Extraction and characterisation of pigment from Yanzhiguo [Prunus napaulensis (Ser.) Steud.].

Yanzhiguo [Prunus napaulensis (Ser.) Steud] belongs to Rosaceae family and is consumed as wild fruit, pulp and juice. However, its potential for extracting natural pigment has not yet been explored. Herein, the components in the fresh Yanzhiguo pulp were preliminarily analyzed by liquid chromatography coupled to mass spectrometry. And, the optimal pre-treatment conditions were established for further extraction of Yanzhiguo pigment based on the a* value. Then, by combining the data from single-factor experiments and response surface methodology, the optimal extraction process was established as: 35% EtOH, a liquid-solid ratio of 200:1 mL g-1, an extraction time of 65 min, and an extraction temperature of 100 °C. Moreover, it was found that the a* value and yield had high fitness except when extracted into ethanol (EtOH) with different concentrations. Meanwhile, our result demonstrated Yanzhiguo pigment had high stability in general environments with carmine (a synthetic pigment) as control, except for extreme environments such as direct (hot) sunlight, high temperature (75 °C) and strong alkaline (pH ≥ 11). Also, Yanzhiguo pigment exhibited good antioxidant activity. Our results contribute to more information on Yanzhiguo pigment and promote its application by providing efficient extraction technology.

Expression profiling of a novel calcium-dependent protein kinase gene, LeCPK2, from tomato (Solanum lycopersicum) under heat and pathogen-related hormones.

A full-length cDNA LeCPK2 (GenBank GQ205414) from tomato (Solanum lycopersicum) encoding a calcium-dependent protein kinase (CDPK) was cloned by in silico cloning using NtCPK5 (AY971376) as a virtual probe. The deduced amino acid sequence of LeCPK2 contained the kinase, autoinhibitory, and calmodulin-like domains typical of CDPKs. Expression profiling indicated that LeCPK2 expressed predominantly in flowers and responded divergently to heat and cold stress, in which obvious mRNA accumulation was detected at 4 h under 42 degrees C stress, but no change in LeCPK2 mRNA levels was observed in 6 h at 4 degrees C. Mechanical wounding and phytohormones including ethylene, methyl jasmonate, and salicylic acid were also observed to arouse the expression of LeCPK2 in a similar pattern. mRNA accumulation was enhanced at 30 min and reached a maximum at 3 h, followed by a decrease to the normal level. All the results suggest that LeCPK2 is a novel versatile isoform of tomato CDPKs.