[Biological characteristics of a human specifically targeted antimicrobial peptide C16LL-37 against Streptococcus mutans].

OBJECTIVE: This study aimed to evaluate the biological characteristics of a human specifically targeted antimi- crobial peptide C16LL-37 against Streptococcus mutans (S. mutans). METHODS: In this study, an antimicrobial peptide LL-37, a peptide derived from CSP(C16) (S. mutans competence stimulating peptide), and recombinant peptide C16LL-37 were synthesized by Fmoc-chemistry-based strategy. The selectivity and antibacterial activity of C16LL-37 were identified by the colony counting method on microbial culture plates. After treatment of C16LL-37 at 32 µmol · L⁻¹, the morphological changes in S. mutans were observed by using scanning electron microscopy (SEM). In addition, enzyme-linked immunosorbent assay was used to evaluate the hemolytic activity and antibacterial activity of C16LL-37 under different conditions. RESULTS: 1) The minimum inhibitory concentration of C16LL-37 was 16 µmol · L⁻¹, and the minimum bactericidal concentration was 64 µmol ·L⁻¹. 2) The survival rate of S. mutans was 3.46% after C16LL-37 treatment at 64 µmo-L⁻¹ for 30 min, whereas it was 0% at 64 µmol · L⁻¹ for 60 min. The survival rates of four other kinds of bacteria were more than 60% at any time (P < 0.05). 3) The morphological change in S. mutans was observed after C16LL-37 treatment at 32 µmol · L⁻¹ by using SEM. S. mutans presented an irregular shape, rough surface, and evident splitting. 4) The hemolysis rate of C16LL-37 (≤ 64 µmol · L⁻¹) was less than 0.33%. 5) This study showed no significant in- fluence on the antibacterial activity of C16LL-37 under different conditions, such as temperature, pH, salinity, and trypsin at low concentration (P > 0.05). CONCLUSION: C16LL-37 exhibited obvious specificity for S. mutans, strong antibacterial activity, low toxicity, and high stability. Thus, C16LL-37 has good potential in caries research and clinical application.

[Construction of human mucosa oral epithelial cell lines overexpressing telomerase reverse transcriptase gene mediated by lentivirus].

OBJECTIVE: To construct a cell line of oral mucosa epithelial cells that stably express human telomerase reverse transcriptase (hTERT) by lentiviral vectors, approaches for the establishment of stable and efficient immortalized oral mucosa epithelial cell lines were explored. METHODS: Whole RNA was extracted from 293T cells. The hTERT gene was amplified by polymerase chain reaction (PCR) and cloned into the lentiviral vector as pLVX-puro-hTERT. The lentivirus particles were successfully packaged and used to infect primary oral epithelial cells. The positive cell clones were selected by puromycin. Finally, the expression of hTERT was examined by real-time fluorescent quantitative PCR (qRT-PCR) and Western blot analysis. RESULTS: The sequencing results confirmed the construction of the recombinant lentivirus pLVX-puro-hTERT. The morphology of infected cells was similar to that of normal oral mucosal epithelial cells, with a cobble stone-like appearance. The qRT-PCR and Western blot results showed that hTERT was overexpressed in infected cells compared with the normal group (P<0.05). CONCLUSIONS: The oral epithelial cell line with stable expression of hTERT was successfully established by the lentivirus, which provides an experimental basis for the establishment of a highly efficient and stable oral epithelial immortalized cell line.

Biological characteristics of a human specifically targeted antimicrobial peptide C16LL-37 against Streptococcus mutans / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to evaluate the biological characteristics of a human specifically targeted antimi- crobial peptide C16LL-37 against Streptococcus mutans (S. mutans).</p><p><b>METHODS</b>In this study, an antimicrobial peptide LL-37, a peptide derived from CSP(C16) (S. mutans competence stimulating peptide), and recombinant peptide C16LL-37 were synthesized by Fmoc-chemistry-based strategy. The selectivity and antibacterial activity of C16LL-37 were identified by the colony counting method on microbial culture plates. After treatment of C16LL-37 at 32 µmol · L⁻¹, the morphological changes in S. mutans were observed by using scanning electron microscopy (SEM). In addition, enzyme-linked immunosorbent assay was used to evaluate the hemolytic activity and antibacterial activity of C16LL-37 under different conditions.</p><p><b>RESULTS</b>1) The minimum inhibitory concentration of C16LL-37 was 16 µmol · L⁻¹, and the minimum bactericidal concentration was 64 μmol ·L⁻¹. 2) The survival rate of S. mutans was 3.46% after C16LL-37 treatment at 64 µmo-L⁻¹ for 30 min, whereas it was 0% at 64 µmol · L⁻¹ for 60 min. The survival rates of four other kinds of bacteria were more than 60% at any time (P < 0.05). 3) The morphological change in S. mutans was observed after C16LL-37 treatment at 32 µmol · L⁻¹ by using SEM. S. mutans presented an irregular shape, rough surface, and evident splitting. 4) The hemolysis rate of C16LL-37 (≤ 64 µmol · L⁻¹) was less than 0.33%. 5) This study showed no significant in- fluence on the antibacterial activity of C16LL-37 under different conditions, such as temperature, pH, salinity, and trypsin at low concentration (P > 0.05).</p><p><b>CONCLUSION</b>C16LL-37 exhibited obvious specificity for S. mutans, strong antibacterial activity, low toxicity, and high stability. Thus, C16LL-37 has good potential in caries research and clinical application.</p>

Construction of human mucosa oral epithelial cell lines overexpressing telomerase reverse transcriptase gene mediated by lentivirus / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To construct a cell line of oral mucosa epithelial cells that stably express human telomerase reverse transcriptase (hTERT) by lentiviral vectors, approaches for the establishment of stable and efficient immortalized oral mucosa epithelial cell lines were explored.</p><p><b>METHODS</b>Whole RNA was extracted from 293T cells. The hTERT gene was amplified by polymerase chain reaction (PCR) and cloned into the lentiviral vector as pLVX-puro-hTERT. The lentivirus particles were successfully packaged and used to infect primary oral epithelial cells. The positive cell clones were selected by puromycin. Finally, the expression of hTERT was examined by real-time fluorescent quantitative PCR (qRT-PCR) and Western blot analysis.</p><p><b>RESULTS</b>The sequencing results confirmed the construction of the recombinant lentivirus pLVX-puro-hTERT. The morphology of infected cells was similar to that of normal oral mucosal epithelial cells, with a cobble stone-like appearance. The qRT-PCR and Western blot results showed that hTERT was overexpressed in infected cells compared with the normal group (P<0.05).</p><p><b>CONCLUSIONS</b>The oral epithelial cell line with stable expression of hTERT was successfully established by the lentivirus, which provides an experimental basis for the establishment of a highly efficient and stable oral epithelial immortalized cell line.</p>

Study on preparation of ampelopsin liposomes / 中国中药杂志

<p><b>OBJECTIVE</b>To study the formulation and preparation of ampelopsin liposomes and evaluate their quality.</p><p><b>METHOD</b>The liposomes were prepared by a film-ultrasonic dispersion technique. Served as quota with the entrapment ratio and appearance and diameter of the liposomes, the optimal formulation and preparation were selected by means of an uniform design test. The appearance of liposomes was observed by micrography. The diameter and electric charge of surface were determined by granularity mensuration instrument. The entrapment ratio and the leakage rate of ampelopsin liposome were determined by means of dialyze. The content of ampelopsin was determined by UV.</p><p><b>RESULT</b>The result of electron micrography and the size distribution showed that the liposomes were similar to spherical small unilamellar vesicles. The mean diameter was (258.2 +/- 51.2) nm and the electric charge of surface is 19.0 mV. The entrapment ratio of ampelopsin liposomes was 62. 3% and the lecithoid oxidative rate was 0.83% (n = 3).</p><p><b>CONCLUSION</b>The selected formulation and preparation of ampelopsin liposomes is efficient and practicable.</p>

Ampelopsin, a small molecule inhibitor of HIV-1 infection targeting HIV entry / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the anti-HIV effects of ampelopsin and its interaction with HIV-1 coreceptor CXCR4.</p><p><b>METHODS</b>Through anti-virus experiments in vitro, the inhibitory effect of ampelopsin on HIV-1 infection was verified. Chemotaxis assay was performed to show the ability to induce PBMCs migration by ampelopsin, RANTES and SDF-1alpha. Fluorescence labelling monoclonal antibody was utilized to observe the interaction of ampelopsin and CXCR4. Mice immunosuppressant model was also established to detail the role ampelopsin played in regulating cellular immunological functions.</p><p><b>RESULTS</b>Ampelopsin could protect sensitive cells against HIV-1 infection and dramatically reduce HIV-1 antigen P24 expression. HIV-1SF33 attaching to MT-4 cells was interfered by ampelopsin, and the EC50 was 0.175 mg/mL for cellular protection and 0.024 mg/mL for P24 inhibition. At co-cultivating phase, EC50 was 0.229 mg/mL and 0.197 mg/mL respectively. Furthermore, the EC50 was 0.179 mg/mL and 0.348 mg/mL in acute infection. Human PBMCs migration was induced after being challenged with ampelopsin or chemokines, and synergistic action was observed during co-treatment. Ampelopsin alone resulted in maximal chemotaxis at 1 mg/mL. HIV-1 co-receptor CXCR4 on the surface of PBMCs was decreased by internalization, which indicated the effect of ampelopsin on CXCR4. About 70% CXCR4 was reduced by ampelopsin at 1 mg/mL. Ampelopsin also augmented cellular immunological functions in immunosuppressive mice.</p><p><b>CONCLUSION</b>Ampelopsin displays a strong inhibitive role during HIV-1 absorption, incubation and acute infection. These results are coincident with its immune enhancement.</p>