Live-Cell Sensing of Telomerase Activity by Using Hybridization-Sensitive Fluorescent Oligonucleotide Probes.

Live-cell sensing of telomerase activity with simple and efficient strategies remains a challenging target. In this work, a strategy for telomerase sensing by using hybridization-sensitive fluorescent oligonucleotide probes is reported. In the presence of telomerase and dNTPs, the designed supporting strand was extended and generated the hairpin structure that catalyzed the next telomerase extending reaction. The special extension mechanism increased the local concentration of another supporting strand and telomerase, which resulted in enhanced telomerase activity. The hybridization-sensitive oligonucleotide probes bound to the hairpin catalyst and generated turn-on fluorescence. This method realized the sensing of telomerase activity in HeLa cell extract with a detection limit below 1.6×10-6  IU µL-1 . The real-time in situ observation of telomerase extension was achieved in living HeLa cells. This strategy has been applied to monitor the efficiency of telomerase-targeting anticancer drugs in situ.

Annual variation in domoic acid in phytoplankton and shellfish samples from Daya Bay of the South China Sea.

Domoic acid (DA) is a well-known phycotoxin that causes amnesic shellfish poisoning (ASP) and is mainly produced by diatom species belonging to the genus Pseudo-nitzschia. An annual survey was conducted monthly over the period of September 2020 to August 2021 in Daya Bay of the South China Sea to investigate the dynamics of particulate and shellfish DA and their relationships with the abundance of Pseudo-nitzschia spp. and environmental parameters. Pseudo-nitzschia spp. was one of the most dominant phytoplankton taxa, and a Pseudo-nitzschia bloom occurred during the survey with the highest abundance of 1.91 × 106 cells L-1. DA was detected in almost all plankton samples with the highest value of 120.7 ng L-1, and high DA concentrations coincided with the abundant presence of Pseudo-nitzschia. DA is prevalent in Daya Bay throughout the year, with detection rates of 98.3%, 82.6%, and 82.6% in plankton samples, in-situ and purchased shellfish, respectively. Higher DA concentrations were detected in the scallop (Chamys nobilis), with the highest concentration of 5.34 µg g-1. High water temperature and low DSi:DIN ratio promoted the growth of Pseudo-nitzschia and DA production. The results suggest that the increasing nitrogen loading and silicate limitation during Pseudo-nitzschia blooms together with the increase in water temperature may increase the risk of DA contamination in Daya Bay.

Experimental study on full-volume slag alkali-activated mortars: Air-cooled blast furnace slag versus machine-made sand as fine aggregates.

As the industrial waste from blast furnace ironmaking, air-cooled blast furnace slag (ACBFS) puts a lot of pressure on the environment. It is becoming more and more urgent to deal with the increasing ACBFS. In this study, the concept of "full-volume slag alkali-activated mortars (FSAM)" is proposed using ground granulated water-cooled blast furnace slag (GGBS) as aluminosilicate material and ACBFS to replace machine-made sand, aiming to solve the current situation of increasing scarcity of natural resources. The characteristics of ACBFS are investigated, and its stability and heavy metal leaching all meet the requirements as a building material. The results show that the flowability and mechanical properties of FSAM are significantly enhanced with the substitution rate of ACBFS increases. Meanwhile, the incorporation of ACBFS is also beneficial to improve the compactness of the microstructure of the mortar, thereby improving the impermeability (Water, ion and gas) of FSAM. In addition, the specimen mixed with ACBFS showed good high temperature resistance due to the porous feature of the aggregate. Furthermore, using a small amount of limestone powder to replace GGBS can slightly improve the performance of FSAM. Therefore, ACBFS is recommended to be used in FSAM, which meets safety, cost and environmental benefits.