| Summary: | 博士 === 國立臺灣大學 === 農業化學系 === 84 === In this study, the rapid and accurate method was established
for the identificatioin and detection of yeasts in contaminated
foods. Specific identification of yeasts was achieved with DNA
hybridization by immobilizing PCR-amplified ribosomal DNA
(rDNA) internal transcribed spacer (ITS) on the piezoelectric
quartz crystal. In contrast, the conventional methods which
utilize morphological, physiological and biochemical tests for
identifi- cation are time-consuming, while the present method
took only two days. In this study, the CO2-producing yeasts
from gas forming soy sauce and beverage cans were isolated,
identified by conventional methods and their growth inhibition
were studied. On the other hand, two sets of universal primers
were used to amplify ITSI and ITSII of rDNA by polymerase chain
reaction (PCR), and the fragments of ITS were used to differen-
tiate and identify the contaminating yeasts. Alignment of
ribosomal ITS sequence of pathogenic Candida albicans SY-5 with
other species, two set of specific primers were used to detect
Candida albicans by PCR. The PCR products-ITSCA1 (87 bp) and
ITSCA2 (110 bp) were confirmed by Southern blotting and reveal-
ed with digoxigenin labeled ANAB1 and ANAB2 probes. In a PZ-
DNA probe system, the target DNA is hybridized in solution to a
DNA probe that has been covalently immobilized on a PZ crystal
electrode. The PZ-DNA probe measuring system has a potential
to provide a convenient, real time, automatic, low- cost and
high-sensitivity detection method. The PZ identifi- cation
system can be used for Hazard Analysis Critical Control Point
(HACCP) in food industry and for the analysis of yeasts in the
contaminated products.
|
|---|
