SUMMARYPlants produce structurally diverse triterpenoids, which are important for their life and survival. Most triterpenoids and sterols share a common biosynthetic intermediate, 2,3-oxidosqualene (OS), which is cyclized by 2,3-oxidosqualene cyclase (OSC). To investigate the role of an OSC, marneral synthase 1 (MRN1), in planta, we characterized a Arabidopsis mrn1 knock-out mutant displaying round-shaped leaves, late flowering, and delayed embryogenesis. Reduced growth of mrn1 was caused by inhibition of cell expansion and elongation. Marnerol, a reduced form of marneral, was detected in Arabidopsis overexpressing MRN1, but not in the wild type or mrn1. Alterations in the levels of sterols and triterpenols and defects in membrane integrity and permeability were observed in the mrn1. In addition, GUS expression, under the control of the MRN1 gene promoter, was specifically detected in shoot and root apical meristems, which are responsible for primary growth, and the mRNA expression of Arabidopsis clade II OSCs was preferentially observed in roots and siliques containing developing seeds. The eGFP:MRN1 was localized to the endoplasmic reticulum in tobacco protoplasts. Taken together, this report provides evidence that the unusual triterpenoid pathway via marneral synthase is important for the growth and development of Arabidopsis.

We evaluated the ability of the ethanol extract of red ginseng (RGE) to regulate sleep architecture. Adult rats were chronically fitted with sleep-wake recording electrodes. Following post-surgical recovery, rats were habituated extensively to freely moving polygraphic recording conditions. Polygraphic signs of undisturbed sleep-wake activities were recorded for 12 h after RGE administration. Ginseng treatment produced more time in non-rapid eye movement (NREM) sleep and total sleep. The total percentage of wakefulness decreased comparably, and the number of sleep-wake cycles was reduced after 10 and 50 mg/kg RGE. RGE (10 mg/kg) administration decreased the power density of cortical electroencephalogram (EEG) d-waves (0.75-4.5 Hz) and increased a-waves (8.0-13.0 Hz) in NREM and rapid eye movement (REM) sleep. It also decreased d-wave power density during wakefulness. Although 100 mg/kg RGE showed little effect on the power densities in NREM and REM sleep, it increased d-wave and decreased q-wave (5.0-9.0 Hz) power densities during wakefulness. Thus, RGE increases spontaneous sleep and NREM sleep. Regulation of sleep architecture by RGE involves decreased d-and q-wave and increased a-wave activities according to cortical EEG.

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