Why Do Some Fish Thrive in Oil-Polluted Water?

Scientists thought guppies in Northern Trinidad could be a rare example of adaptation to crude oil pollution. But they found something else.

When scientists from McGill University learned that some fish were proliferating in rivers and ponds polluted by oil extraction in Southern Trinidad, it caught their attention. They thought they had found a rare example of a species able to adapt to crude oil pollution.

At a time when humans are imposing an unprecedented burden on the world's ecosystems, studying how organisms can tolerate pollutants is crucial to understanding the impact of human activities – and to helping to mitigate it in the future.

Led by Dr. Gregor Rolshausen, then a postdoctoral researcher at McGill working with Prof. Andrew Hendry, the team went to study the guppy fish living in polluted areas, comparing their morphology and genetic makeup to those of similar guppies from non-polluted parts of Trinidad.

But the key to the guppies’ survival in oil-polluted waters was not what the researchers had expected. Prof. Hendry explains: https://www.youtube.com/watch?v=568hCM-wFZs

Released: 26-Jan-2016 8:05 AM EST 
Source Newsroom: McGill University

Do stressful conditions make adaptation difficult? Guppies in the oil-polluted environments of southern Trinidad, inEvolutionary Applications, Volume 8, Issue 9, pages 854–870, October 2015.
By Gregor Rolshausen, Dawn Phillip, Denise Beckles, Ali Akbari, Subhasis Ghoshal, Patrick Hamilton, Charles Tyler, Alan Scarlett, Indar Ramnarine, Paul Bentzen and Andrew P. Hendry

#Selfie: Researchers Find Instagram Selfie Posts Tied to Romantic Relationship Conflict

Florida State University researchers have discovered the more selfies an individual posts on the social media site Instagram, the greater the likelihood he or she might experience romantic relationship conflict and dissolution.

Jessica Ridgway, lead author and visiting assistant professor of Retail Merchandising and Product Development, and Russell Clayton, an assistant professor in the School of Communication, teamed up to examine the predictors and consequences associated with Instagram selfie posting.

“Although we cannot directly assume cause and effect due to the correlational nature of this study, the results here show that body image satisfaction can be detrimental to Instagram users’ romantic relationships, especially when users’ body image satisfaction is promoted in the form of Instagram selfie posts,” Clayton said.

The study, recently published in the journal Cyberpsychology, Behavior, and Social Networking, contributes to a growing body of scholarly literature that has examined the predictors and consequences associated with using social media sites such as Facebook and Twitter.

With an online survey of 420 Instagram users between the ages of 18 to 62, the researchers found that Instagram selfie posting is associated with and predicted by an individual’s overall body image satisfaction. In other words, those who think they look good are more likely to post selfies.

However, Instagram selfie posting behaviors were found to be associated with increased Instagram-related relationship conflict. The researchers defined Instagram-related conflict as jealousy and arguments occurring due to either or both partners’ Instagram selfie posting behaviors.

Not surprisingly, Instagram-related conflict was found to be associated with increased negative romantic relationship outcomes, which were defined as emotional or physical infidelity, breakup and divorce.

“The results from this study provide an avenue for future body image research,” Ridgway said. “For instance, future research could examine whether social media users post images of their actual selves or their virtual ideal selves, and whether such online behaviors are associated with similar negative outcomes found in our study.”

In order to prevent negative relationship outcomes from arising, Ridgway and Clayton recommend that Instagram users limit their selfie-posting behaviors, especially when selfie-posting becomes problematic in a user’s romantic relationship.

Released: 22-Jan-2016 1:05 PM EST 
Source Newsroom: Florida State University

Study: Controlling Parents Create Mean College Kids

College students whose parents lay on the guilt or try to manipulate them may translate feelings of stress into similar mean behavior with their own friends, a new study by a University of Vermont psychologist has found.

College students whose parents lay on the guilt or try to manipulate them may translate feelings of stress into similar mean behavior with their own friends, a new study by a University of Vermont psychologist has found.

Those students’ physical response to stress influences the way they will carry out that hostility – either immediately and impulsively or in a cold, calculated way, concluded Jamie Abaied, a UVM assistant professor of psychological science.

Building on her previous research on the effects of various parenting styles on college-age children, Abaied looked at the link between “parental psychological control” and the young adults’ relationships with peers. Her study, published by the Journal of Youth and Adolescence, involved 180 mostly female college students and was a collaboration with Abaied’s graduate research assistant, Caitlin Wagner, the lead author on the paper.

Even after they leave home as legal adults, college students often still depend on parents for financial, as well as emotional, support. Some parents will nit-pick and find fault or threaten to withdraw affection (or money) as punishment or to force a desired outcome. With today’s technology, parents can exercise that control wherever their kids go – with texts, email and social media keeping them in constant contact.

“You can do that from far away,” Abaied says. “You don’t have to be in person to manipulate your kids’ thoughts and emotions.”

The result can stunt their budding independence, Abaied concluded. “We need to be really mindful of how influential the parents are.”

College students are less studied in relation to parental control, Abaied says, though psychologists have long recognized that heavy-handed parents trigger “relational aggression” in their children. Relational aggression involves a relationship with a friend or loved one and actions that harm feelings or damage social status: exclusion from a social event, rumor-mongering, backstabbing or public embarrassment.

With younger children, one might not invite another to a birthday party. Adolescents might try to embarrass or ostracize a peer, as in the “Mean Girls” movie about a high-school outsider who infiltrates then obliterates a popular female clique.
Abaied’s study is unique in that it factored physiology, specifically the physical response to stress, in the way the student carries out relational aggression. In her UVM lab, Abaied and her researchers attached sensors to the students’ fingers to measure miniscule changes in sweat. Perspiration indicates the ramping up of the sympathetic nervous system – along with an elevated heart rate and increased oxygen flow – as the body’s adaptation to perceived stress, also known as the “fight or flight” response.

In carefully crafted interviews, researchers asked the students to describe a painful event involving a close person, perhaps an argument with a roommate or a breakup with a boyfriend or girlfriend, and recorded their sweat levels. “Basically, we were trying to get them to relive” the difficult experience, Abaied says, “just to get their bodies to demonstrate their stress response to us.”

Those who perspired more, indicating “high arousal,” got more upset. They were more hot-tempered and likely to react quickly with less thought – the types who hit the “send” button on a nasty email right away.

Those who sweated less, with “blunted arousal,” stayed cool and collected and were more likely to think through an aggressive response. “If you’re calm, you can be strategic and planned in your aggression,” Abaied says. “You can really use your aggression to control your relationship and stay dominant over your peers.”

To determine the level of parental control, the students completed a questionnaire. Higher control correlated with higher aggression. Less-controlling parents created less aggression,

Abaied says.
“It seems like good parenting protects them,” she says of college students. “Good parenting prevents them from being aggressive in their peer relationships.”

Released: 21-Jan-2016 7:05 AM EST 
Source Newsroom: University of Vermont

Descendants of Black Death Confirmed as Source of Repeated European Plague Outbreaks That Would Fade and Roar Back Over Centuries: Research

Illustration of the Black Death from the Toggenburg Bible (1411)

An international team of researchers has uncovered new information about the Black Death in Europe and its descendants, suggesting it persisted on the continent over four centuries, re-emerging to kill hundreds of thousands in Europe in separate, devastating waves.

The findings address the longstanding debate among scientists about whether or not the bacterium Yersinia pestis –responsible for the Black Death—remained within Europe for hundreds of years and was the principal cause of some of the worst re-emergences and subsequent plague epidemics in human history.

Until now, some researchers believed repeated outbreaks were the result of the bacterium being re-introduced through major trade with China, a widely-known reservoir of the plague. Instead, it turns out the plague may never have left.

“The more plague genomes we have from these disparate time periods, the better we are able to reconstruct the evolutionary history of this pathogen” says evolutionary geneticist Hendrik Poinar, director of McMaster University’s Ancient DNA Centre and a principal investigator at the Michael G. DeGroote Institute for Infectious Disease Research.

Poinar collaborated with Edward Holmes at the University of Sydney, Olivier Dutour of the École Pratique des Hautes Études in France, and Kirsti Bos and Johannes Krause at the University of Tubingen, and others, to map the complete genomes of Y.pestis which was harvested from five adult male victims of the 1722 Plague of Provence.

To do so, they analyzed the dental pulp taken from the five bodies, originally buried in Marseille, France. Researchers were able to extract, purify and enrich specifically for the pathogen’s DNA, and then compare the samples with over 150 plague genomes representing a world wide distribution as well as from other points in time, both modern and ancient.

By comparing and contrasting the samples, researchers determined the Marseille strain is a direct descendant of the Black Death that devastated Europe nearly 400 years earlier and not a divergent strain that came, like the previous pandemic strains Justinian and Black Death, from separate emergences originating in Asia.

More extensive sampling of modern rodent populations, in addition to ancient human and rodent remains from various regions in Asia, the Caucasus and Europe, may yield additional clues about past ecological niches for plague.

“There are many unresolved questions that need to be answered: why did the plague erupt in these devastating waves and then lay dormant? Did it linger in the soil or did it re-emerge in rats? And ultimately why did it suddenly disappear and never come back? Sadly, we don’t have the answer to this yet,” says Poinar.

“Understanding the evolution of the plague will be critically important as antibiotic resistance becomes a greater threat, particularly since we treat modern-day plague with standard antibiotics. Without methods of treatment, easily treatable infections can become devastating again,” he says.

The research was published online in the journal eLife.

Released: 25-Jan-2016 8:05 AM EST 
Source Newsroom: McMaster University

1 in 7 Colorectal Cancer Patients Diagnosed Before Recommended Screening Age

1 in 7 colorectal cancer patients diagnosed before recommended screening age

Colorectal cancer in younger people linked to more advanced disease but better survival

Nearly 15 percent of patients diagnosed with colorectal cancer were younger than 50, the age at which screening recommendations begin.

The study by researchers at the University of Michigan Comprehensive Cancer Center also found that younger patients were more likely to have advanced disease. The authors suggest this is in part because they are diagnosed only after their cancers have grown large enough to cause symptoms.

“Colorectal cancer has traditionally been thought of as a disease of the elderly. This study is really a wake-up call to the medical community that a relatively large number of colorectal cancers are occurring in people under 50,” says study author Samantha Hendren, M.D., M.P.H., associate professor of surgery at the University of Michigan Medical School.

“To put this in context, breast cancer screening often begins at age 40, and less than 5 percent of invasive breast cancers occur in women under that age. Our study found that about 15 percent of colorectal cancers are diagnosed before the screening age of 50,” she adds.

The study identified 258,024 patients diagnosed with colon or rectal cancer from the Surveillance, Epidemiology and End Results database, a national database of cancer incidence. Results appear in the journal Cancer.

The authors found that younger patients were more likely to receive aggressive surgery and radiation therapy. In addition, this group had better survival rates, both overall and by stage. Among patients whose cancer had spread to distant organs, 21 percent of younger patients survived beyond five years, compared to 14 percent of older patients.

The improved survival could be in part due to the more aggressive treatment, the authors suggest.

The findings suggest the need for more awareness of warning signs of colorectal cancer: anemia, a dramatic change in the size or frequency of bowel movements, and bleeding with bowel movements. The authors also say that more people need to consider family history of colorectal cancer, which is a significant risk factor.

Should guidelines change to begin screening at an earlier age? Hendren says not so fast.

“This would be a big and costly change, and I don’t know whether it would help more people than it would hurt,” she says. “A lot of research would be required to understand this before any changes should be made.”

Meanwhile, the more aggressive treatment and longer survival for younger patients suggest the need to improve long-term survivorship resources.

“The cancer community needs to prepare for the increasing number of very young colorectal cancer survivors who will need long-term support to cope with the physical and psychological consequences of their disease and treatments,” Hendren says.

Empathy more common in animals than thought

A new study reveals that prairie voles console loved ones who are feeling stressed - and it appears that the infamous "love hormone," oxytocin, is the underlying mechanism.

Until now, consolation behavior has only been documented in a few nonhuman species with high levels of sociality and cognition, such as elephants, dolphins and dogs.

Prairie voles are particularly social rodents, causing them to be the focus of many studies.

This led James Burkett and colleagues to explore their potential for empathy-motivated behaviors. The researchers created an experiment where relatives and known individuals were temporarily isolated from each other, while one was exposed to mild shocks.

Upon reunion, the non-stressed prairie voles proceeded to lick the stressed voles sooner and for longer durations, compared to a control scenario where individuals were separated but neither was exposed to a stressor.

Measurements of hormone levels revealed that the family members and friends were distressed when they could not comfort their loved one.

The fact that consoling behavior occurred only between those who were familiar with each other -- including non-kin members -- but not strangers, demonstrates that the behavior is not simply a reaction to aversive cues, the authors note.

Since the oxytocin receptor is associated with empathy in humans, Burkettet al. blocked this neurotransmitter in prairie voles in a series of similar consolation experiments.

Blocking oxytocin did not cause family members and friends to alter their self-grooming behavior, yet they did cease consoling each other.

These findings provide new insights into the mechanisms of empathy and the evolution of complex empathy-motivated behaviors.

Source: Empathy more common in animals than thought

Young men have lower aerobic fitness if their mothers smoked during pregnancy

Mothers who smoke are putting more than their own health at risk, suggests a study published today in BJOG. Young men whose mothers smoked during pregnancy had lower aerobic fitness compared to those whose mothers did not.

For the first time, a small Finnish study has examined the impact of maternal smoking on the long-term health of male offspring. Of the 508 young men (average age 19) included in the study 59 of their mothers smoked more than one cigarette a day throughout pregnancy. Results found that maternal smoking was associated with lower aerobic fitness of their children, which was measured by ability on a running test at the beginning of their military service assessment. Aerobic activity was also independently associated with their own smoking status, weight and physical activity.

The study also found that higher maternal pre-pregnancy BMI and excessive weight gain during pregnancy were associated with lower aerobic fitness in the offspring.

Dr Maria Hagnäs from the University of Oulu, Finland, and lead author of the study said:

"It’s well established that smoking and breathing in second-hand smoke are harmful for both mother and baby. Our study adds to the existing evidence base of the negative and long-standing impacts of maternal smoking. Women must receive advice and support to help them stop smoking during pregnancy, as well guidance on how to maintain a healthy weight to minimise the risks to their unborn child.”

The health risks associated with smoking, and the benefits of stopping smoking, are well known. Mothers who smoke are at a higher risk of miscarriage, ectopic pregnancy, intrauterine growth restriction, premature birth and stillbirth. Their babies are also more likely to suffer from birth defects, and neurological, psychological or behavioural difficulties. In addition, babies born to mothers who smoke have a greater risk of asthma, chest and ear infections and pneumonia as well as being more susceptible to infant death syndrome. Although more likely to be small babies, they are at increased risk of obesity and insulin resistance (the precursor of diabetes) later in life.

Dr Geeta Kumar, Chair of the RCOG’s Patient Information Committee, said:

“Stopping smoking is one of the most important things a pregnant woman can do to improve their baby’s health, growth and development, and this study demonstrates the negative effect smoking in pregnancy can have on a child’s long-term health too.

“It is important that women understand the risks of smoking in pregnancy and are aware of the support that is available to help them stop. Women who are unable to quit smoking should be encouraged to abstain during their pregnancy, use nicotine replacement therapy, or to reduce smoking as much as they can. We encourage all healthcare professionals working with pregnant women to access the RCOG’s new patient information leaflet which contains practical and evidence-based advice and guidance to share with women about smoking during pregnancy.”

Full paper: Hagnäs MP, Cederberg H, Jokelainen J, Mikkola I, Rajala U, Keinänen-Kiukaanniemi S. Association of maternal smoking during pregnancy with aerobic fitness of offspring in young adulthood: a prospective cohort study. BJOG 2015;DOI: 10.1111/1471-0528.13789.

Source: http://www.bjog.org/details/news/8650421/Young_men_have_lower_aerobic_fitness_if_their_mothers_smoked_during_pregnancy.html

Depression of either parent during pregnancy linked to premature birth

Depression in both expectant mothers and fathers increases the risk of premature birth, finds a study published in BJOG: an International Journal of Obstetrics and Gynaecology (BJOG).

Depression in women during pregnancy is known to be associated with low birthweight and increased risk of premature birth. Maternal stress, such as the death of a loved one, lack of social support, or a difficult or abusive relationship, has also been shown to increase the risk of premature birth. However, little research has examined the impact of paternal depression on the health of the mother or the unborn child.

In this study, more than 350,000 births in Sweden between 2007 and 2012 were investigated for parental depression and incidences of either very preterm birth (between 22 and 31 weeks) or moderately preterm birth (32-36 weeks).

For both men and women, depression was defined as having had a prescription of antidepressant medication, or receiving outpatient/inpatient hospital care, from 12 months before conception to the end of the second trimester of pregnancy. People with depression were classed as ‘new’ cases if they had had no depression in the 12 months prior to diagnosis, all other cases were defined as ‘recurrent’ depression.

While both new and recurrent depression in the mothers was associated with an increased risk of moderately preterm birth of around 30% to 40%, new depression in the fathers was associated with a 38% increased risk of very preterm birth. Recurrent depression in the fathers was not associated with preterm birth at all.

Professor Anders Hjern, from the Centre for Health Equity Studies in Stockholm (CHESS), said:

“Depression of a partner can be considered to be a substantial source of stress for an expectant mother, and this may result in the increased risk of very preterm birth seen in our study. Paternal depression is also known to affect sperm quality, have epigenetic effects on the DNA of the baby, and can also affect placenta function. However, this risk seems to be reduced for recurrent paternal depression, indicating that perhaps treatment for the depression reduces the risk of preterm birth.

“For the mothers, depression increased the risk of preterm birth, regardless of whether the depression was new or recurrent.

“Our results suggest that both maternal and paternal depression should be considered in preterm birth prevention strategies and both parents should be screened for mental health problems. Since men are less likely to seek professional help for any mental health problems, a proactive approach towards targeting the wellbeing of expectant fathers may be beneficial.”

John Thorp, BJOG Deputy Editor-in-chief, added:

"This study highlights the importance of treating depression for both men and women, and the impact untreated depression can have on the health of offspring.

"Further progress is needed into the understanding of how depression of either parent affects pregnancy in order to help prevent preterm birth.”

Dr Patrick O’Brien, an obstetrician and spokesperson for the Royal College of Obstetricians and Gynaecologists (RCOG), said:

“Depression in pregnancy can be very serious for a woman and can also impact on the health of her baby. We know that between 12% and 20% of women experience anxiety and/or depression during pregnancy and the first year after childbirth.

“This research is interesting as it finds that paternal mental health can also have an effect on the health of the baby. However, more research is needed to establish the mechanism behind this effect.

“We encourage anyone, and particularly those planning a family or who are pregnant, and are experiencing a change in mood, irritability or anxiety to seek advice. No one should suffer in silence - there is help and support available.”

Full paper: Can Liu, Sven Cnattingius, Malin Bergström, Viveca Östberg, Anders Hjern. Prenatal parental depression and preterm birth: A national cohort study. BJOG 2015; DOI: 10.1111/1471-0528.13891

Cells talk to their neighbors before making a move

Cells trade information with adjoining cells and, like the telephone game, the original message becomes garbled the further it travels down the line.

To decide whether and where to move in the body, cells must read chemical signals in their environment. Individual cells do not act alone during this process, two new studies on mouse mammary tissue show. Instead, the cells make decisions collectively after exchanging information about the chemical messages they are receiving.

“Cells talk to nearby cells and compare notes before they make a move,” saysIlya Nemenman, a theoretical biophysicist at Emory University and a co-author of both studies, published by the Proceedings of the National Academy of Sciences (PNAS). The co-authors also include scientists from Johns Hopkins, Yale and Purdue.

The researchers discovered that the cell communication process works similarly to a message relay in the telephone game. “Each cell only talks to its neighbor,” Nemenman explains. “A cell in position one only talks to a cell in position two. So position one needs to communicate with position two in order to get information from the cell in position three.”

And like the telephone game – where a line of people whisper a message to the person next to them – the original message starts to become distorted as it travels down the line. The researchers found that, for the cells in their experiments, the message begins to get garbled after passing through about four cells, by a factor of about three.

“We built a mathematical model for this linear relay of cellular information and derived a formula for its best possible accuracy,” Nemenman says. “Directed cell migration is important in processes from cancer to the development of organs and tissues. Other researchers can apply our model beyond the mouse mammary gland and analyze similar phenomena in a wide variety of healthy and diseased systems.”

Since at least the 1970s, and pivotal work by Howard Berg and Ed Purcell, scientists have been trying to understand in detail how cells decide to take an action based on chemical cues. Every cell in a body has the same genome but they can do different things and go in different directions because they measure different chemical signals in their environment. Those chemical signals are made up of molecules that randomly move around.

“Cells can sense not just the precise concentration of a chemical signal, but concentration differences,” Nemenman says. “That’s very important because in order to know which direction to move, a cell has to know in which direction the concentration of the chemical signal is higher. Cells sense this gradient and it gives them a reference for the direction in which to move and grow.”

Berg and Purcell understood the best possible margin of error – the detection limit – for such gradient sensing. During the subsequent 30 years, researchers have established that many different cells, in many different organisms, work at this detection limit. Living cells can sense chemicals better than any man-made device.

It was not known, however, that cells can sense signals and make movement decisions collectively.

“Previous research has typically focused on cultured cells,” Nemenman says. “And when you culture cells, the first thing to go away is cell-to-cell interaction. The cells are no longer a functioning tissue, but a culture of individual cells, so it’s difficult to study many collective effects.”

The first PNAS paper drew from three-dimensional micro-fluidic techniques from the Yale University lab of Andre Levchenko, a biomedical engineer who studies how cells navigate; research on mouse mammary tissue at the Johns Hopkins lab of Andrew Ewald, a biologist focused on the cellular mechanisms of cancer; and the quantification methods of Nemenman, who studies the physics of biological systems, and Andrew Mugler, a former post-doctoral fellow in Nemenman’s lab at Emory who now has his own research group at Purdue.

The 3D micro fluidics allowed the researchers to experiment with functional organoids, or clumps of cells. The method does not disrupt the interaction of the cells. The results showed that epidermal growth factor, or EGF, is the signal that these cells track, and that the cells were not making decisions about which way to move as individuals, but collectively.

“The clumps of cells, working collectively, could detect insanely small differences in concentration gradients – such as 498 molecules of EGF versus 502 molecules – on different sides of one cell,” Nemenman says. “That accuracy is way better than the best possible margin of error determined by Berg and Purcell of about plus or minus 20. Even at these small concentration gradients, the organoids start reshaping and moving toward the higher concentration. These cells are not just optimal gradient detectors. They seem super optimal, defying the laws of nature.”

Collective cell communication boosts their detection accuracy, turning a line of about four cells into a single, super-accurate measurement unit.

In the second PNAS paper, Nemenman, Mugler and Levchenko looked at the limits to the cells’ precision of collective gradient sensing not just spatially, but over time. “We hypothesized that if the cells kept on communicating with one another over hours or days, and kept on accumulating information, that might expand the accuracy further than four cells across,” Nemenman says. “Surprisingly, however, this was not the case. We found that there is always a limit of how far information can travel without being garbled in these cellular systems.”

Together, the two papers offer a detailed model for collective cellular gradient sensing, verified by experiments in mouse mammary organoids. The collective model expands the classic Berg-Purcell results for the best accuracy of an individual cell, which stood for almost forty years. The new formula quantifies the additional advantages and limitations on the accuracy coming from the cells working collectively.

“Our findings are not just intellectually important. They provide new ways to study many normal and abnormal developmental processes,” Nemenman says.

Popular Posts