D.G. Godfrey

Enzyme electrophoresis in characterizing the causative organism of Gambian trypanosomiasis

Trypanosoma (Trypanozoon) brucei includes three morphologically identical subspecies which are poorly defined by clinical behaviour; T. b. brucei does not infect man, whereas T. b. rhodesiense causes an acute, and T. b gambiense a chronic, disease. Thirty-three isolates of the complex, each of which had previously been identified on clinical or other criteria, were compared by the electrophoretic patterns of two trypanosomal enzymes, alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT). One particular ALAT pattern clearly segregated a group of human pathogens of which all except one were labelled T. b. gambiense. The exception was labelled T. b. rhodesiense, and in addition three putative T. b. gambiense isolates did not have this pattern; it is suggested that only one presents a serious anomaly. The T. b. gambiense group could also be subdivided by three ASAT patterns which coincided with known groupings based on serological criteria.

Isoenzymes of two aminotransferases among Trypanosoma vivax in Nigerian cattle.

During a period of three months, thin-layer starch-gel electrophoresis was used to examine the isoenzymes of alanine and asparate aminotransferases from samples of T. vivax collected from naturally infected Nigerian cattle. Experimentally infected cattle sheep and goats were also studied. Three patterns, termed Sets 1,2 and 3, differed in both enzymes. The stability of the enzyme patterns was generally confirmed in experimental animals. The results are discussed in relation to subspeciation in T. vivax.

Trypanosoma brucei brucei: polycations and the release of alanine aminotransferase.

Abstract Trypanosoma brucei brucei was exposed in vitro to the polycations protamine, poly- l -lysine and DEAE-dextran, and the effect was measured by the amount of l -alanine: 2-oxoglutarate aminotransferase (ALAT) (EC 2.6.15) released. Most was released after exposure to poly- l -lysine in a Tris buffer, less in a bicine buffer, and least in a phosphate buffer. The release of ALAT was reduced when the ionic strength of the buffer was increased. A high buffer osmolality caused a slight increase; marked increases occurred with increases in temperature, in polycation concentration and in molecular weight within any molecular series of polycation. Poly- l -lysine was the most active polycation. Although no difference was detected between the strains or between the antigenic variants of T.b.brucei , trypanosomes from heavily parasitemic rats (24-hr infection) were more susceptible to poly- l -lysine than those from lightly parasitemic (24-hr infection) rats. The polyanions, heparin and polygalacturonic acid, protected the organisms against the action of poly- l -lysine. The effect of the polycations is attributed, at least in part, to these positively charged substances binding to the negatively charged trypanosome surface. Much of the released ALAT was probably derived from lysed organisms, but some possibly from intact trypanosomes with altered permeabilities.