Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gut bacteria promote obesity in mice

30.09.2014

A species of gut bacteria called Clostridium ramosum, coupled with a high-fat diet, may cause animals to gain weight. The work is published this week in mBio®, the online open-access journal of the American Society for Microbiology.

A research team from the German Institute of Human Nutrition Potsdam-Rehbruecke in Nuthetal observed that mice harboring human gut bacteria including C. ramosum gained weight when fed a high-fat diet. Mice that did not have C. ramosum were less obese even when consuming a high-fat diet, and mice that had C. ramosum but consumed a low-fat diet also stayed lean.


Clostridium ramosum

Previous studies have found C. ramosum and other representatives of the Erysipelotrichi class in obese humans, said senior study author Michael Blaut, PhD, head of the institute's Department of Gastrointestinal Microbiology. This suggests that growth of this organism in the digestive tract is stimulated by high-fat diets, which in turn improves nutrient uptake and enhances the effect of such diets on body weight and body fat.

"We were surprised that presence or absence of one species in a defined bacterial community affected body weight and body fat development in mice," says Blaut.

Blaut and colleagues investigated the role of C. ramosum in three groups of mice: some harbored a simplified human intestinal microbiota (bacteria) of eight bacterial species including C. ramosum; some had simplified human intestinal microbiota except for C. ramosum, and some had C. ramosum only. The researchers called the first group SIHUMI, the second group SIHUMIw/oCra and the third group Cra. Mice were fed either a high-fat diet or low-fat diet for four weeks.

After four weeks eating a high-fat diet, the mouse groups did not differ in energy intake, diet digestibility, and selected markers of low-grade inflammation. However, SIHUMI mice and Cra mice fed a high-fat diet gained significantly more body weight and body fat, which implies that they converted food more efficiently to energy than did the SIHUMIw/oCra mice. By contrast, all groups of mice fed a low-fat diet stayed lean, indicating that the obesity effect of C. ramosum only occurred on high-fat diets.

The obese SIHUMI and Cra mice also had higher gene expression of glucose transporter 2 (Glut2), a protein that enables absorption of glucose and fructose, and fat transport proteins including fatty acid translocase (Cd36).

"Our results indicate that Clostridium ramosum improves nutrient uptake in the small intestine and thereby promotes obesity," Blaut said. Associations between obesity and increased levels of lipopolysaccharides (components of the cell wall of gram-negative bacteria) causing inflammation, or increased formation of molecules called short chain fatty acids, reported by other researchers, were not found in this study, he said: "This possibly means that there is more than one mechanism underlying the promotion of obesity by intestinal bacteria."

Through additional studies Blaut said he hopes to learn more about how C. ramosum affects its host's energy metabolism and whether similar results occur in conventional mice given the bacteria. "Unraveling the underlying mechanism may help to develop new strategies in the prevention or treatment of obesity," he said.

###

The current study was supported by the German Institute of Human Nutrition Potsdam-Rehbruecke.

mBio® is an open access online journal published by the American Society for Microbiology to make microbiology research broadly accessible. The focus of the journal is on rapid publication of cutting-edge research spanning the entire spectrum of microbiology and related fields. It can be found online at http://mbio.asm.org.

The American Society for Microbiology is the largest single life science society, composed of over 39,000 scientists and health professionals. ASM's mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.

Jim Sliwa | Eurek Alert!

More articles from Life Sciences:

nachricht Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg

nachricht Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>