Advances in Biotechnological Production and Metabolic Regulation of Astragalus membranaceus

Legume medicinal plants Astragalus membranaceus are widely used in the world and have very important economic value, ecological value, medicinal value, and ornamental value. The bioengineering technology of medicinal plants is used in the protection of endangered species, the rapid propagation of important resources, detoxification, and the improvement of degraded germplasm. Using bioengineering technology can effectively increase the content of secondary metabolites in A. membranaceus and improve the probability of solving the problem of medicinal plant resource shortage. In this review, we focused on biotechnological research into A. membranaceus, such as the latest advances in tissue culture, including callus, adventitious roots, hairy roots, suspension cells, etc., the metabolic regulation of chemical compounds in A. membranaceus, and the research progress on the synthetic biology of astragalosides, including the biosynthesis pathway of astragalosides, microbial transformation of astragalosides, and metabolic engineering of astragalosides. The review also looks forward to the new development trend of medicinal plant biotechnology, hoping to provide a broader development prospect for the in-depth study of medicinal plants.

Application of Data Modeling, Instrument Engineering and Nanomaterials in Selected Medid the Scientific Recinal Plant Tissue Culture

At present, most precious compounds are still obtained by plant cultivation such as ginsenosides, glycyrrhizic acid, and paclitaxel, which cannot be easily obtained by artificial synthesis. Plant tissue culture technology is the most commonly used biotechnology tool, which can be used for a variety of studies such as the production of natural compounds, functional gene research, plant micropropagation, plant breeding, and crop improvement. Tissue culture material is a basic and important part of this issue. The formation of different plant tissues and natural products is affected by growth conditions and endogenous substances. The accumulation of secondary metabolites are affected by plant tissue type, culture method, and environmental stress. Multi-domain technologies are developing rapidly, and they have made outstanding contributions to the application of plant tissue culture. The modes of action have their own characteristics, covering the whole process of plant tissue from the induction, culture, and production of natural secondary metabolites. This paper reviews the induction mechanism of different plant tissues and the application of multi-domain technologies such as artificial intelligence, biosensors, bioreactors, multi-omics monitoring, and nanomaterials in plant tissue culture and the production of secondary metabolites. This will help to improve the tissue culture technology of medicinal plants and increase the availability and the yield of natural metabolites.

Attributes of Polygonum multiflorum to transfigure red biotechnology

A vast array of plant-based compounds has enriched red biotechnology to serve the human health and food. A peculiar medicinal plant which was an element of traditional Chinese medicine for centuries as a liver and kidney tonic, for life longevity and hair blackening, is Polygonum multiflorum Thunb. (PM) which is popularly known as "He shou wu" or "Fo-ti" and is rich in chemical components like stilbenes, quinones, and flavonoids which have been used as anti-aging, anti-alopecia, anti-cancer, anti-oxidative, anti-bacterial, anti-hyperlipidemia, anti-atherosclerosis, and immunomodulating and hepatoprotective agents in the modern medicine. The health benefits from PM are attained since long through commercial products such as PM root powder, extract, capsules, tincture, shampoo, and body sprays in the market. Currently, the production of these pharmaceuticals and functional foods possessing stilbenes, quinones, and flavonoids is through cell and organ cultures to meet the commercial demand. However, hepatotoxic effects of PM-based products are the stumbling blocks for its long-term usage. The current review encompasses a comprehensive account of bioactive compounds of PM roots, their biological activities as well as efficacy and toxicity issues of PM ingredients and future perspectives.

The safety assessment of food ingredients derived from plant cell, tissue and organ cultures: a review

Plant cell, tissue and organ cultures (PCTOC) have become an increasingly attractive alternative for the production of various high molecular weight molecules which are used as flavourings, fragrances, colouring agents and food additives. Although PCTOC products are cultivated in vitro in a contamination free environment, the raw material produced from PCTOC may contain many components apart from the target compound. In some cases, PCTOC raw materials may also carry toxins, which may be naturally occurring or accumulated during the culture process. Assessment of the safety of PCTOC products is, therefore, a priority of the biotech industries involved in their production. The safety assessment involves the evaluation of starting material, production process and the end product. Before commercialisation, PCTOC products should be evaluated for their chemical and biological properties, as well as for their toxicity. In this review, measures and general criteria for biosafety evaluation of PCTOC products are addressed and thoroughly discussed.

A strategy for enrichment of the bioactive sphingoid base-1-phosphates produced by Hypericum perforatum L. in a balloon type airlift reactor

An efficient enrichment method using immobilized metal affinity chromatography (IMAC) was developed for selective extraction of bioactive sphingoid base-1-phosphates (SB1Ps) from adventitious roots of Hypericum perforatum cultured in bioreactor. The phosphate-selective IMAC enrichment coupled with LC-MS/MS enabled sensitive analysis of low-abundance SB1Ps present in the root biomass, which would not be feasible otherwise due to severe interferences from complex biological matrices. The time-dependent growth rate and production of SB1Ps from adventitious roots were investigated. The level of phytosphingosine-1-phosphate, which was found to be the major SB1Ps, reached a maximum amount of 635.6pmolpergram of dry weight after 3weeks of culture and decreased between 3 and 5weeks of culture subsequently. On the other hand, sphingosine-1-phosphate and sphinganine-1-phosphate were present at levels of 18.91 and 73.15pmolpergram of dry weight, respectively, after a week of culture and their level decreased thereafter.

Production of adventitious root biomass and secondary metabolites of Hypericum perforatum L. in a balloon type airlift reactor

The effects of inoculum density, aeration volume and culture period on accumulation of biomass and secondary metabolites in adventitious roots of Hypericum perforatum in balloon type airlift bioreactors (3 l capacity) were investigated. The greatest increment of biomass as well as metabolite content occurred at an inoculum density of 3 g l(-1) and an aeration volume of 0.1 vvm. After 6 weeks of culture, an approximately 50-fold increase in biomass was recorded containing 60.11 mg g(-1) dry weight (DW) of phenolics, 42.7 mg g(-1) DW of flavonoids and 0.80 mg g(-1) DW of chlorogenic acid. Liquid chromatography-mass spectroscopy/mass spectroscopy demonstrated that the presence of quercetin and hyperoside in adventitious roots at a level of 1.33 and 14.01 μg g(-1) DW, respectively after 6 weeks of culture. The results suggest scale-up of adventitious root culture of H. perforatum for the production of chlorogenic acid, quercetin and hyperoside is feasible.

Influence of inoculum density and aeration volume on biomass and bioactive compound production in bulb-type bubble bioreactor cultures of Eleutherococcus koreanum Nakai

This study deals with the effects of initial inoculum density and aeration volume on biomass and bioactive compound production in adventitious roots of Eleutherococcus koreanum Nakai in bulb-type bubble bioreactors (3-L capacity). While the fresh and dry weights of the roots increased with increasing inoculum density, the highest percentage dry weight and accumulation of total target compounds (eleutheroside B and E, chlorogenic acid, total phenolics, and flavonoids) were noted at an inoculum density of 5.0 g L(-1). Poor aeration volume (0.05 vvm) stunted root growth, and high aeration volume (0.4 vvm) caused physiological disorders. Moreover, an inoculum density of 5.0 g L(-1) and an aeration volume of 0.1 vvm resulted in the highest concentration of total target compounds and least root death. Such optimization of culture conditions will be beneficial for the large-scale production of E. koreanum biomass and bioactive compounds.

Bioprocess and bioreactor: next generation technology for production of potential plant-based antidiabetic and antioxidant molecules

Globally, diabetes and obesity are two of the most common metabolic diseases of the 21(st) century. Increasingly, not only adults but children and adolescents are being affected. New approaches are needed to prevent and treat these disorders and to reduce the impact of associated disease-related complications. Industrial-scale production using plant-root cultures can produce quantities and quality of inexpensive bioactive small molecules with nutraceutical and pharmaceutical properties. Using this approach, and targeting these diseases, a next generation approach to tackling this emerging global health crisis may be developed. Adventitious roots cultured in bioreactors under controlled and reproducible conditions have been shown effective for production of natural products. The liquid-phase airlift bioreactor in particular has been used successfully for culturing roots on an industrial-scale and thus may provide an economical production platform for expressing promising plant-based antidiabetic and antioxidant molecules. This review focuses on a next-generation, scalable, bioprocessing approach for adventitious and hairy root cultures that are a pesticide-free, seasonally-independent, plant-based source of three molecules that have shown promise for the therapeutic management of diabetes and obesity: corosolic acid, resveratrol and ginsenosides.

Medium salt strength induced changes in growth, physiology and secondary metabolite content in adventitious roots of Morinda citrifolia: the role of antioxidant enzymes and phenylalanine ammonia lyase

In an attempt to improve growth and secondary metabolite production, and to understand the possible mechanism involved in relation to the changes in physiology and activities of antioxidant enzymes, we cultured Morinda citrifolia adventitious roots in different strength (0.25, 0.50, 0.75, 1.0, 1.5 and 2.0) of Murashige and Skoog (MS) medium supplemented with 5 mg l(-1) indole butyric acid and 30 g l(-1) sucrose. Quarter-strength MS medium was proven suitable for the production of both root biomass and secondary metabolites [anthraquinone (AQ), phenolics and flavonoids]. With the increasing salt strength, root growth and AQ accumulation decreased significantly. Higher (1.5 and 2 MS) salt strength provoked osmotic stress resulted in more than twofold free proline accumulation than lower salt strength treated roots and induced free radical scavenging activity. Phenylalanine ammonia lyase activity showed a positive correlation in relation to salt strength that leads to an increase in phenol biosynthesis in expense of AQ formation. The elevated catalase (CAT), guaiacol peroxidase (G-POD) and superoxide dismutase activities and decreased ascorbate peroxidase (APX) activities were observed in roots treated with 2.0 MS. On the other hand, APX activity was strongly activated along with considerable increase in CAT activity at 0.25 MS treated culture. However, the joint functions of CAT, G-POD and APX at 0.25 MS treated cultures were efficient to eliminate the potential danger of hydrogen peroxide (H(2)O(2)) as evidenced from low H(2)O(2) accumulation and low level of lipid peroxidation.

Production of adventitious roots and secondary metabolites by Hypericum perforatum L. in a bioreactor

We investigated the effects of different concentrations of auxin and auxin/cytokinin combinations, inoculum sizes and Murashige and Skoog (MS) medium dilutions on biomass and accumulation of total phenols and flavonoids in adventitious roots of Hypericum perforatum. The optimized conditions for the shake flask culture growth and secondary metabolites production were 0.1mg/l kinetin with 1mg/l indole-3-butyric acid (IBA), an inoculum density of 6g/l fresh weight (FW) and 1/2MS in the 5-week old cultures. By inoculating 6g/l of adventitious roots into a 3-l balloon type bubble bioreactor (BTBB) containing l/2 MS medium supplemented with 0.1mg/l kinetin with 1mg/l IBA, 104.2g/l adventitious roots were harvested containing 56.47+/-0.22 mg/g dry weight (DW) total phenolics, 35.01+/-1.26 mg/g DW flavonoids, 0.97+/-0.06 mg/g DW chlorogenic acid and 1.389+/-0.80 mg/g DW hypericin. The results of our study contribute to optimization and development of bioreactor technology for adventitious root cultures of H. perforatum for the production of hypericin.

Cryopreservation of Ginkgo biloba cell culture: effect of pretreatment with sucrose and ABA

The report describes the impact of preculture with sucrose and sucrose + ABA on desiccation and cryopreservation tolerance of cell cultures of Ginkgo biloba L., an important landscape and medicinal tree. Callus clumps were incubated on MS medium supplemented with high sucrose concentrations (up to 24 percent, w/v), employed alone or with ABA (2-10 mg per L) for various durations followed by desiccation for 0-240 min and cryopreservation. The beneficial effect of preculture on regrowth after desiccation without cryopreservation was only observed for the cells with water content of 20 percent FW and was not influenced by presence of ABA. However, preculture of calli in presence of ABA resulted in a lower desiccation rate as compared with untreated controls and calli pretreated with sucrose alone. In calli precultured with sucrose alone, post-thaw regrowth was occasional regardless of the sugar concentration in the medium, while pretreatment of calli with ABA and sucrose ensured stable regrowth after cryopreservation. The highest post-thaw regrowth of 54 percent was achieved for calli precultured on medium supplemented with 10 percent (w/v) sucrose and 2 mg per L ABA for 21 days followed by desiccation for 150 min. The different effects of preculture treatments on post-thaw regrowth were associated with significant changes in content and in composition of endogenous soluble sugars in calli. Sucrose and glucose accumulated preferentially in ABA-precultured calli, while the fructose content was higher in calli precultured in absence of ABA. The possible role of preculture on desiccation and cryopreservation tolerance of G. biloba cell cultures is discussed.

Nitric oxide retards xanthine oxidase-mediated superoxide anion generation in Phalaenopsis flower: an implication of NO in the senescence and oxidative stress regulation

Senescence is a developmentally regulated and highly ordered sequence of events. Senescence leads to abscission of plant organs and eventually leads to death of a plant or part of it. Present study revealed that Phalaenopsis flower undergo senescence due to over activation of O(2) (.-)generating xanthine oxidase (XO), which consequently increases the concentrations of O(2) (.-) leading to enhanced oxidative damage and disturbed cellular redox environment as indicated by increased lipid peroxidation and DHA/AsA + DHA ratio, respectively. While activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and non-specific peroxidase (POD) were enhanced in sepals and petals of old flower, activities of catalase (CAT) and glutathione reductase (GR) were decreased. Exogenous application of nitric oxide (NO) retarded H(2)O(2)-induced senescence of Phalaenopsis flower by downregulating activity of XO and concentrations of O(2) (.-), H(2)O(2) and malondialdehyde (MDA, an index of lipid peroxidation). Exogenous application of NO also downregulated SOD activity and upregulated antioxidant enzymes involved in the detoxification of H(2)O(2) (CAT and APX), and in the regulation of redox couples viz, monodehydroascorbate reductase (MDHAR) and GR, together with the modulation in non-protein thiol status and DHA/AsA + DHA ratio.

Improved production of ginsenosides in suspension cultures of ginseng by medium replenishment strategy

The objective of this study was to improve the accumulation of ginsenosides by the adventitious root cultures of ginseng, which are important secondary metabolites with pharmaceutical applications. The adventitious roots were cultured in bioreactors for 50 d using 1.5-strength Murashige and Skoog (MS) medium supplemented with 10 mg/l indole acetic acid and 75 g/l sucrose. Kinetic studies of the nutrient composition of the spent medium revealed the gradual depletion of various inorganic nutrients and sugars. Cultures were supplied with fresh nutrient medium (medium exchange or replenishment with 0.75- and 1.0-strength MS medium) after 10 and 20 d of culture initiation to fulfill the nutritional requirements of adventitious roots. Medium replenishment strategy (with 1.0-strength MS medium after 20 d of culture) significantly improved the growth of adventitious roots and the biosynthesis of ginsenosides by the adventitious roots. This work is useful for the large-scale cultivation of adventitious roots for the production of ginsenosides.

Function of nitric oxide and superoxide anion in the adventitious root development and antioxidant defence in Panax ginseng

The involvement of NO in O(2)(.-) generation, rootlet development and antioxidant defence were investigated in the adventitious root cultures of mountain ginseng. Treatments of NO producers (SNP, sodium nitroprusside; SNAP, S-nitroso-N-acetylpenicillamine; and sodium nitrite with ascorbic acid), and NO scavenger (PTIO, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl3-oxide) revealed that NO is involved in the induction of new rootlets. Severe decline in number of new rootlets compared to the control under PTIO treatment indicates that NO acts downstream of auxin action in the process. NO producers (SNP, SNAP and sodium nitrite with ascorbic acid) activated NADPH oxidase activity, resulting in greater O(2)(.-) generation and higher number of new rootlets in the adventitious root explants. Moreover, treatment of diphenyliodonium chloride, a NADPH oxidase inhibitor, individually or along with SNP, inhibited root growth, NADPH oxidase activity and O(2)(.-) anion generation. NO supply also enhanced the activities of antioxidant enzymes that are likely to be responsible for reducing H(2)O(2)levels and lipid peroxidation as well as modulation of ascorbate and non-protein thiol concentrations in the adventitious roots. Our results suggest that NO-induced generation of O(2) (.-) by activating NADPH oxidase activity is related to adventitious root formation in mountain ginseng.

Modulation of copper toxicity-induced oxidative damage by nitric oxide supply in the adventitious roots of Panax ginseng

Nitric oxide (NO) is a highly reactive, membrane-permeable free radical, which has recently emerged as an important signalling molecule and antioxidant. Here we investigated the protective effect of NO against the toxicity caused by excess CuSO(4) (50 microM) in the adventitious roots of mountain ginseng. It was found that NO donor, sodium nitroprusside (SNP), was effective in reducing Cu-induced toxicity in the mountain ginseng adventitious roots. Protective effect of SNP, as indicated by extent of lipid peroxidation, was reversed by incorporation of 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (CPTIO), a NO scavenger, in the medium suggesting that the protective effect of SNP is attributable to NO released, which was revealed from in situ confocal laser scanning microscopic localization of NO in the adventitious roots of mountain ginseng. Results obtained in the present study suggest that reduction of excess Cu-induced toxicity by SNP is most likely mediated through the modulation in the activities of antioxidant enzymes involved in H(2)O(2) detoxification (catalase, peroxidase, ascorbate peroxidase) and in the maintenance of cellular redox couples (glutathione reductase), and contents of molecular antioxidants (particularly non-protein thiol, ascorbate and its redox status). Exogenous NO supply also improved the activity of superoxide dismutase, an enzyme responsible for O*(2) (-) dismutation, and NADPH oxidase, an enzyme responsible for O*(2) (-) generation, in excess Cu supplied adventitious roots of mountain ginseng.

Improved production of caffeic acid derivatives in suspension cultures of Echinacea purpurea by medium replenishment strategy

The aim of this study was to produce caffeic acid derivatives from adventitious root cultures of Echinacea purpurea, which are of high pharmaceutical value. The effects of both media optimization and replenishment strategies were adopted to achieve improved production of E. purpurea adventitious roots and caffeic acid derivatives. Of the different media strengths (0.25 MS, 0.5 MS, 0.75 MS and 1 MS) tested for the culturing of adventitious roots in 5 L bioreactors, 0.5 MS medium was found to be most suitable for the growth of adventitious roots. The optima accumulation of biomass (73.6 g L(-1) FW and 10.03 g L(-1) DW), phenolics (61.14 mg g(-1) DW) and flavonoids (38.30 mg g(-1) DW) were achieved in this medium. Furthermore, fed batch cultivations (media replenishment with 0.25 MS, 0.5 MS, 0.75 MS and 1 MS at the end of 2nd and 3rd weeks) to further enhance the production of adventitious root biomass and metabolites were also attempted. High adventitious root biomasses (83.1 g L(-1) FW and 15.30 g L(-1) DW) were achieved with feeding of the 0.5 MS medium at the end of 2nd week. This led to slight decreases in the total production of phenolics and flavonoids; however, this feeding was responsible for increases in the accumulation of caftaric acid (5.76 mg g(-1) DW) and cichoric acid (26.12 mg g(-1) DW).

Combined effects of phytohormone, indole-3-butyric acid, and methyl jasmonate on root growth and ginsenoside production in adventitious root cultures of Panax ginseng C.A. Meyer

Indole-3-butyric acid at 25 microM with methyl jasmonate (MJ) at 100 microM in Panax ginseng synergistically stimulated both root growth and ginsenoside accumulation compared with 100 microM MJ alone. Productivity of ginsenoside was 10 mg l(-1) d(-1) compared to 7.3 mg l(-1) d(-1) with MJ elicitation alone.

Large-scale cultivation of adventitious roots of Echinacea purpurea in airlift bioreactors for the production of chichoric acid, chlorogenic acid and caftaric acid

Adventitious roots of Echinacea purpurea were cultured in airlift bioreactors (20 l, 500 l balloon-type, bubble bioreactors and 1,000 l drum-type bubble bioreactor) using Murashige and Skoog (MS) medium with 2 mg indole butyric acid l(-1) and 50 g sucrose l(-1) for the production of chichoric acid, chlorogenic acid and caftaric acid. In the 20 l bioreactor (containing 14 l MS medium) a maximum yield of 11 g dry biomass l(-1) was achieved after 60 days. However, the amount of total phenolics (57 mg g(-1) DW), flavonoids (34 mg g(-1) DW) and caffeic acid derivatives (38 mg g(-1) DW) were highest after 50 days. Based on these studies, pilot-scale cultures were established and 3.6 kg and 5.1 kg dry biomass were achieved in the 500 l and 1,000 l bioreactors, respectively. The accumulation of 5 mg chlorogenic acid g(-1) DW, 22 mg chichoric acid g(-1) DW and 4 mg caftaric acids g(-1) DW were achieved with adventitious roots grown in 1,000 l bioreactors.

Methyl jasmonate and salicylic acid induced oxidative stress and accumulation of phenolics in Panax ginseng bioreactor root suspension cultures

To investigate the enzyme variations responsible for the synthesis of phenolics, 40 day-old adventitious roots of Panax ginseng were treated with 200 microM methyl jasmonate (MJ) or salicylic acid (SA) in a 5 L bioreactor suspension culture (working volume 4 L). Both treatments caused an increase in the carbonyl and hydrogen peroxide (H2O2) contents, although the levels were lower in SA treated roots. Total phenolic, flavonoid, ascorbic acid, non-protein thiol (NPSH) and cysteine contents and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical reducing activity were increased by MJ and SA. Fresh weight (FW) and dry weight (DW) decreased significantly after 9 days of exposure to SA and MJ. The highest total phenolics (62%), DPPH activity (40%), flavonoids (88%), ascorbic acid (55%), NPSH (33%), and cysteine (62%) contents compared to control were obtained after 9 days in SA treated roots. The activities of glucose 6-phosphate dehydrogenase, phenylalanine ammonia lyase, substrate specific peroxidases (caffeic acid peroxidase, quercetin peroxidase and ferulic acid peroxidase) were higher in MJ treated roots than the SA treated ones. Increased shikimate dehydrogenase, chlorogenic acid peroxidase and beta-glucosidase activities and proline content were observed in SA treated roots than in MJ ones. Cinnamyl alcohol dehydrogenase activity remained unaffected by both MJ and SA. These results strongly indicate that MJ and SA induce the accumulation of phenolic compounds in ginseng root by altering the phenolic synthesis enzymes.

Effect of oxygen supply on cell growth and saponin production in bioreactor cultures of Panax ginseng

The effects of oxygen supply within the range 20.8-50% (using pure oxygen and air), on cell cultures of Panax ginseng were investigated in a balloon-type bubble bioreactor (5L capacity, containing 4 L Murashige and Skoog medium, supplemented with 7.0 mgL(-1) indolebutyric acid, 0.5 mgL(-1) kinetin and 30 gL(-1) sucrose). A 40% oxygen supply was found to be optimal for the production of both cell mass and saponin yielding values of 12.8 g(DW)L(-1), 4.5mg(gDW)(-1) on day 25, respectively. Low (20.8%, 30%) and high (50%) oxygen concentration supplies were unfavorable to cell growth and saponin accumulation. The results indicate that oxygen supplementation to bioreactor-based ginseng cultures was beneficial for biomass accumulation and saponin production.

Copper-induced changes in the growth, oxidative metabolism, and saponin production in suspension culture roots of Panax ginseng in bioreactors

Roots of Panax ginseng exposed to various concentrations of Cu (0.0, 5, 10.0, 25.0, and 50.0 microM) accumulated high amounts of Cu in a concentration-dependent and duration-dependent manner. Roots treated with 50 microM Cu resulted in 52% and 89% growth inhibition after 20 and 40 days, respectively. Saponin synthesis was stimulated at a Cu concentration between 5 and 25 muM but decreased at 50 microM Cu. Malondialdehyde content (MDA), lipoxygenase activity (LOX), superoxide ion (O2*-) accumulation, and H2O2 content at 5 and 10 microM Cu-treated roots were not increased but strongly increased at 50 microM Cu resulting in the oxidation of ascorbate (ASC) and glutathione (GSH) to dehydroascorbate (DHA) and glutathione disulfide (GSSG), respectively indicating a clear oxidative stress. Seven well-resolved bands of superoxide dismutase (SOD) were detected in the gel and an increase in SOD activity seemed to be mainly due to the induction of Fe-SOD 3. Five to 10 microM Cu slightly induced activity of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR), guaiacol peroxidase (G-POD) but inhibited monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR) enzyme activities. No changes in catalase (CAT) activity and in activity gel were found up to 25 microM Cu, but both G-POD and CAT activities were inhibited at 50 microM Cu. Glutathione metabolism enzymes such as gamma-glutamylcysteine synthetase (gamma-GCS), glutathione-S-transferase (GST), and glutathione peroxidase activities (GPx) were activated at 5 and 10 microM Cu but were strongly inhibited at 50 microM Cu due to the Cu accumulation in root tissues. The strong depletion of GSH at 50 microM Cu was associated to the strong induction of gamma-glutamyltranspeptidase (gamma-GGT) activity. These results indicate that plant could grow under Cu stress (5-25 microM) by modulating the antioxidant defense mechanism for combating Cu induced oxidative stress.

Methyl jasmonate and salicylic acid elicitation induces ginsenosides accumulation, enzymatic and non-enzymatic antioxidant in suspension culture Panax ginseng roots in bioreactors

The effects of methyl jasmonate (MJ) and salicylic acid (SA) on changes of the activities of major antioxidant enzymes, superoxide anion accumulation (O2-), ascorbate, total glutathione (TG), malondialdehyde (MDA) content and ginsenoside accumulation were investigated in ginseng roots (Panax ginseng L.) in 4 l (working volume) air lift bioreactors. Single treatment of 200 microM MJ and SA to P. ginseng roots enhanced ginsenoside accumulation compared to the control and harvested 3, 5, 7 and 9 days after treatment. MJ and SA treatment induced an oxidative stress in P. ginseng roots, as shown by an increase in lipid peroxidation due to rise in O2- accumulation. Activity of superoxide dismutase (SOD) was inhibited in MJ-treated roots, while the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), SOD, guaiacol peroxidase (G-POD), glutathione peroxidase (GPx) and glutathione reductase (GR) were induced in SA-treated roots. A strong decrease in the activity of catalase (CAT) was obtained in both MJ- and SA-treated roots. Activities of ascorbate peroxidase (APX) and glutathione S transferase (GST) were higher in MJ than SA while the contents of reduced ascorbate (ASC), redox state (ASC/(ASC+DHA)) and TG were higher in SA- than MJ-treated roots while oxidized ascorbate (DHA) decreased in both cases. The result of these analyses suggests that roots are better protected against the O2- stress, thus mitigating MJ and SA stress. The information obtained in this work is useful for efficient large-scale production of ginsenoside by plant-root cultures.

Hyperhydricity in apple: ultrastructural and physiological aspects

We studied the effects of hyperhydricity on subcellular ultrastructure and physiology of leaves during in vitro regeneration of apple plants. Morphological, anatomical and ultrastructural differences between healthy leaf tissues obtained from greenhouse-grown plants and healthy and hyperhydric leaves obtained from shoots raised from nodal shoot explants in a bioreactor were investigated by electron microscopy and confocal laser scanning microscopy. Compared with healthy leaves, hyperhydric leaves showed abnormal, often discontinuous development of the epidermis and cuticle. Stomata were malformed. The leaf lamina appeared thickened and was characterized by poor differentiation between the palisade and spongy mesophyll tissue. Hyperhydric leaves had a significantly lower chloroplast number per cell and chloroplasts showed reduced thylakoid stacking compared with healthy leaves. Hyperhydricity resulted in a general decrease in concentrations of reduced and oxidized pyridine nucleotides, reflecting a reduction in metabolic activity. The activities of antioxidant enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase were higher in hyperhydric leaves than in healthy leaves, indicating that hyperhydricity was associated with oxidative stress. Chlorophyll fluorescence measurements provided evidence of oxidative damage to the photosynthetic machinery in hyperhydric leaves: photochemical efficiency of photosystem II, effective quantum efficiency and photochemical quenching were all lower in hyperhydric leaves compared with healthy leaves.

Application of bioreactor system for large-scale production of Eleutherococcus sessiliflorus somatic embryos in an air-lift bioreactor and production of eleutherosides

Embryogenic callus was induced from leaf explants of Eleutherococcus sessiliflorus cultured on Murashige and Skoog (MS) basal medium supplemented with 1 mg l(-1) 2,4-dichlorophenoxyacetic acid (2,4-D), while no plant growth regulators were needed for embryo maturation. The addition of 1 mg l(-1) 2,4-D was needed to maintain the embryogenic culture by preventing embryo maturation. Optimal embryo germination and plantlet development was achieved on MS medium with 4 mg l(-1) gibberellic acid (GA(3)). Low-strength MS medium (1/2 and 1/3 strength) was more effective than full-strength MS for the production of normal plantlets with well-developed shoots and roots. The plants were successfully transferred to soil. Embryogenic callus was used to establish a suspension culture for subsequent production of somatic embryos in bioreactor. By inoculating 10 g of embryogenic cells (fresh weight) into a 3l balloon type bubble bioreactor (BTBB) containing 2l MS medium without plant growth regulators, 121.8 g mature somatic embryos at different developmental stages were harvested and could be separated by filtration. Cotyledonary somatic embryos were germinated, and these converted into plantlets following transfer to a 3l BTBB containing 2l MS medium with 4 mg l(-1) GA3. HPLC analysis revealed that the total eleutherosides were significantly higher in leaves of field grown plants as compared to different stages of somatic embryo. However, the content of eleutheroside B was highest in germinated embryos. Germinated embryos also had higher contents of eleutheroside E and eleutheroside E1 as compared to other developmental stages. This result indicates that an efficient protocol for the mass production of E. sessiliflorus biomass can be achieved by bioreactor culture of somatic embryos and can be used as a source of medicinal raw materials.

CO(2)-induced total phenolics in suspension cultures of Panax ginseng C. A. Mayer roots: role of antioxidants and enzymes

The effects of different concentrations of CO(2) (1%, 2.5% and 5%) on the antioxidant capacity, total phenols, flavonoids, protein content and phenol biosynthetic enzymes in roots of Panax ginseng were studied in bioreactor (working volume 4 l) after 15, 30 and 45 days. CO(2) induced accumulation of total phenolics in a concentration and duration dependent manner. Total phenols, flavonoids and 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity increased 60%, 30% and 20% at 2.5% CO(2) after 45 days compared to control in P. ginseng roots which indicated that phenolics compounds played an important role in protecting the plants from CO(2). Hypothesizing that increasing the phenolic compounds in roots of P. ginseng may increase its nutritional functionality; we investigated whether pentose phosphate pathway (PPP), shikimate/phenylpropanoid pathway enzymes have a role in phenolics mobilization in P. ginseng roots. Fresh weight (FW), dry weight (DW) and growth ratio was increased at 1% and 2.5% CO(2) only after 45 days, however, unaffected after 15 and 30 days. Results also indicated that high CO(2) progressively stimulated the activities of glucose 6 phosphate dehydrogenase (G6PDH, E.C. 1.1.1.49), shikimate dehydrogenase (SKDH, E.C. 1.1.1.25), phenylalanine ammonia lyase (PAL, E.C. 4.3.1.5), cinnamyl alcohol dehydrogenase (CAD, E.C. 1.1.1.195), caffeic acid (CA) peroxidase and chlorogenic acid (CGA) peroxidase after 15, 30 and 45 days. Increased CO(2) levels resulted in increases in accumulation of total protein (45%), non-protein thiol (NP-SH) (30%) and cysteine contents (52%) after 45 days compared to control and increased activities of beta-glucosidase (GS, E.C. 3.2.1.21) and polyphenol oxidase (PPO, E.C. 1.10.3.2) in P. ginseng roots indicated that they played an important role in protecting the plants from CO(2). These results strongly suggest that high concentration of CO(2) delivered to ginseng root suspension cultures induced the accumulation of total phenolics possessing high antioxidant properties probably useful for human health. Therefore, roots of P. ginseng are considered as a good source of phenolics compounds with high antioxidants capacity and can be produced on a large scale.

Production of eleutherosides in in vitro regenerated embryos and plantlets of Eleutherococcus chiisanensis

High frequency somatic embryogenesis of Eleutheorcoccus chiisanensis was achieved through suspension culture of embryogenic cells in hormone-free Murashige and Skoog liquid medium supplemented with 30 g sucrose l-1. Cotyledonary somatic embryos were germinated and converted into plantlets using 20 microM: gibberellic acid which were then grown in a 10 l airlift bioreactor. HPLC analysis revealed the accumulation of eleutheroside B, E and E1 in the embryos and plantlets. Thus mass production of embryos and plantlets of E. chiisanensis can be achieved in liquid cultures and the biomass produced may become an alternative source of eleutherosides.

Effects of temperature on oxidative stress defense systems, lipid peroxidation and lipoxygenase activity in Phalaenopsis

Higher plants growing in natural environments experience various abiotic stresses. The aim of this study was to determine whether exposure to temperature-stress would lead to oxidative stress and whether this effect varied with different exposure periods. The thermal dependencies of the activities of protective enzymes, photosynthetic efficiency (Fv/Fm), protein, non-protein thiol (NP-SH), cysteine content, lipoxygenase (LOX) activity (EC 1.13.11.12) and malondialdehyde (MDA) content at 25-40 degrees C were determined for 4, 24 and 48 h in leaf and root segments of Phalaenopsis. The increase in MDA level and LOX activity may be due to temperature-associated oxidative damage to leaf and root segments. Temperature-stress induced not only activities of active oxygen species (AOS) scavenging enzymes but also protein, NP-SH and cysteine content in both leaf and root segments at 30 degrees C for 4 and 24 h (except for 48 h in some cases) compared to 25 degrees C-and greenhouse-grown leaf and root segments indicating that antioxidants enzymes played an important role in protecting plant from temperature-stress. However, activities of dehydroascorbate reductase (DHAR, EC 1.8.5.1), glutathione peroxidase (GPX, EC 1.11.1.9) and glutathione-S-transferase (GST, EC 2.5.1.18) in leaf and root, glutathione reductase (GR, EC 1.6.4.2) in leaf and guaiacol peroxidase (G-POD, 1.11.1.7) in root segments were induced significantly at 40 degrees C compared to 25 degrees C and greenhouse-grown plants suggesting that these enzymes play protective roles at high temperature. In contrast, activities of superoxide dismutase (SOD, EC 1.15.1.1) and monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) in leaf and root, catalase (CAT, EC 1.11.1.6) in root, GR in root, and protein, cysteine, NP-SH content in both root and leaf and Fv/Fm ratio were diminished significantly at 40 degrees C compared to 25 degrees C-and greenhouse-grown plants. These indicate that these enzymes were apparently not involved in detoxification process and sensitive at higher temperature. Also, the close relation between activities of enzymes with their metabolites at 30 degrees C than 40 degrees C indicated that the antioxidants enzymes and metabolites both may play an important role in protecting cells against the temperature-stress.

Methyl jasmonate elicitation enhanced synthesis of ginsenoside by cell suspension cultures of Panax ginseng in 5-l balloon type bubble bioreactors

The effects of methyl jasmonate (MJ) elicitation on the cell growth and accumulation of ginsenoside in 5-l bioreactor suspension cultures of Panax ginseng were investigated. Ginsenoside accumulation was enhanced by elicitation by MJ (in the range 50-400 microM); however, fresh weight, dry weight and growth ratio of the cells was strongly inhibited by increasing MJ concentration. The highest ginsenoside yield was obtained at 200 microM MJ. In the second experiment, 200 microM MJ was added on day 15 during the cultivation. The ginsenoside, Rb group, and Rg group ginsenoside content increased 2.9, 3.7, and 1.6 times, respectively, after 8 days of MJ treatment. Rb group gisnsenosides accumulated more than Rg group ginsenosides. Among Rb group ginsenosides, Rb1 content increased significantly by four times but the contents of Rb2, Rc and Rd increased only slightly. Among Rg group ginsenosides, Rg1 and Re showed 2.3-fold and 3.0-fold increments, respectively, whereas there was only a slight increment in Rf group ginsenosides. These results suggest that MJ elicitation is beneficial for ginsenoside production using 5-l bioreactor cell suspension cultures.