Fungal Word Friday

Lamella

One of the radiating plates on the underside of the cap on an agaric mushroom. Also referred to as a gill.

Lamella

Photo cred:
Wiki Commons contributor Amanita77

Surgery and Medicine Go Eye to Eye

Ah, the time old conflict of a surgeon and a medical doctor. Do we treat an ailment with drugs or scalpels? If we choose drugs, are we just culling the weak and leaving the strong pathogens? If we choose to operate, are we putting patients through excessive procedures and how do we know we have gotten everything?

One of the recent battles in this war was fought over moderate cases of Fusarium keratitis by researchers at the Chang Gung University College of Medicine (CCUCM).

 

Early Keratectomy in the Treatment of Moderate Fusarium Keratitis

 

Keratitis is an inflammation of the cornea. While it has a number of causes ranging from over exposure to light (such as during snow blindness) to herpes virus infection, Fusarium keratitis is dealing fungal infection. Actually, as the name implies it is dealing with fungi from the Fusarium genus. And keratitis caused by these fungi can present quite the treatment ordeal. For starters they are filamentous: which means they grow a nice cottony mycelial blanket in/ on the eye. Unfortunately by the time this is visible you have already moved past the initial stages of the infection. It takes up to a few weeks after the germ tube starts for full infiltration and inflammation to become apparent. Up to that point you just sit there with individual feathery hyphae, poking and prodding their way across your cornea.

Progress of Fusarium keratitis

With minor cases the simplest solution is just medical treatment, but as it becomes more advanced surgical intervention is often needed. But what about those moderate cases in the middle? The ones where it may go away with treatment, but then again maybe it won’t. That range of infection is the focus of the CCUCM teams study.

The researchers investigated 38 cases of moderate Fusarium keratitis between January 2004 and December 2010. Of those patients 13 got keratectomies within a week of entering the hospital and twenty were only treated medically.  Out of the patients, five of them didn’t have follow up records and were thus discarded from the research conclusions. There were no major differences between these two groups in regards to age, sex, or severity of eye infection; however it was noted that the medicated group did average a significantly worse baseline vision than the surgery group.

While reviewing all records the group contrasted costs, hospitalization days, disease duration, and perforation progress between the contrasting treatments. Eye photographs were documented weekly and any progress or negative response led to a reculture for Fusarium after a 24 hour break of topical antibiotics.
The results seem to be a straight up win for the surgeons. The group receiving keratectomies had a much shorter duration of the disease, with an average of 29 days vs. 54 days; and of those days the surgery group was only in the hospital 11 days, compared to the medical groups average 31 day stay. Of course the longer stay for those receiving medication also caused a severe jump in cost, having a range centering around 20,000 New Taiwan Dollars higher. And addressing the largest physical end comparison, the degree of corneal perforation following the procedures: in this study group 20% of those treated with medicine only developed perforations, while absolutely none of the patients that went through surgery did. The Scalpel jockeys seem to have sliced out a victory here.

That being said the research team did acknowledge that this was just a retrospective study and with treatments based on the preferences of the physicians, which allowed for potential biases.

Now for the real purpose of this post:


Awesome researchers:
Hsin-Chiung Lin, Ja-Liang Lin, Dan-Tzu Lin-Tan, Hui-Kang Ma, & Hung-Chi Chen (2012). Early Keratectomy in the Treatment of Moderate Fusarium Keratitis PLOS One DOI: 10.1371/journal.pone.0042126

Fungal Word Friday

Ascocarp

The fruiting body of Ascomycetes, bearing the asci and ascospores.

Multiple shaped Ascocarps of Xylaria polymorpha.

Photo Courtesy of Jim Deacon, The University of Edinburg

Tuesday Treat

It is kind of a busy week for the next few day so I don't see a chance to get to read any journals until at least Thursday. Until then here are some time lapse mushroom videos:

Fungi Can Give Bees Diarrhea!!

There has been a well documented decline of honey bee colonies across the globe. One of the prime causative agents has been determined to be the fungal genus Nosema. The infections by these fungi are generally passed through a fecal oral pathway (You read that right, fecal-oral). And in order to facilitate their spread the members of this genus often induce increased defecation. I want to point out that this means they give bees diarrhea, I never even knew bees could get diarrhea! The concept never even crossed my mind... Anyways, one member of the Nosema genus, N. ceranae, in fact does not have increased defecation as a symptom; which begs the question, how does it spread? A study by Michael L. Smith of Wageningen University seeks to answer exactly that question.

Bee Squirts

His basic premise is that since Nosema ceranae does not induce pooping, logically it must be spread via another pathway. And with that in mind he focuses this study on the potential spreading of spores through oral transfers of food.

The Honey Bee Parasite Nosema ceranae: Transmissible via Food Exchange?

To test the hypothesis he set up a series of hoarding cages with varying degrees of separation between infected older bees and non-infected young bees. This way the older bees would feed the younger if able and potentially spread spores of N. ceranae to them. While the test cannot rule out any fecal transmission, (the spores are still present there, the fungus just doesn't give the bees the runs) it does cut down on exposure via that pathway. The three degrees of cage separation were as follows: A single screen between the cages would allow for the transfer of food but not allow intermingling, a dual screen would keep the older bees from even getting a chance to feed the younger ones, and a control of isolated young bees would, well, act as a control for natural exposure.

First, to ensure infection, the bees destined to be used as "Older bees" were taken from their hives and marked. They were then coated with a sucrose solution laced with N. ceranae spores. As they cleaned themselves they ingested the spores leading to infection. These bees were then allowed to incubate their new parasite for 12 days before being collected and used in the first of three trials. A second set of trials was conducted with the older bees not being artificially infected but picked to represent a natural spread in colony.

The "Younger bees" for the test were taken directly from combs using an aspirator quickly after emergence and isolated until test runs.

For the testing the cages were placed next to each other in the aforementioned set ups for 4 days. In all sets the older bees were fed a sucrose solution and in the case where young would not be reachable they too were fed the same type solution. However; in the young bees directly adjacent to the old bee cage, no food was provided on days 2-4. This forced them to receive food via feeding from the older bees. Mortality of the young bees during this time was no different than the rest of treatment times.

After the exposure was complete the bees were then allowed to incubate for 10 days before being dissected to detect infection. For the dissection each bee had its midgut extracted and opened under a microscope. Then spore presence was observed by looking at 25 field views for each sample. Due to the high colonization of infected bees only bees counted with  >100's of spores were counted as infected.

And the infection rates showed very strong correlation with the single screen exposure. In fact, while there was not much notable difference between the dual screen and the control group, the single screen bees showed a 13 times higher rate of infected young bees.

The researcher does take special time to note that while precautions to prevent defecation spread were taken, and that no feces were observed on the separation screen, there is still potential that the fecal-oral pathway could still potentially be a factor in spread. But despite that the study gives the first experimental support to the hypothesis that N. ceranae is spread through oral-oral exchange.



Awesome researcher:
Michael L. Smith (2012). The Honey Bee Parasite Nosema ceranae: Transmissible via Food Exchange? PLoS One DOI: 10.1371/journal.pone.0043319

Photo/Gif cred:
Wiki Commons Contributer Athen_Ananda

Foreign Spore Germination: Science Storiented

Wow, there is more action going on about fungi in other places than here this week.
Today I bring you a story from another contributor to Research Blogging. Her name is evidentally Melissa, and on her blog Science Storiented yesterday she wrote a semi-follow up piece to a previous post she wrote about Ophiocordyceps. Don't worry her post has a link to the original.

Anyways, the post is about a PLoS One entry regarding the coevolution between the fungi and its doomed ant host.

Without further ado:
Castrating the Zombie Ant

Fungal Word Friday

Falcate

Falcate means having a curved or sickle shape. In fungi this is generally referring to spore or conidia shape.

Falcate macroconidia of Fusarium verticilloides

Phot Cred:
K. Nishimura of Chiba University Research Center for Pathogenic Fungi and Microbial Toxicoses.