Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers map minority microbes in the colon

03.08.2011
They make up less than one-hundredth of 1 percent of the microbes that live in the colon, but the bacteria and archaea that sop up hydrogen in the gut are fundamental to colon health.

In a new study, researchers take a first up close look at these “hydrogenotrophic” microbes, mapping where they live and how abundant they are in different parts of the lower intestine.

The findings are reported in the International Society for Microbial Ecology Journal.

This is the first study to sample these – or any other – microbes at specific locales in the colon, said University of Illinois animal sciences and Institute for Genomic Biology professor Rex Gaskins, who led the research with Carle Foundation gastroenterologist Dr. Eugene Greenberg. These organisms are particularly difficult to get at because they inhabit a thick layer of protective mucous that lines the colon. Previous studies looked only at microbes passed in stool, Gaskins said.

“With those methods, the less abundant taxa were often undetected,” he said. “Little was known about their ecology, or the extent to which the mucosa is colonized and what kind of variation exists.”

This is also the first study to compare the diversity and abundance of colonic microbes in multiple (in this case 25) healthy individuals, he said.

Scientists have known for decades that various microbes in the colon collaborate to ferment undigested food and degrade and dispose of the byproducts of fermentation. (M.P. Bryant, who was an animals sciences professor at Illinois, discovered the first hydrogen-based symbiotic relationship among microbes of the gut in the 1960s.)

Disruptions of the colonic ecosystem can have profound implications for human health, Greenberg said. Although there is a genetic component as well, evidence suggests that inflammatory bowel disease (which includes Crohn’s disease and ulcerative colitis) emerges in response to a microbial imbalance, he said. A study led by Gaskins in 2006 demonstrated for the first time that hydrogen sulfide, a major byproduct of bacterial fermentation in the gut, is genotoxic (damaging to DNA) and may lead to colon cancer.

“We’re getting closer and closer to looking at the microbiological origin of many diseases,” Greenberg said.

To get a better picture of the microbes in colonic mucosa, the researchers analyzed biopsies obtained from healthy subjects during routine colonoscopy exams. They sampled the right (ascending) and left (descending) colon as well as the rectum, then looked for genes that contribute to different hydrogen-consuming metabolic pathways.

The researchers found that all of the subjects harbored three important classes of hydrogen-consuming microbes: methanogens, which convert hydrogen to methane; acetogens, which make acetate from carbon dioxide and hydrogen; and sulfate-reducing bacteria, which expel hydrogen sulfide gas.

Methanogens accounted for about half of the microbes seen in each region of the colon and “become more abundant as you advance toward the rectum,” said postdoctoral researcher Franck Carbonero, an author on the study.

Sulfate-reducing bacteria (SRB) thrive in the presence of sulfate (a byproduct of eating foods such as meat, milk or eggs that have high levels of sulfur-containing amino acids).

The SRB generally outnumbered acetogens in the right colon, Carbonero said, while acetogens were more abundant than SRB in the left colon and rectum.

The researchers found variation among individual study subjects, particularly in the abundance of the three classes of microbes at different biopsy sites. And the team made a surprising discovery when analyzing biopsies taken less than a centimeter apart: microbial diversity can occur even at this small scale.

“These data indicate that if you get down to the scale at which these microbes make their living, perhaps it’s not all the same,” Gaskins said. “We haven’t begun yet to think at that spatial scale.”

The finding is relevant because disease tends to originate in very specific regions of the colon, Greenberg said. Ulcerative colitis starts at the rectum and then proceeds “upriver,” he said. “When you see Crohn’s disease you see an area of involvement, then it’s normal and then you see another area of involvement. And if you do surgery and remove the disease, the disease almost always recurs from the point of removal because – we believe – it’s been reseeded with microbes.”

Future studies will examine the role of hydrogenotrophic microbes in constipation and will look at how diet affects the composition and abundance of microbes in the colon, the researchers said.

The Carle Foundation and the Carle Hospital-University of Illinois Translational Research Program supported this research.

Editor’s notes: To reach Rex Gaskins, call 217- 244-3165; email hgaskins@illinois.edu.

The paper, “Abundance and Diversity of Mucosa-Associated Hydrogenotrophic Microbes in the Healthy Human Colon,” is available online or from the U. of I. News Bureau

Diana Yates | University of Illinois
Further information:
http://www.illinois.edu

More articles from Health and Medicine:

nachricht Using fragment-based approaches to discover new antibiotics
21.06.2018 | SLAS (Society for Laboratory Automation and Screening)

nachricht Scientists learn more about how gene linked to autism affects brain
19.06.2018 | Cincinnati Children's Hospital Medical Center

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>