The objective of this study was to characterize the effects of silver nanoparticles on Pseudomonas aeruginosa. Their interactions with several conventional antibiotics and ability to induce a stress response were examined. Interactions between silver nanoparticles (AgNPs) and antibiotics against free-living cells and biofilm of P. aeruginosa were studied using the chequerboard method and time-kill assays. The ability of AgNPs to induce a stress response was determined by evaluation of cellular levels of the DnaK and HtpG chaperones using SDS-PAGE and Western blot analysis. Synergistic activity against free-living P. aeruginosa between AgNPs and ampicillin, streptomycin, rifampicin and tetracycline, but not oxacillin, ciprofloxacin, meropenem or ceftazidime, was demonstrated by the chequerboard method. No such interactions were observed against P. aeruginosa biofilm. The results of time-kill assays confirmed synergy only for the AgNPs-streptomycin combination. AgNPs induced the expression of chaperone DnaK. No induction of the HtpG chaperone was detected. In conclusion, AgNPs not only display potent bactericidal activity against P. aeruginosa, but also act synergistically with several conventional antibiotics to enhance their effect against free-living bacteria as determined by the chequerboard method. The time-kill assay proved synergy between AgNPs and streptomycin only. The ability of AgNPs to induce the major chaperone protein DnaK may influence bacterial resistance to antimicrobials.
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http://dx.doi.org/10.1099/jmm.0.068833-0 | DOI Listing |
Trends Endocrinol Metab
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University of Cologne, Faculty of Medicine and University Hospital Cologne, Institute for Metabolomics in Ageing, Cluster of Excellence Cellular Stress Responses in Ageing-associated Diseases (CECAD), Cologne, Germany; University of Cologne, Faculty of Mathematics and Natural Sciences, Institute of Genetics, Cluster of Excellence Cellular Stress Responses in Ageing-associated Diseases (CECAD), Cologne, Germany. Electronic address:
J Dermatol Sci
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Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan; Department of Frontier Science and Interdisciplinary Research, Faculty of Medicine, Kanazawa University, Ishikawa, Japan. Electronic address:
Background: Melanocytes protect the body from ultraviolet radiation by synthesizing melanin. Tyrosinase, a key enzyme in melanin production, accumulates in the endoplasmic reticulum (ER) during melanin synthesis, potentially causing ER stress. However, regulating ER function for melanin synthesis has been less studied than controlling Tyrosinase activity.
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Hunan Key Laboratory for Breeding of Clonally Propagated Forest Trees, Hunan Academy of Forestry, Changsha, Hunan 410004, China. Electronic address:
B-box proteins (BBX) play pivotal roles in the regulation of numerous growth and developmental processes in plants, particularly the light-mediated biosynthesis of pigments. To elucidate the role of BBX transcription factors in the anthocyanin biosynthetic pathway of Lagerstroemia indica leaves, this study identified 41 BBX genes in the L. indica genome.
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Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA; Department of Medicine, VA Medical Center, St. Louis, MO, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA. Electronic address:
Targeting optimal glycemic control based on hemoglobin A1c (A1c) values reduces but does not abolish the onset of diabetic kidney disease and its progression to chronic kidney disease (CKD). This suggests that factors other than the average glucose contribute to the residual risk. Vitamin D deficiency and frequent episodes of acute hyperglycemia (AH) are associated with the onset of albuminuria and CKD progression in diabetes.
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Department of Surgery, Emory University, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; Research Services, Atlanta VA Medical Center, Decatur, GA, USA. Electronic address:
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