OBJECTIVE: CRISPR-Cas protects bacteria from exogenous DNA invasion and is associated with bacterial biofilm formation and pathogenicity. METHODS: We analyzed the type I-F CRISPR-Cas system of Legionella pneumophila WX48, including Cas1, Cas2-Cas3, Csy1, Csy2, Csy3, and Cas6f, along with downstream CRISPR arrays. We explored the effects of the CRISPR-Cas system on the in vitro growth, biofilm-forming ability, and pathogenicity of L. pneumophila through constructing gene deletion mutants. RESULTS: The type I-F CRISPR-Cas system did not affect the in vitro growth of wild-type or mutant strains. The biofilm formation and intracellular proliferation of the mutant strains were weaker than those of the wild type owing to the regulation of type IV pili and Dot/Icm type IV secretion systems. In particular, Cas6f deletion strongly inhibited these processes. CONCLUSION The type I-F CRISPR-Cas system may reduce biofilm formation and intracellular proliferation in L. pneumophila.
Legionella pneumophila/pathogenicity* ; CRISPR-Cas Systems ; Biofilms/growth & development* ; Phenotype ; Bacterial Proteins/metabolism* ; Gene Deletion

This study was aimed at establishing a method of ultra-fast quantitative PCR for Brucella detection.We used an exogenous recombinant plasmid as the internal reference and targeted the T4SS secretion system,an important Brucella viru-lence factor,to design specific primers and probes.The sensitivity,specificity,and repeatability of this method were evaluated,and a standard curve was constructed.The coincidence rate of detection findings with this method versus quantitative PCR was determined.This method markedly decreased the detection time to only 10 minutes.The standard curve demonstrated a good linear relationship(Y=-3.410 7x+38.357,R2=0.998 5)with a low minimum detection limit of 10 copies/μL.The method exhibited good specificity and did not specifically amplify several common clinical bacteria other than Brucella.The de-tection of three concentrations of positive plasmids yielded coefficients of variation(CVs)of 0.20％to 0.91％,thus demonstra-ting the method's excellent repeatability.Furthermore,140 clinical samples were analyzed concurrently with the fluorescence PCR method,which yielded a 100％compliance rate and consistent results.Our findings indicated that the Brucella ultra-fast quantitative PCR was ultrafast;had high sensitivity,high specificity,and good specificity;and can be used for the clinical de-tection of Brucella and emergency investigation of epidemics.Therefore,this method is valuable for the early diagnosis of Bru-cella.

This study was aimed at establishing a method of ultra-fast quantitative PCR for Brucella detection.We used an exogenous recombinant plasmid as the internal reference and targeted the T4SS secretion system,an important Brucella viru-lence factor,to design specific primers and probes.The sensitivity,specificity,and repeatability of this method were evaluated,and a standard curve was constructed.The coincidence rate of detection findings with this method versus quantitative PCR was determined.This method markedly decreased the detection time to only 10 minutes.The standard curve demonstrated a good linear relationship(Y=-3.410 7x+38.357,R2=0.998 5)with a low minimum detection limit of 10 copies/μL.The method exhibited good specificity and did not specifically amplify several common clinical bacteria other than Brucella.The de-tection of three concentrations of positive plasmids yielded coefficients of variation(CVs)of 0.20％to 0.91％,thus demonstra-ting the method's excellent repeatability.Furthermore,140 clinical samples were analyzed concurrently with the fluorescence PCR method,which yielded a 100％compliance rate and consistent results.Our findings indicated that the Brucella ultra-fast quantitative PCR was ultrafast;had high sensitivity,high specificity,and good specificity;and can be used for the clinical de-tection of Brucella and emergency investigation of epidemics.Therefore,this method is valuable for the early diagnosis of Bru-cella.

In recent years,natural antimicrobial peptides have become an important direction in the development of novel antibiotics.Cecropin has the characteristics of wide antibacterial spectrum,good tolerance and low adverse drug reactions.As the first antimicrobial peptide discovered in the family of Cecropin,Cecropin A has many important biological activities.In this paper,the research on the antibacterial,antifungal,antiparasitic and antitumor activities of Cecropin A and its derivatives in recent years was reviewed,and its application prospect was prospected,in order to provide reference for further research and development of cecropin.

OBJECTIVE: To investigate the role of multiple serological methods in the identification of complex antibodies. METHODS: The blood group antigens were detected by saline and microcolumn agglutination methods. The saline method was used to screen and identify IgM-type antibodies in the patient's serum, while the polybrene, anti-globulin, microcolumn agglutination, enzymic and absorption-elution methods were used to screen and identify IgG-type antibodies. RESULTS: The patient was B/CCDee/Jk(a-b+)/Fy(a-b+) blood type. The serum reacted with panel cells, and the reaction presented anti-E pattern in the saline medium. It was fully positive in the microcolumn agglutination card, except 2 negative ones after using papain to treat the panel cells. Referring to the pattern table, it was concluded that there existed anti-c, anti-E, and anti-Jk^a antibodies, and one antibody corresponding to an antigen that was easily destroyed by papain. The red blood cells with specific phenotype were selected for absorption-elution to identify IgG-type anti-c, anti-E, anti-Jk^a and anti-Fy^a antibodies. CONCLUSION It is confirmed that IgM-type anti-E, and IgG-type anti-c, anti-E, anti-Jk^a and anti-Fy^a antibodies exist in the patient's serum by multiple serological methods.
Humans ; Papain ; Blood Group Antigens ; Erythrocytes ; Immunoglobulin G ; Immunoglobulin M

In this paper, the extraction rate of crude polysaccharides and the yield of polysaccharides from Hippocampus served as test indicators. The comprehensive evaluation indicators were assigned by the R language combined with the entropy weight method. The Box-Behnken design-response surface methodology(BBD-RSM) and the deep neural network(DNN) were employed to screen the optimal parameters for the polysaccharide extraction from Hippocampus. These two modeling methods were compared and verified experimentally for the process optimization. This study provides a reference for the industrialization of effective component extraction from Chinese medicinals and achieves the effective combination of modern technology and traditional Chinese medicine.
Dietary Carbohydrates ; Hippocampus ; Neural Networks, Computer ; Polysaccharides ; Temperature

Objective:To clarify the effect of Fangfeng Tongshengtang on early-stage serum endotoxin (ET) and programmed death-1/programmed ligand-1(PD-1/PD-L1) in patients with hepatitis B virus-related acute-on-chronic liver failure（HBV-ACLF）(early-stage), and exploring the mechanism of Fangfeng Tongshengtang in the treatment of early stage HBV-ACLF. Method:The 69 patients with early stage HBV-ACLF were enrolled in the study and all of them received antiviral drugs, liver protection and jaundice relieving drugs as well as supporting therapy. According to the random number table, 35 patients were randomly assigned to observation group (to take Fangfeng Tongshengtang, and 34 patients were assigned to control group to take placebo. The observation period was 3 weeks in both groups. Before treatment and 1, 2, and 3 weeks after treatment, theserum ET, expression of PD-1/PD-L1 in serum CD4⁺ and CD8⁺ T cells, liver function [alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (Alb), total bilirubin (TBIL), and direct bilirubin (DBIL)], coagulation function [prothrombin time (PT), and prothrombin activity (PTA)] were detected to verify the effect of Fangfeng Tongshengtang on HBV-ACLF (early-stage). Result:After 3 weeks of treatment, ET, expression of serum CD4⁺PD-1⁺, CD4⁺PD-L1⁺, CD8⁺PD-1⁺, CD8⁺PD-L1⁺, ALT, AST, TBIL, DBIL, and PT decreased significantly (P<0.01), while Alb and PTA increased significantly（P<0.01）in both groups. As compared with the control group, the ET in observation group was lower at 1^st, 2^nd and 3^rd week after treatment (P<0.01), the CD4⁺PD-1⁺, CD4⁺PD-L1⁺, CD8⁺PD-1⁺ and CD8⁺PD-L1⁺ in observation group were lower at 2^nd week and 3^rd week（P<0.05, P<0.01）， the ALT, AST, TBIL and DBIL in observation group were lower at 1^st, 2^nd and 3^rd week（P<0.05, P<0.01）， the PT in observation group was lower at 2^nd and 3^rd week（P<0.05）， and the PTA in observation group was higher at the 2^nd and 3^rd week（P<0.01）. Conclusion:Fangfeng Tongshengtang can achieve the therapeutic effect for HBV-ACLF (early-stage) probably by reducing the serum ET and the expression of PD-1 / PD-L1 in serum CD4 ⁺, CD8 ⁺ T cells.