Mucor dimorphism

Abstract

Mucor dimorphism has interested microbiologists since the time of Pasteur. When deprived of oxygen, these fungi grow as spherical, multipolar budding yeasts. In the presence of oxygen, they propagate as branching coenocytic hyphae. The ease with which these morphologies can be manipulated in the laboratory, the diverse array of morphopoietic agents available, and the alternative developmental fates that can be elicited from a single cell type (the sporangiospore) make Mucor spp. a highly propitious system in which to study eukaryotic cellular morphogenesis. The composition and organization of the cell wall differ greatly in Mucor yeasts and hyphae. The deposition of new wall polymers is isodiametric in yeasts and apically polarized in hyphae. Current research has focused on the identity and control of enzymes participating in wall synthesis. An understanding of how the chitosome interacts with appropriate effectors, specific enzymes, and the plasma membrane to assemble chitin-chitosan microfibrils and to deposit them at the proper sites on the cell exterior will be critical to elucidating dimorphism. Several biochemical and physiological parameters have been reported to fluctuate in a manner that correlates with Mucor morphogenesis. The literature describing these has been reviewed critically with the intent of distinguishing between causal and casual connections. The advancement of molecular genetics has afforded powerful new tools that researchers have begun to exploit in the study of Mucor dimorphism. Several genes, some encoding products known to correlate with development in Mucor spp. or other fungi, have been cloned, sequenced, and examined for transcriptional activity during morphogenesis. Most have appeared in multiple copies displaying independent transcriptional control. Selective translation of stored mRNA molecules occurs during sporangiospore germination. Many other correlates of Mucor morphogenesis, presently described but not yet explained, should prove amenable to analysis by the emerging molecular technology.

Upcycling of Whey Permeate through Yeast- and Mold-Driven Fermentations under Anoxic and Oxic Conditions

“…Mucor spp. have been shown to utilize lactose, and are considered spoilage organisms in dairy facilities [16,19,25]. Research suggests that lactose utilization and enzyme production in M. circinelloides and M. miehei can be affected by temperature and pH [26,27].…”

The Good, the Bad, and the Ugly: Tales of Mold-Ripened Cheese

“…Mucor is ubiquitous in the environment and, because of its proteolytic and saccharolytic activities, is responsible for decomposing fruit, meat, and bakery products (184,185). Though not a food-borne pathogen, Mucor can cause mucormycosis, an infection of the sinuses, brain, or lungs to which immunocompromised populations are most vulnerable (186).…”

DNA Methylation on N6-Adenine Regulates the Hyphal Development during Dimorphism in the Early-Diverging Fungus Mucor lusitanicus

“…The growing development of new molecular and genetic strategies to manipulate the M. lusitanicus genome has enabled the discovery of diverse virulence processes important for establishing infection, such as iron assimilation, dimorphism, and the RNA interference mechanism (RNAi) [ 9 , 10 ]. The dimorphism of some Mucorales species consists of the ability to change the growth form between yeast and hyphae, a process regulated by environmental conditions [ 10 , 11 ]. In aerobic conditions, M. lusitanicus exhibits filamentous growth, while in an anaerobic environment, it grows exclusively as yeast [ 12 ].…”