In the study, Knockout Mice: Is it Just Genetics? Effects of Enriched Housing on Fibulin-4+/- Mice, lead researcher Ann Baldwin, PhD, suggests that environmental factors may play a large part in research findings that investigators assume are due simply to genetic differences. Further, the study research indicates that appropriate environments may counteract the effects of some genetic deficiencies.
The “knockout” technique is used widely by researchers to aid in understanding physiological functions at the cellular and molecular level. Essentially, it eliminates one or both copies of a gene that produces a specific protein or enzyme.
Dr. Baldwin, a professor of physiology and psychology at the UA College of Medicine, developed a study focusing on mice with only one copy of a gene that encodes for an extracellular matrix protein, fibulin-4. The extracellular matrix, often referred to as connective tissue, supports tissue cells. Fibulin-4 is localized in the aortic media and is essential for maintaining arterial integrity. Dr. Baldwin wanted to determine whether these mice, known as heterozygous fibulin-4 knockout mice, showed arterial defects on a microscopic scale, although outwardly they appeared to be normal.
Using high-powered electron microscopy, she found small areas of disorganized tissue, referred to as “gaps,” in the aortas of the heterozygous fibulin-4 knockout mice. The number of gaps found in the knockout mice was approximately 100 times greater than those found in the control, or wild-type, mice.
After preliminary experiments were performed, a second purpose for the study developed, and the researchers set about investigating a hypothesis that the pathologies they observed would be ameliorated by enriched housing conditions.
In the initial experiments, the test mice were housed four-per-cage in standard cages, measuring 26 cm long x 16 cm wide x 12 cm high and containing only bedding. To investigate the effect of enriched housing conditions, the research team repeated the experiments with test animals housed two-per-cage in cages measuring 33 cm long x 25 cm wide x 25 cm high. The larger cages were equipped with a shelf, ladder, exercise wheel and plastic tube.
Observed at night on specific occasions during the testing period, the animals housed in the larger cages spent approximately 40 percent of the observation time exercising in the wheel, while mice housed in the standard cages remained relatively stationary.
Significantly, the mice housed in the standard cages were heavier than those in the larger cages – about twice the weight at the same age – and they showed large quantities of adipose, or fat, tissue around the aorta.
The mice in the larger cages showed virtually no fat around the aorta. They also showed far fewer regions of disorganized tissue in the aorta than those housed in standard cages.
The evidence suggests that even though the knockout mice were genetically predisposed to arterial damage, simply housing them in an enriched environment, where they could perform their normal functions, reduced the number of gaps occurring in the aorta.
Dr. Baldwin explains that one important implication is that housing conditions can affect the differences between wild-type and knockout strains. Thus, research findings that are assumed to be due simply to genetic differences might be interpreted incorrectly; environmental factors may play an important role.
Secondly, as this study indicates, appropriate environments may counteract the effects of some genetic deficiencies. For example, mice given the opportunity to exercise fared better than their counterparts in standard cages.
Knockout Mice: Is it Just Genetics? Effects of Enriched Housing on Fibulin-4+/- Mice, is supported by the National Center for Research Resources and the National Center for Complementary and Alternative Medicine. The full text appears in the Wednesday, Feb. 21, edition of PLoS ONE, the international, peer-reviewed, open-access, online publication from the Public Library of Science (PLoS).
Dr. Baldwin’s research team includes Lihua Marmorstein, PhD, assistant professor of the Department of Ophthalmology and Vision Science at The University of Arizona College of Medicine; Elizabeth Cudilo, UA medical student; and Hamda Al Naemi, PhD, head of the Department of Physiology, University of Qatar.
Citation: Cudilo E, Al Naemi H, Marmorstein L, Baldwin AL (2007) Knockout Mice: Is It Just Genetics? Effect of Enriched Housing on Fibulin-4+/2 Mice. PLoS ONE 2(2): e229. doi:10.1371/journal.pone.0000229
International team discovers novel Alzheimer's disease risk gene among Icelanders
24.10.2016 | Baylor College of Medicine
New bacteria groups, and stunning diversity, discovered underground
24.10.2016 | DOE/Lawrence Berkeley National Laboratory
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Power and Electrical Engineering
24.10.2016 | Life Sciences
24.10.2016 | Life Sciences