Interesting science news from around the world. This month, we discover how poor eyesight may be a risk factor for dementia, how the largest moon in our solar system was shaped by an asteroid collision, and how an ancient rock bridge allowed scientists to date when humans arrived on a Mediterranean island for the first time.
BY DR. EVA HAMRUD: I am a bioinformatician with a primary research interest in stem cell biology. I am also passionate about all areas of scientific research and their communication.
PHYSICS
Common food coloring makes mouse tissue transparent
Most animal tissue is opaque, which means that many medical research questions require that laboratory animals such as mice are dissected to explore what is happening below the skin. Dissection cannot be performed on living animals, and it is also costly. Researchers at Stanford University have published an alternative approach in which mouse tissue was made temporarily transparent. By rubbing a chemical onto the abdomen, head or leg of a live mouse, the researchers were able to get videos and images of the mouse’s working digestive system, cerebral blood vessels and muscle cells.
Surprisingly, the chemical used to create this transparency is a simple dye, specifically a common yellow food colouring called tartrazine. Tartrazine makes tissue transparent because it makes the tissue absorb light of one colour very strongly, which modifies the tissue’s refractive index. Biological tissue is opaque because different components (skin, muscle, fat) have different refractive indices, that is they bend light in different ways, and this means light is scattered. By adding the yellow food colouring to the tissue, the different components absorb light in a more similar way, so their refractive indices become more similar and they become transparent. As tartrazine is safe to use on living mice and is reversible, when it is washed off the mouse becomes opaque again, it offers a new way for biologists to study the inner workings of living animals non-invasively.
🧬Why is biological tissue opaque? 🧪What is tartrazine? 🧬What is refractive index?
ARTIFICIAL INTELLIGENCE
Is ‘AI scientist’ a step towards automating research?
A preprint research paper posted this month describes ‘AI Scientist’ a large language model that can perform all parts of the science life cycle, from ‘reading’ papers, running ‘experiments’ and even producing and self-evaluating a paper. ‘AI Scientist’ joins a group of AI programs that have been created to automate parts of the research process. So far, these AI programs have not been groundbreaking, for example ‘AI Scientist’ is only limited to researching machine learning and its outputs suggest only incremental advancements on what we already know. Some critics of these AI algorithms claim that scientific research requires human-level communication and creativity which cannot be performed by AI alone, however, it is likely that AI will begin to be used for the more repetitive and time-consuming aspects of research.
🤖How could AI speed up scientific research? 🤖Is AI good at scientific research?
MEDICINE
Poor eyesight linked to dementia
Around 55 million people currently live with dementia, and this number is projected to rise as a result of ageing populations. Dementia describes a collection of symptoms that include memory loss and reduction in cognitive function. Currently, no treatment exists to reverse the effects of dementia once symptoms have started, however researchers are focused on identifying risk factors which are associated with dementia. By modifying these factors, it is possible to reduce the risk of developing dementia.
What are the risk factors for dementia?
There are many well-documented risk factors for dementia, and many of these are summarised by the Lancet Commission report on dementia released this year. This report includes midlife risk factors such as depression, hearing loss, physical inactivity and obesity, and late life risk factors such as social isolation, air pollution, and visual loss. Most recently, a study published in the journal of JAMA Ophthalmology found that almost one fifth of dementia cases could be linked to eyesight problems. The authors of the study used data from over 2,700 adults in the US over the age of 65 to look at the relationship between dementia and different types of visual impairment including short sightedness.
How might eyesight be connected to dementia?
It is not yet known how eyesight may be connected to dementia. One possibility is that visual impairment feeds into other known risk factors such as social isolation and sensory deprivation, alternatively there could be a common mechanism behind eyesight problems and dementia. Although there is not a proven causative relationship between eyesight and dementia, regular optometrist visits are recommended as many of the most common visual impairments can be prevented and treated.
📚What is dementia? 📖How can dementia be prevented?
ASTRONOMY
Jupiter’s moon was hit by a giant asteroid
Jupiter, the largest planet in our solar system, is orbited by at least 95 moons. Its largest moon, Ganymede, is also the largest moon in the solar system and is even bigger than the planet Mercury. By examining the topographic profiles of Ganymede and running computer simulations, scientists at Kobe University in Japan have suggested that this moon was hit by a giant asteroid around 4 billion years ago. The asteroid is thought to have been several times larger than the meteor which wiped out the dinosaurs on earth. The asteroid’s collision appears to have significantly shaped Ganymede today, including distinctive furrows on the moon’s surface and its tilted rotational axis. This finding is another step closer to recreating the early solar system and events that shaped what the planets and moons look like today.
🪐How was Jupiter and its moons formed? ☄️What are asteroids?
ANTHROPOLOGY
Prehistoric bridge indicates when humans first traveled to Mallorca
Homo sapiens originated in Africa around 300,000 years ago and then migrated into Asia and from there the rest of the world. Typically, carbon dating of human remains or tools and pottery are used to indicate when ancient humans arrived in a location. In Mallorca, one of the largest islands in the Mediterranean Sea, dated materials suggest that people arrived around 4,400 years ago, making it one of the last Mediterranean islands to be reached by humans. A new study published in Nature Communications Earth & Environment used a different method to identify this date: a prehistoric bridge. This bridge, which is around 9 metres long and made of stone, is located in the Genovesa Cave and is now completely submerged in water. However, by using encrustations of minerals on stalagmites and stalactites, the researchers were able to identify what the sea level was thousands of years ago. By using the height of the stone bridge and colouration on its surface which indicates what the water level would have been when it was built, the authors of the study found that humans reached Mallorca 1,000 years before previous estimates. This study highlights how alternative approaches can be used to help us further our understanding of prehistoric humans.
📖Tell me about the origin of homo sapiens 🐵How do we study prehistoric humans? 🌊How can past sea levels be estimated in caves?
NATURE ODDITIES
Ancient fish
Fossils of the ancient fish Pegasus volans were first discovered over 200 years ago in northern Italy, however scientists are still undecided on where the animal lies on the tree of life. The animal, which may have lived around 50 million years ago, was less than 6 centimetres long and extremely thin, with boomerang-like fins extending from its body. The creature’s Latin name places it in the genus Pegasus along with seamoths, which are fish with flattened bodies and long snouts. A detailed characterisation of the species’s fossils released as a preprint at the end of last month suggests that the ancient fish should not be grouped with seamoths, however the authors were not able to place the fish in an alternative genus. Potentially more fossil evidence will help to decipher where this fish could be grouped, particularly as current fossils do not include the tail of the fish.
🐄How are animals placed on the tree of life? 🦟How are ancient animals studied?
CONSENSUS ANSWER OF THE MONTH
How did life begin?
The origin of life on Earth is believed to have occurred between 4.6 and 3.8 billion years ago, under specific environmental conditions that allowed for the accumulation of liquid water and organic polymers. While traditional theories focused on a “primordial soup,” recent evidence suggests life may have begun in more extreme environments, such as deep-sea vents or even on Mars. The role of RNA in early catalysis and replication is considered crucial in the transition from chemical to biological evolution. Despite significant progress, the exact pathways and mechanisms remain a subject of ongoing research and debate.
⚛️How did life begin?REFERENCES
Transparent mouse skin
Science research article
Nature news article
AI Scientist
Arxiv preprint research article
Nature news article
Dementia and eyesight
JAMA ophthalmology research article
The Lancet risk factors for dementia
Guardian news article
Jupiter moon
Scientific reports research article
Live science news article
Guardian news article
Prehistoric bridge
Nature communications Earth & Environment research article
Nature video and news article
Ancient fish
Preprint research article
ScienceNews news article