Beschreibung:
<jats:sec><jats:title>Purpose</jats:title><jats:p>This study aimed to investigate the presence of rhythmic fluctuations in the composition, abundance, and functions of commensal core bacteria on the ocular surface of C57BL/6J mice.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Male C57BL/6J mice, aged 12 weeks, were subjected to a 12-hour light/12-hour dark cycle. Ocular surface tissue samples were collected at four time points (ZT) over a 24-hour period at six-hour intervals. The core ocular surface microbiota’s oscillation cycles and frequencies were assessed using 16S rRNA gene sequencing targeting the V3-V4 region, along with the JTK_CYCLE algorithm. Functional predictions of these bacteria were conducted using PICRUSt2.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Deep sequencing of the ocular surface microbiota highlighted the high abundance of commensal bacteria, with <jats:italic>Proteobacteria</jats:italic>, <jats:italic>Actinobacteriota</jats:italic>, and <jats:italic>Firmicutes</jats:italic> collectively constituting over 90% of the total sample abundance. Among the 22 core bacterial genera, 11 exhibited robust 12-hour rhythms, including <jats:italic>Halomonas</jats:italic>, <jats:italic>Pelagibacterium</jats:italic>, <jats:italic>Pseudomonas</jats:italic>, <jats:italic>Nesterenkonia</jats:italic>, <jats:italic>norank_f_Hyphomonadaceae</jats:italic>, <jats:italic>Stenotrophomonas</jats:italic>, <jats:italic>Anoxybacillus</jats:italic>, <jats:italic>Acinetobacter</jats:italic>, <jats:italic>Zoogloea</jats:italic>, <jats:italic>Brevibacillus</jats:italic>, and <jats:italic>Ralstonia</jats:italic>. Further taxonomic analysis indicated significant intra-cluster similarities and inter-cluster differences at the order, family, and genus levels during ZT0/12 and ZT6/18. Community interaction networks and functional prediction analyses revealed synchronized 12-hour rhythmic oscillations in neural, immune, metabolic, and other pathways associated with symbiotic bacteria.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>This study demonstrates the presence of ultradian rhythmic oscillations in commensal bacteria on the ocular surface of normal C57BL/6J mice, with a 12-hour cycle. These findings suggest a crucial role for ultradian rhythms in maintaining ocular surface homeostasis in the host.</jats:p></jats:sec>