Bob Johnsen

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The guanine modification 7,8-dihydro-8-oxoguanine (8-oxoG) is a potent premutagenic lesion formed spontaneously at high frequencies in the genomes of aerobic organisms. We have characterized a human DNA repair glycosylase for 8-oxoG removal, hOGH1 (human yeast OGG1 homologue), by molecular cloning and functional analysis. Expression of the human cDNA in a(More)
Duchenne Muscular Dystrophy is an inherited muscle degeneration disease for which there is still no efficient treatment. However, compounds active on the disease may already exist among approved drugs but are difficult to identify in the absence of cellular models. We used the Caenorhabditis elegans animal model to screen a collection of 1000 already(More)
We report here a highly significant positive correlation observed when the factor VII-phospholipid complex (the phospholipase-C sensitive component of factor VII) in plasma was tested in a specific factor VII system and in Normotest (p less than 0.0001). The Normotest system, which is sensitive to variations in coagulation activity within the normal range,(More)
Purified phospholipase C from Bacillus cereus caused a significant loss in the procoagulant activity of thromboplastin preparations from man, rabbit, sheep, cow, rat and mouse. However, marked differences were observed with respect to the degree of inactivation. Rat, mouse, bovine and one type of rabbit preparations (prepared from acetone powdered brain)(More)
Previous experiments (Gollub et al. [10]. Giercksky et al.) have shown that phospholipase C (PLC) has a protective effect on rats and rabbits receiving thromboplastin infusions. As a step towards the possible use of PLC in humans, we have investigated further the use of PLC in rabbits. Infusions of human or rabbit thromboplastin caused a rapid fall in(More)
Caenorhabditis elegans strains carrying stress-reporter green fluorescent protein transgenes were used to explore patterns of response to metals. Multiple stress pathways were induced at high doses by most metals tested, including members of the heat shock, oxidative stress, metallothionein (mtl) and xenobiotic response gene families. A mathematical model(More)
In an effort to speed the rate of discovery in space biology and medicine NASA introduced the now defunct model specimen program. Four nations applied this approach with C. elegans in the ICE-FIRST experiment. Here we review the standardized culturing as well as the investigation of muscle adaptation, space biology radiation, and gene expression in response(More)
Using light to modulate biochemical agents in living organisms has a significant impact on photodynamic therapy and drug release. We demonstrate that a photoresponsive system can reversibly induce paralysis in nematodes as a model for living organisms when two different wavelengths of light are used to toggle the molecular switch between its two structural(More)