Torrey Pines Institute for Molecular Studies

About: Torrey Pines Institute for Molecular Studies is a nonprofit organization based out in San Diego, California, United States. It is known for research contribution in the topics: T cell & Antigen. The organization has 2323 authors who have published 2217 publications receiving 112618 citations.

Fatty acid-specific fluorescent probes and their use in resolving mixtures of unbound free fatty acids in equilibrium with albumin

Abstract: We report the first measurements for profiling mixtures of unbound free fatty acids. Measurements utilized fluorescent probes with distinctly different response profiles for different free fatty acids (FFA). These probes were constructed by labeling site-specific mutants of the rat intestinal fatty acid binding protein (rI-FABP) with acrylodan. The probes were produced and screened by high-throughput methods, and from more than 30 000 such probes we selected six that together have sufficient specificity and sensitivity for resolving the profile of unbound FFA (FFAu) in mixtures of different FFAu. We developed analytical methods to determine the FFAu profile from the fluorescence (ratio) response of the different probes and used these methods to determine FFAu profiles for mixtures of arachidonate, linoleate, oleate, palmitate, and stearate in equilibrium with bovine serum albumin (BSA). Measurements were performed using mixtures with a range of total FFAu concentrations, including 0.9 nM, which is similar to normal plasma levels. We also measured single FFA binding isotherms for BSA and found that binding was described well by six to seven sites with the same binding constants (Kd). The Kd values for the FFA (4-38 nM) were inversely related to the aqueous solubility of the FFA. We constructed a model with these parameters to predict the FFAu profile in equilibrium with BSA and found excellent agreement between the profiles measured using the FFA probes and those calculated with this model. These results should lead to a better understanding of albumin's role in buffering FFAu and to profiling FFAu in intra- and extracellular biological fluids.

Transforming activities of trichloroethylene and proposed industrial alternatives.

Abstract: Three chlorinated hydrocarbons, proposed or already in use as industrial subsitutes for the hydrocarbon trichloroethylene, were tested for in vitro transforming potential in a Fischer rat embryo cell system (F1706), which previously has been shown to be sensitive to transformation by chemical carcinogens. Trichloroethylene and the three substitutes (1,1,1 trichloroethane, tetrachloroethylene and methylene chloride) all were found to induce transformation, the three substitutes being equal or more efficient transforming agents.

Vitrimerization: A Novel Concept to Reprocess and Recycle Thermoset Waste via Dynamic Chemistry.

Abstract: A new approach for reprocessing of existing thermoset waste is presented. This work demonstrates that unrecyclable thermoset materials can be reprocessed using the concept of associative dynamic bonding, vitrimers. The developed recycling methodology relies on swelling the thermoset network into a solution of a catalyst, which enables transesterification reactions allowing dynamic bond exchange between ester and hydroxyl groups within the thermoset network. Thermal and mechanical properties for recycled polyurethane and epoxy networks are studied and a strategy to maintain the properties of recycled materials is discussed. The developed methodology promises recycling and even upcycling and reprocessing of previously thought intractable materials. Moreover, processability of vitrimerized thermosets with common thermoplastic manufacturing methods opens up the possibility of tuning recycled networks by adding nanoparticles. This flexibility keeps the application window of recycled thermosets very broad.

Development of a rat cell line containing stably integrated copies of a lambda/lacI shuttle vector.

Abstract: A rat embryo cultured cell line was generated that carries stably integrated copies of a lambda/lacI shuttle vector, containing the lacI gene as a mutational target. After the desired treatment of the cells, this vector can be rapidly and efficiently recovered fron the cell DNA by in vitro packaging and then screnned for mutations in the lacI gene, using bacterial detection systems. The vector is identical to that integrated into the Big Blue transgenic mouse, which was developed for in vivo mutation analysis. Characterization of the cell line by fluorescence in situ hybridization showed that the phage DNA is integrated at two distinct sites on separate chromosomes at approximately 50–70 copies per cell and the cell line is polyploid. The rescue efficiency is approximately 100 000 pfu/μg of genomic DNA. To examine the ability of the cell line to detect mutations in the lacI gene, the cells were treated with 100 μg/ml of the direct-acting alkylating agent N-methyl-N-nitrosourea (MNU) for 30 min at 37°C and grown to confluence. The shuttle vector was rescued from untreated and mutagen treated cells, and spontaneous and induced mutant frequencies were determined to be 4.0 × 10−5 and 92.7 × 10−5, respectively. The cell line can be used to detect mutations in the lacI gene, followed by recovery of mutants for sequence analysis. The cell line may be valuable for short-term in vitro mutagenesis studies, oncogene and tumor suppressor studies, and DNA repair studies.