Seedy but Speedy: Fungus Spews Spores at 55 Mph

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September 17, 2008

Seedy but Speedy: Fungus Spews Spores at 55 Mph

Finding could lead to new fungi-killer chemicals

Scientific American*

By nah F. Locke

http://www.sciam.com/article.cfm?id=fungus-spores-fast-speedy-mold

In a finding that could help control harmful fungus, researchers

have discovered a high-speed mechanism the germs use to project

their spores into the air. Scientists from Miami University (M.U.)

in Oxford, Ohio, and the College of Mount St. ph in Cincinnati

report in the journal PLoS ONE that fungi may be one of the fastest

land species, clocking speeds of up to 55 miles (88 kilometers) per

hour and producing accelerations 180,000 times greater than gravity.

Fungi are the most common crop pathogens in the world. Most are

fairly harmless to people, although like other allergens they

sometimes exacerbate allergies and asthma. But certain varieties

such as Stachybotrys chartarum, commonly referred to as black mold,

that thrive in damp places like basements may also infect the lungs

of people who have compromised immune systems or chronic bronchitis.

Biologists once believed that mild air currents were enough to

release fungi's spores, but are increasingly finding that molds

employ elaborate methods to spew their seeds away from the nest.

Using ultrahigh-speed video, the researchers calculated that some

fungi use their own natural water pressure like squirt guns to eject

their spores.

" The beauty of the mechanism was a great surprise, " says lead study

author Money, a fungus biologist at M.U. " We were totally

gobsmacked by these images. "

Money studied fungi that grow on cow patties and other herbivore

dung. These species play a critical role in the ecosystem by

breaking down waste to recycle its nutrients into the soil. The

fungi project their spores away from the resident dung because cows

will not eat near feces. By shooting them up to eight feet (2.5

meters) away, a grazing animal will be more inclined to eat them,

thereby spreading the fungal spawn via its own manure.

The research video camera shot 250,000 frames per second to capture

fungi spurting their spores into the air, trailing glistening liquid

behind them. The researchers used the video to clock the spores

speeding along at 55 mph.

The team also identified how several fungi build up water pressure

to power a spore launch. First, the fungi accumulate sugars and

other small molecules in their cells, which, in turn, brings in more

water. Targeting the first step of this process could be a key to

developing new fungicides.

" This [study] provides a critical insight into the lifestyle of a

fungus, " says Roberson, a fungus biologist at Arizona State

University's School of Life Sciences in Tempe, who called the

study " significant. "

Money is currently using the same methods to detail a different

launching method employed by a fungus group that includes black

mold. " By understanding the basic mechanism, " he says, " you might

find ways to remediate a mold-damaged home. "