ScienceShot: How Spider Assassins Mimic Prey

Sometimes the spider becomes the prey. At least when assassin bug Stenolemus bituberus is on the job. The spindly-legged insect (pictured) lures arachnids to their deaths by landing on webs, struggling like entangled prey, and then

eating the arachnids for dinner. To figure out how the deception works, scientists placed spider webs in a sound chamber and recorded the vibrations when an assassin bug, a falling leaf, a courting male spider, or one of two types of prey (vinegar fly or aphid) touched the web. Spiders' reactions to the assassins most closely mirrored those toward prey: turning, pausing, and approaching 65% of the time and turning but not approaching 35% of the time. However, the spiders never aggressively approached the assassin bugs, the researchers report online today in the Proceedings of the Royal Society B. The scientists think this reflects a deliberate tactic of the assassins. By making only short, low-frequency vibrations, the predators mimicked the struggles of small or exhausted prey, duping the spiders into letting down their guard.

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Mouse-Sized Primates Shed Light on Human Origins

Tiny primate teeth discovered in the Sahara Desert may illuminate our own humble beginnings as creatures the size of mice. The 39-million-year-old fossils belong to a subgroup of primates known as anthropoids, which includes monkeys,


apes, and humans. Researchers say the find indicates that our ancient ancestors were entrenched in Africa earlier than expected and that they didn't begin to get larger until well after they had moved to Africa and adapted to new environments there.
Researchers once thought that the first anthropoids arose in Africa. That's because for many years the earliest fossils of universally accepted anthropoids came from 37-million-year-old fossil beds in the Fayum region of Egypt. But over the past 16 years, scientists have discovered tiny primates in Asia that many think are the earliest known anthropoids, such as the 45-million-year-old Eosimias from Myanmar, says paleontologist Christopher Beard of the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.
Now, in three field seasons in central Libya, Beard and an international team of paleontologists have learned more about when these higher order primates reached Africa, possibly from Asia, and diversified. They discovered teeth from three completely different groups of anthropoids: Afrotarsiidae (which now includes Old World monkeys such as macaques), Parapithecidae (extinct primates also known from the Fayum region of Egypt), and Oligopithecidae (primates from the Fayum that gave rise to some Old World and New World monkeys). Other kinds of animal fossils suggest that the site is between 38 million and 39 million years old, as does paleomagnetic dating, which relies on a pattern of well-dated reversals in Earth's magnetic field recorded in sediments.
If the date is correct, it would suggest that anthropoids left Asia soon after they arose there about 45 million years ago and dispersed to Africa and other parts of the globe much earlier than expected, says team leader and paleontologist Jean-Jacques Jaeger of the University of Poitiers in France. "Our goal is to nail down when these anthropoids got into Africa," adds Beard. An alternate view is that these tiny anthropoids arose in Africa instead of Asia, allowing enough time for them to evolve the diversity seen in these fossils from Libya. The team reports its find online today in Nature.
Although the identification of several of the fossils as early anthropoids is solid, not everyone is convinced that their age is accurate. Paleontologist Erik Seiffert of Stony Brook University in New York thinks that several of the fossils are so similar to those he and others have found in Egypt that they might be roughly the same age of 37 million years or younger—and thus not evidence for an earlier presence of anthropoids in Africa.
Paleontologist Richard Kay of Duke University in Durham, North Carolina, notes, however, that the Libyan fossils are smaller than those in Egypt, suggesting that they may indeed be older and more primitive. Their small size and other features, Jaeger says, also link the Libyan fossils to the earliest anthropoids in Asia—but not to Ida, a 47-million-year-old fossil primate from Germany whose discoverers controversially proposed her as an ancestor of anthropoids.
Only after the first wee primates migrated out of Asia and scooted rapidly to new habitats in Africa did some anthropoids begin to get larger and start evolving down the path toward becoming apes—and, eventually, humans, he thinks. "If this migration to Africa had not occurred, the anthropoid might have become extinct in Asia and we would not be here," Jaeger says.

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Did 'Snowball Earths' Trigger Animal Evolution?

For heavy-breathing animals like us, Earth was unlivable for most of its history. Only when oxygen filled the air and dissolved in the ocean more than half a billion years ago was the door opened to the evolution of animals much more active than a sponge. Now researchers may have found a surprising trigger for the rise of


animals: globe-girdling ice ages that threatened to wipe out all life on Earth.
Biogeochemist Noah Planavsky of Woods Hole Oceanographic Institution in Massachusetts and his colleagues report online today in Nature finding a possible link between the "snowball Earth" glaciations—episodes in which ice encased or nearly encased the planet—and the rise of life-energizing oxygen more than 500 million years ago. They measured the phosphorus content of iron-rich minerals formed in ancient oceans as a gauge of the phosphorus content of seawater. During the past 3 billion years, phosphorus abundance varied little, they found, with one exception: a surge to levels several times higher than usual lasting from about 750 million years ago to about 635 million years ago.
A phosphorus surge at that time would fit nicely into an emerging scenario for animal evolution. Researchers have noted that two snowball-Earth episodes roughly coincided with the appearance of the earliest animals in the fossil record. That suggested that the glaciations triggered the evolutionary leap, but how?
In the scheme offered by Planavsky and his colleagues, the snowball ice sheets would, as their modern counterparts do, grind up continental rock that would release phosphorus when the glaciers retreated. That phosphorus would wash into the ocean, where it would fertilize algal blooms that could drive a surge in the production of organic matter and oxygen. And the added organic matter that settled into the mud on the ocean bottom would leave additional oxygen behind, eventually boosting atmospheric and oceanic oxygen.
An apparent glitch in that story is phosphorus's short lifetime in the ocean. According to one view, ice on a snowball Earth retreated only once, at the end of a 10-million-year-long glaciation. That would produce an ephemeral phosphorus pulse incapable of influencing evolution. But co-author and biogeochemist Timothy Lyons of the University of California, Riverside, says that even a single snowball Earth event could have produced elevated phosphorus concentrations, as ice sheets repeatedly advance and retreat during a snowball episode.
A phosphorus link between glaciations and oxygen, and therefore evolution, "is a fascinating possibility," says biogeochemist Donald Canfield of the University of Southern Denmark in Odense. "But they don't yet have the continuous [geologic] record that would prove it. In principle, it's a testable hypothesis; that's the work's value."

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Hellish 'Super-Earths' Likely Prevalent Throughout Our Galaxy

 

 Planet hunter. The Earth-orbiting, French-built COROT space telescope has been looking for the transits of certain Earth-like planets since 2006.

Although it's only a little bigger than Earth and is made of the same ingredients, this planet is no paradise. It orbits so close to its parent star that its surface is a sea of molten lava, its atmosphere swirling with silicate vapor.
The galaxy is rife with hellish worlds like this one, astronomers now predict based on theoretical studies.


New findings suggest that Earth-like planets are common throughout the galaxy. However, when Kevin Schlaufman, a graduate student at the University of California, Santa Cruz, and colleagues used computer models to simulate a theoretical extrasolar planet population, they found that a new breed of super-Earths was also surprisingly prevalent. The team's results, to be published in The Astrophysical Journal Letters, indicate that these rocky planets would range up to 10 times the mass of Earth and would orbit their host stars in 24 hours or less, as does the planet described here.
"If our model and analysis are correct, these very hot super-Earths would be the hottest planets in the galaxy," says Schlaufman. "Their surfaces would likely be oceans of lava, possibly in the process of being vaporized by their own stars."
Such planets typically form early in the history of a solar system and are farther away from their stars than Earth is from the sun. So how does an Earth-mass planet end up so close to its parent star? The short answer is via inward migration. Over about 100,000 years, the planets interact with their surrounding, gas-rich planetary disks, causing their orbits to swiftly move inward toward their parent stars. Schlaufman notes that life on these scorching planets is totally out of the question.
Natalie Batalha, the deputy science team lead for NASA's Kepler mission to find Earth-like worlds, says that Kepler's detection of many planetary candidates smaller than Neptune in close orbits around their stars suggests that Schlaufman and colleagues' models "might be right on target." And the project is expected to announce the discovery of a slew of such hot super-Earths by early next year.
"Such super-Earths would be different from anything in our solar system," said Eric Ford, an astronomer at the University of Florida, Gainesville, who was not involved in the study. "One side is continuously illuminated and scorching hot, while the other side remains in perpetual night."
And conditions will only get worse. Schlaufman says that the same effects that cause tides on Earth also force very hot super-Earths to begin death spirals into their parent stars.
The side of the planet not facing the star will be pulled in one direction, and the side of the planet facing the star will be pulled in another, says Schlaufman. Eventually, before being incinerated, the super-Earth will be ripped apart.

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All About Detergent

As the other cleaning materials, detergents is the fruit of technological advances that make
use of the chemical byproduct of petroleum refining, combined with other chemicals such as phosphate, silicate, dye, and fragrance ingredients.
circa 1960's, early-generation detergent appeared using surface activating chemicals (surfactants) Alkyl Benzene Sulfonate (ABS) which is able to produce foam.




However, due to the difficult nature of the ABS is broken down by microorganisms in the soil surface, eventually replaced with a compound of Linear Alkyl Sulfonate (LAS) are believed to be relatively more familiar with the environment.
In many countries around the world use has been banned and replaced ABS with LAS. While in Indonesia, the rules regarding the prohibition of the use of ABS is still outstanding. Some of the reasons is the use of ABS in detergent products, among others, for their low cost, stability in the form of cream / pasta and abundant foam.
The use of soap as a cleaning agent diluted with water in mountainous areas or swamp the former residential areas often do not produce foam. This is because the nature of soap that will not produce foam when dissolved in hard water (water containing certain metals or lime). However, the use of detergent with water that is hard, will still produce an abundant foam.
Soap or detergent dissolved in water in the washing process, will form the emulsion with dirt that will be wasted when flushing. But there are mistaken opinion that the more abundant foam will make laundry soap water be cleaner. Foam with a large surface area can indeed absorb dirt dust, but the presence of surfactant, the cleaning can be performed without the need for foam.
Deliberately formed opinion that the foam showed abundant labor resources detergent is misleading.So, the washing process does not depend on whether or not the foam or less and the number of foam produced. The ability of these detergent cleaning power can be increased if the laundry is heated because of the power of enzymes and bleach will be effective.However, washing with hot water will cause color to fade clothing. So for colored clothes, you should not use the water warm / hot.
Use of detergents are also often cause new problems, especially for users who have a sensitive nature.Users detergents may experience skin irritation, skin rashes, or skin becomes even more heat after using detergent.

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Tobacco and Diabetes

Agriculture currently produces the rapid development of molecular biotechnology, which can offer a cheaper way than the manufacture of vaccines and traditional medicine through the factory. Scientists have found that healthy tobacco after modifying genetic factors. Tobacco can be used to treat type 1 diabetes.



European researchers say has produced tobacco that contain anti-inflammatory compounds (anti-inflammatory) called interleukin-10 (IL-10) which can help patients with type 1 diabetes who are insulin dependent. A number of agricultural chemical companies, including Bayer and Syngenta, have been looking for ways to make complex proteins in medicinal plants, although requiring a slow process.
At present, most drugs and vaccines produced via cell culture and tissue culture. However, Mario Pezzotti of the University of Verona, who led the study of tobacco published in the journal BMC Biotechnology, believe that the tobacco plants grow more efficiently since the world has a lower cost to produce protein drugs.


Various types of plants have been studied by a number of scientists around the world, but tobacco is the most popular crop in terms of research. Tobacco is a plant that's fantastic because it is easy to transform genetically and can easily learn the whole plant from single cells," said Pezzotti. Group work and put the interests of the tobacco giant, which is Philip Morris, which supports plant-based medicine conference in Verona in June.
Pezzotti and colleagues - who received funding for his research from the European Union - are now planning to megujicobakan these plants to mice that have an autoimmune disease to determine its response.
Next, they wanted to test whether the repetition of small doses can help prevent diabetes in people, when given in conjunction with other compounds of glutamic acid decarboxylase (GAD65), which has also been produced in tobacco plants.

Diamyd, biotechnology companies in Sweden have tested conventional GAD65 vaccine against diabetes during clinical trials. The field of molecular farming has not produced the first commercial product, although Israel Protalix BioTherapeutics has conducted clinical trials on advanced enzymes for the treatment of Gaucher disease generated through a carrot cell culture. Protalix plans to submit the drug for approval from the United States and Israel.


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Telomerase and Aging

Synthesis of the lagging strand requires a short primer which will be removed.  At the extreme end of a chromosome, there is no way to synthesize this region when the last primer is removed.  Therefore, the lagging strand is always shorter than its template by at least the length of the primer.  This is the so-called "end-replication problem".

Bacteria do not have the end-replication problem, because its DNA is circular.   In eukaryotes, the chromosome ends are called telomeres which have at least two functions:

• to protect chromosomes from fusing with each other.
• to solve the end-replication problem.  

The procedure to solve the end-replication problem is outlined in Figure 1.  Mechanism of the telomere extension by telomerase is explained in Figure 2.

 

  Figure 1.  Telomerase and telomere extension.  To extend the length of a telomere, the telomerase first extends its longer strand.  Then, using the same mechanism as synthesizing the lagging strand, the shorter strand is extended.

Figure 2.  The mechanism of telomere extension by telomerase.

 

Aging
In the absence of telomerase, the telomere will become shorter after each cell division.  When it reaches a certain length, the cell may cease to divide and die.  Therefore, telomerase plays a critical role in the aging process.
 

 

 

 

 

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