Stories tagged Life Science

Nov
04
2010

You think you’re safe from the dangers of the wild just because you live in a city? This video will change your view. It was shot by a guy named Craig Kuberski, who lives within the city limits of St. Paul, MN. I know some of you were hoping you'd get to see a rogue cougar or bear mauling innocent urbanites or eating their pets, but that’s not the case here. It’s just a couple of bucks on the town and in a rut trying to catch some city girls' attention.

Rutting period is the mating season for many ruminants, (i.e. mammals like moose, caribou, bison, and deer). The rut is set-off by the shortening of daylight hours during autumn and in the case of white-tail deer (Odocoileus virginianus - which I’m pretty sure these are) can last for one to three months. During that time, male deer get all goofy and twitterpated, rubbing their antlers against trees, rolling in the dirt or mud, or battling each other – as seen in this video. Rutting season is the best time to hunt for them, and the easiest time to hit them with your car, although I don’t advise you do the latter.

As you may notice, Mr. Kubinski posted two buck fever videos on YouTube. I’ve only used the second here because it’s the better of the two, focus-wise, But if you’d also like to watch Part I, there you have it. KARE 11 also ran a story on it.

Nov
04
2010

Disease Detectives
Disease DetectivesCourtesy Disease Detectives
Earlier this year I got the chance to work as the crew of high school staff in the Kitty Andersen Youth Science Center (http://www.smm.org/kaysc/) at the museum to create a series of web-based videos about infectious diseases for the Disease Detectives exhibit. We worked from January through August learning video production skills, learning about different infectious disease topics, talking to experts and folks on the museum floor. We're just getting the videos online now, and all of our videos will be on the exhibit website soon (www.diseasedetectives.org) but I wanted to share them here as well.

For this video, titled "Got Beef? The Story Behind Antibiotics and Livestock" the crew to a slaughter house on in South St. Paul, the Minnesota Department of Health, U of M St. Paul (at 7AM to see the cows grazing), Mississippi Market Co-op, and did hours of research, prep, and post production.
Got Beef? The Story Behind Antibiotics and Livestock from Disease Detectives on Vimeo.

You can check out the video here.

Oct
15
2010
It's Friday, so it's time for a new Science Friday video. Science Friday
Science Friday
Courtesy Science Friday
Today,
"Reporting in the journal Science, Paul Kubes and colleagues filmed immune cells called neutrophils finding their way to a mouse's wounded liver. The researchers wanted to understand how neutrophils find injuries when bacteria aren't around to signal the damage."
Oct
05
2010

Normal human brain: Well, okay maybe Abby Normal is a better description. It is my brain after all. I had a recent MRI and was really glad to see I had something other than rocks in my head.
Normal human brain: Well, okay maybe Abby Normal is a better description. It is my brain after all. I had a recent MRI and was really glad to see I had something other than rocks in my head.Courtesy Mark Ryan
A new study appearing in the Journal of Palliative Medicine reports how several terminally ill patients all showed identical surges in their brain activity just before they died. At first the doctors at George Washington University Medical Faculty Associates who did the study thought the surge was being caused by interference from life-support machines or other electronic gear in the room.

“But then we started removing things, turning off cell phones and machines, and we saw it was still happening,” said lead author Lakhmir Chawla.

Speculation of what causes the neurological hyperactivity at the moment of death is that neurons in the brain, suddenly deprived of blood pressure and oxygen, shut down in rapid succession resulting in a final burst of neural activity - an electrical death rattle if you will. But the idea doesn’t seem to be a very new one. Kevin Nelson, a researcher studying near-death experiences at the University of Kentucky claims it’s well known that the brain experiences a sudden discharge of electrical energy when blood flow to it is cut off.

So, I’m not sure I see what the big surprise is here. If this is so well-known then why wouldn’t the doctors at George Washington University Medical Associates already know this?

But there’s another part of this that’s interesting. The surge may also be responsible for the "white light" reported by some patients who have had near-death episodes. The lore surrounding this phenomenon is about patients seeing an intense bright light when they're dying. But, according to Chawla, the majority of people involved in such incidents report having no such “white light” occurrence, but merely a vivid memory that may have been burned into their brain by the “final” electrical discharge.

And what about the so-called "out of body experience" patients sometimes report after slipping from the grasp of the Grim Reaper? Well, that, too, could come from the brain's electrical shutdown. A study that appeared in the journal Nature in 2006 reported patients sensing "shadow figures" laying nearby, or hovering above while certain areas of their brains were being stimulated with electrical currents. The charges interfered with the sensory information being received by the brain, and the hallucinations were just the brain's way of making senses of everythingl. The New York Times ran a story about it you can read here.

Bottom line, it looks like all those reported supernatural near-death experiences are just all in your head.

SOURCES
Discovery News story
International Association for Near-Death Studies website

Sep
22
2010

Newly discovered wood-eating catfish: held by Paulo Petry.
Newly discovered wood-eating catfish: held by Paulo Petry.Courtesy Paulo Petry via the Nature Conservancy
If catfish are your thing (and why wouldn't they be?) then you'll be happy to learn about a new species of wood-eating catfish that's been discovered in the confluence of the Purus and Curanja rivers in Peru. Local people (Nahua) have been eating the armored catfish for a while but until now the only specimens scientists have seen were dried carcasses. That changed recently when researchers led by freshwater scientist Paulo Petry finally caught some live ones. I'm happy to report as one would expect, it is one ugly creature. The fish (which ranges from 12 to 25 inches in length) has a mouthful of specialized spoon-shaped teeth perfect for stripping wood from trees that have fallen into its river habitat. Very kissable as you can see here. Even though it ingests the wood, it doesn't digest it. The nutrients contained in the wood are absorbed in the fish's gut and the wood itself is excreted as waste.

This new species has yet to be described and remains unnamed but is included in the genus Panaque, to which all wood-eating catfish belong. More info and an interview with researcher Paulo Petry can be found on the Nature Conservancy blog.

Sep
22
2010

Salmonella invades human cells: Color-enhanced scanning electron micrograph showing Salmonella typhimurium (red) invading cultured human cells.
Salmonella invades human cells: Color-enhanced scanning electron micrograph showing Salmonella typhimurium (red) invading cultured human cells.Courtesy Rocky Mountain Laboratories,NIAID,NIH
More than half a billion eggs were recalled after Salmonella sickened over 1600 people (according to the Center for Disease Control, or CDC in September.) That’s a lot of eggs, and a lot of sick people.

What is this nasty bacteria that makes us wonder whether we should let our kids eat raw chocolate chip cookie dough, even as we sneak several spoonfuls when they’re not looking?

Salmonella enterocolitis is one of the most common types of food poisoning and is caused by the bacteria Salmonella Enteriditis. You can get a Salmonella infection by swallowing food or water that is contaminated with the salmonella bacteria. Often, the culprit is surface contamination from raw chicken and raw or undercooked eggs. In most people, it causes diarrhea, fever and abdominal cramping, but young children and those with weakened immune systems are at greater risk of dehydration and more serious infections.

Why don’t they just wash the eggs better? Salmonella bacteria live in the intestinal tracts of animals and birds and can infect the ovaries of healthy-looking chickens. This allows bacteria to infect the eggs even before the shell is formed and voila- you have a pathogen that can’t be washed off of the egg because it’s inside. Salmonella bacteria are often found in the “white” of an egg, although they can migrate to the yolk as the raw egg sits in your refrigerator. Organic and free range chickens have less disease than factory-”farm” raised chickens, partly because of healthier diets and less crowding. Cooking eggs until the yolk is solid kills Salmonella bacteria.

How can you make your cookie dough and eat it too? Buy pasteurized eggs (you can find them at most grocery stores) that have been heat-treated to kill bacteria, but are still essentially raw for all cooking and baking purposes.

Also, remember to wash cutting boards you’ve cut meat on with soap and water before cutting anything else on them, or just have separate cutting boards for meat. Don’t forget to wash your hands after handling raw eggs! Pet food and reptiles can also harbor salmonella bacteria, so have your kids wash their hand after handling either!

Bacteria are everywhere. Some keep you healthy and some make you sick, but making good decisions in the kitchen can keep you and your family from being affected by food-born illness!

(This blog post was originally posted on the Kitchen Pantry Scientist blog.)

Sep
10
2010

Dear Tooth Fairy: You can't handle the tooth! (At least not if a new research idea becomes popular)
Dear Tooth Fairy: You can't handle the tooth! (At least not if a new research idea becomes popular)Courtesy Rev Dan Catt
A new study just published in the Journal of Biological Chemistry says our third molars - aka wisdom teeth - could serve as an excellent source for stem cells. Rather than yanking them out and discarding them (often under our pillows), the molars could be kept as a repository of stem cells for our own use in regenerative medicine. The Japanese study, which was led by Yasuaki Oda, states cloned cells derived from wisdom teeth closely resemble embryonic stem cells.

It sounds like wise use of what's otherwise considered medical waste, but don't be surprised if the Tooth Fairies' Union says it bites.

Aug
28
2010

T-rex could run, but he couldn't hide: More than one asteroid impact may have wiped out non-avian dinosaurs.
T-rex could run, but he couldn't hide: More than one asteroid impact may have wiped out non-avian dinosaurs.Courtesy Mark Ryan
The meteor that created the Chicxulub Crater in Mexico's Yucatan Peninsula may have not been the only one responsible for the extinction of non-avian dinosaurs 65 million years ago. "Fern spike" evidence in another similarly-aged crater found in the Ukraine indicates at least two large impacts took place within a few thousand years of each other. Concentrations of fern spores are commonly found in the mud that fills in impact craters. The Boltysh Crater contains two layers of spores within three feet of each other, indicating not one but two impacts.

"We interpret this second layer as the aftermath of the Chicxulub impact", said Simon Kelley, co-author of the study, and professor of Isotope Geochemistry at the Open University.

Both the Chicxulub and Boltysh bolide events could have been part of a meteor shower that hit Earth at the end of the Cretaceous. The study appears in the journal Geology.

SOURCE and INFO LINKS
BBC story
The K-T Extinction event

Aug
13
2010
It's Friday, so it's time for a new Science Friday video. Science Friday
Science Friday
Courtesy Science Friday
Today:
"Plants have a reputation for staying put. But some plants are moving so quickly, we can't see their motions. Biologist Joan Edwards and physicist Dwight Whitaker broke out the high-speed cameras to capture the story of exploding peat moss. The research was published in the journal Science."
Aug
07
2010

Close-up of fossilized dinosaur bone: Notice the amazing level of preservation displayed by the vascular system inside the bone.
Close-up of fossilized dinosaur bone: Notice the amazing level of preservation displayed by the vascular system inside the bone.Courtesy Mark Ryan
A recent study published in the journal Palaios raises new questions about the role of bacteria in the process of fossilization of bone material. In tests simulating rapid burial and groundwater percolation, researchers Joseph Daniel and Karen Chin set up four different groundwater environments where chunks of bone were placed in river sand and water, laden with calcium carbonate, was allowed to flow through it for three months. In one test the environment was left untreated allowing for bacteria in the sediment to grow naturally. In two other tests the simulated environment was sterilized using antiseptics that either reduced or eliminated completely the naturally growing bacteria. For the fourth test, Chin and Daniel washed and treated the sediment with bleach then reseeded it with the natural bacteria.

The samples were monitored closely, and after just one week, the scientists noticed mineral precipitants had already begun to attach sand grains to the bone fragments in both the nonsterile tests, but saw no change in the sterile environment samples.

After three months, the results showed that the cubes of bone soaked in the natural, untreated environment had begun to show signs of permineralization, and some of the bacteria even showed early signs of lithification. As before, the fragments in the sterile environment were unchanged and appeared as fresh as new bone.

This is pretty amazing, because I was always under the impression that in order to become a fossil, the remains of an animal had to be buried rather quickly so as to remove them from the destructive elements of nature. But it looks like some of nature’s tiniest elements are necessary to the process.

This study could also help explain how, after 68 million years, organic material managed to remain essentially unchanged (or actually less-permineralized) deep inside the fossilized femur of a Tyrannosaurus rex, such as that discovered a few years back by paleontologist Mary Schweitzer (Read about it here).

Karen Chin, by the way, specializes in the study of fossil feces (coprolites), and participated in a 2001 study also published in Palaios documenting the role of bacteria in the fossilization of herbivore dinosaur droppings.

SOURCES
Abstract of Chin and Daniel study in PALAIOS
Story at Smithsonian.com