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10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism

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Abstract:

This chapter describes a series of interconnected problems for a range of bacterial, protozoal, and fungal pathogens and explores, in the order in which they are encountered by the pathogen, the consequences of each decision point in the establishment of an intracellular infection. There are three basic mechanisms of invasion: (i) phagocytosis, i.e., entry into professional phagocytes such as macrophages, monocytes, and neutrophils via a process dependent on the host cell contractile system; (ii) induced endocytosis and phagocytosis, i.e., entry into nonprofessional phagocytes by the active induction of internalization through the activity of the host cell contractile system; and (iii) active invasion, i.e., active entry into a passive host cell without triggering any contractile event in the host cell cytoskeleton. The niches exploited by intracellular pathogens fall readily into three different groupings. The first is intralysosomal, in which pathogens persist in acidic, hydrolytic compartments that interact with the endosomal network of the host. The second is intravacuolar, in which pathogens persist in nonacidic vacuoles that exhibit modified or little interaction with the endosomal system of the host. The third is cytoplasmic, in which pathogens exit the phagosome and reside within the host cell cytosol. This chapter has attempted to present the major points in the biology of these pathogens within a thematic framework from the time of initial infection, through the choice of intracellular niche, avoidance or exploitation of the immune response, and culminating in the metastasis or spread of the infection.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Image of Figure 10.1
Figure 10.1

Diagrammatic representation of the three different routes of invasion of mammalian cells by intracellular pathogens. In each instance, the “active” cell or cells are labeled with a plus sign. In phagocytosis, the infecting pathogen is relatively passive in the process following ligation to host cell receptors capable of triggering internalization. This process requires little if any metabolic activity from the parasite. Examples include , and . In induced endocytosis and phagocytosis, the pathogen induces a normally nonphagocytic cell to internalize the microbe. This is the least well understood route of entry and involves subversion of the host cell signaling pathways. Examples include in nonprofessional phagocytes and . In active invasion, the pathogen invades the host cell without the participation of the contractile apparatus of the host cell. In this process, the host cell is inert. Examples include all the apicomplexan parasites, , and microsporidia.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Image of Figure 10.2
Figure 10.2

Electron micrograph of a critical-point dried, detergent-extracted, whole-cell mount of a sporozoite of . The structure of this zoite is typical of that observed throughout the phyla that includes both and . The cell adopts a spiral shape dictated by its subpellicular microtubule network. Motility and host cell invasion are achieved through an actin-myosin contractile system that caps plasmalemma constituents from the anterior to the posterior of the cell.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Figure 10.3

Intracellular niches. Pathogens have evolved to exploit a variety of intracellular locations, which fall readily into three different groups. The first group includes those that reside in acidic, hydrolytically competent lysosomes and appear undeterred by the hostile nature of their compartment. Examples include , and possibly (in macrophages at least). The second group includes those that remain vacuolar yet avoid the normal progression of their vacuole into a lysosomal compartment. This group of pathogens is the most diverse with respect to the nature of their intracellular vacuole. Examples include , and . The third group includes those that avoid the consequence of remaining within a phagocytic vacuole by escaping into the cytoplasm. Examples include , and .

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Figure 10.4

Hoffman modulation contrast micrograph of a monolayer of murine bone marrow-derived macrophages infected with . This species of tends to form large fluid-filled vacuoles that contain multiple parasites, which tend to line up along the periphery of the vacuoles (arrow). The vacuoles are acidic and contain active lysosomal hydrolases.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Image of Figure 10.5
Figure 10.5

induces an extreme response in mammalian cells during entry. In contrast to tight, zippering phagocytosis through which many particles are internalized, these bacteria induce a membrane “splash” or ruffle that captures the bacteria along with an appreciable volume of fluid. This phenomenon is illustrated in a series of time-lapse video frames. The point of initial contact of the bacterium is marked with an arrow in the 30-s and all subsequent time frames. The macropinosome forms (120 s), and several fluid-filled vesicles coalesce (135 and 170 s), until, finally, the phagocytosed bacilli are translocated toward the cell body (250 s). The mechanism appears analogous to the formation of macropinosomes. Courtesy of Hiroshi Morisaki, Michelle Rathman, and John Heuser.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Image of Figure 10.6
Figure 10.6

(A) Electron micrograph of a platinum replica from an isolated -containing phagosome. The view is of the cytoplasmic face of the phagosomal membrane and reveals the atypical smooth texture of the phagosome. (B) Region of an -containing phagosome viewed at comparable magnification. The stud-like structures represent proton-ATPase complexes, which are rare on mycobacterial vacuoles. Proton-ATPases are responsible for the normal acidification of phagosomes. Courtesy of David G. Russell and John Heuser.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Image of Figure 10.7
Figure 10.7

Electron micrograph of a freeze-etch preparation of a HeLa cell infected with . The bacteria (black arrows) form an inclusion body or parasitophorous vacuole (PV) that lies within the host cell cytosol (host cell) and is excluded from the normal endocytic routes of that cell. The vacuole membrane is smooth over most of its surface; however, it is ruffled with processes (white arrows) that extend into the host cell cytoplasm in the region that subtends the host cell endoplasmic reticulum. Courtesy of David G. Russell and Ted Hackstadt.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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Image of Figure 10.9
Figure 10.9

An autoradio electron micrograph of an erythrocyte (RBC) infected with (Plasmodium). The micrograph illustrates the polymerization of hemozoin (arrowed) within the degradative food vacuole (V). The parasite culture was incubated with [H]chloroquine prior to processing, and the antimalarial drug can be seen to localize to the hemozoin polymer. This is consistent with the proposed mode of action of the drug. Courtesy of David G. Russell and Daniel Goldberg.

Citation: Russell D. 2004. 10 Where To Stay inside the Cell: a Homesteader's Guide to Intracellular Parasitism, p 227-253. In Cossart P, Boquet P, Normark S, Rappuoli R (ed), Cellular Microbiology, Second Edition. ASM Press, Washington, DC. doi: 10.1128/9781555817633.ch10
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References

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1. Celli, J.,, C. de Chastellier,, D. M. Franchini,, J. Pizarro-Cerda,, E. Moreno,, and J. P. Gorvel. 2003. Brucella evades macrophage killing via VirB-dependent sustained interactions with the endoplasmic reticulum. J. Exp. Med. 198:545556.
2. Scidmore, M. A.,, and T. Hackstadt. 2001. Mammalian 14-3-3β associates with the Chlamydia trachomatis inclusion membrane via its interaction with IncG. Mol. Microbiol. 39:16381650.
3. van Ooji, C.,, L. Kalman,, S. van Ijzendoorn,, M. Nishijima,, K. Hanada,, K. Mostov,, and J. Engel. 2000. Host cell-derived sphingolipids are required for the intracellular growth of Chlamydia trachomatis. Cell. Microbiol. 2:627637.
4. Luo, Z. Q.,, and R. R. Isberg. 2004. Multiple substrates of the Legionella pneumophila Dot/Icm system identified by interbacterial protein transfer. Proc. Natl. Acad. Sci. USA 101:841846.
5. Nagai, H.,, J. C. Kagan,, X. Zhu,, R. A. Kahn,, and C. R. Roy. 2002. A bacterial guanine nucleotide exchange factor activates ARF on Legionella phagosomes. Science 295: 679682.
6. Sturgill-Koszycki, S.,, and M. S. Swanson. 2000. Legionella pneumophila replication vacuoles mature into acidic, endocytic organelles. J. Exp. Med. 192:12611272.
7. Watarai, M.,, I. Derre,, J. Kirby,, J. D. Growney,, W. F. Dietrich,, and R. R. Isberg. 2001. Legionella pneumophila is internalized by a macropinocytotic uptake pathway controlled by the Dot/Icm system and the mouse Lgn1 locus. J. Exp. Med. 194:10811096. This paper describes the fascinating interplay between host and pathogen at the genetic level. Macropinocytic uptake of the bacterium depends on the expression and function of the dot/icm system. However, the bacterial TTSS is effective only in triggering macropinocytosis in mice homozygotic for the recessive form of the lgn1 locus. This suggests that the lgn1 locus encodes a product that counteracts the bacterial TTSS and renders the host less susceptible to infection.
8. Dermine, J. F.,, S. Scianimanico,, C. Prive,, A. Descoteaux,, and M. Desjardins. 2000. Leishmania promastigotes require lipophosphoglycan to actively modulate the fusion properties of phagosomes at an early stage of phagocytosis. Cell. Microbiol. 2: 115126.
9. Houde, M.,, S. Bertholet,, E. Gagnon,, S. Brunet,, G. Goyette,, A. Laplante,, M. F. Princiotta,, P. Thibault,, D. Sacks,, and M. Desjardins. 2003. Phagosomes are competent organelles for antigen cross-presentation. Nature 425:402406.
10. Wolfram, M.,, M. Fuchs,, M. Wiese,, Y. D. Stierhof,, and P. Overath. 1996. Antigen presentation by Leishmania mexicana-infected macrophages: activation of helper T cells by a model parasite antigen secreted into the parasitophorous vacuole or expressed on the amastigote surface. Eur. J. Immunol. 26:31533162.
11. Glomski, I. J.,, M. M. Gedde,, A. W. Tsang,, J. A. Swanson,, and D. A. Portnoy. 2002. The Listeria monocytogenes hemolysin has an acidic pH optimum to compartmentalize activity and prevent damage to infected host cells. J. Cell. Biol. 156:10291038. Listeriolysin O is a pore-forming toxin released by Listeria to facilitate its escape into the host cell cytoplasm. Interesting questions are why is the activity of this toxin limited to the vacuole membrane, and why does it not kill the cell. Listeria in which LLO had been replaced with the related lysin, perfringolysin O, PFO, did kill the host cell, and it was shown that the differences in amino acid sequence between the two proteins rendered LLO pH sensitive. LLO needs an acid environment to be active and is therefore inactive in the host cell cytosol, whereas PFO retained its activity following escape into the cytosol.
12. Slaghuis, A. A. Szalay, and W. Goebel. 2001. Microinjection and growth of bacteria in the cytosol of mammalian cells. Proc. Natl. Acad. Sci. USA 9:1222112226.
13. Lecuit, M.,, S. Vandormael-Pourin,, J. Lefort,, M. Huerre,, P. Gounon,, C. Dupuy,, C. Babinet,, and P. Cossart. 2001. A transgenic model for Listeriosis: role of internalin in crossing the intestinal barrier. Science 292:17221725. This paper demonstrates the elegant use of transgenic mice to determine the role of a bacterial adhesin in establishment of an infection and invasion of the host. Although internalins had been shown to have a major role in binding to host cells in tissue culture systems, attempts to show their activity in invasion of animal models had met with limited success. In this paper the authors show that the infection of mice by Listeria through internalin activity depended on the expression of the appropriate cadherin. Mice expressing human cadherin were exquisitely sensitive to metastasis, and this invasion and spread were observed only in bacteria expressing internalin.
14. O’Riordan, M.,, M. A. Moors,, and D. A. Portnoy. 2003. Listeria intracellular growth and virulence require host-derived lipoic acid. Science 302:462464.
15. Beatty, W. L.,, E. R. Rhoades,, H. J. Ullrich,, D. Chatterjee,, J. E. Heuser,, and D. G. Russell. 2000. Trafficking and release of mycobacterial lipids from infected macrophages. Traffic 1:235247.
16. Clemens, D. L.,, B. Y. Lee,, and M. A. Horwitz. 2002. The Mycobacterium tuberculosis phagosome in human macrophages is isolated from the host cell cytoplasm. Infect. Immun. 70:58005807.
17. Fratti, R. A.,, J. M. Backer,, J. Gruenberg,, S. Corvera,, and V. Deretic. 2001. Role of phosphatidylinositol 3-kinase and Rab5 effectors in phagosomal biogenesis and mycobacterial phagosome maturation arrest. J. Cell Biol. 154:631644. This paper describes data relevant to determining the exact point of arrest of the maturation of the Mycobacterium-containing phagosome. Following uptake, the Mycobacterium containing phagosome acquired and retained the GTPase Rab5; however, it failed to acquire the PI3P-binding protein EEA1 that is thought to facilitate maturation. PI3P is produced by the phosphatidylinositol 3′-kinase VPS34 that associates transiently with phagosome formed around inert particles and is observed around Mycobacterium-containing vacuoles.
18. McKinney, J. D.,, K. Honer zu Bentrup,, E. J. Munoz-Elias,, A. Miczak,, B. Chen,, W. T. Chan,, D. Swenson,, J. C. Sacchettini,, W. R. Jacobs, Jr.,, and D. G. Russell. 2000. Persistence of Mycobacterium tuberculosis in macrophages and mice requires the glyoxylate shunt enzyme isocitrate lyase. Nature 406:735738. Organisms exploiting fatty acids as their primary carbon source utilize the glyoxylate cycle to facilitate retention of carbon to allow growth. In this paper Mycobacterium organisms deficient in the glyoxylate cycle-gating enzyme, isocitrate lyase, are shown to be defective in survival during the persistent but not the acute phase of infection. The reliance on isocitrate lyase activity can also be demonstrated in activated macrophages in culture. These data indicate that the metabolism of the bacterium changes in response to the changing environment in the activated macrophage and the immune host.
19. Sturgill-Koszycki, S.,, P. H. Schlesinger,, P. Chakraborty,, P. L. Haddix,, H. L. Collins,, A. K. Fok,, R. D. Allen,, S. L. Gluck,, J. Heuser,, and D. G. Russell. 1994. Lack of acidification in Mycobacterium phagosomes produced by exclusion of the vesicular proton-ATPase. Science 263:678681.
20. Vergne, I.,, J. Chua,, and V. Deretic. 2003. Tuberculosis toxin blocking phagosome maturation inhibits a novel Ca2+/calmodulin-PI3K hVPS34 cascade. J. Exp. Med. 198:653659.
21. Banerjee, R.,, J. Liu,, W. Beatty,, L. Pelosof,, M. Klemba,, and D. E. Goldberg. 2002. Four plasmepsins are active in the Plasmodium falciparum food vacuole, including a protease with an active-site histidine. Proc. Natl. Acad. Sci. USA 99:990995.
22. Lauer, S.,, J. VanWye,, T. Harrison,, H. McManus,, B. U. Samuel,, N. L. Hiller,, N. Mohandas,, and K. Haldar. 2000. Vacuolar uptake of host components, and a role for cholesterol and sphingomyelin in malarial infection. EMBO J. 19:35563564.
23. Sullivan, D. J., Jr.,, I. Y. Gluzman,, D. G. Russell,, and D. E. Goldberg. 1996. On the molecular mechanism of chloroquine’s antimalarial action. Proc. Natl. Acad. Sci. USA 93:1186511870.
24. Beuzon, C. R.,, S. Meresse,, K. E. Unsworth,, J. Ruiz-Albert,, S. Garvis,, S. R. Waterman,, T. A. Ryder,, E. Boucrot,, and D. W. Holden. 2000. Salmonella maintains the integrity of its intracellular vacuole through the action of SifA. EMBO J. 19:32353249. Salmonella defective in SifA expression are attenuated for survival inside macrophages. SifA is known to function in the formation of the LAMP-positive filamentous vesicles that associate with Salmonella-containing vacuoles. Close examination of the SifA mutants revealed that the bacteria were loose in the host cell cytosol. These data indicate that SifA function in maintenance of the bacteria-containing vacuoles, possibly through recruitment of membrane. Interestingly, these bacteria did not replicate well in the cytosol of the macrophages, which is in contrast to the study by Brumell in epithelial cells where the bacteria replicated freely.
25. Brumell, J. H.,, P. Tang,, M. L. Zaharik,, and B. B. Finlay. 2002. Disruption of the Salmonella-containing vacuole leads to increased replication of Salmonella enterica serovar Typhimurium in the cytosol of epithelial cells. Infect. Immun. 70:32643270.
26. Ruiz-Albert, J.,, X. J. Yu,, C. R. Beuzon,, A. N. Blakey,, E. E. Galyov,, and D. W. Holden. 2002. Complementary activities of SseJ and SifA regulate dynamics of the Salmonella typhimurium vacuolar membrane. Mol. Microbiol. 44:645661.
27. Vazquez-Torres, A.,, Y. Xu,, J. Jones-Carson,, D. W. Holden,, S. M. Lucia,, M. C. Dinauer,, P. Mastroeni,, and F. C. Fang. 2000. Salmonella pathogenicity island 2-dependent evasion of the phagocyte NADPH oxidase. Science 287:16551658. On ligation of certain receptors during phagocytosis the NADH oxidase complex is formed on the membrane of the nascent phagosome and is transported into the cell on the forming vacuole. This results in localized production of reactive oxygen intermediates that are extremely toxic to bacteria. Salmonella, defective in the expression of SPI-2 genes, are unable to block this process, and recruit the NADH oxidase complex to their phagosome, whereas the wild-type parental strain inhibits acquisition of the complex and survives.
28. Niebuhr, K.,, S. Giuriaqto,, T. Pedron,, D. J. Philpott,, F. Gaits,, J. Sable,, M. P. Sheetz,, C. Parsot,, P. J. Sansonetti,, and B. Payrastre. 2002. Conversion of PtdIns(4,5)P(2) into PtdIns(5) by the S. flexneri effector IpgD reorganizes host cell morphology. EMBO J. 21:50695078. One of the currently emerging themes in microbial pathogenesis is the ability of bacteria to exploit the signaling lipid moieties used by mammalian cells to regulate a range of cellular functions. In this study the bacterial effector IpgD is shown to be a phosphatidylinositol phosphatase that converts PI-4,5P into PI-5P and that this dephosphorylation event induces a profound change in the host cell cytoskeleton.
29. Tran, N.,, A. B. Serfis,, J. C. Osiecki,, W. L. Picking,, L. Coye,, R. Davis,, and W. D. Picking. 2000. Interaction of Shigella flexneri IpaC with model membranes correlates with effects on cultured cells. Infect. Immun. 68:37103715.
30. Charron, A. J.,, and L. D. Sibley. 2002. Host cells: mobilizable lipid resources for the intracellular parasite Toxoplasma gondii. J. Cell Sci. 115:30493059.
31. Hakansson, S.,, A. J. Charron,, and L. D. Sibley. 2001. Toxoplasma evacuoles: a twostep process of secretion and fusion forms the parasitophorous vacuole. EMBO J. 20:31323144.
32. Opitz, C.,, and D. Soldati. 2002. ‘The glideosome’: a dynamic complex powering gliding motion and host cell invasion by Toxoplasma gondii. Mol. Microbiol. 45: 597604. This is the only review cited in the literature section. It is cited because this laboratory has published a fascinating series of papers on the molecular basis of motility and invasion by Toxoplasma gondii, and it would be unfair and misleading to cite one paper without referring to several. Cell movement is pivotal to the infectious nature of this organism, and the contractile system and its expression are so novel they deserve attention.
33. Bielecki, J.,, P. Youngman,, P. Connelly,, and D. A. Portnoy. 1990. Bacillus subtilis expressing a haemolysin gene from Listeria monocytogenes can grow in mammalian cells. Nature 345:175176. In this more recent publication Bielecki and colleagues moved the field forward by showing that the listerolysin O gene from Listeria contained all the information necessary to allow the bacterium to escape from the vacuole and gain access to the cytosol. The LLO gene expressed in B. subtilis redirected the bacillus to the host cell cytoplasm and saved it from certain death within the lysosome.
34. Brown, C. A.,, P. Draper,, and P. D. Hart. 1969. Mycobacteria and lysosomes: a paradox. Nature 221:658660. This is the field in which I work so I may be viewed as somewhat partial; however, for me this paper was way ahead of its time. It set the tone for the cellular microbiology studies that followed it. The senior author, Philip D’Arcy Hart, renowned as the designer of the definitive clinical trial, had retired from leading the MRC Tuberculosis Unit and decided to turn his interests to intracellular survival of Mycobacterium spp. In this early study he demonstrated that the bacilli are sequestered in vacuoles that fail to fuse with lysosomes and that this failure correlated with the viability of the bacteria.
35. Horwitz, M. A.,, and F. R. Maxfield. 1984. Legionella pneumophila inhibits acidification of its phagosome in human monocytes. J. Cell. Biol. 99:19361943. The next paper comes from the work of Horwitz and colleagues who were interested in analysis of the vacuole in which Legionella resides inside phagocytes. This laboratory had noted previously that the mode of uptake of the bacterium was unusual (coiling phagocytosis) and set out to study the vacuole itself as part of a collaboration with a bona fide cell biologist (Maxfield). The result was the accurate pH measurement within the vacuole formed around Legionella, which was significantly higher than the pH values of phagosomes formed around other particles. This represented a new departure for the field.
36. Isberg, R. R.,, and S. Falkow. 1985. A single genetic locus encoded by Yersinia pseudotuberculosis permits invasion of cultured animal cells by Escherichia coli K-12. Nature 317:262264. This paper, and the following one by Sansonetti and colleagues, marked the next step forward, that is, the combination of bacterial genetics and cell biology in the design of a genetic screen to identify, in this instance, the invasin genes in Yersinia. Isberg and Falkow transformed Escherichia coli with the shot-gunned genome of Yersinia, incubated the bacteria with cells, and then exploited the hydrophilic nature of gentamycin to kill extracellular bacteria and select for clones that encoded host cell entry. The result was a classic publication exploiting and combining a range of disciplines and laying the groundwork for an emerging field.
37. Sansonetti, P. J.,, A. Ryter,, P. Clerc,, A. T. Maurelli,, and J. Mounier. 1986. Multiplication of Shigella flexneri within HeLa cells: lysis of the phagocytic vacuole and plasmid- mediated contact hemolysis. Infect. Immun. 51:461469. Similarly, Sansonetti and colleagues used classic bacterial genetics and transconjugation to transfer the “virulence” plasmid of Shigella into E. coli. On examination, the modified E. coli were found to be free in the host cell cytoplasm, demonstrating that the plasmid from Shigella encoded the capacity to allow the bacterium to escape from the phagosome and attain access to the host cell cytoplasm. Like the preceding publication, this represented a saccadic leap in the field and laid the foundation for “Cellular Microbiology.”

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