Flavonoids were found to synergize anti-malaria and anti-cancer compounds in Artemisia annua, a very important economic crop in China. In order to discover the regulation mechanism of flavonoids in Artemisia annua, the full length cDNA of flavanone 3-hydroxylase (F3H) were isolated from Artemisia annua for the first time by using RACE (rapid amplification of cDNA ends). The completed open read frame of AaF3H was 1095 bp and it encoded a 364-amino acid protein with a predicted molecular mass of 41.18 kDa and a pI of 5.67. The recombinant protein of AaF3H was expressed in E. coli BL21(DE3) as His-tagged protein, purified by Ni-NTA agrose affinity chromatography, and functionally characterized in vitro. The results showed that the His-tagged protein (AaF3H) catalyzed naringenin to dihydrokaempferol in the present of Fe(2+). The Km for naringenin was 218.03 μM. The optimum pH for AaF3H reaction was determined to be pH 8.5, and the optimum temperature was determined to be 35 °C. The AaF3H transcripts were found to be accumulated in the cultivar with higher level of flavonoids than that with lower level of flavonoids, which implied that AaF3H was a potential target for regulation of flavonoids biosynthesis in Artemisia annua through metabolic engineering.

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MAX phase containing Ti-Al-(C, N) composite coatings is promising in marine engineering due to the improved tribocorrosion performance of titanium alloys. Therefore, novel Ti-Al-(C, N) composite coatings were prepared in this study using laser cladding on TC4 substrate. Electrochemical performances of as-obtained composite coatings were then analyzed under static and dynamic conditions in an artificial seawater environment, and their tribocorrosion behaviors and corrosion–wear synergism mechanism were examined by a tribocorrosion test system. The results showed that the existence of self-lubricating phases Ti2AlC and Ti2AlN in composite coatings and the corrosion products with a certain lubrication effect generated during the friction process kept the average friction coefficient at a low level. With the increase of load, the mechanical failure of the passive film in the friction process was enhanced, the adsorption of corrosive medium on the surface of the passive film led to its active dissolution, and the wear volume increased from 1.45 × 10−2 to 3.24 × 10−2 mm3. The corrosion of composite coatings in artificial seawater was not extensive, and volume loss caused by tribocorrosion was mainly determined by wear behavior. In sumary, the coatings exhibited good bearing capacity in the marine environment, thereby showing broad prospects for marine equipment applications.

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