碩士 / 國立臺灣大學 / 微生物與生化學研究所 / 93 / Photodynamic inactivation (PDI) utilized photosensitizers and light
with appropriate wave length to give a phototoxic response, normally via
oxidative damage. Although PDI might be an effective approach in
antimicrobial treatment, no photosensitizer is suitable for all possible
applications. Therefore, the development of new photosensitizers became
important to overcome the shortage of PDI. Phycocyanin (PC), a
water-soluble non-toxic biliprotein, is one of the major constituents of
Spirulina platensis. The photobiological properties of PC suggested its
possibility to be a photosensitizer in photodynamic therapy. The goal of
this study was to investigate the effect of the PC extracted from Sp.
platensis on photodynamic inactivation against bacterial planktonic and
biofilm cells. The extraction and purification of PC was accomplished by
fractional precipitation with ammonium sulfate precipitation, following
by ion-exchange chromagraphy on Macro-Prep DEAE Support system.
The purity of PC was examined by absorbance and fluorescence
spectrometry. Both Gram-positive and Gram-negative bacteria were
tested for PC-PDI. Pure PC was finally obtained from Sp. platensis with
purity ratio (A620nm/280nm) 4.56 and recovery rate 56.1%. After PC-PDI
treatment, which carried with 100 µg ml-1 of PC and irradiation light dose
of 360 J cm-2, no viable cell of the Gram-positive Staphylococcus aureus
and S. epidermis planktonic cells were detected. However, the
Gram-negative Escherichia coli and Pseudomonas aeruginosa were
resistant to the PC-PDI treatment. Experiments with PC-PDI against S.
aureus and S. epidermis biofilms showed that both species of the tested
biofilms were sensitive to the PC-PDI treatment, with a decrease of about
8-log of viable cells. This study showed that the PC from Sp. platensis
was a potential photosensitizer to inactivated Gram-positive bacteria
planktonic cells and biofilms.
Keyword: Photodynamic Inactivation, Spirulina platensis, Phycocyanin,
Biofilm
| Identifer | oai:union.ndltd.org:TW/093NTU05381076 |
| Date | January 2005 |
| Creators | Ya-Ping Tu, 凃雅屏 |
| Contributors | 黃慶璨 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 87 |
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