Earle’s BSS

As well as being essential for certain reactions Na+ and, to a lesser extent, K+ are important in maintaining the osmotic balance in the cell. The sodium ion concentration is maintained about isotonic largely by the NaCl in the BSS but in Earle s BSS this is supplemented with NaHC03 and to a lesser extent with other salts (see Appendix 1). If the Na+ concentration is increased from the normal 120 mM up to 220 mM it leads to a dissociation of polysomes with concomitant inhibition of protein synthesis and cell growth (Fig. 5.1) (Saborio et al., 1974). 

There are a number of media available which are not based on a detailed investigation of growth requirements, but rather include crude mixtures of nutrients added to promote cell growth. These include lactalbumin hydrolysate (Appendix 1 Table 9) or yeast extract (Appendix 4) to provide an inexpensive source of amino acids or vitamins. Thus Melnick s monkey kidney media A and B (Melnick, 1955) contain lactalbumin hydrolysate and calf serum in Hanks and Earle s BSS, respectively. Chick embryo extract and tryptose phosphate broth (Appendix 1, Tables 11 and 12) are also used occasionally and their use is referred to where appropriate throughout the book. Mitsuhashi and Maramorosch mosquito cell medium contains lactalbumin hydrolysate, yeast extract and foetal calf serum in a specially developed saline (Mitsuhashi and Maramorosch, 1964 Singh, 1967). 

CMF (calcium- and magnesium-free BSS) is Earle s BSS made up without the calcium and magnesium. 

The amino acids and vitamins are made up in either Earle s or Hanks BSS. Dulbecco s modification is made up in Earle s BSS containing extra bicarbonate (3.7 g/1) and glucose (4.5 g/1) and supplemented with ferric nitrate (0.1 mg Fe(N03)3-9H20/1). 

Originally cultures were established in Earle s BSS containing 0.5% lactalbumin hydrolysate, 0.1% yeast extract, 0.1% polyvinylpyrrolidone and 2-5% FBS but they can be maintained successfully in Eagle s MEM (EBSS) with added 7.5% bovine serum and 2.5% FBS or Medium 199 supplemented with 5% FBS. Vero cells are adaptable to batch and continuous perfusion culture. 

Cells are cultured in Eagle s MEM containing Earle s BSS or Hank s BSS and with 10% FBS. The life span could be increased with different media formulations, e.g. CMRL 1969> MEM> BME. 

Earle s and Hanks balanced salt solution (BSS) 10 X concentrated, without bicarbonate and glucose... 

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