Mosquito scent discovery could change a billion lives

US researchers genetically modify mosquitoes making females less likely to spread diseases like dengue and Zika fever.

Researchers in the United States have genetically modified mosquitoes to make humans less attractive to them - a discovery that could dramatically reduce the spread of mosquito-borne diseases, such as dengue, malaria and Zika fever.

Female mosquitoes have been long known to use an array of sensory information to find people to bite. They can sense exhaled carbon dioxide from as far as 10 metres away, as well as being able to detect body odour, heat and moisture.

But new research, published in the journal Current Biology, has shown an acidic component in human sweat plays a key role in attracting the insect.

"We wanted to understand the genetic basis of how the mosquitoes detect their human hosts," Matthew DeGennaro, a mosquito neurobiology researcher at Florida International University, told Al Jazeera.

Gene identified

The scientists identified a gene - known as Ir8a - expressed in the mosquito's antenna. This gene appears to allow female mosquitoes, the ones that suck blood, to smell lactic acid, a particular acidic vapour in human sweat.

Using advanced CRISPR/Cas9 gene-editing technology, the researchers were able to disrupt that gene, making the female Aedes aegypti mosquitoes significantly less interested in humans.

"Removing the function of Ir8a removes approximately 50 percent of host-seeking activity," said DeGennaro.

The genetically-modified mosquitoes were less likely to detect and bite humans, making them much less likely to spread mosquito-borne illnesses.

For a species such as Aedes aegypti, which lives alongside half of the world's population and spreads diseases that kill millions of people each year, this genetic modification has huge potential health benefits.

"The transmission of diseases like dengue, yellow fever, Zika, and malaria can be blocked if we stop these mosquitoes from biting us," said DeGennaro

Repellent potential

While the release of genetically-modified mosquitoes into the wild to combat the spread of dengue fever has been a controversial practice, this latest research is not only focused on the potential of cross-breeding them with wild populations.

The researchers say their work can also offer a more advanced understanding of how mosquitoes hunt and feed on their human targets and will allow them to develop improved mosquito repellents.

These could include life-saving perfumes or scents that would disrupt mosquitoes' sense of smell and protect people from being bitten.

"Odours that mask the IR8a pathway could enhance the efficacy of current repellents like DEET or picaridin. In this way, our discovery may help make people disappear as potential hosts for mosquitoes," said DeGennaro.

In the same way, the researchers say they may be able to use the discovery to overstimulate parts of the insect's detection system and use the scent to lure them away from our humans and into traps.

The effect is "like getting on an elevator with someone who has put on way too much cologne", Larry Zwiebel, a biologist at Vanderbilt University, told US broadcaster NPR.

In February this year, the World Health Organization warned that an emerging resistance to insecticides could lead to a large increase in malaria cases and mortality.

The effects of climate change, which will make more parts of the world hospitable to mosquitoes and the diseases they spread, are also expected to hamper control efforts.

It's in this context that new and innovative insect control methods like those developed by the Florida researchers are going to become increasingly important.

Researchers were able to disrupt the Ir8a gene, making female mosquitoes significantly less interested in humans [Florida International University/Flickr]

Eating small amounts of red and processed meats may increase risk of early death

A new study out of Loma Linda University Health suggests that eating red and processed meats -- even in small amounts -- may increase the risk of death from all causes, especially cardiovascular disease.

Saeed Mastour Alshahrani, lead author of the study and a doctoral student at Loma Linda University School of Public Health, said the research fills an important gap left by previous studies that looked at relatively higher levels of red meat intake and compared them with low intakes.

"A question about the effect of lower levels of intakes compared to no-meat eating remained unanswered," Alshahrani said. "We wanted to take a closer look at the association of low intakes of red and processed meat with all-cause, cardiovascular diseases, and cancer mortality compared to those who didn't eat meat at all."

This study, "Red and Processed Meat and Mortality in a Low Meat Intake Population" is part of the Adventist Health Study-2 (AHS-2), a prospective cohort study of approximately 96,000 Seventh-day Adventist men and women in the United States and Canada. The principal investigator of AHS-2 is Gary E. Fraser, MD, PhD, professor of medicine and epidemiology at Loma Linda University Health.

Adventists are a unique population -- approximately 50 percent are vegetarians, and those who consume meat do so at low levels. This allowed researchers to investigate the effect of low levels of red and processed meat intake compared to zero-intake in a large setting such as the Adventist Health Study.

The study evaluated the deaths of over 7,900 individuals over an 11-year period. Diet was assessed by a validated quantitative food frequency questionnaire and mortality outcome data were obtained from the National Death Index. Of those individuals who consumed meat, 90 percent of them only ate about two ounces or less of red meat per day.

Nearly 2,600 of the reported deaths were due to cardiovascular disease, and over 1,800 were cancer deaths. Processed meat -- modified to improve flavor through curing, smoking, or salting (such as ham and salami) -- alone was not significantly associated with risk of mortality possibly due to a very small proportion of the population who consume such meat. However, the total intake of red and processed meat was associated with relatively higher risks of total and cardiovascular disease deaths.

Michael Orlich, MD, PhD, co-director of AHS-2 and co-author of the present study, said these new findings support a significant body of research that affirms the potential ill health effects of red and processed meats.

"Our findings give additional weight to the evidence already suggesting that eating red and processed meat may negatively impact health and lifespan," Orlich said.

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Aspirin to fight an expensive global killer infection

Research led by the Centenary Institute in Sydney has found a brand new target for treating drug-resistant tuberculosis; our scientists have uncovered that the tuberculosis bacterium hijacks platelets from the body's blood clotting system to weaken our immune systems.

Tuberculosis is far from eradicated around the world and still infects more than 1,400 people per year in Australia. Antibiotic resistant tuberculosis is particularly deadly and expensive to treat, costing up to $250,000 to treat a single case in Australia. Scientists at the Centenary Institute have been working on new ways to treat tuberculosis by increasing the effectiveness of the immune system.

Using the zebrafish model of tuberculosis, the researchers used fluorescent microscopy to observe the build-up of clots and activation of platelets around sites of infection. Senior author and head of the Centenary's Immune-Vascular Interactions laboratory, Dr Stefan Oehlers, says "the zebrafish gives us literal insight into disease processes by watching cells interacting in real time."

Following their hunch that these platelets were being tricked by the infection into getting in the way of the body's immune system, the researchers treated infections with anti-platelet drugs, including widely available aspirin, and were able to prevent hijacking and allow the body to control infection better.

Dr Elinor Hortle, lead author of the paper published in The Journal of Infectious Diseases, and Research Officer in Centenary's Immune-Vascular Interactions laboratory says "This is the first time that platelets have been found to worsen tuberculosis in an animal model. It opens up the possibility that anti-platelet drugs could be used to help the immune system fight off drug resistant TB."

There are over 1.2 million Australians living with latent tuberculosis, a non-infectious form of TB that puts them at risk of developing the active disease. "Our study provides more crucial evidence that widely available aspirin could be used to treat patients with severe tuberculosis infection and save lives," says Dr Hortle.

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Proofs of parallel evolution between cognition, tool development, and social complexity

A study analyses the selective attention processes that determine how we explore and interact with our environment.

Researchers examined the visual response of 113 individuals when observing prehistoric ceramics belonging to different styles and societies. The ceramics analysed cover 4,000 years (from 4000 B.C. to the change of era) of Galician prehistory (north-west Iberia), and are representative of ceramic styles, such as bell-beaker pottery, found throughout Europe. The results indicate that the visual behaviour follows the same evolutionary trends as those that drive the evolution of the complex societies that built these archaeological materialities.

"We hypothesised that culture and social life influence cognition in a highly stereotyped fashion. Eye movements are the most objective proof of a parallel evolution between the cognitive process, material development and changes in social complexity," explains CSIC researcher Felipe Criado-Boado, from the Institute of Heritage Sciences, in Santiago de Compostela. This study is part of the field of neuroarchaeology, a new scientific field that combines neuroscience with human palaeontology, archaeology, and other social and human sciences.

"The visual prominence of each ceramic style produces a distinct visual response. Prehistoric ceramics comprise an important part of the material world that surrounded the individuals of that time. This is why an analysis of this kind is not only feasible, but also provides very significant results," adds Criado-Boado.

Luis M. Martínez, a researcher from the Institute of Neurosciences, in Alicante, explains that, "in our brain there are neural circuits, or maps, that represent our personal and peripersonal space. These circuits determine the way in which we relate socially, and also with the world around us. With experiments of this kind, we are demonstrating that these representations are modified by the use and making of tools and other cultural artefacts; what we are discovering is that they are quickly incorporated into these neural maps, becoming part of our body schema as if they were an extension of it. These experiments unequivocally demonstrate that there is a very close interaction between cultural changes and brain plasticity, which provides a new perspective on how the brain governs for the transmission of cultural values, beliefs and customs."

The results of this research indicate that the human visual system actively internalises the object it observes, which would demonstrate that there is a perceptual engagement between the observers and the material structures in their environment. "This is why perception cannot be separated from form. Seen from this perspective, it could be proposed that the shape of objects (pottery, in this case) and the pattern of visual exploration they produce have changed over history, and are connected with behaviour in the same way as they are with the social realm, including social complexity," says Criado-Boado.

Another of the conclusions of this study is that technology is an important factor in the mental aspects of human life. This offers a new perspective that helps to explain the processes of innovation and technological change that take place in all historical periods, including the present day. "It is believed that by 2020 there will be 100 billion sensors around the world capturing information of all kinds and processing it digitally, all connected to each other and functioning like an enormous human mind. If this prediction is fulfilled, research in the field of cognitive processes and material culture throughout history may be useful for the future, since it can show how humans rely on images that symmetrically help them to shape a collective consciousness of the world," concludes the researcher.

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Low-dose aspirin does not seem to improve survival after prostate cancer diagnosis

Low-dose aspirin use does not seem to reduce the overall risk for prostate cancer death at the population level. However, results for extended exposure periods suggest that low-dose aspirin might be inversely associated with prostate cancer mortality after 5 years from cancer diagnosis. Findings from a nationwide cohort study are published in Annals of Internal Medicine.

Recent studies suggest that aspirin use may improve survival in patients with prostate cancer, but study results are inconclusive.

Researchers from the Danish Cancer Society Research Center, Aarhus University Hospital, Copenhagen University Hospital, and University of Southern Denmark used nationwide registries in Denmark to assess the association between postdiagnosis use of low-dose aspirin and prostate cancer mortality. Their analysis did not find convincing evidence of an overall protective effect of low-dose aspirin for men with prostate cancer. However, they did find a reduced risk for prostate cancer mortality with low-dose aspirin use among patients with low Gleason scores, meaning that their prostate cancer was unlikely to progress, and among those who took low-dose aspirin for an extended period of time.

The authors of an accompanying editorial from Tampere University and Tampere University Hospital in Finland speculate that improved prostate cancer-specific survival among aspirin users with low Gleason scores might be explained by inaccurate tumor grading occurring less frequently in aspirin users than nonusers. Aspirin is an anti-inflammatory drug that lowers serum prostate-specific antigen levels; however, whether this leads to accurate determination of tumor aggressiveness in aspirin users remains to be determined in further studies, according to the authors. They suggest that future research evaluate aspirin exposures longer than those studied to date and investigate the effects of aspirin exposure on disease classification.

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Combining morning exercise with short walking breaks helps control blood pressure

Thirty minutes of morning exercise lowers blood pressure for the rest of the day among older men and women who are overweight or obese. And women who take brief, frequent breaks from sitting throughout the day can enhance the blood pressure benefits of morning exercise even more, according to new research published in the American Heart Association's journal Hypertension.

In a study of men and women, age 55 to 80, all of whom were overweight or obese, researchers wanted to find out whether the beneficial effect of morning exercise on blood pressure was negated by long periods of sitting throughout the rest of the day. They also wanted to learn whether the benefit of morning exercise would be enhanced by taking frequent, short breaks from sitting.

"Traditionally, the health effects of exercise and sedentary behavior have been studied separately. We conducted this study because we wanted to know whether there is a combined effect of these behaviors on blood pressure," said Michael Wheeler, B.Sc., lead author of the study who is a Ph.D. candidate at the University of Western Australia in Perth and works at the Baker Heart and Diabetes Institute in Melbourne, Australia.

To conduct the study, the researchers had 67 participants (35 of whom were women) take part in three different scenarios, in a random order, separated by at least 6 days:

uninterrupted sitting for 8 hours; one hour of sitting prior to 30 minutes of exercise, followed by 6.5 hours of prolonged sitting (exercise consisted of walking on a treadmill at moderate intensity); and one hour of sitting prior to 30 minutes of exercise, followed by sitting which was interrupted every 30 minutes with 3 minutes of light intensity walking for 6.5 hours. The study was conducted in a controlled laboratory environment, and the participants ate the same standardized meals the night before and during the study. Blood pressure and adrenaline levels were measured repeatedly during each 8-hour condition.

The researchers found that average blood pressure, especially systolic blood pressure, was reduced among both men and women who took part in morning exercise, compared to when they did not exercise. There was further benefit -- a significant reduction in average systolic blood pressure -- for women when they combined morning exercise with frequent breaks from sitting throughout the day. For men, there was no additional blood pressure benefit to taking frequent breaks from sitting.

Systolic blood pressure is the first of two numbers when blood pressure is taken. It measures pressure in blood vessels when your heart beats. Diastolic blood pressure is the second number, which measures pressure between beats. Wheeler says that over age 50, higher systolic blood pressure is more predictive of cardiovascular events than diastolic blood pressure.

The American Heart Association and American College of Cardiology hypertension guidelines define high blood pressure as 130/80 and above.

"For both men and women, the magnitude of reduction in average systolic blood pressure following exercise and breaks in sitting, approached what might be expected from antihypertensive medication in this population to reduce the risk of death from heart disease and stroke. However, this reduction was greater for women." said Wheeler.

The researchers do not know why there was a gender difference, but think it may be a combination of factors, including varying adrenaline responses to exercise and the fact that all women in the study were post-menopausal -- a time when women are at increased risk for cardiovascular disease. Breaks in sitting have been shown in other studies to have a greater beneficial effect on blood pressure among groups with higher risk of cardiovascular disease, according to Wheeler.

The researchers conclude that the benefits of exercise on lowering blood pressure can be enhanced by avoiding prolonged periods of sitting and add that future studies should specifically test for gender differences in blood pressure with breaks in sitting alone.

"Having the study participants begin with exercise was intentional," according to Dr. Wheeler, "because we wanted to focus on the novel aspect of combining exercise with breaks in sitting. However, it means that we cannot say for sure that breaks in sitting alone had no blood pressure lowering effect in men, as any effect could have been masked by the preceding effect of exercise."

Future studies would be needed to see if the same benefits would apply to younger people and those who are not overweight. But, according to Wheeler, "As the proportion of those who are overweight with higher blood pressure increases with age, adopting a strategy of combining exercise with breaks in sitting may be important to control and prevent the development of high blood pressure."

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Keep calm and don't carry on when parenting teens

Researchers look at how mothers and fathers control themselves (and their rising anger) in difficult interactions with their teenagers.

The field of adolescent psychology is increasingly focused on parents, with researchers asking how mothers and fathers control themselves (and their rising anger) in difficult interactions with their children. As anyone who has raised a teenager knows, parental goals often don't exactly align with those of the child. Sometimes, not even close.

"Discipline issues usually peak during toddlerhood and then again during adolescence, because both periods are really marked by exploration and figuring out who you are, and by becoming more independent," says Melissa Sturge-Apple, a professor of psychology and dean of graduate studies in Arts, Sciences & Engineering at the University of Rochester.

Yet the developmental changes during puberty and the transition to adolescence mean that parents necessarily need to adjust their parenting behaviors, she adds. Part of that adjustment is parents' ability to think on their feet and navigate conflicts with flexibility as their teens strive for more autonomy and greater input in the decision-making processes. Sturge-Apple is the lead author of a recent study about mothers' and fathers' capacity for self-regulation as well as hostile parenting during their child's early adolescence. The study is published in the journal Development and Psychopathology.

The research was sparked by an obvious deficit: more than 99 percent of parent regulation studies have focused exclusively on mothers. In this study, Sturge-Apple and her colleagues -- Patrick Davies, professor of psychology at Rochester; Zhi Li, a postdoctoral fellow at the University's Mt. Hope Family Center; Meredith Martin '14 (PhD), now an assistant professor of educational psychology at the University of Nebraska; and Rochester psychology graduate student Hannah Jones -- looked at how mothers and fathers regulated their stress in response to conflict with their adolescent children. They then examined how the stress response affected their discipline of the child. The researchers measured parents' physiological regulation using RMSSD, a widely used measure to assess heart rate variability. The laboratory-based assessments were spaced roughly one year apart.

Dads are more likely than moms to think that their teen was being intentionally difficult, or "just trying to push buttons."

The researchers found that those parents -- both mothers and fathers -- who were less capable of dampening down their anger, as measured by RMSSD, were more likely to resort, over time, to the use of harsh, punitive discipline and hostile conflict behavior vis-à-vis their teenager.

The scientists also measured parents' set-shifting capacity -- that is, the parents' ability to be flexible and to consider alternative factors, such as their child's age and development.

"Set shifting is important because it allows parents to alter flexibly and deliberately their approaches to handling the changeable behaviors of their children in ways that help them to resolve their disagreements," says Davies.

On average, fathers were not as good as mothers at set shifting and were less able to control their physiological anger response. As a result, they were more likely to think that their teen was intentionally difficult, or "just trying to push buttons," which in turn guided their decisions about discipline.

However, the researchers found that those fathers who were better at set shifting than others were also better able to counteract difficulties in physiological regulation. These episodes of physiological dysregulation, the team discovered, predicted over time an increase in parents' angry responses -- and that essentially, set shifting offsets this angry response tendency.

"As we learn more, these findings may have important implications for building and refining parenting programs," says Davies. "For example, there are exercises that help increase physiological regulation in ways that may ultimately reduce hostile parenting behaviors for mothers and fathers."

There's an irony in past research studies' almost exclusive focus on mothers.

"Dads are typically the enforcer in the family and this role may be difficult to override," says Sturge-Apple. "Thus, the ability to be flexible in responses may help dads, more than moms, adjust to the changes of adolescence."

The research, which included 193 fathers, mothers, and their young teenagers (aged 12 to 14), was conducted at the University's Mt. Hope Family Center, which recently garnered an unrelated multi-million-dollar grant to establish a national center to study child abuse and prevention.

The research for this study was funded by a grant from the National Institute of Child Health and Human Development.

Climate change will even change the color of the oceans, study says

(CNN)The ocean will not look the same color in the future. It won't turn pink or anything radically different; the change will be more apparent through optic sensors than though the human eye. But it serves as an early warning sign that global warming is significantly altering the planet's ecosystems, according to a new study.

Essentially, climate change will make the blues of the ocean bluer and the greens greener. Scientists figured this out by creating a global model that simulates the growth of a tiny creature that lives in the oceans and affects the color we see. Their research was published Monday in the journal Nature Communications.

The ocean looks blue or green to us because of a combination of how sunlight interacts with water molecules and with whatever else lives in that water.
The molecules in water absorb all but the blue part of the spectrum of sunlight, and the water reflects that blue color back. That's the color we see.
The water looks greener when it has more phytoplankton, tiny, microscopic organisms that, like plants, can use chlorophyll to capture mostly the blue portions of the spectrum of sunlight. They then use photosynthesis to create the chemical energy they need to live. When there are more of these creatures in the water absorbing sunlight, they make the water look greener. Conversely, if there are fewer phytoplankton, the water looks bluer.
The creatures' growth is dependent on how much sunlight, carbon dioxide and nutrients are around. Climate change is altering the ocean currents, meaning there will be fewer nutrients for phytoplankton to feed on in some areas, so there will be a decline in their number in those regions.
Since the 1990s, satellites have taken regular measurements of how much chlorophyll is in the ocean. Those levels can change because of weather events or because of climate change. But using those images to look at reflected light alone, the researchers in the new study could distinguish what is specifically due to climate change. And they noticed that there will be a significant shift in the color of the oceans much earlier than was previously predicted, just looking at chlorophyll changes.
The study predicts that the blues will intensify, most likely in subtropical regions where phytoplankton will decrease. These are areas near the equator like Bermuda and the Bahamas that are already quite low in phytoplankton.
Regions where there are a lot of nutrients, like in the Southern Ocean or parts of the North Atlantic, will see even faster-growing phytoplankton because those waters are warming with climate change. Those waters will look greener.
Climate change will bring a color change to half of the world's oceans by the end of the 21st century, the study says. That's bad for climate change on several levels: For one, phytoplankton remove about as much carbon dioxide from the air as plants and help regulate our climate, research shows. They are also key to other animals' survival.
"The change is not a good thing, since it will definitely impact the rest of the food web," said study co-author Stephanie Dutkiewicz, a principal research scientist in MIT's Department of Earth, Atmospheric, and Planetary Sciences. "Phytoplankton are at the base, and if the base changes, it endangers everything else along the food web, going far enough to the polar bears or tuna or just about anything that you want to eat or love to see in pictures."
 
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