Purple-fleshed sweet potato is good for health due to rich anthocyanins in tubers. Although the anthocyanin biosynthetic pathway is well understood in up-ground organs of plants, the knowledge on anthocyanin biosynthesis in underground tubers is limited. In the present study, we isolated and functionally characterized a root-preferential gene encoding dihydrokaempferol reductase (IbDHKR) from purple-fleshed sweet potato. IbDHKR showed highly similarity with the reported dihydroflavonol reductases in other plant species at the sequence levels and the NADPH-binding motif and the substrate-binding domain were also found in IbDHKR. The tissue profile showed that IbDHKR was expressed in all the tested organs, but with much higher level in tuber roots. The expression level of IbDHKR was consistent with the anthocyanin content in sweet potato organs, suggesting that tuber roots were the main organs to synthesize anthocyanins. The recombinant 44 kD IbDHKR was purified and fed by three different dihydroflavonol substrates including dihydrokaempferol (DHK), dihydroquerctin, and dihydromyrecetin. The substrate feeding assay indicated that only DHK could be accepted as substrate by IbDHKR, which was reduced to leucopelargonidin confirmed by LC-MS. Finally, IbDHKR was overexpressed in transgenic tobacco. The IbDHKR-overexpression tobacco corolla was more highly pigmented and contained higher level of anthocyanins than the wild-type tobacco corolla. In summary, IbDHKR was a root-preferential gene involved in anthocyanin biosynthesis and its encoding protein, specifically catalyzing DHK reduction to yield leucopelargonidin, was a candidate gene for engineering anthocyanin biosynthetic pathway.
Background:Familial nonmedullary thyroid carcinoma (FNMTC) is a variant of nonmedullary thyroid carcinoma(NMTC) with particular clinicopathologic features. In recent years, a number of studies have shown that FNMTC is more invasive than sporadic NMTC(SNMTC). The purpose of this study was to explore the differences in clinicopathologic features of FNMTC between different types of families and to determine in which of these families more invasive FNMTC occurred.Methods:We retrospectively reviewed all patients with thyroid carcinoma admitted to Peking Union Medical College Hospital from January 2009 to July 2013 in the database. Of all 2000 cases, 55 met the inclusive criteria for FNMTC and were studied. There are two different grouping methods. The first is that all samples were allocated to families with three or more first-degree relatives affected (FNMTC-3 group) and families with only two affected first-degree relatives (FNMTC-2 group). The second is that all patients were divided into families with three or more affected first-degree relatives over two generations (FNMTC-3-2 group) and the other families. We compared the clinicopathologic features such as sex, age, tumor size, multifocality, location, complications by thyroiditis, complications by benign thyroid nodules, surgical procedure, capsule invasion, histological type, lymph node metastases, tumor node metastasis stage, and BRAF mutation between FNMTC-2 group and FNMTC-3 group. We also made the same comparison between FNMTC-3-2 group and other families.Results:No pronounced differences in clinicopathological features were present between FNMTC-2 group and FNMTC-3 group. The proportion of FNMTC-3-2 group aged <45 years was significantly higher than that in the other families (58.8% vs. 26.3%, P = 0.021). A similar difference was found in the proportion of lymph node metastasis (64.7% vs. 34.2%, P = 0.035).Conclusions:FNMTC-3-2 is more invasive than the other families. Early screening and positive treatment for members of these families are recommended.
A macroscopic graphene is thermally annealed in oxygen gas, and Raman spectroscopy shows that the number of structural defects increases after thermal annealing. The temperature dependence of resistance is studied in macroscopic graphene with different numbers of structural defects in various gas environments. The temperature dependent slope of normalized resistance is independent of the number of structural defects and is small in the gas environment of heavier molecules. Following the temperature dependent slopes of normalized resistance, one can identify the molecule mass of the environmental gas. The temperature dependence of thermal electric power is sensitive to the quantity of the structural defects.
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