Photoselective discrimination of matrix isolated respiratory enzymes from E. coli by Fourier transform infrared spectroscopy

1992 ◽  
Author(s):  
John J. Hill ◽  
R. B. Gennis ◽  
James O. Alben
2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Simona-Liliana Iconaru ◽  
Mikael Motelica-Heino ◽  
Daniela Predoi

Fourier transform infrared spectroscopy (FT-IR) analysis was conducted on europium-doped hydroxyapatite,Ca10-xEux(PO4)6(OH)2nanocrystalline powders (Eu:HAp) with0≤xEu≤0.2. Antimicrobial studies were also performed for the first time on Eu:HAp. The antimicrobial properties of Eu:HAp nanoparticles with0≤xEu≤0.2on Gram-negative (E. coli ATCC 25922,Pseudomonas aeruginosa 1397) and Gram-positive (Staphylococcus aureus 0364,Enterococcus faecalis ATCC 29212) bacteria systems and a species of fungus (Candida albicans ATCC 10231) were reported. Our study demonstrates that the antimicrobial activity of Eu:HAp nanoparticles is dependent on the europium concentration.


Author(s):  
B Aksakal ◽  
M Demirel

Selenium (Se)- and Silver (Ag)-doped Bioglass®-based biografts were synthesized using the sol–gel method. Fourier-transform infrared spectroscopy, inductively coupled plasma mass spectrometry, scanning electron microscopy and energy-dispersive X-ray analyses were carried out in order to examine mechanostructure of synthesized bioglass-based bioceramics. The effects of Se and Ag additions on cell viability were investigated via cytotoxicity and antibacterial activity analysis, respectively. The bacteria of Escherichia coli ( E. coli, JM103) and Gram-positive Staphylococcus aureus ( S. aureus, ATCC29293) were used to perform the antibacterial tests. Moreover, cell viability studies were conducted using the Saos-2 osteoblast cells by performing dimethylthiazol diphenyltetrazolium bromide assay. It was observed that while (PO4)3− and (CO3)2− peaks were observed in Fourier-transform infrared spectroscopy analyses, crystallinity also increased with increasing amount of AgNO3 addition into the Bioglass®. In addition, it was determined from scanning electron microscopy images that small irregular thin lamellar grain distribution was formed in synthesized B45Ag5Se20 and B30Ag10Se15 biografts. From antibacterial activity tests, it was determined that while some grafts was affected by E. coli, which is a Gram-negative, however, some did not affect the Gram-positive S. aureus and had antimicrobial activity on E. coli and S. aureus. According to the cell viability tests, it was found that the synthesized grafts did not have toxic effect on living cells. While the cell growth was greater for some grafts, however, some others had lower growth.


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