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Biomedical subjects

B Talbot

Publications and source records attributed to B Talbot.

35 records · Page 2Linked to original sources
PubMed1986

Production and characterization of monoclonal antibodies specific for the functional domains of poly(ADP-ribose) polymerase.

Monoclonal antibodies were developed against poly(ADP-ribose) polymerase and analyzed for their reactivity against the NAD+- and DNA-binding fragments. Two fusions were performed to obtain hybridomas and the resulting anti-poly(ADP-ribose) polymerase antibodies were further screened by characterization of their immunoglobulin light chains. Five different hybridomas were isolated which produced different immunoglobulin light chains, all of which were specific for poly(ADP-ribose) polymerase. The specificities of these antibodies were determined by immunoblotting against the purified poly(ADP-ribose) polymerase, its autodegradation fragments, and the fragments prepared by limited proteolysis with chymotrypsin and papain. These fragments have been suggested to contain the NAD+-binding site, the DNA-binding site, and the automodification site, respectively. All the monoclonal antibodies reacted with the 116 kdalton (kDa) band corresponding to the purified enzyme. Four antibodies reacted exclusively with antigenic site(s) on the 46-kDa fragment which contains the DNA-binding site. A fifth antibody reacted exclusively with a clearly different antigenic site on the 74- and 54-kDa fragments which possess the NAD+ (substrate) binding site. The immunoreactivity with the major autodegradation products (69- and 46-kDa fragments) of the purified enzyme confirms this difference between the two groups of antibodies. The 22-kDa fragment corresponding to the auto-modification site does not show any immunoreactivity with the antibodies.

Animals↗
PubMed1984

Immunological and genetic characterization of 2-deoxygalactose-resistant, galactokinase-deficient mutants of Chinese hamster cells: evidence for structural mutations at the galK locus.

Ten independent mutants resistant to 2-deoxygalactose and without any detectable galactokinase activity (null-galactokinase mutations) were isolated from mutagenized Chinese hamster somatic cells. They were analyzed for the presence of serologically cross-reacting material (CRM) with antiserum generated against highly purified Chinese hamster galactokinase. All 10 mutants contain cross-reacting material (i.e., were CRM+), indicating that all the mutations affect the correct expression of a product of the galactokinase structural gene. Complementation analysis among them shows that the 10 mutations fall in one functional genetic unit.

Animals↗
PubMed1982

Isolation, purification and partial characterization of galactokinase from Chinese hamster liver.

1. Galactokinase was purified from Chinese hamster liver. The purification process consisted of an initial biphasic partition separation followed by column chromatography on DEAE-cellulose. DEAE-Sephadex, Sephacryl S-200 and hydroxyapatite. 2. The enzyme was stabilized during the purification procedure by the inclusion of 10% glycerol, 1 mM phosphate and 20 mM beta-mercaptoethanol in all the buffer solutions. 3. Chromatography on hydroxyapatite separated two forms of galactokinase, one of which was purified to homogeneity using gel electrophoresis. 4. The purified galactokinase has a mol. wt of approximately 60,000 as determined by SDS gel electrophoresis and molecular sieving column chromatography. 5. The pH optimum is 7.4 and the Km for galactose is 1.16 x 10(-4) M.

Animals↗
PubMed1978

Alcohol dehydrogenase mutants of Chinese hamster somatic cells resistant to allyl alcohol.

Alcohol dehydrogenase (alcohol: NAD oxidoreductase, E.C. 1.1.1.1.) mutants of Chinese hamster somatic cells were isolated as resistant to allyl alcohol (ALLR). The ALLR phenotypes of the mutant clones were reproducible with high fidelity and stable over long intervals of growth in the absence of the selecting drug. Several mutants, Adh-1, Adh-2, Adh-9 and Adh-13, resistant to allyl alcohol were characterized. They have between 15 and 40% of the alcohol dehydrogenase activity of the wild-type cell lines. This phenotype is therefore a useful marker to analyze gene segregation of somatic cell mutations and to study the expression of the genes involved in the metabolism of ethanol in mammalian cells.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Properties of three monoclonal antibodies that recognize an 80-kDa phytohemagglutinin-binding glycoprotein from porcine lymphocytes.

Monoclonal antibodies (mAbs) directed against porcine splenocyte phytohemagglutinin receptor glycoproteins were produced in BALB/c mice. Three antibody-producing, stable hybridomas were cloned and expanded in the peritoneal cavity of BALB/c mice. The mAbs (A7, B1, and H3) were purified and belong to the IgG2 subclass of immunoglobulins (kappa light chain). Each 125I-labeled mAb bound to purified porcine splenocytes with an (apparent) affinity KA congruent to 10(8) M-1 (Scatchard analysis). The number of (apparent) binding sites was 5 x 10(4) sites/cell in the case of B1 and H3, and approximately 15 x 10(4) sites/cell for A7. Immunoprecipitation experiments showed that the three mAbs recognized a single antigenic protein of Mr 80 kilodaltons (gp80). In addition, each mAb recognized a different epitope of gp80, as observed by Western blot analyses. Assessment of the relative ability of anti-gp80 mAbs to stimulate porcine splenocytes as determined by [3H]thymidine incorporation showed weak (A7 and B1) or no (H3) mitogenic activity. Cross-linked anti-gp80 mAbs were not mitogenic, except in the case of B1. In contrast, each anti-gp80 mAb (cross-linked or untreated) showed synergistic mitogenic properties when used in combination with a suboptimal concentration of phytohemagglutinin. The mechanism involved in this synergistic effect is discussed.

Animals↗
PubMedDate not supplied

Development of the National Institutes of Health Guidelines for Recombinant DNA Research.

Recombinant DNA is a technique of major importance in basic biomedical research and, increasingly, in industrial applications. Although the risks of this research remain hypothetical, scientists working in the field have spearheaded discussions of safety. The original National Institutes of Health (NIH) Guidelines for Recombinant DNA Research were issued in June 1976. They assigned each type of recombinant DNA experiment a specific level of "physical containment" and of "biological containment." Responsibility for overseeing the application of the guidelines belongs to the NIH Recombinant DNA Advisory Committee (RAC)--composed of scientists and laymen, including non-voting representatives from many Federal agencies--and local institutional biosafety committees at each university where recombinant DNA research is conducted. The NIH guidelines were subsequently adopted by other Federal agencies, but congressional proposals aimed at extending the guidelines to private industry did not result in national legislation. Some States and localities regulate recombinant DNA research, however, and many private companies have voluntarily submitted information on their recombinant DNA work for RAC and NIH approval. The NIH guidelines underwent a major revision in December 1978 and have been revised approximately every 3 months since then. NIH supports experiments to assess recombinant DNA risks and publishes and updates a plan for a risk assessment program.

Containment of Biohazards↗