New Microscope Produces High-Speed Images of Living Cells
A new microscope invented by scientists at the Howard Hughes Medical Institute (HHMI) uses Bessel beam plane illumination microscopy, an imaging method that utilizes a thin sheet of light to peer inside living cells. Th e microscope and the technique used to create it were described in Nature Methods.
Using the microscope, researchers have created high-speed, high-resolution movies that show biological processes such as mitosis. Many microscopy techniques require that cells be killed and fixed in position for imaging, explains Liang Gao, Ph.D., a postdoctoral scientist at HHMI and part of the team that developed the microscope. But by scanning a Bessel beam, a type of nondiffracting light beam studied by physicists in the 1980s, the scientists were able to create a light sheet thin enough to image within single living cells.
“Right now we’re working on ideas on how to make the microscope even better. Our job is to push its capability even further,” Dr. Gao says. The team used two innovative techniques to overcome the problems inherent in imaging living cells. Bessel light beams tend to cause excitation in living cells, a problem the scientists dealt with partly by using structured illumination. In this process, the light from the Bessel beam is turned on and offrapidly, and the excitation to the cell is dampened. They also used two-photon microscopy to weaken the Bessel beam's side lobes, which tend to cause the most excitation to a sample or cell.
The new microscope provides better resolution and is much faster than a confocal microscope; in fact, it's capable of producing nearly 200 images per second, Dr. Gao says.
NCI Calls for Proposals on Nutrigenetics Research
The National Cancer Institute (NCI) is looking for scientifically sound proposals on nutrigenetics research, or studies that provide insight into the interplay between genetics, nutrition, and cancer risk.
While an increasing amount of research points to diet as a modifier of cancer risk, the scientific literature on diet and cancer is marked by inconsistencies, according to the NCI, which issued a Request for Information (RFI) in March that sought feedback from researchers on how to best explore nutrigenetics.
Genetic variants may help explain why some people respond to dietary interventions and others do not, and could serve to predict who may be at risk for cancer because of diet, according to Nancy Emenaker, Ph.D., program director for the nutritional science research group in the Division of Cancer Prevention at NCI. “We’d like to know what genetic polymorphisms may warrant investigation and affect response to dietary interventions,” Dr. Emenaker says.
The NCI received just a handful of responses to its RFI, but they are evaluating each one in order to possibly design a Request for Proposals in nutrigenetics, Dr. Emenaker notes. “Some of the feedback was scientifically sound and very on target, while other responses were not,” she adds.
Dr. Emenaker notes that NCI has received several applications for funding of scientific studies into nutrigenetics and would like to receive more. Yet there are great challenges in designing such studies, she acknowledges. These include zeroing in on the dietary components and genetic variants that together may modify cancer risk, how to show whether a dietary intervention works in different populations, and how to design studies that can be replicated. “One study does not drive a change in clinical practice,” Dr. Emenaker says.
Although the NCI has yet to issue a specific Request for Proposals, interested researchers can contact Dr. Emenaker for more information. She can be reached at firstname.lastname@example.org.
HHS Web Portal to Make Health Indicator Data More Accessible
The U.S. Department of Health and Human Services (HHS) has launched a Web portal meant to be a one-stop source for researchers doing U.S. population-based research on rates of health conditions and health procedures.
The purpose behind it is to liberate the data that exists within the federal system.
—Amy Bernstein, Sc.D.
Since launching in February 2011, the site, called the Health Indicators Warehouse (healthindicators.gov), has received more than 20,000 visitors, according to codirector Amy Bernstein, Sc.D.
“The purpose behind it is to liberate the data that exists within the federal system [and] to get as much data as possible out in a publicly accessible place and to get data to the most users possible,” Dr. Bernstein says. Clinicians who use the site can find standardized local and national statistics about health conditions and procedures, she adds. From the site, health professionals can link to the newest information on evidence-based clinical interventions from the Agency for Healthcare Research and Quality's Guide to Clinical Preventive Services.
In the future, the site may have links to other data sources such as research summary reports that would provide the newest evidence-based research on clinical interventions and their efficacy. For instance, a health professional might be able to learn the most successful means of counseling an obese patient about losing weight, or new information about methods to help chronic substance abusers or those addicted to smoking.
“We’ll be evaluating the functionality of the system to make it more user friendly so that the developers of technology applications can get to the data faster and more easily,” says James Craver, MS, codirector of the Health Indicators Warehouse.
Poor Job Market for New Ph.D.s
Many graduate students aiming to obtain a Ph.D. view their academic training and future postdoctoral research work as a ticket to respect and a generous income. But those starry-eyed aspirations may not refl ect cold hard reality. Unfortunately, many scientists who earn Ph.D.s and complete postdoctoral work fail to find wellpaying, secure faculty positions in the shrinking biomedical research job market.
This problem was highlighted last December when National Institutes of Health (NIH) director Frances Collins, M.D., Ph.D., requested the formation of a work group to investigate the gap between the supply of young investigators and the demand for research jobs. At the time of publication, members for the work group had yet to be announced.
In 1973, 55% of Ph.D.s had tenure track positions, but by 2006 that number declined to under 15%, according to the National Science Foundation. And in 1973, 7% of postdoctoral researchers went on to nontenure track positions, a number that swelled to over 30% in 2006, the last year for which figures are available.
While funding for scientific research has contracted since 2003, it's also true that the academic research system has for many years trained many more scientists than can expect to obtain tenure track faculty positions, critics say.
Just ask Paula Stephan, Ph.D., an economist who studies the scientific labor market. “It's a long-term problem that has its roots in the way scientific labs are staffed,” says Dr. Stephan, professor of economics at Georgia State University's Andrew Young School of Policy Studies. Although the recession and stagnant funding for the NIH has affected the job prospects for postdocs, those aren't the only factors affecting the lack of secure faculty positions for Ph.D.s in the biomedical field, she notes.
“There's incentive for universities to grow their Ph.D. programs because everyone is convinced that it's postdoc programs that keep the research system alive,” Dr. Stephan says. She notes that to many universities, postdoctoral students represent a smart, temporary work force with no long-term financial commitment.
“Hiring postdoctoral researchers reduces the risk to the principal investigators and helps them meet their research goals,” she says. “Some say this kind of research system works wonderfully for everyone except for the postdocs and graduate students.”
A number of graduate schools are aiming to address this problem with master's degree programs that teach students with advanced scientific training the business skills needed for a career outside academia. These programs are in place at 110 universities, according to the Council of Graduate Schools. But they simply cannot make a dent in the job needs of the thousands of postdoctoral researchers in the U.S. More than 25,000 doctorates in the sciences were awarded in 2009 alone, and nearly 75% of these graduates accepted postdoctoral positions, according to the National Science Foundation (NSF).
The job market in the pharmaceutical industry for graduating Ph.D.s has also not seen significant improvement in the past 10 years, largely because of an increasing number of mergers and acquisitions that have kept drug company staffs leaner than expected, according to Dr. Stephan. “It's been discouraging,” she says, pointing to statistics from the NSF showing that about 20% of new Ph.D.s work in industry.