Regulatory effect of isovitexin on MAPK/NF-κB signal in mice with acute ulcerative colitis.

The aim of this study was to investigate the anti-inflammatory effects and mechanism of isovitexin on ulcerative colitis mice and RAW264.7 cells. The results showed that isovitexin had strong antioxidant and anti-inflammatory effects, and could restore intestinal barrier integrity (p < 0.01). In addition, isovitexin inhibited the expression of MyD88, TLR4 and NF-κB p65 proteins. At the same time, isovitexin can inhibit the activation of MAPK/NF-κB signaling pathway in RAW264.7 cells. In conclusion, isovitexin has a protective effect on UC mice, and its improvement mechanism of UC might be related to MAPK/NF-κB signaling pathway.

Impact of the COVID-19 pandemic on career intention amongst undergraduate medical students: a single-centre cross-sectional study conducted in Hubei Province.

BACKGROUND: Undergraduate medical (UM) students faced the difficulties inherent in medical careers due to the coronavirus (COVID-19) outbreak. Thus, imperative containment measures might affect UM students' career intentions. Information on the factors that may be associated with these students' career change intentions is limited. METHODS: We conducted a cross-sectional survey in August 2020 to investigate the impact of the COVID-19 pandemic on career intention and the associated factors in UM students. Univariate analyses and logistic regression analysis were performed to identify said factors. RESULTS: A total of 2040 medical students from the Hubei University of Medicine were surveyed. Univariate analyses showed that grade, attitude towards healthcare, and the degree of the COVID-19 pandemic's impact on the students' lives were associated with changes in career choice (P<0.05). Logistic regression analysis showed that Grade 2, Grade 5, attitude towards a medical career, and having relatives with a medical background were associated with changes in career choice. The degree of the COVID-19 pandemic's impact was a common and significant factor associated with career preference, career perspective, and ideal workplace. CONCLUSIONS: Changes in career intentions were particularly influenced by grade, attitude towards being a health worker, and the degree of COVID-19's impact on the participants' lives. Treating large-scale public health emergencies rationally, setting up correct views of occupation choice, and building reasonable career planning may reduce the loss of medical talent.

Response to Multiple Stressors: Enhanced Tolerance of Neoseiulus barkeri Hughes (Acari: Phytoseiidae) to Heat and Desiccation Stress through Acclimation.

Organisms are always confronted with multiple stressors simultaneously. Combinations of stressors, rather than single stressor, may be more appropriate in evaluating the stress they experience. N. barkeri is one of predatory mite species that are commercialized for controlling spider mites. However, their biological control efficiency was often reduced because of high temperature and desiccation in summer. To understand how to improve the tolerance of N. barkeri to combined heat and desiccation stress, we pre-exposed the adult female of N. barkeri to high temperature, desiccation and high temperature × desiccation stress for acclimation. After proper recovery time, mites were subjected to high temperature × desiccation stress again to detect the acclimation effects. The results are as follows: (1) No decrease in mortality rate were observed under high temperature × desiccation stress after heat acclimation. Instead, it increased significantly with acclimation temperature and time. (2) Dehydration acclimation both at 25 °C and high temperatures reduced mortality rate under high temperature × desiccation stress. Mortality rate was only significantly correlated with the amount of water loss, but not with temperature or water loss rate in acclimation, suggesting the increased tolerance is related to dehydration stress rather than heat stress. Among all acclimations, chronic dehydration at 25 °C, 50% relative humidity were the most effective treatment. This study indicated dehydration acclimation is effective to enhance tolerance of N. barkeri to combined heat and desiccation stress, which can improve the efficiency of biological control under multiple stressors.

Rapid and label-free fluorescence bioassay for microRNA based on exonuclease III-assisted cycle amplification.

The quantitative analysis of microRNA is extremely important in biological research and clinical diagnosis due to the relationship between microRNA and disease. In this study, we reported a new assay for the rapid and simple detection of microRNA based on G-quadruplex and exonuclease III (ExoIII) dual signal amplification. We specifically designed two hairpins with G-quadruplex sequence. In the absence of a target, the G-quadruplex sequences are enclosed in the hairpin and fluorescence signal shut down. However, when a target is added, the dual cycle is carried out because two hairpins are digested and X and Y sequences are released under the action of ExoIII. Then, these released sequences form the G-quadruplex sequence, and N-methylmorpholine (NMM) is embedded in the G-quadruplex to produce strong fluorescence. The linear range is from 2.5 × 10-10 to 4 × 10-9 mol L-1 with a low detection limit of 6 pM. Compared to some of the previous strategies, this bioassay needs only a simple one-step reaction, and is easy for realizing the rapid detection of microRNAs. The time required for the entire analysis is only 1 hour. In addition, this bioassay has good specificity and can be applied to the actual samples.

Evaluation of Neoseiulus barkeri (Acari: Phytoseiidae) for Control of Eotetranychus kankitus (Acari: Tetranychidae).

Eotetranychus kankitus Ehara (Acari: Tetranychidae) is an important pest in Chinese citrus orchards. In the present study, we aimed to evaluate the potential of Neoseiulus barkeri (Hughes) (Acari: Phytoseiidae) for the biological control of E. kankitus. A two-sex life table of E. kankitus and N. barkeri was constructed to estimate development and fecundity. The functional response and stage-specific predation rate were analyzed to evaluate predation capacity. In addition, a timing model was used to project populations of E. kankitus with release of N. barkeri. Results showed that N. barkeri was able to develop and reproduce when fed on E. kankitus. The functional responses of N. barkeri on different stages of E. kankitus all fit the Holling II disc equation. When mixed stages of E. kankitus coexisted, N. barkeri mainly consumed larvae and nymphs. Based on the life tables and stage-specific predation rates, population projection revealed the stage structure and growth rate of N. barkeri on E. kankitus. Although E. kankitus had the higher growth rate, it was maintained at a low population level for several weeks after release of N. barkeri. The results highlighted the potential for utilizing N. barkeri as a biological control agent of E. kankitus.

Does Long-Term Feeding on Alternative Prey Affect the Biological Performance of Neoseiulus barkeri (Acari: Phytoseiidae) on the Target Spider Mites?

The predatory mite Neoseiulus barkeri (Hughes) is a good biological control agent for many small sucking pests. We aimed to determine whether rearing long term on alternative prey versus target prey species affected the performance of N. barkeri. Therefore, we investigated the prey preference, life tables, and population parameters of N. barkeri between alternative prey Tyrophagus putrescentiae (Schrank) and three species of spider mites, Tetranychus urticae Koch, Panonychus citri (McGregor), and Eotetranychus kankitus Ehara. We found that N. barkeri preferred the tetranychid mites to the alternative prey. Between the tetranychid mites, the predator consumed more P. citri and E. kankitus than T. urticae. When reared on T. urticae, the total developmental time and longevity of N. barkeri were the longest, whereas the intrinsic rate of increase was the lowest, indicating that the biotic fitness of predatory mite preyed on target of T. urticae was higher than on alternative prey of T. putrescentiae. However, total developmental time, longevity, and fecundity did not differ between N. barkeri reared on T. putrescentiae and P. citri, although these parameters were higher than those for mites reared on E. kankitus, indicating that the predatory mite reared on T. putrescentiae may not be affected to control P. citri, and that coexistence of P. citri and E. kankitus may enhance the control efficiency of N. barkeri. Altogether, our results demonstrated that long-term feeding on the alternative prey T. putrescentiae did not affect the performance of the predatory mite N. barkeri on various target spider mites.

Theoretical study of the cooperative effects between the triel bond and the pnicogen bond in BF3···NCXH2···Y (X = P, As, Sb; Y = H2O, NH3) complexes.

The interplay between the triel bond and the pnicogen bond in BF3···NCXH2···Y (X = P, As, Sb; Y = H2O, NH3) complexes was studied theoretically. Both bonds exhibited cooperative effects, with shorter binding distances, larger interaction energies, and greater electron densities found for the ternary complexes than for the corresponding binary ones. The cooperative effects between the triel bond and the pnicogen bond were probed by analyzing molecular electrostatic potentials, charge transfer, and orbital interactions. The results showed that the enhancement of the triel bond can mainly be attributed to the electrostatic interaction, while the strengthening of the pnicogen bond can be ascribed chiefly to the electrostatic and orbital interactions. In addition, the origins of both the triel bond and the pnicogen bond were deduced via energy decomposition.