A universal dual-mode hydrogel array based on phage-DNA probe for simultaneous rapid screening and precisely quantitative detection of Escherichia coli O157:H7 in foods by the fluorescent/microfluidic chip electrophoresis methods.

Rapid and specific detection of virulent bacterial strains is a great challenge for food safety regarding large amounts of contaminated samples. Herein, a dual-mode hydrogel array biosensor was constructed to simultaneously rapidly screen and precisely quantitatively detect virulent Escherichia coli O157:H7 (E. coli O157:H7) based on a novel DNA-modified phage probe. First, E. coli O157:H7 was incubated with alginate to form the E. coli O157:H7/hydrogel premix complex. Subsequently, hydrogel formation by cross-linking upon the addition of calcium ions and phages for E. coli O157:H7 modified with a DNA primer (phage-DNA) was added to the alginate hydrogel. The DNA on the complex could trigger rolling circle amplification (RCA) to form a phage probe containing a long-chain DNA skeleton (phage@RCA-DNA). The RCA-DNA was then hybridized with the complementary DNA (cDNA) to form double-stranded DNA fragments (phage@RCA-dsDNA), which could be stained by the SYBR Green dye to emit visual green fluorescence (FL) and determined by a smartphone for rapid screening. Meanwhile, the unreacted cDNA in the supernatant could be quantitatively detected by microfluidic chip electrophoresis (MCE). The signal decrement was also proportional to the bacterial concentration. The detection limit values of E. coli O157:H7 were 50 CFU mL-1 by the FL signal and 6 CFU mL-1 by the MCE signal. The two results could be mutually corrected to decrease the false-positive results. This assay was also employed to detect virulent Salmonella Typhimurium (S. Typhimurium) using the corresponding S. Typhimurium phage@RCA-DNA probe. All these results demonstrated that the universal bioassay was suitable for simultaneous rapid screening and precisely quantitative detection of virulent bacterial strains.

Femtomolar endogenous adenosine triphosphate-responded photoelectrochemical biosensor based on Au@Cu2O core-shell nanocubes for the ultrasensitive determination of Escherichia coli O157:H7 in foods.

Sensitive and precise determination of virulent foodborne pathogens is significant for food safety. Herein, an ultrasensitive photoelectrochemical (PEC) bioanalysis was developed using the endogenous adenosine triphosphate (ATP)-responded Au@Cu2O core-shell nanocubes (Au@Cu2O NCs) to measure Escherichia coli O157: H7 (E. coli O157:H7) in food. Briefly, the phage-functionalized gold wire was used to specifically recognize the target pathogen. With the bacteriolysis of lysozyme, the endogenous ATP molecules were emitted from the captured target bacteria and enriched by another ATP aptamer-modified gold wire. Following the exchange with complementary DNA (cDNA) chains, the bonded ATP would be released. It could simultaneously etch the Au@Cu2O NCs and compete with external circuit electrons to combine photogenerated holes on the Au@Cu2O NCs-modified screen-printed electrode. With the synergy of the two signal amplification mechanisms, a significant attenuation of photocurrent signal appeared even with femtomolar ATP. Therefore, the purpose of ultrasensitive determination of E. coli O157:H7 was realized, which depended on the endogenous ATP rather than exogenous signal probes. The proposed biosensor presented a good analysis performance within 10-106 CFU/mL with a detection limit of 5 CFU/mL. Besides, its specificity, repeatability, and stability were also investigated and acceptable. The detection results for food samples matched well with the results detected by the plate counting method. This work gives an innovative and sensitive signal amplification strategy for PEC bioassays in foodborne pathogens detection.

[Autobiography of modern acupuncturist Yu Shu-zhuang].

Professor YU Shu-zhuang is a distinguished acupuncturist in China. He has practiced the TCM acupuncture-moxibustion clinical, educational and scientific research for 60 years in his life. In clinic, he summarized the experiences "five-ming first"; in treatment, he insisted "dredging" and "regulating", protecting the function of spleen and stomach, and needles should be less but specific. In the meanwhile, he made a deep study on the function and clinical effects of specific acupoints, and used the research results of propagated sensation along channel to guide clinical treatment, forming his special academic points. Professor YU has educated a great number of acupuncture-moxibustion talents in China and foreign countries, making great contribution to the popularization of acupuncture-moxibustion in the worldwide.

[Observation on therapeutic effect of pricking blood therapy combined with syndrome differentiation acupuncture on arthralgia syndrome].

OBJECTIVE: To observe clinical therapeutic effect of pricking blood therapy combined with acupuncture on arthralgia syndrome. METHODS: One hundred and ninety-two cases were randomly divided into a local pricking blood therapy combined with acupuncture group and a simple acupuncture control group, 96 cases in each group. Their therapeutic effects were compared. RESULTS: The cured rate and the total effective rate were 83.3% and 100.0% in the treatment group and 31.0% and 87.0% in the control group with a significant difference or a very significant difference between the two groups (P < 0.05, P < 0.01); the mean times for cure in the treatment group was superior to that in the control group (P < 0.05, P < 0.01). CONCLUSION: Pricking blood therapy combined with acupuncture has an obvious and definite therapeutic effect on arthralgia syndrome.