This week has rapidly turned into my craziest week yet as a graduate student. I'm absolutely overwhelmed. I'm to the point where I'm looking at my schedule for this week and wondering how the heck I'm supposed to do everything I'm supposed to do and be everywhere I'm supposed to be.
Between now and a week from Thursday, my time is essentially non-existent. After that, I plan on drinking heavily. Expect a drunken entry from me on the night of March 27 and not too much else between now and then unless something so incredibly interesting happens that I can't keep from writing about it. A plague, a nuclear explosion, or my decision to elope with Carmen Electra all might fill the bill on that score.
I've been doing a good deal of research on Cordyceps these last few days and what I'm learning is utterly fascinating. I have no time to write about all of it here, though, because I have to write a review of it all. What I wouldn't give for a psychic link to Joey Spatafora right now...
Being that today is the day when everybody is supposed to be a little bit Irish, it's a good day to remember how an organism that was until fairly recently classified as a fungus once changed Ireland, America and the world. I'm talking about Phytophthora infestans which, in fairness, isn't actually a fungus but an oomycete. Oomycetes, unlike fungi, don't have a chitinous cell wall and there are some other differences as well. Still, just as non-Irish people are today a little bit Irish, let's play along and say that oomycetes are a little like fungi.
Phytophthora infestans is the pathogen that caused the Irish Potato Famine of the 1840's that led to a wave of Irish migration to the United States. Many Irish-Americans can trace their ancestry back to an emigrant who left Ireland precisely because of the blight which, in turn, caused the collapse of not only the Irish economy but the British as well due to some very ill-advised speculation in grain futures. What those emigrants didn't know was that they were actually traveling back along the path by which P. infestans had gotten to Ireland in the first place. The population of the organism that caused the blight was native to America; it had already triggered the destruction of potato crops throughout the eastern US. From here, it traveled aboard a shipment of potatoes to Belgium and proceeded to demolish potato crops in that country and the Netherlands before finding its way to Ireland and triggering greatest wave of emigration from that country in all of its history.
For those who would like to read more about the specifics of how the Blight reached Ireland, today's New York Times is running a column entitled "The Fungus That Conquered Europe" (warning: registration is necessary to read the piece).
Of course, Phytopthora is a genus still very much with us. In recent years, close relatives of the potato famine pathogen have also damaged citrus crops in Florida with root and crown rots and are also responsible for sudden oak death and, to a lesser extent, are pathogens of a great number of vegetable crops. There are other parallels in the modern world to the Irish famine of the 1840's, too. As I've noted previously, the Ug99 strain of Puccinia graminis poses a major threat to world wheat crops and the rice blast fungus, Magnaporthe grisea, is a major pathogen with enough genetic variability around the world to pose an ever-looming threat as well.
Despite my nom d'blog, I'm not actually Irish — not even a little bit. Considering how much something like a fungus affected Ireland less than two centuries ago and how much that something changed the face of America forever, too, it's a good day for a bit of mycological reflection. For most of us, fungi aren't something we give much thought. Until they affect us by taking food off our tables or eating through the walls of our homes, fungal pathogens really don't get much opportunity to escape into conscious consideration. They could at any moment, though, change our lives forever. They've certainly done so before.
St. Patrick may have driven the snakes out of Ireland according to legend, but he doesn't seem to have been very good against Phytophthora. Still while you're hoisting a green beer at O'Malley's Pub today, keep in mind that a few errant cells from the right fungus can do a lot more than ferment what's in your mug; they can also foment massive changes in the course of human history.
Forgive the rather clumsy title of this entry. I'm taking a break from reading through a pile of papers on research into the evolution and symbiology of Cordyceps and just finished reading a paper that made me stop and go "Hmmmmm."
It's the second of Nikoh and Fukatsu's papers I've read and it incorporates findings from the previous study on Cordyceps. I don't have time to get into a lot of detail about the papers right now; suffice to say that both papers represent some truly meticulous work with results that go a long way in resolving the phylogeny of a rather enigmatic (and, as I've been told, slightly gruesome) group of ascomycetous fungi.
The part that made me stop and think, though, is found in the discussion section of the cited paper, on page 1639:
...Are there any causal relationships between upkeep of the introns and endosymbiotic/parasitic lifestyles? Although speculative, we suggest that the slow-growing nature of symbionts/parasites might be responsible. It is expected that the more group I introns rDNAs carry, the less efficient synthesis of rRNAs becomes. Because the ribosome is a copious cellular component essential for protein synthesis, multiple group I introns in rDNAs may result in reduced cell growth and division. If so, heavily inserted rDNAs may have a negative fitness effect on most free-living organisms in which the ability to grow rapidly under favorable conditions is essential for their survival and reproduction. On the other hand, the growth rate of endosymbionts/parasites must be suppressed under a strict control to cope with limited space inside the host body, to ensure survival of the host (at least for a while), to efficiently utilize resources from the host, to synchronize their life cycle parameters with those of the host, etc. (Tanada and Kaya 1993). Therefore, it is expected that the disadvantages due to heavily inserted rDNAs might be relaxed in slow-growing endosymbionts/parasites.
I find that a rather compelling hypothesis. In fact, one of the key issues for the success of Cordyceps populations parasitic upon arthropods is impeccable timing. Many of them are fine-tuned to produce stromata just as their host enters their pupal stage (cf. C. heteropoda on cicada nymphs or C. militaris on silkworms, etc.) I've always thought of selfish genes as being deleterious in terms of fitness, but in the case of endoparastites like Cordyceps, perhaps they're part of an overall system that has helped the fungi adjust their own growth to that of the host, having evolved through a series of introgressions and selection. That there are so many such introns in the rRNA sequences in this genus (as many as 69 in one species) is rather telling, I think. Also telling is the fact that these introns are capable of "jumping" in the genome but maintain a consistent position in the extant populations. Taken together, there almost has to be some kind of benefit here. This is some powerful evidence for Cordyceps evolution; that synteny is so highly maintained and polymorphism relatively low in flanking sequences and that transposition of the introns themselves hasn't been found speaks volumes.
Of course, Cordyceps are just plain cool — and a bit gruesome — for other reasons as well. They're related to the fungus from which we humans have managed to derive LSD, for one thing. That makes it all the more interesting that some of these fungi, such as the C. unilateralis in the video below, appear to change the behavior of their hosts — and then grow out of their heads! Check it out:
Aren't you glad you're not a bullet ant right about now?
While the phrase "meat sabers" may seem like a euphemism, it isn't and this update isn't about what you might have thought, you filthy person you. In this case, two men actually beat each other with meat. They wailed on each other with pork. Errrr... maybe I should just go ahead and link to the article now.
A prosciutto-wielding meat thief in Gloucester met his match when a restaurant owner fought off the assault by slamming the thief's face with a ham.
Joe Scola of Scola's Place heard a noise in his restaurant Wednesday, then saw a man fleeing with his arms full of meat from Scola's freezer.
Scola caught up, and started taking the meat back.
That's when the man raised a five pound log of frozen prosciutto over his head, presumably to whack Scola.
Luckily, Scola had his own frozen pig product on hand.
He tells the Gloucester Daily Times that he slammed the ham in the man's face, leaving a gash. The thief was so stunned, he dropped the meat and ran.
Police searched the area, but couldn't find the suspect.
I wish I was a good enough artist or video editor to do a mash-up of this story with a scene from Star Wars. Maybe I could put Yoda in the background as Darth Maul and Obi Wan Kenobi attack each other with their respective meat-sticks. Someone somewhere needs to do it.
One thing for sure; if you see Joe Scola coming at you with meat in his hand, you'd better start running. I know I would.
NOTE 1: Look, it's six AM and I have blogger's block because I'm supposed to be doing some writing that's going to be graded, so this is the best I could do for the moment.
NOTE 2: I attempted to find an illustration to go with this entry, but have you ever seen the results you get when you plug the words "meat saber" or "meat weapon" into Google images?
This blog is about whatever I'm pondering at the moment that I write in it. That may include anything at all. Mundane bits from my personal life, politics, science, fungi, genetics, media, dirty jokes, you name it. You're looking at the inside of my head when you're looking at this blog. Please don't litter and wipe your feet before entering. Thank you.
