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Mysteries ofthe puffer fishrevealed

Puffer fish meat makes an expensive, but potentially deadly, snack. PHOTO: EPA

Scientists in Singapore said they have uncovered the mystery of how the puffer fish survives despite the deadly poison in its body.

Research by the Institute of Molecular and Cell Biology and National University of Singapore showed the toxin, which is 20 times more deadly than cyanide, helps the fish to breed and defend itself against predators.

A process known as "evolutionary adaptation" allows it to become immune to the tetrodotoxin poison which comes from the food it eats, primarily marine life contaminated with the toxin.

"The scientists believe that besides helping to act as a defense against predators, tetrodotoxin resistance has allowed puffer fishes to selectively feed on tetrodotoxin-containing food items which other fish avoid."

It is also the toxin that female puffer fish use to attract their male counterparts during spawning.

The poisonous puffer fish is a highly prized delicacy in Japanese cuisine despite its lethal sting. In Japan, specialist chefs are trained in the art of removing the poison before serving the dish.

Only licensed chefs are allowed to prepare puffer fish for the table in Japan. PHOTO: EPA

Black-and-white bacteria

Biologists say they have created a "living photographic film," made out of engineered intestinal bacteria, that is capable of taking high-resolution black-and-white pictures.

In a study published on Thursday in Nature, the weekly British science weekly, a team led by Christopher Voigt at the University of California at San Francisco started by extracting a light-sensing gene from a germ called a cyanobacterium.

They then stitched the gene into the cell membranes of Escherichia coli bateria, so that exposure to red light switched off a gene called lacZ that controls production of the bug's black pigment.

As a result, black-and-white images can be "stencilled" onto a mat of the engineered bacteria grown on a plate of protein-rich lab gel.

And because the screen's definition is on bacterial scale -- at up to 100 million pixels per square inch (2.5cm2) -- the resolution and tone scale are extraordinarily good.

Newton 1, Einstein 0

Albert Einstein may have made the discoveries that led to nuclear and solar power, lasers and even a physical description of space and time, but Sir Isaac Newton had a greater impact on science and mankind, according to a poll published last week.

Newton, the 17th-century English scientist most famous for describing the laws of gravity and motion, beat Einstein in two polls conducted by eminent London-based scientific academy, the Royal Society.

More than 1,300 members of the public and 345 Royal Society scientists were asked separately which famous scientist made a bigger overall contribution to science, given the state of knowledge during his time, and which made a bigger positive contribution to humankind.

Newton was the winner on all counts, though he beat the German-born Einstein by only 0.2 of a percentage point (50.1 percent to 49.9 percent) in the public poll on who made the bigger contribution to mankind.

The margin was greater among scientists: 60.9 percent for Newton and 39.1 percent for Einstein.

A roadmap for ants

Ants scouting for food place a tiny scent marker on branches that do not lead to a reward, according to a study published by Nature, the weekly British science weekly.

The pheromone acts like a "no-entry signal" to other ants, telling them not to waste their time going down that route, it says.

The discovery was made by animal scientists at Britain's University of Sheffield.

In a lab, they got a scouting colony of Pharaoh ants (Monomorium pharaonis) to explore branches that led to no reward. Paper covers were placed at the branch's forks.

The paper covers were then taken off and transferred to another set of branches. This set had already been explored by another ant colony, which found a tasty meal of sucrose at the end of the trail.

Even though the food reward was still there, ants performed a U-turn or chose another direction whenever they came across the covers.

"It provides advance warning, like human road signs situated before junctions," the authors suggest. -- agencies
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