Tag Archives: DNA

How Safe Is Traditional Chinese Medicine?

13 Apr

The following is written by Kai Kupferschmidt of sciencemag.org:

Dangers of Chinese Medicine Brought to Light by DNA Studies

Traditional Chinese medicine (TCM) is enjoying increasing popularity all over the world. But two molecular genetics studies published this week show that the trendy treatments can be harmful, as well. The papers focus attention on the fact that not all of their ingredients are listed, or even legal, and that some can cause cancer.

“These two studies show very clearly how dangerous the products of TCM can be,” says Fritz Sörgel, the head of the Institute for Biomedical and Pharmaceutical Research in Nuremberg, Germany, who was not involved in the work. “The public needs to be better informed about these dangers.”

Hundreds of millions of dollars are spent on TCM products each year—a growing portion of it on the Internet—and some scientists are looking at these preparations hoping to discover new pharmacological substances. Many would like to emulate the success of Tu Youyou, the Chinese scientist who isolated artemisinin, now the world’s most important malaria drug, from an ancient Chinese medicine. Tu won a Lasker award last year and is rumored to be a Nobel candidate.

But critics have long warned that some mixtures can also contain naturally occurring toxins, contaminants like heavy metals, added substances such as steroids that make them appear more effective, and traces of animals that are endangered and trade-restricted.

Now, researchers at Murdoch University in Australia have investigated the problem using modern sequencing technology. The team, based at the university’s Australian Wildlife Forensic Services and Ancient DNA Laboratory in Perth, analyzed 15 samples of traditional Chinese medicine seized by Australian border officials.

“We took these traditional preparations, smashed them to pieces, and extracted the DNA from the powder,” explains molecular geneticist Michael Bunce. The scientists then fished out copies of two specific genes, trnL, a chloroplast gene common to all plants, and 16srRNA, conserved among plants and animals, and multiplied and sequenced them. By comparing the sequences to those in genetic databases, they could pinpoint the animals and plants used to make the medicine. “Sometimes we really struggled to assign a particular DNA to a particular species,” Bunce says. But as genetic databases expand, this should become easier.

Some products contained material from animals classified as vulnerable or critically endangered, such as the Asiatic black bear and the Saiga antelope—just as the producers claimed. But often, the medicine also harbored ingredients not mentioned on the packaging, the team reports online today in PLoS Genetics. “For example, a product labeled 100 percent Saiga antelope contained considerable quantities of goat and sheep DNA,” Bunce writes.

“Using DNA to identify the animal species and thus prove illegal trading is very elegant,” says Dietmar Lieckfeldt, who works in molecular forensics at the Leibniz Institute for Zoo and Wildlife Research in Berlin, Germany. Identifying animals by their DNA has been possible for a while, he says, but the next-generation sequencing technology makes it possible to nail different species in a mixture very quickly.

In the herbal preparations, Bunce and his colleagues found members of 68 different plant families, among them plants of the genera Ephedra and Asarum. Both can contain toxic chemicals such as aristolochic acid, a compound banned in many countries because it causes kidney disease and cancer of the upper urinary tract (UUC). While detecting DNA from a certain species does not mean that a toxin produced by that plant is present, chemical analysis of one of the four samples containing Asarum DNA did turn up aristolochic acid.

The threat posed by aristolochic acid is also highlighted in a paper published in the Proceedings of the National Academy of Sciences on Monday. The researchers, led by pharmacologist Arthur Grollman of Stony Brook University, focused on Taiwan, the country with the highest rate of UUC in the world. A previous analysis had shown that roughly one-third of the Taiwanese population consumed herbs likely to contain aristolochic acid.

The scientists sequenced the tumors of 151 patients with UUC. Among patients with characteristic mutations in the important tumor-suppressor gene TP53—which make people more vulnerable to cancer—84% also showed a known molecular signature of exposure to aristolochic acid, they found. The study provides compelling evidence that aristolochic acid is a primary cause of UUC in Taiwan, the authors argue.

Bunce and his colleagues also found DNA from plant families known to contain medicinally important species that could pose risks when used in combination with other drugs, as well as DNA from soybean and plants of the cashew family, which can contain allergens. “This just shows that the ingredients in these preparations aren’t accurately declared,” Bunce argues. Indeed, says Sörgel, the studies show that partaking in traditional Chinese herbal medicine is a gamble: “We just don’t know enough about it.”

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Ph.Diddy

10 Apr


Turn it up, dance, and giggle.
Via D&A Lab, a totally awesome blog that every science nerd should check out.

Etsy Find: NBDesigns

26 Mar

I love finging science-themed artists on Etsy! NBDesigns features designs that perfectly balance talent, adorableness, and delight.
Their products include:
Bacterium earrings, complete with adorable monotrichous flagella and organelles.

Bacteriophage earrings

DNA Electrophoresis Ladder earrings

Erlenmeyer Flask of Love, complete with a itty bitty heart.

Petri Dish earrings


A microbiology charm necklace, featuring a bacterium, a heart flask, and a petri dish.

A necklace of a macrophage eating an itty bitty heart

And, because I am a complete coffee addict, I have to include these awesome golden coffee bean earrings.
 If I brewed them, would they taste like art?

Molecular Machines

11 Mar

I love this video, for so many reasons.
I love how he makes a point to talk about the importance of art in scientific research and education. Because of their tiny size, accurate artistic representation is the best tool science currently has to convey how molecule interact and behave.
I love how it gives one of the best scale perspectives of DNA and chromosomes that I’ve ever seen. Simply breathtaking.
And I love how he focuses on the specific fibers and signaling proteins, demonstrating how amazing our adorable little molecular machines are.
It’s a nine minute video, and worth every second of your time.
Enjoy!

New Type of Extra Chromosomal DNA Discovered

9 Mar

A team of scientists from the University of Virginia and University of North Carolina in the US have discovered a previously unidentified type of small circular DNA molecule occurring outside the chromosomes in mouse and human cells. The circular DNA is 200-400 base pairs in length and consists of non-repeating sequences. The new type of extra-chromosomal circular DNA (eccDNA) has been dubbed microDNA. Unlike other forms of eccDNA, in microDNA the sequences of base pairs are non-repetitive and are usually found associated with particular genes. This suggests they may be produced by micro-deletions of small sections of the chromosomal DNA.
(via PhysOrg)

Genetic Coffee

7 Mar

I love it when science validates my coffee addiction ^_^

Exercise and Caffeine Change Your DNA in the Same Way, Study Suggests

via Science Daily, March 6th, 2012

You might think that the DNA you inherited is one thing that you absolutely can’t do anything about, but in one sense you’d be wrong. Researchers reporting in the March issue of Cell Metabolism, a Cell Press publication, have found that when healthy but inactive men and women exercise for a matter of minutes, it produces a rather immediate change to their DNA. Perhaps even more tantalizing, the study suggests that the caffeine in your morning coffee might also influence muscle in essentially the same way.

The underlying genetic code in human muscle isn’t changed with exercise, but the DNA molecules within those muscles are chemically and structurally altered in very important ways. Those modifications to the DNA at precise locations appear to be early events in the genetic reprogramming of muscle for strength and, ultimately, in the structural and metabolic benefits of exercise.

“Our muscles are really plastic,” says Juleen Zierath of Karolinska Institutet in Sweden. “We often say “You are what you eat.” Well, muscle adapts to what you do. If you don’t use it, you lose it, and this is one of the mechanisms that allows that to happen.”

The DNA changes in question are known as epigenetic modifications and involve the gain or loss of chemical marks on DNA over and above the familiar sequence of As, Gs, Ts, and Cs. The new study shows that the DNA within skeletal muscle taken from people after a burst of exercise bears fewer chemical marks (specifically methyl groups) than it did before exercise. Those changes take place in stretches of DNA that are involved in turning “on” genes important for muscles’ adaptation to exercise.

When the researchers made muscles contract in lab dishes, they saw a similar loss of DNA methyl groups. Exposure of isolated muscle to caffeine had the same effect.

Zierath explained that caffeine does mimic the muscle contraction that comes with exercise in other ways, too. She doesn’t necessarily recommend anyone drink a cup of joe in place of exercise. It’s nevertheless tempting to think that athletes who enjoy a coffee with their workout might just be on to something.

Broadly speaking, the findings offer more evidence that our genomes are much more dynamic than they are often given credit for. Epigenetic modifications that turn genes on and back off again can be incredibly flexible events. They allow the DNA in our cells to adjust as the environment shifts.

“Exercise is medicine,” Zierath says, and it seems the means to alter our genomes for better health may be only a jog away. And for those who can’t exercise, the new findings might point the way to medicines (caffeinated ones, perhaps?) with similar benefits.

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Further evidence on why coffee is amazing. Exercise is ok too. Just not as awesome as coffee. A related article can be found at Nature, which is also pretty awesome ^_^

Itty Bitty DNA Sequencer

2 Mar

A tiny DNA sequencer the size of a flash drive? For only $900? Yes please.

 

 The MiniON has been used successfully to read the genome of the lambda bacteriophage, which is about 48500 base pairs in length. Pretty impressive, little guy. I love the thought of having lab equipment I can carry around in my purse at all times. You never know when a science moment will occur, and you want to be ready! Like some super awesome superhero of science!