Manuel A Palacios / Tufts University

E. coli engineered to glow certain colors when excited by the right light can convey a top-secret message.

Scientists are tweaking bacteria to send encrypted messages that can be shipped via snail mail on sheets of paper-like material called nitrocellulose.

The recipient grows the bacteria with a select cocktail of nutrients and other chemicals. Once grown, each microbe glows one of seven colors when exposed to the right kind of light. Different colored microbes are arranged to represent different letters and symbols. If you know the nutrient and chemical cocktail as well as the keys to the code, you can decipher the message.

For an added layer of security, many glowing microbes can be sent along, but only those that survive a dose of a particular antibiotic will reveal the intended message when exposed to the right light. 

"There are several layers of encoding in the message," Manuel Palacios, a chemist at Tufts University in Medford, Mass., and lead author of a paper on the technique, told me today.

To prove the point, the team created a message that when exposed to ampicillin read "this is a bioencoded message from the walt lab at tufts university 2011." The drug kanamycin gave different glowing bacteria that encoded the message: "you have used the wrong cipher and the message is gibberish."

Palacios and his colleagues named this biological messaging steganography by printed arrays of microbes, or SPAM. They describe it in this week's issue of the Proceedings of the National Academy of Sciences. 

The technology is rooted in funding from DARPA, the military's high-tech research agency, which suggests real-world spies could be communicating with messages encoded in arrays of glowing bugs. 

"I love that this triggers all this discussion about spies and stuff," Palacios noted, but said practical applications are more likely to be found in the biotech world.

For example, a biotech company that develops a high-yielding variety of genetically modified corn could use this technique to give the plant an easily-identifiable characteristic that thwarts attempts to steal it. 

Currently, biotech companies stamp the genetic code of their modified crops, but genetic sequencing in the lab is required to read the stamp.

"With this method, we are demonstrating that we can encode genetic information and we can decode it into something that just by looking at it you will be able to know what the message is," Palacios explained. 

In this case, the message isn't top secret. Rather it is not obvious. So, for example, a corn stalk could be engineered to carry a biobarcode that can identify the plant as proprietary.

"That's where we might be seeing an application in the future," Palacios said.

More on secret messages:

• Strange twists in a DNA message
• Plants that glow on their own developed
• Researchers store data in DNA bacteria
• Spy trick hides message in plain sight

Caltech

Scientists have created an artifical neural network out of DNA, creating a circuit of interacting molecules.

Artificial intelligence is no longer the domain of clunky, mechanical robots and computers. It thrives inside a test tube, where scientists have created an artificial neural network made out of DNA — essentially the beginnings of a brain — that was able to ace "plop" quizzes.

The network is a circuit of interacting molecules that can recall memories based on incomplete patterns. It consists of four artificial neurons made from 112 distinct DNA strands and plays a mind-reading game in which it tries to identify a mystery scientist.

The team, led by bioengineer Lulu Qian at the California Institute of Technology, chose to build its network out of DNA molecules because, before brains evolved, molecular interactions inside single-cell organisms showed limited forms of intelligence such as searching for food and avoiding toxins.

"Molecules can act as biochemical circuits that process information and perform computational tasks," Qian explains in a video describing her team's work, which was published in the July 21 issue of Nature.

Because scientists can synthesize DNA strands with whatever base sequence they want, the researchers were able to program the molecules to function like a simple model neuron that fires only when it passes a certain threshold. Linked together, they behave like a network of neurons.

To play the plop quiz game, the neural network was trained to "know" four scientists, whose identities are each represented by a specific, unique set of answers to four yes or no questions, such as whether the scientist was British.

After thinking of a scientist, a human player provides an incomplete subset of answers that partially identifies the scientist. The player then conveys those clues to the network by plopping DNA strands that correspond to those answers into the test tube.

These plopped-in strands interact with the neural network, which fires or not depending on its answer. To see the neurons firing, a fluorescent molecular marker lit up when activated.

In this way, the network communicates via fluorescent signals to identify which scientist the player has in mind or that it has insufficient or contradictory information. The researchers played the game with the network using 27 different ways of answering the questions. It responded correctly each time.

Beyond playing lab games, the technology has applications for the design of new drugs as well as performing chemical and biological research, the scientists say. For example, biochemical networks designed to go inside a body could help identify a disease and deliver targeted drugs.

But that future is distant, Qian says. For one, finding a way to get the network to function inside a living organism presents a whole new set of challenges than operating inside the test tube.

As for creating an artificial human brain with lab-made DNA ... don't worry just yet. The four neuron network took eight hours to identify each mystery scientist. The human brain consists of 100 billion neurons and can make decisions in a split second.

(Via Discovery News)

More on artificial intelligence:

• Beyond 'Jeopardy': Watson wins
• What will happen when machines outthink us?
• Scientists work on artificial cat brain
• Neuron-like computer hardware finally gets software

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

Courtesy of William Holland

Marvin and William Holland, from left, sit beside Ntomnifor Richard Fru during an African-American reunion in June. Genetic analysis suggests that the Holland brothers are distantly related to Fru's Cameroonian family.

Thanks to 21st-century genetic testing, William Holland is finally able to show some of his African cousins what happened to his slave ancestors back in the 18th century. The climax of Holland's quest came last weekend, when about 60 African-Americans and Africans gathered at Franklin County Recreational Park in Virginia for a teach-in about his family's ocean-spanning, three-century saga.

The 42-year-old Holland, who lives in Atlanta, left his job at Coca-Cola and turned his focus to the family quest nine years ago. The quest is particularly difficult for African-Americans like Holland because their ancestors came over in chains with their African identity erased. Holland eventually figured out that his great-great-great-great-grandfather was brought over from Africa around 1772 and sold to a Virginia plantation owner. He even discovered that his great-grandfather, Creed Holland, was forced to serve in the Confederate Army during the Civil War.

But traditional genealogical research couldn't give Holland any further clues as to his African origins. Exactly where did his ancestors come from? Did he have any present-day cousins back in the old country? That's where genetic tests could point the way.

Holland had his DNA analyzed for markers that just might match up with African kin who had taken similar tests. Records held by the Sorenson Molecular Genealogy Foundation suggested that he might be related to the king of a region in Cameroon's Northwest Province, named Fon Angwafo III. When Holland visited Cameroon and laid out his records for the king and his counselors to inspect, he was welcomed as a long-lost relative. In fact, during a follow-up visit with other family members, Holland was ceremonially named Ndefru, after Fon Angwafo's father.

The Africans told how they lost their kin during the days of the slave trade — but when the African-Americans told how their ancestors lost their identity through slavery, Holland's Cameroonian cousins just couldn't believe it. So Holland invited "the Fon" and his family to come over to America and learn more about the other side of the slavery story.

It took months to make all the arrangements, and Fon Angwafo III himself couldn't make the trip because of political obligations at home — but late last month, the Fon's wife, Queen Kiko Anna Angwafo, finally arrived in America along with the king's son and nephew to see the region in Virginia where Holland's ancestor ended up. Holland and his family were the Africans' hosts for a family reunion on June 25. Cameroonians from the Mankon region ruled by the Fon and from the nation's West Region attended the event as well.

Courtesy of William Holland

African-Americans and African visitors wear traditional garb at the Frontier Culture Museum's West Africa farm exhibit near Staunton, Va. From left are William (Ndefru) Holland, Regina and Kamari Holland, Marvin (Tsi) Holland, Prince Peter Tseghama Angwafo, Willie Mae (Mankah) Holland, Queen Kiko Anna Angwafo, Ntomnifor Richard Fru and Eric Bryan, the museum's deputy director.

Courtesy of William Holland

Queen Kiko Anna Angwafo picks up a pestle at the Frontier Culture Museum's West Africa village exhibit.

One of the highlights was a visit to the Frontier Culture Museum in Staunton, Va., where a replica West African village has been built to give visitors a taste of life before slavery.

But the climax came when the Africans were taken to the old Holland plantation, where William Holland's ancestors lived as slaves (and took on the last name of their owners).

"The whole purpose was to tie in the missing links," Holland told me. And by that measure, he judged the reunion to be a great success. The Cameroonians saw a blacksmith shop from the Civil War era. They soaked in the history as they toured the plantation's old chicken house and slave kitchen. They walked around the graves where slaves and their owners were buried.

"They totally understood," Holland said. He quoted them as saying, "Now we know you weren't joking around when you told us about this. ... It's very clear now, the pain and suffering you went through when you came to America."

And there was a bonus: A descendant of the slave owners, John Sherrard Holland, served as the Africans' tour guide.

Courtesy of William Holland

William Holland's family and his African visitors meet with John Sherrard Holland, a descendant of the plantation owners who held William Holland's ancestors in slavery.

"It was a great honor and a pleasure to do that," the 55-year-old operator of a hunting preserve told me later. He went to school with members of William's family, and "we've always had the best of relationships," he said.

As for the dark past of slavery, John Sherrard Holland said that has been left far behind. "It's history," he said.

But William Holland said that history is worth reflecting upon once more, particularly at a time when America is celebrating Independence Day. He noted that when Americans heralded their freedom in 1776, his African ancestor had been unfree for four years. "Just imagine what he was thinking," Holland said.

"Is it time for celebration?" he asked. "I don't know. But now we're trying to do justice to that heritage — and that's something to celebrate."

Previous chapters in the tale of William Holland's roots:

• Sept. 8, 2010: DNA points to royal roots in Africa
• Feb. 1, 2011: Family roots get tangled up in Africa
• Feb. 28, 2011: Black history saga comes full circle 
• African American news from theGrio

 For further information about genetic testing for genealogical purposes, check out this guide on Cyndi's List, or this entry on Wikipedia. If you happen to be a Boyle looking for genealogical information, take a look at my Boyle family website. You can also connect with me via Facebook or Twitter. And if you really want to be friendly, ask me about "The Case for Pluto."

The Biodesign Institute Arizona State University

Figure 1 a and b display schematics for 2-D nanoforms with accompanying AFM images of the resulting structures. 1 c-e represent 3D structures of hemisphere, sphere and ellipsoid, respectively, while figure 1f shows a nanoflask, (each of the structures visualized with TEM imaging).

Earlier this week, we learned about wedding rings made out of DNA. Now, the ability to fold stringy bits of DNA into patterns and shapes has gone 3-D thanks to a new technique pioneered at Arizona State University's Biodesign Institute.

The breakthrough, reported in the April 15 issue of Science, is a step on the road to eventually using the procedure to create diminutive drug delivery devices, nano-computers, and chemical factories.

So-called DNA origami was introduced in 2006 by Paul Rothemund of the California Institute of Technology. It hinges on the self-assembling properties of DNA's four complimentary base pairs, which form the famous double helix.

These nucleotides, labeled A, T, C and G, follow a formula of how they interact. A always pairs with T and C with G. DNA origami practitioners exploit this base pairing to create complex shapes, but until now most shapes were two dimensional.

To do this, they frame the desired shape with a length of single-stranded DNA and then use DNA "staple strands" to cross over and integrate the structure and hold the desired shape.

"Our goal is to develop design principles that will allow researchers to model arbitrary 3-D shapes with control over the degree of surface curvature," Yan Liu of the Biodesign Institute, said in a news release explaining the research.

"In an escape from a rigid lattice model, our versatile strategy begins by defining the desired surface features of a target object with the scaffold, followed by manipulation of DNA conformation and shaping of crossover networks to achieve the design."

To achieve this, the team starts with simple, 2-D concentric ring structures formed from a DNA double helix and bound together at strategically placed crossover points. Varying the number of nucleotides between crossover points allows the designer to combine sharp and rounded elements into 2-D and 3-D forms.

More on tricks with DNA:

• 'Wedding Rings' made out of DNA
• Slideshow: Making smiley faces from DNA
• DNA robots pave way for microscopic factories 
• DNA twisted into pretzels
• Play a game and engineer real RNA 

Alexander Heckel

The world's smallest wedding rings are built up from two interlocked strands of DNA.

Thorsten Schmidt can now say he had a hand in creating the world's smallest wedding rings, measuring less than a thousandth of the width of a human hair.

The interlocked rings, known as catenans (after the Latin word for "chain"), were made from looped strands of DNA and measure just 18 nanometers wide. The wedding angle comes about not only because of the rings' perfectly circular shape, but also because Schmidt got married while he was working on the experiment.

These rings aren't just a romantic gesture: Because they're freely pivotable, they could be useful components in nano-machines or molecular motors.

"We still have a long way to go before DNA structures such as the catenan can be used in everyday items," Professor Alexander Heckel, Schmidt's co-author and adviser at Germany's Goethe University Frankfurt, said in a news release, "but structures of DNA can, in the near future, be used to arranage and study proteins or other molecules that are too small for a direct manipulation, by means of auto-organization."

Heckel and Schmidt / ACS Nano Letters

An atomic force miroscope image shows the interlocked DNA rings, along with an illustration showing how they're chained together.

The experiment, reported in the journal Nano Letters, involved creating two C-shaped DNA fragments that were positioned with their open ends pointing away from each other. Polyamide bonds were attached to the DNA to anchor the fragments to each other, and then the researchers added an oligonucleotide to close each of the C-sections and form the rings. The operation was done with mere chemistry. No nanometer-sized tweezers were required.

The paper notes that the assemblages resemble "stylized wedding rings," and here's the icing on the cake: Schmidt, who is now at Harvard's Wyss Institute for Biologically Inspired Engineering, dedicated the paper "to his wife and colleague Dr. Diana P. Goncalves Schmidt on the occasion of their wedding." Let's see Prince William top that one!

More tricks with twisty molecules:

• DNA folded into a world of patterns
• Slideshow: Making smiley faces from DNA
• DNA robots pave way for micro-factories
• The latest twist: Pretzels made of DNA
• Play a game and engineer real RNA

Join the Cosmic Log community by clicking the "like" button on our Facebook page or by following msnbc.com science editor Alan Boyle as b0yle on Twitter. To learn more about my book on Pluto and the search for planets, check out the website for "The Case for Pluto."  

Paula Bronstein / Getty Images file

A new test can determine a person's age to within nine years from a drop of blood.

Crime scene investigators with little more to go on than a drop of blood have a new test that can help them determine the age of the person who was bleeding, according to a study in today's issue of Current Biology.

The test will work even on dried bloodstains -– perhaps even those revealed by a heat-vision camera. This could help detectives reopen cases that went cold years ago. And it's only a matter of time before screenwriters start working the technology into the plotlines for "Law and Order" or "C.S.I."

The technique, developed by scientists at Erasmus MC University Medical Center Rotterdam in the Netherlands, is based on the fact that certain DNA molecules in some blood cells decrease with age, TG Daily reports:

"The molecules used are residues of the immune system known as sjTREC molecules. These special DNA molecules are released in blood cells as a result of the adaptations that have to be made by newly formed specific immune cells -- T cells -- to recognize bacteria, viruses, parasites or possibly cancer cells. Their number decreases with age."

The age test is accurate to within nine years. That should be sufficient to place unknown people –- criminals or missing persons, for example -– into generational categories spanning about 20 years.

Study co-author Manfred Kayser, a professor of forensic molecular biology, said in a news release that this is a harbinger for what's to come, as researchers uncover new methods designed to reconstruct the appearance of unknown persons from biological samples at crime scenes.

One test, for example, can determine eye color from DNA and has already been put to forensic use.

"Conventional DNA profiling applied in forensics can only identify persons already known to the investigating bodies, because the approach is completely comparative," he said. In cases where the DNA at the scene doesn't match any known suspect tested, "it is expected that appearance information estimated from evidence material will help in finding unknown persons."

More about the forensic frontier:

• New camera 'sees' invisible blood stains
• Cat fur puts criminals behind bars
• Crime labs cut to the bone
• Readers, pick your poison

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).