ABSTRACT
Most bacteria possess alcohol dehydrogenase (ADH) genes (Adh genes) to mitigate alcohol toxicity, but these genes have functions beyond alcohol degradation. Previous research has shown that ADH can modulate quorum sensing in Acinetobacter baumannii, a rising opportunistic pathogen. However, the number and nature of Adh genes in A. baumannii have not yet been fully characterized. We identified seven alcohol dehydrogenases (NAD+-ADHs) from A. baumannii ATCC 19606, and examined the roles of three iron-containing ADHs, ADH3, ADH4, and ADH6. Marker-less mutation was used to generate Adh3, Adh4, and Adh6 single, double, and triple mutants. Disrupted Adh4 mutants failed to grow in ethanol-, 1-butanol-, or 1-propanol-containing mediums, and recombinant ADH4 exhibited strongest activity against ethanol. Stress resistance assays with inorganic and organic hydroperoxides showed that Adh3 and Adh6 were key to oxidative stress resistance. Virulence assays performed on the Galleria mellonella model organism revealed that Adh4 mutants had comparable virulence to wild-type, while Adh3 and Adh6 mutants had reduced virulence. The results suggest that ADH4 is primarily involved in alcohol metabolism, while ADH3 and ADH6 are key to stress resistance and virulence. Further investigation into the roles of other ADHs in A. baumannii is warranted.
Subject(s)
Acinetobacter baumannii/enzymology , Acinetobacter baumannii/pathogenicity , Alcohol Dehydrogenase/metabolism , Iron/metabolism , Stress, Physiological , Acinetobacter baumannii/genetics , Acinetobacter baumannii/physiology , Alcohol Dehydrogenase/chemistry , Alcohol Dehydrogenase/genetics , Amino Acid Sequence , Animals , Computer Simulation , Cytosol/metabolism , Ethanol/pharmacology , Gene Expression Regulation, Bacterial/drug effects , Genes, Bacterial , Homeostasis/drug effects , Hydrogen-Ion Concentration , Melanins/metabolism , Moths/microbiology , Mutation/genetics , Oxidative Stress/drug effects , Phylogeny , VirulenceABSTRACT
The purpose of this study is to demonstrate an application of the many-facet Rasch model (MFRM) in evaluating the impromptu speech skills of pre-service principals in Taiwan. The findings showed that the topics of speech did not exhibit different difficulty measures. With respect to scoring criteria, time control was the most difficult aspect among the scoring criteria. Regarding gender difference in raters, female raters gave lower scores than male raters, but there was no statistical evidence for gender-related bias. However, raters exhibited statistically significant differences in rater severity. The results of this study demonstrates that the MFRM provides a scientific approach to assessment, which can reveal some useful diagnostic information from the original ordinal rating scores on impromptu speech.
Subject(s)
Educational Personnel , Psychometrics , Schools , Speech , Female , Humans , Male , TaiwanABSTRACT
"Jinchuang ointment" is a traditional Chinese herbal medicine complex for treatment of incised wounds. For more than ten years, it has been used at China Medical University Hospital (Taichung, Taiwan) for the treatment of diabetic foot infections and decubitus ulcers. Three different cases are presented in this study. "Jinchuang" ointment is a mixture of natural product complexes from nine different components, making it difficult to analyze its exact chemical compositions. To further characterize the herbal ingredients used in this study, the contents of reference standards present in a subset of the ointment ingredients (dragon's blood, catechu, frankincense, and myrrh) were determined by HPLC. Two in vitro cell based assay platforms, wound healing and tube formation, were used to examine the biological activity of this medicine. Our results show that this herbal medicine possesses strong activities including stimulation of angiogenesis, cell proliferation, and cell migration, which provide the scientific basis for its clinically observed curative effects on nonhealing diabetic wounds.
