Stem cells (SCs) receive inductive cues from the surrounding microenvironment and cells. Limited molecular evidence has connected tissue-specific mesenchymal stem cells (MSCs) with mesenchymal transit amplifying cells (MTACs). Using mouse incisor as the model, we discover a population of MSCs neibouring to the MTACs and epithelial SCs. With Notch signaling as the key regulator, we disclose molecular proof and lineage tracing evidence showing the distinct MSCs contribute to incisor MTACs and the other mesenchymal cell lineages. MTACs can feedback and regulate the homeostasis and activation of CL-MSCs through Delta-like 1 homolog (Dlk1), which balances MSCs-MTACs number and the lineage differentiation. Dlk1 ’s function on SCs priming and self-renewal depends on its biological forms and its gene expression is under dynamic epigenetic control. Our findings can be validated in clinical samples and applied to accelerate tooth wound healing, providing an intriguing insight of how to direct SCs towards tissue regeneration.

Salinarimonas rosea gen. nov., sp. nov., a new member of the a-2 subgroup of the Proteobacteria

Fodinibius salinus gen. nov., sp. nov., a moderately halophilic bacterium isolated from a salt mine

Two rod-shaped, non-motile bacteria were isolated from two separate salt mines in Yunnan, south-western China. These strains, designated YIM D15T and YIM J21T, were Gram-negative and moderately halophilic. The two strains required 6–10 % NaCl (w/v; optimal) for growth. The DNA G+C contents of strains YIM D15T and YIM J21T were 49.0 mol% and 48.4 mol%, respectively. The predominant isoprenoid quinone was MK-7. The polar lipid profiles of strains YIM D15T and YIM J21T were composed predominantly of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, three unknown polar lipids and one glycolipid. Minor amounts of other lipids were also detectable. The predominant cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C17 : 1ω9c/10 methyl-C16 : 0 and C16 : 1ω7c/C16 : 1ω6c. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that the two isolates formed a distinct clade with the genus Fodinibius (in the phylum Bacteroidetes ) and were related to the species Fodinibius salinus , with sequence similarities of 91.9–92.4 %. Analyses of 16S rRNA gene sequences revealed that strains YIM D15T and YIM J21T were related to each other (97.3 % sequence similarity). The DNA–DNA hybridization relatedness between the two isolates was 34 %. On the basis of the phylogenetic analysis, DNA–DNA hybridization relatedness, phenotypic and chemotaxonomic characteristics, strains YIM D15T and YIM J21T should be classified as members of a novel genus and as two novel species, for which the names Aliifodinibius roseus gen. nov., sp. nov. (type strain YIM D15T = ACCC 10715T = KCTC 23442T) and Aliifodinibius sediminis sp. nov. (type strain YIM J21T = ACCC 10714T = DSM 21194T) are proposed.

No abstract