Navigation Links
Bacterial 'battle for survival' leads to new antibiotic
Date:2/26/2008

CAMBRIDGE, Mass.--MIT biologists have provoked soil-dwelling bacteria into producing a new type of antibiotic by pitting them against another strain of bacteria in a battle for survival.

The antibiotic holds promise for treatment of Helicobacter pylori, which causes stomach ulcers in humans. Also, figuring out the still murky explanation for how the new antibiotic was produced could help scientists develop strategies for finding other new antibiotics.

The work is reported in the February issue of the Journal of the American Chemical Society.

A combination of luck, patience and good detective work contributed to the discovery of the new antibiotic, according to Philip Lessard, research scientist in Professor Anthony Sinskey's laboratory at MIT.

Sinskey's lab has been studying Rhodococcus, a type of soil-dwelling bacteria, for many years. While sequencing the genome of one Rhodococcus species, the researchers noticed that a large number of genes seemed to code for secondary metabolic products, which are compounds such as antibiotics, toxins and pigments.

However, Rhodococcus does not normally produce antibiotics. Many bacteria have genes for antibiotics that are only activated when the bacteria are threatened in some way, so the researchers suspected that might be true of Rhodococcus.

Kazuhiko Kurosawa, a postdoctoral associate in the Department of Biology, decided to try to provoke the bacteria into synthesizing antibiotics by placing them in stressful environments. He tried turning the temperature up and down, then altered the bacteria's growth medium, but nothing worked.

Kurosawa then decided to stress the Rhodococcus bacteria by forcing them to grow in the presence of a competing bacteria, a strain of Streptomyces. Streptomyces produces an antibiotic that normally kills other bacteria, but in one of the experimental test tubes, Rhodococcus started producing its own antibiotic, which wiped out the Streptomyces.

The researchers isolated the antibiotic, dubbed it rhodostreptomycin, and started testing it to see what else it would kill. It proved effective against many other strains of bacteria, most notably Helicobacter pylori. Rhodostreptomycin is a promising candidate to treat H. pylori because it can survive in very acidic environments such as the stomach.

The antibiotic turned out to be a type of molecule called an aminoglycoside, composed of peculiar sugars, one of which has a ring structure that has not been seen before. The ring structure could offer chemists a new target for modification, allowing them to synthesize antibiotics that are more effective and/or stable.

Even if (rhodostreptomycin) is not the best antibiotic, it provides new structures to make chemical derivatives of, said Lessard. This may be a starting point for new antibiotics.

One mystery still to be solved is why Rhodococcus started producing this antibiotic. One theory is that the presence of the competing strain of bacteria caused Rhodococcus to raise the alarm and turn on new genes.

The version of Rhodococcus that produces the antibiotic has a megaplasmid, or large segment of extra DNA, that it received from Streptomyces. A logical conclusion is that the plasmid carries the gene for rhodostreptomycin, but the researchers have sequenced more than half of the plasmid and found no genes that correlate to the antibiotic.

Another theory is that the plasmid itself served as the insult that provoked Rhodococcus into producing the antibiotic. Alternatively, it is possible that some kind of interaction of the two bacterial genomes produced the new antibiotic.

Somehow the genes in the megaplasmid combined with the genes in Rhodococcus and together they produced something that neither parent could make alone, said Lessard.

If scientists could figure out how that happens, they could start to manipulate bacterial genomes in a more methodical fashion to design new antibiotics.


'/>"/>

Contact: Elizabeth Thomson
thomson@mit.edu
617-258-5402
Massachusetts Institute of Technology
Source:Eurekalert

Related medicine news :

1. UCF technique promises to aid doctors ability to identify, treat bacterial infections
2. Why recovery from flu may increase odds of bacterial infection
3. Bacterial toxin closes gate on immune response, Penn researchers discover
4. Nerites Receives NIH Grant to Study Novel Treatment for Preventing Dangerous Bacterial Infections on Urinary Stents and Catheters
5. Forsyth launches 1-of-a-kind core service to enable rapid identification of bacterial samples
6. First look at an enzyme target for antibacterial and cancer drugs
7. Breath test can discriminate between a bacterial overgrowth and IBS
8. Antibacterial chemical disrupts hormone activities
9. GenPrime Initiates External Clinical Trials of its Bacterial Contamination Test for Rapid Detection of Bacteria in Platelets
10. Early Bacterial Infection May Boost Asthma Risk
11. New viruses to treat bacterial diseases -- My enemies enemy is my friend
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/12/2016)... ... February 12, 2016 , ... A lot has been reported about the fitness ... access to health and wellness resources most Americans could ever dream of having at ... a schedule as frenetic as the U.S. President. , In honor of President’s ...
(Date:2/12/2016)... ... ... The Central Coast Autism Spectrum Center (CCASC) invites teens ages 11-18 to its annual Winter ... teens with and without special needs to gather in a safe and supportive environment. Volunteers ... will take place on Saturday, Feb. 13 from 7 to 9:30 p.m. at Elks Lodge, ...
(Date:2/12/2016)... , ... February 12, 2016 , ... Yisrayl Hawkins, Pastor ... article this week that uncovers what he says are the real facts surrounding all ... the Bible from parents and Sunday school teachers, and Yisrayl says there is more ...
(Date:2/12/2016)... ... February 12, 2016 , ... Planet Future ... new cartoon style themes are great for showcasing pictures, videos as well as text ... titles like introductions, lower thirds, transitions and a beautiful frame overlay. Pixel Film Studios ...
(Date:2/12/2016)... ... ... Dignity Health named Dr. Scott Bingham the Facility Medical Director of the ... licensed under Dignity Health Arizona General Hospital , which opened last year in ... our new freestanding emergency room delivers the highest quality care to Mesa and the ...
Breaking Medicine News(10 mins):
(Date:2/11/2016)... SAN FRANCISCO , Feb. 11, 2016  Kindred ... focused on saving and improving the lives of pets, ... Technical Section of the New Animal Drug Application (NADA) ... the pivotal field study (KB0120) of Zimeta for the ... by the Company. --> ...
(Date:2/11/2016)... N.Y. , Feb. 11, 2016  Governor Andrew ... that will create 1,400 jobs throughout Western ... a partnership with the SUNY Polytechnic Institute, includes a ... Conventus Building in Buffalo , as ... foot manufacturing facility in Dunkirk . ...
(Date:2/11/2016)... 11, 2016 Potrero Medical, Inc., the developer of ... the appointment of George M. Rapier, III , MD, ... TX , WellMed is one of the nation,s largest ... HMO members in Texas and ... of his own internal medicine practice, he has been instrumental ...
Breaking Medicine Technology: