The effect of the hydrocarbon naphthalene on the morphology of the green flagellate Chlamydomonas angulosa

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Abstract
The morphological changes of C. angulosa, when incubated with a 50% saturated solution of the aromatic hydrocarbon naphthalene, were studied. Comparisons were made with the effects of crude oil. Observations under the light microscope reveal a totally inhibited motility, loss of flagella, an increase in the activity of the contractile vacuoles and the appearance of cytoplasmic granulation. The cells developed a surrounding transparent envelope. With EM, the following ultrastructural changes were revealed: the cell wall became partially thickened and a widened space developed between the cell wall and the plasmalemma; abnormal chloroplast lamellae developed, composed of numerous thylakoids; starch grains increased in number and in size; the osmiophilic granules of the stigma became a hollow core with peripheral structure and electron-dense material became heavily deposited inside the cytoplasmic vacuoles. This material stained deeply with Sudan black B, indicating its lipid nature. No recovery of cells was found during the 8 day incubation period with naphthalene, in contrast to recoveries noted with crude oil treatment. The lipid deposits in the vacuole also showed no indication of migration or reduction during this period.