FIG. 4.
LdGFPK7 axenic amastigotes show a severe growth defect. (A) Growth curve of axenic amastigotes. Growth of L. donovani pXG (•)- and pLEXSY (○)-transfected control and transgenic LdGFPK7 (⋄), LdGFPK7_TXY (▿), LdGFPK7_K (▵), and pLEXSY-LmaMPK7 (♦) promastigotes (pro) and axenic amastigotes (ama) was assessed microscopically by cell counting. The averages and standard deviations for triplicate determinations are shown. The data are representative of two independent experiments. (B and C) Determination of generation time. Logarithmically growing L. donovani axenic amastigotes of mock-transfected control (•) and transgenic LdGFPK7 (⋄) and LdGFPK10 (□) cells were inoculated into promastigote culture medium at pH 7.4 and at 26°C, and growth was determined microscopically by cell counting (B). The generation time (C) was calculated based on the number of generations (n) during logarithmic growth using the formula n = (logb − logB)/log2, with b being the number of cells at the end of a 24-h time interval and B being the number of cells at the beginning of the 24-h time interval.