Master cultures

For most species of bacteria, subculturing the master cultures once a month is adequate. Lactobacilli may require subculturing more frequendy, whilst yeasts and flagellates such as Euglena, can be subcultured every 3-6 months. 

Stock cultures (or master cultures) are typically kept in cultures tubes (e.g. 10-20 ml) or small glass flasks (125-500 ml) fitted with a cotton wool... 

The master culture is stored at 4 C. from this, submaster cultures are prepared weekly. Transfers are made daily into peptone-water inoculum medium and incubated at 37 C. for 24 hours. 

The ability in mastering culture values in different con-texts is a main attitude for (architectural) designing. Constructing connections between different contexts activates building up experience in terms of seeing, interpreting and doing. ... 

Biotechnology feniientation/ cell culture Establishment of master cell bank and working cell bank Maintenance of working cell bank Cell culture and/or fermentation Isolation and purification Physical processing, and packaging... 

Possible contamination by chemical or biological substances is one of the most important concerns when producing pharmaceutical proteins. Plant cell cultures ensure the production of the desired protein in a controlled, sterile and sealed environment and can be adapted to cGMP conditions. Therefore, the risk of contamination is minimized and the production conditions can be modified more easily in a contained reactor than in the field. Another advantage is the ability to freeze plant suspension cells in liquid nitrogen [66, 67] so that master and working cell banks can be established, a prerequisite for cGMP procedures [68]. 

The cell bank s construction design is normally two tiered, consisting of a master cell bank and a working cell bank (Figure 5.6). The master cell bank is constructed first, directly from a culture of the newly constructed production cell line. It can consist of several hundred individually stored ampoules. 

Master and working banks of both the viral vector and the animal cell line will have been constructed during the drug development process (see Chapter 4). Manufacture of a batch of vector, therefore, will be initiated by the culture of packing cells in suitable animal cell bioreactors. The... 

In order to prevent the unwanted drift of properties which might ensue from repeated subcultures or multiple generations, the production of biological medicinal products obtained by microbial culture, cell culture or propagation in embryos and animals should be based on a system of master and working seed lots and/or cell banks. 

As it is imperative that the plant-derived hiopharmaceutical product must be obtained repeatedly and on a consistent basis, a master cell culture bank, seed bank for transgenic plants, or virus seed stock for transient expression systems must be constantly maintained. Storage conditions must therefore he optimized to prevent contamination and ensure viability. Both transgene stability (e.g., reversion to wild type or sequence drift of plant virus expression vectors) and protein expression levels must be monitored in a representative plant of a given bank or stock to minimize any possible variation in expression levels that may affect safety and consistency of the hnal product. A program that monitors lot-to-lot consistency of the hiochemical and biological properties by comparing the product with appropriate in-house reference standards could he implemented as a fundamental component of product development. 

Of the elements that have shaped the fates of civilizations, arguably none has been more instrumental than the martial metal, that most stable of elements iron. The Hittites of Asia Minor in the thirteenth century bc seem to have been the first culture to smelt and forge iron systematically, and this gave their armies an edge, quite literally, over their rivals. The militaristic Assyrians mastered the art around the ninth century bc, and no opponent could resist their brutal iron fist for several centuries. 

Replica plating. A technique in which an impression of a culture is taken from a master plate and transferred to a fresh plate. The impression can be of bacterial clones or phage plaques. 

For several centuries, the development of the alphabet affected most people indirectly in the cultures where it was used. Written language was difficult to master its utilization was often reserved for scribes, philosophers, and priests. The invention of the printing press and movable type made reading a common skill and, according to Marshall McLuhan... 

Choose one of the clones from the final (100% efficiency) cloning as the master cell line, expand it in tissue culture and cryogenically preserve stocks of it as the master cell bank (at least 12 vials). 

Freshney RI (2000), Introduction to basic principles, In Masters JRW (Ed.), Animal Cell Culture A Practical Approach, Oxford University Press, New York, pp. 1-16. 

As a quality control, some flasks of this bank (about two or three) should be used to confirm that the cell bank concentration and viability are satisfactory and free of contaminants. Then, a flask of the bank should be thawed and the cells cultured to obtain a working bank. The size of this bank will depend on the future demand. At this stage it is important to confirm that the master and the work banks are genetically identical. 

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