Breaking News
February 21, 2018 - Household Products May Pollute the Air as Much as Your Car Does: Study
February 21, 2018 - Combo Bests Targeted Agent in mRCC
February 21, 2018 - Researchers discover brain pathway that dissociates opioid addiction from analgesia
February 21, 2018 - Scientists uncover how newly discovered gene helps grow blood vessels
February 21, 2018 - Brain’s quality control process holds clues to obesity’s roots
February 21, 2018 - Researchers to study whether menstrual cups can help prevent vaginal infections
February 21, 2018 - MS patients who feel stigmatized more likely to suffer from depression
February 21, 2018 - Vitamin D supplementation during pregnancy could protect against childhood obesity
February 21, 2018 - Lower-Quality Medical Tx Might Have Skewed Key PCI vs CABG Trials
February 21, 2018 - Love and fear are visible across the brain instead of being restricted to any brain region
February 21, 2018 - Adults with congenital heart disease have increased risk for dementia, study finds
February 21, 2018 - Clinical trial studying type 1 diabetes reaches full enrollment
February 21, 2018 - Father’s stress affects the brain development of offspring, mice study shows
February 21, 2018 - ESRD Death Declines in Vasculitis Patients
February 21, 2018 - Taking ibuprofen for long periods found to alter human testicular physiology
February 21, 2018 - Google AI device could predict a person’s risk of a heart attack
February 20, 2018 - FDA Approves Domestic Source for Tc-99m Isotopes
February 20, 2018 - Sanofi rejects refund demand faces Philippine suit over dengue vaccine (Update)
February 20, 2018 - Researchers discover that activation of specific enzyme may help suppress tumor metastasis
February 20, 2018 - Blood or marrow transplantation survivors have higher risk of cognitive impairment
February 20, 2018 - Booze Beats Pot at Being Unhealthy: Oregon Poll
February 20, 2018 - Morning Break: ’20 Years Late’; Drugs in the Dirt; Catching Flu in the Dorm
February 20, 2018 - Another piece to the puzzle in naked mole rats’ long, cancer-free life
February 20, 2018 - Scientists identify four viruses that can produce insulin-like hormones
February 20, 2018 - New e-Health solution developed to prevent cardiovascular disease, dementia in senior citizens
February 20, 2018 - New genetic risk score could help guide screening decisions for prostate cancer
February 20, 2018 - Study finds higher risk of stroke among blacks with atrial fibrillation than whites
February 20, 2018 - Physical activity could be used as strategy for diabetes prevention
February 20, 2018 - Researchers develop sensing method for early detection of cancer and diabetes
February 20, 2018 - New wearable electronics could be game-changer for stroke rehabilitation
February 20, 2018 - Immune history influences person’s response to flu vaccine
February 20, 2018 - Research findings could help develop new drugs to prevent, treat dry eye disease
February 20, 2018 - Serenity Now! Learn to Have Patience with Patients
February 20, 2018 - Computer simulation addresses the problem of blood clotting
February 20, 2018 - Women with type 1 diabetes not protected against coronary artery disease
February 20, 2018 - Persistent bloating can be a sign of ovarian cancer, warns charity
February 20, 2018 - Trump administration proposes rule to loosen curbs on short-term health plans
February 20, 2018 - Key protein involved in epigenetic regulation of gene expression guides skin cell renewal
February 20, 2018 - Heart attack symptoms often missed in women
February 20, 2018 - Diagnosis of celiac disease takes 3.5 years for patients who do not report GI symptoms
February 20, 2018 - Study reveals functional dynamics of ion channels
February 20, 2018 - Study explores link between mortality risk and combustible tobacco use
February 20, 2018 - ‘She Trusted Me, and I’d Turned Her Away’
February 20, 2018 - AbbVie and Voyager Therapeutics collaborate to develop new treatments for tauopathies
February 20, 2018 - Fast food makes the immune system more aggressive in the long term
February 20, 2018 - Therapeutic target for glaucoma could have treatment ramifications for Alzheimer’s and Parkinson’s
February 20, 2018 - Overcoming Negative Reviews | Medpage Today
February 20, 2018 - MyD88—villain of allergies and asthma
February 20, 2018 - Food scientists develop rapid screening technique to detect pesticide residue in vegetables
February 20, 2018 - Lab-grown cerebellar cells may help explain how ASD develops at molecular level
February 20, 2018 - Scientists explore connection between bad sleep habits and stiff blood vessels
February 20, 2018 - New Treatment Apalutamide (Erleada) Approved for Prostate Cancer That Resists Hormone Therapy
February 20, 2018 - Do You Really Need My Signature on That?
February 20, 2018 - HIV-1 genetic diversity is higher in vaginal tract than in blood during early infection
February 20, 2018 - Diabetes does not increase work-loss years due to early retirement
February 20, 2018 - Researchers aim to find out how PTSD affects decisions of police
February 20, 2018 - UH Cleveland Medical Center explores novel treatments for uterine fibroids
February 20, 2018 - Flu Vax Efficacy 25% Against Predominant H3N2 Strain So Far
February 20, 2018 - HIV screening most optimal at 25 years of age if no risk factors
February 20, 2018 - Loyola Medicine primary care physician offers advice to minimize risk of flu
February 20, 2018 - Safe sleep recommendations for parents that may help reduce child’s risk of SUID
February 20, 2018 - Why Do So Few Docs Have Buprenorphine Waivers?
February 20, 2018 - Low levels of alcohol good for the brain
February 20, 2018 - Experimental treatment improves invisible symptoms of a man with spinal cord injury
February 20, 2018 - Myriad’s EndoPredict offers better prediction of breast cancer recurrence, analysis shows
February 20, 2018 - Researchers identify fifteen genes that determine our facial features
February 20, 2018 - Morning Break: New Health IT Player; Luxturna No Bargain; Nuclear Freakout
February 20, 2018 - How does it compare? Hospice care at home, at assisted living facility, at nursing home
February 19, 2018 - Scientists develop water-soluble warped nanographene for bioimaging
February 19, 2018 - It’s Not Your Imagination: You’re Hungrier After Losing Weight
February 19, 2018 - Antihypertensive Use At Delivery Rising in Preeclampsia
February 19, 2018 - A centuries-old math equation used to solve a modern-day genetics challenge
February 19, 2018 - Liquid biopsies could be used as new predictive marker for metastatic TNBC
February 19, 2018 - Russian researchers develop new multi-layered biodegradable scaffolds
February 19, 2018 - Are ‘Vaccine Skeptics’ Responsible for Flu Deaths?
February 19, 2018 - Hidden genetic effects behind immune diseases may be missed, study suggests
February 19, 2018 - Emergency nurses experience regular verbal and physical abuse
February 19, 2018 - Study sheds light on biology that guides behavior across different stages of life
February 19, 2018 - Morning Break: Transgender Breast Feeding; Brazilian ‘Pro-Vaxxers’; Post-Stroke Exercise
February 19, 2018 - Meningitis vaccination strategy in Africa found to be effective, economical
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