Effective imitation: chitinase inhibition by chitobiose and chitotriose thiazolines.
Image:
Di- and trisaccharide analogues of the oxazoline intermediate formed during enzymatic hydrolysis of chitin were found to be potent inhibitors of chitinase A.
[Credit: Angewandte Chemie, Wiley-VCH].
Synthetic Sea Shells
Scientists have made synthetic ‘sea shells’ from a mixture of chalk and polystyrene cups - and produced a tough new material that could make our homes and offices more durable.
DNA Repair
Mouse work: New insights on a fundamental DNA repair mechanism.
Chemicals that eased one environmental problem may
worsen another
Forests are being damaged by acid
rain, which contains a corrosive ingredient that may result from
the breakdown of chemicals introduced to help protect Earth's
ozone layer.
[Credit: Wikimedia Commons]
Chemicals that helped solve a global environmental
crisis in the 1990s - the hole in Earth's protective ozone layer - may
be making another problem - acid rain - worse, scientists are
reporting. Their study on the chemicals that replaced the
ozone-destroying chlorofluorocarbons (CFCs) once used in aerosol spray
cans, air conditioners, refrigerators, and other products, appears in
ACS' Journal of Physical Chemistry A, a weekly publication.
Jeffrey Gaffney, Carrie J. Christiansen, Shakeel S.
Dalal, Alexander M. Mebel and Joseph S. Francisco point out that
hydrochlorofluorocarbons (HCFCs) emerged as CFC replacements because
they do not damage the ozone layer. However, studies later suggested
the need for a replacement for the replacements, showing that HCFCs
act like super greenhouse gases, 4,500 times more potent than carbon
dioxide. The new study adds to those concerns, raising the possibility
that HCFCs may break down in the atmosphere to form oxalic acid, one
of the culprits in acid rain.
They used a computer model to show how HCFCs could
form oxalic acid via a series of chemical reactions high in the
atmosphere. The model, they suggest, could have broader uses in
helping to determine whether replacements for the replacements are as
eco-friendly as they appear before manufacturers spend billions of
dollars in marketing them.
Soil contains microbes that are
increasingly resistant to antibiotics, a finding that could have
broad consequences to public health.
[Credit: iStock]
A team of scientists in the United Kingdom and the
Netherlands are reporting disturbing evidence that soil microbes have
become progressively more resistant to antibiotics over the last 60
years. Surprisingly, this trend continues despite apparent more
stringent rules on use of antibiotics in medicine and agriculture, and
improved sewage treatment technology that broadly improves water
quality in surrounding environments. Their report appears in ACS'
bi-weekly journal Environmental Science and Technology.
David Graham and colleagues note that, although
scientists have known for years that resistance was increasing in
clinical situations, this is the first study to quantify the same
problem in the natural environment over long time-scales. They express
concern that increased antibiotic resistance in soils could have broad
consequences to public health through potential exposure through water
and food supplies. Their results "imply there may be a progressively
increasing chance of encountering organisms in nature that are
resistant to antimicrobial therapy."
The study involved an analysis of 18 different
antibiotic resistance genes (ARGs) to four different classes of
antibiotics in soil samples collected in the Netherlands from 1940 to
2008. ARGs are genes chosen to assess potential changes in resistance
in microbes. Using data from sites around the Netherlands, the
scientists found increasing levels in 78 percent of the ARG tested,
clearly indicating increased potential for resistance over time.
Because soil samples were only collected from the Netherlands, the
scientists conclude their report by suggesting that further studies
need be performed around the world so that the scope and possible
ramifications of their results can be better understood.
Supermarket lighting enhances nutrient level of
fresh spinach
Spinach on display under 24-hour
light in supermarkets actually gains in content of some nutrients.
[Credit: Marc Villalobos, USDA-ARS]
Far from being a food spoiler, the fluorescent
lighting in supermarkets actually can boost the nutritional value of
fresh spinach, scientists are reporting. The finding could lead to
improved ways of preserving and enhancing the nutritional value of
spinach and perhaps other veggies, they suggest in a study in ACS'
bi-weekly Journal of Agricultural and Food Chemistry.
Gene Lester, Donald J. Makus, and D. Mark Hodges
note that fresh spinach is a nutritional powerhouse, packed with
vitamin C, vitamin E, folate (a B vitamin), and healthful carotenoid
antioxidants. Supermarkets often display fresh spinach in clear
plastic containers at around 39 degrees Fahrenheit in showcases that
may be exposed to fluorescent light 24 hours a day. Lester, Makus, and
Hodges wondered how this continuous light exposure might affect
spinach's nutritional value.
The scientists exposed fresh spinach leaves to
continuous light or darkness during simulated retail storage
conditions for three to nine days. Spinach stored in light for as
little as three days had significantly higher levels of vitamins C, K,
E, and folate. They also had higher levels of the healthful
carotenoids (plant pigments) lutein and zeaxanthin. During continuous
light exposure after nine days, levels of folate increased between 84
and 100 percent, for instance. Levels of vitamin K increased between
50 and 100 percent, depending on the spinach variety tested. By
contrast, spinach leaves stored under continuous darkness tended to
have declining or unchanged levels of nutrients, the scientists say.
For the first time, ion traps were used to measure super heavy elements.
The picture shows the Penning trap, which is part of the Shiptrap experiment.
[Photo: G. Otto, GSI]
|
Physics - Fundamental
Research
Quantum Mechanics at Work in Photosynthesis
A team of chemists have made a major contribution to the emerging field of quantum biology, observing quantum mechanics at work in photosynthesis in marine algae.
Ultra-cold Chemistry
First direct observation of exchange process in quantum gas.
ATP Hydrolysis
Researchers determine how ATP, molecule bearing 'the fuel of life,' is broken down in cells. Breakthrough reveals that unleashing the power within requires another critical element for life: Water.
A new technique to study protein
dynamics in living cells has been created by a team
of University of Illinois scientists, and evidence
yielded from the new method indicates that an in
vivo environment strongly modulates a protein’s
stability and folding rate.
[Credit: Simon Ebbinghaus]
Optical Thermophoresis
A hot road to new drugs. Efficient identification of drug candidates.
|
Chemistry & Medicine
Calcineurin
Scientists identify critical enzyme in healthy heart function.
Water droplets shape graphene nanostructures
Graphene - a single-atom-thick sheet of carbon, like those seen in pencil marks - offers great potential for new types of nanoscale devices, if a good way can be found to mold the material into desired shapes.
'Microfluidic palette' may paint clearer picture of biological processes.
Image:
This is the NIST microfluidic palette. The mixing area is the pin-sized chamber bordered by three holes in the center of the top layer [Image by G. Cooksey, NIST].
Johns Hopkins engineers have invented a
method that could be used to help figure out how cancer
cells break free from neighboring tissue, an "escape" that
can spread the disease to other parts of the body [Diagram by Peter Searson].
|
Chemistry & Environment
Greenhouse Gases
Study documents reaction rates for three chemicals with high global warming potential.
Black Carbon Aerosols
Black carbon a significant factor in melting of himalayan glaciers.
PCB Contamination at the Summit
White, but not pure: Even the snow on Aconcagua Mountain in the Andes is polluted with PCBs. An international team of researchers detected low concentrations of these toxic, carcinogenic chlorine compounds in samples taken from America’s highest mountain.
Ancient Ocean Chemistry
New picture of ancient ocean chemistry argues for chemically layered water. Stratified marine basin sheds new light on early animal evolution, UC Riverside scientists say.
First direct chemical fingerprint of an exoplanet orbiting a sun-like star
Such 'chemical fingerprinting' is a key technique in
the search for habitable planets around other stars.
Image: HR 8799 system.
[Image source: MPIA/W. Brandner]
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