Limits...
Identification of vacuoles containing extraintestinal differentiated forms of Legionella pneumophila in colonized Caenorhabditis elegans soil nematodes.

Hellinga JR, Garduño RA, Kormish JD, Tanner JR, Khan D, Buchko K, Jimenez C, Pinette MM, Brassinga AK - Microbiologyopen (2015)

Bottom Line: A previous study employing the metazoan Caenorhabditis elegans, a member of the Rhabditidae family of free-living soil nematodes, demonstrated that the intestinal lumen can be colonized with L. pneumophila.While both replicative forms and differentiated forms were observed in C. elegans, these morphologically distinct forms were initially observed to be restricted to the intestinal lumen.Furthermore, establishment of LCVs in the gonadal tissue was Dot/Icm dependent and required the presence of the endocytic factor RME-1 to gain access to maturing oocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2.

No MeSH data available.


Related in: MedlinePlus

Legionella pneumophila invades the Caenorhabditis elegans intestinal cells. Representative transmission electron microscopy images were obtained from samples of nematodes fed L. pneumophila Lp02 for 6 days. (A) Longitudinal section of colonized intestine. Note the typical rod-shaped morphology of the bacteria within the intestinal lumen defined by the microvilli (MV) intestinal epithelium lined by the MV. Scale bar is 2 μm. (B) Embedding of the bacteria within the MV on the apical surface of the intestinal cell (IC) supported by the terminal web (TW). Note the poly-β-hydoxybutyrate inclusion bodies (white spots) within some of the bacterial forms. Scale bar is 500 nm. (C) Disruption of the electron dense intermediate filaments of the TW from the MV on the apical surface of the IC. Note the presence of the bacterial form with poly-β-hydoxybutyrate inclusion (inc) bodies embedded in the MV. Scale bar is 500 nm. (D) Internalization of a bacterial form (white arrow) within the IC. Note that the shape and size of the internalized bacterial form is similar to bacterial forms (white arrow) present within the intestinal lumen. Also note that the MV with the supporting TW appears to have re-formed. Scale bar is 500 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4554460&req=5

fig07: Legionella pneumophila invades the Caenorhabditis elegans intestinal cells. Representative transmission electron microscopy images were obtained from samples of nematodes fed L. pneumophila Lp02 for 6 days. (A) Longitudinal section of colonized intestine. Note the typical rod-shaped morphology of the bacteria within the intestinal lumen defined by the microvilli (MV) intestinal epithelium lined by the MV. Scale bar is 2 μm. (B) Embedding of the bacteria within the MV on the apical surface of the intestinal cell (IC) supported by the terminal web (TW). Note the poly-β-hydoxybutyrate inclusion bodies (white spots) within some of the bacterial forms. Scale bar is 500 nm. (C) Disruption of the electron dense intermediate filaments of the TW from the MV on the apical surface of the IC. Note the presence of the bacterial form with poly-β-hydoxybutyrate inclusion (inc) bodies embedded in the MV. Scale bar is 500 nm. (D) Internalization of a bacterial form (white arrow) within the IC. Note that the shape and size of the internalized bacterial form is similar to bacterial forms (white arrow) present within the intestinal lumen. Also note that the MV with the supporting TW appears to have re-formed. Scale bar is 500 nm.

Mentions: The presence of LCVs in the C. elegans gonadal tissue poses the question of how Lp02 bacteria are able to gain access to the gonadal tissue from the colonized intestinal tract. Additionally, does the bacteria differentiate while enroute to the gonadal tissue or remain static in their morphological form when leaving the colonized intestinal tract? To answer these questions, TEM was employed in order to track the probable progress of the bacteria from the colonized intestinal tract to the gonadal tissue and analyze the ultrastructural features to determine the developmental stage of L. pneumophila forms based on previously defined morphological criteria. A longitudinal TEM section illustrates the dense packing of Lp02 bacteria in the intestinal lumen of a colonized nematode (Fig.7A). A magnified focused view on a section of the intestinal epithelium shows that the majority of Lp02 bacteria in the intestinal lumen feature a mixture of replicative, stationary phase forms (some featuring PHBA inclusion bodies) (Fig.7B) (Faulkner and Garduño 2002; Brassinga et al. 2010). In addition, embedment of Lp02 bacteria were frequently observed within the microvilli that extend from the apical surface to form a brush border suggesting that Lp02 bacteria have the ability to penetrate the glycocalyx electron-lucent coating of highly modified glycoproteins termed glycocalyx covering the microvilli (Fig.7B) (Lehane 1997; McGhee 2007).


Identification of vacuoles containing extraintestinal differentiated forms of Legionella pneumophila in colonized Caenorhabditis elegans soil nematodes.

Hellinga JR, Garduño RA, Kormish JD, Tanner JR, Khan D, Buchko K, Jimenez C, Pinette MM, Brassinga AK - Microbiologyopen (2015)

Legionella pneumophila invades the Caenorhabditis elegans intestinal cells. Representative transmission electron microscopy images were obtained from samples of nematodes fed L. pneumophila Lp02 for 6 days. (A) Longitudinal section of colonized intestine. Note the typical rod-shaped morphology of the bacteria within the intestinal lumen defined by the microvilli (MV) intestinal epithelium lined by the MV. Scale bar is 2 μm. (B) Embedding of the bacteria within the MV on the apical surface of the intestinal cell (IC) supported by the terminal web (TW). Note the poly-β-hydoxybutyrate inclusion bodies (white spots) within some of the bacterial forms. Scale bar is 500 nm. (C) Disruption of the electron dense intermediate filaments of the TW from the MV on the apical surface of the IC. Note the presence of the bacterial form with poly-β-hydoxybutyrate inclusion (inc) bodies embedded in the MV. Scale bar is 500 nm. (D) Internalization of a bacterial form (white arrow) within the IC. Note that the shape and size of the internalized bacterial form is similar to bacterial forms (white arrow) present within the intestinal lumen. Also note that the MV with the supporting TW appears to have re-formed. Scale bar is 500 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4554460&req=5

fig07: Legionella pneumophila invades the Caenorhabditis elegans intestinal cells. Representative transmission electron microscopy images were obtained from samples of nematodes fed L. pneumophila Lp02 for 6 days. (A) Longitudinal section of colonized intestine. Note the typical rod-shaped morphology of the bacteria within the intestinal lumen defined by the microvilli (MV) intestinal epithelium lined by the MV. Scale bar is 2 μm. (B) Embedding of the bacteria within the MV on the apical surface of the intestinal cell (IC) supported by the terminal web (TW). Note the poly-β-hydoxybutyrate inclusion bodies (white spots) within some of the bacterial forms. Scale bar is 500 nm. (C) Disruption of the electron dense intermediate filaments of the TW from the MV on the apical surface of the IC. Note the presence of the bacterial form with poly-β-hydoxybutyrate inclusion (inc) bodies embedded in the MV. Scale bar is 500 nm. (D) Internalization of a bacterial form (white arrow) within the IC. Note that the shape and size of the internalized bacterial form is similar to bacterial forms (white arrow) present within the intestinal lumen. Also note that the MV with the supporting TW appears to have re-formed. Scale bar is 500 nm.
Mentions: The presence of LCVs in the C. elegans gonadal tissue poses the question of how Lp02 bacteria are able to gain access to the gonadal tissue from the colonized intestinal tract. Additionally, does the bacteria differentiate while enroute to the gonadal tissue or remain static in their morphological form when leaving the colonized intestinal tract? To answer these questions, TEM was employed in order to track the probable progress of the bacteria from the colonized intestinal tract to the gonadal tissue and analyze the ultrastructural features to determine the developmental stage of L. pneumophila forms based on previously defined morphological criteria. A longitudinal TEM section illustrates the dense packing of Lp02 bacteria in the intestinal lumen of a colonized nematode (Fig.7A). A magnified focused view on a section of the intestinal epithelium shows that the majority of Lp02 bacteria in the intestinal lumen feature a mixture of replicative, stationary phase forms (some featuring PHBA inclusion bodies) (Fig.7B) (Faulkner and Garduño 2002; Brassinga et al. 2010). In addition, embedment of Lp02 bacteria were frequently observed within the microvilli that extend from the apical surface to form a brush border suggesting that Lp02 bacteria have the ability to penetrate the glycocalyx electron-lucent coating of highly modified glycoproteins termed glycocalyx covering the microvilli (Fig.7B) (Lehane 1997; McGhee 2007).

Bottom Line: A previous study employing the metazoan Caenorhabditis elegans, a member of the Rhabditidae family of free-living soil nematodes, demonstrated that the intestinal lumen can be colonized with L. pneumophila.While both replicative forms and differentiated forms were observed in C. elegans, these morphologically distinct forms were initially observed to be restricted to the intestinal lumen.Furthermore, establishment of LCVs in the gonadal tissue was Dot/Icm dependent and required the presence of the endocytic factor RME-1 to gain access to maturing oocytes.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2.

No MeSH data available.


Related in: MedlinePlus