Minimal essential medium (MEM) is a synthetic cell culture medium developed by Harry Eagle first published in 1959 in Science that can be used to maintain cells in tissue culture. It is based on six salts and glucose described in Earle's salts in 1943: calcium chloride, potassium chloride, magnesium sulfate, sodium chloride, sodium phosphate and sodium bicarbonate. The medium is further supplemented with thirteen essential amino acids, and eight vitamins: thiamine (vitamin B1), riboflavin (vitamin B2), nicotinamide (vitamin B3), pantothenic acid (vitamin B5), pyrodoxine (vitamin B6), folic acid (vitamin B9), choline, and myo-inositol (originally known as vitamin B8). Many variations of this medium have been developed, mostly adding additional vitamins, amino acids, and/or other nutrients.
Eagle developed his earlier "Basal Medium Eagle" (BME) in 1955–1957 on mouse L cells and human HeLa cells, with 13 essential amino acids and 9 vitamins added. BME contains biotin (vitamin B7), which Eagle later found to be superfluous. His 1959 "minimal essential medium" doubles the amount of many amino acids to "conform more closely to the protein composition of cultured human cells. This permits the cultures to be kept for somewhat longer periods without refeeding".
DMEM (Dulbecco's modified Eagle's medium) was originally suggested as Eagle's medium with a 'fourfold concentration of amino acids and vitamins' by Renato Dulbecco and G. Freeman published in 1959. The commercial versions of this medium have additional modifications, see an example in the table below.
α-MEM (minimal essential medium Eagle – alpha modification) is a medium based on MEM published in 1971 by Clifford P. Stanners and colleagues. It contains more non-essential amino acids, sodium pyruvate, and vitamins (ascorbic acid (vitamin C), biotin, and cyanocobalamin) compared with MEM. It can also come with lipoic acid and nucleosides.
Glasgow's MEM (Glasgow minimal essential medium) is yet another modification, prepared by Ian MacPherson and Michael Stoker.
Composition
One liter of each medium contains (in milligrams):
Medium BME MEM α-MEMa DMEM Glycine5030 L-alanine25 L-arginine hydrochloride2112612684 L-asparagine-H2O50 L-aspartic acid30 L-cysteine hydrochloride-H2O100 L-cystine 2HCl16313163 L-glutamic acid75 L-glutamine292292292584 L-histidine83142 L-histidine hydrochloride-H2O4242 L-isoleucine265252105 L-leucine265252105 L-lysine hydrochloride36.477373146 L-methionine7.5151530 L-phenylalanine16.5323266 L-proline40 L-serine2542 L-threonine24484895 L-tryptophan4101016 L-tyrosine disodium salt dihydrate265252104 L-valine23.5464694 Ascorbic acid50 Biotin10.1 Choline chloride1114 D-calcium pantothenate1114 Folic acid1114 Niacinamide1114 Pyridoxal hydrochloride1114 Riboflavin0.10.10.10.4 Thiamine hydrochloride1114 Vitamin B121.36 i-Inositol2227.2 Calcium chloride (CaCl2, anhyd.)200200200200Ferric nitrate (Fe(NO3)3·9H2O)0.1 Magnesium sulfate (MgSO4, anhyd.)97.6797.6797.6797.67 Potassium chloride (KCl)400400400400 Sodium bicarbonate (NaHCO3)2200220022003700 Sodium chloride (NaCl)6800680068006400 Sodium phosphate monobasic (NaH2PO4-H2O)140140140125 D-Glucose (dextrose)1000100010001000 Lipoic acid 0.2 Phenol red10101015 Sodium pyruvate 110110
See also RPMI 1640 (Roswell Park Memorial Institute medium), for lymph cells
References