Benzannulation with Et3N as 1,3-Diene Variants.

With triethylamine as a 1,3-diene variant, a simple and practical process for the synthesis of phthalimides has been developed from readily available maleimide. The transformation can be performed in the absence of a metal catalyst with high levels of functional group tolerance. Various phthalimide compounds were constructed in moderate to good yields under mild conditions. Mechanism research indicates that oxygen and acid also play crucial roles in this reaction.

The role of ZBTB16 in odontogenic differentiation of dental pulp stem cells.

OBJECTIVE: Odontogenic differentiation of dental pulp stem cells (DPSCs) is highly controlled by the activation of several transcription factors. The zinc finger and BTB domain-containing 16 (ZBTB16) gene encodes a BTB/POZ domain and zinc finger containing transcription factors and is involved in several biological processes, but little is known about its role in odontogenic differentiation. The main goal of the current study was to determine the role of ZBTB16 in odontogenic differentiation of DPSCs. DESIGN: ZBTB16, runt-related transcription factor 2 (RUNX2), and osterix (OSX) were silenced via small-hairpin RNA (shRNA) lentivirus. The odontoblastic differentiation of DPSCs was detected by alkaline phosphatase (ALP) staining, activity measurement, and alizarin red S staining in vitro. The gene and protein expression levels were assessed by RT-qPCR and western blotting. Further, an ectopic implantation experiment was performed to explore the role of ZBTB16 in mineralization regulation in vivo followed by histological examination. RESULTS: The silencing of ZBTB16 attenuated ALP activity and mineralized nodules formation by DPSCs. In addition, knockdown of ZBTB16 impaired the expression of markers involved in odontogenic differentiation, including dentin sialophosphoprotein, dentin matrix acidic phosphoprotein 1, and collagen 1 in vitro and vivo. Silencing the OSX gene suppressed ZBTB16 expression and, in turn, OSX expression decreased after ZBTB16 knockdown. However, shRUNX2 did not suppress ZBTB16 expression and shZBTB16 did not affect RUNX2 expression. CONCLUSIONS: ZBTB16 may play an important role in modulating the odontoblastic differentiation of DPSCs and act as a regulator of OSX in a possible feed-back cycle independent of RUNX2.

Recombinant bacteriophage T4 Rnl1 impacts Streptococcus mutans biofilm formation.

Bacteriophage T4 RNA ligase 1 (T4 Rnl1) can be stably expressed in many bacteria and has been reported to affect the bioactivity of the host bacteria. Recently, we constructed bacteriophage T4 Rnl1 expressing system in Streptococcus mutans, a crucial biofilm-forming and dental caries-causing oral pathogen. Here, we characterized the function of recombinant bacteriophage T4 Rnl1 in biofilm formation of S. mutans. The T4 Rnl1 mutant exhibited similar growth phenotype but resulted in a significant reduction of biofilm biomass compared to wild type strain and empty plasmid carrying strain. The abnormal biofilm of the T4 Rnl1 mutant harbored loose bacterial clusters with defective production and distribution of exopolysaccharides. Moreover, the expression of several biofilm formation-associated genes was dysregulated at mRNA level in the T4 Rnl1 mutant. These results reveal that the bacteriophage T4 Rnl1 exert antibiofilm activities against the cariogenic bacterium S. mutans, which impacts the spatial organization of the exopolysaccharides and further impairs the three-dimensional biofilm architecture. These findings implicate that manipulation of bacteriophage T4 Rnl1, a biological tool used for RNA ligation, will provide a promising approach to cariogenic biofilm control.