Week in Review: September 7–11

New hominin species; cell-to-cell HIV transmission; mouth microbes predict dental caries; Lasker winners; transmissible amyloid-β?

Sep 11, 2015
Tracy Vence

New hominin

JOHN HAWKSResearchers described Homo naledi, a new species of ancient human that may have buried its dead, in two papers published in eLife this week (September 10). While the scientists have yet to date the fossilized bones of H. naledi, unearthed from a cave in South Africa, the team is convinced that its find “will be probably one of the best known hominin species discovered,” as study coauthor Lee Berger of University of the Witwatersrand in Johannesburg told The Scientist.

Carol Ward of the University of Missouri, who was not involved in the work, would like to see more data. “There’s nothing we can use to make our own judgments about the validity of what they are saying,” she said. And William Jungers threw water on the authors’ suggestion that H. naledi buried its dead in the cave where the fossils were found. “Dumping conspecifics down a hole may just be better than letting them decay around you,” said Jungers, who also was not involved in the work.

Intercellular HIV transmission

FLICKR; NIAIDHIV can be passed from one CD4+ T cell to the next, scientists from Gladstone Institute of Virology and Immunology and the University of California, San Francisco, and their colleagues published in Cell Reports last month (August 27). The findings could open up new avenues for research on how the virus depletes the immune system.

The results “could explain the progression of HIV to AIDS,” said Deborah Anderson, a microbiologist at Boston University School of Medicine who was not involved in the work.

Mouth microbes predict early-life caries

WIKIMEDIA, CDCShifts in the composition of the oral microbiome are predictive of a child’s risk of developing dental caries, researchers from the Chinese Academy of Sciences have shown. The results appeared in Cell Host & Microbe this week (September 9).

“We found that the change of microbiota occurred before the caries onset,” study leader Jian Xu told The Scientist. “When every tooth looked healthy to a professional dentist, the microbiota could predict future onset of caries.”

Flexible neuronal activity

NATHALIE DEHORTERScientists at King’s College London and their colleagues have found that certain mouse neurons perform different activities in different contexts. Fast-spiking (FS) parvalbumin-expressing (PV) basket cells fire differently depending on the expression of a specific transcription factor, the researchers showed in Science this week (September 10).

“It is very interesting that they’ve managed to find the causal link all the way from activity through a transcription factor, through the expression of a particular potassium channel, through to this electrophysiological phenotype,” said neurologist Dimitri Kullmann of University College London who was not involved in the research.

Transmissible amyloid-β?

FLICKR, ALLAN AJIFOStudying the brains of eight deceased patients who once received injections of growth hormone derived from the pituitary glands of cadavers, investigators from University College London and their colleagues found evidence to suggest that Alzheimer’s disease–associated amyloid-β could be transmissible. The team’s results were published in Nature this week (September 9).

“It’s the first in-human indication of potential transmission of amyloid-β pathology,” said Claudio Soto of the University of Texas Health Science Center in Houston who was not involved in the work.

But not all scientists are convinced. “This is such a small study with so many confounds that I am surprised it appears in Nature as it does not provide a clear and resounding answer on the question of human-to-human spread of pathological amyloid-β,” said John Trojanowski of the University of Pennsylvania who was not involved in the study.

Other news in life science:

Lasker Winners Announced
DNA-damage response and cancer immunotherapy discoveries are among those recognized by the Albert and Mary Lasker Foundation this year.

Using FOIA to Read Scientists’ Emails
Journalists and activists use the Freedom of Information Act to expose academics’ relationships with industry.

Tide Shifting on Embryo Gene Editing?
An international bioethics group says that research that involves editing genes in human embryos can be valuable, though it doesn’t approve of making “designer babies.”

Characterizing DNA Quadruplexes
Researchers are developing new techniques to better understand how and why knots of DNA are distributed throughout the genome.