Investigation of bacteria and detergent residues on undergraduate students' dinner plates in dormitories during university lockdown.

The COVID-19 outbreak has disrupted undergraduate students' experiments since their access to the laboratory is limited. To address this problem, the bacteria and detergent residues on undergraduate students' dinner plates were investigated by the students in the dormitories. Five different types of dinner plates from 50 students were collected, which were cleaned with detergent and water in the same way and naturally dried. Then, Escherichia coli (E. coli) test papers and sodium dodecyl sulfonate test kits were used to understand the bacteria and detergent residuals. Commonly available equipment such as a yogurt maker was used for bacterial culture; detergent analyses were performed using centrifugation tubes. Effective sterilization methods and safety protection were achieved by dormitory available methods. According to the investigated results, the students found the differences in bacteria and detergent residuals between different dinner plates and made suitable choices for the future.

Promising instrument-free detections of various analytes using smartphones with Spotxel® Reader.

In consideration of the problems related to food safety, environmental pollution, and the spread of infected diseases nowadays, we urgently need testing methods that can be easily performed by common people. Smartphone-based detections are promising for general applications. However, some of these analytical strategies require a combination of accessories and instruments, such as portable electrochemical workstations, mini multi-mode microplate readers, and complex temperature control devices, etc., which are small but still expensive. Herein, we comprehensively introduce a free app (Spotxel® Reader) that can provide accurate data analysis for microplate or parallel-format test sensors without an instrument. By simulating the optical signal of the test samples through a smartphone, the sensing results can be obtained for free. We discuss the detection strategies involved in the reported smartphone-based analyses using Spotxel® Reader. Prospects for the development of this free app for future detection applications are presented. This review aims to popularize free analysis software, so that ordinary people may realize convenient tests.

Screening of Potential Anti-Thrombotic Ingredients from Salvia miltiorrhiza in Zebrafish and by Molecular Docking.

BACKGROUND: Danshen (DS), the dry root of Salvia miltiorrhiza Bge., has been used in traditional Chinese medicine (TCM) for many years to promote blood circulation and to inhibit thrombosis. However, the active ingredients responsible for the anti-thrombotic effect and the underlying mechanisms are yet to be fully elucidated. METHODS: Molecular docking was used to predict the active ingredients in DS and their potential targets by calculating the scores of docking between DS ingredients and thrombosis-related proteins. Then, a chemical-induced zebrafish thrombosis model was applied to confirm their anti-thrombotic effects. RESULT: The molecular docking results indicated that compared to the control ligand, higher docking scores were observed for several compounds in DS, among which salvianolic acid B (SAB), lithospermic acid (LA), rosmarinic acid (MA), and luteolin-7-O-ß-d-glucoside (LG) could attenuate zebrafish caudal vein thrombosis and recover the decrease in heart red blood cells (RBCs) in a dose-dependent manner. CONCLUSIONS: Our study showed that it is possible to screen the potential active components in natural products by combining the molecular docking method and zebrafish in vivo model.

Theoretical Exploring of a Molecular Mechanism for Melanin Inhibitory Activity of Calycosin in Zebrafish.

Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin in the human body. Overproduction of melanin can lead to a variety of skin disorders. Calycosin is an isoflavone from Astragali Radix, which is a traditional Chinese medicine that exhibits several pharmacological activities including skin whitening. In our study, the inhibitory effect of calycosin on melanin production is confirmed in a zebrafish in vivo model by comparing with hydroquinone, kojic acid, and arbutin, known as tyrosinase inhibitors. Moreover, the inhibitory kinetics of calycosin on tyrosinase and their binding mechanisms are determined using molecular docking techniques, molecular dynamic simulations, and free energy analysis. The results indicate that calycosin has an obvious inhibitory effect on zebrafish pigmentation at the concentration of 7.5 µM, 15 µM, and 30 µM. The IC50 of calycosin is 30.35 µM, which is lower than hydroquinone (37.35 µM), kojic acid (6.51 × 103 µM), and arbutin (3.67 × 104 µM). Furthermore, all the results of molecular docking, molecular dynamics simulations, and free energy analysis suggest that calycosin can directly bind to the active site of tyrosinase with very good binding affinity. The study indicates that the combination of computer molecular modeling and zebrafish in vivo assay would be feasible in confirming the result of the in vitro test and illustrating the target-binding information.