Scientists Make First Nanoscale pH Meter
Found Between Biological Clock And Cancer
New Research May
Reduce Global Need For Nitrogen Fertilizers
Satellite to Aid
Education In Northeast India
Lighting Study Is Released
Puzzled By Sand Bacteria
Scientists Make First Nanoscale pH Meter
News Source: Rice University
Using unique nanoparticles that convert laser light into useful
information, Rice University scientists have created the world's
first nano-sized pH meter.
discovery, which appears online this week in the jour nal Nano
Letters, present s biologists with the first potential means of
measuring accurate pH changes over a wide pH range in real-time
inside living tissue and cells.
"Almost every biologist I speak with comes up with one or two things
they'd like to measure with this," said lead researcher Naomi Halas,
the Stanley C. Moore Professor of Electrical and Computer
Engineering, professor of chemistry and director of Rice's
Laboratory for Nanophotonics (LANP).
example, pH may be useful in determining whether or not some cancer
tumors are malignant. With current methods, a piece of the tumor
would need to be physically removed via biopsy - a painful and
invasive procedure - and visually evaluated under a microscope.
Halas said LANP's new nano-pH meter could be used instead as an
"optical biopsy" to measure the pH inside the tumor with nothing
more invasive than an injection.
Halas's LANP team created the pH sensor using nanoshells, optically
tuned nanoparticles invented by Halas. Each nanoshell contains a
tiny core of non-conducting silica that's covered by a thin shell of
metal, usually gold. Many times smaller than living cells,
nanoshells can be produced with great precision and the metal shells
can be tuned to absorb or scatter specific wavelengths of light.
form the pH sensor, Halas' team coated the nanoshells with
pH-sensitive molecules called paramercaptobenzoic acid, or pMBA.
When placed in solutions of varying acidity and illuminated, the
nanoshell-molecule device provides small but easily detectable
changes in the properties of the scattered light that, when
"decoded," can be used to determine the pH of the nanodevice's local
environment to remarkably high accuracy. Inspired by techniques
normally applied to image recognition, the team formulated an
efficient statistical learning procedure to produce the device
output, achieving an average accuracy of 0.1 pH units.
term "pH" was coined by the Danish chemist Søren Sørensen in 1909 as
a convenient way of expressing a solution's acidity. pH ranges from
one - the most acidic - to 14 - the most alkaline.
Co-authors on the paper include postdoctoral researchers Sandra
Bishnoi, now an assistant professor at the Illinois Institute of
Technology, and Muhammed Gheith; graduate students Christopher
Rozell and Carly Levin; Bruce Johnson, distinguished faculty fellow
of chemistry and executive director of the Rice Quantum Institute;
and Don Johnson, J.S. Abercrombie Professor of Electrical and
Computer Engineering and Statistics.
research was supported by the Department of Defense's
Congressionally Directed Medical Research Program, the Air Force
Office of Scientific Research, the Keck Foundation, the Robert A.
Welch Foundation and by Texas Instruments.
*Novel Connection Found
Between Biological Clock And Cancer
News Source: Dartmouth Medical School
Dartmouth Medical School geneticists have discovered that DNA damage
resets the cellular circadian clock, suggesting links among
circadian timing, the cycle of cell division, and the propensity for
Their work, reported June 29 in Science Express, the advance
electronic publication of Science, implies a protective dimension
for the biological clock in addition to its pacemaker functions that
play such a sweeping role in the rhythms and activities of life.
"The notion that the clock regulates DNA-damage input and that
mutation can affect the clock as well as the cell cycle is novel,"
says Jay Dunlap, professor and chair of genetics at DMS. "It
suggests a fundamental connection among circadian timing, cell cycle
progress, and potentially the origins of some cancers."
Dunlap is a co-author of the paper with DMS colleagues, Jennifer
Loros, professor of biochemistry, graduate student Christopher L.
Baker, and former students António M. Pregueiro and Qiuyun Liu.
team of Loros and Dunlap were among to first to delineate the
intricate web of clockwork genes, proteins and feedback loops that
drive circadian rhythms, working chiefly in the classic genetic
model organism Neurospora, the common bread mold.
gene (period-4) was identified over 25 years ago by a mutation that
affects two clock properties, shortening the circadian period and
altering temperature compensation. For this study, the researchers
cloned the gene based on its position in the genome, and found it
was an important cell cycle regulator. When they eliminated the gene
from the genome, the clock was normal, indicating that the mutation
interfered in some way with the clock, rather than supplying
something that the clock normally needs to run.
Biochemically, the mutation results in a premature modification of
the well understood clock protein, frequency (FRQ). The
investigators demonstrated that this was a direct result of action
by an enzyme, called in mammals checkpoint kinase-2 (CHK2), whose
normal role is exclusively in regulating the cell division cycle.
CHK2 physically interacts with FRQ; the mutation makes this
interaction much stronger. However, a mutant enzyme that has lost
its activity has no effect on the clock.
Normally CHK2 is involved in the signal response pathway that begins
when DNA is damaged and results in a temporary stoppage of cell
division until the damage is fixed. The researchers found that the
resetting effect of DNA damage requires the period-4 clock protein,
and that period-4 is the homolog, the Neurospora version, of the
mammalian checkpoint kinase.
Moreover, the clock regulates expression of the period-4 gene. This
closes a loop connecting the clock to period-4 and period-4 to the
clock and the cell cycle. The clock normally modulates expression of
this gene that encodes an important cell cycle regulator, and that
cell cycle regulator in turn affects not only the cell cycle but
also the clock.
Recent evidence in mammalian cells shows that other cell cycle
regulators physically interact with clock proteins. Loss of at least
one clock protein (mammalian period-2) is known to increase cancer
susceptibility. The coordination of the clock and cell division
through cell cycle checkpoints, supports the clock's "integral role
in basic cell biology," conclude the researchers." Their work can
help advance understanding of cancer origins as well as the timing
of anti-cancer treatment.
*New Research May
Reduce Global Need For Nitrogen Fertilizers
News Source: Biotechnology and Biological Sciences
Research published June 29 in the journal Nature reveals how
scientists at the John Innes Centre (JIC), Norwich and Washington
State University, USA have managed to trigger nodulation in legumes,
a key element of the nitrogen fixing process, without the bacteria
normally necessary. This is an important step towards transferring
nodulation, and possibly nitrogen fixation, to non-legume crops
which could reduce the need for inorganic fertilizers.
researchers, funded by the Biotechnology and Biological Sciences
Research Council (BBSRC), the Royal Society and the US National
Science Foundation, have used a key gene that legumes require to
establish the interaction with the nitrogen-fixing bacteria to
trigger the growth of root nodules, even in the absence of the
fixation of nitrogen by some plants is critical to maintaining the
health of soil as it converts the inert atmospheric form of nitrogen
into compounds usable by plants. Legumes, as used in this study, are
an important group of plants as they have the ability to fix
nitrogen – which they owe to a symbiotic relationship with
nitrogen-fixing bacteria in root nodules. Legumes are often used as
a rotation crop to naturally enhance the nitrogen content of soils.
Scientists have been working for a number of years to understand the
symbiosis between legumes and rhizobial bacteria, with the hope that
one day they can transfer this trait to crop plants, the majority of
which cannot fix nitrogen themselves.
Intensive crop agriculture depends heavily on inorganic fertilisers
that are often used to provide nutrients particularly nitrogen that
are critical for plant growth. The production of nitrogen
fertilisers requires a large amount of energy and is estimated to
constitute approximately 50 per cent of the fossil fuel usage of the
modern agricultural process. Inorganic fertilizers also cause
environmental problems associated with leeching into our water
Giles Oldroyd is the research leader at JIC. He said: “We now have a
good understanding of the processes required to activate nodule
development. The nodule is an essential component of this nitrogen
fixing interaction as it provides the conditions required for the
bacteria. Nodules are normally only formed when the plant perceives
the presence of the bacteria. The fact that we can induce the
formation of nodules in the plant in the absence of the bacteria is
an important first step in transferring this process to non-legumes.
If this could be achieved we could dramatically reduce the need for
inorganic nitrogen fertilizers, in turn reducing environmental
pollution and energy use. However, we still have a lot of work
before we can generate nodulation in non-legumes.”
Professor Julia Goodfellow, Chief Executive of BBSRC, commented:
“BBSRC is the principal funder of fundamental plant research in the
UK and commits millions of pounds a year to furthering our
understanding of basic plant biology. Such fundamental research may
seem disconnected from the every day world for many people but this
project shows how potentially important such science is. The
findings have the potential to lead to a practical application with
substantial economic impact for the UK.”
*Satellite to Aid
Education In Northeast India
Agartala, India (IANS) Jun 30, 2006
Students in India's northeast will soon have satellite-based
educational facilities available. Three states - Tripura, Mizoram
and Nagaland - will be included in the first phase of the hi-tech
facilities using the services of EDUSAT, a dedicated satellite for
education launched in 2004.
the first phase, the project will cover government-run schools and
it will be subsequently introduced in private schools.
"Educational programmes through satellite would reach some of the
most interior and inaccessible hilly areas of Tripura, Mizoram and
Nagaland through video-conferencing," said K.C. Bhattacharya,
director of the Northeastern Space Application Center.
There will be a hub and a studio each in the three states.
Tripura and Nagaland will each have 30 satellite educational
facilities and Mizoram 31.
"These resource centers will be located in blocks, higher secondary
and middle schools, district institutes of education and training,"
Bhattacharya told IANS.
Reception terminals will be installed in each center.
EDUSAT services will be made available in the remaining states of
the region - Assam, Manipur, Meghalaya, Arunachal Pradesh and Sikkim
- by the end of March 2007.
NESAC is coordinating with the ISRO for the launch of the project.
There will be specialized teachers at the uplink station or the hub
and lessons taught would reach hundreds of students in the remote
centers through satellite signals.
"The teachings in the studio can be seen and heard in the classrooms
on large screens or big television sets with cameras and audio
equipment available at both ends for communication," said Krishna
Dhan Nath, director of the State Council for Educational Research
"The teachers will be able to hear the students who will be visible
to all the other learners in various centers, creating an atmosphere
of a virtual classroom," he said.
new venture is expected to bring down the dropout rate among school
students in the region, besides helping teachers to enhance their
Indira Gandhi National Open University and ISRO have been jointly
working to develop a satellite-based educational network since 1993.
The EDUSAT was launched in 2004 by the Geosynchronous Satellite
project is being funded and coordinated by the human resource
development ministry and the department of space and technology.
*First Global Lighting
Study Is Released
Paris (UPI) Jun 30, 2006
first global survey of lighting uses and costs suggests the world's
electric bill would greatly decrease with a switch to efficient
lighting systems. The Paris-based International Energy Agency, which
conducted the study, said it found lighting is a major source of
Paul Waide, a senior IEA policy analyst and one of the report's
authors, told the BBC: "Nineteen percent of global electricity
generation is taken for lighting. That's more than is produced by
hydro or nuclear stations, and about the same that's produced from
study notes the incandescent light bulb -- developed about 125 years
ago -- still produces nearly half of the light used in homes around
the world. But, scientists say, incandescent bulbs are very
inefficient, converting only about five percent of the energy they
receive into light.
However the biggest consumers of electricity are the fluorescent
tube, the efficiency of which can vary between 15 percent and 60
percent, and halogen lighting, which the IEA says is the least
efficient of all commonly used lighting systems.
study concludes new lighting policies and individual action could
slash 38 percent from the world's lighting bill by 2030.
*Scientists Puzzled By
Mount Pleasant (UPI) Jun 30, 2006
U.S. scientists say bacteria forcing the closure of many beaches may
not be coming from people, animals, or sewage -- but might be
produced in the sand. Researchers at Central Michigan University say
they have found E. coli can live and thrive in beach sand without a
warm-blooded host. While not necessarily a threat to human health,
E. coli has been used as an indicator of other pathogens in
excrement, such as viruses, the Duluth (Minn.) News Tribune
Central Michigan University Microbiologist Elizabeth Alm says E.
coli has been found in Lake Huron sand with no fecal matter from
people, birds or animals.
says her finding means scientists need to create a new indicator for
harmful pathogens in water and might also indicate dangerous
organisms are thriving in beach sand.
"Geese and gulls and diapers may still be sources of some fecal
matter and some E. coli, but we clearly can have E. coli without any
of them," She said. "We need to do a lot more research to see what
else may be naturalized in the sand."
findings appear in the Journal of Great Lakes Research.