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NASA’s Mars Curiosity Rover

Posted on June 16, 2011  Comments (6)

Curiosity is the name of the new rover from NASA. It will be launched to continue the exploration of Mars so successfully done by Spirit and Opportunity (2 previous Mars rovers that did some amazing work and laster years longer than expected). The rover is NASA’s Mars Science Laboratory, a mobile robot for investigating Mars’ past or present ability to sustain microbial life.

photo of NASA's Mars Rover: Curiosity

Once on the surface, the rover will be able to roll over obstacles up to 75 centimeters (29 inches) high and travel up to 90 meters per hour. On average, the rover is expected to travel about 30 meters per hour, based on power levels, slippage, steepness of the terrain, visibility, and other variables.

The rover is about the size of a small SUV — 10 feet long (not including the arm), 9 feet wide and 7 feet tall. It weighs 900 kilograms (2,000 pounds)

The rover will carry a radioisotope power system that generates electricity from the heat of plutonium’s radioactive decay. This power source gives the mission an operating lifespan on Mars’ surface of a full martian year (687 Earth days) or more, while also providing significantly greater mobility and operational flexibility, enhanced science payload capability, and exploration of a much larger range of latitudes and altitudes than was possible on previous missions to Mars.

Related: Mars Rover Continues Exploration – Mars Rovers Getting Ready for Another Adventure (2007) – Sunset on Mars

Changing Life as We Know It

Posted on December 2, 2010  Comments (1)

Update: Independent researchers find no evidence for arsenic life in Mono Lake

NASA has made a discovery that changes our understanding of the very makeup of life itself on earth. I think my favorite scientific discipline name is astrobiology. NASA pursues a great deal of this research not just out in space but also looking at earth based life. Their astrobiology research has changed the fundamental knowledge about what comprises all known life on Earth.

photo of Felisa Wolfe-Simon

Felisa Wolfe-Simon processing mud from Mono Lake to inoculate media to grow microbes on arsenic.

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.

Researchers conducting tests in the harsh, but beautiful (see photo), environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.

“The definition of life has just expanded,” said Ed Weiler, NASA’s associate administrator for the Science Mission Directorate. “As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it.” This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth.

In science such huge breakthroughs are not just excepted without debate, however, which is wise.

Thriving on Arsenic:

In other words, every experiment Wolfe-Simon performed pointed to the same conclusion: GFAJ-1 can substitute arsenic for phosphorus in its DNA. “I really have no idea what another explanation would be,” Wolfe-Simon says.

But Steven Benner, a distinguished fellow at the Foundation for Applied Molecular Evolution in Gainesville, FL, remains skeptical. If you “replace all the phosphates by arsenates,” in the backbone of DNA, he says, “every bond in that chain is going to hydrolyze [react with water and fall apart] with a half-life on the order of minutes, say 10 minutes.” So “if there is an arsenate equivalent of DNA in that bug, it has to be seriously stabilized” by some as-yet-unknown mechanism.

It is sure a great story if it is true though. Other scientists will examine more data and confirm or disprove the claims.

“We know that some microbes can breathe arsenic, but what we’ve found is a microbe doing something new — building parts of itself out of arsenic,” said Felisa Wolfe-Simon, a NASA Astrobiology Research Fellow in residence at the U.S. Geological Survey in Menlo Park, Calif., and the research team’s lead scientist. “If something here on Earth can do something so unexpected, what else can life do that we haven’t seen yet?”
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A single Liter of Seawater Can Hold More Than One Billion Microorganisms

Posted on April 20, 2010  Comments (0)

Mat of microbes the size of Greece discovered on seafloor

mighty microbes, which constitute 50 to 90 percent of the oceans’ total biomass, according to newly released data.

These tiny creatures can join together to create some of the largest masses of life on the planet, and researchers working on the decade-long Census of Marine Life project found one such seafloor mat off the Pacific coast of South America that is roughly the size of Greece.

A single liter of seawater, once thought to contain about 100,000 microbes, can actually hold more than one billion microorganisms, the census scientists reported. But these small creatures don’t just live in the water column or on the seafloor. Large communities of microscopic animals have even been discovered more than one thousand meters beneath the seafloor. Some of these deep burrowers, such as loriciferans, are only a quarter of a millimeter long.

“Far from being a lifeless desert, the deep sea rivals such highly diverse ecosystems as tropical rainforests and coral reefs,”
…
Microbes help to turn atmospheric carbon dioxide into usable carbon, completing about 95 percent of all respiration in the Earth’s oceans…

Related: Iron-breathing Species Isolated in Antarctic for Millions of Years – Life Far Beneath the Ocean – Life Untouched by the Sun

Invisible Worlds: Fastest Thing on the Planet

Posted on March 18, 2010  Comments (1)

Fun with Fungi.

Related: Secret Life of Microbes – Plants, Unikonts, Excavates and SARs – Smallest Known Living Organisms Found – 200 nanometers

Researchers Explain How Rotifers Thrive Despite Forgoing Sex

Posted on February 21, 2010  Comments (1)

Bdelloid rotifers haven’t had sex for at least thirty million years. Most asexual animals are doomed to extinction. The excellent show, Science Friday, looks at the extraordinary adaptations that allow rotifers to thrive sex-free.

For millions of years, the rotifers have reproduced asexually, flying in the face of an idea known as the Red Queen Hypothesis, which states that without the advantage of sexual reproduction, more-rapidly evolving parasites and predators will eventually doom the asexual species. Now, the researchers studying the tiny organism say that its ability to dry up and blow away to greener pastures may have given the rotifers a hidden tactical edge in this evolutionary war.

The webcast provides a nice overview of the research. Every week Science Friday provides many such interesting reviews of recent scientific research.

What Are Rotifers?

Rotifers are small, mostly freshwater animals, and are amongst the smallest members of the Metazoa — that group of multicellular animals which includes humans, and whose bodies are organized into systems of organs.
Most rotifers are about 0.5mm in length or less, and their bodies have a total of around a thousand cells. This means that their organ systems are a greatly simplified distillation of the organ systems found in the bodies of the higher animals.

A typical rotifer might have a brain of perhaps fifteen cells with associated nerves and ganglia, a stomach of much the same number, an excretory system of only a dozen or so cells, and a similarly fundamental reproductive system. They have no circulatory system. It is an anomaly that despite their complexity, many rotifers are much smaller than common single-celled organisms whose world they share.
…
they are able to survive long periods — even perhaps hundreds of years — in a dried or frozen state, and will resume normal behaviour when rehydrated or thawed.
Secondly, they exhibit what biologists call cell constancy — they grow in size not by cell division, but by increase in the size of the cells which they already have.

Related: Bdelloid Rotifers Abandoned Sex 100 Million Years Ago – Fungus-gardening Ant Species Has Given Up Sex Completely – Amazon Molly Fish are All Female – 50 Species of Diatoms

Microbes Flourish In Healthy People

Posted on January 15, 2010  Comments (1)

Bugs Inside: What Happens When the Microbes That Keep Us Healthy Disappear? by Katherine Harmon

The human body has some 10 trillion human cells—but 10 times that number of microbial cells. So what happens when such an important part of our bodies goes missing?
…
“Someone who didn’t have their microbes, they’d be naked,” says Martin Blaser, a professor of microbiology and chair of the Department of Medicine at New York University Langone Medical Center in New York City.
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Even though it is such an apparently integral and ancient aspect of human health, scientists are still grasping for better ways to study human microbiota—before it changes beyond historical recognition. Borrowing models from outside of medicine has helped many in the field gain a better understanding of this living world within us. “The important concept is about extinctions,” Blaser says. “It’s ecology.”
…
The first step in understanding these systems is simply taking stock of what archaea, bacteria, fungi, protozoa and viruses are present in healthy individuals. This massive micro undertaking has been ongoing since 2007 through the National Institutes of Health’s (NIH) Human Microbiome Project. So far it has turned up some surprisingly rich data, including genetic sequencing for some 205 of the different genera that live on healthy human skin.

Despite the flood of new data, Foxman laughs when asked if there is any hope for a final report from the Human Microbiome Project any time soon. “This is the very, very beginning,” she says, comparing this project with the NIH’s Human Genome Project, which jump-started a barrage of new genetic research. “There are basic, basic questions that we don’t know the answers to,” she says, such as how different microbiota are between random individuals or family members; how much microbiota change over time; or how related the microbiota are to each other on or inside a person’s body.

Related: Microcosm by Carl Zimmer – Tracking the Ecosystem Within Us – Alligator Blood Provides Strong Resistance to Bacteria and Viruses – Beneficial Bacteria

Microcosm by Carl Zimmer

Posted on December 26, 2009  Comments (0)

cover of Microcosm by Carl Zimmer

Microcosm: E. Coli and the New Science of Life by Carl Zimmer is an excellent book. It is full of fascinating information and as usual Carl Zimmer’s writing is engaging and makes complex topics clear.

E-coli keep the level of oxygen low in the gut making the resident microbes comfortable. At any time a person will have as many as 30 strains of E. coli in their gut and it is very rare for someone ever to be free of E. coli. [page 53]

In 1943, Luria and Delbruck published the results that won them the 1969 Nobel Prize in Physiology or Medicine in which they showed that bacteria and viruses pass down their traits using genes (though it took quite some time for the scientific community at large to accept this). [page 70]

during a crisis E coli’s mutation rates could soar a hundred – or even a thousandfold… Normally, natural selection favors low mutation rates, since most mutations are harmful. But in times of stress extra mutations may raise the odds that organisms will hit on a way out of their crisis… [alternatively, perhaps] In times of stress, E coli. may not be able to afford the luxury of accurate DNA repair. Instead, it turns to the cheaper lo-fi polymerases. While they may do a sloppier job, E coli. comes out ahead [page 106]
Hybridization is not the only way foreign DNA got into our cells. Some 3 billion years ago our single-celled ancestors engulfed oxygen-breathing bacteria, which became the mitochondria on which we depend. And, like E. coli, our genomes have taken in virus upon virus. Scientists have identified more than 98,000 viruses in the human genome, along with our mutant vestiges of 150,00 others… If we were to strip out all our transgenic DNA, we would become extinct.

I highly recommend Microcosm, just as I highly recommend Parasite Rex, by Carl Zimmer.

Related: Bacteriophages: The Most Common Life-Like Form on Earth – Foreign Cells Outnumber Human Cells in Our Bodies – Amazing Designs of Life – Amazing Science: Retroviruses – One Species’ Genome Discovered Inside Another’s

Dennis Bray Podcast on Microbes As Computers

Posted on October 13, 2009  Comments (1)

Carl Zimmer interviews Dennis Bray in an interesting podcast:

Dennis Bray is an active professor emeritus in both the Department of Physiology and Department of Neuroscience at the University of Cambridge. He studies the behavior of microbes–how they “decide” where to swim, when to divide, and how best to manage the millions of chemical reactions taking place inside their membranes. For Bray, microbes are tiny, living computers, with genes and proteins serving the roles of microprocessors.

Related: E. Coli Individuality – Wetware: A Computer in Every Living Cell by Dennis Bray – Programing Bacteria – Micro-robots to ‘swim’ Through Veins

Iron-breathing Species Isolated in Antarctic for Millions of Years

Posted on April 25, 2009  Comments (2)

Graphic showing environment of Antarctic subglacial microbesGraphic of Blood Falls showing microbial community environment in the Antarctic by Zina Deretsky at NSF)

A reservoir of briny liquid buried deep beneath an Antarctic glacier supports hardy microbes that have lived in isolation for millions of years, researchers report this week. The discovery of life in a place where cold, darkness, and lack of oxygen would previously have led scientists to believe nothing could survive comes from a team led by researchers at Harvard University and Dartmouth College.

Despite their profound isolation, the microbes are remarkably similar to species found in modern marine environments, suggesting that the organisms now under the glacier are the remnants of a larger population that once occupied an open fjord or sea.

“It’s a bit like finding a forest that nobody has seen for 1.5 million years,” says Ann Pearson, Thomas D. Cabot Associate Professor of Earth and Planetary Sciences in Harvard’s Faculty of Arts and Sciences. “Intriguingly, the species living there are similar to contemporary organisms, and yet quite different — a result, no doubt, of having lived in such an inhospitable environment for so long.”

“This briny pond is a unique sort of time capsule from a period in Earth’s history,” says lead author Jill Mikucki, now a research associate in the Department of Earth Sciences at Dartmouth and visiting fellow at Dartmouth’s Dickey Center for International Understanding and its Institute of Arctic Studies. “I don’t know of any other environment quite like this on Earth.”

Chemical analysis of effluent from the inaccessible subglacial pool suggests that its inhabitants have eked out a living by breathing iron leached from bedrock with the help of a sulfur catalyst. Lacking any light to support photosynthesis, the microbes have presumably survived by feeding on the organic matter trapped with them when the massive Taylor Glacier sealed off their habitat an estimated 1.5 to 2 million years ago.
Continue reading →

Tardigrades

Posted on January 27, 2009  Comments (5)

Tardigrades (commonly known as water bears) have eight legs and are their own phylum on the tree of life. Some can survive temperatures close to absolute zero, temperatures as high as 151 °C (303 °F), 1,000 times more radiation than any other animal, nearly a decade without water, and even the vacuum of space.

Related: Tardigrades, UNC Chapel Hill – Tardigrades In Space (TARDIS) – What is an Extremophile? – Evolution, Methane, Jobs, Food and More

Evolution, Methane, Jobs, Food and More

Posted on January 17, 2009  Comments (2)

photo of sunset on Mars
Photo from May 2005 by NASA’s Mars Exploration Rover Spirit as the Sun sank below the rim of Gusev crater on Mars.

Science Friday is a great National Public Radio show. The week was a great show covering Antimicrobial Copper, Top Jobs for Math and Science, Human-Driven Evolution, Methane On Mars, Fish with Mercury and more. This show, in particular did a great job of showing the scientific inquiry process in action.

“Fishing regulations often prescribe the taking of larger fish, and the same often applies to hunting regulations,” said Chris Darimont, one of the authors of the study. “Hunters are instructed not to take smaller animals or those with smaller horns. This is counter to patterns of natural predation, and now we’re seeing the consequences of this management.” Darimont and colleagues found that human predation accelerated the rate of observable trait changes in a species by 300 percent above the pace observed within purely natural systems, and 50 percent above that of systems subject to other human influences, such as pollution

Very interesting stuff, listen for more details. A part of what happens is those individuals that chose to focus on reproducing early (instead of investing in growing larger, to reproduce later) are those that are favored (they gain advantage) by the conditions of human activity. I am amazed how quickly the scientists says the changes in populations are taking place.

And Methane On Mars is another potentially amazing discovery. While it is far from providing proof of live on Mars it is possibly evidence of life on Mars. Which would then be looked back on as one of the most important scientific discoveries ever. And in any even the podcast is a great overview of scientists in action.

This week astronomers reported finding an unexpected gas — methane — in the Martian atmosphere. On Earth, a major source of methane is biological activity. However, planetary scientists aren’t ready to say that life on Mars is to blame for the presence of the gas there, as geochemical processes could also account for the finding. The find is intriguing especially because the researchers say they have detected seasonal variations of methane emissions over specific locations on the planet.

Martian Methane Reveals the Red Planet is not a Dead Planet
The Mars Methane Mystery: Aliens At Last?

Related: Mars Rover Continues Exploration – Copper Doorknobs and Faucets Kill 95% of Superbugs – Viruses and What is Life – posts on evolution – Science and Engineering Link Directory

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