05:45pm Thursday 04 June 2020

Beer and bread yeast-eating bacteria aid human health

Led by Newcastle University, UK, and the University of Michigan, the study shows how microbes in our digestive tract have learned to unravel the difficult to break down complex carbohydrates that make up the yeast cell wall.

Evolving over the 7,000 years humans have consumed fermented food and drink, the ability of strains of Bacteroides thetaiotomicron (Bt) to degrade yeasts is almost exclusively found in the human gut.

Publishing their findings today in Nature, the international research team say the discovery of this process could accelerate the development of prebiotic medicines to help people suffering from bowel problems and autoimmune diseases.

The study, led by Professor Harry Gilbert at Newcastle University, Professor Eric Martens, of the University of Michigan, and Dr Wade Abbott of Agriculture and Agri-Food Canada, has identified the complex machinery that targets yeast carbohydrates.

This has provided a better understanding of how our unique intestinal soup of bacteria – termed the microbiome – has the capacity to obtain nutrients from our highly varied diet.

“People are very interested in developing dietary regimes where good bacteria are of benefit,” explained Professor Gilbert.

“When you have certain bacteria dominant in the gut these microorganisms can produce molecules which have health promoting effects.

“There’s a lot of interest in developing prebiotics. The more you understand about how complex glycans are degraded the more you can think about developing sophisticated prebiotics that target the growth of specific beneficial bacteria.”

The research involving scientists from Newcastle, Australia, Canada, USA and Belgium has unraveled the mechanism by which Bt, a dominant member of the human microbiome, has learned to feast upon difficult to break down complex carbohydrates called yeast mannans.

Mannans, derived from the yeast cell wall, are a component in our diet from fermented foods including bread, beer, wine and soy sauce.

It is hoped the research could aid a better understanding of how to provide nutrients to specific organisms in the microbiome. Indeed, given that Bt has been granted Orphan Designation by the FDA for Paediatric Crohn’s Disease (ThetanixTM), yeast mannan may have health promoting effects on the microbiome by stimulating the growth of Bt.

Professor Gideon Davies, of York Structural Biology Laboratory at the University of York, who contributed to the work, said: “The ability of Bacteroides thetaiotaomicron to degrade yeast cell wall components may be of importance in fighting off yeast infections and in autoimmune diseases such as Crohn’s disease.”

Professor Spencer Williams, of the University of Melbourne, who also contributed to the research added: “Bacteroides thetaiotaomicron is an important part of our microbiota, the community of bacteria that live within us.

“By consuming carbohydrates that we can’t, which they convert to short-chain fatty acids that they secrete into our distal gut, these bacteria establish a symbiosis that nourishes the cells that line our gut wall and provide important immune signals that establish a healthy immune response.”

The research team consisted of: The Institute for Cell and Molecular Biosciences at Newcastle University, the Complex Carbohydrate Research Centre at the University of Georgia, the Department of Microbiology and Immunology at the University of Michigan Medical School, the Department of Chemistry at the University of York, the School of Chemistry and Bio21 Molecular Science and Biotechnology Institute at the University of Melbourne, the Department of Pharmaceutical Chemistry at the University of Kansas School of Pharmacy, Oxyrane, Ghent, Agriculture and Agri-Food Canada, Biochemistry and Microbiology, University of Victoria, Canada and the USDA, Agricultural Research Service, National Laboratory for Agriculture and the Environment, Iowa.

Source Information: ‘Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism’. Harry Gilbert et al. Nature www.nature.com 



Key Facts:

  • Newcastle University is a Russell Group University
  • Ranked in the top 1% of universities in the world (QS World University Rankings 2014)
  • Ranked 16th in the UK for global research power (REF 2014)
  • Ranked 22nd in The Sunday Times 2015 Good University Guide
  • Amongst our peers Newcastle is:
    • Joint 6th in the UK for student satisfaction
    • Ranked 8th in the UK for Medical and Life Sciences research quality (REF 2014)
    • Ranked 3rd in the UK for English, and in the top 12 for Geography, Architecture and Planning, and Cultural and Media Studies research quality
    • Engineering and Physical Sciences Research Council (EPSRC) top 20 strategic partner
  • 93.7% of our students are in a job or further training within six months of graduating
  • We have a world-class reputation for research excellence and are spearheading three major societal challenges that have a significant impact on global society. These themes are: Ageing, Sustainability, and Social Renewal
  • Newcastle University is the first UK university to establish a fully owned international branch campus for medicine at its NUMed Campus in Malaysia which opened in 2011
  • Our international students put Newcastle University in the world’s top 50 (ISB 2013) of global universities.
  • Newcastle University Business School is one of 20 Triple Accredited Business Schools in the UK

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