Immunohistochemical Detection of Carcinogen-DNA Adducts and DNA Repair in Mouse Skin

4-Hydroxyaminoquinoline 1-oxide (4HAQO) and (±)-trans-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydroben-zo[a]pyrene (BP-DE)-DNA adducts were immunohisto-chcmically demonstrated in the nuclei of mouse skin using antibodies directed against carcinogen (4HAQO or BP) modified DNA. The specificity of the immunostaining was confirmed by several tests, including preincubation of the antibody with carcinogen modified DNA or related molecules, and digestion of the sections with DNase.Subcutaneous injection of 4HAQO dissolved in isotonic solution into an isolated portion of the mouse skin clamped off with ring-shaped forceps resulted in dose-dependent generation of DNA adducts in the nuclei of epithelial cells, fibroblasts, and panniculus carnosus cells. BP-DNA adducts could also be similarly detected dose-dependently in the nuclei of skin cells after local application of BP-DE. Nuclear staining was absent in animals injected with isotonic solution alone, and the intensity of staining correlated well with the level of unscheduled DNA synthesis (UDS) demonstrated autoradiographically after treatment with 4HAQO. Killing of mice at different time points after a single injection of 4HAQO revealed a gradual decrease in the intensity of the staining. Thus the postulated generation and repair of DNA adducts can be followed at the cellular level using the presently described method. J Invest Dermatol 92:275S–279S, 198

Heme-dependent autophosphorylation of a heme sensor kinase, ChrS, from Corynebacterium diphtheriae reconstituted in proteoliposomes

AbstractCorynebacterium diphteriae employs the response regulator, ChrA, and the sensor kinase, ChrS, of a two-component signal transduction system to utilize host heme iron. Although ChrS is predicted to encode a heme sensor, the sensing mechanism remains to be characterized. In this report, ChrS expressed in Eshcherichia coli membranes was solubilized and purified using decylmaltoside. ChrS protein incorporated into proteoliposomes catalyzed heme-dependent autophosphorylation by ATP. Other metalloporphyrins and iron did not stimulate kinase activity. The UV–Vis spectrum of hemin in the ChrS–proteoliposomes indicated that heme directly interacts with ChrS. This is the first functional reconstitution of a bacterial heme-sensing protein

Promoting Willingness to Communicate in Classroom Culture : Through an Analysis of Small Talk

departmental bulletin pape

Bilateral herpes simplex keratitis in a patient with chronic graft-versus-host disease

Takahiko Hayashi1, Misaki Ishioka2, Norihiko Ito1, Yoko Kato1, Hisashi Nakagawa3, Hiroshi Hatano4, Nobuhisa Mizuki11Department of Ophthalmology, Yokohama City University School of Medicine, Yokohama, Kanagawa, Japan; 2Ryogoku Eye Clinic, Tokyo, Japan; 3Tokushima Eye Clinic, Higashimurayama-shi, Tokyo, Japan; 4Lumine Hatano Eye Clinic, Fujisawa, Fujisawa-shi, Kanagawa, JapanPurpose: To describe a case of bilateral herpes simplex keratitis accompanying chronic graft-versus-host disease (GVHD).Design: Observational case report.Case report: An 11-year-old boy with myelocytic leukemia underwent allogeneic bone marrow transplantation. He developed symptoms of the skin, eyes, and mouth, and lip biopsy indicated chronic GVHD. Persistent keratitis with corneal filaments and neovascularization was noted in both eyes. Sodium hyaluronate, autoserum, and 0.1% fluorometholone eyedrops were instilled for approximately 2 years to treat this keratitis, and there were no other ocular changes. Bilateral herpes simplex keratitis developed with geographic ulcers after topical betamethasone therapy, but responded to acyclovir ointment.Conclusions: Herpes keratitis should be considered in the differential diagnosis of bilateral keratitis in patients with reduced immunocompetence. During the course of chronic GVHD, corneal herpes may occur, so ocular treatment with topical corticosteroids should be managed by an ophthalmologist to monitor sight-threatening conditions such as corneal herpes.Keywords: chronic graft-versus-host disease, bone marrow transplant, corneal herpes, bilateral herpes simplex keratitis, dry eye

Rpd3/CoRest-mediated activity-dependent transcription regulates the flexibility in memory updating in Drosophila

Consolidated memory can be preserved or updated depending on the environmental change. Although such conflicting regulation may happen during memory updating, the flexibility of memory updating may have already been determined in the initial memory consolidation process. Here, we explored the gating mechanism for activity-dependent transcription in memory consolidation, which is unexpectedly linked to the later memory updating in Drosophila. Through proteomic analysis, we discovered that the compositional change in the transcriptional repressor, which contains the histone deacetylase Rpd3 and CoRest, acts as the gating mechanism that opens and closes the time window for activity-dependent transcription. Opening the gate through the compositional change in Rpd3/CoRest is required for memory consolidation, but closing the gate through Rpd3/CoRest is significant to limit future memory updating. Our data indicate that the flexibility of memory updating is determined through the initial activity-dependent transcription, providing a mechanism involved in defining memory state