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Identification of the genetic determinants of Salmonella enterica serotype Typhimurium that may regulate the expression of the type 1 fimbriae in response to solid agar and static broth culture conditions.

Chuang YC, Wang KC, Chen YT, Yang CH, Men SC, Fan CC, Chang LH, Yeh KS - BMC Microbiol. (2008)

Bottom Line: Type 1 fimbriae are the most commonly found fimbrial appendages on the outer membrane of Salmonella enterica serotype Typhimurium.Typhimurium is the result of the interaction and cooperation of several genes in the fim gene cluster.Typhimurium.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Research, Chi Mei Medical Center, 901 Chung Hwa Road, Yong Kang City, Tainan 710, Taiwan. chuangkenneth@hotmail.com

ABSTRACT

Background: Type 1 fimbriae are the most commonly found fimbrial appendages on the outer membrane of Salmonella enterica serotype Typhimurium. Previous investigations indicate that static broth culture favours S. Typhimurium to produce type 1 fimbriae, while non-fimbriate bacteria are obtained by growth on solid agar media. The phenotypic expression of type 1 fimbriae in S. Typhimurium is the result of the interaction and cooperation of several genes in the fim gene cluster. Other gene products that may also participate in the regulation of type 1 fimbrial expression remain uncharacterized.

Results: In the present study, transposon insertion mutagenesis was performed on S. Typhimurium to generate a library to screen for those mutants that would exhibit different type 1 fimbrial phenotypes than the parental strain. Eight-two mutants were obtained from 7,239 clones screened using the yeast agglutination test. Forty-four mutants produced type 1 fimbriae on both solid agar and static broth media, while none of the other 38 mutants formed type 1 fimbriae in either culture condition. The flanking sequences of the transposons from 54 mutants were cloned and sequenced. These mutants can be classified according to the functions or putative functions of the open reading frames disrupted by the transposon. Our current results indicate that the genetic determinants such as those involved in the fimbrial biogenesis and regulation, global regulators, transporter proteins, prophage-derived proteins, and enzymes of different functions, to name a few, may play a role in the regulation of type 1 fimbrial expression in response to solid agar and static broth culture conditions. A complementation test revealed that transforming a recombinant plasmid possessing the coding sequence of a NAD(P)H-flavin reductase gene ubiB restored an ubiB mutant to exhibit the type 1 fimbrial phenotype as its parental strain.

Conclusion: Genetic determinants other than the fim genes may involve in the regulation of type 1 fimbrial expression in S. Typhimurium. How each gene product may influence type 1 fimbrial expression is an interesting research topic which warrants further investigation.

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Related in: MedlinePlus

RT-PCR for fimA transcription. RT-PCR assays were used to monitor fimA and 16S rRNA transcription in the parental strain LB5010, ubiB mutant, and ubiB (pUbiB) strain. The intensities of the bands for each strain were determined by densitometry and expressed (Arabic numbers) relative to the value for fimA transcription obtained from the static LB broth culture condition. The intensities of 16S rRNA shown indicates that equivalent amounts of total RNA were used in the experiment.
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Figure 3: RT-PCR for fimA transcription. RT-PCR assays were used to monitor fimA and 16S rRNA transcription in the parental strain LB5010, ubiB mutant, and ubiB (pUbiB) strain. The intensities of the bands for each strain were determined by densitometry and expressed (Arabic numbers) relative to the value for fimA transcription obtained from the static LB broth culture condition. The intensities of 16S rRNA shown indicates that equivalent amounts of total RNA were used in the experiment.

Mentions: Total RNA from the parental strain S. Typhimurium LB5010, K48 ubiB mutant, and K48 ubiB (pUbiB) were prepared and analyzed for fimA mRNA and 16S rRNA expression by RT-PCR. Figure 3 showed the RT-PCR analysis results. As for the parental strain LB5010, the fimA expression obtained from the static broth was approximately 4.5 fold (1: 0.22) of that obtained from the agar culture condition. For the K48 ubiB mutant, expression of fimA (static broth) was about 60% (1: 1.74) of the fimA (agar). When K48 ubiB strain harboured the plasmid pUbiB, fimA expression (broth) was about 2.6 fold (1: 0.39) of fimA (agar). As a control, 16S rRNA was constantly expressed in all the strains tested.


Identification of the genetic determinants of Salmonella enterica serotype Typhimurium that may regulate the expression of the type 1 fimbriae in response to solid agar and static broth culture conditions.

Chuang YC, Wang KC, Chen YT, Yang CH, Men SC, Fan CC, Chang LH, Yeh KS - BMC Microbiol. (2008)

RT-PCR for fimA transcription. RT-PCR assays were used to monitor fimA and 16S rRNA transcription in the parental strain LB5010, ubiB mutant, and ubiB (pUbiB) strain. The intensities of the bands for each strain were determined by densitometry and expressed (Arabic numbers) relative to the value for fimA transcription obtained from the static LB broth culture condition. The intensities of 16S rRNA shown indicates that equivalent amounts of total RNA were used in the experiment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2527010&req=5

Figure 3: RT-PCR for fimA transcription. RT-PCR assays were used to monitor fimA and 16S rRNA transcription in the parental strain LB5010, ubiB mutant, and ubiB (pUbiB) strain. The intensities of the bands for each strain were determined by densitometry and expressed (Arabic numbers) relative to the value for fimA transcription obtained from the static LB broth culture condition. The intensities of 16S rRNA shown indicates that equivalent amounts of total RNA were used in the experiment.
Mentions: Total RNA from the parental strain S. Typhimurium LB5010, K48 ubiB mutant, and K48 ubiB (pUbiB) were prepared and analyzed for fimA mRNA and 16S rRNA expression by RT-PCR. Figure 3 showed the RT-PCR analysis results. As for the parental strain LB5010, the fimA expression obtained from the static broth was approximately 4.5 fold (1: 0.22) of that obtained from the agar culture condition. For the K48 ubiB mutant, expression of fimA (static broth) was about 60% (1: 1.74) of the fimA (agar). When K48 ubiB strain harboured the plasmid pUbiB, fimA expression (broth) was about 2.6 fold (1: 0.39) of fimA (agar). As a control, 16S rRNA was constantly expressed in all the strains tested.

Bottom Line: Type 1 fimbriae are the most commonly found fimbrial appendages on the outer membrane of Salmonella enterica serotype Typhimurium.Typhimurium is the result of the interaction and cooperation of several genes in the fim gene cluster.Typhimurium.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medical Research, Chi Mei Medical Center, 901 Chung Hwa Road, Yong Kang City, Tainan 710, Taiwan. chuangkenneth@hotmail.com

ABSTRACT

Background: Type 1 fimbriae are the most commonly found fimbrial appendages on the outer membrane of Salmonella enterica serotype Typhimurium. Previous investigations indicate that static broth culture favours S. Typhimurium to produce type 1 fimbriae, while non-fimbriate bacteria are obtained by growth on solid agar media. The phenotypic expression of type 1 fimbriae in S. Typhimurium is the result of the interaction and cooperation of several genes in the fim gene cluster. Other gene products that may also participate in the regulation of type 1 fimbrial expression remain uncharacterized.

Results: In the present study, transposon insertion mutagenesis was performed on S. Typhimurium to generate a library to screen for those mutants that would exhibit different type 1 fimbrial phenotypes than the parental strain. Eight-two mutants were obtained from 7,239 clones screened using the yeast agglutination test. Forty-four mutants produced type 1 fimbriae on both solid agar and static broth media, while none of the other 38 mutants formed type 1 fimbriae in either culture condition. The flanking sequences of the transposons from 54 mutants were cloned and sequenced. These mutants can be classified according to the functions or putative functions of the open reading frames disrupted by the transposon. Our current results indicate that the genetic determinants such as those involved in the fimbrial biogenesis and regulation, global regulators, transporter proteins, prophage-derived proteins, and enzymes of different functions, to name a few, may play a role in the regulation of type 1 fimbrial expression in response to solid agar and static broth culture conditions. A complementation test revealed that transforming a recombinant plasmid possessing the coding sequence of a NAD(P)H-flavin reductase gene ubiB restored an ubiB mutant to exhibit the type 1 fimbrial phenotype as its parental strain.

Conclusion: Genetic determinants other than the fim genes may involve in the regulation of type 1 fimbrial expression in S. Typhimurium. How each gene product may influence type 1 fimbrial expression is an interesting research topic which warrants further investigation.

Show MeSH
Related in: MedlinePlus