Stories tagged Life Science

Oct
27
2014

Antler wrestling: Two young bull elk compete in Estes Park, Colorado.
Antler wrestling: Two young bull elk compete in Estes Park, Colorado.Courtesy Mark Ryan
Each autumn, Rocky Mountain elk or wapiti (Cervus canadensis) migrate into Estes Park valley in Colorado for their annual mating season (also known as "the rut" or "rutting period"). During our three day visit last month, my wife and I saw them everywhere - in the meadows near the entrance to Rocky Mountain National Park (RMNP); in Lake Estes; cooling off under the pines; and all over the city golf course (which was closed due to their presence). One night, while coming out of the downtown grocery store parking lot, we nearly hit three of them standing in the middle of the street!

We were staying about two blocks up from Lake Estes, and the morning of our last day I walked down the hill to take video of any elk I could find. I wasn't disappointed. As I made my way toward the lake, a couple of large bulls were prodding a harem of about 25 females through a residential area and onto the town golf course. As the video shows, the sight of so many of these massive beasts is both fascinating and intimidating.

Except for moose, elk are the largest members of the deer family (in Europe elk are called moose). Elk harems usually consist of several females (cows) - and sometimes calves - which, during mating season, are controlled and watched over by one or two bulls. Other opportunistic males will gather around the harem's periphery waiting to challenge the dominant bull or for a chance to hook up with a stray female.

The poor dominant male - in this case, a bull with a 14-point antler rack - spent most of his time trying to find a receptive female or fending off his rivals. It's a tireless job. Males shed and regrow their antlers each year. The rack turns to solid bone by the end of the summer and can weigh up to 40 pounds.

What surprised me most was the elk's bugling call. It's a high pitch wail often followed by a series of quick chirps. Sometimes, it reminded me of squawking seagulls for some reason. Of all ungulates­, elk are definitely the noisiest.

Bull elk use bugling to attract females and to warn rivals. The bulls will display their dominance in several ways, one of which is by raising their head high to show off their antlers. This posturing is usually sufficient, but sometimes two males will engage in antler wrestling to determine who's dominant of the two. Bulls will also dig up the ground with their antlers and front hooves and roll around in their urine to add a cow-attracting scent to themselves. You can observe some of their behaviors in video.

I think what I saw and recorded took place near the end of the pre-rut. There was no mating that I witnessed (except for a calf going through the motions with its mother!). The bulls seemed eager enough but the cows weren't quite in estrus (heat), and wanted nothing to do with their suitors. The estrus cycle of a female elk is short-lived and lasts only one or two days. When it does happen, the bulls are ready to mate several times during the cycle.

Elk get agitated and dangerous during the rut. There are warnings posted around Estes Park and RMNP about getting too close or having your pets with you when observing them. I unintentionally got between two bulls which could have turned into a nasty situation. But, fortunately, it didn't.

LINKS
Elk facts
More elk rut footage shot by Estes Park news team
Elk in Estes Park story in NYT
More elk info

Oct
13
2014

Nobel Prize
Nobel PrizeCourtesy Photograph: Jonathunder Medal: Erik Lindberg (1873-1966)
This past week a Nobel Prize in chemistry was awarded to three scientists for finding ways to use fluorescent molecules that glow on demand to allow scientists to peer into living cells. Using beams of laser light, an area is scanned multiple times making the molecules glow; images are then super-imposed to yield an image at the nanoscale.

The ground-breaking work by these three scientists brought optical microscopy into the nano dimension. Previously, the limit of optical microscopes was presumed to be roughly half the wavelength of light (0.2 micrometers).

The Royal Swedish Academy of Sciences when announcing the award, stated,

"In what has become known as nanoscopy, scientists visualize the pathways of individual molecules inside living cells. They can see how molecules create synapses between nerve cells in the brain; they can track proteins involved in Parkinson’s, Alzheimer’s and Huntington’s diseases as they aggregate; they follow individual proteins in fertilized eggs as these divide into embryos.

Two separate principles are rewarded. One enables the method stimulated emission depletion (STED) microscopy, developed by Stefan Hell in 2000. Two laser beams are utilized; one stimulates fluorescent molecules to glow, another cancels out all fluorescence except for that in a nanometre-sized volume. Scanning over the sample, nanometre for nanometre, yields an image with a resolution better than Abbe’s stipulated limit.

Eric Betzig and William Moerner, working separately, laid the foundation for the second method, single-molecule microscopy. The method relies upon the possibility to turn the fluorescence of individual molecules on and off. Scientists image the same area multiple times, letting just a few interspersed molecules glow each time. Superimposing these images yields a dense super-image resolved at the nanolevel. In 2006 Eric Betzig utilized this method for the first time.

Today, nanoscopy is used world-wide and new knowledge of greatest benefit to mankind is produced on a daily basis."

The three winners are:
1) Eric Betzig, U.S. citizen. Born 1960 in Ann Arbor, MI, USA.
Ph.D. 1988 from Cornell University, Ithaca, NY, USA.
Group Leader at Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
http://janelia.org/lab/betzig-lab

2) Stefan W. Hell, German citizen. Born 1962 in Arad, Romania.
Ph.D. 1990 from the University of Heidelberg, Germany.
Director at the Max Planck Institute for Biophysical Chemistry, Göttingen, and Division head at the German Cancer Research Center, Heidelberg, Germany.
http://www3.mpibpc.mpg.de/groups/hell

3) William E. Moerner, U.S. citizen. Born 1953 in Pleasanton, CA, USA.
Ph.D. 1982 from Cornell University, Ithaca, NY, USA.
Harry S. Mosher Professor in Chemistry and Professor, by courtesy, of Applied Physics at Stanford University, Stanford, CA, USA.
http://web.stanford.edu/group/moerner

To learn more about this research visit:

2014 Nobel Prize in Chemistry - Periodic Table of Videos

See video

The Nobel Prize announcement:
http://www.nobelprize.org/nobel_prizes/chemistry/

Background about the limit of optical microscopes known as Abbes' Diffraction Limit (0.2 μm)
http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2014/popular-...

To learn more about nanotechnology, science, and engineering, visit:
www.whatisnano.org

To see other nano stories on Science Buzz tagged #nano visit:
http://www.sciencebuzz.org/buzz_tags/nano

Sep
27
2014

Edwards' Dodo: painted by Roelant Savery in 1626
Edwards' Dodo: painted by Roelant Savery in 1626Courtesy Public domain via Wikipedia
Death of individuals is a fact of life, and in the same way so is extinction of species. An animal species lasts, on average, about 4 million years. It's claimed that 99 percent (or more!) of all species that have ever lived on Earth are now extinct. (If you are wondering how that number was calculated, you can read a couple explanations here).

The statistic becomes more credible when you consider this interesting image compilation of every animal that's gone extinct in just the last 100 years. The death list includes not only all sorts of birds and fish, but rhinos, hippos, deer, bi-valves, bison, horses, geckos, frogs, bats, lions, tigers, and bears - oh, my! (Because of its vastness the insect world is not included in the list).

Most of the life-forms pictured have been confirmed as extinct by the International Union for the Conservation of Nature (IUCN) along with a few others from reliable sources. That's not to say some straggling thought-to-be-gone individuals won't be sighted in some obscure location in the future but until then they'll be considered extinct.

The compilation not only gives a good picture of the diversity of life on our planet but also a good idea of the fragility of the biosphere.

SOURCE and LINKS
Every animal that have gone extinct in the last century on Pixable.com.
Endangered Species International
Center for Biological Diversity

Sep
12
2014

Paleontologist Ernst Stromer: Discoverer of original Spinosaurus aegyptiacus.
Paleontologist Ernst Stromer: Discoverer of original Spinosaurus aegyptiacus.Courtesy Public domain via Wikipedia
Back in 1911, German paleontologist Ernst Stromer discovered and described the remains of a then new Cretaceous dinosaur he named Spinosaurus aegyptiacus. The strange beast sported a huge sail framed around a series of giant spines that ran down its back. Unfortunately, all Stromer's fossil evidence was destroyed during the hostilities of WW II, when the British Royal Air Force bombed the Munich museum where the fossils were stored. Only a few scientific drawings and a single photograph remain.

Ninety years later an international team of researchers led by paleontologist Nizar Ibrahim returned to Stromer's original dig site and discovered additional specimens of Spinosaurus aegyptiacus, and in studying their fossils have come to some startling new conclusions about the strange dinosaur.

Spinosaurus aegyptiacus
Spinosaurus aegyptiacusCourtesy University of Chicago Fossil Lab
Spinosaurus was a big boy - nine feet longer than the largest known Tyrannosaurus rex. And despite a long-held notion that dinosaurs were strictly terrestrial - i.e. they only dwelled on land (although like us, they probably occasionally swam in water), S. aegyptiacus appears to have spent much of his life in water, feeding on fish, and when on land (e.g to lay eggs) probably walked on all-fours, unlike every other known predatory dinosaur.

The new findings are published online on the Science Express website, and in the October issue of National Geographic.

Paul Sereno, vertebrate paleontologist at the University of Chicago and a member of the research team, explains some of the new knowledge gleaned from the newly discovered fossil bones.

SOURCES and LINKS
University of Chicago report
Science Daily story

Aug
18
2014

Hallucigenia sparsa fossil: from the Burgess Shale
Hallucigenia sparsa fossil: from the Burgess ShaleCourtesy M. R. Smith / Smithsonian Institute
One of the strangest and more mysterious critters that scurried across the Middle Cambrian seafloor has baffled paleontologist since it was first identified in the 1970s. Was it a worm? Which side was up? Did it have legs or spikes or both? Was its head actually its tail? Did it have any extant descendents or was it an evolutionary dead-end? The worm-like creature was so baffling and so bizarre, it was given the very apropos name of Hallucigenia.

The tubular, spiked-worm possessed seven or eight pairs of legs and ranged in length from 2/5th of an inch to one and 1/4 inches and looks like something out of a bad dream. Early interpretations of their fossils were all over the map. The stiff spikes on it back were first thought to be its legs, and its legs misidentified as tentacles. What was thought to be its tail ended up being its head.

Using modern imaging technology, researchers from the University of Cambridge have been closely studying fossils from the famous Burgess Shale quarry located high in the Canadian Rockies, and are uncovering Hallucigenia's secrets. By studying the claws at the end of its legs they have been able to link it to modern velvet worms (onychophorans). Scientists have long suspected the two were somehow related but until now have failed to find anything significant to prove it. By studying Hallucigenia's claws they've determined that they're constructed of nested cuticle layers, very similar to how the jaws of velvet worms are organized. The similarity is no surprise since jaws are known to have evolved from a modified set of front legs.

But besides giving Hallucigenia a place in the lineage of life on Earth, the Cambridge team during the course of their study also discovered something else: that arthropods - which include crustaceans, spiders, insects and trilobites - aren't in fact as closely related to velvet worms as previously thought.

“Most gene-based studies suggest that arthropods and velvet worms are closely related to each other," said co-author Dr Javier Ortega-Hernandez. "However, our results indicate that arthropods are actually closer to water bears, or tardigrades, a group of hardy microscopic animals best known for being able to survive the vacuum of space and sub-zero temperatures – leaving velvet worms as distant cousins.”

SOURCE and LINKS

University of Cambridge story
Previous Buzz Post on Hallucigenia
The Cambrian Explosion
More about Tartigrade

Jun
02
2014

Drosophila melanogaster: the fly.
Drosophila melanogaster: the fly.Courtesy André Karwath aka Aka via Wikipedia Creative Commons
FlyMAD could be the best thing since sliced bread. The thermo- and opto- genetic device, created by team of scientists from the Research Institute of Molecular Pathology (IMP) at Vienna University and a US lab, allows the researchers to focus visible light and heat rays onto specific regions in a fly's anatomy and manipulate the annoying insect's behavior.

Using lasers and computers, the tool can precisely target and activate certain neurons in the thorax and brain of the fruit fly Drosophila melanogaster raising its temperature and stirring up its courtship behaviors. In one test, the fly began "singing" (through rapid wing vibration) as it hit on various balls of wax. Another test turned the pesky bug into the King of Plop causing it to switch into courtship dance mode (they had one doing the moonwalk!) What's wild is that FlyMAD performed these manipulations while the erratic test subjects were on the move inside an enclosed box.

The science team, led by biologist Andrew Straw and his lab, documented the test results with video recordings, and published their findings in the journal Nature Methods.

The name FlyMAD, by the way, stands for "Fly Mind Altering Device". Can you think of a cooler name than that? Maybe this could lead to the building of a better fly-swatter.

SOURCE and LINKS

ScienceDaily.com
Straw Lab Blog
Vienna Biocenter story

Apr
17
2014

Virus Filter - The fibers of the filter are white and the virus green.
Virus Filter - The fibers of the filter are white and the virus green.Courtesy Björn Syse

Scientists have developed a paper made of cellulose nanofibers that can be used to filter out harmful viruses.

The new filter paper is made with cellulose fibers, a natural component of green plants that gives wood its strength. Cellulose is the main component of plant cell walls, and the basic building block for many textiles and for paper. Cellulose works well for filters because it is inexpensive, disposable, inert, and non-toxic; cellulose is also mechanically strong and stable in a wide range of acid and alkaline conditions.

But normal filter paper can't trap viruses. A virus is tiny, about a thousand times smaller than a human hair. Normal filter paper has pores that are too large to remove tiny viruses. The new nano fiber filter paper is made with cellulose fibers with diameters of less than 100 nanometers. Viruses range in size from 30-50 nanometers, and can be trapped in the nano fiber filter paper.

The research has been conducted at two Swedish universities, Uppsala University and Swedish University of Agricultural Sciences/Swedish National Veterinary Institute.

To read more about this research visit:
http://www.uu.se/en/media/press-release-document/?id=2271&area=3,8&typ=p...

To learn more about nanotechnology, science, and engineering, visit:
www.whatisnano.org

To see other nano stories on Science Buzz tagged #nano visit:
http://www.sciencebuzz.org/buzz_tags/nano

Apr
13
2014

Tiktaalik roseae: Field Museum of Natural History
Tiktaalik roseae: Field Museum of Natural HistoryCourtesy Eduard Solà via Wikipedia
If you missed last week's PBS broadcast of Your Inner Fish, the documentary based on paleontologist-anatomist Neil Shubin's book by the same name, you have another chance to catch up on the first of three segments on the web. It's an excellent opening segment of the 3-part series, but is only available (for free!) right here through April 23, 2014.

The series deals with Shubin's search for the connections we all have with our fishy and reptilian ancestors. His discovery of the remarkable transitional fossil named Tiktaalik roseae on Ellesmere Island in the Canadian Arctic has added great evidence of our ties with our distant piscean relatives. The flat-headed, 375 million year-old Tiktaalik possessed the exact features - such as both lungs and gills, a wrist and neck - that you'd hope to find in a transitional form between swimming fish and land-walking tetrapods.

The next episode, titled Your Inner Reptile airs Wednesday, April 16th on your local PBS station. It's on here in the Twin Cities at 9pm but check your local listing for times in your area.

In the meantime, watch the first episode, and read about some of the reaction to Shubin's find here, here, and here.

LINKS
University of Chicago Tiktaalik roseae page

Mar
05
2014

Virus: Giant viruses are genetically more complex and about 25 percent larger.
Virus: Giant viruses are genetically more complex and about 25 percent larger.Courtesy jiparis
A husband-and-wife-led research team has announced finding an ancient virus laying dormant in Siberian permafrost for more than 30,000 years!

Jean-Michel Claverie and Chantal Abergel of Aix-Marseille University in France and their colleagues cut up pieces of permafrost samples - supplied by scientists from the Russian Academy of Science - and added them to petri dishes of amoebae only to see the one-celled animals ripped apart by unknown viruses. They isolated the attacking, larger-than-usual virus and named it Pithovirus sibericum, because of its resemblance to an earthenware jar. The permafrost samples had been collected from a frozen riverbank in Siberia in 2000.

The discovery brings the total number of known "giant viruses" to three. The extra-large viruses are about 25 percent larger than normal, genetically more complex, and composed of hardier stock.

"Among known viruses, the giant viruses tend to be very tough, almost impossible to break open," said Claverie and Abergel. "Special environments such as deep ocean sediments and permafrost are very good preservers of microbes because they are cold, anoxic and in the dark."

Two other giant viruses Mimivirus and Pandoravirus were also discovered by Claverle and Abergel in the last decade. The latter, in my opinion, is a disturbingly great name for this type of thing. But so far only the pithovirus has been observed in the laboratory infecting contemporary life forms. Luckily, none of them pose a threat to humans, but that's not to say future giant viruses thawed out of frozen environments or released by retreating ice caps won't be.

"I don't see why they wouldn't be able to survive under the same conditions," said Claverie.

Results of the research appear in the Proceedings of the National Academy of Sciences.

SOURCES and LINKS
National Geographic story
Sydney Morning Herald
More about giant viruses

Feb
21
2014

Is obesity in this baby's future?: It could depend on the yogurt's fat content.
Is obesity in this baby's future?: It could depend on the yogurt's fat content.Courtesy Clover_1
Last Christmas, my son's girlfriend introduced me to honey-flavored yogurt, a delicious concoction of creamy sweetness. I've never been a fan of yogurt, but I immediately fell in love with this stuff, and try to keep a container of it on-hand in the fridge at all times. I can't seem to get enough of it.

One of the reasons it's so tasty is because it's made with whole milk which makes it high in fat, and therefore will make anyone who ingests it high in fat, too. Right? Maybe not.

Two new studies seem to point to just the opposite. Several middle-aged men who participated in a Swedish study and consumed high-fat dairy products, were tracked over a 12 year period and showed much less propensity of becoming obese when compared to men who followed a low or no high-fat diet in the same study. The research appeared in the journal Scandinavian Journal of Primary Health Care.

In the second study involving the meta-analysis of 16 empirical studies showed that - despite working under the hypothesis that a diet of high-fat foods leads to higher heart disease risk and contributes to obesity - no evidence supporting the claim was found. Actually, according to the study which appeared in the European Journal of Nutrition, consumption of high-fat dairy products were instead associated with a lower obesity risk.

Non-fat and low-fat yogurts still command a larger portion of the market but on the organic side of the things products with higher saturated fat content is, surprisingly, on the upswing. It's unclear why that is. A previous study involving children also showed that a low-fat diet was more likely to lead to obesity.

"There may be bio-active substances in the milk fat that may be altering our metabolism in a way that helps us utilize the fat and burn it for energy, rather than storing it in our bodies," said Greg Miller, of the National Dairy Council.

Besides the newly associated weight benefits, whole organic milk also contains higher levels of omega-3 fatty acids which help reduce the risk of cardiovascular diseases. It's also speculated that consumption of higher fat content may lead to a greater and faster feeling of being satisfied and full, and lead to a sooner cessation of the urge to eat.

For purely scientific reasons I'll be heading for the refrigerator in a moment to see if that's the case.

SOURCE
NPR story