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Genome analysis of quorum sensing Cedecea neteri SSMD04 leads to identification of its novel signaling synthase (cneI), cognate receptor (cneR) and an orphan receptor.

Tan KH, Tan JY, Yin WF, Chan KG - PeerJ (2015)

Bottom Line: The AHL synthase, which we named cneI(636 bp), was found in the genome sequences of C. neteri SSMD04.Analysis of this protein amino acid sequence reveals two signature domains, the autoinducer-binding domain and the C-terminal effector which is typical characteristic of luxR.In addition, we found that this genome harboured an orphan luxR that is most closely related to easR in Enterobacter asburiae.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia.

ABSTRACT
Cedecea neteri is a very rare human pathogen. We have isolated a strain of C. neteri SSMD04 from pickled mackerel sashimi identified using molecular and phenotypics approaches. Using the biosensor Chromobacterium violaceum CV026, we have demonstrated the presence of short chain N-acyl-homoserine lactone (AHL) type quorum sensing (QS) activity in C. neteri SSMD04. Triple quadrupole LC/MS analysis revealed that C. neteri SSMD04 produced short chain N-butyryl-homoserine lactone (C4-HSL). With the available genome information of C. neteri SSMD04, we went on to analyse and identified a pair of luxI/R homologues in this genome that share the highest similarity with croI/R homologues from Citrobacter rodentium. The AHL synthase, which we named cneI(636 bp), was found in the genome sequences of C. neteri SSMD04. At a distance of 8bp from cneI is a sequence encoding a hypothetical protein, potentially the cognate receptor, a luxR homologue which we named it as cneR. Analysis of this protein amino acid sequence reveals two signature domains, the autoinducer-binding domain and the C-terminal effector which is typical characteristic of luxR. In addition, we found that this genome harboured an orphan luxR that is most closely related to easR in Enterobacter asburiae. To our knowledge, this is the first report on the AHL production activity in C. neteri, and the discovery of its luxI/R homologues, the orphan receptor and its whole genome sequence.

No MeSH data available.


Related in: MedlinePlus

Mass spectrometry analysis of C. neteri SSMD04 spent supernatant extract.Product ions of the peak seen which shows that the extract of C. neteri SSMD04 contains C4-HSL.
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fig-5: Mass spectrometry analysis of C. neteri SSMD04 spent supernatant extract.Product ions of the peak seen which shows that the extract of C. neteri SSMD04 contains C4-HSL.

Mentions: The use of both biosensors (C. violaceum CV026 and E. coli (pSB401)) does not give information on the specific type of AHL produced since each detects a variety of AHLs. Therefore, triple quadrupole LC/MS was employed in the identification of the AHL produced by C. neteri SSMD04. The extracted-ion chromatogram (EIC) generated from the triple quadrupole LC/MS system showed a peak with the same retention time as that of the synthetic N-butyryl-homoserine lactone (C4-HSL) standard, which was constantly present in all three replicates (Fig. 4). Analysis of the mass spectrum (MS) data revealed the presence of a peak with mass-to-charge ratio (m/z) of 172 (Fig. 5), which is consistent with the previously reported value (Ortori et al., 2011). This implication was strengthened by the presence of a product ion peak (m/z = 102), confirming the presence of a homoserine lactone ring, the invariant structure of AHLs. This result is in agreement with the results of the biosensor strains, C. violaceum CV026 and E. coli (pSB401), as both respond to C4-HSL.


Genome analysis of quorum sensing Cedecea neteri SSMD04 leads to identification of its novel signaling synthase (cneI), cognate receptor (cneR) and an orphan receptor.

Tan KH, Tan JY, Yin WF, Chan KG - PeerJ (2015)

Mass spectrometry analysis of C. neteri SSMD04 spent supernatant extract.Product ions of the peak seen which shows that the extract of C. neteri SSMD04 contains C4-HSL.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562240&req=5

fig-5: Mass spectrometry analysis of C. neteri SSMD04 spent supernatant extract.Product ions of the peak seen which shows that the extract of C. neteri SSMD04 contains C4-HSL.
Mentions: The use of both biosensors (C. violaceum CV026 and E. coli (pSB401)) does not give information on the specific type of AHL produced since each detects a variety of AHLs. Therefore, triple quadrupole LC/MS was employed in the identification of the AHL produced by C. neteri SSMD04. The extracted-ion chromatogram (EIC) generated from the triple quadrupole LC/MS system showed a peak with the same retention time as that of the synthetic N-butyryl-homoserine lactone (C4-HSL) standard, which was constantly present in all three replicates (Fig. 4). Analysis of the mass spectrum (MS) data revealed the presence of a peak with mass-to-charge ratio (m/z) of 172 (Fig. 5), which is consistent with the previously reported value (Ortori et al., 2011). This implication was strengthened by the presence of a product ion peak (m/z = 102), confirming the presence of a homoserine lactone ring, the invariant structure of AHLs. This result is in agreement with the results of the biosensor strains, C. violaceum CV026 and E. coli (pSB401), as both respond to C4-HSL.

Bottom Line: The AHL synthase, which we named cneI(636 bp), was found in the genome sequences of C. neteri SSMD04.Analysis of this protein amino acid sequence reveals two signature domains, the autoinducer-binding domain and the C-terminal effector which is typical characteristic of luxR.In addition, we found that this genome harboured an orphan luxR that is most closely related to easR in Enterobacter asburiae.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya , Kuala Lumpur , Malaysia.

ABSTRACT
Cedecea neteri is a very rare human pathogen. We have isolated a strain of C. neteri SSMD04 from pickled mackerel sashimi identified using molecular and phenotypics approaches. Using the biosensor Chromobacterium violaceum CV026, we have demonstrated the presence of short chain N-acyl-homoserine lactone (AHL) type quorum sensing (QS) activity in C. neteri SSMD04. Triple quadrupole LC/MS analysis revealed that C. neteri SSMD04 produced short chain N-butyryl-homoserine lactone (C4-HSL). With the available genome information of C. neteri SSMD04, we went on to analyse and identified a pair of luxI/R homologues in this genome that share the highest similarity with croI/R homologues from Citrobacter rodentium. The AHL synthase, which we named cneI(636 bp), was found in the genome sequences of C. neteri SSMD04. At a distance of 8bp from cneI is a sequence encoding a hypothetical protein, potentially the cognate receptor, a luxR homologue which we named it as cneR. Analysis of this protein amino acid sequence reveals two signature domains, the autoinducer-binding domain and the C-terminal effector which is typical characteristic of luxR. In addition, we found that this genome harboured an orphan luxR that is most closely related to easR in Enterobacter asburiae. To our knowledge, this is the first report on the AHL production activity in C. neteri, and the discovery of its luxI/R homologues, the orphan receptor and its whole genome sequence.

No MeSH data available.


Related in: MedlinePlus