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duction. Later the process was optimized and refined by the authors (Zhao et al.
2001b
), after 10 days of
C. roseus
cells in shake flasks and in bioreactor they re-
ported 25 mg/l, 32 mg/l and 22 mg/l catharanthine yields in 500 ml flasks, 1,000 ml
flasks and in 20 l airlift bioreactor, respectively. The defense responses, such as lipid
peroxidation was believed to be stimulated by the combination of malate and algi-
nate treatment in all
C. roseus
culture processes which further mediate the catharan-
thine production via the jasmonate pathway. El-Sayed and Verpoorte (
2002
) tested
2, 4-D and abscisic acid (phytohormones), salicylic acid (SA) and MJ on growth
and accumulation of secondary metabolites in
C. roseus
cell suspension culture
upon feeding with the precursors loganin and tryptamine. Among the tested treat-
ments only MJ enhanced the accumulation of alkaloids whereas due to addition of
abscisic acid catabolism of strictosidine was delayed.
Zheng and Wu (
2004
) treated the
C. roseus
cell with different Cadmium (Cd)
concentration (0.05 to 0.4mM) and ajmalicine yield was monitored. They reported
that due to Cd treatment a higher yield of ajmalicine was recorded because of the in-
creased level of tryptophan decarboxylase (Tdc) transcript, the cellular tryptamine
concentration, and ajmalicine excretion. The effect of different elements namely Co,
Zn, Ni, Mn, Cr, W, Cu, B, V, Fe, and Mo and various hormones including natural
and synthetic auxins, cytokinins, and gibberellin on the production and accumula-
tion of indole alkaloids in
C. roseus
was investigated (Lovkova et al.
2005
) studied.
These compounds modified different phases in the biosynthesis of catharanthine
and vindoline and up to a certain extent a feasible mechanism of the effect of Zn and
auxin on this process were simplified. In
C. roseus
cell suspension cultures indole
alkaloid production through a protein kinase-dependent signal pathway was stimu-
lated using nitric oxide (Xu and Dong
2005
) whereas CaCl
2
enhanced MJ-induced
ajmalicine production in
C. roseus
(Lee-parson and Ertürk
2005
). About 160 % in-
crease in ajmalicine production was noted in
C. roseus
cultures and the synthesis
depends on intracellular Ca
2
+
concentration. When Ca
2
+
influx was increased after
a certain level by the addition of extracellular Ca
2
+
, ajmalicine production was de-
clined, similarly a decrease in the accumulation of alkaloids was noted down when
Ca
2
+
influx was dropped off.
For the production of ajmalicine in
C. roseus
cultures different strategies of op-
timizing gas compositions were used (Lee-Parsons
2007
). Guo et al. (
2007
) con-
ducted an experiment to study the effect of various temperatures on variation of
alkaloid metabolism in
C. roseus
seedlings. The authors observed that with relation
to the treatment time, at high temperature biosynthesis of different alkaloids were
elevated in
C. roseus
seedlings. In
C. roseus
cell suspension culture a low dose of
UV-B irradiation was applied (Ramani and Jayabaskaran
2007
), which stimulated
the transcription of genes encoding tryptophan decarboxylase (
Tdc)
and strictosi-
dine synthetase
(Str)
and induced enhanced amount of catharanthine. In another ex-
periment Ramani and Chelliah (
2008
) evaluated the influence of UV-B treatment on
cell suspension culture of
C. roseus
in different growth phase. The results suggested
that in stationary phase cultures the response to UV-B irradiation was more than the
late exponential phase. There was a 3 and 12-fold enhancement in catharanthine and
vindoline respectively. An efficient and promising protocol for achievement and
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