Washington, Mar 31 (ANI): A new generation of natural antibiotics-called nisin variants-can now kill food bacteria and other pathogens that cause food-related diseases.
Bio-engineered by researchers at University College Cork, nisin can kill harmful micro-organisms such as MRSA and the food-borne pathogen, Listeria monocytogenes.
Nisin is an antimicrobial protein produced naturally by a bacterium called Lactococcus lactis.
The researchers explained how they altered different amino acids in nisin and created a family of variants, each slightly different from the naturally occurring protein.
The bioengineered nisin variants possessed greater activities than the parent molecule against a range of important clinical pathogens including MRSA, VRE (Vancomycin resistant Enterococci) and the food-borne pathogen Listeria monocytogenes.
Already, nisin is used as a natural biopreservative in heat-treated and low-pH foods. It has a long record of safe use and is one of only a few such compounds to have been applied commercially.
As antibiotic resistance has become a serious public threat, the scientists are hoping that these enhanced nisin variants could become acceptable alternatives to the range of antimicrobials currently available.
Using enhanced nisin variants against food-borne pathogens such as Listeria is particularly significant as this bacterium is among the most naturally nisin resistant pathogens.
Listeria monocytogenes usually causes illness in vulnerable groups-such as pregnant women, babies, the elderly and people with reduced immunity-whose illness is often severe and life threatening.
The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing such as soft cheeses and hot dogs.
Thus, scientists are working towards developing improved versions of nisin that specifically target Listeria, which could turn out to be a more preferable option than the current form of nisin for some food biopreservation applications.
“For example, Nisin has the potential to be a safer alternative due to its high antibacterial activity and nontoxicity to humans. The fact that different nisin derivatives can now be generated to target specific pathogenic organisms makes it even more attractive as a natural and potent antimicrobial for clinical and food use,” said the authors of the study.
They added: “It may also be possible to reduce the levels of other preservatives such as salt, sugar and certain chemicals often used in high concentrations to inhibit bacterial growth, ultimately leading to not only safe but healthier foods.”he study was presented at the Society for General Microbiology meeting in Harrogate. (ANI)
Former Bush official says he was asked to raise threat level before 2004 polls
Washington, Aug.21 (ANI): The first secretary of homeland security, Tom Ridge, has asserted in a new book that he was pressured by top advisers to President George W. Bush to raise the national threat level just before the 2004 election in what he suspected was an effort to influence the vote.
Ridge said Attorney General John Ashcroft and Defense Secretary Donald H. Rumsfeld pushed him to elevate the public threat posture but he refused.
According to the New York Times, Ridge now calls it a “dramatic and inconceivable” event that “proved most troublesome” and reinforced his decision to resign.
The provocative allegation provides fresh ammunition for critics who have accused the Bush administration of politicizing national security.
Keith M. Urbahn, a spokesman for Rumsfeld, said the defense secretary supported letting the public know if intelligence agencies believed there was a greater threat, and pointed to a variety of chilling Qaeda warnings in those days, including one tape vowing that “the streets of America will run red with blood.”
Ashcroft could not be reached for comment. But Mark Corallo, who was his spokesman at the Justice Department, dismissed Ridge’s account.
“Didn’t happen,” he said. “Now, would be a good time for Mr. Ridge to use his emergency duct tape.”
Ridge’s book, called “The Test of Our Times” and due out September 1 from Thomas Dunne Books, is the latest by a Bush adviser to disclose internal disagreements and establish distance from an unpopular administration.
In the book, Ridge complains that he was never invited to National Security Council meetings, that Rumsfeld would rarely meet with him and that the White House pressured him to include a justification for the Iraq war in a speech. (ANI)