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Full-Text Articles in Engineering

Computational Methods In The Study Of Carbohydrates And Carbohydrate-Active Enzymes , Anthony David Hill Jan 2006

Computational Methods In The Study Of Carbohydrates And Carbohydrate-Active Enzymes , Anthony David Hill

Retrospective Theses and Dissertations

Carbohydrates are important molecules in energy storage and cellular recognition. New methods are used and discussed to capture important structural details of created by the protein/carbohydrate interactions. In particular, the thermodynamics of carbohydrate binding are explored, and a new model to accurately calculate the free energy of binding is developed. Additionally, a new method of describing the pucker of carbohydrate ring with three coordinates is discussed. These methods are then applied to Family 1 Glycoside Hydrolases.


Carbon-13 Metabolic Flux Analysis Of Soybean Central Carbon Metabolism: Response To Temperature And Genotype Effects , Vidya Vaancheeswaran Iyer Jan 2006

Carbon-13 Metabolic Flux Analysis Of Soybean Central Carbon Metabolism: Response To Temperature And Genotype Effects , Vidya Vaancheeswaran Iyer

Retrospective Theses and Dissertations

Soybeans are a major source of high quality protein, edible oil, food products, and also several industrial non food applications such as paper coating, textiles and plastics. It is difficult to develop soybeans with high protein and high oil, however, due to the inverse relationship between these two components. Consequently, increasing seed protein concentration without adversely affecting the yield and oil content has been difficult to achieve. It has been demonstrated that the temperature and genotype of soybeans influence the protein or lipid composition considerably. However, the interactions between various pathways responsible for the changes in the composition are unknown ...


Directed Growth And Selective Differentiation Of Neural Progenitor Cells Using A Synergistic Combination Of Topographical And Soluble Cues , Jennifer Behr Recknor Jan 2006

Directed Growth And Selective Differentiation Of Neural Progenitor Cells Using A Synergistic Combination Of Topographical And Soluble Cues , Jennifer Behr Recknor

Retrospective Theses and Dissertations

The purpose of this study is to develop strategies to facilitate nerve regeneration using a synergistic combination of guidance cues. We are investigating the cellular mechanisms of development using adult rat hippocampal progenitor cells (AHPCs) and have demonstrated that manipulating a combination of physical, chemical and biological cues can lead to oriented astrocyte and neural progenitor cell outgrowth and can influence progenitor cell differentiation. To provide physical guidance, micropatterned polystyrene (PS) substrates were fabricated and chemically modified with laminin. Astrocytes or AHPCs cultured on these substrates align along the grooves of the patterned surface extending highly elongated processes. To further ...


Flux Analysis In Central Carbon Metabolism In Plants: 13c Nmr Experiments And Analysis , Ganesh Sriram Jan 2004

Flux Analysis In Central Carbon Metabolism In Plants: 13c Nmr Experiments And Analysis , Ganesh Sriram

Retrospective Theses and Dissertations

Metabolic flux analysis is crucial in metabolic engineering. This research concentrated on improvements in 13C labeling-based flux analysis, a powerful flux quantification method, particularly oriented toward application to plants. Furthermore, systemic 13C flux analyses were performed on two model plant systems: Glycine max (soybean) embryos, and Catharanthus roseus hairy roots.;The concepts 'bond integrity', 'bondomer' and the algorithm 'Boolean function mapping' were introduced, to facilitate efficient flux evaluation from carbon bond labeling experiments, and easier flux identifiability analysis.;13C labeling experiments were performed on developing soybean (Glycine max) embryos and C. roseus hairy roots. A computer program, NMR2Flux, was developed ...


Tnt Phytotransformation In Native And Genetically Modified Species: Significance Of Aromatic Hydroxylamines In The Metabolic Pathway , Murali Subramanian Jan 2004

Tnt Phytotransformation In Native And Genetically Modified Species: Significance Of Aromatic Hydroxylamines In The Metabolic Pathway , Murali Subramanian

Retrospective Theses and Dissertations

The presence and role of hydroxylamines in TNT transformation were ascertained in two axenic (microbe-free) hydroponic plant systems through high TNT feeding experiments and the use of different analytical detection schemes. Hydroxylamines were formed within 10 hours of TNT addition, and usually disappeared within 20 hours, displaying a high turnover rate due to their instability and high reactivity. Hydroxylamines were shown to add biomolecules to their functional group and thereby directly form conjugates. The 4-isomer of the hydroxylamine was detected in very high levels (up to 30% of initial TNT added) in a transgenic tobacco system that had a bacterial ...


Recovery Of Recombinant Proteins From Transgenic Plants: Strategies In Implementation And Optimization , Todd J. Menkhaus Jan 2002

Recovery Of Recombinant Proteins From Transgenic Plants: Strategies In Implementation And Optimization , Todd J. Menkhaus

Retrospective Theses and Dissertations

Strategies to optimize the recovery of recombinant proteins from plant hosts have been investigated. The use of different crops, different product molecules, and different separation techniques was studied to suggest modes of operation that reduce the overall processing cost for obtaining purified recombinant proteins from plants.;Polyelectrolyte precipitation of beta-glucuronidase (GUS), an acidic model protein, with polyethyleneimine (PEI), a polycatonic polymer, from the extracts of canola, corn germ, soybean, and pea met with varying degrees of success. Precipitation from canola required the least amount of PEI and was capable of providing the highest enrichment. In contrast, soy and pea allowed ...


Design Of A Bioartificial Nerve Graft , Gregory Edward Rutkowski Jan 1999

Design Of A Bioartificial Nerve Graft , Gregory Edward Rutkowski

Retrospective Theses and Dissertations

Nerve injuries complicate successful rehabilitation more than any other form of trauma because of loss of protective sensibility and tactile discrimination, denervation atrophy of muscles, and pain syndromes. While achieving full function and organ reinnervation after peripheral nerve injury is a challenge, a promising method of improving the rate and success of regeneration is the bioartificial nerve graft (BNG). The BNG developed in the laboratory consists of a porous bioresorbable tube containing cultured Schwann cells that help to direct and support nerve regeneration when used to bridge the gap between the ends of the severed nerve;To aid in the ...


Development Of An Empirical Model Of Human Sweating And A Semi-Empirical Model Of Human Thermoregulation , Jennifer Jane Walker Jan 1999

Development Of An Empirical Model Of Human Sweating And A Semi-Empirical Model Of Human Thermoregulation , Jennifer Jane Walker

Retrospective Theses and Dissertations

The physiology of the human thermoregulatory response to changes in environment and work load has been studied from the perspective of both the physiologist and the engineer. Both fields have brought certain skills and tools to the effort. An effort to bring together the understanding gained from these two perspectives has been lacking. In this work a model for the sweat response and a model for the thermoregulatory response to changes in room temperature were developed. These models were developed using the modeling tools of engineering and the knowledge contained in past experimental data;An empirical model of the sweat ...


Enhancing Chromatographic Separations Of Recombinant Proteins From Canola Extracts By Genetic Design And Characterization Of Protein Binding Regions , Chenming Zhang Jan 1999

Enhancing Chromatographic Separations Of Recombinant Proteins From Canola Extracts By Genetic Design And Characterization Of Protein Binding Regions , Chenming Zhang

Retrospective Theses and Dissertations

Canola was studied as an alternative source to traditional microbial systems as a recombinant protein production host. Various chromatographic methods were used in this work to systematically characterize the native canola protein elution profiles, and different genetically engineered proteins were selected to explore the opportunities presented for effective protein recovery;Native canola protein was eluted into two major peaks in linear salt gradient elution on cation-exchange chromatography. T4 lysozyme and its mutants, by both point mutation and fusion, were used as model proteins to investigate the charge effect on protein elution. It was found that the single mutant T4 lysozyme ...


The Effects Of Physiological Levels Of Intermittent Pressure On The Development Of Articular Cartilage In Vitro , Scott Edward Carver Jan 1998

The Effects Of Physiological Levels Of Intermittent Pressure On The Development Of Articular Cartilage In Vitro , Scott Edward Carver

Retrospective Theses and Dissertations

A semi-continuous perfusion system has been designed and constructed to deliver physiological levels of hydrostatic pressure to regenerating cell/polymer constructs of articular cartilage over the long term (weeks to months). Prior to being transferred to the pressurized system, equine articular chondrocytes were dynamically seeded onto nonwoven meshes of polyglycolic acid which provide the cells with a three-dimensional growth environment similar to that found in vivo. When applied in an intermittent manner, physiological pressurization at 500 psi was found to stimulate articular chondrocytes to produce regenerated constructs with greater concentrations of sulfated glycosaminoglycan compared to control (unpressurized) constructs, while the ...


Development Of A Coupled Model Of The Cardiorespiratory And Thermoregulatory Systems , Dawn Denise Downey Jan 1998

Development Of A Coupled Model Of The Cardiorespiratory And Thermoregulatory Systems , Dawn Denise Downey

Retrospective Theses and Dissertations

A model of the human body which integrates the variables involved in temperature regulation and blood gas transport within the cardiovascular and respiratory systems is presented in this dissertation. It expands upon previous work developed by the author to model the competition between skin and muscles when both require increased blood flows during exercise and/or heat stress. First, a detailed study of the control relations used to predict skin blood flow was undertaken. Four other control relations employed in the model were also examined and modified as indicated by empirical results found in literature;Several important cases were then ...


A Quantitative Estimation Of Regulation And Transport Limitations In The Human Cardiopulmonary System , Sharmista Chatterjee Jan 1997

A Quantitative Estimation Of Regulation And Transport Limitations In The Human Cardiopulmonary System , Sharmista Chatterjee

Retrospective Theses and Dissertations

The object of this dissertation is to quantitatively describe the regulation of some of the exchange processes within the human body. Conceptually this dissertation is divided into two sections. In the first section a macroscopic view was adopted to describe the overall regulation of the cardiovascular and respiratory systems. These overall system models were used as heuristic tools to gain an understanding of physiological behavior in micro-gravity. In the second section, a microscopic view was used to estimate the role played by the surfactant system of the lung in regulating the transfer of fluid across the pulmonary-capillary wall;The basis ...


Computational Studies Of Glucoamylase Selectivity , Pedro Maldonado Coutinho Jan 1996

Computational Studies Of Glucoamylase Selectivity , Pedro Maldonado Coutinho

Retrospective Theses and Dissertations

Glucoamylase (GA) is an industrial enzyme involved in the production of glucose and fructose syrups from starch. Exhibiting a large spectrum of selectivities, GAs are able to cleave glucose from the nonreducing ends of [alpha]-(1,4) glycosidic bonds of maltooligosaccharide chains and the [alpha]-(1,6) bonds initiating their branches. The high temperatures and glucose concentrations occurring in saccharification lead to the formation of condensation products, reducing the overall glucose yield. Modified versions of Aspergillus GA that better satisfy industrial requirements are desirable. To achieve this, a structure-based multisequence alignment of the primary sequences of the catalytic domains, linkers ...


Water Reuse In Fermentations , Tzu-Yin Hsiao Jan 1995

Water Reuse In Fermentations , Tzu-Yin Hsiao

Retrospective Theses and Dissertations

This work was undertaken to investigate the feasibility of reusing the process effluent from fermentation processes to minimize the liquid waste. Two fermentations with different characteristics were chosen as model fermentations for development of principles. The first was a yeast fermentation that requires high levels of carbon substrate for production of intracellular lipid. The second was a bacterial fermentation requiring high levels of nitrogen in the medium for production of lysine. The latter is used for commercial production of lysine;In the study of the first model fermentation, Apiotrichum curvatum, an oleaginous yeast, was used as the working culture. Spent ...


Enhancement Of Polyelectrolyte Precipitation Through The Genetic Fusion Of Charged Polypeptides To Enzymes , Mark Quinn Niederauer Jan 1993

Enhancement Of Polyelectrolyte Precipitation Through The Genetic Fusion Of Charged Polypeptides To Enzymes , Mark Quinn Niederauer

Retrospective Theses and Dissertations

The focus of this work was to investigate the enhancement of polyelectrolyte precipitation through the genetic alteration of the target protein. The dissertation is divided into three primary chapters: a literature review of precipitation techniques which display high selectivity, experimental work including the characterization and precipitation of the fusion enzymes, and modeling of the precipitation process;The literature review of selective precipitation techniques focuses on those techniques for which relatively high purifications can be achieved. The techniques include precipitation with polyelectrolytes, affinity ligands, metal ions, and protein-binding dyes. Topics discussed include the mechanisms of selectivity and precipitation, degrees of purification ...


Charged Fusions For Enhanced Protein Purification And Immobilization By Ion-Exchange , Meng Hong Heng Jan 1993

Charged Fusions For Enhanced Protein Purification And Immobilization By Ion-Exchange , Meng Hong Heng

Retrospective Theses and Dissertations

This work was undertaken to investigate the enhanced binding of genetically engineered [beta]-galactosidase fusions in ion-exchange. The fusions used had a series of polyaspartate tails of the form: Gly-Asp-Pro-Met-Ala-(Asp)[subscript] n-Tyr fused to the carboxyl termini of the wild type [beta]-galactosidase (BGWT). The resulting fusions carried additional 1, 5, 11, and 16 negative charges and are designated as BGCD1, BGCD5, BGCD11, and BGCD16, respectively;The use of charged fusions for selective protein recovery was studied using hollow fiber ion-exchange membranes. The added tails allowed selective binding and release of [beta]-galactosidase in active form from Escherichia coli ...


Characterization Of Substrate Binding And Catalytic Mechanisms Of An Endoxylanase, Amylosucrase, And Porcine Pancreatic Alpha-Amylase , Bernard Yi Tao Jan 1988

Characterization Of Substrate Binding And Catalytic Mechanisms Of An Endoxylanase, Amylosucrase, And Porcine Pancreatic Alpha-Amylase , Bernard Yi Tao

Retrospective Theses and Dissertations

The subsite affinity map of an endo-(1 → 4)-[beta]-xylanase produced by Aspergillus niger has been determined by using linear, [superscript]3H-reducing-end-labeled xylooligosaccharides ranging in length from xylotriose through xylooctaose. No evidence of multiple attack or of condensation and transxylosylation reactions was found. Bond cleavage frequencies were highest near the reducing end of short substrates, with the locus of highest frequencies moving towards the middle of larger substrates. This endoxylanase has five major subsites, with the catalytic site located between the third and fourth subsites, counting from the non-reducing end of the bound substrate. The subsite to the non-reducing ...


Mutagenesis Of The Active Site Of Glucoamylase From Aspergillus Awamori , Michael R. Sierks Jan 1988

Mutagenesis Of The Active Site Of Glucoamylase From Aspergillus Awamori , Michael R. Sierks

Retrospective Theses and Dissertations

The Aspergillus awamori glucoamylase gene was modified by cassette mutagenesis, and eleven mutated enzymes were expressed by Saccharomyces cerevisiae;Four mutations were constructed to change the essential Trp 120 residue in subsite 4 to Tyr, Phe, His, and Leu. All the mutations bound maltose (G2) and isomaltose (iG2) more strongly than wild-type glucoamylase. A subsite map of the Tyr 120 mutation showed significantly higher affinities for D-glucosyl residues in subsites 1 and 2, suggesting an interaction of Trp 120 with residues located there;Three carboxylic acid residues in the active site, Asp 176, Glu 179, and Glu 180, were mutated ...