scholarly journals Regulation of the Klebsiella pneumoniae Kpc fimbriae by the site-specific recombinase KpcI

Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 1983-1992 ◽  
Author(s):  
Chien-Chen Wu ◽  
Ying-Jung Huang ◽  
Chang-Phone Fung ◽  
Hwei-Ling Peng
Keyword(s):  
Klebsiella Pneumoniae ◽  
Gene Clusters ◽  
Upstream Region ◽  
Phase Variable ◽  
Induced Expression ◽  
Site Specific ◽  
Putative Site ◽  
In Trans ◽  
Type 3

In the genome of Klebsiella pneumoniae NTUH-K2044, nine fimbrial gene clusters were identified. Besides type 1 and type 3 fimbriae, the others are novel and were named Kpa, Kpb, Kpc, Kpd, Kpe, Kpf and Kpg fimbriae. Prevalence analysis among 105 K. pneumoniae clinical isolates revealed that the kpc genes were highly associated with the K1 serotype isolates. Induced expression of the recombinant kpcABCD genes in Escherichia coli resulted in Kpc fimbriation and increased biofilm formation. A putative site-specific recombinase encoding gene kpcI and a 302 bp intergenic DNA flanked by 11 bp inverted repeats, namely kpcS, were identified in the upstream region of the kpcABCD genes. Using LacZ as the reporter, a dramatic difference in promoter activity of kpcS in two different orientations was observed and accordingly assigned as ON and OFF phase. kpcI expression was found to be able to invert kpcS in trans from phase ON to OFF and vice versa. Using the two-plasmid system, expression of kpcA, encoding the major component of the Kpc fimbriae, could be observed upon the induced expression of kpcI. These results indicate that KpcI is involved in the regulation of Kpc fimbriation in a phase-variable manner.

scholarly journals Variable Lipoprotein Genes of Mycoplasma agalactiae Are Activated In Vivo by Promoter Addition via Site-Specific DNA Inversions

2003 ◽  
Vol 71 (7) ◽  
pp. 3821-3830 ◽  
Author(s):  
Ravenna Flitman-Tene ◽  
Sigalit Mudahi-Orenstein ◽  
Sharon Levisohn ◽  
David Yogev
Keyword(s):  
Dna Recombination ◽  
Small Ruminants ◽  
Upstream Region ◽  
Pcr Analysis ◽  
Phase Variable ◽  
Multiple Sequence ◽  
Site Specific ◽  
Mycoplasma Agalactiae ◽  
Variable Expression

ABSTRACT Mycoplasma agalactiae, the etiological agent of contagious agalactia of small ruminants, has a family of related genes (avg genes) which encode surface lipoprotein antigens that undergo phase variation. A series of 13 M. agalactiae clonal isolates, obtained from one chronically infected animal over a period of 7 months, were found to undergo major rearrangement events within the avg genomic locus. We show that these rearrangements regulate the phase-variable expression of individual avg genes. Northern blot analysis and reverse transcription-PCR showed that only one avg gene is transcribed, while the other avg genes are transcriptionally silent. Sequence analysis and primer extension experiments with two M. agalactiae clonal isolates showed that a specific 182-bp avg 5′ upstream region (avg-B2) that is present as a single chromosomal copy serves as an active promoter and exhibits a high level of homology with the vsp promoter of the bovine pathogen Mycoplasma bovis. PCR analysis showed that each avg gene is associated with the avg-B2 promoter in a subpopulation of cells that is present in each subclone. Multiple sequence-specific sites for DNA recombination (vis-like), which are presumably recognized by site-specific recombinase, were identified within the conserved avg 5′ upstream regions of all avg genes and were found to be identical to the recombination sites of the M. bovis vsp locus. In addition, a gene encoding a member of the integrase family of tyrosine site-specific recombinases was identified adjacent to the variable avg locus. The molecular genetic basis for avg phase-variable expression appears to be mediated by site-specific DNA inversions occurring in vivo that allow activation of a silent avg gene by promoter addition. A model for the control of avg genes is proposed.

scholarly journals Role of type 1 and type 3 fimbriae in Klebsiella pneumoniae biofilm formation

2010 ◽  
Vol 10 (1) ◽  
pp. 179 ◽  
Author(s):  
Casper Schroll ◽  
Kim B Barken ◽  
Karen A Krogfelt ◽  
Carsten Struve
Keyword(s):  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Type 3

scholarly journals Genome Analysis Suggests The Bacterial Family Acetobacteraceae is a Source of Undiscovered Specialized Metabolites

2021 ◽  
Author(s):  
Juan David Guzman ◽  
Andreas Vilcinskas
Keyword(s):  
Hot Springs ◽  
Gene Clusters ◽  
Acetic Acid Bacteria ◽  
Specialized Metabolites ◽  
The Family ◽  
Genes Encoding ◽  
Peptide Biosynthesis ◽  
Taxonomic Groups ◽  
Type 3

Abstract Acetobacteraceae is an economically important family of bacteria that is used for industrial fermentation in the food/feed sector and for the preparation of sorbose and bacterial cellulose. It comprises two major groups: acetous species (acetic acid bacteria) associated with flowers, fruits and insects, and acidophilic species, a phylogenetically basal and physiologically heterogeneous group inhabiting acid or hot springs, sludge, sewage and freshwater environments. Despite the biotechnological importance of the family Acetobacteraceae, the literature does not provide any information about its ability to produce specialized metabolites. We therefore constructed a phylogenomic tree based on concatenated protein sequences from 127 type strains of the family and predicted the presence of small-molecule biosynthetic gene clusters (BGCs) using the antiSMASH tool. This dual approach allowed us to associate certain biosynthetic pathways with particular taxonomic groups. We found that acidophilic and acetous species contain on average ~6 and ~3.4 BGCs per genome, respectively. All the Acetobacteraceae strains encoded proteins associated involved in hopanoid biosynthesis, with many also featuring genes encoding type-1 and type-3 polyketide and non-ribosomal peptide synthases, and enzymes for aryl polyene, lactone and ribosomal peptide biosynthesis. Our in silico analysis indicated that the family Acetobacteraceae is a potential source of many undiscovered bacterial metabolites and deserves more detailed experimental exploration.

scholarly journals Characterization of the regulatory regions in the human desmoglein genes encoding the pemphigus foliaceous and pemphigus vulgaris antigens

1998 ◽  
Vol 329 (1) ◽  
pp. 165-174 ◽  
Author(s):  
J. Michael ADAMS ◽  
B. Martin REICHEL ◽  
A. Ian KING ◽  
D. Mark MARSDEN ◽  
D. Matthew GREENWOOD ◽  
...  
Keyword(s):  
Transcription Initiation ◽  
Pemphigus Vulgaris ◽  
Upstream Region ◽  
Lacz Gene ◽  
Start Site ◽  
Translation Start Site ◽  
Translation Start ◽  
Adhesive Proteins ◽  
Type 3

The adhesive proteins in the desmosome type of cell junction consist of two members of the cadherin superfamily, the desmogleins and desmocollins. Both desmogleins and desmocollins occur as at least three different isoforms with various patterns of expression. The molecular mechanisms controlling the differential expression of the desmosomal cadherin isoforms are not yet known. We have begun an investigation of desmoglein gene expression by cloning and analysing the promoters of the human genes coding for the type 1 and type 3 desmogleins (DSG1 and DSG3). The type 1 isoform is restricted to the suprabasal layers of the epidermis and is the autoantigen in the autoimmune blistering skin disease pemphigus foliaceous. The type 3 desmoglein isoform is also expressed in the epidermis, but in lower layers than the type 1 isoform, and is the autoantigen in pemphigus vulgaris. Phage ƛ genomic clones were obtained containing 4.2 kb upstream of the translation start site of DSG1 and 517 bp upstream of the DSG3 start site. Sequencing of 660 bp upstream of DSG1 and 517 bp upstream of DSG3 revealed that there was no obvious TATA box, but a possible CAAT box was present at -238 in DSG1 and at -193 in DSG3 relative to the translation start site. Primer extension analysis and RNase protection experiments revealed four putative transcription initiation sites for DSG1 at positions -163, -151, -148 and -141, and seven closely linked sites for DSG3, the longest being at -140 relative to the translation start site. The sequences at these possible sites at -166 to -159 in DSG1 (TTCAGTCC) and at -124 to -117 in DSG3 (CTTAGACT) have some similarity to the initiator sequence (CTCANTCT) described for a TATA-less promoter often from -3 to +5, and the true transcription initiator site might therefore be the A residue in these sequences. There were two regions of similarity between the DSG1 and DSG3 promoters just upstream of the transcription initiation sites, of 20 and 13 bp, separated by 41 bp in DSG1 and 36 bp in DSG3. The significance of these regions of similarity remains to be elucidated, but the results suggest that they represent a point at which these two desmoglein genes are co-ordinately regulated. Analysis of the upstream sequences revealed GC-rich regions and consensus binding sites for transcription factors including AP-1 and AP-2. Exon boundaries were conserved compared with the classical cadherin E-cadherin, but the equivalent of the second cadherin intron was lacking. A 4.2 kb region of the human DSG1 promoter sequence was linked to the lacZ gene reporter gene in such a way that there was only one translation start site, and this construct was used to generate transgenic mice. We present the first transgenic analysis of a promoter region taken from a desmosomal cadherin gene. Our results suggest that the 4.2 kb upstream region of DSG1 does not contain all the regulatory elements necessary for correct expression of this gene but might have elements that regulate activity during hair growth.

scholarly journals HbiF Regulates Type 1 Fimbriation Independently of FimB and FimE

2006 ◽  
Vol 74 (7) ◽  
pp. 4039-4047 ◽  
Author(s):  
Yi Xie ◽  
Yufeng Yao ◽  
Vitaliy Kolisnychenko ◽  
Ching-Hao Teng ◽  
Kwang Sik Kim
Keyword(s):  
Infection Type ◽  
Constitutive Expression ◽  
Phase Variable ◽  
Neonatal Rats ◽  
Site Specific ◽  
E Coli ◽  
And Control ◽  
High Degree ◽  
Prevention And Therapy

ABSTRACT Type 1 fimbriae have been suggested to play a role in the pathogenesis of extraintestinal Escherichia coli infection. Type 1 fimbriation in E. coli is phase variable and known to be dependent upon FimB and FimE, the two recombinases that invert the molecular switch fimS and control the expression of the downstream fim operon. Here we showed that HbiF, a novel site-specific recombinase, inverted fimS independently of FimB and FimE. HbiF-mediated fimS inversion appeared to be predominantly switching from “off” (termed OFF) to “on” (termed ON) orientation. This is different from the fimS inversion mediated by either FimB (bidirectional ON to OFF and OFF to ON) or FimE (unidirectional ON to OFF). Constitutive expression of the hbiF gene in E. coli resulted in a fimS-locked-ON phenotype, which resulted in the pathogenic E. coli K1 strain being incapable of inducing a high degree of bacteremia in neonatal rats. Discovery of HbiF-mediated OFF-to-ON fimS switching provides a new opportunity to develop a strategy for the prevention and therapy of extraintestinal E. coli infection including bacteremia and meningitis.

scholarly journals High Levels of Cyclic Di-GMP in Klebsiella pneumoniae Attenuate Virulence in the Lung

2017 ◽  
Vol 86 (2) ◽  
Author(s):  
David A. Rosen ◽  
Joy Twentyman ◽  
David A. Hunstad
Keyword(s):  
Klebsiella Pneumoniae ◽  
Pathogenic Bacteria ◽  
Host Responses ◽  
Potential Therapeutic Target ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Bacterial Physiology ◽  
Type 1 Pili ◽  
Type 3

ABSTRACTThe bacterial second messenger bis-(3′-5′)-cyclic dimeric GMP (c-di-GMP) has been shown to influence the expression of virulence factors in certain pathogenic bacteria, but little is known about its activity in the increasingly antibiotic-resistant pathogenKlebsiella pneumoniae. Here, the expression inK. pneumoniaeof a heterologous diguanylate cyclase increased the bacterial c-di-GMP concentration and attenuated pathogenesis in murine pneumonia. This attenuation remained evident in mice lacking the c-di-GMP sensor STING, indicating that the high c-di-GMP concentration exerted its influence not on host responses but on bacterial physiology. While serum resistance and capsule expression were unaffected by the increased c-di-GMP concentration, both type 3 and type 1 pili were strongly upregulated. Importantly, attenuation ofK. pneumoniaevirulence by high c-di-GMP levels was abrogated when type 1 pilus expression was silenced. We conclude that increased type 1 piliation may hamperK. pneumoniaevirulence in the respiratory tract and that c-di-GMP signaling represents a potential therapeutic target for antibiotic-resistantK. pneumoniaein this niche.

scholarly journals Identification of a Conserved Chromosomal Region Encoding Klebsiella pneumoniae Type 1 and Type 3 Fimbriae and Assessment of the Role of Fimbriae in Pathogenicity

2009 ◽  
Vol 77 (11) ◽  
pp. 5016-5024 ◽  
Author(s):  
Carsten Struve ◽  
Martin Bojer ◽  
Karen Angeliki Krogfelt
Keyword(s):  
Klebsiella Pneumoniae ◽  
Gene Cluster ◽  
Virulence Factor ◽  
Biofilm Formation ◽  
Regulatory Gene ◽  
Infection Model ◽  
Type 3

ABSTRACT Type 3 fimbriae are expressed by most clinical Klebsiella pneumoniae isolates and mediate adhesion to host structures in vitro. However, the role of type 3 fimbriae in K. pneumoniae virulence has not been evaluated by use of in vivo infection models. In this study, the type 3 fimbrial gene cluster (mrk) of the clinical isolate C3091 is described in detail. The mrk gene cluster was revealed to be localized in close proximity to the type 1 fimbrial gene cluster. Thus, a 20.4-kb fimbria-encoding region was identified and found to be highly conserved among different K. pneumoniae isolates. Interestingly, a homologue to PecS, known as a global regulator of virulence in Erwinia chrysanthemi, was identified in the fimbria-encoding region. Comparison to the previously characterized plasmid encoded mrk gene cluster revealed significant differences, and it is established here that the putative regulatory gene mrkE is not a part of the chromosomally encoded type 3 fimbrial gene cluster. To evaluate the role of type 3 fimbriae in virulence, a type 3 fimbria mutant and a type 1 and type 3 fimbria double mutant was constructed. Type 3 fimbria expression was found to strongly promote biofilm formation. However, the fimbria mutants were as effective at colonizing the intestine as the wild type, and their virulence was not attenuated in a lung infection model. Also, in a urinary tract infection model, type 3 fimbriae did not influence the virulence, whereas type 1 fimbriae were verified as an essential virulence factor. Thus, type 3 fimbriae were established not to be a virulence factor in uncomplicated K. pneumoniae infections. However, since type 3 fimbriae promote biofilm formation, their role in development of infections in catheterized patients needs to be elucidated.

scholarly journals Role of Klebsiella pneumoniae Type 1 and Type 3 Fimbriae in Colonizing Silicone Tubes Implanted into the Bladders of Mice as a Model of Catheter-Associated Urinary Tract Infections

2013 ◽  
Vol 81 (8) ◽  
pp. 3009-3017 ◽  
Author(s):  
Caitlin N. Murphy ◽  
Martin S. Mortensen ◽  
Karen A. Krogfelt ◽  
Steven Clegg
Keyword(s):  
Urinary Tract ◽  
Klebsiella Pneumoniae ◽  
Urinary Tract Infections ◽  
Wild Type ◽  
Content Type ◽  
Tract Infections ◽  
Type 3

ABSTRACTCatheter-associated urinary tract infections are biofilm-mediated infections that cause a significant economic and health burden in nosocomial environments. Using a newly developed murine model of this type of infection, we investigated the role of fimbriae in implant-associated urinary tract infections by the Gram-negative bacteriumKlebsiella pneumoniae, which is a proficient biofilm former and a commonly isolated nosocomial pathogen. Studies have shown that type 1 and type 3 fimbriae are involved in attachment and biofilm formationin vitro, and these fimbrial types are suspected to be important virulence factors during infection. To test this hypothesis, the virulence of fimbrial mutants was assessed in independent challenges in which mouse bladders were inoculated with the wild type or a fimbrial mutant and in coinfection studies in which the wild type and fimbrial mutants were inoculated together to assess the results of a direct competition in the urinary tract. Using these experiments, we were able to show that both fimbrial types serve to enhance colonization and persistence. Additionally, a double mutant had an additive colonization defect under some conditions, indicating that both fimbrial types have unique roles in the attachment and persistence in the bladder and on the implant itself. All of these mutants were outcompeted by the wild type in coinfection experiments. Using these methods, we are able to show that type 1 and type 3 fimbriae are important colonization factors in the murine urinary tract when an implanted silicone tube is present.

scholarly journals Coordinate Expression of Fimbriae in Uropathogenic Escherichia coli

2005 ◽  
Vol 73 (11) ◽  
pp. 7588-7596 ◽  
Author(s):  
Jennifer A. Snyder ◽  
Brian J. Haugen ◽  
C. Virginia Lockatell ◽  
Nathalie Maroncle ◽  
Erin C. Hagan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Gene Clusters ◽  
Phase Variable ◽  
Type 1 Fimbriae ◽  
Coordinated Expression ◽  
Tract Infections

ABSTRACT Uropathogenic Escherichia coli is the most common etiological agent of urinary tract infections. Bacteria can often express multiple adhesins during infection in order to favor attachment to specific niches within the urinary tract. We have recently demonstrated that type 1 fimbria, a phase-variable virulence factor involved in adherence, was the most highly expressed adhesin during urinary tract infection. Here, we examine whether the expression of type 1 fimbriae can affect the expression of other adhesins. Type 1 fimbrial phase-locked mutants of E. coli strain CFT073, which harbors genes for numerous adhesins, were employed in this study. CFT073-specific DNA microarray analysis of these strains demonstrates that the expression of type 1 fimbriae coordinately affects the expression of P fimbriae in an inverse manner. This represents evidence for direct communication between genes relating to pathogenesis, perhaps to aid the sequential occupation of different urinary tract tissues. While the role of type 1 fimbriae during infection has been clear, the role of P fimbriae must be further defined to assert the relevance of coordinated regulation in vivo. Therefore, we examined the ability of P fimbrial isogenic mutants, constructed in a type 1 fimbrial-negative background, to compete in the murine urinary tract over a period of 168 h. No differences in the colonization of these mutants were observed. However, comparison of these results with previous studies suggests that inversely coordinated expression of adhesin gene clusters does occur in vivo. Interestingly, the mutant that was incapable of expressing either type 1 or P fimbriae compensated by synthesizing F1C fimbriae.

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