If bacteria can’t grow in a Petri dish, sequencing them is difficult.
What’s the News: Want the genome of a bacterium you found in your belly button? Or, for that matter, of a bacterium producing a promising new antibiotic? Well, unless you can get it to thrive in a Petri dish and create a billion sister cells for analysis, you’re out of luck.
But sequencing the genomes of notoriously finicky bacteria, like those on skin, could be on the horizon with a new procedure that bypasses the Petri dish step. Pairing a new algorithm with an earlier technique, scientists from the Venter Institute and their collaborators can now get all that information from a single cell.
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What’s the News: Among the many creepy denizens of Australia—such as the red back spider, seen here hauling a lizard into its nest, and the saltwater crocodile, which kills with its distinctive “death roll”—the assassin bug is right at home. With its erratic, long-legged walk, it stalks along spiders’ webs, caressing its prey with its antennae and then stabbing them with its beak. Now, scientists who spy on these spider-eaters report that the bugs have yet another charming behavior in their toolkit: using the breeze as cover when they go in for the kill.
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With only seven northern white rhinos left in the world, creating eggs and sperm from stem cells offers the possibility of salvaging some of the species.
What’s the News: In an effort to help preserve endangered rhinos and primates, biologists have converted skin cells taken from the animals into pluripotent stem cells, which can grow into nearly anything, given the right conditions. They might even grow into egg and sperm cells, eventually, the researchers think, suggesting a cell biological route to conservation.
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What’s the News: Researchers have now found a well-preserved fossil of the earliest known member of the animal group that encompasses today’s placental mammals, which includes humans. The shrew-like creature, named Juramaia sinensis, or “Jurassic mother from China,” dates back to 160 million years ago, 35 million years earlier than the oldest mammal fossil previously discovered. The Nature study gives some tangible support to genetic evidence suggesting that the two main types of mammals split well before the previous oldest mammal fossils.
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Three-dimensional model of an ancient whale skull.
What’s the News: Scientists have long held that archaeocetes, the precursors to modern cetaceans, had symmetrical skulls like most other mammals. Whale skulls only became asymmetrical as certain species evolved echolocation to hunt for food. But it turns out that archaeocetes actually had skewed skulls, which likely allowed the whales to hear better underwater, according a new study published in the journal PNAS.
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A cluster of 3.4 billion-year-old fossilized cells
What’s the News: Geologists have found fossils of microorganisms from 3.4 billion years ago, which may be the oldest fossils ever uncovered. Since these microbes date from a time when Earth’s atmosphere was still oxygen-free, astrobiologists could look for similarly structured microbes when searching for extraterrestrial life.
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Elkhorn coral infected with white pox.
What’s the News: Over the past decade, diseases, pollution, and warming waters have put coral populations across the globe in a dramatic decline. In an extreme case, the population of elkhorn coral, considered one of the most important reef-building corals in the Caribbean, has decreased by 90–95 percent since 1980, partly due to a disease called white pox.
Now, scientists have traced this lethal disease back to humans. Human feces, which seep into the Florida Keys and the Caribbean from leaky septic tanks, transmit a white pox-causing bacterium to elkhorn coral, researchers report in the journal PLoS ONE. “It is the first time ever that a human disease has been shown to kill an invertebrate,” ecologist James Porter told Livescience. “This is unusual because we humans usually get disease from wildlife, and this is the other way around.”
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What’s the News: Biologists have discovered an eel so bizarre that they didn’t initially know if it was an eel or some other kind of fish. The strange creature, dubbed Protoanguilla palau after a researcher found it in an undersea cavern off the coast of Palau, has very few of the anatomic features of modern eels, but displays many hallmarks of primitive eels from the Mesozoic era. It appears that the eel’s last common ancestor with any other living creature existed 200 million years ago, the researchers report in the journal Proceedings of the Royal Society B.
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Heliconius numata (top) mimics the wing
pattern of Melinaea mneme (bottom).
What’s the News: A single species of butterfly in the Amazon is able to copy the wing patterns of several neighboring species to avoid being eaten by hungry birds—a wide-ranging talent that has long perplexed evolutionary biologists. Now, an international team of scientists studying the mimicking butterfly Heliconius numata has finally solved this puzzle that plagued even Charles Darwin.
Writing in the journal Nature, researchers found that a specific supergene—a cluster of genes that is passed on to offspring as one big chunk—controls the different elements of wing patterns, allowing related butterflies to display distinct markings despite having the same DNA. “These butterflies are the ‘transformers’ of the insect world,” lead researcher Mathieu Joron said in a prepared statement. “But instead of being able to turn from a car into a robot with the flick of switch, a single genetic switch allows these insects to morph into several different mimetic forms.”
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Reindeer are joining the select club of animals known to see ultraviolet light. Hanging about the UV-baked upper latitudes has made their special vision advantageous, since their favorite food, lichen, and their least favorite neighbor on the tundra, wolves, both absorb the light, scientists say. With the UV reflecting off snow all around, both their food and their enemies stand out. While this is a pretty rare talent among mammals, once upon a time, more of us could see the rays, reports Scientific American:
UV vision actually has deep roots in the mammalian family tree: hundreds of millions of years ago early mammals had a short-wave-sensitive visual receptor, called SWS1, that could detect UV rays. That sensitivity is thought to have shifted toward longer waves—away from short UV wavelengths—because mammals were mainly nocturnal and UV vision was of little use to them at night. This shared ancestral UV sensitivity may explain why a small yet diverse set of mammals has regained the ability to see UV light.
Read the rest at Scientific American.
Image credit: Tristanf / flickr
Scientists have now sequenced the genome of the Atlantic cod, revealing something unusual: the cod is missing an important component of the adaptive immune system found in almost all jawed vertebrates. In particular, when the researchers compared the cod’s genome to that of the stickleback (a closely related fish that has already been sequenced), they saw that the Atlantic cod does not have genes that code for the proteins MHC II, CD4, and invariant chain, all of which work together to help the body recognize and fight off invading bacteria and parasites.
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What’s the News: In the squid world, the body size of male spear squid determines the mating strategies they use. Small male squid, which have no chance of physically competing with their larger rivals, must try to get with the females of the species on the sly. Now, researchers in Tokyo have learned that this difference in mating behavior has resulted in the evolution of divergent sperm types, though perhaps not in the way you’d think: diminutive male squid actually produce larger sperm than big male squid.
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Researchers at Wake Forest University in North Carolina have now learned that Nazca boobies perpetuate a “cycle of violence”: bullied chicks tend to become bullies and pass on the pain. When parent birds leave their nests to eat, baby boobies are often visited by sexually and physically abusive non-breeding adults; the chicks, when grown, are more likely to abuse unrelated chicks. “The link we found indicates that nestling experience, and not genetics, influences adult behaviour,” lead researcher David Anderson told BBC.
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What’s the News: Trouble sticking to your diet? It may not be entirely your fault. Scientists, reporting in the journal Cell Metabolism, have now learned that when you starve yourself of calories, your brain cells also starve, causing your neurons to begin eating parts of themselves for energy. The self-cannibalism, in turn, cranks up hunger signals. This mouse study may lead to better treatments for human obesity and diabetes.
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Richard Branson’s Virgin Oceanic sub is poised to be the first of this new fleet of commercial subs to start probing the depths—it should launch this year.
The deepest point in the ocean, the bottom of the Marianas Trench off the coast of Guam, is the scene of a new kind of space race: a deep-sea submarine race, undertaken by such private investors as director James Cameron, Virgin Group mogul Richard Branson, and Google executive chairman Eric Schmidt. Citing the excitement of exploration, all are involved in the construction of next-generation submersibles to plumb the trench and other deeps, taking advantage of price reductions in many components and the dearth of such innovation in the scientific community. Though designed to take the builders and other thrill-seekers to incredible depths, the ships are by and large not intended to be one-shot wonders, William J. Broad of the NYTimes reports:
“It’s not a publicity stunt,” [one builder] said of the planning effort. “We’re commercial vehicle builders. We want a product that can be used repeatedly without any difficulty — one that is very elegant, very safe and very competitive.”
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