Animals 2 Cholesterol 2 Ciliophora 2 Culture Media 2 Microsomes 2 Oxidoreductases 2 Oxidoreductases Acting on CH-CH Group Donors 2 Protozoa 2 Tetrahymena thermophila 2 adenosine triphosphate 2 animal 2 article 2 biotechnology 2 biotransformation 2 chemical reaction kinetics 2 cholesterol 2 culture medium 2 dairy industry 2 delta 7 cholesterol desaturase 2 enzyme activity 2 enzyme isolation 2 enzymology 2 growth, development and aging 2 isolation and purification 2 lathosterol delta 5 dehydrogenase 2 lathosterol delta-5-dehydrogenase 2 metabolism 2 microsome 2 nicotinamide adenine dinucleotide 2 nicotinamide adenine dinucleotide phosphate 2