DNA of dandruff-causing fungus decoded

12 November, 2007

Scientists claim that they have decoded the complete DNA (deoxyribonucleic acid) of a natural fungus that causes dandruff.

The research was conducted for Proctor and Gamble, a multinational corporation based in Cincinnati, Ohio, the United States, that manufactures a wide range of consumer goods.

The findings, say the researchers, could be a breakthrough that may lead to the elimination of the problem of the flaky skin condition called dandruff.

The study appears in the journal Proceedings of the National Academy of Sciences, published in the United States.

Dr Thomas Dawson, who led the five-year study, says the work by his team may pave the way for more effective shampoos, lotions, and medicines to provide people relief from the problem of dandruff.

Nearly all skin conditions, the study says, are associated with the yeast called malassezia globosa, which lives on human skin. The fungus, by feeding off natural oils in the skin and by releasing a toxic byproduct that can irritate the scalp, causes itchiness and clumps of dead skin that are noticeable on hair and clothes.

Medicated shampoos that are currently available to tackle the fungal infections are not totally reliable.

The fungus – which feeds on hair and sebum that protects skin – breaks down sebum with enzymes called lipases. Oleic acid, a byproduct of the process, penetrates the scalp and triggers the production of new skin cells. The old cells that flake off form dandruff.

The fungus is capable of excreting over 50 different enzymes that help digest and break down compounds in the hair and scalp.

It has been estimated that the fungus malassezia globosa grows on the skin of between 50% and 90% of the population. Besides dandruff, the fungus causes several other skin diseases.

Five years ago, researchers had found that malassezia globosa was associated with the dandruff condition. The genome for the dandruff yeast has 4,285 genes written in 9 million chemical ‘letters’ of DNA – which is minute compared to that for humans.

In the study, the researchers grew 10 litres of the yeast malassezia globosa in a tank, froze it in liquid nitrogen before extracting its DNA, and then crushed it into fragments. The DNA sequences of the pieces were fed into a powerful computer.

Dr Thomas Dawson wrote in Proceedings of the National Academy of Sciences, “A complete genomic sequencing of a malassezia genome opens tremendous opportunities for researchers to understand the interactions of fungi and humans. It is amazing that the understanding of the genetic makeup of a microscopic organism can have broad implications ranging from human health to agricultural science.”

“The malassezia genome genome sequence,” he added, “also revealed the presence of mating-type genes, providing an indication that the fungus may be capable of sex.”