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In order to develop a radioimmunoassay for rat C-peptide, rat insulinoma, which contains large quantities of insulin and was expected also to contain large quantities of C-peptide, was chosen as a starting material. However, the tissue was found not to contain extractable C-peptide. Instead, a novel peptide (rat insulinoma peptide, RIP) was isolated. Rat insulinoma peptide (RIP) which appears to be either a fragment of, or an altered rat C-peptide was isolated and purified by dialysis. The purity of this peptide was investigated using polyacrylamide gel electrophoresis with sodium dodecyl sulphate, isoelectric focussing, and high performance liquid chromatography. RIP may contain two peptides similar to each other but differing in their isoelectric points. The molecular weight of RIP was found to be 1,982 daltons by fast atom bombardment mass spectrometry giving a chain length of approximately 22 amino acid residues. From information obtained using radioimmunoaasay employing antiserum R901, RIP appears to share a common C-terminus with rat C-peptide. A radioimmunoassay for RIP was developed using the purified RIP as immunogen and for standards and tracers. An indirect enzyme linked immunosorbent assay (ELISA) for rat insulinoma peptide was developed using purified RIP for immunogen and semi-purified RIP as a standard. Rat C-peptide I and II were successfully synthesised using the technique of solid phase peptide synthesis. The crude synthetic peptides were purified by dialysis, and their purity was assessed by high performance liquid chromatography. The molecular weight of these synthetic peptides was determined by fast atom bombardment mass spectrometry to be 3,183 daltons. These two synthetic peptides can be detected by rat C-peptide I radioimmunoassay employing antiserum R901. A radioimmunoassay for rat C-peptide I was developed using synthetic rat C-peptide I for immunogen, standard and tracer. The rat C-peptide I and II antisera were shown to produce positive staining of the islets of Langerhans of normal rat pancreas.

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No description available.

Antimicrobial (cationic) proteins play an important role in innate imunity. Such proteins can possess antibacterial, antiendotoxic or fungicidal abilities. The rising resistence of microbes to common antibiotics evokes acute need of studying more endogenous proteins to reveal new potential antibiotics. Ticks, the blood-feeding ectoparasites with effectual defense system, present an endless source of newly described and unknown antimicrobial peptides/proteins with significant theurapeutic potential. This study represents identification of histidine-rich proteins detected in Ixodes ricinus and Ixodes scapularis, that are related to recently described new family of proteins isolated from Rhipicephalus microplus (protein microplusin) and Amblyomma hebraeum (protein heraein). Analysis and characterization of newly identified histidine rich proteins, study of their antimicrobial and protease inhibitory effect are the main goals of this study.

Graduate

Master of Science / Biochemistry and Molecular Biophysics Interdepartmental Program / John M. Tomich / Nanocapsules have become more popular as potential therapeutic agents in recent years. Though liposomes are the most popular and well-studied, nanocapsules made of peptides have their distinct advantages as the research behind them intensifies. Branched Amphiphilic Peptide Capsules (BAPCs) are a type of self-assembling nanocapsules that are made up of two similar branched, amphiphilic, chemically synthesized peptides. These peptides self-assemble into bilayer delimited capsules capable of encapsulating solutes and even small proteins in aqueous solution. Previous studies have shown that these nanocapsules are taken up by cells in culture without negative effects and can be given to an organism, distributed throughout the organism without cytotoxic effects, suggesting a possible future as a therapeutic nanoparticle. For use as a therapeutic system, the understanding of how these BAPCs behave in the presence of sodium and chloride, two very common biological ions, must be understood and characterized. Previously published work showed that the BAPC bilayer is semipermeable and excludes sodium and chloride ions. Current research has expanded on this. Besides being semipermeable, this bilayer is also a dynamic membrane that has the ability to expand and contract due to osmotic pressure from ions in solution. Eosin Y, an autoquenching dye, has been used for many of the studies to monitor the behavior and the amount of water within the BAPCs. Having insight into how the BAPCs change under physiological conditions is necessary if these nanoparticles are to be used in a clinical setting and may open doors to new uses.

SMAC (Secondary Mitochondria-derived Activator of Caspases) mimetics have generated significant interest as potential chemotherapeutic compounds via their ability to promote apoptosis in cancer cells. These molecules target several Inhibitor of Apoptosis Proteins (IAPs) whose elevated expression is ubiquitous with tumorigenesis. We report several novel SMAC based peptidomimetics which appear to mirror the anti-IAP activity of SMAC in vitro. Elements of reported SMAC mimetics were combined with unique structural features to design novel, efficacious IAP antagonists. Our approach included modifications to the 2nd and 4th residues of the AVPI peptide sequence, the motif responsible for SMAC 's interaction with IAPs. Cell-based compound testing against MDA-MB-231 breast cancer cells identified several promising leads possessing nanomolar cytotoxic effects. Apoptotic activity was confirmed via capsase-3/7 activation, a hallmark of regulated cell death. Our experimental data suggests we have developed selective, potent anti-cancer compounds to be further developed in the pursuit of new anti-cancer therapeutics.