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  • 标题:A tryptophan synchronous and normal fluorescence study on bacteria inactivation mechanism
  • 本地全文:下载
  • 作者:Runze Li ; Runze Li ; Dinesh Dhankhar
  • 期刊名称:Proceedings of the National Academy of Sciences
  • 印刷版ISSN:0027-8424
  • 电子版ISSN:1091-6490
  • 出版年度:2019
  • 卷号:116
  • 期号:38
  • 页码:18822-18826
  • DOI:10.1073/pnas.1909722116
  • 出版社:The National Academy of Sciences of the United States of America
  • 摘要:The UV photodissociation kinetics of tryptophan amino acid, Trp, attached to the membrane of bacteria, Escherichia coli and Bacillus subtilis , have been studied by means of normal and synchronous fluorescence. Our experimental data suggest that the fluorescence intensity of Trp increases during the first minute of irradiation with 250 nm to ∼ 280 nm, 7 mW/cm 2 UV light, and subsequently decreases with continuous irradiation. During this short, less than a minute, period of time, 70% of the 10 7 cell per milliliter bacteria are inactivated. This increase in fluorescence intensity is not observed when tryptophan is in the free state, namely, not attached to a protein, but dissolved in water or saline solution. This increase in fluorescence is attributed to the additional fluorescence of tryptophan molecules formed by protein unfolding, the breakage of the bond that attaches Trp to the bacterial protein membrane, or possibly caused by the irradiation of 2 types of tryptophan residues that photolyze with different quantum yields..
  • 关键词:bacteria inactivation ; synchronous fluorescence ; photodissociation kinetics
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