In Boston
Harbor, microbes clean up
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Two centuries
after the Boston Tea Party, a lot more than tea
has accumulated on the floor of Massachusetts
Bay-and much of it is anything but potable. Now
scientists have some good news for Boston Harbor.
A new study finds that bacteria can degrade toxic
petroleum byproducts in the bay's sediment, despite
its lack of oxygen. What is true in the laboratory
is also true in nature, the researchers found.
In the laboratory, certain bacteria degrade substances
known as PAHs through a process called 'anaerobic'
breakdown, in which sulfate replaces oxygen. This
process, the researchers suggest, also occurs
in Boston Harbor.
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Discovers Pollutant-eating Microbe
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ITHACA,
N.Y. -- Cornell University microbiologists, looking
for bioremediation microbes to "eat"
toxic pollutants, report the first field test
of a technique called stable isotopic probing
(SIP) in a contaminated site. And they announce
the discovery and isolation of a bacterium that
biodegrades naphthalene in coal tar contamination.
Although naphthalene is not the most toxic component
in coal tar, the microbiologists say their discovery
might eventually help to speed the cleanup of
hundreds of 19th and 20th century gasworks throughout
the United States where the manufacture of gas
from coal for homes and street lighting left a
toxic legacy in the ground.
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Microbe Cleans Up Wastewater
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Scientists have
discovered a microbe in Yellowstone National Park
that could be used to clean up wastewater, providing
an economical and natural way for paper and clothes
manufacturers to treat water before releasing
it back into rivers and streams. The microbe itself
would not be used in the cleanup. Instead, scientists
extract a protein from the microbe and add it
directly to industrial wastewater. The protein
breaks down hydrogen peroxide, which is often
used to bleach clothes and paper before they're
dyed or to sterilize paper food packages such
as juice boxes.
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Microbe Munches Coal Pollutants
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In
a 40-year old dump in Upstate New York, scientists
have found a microbe busy at work cleaning up
man's toxic messes. The newly discovered microbe
breaks down naphthalene in coal tar, a residue
left behind from the production of gas from coal
for street lamps and homes in the 19th and 20th
centuries. Chemicals from coal tar can contaminate
groundwater and there are hundreds of these potentially
hazardous sites throughout the United States.
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Microbe that breaks down metals
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Scientists have determined the genome sequence
of a microbe that has the potential to help remove
pollutants from the environment. Found in soil
and sediment worldwide, the bacterium transforms,
or reduces, metals like iron and uranium, causing
them to drop out of groundwater. The bacterium,
Shewanella oneidensis, could potentially be used
to clean up run-off from copper mines. The research
is part of an ongoing effort supported by the
US Department of Energy to investigate microbes
that may help solve environmental problems. Just
as humans inhale oxygen and exhale carbon dioxide,
the bacterium metabolizes metals and changes their
chemical structures by giving them electrons.
In their new form, the toxins precipitate out
of groundwater and can be isolated. |
Implications of Harmful Microalgae
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Worldwide increases
in the frequency and spatial extent of blooms
of harmful marine microalgae and heterotrophic
dinoflagellates suggest that these species are
becoming an increasingly important influence on
year class strength of marine fishes through both
direct and indirect mechanisms. Impacts on fish
populations from harmful marine microalgae and
heterotrophic dinoflagellates have been considered
primarily from the limited view of acute or lethal
influences. Accumulating evidence indicates that
insidious sublethal and chronic impacts to both
fish and human health from these organisms, such
as long-term behavior alteration, increased susceptibility
to cancers and other diseases, depressed feeding,
and impaired reproduction, may be substantial
and pervasive.
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Helping microbes battle pollutants
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The environmentalists
of the future are microbes that could rid the
earth of toxins like PCBs. In a new study, scientists
have revealed the details of a 'bottleneck' that
prevents some bacteria from converting PCBs-chemicals
used to make lubricants and coolants-into smaller,
less harmful molecules. The information could
lead to improved strategies for using microscopic
organisms to eliminate industrial pollutants.
Although the existence of bottlenecks isn't news
to researchers, the study describes for the first
time the crystal structures of the molecules involved
in logjams. The bacteria in the study were a type
of Burkholderia, one of many microbes that can
digest PCBs.
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Key player in global warming
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The unsung
heroes of the global carbon cycle are methanogens-microbes
at the bottom of the food chain who break down
the waste products of other organisms and release
methane gas into the atmosphere. Scientists have
now sequenced one of the most versatile methanogens,
an organism called Methanosarcina acetivorans.
Methanosarcina species live in oil wells, sewage
lagoons, trash dumps, decaying leaves, stream
sediments, and the stomach of cows, among other
places. They subsist on a diverse menu of energy
sources, including acetate. With the genome sequenced,
researchers have begun to search for genes responsible
for the organism's capacity to adapt and break
down a variety of waste products.
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A Hope For Oil Spill Bioremediation
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A recently
published article in Environmental Microbiology
reveals that indigenous microbiota of the Galician
shore is readily able to degrade crude oil. Scientists
from the Estación Experimental del Zaidín
(Spanish Council for Research, CSIC) in Granada
investigated in situ crude oil degradation after
the Prestige oil spill in November 2002. After
a spill, hydrocarbons are subjected to physicochemical
processes such as evaporation or photochemical
oxidation which produce changes in oil composition.
But the most important process acting on the spilled
oil is biodegradation. It is well established
that most crude oils are biodegradable to a great
extent, especially components as short linear
alkanes or simple aromatic hydrocarbons. However,
the heavy fraction, made of long-chain saturated
and polyaromatic hydrocarbons and a considerable
fraction of asphaltenes and resins, is generally
recalcitrant to degradation.
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Got a Toxic Mess? Call in the Microbes
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Chlorinated
solvents are nasty chemicals. But in the 1960s
and 1970s, before anyone realized just how nasty
they were, the United States government and some
industrial manufacturers used the solvents freely,
often dumping the leftovers in landfills or "out
the back door." Today, the solvents are some
of the most prevalent contaminants in groundwater
in the United States. The chemicals are thought
to cause cancer, and they're expensive to clean
up. But oddly enough, some bacteria are already
cleaning them up. These microbes live in soil
and groundwater, and they "eat" the
solvents, turning them into harmless substances.
The federal government and some private companies
are using the bacteria, called Dehalococcoides,
to clean up toxic messes by putting them en masse
into groundwater at contaminated sites.
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Cleaning Up Arsenic
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By adding genes
to common weeds, scientists have created a new
tool for cleaning up environmental toxins: Plants
that take up arsenic from the soil and sequester
it in their leaves, where the pollutant can later
be removed. One application would be to remove
dangerous concentrations of arsenic that leach
into drinking water. The researchers added two
bacterial genes to the weed Arabidopsis thaliana,
which is the laboratory mouse of plant genetics.
The first bacterial gene helps convert arsenic
from soil to a form that can be 'sucked up' and
stored. The second gene helps the plant detoxify
heavy metals and accumulate the molecules in its
leaves.
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Microorganism
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A microorganism or microbe is an organism that
is microscopic (invisible to the naked eye). Microorganisms
are often described as single-celled, or unicellular
organisms; however, some unicellular protists
are visible to the naked eye, and some multicellular
species are microscopic. The study of microorganisms
is called microbiology. Microorganisms can be
found almost anywhere in the taxonomic organisation
of life on the planet. Unicellular organisms carry
out all the functions of life. Bacteria and archaea
are almost always microscopic, whilst a number
of eukaryotes are also microscopic, including
most protists and a number of fungi. Unicellular
species are those whose members consist of a single
cell throughout their life cycle. This qualification
is significant since most multicellular organisms
consist of a single cell at the beginning of their
life cycles. Unicellular organisms usually contain
only a single copy of their genome when not undergoing
cell division, although some organisms have multiple
cell nuclei. |
Super Microbe Cleans Up Uranium
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During the Cold War, the United States produced
uranium for its nuclear weapons at Rifle Mill
in Western Colorado. The mine closed in 1972,
but the uranium has caused lasting effects on
the area, despite clean-up efforts. Uranium remains
underground today, and radioactive metal from
the site is still contaminating groundwater that
eventually flows into the Colorado River. But
there may be a solution that's natural and efficient.
Some microbes in the soil change metals such as
uranium from a dangerous, soluble form to an insoluble
form that falls out of the groundwater, where
it could be collected and safely removed. The
microbes live in the ground, and they can be stimulated
to grow naturally by adding vinegar to the soil.
One such microbe is Geobacter sulfurreducens.
Researchers funded by the U.S. Department of Energy
have used the microbe to reduce uranium in the
water at Rifle Mill by over 70 percent. And further
research this past summer reduced uranium in water
at the site by 90 percent. |
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