Tag Archives: microbes

Bacteria Frozen for 8 Million Years In Polar Ice Resuscitated

Eight-million-year-old bug is alive and growing

Kay Bidle of Rutgers University in New Jersey, US, and his colleagues extracted DNA and bacteria from ice found between 3 and 5 metres beneath the surface of a glacier in the Beacon and Mullins valleys of Antarctica. The ice gets older as it flows down the valleys and the researchers took five samples that were between 100,000 and 8 million years old.

They then attempted to resuscitate the organisms in the oldest and the youngest samples. “We tried to grow them in media, and the young stuff grew really fast. We could plate them and isolate colonies,” says Bidle. The cultures grown from organisms found in the 100,000-year-old ice doubled in size every 7 days on average.

Whereas the young ice contained a variety of microorganisms, the researchers found only one type of bacterium in the 8-million-year-old sample. It also grew in the laboratory but much more slowly, doubling only every 70 days.

Related: What is an Extremophile?

Bdelloid Rotifers Abandoned Sex 100 Million Years Ago

Who Needs Sex (or Males) Anyway? by Liza Gross:

If you own a birdbath, chances are you’re hosting one of evolutionary biology’s most puzzling enigmas: bdelloid rotifers. These microscopic invertebrates—widely distributed in mosses, creeks, ponds, and other freshwater repositories—abandoned sex perhaps 100 million years ago, yet have apparently diverged into nearly 400 species. Bdelloids (the “b” is silent) reproduce through parthenogenesis, which generates offspring with essentially the same genome as their mother from unfertilized eggs.

Scientists stumped by 100m years of chastity

Bdelloid rotifers are egg laying microscopic invertebrates — widely distributed in mosses, streams and ponds — which have managed to diverge into nearly 400 species without a scintilla of sex… Now a new study, published today in the journal PLoS biology, has confirmed the worst fears of scientists: the rotifers do indeed present a major challenge to the assumption that sex is necessary for organisms to diversify into species.
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Rather than mixing up DNA, creatures like the bdelloid rotifers can evolve solely through the build-up of mutations that occur in the ‘cloning’ process when a new rotifer is born. The new study proves that these differences are not random and can help rotifers adapt to a different environment, such as the legs or chest of a water louse. Bdelloids can be found happily swimming around in a puddle in your garden, hot springs or in freezing ponds in the Antarctic.

What is an Extremophile?

An extremophile is an organism that thrives under “extreme” conditions. The term frequently refers to prokaryotes and is sometimes used interchangeably with Archaea.
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The term extremophile is relatively anthropocentric. We judge habitats based on what would be considered “extreme” for human existence. Many organisms, for example, consider oxygen to be poisonous.

The site includes interesting photos and details on all sorts of extremophiles: Anaerobe (don’t require oxygen) – Endolith (live inside rocks) – Thermophile (enjoy over 40 Â°C).

Microbes

photo of T4 bacteriophage

Photo: T4 bacteriophage, middle, is a virus that invades bacterial cells. Courtesy of the MicrobeLibrary.org

The MicrobeWorld web site includes an introduction to microbes – Microbes: what they are and what they do:

Microbes are single-cell organisms so tiny that millions can fit into the eye of a needle.

They are the oldest form of life on earth. Microbe fossils date back more than 3.5 billion years to a time when the Earth was covered with oceans that regularly reached the boiling point, hundreds of millions of years before dinosaurs roamed the earth.

Microbes types:

Archaea
These bacteria look-alikes are living fossils that are providing clues to the earliest forms of life on Earth.

Bacteria
Often dismissed as “germs” that cause illness, bacteria help us do an amazing array of useful things, like make vitamins, break down some types of garbage, and maintain our atmosphere.

Fungi
From a single-celled yeast to a 3.5-mile-wide mushroom, fungi do everything from helping to bake bread to recycling to decomposing waste.

Protista
Plant-like algae produce much of the oxygen we breathe; animal-like protozoa (including the famous amoeba) help maintain the balance of microbial life.

Viruses
Unable to do much of anything on their own, viruses go into host cells to reproduce, often wreaking havoc and causing disease. Their ability to move genetic information from one cell to another makes them useful for cloning DNA and could provide a way to deliver gene therapy.