Fusobacterium nucleatum is an opportunistic pathogenic bacterium that can be enriched in colorectal cancer tissues, affecting multiple stages of colorectal cancer development. The two-component system plays an important role in the regulation and expression of genes related to pathogenic resistance and pathogenicity. In this paper, we focused on the CarRS two-component system of F. nucleatum, and the histidine kinase protein CarS was recombinantly expressed and characterized. Several online software such as SMART, CCTOP and AlphaFold2 were used to predict the secondary and tertiary structure of the CarS protein. The results showed that CarS is a membrane protein with two transmembrane helices and contains 9 α-helices and 12 β-folds. CarS protein is composed of two domains, one is the N-terminal transmembrane domain (amino acids 1-170), the other is the C-terminal intracellular domain. The latter is composed of a signal receiving domain (histidine kinases, adenylyl cyclases, methyl-accepting proteins, prokaryotic signaling proteins, HAMP), a phosphate receptor domain (histidine kinase domain, HisKA), and a histidine kinase catalytic domain (histidine kinase-like ATPase catalytic domain, HATPase_c). Since the full-length CarS protein could not be expressed in host cells, a fusion expression vector pET-28a(+)-MBP-TEV-CarS_cyto was constructed based on the characteristics of secondary and tertiary structures, and overexpressed in Escherichia coli BL21-Codonplus(DE3)RIL. CarS_cyto-MBP protein was purified by affinity chromatography, ion-exchange chromatography, and gel filtration chromatography with a final concentration of 20 mg/ml. CarS_cyto-MBP protein showed both protein kinase and phosphotransferase activities, and the MBP tag had no effect on the function of CarS_cyto protein. The above results provide a basis for in-depth analysis of the biological function of the CarRS two-component system in F. nucleatum.
Humans ; Histidine Kinase/metabolism* ; Fusobacterium nucleatum/metabolism* ; Automobiles ; Protein Kinases/genetics* ; Escherichia coli/metabolism* ; Colorectal Neoplasms

Fusobacterium nucleatum (Fn) is an oral anaerobic bacterium that has recently been found to colonize on the surface of colorectal cancer cells in humans, and its degree of enrichment is highly negatively correlated with the prognosis of tumor treatment. Numerous studies have shown that Fn is involved in the occurrence and development of colorectal cancer (CRC), and Fn interacts with multiple components in the tumor microenvironment to increase tumor resistance. In recent years, researchers have begun using nanomedicine to inhibit Fn's proliferation at the tumor site or directly target Fn to treat CRC. This review summarizes the mechanism of Fn in promoting CRC and the latest research progress on Fn-related CRC therapy using different nanomaterials. Finally, the applications perspective of nanomaterials in Fn-promoted CRC therapy was prospected.
Humans ; Colorectal Neoplasms/pathology* ; Fusobacterium nucleatum/genetics* ; Base Composition ; RNA, Ribosomal, 16S ; Phylogeny ; Sequence Analysis, DNA ; Tumor Microenvironment

OBJECTIVETo detect the presence and distribution of luxS gene in quorum sensing signal system in the periodontal pathogens.

METHODSThe total DNA of Porphyromonas gingivalis (Pg), Fusobacterium nucleatum (Fn), Actinobacillus acitinomycetimcomtans (Aa) were extracted. The presence of luxS was detected by polymerase chain reaction (PCR). The products of PCR were detected by electrophoresis, sequenced and identified by a Blast search of the GenBank database.

RESULTSElectrophoresis, sequencing and Blast searching indicated that the PCR products of Pg were highly consistent with the luxS gene in GenBank. The sequencing result of Fn was also identified with the target gene. The PCR product of Aa was the same as reference through electrophoresis.

CONCLUSIONSPg, Fn, Aa contain luxS gene. Further studies may be required to investigate the functions of luxS in the periodontal pathogens.

Aggregatibacter actinomycetemcomitans ; genetics ; metabolism ; Bacterial Proteins ; genetics ; isolation & purification ; metabolism ; Carbon-Sulfur Lyases ; genetics ; isolation & purification ; metabolism ; Fusobacterium nucleatum ; genetics ; metabolism ; Gene Expression Regulation, Bacterial ; Porphyromonas gingivalis ; genetics ; metabolism ; Quorum Sensing ; genetics ; Signal Transduction