Studies of the Respiration of the Mycelium of the Fungus Myrothecium verrucaria

• Published in: American journal of botany Vol. 37; no. 5; pp. 379 - 387
• Main Authors: Darby, Richard T., Goddard, David R.
• Format: Journal Article
• Language: English
• Published: American Botanical Society 01-05-1950
• Subjects: Fermentation; Flasks; Fungal spores; Fungi; Mycelium; Oxygen; Phosphates; Respiration; Respiratory rate; Sugars
• ISSN: 0002-9122; 1537-2197
• DOI: 10.1002/j.1537-2197.1950.tb08184.x

Two types of mycelial preparations of M. verrucarla were used for respirometric studies: (a) macerates of mycelial mats grown in still culture, (b) pellets grown in shaker flasks. The latter was much more suitable material, since the blending caused fairly marked decreases in O2uptake. The rate of respiration varied markedly with the age of the culture, and the maximum QO2
around 100 was found with 20-30 hr. shaken cultures. By careful standardization of culture conditions reproducible results were obtained. The endogenous respiration of freshly harvested cultures was high, but it could be reduced by aeration in non-nutrient solutions. Addition of sugars to such aerated cultures caused an increase of O2uptake up to eight-fold; there is a marked oxidative assimilation with approximately 80 per cent of the sugar assimilated. The organism is strongly aerobic, no trace of fermentation was detected in pure N2, and the R.Q. was unity at I per cent O2. The respiration of the pellets showed an apparent maximum only at 40 per cent oxygen by volume. The respiration was essentially independent of pH between 3.and 8 and was markedly inhibited only at pH of 2 or 9.5.