Stories tagged Life Science

May
02
2013

Non-robotic jellyfish: Engineering researchers at Virginia Tech are building robots that mimic the efficient way jellyfish get around.
Non-robotic jellyfish: Engineering researchers at Virginia Tech are building robots that mimic the efficient way jellyfish get around.Courtesy Andy Field (Field Offie)
Researchers at Virginia Tech are working on several versions of robotic jellyfish that someday could be used by the military, or for mapping the ocean floor, or cleaning up oil spills.

Known affectionately as RoboJelly, the silicone blobs range from the size of a baseball to a giant five-foot floating monster. Each mimics the swimming technique used by jellyfish, those huffing and puffing water-bags that populate the world's oceans.

In nature, most jellyfish propel themselves by the seemingly simple expansion and contraction of their umbrella, using it to push water out like a rocket blast that propels it forward. But the fluid dynamics are a little more complicated than than just expelling out a big blast of water and moving the other way. It's more like when your cigar-smoking uncle would blow smoke rings into the air to impress you. Remember that? I do. These are called vortex rings, and it's the efficiency of the hydromedusean's self-created fluid flow that interest the VT researchers.

Students at VT's College of Engineering use thin layers of silicone - the same material used for swimming masks - to construct the robots. Electric batteries in watertight plexiglass boxes are used to power the mechanical blobs. The researchers are also looking into ways of extracting hydrogen from water to power them.

“Nature has done great job in designing propulsion systems but it is slow and tedious process," said Shashank Priya, associate professor at Virginia Tech, and the project's lead researcher. "On the other hand, current status of technology allows us to create high performance systems in a matter of few months.”

The on-going project involves a number of U.S. universities and industries, and will warrant several additional years of research before any prototypes are released for use. Besides possible military application, RoboJelly could be employed for such things as monitoring ocean currents and conditions, cleaning up oil spills, and studying sea-bottom flora and fauna.

SOURCES
Story at EarthSky.org
Virginia Tech website

Apr
29
2013

Coelacanth: model in the SMM paleo lab. Photo by Mark Ryan.
Coelacanth: model in the SMM paleo lab. Photo by Mark Ryan.Courtesy Fancy Horse (underwater background)
The genome of the coelacanth, the world's best known living fossil, has been sequenced by an international team of researchers and is revealing something scientists already suspected: that the primitive-looking fish has evolved more slowly than most other organisms. The coelacanth is related to the lungfish and several extinct Devonian fish species that are considered precursors to land dwelling tetrapods. Kerstin Lindblad-Toh is senior author of the study which appeared recently in the science journal Nature.

"We often talk about how species have changed over time, but there are still a few places on Earth where organisms don't have to change, and this is one of them," Lindblad-Toh said. "Coelacanths are likely very specialized to such a specific, non-changing, extreme environment -- it is ideally suited to the deep sea just the way it is."

Lindblad-Toh is scientific director of the Broad Institute's vertebrate genome biology group in Cambridge, Massachusetts, which did the genome research. The institute is linked to both MIT and Harvard.

The genetic map, which involved sequencing some 3 billion letters of DNA, also showed (via RNA content) that tetrapods - four-legged land dwelling animals - though related to both coelacanths and lungfish, are more closely related to lungfish and followed that line rather than that of the coelacanth. We humans also branched off that same line. The genome of a lungfish is composed of over 100 billion DNA letters, making it a much more difficult task to sequence, so for the time being, the coelacanth's DNA makes for a reasonable alternative for study.

"This is just the beginning of many analyses on what the coelacanth can teach us about the emergence of land vertebrates, including humans, and, combined with modern empirical approaches, can lend insights into the mechanisms that have contributed to major evolutionary innovations," said professor Chris Amemiya at the University of Washington, and the paper's co-author.

Fossil coelacanth: not much has changed in 350 million years.
Fossil coelacanth: not much has changed in 350 million years.Courtesy photo by Haplochromis via Wikipedia Creative Commons
When Louis Agassiz named the first fossil coelacanth back in 1836, the Swiss paleontologist probably never imagined that a nearly identical descendent of the primitively constructed Devonian-aged fish would one day be found still inhabiting the world's oceans. The coelacanth was thought to have gone extinct along with the non-avian dinosaurs at the end of the Cretaceous period. None have been found in the fossil record after that time, but two extant species are known today. The first specimen Latimeria chalumnae was netted off the coast of South Africa in 1938, near the Chalumnae river and retrieved by East London Museum curator Marjorie Courtenay-Latimer who discovered what she called "the most beautiful fish I'd ever seen" in the catch of local fisherman, Henrik Goosen. Since then several more coelacanths have been caught, including the Indonesian species, Latimeria menadoensis, from the Indian Ocean.

The remarkable prehistoric throw-back, sometimes referred to as "old four legs" because of its leg-like fins, hasn't changed much in its 350 million year history. A member of the clade of lobe-finned fishes called Sarcopterygii, coelacanths retain primitive characteristics such a notochord, a hollow fluid-filled tube made of cartilage that underlies the spine over the length of its body. In all other vertebrates, the notochord is an anatomical structure that appears briefly only during the embryonic stage but not in adults. Not so with the coelacanth. It also possesses, primitive shark-like intestines, a linear heart, and tightly-woven armor-like scales (known as cosmoid) that are only found on extinct species of fish. The coelacanth's brain case contains only 1.5 percent gray matter - the other 98.5 percent of space is filled with fat. The other end of the coelacanth body begins to taper before expanding into a strange, three-lobed tail. Its most notable features are its lobed pectoral and pelvic fins that are structured with bones that look like toes, and move in an alternating tetrapod manner. An electroreceptive rostal organ located in its snout is used to detect prey, and the coelacanth is the only living animal that can unhinge a section of the its cranium to increase the gape of its mouth, enabling it to consume larger prey.

The blue or brown, white-speckled coelacanths prefer deep-water environments, and can reach six and a half feet in length and weigh upwards to 175 pounds. For some reason no living coelacanth has managed to survive more than a single day in captivity. With a dwindling population estimated at only 500-1000 individuals, the coelacanth was declared an endangered species in 1989.

SOURCE and LINKS

Broad Institute news
Coelacanth info at dinofish.com
More coelacanth info
NatGeo article
Take Nova's Coelacanth Quiz

Apr
01
2013

Broccoli ice cream anyone?: Broccoli is just one of the new flavors of genetically modified ice cream now for sale. Through the GM process, 93 percent of calories have been removed from the new ice cream products.
Broccoli ice cream anyone?: Broccoli is just one of the new flavors of genetically modified ice cream now for sale. Through the GM process, 93 percent of calories have been removed from the new ice cream products.Courtesy Terence Ong
In one of the biggest breakthroughs in food and dietary history, the U.S. Food and Drug Administration has announced today (April 1, 2013), that it is permitting the sale of genetically modified ice cream to the public. The announcement comes on the heals of 16 years of experimenting and testing to come with a healthier version of the dairy food.

"Through the genetic modification (GM) process, we've been able to remove up to 93 percent of the calories you find in traditional ice creams, explained FDA spokesman Herman Guernsey. "And with that breakthrough, we've eliminated 100 percent of the guilt associated with eating ice cream. Now, people will be able to enjoy healthier and happier ice cream."

Of course, such breakthroughs also require some significant changes to the ice cream. The GM process did not work for traditional ice cream flavors like vanilla, chocolate or strawberry. "We did have to turn to some more health-oriented flavorings, but our focus groups seemed to especially like the GM ice cream flavors of broccoli, spinach and tuna," said Guernsey.

Cost is another issue for consumers. In order to push the GM ice cream through this advanced process, the cost right now is about $10 a pint. While public sales start today, GM ice cream may not be available in all grocery stores. But internet orders are being accepted at the website www.gmicecream.com. "We strongly advise anyone making internet orders do do so in the winter time as the ice cream is shipped by U.S. mail," Guernsey added.

He concluded: "We think people will enjoy this new GM ice cream and have a good laugh while reading this blog post."

Feb
25
2013

OMG! Can nothing stop them?: According to a new study, mosquitoes, those buzzing, biting, itch-producing flying pests that make life miserable for many of Earth's inhabitants (mainly we humans), can easily adapt to Deet, one of the commonly used ingredients in insect repellents.
OMG! Can nothing stop them?: According to a new study, mosquitoes, those buzzing, biting, itch-producing flying pests that make life miserable for many of Earth's inhabitants (mainly we humans), can easily adapt to Deet, one of the commonly used ingredients in insect repellents.Courtesy Mark Ryan (with photo help from NASA)

We've all seen them, those great B-films where a giant, vicious monster from under the sea, or invaders from outer space arrive to cause mayhem across our cities and generally mess up our way of life. In the end, it seems no matter who or what it was that was attacking us, be it Mothra, Godzilla, or some race of belligerent extra-terrestrials, we could always count on the military to save our collective behind.

Unfortunately, with mosquitoes, that might now be the case anymore.

Scientists are reporting that Deet, one of the most widely used active ingredients in insect repellents, loses its effectiveness against mosquitoes shortly after those ubiquitous, blood-seeking winged vermin are first exposed to it.

Deet - the common name for N,N-diethyl-meta-toluamide - was developed by the US Army after the Second World War to help combat insects during jungle warfare. It was used extensively in the Korean and Vietnam wars, but mosquitoes seem to be able to adapt quickly to it.

"Mosquitoes are very good at evolving very very quickly", said Dr. James Logan of the London School of Hygiene and Tropical Medicine and co-author of the study. "There is something about being exposed to the chemical that first time that changes their olfactory system - changes their sense of smell - and their ability to smell Deet, which makes it less effective."

So what I want to know is where does that leave us here in Minnesota where the mosquito constantly competes with the Common Loon for the title of State Bird? Maybe it's time to start digging the bunker in the backyard.

SOURCE and LINKS
BBC Science news
Original study at Plos One
The Life Cycle of the Mosquito
All about mosquitoes on NatGeo

Jan
31
2013

Home at last: Our late cat, Ernesto "El Gato Gordo" Hemingway, seen recuperating after somehow managing to find his way back home from across the street in 1997.
Home at last: Our late cat, Ernesto "El Gato Gordo" Hemingway, seen recuperating after somehow managing to find his way back home from across the street in 1997.Courtesy Mark Ryan
A cat in Florida got loose on one side of the state and managed to find its way back home to the other side, baffling both the delighted owners and scientists. Holly, the directionally-savvy 4-year-old tortoiseshell cat traveled from Daytona Beach to within a mile of her owners’ home in West Palm Beach. It took her about 50 days to traverse the 200 mile distance. When found, the poor kitty was weak and emaciated, had a croaky meow, and displayed signs of hoofing it over long distances.

“Her pads on her feet were bleeding,” said Bonnie Richter, who along with her husband, Jacob, are the happy owners (read: service staff) of the migratory feline. “Her claws are worn weird. The front ones are really sharp, the back ones worn down to nothing.

Skeptics might conjecture that the found cat is merely a stray that just looks like the long-lost Holly, and that the distraught owners only think it’s their cat because they miss her so and want to believe it’s her. Well, they couldn’t be more wrong. The scruffy cat in question had an implanted microchip that proves it is indeed Holly.

The Richters’ tale is but one of many incredible stories about lost or separated pets finding their way back home across vast distances. And surprisingly, science doesn’t seem to have any answers as how the animals do it.

“I really believe these stories, but they’re just hard to explain,” said Marc Bekoff, a behavioral ecologist at the University of Colorado. “Maybe being street-smart, maybe reading animal cues, maybe being able to read cars, maybe being a good hunter. I have no data for this.”

SOURCE
New York Times story

Jan
25
2013

Doubling up the double helix: The newly discovered quadruple helix in human DNA could lead to new treatments in cancer.
Doubling up the double helix: The newly discovered quadruple helix in human DNA could lead to new treatments in cancer.Courtesy rijksbandradio (original image) via Flckr; graphic by author.
By now most readers are aware of the double helix, the two intertwined ribbons of genetic information that make up our DNA.

Now researchers at University of Cambridge have announced the discovery of a quadruple helix in the human genome. The four-stranded genetic ribbons are termed G-quadruplexes because they contain high levels of the nucleotide guanine (the other 3 nucleotides are adenine, thymine, and cytosine – together they make up the G, A, T, and C elements of DNA; uracil (U) replaces thymine in RNA). G-quadruplexes mainly appear at the moment of cell replication, when cells divide and multiply. Researchers think this indicates that G-quadruplexes are an essential part of the replication process. The upsurge of G-quadrupleexes was detected using fluorescent biomarkers. The discovery could open up new avenues in the treatment of cancer

"The research indicates that quadruplexes are more likely to occur in genes of cells that are rapidly dividing, such as cancer cells,” said Shankar Balasubramanian, the study’s lead researcher. “For us, it strongly supports a new paradigm to be investigated -- using these four-stranded structures as targets for personalised treatments in the future."

Balasubramanian, a professor at the Department of Chemistry and Cambridge Research Institute, thinks synthetic molecules could one day be used to corral the G-quadruplexes and hinder the out-of-control cell division often prevalent in cancerous cells. In fact, the research team has already been successful in slowing down the replication process by using such molecules. During their experiments, when cell division was blocked, the number of G-quadruplexes decreased.

The research was published in Nature Chemistry. The 'quadruple helix' discovery comes 60 years after the discovery of the double helix in 1953, also at the University of Cambridge.

SOURCES and LINKS
Wired
Science Daily

Jan
24
2013

Sniffing Out Cancer: Amherst chemists develop a way to "smell" cancer cells.
Sniffing Out Cancer: Amherst chemists develop a way to "smell" cancer cells.Courtesy Jeremie63
Chemists from the University of Massachusetts Amherst have developed a way to quickly and accurately detect and identify metastatic cancer cells in living tissue, in much the same way that your nose can detect and identify certain odors.

The smell of a rose, for example, is a unique pattern of molecules, which activates a certain set of receptors in your nose. When these specific receptors are triggered, your brain immediately recognizes it as a rose.

Similarly, each type of cancer has a unique pattern to the proteins that make up its cells. The Amherst chemists just needed a "nose" to recognize these patterns. What they came up with was an array of gold nanoparticle sensors, coupled with green fluorescent proteins (GFP). The researchers took healthy tissue and tumor samples from mice, and trained the nanoparticle-GFP sensors to recognize the bad cells, and for the GFP to fluoresce in the presence of metastatic tissues.

This method is really sensitive to subtle differences, it's quick (can detect cancer cells within minutes), it can differentiate between types of cancers, and is minimally invasive. The researchers haven't tested this method on human tissue samples yet, but it holds some exciting potential.

Jan
11
2013

Nano at home!: Forget those super-sterile clean rooms.  The DIY Nano app lets you explore nanoscale science in the comfort of your own home!
Nano at home!: Forget those super-sterile clean rooms. The DIY Nano app lets you explore nanoscale science in the comfort of your own home!Courtesy NISE Network
When things get really really small (nanoscale small), they behave completely differently! For example, gold at the nanoscale can look purple, orange, or red; static electricity has a greater effect on nanoparticles than gravity; and aluminum (the stuff your benign soda cans are made of) is explosive at the nanoscale!

If you want to experience some of these nanoscale phenomena first-hand, check out whatisnano.org, or download the DIY Nano app. The website and the app were both created by the Nanoscale Informal Science Education Network (NISE Net for short), and have videos and activity guides, complete with instructions and material lists, so you can do some nano experiments at home! The app was a Parents' Choice award winner for 2012, and was featured in Wired Magazine's review of apps. Definitely worth a look!

Have fun exploring nanoscale properties!

Jan
07
2013

A white-throated sparrow: Is its tweeting music to the ears other birds?
A white-throated sparrow: Is its tweeting music to the ears other birds?Courtesy Dave Govoni (Va bene!)
Is birdsong music? Does the tweeting and chirping of our feathered friends elicit the same emotional response in them as one of Chopin’s nocturnes does in us? Do they serve the same purpose? These are questions that have long been argued in scientific circles and elsewhere.

A new study published recently in Frontiers of Evolutionary Neuroscience shows some interesting results in how birds perceive birdsong.

Researcher Sarah Earp and neuroscientist Donna Maney, both of Emory University looked at brain imaging data gathered from studies of human neural responses to music and compared them with similar data from birdsong studies.

Some of the white-throated sparrows were given a boost of hormones (testosterone and estradiol) that made them all a-twitter and ready for love. When a male sparrow stepped up to the microphone and started serenading, the females showed a definite response.

“We found that the same neural reward system is activated in female birds in the breeding state that are listening to male birdsong, and in people listening to music that they like,” said Sarah Earp.

But what was music to the ears of the female sparrows was perceived by their male counterparts as discordant (and probably very annoying) noise from a rival suitor. An awkward third-wheel sort of deal, I suppose.

“Birdsong is a signal,” said Maney. “And the definition of a signal is that it elicits a response in the receiver. Previous studies hadn’t approached the question from that angle, and it’s an important one.”

The females in the sample group showed increased activity in the same region of their bird brains that humans display in their corresponding region when hearing a piece of music they enjoy. The response of the control group females - those not in a breeding state and without any hormonal boost - showed little response to song. Male sparrows treated with testosterone showed an amygdala response not unlike how the human brain responds to scary movie music.*

The brain’s mesolimbic reward pathway has counterparts in both humans and birds. In humans it lies beneath the cerebrum and is involved in emotions, memory, and olfaction. A neurotransmitter called dopamine is produced within the brain’s limbic system and spreads along the limbic pathways to help regulate the brain’s reward and pleasure centers. The chemical messenger also governs movement and emotions.

The study shows that not only does birdsong and music produce similar responses in corresponding brain regions linked to reward but also in areas thought to regulate emotions. And the response also seems to connected to social context in both birds and humans.

“Both birdsong and music elicit responses not only in brain regions associated directly with reward, but also in interconnected regions that are thought to regulate emotion,” Earp said. “That suggests that they both may activate evolutionarily ancient mechanisms that are necessary for reproduction and survival.”

LINKS
Emory University story
Frontiers of Evolutionary Neuroscience
More about dopamine
The intelligence of birds

*Rather than scary, I find composer Bernard Herrmann’s musical score used in Alfred Hitchcock’s PSYCHO very compelling – not sure what that response means. But it’s interesting to note that Herrmann’s music in the movie was also a big influence on record producer George Martin’s string arrangement for the Beatles’ melancholy ballad ELEANOR RIGBY.