The Gene Encoding Flavanone 3-Hydroxylase is Expressed Normally in the Pale Yellow Flowers of the Japanese Morning Glory Carrying the speckled Mutation Which Produce Neither Flavonol nor Anthocyanin but Accumulate Chalcone, Aurone and Flavanone

The Japanese morning glory carrying the recessive mutable speckledallele with the dominant speckled-activator bears colorlessflowers with fine and round colored spots distributed over thecorolla whereas the plant without the speckled-activator producespale yellow flowers. Previous chemical analysis has indicatedthat a mutation in the gene for flavanone 3-hydroxylase (F3H)is a likely candidate for the speckled allele. However, theF3HmRNA without sequence alteration accumulates normally inthe pale yellow flowers, indicating that the speckled alleleis neither the F3H gene nor a regulatory gene acting on theF3H gene expression. (Received April 4, 1997; Accepted June 2, 1997)     

The Schizosaccharomyces pombe cdc6 gene encodes the catalytic subunit of DNA polymerase δ

The cdc6 mutants of Schizosaccharomyces pombe have been classified as being defective in progression through the G2 phase of the cell cycle. We cloned an S. pombe gene that could complement the temperature-sensitive growth of the cdc6-23 mutant. Unexpectedly, the cloned gene was allelic to pol3, which encodes the catalytic subunit of DNA polymerase δ. Integration mapping confirmed that cdc6 and pol3 are identical. The cdc6-23 mutant carries one amino acid substitution in the conserved N3 region of Pol3. Received: 17 October 1996 / Accepted: 19 November 1996     

Association between light exposure at night and manic symptoms in bipolar disorder: cross-sectional analysis of the APPLE cohort

ABSTRACT

Previous studies have found that keeping the room dark at night was associated with a decrease in manic symptoms for patients with bipolar disorder (BD). However, the association between light at night of real-life conditions and manic symptoms is unclear. We investigated the association between bedroom light exposure at night and manic symptoms in BD patients. One-hundred and eighty-four outpatients with BD participated in this cross-sectional study. The average light intensity at night during sleep was evaluated using a portable photometer for seven consecutive nights. Manic symptoms were assessed using the Young Mania Rating Scale (YMRS), and scores ≥5 were treated as a “hypomanic state.” The median (interquartile range) YMRS score was 2.0 (0–5.0), and 52 (28.2%) participants were in a hypomanic state. The prevalence of a hypomanic state was significantly higher in the participants with an average light intensity at night exposure of ≥3 lux than in those with <3 lux (36.7% versus 21.9%; P = .02). In multivariable logistic regression analysis adjusted for BD type, depressive symptoms, sleep duration, and daytime physical activity, the odds ratio (OR) for a hypomanic state was significantly higher for the participants with an average light intensity at night exposure of ≥3 lux than for those with <3 lux (OR: 2.15, 95% confidence interval: 1.09–4.22, P = .02). This association remained significant at the cutoff value of YMRS score ≥6 (OR: 2.51, 95% confidence interval: 1.15–5.46; P = .02). The findings of this study indicate bedroom light exposure at night is significantly associated with manic symptoms in BD patients. Although the results of this cross-sectional investigation do not necessarily imply causality, they may serve to inform beneficial nonpharmacological intervention and personalized treatment of BD patients.     

Regulation of retrochalcone biosynthesis: Activity changes of O-methyltransferases in the yeast extract-induced Glycyrrhiza echinata cells

Three O-methyltransferases which catalyze S-adenosyl-L-methionine (SAM)-dependent O-methylation of licodione (LMT), flavone/flavonol (FMT), and caffeic acid (CMT) were separated from the callus culture of Glycyrrhiza echinata, and characteristic differences between their pH optima and Mg²⁺ requirement for activity were demonstrated. The activity of LMT, which is involved in retrochalcone (echinatin) biosynthesis, but not of FMT or CMT, was found to be stimulated when suspension-cultured G. echinata cells were treated with yeast extract (YE), which causes rapid production of echinatin in the cells. Cycloheximide suppressed both the YE-induced echinatin formation and LMT enhancement. The results indicate a selective induction of retrochalcone pathway in Glycyrrhiza cells in response to stress.Abbreviations SAM S-adenosyl-L-methionine - LMT, SAM licodione 2-O-methyltransferase - FMT, SAM flavone/flavonol O-methyltransferase - CMT, SAM caffeate 3-O-methyltransferase - OMT O-methyltransferase - CH cycloheximide - YE yeast extract This paper is Part 47 in the series Studies on Plant Tissue Cultures. For Part 46, see Ayabe S, Iida K, Furuya T (1986) Phytochemistry: in press     

Effect of UV-B (290–320 nm) irradiation on growth and metabolism of cucumber cotyledons

Cucumber ( Cucumis sativus L. cv. Natsusairaku 3) seedlings were grown in a growth cabinet under UV-B (290–320 nm) irradiation (equivalent to the UV-B radiation normally incident at Tokyo, 36°N latitude, during clear sky conditions in mid-april on a weighted daily fluence basis) and a UV-B-free control condition. UV-B irradiation inhibited the growth of the cotyledons, i.e. the increase in area, and increase in fresh and dry weights of the cotyledons. The greatest inhibition rate was observed in the increase in area, causing a significant increase in specific leaf weight (the ratio of weight to area). UV-B irradiation had no significant effect on DNA and RNA contents in the cotyledons, but decreased protein content slightly. In contrast, the irradiation reduced the amounts of organic acids and soluble sugars, indicating that primary carbon metabolism was very sensitive to UV-B radiation. UV-B irradiation lowered the photosynthetic activity in the cotyledons without any effect on chlorophyll content and respiratory activity. These results indicate that UV-B radiation at the ambient level may act as a physiological stress in some UV-sensitive plants.     

Identification of a novel nifH-like (frxC) protein in chloroplasts of the liverwort Marchantia polymorpha

The frxC gene, one of the unidentified open reading frames present in liverwort chloroplast DNA, shows significant homology with the nifH genes coding for the Fe protein, a component of the nitrogenase complex (Ohyama et al., 1986, Nature 322: 572–574). A truncated form of the frxC gene was designed to be over-expressed in Escherichia coli and an antibody against this protein was prepared using the purified product as an antigen. This antibody reacted with a protein in the soluble fraction of liverwort chloroplasts, which had an apparent molecular weight of 31 000, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in good agreement with a putative molecular weight of 31945 deduced from the DNA sequence of the frxC gene. In a competitive inhibition experiment, the antigenicity of this protein was indicated to be similar to that of the over-expressed protein in E. coli. Therefore, we concluded that the frxC gene was expressed in liverwort chloroplasts and that its product existed in a soluble form. The molecular weight of the frxC protein was approximately 67 000, as estimated by gel filtration chromatography, indicating that the frxC protein may exist as a dimer of two identical polypeptides analogous to the Fe protein of nitrogenase. The results obtained from affinity chromatography supported the possibility that the frxC protein, which possesses a ATP-binding sequence in its N-terminal region that is conserved among various other ATP-binding proteins, has the ability to bind ATP.     

Comparison of the regional distribution of calspectin (nonerythroid spectrin or fodrin), alpha-actinin, vinculin nonerythroid protein 4.1, and calpactin in normal and avian sarcoma virus- or Rous sarcoma virus-induced transformed cells

With fluorescence and interference reflection microscopy (IRM), we compared the regional distribution of calspectin, its interacting proteins (nonerythroid protein 4.1 and calpactin), alpha-actinin, and vinculin in NRK cells and their avian sarcoma virus (ASV)- or temperature-sensitive (ts) Rous sarcoma virus (RSV)-transformed cells. The localization of these cytoskeletal proteins was determined with the specific antibodies. In NRK cells, alpha-actinin and vinculin were concentrated at adhesion plaques. By contrast, calspectin was distributed throughout the cytoplasm, but not concentrated at adhesion plaques. In ASV- and ts RSV-transformed cells, all three cytoskeletal proteins were concentrated at dot structures representing cellular feet. Nonerythroid protein 4.1 and calpactin were diffusely distributed throughout the cytoplasm of NRK cells and their transformed counterparts. In the case of calpactin, a part of this protein was excluded near regions of the terminal ends of stress fibers. These two proteins did not show the restricted location at the dot structures of transformed cells. From these findings, it is apparent that the accumulation of calspectin into dot structures is a specific event for cell transformation induced by the src protein.