Navigation Links
Study shows how mosquitoes handle the heat of a hot blood meal
Date:4/25/2011

COLUMBUS, Ohio Mosquitoes make proteins to help them handle the stressful spike in body temperature that's prompted by their hot blood meals, a new study has found.

The mosquito's eating pattern is inherently risky: Taking a blood meal involves finding warm-blooded hosts, avoiding detection, penetrating tough skin and evading any host immune response, not to mention the slap of a human hand.

Until now, the stress of the hot blood meal itself has been overlooked, researchers say.

Scientists have determined in female mosquitoes that the insects protect themselves from the stress of the change in body temperature during and after a meal by producing heat shock proteins. These proteins protect the integrity of other proteins and enzymes, in turn helping the mosquitoes digest the blood meal and maintain their ability to produce eggs.

Tests in two other types of mosquitoes and in bed bugs showed that these insects undergo a similar response after a blood meal.

"These heat shock proteins are really important in a lot of stress responses. Our own bodies make these proteins when we have a fever," said David Denlinger, professor of evolution, ecology and organismal biology at Ohio State University and senior author of the study. "It's one of those things that, in retrospect, seems obvious that blood meals might cause a stress like that. But it hadn't been pursued before."

The research appears this week in the online early edition of the Proceedings of the National Academy of Sciences.

Denlinger and colleagues conducted experiments in the Aedes aegypti mosquito, which is a carrier of yellow fever.

The researchers placed sensors on female mosquitoes and observed that upon taking in a blood meal on a chicken, the insects' body temperatures increased from 22 to 32 degrees Celsius (71.6 to 89.6 Fahrenheit) within one minute among the most rapid body temperature increases ever recorded in a cold-blooded animal. After the feeding, their body temperatures decreased to room temperature within a few minutes.

In response to that blood feeding, the mosquitoes' level of Hsp70 heat shock protein 70 increased nearly eightfold within one hour and remained at least twice as high as usual for 12 hours. The increase in these proteins was most pronounced in the midgut area.

Denlinger and colleagues tested potential triggers for this protein increase by injecting the mosquitoes with a saline solution at two temperatures: 37 degrees Celsius (98.6 degrees Fahrenheit) and room temperature. Only the warmer saline generated an increase in Hsp70, suggesting that the elevation in temperature associated with the meal, rather than the subsequent increase in body volume, is what causes the generation of those proteins.

Sometimes, mosquitoes feed on cold-blooded amphibians, which should not cause the same amount of stress. To test that theory, the researchers also gave mosquitoes a feeding opportunity on cooler blood, which failed to generate an increase in heat shock proteins.

And what happens if this protein is not produced? The researchers manipulated the mosquitoes' RNA to figure that out.

When the scientists knocked down expression of the gene that encodes the heat shock protein, the amount of Hsp70 production was reduced by 75 percent. Under those circumstances, mosquitoes still ate a normal blood meal. But blood protein levels remained elevated for a longer period of time, suggesting that digestion of those proteins was impaired. In addition, egg production decreased by 25 percent when the heat shock protein was suppressed.

Heat shock proteins help maintain the three-dimensional integrity of enzymes and proteins when temperatures rise suddenly, and can target damaged proteins and enzymes for elimination, Denlinger said. "We think that in this case, they are important to maintaining the integrity of some critical enzymes and proteins involved in digestive processes. When we knock out those proteins, it impairs digestion a bit and as a result the mosquitoes don't lay as many eggs," he said.

The researchers observed similar body temperature increases and elevations in Hsp70 levels in three other insects: Culex pipiens and Anopheles gambiae, mosquitoes that are carriers of West Nile virus and malaria, respectively, and Cimex lectularius, the bed bug. Though new knowledge about the genetics of these insects, especially the mosquitoes, might someday inform attempts to kill them as a method of disease control, Denlinger said the primary contribution of this research is better understanding of how mosquitoes protect themselves in this novel way.


'/>"/>

Contact: David Denlinger
denlinger.1@osu.edu
614-292-6425
Ohio State University
Source:Eurekalert

Related biology news :

1. Study in roundworm chromosomes may offer new clues to tumor genome development
2. Gulf oil spill similar to Exxon Valdez in initial social and mental impacts, study finds
3. Study of deer mice on Californias Channel Islands provides new information on hantavirus
4. VIMS study: Propeller turbulence may affect marine food webs
5. Reptilian root canal: U of T Mississauga study reveals infection in jaw of ancient fossil
6. Nationwide study finds US meat and poultry is widely contaminated
7. New study finds stronger regulations of in vitro fertilization may save lives
8. Study: Algae could replace 17 percent of US oil imports
9. Scots carbon emissions could be halved in decades, study suggests
10. Alcohol helps the brain remember, says new study
11. Study provides new way to classify E. coli bacteria and test for fecal contamination
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/15/2016)... , April 15, 2016  A new partnership ... more accurate underwriting decisions in a fraction of ... competitively priced and high-value life insurance policies to ... With Force Diagnostics, rapid testing (A1C, ... data readings (blood pressure, weight, pulse, BMI, and ...
(Date:3/31/2016)...   LegacyXChange, Inc. ... LegacyXChange is excited to release its first ... be launched online site for trading 100% guaranteed authentic ... also provide potential shareholders a sense of the value ... industry that is notorious for fraud. The video is ...
(Date:3/22/2016)... 2016 According to ... for Consumer Industry by Type (Image, Motion, Pressure, ... & IT, Entertainment, Home Appliances, & Wearable ... 2022", published by MarketsandMarkets, the market for ... USD 26.76 Billion by 2022, at a ...
Breaking Biology News(10 mins):
(Date:5/26/2016)... , May 26, 2016  Agriculture nutrients are ... Des Moines, Iowa is running their nitrate ... Lake Erie and coastal regions nationwide ... to preventing this widespread issue. NECi Superior ... Upper Peninsula, developed a new, easy to use ...
(Date:5/26/2016)... (PRWEB) , ... May 26, 2016 , ... ... manufacturing company, today announced several positive developments that position the Company for the ... result of the transaction, Craig F. Kinghorn has been appointed Chairman of the ...
(Date:5/25/2016)... ... 2016 , ... Founder of the Fitzmaurice Hand Institute in ... of the hand by the National Board of Physicians and Surgeons, as of ... in his pursuit of providing the most comprehensive, effective treatment for his patients, ...
(Date:5/25/2016)... ... May 25, 2016 , ... Biohaven Pharmaceutical Holding Company Ltd. ... the company’s orphan drug designation request covering BHV-4157 for the treatment of Spinocerebellar ... FDA. , Spinocerebellar ataxia is a rare, debilitating neurodegenerative disorder that is ...
Breaking Biology Technology: