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Role of Tellurite Resistance Operon in Filamentous Growth of Yersinia pestis in Macrophages.

Ponnusamy D, Clinkenbeard KD - PLoS ONE (2015)

Bottom Line: Others have observed a filamentous response associated with expression of tellurite resistance operon in Escherichia coli exposed to tellurite.Further in E. coli, expression of Y. pestis terZAB, but not terCDE, conferred a filamentous phenotype.These findings support the role of Y. pestis terZAB mediation of the filamentous response phenotype; whereas, terCDE confers tellurite resistance.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, United States of America.

ABSTRACT

Background: Yersinia pestis initiates infection by parasitism of host macrophages. In response to macrophage infections, intracellular Y. pestis can assume a filamentous cellular morphology which may mediate resistance to host cell innate immune responses. We previously observed the expression of Y. pestis tellurite resistance proteins TerD and TerE from the terZABCDE operon during macrophage infections. Others have observed a filamentous response associated with expression of tellurite resistance operon in Escherichia coli exposed to tellurite. Therefore, in this study we examine the potential role of Y. pestis tellurite resistance operon in filamentous cellular morphology during macrophage infections.

Principal findings: In vitro treatment of Y. pestis culture with sodium tellurite (Na2TeO3) caused the bacterial cells to assume a filamentous phenotype similar to the filamentous phenotype observed during macrophage infections. A deletion mutant for genes terZAB abolished the filamentous morphologic response to tellurite exposure or intracellular parasitism, but without affecting tellurite resistance. However, a terZABCDE deletion mutant abolished both filamentous morphologic response and tellurite resistance. Complementation of the terZABCDE deletion mutant with terCDE, but not terZAB, partially restored tellurite resistance. When the terZABCDE deletion mutant was complemented with terZAB or terCDE, Y. pestis exhibited filamentous morphology during macrophage infections as well as while these complemented genes were being expressed under an in vitro condition. Further in E. coli, expression of Y. pestis terZAB, but not terCDE, conferred a filamentous phenotype.

Conclusions: These findings support the role of Y. pestis terZAB mediation of the filamentous response phenotype; whereas, terCDE confers tellurite resistance. Although the beneficial role of filamentous morphological responses by Y. pestis during macrophage infections is yet to be fully defined, it may be a bacterial adaptive strategy to macrophage associated stresses.

No MeSH data available.


Related in: MedlinePlus

Cellular morphology of Y. pestis KIM6+ ΔterZABCDE complemented with either terZAB or terCDE in extracellular media.Y. pestis KIM6+ ΔterZABCDE mutant transformed with an empty expression plasmid pMMB67EH (A) or complemented with the expression plasmid carrying Y. pestis terZAB (pYPterZAB) (B) or terCDE (pYPterCDE) (C) genes were cultured in RPMI-1640 media without IPTG. Samples were collected at 2.5 h and observed using Wright Giemsa stain with light microscopy at a magnification of 1,000×.
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pone.0141984.g005: Cellular morphology of Y. pestis KIM6+ ΔterZABCDE complemented with either terZAB or terCDE in extracellular media.Y. pestis KIM6+ ΔterZABCDE mutant transformed with an empty expression plasmid pMMB67EH (A) or complemented with the expression plasmid carrying Y. pestis terZAB (pYPterZAB) (B) or terCDE (pYPterCDE) (C) genes were cultured in RPMI-1640 media without IPTG. Samples were collected at 2.5 h and observed using Wright Giemsa stain with light microscopy at a magnification of 1,000×.

Mentions: The effect of ter complementation on the cellular morphology of the KIM6+ ΔterZABCDE mutant appears complex. In the absence of IPTG induction, the ΔterZABCDE mutant complemented with terZAB exhibited filamentous morphology and the ΔterZABCDE mutant complemented with terCDE exhibited some elongated rods (Fig 5B and 5C). In the presence of 1 mM IPTG inducer, expression of the terZAB and the terCDE in the full-length Y. pestis KIM6+ ΔterZABCDE mutant reduced growth at 24 h by 100% and ≈20%, respectively (S2 Fig). In the presence of 0.05 mM IPTG, the ΔterZABCDE mutant complemented with terZAB exhibited enhanced filamentous cellular morphology compared to its morphology in the absence of IPTG (Fig 6B versus Fig 5B). The ΔterZABCDE mutant complemented with terCDE in the presence of 1mM IPTG showed an altered cellular morphology including some elongated rod forms and altered nucleoid morphology (Fig 6C versus Fig 5C). However, both the ΔterZABCDE mutant complemented with terZAB or terCDE exhibited filamentous cellular morphology intracellularly in RAW 264.7 cells treated with 0.05 mM IPTG (Fig 6E and 6F).


Role of Tellurite Resistance Operon in Filamentous Growth of Yersinia pestis in Macrophages.

Ponnusamy D, Clinkenbeard KD - PLoS ONE (2015)

Cellular morphology of Y. pestis KIM6+ ΔterZABCDE complemented with either terZAB or terCDE in extracellular media.Y. pestis KIM6+ ΔterZABCDE mutant transformed with an empty expression plasmid pMMB67EH (A) or complemented with the expression plasmid carrying Y. pestis terZAB (pYPterZAB) (B) or terCDE (pYPterCDE) (C) genes were cultured in RPMI-1640 media without IPTG. Samples were collected at 2.5 h and observed using Wright Giemsa stain with light microscopy at a magnification of 1,000×.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4633105&req=5

pone.0141984.g005: Cellular morphology of Y. pestis KIM6+ ΔterZABCDE complemented with either terZAB or terCDE in extracellular media.Y. pestis KIM6+ ΔterZABCDE mutant transformed with an empty expression plasmid pMMB67EH (A) or complemented with the expression plasmid carrying Y. pestis terZAB (pYPterZAB) (B) or terCDE (pYPterCDE) (C) genes were cultured in RPMI-1640 media without IPTG. Samples were collected at 2.5 h and observed using Wright Giemsa stain with light microscopy at a magnification of 1,000×.
Mentions: The effect of ter complementation on the cellular morphology of the KIM6+ ΔterZABCDE mutant appears complex. In the absence of IPTG induction, the ΔterZABCDE mutant complemented with terZAB exhibited filamentous morphology and the ΔterZABCDE mutant complemented with terCDE exhibited some elongated rods (Fig 5B and 5C). In the presence of 1 mM IPTG inducer, expression of the terZAB and the terCDE in the full-length Y. pestis KIM6+ ΔterZABCDE mutant reduced growth at 24 h by 100% and ≈20%, respectively (S2 Fig). In the presence of 0.05 mM IPTG, the ΔterZABCDE mutant complemented with terZAB exhibited enhanced filamentous cellular morphology compared to its morphology in the absence of IPTG (Fig 6B versus Fig 5B). The ΔterZABCDE mutant complemented with terCDE in the presence of 1mM IPTG showed an altered cellular morphology including some elongated rod forms and altered nucleoid morphology (Fig 6C versus Fig 5C). However, both the ΔterZABCDE mutant complemented with terZAB or terCDE exhibited filamentous cellular morphology intracellularly in RAW 264.7 cells treated with 0.05 mM IPTG (Fig 6E and 6F).

Bottom Line: Others have observed a filamentous response associated with expression of tellurite resistance operon in Escherichia coli exposed to tellurite.Further in E. coli, expression of Y. pestis terZAB, but not terCDE, conferred a filamentous phenotype.These findings support the role of Y. pestis terZAB mediation of the filamentous response phenotype; whereas, terCDE confers tellurite resistance.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, United States of America.

ABSTRACT

Background: Yersinia pestis initiates infection by parasitism of host macrophages. In response to macrophage infections, intracellular Y. pestis can assume a filamentous cellular morphology which may mediate resistance to host cell innate immune responses. We previously observed the expression of Y. pestis tellurite resistance proteins TerD and TerE from the terZABCDE operon during macrophage infections. Others have observed a filamentous response associated with expression of tellurite resistance operon in Escherichia coli exposed to tellurite. Therefore, in this study we examine the potential role of Y. pestis tellurite resistance operon in filamentous cellular morphology during macrophage infections.

Principal findings: In vitro treatment of Y. pestis culture with sodium tellurite (Na2TeO3) caused the bacterial cells to assume a filamentous phenotype similar to the filamentous phenotype observed during macrophage infections. A deletion mutant for genes terZAB abolished the filamentous morphologic response to tellurite exposure or intracellular parasitism, but without affecting tellurite resistance. However, a terZABCDE deletion mutant abolished both filamentous morphologic response and tellurite resistance. Complementation of the terZABCDE deletion mutant with terCDE, but not terZAB, partially restored tellurite resistance. When the terZABCDE deletion mutant was complemented with terZAB or terCDE, Y. pestis exhibited filamentous morphology during macrophage infections as well as while these complemented genes were being expressed under an in vitro condition. Further in E. coli, expression of Y. pestis terZAB, but not terCDE, conferred a filamentous phenotype.

Conclusions: These findings support the role of Y. pestis terZAB mediation of the filamentous response phenotype; whereas, terCDE confers tellurite resistance. Although the beneficial role of filamentous morphological responses by Y. pestis during macrophage infections is yet to be fully defined, it may be a bacterial adaptive strategy to macrophage associated stresses.

No MeSH data available.


Related in: MedlinePlus