肠道原生生物 z-bo 2020-11-13 355

　　Although bacteria are often the "stars" of the gut microbiome, there are constantly new studies that portray a more complicated situation-microorganisms from different biological kingdoms actively cooperate or resist each other. In a new study published recently in the journal Cell, the researchers cited an example: a newly discovered protist that can prevent its host mice from suffering intestinal bacterial infection.

　　Miriam Merad, senior author of the paper and professor of oncology and medicine at the Icahn School of Medicine at Mount Sinai in the United States, pointed out, “This is an unexpected discovery, but it is also an important discovery. This study shows how much beyond bacteria is when studying the gut microbiome. important."

　　Researchers realized that mice grown in experimental facilities have more intestinal immune cells than mice purchased from vendors. So Aleksey Chudnovskiy, a graduate student at Icahn School of Medicine at Mount Sinai, and Arthur Mortha, a postdoctoral researcher, decided to find out why. When cleaning the intestines of the two groups of mice, they were surprised to find that there was a flagellated protozoan in the intestines of the mice from the medical school laboratory. DNA sequencing results revealed that this microbe is a new protozoan parasite, and they named it Tritrichomonas mouse.

　　Further research showed that when this protist was administered to mice that did not contain it, the number of immune cells and inflammatory cytokines in the intestine of these mice increased. Later, the researchers found that Tritrichomonas murine can activate inflammasomes in the epithelial cells of the mouse intestines, thereby activating cytokines. They also found that dendritic cells are necessary to induce inflammation.

　　In order to determine whether the colonization of mouse Tritrichomonas affects the ability of mice to resist infection, they infected the mice with Salmonella, and found that the mice with Tritrichomonas murine can resist infection very effectively. "This protective effect is amazing." Chudnovskiy said.

　　Tritrichomonas murine is an ortholog of the genus Fragile binucleus amoeba. Fragile binuclear amoeba is a parasite found in the intestines of many people, but researchers do not know whether it also has a protective effect. They plan to conduct further research. Merad explained: "People from industrialized countries are more susceptible to intestinal infections when traveling to emerging countries than local populations. The reason may be that the more common protists in emerging countries have a protective effect against pathogen infection."