Research progress on two-component signal transduction systems in Porphyromonas gingivalis.

Porphyromonas gingivalis (P. gingivalis), a Gram-negative oral anaerobe, is considered to be a major pathogenic agent involved in the onset and progression of chronic periodontitis. P. gingivalis must be able to perceive and respond to the complicated changes in host to survive the environmental challenges, in which the two-component signal transduction systems (TCSs) play critical roles by connecting input signals to cellular physiological output. Canonical TCS consists of a sensor histidine kinase and a cognate response regulator that functions via a phosphorylation cascade. In this review, the roles of TCSs in P. gingivalis were demonstrated by illustrating the target genes and modulation modes, which may help elucidate the underlying mechanisms in future studies.

The effectiveness of formative assessment in pathophysiology education from students' perspective: a questionnaire study.

Current interdisciplinary medical training calls for reforms and innovations in the assessment of pathophysiology education. Formative assessment is used to monitor student learning to provide ongoing feedback that can improve both learning and teaching. Beginning in 2016, we implemented a formative assessment composed of case-based multiple-choice questions (MCQs) for all students in all majors. In 2017, case study questions began to be employed in the formative assessment, and student-set, case-based questions were further introduced. Aiming to gather the students' suggestions and feedback on the mixed-method assessment, we conducted a survey on aspects such as the effectiveness of the assessment, assessment content and completion, opinions on student-set questions, and the impact on pathophysiology learning for students from 2017 to 2019. In addition, we compared students' semesterly final scores with those of previous students and evaluated the relationship between formative and summative assessment scores. The results for 1,277 students clearly showed that the reformed formative assessment system was well received by the students. The students thought that the formative assessment not only allowed for the provision of real-time feedback on the effectiveness of teaching and learning but also nurtured self-motivation, the development of analytical and problem-solving skills, and collaborative efforts. Both the semesterly final scores and the proportions of students scoring in higher score ranges increased after the implementation of the formative assessment, and the summative assessment scores were positively related to the formative assessment scores. Consequently, the reformed formative assessment system significantly improved the quality of pathophysiology education.

The hydroxy-analogue of selenomethionine alleviated lipopolysaccharide-induced inflammatory responses is associated with recover expression of several selenoprotein encoding genes in the spleens of Kunming mice.

This study aimed to determine whether hydroxy-analogue of selenomethionine (HMSeBA) supplementation could alleviate LPS-induced immunological stress in mice. A total of 90 Kunming mice were randomly assigned into 5 groups. The CON-LPS and CON+LPS groups were fed basal diet (BD), the others were fed BD with different levels of HMSeBA (0.15, 0.30 and 0.45 mg Se per kg) for 4 weeks. Mice were injected with LPS (3 mg per kg BW) or the corresponding physiological saline at 14 d and 28 d. Plasma and spleens were collected at 28 d. The results showed that: (1) LPS injection decreased ADG of mice at the 3rd week, and increased the concentration of IL-6 and TNF-α in plasma and the spleen index; (2) LPS injection induced immunological stress, up-regulated 8 inflammation-related genes and 3 selenoprotein encoding genes, and down-regulated 16 selenoprotein encoding genes in spleens; (3) compared with the CON+LPS group, HMSeBA supplementation increased ADG of mice at 3 weeks and GSH-Px activity in plasma and spleens, decreased spleen index and plasma IL-6 and TNF-α levels, down-regulated mRNA levels of COX-2, ICAM-1, TNF-α, IL-6, and MCP-1, and up-regulated IL-10 and iNOS in spleens. 0.30 mg Se per kg of HMSeBA exhibited the optimal protective effect; (4) HMSeBA supplementation modestly recovered the expression of 8 selenoprotein encoding genes in the spleens of the stressed mice. The results indicated that HMSeBA supplementation alleviated LPS-induced immunological stress accompanied up-regulation of a subset of selenoprotein encoding genes in spleens of mice.

Perfluoroalkyl Substances in Water from the Yangtze River and Its Tributaries at the Dividing Point Between the Middle and Lower Reaches.

The Yangtze River drainage basins are China's most important economic development zones and also the locations of several large-scale fluorine chemical industries. In order to reveal the contribution from the tributaries at the dividing point between the middle and lower reaches of the Yangtze River with respect to perfluorinated substances (PFASs), 17 PFAS compounds in surface water, groundwater, and tap water samples were analyzed in the tributary system of the Jiujiang section of the Yangtze River. The total concentrations of PFASs in the surface waters ranged from 7.8 to 586.2 ng/L. High proportion of short-chain compound PFBS in surface waters in Nanchang City, Poyang Lake, and the Yangtze River was observed which is likely of WWTPs' origin.

Protective Effect of Selenoprotein X Against Oxidative Stress-Induced Cell Apoptosis in Human Hepatocyte (LO2) Cells via the p38 Pathway.

Oxidative stress, as mediated by ROS (reactive oxygen species), is a significant factor in initiating the cells damaged by affecting cellular macromolecules and impairing their biological functions; SelX, a selenoprotein also known as MsrB1 belonging to the methionine sulfoxide reductase (Msr) family, is the redox repairing enzyme and involved in redox-related functions. In order to more precisely analyze the relationship between oxidative stress, cell oxidative damage, and SelX, we stably overexpressed porcine Selx full-length cDNA in human normal hepatocyte (LO2) cells. Cell viability, cell apoptosis rate, intracellular ROS, and the expression levels of mRNA or protein of apoptosis-related genes under H2O2-induced oxidative stress were detected. We found that overexpression of SelX can prevent the oxidative damage caused by H2O2 and propose that the main mechanism underlying the protective effects of SelX is the inhibition of LO2 cell apoptosis. The results revealed that overexpressed SelX reduced the H2O2-induced intracellular ROS generation, inhibited the H2O2-induced upregulation of Bax and downregulation of Bcl-2, and increased the mRNA and protein ratio of Bcl-2/Bax. Furthermore, it inhibited H2O2-induced p38 MAPK phosphorylation. Taken together, our findings suggested that SelX played important roles in protecting LO2 cells against oxidative damage and that its protective effect is partly via the p38 pathway by acting as a ROS scavenger.

A novel DMAPP-responding genetic circuit sensor for high-throughput screening and evolving isoprene synthase.

High-throughput screening is a popular tool for collating biological data which would otherwise require the use of excessive resources. In this study, an artificial genetic circuit sensor responding to dimethylallyl diphosphate (DMAPP) was constructed based on a modified L-arabinose operon for high-throughput screening and isoprene synthase (ispS) evolution in Escherichia coli (E. coli). As a first step, the DNA sequence of the L-arabinose ligand-binding domain (LBD) was replaced with an ispS gene to enable the AraC operon responding to DMAPP, which is the substrate of the IspS enzyme. Then, an enhanced GFP (eGFP) was also introduced as a reporter for pBAD promoter. The expression level of the reporter was monitored using either of the two tools: flow cytometer (FCM) and microplate reader. Sequentially, we observed that a high DMAPP concentration led to low eGFP fluorescence, and the overexpression of ispS gene, which consumes DMAPP, resulted in a high eGFP expression. These results demonstrated that the artificial genetic circuit sensor responded directly to the intracellular concentration of DMAPP, and the expression of IspS enzyme could be positively correlated to the expression level of eGFP. Finally, we identified two IspS mutants with different activities from an ispS gene library and further validated the screening method.

[Case-control study on the treatment of patients with scapular muscle fasciitis by Pizhen].

OBJECTIVE: To evaluate and analyze the mechanism of Pizhen for the treatment of patients with scapular muscle fasciitis. METHODS: One hundred and sixteen patients were divided into two groups according to random number table method, 58 cases in the treatment group and 58 cases in the control group. After treatment, 109 patients were followed up, and 7 patients lost follow-up (2 cases in the treatment group and 5 patients in the control group). In the treatment group, there were 15 males and 41 females, with a mean age of (28.02 +/- 4.85) years; the course of disease ranged from 0.25 to 3 years; and the patients were treated by Pizhen once a week,and 2 weeks were one treatment course. In the control group, there were 19 males and 34 females, with a mean age of (27.23 +/- 4.54) years old; the course of disease ranged from 0.25 to 1 year; and the patients were treated by acupuncture massage instrument, 20 minutes at a time,once a day for 2 weeks. Soft tissue displacement and banana area were tested by a soft tissue tension tester, pressure value was measured by pressure measuring instrument, and VAS was recorded by pain visual analog scale record. RESULTS: There were significant differences in tissue displacement, banana area, pressure value and VAS between two groups before and after treatment. The tissue displacement and pressure value in the treatment group were higher than those in the control group,while banana area and VAS were lower than those in the control group. In the treatment group, 30 patients healed, 13 patients got marked improvement, 12 good and 1 poor;while 16 patients healed, 19 patients got marked improvement,11 good and 7 poor in the control group. The therapeutic effects in the treatment group was better than that in the control group. CONCLUSION: Pizhen is an effective method to treat pain in patients with scapular muscle fasciitis by relaxing tendon of soft tissue around pain point of scapular and relaxing compress and stimulation of nerves.