140 years since its discovery, and despite the best endeavours of many scientists, helium, the lightest of the 'noble' gases, still stubbornly refuses to enter into any chemical alliance.
Now a new glimmer of hope has emerged from poland as a chemist at the university of warsaw has calculated that two new compounds containing a helium-oxygen bond could be formed.
[Image by The Polish Journal of Chemistry /
University of Warsaw]
Glowing Results Pitt Researchers Use Fluorescence to Develop Fast, Simple Method for Detecting Mercury in Fish and Dental Fillings.
Fluorogenic detector glows bright green when in contact with mercury and could be used onsite.
A team of researchers led by Boston College Prof. Amir H. Hoveyda and MIT Prof. and Nobel laureate Richard R. Schrock have discovered a new class of catalysts for the powerful olefin metathesis reaction, illustrated here, which transforms simple molecules into complex ones. The process is critical to new research in medicine, biology and materials science
[Illustration courtesy of Nature].
PNAS study describes the new "chemistrode," which is analogous to an electrode.
Image by Ismagilov Lab, University of Chicago
Physics - Fundamental
Putting an end to turbulence
Whether in oil pipelines or city water mains - scientists from the Max Planck Institute for Dynamics and Self-Organization have discovered that turbulent flow is not stable.
More than a century ago, the development of the earliest
motion picture technology made what had been previously thought "magical"
a reality: capturing and recreating the movement and dynamism of the
world around us. A breakthrough technology based on new concepts has
now accomplished a similar feat, but on an atomic scale by allowing,
for the first time, the real-time, real-space visualization of
fleeting changes in the structure and shape of matter barely a
billionth of a meter in size.
[Credit: Nano Letters; images and diagram produced at Caltech.]
Microcapsules act as "roach motel" to kill
Researchers are reporting
development of antibacterial microcapsules that attract, capture,
and kill harmful bacteria.
Credit: Queensland Government
Researchers in New Mexico and Florida are reporting
development of microscopic particles that act as chemical booby traps
for bacteria. The traps attract and kill up to 95 percent of nearby
bacteria, including microbes responsible for worrisome hospital-based
infections. The scientists describe their discovery as micro-sized "roach
motels" for harmful bacteria. Their study went online November 24 in
the premiere issue of ACS Applied Materials & Interfaces,a new monthly
journal. It is scheduled for the January 28 print edition.
In the report, David G. Whitten of the University
of New Mexico and Kirk S. Schanze of the University of Florida,
working together with a team of faculty and graduate student
collaborators, point out that bacterial contamination of medical
devices causes up to 1.4 million deaths per year. In addition,
bacteria are becoming more resistant to standard disinfection methods.
Scientists also are increasingly concerned about the possibility of
intentional release of harmful bacteria by terrorists. As a result,
researchers are attempting to develop new and improved methods of
The New Mexico and Florida groups describe an
advance toward this goal. It involves the development of
light-activated, hollow microcapsules composed of an organic
conducting polymer. The antibacterial microcapsules can attract,
capture, and kill bacteria. In controlled laboratory tests, the
researchers exposed the capsules to either Pseudomonas aeruginosa, one
of the deadliest and most common hospital-based pathogens, or Cobetia
marina, a type of bacterium that fouls the hulls of ships and other
marine equipment. After one hour of light exposure, the
light-activated capsules killed more than 95 percent of the exposed
bacteria, the researchers say. The microcapsules can be applied to a
variety of surfaces, including medical equipment, they add. - MTS
Key advance toward treatment for most common
adult form of muscular dystrophy
Scientists are reporting a
critical first step toward development of a long sought drug for
myotonic muscular dystrophy (MMD).
Credit: American Chemical Society
Scientists in New York are reporting a critical
first step toward development of a long-sought drug to treat myotonic
muscular dystrophy (MMD), the most common form of muscular dystrophy
in adults. MMD affects about 1 in 8,000 people. Their findings are
scheduled for publication in the November 8 issue of ACS' weekly
Journal of the American Chemical Society.
In the study, Benjamin Miller and colleagues point
out that MMD differs from typical hereditary diseases. They result
from mutated DNA in genes that encodes an erroneous message that RNA
picks up and passes along. As a result, cells produce faulty proteins.
Those proteins disrupt cells' activity and cause symptoms of the
disease. Rather, MMD is caused by wayward or "toxic" strands of RNA.
The researchers describe discovery of a family of
drug-like molecules that target the errant strands of RNA, preventing
production of the defective protein. The discovery, they said,
provides scientists for the first time with substances that target the
root cause of MMD and represent molecules that could be developed into
drugs. They note that drugs more commonly target DNA or proteins, with
the RNA approach offering a different and potentially valuable route
to developing new medications for certain diseases. - JS
Toward healthier bread and other whole grain
Bread, pasta, and other foods made from whole
grains - known to help protect against heart disease, cancer and
diabetes - may get even healthier in the future. Scientists in Europe
collaborating in the European Union HEALTHGRAIN project are reporting
the largest study to date comparing nutrient levels in the world's
different grain varieties, which could lead to the development of
healthier varieties of grain and grain-based foods, they say. Their
findings will be described in a group of papers scheduled for the
November 26 issue of the ACS' Journal of Agricultural and Food
Chemistry, a bi-weekly publication.
In the new study, Peter R. Shewry and colleagues
point out that whole grain foods, including wheat, rye and oats, have
been widely touted in recent years for having greater health benefits
than refined grains. Health-promoting ingredients in whole grains
include fiber, antioxidants, folate, and other plant chemicals. As
nutrient levels can vary from grain to grain, however, it is unclear
which grain varieties pack the most nutritional punch, the researchers
To find out, the scientists grew 150 wheat
varieties used for bread-making and 50 other small-grain varieties (including
oats, rye, and barley) on a single farm in Hungary over a one year
period. The grains, grown from lines originating worldwide, were then
harvested, milled, and analyzed for a range of plant chemicals and
fiber components considered to have health benefits. The researchers
identified grain varieties with high levels of healthy components that
could be used to breed new, nutrient-rich varieties of grain for
healthier whole grain foods.
Gene "silencing" may improve success of islet
cell transplants for diabetes
Gene silencing shows promise for
improving the effectiveness of islet cell (shown) transplants for
Scientists in Tennessee are reporting that a gene
therapy technique called "gene silencing" shows promise for improving
the effectiveness and expanded use of transplants of insulin-producing
cells to treat diabetes. The study is scheduled for the December 1
issue of ACS' Molecular Pharmaceutics, a bi-monthly journal.
In the new study, Ram Mahato, Guofeng Cheng, and
Lin Zhu point out that transplantation of the pancreas's insulin
producing cells, called islet cells, has great potential for treating
patients with insulin-dependent diabetes. However, the procedure
currently is ineffective for most people due to a tendency of the
body's immune system to reject transplanted cells. Studies by others
indicate that a specific enzyme, caspase-3, plays a key role in
carrying-out this destructive process.
To address this problem, the scientists genetically
modified islet cells in the laboratory to turn off, or "silence" the
gene responsible for producing caspase-3. When the modified cells were
transplanted into the kidneys of mice with insulin-dependent diabetes,
the blood glucose levels of the mice became normal for up to 32 days,
the scientists say. When the cells were removed, the blood glucose
levels of the mice returned to high levels similar to
pre-transplantation levels, confirming that the transplanted cells
were functional and effective, the researchers say. - MTS
Concerns on mercury emissions may foster new
$500 million per year industry
Proposed government regulations limiting emissions
of mercury from electricity-generating stations may foster development
of a new half-billion-dollar per year industry offering technology for
removing mercury from power plant smokestacks, according to an article
scheduled for the November 24 issue of Chemical & Engineering News,
ACS' weekly newsmagazine.
In the article, C&EN Senior Correspondent Marc
Reisch points out that mercury is a toxic metal that can cause nerve
damage and birth defects in humans. The nation's 1,100 coal-burning
power plants spew 48 tons of mercury into the air each year, posing an
invisible but serious public health hazard, the article notes.
To reduce that threat, federal regulators have
proposed new restrictions on mercury emissions from electric power
plants. When they do go into effect, suppliers of environmental
technologies designed to reduce mercury emissions expect a future
market of $500 million a year or more. One of the most promising
mercury removal technologies is activated carbon, which can reduce
mercury emissions by 90 percent or more, according to the article. But
new and improved technologies for mercury removal are under
development, including catalysts made of gold, platinum, or titanium
dioxide. The payoff could mean a sizable new source of sales and
income for some suppliers, the article notes.
Toward a new generation of paper-thin
This paper-thin cylinder -
composed of carbon nanotubes - emits sound in all directions.
Image by the American Chemical
In research that may redefine ear buds, earphones,
stereo loudspeakers, and other devices for producing sound,
researchers in China are reporting development of flexible
loudspeakers thinner than paper that might be inserted into the ears
with an index finger or attached to clothing, walls, or windows. Their
report on what may be the world's thinnest loudspeakers, made from
transparent carbon nanotube films, is scheduled for the December 10
issue of ACS' Nano Letters, a monthly journal.
Kaili Jiang, Shoushan Fan, and colleagues note that
most of today's loudspeakers are relatively bulky, complex, and
inflexible, consisting of a permanent magnet fixed to a voice coil and
a cone. To meet the growing demand for smaller speakers for portable
digital consumer electronics devices, manufacturers need new
technology, they say.
The scientists describe the development of
super-thin carbon nanotube (CNT) films - 1/1,000th the width of a
single human hair - that are capable of transmitting music and other
sounds. In laboratory tests, the researchers mounted a thin CNT film
onto two electrodes to form a simple loudspeaker. The speaker produced
sound with the same excellent quality as conventional loudspeakers,
but without magnets and moving components, the researchers say. They
also demonstrated that the flexible film could be used just as
effectively to play music from an iPod and while pasted to a flexible,
waving flag (please see accompanying video of the article).
"These CNT thin film loudspeakers are transparent,
flexible, and stretchable, which can be tailored into many shapes and
mounted on a variety of insulating surfaces, such as room walls,
ceilings, pillars, windows , flags, and clothes without limitations.
Furthermore, CNT thin films can also be made into small area devices,
such as earphones and buzzers. There is no doubt that more and more
applications will be developed as time goes on. This technique might
open new applications of and approaches to manufacturing loudspeakers
and other acoustic devices."- MTS
A faster test for the food protein that triggers
Researchers in Spain and the United Kingdom are
reporting development of a faster test for identifying the food
protein that triggers celiac disease, a difficult-to-diagnose
digestive disease involving the inability to digest protein called
gluten that occurs in wheat, oats, rye, and barley. The finding could
help millions of people avoid diarrhea, bloating, and other symptoms
that occur when they unknowingly eat foods containing gluten. The
study is scheduled for the December 15 issue of Analytical Chemistry,
a semi-monthly journal.
In the new report, Alex Fragoso, Ciara O'Sullivan
and colleagues note that patients with celiac disease can avoid
symptoms by avoiding foods that contain gluten. Doing so can be tricky,
however, because gluten may be a hidden ingredient in unsuspected
foods, such as soy sauce, canned soups, and licorice candy. Some
prepared foods list gluten content on package labels, but identifying
its presence remains difficult and time-consuming.
The scientists describe development of a new sensor
that detects antibodies to the protein gliadin, a component of gluten.
Laboratory tests showed that it is superior to the so-called
enzyme-linked immunosorbent assay (ELISA), now the standard test for
gliadin. It took the new test barely 90 minutes to detect gliadin in
the parts per billion range, compared to 8 hours for the ELISA test.
Although both tests were equally accurate, the new sensor would be
easier to use at food manufacturing plants, the researchers note. -
"Powerhouses" from living cells power new
Scientists have developed a
stamp-sized sensor for detecting hidden explosives. The sensor is
powered by mitochondria, which provide energy to living cells.
Image by the American Chemical
Researchers in Missouri have borrowed the
technology that living cells use to produce energy to develop a tiny,
self-powered sensor for rapid detection of hidden explosives. The
experimental sensor, about the size of a postage stamp, represents the
first of its kind to be powered by mitochondria, the microscopic "powerhouses"
that provide energy to living cells, the researchers say. Their study
is scheduled for the November 26 issue of the weekly Journal of the
American Chemical Society.
In the new study, Shelley Minteer, Marguerite
Germain, and Robert Arechederra point out that today's explosives
detectors are expensive, bulky, and complex. Society needs smaller,
cheaper, simpler detection devices, based on technology that perhaps
could be incorporated into cell phones and portable digital music
players, the researchers suggest.
The scientists describe development of an
experimental sensor built from a special biofuel cell, essentially a
battery-like device consisting of a thin layer of mitochondria
sandwiched between a carbon-based electrode and a gas-permeable
electrode. In laboratory studies using nitrobenzene as a test
compound, the sensor showed a significant boost in electrical power in
the presence of the substance, demonstrating the sensor's potential
for detecting TNT and related explosives, the researchers say. - MTS
Healthful plant nutrients also found in meat and
Beneficial nutrients called
phytoestrogens found in plant-based food are also found in meats,
seafood and soy products, according to a new study.
Counterintuitive as it may seem, those healthful
phytoestrogen nutrients that consumers usually associate with fruits
and vegetables also exist in foods of animal origin. After all, "phyto"
means "plant." Now the first comprehensive study of phytoestrogen
content in foods has identified the best sources of these nutrients.
The study is scheduled for the November 26 issue of ACS' bi-weekly
Journal of Agricultural and Food Chemistry.
In the study, Gunter G. C. Kuhnle, Laure Thomas and
colleagues point out that phytoestrogens have garnered increasing
attention for their beneficial role in preventing several diseases,
including osteoporosis, type-2 diabetes and certain cancers. But much
of the scientific research on these compounds has focused on their
occurrence in plant-based foods, which has led to an underestimation
of actual amounts people consume, the study says.
The researchers analyzed 115 foods of animal origin
and found that all food groups studied contained phytoestrogens.
Isoflavones - one of the three major classes of these compounds - were
considerably higher in soy-based foods. In fact, the amount of
phytoestrogens in soy-based infant formula was more than 300 times
higher than in normal infant formula. In animal products,
phytoestrogens are low when compared to foods containing soy, the
paper notes, but the range is similar to that of many commonly
consumed vegetables. - JS
In the face of growing environmental concerns and a
renewed interest in energy efficiency, the construction of homes and
businesses that emphasize "green" construction materials is on the
rise, according to an article scheduled for the November 17 issue of
Chemical & Engineering News, ACS' weekly newsmagazine.
In the two-part C&EN cover story, Senior Business
Editor Melody Voith notes that while green building materials were
once viewed as a trendy environmental statement focusing on natural or
recyclable items, these materials now are emerging as practical,
high-performance products that also provide energy efficiency. The
market for green building products and services was $12 billion in
2007 and experts project it to increase to $60 billion by 2010, the
Today, a "green building" usually refers to a
commercial building or home that has been certified as such by the
U.S. Green Building Council (USGBC) for its use of
environmentally-friendly materials, among other considerations. The
USGBC plans to release updated certification standards in 2009 that
emphasize lower energy use and reduced greenhouse gas emissions, the
article notes. The U.S. Department of Energy, meanwhile, assists
builders in making homes more energy efficient by publishing guideline
specifications for insulation, windows, ductwork, appliances, and
other items. Says one producer of construction materials, "All of a
sudden, green is becoming serious and growing up. It is a huge shift
in how buildings are designed and constructed."
New insights into thalidomide-birth defect
Scientists in Germany have discovered why the
medication thalidomide appeared safe in animal tests before going on
the market 50 years ago, only to cause perhaps the most extensive
outbreak of drug-induced birth defects in medical history. Their study
is scheduled for the December 1 edition of ACS' Molecular
Pharmaceutics, a bimonthly journal.
Jurgen Knobloch, Ulrich Ruther and colleagues note
that more than 10,000 children were born with severe birth defects
after drug regulators in Europe approved the medication for treating
nausea and vomiting in pregnant women. The drug, never approved for
that use in the United States, is available for certain conditions,
including multiple myeloma and leprosy. The birth defects outbreak
puzzled scientists because pre-marketing tests in lab mice and rats
showed no sign of a birth defect risk.
The researchers point out that those animals proved
to be resistant to thalidomide's adverse effects, and in the new study
they describe discovery of the biochemical basis for that resistance.
It involves a key difference between human embryonic cells and those
of mice. They found in mice cells advanced antioxidant defenses
compared to those in humans and other thalidomide-susceptible species.
Therefore, thalidomide is not able to induce the generation of large
quantities of damaging free radicals called superoxides in mouse
embryonic cells as it does in human embryonic cells (where subsequent
cell death is believed to be responsible for birth defects.) - JS
Scientists report that mouth
bacteria are responsible for creating the distinctive flavors of
certain foods, including some fruits and vegetables.
Scientists in Switzerland are reporting that
bacteria in the human mouth play a role in creating the distinctive
flavors of certain foods. They found that these bacteria actually
produce food odors from odorless components of food, allowing people
to fully savor fruits and vegetables. Their study is scheduled for the
November 12 edition of the ACS bi-weekly Journal of Agricultural and
In the study, Christian Starkenmann and colleagues
point out that some fruits and vegetables release characteristic odors
only after being swallowed. While scientists have previously reported
that volatile compounds produced from precursors found in these foods
are responsible for this 'retroaromatic' effect, the details of this
transformation were not understood.
To fill that knowledge gap, the scientists
performed sensory tests on 30 trained panelists to evaluate the odor
intensity of volatile compounds � known as thiols � that are released
from odorless sulfur compounds found naturally in grapes, onions, and
bell peppers. When given samples of the odorless compounds, it took
participants 20 to 30 seconds to perceive the aroma of the thiols �
and this perception persisted for three minutes. The researchers also
determined that the odorless compounds are transformed into the thiols
by anaerobic bacteria residing in the mouth � causing the
characteristic 'retroaromatic' effect. "The mouth acts as a reactor,
adding another dimension to odor perceptions," they explain. However,
the authors conclude, it is saliva's ability to trap these free thiols
that helps modulate the long-lasting flavors. - KSD
"Liquid mirror" advance may lead to better eye
exams, improved telescopes
Compared to a previous formula
for making liquid mirrors� (left), new materials show excellent
Credit: American Chemical Society
Scientists in Canada are reporting progress toward
a new type of "liquid mirror" - mirrors made with highly reflective
liquids - whose shape can be changed to provide superior optical
properties over conventional solid mirrors. The advance could lead to
improved instruments for diagnosing eye disease, more powerful
telescopes, and other applications, the researchers say. Their
research will be described in the November 25 issue of ACS' Chemistry
of Materials, a bi-weekly journal.
In the report, Anna Ritcey, Jean-Philippe Dery, and
Ermanno Borra note that "liquid mirrors" are not new. Scientists have
long recognized that these liquids could provide a low-cost,
easy-to-use alternative to solid mirrors for a variety of optical
applications while offering the potential for less image distortion.
Researchers have recently developed liquid-mirror telescopes that use
mercury as the reflective material. Mercury, however, is toxic and the
shape of the surface can't be deformed or adjusted.
The scientists describe development of a new type
of deformable "liquid mirror" composed of magnetic iron particles,
ethylene glycol (a component of automotive antifreeze), and a coating
of silver nanoparticles. These materials form a highly reflective
mirror whose shape can be changed by adjusting the voltage applied to
electromagnets placed below the liquid, allowing the user to fine-tune
the mirror's optical properties. In lab studies, the new material
showed better reflectivity and stability than current liquid-mirror
materials, the scientists say. - MTS
Scientists report that using
chitosan microspheres (above) could provide a safer alternative
for heparin removal after surgery.
Credit: Karolina Zazakowny and
Scientists in Poland are reporting development of a
potential new way to quickly remove the anticoagulant heparin from
patients' blood in order to avoid unwanted side effects that can
happen with the current use of that blood thinner. Their new polymer
material will be described in the December 8 issue of ACS'
Biomacromolecules, a monthly journal.
In the new study, Krzysztof Szczubialka and
colleagues point out doctors often want to remove heparin from the
blood of patients undergoing surgery or other procedures immediately
after completing the procedure. Leaving the heparin alone could lead
to unwanted bleeding. Doctors now eliminate heparin by giving patients
protamine, a drug that stops heparin's anticoagulant effects. However,
they are seeking a better drug because protamine carries a risk of
serious side effects.
The scientists describe development of a potential
new approach that involves use of microscopic beads of a polymer made
from modified chitosan, a material obtained from shellfish. In
laboratory tests, the beads reduced concentrations of heparin to
nearly zero within 10 minutes. - MTS
Laws and regulations intended to crack down on
terrorists, illicit drug manufacture, and other criminal activities
are stifling an elite cadre of individuals who pursue chemistry as a
hobby and have a home chemistry lab, according to an article scheduled
for the Nov. 10 issue of Chemical & Engineering News, ACS' weekly
In the article, C&EN Associate Editor Bethany
Halford notes that having a lab in the basement, garage, or backyard
shed was once a rite of passage for scientifically minded kids and a
relatively common hobby for science curious-adults. Some of these labs
have even produced significant contributions to chemistry, including
vulcanized rubber and aniline dyes, the article notes.
Now, in an ongoing battle against bomb-makers and
illegal methamphetamine labs, home-based chemistry is increasingly
coming under attack. Thousands of people who want to pursue chemistry
as a do-it-yourself hobby or home-school lesson must navigate through
a maze of federal, state, and local laws that target hazardous
substances - or run the risk of fines or laboratory shutdowns, the
article notes. "Not all of us are mad bombers or drug makers and we
would like to be able to practice our hobby in peace if there's a
reasonable way for us to figure out the guidelines," says one
authority on hobby chemists.
Researchers are reporting
record-high efficiency levels for a new generation of solar cells.
Credit: National Renewable Energy
Researchers in China and Switzerland are reporting
the highest efficiency ever for a promising new genre of solar cells,
which many scientists think offer the best hope for making the sun a
mainstay source of energy in the future. The photovoltaic cells,
called dye-sensitized solar cells or Gr�tzel cells, could expand the
use of solar energy for homes, businesses, and other practical
applications, the scientists say. Their study is scheduled for the
November 13 issue of ACS' The Journal of Physical Chemistry C, a
The research, conducted by Peng Wang and colleagues
- who include Michael Gr�tzel, inventor of the first dye-sensitized
solar cell - involves photovoltaic cells composed of titanium dioxide
and powerful light-harvesting dyes. Gr�tzel cells are less expensive
than standard silicon-based solar cells and can be made into flexible
sheets or coatings. Although promising, Gr�tzel cells until now have
had serious drawbacks. They have not been efficient enough at
converting light into electricity. And their performance dropped after
relatively short exposures to sunlight.
In the new study, researchers describe lab tests of
solar cells made with a new type of ruthenium-based dye that helps
boost the light-harvesting ability. The new cells showed efficiencies
as high as 10 percent, a record for this type of solar cell. The new
cells also showed greater stability at high temperatures than previous
formulas, retaining more than 90 percent of their initial output after
1,000 hours in full sunlight. - MTS
Tale of two snails reveals secrets about the
biochemistry of evolution
A study of two populations of
marine snails provides new insights into how evolutionary changes
works on the chemical level.
Image by The American Chemical
Researchers in Spain are reporting deep new
insights into how evolution changes the biochemistry of living things,
helping them to adapt to new environments. Their study, based on an
analysis of proteins produced by two populations of marine snails,
reveals chemical differences that give one population a
survival-of-the fittest edge for life in its cold, wave-exposed
environment. Their report is scheduled for the November 7 issue of ACS'
Journal of Proteome Research, a monthly publication.
In the new study, Emilio Rol�n-Alvarez and
colleagues note that scientists long have known that animals of the
same species can have different physical characteristics enabling them
to survive in different habitats. One famous example is the different
beak sizes and shapes that evolved in Darwin's finches, enabling the
birds to live on different foods in different habitats on the
Galapagos Islands. Until now, however, scientists knew little about
the invisible biochemical changes behind such adaptations.
To help fill those gaps, the scientists studied two
populations of marine snails that live only a few feet apart on the
Spanish coast. One group lives on the lower shore, typically submerged
in water and protected from large changes in temperature. The other
group lives on the upper shore exposed to daily changes in temperature,
humidity and other environmental conditions. Tests with mass
spectrometry showed major differences in about 12 percent of the
proteins in the snail, a subset of proteins that apparently enables
the snails to survive in different environmental conditions. - MTS
Tiny DNA tweezers can catch and release objects
Researchers in China are reporting development of a
new DNA "tweezers" that are the first of their kind capable of
grasping and releasing objects on-demand. The microscopic tweezers
could have several potential uses, the researchers note. Those include
microsurgery, drug and gene delivery for gene therapy, and in the
manufacturing of nano-sized circuits for futuristic electronics. Their
study is scheduled for the November 12 issue of the weekly Journal of
the American Chemical Society.
Zhaoxiang Deng and colleagues note that other
scientists have developed tweezers made of DNA, the double helix
molecule and chemical blueprint of life. Those tweezers can open and
close by responding to complementary chemical components found in
DNA's backbone. However, getting the tweezers to grasp and release
objects like real tweezers has remained a bioengineering challenge
The scientists describe development of a pair of
DNA tweezers composed of four DNA strands - three which act as the "arms."
In laboratory studies, the scientists showed that they could grab a
piece of target DNA in the arms of the tweezers and release it
on-demand using a controlled series of hydrogen bonding and pH changes.
The scientists used fluorescent gel imaging to confirm the
effectiveness of the tweezers' operation. - MTS
DNA fingerprinting method may thwart false
labeling of shark meat
A new DNA identification method
could thwart false labeling of shark species used in seafood.
Credit: Wikipedia Commons
Researchers in Spain are reporting that a new DNA
identification method could thwart false labeling of shark species
used in various seafood products, including the expensive Chinese
delicacy known as shark fin soup. Their study is scheduled for the
November 26 issue of ACS' Journal of Agricultural and Food Chemistry,
a bi-weekly publication.
Maria Blanco, Ricardo Perez-Martin, and Carmen G.
Sotelo note that consumption of shark meat appears to be on the rise
worldwide, with some seafood companies reportedly having substituted
cheaper shark species for more expensive species and incorrectly
labeling their products. European Union regulations now require
listing the species name on shark products to avoid fraud and to help
conserve certain shark species. However, a fast, reliable method for
distinguishing between different species of shark remains elusive.
The scientists describe the use of a relatively new
technique called forensically informative nucleotide sequencing (FINS),
in which DNA isolated from unknown biologic samples is compared to a
database of DNA markers from known species. In the new study, the
scientists collected DNA markers from nine different commercial
seafood samples containing shark meat and compared them to known DNA
markers from 23 different shark species. The scientists found that two
of the nine shark products analyzed had been labeled with incorrect
species names, demonstrating the effectiveness for the FINS method. -
Toward a safer, more effective method for
preserving museum specimens
Some of the most fascinating creatures ever to
inhabit the Earth can be seen today only in the form of preserved
museum specimens. Researchers now are reporting progress toward a
safer, more effective method of preserving these precious biological
specimens in order to prolong their study and enjoyment for future
generations, according to an article scheduled for the Nov. 3 issue of
Chemical & Engineering News, ACS' weekly newsmagazine.
In the article, C&EN Assistant Editor Carmen Drahl
notes that the most widely-used substances for long-term museum
conservation are solutions of alcohols, such as ethanol, and formalin,
a dilute solution of formaldehyde. Although used for centuries as
effective preservatives, these solutions have several disadvantages.
For example, alcohol is highly flammable and discolors specimens,
while formalin has been linked to cancer in animals and also causes
Scientists at the Smithsonian's National Museum of
Natural History in Washington, D.C. are now experimenting with a
promising new solution to help preserve its prized 24-foot long giant
squid specimen. Called "Novec," the transparent solution is a nontoxic,
non-flammable hydrofluoroether originally developed by 3M Corporation
for electronics industry applications. Novec works by forming a
chemical envelope around already preserved specimens, much like
repelling water from a car's surface by applying a fresh coat of wax.
Novec does not get cloudy over time, and unlike traditional
preservatives, it protects specimens from color changes. Thus, the
Smithsonian's giant squid has become an ongoing experiment in modern
preservation methods. "We're very interested in seeing how it will all
turn out," says one researcher.