A NEW technique devised by researchers from North Carolina State University and the University of Calgary provides a more in-depth look at the metabolism and physiology within microbial communities – the microscopic life such as bacteria, viruses and other tiny forms of life within our bodies and throughout nature. Specifically, the new technique provides a more direct way to determine what food source, or substrate, a certain microbe has consumed.
The researchers use a mass spectrometer to measure with very high accuracy the mass of molecules derived from the microbes in a community.
Then they use a newly developed software programme that allows them to link microbes with their substrates.
The basis for connecting microbe and substrate are so-called carbon stable isotope ratios – the ratios between naturally occurring forms of carbon with different masses.
Nature contains both carbon-12, the most abundant form, and carbon-13, which has one more neutron than carbon-12. Each material has a very specific ratio of these two isotopes, which essentially can be used as the fingerprint or signature of the material.
The new algorithm links the carbon isotope ratios of the substrates that are available to microbes in a given environment to the ratios found in the microbes themselves.