Accelerating Cell-Free Biosensors by Entropy-Driven Assembly of Transcription Templates.

Due to its high efficiency and selectivity, cell-free biosynthesis has found broad utility in the fields of bioproduction, environment monitoring, and disease diagnostics. However, the practical application is limited by its low productivity. Here, we introduce the entropy-driven assembly of transcription templates as dynamic amplifying modules to accelerate the cell-free transcription process. The catalytic DNA circuit with high sensitivity and enzyme-free format contributes to the production of large amounts of transcription templates, drastically accelerating the as-designed cell-free transcription system without interference from multiple enzymes. The proposed approach was successfully applied to the ultrasensitive detection of SARS-CoV-2, improving the sensitivity by 3 orders of magnitude. Thanks to the high programmability and diverse light-up RNA pairs, the method can be adapted to multiplexing detection, successfully demonstrated by the analysis of two different sites of the SARS-CoV-2 gene in parallel. Further, the flexibility of the entropy-driven circuit enables a dynamic responding range by tuning the circuit layers, which is beneficial for responding to targets with different concentration ranges. The strategy was also applied to the analysis of clinical samples, providing an alternative for sensitively detecting the current SARS-CoV-2 RNA that quickly mutates.

A functional RNA/DNA circuit for one-pot detection of SARS-CoV-2 RNA.

A simple method is proposed in this work for the detection of SARS-CoV-2 RNA based on a functional RNA/DNA circuit. By ingeniously integrating the nucleic acid circuit technology and CRISPR/cas12a system, this method can achieve femtomolar detection of the target RNA in one step and successfully distinguish COVID-19 positive cases from clinical samples, proving its great potential for clinical application.

Outbreak of Haff Disease along the Yangtze River, Anhui Province, China, 2016.

We investigated a large outbreak of Haff disease that occurred along the Yangtze River in Anhui Province, China, in 2016. Of the 672 cases identified during the outbreak, 83.3% (560/672) occurred in Wuhu and Ma'anshan. Patients experienced myalgia (100%) and muscle weakness (54.7%). The mean value of myoglobin was 330 + 121.2 ng/mL and of serum creatine kinase 5,439.2 + 4,765.1 U/L. Eating crayfish was the only common exposure among all cases; 96.8% (240/248) of implicated crayfish were caught on the shores of the Yangtze River or its connected ditches. Mean incubation period was 6.2 + 3.8 hours. This case-control study demonstrated that eating the liver of crayfish and eating a large quantity of crayfish were associated with an increased risk for Haff disease. The seasonal increases in crayfish population along the Yangtze River might explain the seasonal outbreaks of Haff disease.

[Polymorphism of XRCC1 and chromosome damage in workers occupationally exposed to benzene].

OBJECTIVE: To explore the relationship between the polymorphisms of DNA repair gene (XRCC1 194, 280 and 399) and the chromosomal damage induced by benzene. METHODS: The chromosomal damage of the peripheral lymphocytes in 459 workers occupationally exposed to benzene and 88 non-exposed controls were detected with cytokinesis-block micronucleus (CBMN) assay. PCR-RFLP technique was used to measure polymorphisms in XRCC1 194, 280 and 399. RESULTS: It was found that the MN frequency (2.12‰ ± 1.88‰) of the exposed group was significantly higher than that (1.19‰ ± 1.68‰) of the control group (P < 0.05), in the exposed group, the MN frequency (3.00‰ ± 2.76‰) of older workers (> 35 years) was significantly higher than that (2.02‰ ± 1.71‰) of younger workers (≤ 35 years) (P < 0.05). The effect of genetic polymorphisms of XRCC1 on CBMN was not found. The haplotypes AAA/BAA, AAB/AAB, ABA/ABA, ABB/ABB could associated with the increased frequencies of total micronucleus (P < 0.05). CONCLUSION: Benzene exposure could result in chromosome damage. Age of workers and diplotypes of XRCC1 could associated with chromosomal damage induced by benzene.