Katharina Ribbeck’s Laboratory collects mucus – the often sticky substance found in places such as the mouth, intestines, reproductive tract and intestines. While the slimy goop may not be gendered from the start, a cleansing process may brighten up. “When you remove particles and microbes, it’s a beautiful, pretty clear gel – like egg whites,” says Ribbeck, a professor of biotechnology at the Massachusetts Institute of Technology. “It’s really nice.”
Ribbeck worries about saliva because she is trying to deconstruct how glycans, small sugar molecules hidden inside mucus, work to keep a particular organism healthy. Researchers already know that mucus is important for maintaining human health and supporting the microbiome. The work of the glycans is critical, according to Ribbeck and others. They specialize in dealing with microorganisms that can be beneficial – help with food digestion, regulate immunity and protect against bacteria – but which can be harmful if they outcompete each other or become virulent, which can potentially lead to infection. Like microscopic conductors, glycans ensure that each section of the microbial orchestra plays in harmony.
In a examination published this month in Chemical biology of natureshowed Ribbeck and her collaborators how glycans hold a fungus called Candida albicans (C. albicans) from becoming problematic. The boundary between friend and foe is the fog drawn in case of C. albicans. The fungus is polymorphic, which means that it can take various forms: a rounded, yeast-like structure (generally considered normal) can turn into a filamented, thread-like shape associated with virulence. While the fungus can contribute to immunity, it can also lead to yeast infections or, even more seriously, a systemic infection in the bloodstream.
Sing Sing Way, a medical scientist at Cincinnati Children’s Hospital Medical Center who was not involved in this study, has been researching ways to transform Candida can be beneficial to human health. “Complex microbes like Candida has evolved with not just humans but other mammalian hosts for a long, long time, Way says. “They have developed strategies where it is good for both.” He believes that if we understand why and how the fungi change shape, we can take advantage of this relationship to keep them in good behavior.
Ribbeck’s group had done Former job to determine how mucus prevents other microbes from becoming dangerous. In this new set of experiments, the researchers wanted to know exactly how it works in the case of C. albicans.
But first, they needed a lot of dirt. “It’s surprisingly difficult to collect larger amounts of mucus,” Ribbeck says. “It’s a really valuable material.” The team collected three types of mucus using different methods: aspirating human saliva (similar to the way a dentist uses a suction hose to suck saliva from under a patient’s tongue), as well as scraping the inside of pig intestines and stomachs. They then incubated the purified mucus with C. albicans inside a well plate – a clear rectangular dish, characterized by 96 beehive-like holes containing small amounts of fungi.
They found that all three types of mucus prevented the fungi from adhering to the plate compared to a negative control. C. albicans also seemed rounder when the mucus was present, in contrast to the elongated version associated with filamentation. This, the researchers believed, suggested that the mucus could prevent the fungus from adhering to bodily surfaces or forming biofilms, which are stringy, intertwined layers of the fungi associated with infections.