Effect of myoinositol and zinc on sporangiosporeyeast transformation of Mucor circinelloides Tieghe

Abstract

Environmental factors influence mould-yeast interconversion. Such factors may trigger changes at the cellular level. Yeastlike cells induced from sporangiospores of Mucor species consist of central globose
mothercell, which produce multiple buds by blastic action. This study examines the effect of synthetic broth on sporangiospores of M. circinelloides. Sporangiospores of M. circinelloides converted to
determinate thallic subtypes including enterothallic- holothallic- and holoblastic conidia, as well as terminal budding yeast cells in synthetic broth treatments with zinc and myoinositol (myo) supplementations. In a study monitored at 24 h intervals, profiling gave 2-phase expression in some treatments and this was influenced by the presence of thallic forms. However, sigmoid pattern was obtained in control broth as well as in 0.25 mM Zn2+ and 1.0 – 3.0 mM myo treatments. Such treatments
enhanced growth by 32.95, 65.07 and 63.82%, respectively, over control mean growth. Proliferating yeast cells induced from sporangiospores of M. circinelloides transformed through several transient morphologies in a sequential manner, protoplast being the cross over form. Zinc and myo
supplementation enhanced yeast induction. It was strongly suggested that they acted as second messengers in signal transduction and consequent yeast induction. Whereas thallic subtypes were present, subsequent transformation of their cytosolic contents, following thallic cell wall rupture,
followed the same pattern of lateral morphogenetic transformation