ABSTRACT
From the leaves of Meliosma lepidota ssp. squamulata, megastigmane glucosides with spiro-structures and megastigmanes were isolated. Their structures were determined by X-ray crystallographic analyses and spectroscopic investigation. The absolute structures of the megastigmanes were determined by the modified Mosher's method.
Subject(s)
Cyclohexanones/chemistry , Glucosides/chemistry , Magnoliopsida/chemistry , Norisoprenoids/chemistry , Plant Leaves/chemistry , Crystallography, X-Ray , Cyclohexanones/analysis , Glucosides/analysis , Models, Molecular , Norisoprenoids/analysisABSTRACT
Yeast-based reporter assays are useful for detecting various genotoxic chemicals. We established a genotoxicity assay using recombinant strains of Saccharomyces cerevisiae, each containing a reporter plasmid with the secretory luciferase gene from Cypridina noctiluca, driven by a DNA damage-responsive promoter of the yeast RNR3 gene. This system detected the genotoxicity of methyl methanesulphonate (MMS) as sensitively as conventional yeast-based reporter assays, using the ß-galactosidase gene in a concentration-dependent manner; it also detects four other genotoxic chemicals, allowing us to monitor DNA damage easily by skipping the cell extraction process for the assay. We examined Cypridina luciferase levels induced by MMS and three antitumour agents using a set of BY4741-derived deletion mutants, each defective in a DNA repair pathway or DNA damage checkpoint. Luciferase activities were particularly enhanced in mutant strains with mms2 Δ and mag1 Δ by exposure to MMS, rad59 Δ and mlh1 Δ to camptothecin and mms2 Δ and mlh1 Δ to mitomycin C, respectively, compared with their parent strains. Enhanced reporter activities were also found in some DNA repair mutants with cisplatin. These observations suggest that this Cypridina secretory luciferase reporter assay using yeast DNA repair mutants offers convenient and sensitive detection of the potential genotoxicity of numerous compounds, including antitumour drugs and studying the mechanisms of DNA damage response in yeast.
Subject(s)
DNA Repair/drug effects , Luciferases/metabolism , Mutagenicity Tests/methods , Mutagens/toxicity , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/genetics , Genes, Reporter , Luciferases/genetics , Mutagenicity Tests/instrumentation , Saccharomyces cerevisiae/metabolismABSTRACT
Acute retinal necrosis (ARN), which is characterized by rapidly progressing peripheral retinal necrosis, is caused mainly by herpes simplex virus type 1, herpes simplex virus type 2 (HSV-2), or varicella-zoster virus. A previously healthy 3-year-old Japanese boy developed ARN in his left eye after being bruised by a milk container. HSV-2 DNA was detected in the aqueous humor of the affected eye. Serological testing suggested that the route of infection was from mother to child, although there was no past history of apparent HSV-2 infection. Childhood ARN has not been previously reported in Japan, possibly because of the low seroprevalence of HSV-2 in Japanese women. Pediatricians must be aware of this rare disease, which can affect individuals without a previous history of HSV even in a country with a low seroprevalence of HSV-2.
