ABSTRACT
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 HapR.@*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 HapR 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 HapR.@*CONCLUSION@#Overexpressed VCA0560 functions as an active DGC in V. cholerae, and its transcription is repressed by Fur and HapR.
Subject(s)
Vibrio cholerae/genetics , Biofilms , Quorum Sensing , Mutation , Gene Expression Regulation, Bacterial , Bacterial Proteins/geneticsABSTRACT
Cardiac arrest during upper abdominal surgery such as liver transplantation is a rare but very severe complication. Traditional external cardiac compression has been the mainstay of basic life support in general circumstances. Subdiaphragmatic cardiac compression (SDCC), with no incision in the diaphragm, may be a more effective measure. This maneuver can provide more effective and timely cardiac compression via the already open abdomen in surgery and not add extra trauma. This method can provide a quicker and more effective means of circulation support for intraoperative cardiac arrest patients without adding new injuries. Five cases are reported and all the patients had return of spontaneous circulation (ROSC). This is the first report of the SDCC method.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Cardiopulmonary Resuscitation , Methods , Heart Arrest , Therapeutics , Liver TransplantationABSTRACT
<p><b>OBJECTIVE</b>This study is to verify the use of rich BHI medium to substitute synthetic media for gene regulation studies in Yersinia pestis.</p><p><b>METHODS</b>The transcriptional regulation of rovA by PhoP or via temperature upshift, and that of pla by CRP were investigated when Y. pestis was cultured in BHI. After cultivation under 26 °C, and with temperature shifting from 26 to 37 °C, the wild-type (WT) strain or its phoP or crp null mutant (ΔphoP or Δcrp, respectively) was subject to RNA isolation, and then the promoter activity of rovA or pla in the above strains was detected by the primer extension assay. The rovA promoter-proximal region was cloned into the pRW50 containing a promoterless lacZ gene. The recombinant LacZ reporter plasmid was transformed into WT and ΔphoP to measure the promoter activity of rovA in these two strains with the β-Galactosidase enzyme assay system.</p><p><b>RESULTS</b>When Y. pestis was cultured in BHI, the transcription of rovA was inhibited by PhoP and upon temperature upshift while that of pla was stimulated by CRP.</p><p><b>CONCLUSION</b>The rich BHI medium without the need for modification to be introduced into the relevant stimulating conditions (which are essential to triggering relevant gene regulatory cascades), can be used in lieu of synthetic TMH media to cultivate Y. pestis for gene regulation studies.</p>