One of the largest problems in current medicine is the shortage of organs for transplant due to technological limitations in the storage of organs for any length of time. A possible solution to this problem would involve cryopreservation. However, current cryopreservatives such as sucrose or DMSO have concerning cytotoxic issues that limit their possible applications. A major cause of cryoinjury is the uncontrolled recrystallization of inter and intra-cellular ice crystals that occurs during the thawing process leading to mechanical damage and dehydration. The Ben lab has thus been interested in the design of compounds that are capable of inhibiting this process but do not possess other undesirable properties found in the native compounds. These synthetic analogues have been shown to increase cellular viability post-thaw. A series of mixed α/β glycopeptides are prepared and analyzed for antifreeze properties. The results of this study imply that it is not the gross conformation of the glycopeptide that is responsible for activity, but rather that intramolecular relationships may be responsible for disrupting the reorganization of ice. A technique was devised for the incorporation of triazoles into the analogues to investigate the importance of the linker and to greatly simplify the synthesis of a library of glycoconjugates. It was found that the IRI activity of glycopeptides is very sensitive to the distance between carbohydrate and peptide backbone. The electron density at the anomeric oxygen is an important parameter with respect to intramolecular networks. A series of substituted galactosides is presented that modify the electronics of the anomeric oxygen. The results demonstrate that decreasing electron density at this position appears to improve IRI activity in a predictable manner. To better understand the remarkable IRI activity of a key analogue, it was systematically truncated. This study led to the serendipitous discovery of a series of very highly IRI active analogues that do not contain a peptide backbone. These compounds represent the first non-glycopeptides that can show very significant IRI activity even at very low concentrations. The final portion of the thesis reports the efforts towards the preparation of a carbasugar analogue of AFGP-8.

One of the largest problems in current medicine is the shortage of organs for transplant due to technological limitations in the storage of organs for any length of time. A possible solution to this problem would involve cryopreservation. However, current cryopreservatives such as sucrose or DMSO have concerning cytotoxic issues that limit their possible applications. A major cause of cryoinjury is the uncontrolled recrystallization of inter and intra-cellular ice crystals that occurs during the thawing process leading to mechanical damage and dehydration. The Ben lab has thus been interested in the design of compounds that are capable of inhibiting this process but do not possess other undesirable properties found in the native compounds. These synthetic analogues have been shown to increase cellular viability post-thaw. A series of mixed α/β glycopeptides are prepared and analyzed for antifreeze properties. The results of this study imply that it is not the gross conformation of the glycopeptide that is responsible for activity, but rather that intramolecular relationships may be responsible for disrupting the reorganization of ice. A technique was devised for the incorporation of triazoles into the analogues to investigate the importance of the linker and to greatly simplify the synthesis of a library of glycoconjugates. It was found that the IRI activity of glycopeptides is very sensitive to the distance between carbohydrate and peptide backbone. The electron density at the anomeric oxygen is an important parameter with respect to intramolecular networks. A series of substituted galactosides is presented that modify the electronics of the anomeric oxygen. The results demonstrate that decreasing electron density at this position appears to improve IRI activity in a predictable manner. To better understand the remarkable IRI activity of a key analogue, it was systematically truncated. This study led to the serendipitous discovery of a series of very highly IRI active analogues that do not contain a peptide backbone. These compounds represent the first non-glycopeptides that can show very significant IRI activity even at very low concentrations. The final portion of the thesis reports the efforts towards the preparation of a carbasugar analogue of AFGP-8.

A novel approach for the production of soy protein isolates was investigated integrating electroacidification and membrane ultrafiltration. The effect of electroacidification on the ultrafiltration performance and physicochemical properties of the soy protein extracts was obtained by comparing an electroacidified (pH 6) and a non-electroacidified (pH 9) soy protein extract. The effect of membrane fouling on the permeate flux decline was studied in a hollow fiber and a dead end ultrafiltration system. Due to more significant membrane fouling, the permeate flux was always lower for the electroacidified extract, resulting in at least 1.5-fold increase in the total fouling resistance compared to the non-electroacidified extract. The total amount of protein deposited on the membrane surface during unstirred dead-end ultrafiltration was comparable (about 7 mg/cm2) for both soy protein extracts. The discrepancy between the total fouling resistance and the protein deposition estimates was attributed to the formation of denser (less permeable) fouling deposit for the electroacidified extract, which was supported by scanning electron microscopy studies of fouled membranes. The removal of carbohydrates and minerals was evaluated for direct ultrafiltration and two-stage discontinuous diafiltration using a hollow fiber system. The carbohydrate removal results were always consistent with the theoretical predictions, indicating that the carbohydrates were freely permeable across the membrane. In contrast, the minerals were partially retained by the membrane, but to a higher extent for the non-electroacidified extract, which demonstrated that the electroacidification pretreatment enhanced the mineral removal during the ultrafiltration. Incorporation of the diafiltration step improved the ash (mineral) and carbohydrate removal. Stronger electrostatic interactions between soy proteins, calcium/magnesium, and phytic acid (antinutrient) at alkaline pH resulted in less efficient removal of calcium, magnesium, and phytic acid during the ultrafiltration of the non-electroacidified extract compared to the electroacidified extract. Consequently, the soy protein isolates produced by electroacidification and the hollow fiber ultrafiltration had a lower mineral and phytic acid content. The protein content was at least 88 % (dry basis), with or without the electroacidification pretreatment. The study of the viscosity revealed that the electroacidification pretreatment reduced the viscosity of the soy protein extract, which resulted in a lower axial pressure drop increase during the ultrafiltration of the electroacidified extract compared to the non-electroacidified extract. Adjusting the pH of the electroacidified extract to 9 and the pH of the non-electroacidified extract to 6 had a great impact on the particle size distribution but only a marginal effect on the viscosity of the pH adjusted extracts. This indicated that the pH and the particle size distribution were not responsible for the viscosity difference between the electroacidified and the non-electroacidified soy protein extracts. It was proposed that the electroacidification pretreatment had some impact on the water hydration capacity of the soy proteins, which consequently affected the viscosity.

Glycosylation, the addition of one or more carbohydrates molecules to a protein, is crucial for many cellular processes. Aberrant glycosylation is a key marker for various diseases such as cancer and rheumatoid arthritis. It has also recently been discovered that glycosylation is important in the ability of the Human Immunodeficiency Virus (HIV) to evade recognition by the immune system. Given the importance of glycosylation in disease, major efforts are underway in life science research to investigate the glycome, the entire glycosylation profile of an organelle, cell or tissue type. To date, little bioinformatics research has been performed in glycomics due to the complexity of glycan structures and the low throughput of carbohydrate analysis. Recent advances in mass spectrometry (MS) have greatly facilitated the analysis of the glycome. Increasingly, this technology is preferred over traditional methods of carbohydrate analysis which are often laborious and unsuitable for low abundance glycoproteins. When subject to mass spectrometry with collision-induced dissociation, glycopeptides produce characteristic MS/MS spectra that can be detected by visual inspection. However, given the high volume of data output from proteome studies today, manually searching for glycopeptides is an impractical task. In this thesis, we present a tool to automate the identification of glycopeptide spectra from MS/MS data. Further, we discuss some methodologies to automate the elucidation of the structure of the carbohydrate moiety of glycopeptides by adapting traditional MS/MS ion searching techniques employed in peptide sequence determination. MS/MS ion searching, a common technique in proteomics, aims to interpret MS/MS spectra by correlating structures from a database to the patterns represented in the spectrum. The tool was tested on high throughput proteomics data and was shown to identify 97% of all glycopeptides present in the test data. Further, the tool assigned correct carbohydrate structures to many of these glycopeptide MS/MS spectra. Applications of the tool in a proteomics environment for the analysis of glycopeptide expression in cancer tissue are also be presented.

A novel approach for the production of soy protein isolates was investigated integrating electroacidification and membrane ultrafiltration. The effect of electroacidification on the ultrafiltration performance and physicochemical properties of the soy protein extracts was obtained by comparing an electroacidified (pH 6) and a non-electroacidified (pH 9) soy protein extract. The effect of membrane fouling on the permeate flux decline was studied in a hollow fiber and a dead end ultrafiltration system. Due to more significant membrane fouling, the permeate flux was always lower for the electroacidified extract, resulting in at least 1.5-fold increase in the total fouling resistance compared to the non-electroacidified extract. The total amount of protein deposited on the membrane surface during unstirred dead-end ultrafiltration was comparable (about 7 mg/cm2) for both soy protein extracts. The discrepancy between the total fouling resistance and the protein deposition estimates was attributed to the formation of denser (less permeable) fouling deposit for the electroacidified extract, which was supported by scanning electron microscopy studies of fouled membranes. The removal of carbohydrates and minerals was evaluated for direct ultrafiltration and two-stage discontinuous diafiltration using a hollow fiber system. The carbohydrate removal results were always consistent with the theoretical predictions, indicating that the carbohydrates were freely permeable across the membrane. In contrast, the minerals were partially retained by the membrane, but to a higher extent for the non-electroacidified extract, which demonstrated that the electroacidification pretreatment enhanced the mineral removal during the ultrafiltration. Incorporation of the diafiltration step improved the ash (mineral) and carbohydrate removal. Stronger electrostatic interactions between soy proteins, calcium/magnesium, and phytic acid (antinutrient) at alkaline pH resulted in less efficient removal of calcium, magnesium, and phytic acid during the ultrafiltration of the non-electroacidified extract compared to the electroacidified extract. Consequently, the soy protein isolates produced by electroacidification and the hollow fiber ultrafiltration had a lower mineral and phytic acid content. The protein content was at least 88 % (dry basis), with or without the electroacidification pretreatment. The study of the viscosity revealed that the electroacidification pretreatment reduced the viscosity of the soy protein extract, which resulted in a lower axial pressure drop increase during the ultrafiltration of the electroacidified extract compared to the non-electroacidified extract. Adjusting the pH of the electroacidified extract to 9 and the pH of the non-electroacidified extract to 6 had a great impact on the particle size distribution but only a marginal effect on the viscosity of the pH adjusted extracts. This indicated that the pH and the particle size distribution were not responsible for the viscosity difference between the electroacidified and the non-electroacidified soy protein extracts. It was proposed that the electroacidification pretreatment had some impact on the water hydration capacity of the soy proteins, which consequently affected the viscosity.

No description available.

No description available.

No description available.

Diorhabda elongata elongata leaf beetles were released at two field locations in the upper Colorado River watershed of Texas in 2003 and 2004 for the biological control of invasive Tamarix, exotic trees deteriorating riparian ecosystems of western North America. Establishment and biological success were monitored using trees on transects from the release points. D. elongata elongata released at the Lake Thomas site in August 2003 successfully overwintered and were recovered in the spring 2004; however, beetles were not present after June 2004. The April 2004 release at Beals Creek led to establishment and survival during 2005 and 2006. Mean abundance increased from less than five insects per tree per 2 minute count in August 2004 to more than 40 insects per tree per 2 minute count in August 2006. By then the population was dispersed throughout an area of approximately 12 hectares and beetles were present on 100% of the 47 trees surveyed, 57% of which were at least 90% defoliated. To measure the impact of beetle defoliation on Tamarix, nonstructural carbohydrates (NCHOs) were measured in manipulative field cage experiments in Texas and natural experiments in Nevada. There was no significant difference in NCHOs between trees with versus trees without beetle herbivory in the cage experiment, although spring foliage regrowth was reduced by 35% in trees defoliated the previous fall. In Nevada, root crown tissue was sampled in 2005 and 2006 from trees that had experienced 0-4 years of defoliation. In 2005, NCHO concentrations differed between tree stands and ranged from 9.0 ± 0.8% (Mean ± SE) in non-defoliated trees to 3.2 ± 0.4%, 2.1 ± 0.4% and 2.3 ± 0.4% in trees defoliated for 1, 2 and 3 successive years, respectively. NCHO concentrations in 2006 were similar, ranging from 13.6 ± 0.9% in non-defoliated trees to 7.6 ± 0.8%, 2.3 ± 0.4%, 1.5 ± 0.3% and 1.7 ± 0.4% in trees defoliated for 1, 2, 3 and 4 years, respectively. The establishment, biological success and host impact of D. elongata leaf beetles suggest there is potential for biological control of Tamarix in the United States.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1964. / Bibliography: leaves 90-93.