Week in Review: July 18–22

Organoids versus animal models; mapping the human cortex; how hyperglycemia affects the brain; delivering drugs to tumors with engineered bacteria; neurons compete for memory space 

Tracy Vence
Jul 22, 2016

Model organoids

Scientists are developing increasingly sophisticated in vitro mini organs, some that can even model human physiology. But these are unlikely to fully replace in vivo testing on animal models. Still, these organoids may supplant animal models for toxicology testing and similar applications.

“Organoids are a fantastic new tool to do research,” Denis Duboule of the École Polytechnique Fédérale de Lausanne in Switzerland told The Scientist. But when it comes to animal models, “I don’t see it as a replacement,” he said.

More-complete cortical map

Researchers from Washington University School of Medicine in St. Louis have produced the most complete map of the human cortex to date, pinpointing 97 regions of this part of the brain previously unknown to neuroscience.

Hyperglycemia and the brain

Studies on zebrafish and humans are beginning to highlight how persistent elevated blood sugar is linked to cognitive deficits.

Neuronal competition

Brain cells compete with one another for space in memory-storing groups called engrams. Scientists at the Hospital for Sick Children in Toronto have now shown that, in mice, engrams formed closer in time to one another are more likely to be linked.

Cancer drug delivery

Scientists at the University of California, San Diego, have engineered a strain of Salmonella enterica that self-destructs only after delivering an anti-tumor toxin in a mass of cancer cells in mice.

“This impressive study represents a big step towards one of the great dreams of synthetic biology: rationally programming cells, in this case bacteria, to exhibit complex, dynamic, and beneficial behaviors in a host organism,” said Michael Elowitz of Caltech who was not involved in the work.

Microbe-primate co-evolution

A team led by investigators at the University of Texas at Austin has reported evidence to suggest that certain gut bacterial species diverged along with hominid lineages.

“This paper sets the stage for the possibility that our mutualistic gut bacteria evolved at the same rate as hominids, which, to me, suggests that this mutualistic symbiosis helped the human species evolve,” said Julie Segre of the National Human Genome Research Institute who was not involved in the study but penned an accompanying perspective.

Already approved

Another already-approved drug has shown anti-Zika activity in vitro. Two months ago, researchers at the Federal University of Rio de Janeiro showed that the antimalarial drug chloroquine reduced Zika virus infection of human cells in a dish. Now, scientists at the Rio-based Oswaldo Cruz Foundation have shown that sofosbuvir, a drug approved for the treatment of hepatitis C, has similar effects on human and animal cells.

“I do believe this provides the basis to do additional testing with this compound,” said Matthew Aliota of the University of Wisconsin who was not involved in the work—“preferably in an animal model.”

Other news in life science

Unexplained Zika Case in Utah
Health officials are investigating a case of Zika infection in a patient who acquired the virus while caring for an infected relative who died this month.

Report: Biodiversity Has Fallen Below “Safe” Levels
More than half of the world’s land may have passed the threshold that threatens long-term sustainable development, researchers report.

Lab Legos
3-D printed components allow researchers to construct custom-made instruments.