A recent article in Nature Communications (Benomar 2015) is extremely informative.
Like many good studies, it takes assumed fixtures or mainstays of a field (in this case isolated culturing in microbiology), flips them in some way, and arrives at novel observations and conclusions.
Bacteria have usually been studied in single culture in rich media or in specific starvation conditions. These studies have contributed to understanding and characterizing their metabolism. However, they coexist in nature with other microorganisms and form consortia in which they interact to build an advanced society that drives key biogeochemical cycles.
Briefly, the authors showed co-cultured bacteria (i.e. two different species from the same environment were grown together) formed physical connections with each other to allow one species to harness the other’s unique metabolic chemistry when the former could not survive under the given starvation conditions. In turn, the donor species growth was elevated compared to isolation due to accessing it’s partners’ own metabolites.
The researchers got some great pictures.