The effects of calystegines isolated from edible fruits and vegetables on mammalian liver glycosidases

The polyhydroxylated nortropane alkaloids called calyste-ginesoccur in many plants of the Convolvulaceae, Solanaceae, andMoraceae families. Certain of these alkaloids exhibit potentinhibitory activities against glycosidases and the recentlydemonstrated occurrence of calystegines in the leaves, skins,and sprouts of potatoes (Solatium tuberosum), and in the leavesof the eggplant (S.melongena), has raised concerns regardingthe safety of these vegetables in the human diet. We have surveyedthe occurrence of calystegines in edible fruits and vegetablesof the families Convolvulaceae, Solanaceae, and Moraceae byGC-MS. Calystegines A3, B1, B2, and C1 were detected in allthe edible fruits and vegetables tested; sweet and chili peppers,potatoes, eggplants, tomatoes, Physalis fruits, sweet potatoes,and mulberries. Calystegines B1 and C1 were potent competitiveinhibitors of the bovine, human, and rat β-glucosidaseactivities, with K₁ values of 150, 10, and 1.9 µM, respectivelyfor B1 and 15,1.5, and 1 µM, respectively, for C1. CalystegineB2 was a strong competitive inhibitor of the -galactosidaseactivity in all the livers. Human β-xylosidase was inhibitedby all four nortropanes, with calystegine C1 having a K₁ of0.13 µM. Calystegines A3 and B2 selectively inhibitedthe rat liver β-glucosidase activity. The potent inhibitionof mammalian β-glucosidase and -galactosidase activitiesin vitro raises the possibility of toxicity in humans consuminglarge amounts of plants that contain these compounds. edible plants calystegines glycosidase inhibitors bovine, human, and rat liver     

Binding mode of ecdysone agonists to the receptor: comparative modeling and docking studies

Three-dimensional structure models of the ligand-binding domain of the ecdysone receptor of Heliothis virescens were built by the homology modeling technique from the crystal structures of nuclear receptors. Two models were created based both on known ligand-binding domain structures of the receptors with the highest sequence identity to the ecdysone receptor, and on those of steroid hormone receptors. The latter model, which was found to have better stereochemical quality and be in good agreement with the binding of the steroidal framework of the endogenous agonist 20-hydroxyecdysone, was used for docking studies. The docking of 20-hydroxyecdysone to the receptor model revealed that the ligand molecule can interact with the receptor in a similar manner to other steroid hormone-receptor complexes. The docking of a dibenzoylhydrazine agonist, chromafenozide, was performed based on the correspondences between the molecule and 20-dydroxyecdysone expected by molecular comparison. The interactions of the ligands with the receptor in the complexes modeled were investigated and found to be consistent with known structure-activity relationships.     

Axenic culture of <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> using antibiotics

The rotifer Brachionus plicatilis culture is composed of complex microcosms including bacteria, protozoans, algae, and fungi. Previous studies reported methods to establish axenic rotifer cultures, but further refinement of these techniques is needed, for molecular biological research which requires pure culture to isolate nucleic acids from rotifers only. In order to render rotifer culture axenic, we tested five antibiotics: ampicillin (Amp), chloramphenicol (Cp), kanamycin (Km), nalidixic acid (Na), and streptomycin (Sm) at 30–100 μg/ml. Except for Cp, which reduces rotifer reproduction, all other antibiotics at the tested concentrations did not affect rotifer reproduction or show any toxic effects. A rotifer disinfection method was finally established by treating the resting eggs with 0.25% (w/v) sodium hypochlorite (NaOCl) for 3 min, washing with sterilized sea water, and then exposing the neonates to an Amp, Km, Na, and Sm mixture. Using four nutrient media, we confirmed that this protocol renders the rotifer culture bacterial and fungus free. The axenic rotifer culture generated here is useful not only for genetic analysis of Brachionus plicatilis, but for studying the rotifer life cycle without bacterial influence.     

Ethical Obligations in the Face of Dilemmas Concerning Patient Privacy and Public Interests: The Sasebo Schoolgirl Murder Case

A murder case that had some features in common with the Tarasoff case occurred in Sasebo City, Japan, in 2014. A 15‐year‐old high school girl was murdered and her 16‐year‐old classmate was arrested on suspicion of homicide. One and a half months before the murder, a psychiatrist who had been examining the girl called a prefectural child consultation centre to warn that she might commit murder, but he did not reveal her name, considering it his professional duty to keep it confidential. Article 134 of the Japanese Criminal Law states that doctors should not disclose patient information obtained in clinical practice without a legitimate reason, but the Japanese Supreme Court has not specified what constitutes a legitimate reason. Mass media and commentators suggested that the murder could have been prevented if the psychiatrist had disclosed the girl's name to the authorities or had isolated her coercively in a psychiatric ward. However, the authors disagree with such claims. This article discusses obligations imposed on concerned individuals and third party members in cases involving ethical dilemmas regarding patient confidentiality and information disclosure. It is concluded that everyone should fulfill their obligations to prevent such tragedies and one should judge the appropriateness of others’ actions based not on the consequences of their actions, but on the processes used to decide on a course of action and their commitment. It is necessary for us to establish a society in which concerned parties can do what they think is ethically best without fearing ungrounded charges.     

Analysis of genes induced in peripheral nerve after axotomy using cDNA microarrays

One of the most striking features of neurons in the mature peripheral nervous system is their ability to survive and to regenerate their axons following axonal injury. To perform a comprehensive survey of the molecular mechanisms that underlie peripheral nerve regeneration, we analyzed a cDNA library derived from the distal stumps of post-injured sciatic nerve which was enriched in non-myelinating Schwann cells using cDNA microarrays. The number of up- and down-regulated genes in the transected sciatic nerve was 370 and 157, respectively, of the 9596 spotted genes. In the up-regulated group, the number of known genes was 216 and the number of expressed sequence tag (EST) sequences was 154. In the down-regulated group, the number of known genes was 103 and that of EST sequences was 54. We obtained several genes that were previously reported to be involved in regeneration of the injured neurons, such as cathepsin D, ninjurin 1, tenascin C, and co-receptor for glial cell line-derived neurotrophic factor family of trophic factors. In addition to unknown genes, there seemed to be a lot of annotated genes whose role in nerve regeneration remains unknown.