Thesis (M.Eng.). / Written for the Dept. of Chemical Engineering. Title from title page of PDF (viewed 2008/01/14). Includes bibliographical references.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2004. / Includes bibliographical references.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 62-68.

A major problem associated with cellular cryopreservation is the recovery of cellular viability upon thawing. Current cryopreservation techniques use additives such as DMSO, sucrose and fetal bovine serum. However, each have their own respective cytotoxic issues. A significant factor in cryotoxicity is the formation of large ice crystals which can damage cellular components and cause dehydration. This has significant impacts for applications such as food preservation, scientific research, and tissue preservation. To this end, our laboratory is interested in synthesizing biologically-relevant compounds that can act as cryoprotectants by preventing the formation of large ice crystals in sub-zero temperatures. Our lab has previously synthesized structural analogues of native antifreeze glycoproteins (AFGPs, found in the blood of Antarctic cod), that possess the unique ability to inhibit ice-recrystallization. However, the mechanism by which they inhibit ice recrystallization is unclear. This thesis focuses on efforts made to understand this mechanism, and synthesize molecules that are more potent in ice recrystallization inhibition (IRI) activity compared to previously synthesized analogues. By assessing the IRI activity of various mono- and disaccharides, we have shown that the density of water molecules that surround a carbohydrate (Hydration Index) is directly proportional to the ability of sugars to inhibit ice crystal growth. In an effort to design functional AFGP analogues, various C-linked analogues were synthesized that contained different spacer lengths between the carbohydrate and the peptide backbone. Analyses of the solution conformations of these analogues showed that IRI-active AFGP analogues contain a distinct conformation in which the carbohydrate is oriented to form a hydrophobic pocket with the side chain. We hypothesize that this change in glycoconjugate hydration is responsible for disturbing its surrounding waters, thereby preventing water from adding to the ice lattice required for ice growth. Finally, SAR studies showed that threonine-containing AFGP and antifreeze proteins are more potent in antifreeze activity than serine-containing analogues. As the most potent AFGP analogue previously synthesized by our lab contains a C-linked-α-galactosyl -serine residue, we hypothesized that the analogous glycopeptide containing a C-α-galactosyl-threonine residue will be more potent in antifreeze activity. The final section describes efforts to synthesize a C-linked α-galactosyl-threonine glycoconjugate.

A major problem associated with cellular cryopreservation is the recovery of cellular viability upon thawing. Current cryopreservation techniques use additives such as DMSO, sucrose and fetal bovine serum. However, each have their own respective cytotoxic issues. A significant factor in cryotoxicity is the formation of large ice crystals which can damage cellular components and cause dehydration. This has significant impacts for applications such as food preservation, scientific research, and tissue preservation. To this end, our laboratory is interested in synthesizing biologically-relevant compounds that can act as cryoprotectants by preventing the formation of large ice crystals in sub-zero temperatures. Our lab has previously synthesized structural analogues of native antifreeze glycoproteins (AFGPs, found in the blood of Antarctic cod), that possess the unique ability to inhibit ice-recrystallization. However, the mechanism by which they inhibit ice recrystallization is unclear. This thesis focuses on efforts made to understand this mechanism, and synthesize molecules that are more potent in ice recrystallization inhibition (IRI) activity compared to previously synthesized analogues. By assessing the IRI activity of various mono- and disaccharides, we have shown that the density of water molecules that surround a carbohydrate (Hydration Index) is directly proportional to the ability of sugars to inhibit ice crystal growth. In an effort to design functional AFGP analogues, various C-linked analogues were synthesized that contained different spacer lengths between the carbohydrate and the peptide backbone. Analyses of the solution conformations of these analogues showed that IRI-active AFGP analogues contain a distinct conformation in which the carbohydrate is oriented to form a hydrophobic pocket with the side chain. We hypothesize that this change in glycoconjugate hydration is responsible for disturbing its surrounding waters, thereby preventing water from adding to the ice lattice required for ice growth. Finally, SAR studies showed that threonine-containing AFGP and antifreeze proteins are more potent in antifreeze activity than serine-containing analogues. As the most potent AFGP analogue previously synthesized by our lab contains a C-linked-α-galactosyl -serine residue, we hypothesized that the analogous glycopeptide containing a C-α-galactosyl-threonine residue will be more potent in antifreeze activity. The final section describes efforts to synthesize a C-linked α-galactosyl-threonine glycoconjugate.

A major problem associated with cellular cryopreservation is the recovery of cellular viability upon thawing. Current cryopreservation techniques use additives such as DMSO, sucrose and fetal bovine serum. However, each have their own respective cytotoxic issues. A significant factor in cryotoxicity is the formation of large ice crystals which can damage cellular components and cause dehydration. This has significant impacts for applications such as food preservation, scientific research, and tissue preservation. To this end, our laboratory is interested in synthesizing biologically-relevant compounds that can act as cryoprotectants by preventing the formation of large ice crystals in sub-zero temperatures. Our lab has previously synthesized structural analogues of native antifreeze glycoproteins (AFGPs, found in the blood of Antarctic cod), that possess the unique ability to inhibit ice-recrystallization. However, the mechanism by which they inhibit ice recrystallization is unclear. This thesis focuses on efforts made to understand this mechanism, and synthesize molecules that are more potent in ice recrystallization inhibition (IRI) activity compared to previously synthesized analogues. By assessing the IRI activity of various mono- and disaccharides, we have shown that the density of water molecules that surround a carbohydrate (Hydration Index) is directly proportional to the ability of sugars to inhibit ice crystal growth. In an effort to design functional AFGP analogues, various C-linked analogues were synthesized that contained different spacer lengths between the carbohydrate and the peptide backbone. Analyses of the solution conformations of these analogues showed that IRI-active AFGP analogues contain a distinct conformation in which the carbohydrate is oriented to form a hydrophobic pocket with the side chain. We hypothesize that this change in glycoconjugate hydration is responsible for disturbing its surrounding waters, thereby preventing water from adding to the ice lattice required for ice growth. Finally, SAR studies showed that threonine-containing AFGP and antifreeze proteins are more potent in antifreeze activity than serine-containing analogues. As the most potent AFGP analogue previously synthesized by our lab contains a C-linked-α-galactosyl -serine residue, we hypothesized that the analogous glycopeptide containing a C-α-galactosyl-threonine residue will be more potent in antifreeze activity. The final section describes efforts to synthesize a C-linked α-galactosyl-threonine glycoconjugate.

Thesis (Ph. D.)--State University of New York at Binghamton, Chemistry Department, 2004. / Includes bibliographical references.

A major problem associated with cellular cryopreservation is the recovery of cellular viability upon thawing. Current cryopreservation techniques use additives such as DMSO, sucrose and fetal bovine serum. However, each have their own respective cytotoxic issues. A significant factor in cryotoxicity is the formation of large ice crystals which can damage cellular components and cause dehydration. This has significant impacts for applications such as food preservation, scientific research, and tissue preservation. To this end, our laboratory is interested in synthesizing biologically-relevant compounds that can act as cryoprotectants by preventing the formation of large ice crystals in sub-zero temperatures. Our lab has previously synthesized structural analogues of native antifreeze glycoproteins (AFGPs, found in the blood of Antarctic cod), that possess the unique ability to inhibit ice-recrystallization. However, the mechanism by which they inhibit ice recrystallization is unclear. This thesis focuses on efforts made to understand this mechanism, and synthesize molecules that are more potent in ice recrystallization inhibition (IRI) activity compared to previously synthesized analogues. By assessing the IRI activity of various mono- and disaccharides, we have shown that the density of water molecules that surround a carbohydrate (Hydration Index) is directly proportional to the ability of sugars to inhibit ice crystal growth. In an effort to design functional AFGP analogues, various C-linked analogues were synthesized that contained different spacer lengths between the carbohydrate and the peptide backbone. Analyses of the solution conformations of these analogues showed that IRI-active AFGP analogues contain a distinct conformation in which the carbohydrate is oriented to form a hydrophobic pocket with the side chain. We hypothesize that this change in glycoconjugate hydration is responsible for disturbing its surrounding waters, thereby preventing water from adding to the ice lattice required for ice growth. Finally, SAR studies showed that threonine-containing AFGP and antifreeze proteins are more potent in antifreeze activity than serine-containing analogues. As the most potent AFGP analogue previously synthesized by our lab contains a C-linked-α-galactosyl -serine residue, we hypothesized that the analogous glycopeptide containing a C-α-galactosyl-threonine residue will be more potent in antifreeze activity. The final section describes efforts to synthesize a C-linked α-galactosyl-threonine glycoconjugate.

Interpretation of crystallographic and mutational studies of antifreeze proteins (AFPs) requires molecular modeling of AFPs with ice. Most models proposed so far suggested H-bonds as the major driving force of AFP-ice association. However, the bulk water offers optimal network of H-bonds and van der Waals contacts to the isolated AFP and ice suggesting that corresponding components of free energy would not decrease upon AFP-ice association. In an attempt to resolve this controversy, we Monte Carlominimized complexes of several AFPs with taking into account, in addition to nonbonded interactions and H-bonds, the hydration potential for proteins (Augspurger and Scheraga, 1996). Parameters of the hydration potential for ice were developed basing on an assumption that at the melting temperature the free energy of water-ice association is small. Simulations demonstrate that desolvation of hydrophobic groups in the AFPs upon their fitting to the grooves at the ice surface presents the major stabilizing contributions to the free energy of AFP-ice binding. Our results explain available data on structure of AFPs and their mutational analyses, in particular, a paradoxical fact that substitution of Thr residues to Val does not affect potency of Winter Flounder AFP. / Thesis / Master of Science (MS)

This investigation was based upon the work of Lenth and DuPuis and Stengel and Maple, who hydrogenated sugar suspended in methanol at 240°C and 1500 lbs. per sq. in. for three hours with the primary purpose of developing a new process. to produce glycerine to make up for the shortage created in World War II. The products of the hydrogenation were water, propylene glycol, glycerol and congeners, and a residue made up of the tarry decomposition products of sugar. The actual glycerol and congeners fraction obtained by Lenth and DuPuis was secured from the Miner Laboratories in Chicago. This impure glycerine fraction and propylene glycol were mixed together, and its suitability as an automotive antifreeze was tested. AB far as viscosity and freezing point depression were concerned, such an automotive antifreeze compares favorably with ethylene glycol. The economics of the process were studied, and a tentative plant was designed to produce 3000 tons per year which would require a capital investment of about $529,775 and have a wholesale price of $0.217 per lb. with sugar costing $0.04. This coat may be reduced by catalyst recovery and a reduction in sugar cost. / M.S.