The tapeworm dilemma
Instead of putting up with having to lug around a parasitic tapeworm that’s grown to one third of their body weight, some populations of the three-spined stickleback fish (Gasterosteus aculeatus) have evolved an interesting way to resist them – scarring.
But while some populations quickly evolved this immune defense – forming scar tissue around the tapeworm to stop its growth – other population tolerate them instead, scarring only a little or not at all. Until now, scientists haven’t understood why some stickleback populations evolved one way, and some another.
According to a new study in Science, scientists narrowed this adaptation down to a gene that is also closely associated with scarring in mice. But the authors say that there seems to be constant evolutionary pressure to tolerate tapeworms, instead of scarring them in, since female sticklebacks with lots of scarring are 80% less likely to successfully breed.
Spiralling stars in a stellar nursery
The combined power of NASA’s Hubble Space Telescope and the European Southern Observatory’s Very Large Telescope (VLT) has captured young stars spiralling into the centre of a massive cluster of stars in the Small Magellanic Cloud – a satellite galaxy of the Milky Way only 200,000 light-years away.
Astronomers think that the spiral may be feeding star formation in the huge, oddly shaped stellar nursery called NGC 346 within the galaxy.
“A spiral is really the good, natural way to feed star formation from the outside toward the center of the cluster,” explains co-author Dr Peter Zeidler, of the Space Telescope Science Institute (STScI) for the European Space Agency, US. “It’s the most efficient way that stars and gas fuelling more star formation can move towards the centre.”
The Small Magellanic Cloud has a simpler chemical composition than the Milky Way, so it’s more similar to the galaxies found in the younger universe when heavier elements were scarcer. These findings give scientists further insight into how star formation may have occurred early in the universe’s history.
The new study has been published in The Astrophysical Journal.
How memory of personal interactions declines with age
Being unable to remember the face that goes along with the name of the person you talked to, just hours earlier, is one of the most upsetting aspects of typical age-related memory decline. Scientists still don’t understand exactly why this occurs, but a new study published in Aging Cell provides some important new clues.
Researchers have identified a potential target for developing new therapies to treat age-related cognitive decline by studying ageing mice, discovering that levels of an enzyme called PDE11A increased with age. Specifically, it increased in the hippocampus – a brain region responsible for many types of learning and memory – as little filaments in compartments of neurons.
When the PDE11A gene was deleted, cognitive decline in older mice no longer occurred. But when PDE11A was added back into the hippocampus of these old mice, they once again forgot social associative memories.
“PDE11 is involved in more things that just memory, including preferences for who you prefer to be around. So, if we are to develop a therapy to help with cognitive decline, we would not want to get rid of it entirely or it could cause other negative side effects,” explains senior author Michy Kelly, associate professor of Anatomy and Neurobiology at the University of Maryland School of Medicine, US.
Walking for multi-legged creatures is a lot like slithering
Apparently, the physics of walking is simpler than we thought, according to a new study in the Proceedings of the National Academy of Sciences.
By studying several colonies of Argentine ants and multi-legged robots using a computer algorithm, researchers have found that walking (for many-legged creatures) is actually a lot like slithering. They discovered a new mathematical relationship between walking, skipping, slithering, and swimming in viscous fluids, for multi-legged animals and robots.
“This is important because it will allow roboticists to build much simpler models to describe the way robots walk and move through the world,” explains co-author Nick Gravish, assistant professor in the Department of Mechanical and Aerospace Engineering at the University of California San Diego.
The researchers also hypothesise that these universal principles may have implications for understanding major evolutionary transitions, for example from swimming to walking.
Adding fungal enzymes to cow feed boosts milk production
Supplementing dairy cattle feed with the enzymes from two different funguses – Aspergillus oryzae and Aspergillus niger – positively effects their lactation performance, according to new research in the Journal of Dairy Science.
When compared with the control group, cows which were fed the enzymes tended to eat more, and their milk had higher concentrations of protein, lactose and other desirable solids. Overall, enzyme consumption seemed to have a notably positive effect on milk quantity and quality.
The enzymes seem to have an effect in the cow’s rumen (their four-chambered stomach), promoting the activity of the microbial populations that enhance the digestion of fibre from their diets.
“We are trying to help the rumen microbes do what they do,” explains co-author Alex Hristov, distinguished professor of Dairy Nutrition at Penn State University in the US. “The microbes produce these enzymes that break down fibre, but we are trying to supplement additional enzymes to enhance fermentation in the rumen.”
These findings are important because developing strategies to enhance the performance of dairy cows while reducing feeding costs is critical for feeding a growing world population.
Women’s Health Week
Last week was Jean Hailes’ Women’s Health Week, an Australia-wide campaign of events and online activities centred on improving women’s health and helping women, girls and gender diverse people to put good health first.