(Press-News.org) DURHAM, N.C. – Chandra Tucker shines a blue light on yeast and mammalian cells in her Duke University lab and the edges of them start to glow. The effect is the result of a light-activated switch from a plant that has been inserted into the cell.
Researchers could use this novel "on-off switch" to control cell growth or death, grow new tissue or deliver doses of medication directly to diseased cells, said Tucker, an assistant research professor in the biology department at Duke.
She and colleagues created the switch by genetically inserting two proteins from a mustard plant, Arabidopsis thaliana, into yeast cells, kidney cells and cultured rodent brain tissue. The two proteins interact under light to provide the control over cell functions.
The switch is similar to one described last year where researchers genetically inserted a different light-receptive plant protein and its interacting protein partner from Arabidopsis into mammalian cells. In response to red light, these proteins interacted to cause mammalian cells to change shape, moving in the direction of the light.
Tucker's switch uses Arabidopsis proteins that respond to blue light. Unlike the red-light activated proteins, which need an added cofactor, a chemical that is required for the light response, the blue-light switch doesn't need any additional chemicals to work because it uses a cofactor that naturally exists in non-plant organisms.
"It's hard to deliver a chemical to a fly or to individual cells. This new approach, with one of the molecules already in the mammalian or yeast cells, makes building a light-controlled switch a lot easier," Tucker said. Her team describes the switch in the Oct. 31 Nature Methods.
To test the switch, the team fused one of the light-sensitive Arabidopsis proteins to a red fluorescent protein and the other to a green fluorescent protein, which was in turn attached to the cell membrane. When the researchers flashed blue light on the cell, the plant proteins interacted, causing the red fluorescent protein to rapidly move to the cell membrane, which then glowed yellow due to the merging of the red and green fluorescing proteins. The team found that this interaction was reversible and could be triggered repeatedly with light exposure.
The switch is one among several that have been designed to give researchers better control of different functions of the cell. The next step in developing the switch will be to make the interacting proteins more effective, Tucker said. The approach is expected to be applicable not only for studies in cultured cells and yeast, but also worms, fruit flies, mice and other model organisms. Eventually this method could allow researchers to test how cells in a tissue affect neighboring cells in a tissue, to guide axon growth in neurons to repair brain tissue, or even to kill cancer cells.
Tucker's new approach will be a "major boon" to those who wish to apply light activation to their own experimental systems, said Klaus Hahn, a pharmacologist at the University of North Carolina at Chapel Hill, whose lab reported on another blue-light responsive protein to control movement of mammalian cells last year.
Hahn said the "elegant work will likely see broad use, in many fields and for applications that will surprise us," and it is already going to be applied to important areas of research, such as control of gene expression.
###
END
Scientists from the UK and Australia have seen the human immune system's assassin – a protein called perforin – in action for the first time. The UK team, funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the Wellcome Trust, is based at Birkbeck College where they used powerful electron microscopes to study the mechanism that perforin uses to punch holes in rogue cells. The research is published today (1800hrs, 31 October) in Nature.
Professor Helen Saibil, who leads the UK team at Birkbeck College, said "Perforin is a powerful bullet in ...
A team of Melbourne and London researchers have shown how a protein called perforin punches holes in, and kills, rogue cells in our bodies. Their discovery of the mechanism of this assassin is published today in the science journal Nature.
"Perforin is our body's weapon of cleansing and death," says project leader Prof James Whisstock from Monash University.
"It breaks into cells that have been hijacked by viruses or turned into cancer cells and allows toxic enzymes in, to destroy the cell from within. Without it our immune system can't destroy these cells. Now we ...
PROVIDENCE, R.I. [Brown University] — Roughly 3.5 billion years ago, the first epoch on Mars ended. The climate on the red planet then shifted dramatically from a relatively warm, wet period to one that was arid and cold. Yet there was at least one outpost that scientists think bucked the trend.
A team led by planetary geologists at Brown University has discovered mounds of a mineral deposited on a volcanic cone less than 3.5 billion years ago that speak of a warm and wet past and may preserve evidence of one of the most recent habitable microenvironments on Mars.
Observations ...
DARIEN, IL – A study in the Nov. 1 issue of the journal SLEEP found that vulnerability to sleep deprivation is influenced by the interaction between waking social activity and individual personality traits.
Results show that extraverts who were exposed to 12 hours of social interaction were more vulnerable to subsequent sleep deprivation than those who were exposed to an identical period of isolated activity. Speed on the Psychomotor Vigilance Task (PVT) for extraverts in the socially enriched group was significantly slower at 4 a.m., 6 a.m. and noon compared with speed ...
London, UK (November 1, 2010) – In April 2010, the US government adopted a new nuclear strategy that depends on the conclusion that the current missile defense systems will reliably protect the continental United States in the extreme circumstances of nuclear-armed combat. Now research in the Bulletin of Atomic Scientists, published by SAGE, shows that these defenses have not been tested against real-world threats and would not be effective in real combat conditions.
The April 2010 strategy relies on assumptions that the current US Ground-Based Missile Defense (GMD) and ...
Protected areas are generally seen as a triumph for the preservation of nature, yet the reality on the ground is more complex.
The world's largest protected areas encompass vast amounts of wilderness but do not extensively overlap the highest priority areas for conservation or include unusually large numbers of birds, amphibians, or mammals, according to an analysis published in the November issue of BioScience. The study, by Lisette Cantú-Salazar and Kevin J. Gaston of the University of Sheffield, United Kingdom, nonetheless describes anecdotal evidence that some very ...
Alexandria, VA — Racial and ethnic disparities among children with frequent ear infections (FEI) significantly influence access to affordable healthcare, according to new research published in the November 2010 issue of Otolaryngology – Head and Neck Surgery.
Ear infections are one of the most common health problems for children, with most kids experiencing at least one by their third birthday. Annual costs in the United States alone are in the billions of dollars.
Despite changes that have occurred in healthcare to help low-income children, such as the Children's ...
VIDEO:
Steven Moss, M.D., a gastroenterologist with Rhode Island Hospital, and his colleagues found that 33 individuals were responsible for 305 cases of medical intervention to remove foreign bodies that were...
Click here for more information.
PROVIDENCE, RI – A new study from Rhode Island Hospital found that 33 individuals were responsible for 305 cases of medical intervention to remove foreign bodies that were intentionally swallowed, resulting in more than $2 million in ...
SEATTLE--Primary-care clinicians know teen depression is common, but they've lacked a reliable screening test for it. Now researchers at the University of Washington (UW), Seattle Children's, and Group Health report the PHQ-9 (Patient Health Questionnaire - 9 item) is a good screening test for major depression in adolescents.
Led by Laura P. Richardson, MD, MPH, the team tested the PHQ-9 as a screening tool for depression in 442 teenage patients, age 13-17, at Group Health. The test is brief, available free of charge, easy to score and understand, and proven to find ...
LAWRENCE, Kan. – A little self-awareness can help people struggling in the world of relationships, says Jeffrey Hall, assistant professor of communication studies at the University of Kansas.
Hall recently completed a study into styles of flirting among dating adults, surveying more than 5,100 people regarding their methods of communicating romantic interest.
"Knowing something about the way you communicate attraction says something about challenges you might have had in your past dating life," Hall said. "Hopefully, this awareness can help people avoid those mistakes ...
