Browsing by Author "Dassarma, Shiladitya"
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Item Bioengineering Novel Floating Nanoparticles for Protein and Drug Delivery(Elsevier, 2016) Dassarma, Priya; Karan, Ram; Kim, Jong-Myoung; Pecher, Wolf T; Dassarma, ShiladityaGas vesicle nanoparticles (GVNPs) are hollow protein nanoparticles produced by Halobacterium sp. NRC-1 which are being engineered for protein delivery. To advance the bioengineering potential of GVNPs, a strain of NRC-1 deleted for the gvpC gene (ΔgvpC) was constructed and a synthetic gene coding for Gaussia princeps luciferase was fused to an abbreviated gvpC gene on an expression plasmid. When introduced into theΔgvpC strain, an active GvpC-luciferase fusion protein bound to GVNPs resulted. These results represent both a technical improvement in the GVNP display system and its expansion for the display of active enzymes.Item Halobacterium Expression System for Production of Full-Length Plasmodium falciparum Circumsporozoite Protein(Springer, 2016) Pecher, Wolf T; Kim, Jong-Myoung; Dassarma, Priya; Karan, Ram; Sinnis, Photini; Dassarma, ShiladityaWe recently developed a novel expression system employing the halophilic Archaeon Halobacterium sp. NRC-1 for scaled-up production and nanoparticle-display of antigenic proteins. Here, we have targeted the major human parasite Plasmodium falciparum circumsporozoite protein (CSP), which is of interest for formulation of a protective malaria vaccine. A codon-optimized synthetic gene coding the full-length CSP was inserted downstream of the strong promoter for gvpA, the major gas vesicle nanoparticle protein gene, in the pDRK expression vector, and as a fusion to the gvpC protein in the pSD expression vector for display on the surface of gas vesicle nanoparticles. We found that the pDRK-CSP expression plasmid programmed high-level production of full-length CSP and the pSD-CSP expression plasmid programmed production of a GvpC-CSP fusion protein, for display on gas vesicle nanoparticles. The Halobacterium sp. expression system provides a novel approach and a potentially valuable technical advancement for the production of P. falciparum CSP for malaria vaccine development.Item Inquiry-driven Teaching & Learning Using the Archaeal Microorganism Halobacterium NRC-1(University of California Press, 2016) Dassarma, Priya; Tuel, Kelley; Nierenberg, Susan Dean; Phillips, Tony; Pecher, Wolf T; Dassarma, ShiladityaAccess to microorganisms in the classroom is essential for teaching fundamental concepts of life sciences, yet most are neither safe nor accessible for classroom instruction. Halobacterium NRC-1, a member of the Domain Archaea, is ideal for engaging students through inquiry-based teaching and learning in the classroom. We introduce this colorful model microbe and provide many ways in which it can be used for experiential learning, including life in extreme environments, basic microbiology skills, action of antibiotics, genotype-phenotype connection, genomics and bioinformatics, and applications in biotechnology.Item Microneedle-Assisted Skin Permeation by Non-toxic Bioengineerable Gas Vesicle Nanoparticles(American Chemical Society, 2017) Andar, Abhay; Karan, Ram; Pecher, Wolf T; Dassarma, Priya; Hedrich, William; Stinchcomb, Audra L; Dassarma, ShiladityaGas vesicle nanoparticles (GVNPs) are hollow, buoyant protein organelles produced by the extremophilic microbe Halobacterium sp. NRC-1 and are being developed as bioengineerable and biocompatible antigen and drug-delivery systems (DDS). Dynamic light scattering measurements of purified GVNP suspensions showed a mean diameter of 245 nm. In vitro diffusion studies using Yucatan miniature pig skin showed GVNP permeation to be enhanced after MN-treatment compared to untreated skin. GVNPs were found to be non-toxic to mammalian cells (human kidney and rat mycocardial myoblasts). These findings support the use of GVNPs as DDS for intradermal/transdermal permeation of protein- and peptide-based drugs.Item Recent Desiccation-Related Ecosystem Changes at Lake Abert, Oregon: A Terminal Alkaline Salt Lake(Elsevier, 2016) Larson, Ron; Eilers, Joseph; Kreuz, Keith; Pecher, Wolf T; Dassarma, Shiladitya; Dougill, SteveLake Abert, a terminal alkaline salt lake in south central Oregon, has been a key staging area for migratory waterbirds along the Pacific Flyway. In 2014, the lake shrank to about 5% of its maximum size, and its salinity increased from 75 g · L–1 to 250 g · L–1. This resulted in a major ecosystem shift from one dominated at higher trophic levels by invertebrates and waterbirds to one composed primarily of hypersaline-adapted microbes. A large variety of halophilic bacteria and archaea were also detected using 16S rRNA metagenomic sequence analysis. The loss of prey and staging habitat for migratory waterbirds was especially pronounced for Eared Grebe, Red-necked Phalarope, and Wilson’s Phalarope, all of which feed on brine shrimp and alkali flies. The last time the lake was in this state was nearly a century ago during the Dust Bowl of the 1930s, which was a once-in-500-years drought. To understand the causes of the current event, we examined hydrological, climatic, and biological data. The primary cause of the event appears to have been the combined effects of upstream water diversions and lower river flows that were exacerbated by a moderate decade-long drought and elevated evaporation rates.