[{"Bold_text": "plural noun", "List Items": ["ubiquitous one-celled organisms, spherical, spiral, or rod-shaped and appearing singly or in chains, comprising numerous and variously classified phyla: among the inestimable number of species are those involved in fermentation, putrefaction, infectious diseases, and nitrogen fixation."]}, {"Bold_text": "noun", "List Items": ["(in the three-domain system of classification) the taxonomic domain comprising the bacteria ."]}]