Dopamine alters phage morphology to exert an anti-infection effect.

Antiviral drug development is important for human health, and the emergence of novel COVID-19 variants has seriously affected human lives and safety. A bacteriophage-a bacterial virus with a small and simple structure-is an ideal experimental candidate for studying the interactions between viruses and their hosts. In this study, the effects and mechanisms of catecholamines on phages were explored, and dopamine (DA) was found to have general and efficient anti-infection effects. A clear dose-dependent effect was observed when different phages were treated with DA, with higher DA concentrations exhibiting stronger anti-phage activity. The half maximal inhibitory concentration values of DA for vB-EcoS-IME167, T4 Phage, and VMY22 were determined as 0.26, 0.12, and 0.73 mg mL-1, respectively. The anti-phage effect of DA increased with treatment duration. In addition, the anti-infection activities of DA against vB-EcoS-IME167, T4 Phage, and VMY22 were increased by 105, 104, and 104 folds compared to that of the control. This ability of DA was observed only in phages and not in the host bacteria. Morphological changes of phages were observed under transmission electron microscopy following their treatment with DA, and considerable changes in adsorption were confirmed via quantitative reverse transcription polymerase chain reaction. These results suggest that the anti-phage effect of DA is primarily due to the destruction of the external structure of the phage. This study, to the best of our knowledge, is the first to report the universal anti-phage infection effect of dopamine, which provides novel information regarding DA and forms a basis for further research and development of antiviral drugs. Moreover, it provides a new perspective for the research about the defense and counter-defense of bacteria and bacteriophages.

[The value of serum tumor marker in the diagnosis of lung cancer].

OBJECTIVE: To evaluate five serum tumor markers used alone or in combination for the diagnosis of lung cancer. METHODS: The level of five serum tumor markers: NSE, pro-GRP, CYFRA21-1, p53 antibody and CEA was detected by ELISA in 50 healthy adults, 170 lung cancer patients and 60 patients with respiratory infection. RESULTS: The level of the five serum tumor markers in lung cancer patients was significantly higher than that of healthy adults and patients with respiratory infection (P < 0.01). The level of NSE and pro-GRP in patients with small-cell lung cancer was significantly higher than those of the other subtypes of lung cancer (P < 0.01); The level of CYFRA21-1 in patients with squamous-cell carcinoma was significantly higher than that of other subtypes (P < 0.01). The specificity of p53 antibody was 100% in diagnosing lung cancer and the sensitivity of NSE, pro-GRP was much higher for small-cell lung cancer than for other subtypes (P < 0.01); The same was observed in CYFRA21-1 for the diagnosis of squamous-cell carcinoma (P < 0.01). The sensitivity of the tumor markers in diagnosing lung cancer was significantly enhanced if used in combination (P < 0.01). CONCLUSION: These five tumor markers are valuable auxiliary parameters in diagnosing lung cancer. The combination of NSE and pro-GRP is more appropriate than other combinations in diagnosing small-cell lung cancer; the combination of CYFRA21-1, CEA and p53 antibody is the most valuable combination for diagnosing non-small-cell lung cancer. p53 antibody has the highest specificity for diagnosing lung cancer; CYFRA21-1 is the most valuable parameter for diagnosing squamous carcinoma.