Back to Table of contents

Primeur weekly 2014-02-10

The Cloud

European Cloud Testing Environment to be offered free of charge during 2014 ...

IBM opens access to SaaS portfolio to help African Universities with next-generation IT skills ...

IBM and Actifio add powerful new data virtualization solutions to IBM Cloud portfolio ...

Numericable Group teams with IBM's SoftLayer to develop a unique High Performance Cloud offer in France ...

HP Autonomy extends market-leading eDiscovery platform to the Cloud ...

IBM's SoftLayer and DataHotel help Japanese companies expand globally ...

IBM fuels innovation and entrepreneurship in Africa ...

Oracle extends the power of modern HR in the Cloud with updates to Oracle HCM Cloud ...

Desktop Grids

New CONVECTOR project studies mechanical engineering problems ...

EuroFlash

MSc in High Performance Computing organized at Edinburgh Parallel Computing Centre ...

PRACE Preparatory Access passes 3-year cap in bloom ...

EPSRC calls for Quantum Technology Hubs to put UK in super position ...

2nd International Conference on Research Infrastructures to launch Call for Contributions ...

Netherlands joins international Elixir Consortium on biological data ...

USFlash

IBM Brings Watson to Africa ...

SGI and Cognilytics partner to bring advanced analytics to enterprise Big Data ...

Mellanox releases Ethernet Switch Application Programing Interface (API) to the community as part of the Open Ethernet initiative ...

Mellanox releases world's first 40 Gigabit Ethernet NIC based on Open Compute Project (OCP) designs ...

Mellanox announces launch of Mellanox Capital ...

Computer models help decode cells that sense light without seeing ...

Heavy metal in the early cosmos ...

Scientists use 'voting' and 'penalties' to overcome errors in quantum optimization ...

2013 International Science and Engineering Visualization Challenge winners announced ...

New IBM virtualization solution to speed Software Defined Networking deployments ...

NEC contributes Network Virtualization to OpenDaylight's Hydrogen release ...

Diamond defect boosts quantum technology ...

Oracle and Pluribus Networks collaborate on OpenStack plug-ins for Software Defined Networking products ...

Solving a 30-year-old problem in high mass star formation ...

IBM named an innovation leader in Big Data in Sub-Saharan Africa, notes Frost & Sullivan ...

Computer models help decode cells that sense light without seeing


Olivucci/BGSU
7 Feb 2014 Columbus - Researchers have found that the melanopsin pigment in the eye is potentially more sensitive to light than its more famous counterpart, rhodopsin, the pigment that allows for night vision. For more than two years, the staff of the Laboratory for Computational Photochemistry and Photobiology (LCPP) at Ohio's Bowling Green State University (BGSU), have been investigating melanopsin, a retina pigment capable of sensing light changes in the environment, informing the nervous system and synchronizing it with the day/night rhythm. Most of the study's complex computations were carried out on powerful supercomputer clusters at the Ohio Supercomputer Center (OSC).

The research recently appeared in theProceedings of the National Academy of Sciences USA, in an article edited by Arieh Warshel, Ph.D., of the University of Southern California. Arieh Warshel and two other chemists received the 2013 Nobel Prize in Chemistry for developing multiscale models for complex chemical systems, the same techniques that were used in conducting the BGSU study, "Comparison of the isomerization mechanisms of human melanopsin and invertebrate and vertebrate rhodopsins".

"The retina of vertebrate eyes, including those of humans, is the most powerful light detector that we know", explained Massimo Olivucci, Ph.D., a research professor of Chemistry and director of LCPP in the Center for Photochemical Sciences at BGSU. "In the human eye, light coming through the lens is projected onto the retina where it forms an image on a mosaic of photoreceptor cells that transmits information from the surrounding environment to the brain's visual cortex. In extremely poor illumination conditions, such as those of a star-studded night or ocean depths, the retina is able to perceive intensities corresponding to only a few photons, which are indivisible units of light. Such extreme sensitivity is due to specialized photoreceptor cells containing a light sensitive pigment called rhodopsin."

For a long time, it was assumed that the human retina contained only photoreceptor cells specialized in dim-light and daylight vision, according to Massimo Olivucci. However, recent studies revealed the existence of a small number of intrinsically photosensitive nervous cells that regulate non-visual light responses. These cells contain a rhodopsin-like protein named melanopsin, which plays a role in the regulation of unconscious visual reflexes and in the synchronization of the body's responses to the dawn/dusk cycle, known as circadian rhythms or the "body clock", through a process known as photo-entrainment.

The fact that the melanopsin density in the vertebrate retina is 10,000 times lower than that of rhodopsin density, and that, with respect to the visual photoreceptors, the melanopsin-containing cells capture a million-fold fewer photons, suggests that melanopsin may be more sensitive than rhodopsin. The comprehension of the mechanism that makes this extreme light sensitivity possible appears to be a prerequisite to the development of new technologies.

Both rhodopsin and melanopsin are proteins containing a derivative of vitamin A, which serves as an "antenna" for photon detection. When a photon is detected, the proteins are set in an activated state, through a photochemical transformation, which ultimately results in a signal being sent to the brain. Thus, at the molecular level, visual sensitivity is the result of a trade-off between two factors: light activation and thermal noise. It is currently thought that light-activation efficiency - i.e., the number of activation events relative to the total number of detected photons - may be related to its underlying speed of chemical transformation. On the other hand, the thermal noise depends on the number of activation events triggered by ambient body heat in the absence of photon detection.

"Understanding the mechanism that determines this seemingly amazing light sensitivity of melanopsin may open up new pathways in studying the evolution of light receptors in vertebrate and, in turn, the molecular basis of diseases, such as "seasonal affecting disorders", Massimo Olivucci stated. "Moreover, it provides a model for developing sub-nanoscale sensors approaching the sensitivity of a single-photon."

For this reason, the LCPP group - working together with Francesca Fanelli, Ph.D., of Italy's Università di Modena e Reggio Emilia - has used the methodology developed by Arieh Warshel and his colleagues to construct computer models of human melanopsin, bovine rhodopsin and squid rhodopsin. The models were constructed by BGSU research assistant Samer Gozem, Ph.D., BGSU visiting graduate student Silvia Rinaldi, who now has completed his doctorate, and visiting research assistant Federico Melaccio, Ph.D. - both visiting from Italy's Università di Siena. The models were used to study the activation of the pigments and show that melanopsin light activation is the fastest, and its thermal activation is the slowest, which was expected for maximum light sensitivity.

The computer models of human melanopsin, and bovine and squid rhodopsins, provide further support for a theory reported by the LCPP group in the September 2012 issue ofScience Magazinewhich explained the correlation between thermal noise and perceived colour, a concept first proposed by the British neuroscientist Horace Barlow in 1957. Horace Barlow suggested the existence of a link between the colour of light perceived by the sensor and its thermal noise and established that the minimum possible thermal noise is achieved when the absorbing light has a wavelength around 470 nanometers, which corresponds to blue light.

"This wavelength and corresponding bluish color matches the wavelength that has been observed and simulated in the LCPP lab", stated Massimo Olivucci. "In fact, our calculations also indicate that a shift from blue to even shorter wavelengths - i.e. indigo and violet - will lead to an inversion of the trend and an increase of thermal noise towards the higher levels seen for a red colour. Therefore, melanopsin may have been selected by biological evolution to stand exactly at the border between two opposite trends to maximize light sensitivity."

The melanopsin research project was funded jointly by the BGSU Center for Photochemical Sciences and the College of Arts & Sciences, and, together with grants from the National Science Foundation and the Human Frontier Science Program, helped create the LCPP.
Source: Ohio Supercomputer Center

Back to Table of contents

Primeur weekly 2014-02-10

The Cloud

European Cloud Testing Environment to be offered free of charge during 2014 ...

IBM opens access to SaaS portfolio to help African Universities with next-generation IT skills ...

IBM and Actifio add powerful new data virtualization solutions to IBM Cloud portfolio ...

Numericable Group teams with IBM's SoftLayer to develop a unique High Performance Cloud offer in France ...

HP Autonomy extends market-leading eDiscovery platform to the Cloud ...

IBM's SoftLayer and DataHotel help Japanese companies expand globally ...

IBM fuels innovation and entrepreneurship in Africa ...

Oracle extends the power of modern HR in the Cloud with updates to Oracle HCM Cloud ...

Desktop Grids

New CONVECTOR project studies mechanical engineering problems ...

EuroFlash

MSc in High Performance Computing organized at Edinburgh Parallel Computing Centre ...

PRACE Preparatory Access passes 3-year cap in bloom ...

EPSRC calls for Quantum Technology Hubs to put UK in super position ...

2nd International Conference on Research Infrastructures to launch Call for Contributions ...

Netherlands joins international Elixir Consortium on biological data ...

USFlash

IBM Brings Watson to Africa ...

SGI and Cognilytics partner to bring advanced analytics to enterprise Big Data ...

Mellanox releases Ethernet Switch Application Programing Interface (API) to the community as part of the Open Ethernet initiative ...

Mellanox releases world's first 40 Gigabit Ethernet NIC based on Open Compute Project (OCP) designs ...

Mellanox announces launch of Mellanox Capital ...

Computer models help decode cells that sense light without seeing ...

Heavy metal in the early cosmos ...

Scientists use 'voting' and 'penalties' to overcome errors in quantum optimization ...

2013 International Science and Engineering Visualization Challenge winners announced ...

New IBM virtualization solution to speed Software Defined Networking deployments ...

NEC contributes Network Virtualization to OpenDaylight's Hydrogen release ...

Diamond defect boosts quantum technology ...

Oracle and Pluribus Networks collaborate on OpenStack plug-ins for Software Defined Networking products ...

Solving a 30-year-old problem in high mass star formation ...

IBM named an innovation leader in Big Data in Sub-Saharan Africa, notes Frost & Sullivan ...