* Compositions might vary slightly as some formulations do not specify the salt or degree of hydration.

** HMI-9 is based on IMDM (GIBCO catalogue number 12440). Since January 2007 we routinely omitted Thymidine (previously 39 mg/liter: 0.16 mM). Since August 2009, we routinely added 10 mg/liter each of Uracil and Cytosine because we are using some variants that cannot make pyrimidines. We took out the thymidine because (a) pyrimidines are not required for tryp growth in culture (but low serum concentrations might reduce growth in mice) (b) its omission makes the cells more sensitive to GCV, with which T competes (c) the amount in HMI-9 seems unnecessarily high, although T.brucei does not have a thymidine transporter (mea culpa, the amount of uracil and cytosine are possibly also unnecessarily high as they are actively imported, and cytosine is probably redundant) and other widely used media for Tb culture do not contain it. My enquiries, especially among trypanosome people working on purine and pyrimidine metabolism, have failed to identify why Hirumi originally included it and have not identified any reason to include it (for information on pyrimidine uptake see Gudin S, Quashie NB, Candlish D, Al-Salabi MI, Jarvis SM, Ranford-Cartwright LC & de Koning HP (2006) Trypanosoma brucei: a survey of pyrimidine transport activities. Exp Parasitol 114:118-25. DOI PMID).

*** MEM is GIBCO MEM with non-essential amino acids catalogue number 10370021. There are some variations (enhancements) of MEM in the catalogue.

**** Duszenko's medium for BF is as published in 1990 (MBP 40, 13-22) with modifications in 1995 (MBP 70, 157-166). The inclusion of myristic acid is probably not essential as it is not in other media. When supplemented with proline (600 mg/l), hemin ( 7.5 mg/l), citrate (882 mg/l) and cis-aconitate (522 mg/l) it was used to differentiate BF to PF, which could be maintained in the same medium but without citrate, cis-aconitate, cysteine, bathocuproine, or supplemental (to MEM) glucose, and with 10% serum. In principal using almost the same medium for BF and PF should simplify laboratory management, but I do not know if MEM gives the same high yield of PF as do Cunningham's and SDM-79.

**** The original DTM was further modified (to the composition shown here) by adding glycerol (in place of glucose), heme, 15% fetal bovine serum, 0.2 mM 2–mercaptoethanol, and extra proline, glutamate, glutamine. There is an error in the published (Ziegelbauer K, Quinten M, Schwarz H, Pearson TW, Overath P. Synchronous differentiation of Trypanosoma brucei from bloodstream to procyclic forms in vitro. Eur J Biochem 1990;192:373-8) formulation: glycine is stated where glycerol was intended. Vassella and Boshart further modified DTM by adding 28.2 mg/l bathocuproine and 182 mg/l cysteine (Vassella E, Boshart M. High molecular mass agarose matrix supports growth of bloodstream forms of pleomorphic Trypanosoma brucei strains in axenic culture. Mol Biochem Parasitol 1996;82:91-105). You might want to consider doing this and adding the same two ingredients to SDM79, or any other medium you use.

***** Some people have asked if I know why Taurine is present (and at high concentration) in SDM79 and Cunningham’s medium. I have no idea, but I am sure it is unnecessary. Taurine, in which the sulfur is oxidized, can be a product of cysteine degradation but does not seem to be a useful source of anything.

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