- Can cannibalism fight infections?
- Scientists drill holes through deadly bacteria's Kevlar-like hide
- Nanoemulsion potent against superbugs that kill cystic fibrosis patients
- Nanotechnology used to probe effectiveness of antibiotics
Can cannibalism fight infections?February 2nd, 2009
The secret weapon against a colony of bacteria may be to stress it with its own protection system, which forces it to reduce its population through cannibalism.
"Our studies suggest this is a new way to fight off bacteria," says Prof. Eshel Ben-Jacob, an award-winning scientist from Tel Aviv University's School of Physics and Astronomy. "If we expose the entire colony to the very same chemical signals that the bacteria produce to fend off competition, they'll do the work for us and kill each other."
Cannibalism among bacteria, explains Prof. Ben-Jacob, is a strange cooperative behavior elicited under stress. In response to stressors such as starvation, heat shock and harmful chemicals, the bacteria reduce their population with a chemical that kills sister cells in the colony.
"But what's most interesting among bacteria is that they appear to develop a rudimentary form of social intelligence, reflected in a sophisticated and delicate chemical dialogue conducted to guarantee that only a fraction of the cells are killed."
In the current study, the researchers investigated what happens when two sibling colonies of bacteria --Paenibacillus dendritiformis (a special strain of social bacteria discovered by Prof. Ben-Jacob) -- are grown side by side on a hard surface with limited nutrients. Surprisingly, the two colonies not only inhibited each other from growing into the territory between them but induced the death of those cells close to the border, researchers found.
Even more interesting to the scientists was the discovery that cell death stopped when they blocked the exchange of chemical messages between the two colonies. "It looks as if a message from one colony initiates population reduction in the cells across the gap." says Prof. Ben-Jacob.
Bacteria, Prof. Ben-Jacob says, know how to glean information from the environment, talk with each other, distribute tasks and generate collective memory. He believes that bacterial social intelligence, conveyed through advanced chemical language, allows bacteria to turn their colonies into massive "brains" that process information, learning from past experience to solve unfamiliar problems and better cope with new challenges.source
My comment: Awesome! I never knew that bacteria are so social and intelligent. From one point of view, I hate bacteria, because I have too often confrontation with them. But from another- I admire them. They are so tough and adaptive and versatile. And surprisingly intelligent for something so small. Maybe the size really doesn't matter.
Scientists drill holes through deadly bacteria's Kevlar-like hideIn research published in the Proceedings of the National Academy of Sciences, Rockefeller University researchers have figured out how to drill holes through the Kevlar-like hide of gram-positive bacteria without obliterating them, and in doing so, they’ve made it possible to study, from the inside out, most of the known bacteria on the planet.
The work, led by Vincent A. Fischetti, head of the Laboratory of Bacterial Pathogenesis and Immunology, provides, for the first time ever, a look inside the rapidly multiplying and highly contagious Streptococcus pyogenes, the culprit behind a myriad of diseases, including strep throat and rheumatic fever. At a time when organisms are increasingly acquiring “superbug” powers, Fischetti and his colleague Assaf Raz, a graduate student in the lab, have used the technique to look specifically at a well-known enzyme called sortase A and its distribution inside the cell. Common to all gram-positive bacteria, the enzyme functions by anchoring surface proteins to the cell wall, endowing the bacteria with their infectious properties.
“If you interfere with this process, you get naked bacteria and naked bacteria are unable to cause infection,” says Fischetti. “So the idea here is that the more we know how sortase functions inside the cell, the more strategies we’ll have to interfere with its activity stripping the bacteria of their pathogenic surface proteins.”
The technique relies on enzymes produced by viruses, called bacteriophages, which attack only bacteria. Unlike antibiotics, which take time to take effect, phage enzymes strike with blitzkrieg speed, preventing bacteria from mustering a defense. Usually, these enzymes destroy their target, leaving nothing but cellular debris behind. That’s because the pressure inside a bacterium is like a champagne bottle: Once it’s opened, it explodes. In their work, however, Fischetti and Raz figured out how to poke holes in S. pyogenes while keeping the bacteria intact. These holes provide an entryway for tags that fluoresce when they attach to molecules inside the altered bacteria, allowing scientists to visualize, from the inside out, what makes these single-celled powerhouses infectious.
Fischetti and Raz were interested in whether the distribution of sortase A inside the cell affects the distribution of protein M, one of many surface proteins found on these bacteria. The researchers found that as the bacteria divide, the tagged sortase A assembles at a very specific location: the point of cell division where it anchors protein M. Interestingly, before the bacterium finishes dividing, sortase A starts to assemble at the new point of division — even before the recently formed bacteria starts dividing.
Perhaps this migration is a way for bacteria to be ultra-organized. “Strep divide every 20 or 30 minutes under optimal conditions,” says Fischetti. “During that time, a lot of things are going on and the bug has to be extremely organized for all these things to happen very quickly. We now have the tools to start answering how these organisms carry out this feat. ” source
My comment: Cool! Even if somewhat long. Bacteria are just so cool! Ok, maybe it's not so cool to read about those resistant bacteria, but this new technology looks promising. Maybe they'll finally find something to kill the bugs in us once and for all. At lease the bad ones.
Nanoemulsion potent against superbugs that kill cystic fibrosis patientsFebruary 4th, 2009
University of Michigan scientists report highly encouraging evidence that a super-fine oil-and-water emulsion, already shown to kill many other microbes, may be able to quell the ravaging, often drug-resistant infections that cause nearly all cystic fibrosis deaths.
Cystic fibrosis is an inherited chronic lung disease that affects 30,000 children and adults in the United States. Patients have mucus-clogged lungs that leave them vulnerable to repeated, ever more serious respiratory infections.
Nanoemulsions developed at Baker's institute consist of soybean oil, water, alcohol and surfactants forced by high-stress mechanical extrusion into droplets less than 400 nanometers in size.
These emulsions have already proved to be non-toxic, potent killers of bacteria such as Streptococcus pneumoniae, H. influenzae and gonorrhea, of viruses such as herpes simplex and influenza A, and of several fungi. Nanoemulsion treatments for cold sores and toenail fungus are in Phase 3 clinical trials.
"We have a product that looks like it could be safely administered to the lungs of people with cystic fibrosis," LiPuma says. If future trials show that patients can tolerate effective doses of the nanoemulsion, he adds, "This could be a major breakthrough in the treatment of cystic fibrosis."
The novel physical mode of action -- the nanoemulsion appears to kill bacteria by disrupting their outer membranes - makes developing resistance unlikely, LiPuma says.
"Given that this technology works differently from antibiotic drugs, it provides a potential alternative for treatment in antibiotic-resistant bacteria. Since the material has already shown success in treating skin infections, we believe it has potential to treat antibiotic-resistant lung infections," says Baker.If the technique proves safe and effective, people would inhale the nanoemulsion using a nebulizer and be able to reduce the severity and frequency of infections that spiral out of control due to resistance to current antibiotics.
In cell cultures in the lab, the U-M scientists tested a nanoemulsion against 150 bacterial strains that attack cystic fibrosis patients. The emulsion proved effective at killing all of them, including one-third that are resistant to many antibiotics and 13 percent that resist all antibiotics.
They then tested the nanoemulsion against several bacterial strains grown in biofilms and sputum, to more closely simulate conditions in a patient's body. Antibiotics often can't penetrate biofilms and sputum unless given at high doses with unacceptable side effects.
"We saw, not surprisingly, that greater concentrations of nanoemulsion were required to kill the bacteria, but we saw no strains that were resistant," LiPuma says. Whether humans can tolerate those concentrations well remains to be seen.
The University of Michigan has filed for patent protection on the CF nanoemulsion, and licensed this technology to Ann Arbor-based NanoBio Corporation. Baker is a founder and equity holder of NanoBio. source
My comment: NICE! Ok, that's extremely good news and it surprisingly reminds me of alchemy. I mean, on first glance the emulsion is nothing special. But it obviously does work! If it's also safe, this will be the greatest discovery ever. Also, I like it that the scientists filed a patent and founded a company. Way to go, guys!
Nanotechnology used to probe effectiveness of antibioticsFebruary 4th, 2009
A group of researchers led by scientists from the London Centre for Nanotechnology, in collaboration with a University of Queensland researcher, have discovered a way of using tiny nano-probes to help understand how an antibiotic is effective against bacteria.
Bacteria such as MRSA (commonly known as Golden Staph) are becoming increasingly resistant to antibiotics, posing a major community health problem.
Professor Matt Cooper, the Australian in the team, has this week joined the Institute for Molecular Bioscience at UQ on a $4 million Australia Fellowship.
Through the fellowship, he will establish a research program in the development of antibiotics and antifungals that are active against drug-resistant pathogens, in particular those responsible for hospital-acquired infections.
To study antibiotic action, the London team made nano-probes coated with molecules found in bacterial cell walls from normal bacteria and bacteria resistant to antibiotics.
They then added doses of the “last resort” antibiotic, vancomycin, to the system and found that probes from normal bacteria were stressed and changed shape, whereas probes from resistant bacteria were only weakly affected. These bent probes could be detected with a laser, indicating that the antibiotic was applying a force to the surface.
This allowed the researchers to quickly assess the effectiveness of an antibiotic and propose new ways in which antibiotics may be acting to cause the bacteria to burst and die.
The system was able to detect that it is 1,000 times harder for vancomycin to attach to resistant bacteria than to non-resistant bacteria.
The team are now screening other novel antibiotics with the goal of finding a drug that is able to bind strongly to resistant bacteria and cause substantial structural weaknesses to the cell wall. source
My comment: One more cool result. Thogh, this article is more oriented to the future, still, they found a way to measure the effect of antibiotic on a bacteria. That's important result.