- ID Error Leaves Fish at Edge of Extinction
- Plants Have a Social Life Too
- Mummy Scans Show Heart Disease Was Rampant
- Russian Cosmonaut’s Blog Much Funnier Than NASA
- Hubble Detects Galactic X-File
Posted: 18 Nov 2009 01:46 PM PST
In an extinction scenario that might have been concocted by Douglas Adams or a taxonomically-minded Kafka, a classification error has allowed fishermen to drive a species of skate to near-oblivion.
If it vanishes, the flapper skate will be the first fish officially exterminated by commercial pressures — and for the last 83 years, it wasn't even considered a species.
In 1926, biologist R.S. Clark declared that the flapper skate, formally known as Dipturis intermedia, and the blue skate, or Dipturus flossada, were actually the same animal. His classification was widely accepted, and the two species were lumped together as the common skate.
But when French Museum of Natural History biologist Samuel Iglesias decided to review Clark's assessment, he noticed that common skates often look quite different. Genetic analysis backed up his suspicions: Clark was wrong. The flapper skate and blue skate really are different species. And that means trouble, because overfishing had already pushed the common skate to critically endangered status — a prognosis that now seems optimistic.
Instead, continued reports of rare common skate catches have obscured the flapper skate's even-nearer-total collapse. According to Iglesias, whose analysis will be published in an upcoming issue of Aquatic Conservation: Marine and Freshwater Ecosystems, immediate action is necessary to save the flapper skate.
Otherwise it will go extinct, soon — and if it wasn't for Iglesias, nobody would have known.
Citation: "Taxonomic confusion and market mislabelling of threatened skates: important consequences for their conservation status." By Iglésias S.P., Toulhoat L., Sellos D.Y.. Aquatic Conservation: Marine and Freshwater Ecosystems, in press.
Posted: 18 Nov 2009 12:16 PM PST
After decades of seeing plants as passive recipients of fate, scientists have found them capable of behaviors once thought unique to animals. Some plants even appear to be social, favoring family while pushing strangers from the neighborhood.
Research into plant sociality is still young, with many questions unanswered. But it may change how people conceive of the floral world, and provide new ways of raising productivity on Earth's maxed-out farmlands.
"When I was in school, researchers assumed that some plants were better or worse than others at getting resources, but they were blind to the whole social situation," said Susan Dudley, a McMaster University biologist. "I went looking for it, and to my shock, found it. And we've found more of it since."
In a paper published in the November American Journal of Botany, Dudley describes how Impatiens pallida, a common flowering plant, devotes less energy than usual to growing roots when surrounded by relatives. In the presence of genetically unrelated Impatiens, individuals grow their roots as fast as they can.
Acknowledging relatives in this way is an example of kin recognition. It's common in the animal world, and is a precursor to kin selection, in which animals help their familial group, not just themselves. Dudley thinks plants have kin selection, too. It's a controversial idea, but that it's even being debated shows how far research into plant sociality has come.
When Dudley was in school in the 1980s, the very idea of plant sociality was practically taboo among scientists. It had burst into popular consciousness a decade earlier with the publication of The Secret Life of Plants, a New Age classic which also discussed orgones and dowsing. Later studies on "talking trees" went unreplicated, and the idea fell into disrepute.
But even if full-blown sentience was a silly idea, research on plant communication gathered. Much of it described how plants defended themselves, producing toxins and concentrating resources on their immune systems when unrelated neighboring plants were eaten. That clearly involved some sort of chemical signaling. Further studies conclusively showed plants were able to recognize themselves. Whether plants might respond to their relatives became a legitimate and intriguing question.
The answer isn't only of concern to people with imaginations stirred by thoughts of chatting flora. It could provide a whole new perspective on plant behavior and evolution. By providing insights that improve agricultural productivity, studies of kin recognition could literally bear fruit.
"We know that in the animal world, kin recognition and selection plays a very important role for family structure, altruistic behavior and those kinds of things," said Hans de Kroon, a plant ecologist at Radboud University in the Netherlands. "It's so prominent in the animal literature. Once we start to discover that plants can recognize their kin, there's a whole set of hypotheses we can apply to studying plants, that nobody ever thought to."
The field's landmark paper came from Dudley's laboratory in 2007, when she showed how American searocket plants accelerated their root growth when placed in pots of strangers, but slowed it down when potted with siblings. Were they animals, they'd be described as sharing water and food.
In a Communicative and Integrative Biology paper published in October, University of Delaware biologists Harsh Bais and Meredith Biedrzycki tried to isolate the means of recognition by exposing Arabidopsis thaliana seedlings, each in its own pot, to root secretions from other Arabidopsis plants. The signal indeed proved to be in the roots — and just as Dudley had seen, growth patterns varied according to whether secretions came from genetically unrelated plants, or family.
Intriguingly, the plants in Dudley's latest study were potted separately and unexposed to each others' secretions, suggesting that their leaves emit chemical signals, as well as their roots. That's supported by the research of University of California, Davis ecologist Richard Karban, who in a June Ecology Letters study showed that sagebrush boosts its immune system when exposed to the damaged cuttings of a related plant [pdf]. It seems to hear warnings from its kin.
More studies are needed to show exactly what sort of benefits are provided by these signaling and response systems. De Kroon said kin recognition doesn't necessarily mean kin selection: maybe the plants are communicating, but it doesn't do them much good in practice.
One of Dudley's students, Amanda File, is now studying whether some trees favor their own progeny, which might grow best near their parents. Dudley and graduate student Guillermo Murphy, a co-author of the American Journal of Botany paper, are looking for for kin selection in invasive plants.
"We're testing the hypothesis that invasive plants evolve greater altruism within their populations, allowing them to be better invaders of their new habitats," said Dudley.
For plants used in agriculture, Dudley recommends kin recognition studies to see whether certain arrangements of relatives and strangers would be especially productive. De Kroon is looking at multi-species mixes. Karban hopes to use communication insights to engineer natural defense systems against pests.
"Maybe we thought before that only humans could do certain things, or vertebrates, or animals," said Karban. "Plants are capable of much more sophisticated behavior than we assumed."
Images: 1) Mustard seedlings exposed to root secretions/Harsh Bais. 2) Impatiens seedlings grown next to relatives and strangers/Susan Dudley.
Posted: 18 Nov 2009 10:56 AM PST
ORLANDO, Florida — The curse of the mummy may truly be fatal. An examination of mummified bodies has revealed that ancient Egyptians suffered from hardening of the arteries in surprising frequency, suggesting that blame for heart disease extends beyond the modern culprits of smoking, fast food and the remote control.
Among 22 mummies who received full-body computed tomography scans, 16 had hearts or arteries preserved enough to study. Of those, nine had evidence of blockage from atherosclerosis. "This disease has been around since before the time of Moses," said Randall Thompson of the St. Luke's Mid America Heart Institute in Kansas City. Thompson and colleagues presented their findings Nov. 17 at the American Heart Association's Scientific Sessions 2009. The data were also published in the Nov. 18 Journal of the American Medical Association.
Although researchers have previously taken X-rays and other images of famous mummies, "no one has ever put a series of ancient people through modern CT scans," Thompson said. The mummies, from the Museum of Antiquities in Cairo, ranged from 2,000 to 3,500 years old. All were selected by museum staff, who chose the most intact bodies from different spans of time. On a CT scan, the buildup of fat, cholesterol, calcium and other substances inside artery walls looks as distinct for the dead as the living.
The scientists decided to conduct the study after two of the research team members — Gregory Thomas of the University of California, Irvine and Adel Allam of the Al Azhar Medical School in Cairo — visited the museum in 2008. They noticed that the nameplate for Merenptah, who ruled around 1200 B.C., claimed the pharaoh had suffered from atherosclerosis. Curious to know whether this was true, the doctors gathered a research team to determine the prevalence of heart disease among the preserved representatives of an ancient, upper-class civilization. Funding came from Siemens, the National Bank of Egypt and the Mid America Heart Institute.
In Orlando, the scientists reported the consequences of all those fatted calves: Among the eight people in the sample who had lived past the age of 45, seven had signs of clogged arteries. The most ancient mummy to have suffered from heart disease was Lady Rai, a nursemaid to Queen Amrose Nefertari. She died around 1530 B.C. while she was in her 30s, though her cause of death is not known.
"We would have thought this was a disease of modern man," said Samuel Wann of the Wisconsin Heart Hospital in Wauwatosa and a study team member. The results, he said, are bound to stoke an ongoing controversy among cardiologists. "We have a debate among our colleagues whether atherosclerosis is inevitable if you live long enough," he said.
The findings should not be taken to mean that modern risk factors have no bearing on heart disease, said Robert Bonow, chief of cardiology at Northwestern University's Feinberg School of Medicine. The mummies studied would have had diets high in salt (for food preservation) and would have enjoyed the pampered lifestyle of the wealthy, so even these ancient people may have had risk factors like those of modern people, said Bonow, who was not part of the research team.
"This does not tell you what the true incidence was," he said at the meeting. "Patients should not take this as evidence that they shouldn't worry about preventing heart disease because it's been around a long time."
Image: Michael Miyamoto/UC San Diego
Posted: 18 Nov 2009 10:10 AM PST
It's not just NASA that's hip to the social media game anymore. Now, the Russian space agency Roscosmos has one of its own blogging from the International Space Station.
The blog, as translated by Russia Today, includes pictures from the ISS — and covers a much different array of topics than you usually see in NASA press releases or Twitter feeds. A recent post detailed the "holy symbols" in the Russian area of the station, illustrated by photos of icons and crucifixes floating in zero gravity.
"We have four holy icons on the Russia segment. We also have the gospels and a big cross," wrote Maksim Suraev. "And I have a reliquary cross in my cabin. A priest gave it to me at Baikanur before the launch. Father Job told me a piece of the original cross on which Jesus was crucified is contained in mine."
Not exactly what you'd find NASA astronauts like Mike Massimino writing about, and that's exactly what makes the reflections worth reading. We tend to receive our vision of space exploration through the American lens, so it's great to get some outside perspective on what's going on up there. And Suraev's site really feels like someone's blog.
He even injects some dark, faux Cold-War humor into his writing. Take, for example, his description of the photo above.
"In the photo I'm holding the latest gadget developed by our military. The device works in two modes. One allows eavesdropping on our colleagues in the American segment. You can … record all their conversations. Also, the device can be used for martial arts training — to be prepared for an alien attack on the Russian segment of the ISS," he wrote last week. "Guys, it's just a joke, I hope you realize! It's not some weapon or a spy gadget. Just an old pump that Roma and I replaced!"
If you read Russian, you can check out the original Roscosmos postings.
Posted: 18 Nov 2009 09:58 AM PST
This photo from the Hubble Space Telescope reveals a strange, faint "X" shape extending from the center of the spiral galaxy NGC 4710.
Spiral galaxies are named for the arms curling outward from a central core of stars and gas. All of them have some sort of bulge at the center, but some, perhaps 20 or 30 percent, have this strange type of boxy or peanut-shaped bulge. (Astronomers sometimes even abbreviate this shape as B/PS.) The mysterious structures can only be observed when looking edge-on at the galaxy.
How and why such shapes develop is a matter of dispute in the astronomical community. One theory holds that they formed early in the galaxy's history before its arms and structure were well-defined. Other astronomers propose that the bulges develop throughout the galaxy's existence, slowly building up. Various mechanisms for distributing matter in this way have been proposed, too.
NGC 4710 is located in the Virgo Cluster of galaxies. It's located 60 million light-years away in a lesser-known northern constellation which bears the strange name, Coma Berenices, translated as the "Hair of Queen Berenice."
Image: NASA & ESA.
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