Summaries of some of the most interesting Energy Research projects.
- Radioactive platinum joins the fight against AIDS: Radioactive platinum is attached to the AZT molecule.
- So far and yet so close: An electron microscope meets “cyberspace.”
- Unlocking protein structure: The molecular structure of thyroid is revealed in detail.
- Microemulsions to clean oil spills: Investigating the optimum properties of microemulsions for cleaning up oil spills.
- Why addiction? The biochemistry of addiction is being mapped.
- Genetic quick study: Polymer solutions may speed the DNA separation process.
- Siberian nights cloudy, not as cold: What are the implications of a changing Siberian cloud cover?
Radioactive platinum joins the fight against AIDS
Radioactive platinum has been attached to the AZT molecule as a new weapon against AIDS. AZT (similar to thymidine, a component of DNA) is taken up by infected T-cells in much larger quantities than by uninfected T-cells. Researchers at Oak Ridge National Laboratory, working with Children’s Hospital in Boston, exploited this in developing a strategy to kill cells infected with human immunodeficiency virus and thus deny the cell’s reproductive machinery to the HIV. The researchers attached the radioisotope platinum-195m to the AZT molecule. Pt-195m is highly radiotoxic when confined to a living cell or when the dead cell is engulfed by a macrophage. Researchers hope that using radiolabled AZT to destroy infected T-cells and macrophages will lead to more effective treatment of AIDS.
So far and yet so close
For more than a decade, scientists have traveled to Berkeley to use the unique high voltage electron microscope at Ernest Orlando Lawrence Berkeley National Laboratory. Soon, the Berkeley Lab will take the facility to the user. The three-story-tall microscope (the most powerful in the nation) has not been put on wheels. Rather, the Laboratory has created a set of interactive, online computing tools that will allow scientists to manipulate the instrument, conduct experiments, and view images from their own offices, via the Internet. Objects viewed by an electron microscope rapidly change shape and location, requiring constant adjustment by the operator. The time-lag inherent to Internet connections has made remote operation impossible in the past. The Berkeley team created algorithms that recognize shapes and constantly adjust the microscope. Experimenters at remote locations will be able to “drive” the microscope. They will change magnification, scan the sample, alter its orientation, and trigger a range of experimental conditions.
Unlocking protein structure
Researchers at the University of California at San Francisco were attempting to determine the molecular structure of the thyroid hormone-receptor complex by x-ray crystallography. The crystals diffract x-rays weakly, and the conventional laboratory x-ray source could only resolve structures 3.5 angstroms in diameter or larger. Finer resolution was needed to determine the structure at the molecular level. The researchers took their crystals to the Stanford Synchroton Radiation Laboratory and generated high energy x-rays from the electron storage ring. These x-rays were about ten times stronger than conventional laboratory x-rays and provided resolution down to 2 angstroms, a 40% increase in detail. This allowed the molecular structure to be determined. “Biology is examining larger molecules that all diffract poorly,” Richard Wagner, UCSF researcher, said, “as a result, the SSRL will probably see increased use in the future.”
Microemulsions to clean oil spills
Microemulsions are spherical aggregates of large molecules that make efficient contact with both water and organic solvents. In a predominantly aqueous environment, they coat oil droplets; in a predominantly oily environment, they coat water droplets. The result in both cases is an emulsion: the droplets are so small they don’t settle out or float, they remain suspended. Brookhaven National Laboratory researchers and their collaborators from the Exxon Corporation and the Massachusetts Institute of Technology are studying microemulsions that can be used to clean up oil spills. The researchers are using neutron beams from the High Flux Beam Reactor to investigate the chemistry and physical properties of microemulsions under various temperatures and chemical conditions to determine which would be optimal for cleaning up oil spills. A related application is putting oil buried deep in wells into solution so it may be flushed out.
The biochemistry of addiction is being mapped. Positron emission tomography, the mapping device, is helping researchers to explain the dopamine neurotransmitter mechanism responsible for cocaine addiction. PET provides images of the distribution and movement of positron emitter-labeled radiotracers. Research includes radiotracer development and the study of other forms of substance abuse and their genetic component, cancer, and drug development. The PET program operates a whole-body positron emission tomograph and two cyclotrons. It is dedicated to radionuclide research and the production of short-lived positron emitters for research in the neurosciences. A new high-field (4 Tesla) human MRI facility is nearing completion and will be dedicated to the development of new forms of imaging and research in the neurosciences. Collaborative ties have been formed with universities, medical centers, VA hospitals and the pharmaceutical industry. This research was conducted at Brookhaven National Laboratory by Nora D.Valkow and Joanne S. Fowler.
Siberian nights cloudy, not as cold
Siberian nights are not as cold as they used to be, according to climatic records of the past five decades. This information comes from the world data center in Obninsk, Russia. Dale Kaiser of the Carbon Dioxide Information Analysis Center at Oak Ridge National Laboratory believes clouds are one reason for a decrease in the range of daily temperature fluctuations in central and eastern Siberia. Records show an increase in cloud cover, particularly high cirrus clouds, that is trapping heat over the vast Russian region. The significance, Kaiser explains, is that “Alaskan permafrost has warmed 2 to 4 degrees centigrade in the past 50 to 100 years. Thawing of Siberia’s vast permafrost areas would release large amounts of methane, a very efficient greenhouse gas. While warmer temperatures are in general expected to enhance plant growth, Alaska research shows that warming could also increase moisture losses and pest populations, which could have the opposite effect on boreal forests.” The CDIAC is sponsored by ER’s Global Change Research Program.
Genetic quick study
Researchers seek faster ways to decode all three billion base pairs that encode the 100,000 human genes. At Brookhaven National Laboratory and the State University of New York at Stony Brook, researchers are investigating polymer solutions that may replace the gel currently used in the separation process. They are using the neutron scattering at the High Flux Beam Reactor to study the physical properties of the polymer solutions. The researchers are examining how properties of the polymers relate to their ability to separate DNA fragments. Using the new technology, researchers inject about five microliters of polymer solution into a 50-cm capillary tube for electrophoresis. In addition, automated sequencing techniques are being developed to work with capillary electrophoresis. These techniques should be able to determine the sequence of hundreds of thousands of base pairs per day. A prototype 8-capillary system that analyzes more than 400 bases of sequence from each capillary in less than an hour is being used to develop software for automatically reading out the sequence and to test protocols for preparing samples and replacing the resolving matrix. These efforts are part of the Human Genome Project.