Fig. 2. Immunogold-labeled CDP II in a near median longitudinal section of hyphal apex of Allomyces arbuscula seen in an electron micrograph. (A) General view showing an apico-basal gradient of the enzyme. 1-5 correspond to the zones used for quantification of labels (see Table 2). (B) Higher magnification of the proximal tip region corresponding to zone 1. (C) Higher magnification of the distal region corresponding to zone 3 rich in mitochondria. (D) Higher magnification of zone 4 with nuclei. m, mitochondria; v, vacuole; n, nucleus.