Researchers at the California Institute of Technology (Caltech) have found that this worm has evolved a surprisingly optimistic genetic strategy to cope with these disparate conditions--one that could eventually point the way to new treatments for a host of human diseases caused by parasitic worms.
As reported in a paper published in the February 26 issue of Science Express, Paul W. Sternberg, the Thomas Hunt Morgan Professor of Biology at Caltech and an investigator with the Howard Hughes Medical Institute, along with postdoctoral scholar L. Ryan Baugh, looked at the worms' genetic response to conditions of scarcity and plenty.
In dozens of batches of the worms, consisting of tens of millions of individuals, Baugh, now an assistant professor at Duke University, synchronized hatching, so that all of the animals in each batch emerged from their eggs at the same time.
Some of the hatched worms were allowed to develop under conditions with scarce nutrients, and others with plentiful nutrients. At precise time intervals (3, 6, 9, 12, and 15 hours after hatching), subsets of both populations were killed en masse and ground up. Their messenger RNA--the genetic material that is produced upon the activation of genes and then translated to produce proteins--was harvested and analyzed at Caltech's Jacobs Genetics and Genomics Laboratory, a specialized facility designed to conduct large-scale genetic analyses.
In this way, the researchers measured the expression of every one of the worms' approximately 20,000 genes, to determine how that expression differed depending on food availability.
"We also did an experiment in which we took the starved worms and refed them, and took the fed worms and starved them, to see how rapid their response was to the changing conditions," Sternberg says.
The researchers found that the worms responded far more rapidly to being fed than being starved. Being fed also caused the activation of a far greater number of genes than did starvation. For example, three hours of feeding worm larvae that had previously been starved caused the activation of 381 genes, while starving formerly fed worm larvae for three hours caused the activation of only 56 genes.
In addition, the research revealed that as many genes are involved in the worms' response to nutrition as are involved in their overall development. Many of the genes that play a role in that nutritional response have to do with energy metabolism, and in changing the way the animals utilize and store energy.
"It looks like C. elegans is primed to respond faster to better conditions. It is optimistic," Sternberg says. "These worms live, most of the time, in scarcity. They are facing bad conditions--that is, no food--most of the time. Probably they've evolved to take advantage when times get better for a brief period. They grow and reproduce."
The worms' quick response to food appears to be controlled by a vital cellular protein called RNA Polymerase II (RNA Pol II), which is responsible for transcribing DNA into mRNA. In a separate experiment, Sternberg and his colleagues found that RNA Pol II accumulates on genes that respond rapidly to being fed, but in advance of that feeding.
"We speculate that this polymerase accumulation is part of the way in which they can respond so quickly. It's already engaged, ready to go, ready to send out the message. It's like having Paul Revere on the North Shore, ready to ride, when the food comes," Sternberg says.
"It is kind of interesting in hard economic times to think whether we can learn anything from this organism, in terms of being optimistic or pessimistic. Maybe the take-home message is that sometimes when you are faced with scarcity, you should still be optimistic."
Sternberg speculates that other nematodes, including the parasitic worms that cause elephantiasis in humans, and other lymphatic filarial diseases, may also go through similar transitions in nutrition as they transition from one host (say, a mosquito) to another (a human). Those transitions may be mediated by a similar accumulation of RNA Pol II on particular genes. Identifying those genes could provide potential targets for new types of therapeutic drugs.
Kathy Svitil | EurekAlert!
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction