Week in Review: October 21–25

Latent HIV more potent than once thought

FLICKR, NIAIDKnowing the size of the latent reservoir (LR)—the amount of dormant DNA able to make functional virus—is essential for designing anti-HIV therapies. According to the results of PCR-based tests published in Cell this week (October 24), the HIV LR persisting in CD4⁺ T cells is potentially 60 times larger than previously believed.

“I think everybody in the field had a sense that there was something like this to explain the discrepancy between the VOA [viral outgrowth assay] and the PCR-based assay,” the University of Maryland School of Medicine’s Fabio Romerio told The Scientist. “What was really striking, at least to me, was that there is a high frequency of cells that do not produce virus when they are cultured in the VOA, and yet they contain replication-competent HIV sequences,” continued Romerio, who was not involved in the work. “That is scary.”

David Margolis, a professor of medicine at the University of North Carolina, Chapel Hill, who studies HIV latency but was not part of the work, added: “None of the data is really surprising, but it’s really important that it’s definitively shown.”

Genome-microbiome connection

FLICKR, NIAIDA team led by investigators at University of Minnesota has identified correlations between the composition of the human microbiome and genetic variation in immune-related pathways.

“The biggest result we have is a lot of these pathways are involved in immunity,” said study leader Ran Blekhman. “[It seems that] host genetic variation and immunity-related pathways and genes could maybe control the structure of the microbiome.”

Blekhman and his colleagues analyzed the genomes and body-wide microbial communities of 93 people, finding a link between the composition of the microbiome and genetic variation in innate immunity, phagocyte function, and other immune pathways.

“This study is the one of the first documenting the relationship between microbiome composition and the human genome,” the National Human Genome Research Institute’s Lita Proctor, who was not involved in the work, told The Scientist in an e-mail.

Rapamycin extends flu vaccine’s reach

WIKIPEDIA, ANYPODETOSScientists from St. Jude Children’s Research Hospital have found that the immunosuppressant drug rapamycin helped to protect mice against a diverse range of influenza viruses after the rodents were vaccinated against just one strain. Writing in Nature Immunology, Rachael Keating and her colleagues showed that mice administered a dose of the drug while being immunized against a strain of seasonal H3N2 flu could also thwart infections from doses of H1N1, H5N1, and H7N9.

Although the mouse work showed promise, “we’re definitely not advocating that we use rapamycin [in humans],” said study coauthor Maureen McGargill.

No pain, plus gain

COURTESY OF MATTHEW AND ASHLEE ROWEThough it produces a toxic, pain-inducing venom that deters most predators, the Arizona bark scorpion is not safe from grasshopper mice. Thanks to mutations in a pain-transmitting sodium channel, grasshopper mice can prey on the bark scorpions without experiencing the venom’s intended effects. In a paper published this week (October 24) in Science, Michigan State University’s Ashlee Rowe and her colleagues showed that amino acid changes in the Nav1.8 channel allow the rodents to feast on their toxic prey.

Thomas Park of the University of Illinois at Chicago had previously observed a similar phenomenon in the naked mole-rat. “Instead of trying to stop the receptors from doing their job, they simply stopped the nerve cells from being able to transmit the signal,” Park told The Scientist. “[It is] really super cool . . . that two remarkably distantly related mammals would target the same strategy for disabling a specific kind of pain.”.

Other news in life science:

Ancient Bee Die Out
Researchers show that one group of bees likely suffered a mass extinction about 65 million years ago.

Company Size Won’t Predict Success
New analysis finds that the size of a company is not tied to getting a drug to market.

Confirmed Venomous Crustacean
Researchers show that a cave-dwelling crustacean may use venom to immobilize and digest its prey.

Lab-Grown Hair Follicles
Using molecular signatures of human dermal papilla cells grown in a 3-D environment, researchers generate new hair follicles using a patient’s own cells.

Brain-Washing During Sleep
Rest clears out interstitial clutter in the mouse brain.