Efficient markerless genetic manipulation of Pasteurella multocida using lacZ and pheSm as selection markers.

Pasteurella multocida is a zoonotic conditional pathogen that infects multiple livestock species, causing substantial economic losses in the animal husbandry industry. An efficient markerless method for gene manipulation may facilitate the investigations of P. multocida gene function and pathogenesis of P. multocida. Herein, a temperature-sensitive shuttle vector was constructed using lacZ as a selection marker, and markerless glgB, opa, and hyaE mutants of P. multocida were subsequently constructed through blue-white colony screening. The screening efficiency of markerless deletion strains was improved by the lacZ system, and the method could be used for multiple gene deletions. However, the fur mutant was unavailable via this method. Therefore, we constructed a pheSm screening system based on mutated phenylalanine tRNA synthetase as a counterselection marker to achieve fur deletion mutant. The transformed strain was sensitive to 20 mM p-chloro-phenylalanine, demonstrating the feasibility of pheSm as a counter-selective marker. The pheSm system was used for markerless deletions of glgB, opa, and hyaE as well as fur that could not be screened by the lacZ system. A comparison of screening efficiencies of the system showed that the pheSm counterselection system was more efficient than the lacZ system and broadly applicable for mutant screening. The methods developed herein may provide valuable tools for genetic manipulation of P. multocida.IMPORTANCEPasteurella multocida is a highly contagious zoonotic pathogen. An understanding of its underlying pathogenic mechanisms is of considerable importance and requires efficient species-specific genetic tools. Herein, we propose a screening system for P. multocida mutants using lacZ or pheSm screening markers. We evaluated the efficiencies of both systems, which were used to achieve markerless deletion of multiple genes. The results of this study support the use of lacZ or pheSm as counterselection markers to improve counterselection efficiency in P. multocida. This study provides an effective genetic tool for investigations of the virulence gene functions and pathogenic mechanisms of P. multocida.

Effectiveness of Exergaming in Improving Cognitive and Physical Function in People With Mild Cognitive Impairment or Dementia: Systematic Review.

BACKGROUND: Individuals with mild cognitive impairment and dementia have impaired physical and cognitive functions, leading to a reduced quality of life compared with those without such impairment. Exergaming, which is defined as a combination of exercise and gaming, is an innovative, fun, and relatively safe way to exercise in a virtual reality or gaming environment. Therefore, exergaming may help people living with mild cognitive impairment or dementia to overcome obstacles that they may experience regarding regular exercise and activities. OBJECTIVE: The aim of this systematic review was to review studies on exergaming interventions administered to elderly individuals with mild cognitive impairment and dementia, and to summarize the results related to physical and cognitive functions such as balance, gait, executive function, and episodic memory. METHODS: We searched Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, PsycINFO, Amed, and Nursing Database for articles published from the inception of the respective databases to January 2019. We included all clinical trials of exergaming interventions in individuals with mild cognitive impairment and dementia for review. The risk of bias was independently evaluated by two reviewers using the Cochrane Collaboration and Risk of Bias in Non-randomized Studies of Interventions tools. RESULTS: Ten studies involving 702 participants were included for review. There was consistent evidence from 7 studies with a low risk of bias showing statistically significant effects of exergaming on cognitive functioning in people with mild cognitive impairment and dementia. With respect to physical function, 3 of 5 full-scale studies found positive results, and the intensity of most games was classified as moderate. CONCLUSIONS: Overall, exergaming is an innovative tool for improving physical and cognitive function in people with mild cognitive impairment or dementia, although there is high heterogeneity among studies in terms of the duration, frequency, and gaming platform used. The quality of the included articles was moderate to high. More high-quality studies with more accurate outcome indicators are needed for further exploration and validation of the benefits of exergaming for this population.

[Study on fingerprint chromatograms of extract of cimicifugae rhizoma].

OBJECTIVE: To establish the fingerprint chromatograms of the extract of Cimicifugae Rhizoma firstly. METHOD: Phenolic acids and triterpenoid saponins were analyzed by HPLC. Hypersil BDS C18 (4.6 mm x 250 mm, 5 microm) column was used, the mobile phase was composed of acetonitrile -0.1% H3PO4 with gradient elution, flow rate was 1.0 mL x min(-1), column temprature was 30 degrees C, and the detection wavelength was set at 316 nm and 210 nm. RESULT: In the fingerprint of phenolic acids, thirteen feature peaks were found and the RSD of relative retention time and relative peak area were all less than 3% in the precision and repeation experiments. The similarity of ten batches of samples were all more than 0.90. In the fingerprint of triterpenoid saponins, fourteen feature peaks were found and the RSD of relative retention time and relative peak area were all less than 4% in the precision and repeation experiments. The similarity of ten batches of samples were all more than 0.90. CONCLUSION: This method is comprehensive, stable, reliable and can be used to evaluate the quality of the extract of Cimicifugae Rhizoma. It has provided a reference to the analysis on pharmacodynamic deferences of Cimicifuga extracts and also laid the foundation for its further development.