Teflon for Teeth

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I may come to regret the title of this post given the chemophobia and fear surrounding fluoride and water fluoridation, but recent research suggests that fluoride may help prevent bacteria from causing cavities by creating a non-stick surface on teeth.

Read more at PLOS Blogs.

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The Story Behind a Potential Protein Treatment for Achondroplasia

Injecting sFGFR3 induces bone growth in wildtype mice (WT) and achondroplastic mice (Fgfr3ach/+). Adapted from Fig. 2 (1).
Injecting sFGFR3 induces bone growth in wildtype mice (WT) and achondroplastic mice (Fgfr3 ach/+). Adapted from Fig. 2 (1).

Earlier this week, several news outlets reported on a decoy protein as a potential treatment for achondroplasia or, more commonly, dwarfism, but made no mention of its origins.

From the New York Times:

Injections of a decoy protein can restore normal bone growth in mice with dwarfism characteristics, according to a new study, suggesting a possible treatment for humans with the condition.

People born with achondroplasia, the most common form of dwarfism, tend to be short in stature with short arms and legs and a relatively larger head, sometimes resulting in problems with the spine and with hearing and breathing. The condition is caused by a single mutation in the gene Fgfr3, which provides instructions for making a protein involved in the development of bone and brain tissue.

The Fgfr3 gene codes for fibroblast growth factor receptor 3 (FGFR3), a protein found on the surface of cells that in essence serves as an antenna that cells use to communicate with each other.  Continue reading

Dog-day Cicada

Found this little bugger on my tire this morning.

A post shared by AmasianV (@amasianv) on

This past spring, my girlfriend and I were in Virginia for a wedding when the 17-year Brood II cicadas were just starting to emerge. We were excited by the possibility of seeing some on our trip, but unfortunately, we didn’t spot any–I think we were too early?

Well, I can rest easy now after finding this lil’ bugger perched on the tire of my car yesterday morning. I believe this is a “dog-day” cicada, or annual cicada, which is different from the 13- and 17-year periodic cicadas that have been all up in the news. Dog-day cicadas typically have a 2-5 year life cycle and their broods are not synchronized. Overlapping broods ensure that dog-days cicadas appear every summer, usually in July and August, but it also means they don’t swarm like their periodic cousins.

Still pretty cool looking nonetheless.

Photo 51

Rosalind Franklin doodle

Today’s Google Doodle honors Rosalind Franklin, whose work on X-ray diffraction was instrumental in determining the double helix structure of DNA. In the Doodle she’s staring at an X-ray diffraction image, known as Photo 51, that got the ball rolling. If you’d like to learn more about how the structure of DNA was determined, Nova has a great interactive dissection of Photo 51 that helps unravel the double helix structure from what looks like just an “X.”

After her work on DNA, she “conducted pioneering work into the structure of viruses.” Sadly, she died due to complications of ovarian cancer in 1958–four years before the Nobel Prize was awarded to Watson and Crick for their research on nucleic acids, and at the time much of her contribution was overlooked.

I can’t help but wonder what else she would have accomplished had she not passed away.

Alien Faces or Larval Butts?

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Image credit: Chen Young

These might look like mugshots of unsavory patrons that frequent the Mos Eisley Cantina, but they’re actually the posterior ends of larvae from 6 different species of crane flies. The dark circles that resemble eyes are in fact breathing holes called spiracles. Instead of lungs, insects have a respiratory system made of a network of tubes and ducts, called trachea and tracheaoles, connected directly to the outside world by spiracles. These breathing holes are used by both the larva and adult forms of insects and can be found running along the length of the insect’s body.

Spiracles
Spiracles on the side of catepillar.

Just below the spiracles is the larva’s anus surrounded by anal pads, which give the “alien face” the appearance of a mouth or teeth (imagine having a set of nostrils right above your anus!).

Ponda Baba and Muftak meme

The larvae of many crane fly species are aquatic or are found in wet environments. Since crane fly larvae do the majority of their breathing through their posterior spiracles the odd, tentacle-like protrusions may be adaptations that  help them breathe. For instance,  the hairs and bristles covering the protrusions can trap air when the larvae are submerged in water.

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Posterior spiracles of a crane fly larva.

Adult crane flies are often confused for being male mosquitos or even mosquito hunters, despite the fact that they generally feed on nectar or in some cases nothing at all–the adult flies of some species exist only to mate. You’ve all probably seen crane flies before, wobbly flittering around looking like drunk daddy longlegs with wings.

Tipula paludosa
Adult Tipula paludosa crane fly
The Mos Eisley Cantina scene from Star Wars Episode IV – A New Hope:

Related Reading

Should I start patenting the cDNAs I’ve made in the lab?

In a unanimous decision today, the SCOTUS struck down patents for genes by ruling against Myriad Genetics in Association for Molecular Pathology vs. Myriad Genetics. The Court, however, did leave some wiggle room for companies to patent cDNAs, or complementary DNA.

“In Myriad, the high court held cDNA is patentable, because it involves actual work in the laboratory and inverts the normal process found in nature. The synthetic DNA is an edited version of a gene, stripped of non-coding regions that the court said makes it “not naturally occurring.”

Critics say even the edited sequences are directly analogous to naturally occurring DNA.”

In many labs, cDNAs are routinely made, manipulated, and used for research. cDNA is DNA that is engineered in reverse using messenger RNA (mRNA) as the template. As the above quote alludes, a cDNA is not a carbon copy of its corresponding gene. Interspersed along the length of a gene are regions of non-coding DNA sequence. These are segments of DNA that aren’t represented in the sequence of the encoded protein. When a gene is initially transcribed into mRNA some of these non-coding regions, called introns, are included. Introns, however, are ultimately removed by the cell before the mRNA is translated into protein. Since mRNA is used to make cDNA, the introns are excluded from the cDNA sequence.

gene expression
During gene expression, a gene is first transcribed into a primary RNA transcript, which includes non-coding introns (blue). Through a process called splicing the introns are removed from the transcript resulting in a mature mRNA molecule. The sequences found in mRNA are called exons (red and yellow). The mRNA is  then translated into protein. Since cDNA is made from mature mRNA, it will consist only of exon sequences.

Although gene and cDNA are different, they both carry essentially the same DNA sequence for a protein. (It should be noted, however, that many genes encode multiple forms of a protein, for which each form has its own corresponding cDNA.) So, I’m not sure why the “patentable” emphasis is on cDNAs as opposed to making mutations* to the underlying sequence that result in say, new or altered function of a protein. At least there I could see an inventive process happening–or am I missing something here?

*I’m talking about generating novel mutations. Of course, I’m not sure what should happen if said mutations are discovered to be “naturally occurring” after the fact.

Related Reading:

Patents on Nature

 

 

Crossposted at Scientopia

It’s An Evolutionary Trap!!!

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“A Cuban Tree Frog tries to eat a Christmas light. Photo by James Snyder. National Geographic My Shot”

You might be wondering why a frog would eat a Christmas light, but it may have simply confused the glowing bulb for a luminescent insect it normally feasts on. This is just one example of how even the mundane ways we’ve changed the environment can trip up other creatures–and sometimes with evolutionary consequences. As Carl Zimmer explains in a blog post over at The Loom,

We have altered the environment in a vast number of ways, both small and large. And when animals try to read the cues from our human environment, they can get tricked. They can end up doing something that kills them, loses them the opportunity to reproduce, or simply wastes their time. Scientists call these situations evolutionary traps.

Hydropsyche pellucidula
Caddisfly species Hydropsyche pellucidula
While the Cuban tree frog ultimately spit out its mistaken meal and survived its run-in with holiday lighting, other organisms are not as fortunate.

When caddis flies become adults and are ready to mate, they need to get to a body of water. Without Google Maps to help them, they do what their ancestors have done for countless generations: they take advantage of the fact that ponds and streams change the reflection of moonlight, altering its polarization. Unfortunately, large plate glass windows can polarize light in the same way, with the result that caddis flies will sometimes blanket the glass, mate, and lay their eggs there.

Carl Zimmer goes on to mention several other examples of evolutionary traps, like the Australian beetles that vigorously try to mate with empty beer bottles, and also discusses ways that we might disarm them. Head over there and have a read.

It's an evolutionary trap

I couldn’t resist.

 

Cultural Comic Books for Educating Asian Americans about Hepatitis B

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May is Asian-Pacific American Heritage Month and also Hepatitis Awareness Month. Coincidentally, Asian Americans are at great risk for hepatitis B, yet have the lowest rates of screening and vaccination. According to the CDC, of the estimated 1 million Americans with chronic hepatitis B about half are from the Asian/Pacific Islander (API) communities. For comparison, Asian Americans make up roughly 5% of the US population. Nearly 1 in 12 Asian Americans are chronically infected with hepatitis B, but many are unaware of their status.

How might we raise hepatitis B awareness for this cultural diverse group? Why, cultural comic books (sorta) of course!

There’s the story of a young Chinese American couple planning on getting married, but on the day of the proposal the bride-to-be confesses to her fiance that she has hepatitis B. Then there’s the one about a Korean immigrant family in which the father, who prefers traditional Asian medicine over Western medicine, discovers that his brother has liver cancer. Lastly, there’s the story of a Vietnamese American nail salon owner whose husband is diagnosed with hepatitis B, which was probably contracted by sharing razors with an infected roommate in college. No, these are are not vignettes from an Asian American film about coincidence. These are cautionary tales used in cultural, comic book-like photonovels that were developed to raise hepatitis B awareness among Asian Americans–the racial/ethnic group with the greatest risk of contracting hepatitis B.

You can read more of my post at PLOS Blogs

Blight-Resistant Potato: an “Acceptable” GMO?

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“Potato Blight Effects”

Last week, I wrote about a disease-causing nematode that infects the roots of soybean plants and  a mutation in one strain of soybeans that makes them resistant to these nematodes. In the post I mused,

what if an already existing gene variant with a desired trait from one organism is genetically engineered into another organism of the same species? Would this make GMOs a little bit more palatable to their detractors?

While intended to be more of a thought experiment, a commenter alerted me to a very similar scenario playing out in Ireland, where potato crops are still affected by blight–yes, as in the blight responsible for the Great Famine of the mid-1840s. Blight makes potatoes rot and is caused by infestation of a fungus-like organism (oomycetes) called Phytophthora infestans.

In recent years, scientists have developed blight-resistant GMO strains of potato plants by introducing a blight-resistance gene called RB into the potato’s genome. This gene was identified in Solanum bulbocastanum, a wild potato plant native to Mexico that is closely-related to potatoes. Resistance to blight most likely developed as a result of coevolving with P. infestans, which is considered to be native to Mexico as well.

The scenario facing GMO potatoes, however, is a little bit different from the question I posed earlier since the RB gene isn’t found in cultivated potato plants. Furthermore, traditional breeding methods have been unsuccessful in making hybrids between cultivated potatoes and S. bulbocastanum, therefore necessitating genetic engineering. There are, however, other blight-resistant wild Solanum plants, such as Solanum venturii, that can be hybridized with cultivated potatoes. But using the RB gene from S. bulbocastanum remains the most attractive option because S. bulbocastanum is resistant to the most number of blight-causing P. infestans strains

The response from one anti-GM campaigner to using genetic engineering in this case?

It is just there to make GM more palatable to the general public. The fact that it comes from a related plant doesn’t make it any different. The real danger is the process.

I guess that answers my question.

Immigration Reform: A Second Chance for Undocumented Immigrant Health?

When the Affordable Care Act was signed into law in March of 2010, many immigration advocates were disappointed that the bill left undocumented immigrants out in the cold. While the law kickstarts the process of bridging the gap for millions of uninsured Americans, specific language was written into the legislation to bar undocumented immigrants from being “eligible for public insurance or any type of private coverage obtained through exchanges.” At the time of the bill’s signing, approximately 7 million out of an estimated 11 million undocumented immigrants in the US were without insurance, and many of whom were living in poverty. These numbers are only expected to increase [1]. With immigration reform highly visible in Obama’s second term, immigration advocates are now viewing this as a second chance to address a growing public health concern.

Read more at PLOS Blogs…