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Biomedical subjects

M L Dreher

Publications and source records attributed to M L Dreher.

6 recordsLinked to original sources
PubMed1991

Colony assays for antibody fragments expressed in bacteria.

This paper describes procedures for the detection and selection of bacterial colonies expressing antibody fragments of desired antigen specificity. Fab and Fv fragments are detected in a filter assay in which bacterial colonies are grown on a master filter in contract with a second, antigen-coated filter. Ab fragments diffusing onto the second filter bind antigen directly and specifically and are detected with a monoclonal antibody directed against a myc-tag sequence fused to the carboxy-terminal end of the light chain or heavy chain (direct assay). Single-chain Fv (scFv) in which the VH and V1 sequences are joined by a short linker peptide are detected by a modified procedure in which scFv are immobilized on filters coated with the anti-myc-tag sequence and subsequently detected by specific binding to radiolabeled antigen (indirect assay). A single positive bacterial colony expressing antigen-specific Fv (or scFv) can be recovered among at least 10,000 negative colonies using the procedures described. The direct assay has been successfully used to discriminate Fv fragments which express point mutations known to increase the binding affinity of antibodies to the hapten 2-phenyl-oxazolone. The procedures described may thus prove generally useful for the selection of antigen-specific clones expressed in bacteria and/or higher-affinity variants of such antibodies.

Antibodies↗
PubMed1991

Filter screening of antibody Fab fragments secreted from individual bacterial colonies: specific detection of antigen binding with a two-membrane system.

Recently antibody fragments have been expressed in a functional form from bacteria. We have devised a simple method to detect the binding of antigen to antibody Fab fragments secreted by bacterial colonies. Bacteria harboring plasmid vectors that direct the secretion of Fab fragments into the bacterial periplasm are grown on one membrane. The secreted fragments are allowed to diffuse to a second "capture" membrane coated with anti-globulin, and are probed with antigen. Using enzyme or colloidal gold conjugates, the binding of antigen is detected on the second membrane as a colored spot. The colonies can be regrown on the first membrane, and the antigen binding signal on the second membrane is free of noise contributed by bacterial debris.

Antigen-Antibody Reactions↗
PubMed1987

Down-regulation of phorbol diester binding to NG115-401L neuronal cells is dependent on structure, concentration and time.

The down-regulation of [3H]PDBu binding to a neural cell line, NG115-401L, has been examined in response to two biologically active phorbol diesters, PDBu and PMA. Chronic treatment with PDBu or PMA causes a concentration- and time-dependent loss of specific [3H]PDBu binding. The action of PMA is biphasic with respect to both concentration and time dependence.

Caenorhabditis elegans Proteins↗
PubMed1984

Starch digestibility of foods: a nutritional perspective.

Dietary starch varies greatly in digestibility and its effects on the utilization of other nutrients. The variation appears to be due to differences in starch components and their crystallinity. Processing treatments, storage conditions, chemical modification, and genetic breeding influence the digestibility of starch. Cereal starches are generally more digestible than root/tuber and legume starches. Although cooking often significantly improves the digestibility of poor and intermediately digestible starches, some foods such as bananas with starches of these types are consumed uncooked. The efficient digestion of starch is especially important to specific groups of people such as infants under 6 months of age. Ruminants must also be provided with highly digestible starch to assure maximum production efficiency. Poor digestibility of starch may have negative effects on the utilization of protein and minerals but is likely to have positive effects on the availability of certain vitamins. Decreases in the rate of starch digestion may have therapeutic application. Most clinical studies have reported that starch blockers do not elicit a significant decrease in the digestion of starch in humans. Much remains to be learned, clarified, and understood about starch digestion and its effects on diabetes and weight control.

Animals↗