Navigation Links
Syracuse University scientists discover how some bacteria may steal iron from their human hosts
Date:7/31/2008

Like their human hosts, bacteria need iron to survive and they must obtain that iron from the environment. While humans obtain iron primarily through the food they eat, bacteria have evolved complex and diverse mechanisms to allow them access to iron. A Syracuse University research team led by Robert Doyle, assistant professor of chemistry in The College of Arts and Sciences, discovered that some bacteria are equipped with a gene that enables them to harvest iron from their environment or human host in a unique and energy efficient manner. Doyle's discovery could provide researchers with new ways to target such diseases as tuberculosis. The research will be published in the August issue (volume 190, issue 16) of the prestigious Journal of Bacteriology, published by the American Society for Microbiology.

"Iron is the single most important micronutrient bacteria need to survive," Doyle says. "Understanding how these bacteria thrive within us is a critical element of learning how to defeat them."

Doyle's research group studied Streptomyces coelicolor, a Gram-positive bacteria that is closely related to the bacteria that causes tuberculosis. Streptomyces is abundant in soil and in decaying vegetation, but does not affect humans. The TB bacteria and Streptomyces are both part of a family of bacteria called Actinomycetes. These bacteria have a unique defense mechanism that enables them to produce chemicals to destroy their enemies. Some of these chemicals are used to make antibiotics and other drugs.

Actinomycetes need lots of iron to wage chemical warfare on its enemies; however, iron is not easily accessible in the environments in which the bacteria live e.g. human or soil. Some iron available in the soil is bonded to citrate, making a compound called iron-citrate. Citrate is a substance that cells can use as a source of energy. Doyle and his research team wondered if the compound iron-citrate could be a source of iron for the bacteria. In a series of experiments that took place over more than two years, the researchers observed that Streptomyces could ingest iron-citrate, metabolize the iron, and use the citrate as a free source of energy. Other experiments demonstrated that the bacteria ignored citrate when it was not bonded to iron; likewise, the bacteria ignored citrate when it was bonded to other metals, such as magnesium, nickel, and cobalt.

The next task was to uncover the mechanism that triggered the bacteria to ingest iron-citrate. Computer modeling predicted that a single Streptomyces gene enabled the bacteria to identify and ingest iron-citrate. The researchers isolated the gene and added it to E. coli bacteria (which is not an Actinomycete bacteria). They found that the mutant E. coli bacteria could also ingest iron-citrate. Without the gene, E. coli could not gain access to the iron.

"It's amazing that the bacteria could learn to extract iron from their environment in this way," Doyle says. "We went into these experiments with no idea that this mechanism existed. But then, bacteria have to be creative to survive in some very hostile environments; and they've had maybe 3.5 billion years to figure it out."

The Streptomyces gene enables the bacteria to passively diffuse iron-citrate across the cell membrane, which means that the bacteria do not expend additional energy to ingest the iron. Once in the cell, the bacteria metabolize the iron and, as an added bonus, use the citrate as an energy source. Doyle's team is the first to identify this mechanism in a bacteria belonging to the Actinomycete family. The team plans further experiments to confirm that the gene performs the same signaling function in tuberculosis bacteria. If so, the mechanism could potentially be exploited in the fight against tuberculosis.

"TB bacteria have access to an abundant supply of iron-citrate flowing through the lungs in the blood," Doyle says. "Finding a way to sneak iron from humans at no energy cost to the bacteria is as good as it gets. Our discovery may enable others to figure out a way to limit TB's access to iron-citrate, making the bacteria more vulnerable to drug treatment."


'/>"/>

Contact: Sara Miller
semortim@syr.edu
315-443-9038
Syracuse University
Source:Eurekalert

Related biology news :

1. A study by the MUHC and McGill University opens a new door to understanding cancer
2. University of Pennsylvania researchers develop formula to gauge risk of disease clusters
3. University of Oregon researcher finds that on waters surface, nitric acid is not so tough
4. Bioengineers at University of Pennsylvania devise nanoscale system to measure cellular forces
5. Binghamton University researchers investigate evolving malaria resistance
6. Antioxidant to retard wrinkles discovered by Hebrew University researcher
7. Society for General Microbiology 161st Meeting, University of Edinburgh
8. Boston University biomedical engineers find chink in bacterias armor
9. KAUST and American University in Cairo to collaborate on research and academic development
10. UNH becomes first university in nation to use landfill gas as primary energy source
11. University of Minnesota study refutes belief that black men have more aggressive prostate cancer
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/2/2016)... -- Perimeter Surveillance & Detection Systems, Biometrics ... Support & Other Service  The latest report ... analysis of the global Border Security market . ... $17.98 billion in 2016. Now: In November ... software and hardware technologies for advanced video surveillance. ...
(Date:5/16/2016)...   EyeLock LLC , a market leader of ... an IoT Center of Excellence in Austin, ... of embedded iris biometric applications. EyeLock,s iris ... security with unmatched biometric accuracy, making it the most ... EyeLock,s platform uses video technology to deliver a fast ...
(Date:4/28/2016)... FRANCISCO and BANGALORE, India , ... of EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... provider, today announced a global partnership that will ... way to use mobile banking and payment services. ... is a key innovation area for financial services, but it ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... 2016  Liquid Biotech USA ... a Sponsored Research Agreement with The University of ... from cancer patients.  The funding will be used ... with clinical outcomes in cancer patients undergoing a ... be employed to support the design of a ...
(Date:6/24/2016)... Raleigh, NC (PRWEB) , ... June 24, 2016 , ... ... find the most commonly-identified miRNAs in people with peritoneal or pleural mesothelioma. Their findings ... here to read it now. , Diagnostic biomarkers are signposts in the blood, ...
(Date:6/23/2016)... Md. , June 23, 2016 A person ... from the crime scene to track the criminal down. ... the U.S. Food and Drug Administration (FDA) uses DNA evidence ... Sound far-fetched? It,s not. The FDA ... sequencing to support investigations of foodborne illnesses. Put as simply ...
(Date:6/23/2016)...   EpiBiome , a precision microbiome engineering company, ... financing from Silicon Valley Bank (SVB). The financing will ... its drug development efforts, as well as purchase additional ... has been an incredible strategic partner to us – ... would provide," said Dr. Aeron Tynes Hammack , ...
Breaking Biology Technology: