User:Rachel Oakes- Malassezia Globosa
Domain; Phylum; Class; Order; Family [Others may be used. Use NCBI link to find]
Description and Significance
Malassezia globosa is typically found in human skin and is known to cause dandruff. M. globosa thrives in the human scalp since it requires lots of lipid as a carbon source, so sebum satisfies the fungus. Usually, the fungus looks like small islands, with a greenish appearance and separated groups of the microbe.  If it acts as dermatitis, it will appear as small white patchy flakes on the human scalp or small, light, discolored patches on the skin as tinea versicolor. Studying the chemistry and genome of M. Globosa is important to understand the stronger treatment for these fungal infections since M. Globosa is a common part of the skin flora. Malassezia globosa is also important because it is so common since it causes 50% of the world’s population to be affected by dermatitis and tinea versicolor.
The sequenced size of M. Globosa was 9 Mb. Twenty - seven percent of the genes were introns, which is a smaller percentage than most basidiomycete fungi. There are 9 chromosomes in the fungi and has 4,285 genes. The genome resembles the organization of a fungal polypeptide synthase. M. Globosa’s genome also codes for a lot of lipases, which shows the role of its’ genome to use fatty acids from other sources, with 6 phospholipases and 13 lipases encoded. This release of fatty acid occurs on the human scalp, where it typically resides. The genome when compared using DNA region sequences that revealed M. Globosa’s genome is most similar in sequence to a pathogen U. Maydis, despite the fact that U. Maydis prefers a plant leaf as its’ preferred host compared to the M. globosa’s human host. The genome is very small and is considered one of the smallest genomes of free-living fungi.
Cell Structure, Metabolism and Life Cycle
Through research published by PNAS, M. globosa is understood to partake in glycolysis, the glyoxylate cycle, pentose phosphate shunt, tricarboxylic acid cycle for metabolism. The fungus also synthesizes 20 Amino acids and 5 nucleic acids. It was previously believed that there was no possibility for globosa to perform metabolism properly because of the lack of a fatty acid synthase. Genome analysis released a synthase to exist, but have a different function, as a polyketide synthase. M. globosa was found to have two forms, an SMG1 and LIP1 form. Researchers studied the SMG1 model of the fungus and saw that two bulky hydrophobic residues are adjacent to catalytic and N- terminal of the lid. This could show that the hydrophobic residues cause steric hindrance with triacylglycerol binding for the lipase involved with M. globosa.  The genome is haploid since polymorphisms within the genome were rare. No sexual cycles have been found for M. globosa or any of its sister groups. It is believed, however, that the fungus completes its sexual cycle while growing on human skin, due to the fact that its close relative, U. maydis does just that when growing on a plant. A mating-type locus was discovered when the genome of Malassezia globosa was studied.
Ecology and Known Roles in Symbiosis
In what habitat(s) do you find this microbe? What roles (if known) does this microbe play in symbiosis with other organisms? What role or contribution does this microbe contribute to the environment.
List interesting facts about this microbe that would appeal to a general audience. Does the microbe play an important role in a process relevant to society?
[Sample reference] Bosch TCG, Guillemin K, McFall-Ngai M (2019) Evolutionary "Experiments" in Symbiosis: The Study of Model Animals Provides Insights into the Mechanisms Underlying the Diversity of Host-Microbe Interactions. BioEssays 41:1800256
This page was authored by Sara Joyce Willis as part of the 2020 UM Study USA led by Dr. Erik Hom at the University of Mississippi.