These so-called “heat-shock proteins” ensure that the insects will be back to bug us come spring.
A study of flesh flies and a handful of other insects suggests that they have an arsenal of protective heat-shock proteins that are turned on almost as soon as the temperature dips. Until this new study, researchers knew of only two such proteins that were activated in flesh flies during cooler weather.
“Insects need heat-shock proteins in order to survive,” said David Denlinger, the study's lead author and a professor of entomology at Ohio State University. “Without these proteins, insects can't bear the cold and will ultimately die.”
Denlinger and his colleagues found nearly a dozen additional heat-shock proteins that are activated during diapause, a hibernation-like state that insects enter when temperatures drop. Insects can stay in this state of arrested development for several months.
“We certainly didn't expect to find that many proteins active during diapause,” Denlinger said. The researchers report their findings in the current online early edition of the Proceedings of the National Academy of Sciences.
Insects and other animals, including humans, produce heat-shock proteins in response to extremely high temperatures. The proteins are so named because they were initially discovered in fruit flies that were exposed to high heat. Humans make these proteins when we run a high fever.
"But insects make these very same stress proteins during times of low temperature as well as during exposure to high levels of toxic chemicals, dehydration and even desiccation," Denlinger said.
He and his colleagues first figured out how many genes were turned on only during the flesh fly's dormant state. The researchers extracted and compared RNA from both dormant and non-dormant fly pupae – the developmental stage between larva and adulthood. They used a laboratory technique that let them separate out genes that were turned on only in the flies in this dormant state.
The researchers found 11 previously undiscovered genes that turn on heat-shock proteins during diapause. Until this study, they had only known of two such proteins.
Denlinger and his team also examined the expression of one of those previously discovered heat-shock proteins, Hsp70, in five additional insect species that aren't related to the flesh fly. Each insect is a fairly common agricultural pest: the gypsy moth, the European corn borer, the walnut husk maggot, the apple maggot and the tobacco hornworm. Collectively, these species cause millions of dollars of damage annually.
Hsp70 was active while all of the insects were in diapause.
When Denlinger's team knocked out the Hsp70 gene that makes the heat-shock protein, the insects were unable to survive at a low temperature (in this case, insects were exposed to -15°C, or 5°F.)
“This underscores the essential role of this gene for winter survival, suggesting that this particular heat-shock protein is a major contributor to cold tolerance in insects,” Denlinger said. “It's highly likely that the other heat-shock proteins we found during diapause in the flesh fly are also important to an insect's ability to endure months of cold temperatures.”
Denlinger has no plans to develop a method to get rid of heat-shock proteins in insect pests, but he says that it is important to understand how insects survive through the winter.
“There may be steps we can take to disrupt the diapause process and make an insect vulnerable to low temperatures,” Denlinger said. “At this point, the findings broaden our palette of players that contribute to cold tolerance in insects.”
He said the next step is to figure out the unique functions of each heat-shock protein.
“We assume it's not simply redundancy in the system, but that each protein makes a unique contribution somehow,” Denlinger said. “This protective mechanism is much more complex than we envisioned.”
Denlinger conducted the study with colleagues from Ohio State; the U.S. Department of Agriculture's Agricultural Research Station in Fargo, N.D.; the Harvard School of Public Health; and Liverpool University in the United Kingdom.
Funding for the work came from a USDA-National Research Initiative Grant, the National Science Foundation and the National Institutes of Health.
David Denlinger | EurekAlert!
Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz
Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
29.05.2017 | Physics and Astronomy
29.05.2017 | Physics and Astronomy
29.05.2017 | Earth Sciences