BackgroundFlavonoid 3′,5′-hydroxylase (F3′5′H), an important branch point enzyme in tea plant flavan-3-ol synthesis, belongs to the CYP75A subfamily and catalyzes the conversion of flavones, flavanones, dihydroflavonols and flavonols into 3′,4′,5′-hydroxylated derivatives. However, whether B-ring hydroxylation occurs at the level of flavanones and/or dihydroflavonols, in vivo remains unknown.ResultsThe Camellia sinensis F3′5′H (CsF3′5′H) gene was isolated from tea cDNA library. Expression pattern analysis revealed that CsF3′5′H expression was tissue specific, very high in the buds and extremely low in the roots. CsF3′5′H expression was enhanced by light and sucrose. Over-expression of CsF3′5′H produced new-delphinidin derivatives, and increased the cyanidin derivative content of corollas of transgenic tobacco plants, resulting in the deeper transgenic plant flower color. Heterologous expressions of CsF3′5′H in yeast were carried out to demonstrate the function of CsF3′5′H enzyme in vitro. Heterologous expression of the modified CsF3′5′H (CsF3′5′H gene fused with Vitis vinifera signal peptide, FSI) revealed that 4′-hydroxylated flavanone (naringenin, N) is the optimum substrate for CsF3′5′H, and was efficiently converted into both 3′4′- and 3′4′5′-forms. The ratio of 3′4′5′- to 3′4′-hydroxylated products in FSI transgenic cells was significantly higher than VvF3′5′H cells.ConclusionsCsF3′5′H is a key controller of tri-hydroxyl flavan-3-ol synthesis in tea plants, which can effectively convert 4′-hydroxylated flavanone into 3′4′5′- and/or 3′4′-hydroxylated products. These findings provide animportant basis for further studies of flavonoid biosynthesis in tea plants. Such studies would help accelerate flavonoid metabolic engineering in order to increase B-ring tri-hydroxyl product yields.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0347-7) contains supplementary material, which is available to authorized users.

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There were several high concentrations of flavonoid components in tea leaves that present health benefits. A novel purple-leaf tea variety, ‘Mooma1’, was obtained from the natural hybrid population of Longjing 43 variety. The buds and young leaves of ‘Mooma1’ were displayed in bright red. HPLC and LC-MS analysis showed that anthocyanins and O-Glycosylated flavonols were remarkably accumulated in the leaves of ‘Mooma1’, while the total amount of catechins in purple-leaf leaves was slightly decreased compared with the control. A R2R3-MYB transcription factor (CsMYB6A) and a novel UGT gene (CsUGT72AM1), that were highly expressed in purple leaf were isolated and identified by transcriptome sequencing. The over-expression of transgenic tobacco confirmed that CsMYB6A can activate the expression of flavonoid-related structural genes, especially CHS and 3GT, controlling the accumulation of anthocyanins in the leaf of transgenic tobacco. Enzymatic assays in vitro confirmed that CsUGT72AM1 has catalytic activity as a flavonol 3-O-glucosyltransferase, and displayed broad substrate specificity. The results were useful for further elucidating the molecular mechanisms of the flavonoid metabolic fluxes in the tea plant.

In this work, a secure wireless sensor network (WSN) for the surveillance, monitoring and protection of critical infrastructures was developed. To guarantee the security of the system, the main focus was the implementation of a unique security concept, which includes both security on the communication level, as well as mechanisms that ensure the functional safety during its operation. While there are many theoretical approaches in various subdomains of WSNs-like network structures, communication protocols and security concepts-the construction, implementation and real-life application of these devices is still rare. This work deals with these aforementioned aspects, including all phases from concept-generation to operation of a secure wireless sensor network. While the key focus of this paper lies on the security and safety features of the WSN, the detection, localization and J. Sens. Actuator Netw. 2015, 4 337 classification capabilities resulting from the interaction of the nodes' different sensor types are also described.

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An aluminum/High-Density Polyethylene (HDPE) functionally graded material (FGM) has been fabricated as an essential component of a multifunctional building envelope for high performance of energy efficiency and sustainability. The mass production of the FGM was realized by using coarse Aluminum (Al) particles and fine HDPE powder through a vibration-sedimentation process. The gradation of the FGM across its thickness direction was analyzed by developing a modified Rice method, from which five different uniform Al-HDPE samples were made to characterize the material properties of the five sub-layers of the FGM. The mechanical and thermal physical properties of the FGM such as Young's modulus, Poisson ratio, thermal expansion coefficients and thermal conductivities were obtained by various experimental characterizations. A prototype FGM panel with water tubes embedded was fabricated by the vibration and sedimentation combined approach and the thermal efficiency of the FGM panel was evaluated. Under an irradiation level of 620 w/m 2 and a water flowing rate of 60ml/min, a 22.3 o C water temperature increase and an average 18.7 o C surface temperature decrease of the FGM panel were achieved, which demonstrates that significant PV conversation efficiency improvement can be realized for both electricity generation and heat collection by the presented FGM panel. The presented fabrication procedures and the associated experimental characterization methods and results can serve as a baseline for quality control of the manufacture of the green energy building envelope materials.

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