Tag Archives: bacteria

Genes Counter a Bacterial Attack

Gene against bacterial attack unravelled

Humans have an innate defence system against deadly bacteria. However, how the step from gene to anti-bacterial effect occurs in the body is not yet known. To date, B. Pseudomallei, a bacterium suitable for bioweapons, had managed to elude medics. It can remain hidden in the human body for many years without being detected by the immune system. The bacteria can suddenly become activated and spread throughout the body, resulting in the patient dying from blood poisoning. AMC physician Joost Wiersinga and the Laboratory for Experimental Internal Medicine discovered which gene-protein combination renders the lethal bacteria B. pseudomallei harmless.

Wiersinga focussed on the so-called Toll-like receptors. These are the proteins that initiate the fight against pathogens. There are currently ten known Toll-like receptors which are located on the outside of immune cells, our body’s defence system. The toll-like receptors jointly function as a 10-figure alarm code. Upon coming into contact with the immune cell each bacterium enters its own Toll code. For known pathogens this sets off an alarm in the immune system and the defence mechanism is activated. Yet B. pseudomallei fools the system by entering the code of a harmless bacterium. As a result the body’s defence system remains on standby.

Yet some people are resistant: they become infected but not ill. Wiersinga found a genetic cause for this resistance. He discovered which toll receptor can fend off B. pseudomallei. He did this by rearing mice DNA in which the gene for Toll2 production was switched on and off. ‘The group where the gene for Toll2 was switched off, survived the bacterial infection’, says Wiersinga. ‘The other receptor that we investigated, Toll4, had no effect – even though for the past ten years medics had regarded this as the most important receptor.’ The ultimate aim of this study is to develop a vaccine.

PLoS paper: MyD88 Dependent Signaling Contributes to Protective Host Defense against Burkholderia pseudomallei

Yogurts Used to Combat Superbugs

Yoghurts used to combat superbugs

Dieticians at Addenbrooke’s have said evidence suggested the yoghurt might cut the risk of contracting C.diff. Caroline Heyes, dietetic services manager at Addenbrooke’s hospital, said: “Probiotic yoghurts may play a role in preventing C.difficile infection so we have been running a pilot on three of the care of the elderly wards for six months.
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“We can’t say for sure how much of that benefit is down to the yoghurt and how much they are down to a whole range of infection control procedures that the hospital has in place such as the deep cleaning programme, the bare-below-the-elbow programme, and the increased isolation procedures,” Ms Heyes said.

Bacteria and Efficient Food Digestion

Gut Bacteria May Cause And Fight Disease, Obesity

“We’re all sterile until we’re born,” says Glenn Gibson, a microbiologist at the University of Reading in Britain. “We haven’t got anything in us right up until the time we come into this big, bad, dirty world.”

But as soon as we pass out of the birth canal, when we are fetched by a doctor’s hands, placed in a hospital crib, put on our mother’s breast, when we drag a thumb across a blanket and stick that thumb in our mouths, when we swallow our first soft food, we are invaded by all sorts of bacteria. Once inside, they multiply – until the bacteria inside us outnumber our human cells.
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University of Chicago immunologist Alexander Chervonsky, with collaborators from Yale University, recently reported that doses of the right stomach bacteria can stop the development of type 1 diabetes in lab mice. “By changing who is living in our guts, we can prevent type 1 diabetes,” he told The Wall Street Journal.

The bottom line: We now have two sets of genes to think about – the ones we got from our parents and the ones of organisms living inside us. Our parents’ genes we can’t change, but the other set? Now that is one of the newest and most exciting fields in cell biology.

Follow link with related podcast: Gut bacteria may cause and fight, disease, obesity. This whole area of the ecosystem within us and our health I find fascinating. And I fall for confirmation bias on things like becoming inefficient at converting food to energy as a way reduce obesity.

You could have two people sitting down to a bowl of cheerios, they could each eat the same number of cheerios but because of a difference in their gut bacteria one will get more calories than the other.

They then gave an example of the difference being 95 calories versus 99 calories. Hardly seems huge but it would add up. Still that is a less amazing difference than I was expecting.

Copper Doorknobs and Faucets Kill 95% of Superbugs

Copper door handles and taps kill 95% of superbugs in hospitals

A study found that copper fittings rapidly killed bugs on hospital wards, succeeding where other infection control measures failed.
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It is thought the metal ‘suffocates’ germs, preventing them breathing. It may also stop them from feeding and destroy their DNA. Lab tests show that the metal kills off the deadly MRSA and C difficile superbugs. It also kills other dangerous germs, including the flu virus and the E coli food poisoning bug.
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Researcher Professor Peter Lambert, of Aston University, Birmingham, said: ‘The numbers decreased always on copper but not on the steel surfaces.’
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The healing power of copper has been recognised for thousands of years. More than 4,000 years ago, the Egyptians used it to sterilise wounds and drinking water and the Aztecs treated skin conditions with the metal. The ancient Greeks also knew of its benefits. Hippocrates, sometimes called ‘the father of medicine’, noted that it could be used to treat leg ulcers.

NFL Stars no Match for Bacteria

NFL stars no match for bacteria

The problem came to the forefront last week with Cleveland Browns player Kellen Winslow, who recently had his second staph infection. He is reportedly the sixth player to acquire staph among the Browns in five years.
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Peyton Manning of the Indianapolis Colts was revealed to have a staph infection, the Indianapolis Star reported Friday. University of North Carolina-Asheville fans also recently learned that Kenny George, the 7-foot-7 center on the basketball team, had a staph infection complication that led to part of his foot being amputated. It’s unclear how these high-profile athletes acquired their infections, but locker rooms have been found to habor staph bacteria in previous outbreaks.
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A study on the St. Louis Rams published in the New England Journal of Medicine in 2003 found that during the 2003 football season, there were eight MRSA infections among five of the 58 Rams players.

Waste from Gut Bacteria Helps Host Control Weight

A single molecule in the intestinal wall, activated by the waste products from gut bacteria, plays a large role in controlling whether the host animals are lean or fatty, a research team, including scientists from UT Southwestern Medical Center, has found in a mouse study.

When activated, the molecule slows the movement of food through the intestine, allowing the animal to absorb more nutrients and thus gain weight. Without this signal, the animals weigh less.

The study shows that the host can use bacterial byproducts not only as a source of nutrients, but also as chemical signals to regulate body functions. It also points the way to a potential method of controlling weight, the researchers said.

“It’s quite possible that blocking this receptor molecule in the intestine might fight a certain kind of obesity by blocking absorption of energy from the gut,” said Dr. Masashi Yanagisawa, professor of molecular genetics at UT Southwestern and a senior co-author of the study, Proceedings of the National Academy of Sciences, open access: Effects of the gut microbiota on host adiposity are modulated by the short-chain fatty-acid binding G protein-coupled receptor, Gpr41.

Humans, like other animals, have a large and varied population of beneficial bacteria that live in the intestines. The bacteria break up large molecules that the host cannot digest. The host in turn absorbs many of the resulting small molecules for energy and nutrients.

In the Big Fat Lie I mentioned some related ideas:

It also makes perfect sense that our bodies evolved to store energy for worse times (and some of us have bodies better at doing that). Now we are in a new environment where (at least for many people alive today) finding enough calories is not going to be a problem so it would be nice if we could tell our bodies to get less efficient at storing fat

This research seems to be looking for a similar way to attack the obesity epidemic: reduce the efficiency of our bodies converting potential energy in the food we eat to energy we use or store. If we can make that part of the solution that will be nice. So far the reduction in our activity and increase in food intake have not been getting good results. And efforts to increase (from our current low levels) activity and reduce food intake have not been very effective.
Continue reading →

Plants can Signal Microbial Friends for Help

When under attack, plants can signal microbial friends for help

Researchers at the University of Delaware have discovered that when the leaf of a plant is under attack by a pathogen, it can send out an S.O.S. to the roots for help, and the roots will respond by secreting an acid that brings beneficial bacteria to the rescue.
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In a series of laboratory experiments, the scientists infected the leaves of the small flowering plant Arabidopsis thaliana with a pathogenic bacterium, Pseudomonas syringae. Within a few days, the leaves of the infected plants began yellowing and showing other symptoms of disease.

However, the infected plants whose roots had been inoculated with the beneficial microbe Bacillus subtilis were perfectly healthy. Farmers often add B. subtilis to the soil to boost plant immunity. It forms a protective biofilm around plant roots and also has antimicrobial properties, according to Bais.

Using molecular biological tools, the scientists detected the transmission of a long-distance signal, a “call for help,” from the leaves to the roots in the plants that had Bacillus in the soil. The roots responded by secreting a carbon-rich chemical–malic acid.

All plants biosynthesize malic acid, Bais explains, but only under specific conditions and for a specific purpose–in this case, the chemical was actively secreted to attract Bacillus. Magnified images of the roots and leaves showed the ratcheted-up defense response provided by the beneficial microorganisms.
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“Plants can’t move from where they are, so the only way they can accrue good neighbors is through chemistry,” Bais notes.

Silk E.coli Sensors

“Edible Optics” Could Make Food Safer

Scientists at Tufts University’s School of Engineering have demonstrated for the first time that it is possible to design such “living” optical elements that could enable an entirely new class of sensors. These sensors would combine sophisticated nanoscale optics with biological readout functions, be biocompatible and biodegradable, and be manufactured and stored at room temperatures without use of toxic chemicals. The Tufts team used fibers from silkworms to develop the platform devices.
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The possibility of integrating optical readout and biological function in a single biocompatible device unconstrained by these limitations is tantalizing. Silk optics has captured the interest of the Defense Department, which has funded and been instrumental in enabling rapid progress on the topic. The Defense Advanced Research Projects Agency (DARPA) awarded Tufts a research contract in 2007 and is funding Tufts and others on groundbreaking projects that could someday result in biodegradable optical sensing communications technology.
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To form the devices, Tufts scientists boiled cocoons of the Bombyx mori silkworm in a water solution and extracted the glue-like sericin proteins. The purified silk protein solution was ultimately poured onto negative molds of ruled and holographic diffraction gratings with spacing as fine as 3600 grooves/mm.
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The Tufts team embedded three very different biological agents in the silk solution: a protein (hemoglobin), an enzyme (horseradish peroxidase) and an organic pH indicator (phenol red). In the hardened silk optical element, all three agents maintained their activity for long periods when simply stored on a shelf. “We have optical devices embedded with enzymes that are still active after almost a year of storage at room temperature.

Foreign Cells Outnumber Human Cells in Our Bodies

This is one of those area I find very interesting: People Have More Bacterial Cells than Human Cells. Colin Nickerson has written an interesting article on the topic: Of microbes and men

Scientists estimate that 90 percent of the cells contained in the human body belong to nonhuman organisms – mostly bacteria, but also a smattering of fungi and other eensy entities. Some 100 trillion microbes nestle in niches from our teeth to our toes.

But what’s setting science on its heels these days is not the boggling numbers of bugs so much as the budding recognition that they are much more than casual hitchhikers capable of causing disease. They may be so essential to well-being that humans couldn’t live without them.

In this emerging view, humans and their microbes – or, as some biologists playfully put it, microbes and their attached humans – have evolved together to form an extraordinarily complex ecosystem.

The understanding of the complex interaction is something I came to through reading on the overuse of antibiotics. And the more I read the more interesting it gets.

“We can’t take nutrition properly without bacteria. We can’t fight bad germs without good germs,” he said. “It may turn out that secretions from bacteria affect not only long-term health, but hour-by-hour moods – could a person’s happiness depend on his or her bugs? It’s possible. Our existences are so incredibly intertwined.”

However, in the opinion of some researchers, this strange union may be headed for trouble because of profligate use of antibiotics and antiseptic lifestyles that deter the transfer of vital strains of bacteria that have swarmed in our systems at least since early humans ventured out of Africa.

Move over MRSA, C.diff is Here

Clostridium difficile (C.diff), a bacteria, is increasingly posing health risk. Rising Foe Defies Hospitals’ War On ‘Superbugs’

Even as hospitals begin to get control of other drug-resistant infections such as MRSA, a form of staph, rates of C. diff are rising sharply, and a recent, more virulent strain of the bug is causing more severe complications. The Centers for Disease Control and Prevention estimates there are 500,000 cases of C. diff infection annually in the U.S., contributing to between 15,000 and 30,000 deaths. That’s up from roughly 150,000 cases in 2001.
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Many patients get C. diff infections as an unintended consequence of taking antibiotics for other illnesses. That’s because bacteria normally found in a person’s intestines help keep C. diff under control, allowing the bug to live in the gut without necessarily causing illness. But when a person takes antibiotics, both bad and good bacteria are suppressed, allowing drug-resistant C. diff to grow out of control.
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Only 3% to 5% of healthy, non-hospitalized adults carry C. diff in their gut, but that rate is much higher in hospitals and nursing homes, where carriers can spread the bacteria to others. Studies at several hospitals in recent years have shown that 20% or more of inpatients were colonized with C. diff, and a 2007 study of 73 long-term-care residents showed 55% were positive for C. diff. Even though the majority had no symptoms of disease, spores on the skin of asymptomatic patients were easily transferred to the investigators’ hands.