Association Between Individual Differences in Dichotomous Thinking and Current and Childhood High-Crime Environments.

The way people perceive the things around them is closely related to living in a complex and challenging social environment. Dichotomous thinking (preference for dichotomy, dichotomous belief, and profit-and-loss thinking), which classifies things in a simple way, can be useful in dangerous and resource-limited environments. However, based on prior studies, people's manner of perceiving things may have developed as a response to the harshness of their childhood environment, and may not be related to their current environment. Therefore, we examined the relationship between individual differences in dichotomous thinking and high-crime environments as indicators of environmental harshness. We assessed dichotomous thinking in 41,284 Japanese residents using large-scale data from the Human Information Database FY19 compiled by NTT DATA Institute of Management Consulting, Inc. The fixed effects regression model showed that, after controlling for age, high-crime environment of the residents' childhood was associated with dichotomous thinking, with the exception of dichotomous belief. On the other hand, their current environment of crime was not associated. In sum, our research suggests that people's dichotomous thinking tendency may be a form of adaptation to the harshness of their childhood environment rather than their current one.

A validation of the Japanese adaptation of the Big Five Inventory-2.

The purpose of this study was to adapt a Japanese version of the Big Five Inventory-2 (BFI-2-J) to examine its factor structure, reliability, validity, and measurement invariance. The BFI-2-J assesses five domains and 15 facets of the Big Five personality traits. We analyzed two datasets: 487 Japanese undergraduates and 500 Japanese adults. The results of the principal component analysis and confirmatory factor analysis revealed that the domain-facet structure of the BFI-2-J was similar to that of other language versions. The reliability of the BFI-2-J is sufficient. The correlation coefficients between the BFI-2-J and the other Big Five and self-esteem measures supported convergent and discriminant validity. Moreover, we confirmed measurement invariance across age and sex groups in domain-level and facet-level models. The results suggest that the BFI-2-J is a good instrument for measuring the Big Five personality traits and their facets in Japan. The BFI-2-J is expected to be useful in Japanese personality research and international comparative research.

The contribution of Arabidopsis homologs of L-gulono-1,4-lactone oxidase to the biosynthesis of ascorbic acid.

To clarify the involvement of seven Arabidopsis homologs of rat L-gulono-1,4-lactone (L-GulL) oxidase, AtGulLOs, in the biosynthesis of L-ascorbic acid (AsA), transgenic tobacco cells overexpressing the various AtGulLOs were generated. Under treatment with L-GulL, the levels of total AsA in three transgenic tobacco cell lines, overexpressing AtGulLO2, 3, or 5, were significantly increased as compared with those in control cells.

Conversion of L-galactono-1,4-lactone to L-ascorbate is regulated by the photosynthetic electron transport chain in Arabidopsis.

In this study we focused on the effects of light irradiation and the addition of L-galactono-1,4-lactone (L-GalL) on the conversion of exogenous L-GalL to L-ascorbate (AsA) and the total AsA pool size in detached leaves of Arabidopsis plants and transgenic plants expressing the rat L-gulono-1,4-lactone oxidase gene. Increases in the total AsA level in L-GalL-treated leaves depended entirely on light irradiation. Treatment with an inhibitor of photosynthetic electron transport together with L-GalL reduced the increase in total AsA under light. Light, particularly the redox state of photosynthetic electron transport, appeared to play an important role in the regulation of the conversion of L-GalL to AsA in the mitochondria, reflecting the cellular level of AsA in plants.

Light regulation of ascorbate biosynthesis is dependent on the photosynthetic electron transport chain but independent of sugars in Arabidopsis.

It has been known that leaves exposed to high light contain more L-ascorbic acid (AsA) than those in the shade. However, the mechanism of the light regulation of the AsA pool size in plants is largely unknown. In this work, the relationship between gene expression levels related to AsA biosynthesis and photosynthesis have been studied. When 2-week-old Arabidopsis plants grown under a 16 h daily photoperiod were moved into the dark, the AsA level in the leaves was decreased by 91% in 72 h, whereas it increased by 171% in the leaves of plants exposed to continuous light during the same period. Among the several enzymes of the AsA biosynthesis pathway, the transcript levels of GDP-D-mannose pyrophosphorylase, L-galactose 1-P phosphatase, L-galactono-1,4-lactone dehydrogenase, and the VTC2 gene were down-regulated in the dark. Treatment with inhibitors of photosynthesis, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and atrazine, arrested a rise in the AsA pool size accompanying the decrease in the transcript levels of the genes of the above enzyme in the leaves. When the plants were transferred to a medium containing 0.5% (w/v) sucrose, the photosynthesis activities and the leaf AsA levels were lowered even under exposure to light compared with those in plants on the medium without sucrose. In contrast, the AsA level in leaves of the sugar-insensitive Arabidopsis mutant abi4/sun6 was unaffected by external sucrose. No significant difference in the expression profiles for AsA biosynthesis enzymes was observed between the wild-type and mutant plants by sucrose feeding. The results suggest that photosynthetic electron transport of chloroplasts is closely related to AsA pool size regulation in leaves.

Feedback inhibition of spinach L-galactose dehydrogenase by L-ascorbate.

We have studied the enzymological properties of L-galactose dehydrogenase (l-GalDH), a key enzyme in the biosynthetic pathway of l-ascorbate (AsA) in plants. L-GalDH was purified approximately 560-fold from spinach leaves. The enzyme was a homodimer with a subunit mass of 36 kDa. We also cloned the full-length cDNA of spinach L-GalDH, which contained an open reading frame encoding 322 amino acid residues with a calculated molecular mass of 35,261 Da. The deduced amino acid sequence of the cDNA showed 82, 79 and 75% homology to L-GalDH from kiwifruit, apple and Arabidopsis, respectively. Recombinant enzyme expressed from the cDNA in Escherichia coli showed L-GalDH activity. Southern blot analysis revealed that the spinach L-GalDH gene occurs in a single copy. Northern blot analysis suggests that L-GalDH is expressed in different organs of spinach. The purified native L-GalDH showed high specificity for L-galactose with a Km of 116.2+/-3.2 microM. Interestingly, spinach L-GalDH exhibited reversible inhibition by AsA, the end-product of the biosynthetic pathway. The inhibition kinetics indicated a linear-competitive inhibition with a Ki of 133.2+/-7.2 microM, suggesting feedback regulation in AsA synthesis in the plant.