{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,2]],"date-time":"2026-11-02T04:03:11Z","timestamp":1793592191448,"version":"4.5.0"},"reference-count":101,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,1,16]],"date-time":"2023-01-16T00:00:00Z","timestamp":1673827200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>The gut microbiota features a unique diurnal rhythmicity which contributes to modulation of host physiology and homeostasis. The composition and activity of the microbiota and its secreted molecules influence the intestinal milieu and neighboring organs, such as the liver. Multiple immune-related molecules have been linked to the diurnal microbiota-host interaction, including Reg3\u03b3, IgA, and MHCII, which are secreted or expressed on the gut surface and directly interact with intestinal bacteria. These molecules are also strongly influenced by dietary patterns, such as high-fat diet and time-restricted feeding, which are already known to modulate microbial rhythms and peripheral clocks. Herein, we use Reg3\u03b3, IgA, and MHCII as test cases to highlight the divergent effects mediated by the diurnal activity of the gut microbiota and their downstream host effects. We further highlight current challenges and conflicts, remaining questions, and perspectives toward a holistic understanding of the microbiome\u2019s impacts on circadian human behavior.<\/jats:p>","DOI":"10.3390\/biology12010142","type":"journal-article","created":{"date-parts":[[2023,1,17]],"date-time":"2023-01-17T01:41:20Z","timestamp":1673919680000},"page":"142","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["Small Intestinal Microbiota Oscillations, Host Effects and Regulation\u2014A Zoom into Three Key Effector Molecules"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3458-5604","authenticated-orcid":false,"given":"Karina","family":"Ratiner","sequence":"first","affiliation":[{"name":"Systems Immunology Department, Weisman Institute of Science, Rehovot 7610001, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tahel","family":"Fachler-Sharp","sequence":"additional","affiliation":[{"name":"Systems Immunology Department, Weisman Institute of Science, Rehovot 7610001, Israel"},{"name":"Department of Dermatology, Hadassah-Hebrew University Medical Center, Jerusalem 9987500, Israel"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5775-2110","authenticated-orcid":false,"given":"Eran","family":"Elinav","sequence":"additional","affiliation":[{"name":"Systems Immunology Department, Weisman Institute of Science, Rehovot 7610001, Israel"},{"name":"Microbiota & Cancer Division, Deutsches Krebsforschungszentrum (DKFZ), 69120 Heidelberg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"16219","DOI":"10.1073\/pnas.1408886111","article-title":"A Circadian Gene Expression Atlas in Mammals: Implications for Biology and Medicine","volume":"111","author":"Zhang","year":"2014","journal-title":"Proc. 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