Monday, May 14, 2007
Asphalt-munching bacteria discovered
Trapped in the Rancho La Brea tar pits 28,000 years ago, the bacteria are equipped with special enzymes that can break down petroleum, environmental scientists at the University of California, Riverside report in a recent issue of Applied and Environmental Microbiology.
“Asphalt is an extreme and hostile environment for life to survive,” said Jong-Shik Kim, who initiated the study. But “these living organisms can survive in heavy oil mixtures containing many highly toxic chemicals” with no water and little oxygen, he said.
Bacteria that survive on petroleum produce methane gas as waste, so when Kim and his colleague Dave Crowley noticed the gas bubbling out of the oily soil, they knew they had found something unique.
The two eventually sequenced groups of the tar pit bacteria’s DNA to be certain. “Previously, some bacteria had been cultured from the asphalt,” Kim said, “but no one had been able to extract DNA from the asphalt to study the entire microbial community.”
To identify the bacteria and their unique enzymes, Kim and Crowley froze the tar with liquid nitrogen and then pulverized it into a powder. With the tar-hungry bacteria exposed, the scientists extracted the DNA.
“Asphalt is an extreme and hostile environment for life to survive,” said Jong-Shik Kim, who initiated the study. But “these living organisms can survive in heavy oil mixtures containing many highly toxic chemicals” with no water and little oxygen, he said.
Bacteria that survive on petroleum produce methane gas as waste, so when Kim and his colleague Dave Crowley noticed the gas bubbling out of the oily soil, they knew they had found something unique.
The two eventually sequenced groups of the tar pit bacteria’s DNA to be certain. “Previously, some bacteria had been cultured from the asphalt,” Kim said, “but no one had been able to extract DNA from the asphalt to study the entire microbial community.”
To identify the bacteria and their unique enzymes, Kim and Crowley froze the tar with liquid nitrogen and then pulverized it into a powder. With the tar-hungry bacteria exposed, the scientists extracted the DNA.
Thursday, May 03, 2007
Mexico finds world's oldest fossil lobster
Mexican scientists said they have identified the world’s oldest lobster fossil, a creature that was alive when Africa was only just breaking apart from the Americas some 120 million years ago.
The fossil is 4.7 inches (12 cm) long and its shell and legs are immaculately preserved by the mud in the southern state of Chiapas where it was found. It is dated as 120 million years old, some 20 million years older than existing lobster fossils.
“This lobster that we found in Chiapas belongs to the genus that is in Africa today,” said geologist Francisco Javier Vega of the National Autonomous University of Mexico, or UNAM.
“This isn’t a surprise because at that time, 120 million years ago, Africa and America were relatively close,” he told Reuters. “It’s very likely that this genus of lobster originated here.”
South America and Africa are believed to have split into two continents around 120 million years ago.
Species sometimes evolved differently on the two continents, explaining why American lobsters today are different from their African cousins.
The juvenile “Palinurus Palaceosi” fossil, dug up in 1995 along with petrified remains of fish, crustaceans and insects, is one of the best preserved lobster fossils in the world and the first found in the Americas, Vega said.
“Practically 90 percent of this specimen’s body has been preserved. It was buried in this microscopic mud (and) has very fine morphological details,” he said.
After a decade of work, Vega and his team established the fossil’s age in 2005 but only published their findings in November 2006 and began publicizing them in the last few weeks.
The fossil is 4.7 inches (12 cm) long and its shell and legs are immaculately preserved by the mud in the southern state of Chiapas where it was found. It is dated as 120 million years old, some 20 million years older than existing lobster fossils.
“This lobster that we found in Chiapas belongs to the genus that is in Africa today,” said geologist Francisco Javier Vega of the National Autonomous University of Mexico, or UNAM.
“This isn’t a surprise because at that time, 120 million years ago, Africa and America were relatively close,” he told Reuters. “It’s very likely that this genus of lobster originated here.”
South America and Africa are believed to have split into two continents around 120 million years ago.
Species sometimes evolved differently on the two continents, explaining why American lobsters today are different from their African cousins.
The juvenile “Palinurus Palaceosi” fossil, dug up in 1995 along with petrified remains of fish, crustaceans and insects, is one of the best preserved lobster fossils in the world and the first found in the Americas, Vega said.
“Practically 90 percent of this specimen’s body has been preserved. It was buried in this microscopic mud (and) has very fine morphological details,” he said.
After a decade of work, Vega and his team established the fossil’s age in 2005 but only published their findings in November 2006 and began publicizing them in the last few weeks.
