Medium plant culture

H. Gagnon, 3. Seguin, E. Bleichert, S. Tahara, and R. K. Ibrahim, Biosynthesis of white lupin isoflavonoids from (U- C]L-phenylalanine and their release into the culture medium. Plant Physiol. 100 16 (1992). 

Plant material was transferred into Petri dishes in liquid Mohr medium and cultured in a climatic chamber in the conditions described above. 

As well as overcoming many of the inherent problems associated with agriculture, plant tissue culture also offers a number of advantages over conventional animal cell culture methods currently being applied to produce biopharmaceutical proteins commercially [8], As plant culture media are relatively simple in composition and do not contain proteins, the cost of the process raw materials is reduced and protein recovery from the medium is easier and cheaper compared with animal cell culture. In addition, as most plant pathogens are unable to infect humans, the risk of pathogenic infections being transferred from the cell culture via the product is also substantially reduced. 

Alterations to the proteins and pre-proteins expressed by cultured plant cells have been used to facilitate product recovery. A leader sequence is required for foreign protein secretion from plant cells into the apoplast and then into the culture medium. As indicated in Table 2.1, plant, mammalian and viral sequences have been employed to achieve the entry of transgenic proteins into the bulk-flow pathway in plant cultures. 

The presence of foreign protein in the medium of plant cultures does not necessarily mean that all or even most of the product can be recovered from the medium. In many expression systems where an appropriate signal sequence has been used, considerable amounts of foreign protein remain within the plant cells and/or tissues. For example, in a comparison of IgG antibody production in tobacco cell suspension and hairy root cultures, a maximum of 72% of the total antibody was found in the medium of the suspension cultures whereas only 26% was found in the medium of the hairy root cultures [17]. This result could indicate that secretion and/or transport across the cell wall was slower in the hairy roots alternatively, it could indicate poorer stability of the secreted protein in the hairy root medium. If foreign proteins are to be purified from the medium, improved secretion and extracellular product stability are desirable. 

There have been many reports from several groups that plant culture medium is not conducive to protein stability, and that the retention of secreted proteins in culture media can be very poor [10, 11, 17, 40, 60, 63-66]. The mechanisms responsible for protein loss from plant culture media are not completely understood however, current indications are that multiple factors may be involved. Processes that have been proposed to affect foreign proteins in plant media include protein degradation due to protease activity [10, 17, 20, 38, 60, 65], protein instability due to defined or... 

Medium for Culture of Pollen Tubes of Flowering Plants... 

Rhizosecretion is easy to scale up and very cost effective with respect to isolation and purification. However, the bioreactor systems used for hairy root cultures differ from those used for plant cell suspensions. Traditional bioreactor systems have recently been adapted for root culture, and this technology is now being taken to commercial scales. The most traditional system is the airlift bioreactor used for microorganisms or plant cells. This system is adapted for the culturing of roots in liquid medium. Mist culture systems have also been developed. For this technology, the volume of the culture medium is reduced and the concentration of the secreted therapeutic protein is increased. If the protein to be produced is known to be quite stable, then a less expensive hydroponic culture can be designed in a manner suitable for scale-up. 

GANTET, P IMBAULT, N THIERSAULT, M., DOIREAU, P Necessity of a functional octadecanoic pathway for indole alkaloid synthesis by Catharanthus roseus cell suspensions cultured in an auxin-starved medium. Plant Cell Physiol., 1998,39,220-225. 

Subculture See Passage . With plant cultures, this is the process by which the tissue or explant is first subdivided and then transferred into fresh culture medium. 

Fig. (4). Regenerated plant cultured on B5 basal medium containing 3 mg/l lAA...

A Shoot regeneration on the transformed roots cultured on HF 1/2 MS solid medium at 25°C in the dark for 6 months. B Aberrant feature of leaves (three leaves) observed in the transformed shoot cultured on HF B5 solid medium at 25°C under 16 hr light. C Comparison between transformed (left) and non-transformed (right) plants cultured on HF B5 solid medium at 25°C under 16 hr light. 

Roots have cation exchange properties that correspond closely to those exhibited by soils. They are believed to act as amphoteric colloids and absorb cations from the plant culture solution or soil. Cations are held by the roots when they are placed in water but may be set free when other cations are added to the culture medium. They are also readily removed by electrodialysis, and this serves as a convenient way of measuring root CEC. The accuracy of this method has been questioned because of the uncertainty as to whether this procedure removes all of the exchangeable cations, and only these. Furthermore, some organic substances may also be removed, leaving hydrogen ions adsorbed on the root surface. 

Callus culture culture of cell mass on solid media (e.g., agar). The culture is initiated using an explant of a seedling or other plant source. An explant is living tissue excised aseptically from the natural site of growth and placed in a medium for culture. 

It is well known that the elicitors are compounds that can induce defense responses on plant cultures deriving in an increase on secondary metabolites production [42]. In addition, it was frequently observed that these compounds were able to release the plant products formed to the medium [42]. 

Resistance to Proteolysis. As the peptides were expected to be either secreted from plant cells in transgenic plants or applied to the external surfaces of plant tissues, the extracellular proteases present in the intercellular spaces of plant tissues were considered to be most important. Accordingly, peptides were tested against crude preparations of enzymes from the extracellular fluid (ECF) of plant leaves. Extracellular fluids from leaves of maize, tobacco and potato, and spent medium from cultured plant cells produced similar results tobacco ECF was used routinely. 

Culture medium Plant organ analysed Fresh weight (mg/plant) Stimulation (%)... 

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