Biomedical subjects

Pamela Sears

Publications and source records attributed to Pamela Sears.

5 recordsLinked to original sources

PubMed2005

Structure-activity relationships of bivalent aminoglycosides and evaluation of their microbiological activities.

A library of 4,5- and 4,6-linked bivalent aminoglycoside (AMG) antibiotics consisting of neamine and nebramine pharmacophores have been synthesized. We probed the effect of the linker on antibiotic activity with a series of selected synthetic analogues with varied length and substituents. A number of compounds demonstrated in vitro activity against several bacterial strains and showed activity against drug resistant strains of Pseudomonas aeruginosa. Among the compounds prepared, analogues 12a-d were novel 4,6-linked AMGs containing the nebramine pharmacophore. In addition the lead compound OPT-11 possessed an ED(50) of <or=5mg/kg in a Staphylococcus aureus ATCC 29213 mouse protection model.

Aminoglycosides↗

PubMed2004

Synthesis and high-throughput screening of N-acetyl-beta-hexosaminidase inhibitor libraries targeting osteoarthritis.

C1 Nitrogen iminocyclitols are potent inhibitors of N-acetyl-beta-hexosaminidases. Given hexosaminidases' important roles in osteoarthritis, we developed two straightforward and efficient syntheses of C1 nitrogen iminocyclitols from two readily available starting materials, D-mannosamine hydrochloride and the microbial oxidation product of fructose. A diversity-oriented synthetic strategy was then performed by coupling these core structures with various aldehydes, carboxylic acids, and alkynes to generate three separate libraries. High-throughput screening of the generated libraries with human N-acetyl-beta-hexosaminidases produced only moderate inhibitory activities. However, the synthetic approach and screening strategy for these compounds will be applied to develop new potent inhibitors of human N-acetyl-beta-hexosaminidases, particularly when combined with the structural information of these enzymes.

Enzyme Inhibitors↗

PubMed2004

Glyco-optimization of aminoglycosides: new aminoglycosides as novel anti-infective agents.

Glyco-optimization (OPopS) of aminoglycosides has been performed by replacing the existing sugar moiety with a variety of sugar derivatives. Glycosylation of the 6-position of nebramine provided a library of novel 4,6-linked aminoglycosides (AMGs). Among them, compounds 8b,g,i,l, and 8u with 2"-amino, 2",3"-diamino, 2",4"-diamino, 3",4"-diamino, 3"-amino groups, respectively, showed significant antimicrobial activity against Gram-(+) and -(-) bacteria. Several were particularly potent against Pseudomonus aeruginosa with MICs in the 1-2 microg/mL range.

Aminoglycosides↗

PubMed2004

A three-fluorophore FRET assay for high-throughput screening of small-molecule inhibitors of ribosome assembly.

In one of the first steps of prokaryotic ribosome assembly, the ribosomal protein S15 binds to a three-way junction in the central domain of the 16S rRNA. Binding causes a conformational change that is required for subsequent binding events. Using a novel fluorescence resonance energy transfer assay with three fluorophores, two on the RNA and one on the S15 protein, small-molecule libraries can be screened for potential inhibitors of this initial step in ribosome assembly. The employment of three fluorophores allows both the conformational change of the RNA and the binding of S15 to be monitored in a single assay.

Aminoglycosides↗

PubMed2002

Saccharide display on microtiter plates.

New insight into the importance of carbohydrates in biological systems underscores the need for rapid synthetic and screening procedures for them. Development of an organic synthesis-compatible linker that would attach saccharides to microtiter plates was therefore undertaken to facilitate research in glycobiology. Galactosyllipids containing small, hydrophobic groups at the anomeric position were screened for noncovalent binding to microtiter plates. When the lipid component was a saturated hydrocarbon between 13 and 15 carbons in length, the monosaccharide showed complete retention after aqueous washing and could be utilized in biological assays. This alkyl chain was also successfully employed with more complex oligosaccharides in biological assays. In light of these findings, this method of attachment of oligosaccharides to microtiter plates should be highly efficacious to high-throughput synthesis and analyses of carbohydrates in biological assays.

Carbohydrate Conformation↗