Structure of the flagellar apparatus of the bacterivorous flagellate Histiona aroides Pascher, 1943 (Jakobida, Excavata)

Abstract

The structure of the flagellar apparatus of excavate flagellate Histiona aroides has been studied. Two naked flagella emerge from the bottom of ventral groove. The proximal part of the kinetosome has an osmiophilic cone. The posterior short flagellum bears a wide fold, which directs to the cell and contains striated material. The wide dorsal microtubular band starts close by the kinetosome of the anterior flagellum, the left and right bands of the band are divided in turn into two bands, and a single microtubule begins nearby the kinetosome of the posterior flagellum. Amorphous and striated fibrils accompany these bands. The left external band and a multilayer structure (band C) penetrate into the epipodium. The microtubular bands reinforce the bottom of the ventral groove and the external margin of the velum. In addition, the vesicular nucleus, extrusomes, contractile vacuole, and mitochondria with tubular cristae are visible on the cell sections. The similarity of H. aroides with representatives of the Jakobida family and other Excavata is discussed.