Cell culture cultivation

The problems with jojoba as a commercial crop are the usual ones of domestication and cultivation. It is a slow-growing plant, available only in the wild and therefore has very wide genetic variabiUty. Efforts are underway to select the most promising variants and cultivate these as a crop in the southwestern United States deserts (7). A possible alternative for producing jojoba oil is to culture plant embryos in bioreactors (see Cell culture technology). 

Soule et al. [141] constructed a sparged, concentric cylinder bioreactor for the cultivation of suspensions of Pirus malus. Growth was reduced under all rotational conditions. Sun and Linden [106] employed a rotating wall vessel (Rotary Cell Culture System, Synthecon, Houston, TX, USA) to cultivate suspensions of Taxus cuspidata under laminar flow conditions. Shear rates were... 

A considerable amount of extracellular polysaccharides is produced in the process of cultivation of certain plant suspension cultures and the spent culture medium has proved to be an accessible source for their production (1-3). The interest in investigating these extracellular polysaccharides has been quite strong over the past 10-15 years, motivated by their biological activity (4,5). Plants of the Asteraceae family, as well as their cell cultures, have been established to contain polysaccharides with immunostimulating activity (1-6). The object of our research was Helianthus annuus 1805 cell culture (Asteraceae), which according to the preliminary investigation produces a considerable amount of exopolysaccharides. 

With animal viruses, the initial host may be a whole animal which is susceptible to the virus, but for research purposes it is desirable to have a more convenient host. Many animal viruses can be cultivated in tissue or cell cultures, and the use of such cultures has enormously facilitated research on animal viruses. 

Classification of animal viruses Most of the animal viruses which have been studied in any detail have been those which have been amenable to cultivation in cell cultures. As seen, animal viruses are known with either single-stranded or doublestranded DNA or RNA. Some animal viruses are enveloped, others are naked. Size varies greatly, from those large enough to be just visible in the light microscope, to those so tiny that they are hard to see well even in the electron microscope. In the following sections, we will discuss characteristics and manner of multiplication of some of the most important and best-studied animal viruses. 

Insect cell systems represent multiple advantages compared with mammalian cell cultures (1) they are easier to handle (Table 2.1) (2) cultivation media are usually cheaper (3) they need only minimum safety precautions, as baculovirus is harmless for humans (4) they provide most higher eukaryotic posttranslational modifications and heterologous eukaryotic proteins are usually obtained in their native conformation (5) the baculovirus system is easily scalable to the bioreactor scale. However, because of the viral nature of the system, continuous fermentation for transient expression is not possible - the cells finally die. 

The culture module greatly facilitated homogeneous distribution of seeded cells and cultivation of a large number of cells under identical conditions. In addition, the module required a smaller volume of medium than standard cell culture systems. Importantly, this modular system provides the great advantages of scalability and safety because cell processing can be performed in a closed system. Thus, the modules facilitate the production of cells that are safe for use in cell transplantation therapies. 

Although plant cell culture is not as cost effective as plant cultivation in the open field, it will become an economical process if higher protein yields can be achieved [58]. The cultivation medium of plants is chemically defined, consisting of a carbon source, minerals, vitamins and phytohormones [69]. Furthermore, it is protein-free and relatively inexpensive. In contrast, animal cells often require complex supplements such as fetal calf serum and/or expensive growth factors, although serum-free cultivation is possible in case of Chinese hamster ovary (CHO) cells [70]. 

Although cell cultures produce a much lower amount of biomass than plants cultivated in the open field, tobacco suspension cells have been cultivated at volumes of up to 20 m3 (see [61] and references therein). 

Definition of a toxicity with culture of the primerely trepsinised chicken fibroblasts (TCF) included the following stages - incubation of chicken embryo within 11 day - tripsinisation and cultivation of a TCF cells monolayer - 2 days - contact of the tested preparation with the TCF cells monolayer an and the count of a toxicity by the citopathogenic action (CPA)-1-5 day. Hence, definition of a toxicity on cell culture borrowed 14-18 days and at the last two stages demanded strict sterility. 

Calf serum was added to the medium for cell culture to 10% concentration. T98G or U937 cells were seeded onto 25 cm2 flasks for cell culture (Nunc, Denmark). Cells were cultivated for 72 h without serum, with 10% of intact serum or 10% serum after 6 h of photodynamic treatment. After the incubation period cells were harvested with chymotrypsine and their number was calculated in a hemocy-tometer chamber. 

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