Worm surface chemistry reveals secrets to their development and survival
image:
Pristionchus pacificus precision predation. Adult P. pacificus wildtype predating on C. elegans wildtype larvae that are composed of unique surface chemistry as identified using 3D-OrbiSIMS
view moreCredit: University of Nottingham - Veered Chauhan
A new study has revealed the clearest-ever picture of the surface chemistry of worm species that provides groundbreaking insights into how animals interact with their environment and each other. These discoveries could pave the way for strategies to deepen our understanding of evolutionary adaptations, refine behavioural research, and ultimately overcome parasitic infections.
Scientists from the University’s School of Pharmacy used an advanced mass spectrometry imaging system to examine the nematodes Caenorhabditis elegans and Pristionchus pacificus, aiming to characterise species-specific surface chemical composition and its roles in physiology and behaviour. Their results show that nematode surfaces are predominantly oily or lipid-based, forming a complex chemical landscape. The findings have been published today in the journal JACS.
Nematodes, or worms, are found in nearly every environment on Earth, including inside animals, soil, plants, seeds, water, and even humans. Infections caused by nematodes can lead to serious health conditions in severe cases.
This research was led by Dr Veeren Chauhan, an Assistant Professor in Whole Organism Analytics at the School of Pharmacy, he explained: “Nematodes are an excellent model for human biology and are considered to be some of the most completely understood animals on the planet – especially in terms of genetics, neurology and developmental biology. We share around 60-70% of our DNA with these worms so any new discoveries about them can significantly enhance our understanding of human biology and can contribute towards solving global human health challenges.
Using world-leading mass spectrometry facilities, we studied the surface chemical properties of nematodes throughout their development. This allowed us to track molecular changes in detail and observe how surface chemistry differs during development, varies between species, and, importantly, influences their interactions with one another.”
The team used the state-of-the-art 3D-OrbiSIMS instrument at the University of Nottingham to reveal that the surface chemistry of both worm species change over time and they are made up of predominantly lipids, which account for approximately 70-80% of the molecular composition.
The University of Nottingham was one of the first institutions in the world to obtain a 3D-OrbiSIMS instrument. This instrument enables an unprecedented level of mass spectral molecular analysis across a range of materials, including hard and soft matter as well as biological cells and tissues. When the surface sensitivity, high mass resolution and spatial resolution, are combined with a depth profiling sputtering beam, the instrument becomes an extremely powerful tool for chemical analysis as demonstrated in this recent work.
Dr Chauhan continues: “Discovering that these worms have predominantly oily, or lipid-based, surface is a significant step in understanding their biology. These lipid surfaces help maintain hydration and provide a barrier against bacteria, which are essential for their survival. What is also very interesting is that these lipids also appear to serve as chemical cues that influence interspecies interactions, such as predation. For example, the predatory behaviour of Pristionchus pacificus is guided by physical contact with the surface lipids of its prey, Caenorhabditis elegans, and alterations in these lipids can increase the susceptibility of the prey to predation.”
Gaining this level of understanding of the surface chemistries of these worms and how they influence interaction and survival opens up new areas of scientific discovery and could ultimately help in developing strategies to fight parasitic worms and the diseases that they cause.”
This research was conducted in collaboration with the Lightfoot Lab, led by Dr James Lightfoot, at the Max Planck Institute for Neurobiology of Behavior – caesar in Bonn, Germany. This work was funded by a Nottingham Research Fellowship (University of Nottingham), the Engineering and Physical Sciences Research Council, the Max Planck Society, and by the German Research Foundation.
Journal
JACS
Method of Research
Imaging analysis
Subject of Research
Animals
Article Title
Surface lipids in nematodes are influenced by development and species-specific adaptations
Article Publication Date
12-Feb-2025
Worm study shows hyperactivated neurons cause aging-related behavioral decline
Nagoya University
image:
Head of the nematode C. elegans overlaid with red fluorescence of neurons
view moreCredit: Kentaro Noma
A study of nematodes by researchers at Nagoya University in Japan has found that aging-related decline in brain function is caused by the excessive activation of certain neurons over time, rather than a decline in neuronal activity. This finding, published in the journal Proceedings of the National Academy of Sciences, suggests that interventions aimed at reducing neuronal hyperactivation, such as dietary changes, could potentially mitigate age-related cognitive decline.
Proper brain function occurs when a large number of neurons are connected to each other and work in an appropriate way. In this sense, declines in brain function with age have generally been attributed to a decrease in the activity of neurons over time.
However, in humans, some types of neurons have been reported to become hyperactive with age. A research group led by Associate Professor Kentaro Noma of Nagoya University conducted experiments on nematodes to determine the cause-and-effect relations between the hyperactivation of neurons and the decline in brain function with age.
"In this study, we used the nematode Caenorhabditis elegans, which is only one millimeter long and has a lifespan of only two weeks. The nematodes exhibit a variety of behaviors with their 302 neurons," Noma said. "C. elegans shares many genes and mechanisms with humans. So, we thought that the cause of the decline in brain function over time in C. elegans may apply to humans."
This study took advantage of the ability of C. elegans to learn by association in a behavior called thermotaxis. In this behavior, C. elegans kept in an environment with food at 23 degrees Celsius will move toward 23 degrees when placed in an environment with a temperature gradient from 17 to 23 degrees. However, the animals will choose not to do so if kept in an environment where there is no food. This suggests that C. elegans learns to associate the presence or absence of food with the temperature of their environment.
"Our previous studies found that the brain function for associative learning in C. elegans declines over time, and we thought this was due to a decline in neuronal activity with age," said Binta Maria Aleogho, first author of the study. "In our latest study, however, we found that the activities of AFD sensory neurons and AIY interneurons, both of which are thought to be essential for associative learning, have barely changed with age."
The researchers then studied the behavior of C. elegans when each of six types of neurons thought to be involved in associative learning—the sensory neurons AWC and ASI, and the interneurons AIZ, AIB, RIA, and AIA—was removed from the brains of nematodes. Surprisingly, after removing AWC or AIA from their brains, the nematodes could move to the 23-degree location.
The researchers also measured the activities of the neurons in aged nematodes. They found that AWC and AIA are spontaneously and excessively activated with age. "This finding suggests that the hyperactivation of these two types of neurons with age disrupts the normal neuronal network, rendering them unable to carry out the thermotaxis behavior," Noma said.
"In addition, we were able to suppress neuronal hyperactivation and prevent behavioral decline in aged nematodes by changing the type of bacteria as their food source. So, we humans might be able to prevent the aging of our brains by changing our diet."
He concluded: "So far, we have tended to focus on the decline in neuronal activity with age. Our findings may lead people to focus on the hyperactivation of neurons. We will continue to study C. elegans to determine how to reduce the hyperactivation of neurons to improve brain function. We believe this will help us understand the basis of aging in brain function."
Schematic of the head of an aged C. elegans in which hyperactive neurons interfere with proper migration to the previous culture temperature
Credit
Kentaro Noma
Journal
Proceedings of the National Academy of Sciences
Method of Research
Experimental study
Article Title
Aberrant neuronal hyperactivation causes an age-dependent behavioral decline in Caenorhabditis elegans
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