Plant cell and organ cultures as a source of phytochemicals

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/67430Plant cell and organ cultures constitute a promising platform for the production of numerous valuable secondary compounds. Currently, in vitro culture techniques involve both empirical and rational approaches as suitable strategies to condition high metabolite production and establish competitive plant cell-based bioprocesses. In this context, we have developed hairy root cultures of Panax ginseng, and engineered hairy root cultures of Duboisia, Datura metel and Hyoscyamus spp and plant cell cultures of Centella asiatica and Taxus spp. This chapter describes our work on the development of two different biotechnological systems to improve taxol production in cell suspension cultures of Taxus spp and ginsenoside production in hairy root cultures of Panax ginseng

Comprehensive characterization of a time-course transcriptional response induced by autotoxins in Panax ginseng using RNA-Seq

The lists for all the differentially expressed genes. (XLS 1362 kb

Studies on saponin production in tropical medicinal plants Maesa argentea and Maesa lanceolata

The continuous need for new compounds with important medicinal activities has lead to the identification and characterization of various plant-derived natural products. As a part of this program, we studied the saponin production from two tropical medicinal plants Maesa argentea and M. lanceolata and evaluated several treatments to enhance their saponin production. In this experiment, we present the analyses of saponin production from greenhouse grown plants by means of TLC and HPLC-MS. We observed that the content of saponin from these plants varied depending on organ and physiological age of the plants. In addition, the impact of elicitors on saponin accumulation on in vitro grown plants was analyzed using TLC. The production of saponin was very stable and not affected by treatment with methyl jasmonate, and salicylic acid. In conclusion, Maesa saponins are constitutively produced in plants and the level of these compounds in plants is mainly affected by the developmental or physiological stage

Characterization of thermophilic β-Glucosidase of rhizospheric bacterial strain (LSKB15) isolated from Cholistan Desert, Pakistan

Fifty thermophilic bacterial strains isolated from rhizospheric soil of Cholistan desert, Pakistan, and designated as LSKB01-LSKB50 were screened for β-glucosidase gene (bgl) belonging to glycoside hydrolase family 1 (GH 1) using PCR technique. Subsequently, the same strains were screened for extracellular β-glucosidase production using esculin as substrate. All fifty strains were shown to be amplified for conserved region of bgl gene and to secrete extracellular β-glucosidase. One strain (LSKB15) secreted relative high amount of this enzyme as indicating by size of ferric-esculetin precipitate. This strain was further cultivated on cellulose containing media and β-glucosidase was purified by ammonium sulfate, dialysis and gel filtration chromatography. The purified enzyme showed an optimal temperature of 60°C and an optimal pH of 7. It also showed excellent temperature and pH stability retaining > 90% activity after incubation for 2 h at pH 5-8 and 40-60°C. Finally, the purified enzyme was run on Native-PAGE and subsequently incubated in phosphate buffer containing 5 mM of 4-methylumbelliferyl-β-D-glucoside (4-MUG) for 15 min at 50°C and visualized by UV light as white band. We concluded that thermophilic LSKB15 β- glucosidase may work with other cellulase to degrade available cellulose synthesized by plant and the properties exhibited by it such as high temperature and pH stability pointed out its potential industrial importance

Ginsenosides are novel naturally-occurring aryl hydrocarbon receptor ligands.

The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that mediates many of the biological and toxicological actions of structurally diverse chemicals. In this study, we examined the ability of a series of ginsenosides extracted from ginseng, a traditional Chinese medicine, to bind to and activate/inhibit the AHR and AHR signal transduction. Utilizing a combination of ligand and DNA binding assays, molecular docking and reporter gene analysis, we demonstrated the ability of selected ginsenosides to directly bind to and activate the guinea pig cytosolic AHR, and to stimulate/inhibit AHR-dependent luciferase gene expression in a recombinant guinea pig cell line. Comparative studies revealed significant species differences in the ability of ginsenosides to stimulate AHR-dependent gene expression in guinea pig, rat, mouse and human cell lines. Not only did selected ginsenosides preferentially activate the AHR from one species and not others, mouse cell line was also significantly less responsive to these chemicals than rat and guinea pig cell lines, but the endogenous gene CYP1A1 could still be inducted in mouse cell line. Overall, the ability of these compounds to stimulate AHR signal transduction demonstrated that these ginsenosides are a new class of naturally occurring AHR agonists

Microbial β-Glucosidase: sources, production and applications

Cellulose is the most abundant biopolymer in biosphere and the major constituent of plant biomass. Cellulose polymer is made up of β-glucose units linked by β-glucosidic bonds. Cellulase is an enzymatic system that catalyzes the hydrolysis of cellulose polymer to glucose monomers. This enzymatic system consists of three individual enzymes namely endoglucanase, exoglucanase and β-glucosidase which act synergistically to degrade cellulose molecules into glucose. Cellulases are produced by bacteria, fungi, plants, and animals and used in many industrial applications such as textile industries, laundry and detergent industries, paper and pulp industry, animal feeds, and biofuels production. β-Glucosidase is a diverse group of enzymes with wide distribution in bacteria, fungi, plants and animals and has the potential to be utilized in various biotechnological processes such as biofuel production, isoflavone hydrolysis, flavor enhancement and alkyl/aryl β-D-glucoside and oligosaccharides synthesis. Thus, there is increased demand of β-glucosidase production from microbial sources under profitable industrial conditions. In this review, β-glucosidase classification, localization, and mechanism of action will be described. Subsequently, the various sources of β-glucosidase for industrial sector will be discussed. Moreover, Fermentation methods and various parameters affecting β-glucosidase production will be highlighted on the light of recent findings of different researchers. Finally, β-glucosidase applications in biofuel production, flavors enhancement, isoflavones hydrolysis, cassava detoxification and oligosaccharide synthesis will be described

Microbial β-Glucosidases: screening, characterization, cloning and applications

Cellulose is the most abundant biomaterial in the biosphere and the major component of plant biomass. Cellulase is an enzymatic system required for conversion of renewable cellulose biomass into free sugar for subsequent use in different applications. Cellulase system mainly consists of three individual enzymes namely: endoglucanase, exoglucanase and β-glucosidases. β-Glucosidases are ubiquitous enzymes found in all living organisms with great biological significance. β-Glucosidases have also tremendous biotechnological applications such as biofuel production, beverage industry, food industry, cassava detoxification and oligosaccharides synthesis. Microbial β-glucosidases are preferred for industrial uses because of robust activity and novel properties exhibited by them. This review aims at describing the various biochemical methods used for screening and evaluating β-glucosidases activity from microbial sources. Subsequently, it generally highlights techniques used for purification of β-glucosidases. It then elaborates various biochemical and molecular properties of this valuable enzyme such as pH and temperature optima, glucose tolerance, substrate specificity, molecular weight, and multiplicity. Furthermore, it describes molecular cloning and expression of bacterial, fungal and metagenomic β-glucosidases. Finally, it highlights the potential biotechnological applications of β-glucosidases

An intestinal bacterial metabolite (M1) of ginseng protopanaxadiol saponins inhibits tumor-induced neovascularization

The present study demonstrated that an intestinal bacterial metabolite (M1) of protopanaxadiol-type ginsenosides significantly inhibited the growth of implanted tumor and the intrahepatic metastasis by the implantation of a small fragment of colon 26-L5 tumor into the liver when it was administered orally. These findings indicates that M1 was effective for the inhibition of the growth and metastasis of colon26-L5 cells in addition to lung metastasis of B16-BL6 melanoma cells as have been reported previously. The conditioned medium of colon 26-L5 cellS (CM-L5) induced in vitro tube formation of hepatic sinusoidal endothelial (HSE) cells on Matrigel-coated substrates, which is considered to be an important step in the processes of tumor angiogenesis. \u27This activity of CML5 was abrogated by noncytotoxic concentrations of M1 in a concentration-dependent manner. Similarly, M1 eliminated the ability of CM-L5 to promote the migration of HSE cells concentration-dependently. These findings indicate that M1-induced inhibition of tumor growth and intrahepatic metastasis may be partly related to the suppression of tumor angiogenic responses including capillary tube formation and migration of HSE cells. 本研究では,薬用人参(Panax ginseng C.A.MEYER)のprotopanaxadiol-type ginsenosidesの主要な腸内細菌代謝物M1の経口投与は,マウス結腸癌colon 26-L5細胞の腫瘍小片を肝へ直接移植した後の移植部位での増殖と肝内移転に対して有意に抑制効果を示すことを明らかにした。この結果は,B16-BL6メラノーマ細胞による肺転移を抑制した以前の報告と同様に,co1on 26-L5細胞に対しても有効であることが示された。肝類洞内度細胞(HSE細胞)をマトリゲルをコートした基質上で,colon 26-L5細胞の培養上清(CM-L5)とともに培養すると,腫瘍血管新生の週程における重要なステップのひとつである,内度細胞の菅腔形成を誘導した。CM-L5による菅形成能は,細胞傷害性を示さない濃度範囲のM1により,濃度依存的に抑制された。同様に,CM-L5によるHSE細胞の移動能の亢進を,M1は濃度に依存して抑制した。以上,M1による結腸癌の肝における増殖及び肝内転移の抑制は,内度細胞の骨腔形成及ぴ移動能を含む血管新生反応の抑制と部分的に関係していることが示唆された