viruses
mikethemadbiologist | June 26, 2008In a Journal of Infectious Diseases commentary about this article, there's a fascinating discussion of the relationship between the HTLV-1 virus, which can cause T-cell leukemia in about one percent of those infected, and gastric cancer caused by the bacterium Helicobacter pylori. And it's not what you would expect.
Here's the summary (italics mine; references removed for clarity):
In this issue of the Journal, Matsumoto et al. asked whether human T lymphotropic virus type 1 (HTLV-1) antibody status is associated with the risk of developing gastric cancer. In a cohort of >5000 patients…
edyong | June 24, 2008In 1994, a third of the lions in the Serengeti were killed off by a massive epidemic of canine distemper virus (CDV), an often fatal infection that affects a wide range of carnivorous mammals. Seven years later, a similar epidemic slashed the lion population in the nearby Ngorongoro Crater. While CDV was undoubtedly involved, the scale of the deaths was unprecedented. What was it about the 1994 and 2001 epidemics that claimed so many lives?
Now, a team of scientific detectives led by Linda Munson from the University of California Davis, have solved the mystery. It turns out that the lions'…
sporte | June 4, 2008Have you ever wondered what kinds of viruses can be found in human waste?
Mya Breitbart and team have been sequencing nucleic acids from fecal samples in order to find out. You might expect that we'd find viruses that infect humans or viruses that infect the bacteria in our gut.
I wouldn't have expected to learn the result that they found.
A large number, 60% of the viral DNA sequences were from unknown viruses. That's not a surprise. The surprise came when they looked at the RNA viruses.
Instead, the viral sequences most often came from a plant pathogen called the pepper mild mottle…
mikethemadbiologist | May 13, 2008According to a recent Applied and Environmental Microbiology paper, influenza viruses are able to survive on banknotes. Lookie, bar graphs:
(from the paper) Duration of infectiousness according to the size of the initial inoculum and the presence or absence of mucus. Influenza A/Moscow/10/99 (H3N2) virus was deposited in triplicate on banknotes at the following concentrations, each in the presence (H3m) or absence (H3) of respiratory mucus: (A) 8.9 x 10e5 TCID50/ml; (B) 4.4 x 10e5 TCID50/ml; (C) 2.2 x 10e5 TCID50/ml; (D) 1.1 x 10e5 TCID50/ml. (E) Similarly, influenza B/Hong Kong/335/2001…
sporte | April 27, 2008A potential link between lung cancer and human papilloma virus may make parents even more glad about vaccinating their children with Gardasil®. Not only are the children protected against viruses that commonly cause cervical cancer, they may be protected against some forms of lung cancer as well.
The April 25th version of Nature News reports (1) that two viruses, HPV (Human papilloma virus) and measles virus, have been found in lung tumors.
From Nature News:
Samuel Ariad of the Soroka Medical Center in Beer Sheva, Israel, and his colleagues began by analyzing tumours taken from 65 lung…
edyong | April 25, 2008
If it looks like a dead cell and it feels like a dead cell, be careful - it could be a virus. Viruses are experts at infiltrating and exploiting cells but some are so big that they need to use special tricks. The Vaccinia virus is one of these. It belongs to the same family as the more infamous variola virus that causes smallpox. This group are among the largest of viruses, dwarfing many other types by a factor of ten. But despite its size, Vaccinia relies on stealth rather than brute force.
It's a mimic and it disguises itself as cellular flotsam. Vaccinia carries a molecular tag on its…
edyong | April 16, 2008
Of the different types of flu virus, influenza A poses the greatest threat to human health and at any point in time, about 5-15% of the world's entire population are infected with these strains. Together, they kill up to half a million people every year and the death toll rises sharply when pandemics sweep the globe.
Today, two papers published in Nature and Science shed new light on the origins of these epidemics. By prying into the private lives of flu viruses, the studies provide fresh clues about the birthplaces of new strains, their flight plans around the world and the locations…
mikethemadbiologist | April 10, 2008Several people have argued that if an influenza pandemic were to occur, it will rapidly evolve to become less virulent--that is less deadly. A recent paper explains why this might be wrong.
Basically, the flaw with the 'optimistic' argument is that it is assumes that the virus will be optimally fit given its environment (lots of fat, juicy hosts to kill). As it starts to kill off its hosts, its virulence (ability to make dead people or 'deadliness') and transmission rate (ability to infect new hosts) will decrease to another optimal point where the virus will be able to maximize its…
mikethemadbiologist | April 7, 2008A survey of Florida teens' sexual health knowledge yielded some very disturbing results:
A recent survey that found some Florida teens believe drinking a cap of bleach will prevent HIV and a shot of Mountain Dew will stop pregnancy has prompted lawmakers to push for an overhaul of sex education in the state.
There's been a lot said in favor of real sex ed and against abstinence-only 'education' (and rightly so), but, if the consequences of unwanted pregnancy and HIV weren't so serious, this other finding would be funny:
The survey showed that Florida teens also believe that smoking marijuana…
mikethemadbiologist | April 2, 2008When I started blogging, I never (EVAH!) thought I would describe the biology of E. coli with a Tolkein poem:
All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost.
From the ashes a fire shall be woken,
A light from the shadows shall spring;
Renewed shall be blade that was broken,
The crownless again shall be king.
I'm referring, of course, the spinach outbreak strain of E. coli O157:H7. You know, this one:
It turns out that this particular strain of E. coli O157:…
mikethemadbiologist | March 13, 2008No, that's accurate:
The first national study of four common sexually transmitted diseases among girls and young women has found that one in four are infected with at least one of the diseases, federal health officials reported Tuesday.
Nearly half the African-Americans in the study of teenagers ages 14 to 19 were infected with at least one of the diseases monitored in the study -- human papillomavirus (HPV), chlamydia, genital herpes and trichomoniasis, a common parasite.
The 50 percent figure compared with 20 percent of white teenagers, health officials and researchers said at a news…
edyong | February 27, 2008
Male insects have a tough time of it. Aside from the usual threats of predators, competitors and the odd hungry female, many are plagued by discriminatory parasites intent on killing them, while leaving their female peers unharmed. These "male-killers" are incredibly successful and infect a wide range of insects, who are themselves a very successful group. One of these killers, a bacteria known as Wolbachia, may well be the world's most successful parasite.
The male-killers are paragons of selfishness. Their success hinges on successfully infecting females, for whithin egg cells, they find…
mikethemadbiologist | January 23, 2008I'm posting about this because I want Orac's head to explode. Apparently, the first episode of the ABC legal drama, "Eli Stone", involves the protagonist taking up the mercury militia, anti-vax cause:
While police and legal dramas often use ripped-from-the-headlines topics as the basis of episodes, rarely do broadcast networks allow themselves to stray into the middle of heated debates that contain such emotional touchstones for large segments of their audience, if only because another big segment of a network's audience is likely to be on the other side of the debate.
With "Eli Stone,"…
mikethemadbiologist | January 22, 2008Olivia Judson describes what it would take to prevent almost all rabies deaths from Africa (rabies currently kills around 55,000 people annually):
To eliminate the disease from humans, therefore, it needs to be eliminated from dogs. And the way to do that is through dog vaccination. (At first, it may seem perverse to vaccinate dogs rather than humans, given that it's humans we want to protect. But because rabies is spread by dogs, not people, we can't break the chain of transmission unless we vaccinate the animals that spread it.)
The crucial factor in predicting the spread of an infectious…
mikethemadbiologist | December 19, 2007
...the Chikungunya virus might have something to say about that (if it could speak). From PLoS Pathogens:
Chikungunya virus (CHIKV) is an emerging arbovirus associated with several recent large-scale epidemics of arthritic disease, including one on Reunion island, where there were approximately 266,000 cases (34% of the total island population). CHIKV is transmitted by Aedes species mosquitoes, primarily Ae. aegypti. However, the 2005-2006 CHIKV epidemic on Reunion island was unusual because the vector responsible for transmission between humans was apparently the Asian tiger mosquito, Ae.…
mikethemadbiologist | December 12, 2007Earlier this week, I attended the International Human Microbiome Consortium Meeting (the human microbiome consists of the organisms that live on and in us). I'm not sure to make of the whole microbiome initiative, but one thing is clear to me: this is being driven by the wrong group of scientists.
Instead of being directed by biologists (medical primarily) who have devised a set of important questions, and want to use the power of high throughput genomics, including metagenomics which sequences of all the DNA in a specimen--bacteria, viruses, fungi, protozoa, and, yes, human (which raises…
mikethemadbiologist | November 30, 2007Or is it Lazarai? Either way, The New Yorker has an interesting article about recreating extinct viruses. To be precise, the article deals with recreating retroviruses.
Before you get all het up about the Evul Scientists creating a new AIDS or some hooey, most mammalian genomes (and other organisms) are chock full off degenerate--non-functional--retroviruses. Presumably they would up in these genomes by infecting the host, so figuring out what ancient viruses look like can help us figure out how today's viral threats work. While there's some hyperbole in the article, it's still a pretty…
sporte | October 25, 2007The next time you bite into a crisp juicy apple and the tart juices spill out around your tongue, remember the honeybee. Our fall harvest depends heavily on honeybees carrying pollen from plant to plant. Luscious fruits and vegetables wouldn't grace our table, were it not for the honeybees and other pollinators.
Lately though, the buzz about our furry little helpers hasn't been good. Honeybees have been dying, victims of a new disease called "colony collapse disorder," with the US, alone losing a large number of hives in recent years.
Why?
Researchers have speculated about everything…
sporte | September 26, 2007For the record: Chlamydia is NOT a virus.
I am bummed. I like the little MicrobeWorld radio broadcasts, and the video podcasts are even more fun.
But I was perusing the archives and I found this:
I could ignore this if it came from a different source, but MicrobeWorld is produced with funding from the American Society for Microbiology!
Microbiologists are supposed to know the difference between bacteria and viruses. It's part of our training and big part of what we do.
I know, as scientists we're always supposed to follow the mantra of "buyer beware" and "be skeptical of…
sporte | September 11, 2007Two protein structures from an avian influenza virus are shown below. One form of the protein makes influenza virus resistant to Oseltamivir (Tamiflu®)
Don't worry, these proteins aren't from H5N1, but they do come from a related influenza virus that also infects birds.
technorati tags: molecular models, protein structures, influenza, bioinformatics, Cn3D
One protein structure is from a strain that is sensitive to an anti-viral drug called "Tamiflu®". The other structure is from the same virus, except there's a slight difference. A single base change in the viral RNA changed the codon that…