In order to study the gut microbiome of humans, scientists have developed a mouse model of it. Here, fifteen different species of bacteria that were characteristic of the human gut microbiome were inserted into the guts of germ-free mice, where they grew to form a functioning microbiome. Individual bacterial cells are visible as blue, green, red, magenta, purple, and yellow rods and cocci (pictured here). Different colors indicate different gut bacteria— for example, yellow is Clostridium scindens, red is Ruminococcus torques, and blue is Bacteroides cellulosilyticus. Mouse colon tissue is visible in the lower right of the image (bright turquoise/white ovals are colon cell nuclei), and a particle of food is visible as a dim grey streak in the upper left of the image. By developing such models in mice, the scientists are beginning to understand the fine details of microbial function and behavior in healthy and diseased human microbiomes.
For more on the amazing variety of microbiomes watch “I Contain Multitudes”
The mouse colon tissue was fixed, sectioned, and hybridized with fluorescently-labeled probes targeting ribosomal RNA to identify different kinds of bacteria. The sample was imaged using fluorescence spectral imaging with a laser scanning confocal microscope. The dimensions of the image are approximately 100 micrometers high and 120 micrometers wide.
Jessica Mark Welch, PhD, The Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA and Gary Borisy, PhD Department of Microbiology, The Forsyth Institute, Cambridge, MA.