A scientist looks through a microscope.
(photo credit: INGIMAGE)
To cook an omelet, you have to scramble an egg, and like Humpty Dumpty it can never be put back together again. This is because the egg undergoes a set of physiological and chemical changes as it cooks that cause its chemical bonds to break and its proteins to aggregate, restructuring and setting into a new, final – and irreversible – shape.
However, a new Tel Aviv University study suggests for the first time a novel form of protein aggregation that is both reversible and has positive physiological consequences for cells. The discovery may eventually lead to new therapies for neurodegenerative conditions such as Alzheimer’s, Parkinson’s and “mad cow” diseases, said Prof. Martin Kupiec and Dr. Kobi Simpson-Lavy, both of TAU’s School of Molecular Cell Biology and Biotechnology and published recently in the journal Molecular Cell.
“Most of the functions within our cells are carried out by proteins, but when these proteins aggregate, they produce a ‘blob’ that renders them inactive,” Kupiec explained. “Protein aggregation tends to increase with age and leads to a number of human diseases, particularly those resulting in neurodegeneration.”
In addition, when proteins adopt an erroneous configuration – when they’re misfolded – the cells attempt to take the clumps apart or to pile them up at particular locations in the cell, to minimize their toxic effect,” he continued. “This process has been linked to the development of a number of neurodegenerative conditions, such as Alzheimer’s, Parkinson’s and ‘mad cow’ diseases.”
The new study examines an entirely different type of protein aggregation that may provide a new mechanism with which to regulate the activity of genes according to changes in the cell’s environment.
The research for the study emerged serendipitously. While Dr. Simpson-Lavy was studying the metabolism of sugars in yeast cells, he noticed that a tagged version of the protein he was observing – Std1 – formed a bright splotch outside the cell’s nucleus whenever glucose was added to the cells. Std1, which is usually present in the nucleus of the cell where the genome lies ended up in an aggregation outside of the nuclei.
The study also suggested that not all protein aggregates are harmful; some play important physiological and regulatory roles. According to the study, the “molecular chaperones” that have been found to fuel many neurodegenerative diseases may have originally been intended to regulate the buildup of non-pathological proteins.
“These results could open the way for possible future treatments that may try to change the aggregation from irreversible to reversible,” he concluded. “If we can find out how to turn an irreversible aggregation into a reversible one, it would be possible to treat neurodegenerative diseases and reverse the effect of the aggregates. In other words, it may still be possible to reconstruct an egg from an omelet.”
CRUMBLING INFRASTRUCTURE COULD BE HEALED
A new self-healing fungi concrete, co-developed by researchers at Binghamton University in New York, could help repair cracks in aging concrete permanently and help save crumbling infrastructure. Mechanical engineering Prof. Congrui Jin found that the problem stems from the smallest of cracks.
“Without proper treatment, cracks tend to progress further and eventually require costly repair,” said Jin. “If micro-cracks expand and reach the steel reinforcement, not only the concrete will be attacked, but also the reinforcement will be corroded, as it is exposed to water, oxygen, possibly CO2 and chlorides, leading to structural failure.”
These cracks can cause huge and sometimes unseen problems for infrastructure. One potentially critical example is the case of nuclear power plants that may use concrete for radiation shielding. While remaking a structure would replace the aging concrete, this would only be a short-term fix until more cracks again spring up. Jin wanted to see if there was a way to fix the concrete permanently.
“This idea was originally inspired by the miraculous ability of the human body to heal itself of cuts, bruises and broken bones,” said Jin. “For the damaged skins and tissues, the host will take in nutrients that can produce new substitutes to heal the damaged parts.”
He and his team set out to find a way to heal concrete and found an unusual answer – a fungus called Trichoderma reesei. When this fungus is mixed with concrete, it originally lies dormant until the first crack appears.
“The fungal spores, together with nutrients, could be placed into the concrete matrix during the mixing process. When cracking occurs, water and oxygen will find their way in. With enough water and oxygen, the dormant fungal spores will germinate, grow and precipitate calcium carbonate to heal the cracks,” explained Jin. “When the cracks are completely filled and ultimately no more water or oxygen can enter inside, the fungi will again form spores. As the environmental conditions become favorable in later stages, the spores could be wakened again.”
The research is still in the fairly early stages, with the biggest issue being the survivability of the fungus within the harsh environment of concrete. However, Jin is hopeful that with further adjustments the, Trichoderma reesei will be able to effectively fill the cracks.
“There are still significant challenges to bring an efficient self-healing product to the concrete market. In my opinion, further investigation in alternative microorganisms such as fungi and yeasts for the application of self-healing concrete becomes of great potential importance,” said Jin.