Whole fungal elicitors boost paclitaxel biosynthesis induction in Corylus avellana cell culture.

Paclitaxel is an effective natural-source chemotherapeutic agent commonly applied to treat a vast range of cancers. In vitro Corylus avellana culture has been reported as a promising and inexpensive system for paclitaxel production. Fungal elicitors have been made known as the most efficient strategy for the biosynthesis induction of secondary metabolites in plant in vitro culture. In this research, C. avellana cell suspension culture (CSC) was exposed to cell extract (CE) and culture filtrate (CF) derived from Camarosporomyces flavigenus, either individually or combined treatment, in mid and late log phase. There is no report on the use of whole fungal elicitors (the combined treatment of CE and CF) for the elicitation of secondary metabolite biosynthesis in plant in vitro culture. The combined treatment of CE and CF significantly led to more paclitaxel biosynthesis and secretion than the individual use of them. Also, multivariate statistical approaches including stepwise regression (SR), ordinary least squares regression (OLSR), principal component regression (PCR) and partial least squares regression (PLSR) were used to model and predict paclitaxel biosynthesis and secretion. Based on value account for (VAF), root mean square error (RMSE), coefficient of determination (R2), mean absolute percentage error (MAPE) and relative percent difference (RPD) can be concluded that mentioned regression models effectively worked only for modeling and predicting extracellular paclitaxel portion in C. avellana cell culture.

Development of a hazel cell culture-based paclitaxel and baccatin III production process on a benchtop scale.

The growing demand for the antitumorous agent paclitaxel and the difficulty in increasing its production by genetic engineering has prompted a search for new sources of taxanes. It has been reported that taxanes can be extracted from the angiosperm Corylus avellana L. Our aim was to improve taxane production by scaling up the process from mL-level to benchtop bioreactors, optimizing culture conditions and comparing the effect of two elicitors, 1 µM coronatine (Cor) and 100 µM methyl jasmonate (MeJA). Orbitally shaken flask cultures achieved a maximum fresh cell weight of 11.54 gDCW/L under control conditions, and MeJA- and Cor-treatment produced a statistically significant reduction in growth to 4.28 gDCW/L and 5.69 gDCW/L, while increasing the taxane content 3- and 27-fold, respectively. The enhancing effect of these elicitors on taxane production, despite affecting growth, was confirmed in orbitally shaken TubeSpin Bioreactors 50, where the highest taxane content (8583.3 µg/L) was obtained when 1µM Cor was used and elicitation took place at a packed cell volume of 50%. Two benchtop stirred bioreactors, BIOSTAT B plus and UniVessel SU, were compared, the latter providing a higher biomass of C. avellana cell suspension cultures. Transferring the established optimum culture conditions for taxane production to the UniVessel SU resulted in a total taxane content of 6246.1 µg/L, a 10-fold increase compared with shake flask experiments.

Effect of phenylalanine on Taxol production and antioxidant activity of extracts of suspension-cultured hazel (Corylus avellana L.) cells.

Taxol is produced by a few microorganisms and plants such as yew (Taxus sp.). Recent researches have shown that hazel (Corylus avellana L.) is also able to produce Taxol. In the present study, effects of different concentrations of phenylalanine (Phe) on the production of Taxol, antioxidant activity, and cytotoxic effects of extracts of suspension-cultured hazel cells were investigated. The cells were treated with different concentrations of Phe on day 7 of subculture and were harvested on day 14. The results showed that the amounts of Taxol and antioxidant activity were increased by increasing the phenylalanine supply. Interestingly, the cytotoxic effects of hazel cell extract were even stronger than that of pure Taxol (standard), suggesting hazel cell extract as a novel and suitable probe for treating human cancer. Application of phenylalanine to hazel cells exaggerates their effects.

Mycorrhization of Quercus robur L., Quercus cerris L. and Corylus avellana L. seedlings with Tuber macrosporum Vittad.

Tuber macrosporum Vittad. is not a common truffle species, but with remarkable organoleptic qualities and much economic interest. After the addition of truffle spore slurry, 30 seedlings of Quercus robur L., Quercus cerris L. and Corylus avellana L. were grown inside a greenhouse for 11 months before evaluation of the mycorrhizal level. Two different potting mixes were used: a natural soil-based potting mix for Q. robur, Q. cerris and C. avellana and a peat-based potting mix for Q. robur. Quercus robur planted in soil potting mix was the most receptive towards the truffle spore inoculum, with a level of formation of T. macrosporum ectomycorrhizas (ECMs) of approximately 14 %, ranging from a minimum of ∼4 % to a maximum of ∼44 % in different seedlings. No T. macrosporum ECMs developed on Q. cerris (soil potting mix) or on Q. robur (peat potting mix), whereas a low percentage of ECMs was detected on only three C. avellana (soil potting mix) seedlings. The fungus Sphaerosporella brunnea (Alb. & Schwein.) Svrcek & Kubicka was also detected as a contaminant on almost half the truffle-inoculated seedlings. A new detailed description of the morphological and anatomical characteristics of T. macrosporum ECMs and their DNA-based verification with species-specific markers were also reported.