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Activity Of The Beta-Cyanoalanine Synthase Pathway Is Associated With The Response To Abiotic Stress By Arabidopsis Thaliana., Marylou Machingura Dec 2012

Activity Of The Beta-Cyanoalanine Synthase Pathway Is Associated With The Response To Abiotic Stress By Arabidopsis Thaliana., Marylou Machingura

Dissertations

Cyanide is produced throughout a plant's life cycle alongside the hormone ethylene by oxidation of 1-aminocyclopropane-1-carboxylic acid. Production increases during certain developmental stages such as seed germination, seedling elongation, fruit ripening and senescence. Abiotic stresses increase ethylene production giving rise to `stress cyanide'. Cyanide also comes from metabolism of cyanogenic compounds. Cyanide is however, a toxic chemical which readily binds to metallo-enzymes inhibiting primary metabolic processes. Plants have mechanisms to maintain cyanide homeostasis such as the β-cyanoalanine pathway whereby cysteine reacts with cyanide forming β--cyanoalanine, mediated by β-cyanoalanine synthase and cysteine synthase. A dual nitrilase 4 enzyme then converts the …


Expression Of Recombinant Earli1, A Hybrid Proline-Rich Protein Of Arabidopsis, In Escherichia Coli And Its Inhibition Effect To The Growth Of Fungal Pathogens And Saccharomyces Cerevisiae, Lan Li, Chen Zhang, Dan Xu, Michael Schläppi, Zi-Qin Xu Sep 2012

Expression Of Recombinant Earli1, A Hybrid Proline-Rich Protein Of Arabidopsis, In Escherichia Coli And Its Inhibition Effect To The Growth Of Fungal Pathogens And Saccharomyces Cerevisiae, Lan Li, Chen Zhang, Dan Xu, Michael Schläppi, Zi-Qin Xu

Biological Sciences Faculty Research and Publications

EARLI1 is an Arabidopsis gene with pleiotropic effects previously shown to have auxiliary functions in protecting plants against freezing-induced cellular damage and promoting germinability under low-temperature and salinity stresses. Here we determined whether recombinant EARLI1 protein has anti-fungal activity. Recombinant EARLI1 protein lacking its signal peptide was produced in Escherichia coli BL21(DE3) using isopropyl β-d-1-thiogalactopyranoside (IPTG) induction and the prokaryotic expression vector pET28a. Expression of EARLI1 was analyzed by Western blotting and the protein was purified using affinity chromatography. Recombinant EARLI1 protein was applied to fungal cultures of Saccharomyces cerevisiae, Botrytis cinerea and Fusarium oxysporum, and membrane permeability …


Evidence For An Epigenetic Mechanism By Which Hsp90 Acts As A Capacitor For Morphological Evolution, Vincent E. Sollars, Xiangyi Lu, Li Xiao, Xiaoyan Wang, Mark D. Garfinkel, Douglas M. Ruden Aug 2012

Evidence For An Epigenetic Mechanism By Which Hsp90 Acts As A Capacitor For Morphological Evolution, Vincent E. Sollars, Xiangyi Lu, Li Xiao, Xiaoyan Wang, Mark D. Garfinkel, Douglas M. Ruden

Vincent E Sollars

Morphological alterations have been shown to occur in Drosophila melanogaster when function of Hsp90 (heat shock 0-kDa protein 1α, encoded by Hsp83) is compromised during development1. Genetic selection maintains the altered phenotypes in subsequent generations1. Recent experiments have shown, however, that phenotypic variation still occurs in nearly isogenic recombinant inbred strains of Arabidopsis thaliana2. Using a sensitized isogenic D. melanogaster strain, iso-KrIf-1, we confirm this finding and present evidence supporting an epigenetic mechanism for Hsp90’s capacitor function, whereby reduced activity of Hsp90 induces a heritably altered chromatin state. The altered chromatin state is evidenced by ectopic expression of the morphogen …


The Analysis Of The Expression And Phenotype Of The At3g02400 Gene In Arabidopsis Thaliana, Will Gray Aug 2012

The Analysis Of The Expression And Phenotype Of The At3g02400 Gene In Arabidopsis Thaliana, Will Gray

Theses and Dissertations

The involvement of several genes in DNA repair in animals and bacteria, and the induced expression of At3G02400 by Mitomycin C, suggest that this gene is involved in DNA repair in plants. I have tested this hypothesis by studying the regulation of its expression and identifying the function of this gene. To study the expression of this gene, I used a reporter line and bio-computing tools. To identify the function of the gene, I have isolated two T-DNA mutants and screened Targeting Induced Local Lesions in Genomes (TILLING) mutants. T-DNA mutagenesis is the process of inserting transfer DNA into the …


The Effects Of Cytokinin On The Transcriptional Regulation Of Pin Expression In Arabidopsis Thaliana, Elizabeth Burgess Jul 2012

The Effects Of Cytokinin On The Transcriptional Regulation Of Pin Expression In Arabidopsis Thaliana, Elizabeth Burgess

Honors Theses and Capstones

The processes of cell division and differentiation are critical to the development of any multicellular organism. During the formation of plant roots these processes take place at a region of the root tip called the meristem. Cytokinin and auxin are two plant growth hormones that influence this process. Although these two growth hormones are both necessary they also appear in many ways to have an antagonistic relationship. As meristematic root cells undergo differentiation they cease dividing. It has been proposed that the size of the root meristem and thus the overall rate of root growth are determined by the balance …


Create The Scene And Watch The Show Unfold: Following Vegetative To Embryonic Developmental Transitions By Over-Expressing Lec2 In Leaves Of Arabidopsis Thaliana, Mistianne Feeney Jun 2012

Create The Scene And Watch The Show Unfold: Following Vegetative To Embryonic Developmental Transitions By Over-Expressing Lec2 In Leaves Of Arabidopsis Thaliana, Mistianne Feeney

Electronic Thesis and Dissertation Repository

During seed development, the lytic vacuole (LV) is replaced by a protein storage vacuole (PSV) which specializes in accumulating seed storage proteins (SSPs). As seed protein reserves are mobilized upon germination, the PSV is once again replaced by the LV which takes on different roles in vegetative tissues. Cellular events occurring during these developmental transitions are not well understood, particularly, the transition between vacuole types. This research investigates whether PSVs can exist in leaves. To study vacuole transitions in leaves, an Arabidopsis thaliana line over-expressing the LEAFY COTYLEDON2 (LEC2) transcription factor was used. LEC2 is a master regulator of embryogenesis …


Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser May 2012

Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser

Lawrence University Honors Projects

Plants contain innate immune systems that deter pathogen infection. Pattern recognition receptors bind microbe-associated molecular patterns (MAMPs), triggering immunity. MAMPs are proteins exclusive to pathogens that are typically indispensable for their survival. For this reason, MAMPs cannot be mutated or removed without causing pathogen death. However, this does not necessitate constitutive expression of MAMPs. In this study, the MAMP response of Arabidopsis thaliana was utilized to determine differential detection of MAMPs expressed by Pseudomonas syringe pv. tomato DC3000 when pretreated with A. thaliana. Results demonstrated that more MAMPs are detected when P. syringae had previously encountered A. thaliana, …


Automation Of The Registration Of Range Plant Images Using Geomagic Studio, Quazi M. Akter Apr 2012

Automation Of The Registration Of Range Plant Images Using Geomagic Studio, Quazi M. Akter

Electronic Thesis and Dissertation Repository

As plant science advances, the quantitative measurement of 3D plant growth has become an essential tool to evaluate the growth performance of genetically modified seeds or plants. In the past, “wet volumes” had been used to quantitatively measure plant growth which result in the destruction of the plants. Other traditional methods like interferometry methods or mechanical methods are also inefficient because they are either invasive or unable to provide sufficient growth information of the plant body. On the other hand, computer vision methods, especially optical and range flow techniques, are non-contact, more accurate, and relatively less expensive. But they require …


Revised Selection Criteria For Candidate Restriction Enzymes In Genome Walking, Ali Taheri, Stephen J. Robinson, Isobel Parkin, Margaret Y. Gruber Apr 2012

Revised Selection Criteria For Candidate Restriction Enzymes In Genome Walking, Ali Taheri, Stephen J. Robinson, Isobel Parkin, Margaret Y. Gruber

Agricultural and Environmental Sciences Faculty Research

A new method to improve the efficiency of flanking sequence identification by genome walking was developed based on an expanded, sequential list of criteria for selecting candidate enzymes, plus several other optimization steps. These criteria include: step (1) initially choosing the most appropriate restriction enzyme according to the average fragment size produced by each enzyme determined using in silico digestion of genomic DNA, step (2) evaluating the in silico frequency of fragment size distribution between individual chromosomes, step (3) selecting those enzymes that generate fragments with the majority between 100 bp and 3,000 bp, step (4) weighing the advantages and …


A Heuristic Ontological Model Of Protein Complexes A Case Study Based On The E3 Ubiquitin Ligase Protein Complexes Of Arabidopsis Thaliana, Claudia Dinatale Jan 2012

A Heuristic Ontological Model Of Protein Complexes A Case Study Based On The E3 Ubiquitin Ligase Protein Complexes Of Arabidopsis Thaliana, Claudia Dinatale

Electronic Theses and Dissertations

Ontology (with a capital O) is the philosophical study of the nature of existence that was derived to define the relationships of entities that can be said to exist in nature. The concept of an ontology was later adopted by the biological sciences to formally represent knowledge within a biological domain in order to standardize the annotation of biological data, and further, enable more efficient and easier data collection, sharing, and reuse across biological and model organism databases. The Protein Ontology (PRO) is a specific biological ontology developed to represent the relationships between proteins and protein complexes. This thesis presents …


Plastids And Pathogens: Mechanosensitive Channels And Survival In A Hypoosmotic World, Kira M. Veley, Elizabeth S. Haswell Jan 2012

Plastids And Pathogens: Mechanosensitive Channels And Survival In A Hypoosmotic World, Kira M. Veley, Elizabeth S. Haswell

Biology Faculty Publications & Presentations

In bacteria, MscS-type mechanosensitive channels serve to protect cells from lysis as they swell during extreme osmotic stress. We recently showed that two MscS homologs from Arabidopsis thaliana serve a similar purpose in the epidermal plastids of the leaf, indicating that the plant cell cytoplasm can present a dynamic osmotic challenge to the plastid. MscS homologs are predicted to be targeted to both plastids and mitochondrial envelopes and have been found in the genomes of intracellular pathogens. Here we discuss the implications of these observations, and propose that MS channels provide an essential mechanism for osmotic adaptation to both intracellular …


Functional Analysis Of Conserved Motifs In The Mechanosensitive Channel Homolog Mscs-Like2 From Arabidopsis Thaliana, Gregory S. Jensen, Elizabeth S. Haswell Jan 2012

Functional Analysis Of Conserved Motifs In The Mechanosensitive Channel Homolog Mscs-Like2 From Arabidopsis Thaliana, Gregory S. Jensen, Elizabeth S. Haswell

Biology Faculty Publications & Presentations

The Mechanosensitive channel of Small conductance (MscS) of Escherichia coli has become an excellent model system for the structural, biophysical, and functional study of mechanosensitive ion channels. MscS, a complex channel with multiple states, contributes to protection against lysis upon osmotic downshock. MscS homologs are widely and abundantly dispersed among the bacterial and plant lineages, but are not found in animals. Investigation into the eukaryotic branch of the MscS family is in the beginning stages, and it remains unclear how much MscS homologs from eukaryotes resemble E. coli MscS with respect to structure, function, and regulation. Here we test the …