(Press-News.org) When a single bacterial cell divides into two during periods of rapid growth, it doesn’t split in half once it reaches a predetermined size. Instead, data has shown, a cell will divide once it has added a certain amount of mass.
The two processes sound similar, but they each carry different risks. Many researchers believed it was a safer bet for the cell if it split once it reached a certain size.
New mathematical modeling from the Kenneth P. Dietrich School of Arts and Sciences shows the risks may have been miscalculated, however, because previous calculations have ignored the drivers of cell division at the molecular scale. Their findings were published in the journal Physical Review Letters.
“Trying to hit a target size before dividing seems like the best strategy for maintaining a precise cell size,” said Andrew Mugler, associate professor in the Department of Physics and Astronomy. “But when you look at what bacteria do, it looks like they use the second-best strategy.”
Dividing each time a cell reaches a target size, known as the sizer strategy, seemed to be the best way to constrain the size of a cell. If something goes wrong and the cell gets too big or too small, it could be easily sorted out in the next generation — it just needs to get back to its target size.
But if something goes wrong using the so-called adder strategy, the cell takes longer to get back to its original size. That’s because the method relies on knowing how much a cell grew since its last division. Overall, the adder was thought to result in a less precise size distribution.
So why do cells use this adder method?
First author Motasem ElGamel, a doctoral student in the Department of Physics and Astronomy, designed a model that goes beyond the scale of the cell and includes molecular level changes as well. He found the adder method is more precise, researchers have just misunderstood its true nature.
Cells don’t divide when they grow a certain amount of mass, but when they add a specific number of a certain molecule. The two measures do grow in parallel — more molecules equals more mass — but considering them together has turned out to be key.
When ElGamel took the number of molecules into account alongside the additional mass, the adder strategy was more precise and less sensitive to mistakes during replication.
“Until this point, models primarily accounted for variables at the scale of the whole cell — its size, or the time it took to divide, etc. But we know the cell makes these decisions based on amounts of certain molecules in the cell body,” Associate Professor Mugler said. “That’s what needed to be incorporated.”
END
Pitt researchers are solving a mini mystery of cell division
2024-04-17
ELSE PRESS RELEASES FROM THIS DATE:
Sink to source: Does what we put into our plumbing end up back in the water supply?
2024-04-17
When you see an advertisement for a detergent promising to brighten your clothes, something called a fluorescent whitening compound, or optical brightener, is probably involved. Such material absorbs UV light and emits visible blue light via fluorescence. The result? Brighter whites, vibrant colors. Yes, your clothes are glowing.
As it turns out, these brighteners can make their way into the water supply. Luka Vucinic, a lecturer and environmental engineer at Glasgow Caledonian University in London, considers the problem of pollutants like fluorescent whitening compounds, microplastics, ...
More progress needed on ocean protection, Oregon State scientists tell global conference
2024-04-17
CORVALLIS, Ore. – World governments and other leadership bodies are taking vital steps to protect the ocean but more progress is urgently needed, Oregon State University scientists reported today at the eighth Our Ocean Conference in Athens.
“Highly protected areas can safeguard against destructive activities such as high-impact fishing, mining and drilling, allowing marine life to recover and in many cases support nearby human communities,” OSU’s Kirsten Grorud-Colvert said. “We’re honored to ...
Making crops colorful for easier weeding
2024-04-17
To make weeding easier, scientists suggest bioengineering crops to be colorful or to have differently shaped leaves so that they can be more easily distinguished from their wild and weedy counterparts. This could involve altering the crops’ genomes so that they express pigments that are already produced by many plants, for example, anthocyanins, which make blueberries blue, or carotenoids, which make carrots orange. Then, they say, weeding robots could be trained to remove only the weeds using machine learning. The authors outline their proposed strategy on April 17 in the journal Trends in Plant Science.
“To improve ...
Amazon butterflies show how new species can evolve from hybridization
2024-04-17
If evolution was originally depicted as a tree, with different species branching off as new blooms, then new research shows how the branches may actually be more entangled. In "Hybrid speciation driven by multilocus introgression of ecological traits," published in Nature, Harvard researchers show that hybrids between species of butterflies can produce new species that are genetically distinct from both parent species and their earlier forebears.
Writing to Charles Darwin in 1861, naturalist Henry Walter Bates described brightly colored Heliconius butterflies of the Amazon as “a glimpse into the laboratory where Nature manufactures ...
Cedars-Sinai study details workings of short-term memory
2024-04-17
Cedars-Sinai investigators have discovered how brain cells responsible for working memory—the type required to remember a phone number long enough to dial it—coordinate intentional focus and short-term storage of information.
The study detailing their discovery was published in the peer-reviewed journal Nature.
“We have identified for the first time a group of neurons, influenced by two types of brain waves, that coordinate cognitive control and the storage of sensory information in working memory,” ...
Astronomers uncover methane emission on a cold brown dwarf
2024-04-17
Using new observations from the James Webb Space Telescope (JWST), astronomers have discovered methane emission on a brown dwarf, an unexpected finding for such a cold and isolated world. Published in the journal Nature, the findings suggest that this brown dwarf might generate aurorae similar to those seen on our own planet as well as on Jupiter and Saturn.
More massive than planets but lighter than stars, brown dwarfs are ubiquitous in our solar neighborhood, with thousands identified. Last year, ...
Storks fly with a little help from their friends
2024-04-17
With long legs and large wings, the white stork is a prominent star of the pageant that is animal migration. Flying from Europe towards Africa in autumn, and then back again in spring, birds can be seen taking to the sky in conspicuous flocks that herald the changing of the seasons. Now, a study from the Max Planck Institute of Animal Behavior in Konstanz, Germany, has an explanation for how this collective phenomenon forms: the storks are choosing to fly together. With data on lifetime migrations of 158 storks, the study provides the first evidence of the social preference of storks during migration. In a paper, the researchers show that storks chose routes ...
Marine plankton behaviour could predict future marine extinctions, study finds
2024-04-17
Marine communities migrated to Antarctica during the Earth’s warmest period in 66 million years long before a mass-extinction event.
All but the most specialist sea plankton moved to higher latitudes during the Early Eocene Climatic Optimum, an interval of sustained high global temperatures equivalent to worst case global warming scenarios.
When the team, comprised of researchers from the University of Bristol, Harvard University, University of Texas Institute for Geophysics and the University of Victoria, compared biodiversity and global community structure, they found ...
Does using your brain more at work help ward off thinking, memory problems?
2024-04-17
About The Study: The results of this systematic review and meta-analysis demonstrate that most people experiencing homelessness have mental health disorders, with higher prevalences than those observed in general community samples. Specific interventions are needed to support the mental health needs of this population, including close coordination of mental health, social, and housing services and policies to support people experiencing homelessness with mental disorders.
Authors: Rebecca Barry, Ph.D., of the University of Calgary, is the corresponding author.
To access the embargoed study: Visit our For The Media website at this ...
Examining sex differences in autism heritability
2024-04-17
About The Study: The findings of this study including more than 1 million Swedish children suggest that the degree of phenotypic variation attributable to genetic differences (heritability) differs between males and females, indicating that some of the underlying causes of the condition may differ between the two sexes. The skewed sex ratio in autism spectrum disorder may be partly explained by differences in genetic variance between the sexes.
Authors: Benjamin H.K. Yip, Ph.D., of the Chinese University of Hong Kong, and Sven Sandin, Ph.D., of the Karolinska Institutet in Stockholm, are the corresponding authors.
To access the embargoed ...