Category Archives: Life Science

2007 Nobel Prize in Physiology or Medicine

Nobel Prize in Physiology or Medicine 2007 awarded to Mario R. Capecchi, Martin J. Evans and Oliver Smithies for their discoveries of “principles for introducing specific gene modifications in mice by the use of embryonic stem cells”

This year’s Nobel Laureates have made a series of ground-breaking discoveries concerning embryonic stem cells and DNA recombination in mammals. Their discoveries led to the creation of an immensely powerful technology referred to as gene targeting in mice. It is now being applied to virtually all areas of biomedicine – from basic research to the development of new therapies.

Gene targeting is often used to inactivate single genes. Such gene “knockout” experiments have elucidated the roles of numerous genes in embryonic development, adult physiology, aging and disease. To date, more than ten thousand mouse genes (approximately half of the genes in the mammalian genome) have been knocked out. Ongoing international efforts will make “knockout mice” for all genes available within the near future.

Mario R. Capecchi, born 1937 in Italy, US citizen, PhD in Biophysics 1967, Harvard University, Cambridge, MA, USA. Howard Hughes Medical Institute Investigator and Distinguished Professor of Human Genetics and Biology at the University of Utah, Salt Lake City, UT, USA.

Sir Martin J. Evans, born 1941 in Great Britain, British citizen, PhD in Anatomy and Embryology 1969, University College, London, UK. Director of the School of Biosciences and Professor of Mammalian Genetics, Cardiff University, UK.

Oliver Smithies, born 1925 in Great Britain, US citizen, PhD in Biochemistry 1951, Oxford University, UK. Excellence Professor of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, NC, USA.

The USA gains 2 Nobel Laureates born elsewhere – the incidence of this happening 30 years from now will be less I believe than it has been recently.

Mammoth DNA Extracted from Hair

Mammoth DNA extracted from hair reveals ancient secrets

The woolly mammoth hair had been so well preserved that it provided the most accurate DNA sequencing of the extinct animals yet achieved. One of the animals used in the study dated back 50,000 years and its hairs allowed scientists to obtain the oldest complete sequence of mitochondrial DNA.

Three mammoths had been subjected previously to DNA sequencing, two with bone fragments and the third with a sample of muscle tissue.

Results from hair assessed using the sequencing-by-synthesis (SBS) technique were more detailed than bone and muscle samples. Importantly, said researchers, the SBS extraction technique required smaller quantities of ancient material and caused less damage to the preserved specimens.

Mammoths roamed the landscape for about six million years and their disappearance about 10,000 years ago – with a handful of dwarf mammoths surviving on remote Siberian islands until little more than 2,000 years ago – has remained a mystery.

Rare Chinese Mountain Cat

rare photo of Chinese mountain cat in the wild.jpg

Rare Chinese Cat Captured on Film

Triggered by body heat, a remote camera recently captured this image of the elusive Chinese mountain cat at about 12,300 feet (3,750 meters) on the edge of the Tibetan Plateau in China’s Sichuan Province. A total of eight images of the feline represent the first time the mountain cat has been photographed in the wild, said Jim Sanderson, a cat specialist with the Wildlife Conservation Network who led the team that snapped the rare shots. A paper about the cat will appear in an upcoming issue of the journal Science.
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“There’s no interest in its conservation because it’s poorly known, but now perhaps this will change.”

I am biased by my love of cats but I hope this helps conservation efforts.

Finding Protease Inhibitors

Can’t Cut This by Kathleen M. Wong, ScienceMatters@Berkeley:

When a malaria parasite lands in your blood, one of the first things it does is whip out its scissors. As fast as it can, this protozoan snips the hemoglobin in red blood cells to get the nutrients it needs to survive. Of course, the microbe behind this deadly disease doesn’t actually deploy stainless-steel blades. Instead, it uses an array of biochemical scissors known as proteases.

Proteases are enzymes that snip proteins. They recognize certain strings of amino acids on a substrate protein, bind to this area, then break a nearby chemical bond. Proteases can destroy proteins by snipping them in half, as in malaria. They can also activate proteins by lopping off atoms covering a reactive site.

This versatility has made proteases critical to all manner of organisms, from viruses to plants to humans. Over the past 10 years, protease inhibitor drugs have become indispensable in the fight against AIDS, cardiovascular disease and diabetes. But finding protease inhibitors is no picnic. Humans manufacture tens of thousands of proteins; figuring out which of these a protease targets is extremely challenging and time consuming.
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Instead of mixing liquid chemicals and painstakingly purifying them again at each step, he attaches his precursor molecules to polystyrene beads resembling sand grains.

Scores Ill in Peru after Meteor Strike

Scores ill in Peru ‘meteor crash’

Some 600 people in Peru have required treatment after an object from space – said to be a meteorite – plummeted to Earth in a remote area, officials say. They say the object left a deep crater after crashing down over the weekend near the town of Carancas in the Andes.

People who have visited scene have been complaining of headaches, vomiting and nausea after inhaling gases. A team of scientists is on its way to the site to collect samples and verify whether it was indeed a meteorite.
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The object then hit the ground, leaving a 30m (98ft) wide and 6m (20ft) deep crater. The crater spewed what officials described as fetid, noxious gases. The gases are believed to have affected the health of about 600 people who visited the site.

Blocking Bacteria From Passing Genes to Other Bacteria

Scientists are working on many fronts to keep deadly bacteria in check

Bacteria that cause cholera and bubonic plague turn from harmless to deadly with the flip of a genetic switch. Jam the switch and you might prevent infection, said Vladimir Svetlov, a microbiology research associate at Ohio State University and one of a group of scientists who defined the structure of a protein that appears to be the key. The discovery is one of many this year to identify structures and chemicals crucial to disease. All of this work could lead to new medicines.

At the same time, germs we once fought off with antibiotics are fighting back, forcing governments and health organizations worldwide to spend billions of dollars to find new remedies.
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Redinbo is part of a team that recently discovered that two osteoporosis drugs block a key site on E. coli bacteria, preventing it from passing antibiotic resistance genes to other E. coli.

By their nature, bacteria exchange pieces of their DNA with neighboring bacteria, leading to new forms that are virulent or resistant — or both. “This is not minor evolution,” said Irina Artsimovitch, associate professor of microbiology at Ohio State. “This is a huge genome exchange.”

Very cool stuff. Related: Antibiotic resistance: How do antibiotics kill bacteria? – Disrupting the Replication of Bacteria – Antibiotics Too Often Prescribed for Sinus Woes – Attacking Bacterial Walls

Thousands of Spiders Build Huge Web

Thousands of spiders worked together to build huge web (site broke link so I removed it) by Anna Tinsley:

But Tuesday afternoon, thousands of Texas spiders were back at it, working to rebuild an immense spider web at Lake Tawakoni State Park that at one time stretched about 200 yards, covering bushes and trees to create a creepy canopy.

Researchers say they now believe thousands of spiders from different species worked together to make one huge web — much different from the traditional individual webs that would normally be woven. Together, they’ve built and rebuilt a web that has caught countless bugs and the attention of people nationwide. “These spiders seem to be working together to build it back,” said Zach Lewis, an office clerk at the park. “It’s really something to see.
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“It looked just like a spider would have jumped from tree to tree with a can of silly string.” Researchers say it likely took 1 1/2 to two months to weave such a large web.
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He found spiders from 12 families, with the most prevalent being from the Tetragnathidae family. Identified spiders were funnel web weavers, sac spiders, orb weavers, mesh web weavers, wolf spiders, pirate spiders, jumping spiders and long-jawed orb weavers, according to the researchers’ report.
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“With the amount of rain that has occurred this year and the huge food supply available, it just created the right condition for all of this,” he said. “It’s possible we’ll see it again. But this happened to be a year where the conditions were right.”

Fun in Nature: Polar Bear and Wolves

Fun slides on American Public Media: Stuart Brown describes Norbert Rosing’s striking images of a wild polar bear playing with sled dogs in the wilds of Canada’s Hudson Bay.

Virus Found to be One Likely Factor in Bee Colony Collapse Disorder

Photo of a bee bu Justin Hunter

Scientists say a virus appears to be a factor in honeybee colony collapse by Andrew C. Revkin:

Scientists sifting genetic material from thriving and ailing bee colonies say a virus appears to be a prime suspect – but is unlikely to be the only culprit – in the mass die-offs of honeybees reported last autumn and winter.

Very well stated. The virus while seeming to be a factor in the deaths appears to cause death in colonies that are stressed which seem to be highly correlated with colonies that are moved from place to place by commercial beekeepers to pollinate various crops. Bees that are kept by hobbiest, wild bees… don’t seem to be dying off. The impact of CCD is growing economically as prices for renting bees to pollinate crops increases and in some cases there are not enough bees available. Honey prices are increasing and prices for food pollinated by bees are too.

The Department of Agriculture states: The only pathogen found in almost all samples from honey bee colonies with CCD, but not in non-CCD colonies, was the Israeli acute paralysis virus (IAPV), a dicistrovirus that can be transmitted by the varroa mite. It was found in 96.1 percent of the CCD-bee samples. This does not identify IAPV as the cause of CCD,” said Pettis. “What we have found is strictly a strong correlation of the appearance of IAPV and CCD together. We have not proven a cause-and-effect connection.”

Related: Bee researchers close in on Colony Collapse Disorder, Penn State (Penn State broke the link so it was removed) – Bye Bye Bees – Bee Colony Collapse Disorder CCD – More on Disappearing Honeybees – Colony Collapse Disorder and Pollinator Decline

Clues to Prion Infectivity

Structural Studies Reveal New Clues to Prion Infectivity

One of the unexplained questions facing prion researchers is how a single prion can apparently assume different conformations — with each conformation having different disease or phenotypic properties. Previous structural studies of prions had not yielded a clear understanding of the basis of strains because the prion protein is large and complex. Due to the size and complexity of prions, studies utilizing x-ray crystallography, a technique commonly used to determine the structure of proteins and other molecules, have been limited to short peptide fragments of the prion protein.

“There have been a number of fairly low-resolution pictures of prions that more or less proved that these different strains were in different conformations; but they really hadn’t established the nature of the different conformations,” Weissman said. “It was really a big black box. We basically didn’t have the conformation of any single prion, let alone the two prion protein strains in two different conformations.”
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““In our minds, our findings brought to a certain level of closure the understanding of the structural differences underlying strains,” said Weissman. “Now we understand the structural differences. We also have an idea how those differences lead to the differences in physical properties, and, in turn, how these differences in the physical properties lead to the phenotypic differences. We are starting to go all the way from the structural understanding of the different strains up to in vivo understanding of why they cause different behaviors inside the cell.”

Weissman noted that the findings offer a broader lesson to researchers studying prions and other proteins whose misfolding can cause disease. “Certainly, a bottom line from this study is that the rules of protein folding and the rules of protein misfolding are fundamentally different,” he said. “In many ways, we have to relearn basic principles of how proteins misfold. We have to forget many of the rules we learned from textbooks about protein folding because they are not necessarily applicable.”

Prions are very interesting. Related posts: Scientists Knock-out Prion Gene in Cows – Gene Study Finds Cannibal Pattern – Open Access Education Materials on Protein Folding