis thaliana mutant gm11, which has an absolute gibberellin requirement for seed germination. This mutant exhibited phenotypes of GA-rescuable dwarfs, including dark-green leaves, and reduced fertility. However, with repeated GA treatment, gm11 develops into fertile plants with a nearly wild type phenotype. Bulked-segregant analysis mapped gm11 to the bottom arm of chromosome 1, and subsequent next-generation mapping revealed that the mutation is a G → A transition in At1g79460 (GA2), creating a premature stop codon. This gene encodes an ent-kaurene synthase (KS) which catalyzes the conversion of ...


Thermodynamic Analysis Of Phenylpropanoid Pathway In Arabidopsis Thanliana, Patrick J. Ioerger, Rohit Jaini, John A. Morgan Aug 2015

Thermodynamic Analysis Of Phenylpropanoid Pathway In Arabidopsis Thanliana, Patrick J. Ioerger, Rohit Jaini, John A. Morgan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biofuels represent a renewable alternative to traditional fossil fuels. As dependence on fossil fuels rise so does the importance of improving the production of alternative fuels. Lignin poses one obstacle in the development of such alternative fuels. Its presence strengthens cell walls and hinders degradation of polysaccharides into monosaccharides, increasing cost and time while decreasing efficiency of the process. Lignin is composed of three monolignols, each of which is produced through the Phenylpropanoid pathway; a series of chemical reactions. This work aims to determine which reactions in the pathway are least thermodynamically favorable and thus most limiting. From metabolic mapping ...


Detecting Genomic Regions Responsible For Resistance In Arabidopsis, Valeria Cancino, Anjali Iyer-Pascuzzi, Rucha Karve Aug 2015

Detecting Genomic Regions Responsible For Resistance In Arabidopsis, Valeria Cancino, Anjali Iyer-Pascuzzi, Rucha Karve

The Summer Undergraduate Research Fellowship (SURF) Symposium

Ralstonia solanacearum is a soil-borne plant root colonizing pathogen and the casual agent of bacterial wilt (BW) disease. BW leads to severe yield loss in a wide variety of agricultural commodity crops, such as tomato, banana, and pepper. In this study, we look at the plant-pathogen interaction between Ralstonia solanacearum and various ecotypes of Arabidopsis thaliana with the goal of finding resistant ecotypes. To identify resistant ecotypes, seeds are first sterilized and left to soak in the dark. Then the seeds are plated on agar media, transferred to a growth chamber, and allowed to grow for 5 days. On day ...


The Argos Gene Family Functions In A Negative Feedback Loop To Desensitize Plants To Ethylene, Muneeza I. Rai, Xiaomin Wang, Derek M. Thibault, Hyo Jung Kim, Matthew M. Bombyk, Brad M. Binder, Samina N. Shakeel, G. Eric Schaller Jun 2015

The Argos Gene Family Functions In A Negative Feedback Loop To Desensitize Plants To Ethylene, Muneeza I. Rai, Xiaomin Wang, Derek M. Thibault, Hyo Jung Kim, Matthew M. Bombyk, Brad M. Binder, Samina N. Shakeel, G. Eric Schaller

Open Dartmouth: Published works by Dartmouth faculty

Ethylene plays critical roles in plant growth and development, including the regulation of cell expansion, senescence, and the response to biotic and abiotic stresses. Elements of the initial signal transduction pathway have been determined, but we are still defining regulatory mechanisms by which the sensitivity of plants to ethylene is modulated. We report here that members of the ARGOS gene family of Arabidopsis, previously implicated in the regulation of plant growth and biomass, function as negative feedback regulators of ethylene signaling. Expression of all four members of the ARGOS family is induced by ethylene, but this induction is blocked in ...


Trip: Tracking Rhythms In Plants, An Automated Leaf Movement Analysis Program For Circadian Period Estimation, Kathleen Greenham, Ping Lou, Sara E. Remsen, Hany Farid, C Robertson Mcclung May 2015

Trip: Tracking Rhythms In Plants, An Automated Leaf Movement Analysis Program For Circadian Period Estimation, Kathleen Greenham, Ping Lou, Sara E. Remsen, Hany Farid, C Robertson Mcclung

Open Dartmouth: Published works by Dartmouth faculty

Background: A well characterized output of the circadian clock in plants is the daily rhythmic movement of leaves. This process has been used extensively in Arabidopsis to estimate circadian period in natural accessions as well as mutants with known defects in circadian clock function. Current methods for estimating circadian period by leaf movement involve manual steps throughout the analysis and are often limited to analyzing one leaf or cotyledon at a time.

Methods: In this study, we describe the development of TRiP (Tracking Rhythms in Plants), a new method for estimating circadian period using a motion estimation algorithm that can ...


Descriptive Analyses Of Pollen Surface Morphologies In The Model Systems Brassica Rapa And Arabidopsis Thaliana And Three Arabidopsis Pollen Wall Mutants By Scanning Electron Microscopy, Andrew B. Kirkpatrick May 2015

Descriptive Analyses Of Pollen Surface Morphologies In The Model Systems Brassica Rapa And Arabidopsis Thaliana And Three Arabidopsis Pollen Wall Mutants By Scanning Electron Microscopy, Andrew B. Kirkpatrick

Theses and Dissertations

The mechanisms behind the construction of the pollen wall are equally elaborate and mysterious. Previous studies primarily used sectioned tissue to elucidate the events involved in proper pollen development. This study proposed and evaluated a protocol for exposing developing microspores to be examined by Scanning Electron Microscopy (SEM). Utilizing this protocol, comparative analyses of the superficial features present at the early, middle, and late tetrad as well as at released microspore stages of the model plants Brassica rapa and Arabidopsis thaliana were conducted. The utility of the technique was then evaluated through the examination of three Arabidopsis pollen wall mutants ...


Heterologous Expression Of Arabidopsis Thaliana Purple Acid Phosphatase Gene (Atpap15) In Crops For Phytoremediation Of Sites Contaminated With Excess Phosphorus, Jane Jeruto Bartonjo May 2015

Heterologous Expression Of Arabidopsis Thaliana Purple Acid Phosphatase Gene (Atpap15) In Crops For Phytoremediation Of Sites Contaminated With Excess Phosphorus, Jane Jeruto Bartonjo

Masters Theses & Specialist Projects

AtPAP15 is one of the purple acid phosphatases expressed by Arabidopsis thaliana that has been extensively studied. Purified AtPAP15 has been shown to exhibit both phytase and phosphomonoesterase activities in acidic pH with maximal activity at pH 4.5. AtPAP15 is a phosphorus starvation inducible (PSI) gene that is expressed highly during phosphorus deficient conditions. In the current study, AtPAP15 was overexpressed in Nicotiana tabaccum under cauliflower mosaic virus (CaMV35S) constitutive promoter. After PCR confirmation of the gene, plants were transferred to the greenhouse and allowed to grow in pots. The pots contained Sta-Green potting mix (Lowe’s Inc., Mooresville ...


Search For Host Factors Involved In Attachment Of Agrobacterium Tumefaciens To Plants, Anna Petrovicheva Feb 2015

Search For Host Factors Involved In Attachment Of Agrobacterium Tumefaciens To Plants, Anna Petrovicheva

Dissertations, Theses, and Capstone Projects

Agrobacterium tumefaciens is able to infect a diverse array of plants and causes crown gall disease. Typically these bacteria attach to plant roots and transform the plant cells to induce tumors. The mechanism of this attachment in the infection process is not yet fully understood. Using wild type Arabidopsis thaliana, Columbia-0, and several Arabidopsis mutant lines as a binding target, we screened for A. thaliana mutants with altered adhesion.

The A. thaliana mutant lines were selected in The Arabidopsis Information Resource (TAIR) according to possible location of the resulting protein and similarity to known transformation mutants. Of these mutants nine ...