The healthy little brown bats roosting close to the bat
with white-nose syndrome risk infection with the fungus
The deadly fungus that causes white-nose syndrome is sweeping through North American bat populations, and little brown bats are adapting their behavior to avoid it. Although these bats typically clump together in large groups, they are now spreading out to roost separately, a change in behavior that may be helping the bat populations rebound. So what does a bat-killing fungus have to do with human prejudice? The bats’ trick of splitting up to survive contagion may also have led humans to divide into tribes and respond hostilely to members of different, potentially diseased groups.
In a post on Scientific American’s Guest Blog, biologist Rob Dunn writes about the link between infectious diseases and human prejudice.
Fruit body of a parasitic fungus, growing out of a dead ant.
An unlucky ant inhales a spore, the fungus begins to eat the ant from inside, and, in a particularly sinister twist, Ophiocordyceps hijacks the ant’s brain. The “zombie” ant is forced to leave its nest to climb up onto a tree, clamping its jaws into a leaf vein with abnormal force. A stalk sprouts from the now dead ant’s head. This stalk is fruiting body of the fungus, which will produce new spores that rain down onto the unlucky ants below.
Ophiocordyceps seems like a lean mean killing machine in that scenario, but the fungus itself is vulnerable—to another fungus it turns out. A new paper published in PloS ONE models the disease dynamics of Ophiocordyceps with respect to ants and a hyperparasitic fungi, which is the name for parasite whose host is also a parasite. Unfortunately, this hyperparasite is not of much help for the ant, as it only infects the Ophiocordyceps after the ant has died.
How a living material of cheese fungi sandwiched between plastic sheets works.
The crusty rind of cheeses like Camembert provide more than texture: they are miniature fortress walls, made of fungus, that protect the cheese’s creamy insides from bacterial invasions. Now, taking inspiration from this delicious snack, chemical engineers at ETH Zurich in Switzerland have shown that such a fungus can be enclosed in porous plastic and will digest spills, with implications for creating antibacterial surfaces from living material.
The team sandwiched a layer of Penicillium roqueforti—from, you guessed it, Roquefort cheese—between a plastic base and a top sheet of plastic with nanoscale pores that allowed gas and liquids to move through, but did not allow the fungus to spread. Then, they mimicked a kitchen spill by pouring sugary broth on the surface and watched as, over the course of two weeks, the captive fungus gradually consumed the entire spill, leaving the surface clean. As shown in the figure above, the fungi can go dormant when there is no food around, so if one had a countertop of such a material, you wouldn’t need to keep spilling sugar on it to keep the fungi happy. Read More
One of the finest visual treats of the year comes when the National Science Foundation and its partners reveal the winners of the International Science and Engineering Visualization Challenge, as they have this week in the journal Science. The illustration you see above is HIV. Created by Ivan Konstantinov and colleagues, the 3D model of the virus graced the cover of Nature Medicine last year.
The model contains 17 different viral and cellular proteins and the membrane incorporates 160 thousand lipid molecules, of 8 different types, in the same proportions as in an actual HIV particle. It denotes the parts encoded by the virus’s own genome in orange, while grey shades indicate structures taken into the virus when it interacts with a human cell. To create the visualisation, the team consulted over 100 articles on HIV from leading science journals and talked to experts in the field. [New Scientist]
The other winners, which you can check out at Science’s site, include the wide world of fungi, colliding quasars, and (my favorite) the hairs of a tomato seed, seen below.
The hairs secrete a mucus that appears as a clear membrane at the edge of the seed, according to photographer Robert Rock Belliveau, a retired pathologist. This mucus has several purposes: killing predators with a natural insecticide, preventing the seed from drying out, and anchoring the seed to the soil. [National Geographic]
If you’re in the mood to gawk at more neat visualizations of science, check out the recent DISCOVER galleries of the telescope to replace Hubble, amazing supercomputer simulations, or the most psychedelic images in science.
Images: Ivan Konstantinov, Yury Stefanov, Aleksander Kovalevsky, Yegor Voronin/Visual Science Company ; Robert Rock Belliveau
The continued onslaught by white nose syndrome against North America’s bats is one of the stories of the year—number 13, in fact, on DISCOVER’s Top 100 of 2010. But some help soon could be on the way in the form of Endangered Species Act protection. Earlier this month, a group of conservationists and scientists filed an emergency petition with the United States Fish and Wildlife Service to list the little brown bat under the act.
Emergency listing for a species does happen, but not very often, says Ann Froschauer, national white-nose syndrome communications leader for FWS. “Given the urgency of white-nose syndrome and recent information about predicted declines in little brown bat populations, the Service is committed to quickly reviewing scientific information, both published and provided by organizations such as these, in assessing the status of little brown bats and other bat species affected by WNS.” [Scientific American]
Listing the bats as endangered could force government action to protect them, including increased funding and the designation of critical habitat.
UPDATE: Fortune reports today that the lead researcher on this study, Jerry Bromenshenk, had financial ties to Bayer Crop Science—including a research grant—that were not disclosed. Bayer makes pesticides that some beekeepers and researchers have cited as a possible cause of colony collapse disorder, and Bromenshenk’s conclusions in this study could benefit the company. Bromenshenk says the money did not go to this project or influence its findings.
Viruses. Mites. Fungi. Genetically modified crops. Inbreeding because of industrial agriculture. They’ve all been floated as possible causes of colony collapse disorder (CCD), the mystery affliction that’s been wiping out honeybees, and by doing so threatening the agricultural industries that rely on those insects. Despite the flood of reports since 2006 about these suspects (and more absurd ones, like cellphone radiation disorienting the bees), the bee die-off continues without a clear explanation.
A study out this week in PLoS One points the finger in a new direction. What’s interesting about this explanation is its contention that there’s tandem foul play at work in CCD—two of the suggested culprits could be working together. But the mystery isn’t solved just yet.
For tiny spores, there’s no defeating gravity—unless they work together.
The pathogenic fungus Sclerotinia sclerotiorum travels from place to place by shooting its spores up in the air to be carried away, the same way many plants and fungi spread. A single spore, however, can barely get airborne before it falls back to the surface. A species isn’t going to spread far with that kind of flight time, but luckily, this fungus has a solution. It blasts its spores en masse, creating a wind current that helps them all drift away to new homes.
When we last covered little brown bats it was with big bad news: A study in Science suggested that white nose syndrome could kill enough of the bats to make them regionally extinct in many parts of the United States by 2020. This week, though, brought a glimmer of hope. Scientists at the New York State Department of Health led by Vishnu Chaturvedi say some anti-fungal drugs work against the mysterious fungus causing the bat die-off.
They tested six strains of the novel fungus against drugs already used to treat people and animals such as cats and dogs for ailments ranging from athlete’s foot to life-threatening infections. “We found that two major classes of antifungal drugs have very good activity” against the bat germ, Chaturvedi reported Sunday in Boston at a meeting of the American Society for Microbiology. The drugs include fluconazole, the most widely used antifungal drug, which is sold as Diflucan by Pfizer Inc. and in generic form. Four other drugs also seem highly effective, Chaturvedi said. [AP]
Here’s one that I didn’t touch on in DISCOVER’s creepy gallery of zombie animals controlled by mind-altering parasites: A parasitic fungus called Ophiocordyceps unilateralis that infects a plain old carpenter ant and takes over its brain, leading the ant to bite into the vein that runs down the center of a leaf on the underside. The ant dies shortly thereafter, but the fungus gains the nutrients it needs to grow this crazy stalk out of the ant’s body and release spores to create the next generation of ant-controlling fungi.
This cryptic cycle has been going on for at least 48 million years.
In a study forthcoming in Biology Letters, Harvard’s David Hughes argues that a fossilized leaf found in a fossil-rich part of Germany’s Rhine Rift Valley bears the scars of the ant’s trademark death bite. The ant bites down hard so the fungus will have a stable position when it grows a stalk out of the ant’s head. But even so, Hughes says, he doubted the mark would turn up in the fossil record—that is, until serendipity reared its random head: