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Just as there are blood group, three “enterotypes” or intestinal bacterial signatures have been identified by researchers at the European consortium MetaHIT, coordinated by INRA and involving researchers from INRA, CEA, CNRS and University of Evry-Val d’Essonne, as well as those of Danone and the Merieux Institute.
These signatures were independent of geographic origin of an individual’s age or health status. They are mainly determined by the abundance of certain types of bacteria but also by their genetic potential (that is to say by the functions that their genes encode). This research, opening many potential applications in the field of nutrition and human health. All of these results is published in the online edition of the journal Nature Advanced dated April 20, 2011.
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Populations of bacteria and their viruses experience in natural conditions, a reciprocal evolution. This was revealed by a Spanish-British investigation left open the door for the creation of “antibiotics evolved” for therapeutic uses.
“Working with bacteria and viruses in soil has allowed us to observe in action the co-evolution between host and parasite, and serves as a bridge between theory and the natural world,” he told SINC Pedro Gomez, lead study author and researcher at the Center Soil Science and Applied Biology Segura (CEBAS-CSIC), currently working at the University of Oxford (United Kingdom).
The study, published today Science, demonstrates for the first time that populations of bacteria and their viruses (phages) experience in natural conditions, a reciprocal evolution in terms of resistance and infection. So far, this behavior had never been seen directly.
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Identified dell’antitossina structure that allows the bacteria not to suffer the damage caused by toxins produced
Many bacteria produce toxins that attack and damage or destroy cells that harbor them. To avoid this weapon strikes even those who produced it, they exploit different strategies, often simultaneously producing protective antitoxin.
Now a team of researchers at Washington University School of Medicine in St. Louis was able to determine the structure of the toxin and dell’antitossina in S treptococcus pyogenes , a bacterium that is widespread cause a variety of ailments, from joint pain throat with rheumatic fever.
The discovery opens the door to the possibility of designing a new class of antibiotics that exploit the toxin to destroy the bacteria itself.
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Scientists from Masaryk University [1] are conducting a unique research on bacteria, going against conventional wisdom. They can distinguish more types of microorganisms and quickly separate those who are dangerous from those that are beneficial. They are now even possible to detect bacteria that are resistant to drugs.
Few would have weighed the idea of protein in bacteria to determine whether they are harmful or not. Yet in this way that are committed Ondrej Sedo [2] Institute of Experimental Biology [3] Faculty of Sciences [4], Masaryk University and his team. The paradox is that bacteria, or at least “good” bacteria, could save the lives of people with serious diseases. According Ondrej Sedo, whose work is done in collaboration with German colleagues, life and the world of bacteria are much more complex than we previously thought.
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A strain of bifidobacteria prevents the development of deadly food infection in mice.
Of the 100,000 billion bacteria belonging to more than 1000 species that frolic in our digestive tract (large bowel and terminal segment of the small intestine), E. coli (Escherichia coli) is common (see Focus on our gut bacteria “For Science, March 2010). But some of its stem, called enterohaemorrhagic (EHEC), are toxic and cause each year hundreds of thousands of diarrhea through contaminated food products (meat undercooked, raw milk, etc.).. Evolve a few thousand cases in severe life-threatening (hemorrhagic colitis and hemolytic uremic syndrome).
However, according to several studies in mice, certain bacteria called probiotics (beneficial for health if ingested live in adequate amounts), bifidobacteria, appear to protect against the worsening of infections caused by EHEC, including acid-producing acetic acid (acetate). Shinji Fukada and colleagues at the University of Yokohama, Japan, just to clarify this protective mechanism: acetate stimulate anti-inflammatory defenses of intestinal cells and block the passage of the toxin secreted by EHEC in the blood. After work team Sarkis Mazmanian, in 2008, the anti-inflammatory effect of bacteria Bacteroides fragilisIs one of the first studies to decipher a mechanism of action of probiotic bacteria, says Philippe Langella, Research Unit of Ecology and digestive physiology of the INRA in Jouy-en-Josas.
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Swimming, microalgae create turbulence more complex than expected.
Plankton, bacteria, algae, protozoa: many microorganisms inhabit the seas, lakes or even our intestines. Everyone, moving – usually with one or more flagella – creates currents that influence the movements of its congeners, sometimes to the point of synchronization. Far from trivial, collective motions thus generated play an important role in the survival and growth of settlements, facilitating access to nutrients and oxygen in the oceans, including the mixing produced by plankton and microalgae promote the absorption of carbon dioxide by marine phytoplankton production and oxygen that results.
If physics describes propel a microorganism in a fluid, little is known about how the movements of each micro-organism generate collective behavior. By measuring the currents produced by videomicroscopy by microalgae in motion, two independent teams have found that the influence of a microorganism on its environment was more complex than previously thought.
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The way we expand the colonies of bacteria is one of the classic subjects of study of biology. In a recent paper by Ignacio Pagonabarraga , Professor, Department of Fundamental Physics at the UB, in collaboration with researchers from the University of Edinburgh , we propose a new model that allows, with only two parameters , reproduce the growth patterns of colonies of these microorganisms.
In the mathematical model developed in this work , published in the journal Proceedings of the National Academy of Science (PNAS ) , have been taken into account the basic movements of bacteria , which are motility, directional movement and dissemination, more disordered motion score. “In the end we have identified two dimensional parameters that describe how motility changes in terms of different aspects such as the density of bacteria or the rate of spread , ” explains researcher Pagonabarraga . Currently, to study the growth of the colonies models consider the joint evolution of the density of bacteria and chemical stimulants where you have to fit a significant number of up to ten parameters.
In nature , bacteria are often concentrated in areas forming spectacular structures seen by the microscope. In the laboratory , it is possible to reproduce these patterns in a Petri dish containing agar gel that makes food. In this context, mathematical biologists have developed a series of equations that take into account how the bacteria move in terms of food , a phenomenon called chemotaxis. Thus, ” in the proposed model has not been taken into account chemotaxis but predicted the formation of strikingly similar patterns to those who are considered as a result of chemotactic behavior , ” concludes Pagonabarraga . Furthermore, the two parameters have physical meaning and it would adjust to the design of future experiments.
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Cleaning products used in homes and in commercial or agricultural facilities, could be contributing to increasing antimicrobial resistance and foodborne pathogen Salmonella. This is a disturbing finding that has made a team of scientists from the University of Birmingham.
The study authors recommend a drastic reduction in the use “frivolous” of biocides, especially in household products, to ensure that the number of resistant bacterial strains does not increase.
Biocides are chemicals that kill pathogenic bacteria (disease causing) and are commonly used in hospitals, farms, manufacturing establishments or food processing, and increasingly at home, to eradicate bacteria and prevent potential sources of infection. The increased use of biocides in household products has led to the accumulation and persistence of some of them in the environment. It is this persistence that interests Dr. Mark Webber and his team.
The use of biocides is desirable in many places and situations, but the increasing accumulation in the environment can lead to bacteria that are repeatedly exposed to them at low concentrations.
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The bacterial biofilms, bacteria assembled into a tough film, are the bane of medical institutions. Researchers in the United States have identified molecules that trigger the collapse of these biofilms.
Most bacteria are gregarious. By multiplying, they assemble into a thin film resistance – a biofilm – which gradually covered the surface they have invested, whether that of a standing water, rocks, walls your shower, your contact lenses or … your teeth. These biofilms have a limited life: when nutrients are lacking and that the waste becomes too abundant, the film breaks down and bacteria regained their freedom.
Researchers at Harvard University, United States, recently proposed a strategy to destroy biofilms formed by bacteria of the species Bacillus subtilis. It is to provide a cocktail of bacteria to amino acids that not only prevents the formation of a biofilm, but it divides the existing biofilms.
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Imagine a little. A robotic mission returned from Mars. The news comes: some samples are bacteria living there life on Mars! View of the mind? Not so sure: except that, it is conceivable that one day enthuses about the presence of bacteria on Mars land … made by a spacecraft!
This fiction, underscores the issue of contamination of spacecraft by Earth bacteria, our Escherichia coli other Streptococcus aureus must be taken seriously. Ecology is also space! Because we can not exclude contaminating a planet like Mars, U.S. researchers confirm (1). They have submitted two families of bacteria E.coli and Serratia liquefaciens simulated conditions of life on the surface of March: reconstruction of the atmosphere, the surface chemistry of the soil, ultraviolet radiation, the alternation of daytime temperature (20 ° C and -50 ° C) … Verdict, the bacteria could not possibly grow, but they are able to withstand the Martian environment, provided they are sheltered from ultraviolet radiation. In a hiding place that would display on the spacecraft, or a bit of dust on the surface of Mars.
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Of the 100,000 billion bacteria belonging to more than 1000 species that frolic in our digestive tract (large bowel and terminal segment of the small intestine), E. coli (Escherichia coli) is common (see Focus on our gut bacteria “For Science, March 2010). But some of its stem, called enterohaemorrhagic (EHEC), are toxic and cause each year hundreds of thousands of diarrhea through contaminated food products (meat undercooked, raw milk, etc.).. Evolve a few thousand cases in severe life-threatening (hemorrhagic colitis and hemolytic uremic syndrome).
Plankton, bacteria, algae, protozoa: many microorganisms inhabit the seas, lakes or even our intestines. Everyone, moving – usually with one or more flagella – creates currents that influence the movements of its congeners, sometimes to the point of synchronization. Far from trivial, collective motions thus generated play an important role in the survival and growth of settlements, facilitating access to nutrients and oxygen in the oceans, including the mixing produced by plankton and microalgae promote the absorption of carbon dioxide by marine phytoplankton production and oxygen that results.