Science Daily: Cryptococcus: Pathogenic Fungus Loves Your Brain Sugar

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This Is Your Brain on Cryptococcus: Pathogenic Fungus Loves Your Brain

Sugar

ScienceDaily (Apr. 6, 2010) — Highly dangerous Cryptococcus fungi love

sugar and will consume it anywhere because it helps them reproduce. In

particular, they thrive on a sugar called inositol which is abundant in the

human

brain and spinal cord.

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(http://mail.google.com/articles/f/fungus.htm)

To borrow inositol from a person's brain, the fungi have an expanded set of

genes that encode for sugar transporter molecules. While a typical fungus

has just two such genes, Cryptococcus have almost a dozen, according to

ph Heitman, M.D., Ph.D., chairman of the Duke Department of Molecular

Genetics and Microbiology.

" Inositol is abundant in the human brain and in the fluid that bathes it

(cerebral spinal fluid), which may be why this fungus has a predilection to

infect the brain and cause meningitis, " Heitman said. " It has the machinery

to efficiently move sugar molecules inside of its cells and thrive. "

The findings on Cryptococcus genes were published online this week in the

inaugural issue of mBio, a new open access microbiology journal.

This specialized brain attack likely occurred because these fungi adapted

to grow on plants in the wild, which also are abundant in inositol, said

lead author Chaoyang Xue, Ph.D., formerly a postdoctoral research associate in

the Heitman lab and now an assistant professor at the Public Health

Research Institute at the University of Medicine and Dentistry of New Jersey

(UMDNJ). " In fact, this pathogenic yeast has more inositol transporters than

all other fungi we have compared it to in the fungal kingdom, based on what

we know from genome research. "

The team of researchers discovered that inositol stimulates Cryptococcus to

sexually reproduce. " A connection between the high concentration of free

inositol and fungal infection in the human brain is suggested by our

studies, " Xue said. " Establishing such a connection could open up a new way to

control this deadly fungus. "

Cryptococcus' love for sugar may also be a fungal Achilles Heel, Heitman

said. " Now scientists may be able to target the fungi by developing ways to

put them on the fungal equivalent of an Atkin's low-carbohydrate diet so

they will stop multiplying. " He said researchers could use the new findings to

devise different types of strategies to block Cryptococcus infections.

These studies will be reported in the inaugural issue mBio, which will be

launched in May by the American Society of Microbiology as an online journal

that spans all areas of microbiology.

Other authors include Lydia Chen and Wenjun Li of the Duke Department of

Molecular Genetics and Microbiology; Tongbao Liu of the Public Health

Research Institute, University of Medicine and Dentistry of New Jersey; Iris

Liu

and Kronstrad of Laboratories, University of British

Columbia; and s Seyfang of the Department of Molecular Medicine at the

University of South Florida.

This work was supported by National Institute of Health/National Institute

of Allergy and Infectious Disease grants. This work was also supported by

the new Investigator institutional start-up fund from

UMDNJ._http://www.sciencedaily.com/releases/2010/04/100405152757.htm_

(http://www.sciencedaily.com/releases/2010/04/100405152757.htm)

Sharon Noonan Kramer