Fig. 4From: Isolation and characterization of native Bacillus thuringiensis strains from Saudi Arabia with enhanced larvicidal toxicity against the mosquito vector Anopheles gambiae (s.l.)Comparisons among the native Bt63 and the reference strain Bt-H14 through biochemical profiling, scanning electron micrography and phase-contrast microscopy. In a, biochemical profiling with the API 50CH system shows that the Bt63 isolate produces acid from sucrose (indicated by arrow), whereas in b Bti-H14 is negative (arrow); all other 49 biochemical reactions were similar. In c and d, scanning electron micrograph (×10,000) of Bt63 reveals its larger Cry crystals (Cr) and smaller spores (Sp) than those Bti-H14. In e and f, the phase-contrast micrographs of sucrose gradient-separated Cry Crystals (Cr) from Bt63 appear, comparatively, larger than those of Bti-H14. Scale-bars: c, d, 1 μm; e, f, 10 μmBack to article page