Single-cell RNA-seq reveals distinct metabolic "microniches" and close host-symbiont interactions in deep-sea chemosynthetic tubeworm.

Vestimentiferan tubeworms that thrive in deep-sea chemosynthetic ecosystems rely on a single species of sulfide-oxidizing gammaproteobacterial endosymbionts housed in a specialized symbiotic organ called trophosome as their primary carbon source. While this simple symbiosis is remarkably productive, the host-symbiont molecular interactions remain unelucidated. Here, we applied an approach for deep-sea in situ single-cell fixation in a cold-seep tubeworm, .

Differential roles of the fish chitinous membrane in gut barrier immunity and digestive compartments.

The chitin-based peritrophic matrix (PM) is a structure critical for both gut immunity and digestion in invertebrates. PM was traditionally considered lost in all vertebrates, but a PM-like chitinous membrane (CM) has recently been discovered in fishes, which may increase the knowledge on vertebrate gut physiology and structural evolution. Here, we show that in zebrafish, the CM affects ingestion behavior, microbial homeostasis, epithelial renewal, digestion, growth, and longevity.