#16 Artificial Organic Neurons, The Secret of Fungi and Awaking Zombies...
How biological systems can be steered by Artificial Organic Neurons, a key fungi in nature - Mycorrhizal, and how some gut microbes are awaking zombie viruses...
🧠Biology Steered By Artificial Organic Neurons…
How Biological Systems Can Be Steered by Artificial Organic Neurons
Neurons are fundamental constituents of the brain and nervous system. They are the cells responsible for receiving sensory input and for the first time researchers have demonstrated an artificial organic neuron that can be integrated within a living plant. The integrated neuron as well as the functioning synapse have been made from printed organic electrochemical transistors.
The research team used a Venus flytrap to demonstrate this artificial nerve and synapse as this organism clearly shows how the biological system has been steered and influenced by the artificial organic system. The electrical pulses from the artificial nerve can cause the leaves to close, however so far, no fly has entered the trap. The fundamental reason that this printed system works is due to the fact that the organic semiconductors can conduct both electrons and ions and so mimicking the ion-based mechanism (action potential) generation in plants.
In 2018 the research group became the first to develop complementary and printable organic electrochemical circuits, this includes those which conduct both negative and positive charges. This allowed the team to print complementary organic electrochemical transistors. Together with other collaborators the team has printed transistors that emulate biological neurons and synapses.
“For the first time, we’re using the transistor’s ability to switch based on ion concentration to modulate the spiking frequency” - Padinhare Cholakkal Harikesh, post-doctoral researcher at the Laboratory of Organic Electronics. This spiking frequency is what gives the signal that causes the biological system to react.
Furthermore the team has shown how the connection between the neuron and the synapse has a learning behaviour, termed Hebbian learning. Information is stored in the synapse which makes the signalling more effective. The hope is that in time, the artificial nerve cells can be used for sensitive human prostheses, for implantable systems that relieve neurological diseases and soft intelligent robotics.
"We've developed ion-based neurons, similar to our own, that can be connected to biological systems. Organic semiconductors have numerous advantages – they're biocompatible, biodegradable, soft and formable. They only require low voltage to operate, which is completely harmless to both plants and vertebrates" explains Chi-Yuan Yang, post-doctoral researcher at the Laboratory of Organic Electronics.
🍄The Secret of Fungi…
The Secret of Mycorrhizal Fungi and its Role in Nature
Mycorrhizal fungi are critical members of the plant microbiome, forming a symbiosis with the roots of almost every plant on earth, as a result they are natural allies of the forest, key in improving tree nutrient acquisition. But which of the mycorrhizal feeding strategies yields the greatest tree diversity? Strategy A - Ectomycorrhiza or Strategy B - Arbuscular mycorrhiza. A team of biologists from the University of Montreal with the Plant Biology Research Institution found that a combination of the two is most beneficial.
This positive association for between a plant and a fungus is the most widespread and important form of mutualistic symbiosis in terrestrial ecosystems.
The mycorrhizal fungi have long been known to provide plants with significant nutritional benefits. This mainly occurs due to the fungi extending the root system by up to 10 times the initial root surface and enabling better absorption of water and minerals from the soil. The fungi, able to dissolve phosphorus in the soil, is provided with sugar produced by the plant through photosynthesis - a perfect example of a symbiotic and mutualistic biological relationship.
For some time there has been growing interest in the relationship and its link with plant species diversity. The two main types, ectomycorrhizas and arbuscular mycorrhizas, seem to influence the diversity in numerous ways.
The Ectomycorrhiza affects roughly 2% of plant species, being most prominent in Northern Hemisphere forests. The Arbuscular mycorrhiza are the oldest and most widespread form of symbiotic association between fungi and plants, they are largely more influential, affecting 80% of terrestrial plants. The main way in which the two types differ from each other is the way in which they attach to the root of the plant. As a result scientists have observed that forests colonized by the arbuscular mycorrhiza are more diverse (E.g. Rainforests).
Scientists have often believed that arbuscular mycorrhiza promotes coexistence whereas the ectomycorrhiza promotes dominance in just one or two species. However this new study challenges the hypothesis.
Forest trees and mycorrhizal fungi interact at a very local level over a period of decades. Carteron, a Ph.D. in Biology from the University stated that "We analyzed about 82,000 forest plots across the United States and concluded that plots that were very strongly dominated by either ectomycorrhiza or arbuscular mycorrhiza had lower tree diversity," "Surprisingly, it was the forests with a mix of both mycorrhizal strategies that had a greater number of tree species. So our results indicate that dominance of any one mycorrhiza, regardless of its type, appears to decrease forest tree diversity."
The study demonstrates the importance of mycorrhizal fungi and how the coexistence is integral to plant diversity. Knock on effects to this interaction can be highly influential in the climate and potentially key in the fight against climate change. "Sometimes forests with a mixture of mycorrhizal strategies are overlooked by biologists because they're considered less abundant," the researchers said. "However, our study has shown that this is not always the case and these mixed types could, in fact, make up a large part of the world's forests." These forests could be a crucial research area and target for climate change.
🧟Gut Microbes Awaken Zombies
How Some Gut Microbes Awaken Zombie Viruses in Neighbours…
The gut microbiota is hugely important in helping control digestion and in aiding the immune system, as well as many other functions. Some gut bacteria have a super power - awaking viruses from death. Through animating otherwise dormant viruses, lurking within other microbes, the full blown infections that destroy virus carrying cells is unleashed. The Howard Hughes Medical Institute Investigator Emily Balskus’s lab found a cryptic molecule called colibactin that can summon the killer viruses from their slumber.
Microbes often attack one another, often generating noxious compounds in the cramped battlegrounds of the gut. Within these chemicals is colibactin, which appeared unusual to the research team. "It doesn't directly kill the target organisms, which is what we normally think of bacterial toxins doing within microbial communities." Rather than a direct approach, colibactin tweaks microbial cells, activating latent and lethal viruses’ that are hidden away in some bacteria’s genome. Humans have long sought out the potent compounds that microbes produce. "We know a lot about their chemical properties, we purify them in the lab, and we use them as medicine, including antibiotics," says Breck Duerkop, who studies bacterial viruses at the University of Colorado School of Medicine.
Scientists have known for years that colibactin can wreak havoc. Researchers as well as others have shown that the compound damages DNA which can lead to colorectal cancer. Dubbed colibactin in 2006, a French research team linked damage of mammalian cells to a cluster of E. Coli genes, encoding machinery for building a complex molecule. Colibactin is one of many ephemeral compounds that scientists suspect microbes make. Over the past decade, Balskus's team has proved the colibactin molecule by studying the microbial machinery responsible for its production. Her colleagues and her have pieced together the structure and determined that it damages DNA by forming errant connections within the double helix. Building off this work, the scientific community has uncovered definitive links to cancer.
When the researchers grew colibactin producers alongside bacteria that carried latent viruses, they saw the number of viral particle spike and the growth of many virus-containing bacteria drop. This suggested to the team that the molecule sparked a surge in active, cell killing infections. Colibactin was shown to enter bacteria and damage the DNA as suggested by the team. However, many of the observed microbes seemed to be equipped to protect themselves against the colibactin, the team identified a resistance gene that was encoded within the protein that neutralises the compound in multiple strains of bacteria.
Whilst colibactin clearly has a dangerous side, Balskus suggest that it could be more than a lethal weapon. Both DNA damage and awakened viruses can also induce genetic changes, rather than death, in neighbouring bacteria which in turn could benefit colibactin producers. Balskus’s teams discoveries seem to hint that cancer may be collateral damage cause by whatever else colibactin producing bacteria are doing. Furthermore, Balskus and her team plan to investigate how the compound alters the community of microbes in the gut and which ones disappear and which thrive after exposure to the compound.
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🧠Biology Steered By Artificial Organic Neurons…
Harikesh, P.C., et al. (2022) Organic Electrochemical Neurons and Synapses with Ion Mediated Spiking. Nature Communications. Volume 13, Article number: 901 (2022) doi.org/10.1038/s41467-022-28483-6.
🍄The Secret of Fungi…
Alexis Carteron, Mycorrhizal dominance reduces local tree species diversity across US forests, Nature Ecology & Evolution (2022). DOI: 10.1038/s41559-021-01634-6. www.nature.com/articles/s41559-021-01634-6
🧟Gut Microbes Awaken Zombies
Howard Hughes Medical Institute. "How some gut microbes awaken 'zombie' viruses in their neighbors." ScienceDaily. ScienceDaily, 23 February 2022. <www.sciencedaily.com/releases/2022/02/220223111242.htm>.
Justin E. Silpe, Joel W. H. Wong, et al. The bacterial toxin colibactin triggers prophage induction. Nature, 2022 DOI: 10.1038/s41586-022-04444-3