Week in Review: June 29–July 3

Sex differences in processing pain; clue in flu vaccine–narcolepsy link found; early antibiotic use affects the gut microbiome; lizard sex determined by genes, then temperature

Jul 3, 2015
Jef Akst

Sexes perceive pain differently

PIXABAY, KAPA65Male and female mice use different immune cells to process pain, according to a study published this week (June 29) in Nature Neuroscience. Male mice feel pain through cells called microglia, while female mice tend to use T cells, though they will switch to using microglia when they lack adaptive immune cells.

“The finding that microglia are not required for pain sensitivity in female mice is really exciting,” University of Kentucky neurobiologist Bradley Taylor, who was not involved in the study, told The Scientist.

“This is not the usual type of sex difference that people usually report,” said study coauthor Jeffrey Mogil, a pain geneticist at McGill University in Montreal. “It’s astoundingly robust.”

Is a flu vaccine causing narcolepsy?

WIKIMEDIA, KHOA PELCZARGlaxoSmithKline’s Pandemrix vaccine for H1N1 has been linked to an increased risk of narcolepsy in children immunized in a 2009 vaccination campaign in Europe. Scientists suspected that something in the vaccine, or perhaps something in the virus itself, was eliciting an immune response that caused the body to attack its own hypocretin pathway, which regulates sleep. Now, researchers have identified a peptide, a portion of the influenza virus nucleoprotein A, found in high abundance in Pandemrix that resembles hypocretin receptor peptide. Moreover, patients who were vaccinated with Pandemrix had high levels of antibodies that bound both the influenza peptide and the hypocretin receptor.

The results, published this week (July 1) in Science Translational Medicine, suggest that the vaccine may spur the production of self-reactive antibodies that leads to narcolepsy. But the virus itself could also be triggering an autoimmune reaction. Indeed, the antibodies were present in five of 20 blood samples from patients who were infected with swine flu in 2009. “I think the field is wide open at this point,” said Thomas Scammell, a neurologist at Harvard Medical School in Boston, Massachusetts, who was not involved in the research.

Effects of early antibiotic use

WIKIMEDIA, SAGE ROSSTherapeutic doses of common antibiotics given to newborn mice resulted in changes to the gut microbiome as well as to body mass and bone growth, according to a study published this week (June 30) in Nature Communications.

“While this is a correlative study, [the researchers] present a plausible case that antibiotics, by changing the gut microbiota, may affect host function,” said Lee Kaplan, a gastroenterologist and molecular biologist at the Massachusetts General Hospital in Boston who was not involved in the work. “This suggests there may be correlates between the microbiota and changes in the host that can be identified in future experiments and exploited for therapeutic benefit.”

“This is a very nice work and it is bold—using high-fidelity shotgun metagenomics in an animal intervention model,” added Kristoffer Forslund a research scientist at the European Molecular Biology Laboratory, Heidelberg, Germany who was also not involved in the study. “Few have done that on this scale, which makes this a milestone.”

Lizard sex determination switching

PIXABAY, 7854Bearded dragons (Pogona vitticeps) typically become male or female on the basis of their chromosomes: animals carrying two copies of the male sex chromosome (ZZ) become male, while those carrying ZY become female. But about one-fifth of wild-caught female lizards have the male genotype (ZZ), according to a study published in Nature this week (July 1).

ZZ females, also known as sex-reversed females, are able to mate with ZZ males, producing twice as much offspring as ZY females. Moreover, the sex of those offspring is determined by the temperature at which the eggs were incubated. The findings suggest that the population may be transitioning from a chromosomal mode of sex determination to a thermal-based system.

“What this paper has shown is that that temperature override of the sex chromosomes actually does occur in the field,” Rick Shine, an evolutionary ecologist at the University of Sydney who reviewed the paper, told The Scientist. “There are lots of girls running around out there that are genetically male. . . . And it massively and instantaneously changes the sex-determining system in a local population.”

More news in life science:

Anti-Vax Doctor Found Dead

Police are calling the death of James Bradstreet, a physician who claimed vaccines cause autism and offered autism cures to patients, an apparent suicide.

Keeping Science Pubs Clean

Science releases new guidelines for research transparency, hoping to stem the tide of retractions and misconduct.

MERS Help on the Horizon?

New research finds that a treatment for Middle East respiratory syndrome can prevent and treat the disease in mice, while an experimental vaccine moves into human testing.

Police Sketches Via DNA

For assistance in solving crimes, a company has developed a service that will construct a face based on a genetic sample.

Morphine’s Missing Link Found

Researchers identified the last poppy gene product needed to produce morphine in yeast.