ULTRASTRUCTURE OF MOTILE CELLS OF HAEMATOCOCCUS PLUVIALIS GREEN ALGA AND TRIDIMENTIONAL RECONSTRUCTION OF THE FLAGELLAR APARATUS

DAMIANI, MARIA CECILIA; LEONARDI PATRICIA INES; CACERES EDUARDO

ROSARIO

Congreso; 10th Inter-American Congress of Electron Microscopy and 1st Congress of the Argetine Society of Microscopy.; 2009

Haematococcus pluvialis is a green alga cultivated massively to obtain the carotenoid pigment astaxanthin. Transmission and scanning electron microscopes were used to elucidate the ultrastructure of the motile cells. The atypical cell wall is composing by two strata, the outer one is fibrillar and the inner one is formed by adjacent vesicles rectangular in section. The endomembrane system is involved in the wall formation. The central nucleus is surrounded by numerous dictyosomes. A parietal lobed chloroplast contains several pyrenoids and one eyespot formed by one layer of lipid globules. Cytoplasmatic astaxanhin is produced by the activity of endoplasmic reticulum. Four contractile vacuoles lie adjacent to the plasma membrane. Neutral lipid droplets were detected using the fluorocrome Nile red with a confocal microscopy. Two flagella emerge from an apical papilla. The tridimentional reconstruction of the flagellar apparatus was obtained by means serial sections. Viewed from the anterior of the cell, it shows 180º rotational symmetry with a clockwise absolute orientation of its components. The cruciate microtubular root system has a 2:4/1:2:4/1 alternation pattern. A striated distal fiber connects the two basal bodies.  Electron-dense material cover the proximal end of each basal body. A large mitochondrium is related with the flagellar apparatus.