Cationic Polymers based on Fructose and Galactose Moieties for Nucleic Acids Delivery

Cationic polymers and glycopolymers were synthesised using the RAFT technique. Combining cationic polymers with glycopolymers has great potential in targeted nucleic acid delivery.1,2 However, many obstacles prevent the use of cationic glycopolymers as vectors including low success in nucleic acid delivery and high toxicity of the cationic polymer. This project aims to investigate RAFT synthesis of cationic glycopolymers with galactose or fructose carbohydrates, their binding ability with their specific lectins and with negatively charged nucleic acids. The cationic polymer poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) was synthesised using RAFT polymerisation. The galactose monomer, 2-(2’,3’,4’,6’-tetra-O-acetyl-β-D-galactosyloxy)ethyl methacrylate (AcGalEMA), and the fructose monomer, 1-O-methacryloyl-2,3:4,5-di-O-isopropylidene--D-fructopyranose (1-O-MAiPFru)3, were polymerised with PDMAEMA to form cationic glycopolymers. Chain extension was confirmed using proton nuclear magnetic spectroscopy (NMR) and gel permeation chromatography (GPC). Gel permeation chromatography was also performed to determine the polydispersity index (uniformity) of the polymers. The protected glycopolymer blocks were modified by deacetylation of the galactose block and acid deprotection of the fructose block. Characterisation of the modified cationic glycopolymers was achieved using proton nuclear magnetic spectroscopy for confirmation of deacetylation/deprotection, and dynamic light scattering to determine the sizes of the diblock copolymers. The zeta potential (ionic charge) of the diblock copolymers was recorded. Aggregation assays between the cationic glycopolymers and plant lectins were assessed. The galactose-containing glycopolymers were conjugated with peanut agglutinin lectin and the fructose-containing glycopolymers were conjugated with lectin from Ulex europaeus. The assays were analysed using dynamic light spectroscopy and ultraviolet-visible spectroscopy. Complexation of the cationic glycopolymer with small interfering RNA (siRNA) was accomplished. The size of the resulting polyplex was recorded with dynamic light spectroscopy. The zeta potential was measured and compared to the zeta potential measurement before complexation with siRNA. Results indicated that RAFT polymerisation was successful in producing diblock polymers of controlled weight and uniform size. The cationic glycopolymers were partially successful in deacetylation/deprotection and highly successful in binding to their specific lectins. The cationic glycopolymer complexed with siRNA; however, further research into the appropriate N:P ratio is necessary. In conclusion, RAFT polymerisation is a suitable technique for the synthesis of cationic glycopolymers for use in nucleic acid delivery. The cationic block of the polymer is able to complex with nucleic acids while the glycopolymer block is able to bind to specific lectins. Further research into carbohydrates specific binding and further modifications to increase nucleic acid delivery efficiency would be beneficial

Mammals of Bexar County, Texas

p. 47-80 ; 24 cm.Includes bibliographical references

Mammals of Aransas County, Texas

p. 165-198 : map ; 24 cm.Includes bibliographical references

Arginine Cofactors on the Polymerase Ribozyme

The RNA world hypothesis states that the early evolution of life went through a stage in which RNA served both as genome and as catalyst. The central catalyst in an RNA world organism would have been a ribozyme that catalyzed RNA polymerization to facilitate self-replication. An RNA polymerase ribozyme was developed previously in the lab but it is not efficient enough for self-replication. The factor that limits its polymerization efficiency is its weak sequence-independent binding of the primer/template substrate. Here we tested whether RNA polymerization could be improved by a cationic arginine cofactor, to improve the interaction with the substrate. In an RNA world, amino acid-nucleic acid conjugates could have facilitated the emergence of the translation apparatus and the transition to an RNP world. We chose the amino acid arginine for our study because this is the amino acid most adept to interact with RNA. An arginine cofactor was positioned at ten different sites on the ribozyme, using conjugates of arginine with short DNA or RNA oligonucleotides. However, polymerization efficiency was not increased in any of the ten positions. In five of the ten positions the arginine reduced or modulated polymerization efficiency, which gives insight into the substrate-binding site on the ribozyme. These results suggest that the existing polymerase ribozyme is not well suited to using an arginine cofactor

A literature review of constructed wetlands : a viable treatment system for acid mine drainage

Wetlands are marsh-like ecosystems exhibiting varying degrees of saturation throughout the year and usually contain a variety of aquatic plants. They have proven capabilities in treating wastewater with physical, chemical and biological processes. Wetlands, especially plant-dominated wetlands, have the capability to remove or convert large quantities of pollutants including suspended solids, metals or excess nutrients by filtration, sedimentation, plant uptake, microbial degradation and other processes. A constructed wetland (CW) is a man-made, engineered, marsh-like area designed and constructed to treat wastewater in the same manner as a natural wetland. It is a practical alternative to mechanical wastewater treatment and water quality requirements, especially in remote areas. Although the treatment of wastewater using CW has been in use for over 40 years, it is not a well-known technology outside of scientific and engineering circles. CW have advantages over mechanical wastewater treatment systems such as simplicity in operation and maintenance and relatively low capital and operating costs. The requirements for a larger land base and a lack of standardized design criteria are two disadvantages to mechanical systems. Case studies from CW systems will illustrate that reductions in concentrations of various metals and sulphates and increased pH can be achieved when acid mine drainage is treated in a constructed wetland.Non UBCUnreviewedOthe

Diversity and decentralisation for water cycle management : reflections from the Hawkesbury Water Recycling Scheme

A broad range of initiatives continue to emerge which move towards more inclusive water cycle management. These reflect a diversity of contexts, perspectives and critical issues. This paper describes the recent history of one case example, the Hawkesbury Water Recycling Scheme, and the emerging complementaries of managing both reclaimed water and stormwater. Based upon this case study, it is suggested that applications will emerge which reflect both centralised linkages as well as decentralised dimensions. This is briefly discussed in relation to contemporary concepts of common property, and conclusions are drawn regarding implications for policy and practice