No abstract

Homozygous lines of barley overexpressing a wheat thioredoxin h transgene (up to 30-fold) were generated earlier by using a B1-hordein promoter with a signal peptide sequence for targeting to the protein body and found to be enriched in starch debranching enzyme (pullulanase). Here, we describe the effect of biochemically active, overexpressed thioredoxin h on germination and the onset of ␣-amylase activity. Relative to null segregant controls lacking the transgene, homozygotes overexpressing thioredoxin h effected (i) an acceleration in the rate of germination and appearance of ␣-amylase activity with a 1.6-to 2.8-fold increase in gibberellin A1 (GA1) content; (ii) a similar acceleration in the appearance of the ␣-amylase activity in deembryonated transgenic grain incubated with gibberellic acid; (iii) a 35% increase in the ratio of relative reduction (abundance of SH) of the propanol soluble proteins (hordein I fraction); and (iv) an increase in extractable and soluble protein of 5-12% and 11-35%, respectively. Thioredoxin h, which was highly reduced in the dry grain, was degraded in both the null segregant and homozygote after imbibition. The increase in ␣-amylase activity and protein reduction status was accompanied by a shift in the distribution of protein from the insoluble to the soluble fraction. The results provide evidence that thioredoxin h of the starchy endosperm communicates with adjoining tissues, thereby regulating their activities, notably by accelerating germination of the embryo and the appearance of ␣-amylase released by the aleurone.

Background: Our aim was to investigate the distribution pattern of cerebral artery calcification and its association with white matter hyperintensities (WMH). Methods: We identified 159 consecutive patients with acute ischemic stroke. Calcifications of cerebral arteries and WMH were graded. Results: Cerebral artery calcification was found in 137 patients (86.2%). The intracranial internal carotid artery (I-ICA) was the most frequently affected artery with calcification (76.7%) and moderate-to-severe calcification (38.1%). Spearman’s rank test revealed that the grade of I-ICA calcification was correlated with those of periventricular WMH (r = 0.417, p < 0.001) and deep WMH (r = 0.388, p < 0.001). The adjusted ORs of I-ICA were 2.62 (p <0.05) for periventricular WMH and 3.25 (p <0.05) for deep WMH. Conclusions: Cerebral artery calcification is common in patients with ischemic stroke. I-ICA is the most frequently and most severely affected cerebral artery and its calcification is associated with WMH.

Work with cereals (barley and wheat) and a legume (Medicago truncatula) has established thioredoxin h (Trx h) as a central regulatory protein of seeds. Trx h acts by reducing disulfide (S-S) groups of diverse seed proteins (storage proteins, enzymes, and enzyme inhibitors), thereby facilitating germination. Early in vitro protein studies were complemented with experiments in which barley seeds with Trx h overexpressed in the endosperm showed accelerated germination and early or enhanced expression of associated enzymes (alpha-amylase and pullulanase). The current study extends the transgenic work to wheat. Two approaches were followed to alter the expression of Trx h genes in the endosperm: (1) a hordein promoter and its protein body targeting sequence led to overexpression of Trx h5, and (2) an antisense construct of Trx h9 resulted in cytosolic underexpression of that gene (Arabidopsis designation). Underexpression of Trx h9 led to effects opposite to those observed for overexpression Trx h5 in barley-retardation of germination and delayed or reduced expression of associated enzymes. Similar enzyme changes were observed in developing seeds. The wheat lines with underexpressed Trx showed delayed preharvest sprouting when grown in the greenhouse or field without a decrease in final yield. Wheat with overexpressed Trx h5 showed changes commensurate with earlier in vitro work: increased solubility of disulfide proteins and lower allergenicity of the gliadin fraction. The results are further evidence that the level of Trx h in cereal endosperm determines fundamental properties as well as potential applications of the seed.