All posts by Chris Villalta

Amphibian skin bacteria shown to fight off Batrachochytrium dendrobatidis.

A year ago researchers at James Madison University discovered that, Pedobacter cryoconitis, a bacteria first found on the skin of red backed salamanders, was found to prevent the growth of the chytrid B. dendrobatidis, which is currently decimating frog populations.

(Mountain Yellow-Legged Frog from wikipedia)

The newest research on the subject is being presented this year at ASM by Brianna Lam who worked with other biologists from both San Francisco State University and JMU.

Lam’s research indicates that adding pedobacter to the skin of mountain yellow-legged frogs would lessen the effects of Batrachochytrium dendrobatidis (Bd), a lethal skin pathogen that is threatening remaining populations of the frogs in their native Sierra Nevada habitats.

Lam first conducted petri dish experiments that clearly showed the skin bacteria repelling the deadly fungus. She then tested pedobacter on live infected frogs, bathing some of them in a pedobacter solution. The frogs bathed in pedobacter solution lost less weight than those in a control group of infected frogs that were not inoculated.

In addition to the lab experiments, the JMU and SFSU researchers have studied the yellow-legged frogs in their natural habitats and discovered that some populations with the lethal skin disease survive while others go extinct. The populations that survived had significantly higher proportions of individuals with anti-Bd bacteria. The results strongly suggest that a threshold frequency of individuals need to have anti-Bd bacteria to allow a population to persist with Bd. (from Eureka alert)

The research above is really interesting and I am curious as to how the bacteria is actually killing the chytrid. The only other research I can think of where chytrids were being killed was a BBC news article that wrote about scientists bathing frogs in chloramphenicol.

Will a zygomycete help solve our energy woes?

I found the headline today, “Biofuels: Fungus Use Improves Corn-to-ethanol Process” and I was curious to find out what fungus they were talking about in the article. It turns out that researchers at Iowa State University found that Rhizopus microsporus is able to grow off part of the leftovers of ethanol production called thin stillage. The reason this is so exciting is explained below:


(Rhizopus sporangium, picture taking during PMB 110L @ UC Berkeley)

The fuel is recovered by distillation, but there are about six gallons of leftovers for every gallon of fuel that’s produced. Those leftovers, known as stillage, contain solids and other organic material. Most of the solids are removed by centrifugation and dried into distillers dried grains that are sold as livestock feed, primarily for cattle.
The remaining liquid, known as thin stillage, still contains some solids, a variety of organic compounds from corn and fermentation as well as enzymes. Because the compounds and solids can interfere with ethanol production, only about 50 percent of thin stillage can be recycled back into ethanol production. The rest is evaporated and blended with distillers dried grains to produce distillers dried grains with solubles.
The researchers added a fungus, Rhizopus microsporus, to the thin stillage and found it would feed and grow. The fungus removes about 80 percent of the organic material and all of the solids in the thin stillage, allowing the water and enzymes in the thin stillage to be recycled back into production.
The fungus can also be harvested. It’s a food-grade organism that’s rich in protein, certain essential amino acids and other nutrients. It can be dried and sold as a livestock feed supplement. Or it can be blended with distillers dried grains to boost its value as a livestock feed and make it more suitable for feeding hogs and chickens.

The idea of being more efficient by saving water and producing nutritious animal feed that can produce healthier animals that produce more meat is very interesting and worthwhile. But the article never mentions that many Rhizopus species are considered pathogens and R. microsporus when paired with Burkholderia rhizoxinia, a endosymbiont that produces rhizoxin, essentially becomes the pathogen responsible for rice seedling blight. Rhizopus also can cause serious mycoses in humans (The non squeamish can search for rhizopus mycoses on google).

I am curious if this Rhizopus has any endosymbionts that could be helping it grow on stillage or what other fungi that may not be potential pathogens might be out there that could also grow on the thin stillage.

Invasion of not so tasty truffles.

(Truffle picture from BBC.com)

The BBC (link) has an interesting article about a  Chinese Black truffle being found as an invasive species in Italy. The Italian’s and European truffle aficionados are worried that the Chinese Black Truffle will outcompete the Perigord Black truffle, which is supposed to be very tasty and the second most expensive truffle by weight, behind only the Piedmont White Truffle.

The scientific journal article (link) the BBC cites is present in the new phytologist and was authored by a lab from the “Dipartimento di Biologia Vegetale dell’Università di Torino. Looks like the Chinese truffle species could be a good invasive species model and also economically important.

Truffles are interesting its amazing people would pay so much for a mushroom, sadly I can’t say if one tastes better than the other since I have not had the chance to try of the truffles mentioned above.