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Comment by Dr. Krishna Kumari Challa on Wednesday

Can animals count? Neuroscientists identify a sense of numeracy among rodents

A discovery that appears to confirm the existence of discrete number sense in rats has been announced by a joint research team from City University of Hong Kong (CityUHK) and The Chinese University of Hong Kong (CUHK).

The findings offer a crucial animal model for investigating the neural basis of numerical ability and disability in humans, the Hong Kong-based researchers say.

This innovative study deployed a numerical learning task, brain manipulation techniques and AI modeling to tackle an ongoing debate about whether rats can count.

Their study, published in Science Advances, sheds light on the mechanisms underlying numerical ability, a cognitive ability fundamental to mathematical aptitude, which is a hallmark of human intelligence. The article is titled "Disparate processing of numerosity and associated continuous magnit...".

The team found that rats without any previous knowledge of numbers could develop a sense of numbers when trained with sounds representing two or three numbers. Despite the influence of continuous magnitudes, the rats consistently focused on the number of sounds when making choices for food rewards.

In addition, the study helps dissect the relationship between magnitude and numerosity processing.

The researchers discovered that when they blocked a specific part of the rats' brains, called the posterior parietal cortex, the rats' ability to understand numbers was affected but not their sense of magnitude. "This suggests that the brain has a specific area for dealing with numbers".

The study not only solves a long-standing mystery about how brains handle numbers but also offers new insights into studying the specific neural circuits involved in number processing in animals and how genes are associated with mathematical ability. The findings from neural network modeling could have practical applications in the field of AI.

Tuo Liang et al, Disparate processing of numerosity and associated continuous magnitudes in rats, Science Advances (2024). DOI: 10.1126/sciadv.adj2566

Comment by Dr. Krishna Kumari Challa on Wednesday

In search for alien life, purple may be the new green

From house plants and gardens to fields and forests, green is the color we most associate with surface life on Earth, where conditions favored the evolution of organisms that perform oxygen-producing photosynthesis using the green pigment chlorophyll a.

But an Earth-like planet orbiting another star might look very different, potentially covered by bacteria that receive little or no visible light or oxygen, as in some environments on Earth, and instead use invisible infrared radiation to power photosynthesis.

Instead of green, many such bacteria on Earth contain purple pigments, and purple worlds on which they are dominant would produce a distinctive "light fingerprint" detectable by next-generation ground- and space-based telescopes, scientists report in new research.

Purple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds.

This is the gist of the paper titled "Purple is the New Green: Biopigments and Spectra of Earth-like Purple Worlds," published in Monthly Notices of the Royal Astronomical Society.

So we need to create a database for signs of life to make sure our telescopes don't miss life if it happens not to look exactly like what we encounter around us every day, the researchers say.

Purple bacteria can survive and thrive under such a variety of conditions that it is easy to imagine that on many different worlds, purple may just be the new green.

Lígia Fonseca Coelho et al, Purple is the new green: biopigments and spectra of Earth-like purple worlds, Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae601

Comment by Dr. Krishna Kumari Challa on Wednesday

The researchers think that the pilus motors not only serve as mechanical actuators but also as sensors. This means that they can detect mechanical stimuli in the environment in the environment, which allows for synchronized movements within bacterial populations.

Shiqi Liu et al, Emergence of large-scale mechanical spiral waves in bacterial living matter, Nature Physics (2024). DOI: 10.1038/s41567-024-02457-5

Part 4

Comment by Dr. Krishna Kumari Challa on Wednesday

The findings shed light on bacterial populations and behavior, such as the formation of biofilms.

When bacteria adhere to a surface, it does so by producing extracellular polymeric substances (EPS). This substance forms a structured community known as biofilm, such that the bacteria is embedded in a matrix of EPS, protecting the bacteria from environmental stresses like antibiotics and host immune responses.

This entire process, known as the formation of biofilms, is essential for the survival of bacterial colonies. The opposite of this phenomenon—dispersal—is equally important.

When bacteria within a biofilm detach and spread to new locations, it is known as dispersal. Dispersal can occur in response to environmental cues, nutrient availability, or as part of the life cycle of the bacteria.

This mechanism can help bacteria colonize new surfaces or host environments and can influence the spread of infectious diseases or the formation of microbial communities in various ecosystems.

Part 3

Comment by Dr. Krishna Kumari Challa on Wednesday

These spiral waves as observed by the researchers in bacteria are an emergent phenomenon. Emergent phenomena are a crucial aspect of complex systems, which are systems where the interaction of individual entities leads to phenomena that otherwise can't be observed.

This means we need to understand what is happening at the level of each entity, which in this case is a Pseudomonas aeruginosa bacterium. These bacteria have pilus motors, which are the key to the spiral waves.

Pilus motors are molecular motors, which are attached to pili—thin, hair-like appendages present on the bacterial cell surface. These motors play an important role in various processes for the bacterium, such as movement and surface attachment.

The propagating spiral waves resulted from the coordinated activity of the pilus motor, a grappling-hook-like motile organelle found in many bacterial species.

The mechanical movements of the pilus motors in many bacteria result in these spiral waves, which are like ripples on the bacterial surface.

The researchers found that the spiral waves resulted from the coordinated activity of pilus motors. They also observed that the waves were self-sustaining and stable, with nearly stationary spiral cores.

This stability is a characteristic shared by certain types of electrical and chemical spiral waves found in other living systems. However, the spiral waves observed in the bacteria are distinct from the other spiral waves.

Part 2

Comment by Dr. Krishna Kumari Challa on Wednesday

Scientists observe mechanical waves in bacterial communities

A new study by researchers  has reported the emergence of mechanical spiral waves in bacterial matter.

Spiral waves are commonly seen in artificial and natural systems (such as the heart). These emerge from interactions of neighboring elements, such as cardiac cells in the case of the heart. These spiral waves can have varying effects, sometimes leading to life-threatening conditions like fibrillation in the heart.

The new study, published in Nature Physics, explores spiral waves in bacteria—something that has not been observed before. In particular, the researchers' focus was on the species Pseudomonas aeruginosa. These are commonly found in soil and water and are also known to colonize hospitals.

The research is a continuation of their previous work where the authors studied long-range material transport in bacterial communities via open fluid channels.

Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

In this new study, scientists  used both single-cell and single-nucleus sequencing techniques along with advanced imaging to analyze human muscle samples from 17 individuals aged 20 to 75.

They discovered that genes controlling ribosomes, responsible for producing proteins, were less active in muscle stem cells from aged samples. This impairs the cells' ability to repair and regenerate muscle fibers as we age. Further, non-muscle cell populations within these skeletal muscle samples produced more of a pro-inflammatory molecule called CCL2, attracting immune cells to the muscle and exacerbating age-related muscle deterioration.

Age-related loss of a specific fast-twitch muscle fiber subtype, key for explosive muscle performance, was also observed. However, they discovered for the first time several compensatory mechanisms from the muscles appearing to make up for the loss. These included a shift in slow-twitch muscle fibers to express genes characteristic of the lost fast-twitch subtype, and increased regeneration of remaining fast-twitch fiber subtypes.

The researchers  also identified specialized nuclei populations within the muscle fibers that help rebuild the connections between nerves and muscles that decline with age. Knockout experiments in lab-grown human muscle cells by the team confirmed the importance of these nuclei in maintaining muscle function.

With these new insights into healthy skeletal muscle aging, researchers all over the world can now explore ways to combat inflammation, boost muscle regeneration, preserve nerve connectivity, and more. Discoveries from research like this have huge potential for developing therapeutic strategies that promote healthier aging for future generations.

 Human skeletal muscle aging atlas, Nature Aging (2024). DOI: 10.1038/s43587-024-00613-3

Part 2

Comment by Dr. Krishna Kumari Challa on Tuesday

Human muscle map reveals how we try to fight effects of aging at cellular and molecular levels

How muscle changes with aging and tries to fight its effects is now better understood at the cellular and molecular level with the first comprehensive atlas of aging muscles in humans.

Researchers applied single-cell technologies and advanced imaging to analyze human skeletal muscle samples from 17 individuals across the adult lifespan. By comparing the results, they shed new light on the many complex processes underlying age-related muscle changes.

The atlas, published April 15 in Nature Aging, uncovers new cell populations that may explain why some muscle fibres age faster than others. It also identifies compensatory mechanisms the muscles employ to combat aging.

The findings offer avenues for future therapies and interventions to improve muscle health and quality of life as we age.

This study is part of the international Human Cell Atlas initiative to map every cell type in the human body, to transform understanding of health and disease.

As we age, our muscles progressively weaken. This can affect our ability to perform everyday activities like standing up and walking. For some people, muscle loss worsens, leading to falls, immobility, a loss of autonomy and a condition called sarcopenia. The reasons why our muscles weaken over time have remained poorly understood till now.

Part 1

Comment by Dr. Krishna Kumari Challa on Tuesday

Evolution's recipe book: How 'copy paste' errors led to insect flight, octopus camouflage and human cognition

Seven hundred million years ago, a remarkable creature emerged for the first time. Though it may not have been much to look at by today's standards, the animal had a front and a back, a top and a bottom. This was a groundbreaking adaptation at the time, and one which laid down the basic body plan which most complex animals, including humans, would eventually inherit.

The inconspicuous animal resided in the ancient seas of Earth, likely crawling along the seafloor. This was the last common ancestor of bilaterians, a vast supergroup of animals including vertebrates (fish, amphibians, reptiles, birds, and mammals), and invertebrates (insects, arthropods, mollusks, worms, echinoderms and many more).

To this day, more than 7,000 groups of genes can be traced back to the last common ancestor of bilaterians, according to a study of 20 different bilaterian species including humans, sharks, mayflies, centipedes and octopuses. The findings were made by researchers at the Centre for Genomic Regulation (CRG) in Barcelona and are published today in the journal Nature Ecology & Evolution.

Remarkably, the study found that around half of these ancestral genes have since been repurposed by animals for use in specific parts of the body, particularly in the brain and reproductive tissues. The findings are surprising because ancient, conserved genes usually have fundamental, important jobs that are needed in many parts of the body.

When the researchers took a closer look, they found a series of serendipitous "copy paste" errors during bilaterian evolution were to blame. For example, there was a significant moment early in the history of vertebrates. A bunch of tissue-specific genes first appeared coinciding with two whole genome duplication events.

Animals could keep one copy for fundamental functions, while the second copy could be used as raw material for evolutionary innovation. Events like these, at varying degrees of scale, occurred constantly throughout the bilaterian evolutionary tree.

The authors of the study found many examples of new, tissue-specific functions made possible by the specialization of these ancestral genes.

The specialization of ancestral genes also laid some foundations for the development of complex nervous systems

Evolution of tissue-specific expression of ancestral genes across vertebrates and insects, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02398-5

Comment by Dr. Krishna Kumari Challa on Tuesday

The study also found that different bird species have different impacts in terms of seed dispersal. Smaller birds disperse more seeds, but they can only spread small seeds from trees with lower carbon storage potential. In contrast, larger birds such as the Toco toucan or the Curl-crested jay disperse the seeds of trees with a higher carbon storage potential. The problem is that the larger birds are less likely to move across highly fragmented landscapes.
This crucial information enables us to pinpoint active restoration efforts—like tree planting—in landscapes falling below this forest cover threshold, where assisted restoration is most urgent and effective.
Allowing larger frugivores to move freely across forest landscapes is critical for healthy tropical forest recovery.
This study demonstrates that especially in tropical ecosystems seed dispersal mediated by birds, plays a fundamental role in determining the species that can regenerate.

Frugivores enhance potential carbon recovery in fragmented landscapes, Nature Climate Change (2024). DOI: 10.1038/s41558-024-01989-1

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