PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Research suggests how mosquitoes evolved an attraction to human scent

2014-11-12
(Press-News.org) New York, NY - The female mosquitoes that spread dengue and yellow fever didn't always rely on human blood to nourish their eggs. Their ancestors fed on furrier animals in the forest. But then, thousands of years ago, some of these bloodsuckers made a smart switch: They began biting humans and hitchhiked all over the globe, spreading disease in their wake.

"It was a really good evolutionary move," says Leslie B. Vosshall, the Robin Chemers Neustein Professor and head of the Laboratory of Neurogenetics and Behavior at The Rockefeller University, and a Howard Hughes Medical Institute investigator. "We provide the ideal lifestyle for mosquitoes. We always have water around for them to breed in, we are hairless, and we live in large groups."

To understand the evolutionary basis of this attraction, Vosshall and her colleagues examined the genes that drive some mosquitoes to prefer humans. Their findings, published in the November 13 issue of Nature, suggest that human-loving mosquitos are attracted to our scent. "They've acquired a love for human body odor, and that's a key step in specializing on us," she says.

The quest to understand what makes some mosquitoes prefer humans began in Rabai, Kenya. In the 1960s and 1970s, scientists visiting the region observed two distinct populations living just hundreds of meters apart. Black mosquitoes, a subspecies called Aedes aegypti formosus, tended to lay its eggs outdoors and preferred to bite forest animals. Their light-brown cousins, Aedes aegypti aegypti, tended to breed indoors in water jugs and mostly hunted humans. "We think we can get a glimpse of what happened thousands of years ago by looking at this little village in Kenya because the players are still there," Vosshall says.

In 2009, Carolyn McBride, who was a postdoc in Vosshall's laboratory at the time, and her co-investigators travelled to Rabai to see if these two groups still existed. The team used turkey basters to collect larvae from tree holes in the forest and sieved larvae from clay pots and metal cans inside people's homes. Back in the lab in New York they reared the insects and discovered that the observations that researchers had made years earlier seemed to hold true: The insects collected indoors tended to be light brown, and when given the option to bite humans or guinea pigs, they mostly choose humans. Those collected in the forest were black and tended to prefer the laboratory guinea pigs.

To zero in on the genes responsible for the human-loving mosquitoes' preference, the researchers crossbred the mosquitoes, creating thousands of genetically diverse grandchildren. And then they sorted those mosquitoes based on their odor preference and compared the two groups.

"We knew that these mosquitoes had evolved a love for the way we smell," Vosshall says. So she and her colleagues looked specifically for genes that had higher levels of expression in the human-loving insects' antennae. These structures contain proteins called odorant receptors that pick up different scents.

Vosshall and her colleagues found 14 genes strongly linked to liking humans, but one odor receptor gene - Or4 - stood out. "It's very highly expressed in human-preferring mosquitoes," Vosshall says.

The researchers guessed that Or4 must be detecting some aroma in human body odor. To figure out which one, they asked volunteers to wear pantyhose for 24 hours. And then they placed those stinky stockings in a machine designed to separate their scent into the hundreds of individual chemicals that make up body odor. The researchers came up with one match, a chemical called sulcatone that was not found in pantyhose worn by guinea pigs.

Sulcatone is an important odor that gives humans our distinctive scent, but there are likely other odors and other genes that help explain mosquitoes' attraction to humans. In fact, adding sulcatone to the guinea pig odor didn't make guinea pig scent more appealing to human-loving mosquitoes. McBride, now at Princeton University, plans to look for other factors to help explain how mosquitoes transitioned from harmless animal-biting insects into deadly vectors of human disease.

The switch from preferring animals to humans involves a variety of behavior adjustments: Mosquitoes had to become comfortable living around humans, entering their homes, breeding in clean water found in water jugs instead of the muddy water found in tree holes. "There's a whole suite of things that mosquitoes have to change about their lifestyle to live around humans," Vosshall says. "This paper provides the first genetic insight into what happened thousands of years ago when some mosquitoes made this switch."

INFORMATION:

McBride is lead author on the Nature study, and Vosshall is senior author. Their coauthors are: Felix Baier and Sarabeth A. Spitzer in Vosshall's laboratory; Aman B. Omondi and Rickard Ignell with the Swedish University of Agricultural Sciences in Alnarp; and Joel Lutomiah and Rosemary Sang with the Kenya Medical Research Institute in Nairobi.

About The Rockefeller University

Founded by John D. Rockefeller in 1901, The Rockefeller University was this nation's first biomedical research institution. Hallmarks of the university include a research environment that provides scientists with the support they need to do imaginative science and a truly international graduate program that is unmatched for the freedom and resources it provides students to develop their capacities for innovative research. The Rockefeller University Hospital, founded in 1910 as the first center for clinical research in the United States, remains a place where researchers combine laboratory investigations with bedside observations to provide a scientific basis for disease detection, prevention, and treatment. Since the institution's founding, Rockefeller University has been the site of many important scientific breakthroughs. Rockefeller scientists, for example, established that DNA is the chemical basis of heredity, identified the weight-regulating hormone leptin, discovered blood groups, showed that viruses can cause cancer, founded the modern field of cell biology, worked out the structure of antibodies, devised the AIDS "cocktail" drug therapy, and developed methadone maintenance for people addicted to heroin. Throughout Rockefeller's history, 24 scientists associated with the university have received the Nobel Prize in physiology/medicine and chemistry, and 21 scientists associated with the university have been honored with the Albert Lasker Medical Research Award. Eighteen Rockefeller University scientists have received the Canada Gairdner Award, and 20 have garnered the National Medal of Science. Currently, the university's award-winning faculty includes five Nobel laureates, seven Lasker Award winners, 10 Canada Gairdner Award honorees, and three recipients of the National Medal of Science. Thirty-three of the faculty members are elected members of the National Academy of Sciences, and 17 are members of the Institute of Medicine. For more information, go to http://www.rockefeller.edu.



ELSE PRESS RELEASES FROM THIS DATE:

Live longer? Save the planet? Better diet could nail both

Live longer? Save the planet? Better diet could nail both
2014-11-12
As cities and incomes increase around the world, so does consumption of refined sugars, refined fats, oils and resource- and land-intense agricultural products such as beef. A new study led by University of Minnesota ecologist David Tilman shows how a shift away from this trajectory and toward healthier traditional Mediterranean, pescatarian or vegetarian diets could not only boost human lifespan and quality of life, but also slash greenhouse gas emissions and save habitat for endangered species. The study, published in the November 12 online edition of Nature by Tilman ...

Study at SLAC explains atomic action in high-temperature superconductors

Study at SLAC explains atomic action in high-temperature superconductors
2014-11-12
Menlo Park, Calif. -- A study at the Department of Energy's SLAC National Accelerator Laboratory suggests for the first time how scientists might deliberately engineer superconductors that work at higher temperatures. In their report, a team led by SLAC and Stanford University researchers explains why a thin layer of iron selenide superconducts -- carries electricity with 100 percent efficiency -- at much higher temperatures when placed atop another material, which is called STO for its main ingredients strontium, titanium and oxygen. These findings, described today ...

Shaking the topological cocktail of success

2014-11-12
Graphene is the miracle material of the future. Consisting of a single layer of carbon atoms arranged in a honeycomb lattice, the material is extremely stable, flexible, highly conductive and of particular interest for electronic applications. ETH Professor Tilman Esslinger and his group at the Institute for Quantum Electronics investigate artificial graphene; its honeycomb structure consists not of atoms, but rather of light. The researchers align multiple laser beams in such a way that they create standing waves with a hexagonal pattern. This optical lattice is then superimposed ...

Jackson Laboratory researchers discover lung regeneration mechanism

2014-11-12
A research team led by Jackson Laboratory Professors Frank McKeon, Ph.D., and Wa Xian, Ph.D., reports on the role of certain lung stem cells in regenerating lungs damaged by disease. The work, published Nov. 12 in the journal Nature, sheds light on the inner workings of the still-emerging concept of lung regeneration and points to potential therapeutic strategies that harness these lung stem cells. "The idea that the lung can regenerate has been slow to take hold in the biomedical research community," McKeon says, "in part because of the steady decline that is seen ...

Brain protein influences how the brain manages stress; suggests new model of depression

2014-11-12
The brain's ability to effectively deal with stress or to lack that ability and be more susceptible to depression, depends on a single protein type in each person's brain, according to a study conducted at the Icahn School of Medicine at Mount Sinai and published November 12 in the journal Nature. The Mount Sinai study findings challenge the current thinking about depression and the drugs currently used to treat the disorder. "Our findings are distinct from serotonin and other neurotransmitters previously implicated in depression or resilience against it," says the ...

Latest supercomputers enable high-resolution climate models, truer simulation of extreme weather

2014-11-12
Not long ago, it would have taken several years to run a high-resolution simulation on a global climate model. But using some of the most powerful supercomputers now available, Lawrence Berkeley National Laboratory (Berkeley Lab) climate scientist Michael Wehner was able to complete a run in just three months. What he found was that not only were the simulations much closer to actual observations, but the high-resolution models were far better at reproducing intense storms, such as hurricanes and cyclones. The study, "The effect of horizontal resolution on simulation ...

HIV virulence depends on where virus inserts itself in host DNA

HIV virulence depends on where virus inserts itself in host DNA
2014-11-12
The human immunodeficiency virus (HIV) can insert itself at different locations in the DNA of its human host - and this specific integration site determines how quickly the disease progresses, report researchers at KU Leuven's Laboratory for Molecular Virology and Gene Therapy. The study was published online today in the journal Cell Host & Microbe. When HIV enters the bloodstream, virus particles bind to and invade human immune cells. HIV then reprogrammes the hijacked cell to make new HIV particles. The HIV protein integrase plays a key role in this process: it ...

NIDA researchers confirm important brain reward pathway

NIDA researchers confirm important brain reward pathway
2014-11-12
Details of the role of glutamate, the brain's excitatory chemical, in a drug reward pathway have been identified for the first time. This discovery in rodents - published today in Nature Communications - shows that stimulation of glutamate neurons in a specific brain region (the dorsal raphe nucleus) leads to activation of dopamine-containing neurons in the brain's reward circuit (dopamine reward system). Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, motivation, and feelings of pleasure. Glutamate is a neurotransmitter ...

China's old-growth forests vanishing despite government policies, Dartmouth research shows

Chinas old-growth forests vanishing despite government policies, Dartmouth research shows
2014-11-12
HANOVER, N.H. - China's anti-logging, conservation and ecotourism policies are accelerating the loss of old-growth forests in one of the world's most ecologically fragile places, according to studies led by a Dartmouth College scientist. The findings shed new light on the complex interactions between China's development and conservation policies and their impact on the most diverse temperate forests in the world, in "Shangri-La" in northwest Yunnan Province. Shangri-La, until recently an isolated Himalayan hinterland, is now the epicenter of China's struggle to wed sustainable ...

Major class of fracking chemicals no more toxic than common household substances

2014-11-12
The "surfactant" chemicals found in samples of fracking fluid collected in five states were no more toxic than substances commonly found in homes, according to a first-of-its-kind analysis by researchers at the University of Colorado Boulder. Fracking fluid is largely comprised of water and sand, but oil and gas companies also add a variety of other chemicals, including anti-bacterial agents, corrosion inhibitors and surfactants. Surfactants reduce the surface tension between water and oil, allowing for more oil to be extracted from porous rock underground. In a new ...

LAST 30 PRESS RELEASES:

Are lifetimes of big appliances really shrinking?

Pink skies

Monkeys are world’s best yodellers - new research

Key differences between visual- and memory-led Alzheimer’s discovered

% weight loss targets in obesity management – is this the wrong objective?

An app can change how you see yourself at work

NYC speed cameras take six months to change driver behavior, effects vary by neighborhood, new study reveals

New research shows that propaganda is on the rise in China

Even the richest Americans face shorter lifespans than their European counterparts, study finds

Novel genes linked to rare childhood diarrhea

New computer model reveals how Bronze Age Scandinavians could have crossed the sea

Novel point-of-care technology delivers accurate HIV results in minutes

Researchers reveal key brain differences to explain why Ritalin helps improve focus in some more than others

Study finds nearly five-fold increase in hospitalizations for common cause of stroke

Study reveals how alcohol abuse damages cognition

Medicinal cannabis is linked to long-term benefits in health-related quality of life

Microplastics detected in cat placentas and fetuses during early pregnancy

Ancient amphibians as big as alligators died in mass mortality event in Triassic Wyoming

Scientists uncover the first clear evidence of air sacs in the fossilized bones of alvarezsaurian dinosaurs: the "hollow bones" which help modern day birds to fly

Alcohol makes male flies sexy

TB patients globally often incur "catastrophic costs" of up to $11,329 USD, despite many countries offering free treatment, with predominant drivers of cost being hospitalization and loss of income

Study links teen girls’ screen time to sleep disruptions and depression

Scientists unveil starfish-inspired wearable tech for heart monitoring

Footprints reveal prehistoric Scottish lagoons were stomping grounds for giant Jurassic dinosaurs

AI effectively predicts dementia risk in American Indian/Alaska Native elders

First guideline on newborn screening for cystic fibrosis calls for changes in practice to improve outcomes

Existing international law can help secure peace and security in outer space, study shows

Pinning down the process of West Nile virus transmission

UTA-backed research tackles health challenges across ages

In pancreatic cancer, a race against time

[Press-News.org] Research suggests how mosquitoes evolved an attraction to human scent