In this bumper week for PLOS Biology, you can read about bat navigation, transmission of longevity, new neurons for old brains, how yeast anticipate change, a serious downside of illegal drug laws, and how to prioritise conservation efforts.
Why Do Bats Fly Differently in Light Versus Dark?
Bats are extremely skilful aviators that can manoeuvre accurately using either echolocation or vision. A model of animal flight guidance by Nadav Bar, Yossi Yovel & colleague suggests that bats use estimates of angular velocity and time-integrated sensory information to find their targets, and explains why bats fly straighter in the light than in the dark.
Yeast Longevity is Transmissible
Though calorie restriction has long been known to extend lifespan and healthspan in multiple model organisms, the intrinsic mechanisms remain unclear. In a new research paper by Szu-Chieh Mei & Charles Brenner, substances secreted by calorie-restricted yeast are found to induce longer life in other yeast cells, suggesting that intercellular communication is a component of this phenomenon, even in a single-celled organism.
Adult Neurogenesis: Are Humans like Rodents?
This new essay by Aurélie Ernst & Jonas Frisén discusses recent work on the birth of new neurons in the human adult brain, examining how it compares to that in other mammals. Although the rates of production of new neurons are the same, humans lack neurogenesis in the olfactory bulb, but show neurogenesis in the striatum. The authors explore the evolutionary changes that may have led to these differences and speculate about the function of adult neurogenesis in humans (particularly striatal neurogenesis), addressing the possibility of taking advantage of neurogenesis for therapeutic purposes (especially in disorders that can affect the striatum, such as Huntington’s disease, Parkinson’s, and stroke).
Strategies for Anticipating Change
Free-living microbes have a challenging existence, entirely beholden to the vagaries of their environment. However, two studies on the unicellular yeast Saccharomyces cerevisiae show that it is sometimes beneficial to anticipate change, and evolution can capitalise on this. Both studies – one by Jue Wang, Michael Springer and colleagues, and one by Ophelia Venturelli, Hana El-Samad and colleagues – look at the way in which yeast cope when faced with a mixture of sugars (imagine rotting fruit lying on the grass in an orchard), one of which is preferred over the other. The yeast consume the preferred sugar (glucose, say), but at some point must decide to make the costly switch to being able to metabolise the less preferred nutrient (galactose). The first paper shows that yeast turn on genes needed for galactose hours before the glucose runs out, but the degree of anticipation varies between wild strains, with each strategy subject to distinct trade-offs. The second paper shows that even within a population of genetically identical yeast, a subset of individuals gambles on change by activating genes pre-emptively.
Illegal Drugs Laws: Blocking Research for 50 Years
Did you know that heroine is a Schedule 2 drug, whereas cannabis is a Schedule 1 drug in the UK? In a passionate new Perspective, David Nutt describes how the laws on illegal drugs have stifled research and development of treatments for brain disorders for more than 50 years. Research on ‘illegal’ drugs before they were made illegal clearly showed therapeutic potential that has never been able to be realised. Here, the author makes concrete suggestions on how to clear these obstacles to research.
Conservation Priorities: Restoration? Protection? Both?
When it comes to habitat conservation, surely prevention is better than cure; we should protect forests as national parks rather than plant new trees, shouldn’t we? A new research article by Hugh Possingham, Michael Bode & Carissa Klein uses a modelling approach to address the question of when we should prioritise protection and restoration strategies. For their two case studies, they found that sometimes restoration is more cost-effective than habitat protection – dependent on the relative costs of the two actions, the rate of habitat loss and the time lag between restored habitat being as useful as intact habitat for securing species and ecosystem services.