克雷白氏肺炎桿菌 DNA adenine methylase (Dam) 與致病力相關性的研究(1/2)
Date Issued
2003
Date
2003
Author(s)
方啟泰
DOI
912314B002178
Abstract
Klebsiella pneumoniae, an enteric Gram-negative bacillus, is one of the most
important human pathogen in Taiwan. K. pneumoniae causes life-threatening
pyogenic liver abscess, bacteremia, septic endophthalmitis and meningitis in both
diabetic persons and otherwise healthy people. K. pneumoniae is also an important
pathogen of nosocomial pneumonia and urinary tract infection. The regulation of
virulence gene expression in K. pneumoniae has been poorly understood. DNA
adenine methylase (Dam) can add methyl group to the adenine of sequence GATC,
and thus play an important role in the control of bacterial gene expression. In
Salmonella, another enteric Gram- negative bacillus, the role of Dam in the
regulation of virulence has been well documented. dam - Salmonella mutants
significantly loss the virulence potential. The role of Dam in K. pneumoniae has not
yet been studied. The purpose of this proposal is to investigate the relationship
between Dam and bacterial virulence in K. pneumoniae. We have successfully
cloned the dam gene in K. pneumoniae. We used the nucleotides sequence of dam
gene in E. coli K12, available on NCBI website, to design PCR primers. Using
designed primers, we successfully amplify a DNA fragment containing a 669 bps
open reading frame from the genomic DNA of clinical invasive strain K.
pneumoniae NTUH-2044. We further constructed dam - mutant by inserting
chloramphenicol acetyltransferase (CAT) cassette into dam and sending the mutated
dam into wild type NTUH-2044 for homologous recombination. Four dam - K.
pneumoniae mutants were obtained, and all of them had much reduced serum
resistance in comparison with the wild type. In the second year, animal study will be
used to determine the difference in LD50 to quantify the correlation between Dam
and bacterial virulence in K. pneumoniae. Microarray technique will be used to
identify the downstream genes regulated by dam. Finally, the possibility of dam - K.
pneumoniae mutants as vaccine strains will be explored through animal experiments.
Subjects
Klebsiella pneumoniae
virulence
DNA adenine methylase
SDGs
Publisher
臺北市：國立臺灣大學醫學院內科
Type
report
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