General biology
tsmith | February 9, 2007What's killing honey bees?
Something is wiping out honey bees across North America and a team of researchers is rushing to find out what it is.
What's being called Colony Collapse Disorder (CCD) has now been seen in Pennsylvania, North Carolina, Florida, Georgia and way out in California. Some bee keepers have lost up to 80 percent of their colonies to the mysterious disorder.
Now, I'm admittedly not much of a bee fan. Several of my relatives are highly allergic, and I've only been stung once and hope I'll be fine if it happens again, but they do kind of make me nervous when I see them…
tsmith | February 8, 2007So, I left off on Tuesday noting two things about our normal flora: 1) that in the big picture, we know hardly anything about them; and 2) that one reason we know so little about them is because we've never grown many of them in a laboratory setting--that is, we've never cultured them using our typical tools of the trade.
What's one way to remedy this? Eliminate the need for culture, and take some cues from the microbial ecologists. More on this below.
I've mentioned the term "metagenomics" previously on this blog (see the stories about it here and here). Using this technique,…
tsmith | February 6, 2007 I mentioned in the Introduction to Microbiology and Infectious Disease that many people don't understand the difference between a commensal and a pathogenic organism. I also mentioned that I'd try to write something about microbial ecology. Since I just gave a lecture yesterday on normal human flora in health and disease, now seems as good a time as any to combine these two and discuss just what it means when microbiologists refer to "normal flora" or "commensal organisms," and to talk about the microbial ecology of the human body in a series of posts on this topic.
First, though, a…
tsmith | February 2, 2007Introduction to Microbiology and Infectious Disease
You and your normal flora, Part I
You and your normal flora, Part II
tsmith | January 31, 2007I suppose everyone has someone who they consider an embarrassment to their alma mater. I can probably think of a dozen just off the top of my head regarding my undergraduate institution (including a number of politicians who shall remain nameless). However, one who really sticks in my craw is the infamous Jonathan Wells of the Discovery Institute, who also happens to be a Yale alum (Divinity school--small comfort that it wasn't Yale College, at least).
So, Wells has been back polluting Yale lately, via the Opinion pages of the student newspaper, the Yale Daily News. Predictably, Wells…
tsmith | January 26, 2007 Speaking of microbiology basics, along comes an article in the San Diego Union-Tribune about the petri dish, a staple of microbiology labs everywhere:
Before 1877, scientists exploring the nature and mechanics of microscopic life had a real problem. Bacteria used for study were typically cultured or grown in bottles or bowls of broth. Koch greatly improved the situation by developing ways to grow microbes in gel, which allowed researchers to separate and investigate individual types of bacteria.
But practical problems remained. It was hard to manipulate bacterial colonies through the small…
tsmith | January 25, 2007Like most fields, microbiology is one filled with jargon. Many laymen don't even realize the differences between a bacterium and a virus, much less the smaller differences between, for example, a pathogenic versus a commensal organism. So, while I haven't decided yet exactly what I might write about in future posts, I thought I'd begin with a very general microbiology primer to get everyone up to speed on the basics of the microbial word.
To begin with, in the "well, duh" category, microbiology is the study of very tiny life. Initially, those studied were mainly disease-causing organisms;…
tsmith | January 10, 2007 When it comes to hemorrhagic fevers, Ebola and Marburg tend to get the lions' share of the press. Both are highly fatal, both can cause people to die in excruciating ways, and both have come to represent somewhat our fear of and fascination with emerging exotic diseases. However, as I've pointed out previously, as far as actual fatalities--or even illnesses go--both viruses are small potatoes. Other viruses that can also have hemorrhagic manifestations--including dengue and yellow fever--are much more common. One of these other viruses that frequently causes hemorrhagic fever is Rift…
tsmith | January 3, 2007It's a new year, and it will be a busy one here in Iowa when it comes to evolutionary biology. I want to highlight two upcoming events: Iowa City's first annual Darwin Day celebration featuring a lecture by Massimo Pigliucci, and an upcoming symposium on evolution and intelligent design, featuring John Haught and Wesley Elsberry. These events will be held in February and March, respectively; more information on both of them after the jump.
Event Number One: Iowa City's First Annual Darwin Day Celebration
About: A celebration of science in general and biology specifically, with events…
tsmith | December 21, 2006Ho ho ho, and welcome to the early Christmas edition of Animalcules. Sit back, grab some hot cocoa, and click below to open your Christmas gift of some of the most interesting microbiology-themed blog posts over the past month.
To start us off with, in a new blog to me (the Cornell Mushroom blog), we learn how a fungus assists in the transmission of a nematode from the environment to the host--in this case, cattle. It's a fascinating example of commensalism.
From the same blog comes another post on Batrachochytrium dendrobatidis (or Bd), a fungus which is a cause of skin infections in…
tsmith | December 8, 2006As I've been busy this week, other Sciencebloggers (with Revere leading the fray and more posts here) have updated everyone on the newest developments in the case of the Tripoli Six (previous update here), the six medical workers on trial for their lives in Libya, accused of spreading HIV to more than 400 children in a hospital there. Nature's Declan Bulter broke news on a new Nature paper showing, using molecular phylogenetics, that the strains of HIV which infected the children were already circulating in the hospital prior to the medics' arrival--again, showing that these workers are…
tsmith | December 1, 2006 GOP wants law to define when fetuses feel pain
While they still can, House Republicans are looking at scheduling a vote next week on a fetal pain abortion bill in a parting shot at incoming majority Democrats and a last bid for loyalty from the GOP's base of social conservatives.
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The bill, by Rep. Chris Smith, R-New Jersey, defines a 20-week-old fetus as a "pain-capable unborn child" -- a highly controversial threshold among scientists. It also directs the Health and Human Services Department to develop a brochure stating "that there is substantial evidence that the process of being…
tsmith | October 24, 2006 Regular readers know an interest of mine are infections that cause more than just the typical acute spectrum of disease. For example, I've written on the role microbes might play in obesity, or the role of viruses in chronic disease such as cancer and, of course, AIDS. Still, typically, infections are thought of as acute and self-limited; that is, they infect the individual, cause illness, and are resolved in a matter of days or weeks, even though we know that this doesn't always happen. And increasingly, we're finding that infections are associated with all kinds of long-term diseases…
tsmith | October 23, 2006Apologies for the radio silence, so to speak. October has been a killer month for me and November won't be that much better, but I'll work on getting back to posting on a regular basis, including a new post for tomorrow. In the meantime, a few things to check out:
Mike on treating strep throat (which he's correct is near and dear to my heart--though not literally, thankfully, since they can cause heart disease!).
A belated Friday the 13th Tangled Bank
Last week's Grand Rounds.
tsmith | October 6, 2006I've mentioned frequently how my kids are fascinated with bugs and things creepy-crawly, whether it's spiders, giant moths, or butterflies. On that topic, via Bitch PhD comes this article from yesterday's New York Times on monarchs, their endangered habitat, and what just about anyone can do to help out.
(More after the jump...)
Pinching a bright orange butterfly in one hand and an adhesive tag the size of a baby's thumbnail in the other, the entomologist bent down so his audience could watch the big moment.
"You want to lay it right on this cell here, the one shaped like a mitten," the…
tsmith | October 2, 2006Ah, another day, another paper for the anti-HIV establishment to glom onto and misrepresent.
Last week's issue of the Journal of the American Medical Association published this paper examining the relationship between HIV load and CD4 T-cell decline:
Context Plasma human immunodeficiency virus (HIV) RNA level predicts HIV disease progression, but the extent to which it explains the variability in rate of CD4 cell depletion is poorly characterized.
Main Outcome Measures The extent to which presenting plasma HIV RNA level could explain the rate of model-derived yearly CD4 cell loss, as…
tsmith | September 21, 2006 That's certainly the claim in a new New York Times editorial (via The Frontal Cortex). The author, Nina Planck (author of Real Foods: What to Eat and Why), claims that it's as easy as just feeding cattle grass, and poof!--E. coli O157 will vanish.
More on this and why organic farming won't necessarily stop such outbreaks after the jump.
Planck writes:
Where does this particularly virulent strain come from? It's not found in the intestinal tracts of cattle raised on their natural diet of grass, hay and other fibrous forage. No, O157 thrives in a new -- that is, recent in the history of…
tsmith | September 20, 2006 The seventh chapter of Wells' book could be summed up in a single sentence: "biology doesn't need no steeekin' evolution!" Wells argues that, because medicine and agriculture were already doing just fine prior to Darwin's publication of Origin, clearly then, these fields (and others) haven't benefited from an application of evolutionary principles in the time from 1859 to present day, and that Dobzhansky's "nothing in biology makes sense except in the light of evolution" is one big joke.
Wells focuses on medicine and agriculture because these are two fields that we all benefit from, and…
tsmith | September 18, 2006And who said spinach was boring?
If the ongoing E. coli outbreak due to spinach has done one thing, it's highlight the mystery that revolves around Salinas, California:
The sunny Salinas Valley holds a dark mystery: Why, in the past decade, have nine Escherichia coli outbreaks been linked to produce grown here?
It's still unknown why this fertile land has been hit by what an FDA official calls "significant" crop contamination.
Throughout the picturesque terrain here, questions swirl.
Has cattle waste contaminated irrigation water? Does contaminated soil blow in the wind? Do birds feeding on…
tsmith | September 18, 2006It seems like every other story that comes out about H5N1 contradicts the previous one. I've blogged previously about some reasons to think that the diagnosed cases of H5N1 are only the tip of the iceberg (see here, here, and here, for instance). Though there I present some evidence to suggest that we may be missing asymptomatic or mild influenza cases, other stories have come to the opposite conclusion. For example, a recent news story from Cambodia reports that no mild or asymptomatic cases of H5N1 infection were found:
Researchers who tested 351 Cambodian villagers after they had…