(Press-News.org) Contact information: Leila Gray
leilag@uw.edu
206-685-0381
University of Washington
Genetically identical bacteria can behave in radically different ways
Uneven distribution of certain mechanisms during cell division creates diversity that can enhance a bacterial population's survival
Although a population of bacteria may be genetically identical, individual bacteria within that population can act in radically different ways.
This phenomenon is crucial in the bacteria's struggle for survival. The more diversity a population of bacteria has, the more likely it will contain individuals able to take advantage of a new opportunity or overcome a new threat, including the threat posed by an antibiotic.
In a recent study, researchers at the University of Washington showed that when a bacterial cell divides into two daughter cells there can be an uneven distribution of cellular organelles. The resulting cells can behave differently from each other, depending on which parts they received in the split.
"This is another way that cells within a population can diversify. Here we've shown it in a bacterium, but it probably is true for all cells, including human cells," said Dr. Samuel Miller, UW professor of microbiology, genome sciences, and medicine and the paper's senior author.
Bridget Kulasekara, who obtained a Ph.D in the UW Molecular and Cellular Biology Program, was the paper's lead author. Other contributors included: Hemantha Kulasekara, Matthias Christen, and Cassie Kamischke, who work in Miller's lab, and Paul Wiggins, UW assistant professor of physics and bioengineering. The paper appears in the online journal eLife.
In an earlier paper, Miller and his colleagues showed that when bacteria divided, the concentration of an important regulatory molecule, called cyclic diguanosine monophosphate (c-di-GMP). was unevenly distributed between the two progeny. c-di-GMP is a second messenger molecule. That finding was published in the journal Science in 2010.
Second messenger molecules transmit signals from sensors or receptors on the cell's external membrane to targets within the cell, where they can rapidly alter a wide variety of cellular functions, such as metabolism and mobility.
The ability to respond to external stimuli quickly is important for the bacteria's survival. For instance, to stay alive, a bacterium must not hesitate to swim towards nutrients or away from toxins. This directional movement of microorganisms, spurred by the presence of a helpful or harmful substance, is known as chemotaxis.
"The effect of second messengers is almost immediate," said Miller. "They allow bacteria to change their behavior within seconds."
To detect the difference in c-di-GMP levels between cells, the researchers used a technique called Förster resonance energy transfer microscopy, or FRET microscopy. This allowed them to measure nanomolar changes of the concentration of c-di-GMP within individual bacteria as the changes happened second by second.
Different concentrations of c-di-GMP can have a profound influence on a cell's behavior. For example, in the bacteria Pseudomonas aeruginosa, cells with high levels of c-di-GMP tend to remain still, adhere to surfaces and form colonies. Those with low levels, on the other hand, tend to actively swim about by using a corkscrew-shaped propeller located at one end of the bacterium.
In the latest study, the Miller and his colleagues worked out the molecular mechanism behind the difference in c-di-GMP concentrations seen between daughter cells.
When Pseudomonas cells divide, they pinch in half to create two daughter cells. Although the cells are genetically identical, only one daughter cell can inherit the bacterium's single propeller. The other cell can synthesize its own propeller, but immediately after division the two cells are quite different.
What Miller and his coworkers report in the eLife paper is that the daughter cell that inherits the propeller also inherits an enzyme that is closely associated with the propeller that degrades c-di-GMP, as well as the organelle involved in directing movement toward or away from stimuli that activates this enzyme.
Together these two organelles work in concert to lower the concentration of c-di-GMP and control swimming.
"What we have shown is that the uneven inheritance of organelles is another way cells have to create diversity and increase the chances of the survival of its species," Miller said.
He added that his team's findings may help explain how bacteria resist antibiotic treatments by always having some cells in their populations be in a slow-growing, resting state. Since antibiotics target fast-growing cells, these resting cells are more likely to survive the treatment. The findings might also help explain how some bacteria are able to adhere to and colonize surfaces such as urinary catheters, intravenous lines and heart valves.
In ongoing research, Miller's team is trying to get a better understanding of the signals that can change second messenger concentrations very quickly and is screening compounds that could interfere with or alter those signals. Such compounds could be used to combat drug resistance, for instance, or inhibit a bacterium's ability to adhere to surfaces and form slime-like colonies, called biofilms, that are highly resistant to antibiotics.
INFORMATION:
The new paper, as well as the earlier study, which appeared in the journal Science in 2010, are both available free online.
Kulasekara et al. c-di-GMP heterogeneity is generated by the chemotaxis machinery to regulate flagellar motility. ELife. 2013;2:e01402.
Chisten M et al. Asymmetrical Distribution of the Second Messenger c-di-GMP upon Bacterial Cell Division. Science. 2010; 328(5983):1295-1297 DOI: 10.1126/science.1188658
The research was funded by the National Institute of Allergy and Infectious Diseases (Grant number: 5U54AI057141-09) the National Science Foundation Graduate Research Fellowship (Grant number 2007047910) and the National Institutes of Health (Grant number 1R21NS067579-0).
Genetically identical bacteria can behave in radically different ways
Uneven distribution of certain mechanisms during cell division creates diversity that can enhance a bacterial population's survival
2014-01-03
ELSE PRESS RELEASES FROM THIS DATE:
Patch outperforms Holter for prolonged heart rhythm tracking
2014-01-03
Patch outperforms Holter for prolonged heart rhythm tracking
Scripps study suggests shift in decades-old practice for detecting irregular heart beats
SAN DIEGO – Research by the Scripps Translational Science Institute (STSI) has found that a small adhesive wireless ...
Researchers report technique that enables patient with 'word blindness' to read again
2014-01-03
Researchers report technique that enables patient with 'word blindness' to read again
MAYWOOD, Il. - In the journal Neurology, researchers report a novel technique that enables a patient with "word blindness" to read again.
Word blindness is a rare neurological ...
Odor receptors discovered in lungs
2014-01-03
Odor receptors discovered in lungs
They're just like those in your nose but instead of conjuring up a cup of coffee they might make you cough
Your nose is not the only organ in your body that can sense cigarette smoke wafting through the air. Scientists at Washington ...
Local factors cause dramatic spikes in coastal ocean acidity
2014-01-03
Local factors cause dramatic spikes in coastal ocean acidity
Fluctuation 'adds insult to injury' for marine creatures
DURHAM, N.C. – A new Duke University-led study has documented dramatic, natural short-term increases in the acidity of a North Carolina estuary.
"The natural ...
EARTH Magazine: Geological travels in Antarctica
2014-01-03
EARTH Magazine: Geological travels in Antarctica
Following in the footsteps of giants
Alexandria, VA – Yesterday, 52 scientists, journalists and tourists were rescued from frozen Antarctic waters, where their ship, the MV Akademik Shokalskiy, had been stuck ...
UT Arlington research may unlock enzyme's role in disease
2014-01-03
UT Arlington research may unlock enzyme's role in disease
A UT Arlington chemist doing National Science Foundation-funded research on enzymes that regulate human biology has uncovered characteristics that could be used to identify predisposition to conditions ...
South African trauma center launches portable electronic trauma health record application
2014-01-03
South African trauma center launches portable electronic trauma health record application
Canadian surgeons collaborate with South African hospital to successfully develop an iPad app for capturing trauma patient data in a low medical resource environment according ...
How 'slippers' can end mascara irritation
2014-01-03
How 'slippers' can end mascara irritation
New test reduces need for animal testing
An end to mascara testing on animals could be in sight thanks to tiny organisms nicknamed 'slipper' and 'eyelash'.
Mascara is a mild irritant, and rabbits have, historically, ...
How best to go about getting seed money through crowdfunding
2014-01-02
How best to go about getting seed money through crowdfunding
It can be by touting yourself, Hebrew University research shows
Jerusalem, January 1, 2014 --- Early on in our careers, many of us were tutored as to how to best write an effective and ...
Earthquake lights linked to rift environments, subvertical faults
2014-01-02
Earthquake lights linked to rift environments, subvertical faults
SAN FRANCISCO – Rare earthquake lights are more likely to occur on or near rift environments, where subvertical faults allow stress-induced electrical currents to flow rapidly to the ...
LAST 30 PRESS RELEASES:
Not hunters but collectors: the bone that challenges the ‘humans wiped out Australian megafauna’ theory
Discovery of new mechanism concerning plasma confinement performance
Humans evolved fastest amongst the apes
Biochar and wetter soils offer breakthrough path to slash farm emissions without cutting crop yields
New biochar-enhanced cement could lock away more carbon dioxide
Strong evidence supports skin-to-skin contact after birth as standard care
Why it’s not just about money: Who goes to the ballet, opera and symphony
Daily step counts of 4,000 or more tied to reduced risk of heart disease, mortality in older women
Number of steps taken matters more for better health in older women than the frequency
Less than half of schoolkids at risk of food anaphylaxis in England prescribed adrenaline ‘antidote’
The Lancet: Antidepressants vary widely in their physical side effects, highlighting the need for personalised prescribing, says major meta-analysis
Scientists discover clean and green way to recycle Teflon®
‘Messy’ galaxies in the early universe struggled to settle
Global supply chains benefit most from who you know
While searching for the world’s oldest ice, scientists find sediment sneaking under the Antarctic ice sheet
Contrasting risk profiles for suicide attempt and suicide
Future-focused conservation index identifies reptiles as highest conservation priority
Ideological polarization and the spread of biased or fake news on Facebook are on the rise, according to a study by the UPF
New study reveals how tiny but powerful gatekeepers guard the nucleus
Discovery of a brown dwarf orbiting a red dwarf through the synergy of ground- and space-based observatories
CPA journal wins prestigious award at high-quality development conference
Disruptive investments can build a cleaner aviation industry
Wearable optical device distinguishes blood flow signals from the brain and scalp
USC-Caltech study moves novel tool to measure brain blood flow closer to the clinic
Changes in colorectal cancer screening modalities among insured individuals
Seaweed makes for eco-friendly tissue scaffolds and reduces animal testing
New study: AI chatbots systematically violate mental health ethics standards
Smoking both cannabis and tobacco may alter brain’s ‘bliss molecule,’ study finds
The rise of longevity clinics: Promise, risk, and the future of aging
Decoding the T-cell burst: Signature genes that predict T-cell expansion in cancer immunotherapy
[Press-News.org] Genetically identical bacteria can behave in radically different waysUneven distribution of certain mechanisms during cell division creates diversity that can enhance a bacterial population's survival