Category Archives: Life Science

Female Sharks Can Reproduce Alone

Female Sharks Can Reproduce Alone, Researchers Find

A team of American and Irish researchers have discovered that some female sharks can reproduce without having sex, the first time that scientists have found the unusual capacity in such an ancient vertebrate species. The[y] report that sharks can reproduce asexually through the process known as parthenogenesis
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Though the three females had been caught before they reached sexual maturity and held in captivity for more than three years, researchers initially thought one had stored sperm from a male shark before fertilizing an egg. But the team — which included scientists at Nova Southeastern University in Florida, Queen’s University Belfast and the zoo — determined that the baby shark’s genetic makeup perfectly matched one of the females in the tank, with no sign of a male parent.

Mahmood Shivji — Nova Southeastern’s Guy Harvey Research Institute director and one of the paper’s authors — said that he and his colleagues determined that a byproduct formed when sharks produce eggs, known as a sister polar body, had fused with an unfertilized egg to produce the baby shark, whose DNA had only half as much genetic variability as the mother.

Water Buffaloes, Lions and Crocodiles Oh My

Pretty amazing video. A look at real wild life with lots of excitement, a bit violence and some surprising turns. On my trip to Kenya I saw an interaction between lions and one water buffalo but it was without much of this action. Basically there was a standoff for like half an hour with half charges and the like. Even that was very interesting.

Deep-Sea Alien Abode Discovered

Deep-Sea Alien Abode Discovered by Jeanna Bryner:

Recent expeditions have uncloaked this polar region, finding nearly 600 organisms never described before and challenging some assumptions that deep-sea biodiversity is depressed. The findings also suggest that all of Earth’s marine life originated in Antarctic waters.

Scientists had assumed that the deep sea of the South Pole would follow similar trends in biodiversity documented for the Arctic. “There are less species in the Arctic than around the equator,” said one of the study scientists, Brigitte Ebbe, a taxonomist at the German Center for Marine Biodiversity Research. “People assumed that it would be the same if you went from the equator south, but it didn’t prove to be true at all.”

Very interesting stuff. Related: Altered Oceans, the Crisis at Sea – Ocean Life – Antarctic Robo-sub

Bird Species Plummeted After West Nile

Bird Species Plummeted After West Nile:

Several common species of North American birds have suffered drastic population declines since the arrival of the West Nile virus eight years ago, leaving rural and suburban areas quieter than they used to be and imposing ecological stresses on a variety of other animals and plants, a new study has found.

In Maryland, for example, 2005 chickadee populations were 68 percent lower than would have been expected had West Nile not arrived, and in Virginia chickadee populations were 50 percent below that prediction.
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It shows that the post-1998 declines were greatest at times and places in which the virus was especially prevalent — as indicated by the number of human infections diagnosed. As expected, American crows were among the worst hit, suffering declines of as much as 45 percent in some regions and wipeouts of 100 percent in some smaller areas. Other species that suffered included the blue jay, the tufted titmouse, the American robin, the house wren, the chickadee and — unexpectedly — the American bluebird.

Bacterium Living with High Level Radiation

Organism found at SRS amazes scientific world by Rob Pavey

In addition to thriving in the face of normally-lethal radiation, the organism also demonstrates remarkable survival characteristics in terms of its DNA. Humans and most organisms can tolerate few breaks in DNA molecules, he said, but kineococcus radiotolerans has the ability to reassemble itself.

“With this organism, we can take an intact DNA molecule, blast it into little pieces, and in five to six hours the organism is restored and growing normally again,” Dr. Bagwell said. Dr. Bagwell and others who have studied the organism hope further research will yield clues that could aid in medical research, cancer studies and other areas.

“There’s a lot of excitement about this organism because of its ability to withstand tremendous abuse,” he said. “What we don’t know is how it does these things – and what more it can do. That’s the direction we’re going now.”

Related: What is an Extremophile? – more info on Kineococcus radiotolerans

Microorganisms on Spaceships

Space Mold photo

Preventing “Sick” Spaceships, NASA:

Moreover, the mass of water was only one of several hiding behind different panels. Scientists later concluded that the water had condensed from humidity that accumulated over time as water droplets coalesced in microgravity. The pattern of air currents in Mir carried air moisture preferentially behind the panel, where it could not readily escape or evaporate.

Nor was the water clean: two samples were brownish and a third was cloudy white. Behind the panels the temperature was toasty warm—82ÂºF (28ÂºC)—just right for growing all kinds of microbeasties. Indeed, samples extracted from the globules by syringes and returned to Earth for analysis contained several dozen species of bacteria and fungi, plus some protozoa, dust mites, and possibly spirochetes.

But wait, there’s more. Aboard Mir, colonies of organisms were also found growing on “the rubber gaskets around windows, on the components of space suits, cable insulations and tubing, on the insulation of copper wires, and on communications devices,”

Photo: Dust mite was found floating in a globule of water onboard Mir. Other microorganisms collected include protozoa and amoeba. [Read more – Microbial Characterization of Free Floating Condensate
aboard the Mir Space Station – pdf]

Diversity Efforts for the Life Science Work Force

Focus on Diversity: INCUBATING INNOVATION – Diversity Efforts Rejuvenate the Life Science Work Force by Alethea Hannemann:

Support for undergraduate and graduate programs that encourage African-American scientists also comes from industry leaders. Merck, in a partnership with the United Negro College Fund, awards at least 37 scholarships a year to African-American researchers at the undergraduate, graduate, and postdoctoral levels; to date, the program has trained more than 370 scientists.
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In the end, building a robust, diverse science work force will take vigorous effort from many camps. The good news is that a host of programs in government, academia, and industry are dedicated to increasing the numbers of African-Americans in science. With continued efforts, education and recruiting programs should soon bear fruit, bringing new power to the life sciences.

Opossum Genome Shows ‘Junk’ DNA is Not Junk

Opossum Genome Shows ‘Junk’ DNA Source Of Genetic Innovation

Scientists previously thought that evolution slowly changed the genes that create specific proteins. As the proteins changed, so did the creatures that owned them. The current research shows that opossum and human protein-coding genes have changed little since their ancestors parted ways, 180 million years ago. It has been the regulation of their genes – when they turn on and off – that has changed dramatically.

“Evolution is tinkering much more with the controls than it is with the genes themselves,” said Broad Institute director Eric Lander. “Almost all of the new innovation … is in the regulatory controls. In fact, marsupial mammals and placental mammals have largely the same set of protein-coding genes. But by contrast, 20 percent of the regulatory instructions in the human genome were invented after we parted ways with the marsupial.”
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It had been initially thought that most of a creature’s DNA was made up of protein-coding genes and that a relatively small part of the DNA was made up of regulatory portions that tell the rest when to turn on and off. As studies of mammalian genomes advanced, however, it became apparent that that view was incorrect. The regulatory part of the genome was two to three times larger than the portion that actually held the instructions for individual proteins.

Very interesting. The more recent articles I read on DNA discoveries the more interesting it seems to get. Related: Learning About the Human Genome – New Understanding of Human DNA – DNA Transcription Webcast

Encyclopedia of Life

Our goal is to create a constantly evolving encyclopedia that lives on the Internet, with contributions from scientists and amateurs alike. To transform the science of biology, and inspire a new generation of scientists, by aggregating all known data about every living species. And ultimately, to increase our collective understanding of life on Earth, and safeguard the richest possible spectrum of biodiversity.

They are using wiki technology to create an encyclopedia of life as discussed by E.O. Wilson in his TED Prize Wish speech. It seems like a great idea to me.

South Pacific to Stop Bottom-trawling

S Pacific to stop bottom-trawling:

A quarter of the world’s oceans will be protected from fishing boats which drag heavy nets across the sea floor, South Pacific nations have agreed. The landmark deal will restrict bottom-trawling, which experts say destroys coral reefs and stirs up clouds of sediment that suffocate marine life. Observers and monitoring systems will ensure vessels remain five nautical miles from marine ecosystems at risk.

From my previous post, Fishy Future?:

The measured effects today should be enough for sensible people to realise the tragedy of the commons applies to fishing and obviously governments need to regulate the fishing to assure that fishing is sustainable. This is a serious problem exacerbated by scientific and economic illiteracy. The obvious scientific and economic solution is regulation. Determining the best regulation is tricky (and political and scientific and economic) but obviously regulation (and enforcement) is the answer.

Granted I have a very limited knowledge of this area, but this ban seems like a good idea to me.