Showing posts with label antibiotic drug resistance. Show all posts
Showing posts with label antibiotic drug resistance. Show all posts

Monday, September 1, 2014

Synthesis produces new fungus-derived antibiotic

A fortuitous collaboration has led to the total synthesis of a recently discovered natural antibiotic. The laboratory recreation of a fungus-derived antibiotic, viridicatumtoxin B, may someday help bolster the fight against bacteria that evolve resistance to treatments in hospitals and clinics around the world.


As part of the process, Rice organic chemist K.C. Nicolaou and structural biologist Yousif Shamoo and their colleagues created and tested a number of variants of viridicatumtoxin B that could lead to the simplified synthesis of a new generation of more effective antibiotics.

The work reported this month in the Journal of the American Chemical Society (JACS) focused on a tetracycline discovered in 2008 by scientists who isolated small amounts from penicillium fungi. The yield wasn't nearly enough for extensive testing, but it provided a basis for the discoverers to analyze its structure through magnetic resonance imaging, Nicolaou said.

"We're inspired by molecules that are biologically active and have the potential to become medicines one day," he said.

The new discovery belongs to a class of antibiotics known as tetracyclines for their distinctive molecular structure. They proved potent  in  initial tests on
Gram-positive bacteria, so named for a staining technique to mark bacteria that are more susceptible to antibiotics than their Gram-negative counterparts.

The first tetracyclines, discovered in the late 1940s, ushered in a new class of
powerful antibacterial agents to treat high-mortality diseases,    among  them
anthrax and plague as well as such bacterial infections as chlamydia, syphilis
and Lyme disease.

To find new weapons, especially  against  "superbugs" that resist nearly all antibiotics, synthetic chemists pursue the complex  process  of  mimicking the
structures of effective natural molecules as they build drug candidates atom by atom.

"Tetracyclines are widespread antibiotics today, but bacteria are building resistance to a lot of them," Nicolaou said. "This new tetracycline is not plentiful in nature, so the only way we can make it available to study by biologists for its potential in medicine is to synthesize it in the laboratory."


Ref : http://pubs.acs.org/doi/abs/10.1021/ja506472u

Synthesis produces new fungus-derived antibiotic 

Monday, November 25, 2013

Researchers discover new approach to tackle global threat of antibiotic drug resistance

Researchers at McMaster University are addressing the crisis in drug resistance with a novel approach to find new antibiotics.

"We have developed technology to find new antibiotics using laboratory conditions that mimic those of infection in the human body," said Eric Brown, professor in the Department of Biochemistry and Biomedical Sciences.

He is the lead author of the paper published in the online edition of Nature Chemical Biology today. Brown is also a member of the Michael G. DeGroote Institute for Infectious Disease Research (IIDR).

The findings report on the discovery of chemical compounds that block the ability of bacteria to make vitamins and amino acids, processes that are emerging as Achilles' heels for bacteria that infect the human body.

"The approach belies conventional thinking in antibiotic research and development, where researchers typically look for chemicals that block growth in the laboratory under nutrient-rich conditions, where vitamins and amino acids are plentiful," said Brown. "But in the human body these substances are in surprisingly short supply and the bacteria are forced to make these and other building blocks from scratch."

Brown's research group targeted these processes looking for chemicals that blocked the growth of bacteria under nutrient-limited conditions.

"We threw away chemicals that blocked growth in conventional nutrient-rich conditions and focused instead on those that were only active in nutrient-poor conditions," he said.

"We're taking fresh aim at bacterial vitamin and amino acid production and finding completely novel antibacterial compounds."

The approach and the new leads discovered by Brown's lab have potential to provide much-needed therapies to address the growing global threat of antibiotic drug resistance.


"When it comes to this kind of new drug discovery technology, Brown's group are fishing in a new pond," said professor Gerry Wright, director of the IIDR. "These leads have real prospects as an entirely new kind of antibacterial therapy."