Tag Archives: Mutated

Your Brain May Have Mutated in Unexpected Ways

Posted on by
Reply

Fragments of mitochondrial DNA can be added to the cell's main genome

wir0man/Getty Images

Mutations in which DNA from energy-producing mitochondria is mistakenly added to a cell's main genome were thought to be extremely rare. Now, studies of brain tissue show that such mutations occur in all of us, and their numbers may be a factor in ageing.

“Not only are they present, but they are abundant in the dorsolateral prefrontal cortex, an area of ​​the brain associated with cognitive abilities.” Ryan Mills At the University of Michigan.

In human cells, almost all of the DNA (about 6 billion letters) resides in the nucleus, but the energy-producing organelles called mitochondria have their own tiny genome of about 16,600 letters.

That's because mitochondria were once free-living bacteria with their own large genome. In the roughly 2 billion years since those bacteria formed a symbiotic relationship with our distant ancestors, most of the original bacterial genome has been lost or transferred to the main genome in the nucleus.

This evidence of transfer has led biologists to know for a long time that fragments of mitochondrial DNA could somehow find their way into the nucleus and then be added to the main genome. But this kind of mutation was thought to be very rare, Mills says. Over the past few years, work by his team and others has shown that this isn't as uncommon as we thought. At least in cancer cells.

Mills and his colleagues showed that these types of mutations also occur in non-cancerous cells by sequencing the DNA of brain tissue samples taken from 1,200 people during post-mortem examinations.

Although another team took the samples and sequenced them, Mills and his colleagues looked for mutations that add mitochondrial DNA to the nuclear genome. “We were just curious,” Mills says.

Not only did they find such mutations, but they also found that they were more prevalent in people who, on average, died younger.

It's not clear whether these mutations are just a symptom of aging or a cause of it, Mills says. “The jury is still out,” he says. “But if you take the entire mitochondrial sequence and put it somewhere in the genome, it's hard for me to believe that it wouldn't have an effect.”

topic:

Source: www.newscientist.com

Mutated, Genetically Unique Strains of Multidrug-Resistant Bacteria Found on the ISS by Biologists

Posted on by
Reply

Enterobacter bugandensis It is mainly present in clinical specimens such as the human gastrointestinal tract.

Example workflow illustrating the process of comparative genomics analysis Enterobacter bugandensis, its prevalence and metabolic interactions within the microbial community, and assess its adaptation success within the ISS habitat. Image credit: Sengupta other., doi: 10.1186/s40168-024-01777-1.

The International Space Station (ISS) is a testament to humanity's achievements in space exploration.

Despite a highly controlled environment characterized by microgravity, increased carbon dioxide levels, and increased solar radiation, microorganisms occupy a unique niche.

These resident microbial bacteria play an important role in influencing the health and well-being of astronauts.

One particularly interesting microorganism is the Enterobacter bugandensis, a Gram-negative bacterium notorious for its multidrug resistance.

“Microorganisms in the built environment have a significant impact on the health of residents,” says the lead author Dr. Kastri Venkateswaran by NASA's Jet Propulsion Laboratory and colleagues.

“The ISS is a highly controlled built environment with extreme conditions such as microgravity, solar radiation, and elevated carbon dioxide levels, providing a unique location to study microbial survival and adaptation. .”

“Recent studies have demonstrated that microorganisms exposed to microgravity acquire antibiotic resistance and become more virulent through rapid mutation and horizontal gene transfer.”

“Prolonged space travel in microgravity can compromise astronauts' immune systems and increase their vulnerability to disease.”

“The microbial population on the ISS can influence the astronauts' microbiome and could be replenished by the arrival of new crew members.”

“Understanding microbial colonization, inheritance, and interactions is therefore critical to ensuring the health of astronauts and managing microbial risks in isolated and confined human habitats.”

In the new study, the authors analyzed 13 bacterial strains. Enterobacter bugandensis It is isolated from the ISS.

Their results show that under stress these strains mutated and became genetically and functionally distinct compared to their terrestrial counterparts.

These strains were able to persist in large numbers on the ISS for long periods of time.

They coexisted with multiple other microorganisms, and in some cases may have helped those microorganisms survive.

“Our comprehensive analysis reveals not only how these interactions shape microbial diversity, but also the factors that may contribute to the potential dominance and inheritance of microorganisms. Ta. Enterobacter bugandensis within the ISS environment,” the researchers said.

“The implications of these findings are twofold,” they added.

“First, we shed light on the behavior, adaptation, and evolution of microorganisms in extreme and isolated environments.”

“Second, it highlights the need for strong precautions to ensure the health and safety of astronauts by mitigating risks associated with potential pathogen threats.”

of findings appear in the diary microbiome.

_____

P. Sengupta other. 2024. Genomic, functional, and metabolic enrichment in multidrug-resistant patients. Enterobacter bugandensis Facilitate survival and succession on the International Space Station. microbiome 12, 62; doi: 10.1186/s40168-024-01777-1

Source: www.sci.news