Objective This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase(DGC)in Vibrio cholerae and how its transcription is regulated by Fur and Hap R.Methods The roles of VCA0560 was ...Objective This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase(DGC)in Vibrio cholerae and how its transcription is regulated by Fur and Hap R.Methods The roles of VCA0560 was investigated by utilizing various phenotypic assays,including colony morphological characterization,crystal violet staining,Cyclic di-GMP(c-di-GMP)quantification,and swimming motility assay.The regulation of the VCA0560 gene by Fur and Hap R was analyzed by luminescence assay,electrophoretic mobility shift assay,and DNase I footprinting.Results VCA0560 gene mutation did not affect biofilm formation,motility,and c-di-GMP synthesis in V.cholerae,and its overexpression remarkably enhanced biofilm formation and intracellular c-di-GMP level but reduced motility capacity.The transcription of the VCA0560 gene was directly repressed by Fur and the master quorum sensing regulator Hap R.Conclusion Overexpressed VCA0560 functions as an active DGC in V.cholerae,and its transcription is repressed by Fur and Hap R.展开更多
This study evaluated the effects of dietary fat levels on the growth, nutrient digestibility, nitrogen balance and pelt characteristics of the blue fox(Alopex lagopus). Age-matched blue foxes(12 weeks old) with simila...This study evaluated the effects of dietary fat levels on the growth, nutrient digestibility, nitrogen balance and pelt characteristics of the blue fox(Alopex lagopus). Age-matched blue foxes(12 weeks old) with similar body weights were randomly divided into six dietary groups over 98 days, during the growing-furring period. Blue foxes in the six groups were fed with experimental diets containing 10%(groupⅠ), 12%(groupⅡ), 14%(group Ⅲ), 16%(group Ⅳ), 18%(groupⅤ) and 20%(group Ⅵ) fat during the growing period(from 13 weeks to 18 weeks of age);foxes were fed with diets containing 12%(groupⅠ), 14%(groupⅡ), 16%(group Ⅲ), 18%(group Ⅳ), 20%(groupⅤ) and 22%(group Ⅵ) fat during the furring period(from 18 weeks to 26 weeks of age). The results indicated that 16%-18% dietary fat, during the growing period significantly improved nutrient utilization, and as a main energy source, significantly reduced the feed/gain ratio. A dietary fat level of 18%, during the furring period not only improved the growth and development and decreased the feed/gain ratio, but also increased nutrient digestibility and fur quality. These data, combined with data from a conic regression model, showed that dietary fat levels between 16.29% and 18.40%, during the growing period and between 17.72% and 18.72%, during the furring period enhanced the growth performance and fur quality of blue foxes.展开更多
基金supported by grants from the National Natural Science Foundation of China[Grant No.81471917]the National Basic Research Priorities Program[Grant 2015CB554201]the Science Foundation for the State Key Laboratory for Infectious Disease Prevention and Control of China[Grant No.2015SKLID509]
文摘Objective This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase(DGC)in Vibrio cholerae and how its transcription is regulated by Fur and Hap R.Methods The roles of VCA0560 was investigated by utilizing various phenotypic assays,including colony morphological characterization,crystal violet staining,Cyclic di-GMP(c-di-GMP)quantification,and swimming motility assay.The regulation of the VCA0560 gene by Fur and Hap R was analyzed by luminescence assay,electrophoretic mobility shift assay,and DNase I footprinting.Results VCA0560 gene mutation did not affect biofilm formation,motility,and c-di-GMP synthesis in V.cholerae,and its overexpression remarkably enhanced biofilm formation and intracellular c-di-GMP level but reduced motility capacity.The transcription of the VCA0560 gene was directly repressed by Fur and the master quorum sensing regulator Hap R.Conclusion Overexpressed VCA0560 functions as an active DGC in V.cholerae,and its transcription is repressed by Fur and Hap R.
基金Supported by the Harbin Applied Technology Research and Development Project(2016RAXXJ015)
文摘This study evaluated the effects of dietary fat levels on the growth, nutrient digestibility, nitrogen balance and pelt characteristics of the blue fox(Alopex lagopus). Age-matched blue foxes(12 weeks old) with similar body weights were randomly divided into six dietary groups over 98 days, during the growing-furring period. Blue foxes in the six groups were fed with experimental diets containing 10%(groupⅠ), 12%(groupⅡ), 14%(group Ⅲ), 16%(group Ⅳ), 18%(groupⅤ) and 20%(group Ⅵ) fat during the growing period(from 13 weeks to 18 weeks of age);foxes were fed with diets containing 12%(groupⅠ), 14%(groupⅡ), 16%(group Ⅲ), 18%(group Ⅳ), 20%(groupⅤ) and 22%(group Ⅵ) fat during the furring period(from 18 weeks to 26 weeks of age). The results indicated that 16%-18% dietary fat, during the growing period significantly improved nutrient utilization, and as a main energy source, significantly reduced the feed/gain ratio. A dietary fat level of 18%, during the furring period not only improved the growth and development and decreased the feed/gain ratio, but also increased nutrient digestibility and fur quality. These data, combined with data from a conic regression model, showed that dietary fat levels between 16.29% and 18.40%, during the growing period and between 17.72% and 18.72%, during the furring period enhanced the growth performance and fur quality of blue foxes.
