Tag Archives: microbes

Life After the Chernobyl Nuclear Accident

Silent Spring by Lauren Monaghan, Cosmos

Ever since, a 30 km ‘exclusion zone’ has existed around the contaminated site, accessible to those with special clearance only. It’s quite easy, then, to conjure an apocalyptic vision of the area; to imagine an eerily deserted wasteland, utterly devoid of life.

But the truth is quite the opposite. The exclusion zone is teeming with wildlife of all shapes and sizes, flourishing unhindered by human interference and seemingly unfazed by the ever-present radiation. Most remarkable, however, is not the life buzzing around the site, but what’s blooming inside the perilous depths of the reactor.

Sitting at the centre of the exclusion zone, the damaged reactor unit is encased in a steel and cement sarcophagus. It’s a deathly tomb that plays host to about 200 tonnes of melted radioactive fuel, and is swarming with radioactive dust.

But it’s also the abode of some very hardy fungi which researchers believe aren’t just tolerating the severe radiation, but actually harnessing its energy to thrive.

“Our findings suggest that [the fungi] can capture the energy from radiation and transform it into other forms of energy that can be used for growth,” said microbiologist Arturo Casadevall from the Albert Einstein College of Medicine at Yeshiva University in New York, USA.
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Taken together, the researchers think their results do indeed hint that fungi can live off ionising radiation, harnessing its energy through melanin to somehow generate a new form of biologically usable growing power.

If they’re right, then this is powerful stuff, said fungal biologist Dee Carter from the University of Sydney. The results will challenge fundamental assumptions we have about the very nature of fungi, she said.

It also raises the possibility that fungi might be using melanin to secretly harvest visible and ultraviolet light for growth, adds Casadevall. If confirmed, this will further complicate our understanding of these sneaky organisms and their role in ecosystems.

Pretty amazing stuff. It really is great all that nature gives us to study and learn about using science.

Microbes Beneath the Sea Floor

This stuff is cool. Here is the full press release from Penn State, Microbes beneath sea floor genetically distinct

Tiny microbes beneath the sea floor, distinct from life on the Earth’s surface, may account for one-tenth of the Earth’s living biomass, according to an interdisciplinary team of researchers, but many of these minute creatures are living on a geologic timescale.

“Our first study, back in 2006, made some estimates that the cells could double every 100 to 2,000 years,” says Jennifer F. Biddle, PhD. recipient in biochemistry and former postdoctoral fellow in geosciences, Penn State. Biddle is now a postdoctoral associate at the University of North Carolina, Chapel Hill.

The researchers looked at sediment samples from a variety of depths taken off the coast of Peru at Ocean Drilling Site 1229. They report their findings in today’s (July 22) online issue of the Proceedings of the National Academy of Sciences.

“The Peruvian Margin is one of the most active surface waters in the world and lots of organic matter is continuously being deposited there,” says Christopher H. House, associate professor of geoscience. “We are interested in how the microbial world differs in the subsea floor from that in the surface waters.”

The researchers used a metagenomic approach to determine the types of microbes residing in the sediment 3 feet, 53 feet, 105 feet and 164 feet beneath the ocean floor. The use of the metagenomics, where bulk samples of sediment are sequences without separation, allows recognition of unknown organism and determination of the composition of the ecosystem.

“The results show that this subsurface environment is the most unique environment yet studied metagenomic approach known today,” says House. “The world does look very different below the sediment surface.” He notes that a small number of buried genetic fragments exist from the water above, but that a large portion of the microbes found are distinct and adapted to their dark and quiet world.

The researchers, who included Biddle; House; Stephan C. Schuster, associate professor; and Jean E. Brenchley, professor, biochemistry and molecular biology, Penn State; and Sorel Fitz-Gibbon, assistant research molecular biologist at the Center for Astrobiology, UCLA, found that a large percentage of the microbes were Archaea, single-celled organisms that look like Bacteria but are different on the metabolic and genetic levels. The percentage of Archaea increases with depth so that at 164 feet below the sea floor, perhaps 90 percent of the microbes are Archaea. The total number of organisms decreases with depth, but there are lots of cells, perhaps as many as 1,600 million cells in each cubic inch.
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Too Toxic for Microorganisms – Not

The Pit of Life and Death by Richard Solensky:

The water became as acidic as lemon juice, creating a toxic brew of heavy metal poisons including arsenic, lead, and zinc. No fish live there, and no plants line the shores. There aren’t even any insects buzzing about. The Berkeley Pit had become one of the deadliest places on earth, too toxic even for microorganisms. Or so it was thought.
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the researchers identified it as Euglena mutabilis, a protozoan which has the remarkable ability of being able to survive in the toxic waters of the Berkeley Pit by altering its local environment to something more hospitable. Through photosynthesis, it increases the oxygen level in the water, which causes dissolved metals to oxidize and precipitate out. In addition, it pulls iron out of the water and sequesters it inside of itself. This makes it a classic example of an extremophile.

Bacteria Evolutionary Shift Seen in the Lab

Bacteria make major evolutionary shift in the lab

A major evolutionary innovation has unfurled right in front of researchers’ eyes. It’s the first time evolution has been caught in the act of making such a rare and complex new trait. And because the species in question is a bacterium, scientists have been able to replay history to show how this evolutionary novelty grew from the accumulation of unpredictable, chance events.
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sometime around the 31,500th generation, something dramatic happened in just one of the populations – the bacteria suddenly acquired the ability to metabolise citrate, a second nutrient in their culture medium that E. coli normally cannot use. Indeed, the inability to use citrate is one of the traits by which bacteriologists distinguish E. coli from other species.
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The replays showed that even when he looked at trillions of cells, only the original population re-evolved Cit+ – and only when he started the replay from generation 20,000 or greater. Something, he concluded, must have happened around generation 20,000 that laid the groundwork for Cit+ to later evolve.

Lenski and his colleagues are now working to identify just what that earlier change was, and how it made the Cit+ mutation possible more than 10,000 generations later.

Bacteria “Feed” on Earth’s Ocean-Bottom Crust

Once considered a barren plain dotted with hydrothermal vents, the seafloor’s rocky regions appear to be teeming with microbial life, say scientists
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“Initial research predicted that life could in fact exist in such a cold, dark, rocky environment,” said Santelli. “But we really didn’t expect to find it thriving at the levels we observed.” Surprised by this diversity, the scientists tested more than one site and arrived at consistent results, making it likely, according to Santelli and Edwards, that rich microbial life extends across the ocean floor. “This may represent the largest surface area on Earth for microbes to colonize,” said Edwards.
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Santelli and Edwards also found that the higher microbial diversity on ocean-bottom rocks compared favorably with other life-rich places in the oceans, such as hydrothermal vents. These findings raise the question of where these bacteria find their energy, Santelli said.

“We scratched our heads about what was supporting this high level of growth,” Edwards said. With evidence that the oceanic crust supports more bacteria than overlying water, the scientists hypothesized that reactions with the rocks themselves might offer fuel for life.

Why doesn’t this stuff make the news over what some celebrity did or politician said… (well I must admit I am just guessing since I don’t actually watch the news or read the mass media much – other than some science, investing or economics content). Oh well, at least you get to read the Curious Cat Science blog and find out about some of the cool stuff being learned every day.

High School Student Isolates Microbe that Eats Plastic

WCI student isolates microbe that lunches on plastic bags

Daniel Burd’s project won the top prize at the Canada-Wide Science Fair in Ottawa. He came back with a long list of awards, including a $10,000 prize, a $20,000 scholarship, and recognition that he has found a practical way to help the environment.
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First, he ground plastic bags into a powder. Next, he used ordinary household chemicals, yeast and tap water to create a solution that would encourage microbe growth. To that, he added the plastic powder and dirt. Then the solution sat in a shaker at 30 degrees.

After three months of upping the concentration of plastic-eating microbes, Burd filtered out the remaining plastic powder and put his bacterial culture into three flasks with strips of plastic cut from grocery bags. As a control, he also added plastic to flasks containing boiled and therefore dead bacterial culture.

Six weeks later, he weighed the strips of plastic. The control strips were the same. But the ones that had been in the live bacterial culture weighed an average of 17 per cent less.
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The inputs are cheap, maintaining the required temperature takes little energy because microbes produce heat as they work, and the only outputs are water and tiny levels of carbon dioxide — each microbe produces only 0.01 per cent of its own infinitesimal weight in carbon dioxide, said Burd.

“This is a huge, huge step forward . . . We’re using nature to solve a man-made problem.” Burd would like to take his project further and see it be used. He plans to study science at university, but in the meantime he’s busy with things such as student council, sports and music.

Bacteriophages: The Most Common Life-Like Form on Earth

There are more bacteriophages on Earth than any other life-like form. These small viruses are not clearly a form of life, since when not attached to bacteria they are completely dormant. Bacteriophages attack and eat bacteria and have likely been doing so for over 3 billion years. Although initially discovered early last century, the tremendous abundance of phages was realized more recently when it was found that a single drop of common seawater typically contains millions of them. Extrapolating, phages are likely to be at least a billion billion times more numerous than humans. Pictured above is an electron micrograph of over a dozen bacteriophages attached to a single bacterium. Phages are very small — it would take about a million of them laid end-to-end to span even one millimeter. The ability to kill bacteria makes phages a potential ally against bacteria that cause human disease, although bacteriophages are not yet well enough understood to be in wide spread medical use.

Photo credit: Wikipedia Electron micrograph of bacteriophages attached to a bacterial cell. These viruses have the size and shape of coliphage T1.; Insert: Mike Jones

Viruses Eating Bacteria

All the World’s a Phage by John Travis:

“Believe it or not, nobody had looked before,” says Suttle. “On average, there are 50 million viruses per milliliter in seawater. The question is, What the heck they’re doing there?” Microbiologists then documented similar, and even higher, concentrations of phages in soil samples. This led to estimates of 10³¹ bacteriophages worldwide, a staggeringly large number that many scientists initially dismissed. “We can’t wrap our brains around it,” says Pedulla. “If phages were the size of a beetle, they would cover the Earth and be many miles deep.”
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According to estimates put forth by Suttle, phages destroy up to 40 percent of the bacteria in Earth’s oceans each day.
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The students collected soil from barnyards, gardens, and even the monkey pit at the Bronx Zoo. The scientists then taught the students how to isolate a bacteriophage from the soil by growing the viruses in Mycobacterium smegmatis, a harmless bacterial relative of the microbe that causes tuberculosis. “We guarantee them that the bacteriophage they find will never have been discovered before. We know that because the diversity is so high, and we’ve never isolated the same bacteriophage twice,” says Hatfull.

In the April 18 Cell, Hatfull and his professional and teenage collaborators describe the genomes of 10 soil-dwelling bacteriophages that they had isolated. Of the more than 1,600 genes that the team identified, about half are novel, that is, they don’t match any previously described genes in any other organism.

Science is full of amazing new frontiers. Some other amazing stuff: Thinking Slime Moulds – Tracking the Ecosystem Within Us – Retroviruses – Energy Efficiency of Digestion – One Species’ DNA Discovered Inside Another’s

Secret Life of Microbes

New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems

Nowhere is the principle of “strength in numbers” more apparent than in the collective power of microbes: despite their simplicity, these one-cell organisms–which number about 5 million trillion trillion strong (no, that is not a typo) on Earth–affect virtually every ecological process, from the decay of organic material to the production of oxygen.

But even though microbes essentially rule the Earth, scientists have never before been able to conduct comprehensive studies of microbes and their interactions with one another in their natural habitats.
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Because microbes are an ecosystem’s first-responders, by monitoring changes in an ecosystem’s microbial capabilities, scientists can detect ecological responses to stresses earlier than would otherwise be possible–even before such responses might be visibly apparent in plants or animals, Rohwer said.

Evidence that viruses–which are known to be ten times more abundant than even microbes–serve as gene banks for ecosystems. This evidence includes observations that viruses in the nine ecosystems carried large loads of DNA without using such DNA themselves. Rohwer believes that the viruses probably transfer such excess DNA to bacteria during infections, and thereby pass on “new genetic tricks” to their microbial hosts. The study also indicates that by transporting the DNA to new locations, viruses may serve as important agents in the evolution of microbes.

Bacteria Can Transfer Genes to Other Bacteria

From page 115 of Good Gems, Bad Germs:

Microbiologists of the 1950’s did not appreciate the stunning extent to which bacteria swap genes… In 1959 Japanese hospitals experience outbreaks of multidrug-resistant bacterial dysentery. The shigella bacteria, which caused the outbreaks, were shrugging off four different classes of previously effective antibiotics: sulfonamides, streptomycins, chloramphenicols, and tetracyclines… In fact, the Japanese researches found it quite easy to transfer multidrug resistance from E. coli to shingella and back again simply by mixing resistant and susceptible strains together in a test tube.