Welcome to the Microbiology Information

The bacterium Listeria monocytogenes lives happily in soil and in your compost heap, but also in water, processed meats, milk and cheese. When humans eat food contaminated with Listeria, they can develop listeriosis, an infection that triggers miscarriage in women and kills people whose immune systems are weak. Scientists would like to understand the molecular mechanisms that transform this bacterium from a harmless soil-dweller to a dangerous human pathogen.

Now, a team at the Pasteur Institute in Paris has taken a major step towards realizing that goal, by mapping the genes that Listeria expresses under different environmental conditions. The research is reported in an advance online publication in the journal Nature on May 17, 2009.

As head of the Pasteur Institute’s Unit of Bacteria-Cell Interactions, Howard Hughes Medical Institute international research scholar Pascale F. Cossart is proud of what she refers to as the first complete bacterial operon map. Pasteur scientists François Jacob and Jacques Monod first described the concept of the operon in 1960. Both were awarded the Nobel Prize in Physiology or Medicine in 1965 for their seminal work on operons. Operons are functional units of DNA that consist of several adjacent genes controlled by a common promoter—a piece of DNA that determines where and when a gene is active. The genes in operons are transcribed into a single piece of messenger RNA (mRNA).

Since Jacob and Monod first coined the term operon, scientists’ understanding of gene regulation has evolved considerably. Researchers now know, for example, that what was once called “junk” RNA because it wasn’t translated into protein, can nevertheless fulfil important functions. Cossart’s group had previously identified a piece of such non-coding RNA that regulate Listeria’s ability to infect cells, which suggested to them that RNA regulation might be widely exploited by Listeria to aid survival. Cossart and her colleagues decided to map Listeria’s transcriptional program in a systematic way in order to identify as many of those RNA switches as possible.

The biotechnology company Affymetrix built Cossart customized tiling microarrays—that is, arrays of DNA probes that correspond to overlapping stretches of the Listeriagenome. Armed with these arrays, a small army of researchers from Cossart’s and other labs, led by postdoctoral fellow Alejandro Toledo-Arana, compared bacteria grown in the lab with bacteria extracted from the intestine of Listeria-inoculated mice or with bacteria from inoculated samples of human blood. They also compared normal or wild-type bacteria with mutants that had been genetically altered so that they lacked certain known virulence factors.

Their analysis turned up many surprises, one of the biggest of which was how the bacterium’s transcriptome shifts between its soil-dwelling and intestinal modes. “When it arrives in the intestine it turns up the activity of many genes and turns down others, so we see a dramatic reshaping of the transcriptional programme. Strikingly, a series of non-coding RNAs are expressed more often in the intestine or in the blood,” Cossart says. The researchers identified one particular protein, SigB, that controls a series of genes that are needed for Listeria to adapt to the human gut, whereas a different protein, PrfA, switches on genes needed for survival and replication in the blood. By comparing mutant and wild-type bacteria, they identified two non-coding RNAs that appear to contribute to the virulence of L. monocytogenes.

And there were more surprises to come. The researchers found very long untranslated regions (UTRs) of RNA—that is, part of an RNA that is not translated into protein—that overlapped with several genes on the opposite strand and regulated their expression. This was the case, for example, for three genes that are involved in the manufacture of theListeria flagella, the tiny protrusions that allow it to move and find its way in different environments. A known repressor of flagellum synthesis, MogR, turns out to have one very long UTR that spans all three flagellum genes and acts as an antisense RNA, which can block mRNA from being transcribed into a protein

Cossart’s team also identified about 40 riboswitches, RNA structures at the front of genes that act as sensors, stopping translation or expression of the RNA when enough of the gene’s protein product has been made. Some of these riboswitches controlled expression of the gene downstream of them—as had previously been reported—but also the gene upstream. In other words, a riboswitch can extend its influence in both directions, a finding contrary to what anyone had suspected.

These and other regulatory mechanisms will almost certainly turn up in other microorganisms, Cossart says. She believes her group’s paper is likely to be the first of many that will describe, in increasingly minute detail, the complex transcriptional checks and balances that in the case of Listeria make it such a versatile organism.

In the next 10 years, she predicts, the study of bacteria in all their habitats—not just the pathogenic ones—will become a hot topic in research. And the concept of junk in molecular biology will finally be buried, as people realize that when it comes to the genome, nothing is wasted.

Source: http://www.hhmi.org/news/cossart20090517.html

This finding suggests suggests evolutionary biology and virology together can accelerate the discovery of viral-defence mechanisms, according to researchers at Fred Hutchinson Cancer Research Center.

These findings by Julie Kerns, Ph.D., a postdoctoral researcher in the Hutchinson Center’s Basic Science Division, published Jan. 25 in the open-access journal PLoS Genetics, present a striking example by which evolutionary studies can directly lead to biomedically important discoveries in the field of infectious diseases.

The immunity gene, called ZAP, is a key player in a newly discovered branch of antiviral defences in mammals referred to as ‘‘intrinsic immunity.’’ Host proteins like ZAP can target intracellular stages of the viral life cycle to inhibit viral activity. The ZAP gene, first discovered in rats, thwarts a variety of divergent viruses, from retroviruses (like HIV) to alphaviruses (like Sindbis) to filoviruses (like Ebola).

Researchers believe ZAP functions by virtue of its RNAbinding abilities, which recognize specific sequences of the virus and target their viral RNA for destruction. Host-virus interactions are a classic example of genetic conflict in which both entities try to gain an evolutionary advantage over the other. This ‘‘back-and-forth’’ evolution is predicted to result in rapid changes of both host and viral proteins, which
results in an evolutionary signature of positive selection, especially at the direct interaction interface.

“This suggests that we might be able to deduce host-virus conflicts purely by looking at rapidly evolving protein segments,” said Kerns, the lead author of the study, which was conducted in collaboration with senior author Harmit Singh Malik, Ph.D., of the Center’s Basic Sciences Division and also co-author Michael Emerman, Ph.D., of the Center’s Human Biology Division Department.

The researchers found that there has been very little sequence evolution in the RNA-binding domain, which
suggests that human ZAP may be similar to the rat gene in its viral RNA-binding specificity.

Surprisingly, the rapid evolution characteristic of “intrinsic immunity” genes was concentrated in a protein domain that was not even present in the originally discovered rat gene.

The authors found that humans encode two protein versions, or isoforms, from a single ZAP gene: a shorter version similar to the original rat gene and a longer version that possesses a rapidly evolving poly (ADP-ribose) polymerase (PARP)-like domain.

In virological assays, the longer human ZAP protein isoform has higher antiviral activity. Thus, positive selection correctly predicted the more potent antiviral isoform of this protein.

The authors further suggest that ZAP is locked in a conflict with alphaviruses. The discovery of a potential human gene that can restrict alphaviral infection is particularly timely as the mosquito-borne alphavirus, Chikungunya, was responsible for a large epidemic in parts of Southeast Asia in 2006 and is now threatening to invade certain parts of Europe.

The researchers believe that this finding has an enormous implications for the understanding of intrinsic immunity against viruses. This could potentially serve as a guide in the development of antiviral therapeutics.

“We think that a particular alphaviral protein may be playing an evolutionary ‘cat-and-mouse’ game with the ZAP gene,” Malik said. “Identifying this protein could lead to novel ways to tackle diseases caused by alphaviruses.”

Source http://www.fhcrc.org

Researchers say they’ve found that people with atopic dermatitis i.e. eczema, are susceptible to bacterial infections in their skin because their bodies don’t produce enough of two antimicrobial peptides. The findings show that while an allergic reaction can cause a rash, true eczema is all about infection. And medicines containing or inducing the peptides could be used to fight the disorder, which affects millions worldwide.

Eczma patient Lack Natural Antibiotic in Skin
Researchers at National Jewish Medical and Research Center report in the October 10 issue of the New England Journal of Medicine that patients with atopic dermatitis, also known as eczema, are susceptible to bacterial infections of their skin because they fail to produce effective amounts of two antimicrobial peptides. The findings demonstrate for the first time the clinical significance of these peptides in humans, and suggest that a medication containing or inducing the peptides may one day be used to fight the infections that plague millions of atopic dermatitis patients. The accompanying editorial in the journal called it a “seminal study.”

“This study helps explain why 90 percent of atopic dermatitis patients are colonized by staphylococcus aureus and 30 percent develop active infections,” said the study’s senior author, Donald Leung, M.D., Ph.D., Head of Pediatric Allergy-Immunology at National Jewish Medical and Research Center, in Denver. “It is important to understand why people with this common skin disease are so susceptible to skin infections, especially in light of recent widespread concerns that they can develop severe infections after receiving a smallpox vaccination. Interestingly, these antimicrobial peptides are also needed to combat viral infections and therefore could account for the susceptibility of atopic dermatitis patients to eczema vaccinatum and herpes simplex infections.”

Atopic dermatitis is a common, chronic skin disease characterized by dry, itchy and easily irritated skin. It occurs most commonly in infants and young children, but can persist into adulthood. Severe cases can lead to sleep deprivation, chronic bacterial infections, and depression. Approximately one in nine people in the United States suffer from this disease at some point. Along with other allergic diseases, its prevalence has grown significantly in recent years.

Immunologists recently identified peptides in the skin that help fight incipient infections. They rarely appear in normal skin, but are produced in reaction to skin inflammation. Since atopic dermatitis patients are so frequently plagued by bacterial infections, Dr. Leung and his colleagues decided to investigate the potential role of the antimicrobial peptides in those patients.

They evaluated the levels of two antimicrobial peptides, known as LL-37 and HBD-2, in eight patients with moderate to severe atopic dermatitis, 11 psoriasis patients, and six healthy individuals. Psoriasis is an inflammatory skin disease, whose patients rarely suffer skin infections. Microscopic examination of skin samples showed significant amounts of the peptides in the skin of psoriasis patients, but none to minor amounts in skin from atopic dermatitis patients, and none in the skin of healthy controls. Additional analysis indicated that most psoriasis patients had at least 10 times as much of the peptides in their skin as did atopic dermatitis patients. Many atopic dermatitis patients had no detectable amounts of the antimicrobial peptides in their skin.

When the researchers treated staphylococcus aureus colonies with the antimicrobial peptides, levels found in skin of psoriasis patients killed the bacteria. The researchers also found that two hormone-like proteins associated with the immune response and commonly secreted by atopic dermatitis patients’ cells, IL-4 and IL-13, suppressed the production of HBD-2 in cell cultures.

“These findings indicate that atopic dermatitis patients have an impaired immune response that prevents them from producing adequate amounts of antimicrobial peptides in their skin,” said Dr. Leung.

The research suggests that the missing peptides might one day be used as a treatment to prevent skin infections in atopic dermatitis patients.

“Our body normally makes these peptides to fight infections, so there might be fewer side effects than with conventional antibiotics,” said co-author Richard Gallo, M.D., Ph.D., Chief of Dermatology at the Veterans Affairs San Diego Healthcare System and Associate Professor of Medicine at the University of California, San Diego. In 1994, Dr. Gallo was the first to discover the antimicrobial peptides in mammalian skin. The peptides might have another advantage over conventional antibiotics, said Dr. Gallo. While conventional antibiotics attack only bacteria, the antimicrobial peptides fight bacteria, viruses and fungi.

Researchers will also be working in the next several years to alter the immune response of atopic dermatitis patients to promote the production of the antimicrobial peptides, said Dr. Leung.

The findings could shed light on atopic dermatitis patients’ susceptibility to eczema vaccinatum, a widespread skin infection that can afflict those who receive the smallpox vaccination. They may have relevance for other diseases, as well. For instance, it is known that tuberculosis and leprosy patients, whose cells secrete the same immune system regulators as atopic dermatitis patients, are more likely to have disease that spreads widely in their bodies.

The intriguing possibility that a virus which causes cancer in mice could also spread in humans has been raised by laboratory scientists……. again

The Austrian-led team found that mouse mammary tumour virus (MMTV) – which causes breast cancer in the animals – could replicate in human cells.

Other cancer experts, however, said the results, in the journal Retrovirology, should be treated with caution.

They said there was little evidence to link it to human breast cancer.

Viruses are now known to be involved in the development of several cancers – including cervical and liver cancer.

MMTV was discovered in the 1930s, and has been previously suggested as a possible cause of human breast cancer.

However, even though traces of the virus have been found before in human breast cancer cells, attempts to prove a link have foundered in the past because no-one could find evidence that the virus could survive and replicate in that environment.

The latest research claims to have done this – they say MMTV ‘rapidly spreads’ in breast cancer cells in their laboratory.
Dr Stanislave Indik, who led the team, said: “Often, viruses infect cells but cannot replicate further.
“If they can replicate, the chances that they cause disease may be increased.”

The researchers said that while not proving that the virus can cause breast cancer in real people, it “lends more weight” to theories linking the virus to the disease, and to other conditions such as the liver disease primary biliary cirrhosis.

They said that if the MMTV were to be proven, existing drugs such as the anti-HIV medication AZT would stop it replicating.

Other experts are no so convinced that MMTV is likely to be a culprit for the disease.

Epidemiologist Dr Rob Newton, from the charity Cancer Research UK, said: “This paper suggests that, under controlled laboratory conditions, a mouse virus can infect cultured cells derived from human breast tissue.
“It does not demonstrate that this actually happens in the real world, nor have the researchers shown that such infection leads to the development of cancer.

“At the present time, the overall evidence in this area does not support the view that MMTV is a cause of human breast cancer.”

This was echoed by Dr Sarah Cant, from Breakthrough Breast Cancer, who said: “Although this research indicates the mouse mammary tumour virus can spread between breast cancer cells in the lab, there is still no concrete scientific evidence that the virus causes breast cancer in humans.

“Much more research would be needed before we can say whether or not MMTV can be passed from mice to humans to cause breast cancer.”

Peptides previously isolated from hybrid striped bass may be able to control certain viral diseases in fish and humans, suggests new research published in the journal Virology. ”The peptides were highly inhibitory to channel catfish virus, as well as certain amphibian viruses,” said Ed Noga, a co-investigator and North Carolina Sea Grant researcher. The study was led by Greg Chinchar of the University of Mississippi Medical Center.

Peptides Antibiotics From Fish May Fight Viral Diseases, Sea Grant StudyFinds
Peptides previously isolated from hybrid striped bass may be able to control certain viral diseases in fish and humans, suggests new research published in the journal Virology. ”The peptides were highly inhibitory to channel catfish virus, as well as certain amphibian viruses,” said Ed Noga, a co-investigator and North Carolina Sea Grant researcher. The study was led by Greg Chinchar of the University of Mississippi Medical Center.

The peptide antibiotics or ”piscidins,” a name derived from pisces, the Latin word for fish, originally were isolated from mast cells — found in the immune systems of fish and other vertebrates, including humans. ”The results suggest that piscidins may be an important defense for fish against viral infections, which are among the most serious diseases in aquaculture,” added Noga. ”They also have the potential to fight viral infections in humans, particularly the herpes viruses.” Earlier work by other researchers found that viruses can be sensitive to other types of antimicrobial peptides besides piscidins, according to Noga. With the spread of emerging infectious diseases and the growing problem of antibiotic resistance, the search for effective treatments has taken on greater urgency.

In a previous North Carolina Sea Grant study, researchers found that piscidins possessed potent broad-spectrum antibacterial activity, including the ability to fight fish and human pathogens resistant to other antibiotics. This was the first time that researchers had isolated a peptide antibiotic from mast cells of any animals. ”The next step is to determine the specific role that piscidins play in defending fish against viral infections, as well as finding out if piscidins can effectively treat viral disease in an animal model,” Noga said. The study was funded by North Carolina Sea Grant, the National Science Foundation, and the U.S. Department of Agriculture.

Here is a load of crap, pajamas that is designed to protect against MRSA by incorporating silver into its fabric at a level of 2%.

They claim that by having 2% silver woven into its fabric, it can protect against the hospital super bug MRSA. It has already gone on sale UK with M&S the first British retailer to stock the £45 Sleep Safe pajamas and is trialing them at 100 stores.

Silver is known for its infection-fighting properties and silver-laced nightwear has already been tested in a handful of hospitals.

But campaigners called the pajamas a gimmick and said the only way to tackle MRSA was by making hospitals cleaner.

MRSA

MRSA (methicillin resistant Staphylococcus aureus) is a bacterium that can live completely harmlessly on the skin of healthy people but can lead to serious infection.

MRSA infections can cause a broad range of symptoms depending on the part of the body that is infected. These may include surgical wounds, burns, catheter sites, eye, skin and blood.

Dr Mark Enright, a microbiologist at Imperial College London, said that the pajamas would reduce the risk of a patient getting a skin infection that enters a wound.

The problem lies within the hospitals. They are dirty and it should not be up to the public to safeguard themselves

Tony Kitchen of MRSA Support

A spokesman for M&S said: “The fabric that the pajamas are made of has been clinically proven to reduce the risk of MRSA by killing bacteria that come into contact with the fabric.

“Clinical trials are currently ongoing and are three quarters of the way through. The interim results were positive.”

They are only available for men at present and are produced using a fabric which 2% silver has woven into it.

Katherine Murphy, from the Patients’ Association, said: “We welcome the fact these are going on sale, but it shows how desperate the public is.”

However, Tony Kitchen of MRSA Support said: “It sounds like a gimmick – it cannot be a super suit and probably doesn’t make a jot of difference.

“The problem lies within the hospitals. They are dirty and it should not be up to the public to safeguard themselves, it’s the ethos of the hospital that needs to change.”

A spokesman added that if the pajamas did prove effective then they ought to be provided by the health service. rather than paid for by the patient.

Streptococcus throat has become harder to fight using penicillin or amoxicillin, but that’s not because the Streptococci have developed a resistance to those drugs. Instead, more than 50 percent of children have bacteria in their throats that protect strep germs.

New versions of antibiotics called cephalosporins are targeting the other bacteria, improving the odds of successful treatment fivefold.

Strep throat is the second-most-common reason children get antibiotics. But the gold standard antibiotics they get don’t always clear up the infection.

Pediatric infectious disease specialist Michael Pichichero, of the University of Rochester Medical Center in New York, says, says the standard strep drugs — amoxicillin and penicillin — fail in about 25 percent of kids.

“Strep is not actually resistant to penicillin or amoxicillin so, that cannot explain the failures that we’re seeing,” he says.

Instead, other bacteria are the problem. More than half of kids have bacteria in their throats that protect strep germs.

Dr. Pichichero says, “This is very much different from 20 or 30 years ago where almost all children treated with penicillin and amoxicillin would be cured.”

But his research shows newer drugs can kill strep. One in four kids fails treatment with penicillin. One in six fails newer drugs called cephalosporins. Only one in 20 fail the newer versions of those drugs. The newer antibiotics only need to be taken for four to five days, rather than the 10-day course of the older drugs.

BACKGROUND:
Researchers at the University of Rochester Medical Center have found that a short treatment of a newer class of antibiotics is more effective than the traditional 10-day dose of older antibiotics like penicillin and amoxicillin to treat strep throat. The Rochester scientists reviewed over 47 studies over the past 35 years involving more than 11,000 children and found that 25 percent of children treated for strep throat with penicillin ended up back in the doctor’s office within three weeks.

HOW ANTIBIOTICS WORK:
Infections are caused by single-celled organisms called bacteria, which can sometimes evade the body’s immune system and begin reproducing.

Antibiotics kill those harmful bacteria in various ways, such as preventing a bacterium from turning glucose into energy, or preventing it from construct a cell wall. The bacteria die instead of reproducing. Antibiotics are like selective poisons, because they target bacteria and not the body’s own cells.

They are not effective against viruses, however. Unlike bacteria, a virus isn’t a living, reproducing lifeform, just a piece of DBA or RNA. A virus injects its DNA into a living cell and the cell itself reproduces more of the viral DNA. There is nothing to “kill,” so antibiotics don’t work on viruses.

ABOUT STREP THROAT:
Most sore throats are caused by viruses and generally clear up without medical treatment.

Strep throat is an infection caused by a type of bacteria, and thus needs treatment with antibiotics. Symptoms include fever, stomach pain and red swollen tonsils. The bacteria can be transferred to others by sneezing, coughing or shaking hands.

A doctor will usually take a throat culture to test for strep throat. Lack of treatment can lead to other health problems, such as rheumatic fever (which can damage the heart), scarlet fever, blood infections or kidney disease.

DRUG RESISTANCE:
Bacteria are highly adaptive, and over time they naturally develop resistance, protecting them from incoming germs (and antibiotics) and making them harder to kill.

Repeated exposure to penicillin and amoxicillin can result in a throat full of bacteria that can shield strep germs from the older drugs.

The surviving bacteria then reproduce more and become more dominant. Sometimes parents discontinue antibiotic medication prematurely when their children begin to feel better, so the strep germ isn’t entirely killed off, leading to much more severe infections requiring the use of even stronger drugs later on.

North Carolina Sea Grant researchers have isolated a new peptide antibiotic from the American oyster that may have implications for managing many diseases in oysters.

The new antimicrobial peptide “American oyster defensin” (AOD) may protect against bacteria in Crassostrea virginica, a species that is native to North Carolina and important economically to Atlantic and Gulf Coast fisheries.

“This peptide may be helpful in selecting disease-resistant oysters for aquaculture and fisheries and may also allow for the development of a test to monitor oyster health,” says Ed Noga, professor at the North Carolina State University College of Veterinary Medicine.

“In recent years, a number of pathogens, especially bacteria and parasites, have devastated American oyster populations.”

The research findings appear in the new (Dec. 30) issue of Biochemical and Biophysical Research Communications.

Pathogens such as dermo (Perkinsus marinus) have caused major decreases in oyster productivity — bacterial pathogens — such as Vibrio vulnificus that can cause a food-borne illness are a human health concern, according to Noga.

This is the first time that researchers have isolated an antimicrobial peptide from any oyster species, he says.

NC State veterinary medicine postdoctoral research associate Jung-Kil Seo, as well as scientists J. Myron Crawford and Kathryn L. Stone of Yale University’s Keck Biotechnology Resource Laboratory, collaborated with Noga on the study.

“The results may be used to better understand the innate immune system of American oysters and to enhance research to protect it from important microbial infections,” according to Noga.

“Further studies are needed to identify sites of synthesis and storage of AOD and determine mechanisms affecting its regulation.”

Putting bacteria on birth control could stop the spread of drug-resistant microbes, and researchers at the University of North Carolina at Chapel Hill have found a way to do just that.

The team discovered a key weakness in the enzyme that helps “fertile” bacteria swap genes for drug resistance. Drugs called bisphosphonates, widely prescribed for bone loss, block this enzyme and prevent bacteria from spreading antibiotic resistance genes, the research shows. Interfering with the enzyme has the added effect of annihilating antibiotic-resistant bacteria in laboratory cultures. Animal studies of the drugs are now underway.

“Our discoveries may lead to the ability to selectively kill antibiotic-resistant bacteria in patients, and to halt the spread of resistance in clinical settings,” said Matt Redinbo, Ph.D., senior study author and professor of chemistry, biochemistry and biophysics at UNC-Chapel Hill.

The study provides a new weapon in the battle against antibiotic-resistant bacteria, which represent a serious public health problem. In the last decade, almost every type of bacteria has become more resistant to antibiotic treatment. These bugs cause deadly infections that are difficult to treat and expensive to cure.

Every time someone takes an antibiotic, the drug kills the weakest bacteria in the bloodstream. Any bug that has a protective mutation against the antibiotic survives. These drug-resistant microbes quickly accumulate useful mutations and share them with other bacteria through conjugation — the microbe equivalent of mating.

Conjugation starts when two bacteria ‘smoosh’ their membranes together. After each opens a hole in their membrane, one squirts a single strand of DNA to the other. Then the two go on their merry way, one with new genes for traits such as drug resistance. Many highly-drug resistant bacteria rely on an enzyme, called DNA relaxase, to obtain and pass on their resistance genes. A mutation that provides antibiotic resistance can then sweep through a colony as quickly as the latest YouTube hit.

The researchers analyzed relaxase because it plays a crucial role in conjugation. The enzyme starts and stops the movement of DNA between bacteria. “Relaxase is the gatekeeper, and it is also the Achilles’ heel of the resistance process,” Redinbo said.

Led by graduate student Scott Lujan, the team suspected they could block relaxase by searching for vulnerability in a three-dimensional picture of the relaxase protein. Lujan, a biochemistry graduate student in the School of Medicine, confirmed the hunch using x-ray crystallography, which creates nanoscale structural images of the enzyme.

The researchers predicted that the enzyme’s weak link is the spot where it handles DNA. Relaxase must juggle two phosphate-rich DNA strands at the same time. The team suspected a chemical decoy — a phosphate ion — could plug this dual DNA binding site. Redinbo, who has a background in cancer and other disease-related research, realized that bisphosphonates were the right-size decoy.

There are several bisphosphonates on the market; two proved effective. The drugs, called clodronate and etidronate, steal the DNA binding site, preventing relaxase from handling DNA. This wreaks havoc inside E. coli bacteria that are preparing to transfer their genes, the researchers found. Exactly how bisphosphonates destroy each bacterium is still unknown, Redinbo said, but the drugs are potent, wiping out any E. coli carrying relaxase. “That it killed bacteria was a surprise,” he said. By targeting these bacteria, the drugs act like birth control and prevent antibiotic resistance from spreading.

Redinbo, who cautions that the results only apply to E. coli, said further testing will reveal whether bisphosphonates also attack similar species like Acinetobacter baumannii (hospital-acquired pneumonia), Staphylococcus aureus (staph infections) and Burkholderia (lung infections).
“We hope this discovery will help existing antibiotics or offer a new treatment for antibiotic-resistant bacteria,” he said.

The drugs may be most effective at sites where clinicians can best control dosage — on skin and in the gastrointestinal tract, Redinbo said. Other applications may include disinfectants and treatments for farm animals.

Study co-authors, all from UNC-Chapel Hill, include Laura Guogas, Heather Ragonese and Steven Matson. Redinbo is a member of the UNC Lineberger Comprehensive Cancer Center.
Redinbo and his colleagues have filed a patent and formed a small company to further develop the technology.

The study appears online the week of July 9, 2007, in the Proceedings of the National Academy of Sciences. Funding was provided by the National Institutes of Health.

Source

The effort to find preserved samples of the 1918 influenza virus has been a pursuit of both historical and medical importance.

The influenza pandemic in 1918 was the most devastating single disease outbreak in modern history, and examining the virus that caused it may help prepare for, and possibly prevent, future pandemics. When the complete sequence of the 1918 virus was published in 2005, it represented a watershed event for influenza researchers worldwide.

An article in the journal Antiviral Therapy, scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, narrate the story of how scientists discovered samples of the 1918 strain in fixed autopsy tissues and in the body of a woman buried in the Alaskan permafrost.

The article places this discovery in the context of decades of research into the cause of pandemic influenza, and the authors detail the strange convergence of events that allowed them to recover and sequence the virus in the first place. Its genetic material is so fragile that it should not have survived for days, let alone decades.

In a mass grave in a remote Inuit village near the town of Brevig Mission, a large Inuit woman lay buried under more than six feet of ice and dirt for more than 75 years. The permafrost plus the woman’s ample fat stores kept the virus in her lungs so well preserved that when a team of scientists exhumed her body in the late 1990s, they could recover enough viral RNA to sequence the 1918 strain in its whole entirety. This remarkable good fortune enabled these scientists to open a window onto a past pandemic. It could also help mankind gain a foothold for preventing a future one.