Breaking News
December 17, 2017 - Teens Acting Badly? Smog Could Be to Blame
December 17, 2017 - FDA Says ‘Yes’ to Short-Acting Insulin Admelog
December 17, 2017 - Vaping popular among teens; opioid misuse at historic lows
December 17, 2017 - Lower Urinary Symptoms Occur in Almost All Patients with SSc
December 17, 2017 - Genetic mutation in extended Amish family in Indiana protects against aging and increases longevity (Update)
December 16, 2017 - Butler Hospital launches international Alzheimer’s disease prevention study
December 16, 2017 - iMedicalApps: Virtual Reality Boosts Self-Confidence for Med Students
December 16, 2017 - Researchers validate five new genes responsible for Amyotrophic Lateral Sclerosis
December 16, 2017 - New genetic analysis of candidiasis reveals surprising fungal sex secrets
December 16, 2017 - New high precision machine-learning model could help accelerate drug discovery
December 16, 2017 - Groundbreaking gene therapy trial brings cure for hemophilia closer
December 16, 2017 - Racial Differences Seen in IgG4 Disease
December 16, 2017 - Treacher Collins Syndrome
December 16, 2017 - New approach to tracking how deadly ‘superbugs’ travel could slow their spread
December 16, 2017 - Muscle paralysis may promote breakdown of bones
December 16, 2017 - WSU scientists create injectable dye to track progression of diseases
December 16, 2017 - Kaiser Permanente delivers clot-busting drugs to stroke patients more than twice as fast as national rates
December 16, 2017 - Some Great Holiday Foods for Weight Loss
December 16, 2017 - Shared Decision-Making Strategies for Lung Ca Screening Get High Marks
December 16, 2017 - Lactic acid bacteria can protect against Influenza A virus, study finds
December 16, 2017 - Cancer immunotherapy’s effectiveness may depend on patient’s genetic makeup
December 16, 2017 - Researchers explore patient-doctor conversations, best practices linked to opioid tapering
December 16, 2017 - ‘Virtual child’ to help professionals learn key techniques to treat children with autism
December 16, 2017 - IU scientists discover way to make drug treatment more successful against malaria
December 16, 2017 - Prostate cancer researchers find significant disparities between two liquid biopsy providers
December 16, 2017 - ED-Diagnosed Lung Ca Patients Worse Off: Clin Onc News Report
December 16, 2017 - Calcium in Urine Test: MedlinePlus Lab Test Information
December 16, 2017 - Pregnancy-related conditions taken together leave moms—and dads—at risk
December 16, 2017 - Research uncovers mechanism implicated in defective function of tumor-associated dendritic cells
December 16, 2017 - OncoBreak: Stubborn Racial Disparities; Paid Medical Leave & Chemo; DIY Gene Tests
December 16, 2017 - Critical link between obesity and diabetes has been identified
December 16, 2017 - Transfusion dependence reduces access to high-quality end-of-life care for leukemia patients
December 16, 2017 - Porvair and Suzhou Tianlong Bio to develop epigenetic analysis technologies
December 16, 2017 - FDA Approves Ixifi (infliximab-qbtx), a Biosimilar to Remicade
December 16, 2017 - Morning Break: Trump to Get Check-Up; Cancerous Transplant; Death Knell for MIPS?
December 16, 2017 - First transcatheter implant for diastolic heart failure successful
December 16, 2017 - ‘Sushi-like’ nanodiscs provide structural snapshots of misfolding proteins
December 16, 2017 - Inherited gene variation may be to blame for poor survival of patients with early-onset breast cancer
December 16, 2017 - Sign-up deadline is Friday, but some people may get extra time
December 16, 2017 - Higher Booze Taxes Might Pay Off for Public Health
December 16, 2017 - Regular Activity in Midlife Spares Joints in Women
December 16, 2017 - Rain May Not Cause Achy Joints After All: MedlinePlus Health News
December 16, 2017 - MedDiet adherence doesn’t affect acute heart failure mortality
December 16, 2017 - HKBU experts develop new generation of smart anti-cancer drug molecules
December 16, 2017 - Chronic Kidney Disease Audit finds wide variations in coding of CKD patients in primary care
December 16, 2017 - Scientists use nanoparticles to fight Mucoviscidosis
December 16, 2017 - Increasing physical activity decreases risk of death from lymphoma
December 16, 2017 - Fear compromises the health, well-being of immigrant families, survey finds
December 16, 2017 - Rejected antibiotic candidate could be worth a second look, research finds
December 16, 2017 - Is Nation on the Right Track to Combat Opioid Crisis?
December 16, 2017 - Arthritis No Longer Just a Disease of the Old: MedlinePlus Health News
December 16, 2017 - Study reveals biology behind why muscle stem cells respond differently to aging or injury
December 16, 2017 - Family members without inherited mutation have increased risk of melanoma
December 16, 2017 - Researchers reveal previously unknown mechanism that inhibits cells’ ability to develop into tumors
December 16, 2017 - Studies highlight potential of fMRI applications to detect, treat epilepsy in children
December 16, 2017 - Active surveillance proposed as first-line approach to manage patients with low-risk PMC of the thyroid
December 16, 2017 - Patients’ life values affect their attendance at medical treatment for pelvic-floor dysfunction
December 16, 2017 - Experts consider hazards of antibiotic resistances to be high
December 16, 2017 - Study finds erectile dysfunction as risk factor for early cardiovascular disease
December 16, 2017 - Amber-tinted glasses may reduce insomnia severity
December 16, 2017 - Arthritis Drug Seen Lowering GvHD Risk
December 16, 2017 - Atoh1, a potential Achilles’ heel of Sonic Hedgehog medulloblastoma
December 15, 2017 - Cornell engineers develop new method to measure vital signs using radio waves
December 15, 2017 - Rutgers studies highlight need for salon clients, workers to protect themselves from health risks
December 15, 2017 - FDA Approves Nucala (mepolizumab) for Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss Syndrome)
December 15, 2017 - Morning Break: CVS Buying Aetna; Uterus Transplant Baby; Your Brain on Drugs, Redux
December 15, 2017 - Social phobia linked to autism and schizophrenia
December 15, 2017 - Timestrip technology helping to prevent missed vaccinations
December 15, 2017 - Researchers win NIH grants for Alzheimer’s research on Amish resilience and rapid onset
December 15, 2017 - Mitochondrial error-correction mechanism essential for energy production of cells
December 15, 2017 - New report reveals steep rise in lung disease admissions to emergency departments during winter
December 15, 2017 - Study finds social stigma as barrier to successful treatment of children with HIV in Ethiopia
December 15, 2017 - Health Tip: Keep Gift-Giving Stress Under Wraps
December 15, 2017 - Long Stoppage of Bisphosphonates Tied to More Fractures
December 15, 2017 - Triglycerides Test: MedlinePlus Lab Test Information
December 15, 2017 - Study shows interventions, though few, can be effective for students with high-functioning autism
December 15, 2017 - Higher blood sugar during first trimester of pregnancy increases child’s risk of congenital heart defect
December 15, 2017 - Study tests accuracy of laboratory-developed cancer tests and FDA-approved companion diagnostics
December 15, 2017 - Extracellular vesicles can be used to effectively delay progression of kidney damage
December 15, 2017 - Targeted lung cancer treatments may benefit smokers and non-smokers alike
Biologists reveal how bacterial cells thrive in oxygen-poor environments

Biologists reveal how bacterial cells thrive in oxygen-poor environments

image_pdfDownload PDFimage_print

Columbia University biologists have revealed a mechanism by which bacterial cells in crowded, oxygen-deprived environments access oxygen for energy production, ensuring survival of the cell. The finding could explain how some bacteria, such as Pseudomonas aeruginosa (P. aeruginosa), are able to thrive in oxygen-poor environments like biofilms and resist antibiotics.

P. aeruginosa biofilm infections are a leading cause of death for people suffering from cystic fibrosis, a genetic condition that affects the lungs and the digestive system,” said Principal Investigator Lars Dietrich, an associate professor of biological sciences. “An understanding of the pathways that contribute to the survival and virulence of P. aeruginosa and other bacteria able to exist in oxygen-starved environments could inform treatment approaches for many of these and other immunocompromised patients.”

The study appears this week in the journal eLife.

Bacteria rarely live by themselves as single-celled organisms. Most instead grow in communities, leveraging the strength of numbers to form a biofilm with tissue-like properties similar to a scaffold that serves to fortify the community, making it up to 1,000 times more resistant to most antibiotics.

Each individual cell must on its own extract electrons from food that are then transported along the cell’s membrane until they reach an oxygen molecule. The energy released during this metabolic process is used to sustain life. As communities of bacteria continue to grow and form into a biofilm, however, they can become overcrowded, creating an environment where each cell has to compete for limited nutrients and oxygen to survive.

Research has shown that some bacteria, including P. aeruginosa, have evolved different strategies to respond to and cope with the low-oxygen conditions in biofilms. Communities of bacteria can, for example, change the overall structure of the biofilm so that its surface area-to-volume ratio is higher and a larger proportion of the cells inside are able to access the oxygen on the outside. P. aeruginosa can also make molecules called phenazines, which help to shuttle electrons from the inside to the outside of the cell and ultimately to oxygen available at a distance. Another strategy is to make alternative versions of terminal oxidases, enzymes in the membrane that transfer electrons to oxygen, which use oxygen more efficiently or are better at scavenging oxygen when its concentration is low. While there have been numerous studies done to examine the importance of these enzymes and strategies for P. aeruginosa growth, they’ve largely been conducted in well-oxygenated liquid cultures in the lab. When P. aeruginosa infects an actual host, such as a human, it often grows as a biofilm and encounters vastly different conditions.

With federal funding from the National Institutes of Health and the National Science Foundation, Dietrich, first author Jeanyoung Jo, and their colleagues set out to better understand whether specific terminal oxidases are important for P. aeruginosa metabolism in biofilm communities, how phenazines can compensate for low oxygen levels, and how these adapted strategies may contribute to P. aeruginosa‘s ability to cause infections.

They found that the electron transport chain so critical to the conversion of electrons to energy can and is operating deep down in the oxygen-deprived biofilm and that in these environments, the bacterium depends on a specific part of the chain’s terminal oxidase – a protein called CcoN4 – to access oxygen and grow normally. Cells lacking this protein do not survive as well as cells with it and the researchers believe therefore that CcoN4 contributes to the bacterium’s virulence. They also found that CcoN4 plays a role in using phenazines optimally within biofilms. Though these phenazines have previously been shown to metabolically compensate for the low-oxygen conditions in P. aeruginosa biofilms, the mechanism allowing for this had remained a scientific mystery.

“This bacterium is a master at finding different strategies to access oxygen,” Dietrich said. “We knew that phenazines were involved and that they were somehow helping the cell get oxygen, but we didn’t know how. It appears they are coming from the electron transport chain. That’s an important revelation. We know that bacterial cells have different ways of metabolizing energy in oxygen-rich environments, but for the longest time we couldn’t figure out how they were doing it when oxygen is difficult to access.”

The findings could have big implications for the treatment of P. aeruginosa biofilm infections, as an understanding of the pathways that contribute to P. aeruginosa survival and virulence could inform treatment approaches for patients. Developing therapies that block CcoN4-containing terminal oxidases, for example, would weaken the bacterium and its ability to cause infection.

“We’re starting to understand more and more how cells are able to survive in pretty horrible circumstances,” Dietrich said. “We’re understanding the mechanism. Now we can begin to look for ways to shut down that process.”

Tagged with:

About author

Related Articles