A Precise and Portable Detection System for Infectious Pathogens Based on CRISPR/Cas Technology / 分析化学

Nucleic acid-based molecular diagnostic methods are considered the gold standard for detecting infectious pathogens.However,when applied to portable or on-site rapid diagnostics,they still face various limitations and challenges,such as poor specificity,cumbersome operation,and portability difficulties.The CRISPR(Clustered regularly interspaced short palindromic repeats)/CRISPR-associated protein(Cas)-fluorescence detection method holds the potential to significantly enhance the specificity and signal-to-noise ratio of nucleic acid detection.In this study,we developed a portable grayscale reader detection system based on loop-mediated isothermal amplification(LAMP)-CRISPR/Cas.On one hand,in the presence of CRISPR RNA(crRNA),the CRISPR/Cas12a system was employed to achieve precise fluorescent detection of self-designed LAMP amplification reactions for influenza A and influenza B viruses.This further validated the high selectivity and versatility of the CRISPR/Cas system.On the other hand,the accompanying independently developed portable grayscale reader allowed for low-cost collection of fluorescence signals and high-reliability visual interpretation.At the end of the detection process,it directly provided positive or negative results.Practical sample analyses using this detection system have verified its reliability and utility,demonstrating that this system can achieve highly sensitive and highly specific portable analysis of influenza viruses.

Adaption and Optimization of Universal Hairpin Transduction in Gene Diagnostics Based on Nucleic Acid Circuits / 分析化学

Isothermal nucleic acid amplifications, as powerful as polymerase chain reaction but functioning at a constant temperature, are considered to be very promising technique in achieving point-of-care gene diagnostics. However, until now, their practical applications are still seriously lagged by the bad reliability resulting from the problems such as false positive amplification and low signal amplitude. In this work, a universal transduction method in which any sequence ( including loop-mediated isothermal amplification products) could be transduced via a hairpin transducer into a catalyst of a well-engineered circuit (catalytic hairpin assembly, CHA) was established. Because CHA circuit could amplify tens to hundreds fold with especially high sequence specificity, it could provide both accuracy and high amplitude for sequence detection. And for a new targeting sequence, the only sequence needed to be changed was the hairpin transducer. Due to the importance of the transducer, we provided and verified a universal designing rule-set to guarantee the transducing efficiency ( signal to background ratio) of the transducer. Transducers designed following this rule set were then proved to be very efficient in detecting pathogen gene targets. As less as near single molecule ( 20 copies ) of pathogen genes could be detected with significant fluorescent and electrochemical signals.

A comparison study on stigma of schizophrenia in remission between outpatients and inpatients / 预防医学

Objective To analyze the influence of different therapeutic environments on stigma of schizophrenia patients. Methods A total of 70 outpatients and 70 inpatients with schizophrenia in remission in Tongde hospital of Zhejiang province were enrolled and investigated by using Brief Psychiatric Rating Scale (BPRS),Positive and Negative Syndrome Scale (PANSS),Treatment Emergent Symptom Scale (TESS)and Clinician's Global Impressions-Severity of Illness Scale (CGI-SI).Results Both outpatients and inpatients had been discriminated and had the situation of stigma and disease concealing.After inpatient treatment,the scores of disease concealing factor and positive effect factor were 2.01 ±0.88 and 1.68 ±0.78 respectively,which were significantly lower than those of outpatients (2.43 ±0.98 and 2.44 ±0.78, respectively,P<0.05 ).Conclusion Outpatient treatment has the influence on reduce stigma and improve the life quality of schizophrenia patients in remission.

Detection of beef contaminated by bovine central nervous system tissue by enzyme immunoassay / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study influencing factors of detection of bovine central nervous system (CNS) tissue contaminated beef by enzyme immunoassay (EIA), and the method was applied to the detection of imported beef and domestic beef of China.</p><p><b>METHODS</b>Raw beef homogenates containing different concentrations of raw CNS tissue and the same samples which were heated were detected after different time by RIDASCREEN(r) Risk Material 10/5 and RIDASCREEN(r) Probennahme- zubehor Sampling tools kits. PBS suspension and sample dilution buffer (SDB) suspension of bovine brain tissue with the same concentration of the standard were detected. Beef from USA and domestic market of China were then detected by the kits.</p><p><b>RESULTS</b>The kits could detect both raw and heated CNS tissue in the products with high sensitivity. The absorbance values (AV) increased with the concentrations of CNS in samples. Heating and increasing of time could decrease the absorbance values of the samples which contain CNS tissue. The AV of the PBS suspension of bovine brain tissue was higher than the SDB suspension and the AV of both were higher than the AV of standard of the same concentration. No CNS tissue was detected from all imported beef. No CNS tissue was detected in all samples from domestic market of China except for foxtail.</p><p><b>CONCLUSION</b>The EIA method has high sensitivity for detection of bovine CNS tissue contaminated beef with the glial fibrillary acidic protein (GFAP) as accurate target substance. Heating and increasing of time can lead to decreasing of the AV of samples. Improper slaughter process can lead to contamination of bovine products by bovine CNS tissue.</p>