Cultivation in a semi-defined medium of animal infective forms of Trypanosoma brucei, T. equiperdum, T. evansi, T. rhodesiense and T. gambiense.

A semi-defined medium for the cultivation of bloodstream forms of the African trypanosome brucei subgroup was developed. Out of 14 different strains tested, 10 could be cultured including Trypanosoma brucei, T. equiperdum, T. evansi, T. rhodesiense and T. gambiense. The presence of a reducing agent (2-mercaptoethanol or thioglycerol) was found to be essential for growth. The standard medium consisted of Hepes buffered minimum essential medium with Earle's salts supplemented with 0.2 mM 2-mercaptoethanol, 2 mM pyruvate and 10% inactivated serum either from rabbit (T. brucei, T. equiperdum, T. evansi and T. rhodesiense) or human (T. gambiense). Although a general medium could be defined for the long-term maintenance of trypanosome cultures, the initiation to culture nevertheless required particular conditions for the different strains. The cultured trypanosomes had all the characteristics of the in vivo bloodstream forms including: morphology, infectivity, antigenic variation and glucose metabolism.     

Leaf volatiles from Thymus vulgaris, T. serpyllum, T. praecox, T. pulegioides and T. x citriodorus (Labiatae)

Wound–emitted leaf volatiles in soe species of Thymus were analysed. Fresh shoots without flowers were used. The volatiles were isolated by adsorption on a porous polymer (Tenax GC). The emitted components were separated by a capillary gas chromatograph modified to give reproducible retention time values. The identifications are based on mass spectra and retention time values of reference compounds. The results indicate the mildness of the method used. This is one part of the methodological work of an investigation concerning the biochemical background of pest and disease resistance in plants. Attention is drawn to the urgent need in resistance breeding for a taxonomic survey of the intraspecific allelochemic multitude.