General biology
tsmith | May 31, 2017A claim that scientists need to quit making:
I've written about these types of claims before. The first one--a claim that antimicrobial peptides were essentially "resistance proof," was proven to be embarrassingly wrong in a laboratory test. Resistance not only evolved, but it evolved independently in almost every instance they tested (using E. coli and Pseudomonas species), taking only 600-700 generations--a relative blip in microbial time. Oops.
A very similar claim made the rounds in 2014, and the newest one is out today--a report of a "super vancomycin" that, as noted above, could be…
tsmith | August 18, 2014
I'm happy to welcome Dr. Heather Lander to the blogosphere and Twitterverse. She's a virologist who has done work with some of the world's deadliest pathogens in a high-security biosafety level 4 laboratory. This is the type of lab where one must wear "space suits" to work with organisms. You've probably seen in dramatized in various movies and TV shows (such as The Walking Dead). Heather describes what it's really like to work in one--even while pregnant.
Dr. Lander, 9 months pregnant in a BSL4 lab
TS: Can you tell readers a bit about your background and research? How did you get…
tsmith | July 24, 2014Eleven years ago, two scientists made a bet. One scientist wagered that a new type of antimicrobial agent, called antimicrobial peptides, would not elicit resistance from bacterial populations which were treated with the drugs. Antimicrobial peptides are short proteins (typically 15-50 amino acids in length) that are often positively charged. They are also a part of our body's own innate immune system, and present in other species from bacteria to plants. It is thought that these peptides work primarily by disrupting the integrity of the bacterial cell, often by poking holes in them.…
tsmith | January 1, 2014Guest post by Tim Fothergill, Ph.D.
In January of this year the British Chief Medical Officer urged her government to add threat posed by superbugs to the official list of "Apocalypses to Worry About" along with catastrophic terrorist attacks and massive flooding. With typical British understatement, its actual name is the National Risk Register of Civil Emergencies but a very stark picture was painted of a post-antibiotic world in which routine operations, such as hip replacements, could prove fatal. In September, The Centers for Disease Control in the US issued a similar statement which…
tsmith | June 21, 2013Student guest post by Sean McCaul
Image Source: http://www.cejournal.net/?p=1934
The next time somebody in your office or household has the flu, you might want to consider keeping your distance. A new study published this month in Nature Communications suggests that about half of the transmission of influenza A results from inhalation of microscopic infectious droplets created by the coughing and sneezing of people infected with the flu. The flu virus hitches a ride in these droplets, and may infect nearby susceptible people who breathe them in.1
The influenza A virus generally causes…
tsmith | October 17, 2012Guest post by Hillary Craddock
Last week a new study regarding Eastern Equine Encephalitis (EEE) was published online (Bingham et.al.). EEE is a mosquito-borne virus that can cause serious, and sometimes deadly, disease in humans and equines. In warmer parts of North America, the virus is spread year-round, but in areas where mosquitoes get killed off in the winter it has been something of a mystery as to how the virus makes it from year to year. Humans and equines are both dead-end hosts, which means that a mosquito can not be infected from biting an infected person or horse. Researchers in…
tsmith | July 6, 2011While "flesh-eating infections" caused by the group A streptococcus (Streptococcus pyogenes) may grab more headlines today, one hundred and fifty years ago, the best known and most dreaded form of streptococcal infection was scarlet fever. Simply hearing the name of this disease, and knowing that it was present in the community, was enough to strike fear into the hearts of those living in Victorian-era United States and Europe. This disease, even when not deadly, caused large amounts of suffering to those infected. In the worst cases, all of a family's children were killed in a matter of a…
tsmith | June 23, 2011As I've laid out this week (part 1, part 2, part 3), the realization that a fairly simple, toxin-carrying bacterium could cause a "complex" and mysterious disease like hemolytic uremic syndrome came only with 30 years' of scientific investigation and many false starts and misleading results. Like many of these investigations, the true cause was found due to a combination of hard work, novel ways of thinking, and simple serendipity--being able to connect the dots in a framework where the dots didn't necessarily line up as expected, and removing extraneous dots as necessary. It's not an easy…
tsmith | June 3, 2011...when it contains a weird gene conferring methicillin resistance that many tests miss.
Methicillin-resistant Staphylococcus aureus (MRSA) has become a big issue in the past 15 years or so, as it turned up outside of its old haunts (typically hospitals and other medical facilities) and started causing infections--sometimes very serious--in people who haven't been in a hospital before. Typically MRSA is diagnosed using basic old-school microbiology techniques: growing the bacteria on an agar plate, and then testing to see what antibiotics it's resistant to. This can be done in a number of…
tsmith | May 18, 2011Ebola has long been associated with wildlife. From the early days, bats were viewed as a potential reservoir (though it wasn't confirmed that they actually harbored the virus until 2005). Contact with wild animals--particularly primates which were butchered for food--was also long thought to be a risk factor, and now we know that primates can become ill with Ebola and pass the virus to humans.
What hadn't been examined until 2008 were pigs. I mean, it's not exactly the animal you associate with central Africa, where many of the Ebola cases have been concentrated. However, pigs are much more…
tsmith | April 11, 2011We all know of once-respected scientists who ended up going off the deep end, adhering to an unproven idea despite massive evidence to the contrary. Linus Pauling and his advocacy of megadoses of Vitamin C, or Peter Duesberg's descent into HIV denial. It's all the more disappointing when the one taking a dive is a woman, since there are, compared to men, relatively fewer female "big names" in the sciences. So when one goes from views that were, perhaps, outside of the mainstream (but later proven largely correct) to complete science denialism, it makes it all the more depressing. Even worse,…
tsmith | October 4, 2010This is great. The College of Physicians of Philadelphia has launched a site on The History of Vaccines. I've been poking around, and there's an incredible amount of stuff to check out. They have a nice FAQ, Top 20 questions about vaccination, as well as some great activities (herd immunity! learn about Koch's postulates! understand the relative risk of vaccination versus other events!) and a metric fuckton of articles and images. Looks to be a fantastic resource for students, and for anyone interested in understanding vaccination.
tsmith | April 27, 2010Student guest post by Shylo Wardyn
"Of all the parasites I've had over the years, these worms are among the... hell, they are the best".
Was Fry from the animated show 'Futurama' right in his assessment of worms being good for him? Did he know something about parasitic worm infections that I was unaware of? Well, in the show, his parasites were doing remarkable things for his body, but does this translate to real life at all? Some people think so. Altman reviews the idea that over evolutionary time, our ancestors were infected with all sorts of parasites and this led to an interaction…
tsmith | April 27, 2010Student guest post by Desiré Christensen
Colorectal cancer (aka colon cancer) includes cancers of the colon, rectum, and appendix. Colorectal cancer is more common in developed countries (e.g. United States and Japan) compared to developing countries in Africa and Asia. Each year in the United States, there are around 150,000 cases of colorectal cancer diagnosed and about 50,000 people die from this cancer. Risk factors for colorectal cancer include lifestyle factors (e.g. habitual alcohol use; high-fat, low-fiber diet; obesity; sedentary lifestyle; smoking), family history of intestinal…
tsmith | April 26, 2010Student guest post by Andrew Behan
Malignant Mesothelioma (MM) is a rare type of cancer which manifests itself in the thin cells lining the human body's internal organs. There are three types of MM; pleural mesothelioma, peritoneal mesothelioma, and pericardial mesothelioma, affecting the lining of the lungs, abdominal cavity, and lining of the heart, respectively (1). Pleural mesothelioma is most common, consisting of about 70% of all MM cases and has a poor prognosis; patients live a median time of 18 months after diagnosis. (Note: for the purposes of this article, MM will be used to…
tsmith | April 26, 2010Student guest post by Jay Watson
Tired again? Perhaps it's the crappy weather, because you're sure that you've been getting enough sleep. After all, you can't remember the last time you spent less than ten hours in bed per night. Hopefully it's not mono; one of your friends had it a few months ago and it's all but knocked her out. However, you soon realize that you've only talked to her on the phone since she got engaged, so there's no way that's it. It's strange, even everyday activities like running errands has turned into something utterly exhausting. As you consider the reasons as…
tsmith | April 22, 2010Student guest post by Ron Bedford
The NYT (Kolata, 2010) recently published a story we'd all like to believe in. After their "lab's usual end-of-the-week beer hour," two Harvard neurology researchers noticed similarities between not only genes associated with both the innate immune system and Alzheimer's disease (AD), but structures, characteristics, and actions of selected proteins as well. Dr. Rudolph E. Tanzi, Dr. Robert D. Moir, and their team found "striking similarities" between the well-known innate immune system protein, LL-37, and amyloid β-protein (Aβ), long considered a waste…
tsmith | April 22, 2010Student guest post by Liz Stepniak
In the field of chronic disease, genetics has long been determined as a component of disease susceptibility. Infectious disease was believed to be caused by an agent of infection, such as a virus or bacteria which comprises a large environmental factor. In the past decade or so, this view has been expanded to include an important genetic factor as well.
There has been scientific evidence supporting the controversial idea that one error in a single gene can significantly alter the individual's risk of obtaining a bacterial infection. Can infectious…
tsmith | April 20, 2010Student guest post by D.F. Johnston
As the year marches forward, ever closer to that summer sun we missed so much during dreary winter days, we also get closer to the traditional summer picnics and barbecues. Sometimes, in our hurry to enjoy quality time with friends and family, we get distracted from our usual practices for proper food handling. We might try to get little Billy his hamburger before he has time for a full-fledged temper tantrum, so we hurry it along, figuring a tiny bit of pink in the middle won't be the end of the world. Or we might realize that we're short a couple of…
tsmith | April 20, 2010Student guest post by Laura Vonnahme
As a part of traveling to a developing nation, we are often required to take medical precautions. This generally includes a line-up of shots for various diseases, a few other tests, and various regimens of prophylaxis for possible diseases. I have often left these doctors appointments with a line of band-aids on my arm, a handful of prescriptions and a little weakness in my knees. However, I will readily admit that my malaria prophylaxis is often pushed to the back burner; in fact the last time I went to a developing nation, I didn't even get the malaria…