Expression and characterization of protein disulfide isomerase family proteins in bread wheat.

BACKGROUND: The major wheat seed proteins are storage proteins that are synthesized in the rough endoplasmic reticulum (ER) of starchy endosperm cells. Many of these proteins have intra- and intermolecular disulfide bonds. In eukaryotes, the formation of most intramolecular disulfide bonds in the ER is thought to be catalyzed by protein disulfide isomerase (PDI) family proteins. The cDNAs that encode eight groups of bread wheat (Triticum aestivum L.) PDI family proteins have been cloned, and their expression levels in developing wheat grains have been determined. The purpose of the present study was to characterize the enzymatic properties of the wheat PDI family proteins and clarify their expression patterns in wheat caryopses. RESULTS: PDI family cDNAs, which are categorized into group I (TaPDIL1Aα, TaPDIL1Aß, TaPDIL1Aγ, TaPDIL1Aδ, and TaPDIL1B), group II (TaPDIL2), group III (TaPDIL3A), group IV (TaPDIL4D), and group V (TaPDIL5A), were cloned. The expression levels of recombinant TaPDIL1Aα, TaPDIL1B, TaPDIL2, TaPDIL3A, TaPDIL4D, and TaPDIL5A in Escherichia coli were established from the cloned cDNAs. All recombinant proteins were expressed in soluble forms and purified. Aside from TaPDIL3A, the recombinant proteins exhibited oxidative refolding activity on reduced and denatured ribonuclease A. Five groups of PDI family proteins were distributed throughout wheat caryopses, and expression levels of these proteins were higher during grain filling than in the late stage of maturing. Localization of these proteins in the ER was confirmed by fluorescent immunostaining of the immature caryopses. In mature grains, the five groups of PDI family proteins remained in the aleurone cells and the protein matrix of the starchy endosperm. CONCLUSIONS: High expression of PDI family proteins during grain filling in the starchy endosperm suggest that these proteins play an important role in forming intramolecular disulfide bonds in seed storage proteins. In addition, these PDI family proteins that remain in the aleurone layers of mature grains likely assist in folding newly synthesized hydrolytic enzymes during germination.

[Electroencephalographic examination of the cerebral activity of elderly people living in a nursing home after postural change from supine to sitting positions].

AIM: We investigated the cerebral activity of elderly persons living in a nursing home in the sitting position by analyzing the electroencephalography findings of postural changes in the supine and sitting positions. METHODS: This study was approved by the Health Ethics Committee of Osaka University. The subjects were 17 elderly people (4 men and 13 women, average age 85.35 ± 8.26 years) living in a nursing home. Electroencephalograms were obtained in 8 cerebral regions (the left front-polar (Fp(1)); right front-polar (Fp(2)); left frontal (F(3)); right frontal (F(4)); left central (C(3)); right central (C(4)); left occipital (O(1)) and right occipital (O(2))) while subjects sat in a head-up position in bed, or in a chair or wheelchair. Measurement was obtained over 5-minute supine, 15-minute sitting, and 5-minute conversation periods. We performed the fast Fourier transform on measured electroencephalograms to calculate the average power values of alpha band components (8-13 Hz) and beta band components (13-30 Hz) for each cerebral section. RESULTS: Compared with the supine position, the sitting position in bed did not show a significant increase in power values, whereas the sitting position in a chair showed significant increases in power values in all regions. Most of the time, the findings of patients sitting position in a chair showed significantly higher power values than those of patients sitting in bed in all regions. CONCLUSIONS: During the 20 minutes after postural change from the supine to sitting positions, the cerebral activity of subjects sitting in a chair was higher than that of subjects sitting in bed.