Category: Science News

{With honeybee colony health wavering and researchers trying to find technological ways of pollinating plants in the future, a new Georgia Tech study has looked at how the insects do their job and manage to stay clean.}

According to the study, a honeybee can carry up to 30 percent of its body weight in pollen because of the strategic spacing of its nearly three million hairs. The hairs cover the insect’s eyes and entire body in various densities that allow efficient cleaning and transport.

The research found that the gap between each eye hair is approximately the same size as a grain of dandelion pollen, which is typically collected by bees. This keeps the pollen suspended above the eye and allows the forelegs to comb through and collect the particles. The legs are much hairier and the hair is very densely packed — five times denser than the hair on the eyes. This helps the legs collect as much pollen as possible with each swipe. Once the forelegs are sufficiently scrubbed and cleaned by the other legs and the mouth, they return to the eyes and continue the process until the eyes are free of pollen.

The Georgia Tech team tethered bees and used high speed cameras to create the first quantified study of the honeybee cleaning process. They watched as the insects were able to remove up to 15,000 particles from their bodies in three minutes.

“Without these hairs and their specialized spacing, it would be almost impossible for a honeybee to stay clean,” said Guillermo Amador, who led the study while pursuing his doctoral degree at Georgia Tech in mechanical engineering.

This was evident when Amador and the team created a robotic honeybee leg to swipe pollen-covered eyes. When they covered the leg with wax, the smooth, hairless leg gathered four times less pollen.

The high-speed videos also revealed something else.

“Bees have a preprogrammed cleaning routine that doesn’t vary,” said Marguerite Matherne, a Ph.D. student in the George W. Woodruff School of Mechanical Engineering. “Even if they’re not very dirty in the first place, bees always swipe their eyes a dozen times, six times per leg. The first swipe is the most efficient, and they never have to brush the same area of the eye twice.”

The research also found that pollenkitt, the sticky, viscous fluid found on the surface of pollen grains, is essential. When the fluid was removed from pollen during experiments, bees accumulated half as much.

“If we can start learning from natural pollinators, maybe we can create artificial pollinators to take stress off of bees,” said David Hu, a professor in the Woodruff School of Mechanical Engineering and School of Biological Sciences. “Our findings may also be used to create mechanical designs that help keep micro and nanostructured surfaces clean.”

The study, “Honeybee hairs and pollenkitt are essential for pollen capture and removal,” is published in the journal Bioinspiration and Biomimetics.

Source:Science Daily

{When we are around four years old we suddenly start to understand that other people think and that their view of the world is often different from our own. Researchers in Leiden and Leipzig have explored how that works. Publication in Nature Communications on 21 March.}

At around the age of four we suddenly do what three-year-olds are unable to do: put ourselves in someone else’s shoes. Researchers at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and at Leiden University have shown how this enormous developmental step occurs: a critical fibre connection in the brain matures. Senior researcher and Leiden developmental psychologist Nikolaus Steinbeis, co-author of the article, took part in the research. Lead author, PhD candidate Charlotte Grosse-Wiesmann, worked under his supervision.

{{Little Maxi}}

If you tell a 3-year-old child the following story of little Maxi, they will most probably not understand: Maxi puts his chocolate on the kitchen table, then goes to play outside. While he is gone, his mother puts the chocolate in the cupboard. Where will Maxi look for his chocolate whenhe comes back? A 3-year-old child will not understand why Maxi would be surprised not to find the chocolate on the table where he left it. It is only by the age of 4 years that a child will correctly predict that Maxi will look for his chocolate where he left it and not in the cupboard where it is now.

{{Theory of Mind}}

The researchers observed something similar when they showed a 3-year-old child a chocolate box that contained pencils instead of chocolates. When the child was asked what another child would expect to be in the box, they answered “pencils,” although the other child would not know this. Only a year later, around the age of four years, however, will they understand that the other child had hoped for chocolates. Thus, there is a crucial developmental breakthrough between three and four years: this is when we start to attribute thoughts and beliefs to others and to understand that their beliefs can be different from ours. Before that age, thoughts don’t seem to exist independently of what we see and know about the world. That is, this is when we develop a Theory of Mind.

{{Independent development}}

The researchers have now discovered what is behind this breakthrough. The maturation of fibres of a brain structure called the arcuate fascicle between the ages of three and four years establishes a connection between two critical brain regions: a region at the back of the temporal lobe that supports adult thinking about others and their thoughts, and a region in the frontal lobe that is involved in keeping things at different levels of abstraction and, therefore, helps us to understand what the real world is and what the thoughts of others are. Only when these two brain regions are connected through the arcuate fascicle can children start to understand what other people think. This is what allows us to predict where Maxi will look for his chocolate. Interestingly, this new connection in the brain supports this ability independently of other cognitive abilities, such as intelligence, language ability or impulse control.

Source:Science Daily

{Delaying school start times in the UK is unlikely to reduce sleep deprivation in teenagers, research from the University of Surrey and Harvard Medical School has found. The research, conducted in collaboration between mathematicians and sleep scientists, predicts that turning down the lights in the evening would be much more effective at tackling sleep deprivation.}

Teenagers like to sleep late and struggle to get up in time to go to school. The commonly accepted explanation for this is that adolescents’ biological brain clocks are delayed. It has been suggested that to remedy this, school start times should be delayed for older teenagers so that they are again in tune with their biological clock.

The study, which is published today in Scientific Reports, used a mathematical model that takes into account whether people are naturally more of a morning or evening person, the impact of natural and artificial light on the body clock and the typical time of an alarm clock, to predict the effects of delaying school start times.

The mathematical model showed that delaying school start times in the UK would not help reduce sleep deprivation. Just as when clocks go back in the autumn, most teenagers’ body clocks would drift even later in response to the later start time, and in a matter of weeks they would find it just as hard to get out of bed. The results did, however, lend some support to delaying school start in the US, where many schools start as early as 7am.

The mathematical explanation has its roots in the work of the 17th century Dutch mathematician Huygens. He saw that clocks can synchronise, but it depends on both the clocks and how they influence each other. From research over the last few decades we know that body clocks typically run a little slow, so they need to be regularly ‘corrected’ if they are to remain in sync with the 24-hour day. Historically, this correcting signal came from our interaction with the environmental light/dark ‘clock’.

The mathematical model shows that the problem for adolescents is that their light consumption behaviour interferes with the natural interaction with the environmental clock — getting up late in the morning results in adolescents keeping the lights on until later at night. Having the lights on late delays the biological clock, making it even harder to get up in the morning. The mathematics also suggests that the biological clocks of adolescents are particularly sensitive to the effects of light consumption.

The model suggests that an alternative remedy to moving school start times in the UK is exposure to bright light during the day, turning the lights down in the evening and off at night. For very early start times, as in some US regions, any benefit gained from delaying school start times could be lost unless it is coupled with strict limits on the amount of evening artificial light consumption.

Lead author Dr Anne Skeldon said: “The power of the mathematics is that we are able to use existing knowledge about how light interacts with the biological clock to make predictions about different interventions to help reduce ‘social jetlag’.

“It highlights that adolescents are not ‘programmed’ to wake up late and that by increasing exposure to bright light during the day, turning lights down in the evening and off at night should enable most to get up in time for work or school without too much effort and without changing school timetables.”

Co-author Dr Andrew Phillips said: “The most interesting part of this analysis for me was the counter-intuitive finding that the most extreme evening types are predicted to derive the least benefit from a delay in school start times, because they tend to use evening artificial light for a longer interval of time.

“For evening types, it is critical to keep evening light levels low to derive any of the potential benefits of a delay in morning alarm times, otherwise their bed time is very prone to shifting later. Understanding these individual differences, and how they are influenced by light consumption, is necessary to maximize the effects of any policy change.”

Co-author Prof Derk-Jan Dijk said: “Just as mathematical models are used to predict climate change, they can now be used to predict how changing our light environment will influence our biological rhythms.

“It shows that modern lifestyles make it hard for body clocks to stay on 24 hours, which shifts our rhythm of sleepiness and alertness to later times — meaning we are sleepy until late in the morning and remain alert until later in the evening.

“As a result, during the working week our alarm clocks go off before the body clock naturally wakes us up. We then get insufficient sleep during the week and compensate for it during the weekend. Such patterns of insufficient and irregular sleep have been associated with various health problems and have been termed ‘social jet lag’.”

The mathematical understanding of biological clocks suggests that adolescents are particularly sensitive to the effects of light consumption. However, the model can be applied to other age-groups as well. It can be used to design new interventions not only for sleepy teenagers but also for adults who suffer from delayed sleep phase disorders or people who are not synchronised to the 24-hour day at all.

The research draws attention to light, light consumption and darkness as important environmental and behavioural factors influencing health. This has implications for how we design the light environment at work and at home in our modern light-polluted societies.

Source:Science Daily

{Nearly half of all US adolescents aged 13 to 19 are sexually active. But black adolescents, who represent only 14 percent of that population, account for 63 percent of new cases of HIV among adolescents. In addition, it’s estimated that more than 2 million adolescents, many of whom are sexually active, experience a major depressive episode. Could unique psychological factors that hamper emotional regulation help explain differences in HIV/STI risk-related sexual behaviors among heterosexually active black youth with mental illnesses?}

A new University of Pennsylvania School of Nursing (Penn Nursing) study has investigated this question. The findings suggest that psychoeducation and skills building may help sever the emotion-behavior link that contributes to HIV/STI risk among this demographic. The study, “Feelings Matter: Depression Severity and Emotion Regulation in HIV/STI Risk-Related Sexual Behaviors,” which has been published in the Journal of Child and Family Studies, was designed to examine contextual factors related to HIV/STI risk among heterosexually active black adolescents with mental illnesses. It explicitly focused on depression and emotion regulation to uncover how these factors in?uence sexual decision-making.

“Blacks, adolescents, and people with mental illnesses are all disproportionately affected by HIV/STIs,” explains the study’s lead author Bridgette M. Brawner, PhD, APRN, Assistant Professor of Nursing in the Department of Family and Community Health. “We know that the unique psychopathology of mental illness, including impulsivity and engaging in unprotected sex to alleviate depressed mood, may heighten one ‘s HIV/STI risk. Our study indicates we need to better understand unique HIV/STI prevention needs among black adolescents with mental illnesses and that improving coping mechanisms to help regulate emotion should be addressed in HIV/STI prevention research.”

Source:Science Daily

{Study shows how mammal jaws evolved to help our earliest ancestors eat a more diversified diet}

You probably haven’t given much thought to how you chew, but the jaw structure and mechanics of almost all modern mammals may have something to do with why we’re here today. In a new paper published this week in Scientific Reports, David Grossnickle, a graduate student in the Committee on Evolutionary Biology at the University of Chicago, proposes that mammal teeth, jaw bones and muscles evolved to produce side-to-side motions of the jaw, or yaw, that allowed our earliest ancestors to grind food with their molars and eat a more diversified diet. These changes may have been a contributing factor to their survival of the mass extinction at the end of the Cretaceous Period 66 million years ago.

The terms “pitch” and “yaw” usually describe movements of airplanes, but biologists also use them to describe basic movements of body parts such as the jaw. Pitch rotation results in basic up and down movement, and yaw rotation results in side-to-side, crosswise motion (think of a cow munching away on some grass). Almost all modern mammals, including placental mammals, like humans and deer, and marsupials, like kangaroos and opossums, share similarities in their jaw structures and musculature that allow for both pitch and yaw movements. This allows mammals to have especially diverse diets today, from cutting pieces of meat to grinding tough plants and vegetables. For early mammals, these characteristics meant they could be more resourceful during tough times.

“If you have a very specialized diet you’re more likely to perish during a mass extinction because you’re only eating one thing,” Grossnickle said. “But if you can eat just about anything and 90 percent of your food goes away, you can still live on scraps.”

Using 2D images of early mammal fossils from previous publications and 3D data collected from modern specimens at the Field Museum, Grossnickle analyzed the structure of teeth, jaw bones, and how the muscles that control them were attached to the skull. He saw that as species began to develop a projection on the upper molars that fit into a corresponding cup or basin on their lower counterparts, the musculature of the jaw also changed to provide greater torque for side-to-side yaw movements. This way the animal could grind its food between the molars like a mortar and pestle, as opposed to cutting it with simple up and down pitch movements.

Grossnickle, who works in the lab of Zhe-Xi Luo, PhD, professor of organismal biology and anatomy, studies the early origins of mammals, and is interested in broader questions about why certain mammal groups have diversified through time and survived extinction events. He says the adaptations of the jaws and teeth may have been key.

“Mammals rebounded from those events and kept diversifying and persisting, and that’s one of my interests. Why are we in the Age of Mammals, not still in the Age of Dinosaurs?” he said. “This study begins to address that question from a functional perspective, looking at what changes occurred that might’ve given some mammals functional or dietary advantages over other groups.”

Source:Science Daily

{For mothers of new infants, going back to work may pose a number of obstacles to continued breastfeeding. Workplace policies affecting the ability to breastfeed — and the role of nurse practitioners (NPs) in helping to overcome those obstacles — are the topic of a special article in The Nurse Practitioner, published by Wolters Kluwer.}

“Breastfeeding yields many important benefits to both mother and infants, yet workplace barriers contribute to low rates of breastfeeding,” according to the article by Rhonda Winegar, DNP, RN, FNP-BC, CPN, CCRN, and Alisha Johnson, MSN, RN. “Nurse practitioners often serve as the initial point of education for new mothers and may impact decisions to breastfeed.”

Workplace Policies May Make It Harder for Women to Continue Breastfeeding

Breastfeeding is widely recommended as the best nutrition for infants, providing health benefits for babies and mothers alike. As such, measures to encourage breastfeeding have the potential to lower healthcare costs. “Society in general benefits from mothers and infants who are healthier,” according to the authors.

But while 75 percent of women choose breastfeeding after delivery, only 40 percent will continue breastfeeding after they return to work. “In the United States, breastfeeding is considered a personal choice, and legislation in support of breastfeeding in the workplace is more limited than in most other countries,” Rhonda Winegar and Alisha Johnson write.

Employer policies can have a major impact on women’s ability to continue breastfeeding after returning to work. One study found that women who work at companies with policies to support breastfeeding are more likely to continue breastfeeding for at least six months, as recommended by current guidelines.

The article identifies key elements of a successful workplace breastfeeding policy include providing appropriate breaks and a suitable area for women to pump breast milk, as well as a storage facility for the expressed milk (such as a refrigerator), if requested. The costs of such policies are relatively low — and are likely to be offset by the potential savings from fewer employee absences, lower healthcare costs, and less employee turnover.

And yet, employers may be unlikely to adopt breastfeeding promotion programs unless there are regulations to support them. The ‘Break Time for Nursing Mothers’ provision of the Affordable Care Act includes protections covering some employees and workplaces. In addition, 28 states (along with Puerto Rico and the District of Columbia) have laws in place regarding breastfeeding in the workplace. “Nurse practitioners should stay current on current legislation and community resources that are available to support breastfeeding once these patients return to work,” the authors write.

Other steps to promote continued breastfeeding range from prescribing an electric breast pump or arranging for a lactation consultant, to dealing with common concerns such as milk leakage on work clothes. Rhonda Winegar and Alisha Johnson conclude, “NPs can positively influence the incidence of breastfeeding and ultimately improve the health of society in general.”

The article appears as part of a special Doctor of Nursing Practice (DNP) theme issue of The Nurse Practitioner. In a video podcast, Rhonda Winegar discusses the personal experiences that led to her advocacy for policies to support breastfeeding in the workplace, and inspired her to become a DNP.

Source:Science Daily

{After a rough night’s sleep, your ability to recognize whether those around you are happy or sad could suffer, according to a study led by a University of Arizona psychologist.}

The research, published in the journal Neurobiology of Sleep and Circadian Rhythms, found that study participants had a harder time identifying facial expressions of happiness or sadness when they were sleep deprived versus well-rested.

The sleepy participants’ ability to interpret facial expressions of other emotions — anger, fear, surprise and disgust — was not impaired, however. That’s likely because we’re wired to recognize those more primitive emotions in order to survive acute dangers, said lead researcher William D.S. Killgore, a UA professor of psychiatry, psychology and medical imaging.

While emotions such as fear and anger could indicate a threat, social emotions such as happiness and sadness are less necessary for us to recognize for immediate survival. When we’re tired, it seems we’re more likely to dedicate our resources to recognizing those emotions that could impact our short-term safety and well-being, Killgore said.

“If someone is going to hurt you, even when you’re sleep deprived you should still be able to pick up on that,” Killgore said. “Reading whether somebody is sad or not is really not that important in that acute danger situation, so if anything is going to start to degrade with lack of sleep it might be the ability to recognize those social emotions.”

The data used in the study was part of a larger research effort on sleep deprivation’s effects on social, emotional and moral judgment. Killgore began the project while working as a research psychologist for the U.S. Army.

The current study is based on data from 54 participants, who were shown photographs of the same male face expressing varying degrees of fear, happiness, sadness, anger, surprise and disgust. Participants were asked to indicate which of those six emotions they thought was being expressed the most by each face.

In order to assess participants’ ability to interpret more subtle emotional expressions, the images presented were composite photos of commonly confused facial expressions morphed together by a computer program. For example, a face might show 70 percent sadness and 30 percent disgust or vice versa. Participants saw a total of 180 blended facial expressions at each testing session.

Participants’ baseline responses to the images were compared to their responses after they were deprived of sleep for one night.

Researchers found that blatant facial expressions — such as an obvious grin or frown (90 percent happy or 90 percent sad) — were easily identifiable regardless of how much sleep a participant got. Sleep deprived participants had a harder time, however, correctly identifying more subtle expressions of happiness and sadness, although their performance on the other emotions was unchanged.

When participants were tested again after one night of recovery sleep, their performance on happiness and sadness improved, returning to its baseline level.

While the difference in performance was not overwhelming, it’s enough that it could have a significant impact in critical social interactions, Killgore said.

“As a society, we don’t get the full seven to eight hours of sleep that people probably need to be getting. The average American is getting a little less than six hours of sleep on average, and it could affect how you’re reading people in everyday interactions,” Killgore said. “You may be responding inappropriately to somebody that you just don’t read correctly, especially those social emotions that make us human. Or you may not be as empathic. Your spouse or significant other may need something from you and you’re less able to read that. It’s possible that this could lead to problems in your relationships or problems at work. To me, that is one of the biggest problems — how this affects our relationships.”

Killgore’s research builds on existing work on the effects of sleep deprivation on the brain’s ventromedial prefrontal cortex — an area that helps people make judgments and decisions using their emotions.

A prior study, published by Harvard’s Seung-Schik Yoo and colleagues, showed that when people are sleep deprived, a disconnect occurs between the prefrontal cortex and the amygdala — one of the key emotionally responsive areas of the brain.

“So, in simplistic terms, the part of the brain that controls your emotions and the part that sees faces and responds to the emotional content basically start to lose their ability to communicate,” Killgore said. “We wanted to test that out and see if it plays out in terms of how people read facial expressions — and, in fact, it looks like it does.”

Source:Science Daily

{Results open the door to producing a diversity of new cell types that could not be made before.}

Wellcome Trust Sanger Institute scientists and their collaborators at the University of Cambridge have created a new technique that simplifies the production of human brain and muscle cells — allowing millions of functional cells to be generated in just a few days. The results published in Stem Cell Reports open the door to producing a diversity of new cell types that could not be made before in order to study disease.

Human pluripotent stem cells offer the ability to create any tissue, including those which are typically hard to access, such as brain cells. They hold huge potential for studying human development and the impact of diseases, including cancer, Alzheimer’s, Multiple Sclerosis, and heart disease.

In a human, it takes nine to twelve months for a single brain cell to develop fully. To create human brain cells, including grey matter (neurons) and white matter (oligodendrocytes) from an induced pluripotent stem cell, it can take between three and twenty weeks using current methods. However, these methods are complex and time-consuming, often producing a mixed population of cells.

The new platform technology, OPTi-OX, optimises the way of switching on genes in human stem cells. Scientists applied OPTi-OX to the production of millions of nearly identical cells in a matter of days. In addition to the neurons, oligodendrocytes, and muscle cells the scientists created in the study, OPTi-OX holds the possibility of generating any cell type at unprecedented purities, in this short timeframe.

To produce the neurons, oligodendrocytes, and muscle cells, scientists altered the DNA in the stem cells. By switching on carefully selected genes, the team “reprogrammed” the stem cells and created a large and nearly pure population of identical cells. The ability to produce as many cells as desired combined with the speed of the development gives an advantage over other methods. The new method opens the door to drug discovery, and potentially therapeutic applications in which large amounts of cells are needed.

An author of the study, Dr Ludovic Vallier from the Wellcome Trust Sanger Institute said: “What is really exciting is we only needed to change a few ingredients — transcription factors — to produce the exact cells we wanted in less than a week. We over-expressed factors that make stem cells directly convert into the desired cells, thereby bypassing development and shortening the process to just a few days.”

OPTi-OX has applications in various projects, including the possibility to generate new cell types which may be uncovered by the Human Cell Atlas. The ability to produce human cells so quickly means the new method will facilitate more research.

Joint first author, Daniel Ortmann from the University of Cambridge, said: “When we receive a wealth of new information on the discovery of new cells from large scale projects, like the Human Cell Atlas, it means we’ll be able to apply this method to produce any cell type in the body, but in a dish.”

Mark Kotter, lead author and Clinician from the University of Cambridge, said: “Neurons produced in this study are already being used to understand brain development and function. This method opens the doors to producing all sorts of hard-to-access cells and tissues so we can better our understanding of diseases and the response of these tissues to newly developed therapeutics.”

Source:Science Daily

{Researchers say it may seem contradictory that a means of generalizing to people at large is used when reflecting on one’s most personal and idiosyncratic experiences. To cope with negative experiences or to share an insight, people often use the word “you” rather than “I.”}

“You” is an overlooked word that people use to express norms and rules, new University of Michigan research found.

Researchers conducted nine experiments with 2,489 people to understand why people curiously use “you” not only to refer to specific others, but also to reflect on their own experiences.

“It’s something we all do as a way to explain how things work and to find meaning in our lives,” said Ariana Orvell, a doctoral student in the Department of Psychology and the study’s lead author.

“When people use “you” to make meaning from negative experiences, it allows them to ‘normalize’ the experience and reflect on it from a distance,” said Orvell.

For example, “you win some, you lose some” would indicate that a person has failed in a situation, but by using the word ‘you,’ they are able to communicate that this could happen to anyone.

“Or saying that ‘when you are angry, you say and do things that you will most likely regret’ might actually explain a personal situation, but the individual attempts to make it something many people relate to,” Orvell said.

In one experiment, researchers asked participants to write about a personal experience: 201 were asked to make meaning from a negative event, 198 were asked to relive a negative event, and 203 were simply asked to write about a neutral experience. Those in the meaning-making group used generic-you more in their essays (46 percent used the word at least once) than those in the Relive group (10 percent used the word at least once) and the neutral group (3 percent used the word at least once). The researchers also found that using generic-you led people to view the event as more distant.

The researchers say it may seem contradictory that a means of generalizing to people at large is used when reflecting on one’s most personal and idiosyncratic experiences.

“We suspect that it’s the ability to move beyond your own perspective to express shared, universal experiences that allows individuals to derive broader meanings from personal events,” Orvell said.

Orvell collaborated on the study with Ethan Kross, psychology professor, and Susan Gelman, Heinz Werner Distinguished University Professor of Psychology and Linguistics.

The findings appear in the latest issue of Science.

Source:Science Daily

{Genetic mutations that cause cancer also weaken cancer cells, creating an opportunity for researchers to develop drugs that will selectively kill them, while sparing normal cells. This concept is called “synthetic lethality” because the drug is only lethal to mutated (synthetic) cells. Researchers at UC San Diego School of Medicine and Jacobs School of Engineering developed a new method to search for synthetic-lethal gene combinations.}

The technique, published March 20 in Nature Methods, uncovered 120 new opportunities for cancer drug development.

“The ovarian cancer drug olaparib works by synthetic lethality — it inhibits a gene that, when a BRCA gene is also mutated, kills just those cancer cells,” said John Paul Shen, MD, clinical instructor and postdoctoral fellow at UC San Diego School of Medicine and Moores Cancer Center. “Many other cancers could likely be treated this way as well, but we don’t yet know which gene mutation combinations will be synthetic-lethal.” Shen was co-first author of the study, along with Dongxin Zhao, PhD, postdoctoral fellow at UC San Diego Jacobs School of Engineering, and Roman Sasik, PhD, computational biologist in the UC San Diego School of Medicine.

To overcome this limitation, the team developed a new method that uses the gene editing technique CRISPR/Cas9 to simultaneously test for thousands of synthetic-lethal interactions. CRISPR/Cas9 works like this: researchers design a “guide” RNA to match the sequence of a specific target gene in a cell. The RNA guides the Cas9 enzyme to the desired spot, where it cuts the DNA. The cell can repair the DNA break, but it does so imprecisely, thereby inactivating the gene.

In this study, the researchers designed a CRISPR/Cas9 system with two guide RNAs: 1) one that targets a tumor suppressor gene that is commonly mutated in cancer and 2) one that targets a gene that could also be disrupted by a cancer drug. They deployed this system against 73 genes in three laboratory cell lines — human cervical cancer, lung cancer and embryonic kidney cells — for a total of 150,000 gene combinations. Then they measured cell growth and death.

The approach revealed more than 120 new synthetic-lethal interactions.

“Identifying underlying genetic interactions in this way can reveal important functional relationships between genes, such as contributions to the same protein complex or pathway,” co-senior author Trey Ideker, PhD, professor in the UC San Diego School of Medicine, founder of the UC San Diego Center for Computational Biology and Bioinformatics and co-director of the Cancer Cell Map Initiative. “This in turn can impact both our fundamental understanding of biological systems, as well as therapeutics development.”

Many of the gene interactions the team identified were synthetic-lethal in just one of the three cell lines tested. This means that synthetic-lethal interactions may be different in different types of cancer. The researchers said this will be an important consideration for future drug development.

“Moving forward, we intend to further refine our technology platform and make it more robust,” said co-senior author Prashant Mali, PhD, assistant professor in the Jacobs School of Engineering at UC San Diego. “And we are scaling our cancer genetic networks maps so we can systematically identify new combination therapies.”

Source:Science Daily