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Joseph EP, Camejo-Harry M, Christopher T, Contreras-Arratia R, Edwards S, Graham O, Johnson M, Juman A, Latchman JL, Lynch L, Miller VL, Papadopoulos I, Pascal K, Robertson R, Ryan GA, Stinton A, Grandin R, Hamling I, Jo MJ, Barclay J, Cole P, Davies BV, Sparks RSJ. Responding to eruptive transitions during the 2020-2021 eruption of La Soufrière volcano, St. Vincent. Nat Commun 2022; 13:4129. [PMID: 35840594 PMCID: PMC9287448 DOI: 10.1038/s41467-022-31901-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 07/08/2022] [Indexed: 11/09/2022] Open
Abstract
A critical challenge during volcanic emergencies is responding to rapid changes in eruptive behaviour. Actionable advice, essential in times of rising uncertainty, demands the rapid synthesis and communication of multiple datasets with prognoses. The 2020-2021 eruption of La Soufrière volcano exemplifies these challenges: a series of explosions from 9-22 April 2021 was preceded by three months of effusive activity, which commenced with a remarkably low level of detected unrest. Here we show how the development of an evolving conceptual model, and the expression of uncertainties via both elicitation and scenarios associated with this model, were key to anticipating this transition. This not only required input from multiple monitoring datasets but contextualisation via state-of-the-art hazard assessments, and evidence-based knowledge of critical decision-making timescales and community needs. In addition, we share strategies employed as a consequence of constraints on recognising and responding to eruptive transitions in a resource-constrained setting, which may guide similarly challenged volcano observatories worldwide.
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Affiliation(s)
- E P Joseph
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.
| | - M Camejo-Harry
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.,Department of Earth Science, University of Oxford, Oxford, OX1 3AN, UK
| | - T Christopher
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.,Montserrat Volcano Observatory, Flemmings, Montserrat
| | - R Contreras-Arratia
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - S Edwards
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - O Graham
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - M Johnson
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - A Juman
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - J L Latchman
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - L Lynch
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - V L Miller
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.,Montserrat Volcano Observatory, Flemmings, Montserrat
| | - I Papadopoulos
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - K Pascal
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.,Montserrat Volcano Observatory, Flemmings, Montserrat
| | - R Robertson
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago
| | - G A Ryan
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.,Montserrat Volcano Observatory, Flemmings, Montserrat
| | - A Stinton
- Seismic Research Centre, The University of the West Indies, St. Augustine, Trinidad and Tobago.,Montserrat Volcano Observatory, Flemmings, Montserrat
| | - R Grandin
- Université de Paris, Institut de Physique du Globe de Paris, CNRS, F-75005, Paris, France
| | - I Hamling
- GNS Science, Lower Hutt, New Zealand
| | - M-J Jo
- USRA, NASA-GSFC, Greenbelt, MD, USA
| | - J Barclay
- School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - P Cole
- School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, UK
| | - B V Davies
- School of Environmental Sciences, University of East Anglia, Norwich, UK
| | - R S J Sparks
- School of Earth Sciences, University of Bristol, Bristol, BS8 1 R J, UK
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Lee WL, Watauchi S, Miller VL, Cava RJ, Ong NP. Anomalous hall heat current and nernst effect in the CuCr2Se4-xBrx ferromagnet. Phys Rev Lett 2004; 93:226601. [PMID: 15601108 DOI: 10.1103/physrevlett.93.226601] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Indexed: 05/24/2023]
Abstract
In a ferromagnet, an anomalous Hall heat current, given by the off-diagonal Peltier term alpha(xy), accompanies the anomalous Hall current. By combining Nernst, thermopower, and Hall experiments, we have measured how alpha(xy) varies with hole density and lifetime tau in CuCr2Se4-xBrx. At low temperatures T, we find that alpha(xy) is independent of tau, consistent with anomalous-velocity theories. Its magnitude is fixed by a microscopic geometric area A approximately 34 A(2). Our results are incompatible with some models of the Nernst effect in ferromagnets.
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Affiliation(s)
- Wei-Li Lee
- Department of Physics, Princeton University, New Jersey 08544, USA
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Abstract
In a ferromagnet, an applied electric field E invariably produces an anomalous Hall current JH that flows perpendicular to the plane defined by E and M (the magnetization). For decades, the question of whether JH is dissipationless (independent of the scattering rate) has been debated without experimental resolution. In the ferromagnetic spinel CuCr2Se4-xBrx, the resistivity rho (at low temperature) may be increased by several decades by varying x (Br) without degrading M. We show that JH/E (normalized per carrier, at 5 kelvin) remains unchanged throughout. In addition to confirming the dissipationless nature of JH, our finding has implications for the generation and study of spin-Hall currents in bulk samples.
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Affiliation(s)
- Wei-Li Lee
- Department of Physics, Princeton University, Princeton, NJ 08544, USA
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Abstract
The genus Yersinia is composed of 11 species, three of which are pathogenic in humans. The three pathogens, Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis, cause a broad spectrum of disease ranging from pneumonic plague to acute gastroenteritis. Each of the three requires a large, well-defined plasmid for full virulence, as well as many chromosomally encoded virulence factors (CEVF). This review will describe these CEVF and their roles in virulence. In addition, a possible model for key events in Y. enterocolitica pathogenesis is described based on information revealed by analysis of several of the CEVF.
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Affiliation(s)
- P A Revell
- Department of Molecular Microbiology and Pediatrics, Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8208, St. Louis, MO 63110, USA
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Kolodny N, Kitov S, Vassell MA, Miller VL, Ware LA, Fegeding K, De La Vega P, Sacci JB, Lanar DE. Two-step chromatographic purification of recombinant Plasmodium falciparum circumsporozoite protein from Escherichia coli. J Chromatogr B Biomed Sci Appl 2001; 762:77-86. [PMID: 11589461 DOI: 10.1016/s0378-4347(01)00340-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The Plasmodium falciparum circumsporozoite (PfCS) protein (aa 19-405) has been cloned and expressed in E. coli. The protein was purified in a two-step process that was rapid and reproducible. E. coli cells were grown to a high density before induction for 1 h. Cells were disrupted by high pressure microfluidization and the total bacterial protein solubilized in 6 M Gu-HCl. The protein was refolded while bound to Ni-NTA agarose by exchange of 6 M Gu-HCl for 8 M urea and then slow removal of the urea. The eluted protein was further purified on Q Sepharose Fast Flow using conditions developed to remove E. coli proteins and reduce endotoxin (to 10 EU/50 microg). Yield was 20 mg of PfCS protein from 10 g of wet cell paste. The final protein product bound to HepG2 liver cells in culture and inhibited the invasion of those cells by sporozoites in an ISI assay greater than 80% over control cultures when used at 10 microg/ml.
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Affiliation(s)
- N Kolodny
- Department of Immunology, Walter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA
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Nelson KM, Young GM, Miller VL. Identification of a locus involved in systemic dissemination of Yersinia enterocolitica. Infect Immun 2001; 69:6201-8. [PMID: 11553561 PMCID: PMC98752 DOI: 10.1128/iai.69.10.6201-6208.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2001] [Accepted: 06/18/2001] [Indexed: 11/20/2022] Open
Abstract
A putative LysR-type transcriptional activator, Hre20, was identified previously in an in vivo expression technology screen designed to identify factors which are expressed early during infection by Yersinia enterocolitica (G. M. Young and V. L. Miller, Mol. Microbiol. 25:319-328, 1997). An insertion in hre20, now designated rscR, resulted in increased splenic dissemination of bacteria during infection in a BALB/c mouse model. A nonpolar mutation was generated in rscR, and examination of this strain in the BALB/c mouse model demonstrated that the mutation in rscR was responsible for the increased dissemination to the spleen that was seen in the original experiments. RscR is homologous to the LysR family of transcriptional regulators; thus, a screen was undertaken to identify genes regulated by RscR. A strain containing an insertion in the chromosomal rscR gene and carrying rscR on a plasmid under the control of the inducible araBAD promoter was mutagenized with an mTn5Km-2 transposon containing a promoterless lacZY. Eighteen insertions were identified which appeared to respond to levels of RscR, and these were classified into four allelic groups based on Southern blot hybridization analysis. Representative members were sequenced from three allelic groups. Sequencing revealed insertions in an ORF with no known homologues, a homologue of OmpF of Serratia marcescens, and a locus (designated rscBAC) with similarity to the hmwABC locus of Haemophilus influenzae. The hmwABC locus promotes adherence of H. influenzae to host cells (S. J. Barenkamp and J. W. St. Geme III, Infect. Immun. 62:3320-3328, 1994; J. W. St. Geme III, S. Falkow, and S. J. Barenkamp, Proc. Natl. Acad. Sci. USA 90:2875-2879, 1993). A strain containing a deletion mutant of rscA, the hmwA homologue, exhibits increased splenic dissemination of bacteria during infection in a BALB/c mouse model, similar to the rscR mutant. This suggests that the phenotype of an rscR mutant is due to the loss of RscA.
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Affiliation(s)
- K M Nelson
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Dube PH, Revell PA, Chaplin DD, Lorenz RG, Miller VL. A role for IL-1 alpha in inducing pathologic inflammation during bacterial infection. Proc Natl Acad Sci U S A 2001; 98:10880-5. [PMID: 11526216 PMCID: PMC58568 DOI: 10.1073/pnas.191214498] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Infection with pathogenic microbes often results in a significant inflammatory response. A cascade of proinflammatory cytokines including tumor necrosis factor alpha (TNF-alpha) and IL-1 initiates this response. Although there is a clear role for IL-1 during infection, little is known to distinguish the role of IL-1 alpha from that of IL-1 beta during this process. With the use of Yersinia enterocolitica as a model enteric pathogen, we have identified a specific role for IL-1 alpha in inducing pathologic inflammation during bacterial infection. Depletion of IL-1 alpha in mice infected with wild-type Y. enterocolitica results in significantly decreased intestinal inflammation. Furthermore, a bacterial mutant that does not induce IL-1 alpha expression but induces normal levels of IL-1 beta, TNF-alpha, and IFN-gamma, causes greatly reduced intestinal inflammation and is attenuated by LD(50) analysis in the C57BL/6 mouse model. These results demonstrate a distinct and unrecognized role for IL-1 alpha in inducing intestinal inflammation that cannot be compensated for by the endogenous levels of IL-1 beta, TNF-alpha, or IFN-gamma that are produced in response to Y. enterocolitica. Additionally, these results suggest that IL-1 alpha-induced inflammation is a major contributor to the pathology of yersiniosis.
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Affiliation(s)
- P H Dube
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Abstract
Yersinia enterocolitica is an enteric pathogen that has served as a model system for the study of microbial pathogenesis. Numerous virulence gene have been identified both on the virulence plasmid and on the chromosome. One of the chromosomal genes that is highly correlated with virulence is ail, a gene identified along with inv in a screen for Y. enterocolitica genes that could confer an invasive phenotype to Escherichia coli. Ail also promotes serum resistance in both E. coli and Y. enterocolitica. Several virulence factors homologous to Ail have been identified in other pathogens, yet very little is known about what constitutes the functional domain(s) of these proteins. Proteins in this family are predicted to consist of eight transmembrane beta-sheets and four cell surface-exposed loops. We constructed and characterized a number of insertion, deletion and point mutations in the regions of ail predicted to encode the cell surface loops. The results from the analysis of these mutants indicate that cell surface loops one and four do not directly promote invasion or serum resistance, whereas mutations in loop three appear to modulate both phenotypes. Analysis of mutations in loop 2 suggests that this surface-exposed loop contains sequences required for serum resistance and invasion. In addition, a peptide derived from the sequence of loop 2 was able specifically to inhibit Ail-mediated invasion in a dose-dependent manner. These results suggest that Ail directly promotes invasion and that loop 2 contains an active site, perhaps a receptor-binding domain. Analyses of the mutations also suggest that the serum resistance and invasion phenotypes may be separable, because there are numerous mutations that affect one phenotype but not the other.
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Affiliation(s)
- V L Miller
- Department of Microbiology and Molecular Genetics, University of California at Los Angeles, Los Angeles, CA 90095, USA.
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Heusipp G, Young GM, Miller VL. HreP, an in vivo-expressed protease of Yersinia enterocolitica, is a new member of the family of subtilisin/kexin-like proteases. J Bacteriol 2001; 183:3556-63. [PMID: 11371518 PMCID: PMC95231 DOI: 10.1128/jb.183.12.3556-3563.2001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The role of proteases in pathogenesis is well established for several microorganisms but has not been described for Yersinia enterocolitica. Previously, we identified a gene, hreP, which showed significant similarity to proteases in a screen for chromosomal genes of Y. enterocolitica that were exclusively expressed during an infection of mice. We cloned this gene by chromosome capture and subsequently determined its nucleotide sequence. Like inv, the gene encoding the invasin protein of Y. enterocolitica, hreP is located in a cluster of flagellum biosynthesis and chemotaxis genes. The genomic organization of this chromosomal region is different in Escherichia coli, Salmonella, and Yersinia pestis than in Y. enterocolitica. Analysis of the distribution of hreP between different Yersinia isolates and the relatively low G+C content of the gene suggests acquisition by horizontal gene transfer. Sequence analysis also revealed that HreP belongs to a family of eukaryotic subtilisin/kexin-like proteases. Together with the calcium-dependent protease PrcA of Anabaena variabilis, HreP forms a new subfamily of bacterial subtilisin/kexin-like proteases which might have originated from a common eukaryotic ancestor. Like other proteases of this family, HreP is expressed with an N-terminal prosequence. Expression of an HreP-His(6) tag fusion protein in E. coli revealed that HreP undergoes autocatalytic processing at a consensus cleavage site of subtilisin/kexin-like proteases, thereby releasing the proprotein.
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Affiliation(s)
- G Heusipp
- Department of Molecular Microbiology, Washington University School of Medicine and St. Louis Children's Hospital, St. Louis, Missouri 63110, USA
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Miller VL, Chan PJ, Jacobson JD, Patton WC, King A. A comparison of heat-induced hyperactivation in patients' sperm after colloid or pentoxifylline wash methods. Am J Obstet Gynecol 2001; 184:1057-9. [PMID: 11349155 DOI: 10.1067/mob.2001.114505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Our purpose was to compare kinematic parameters of human sperm after processing through two different wash methods and 40 degrees C heat treatment. STUDY DESIGN Sperm specimens (N = 169 cases) were washed by either colloid or pentoxifylline wash methods, and the motility parameters were measured at either 37 degrees C or 40 degrees C at baseline (0 hours) and after 4 hours. Five randomly selected washed specimens with matching 37 degrees C (control) or 40 degrees C heat treatments were assessed for changes in a sentinel gene. RESULTS The percentage of sperm hyperactive motility was >5 times higher after the 40 degrees C heat treatment, in comparison with the 37 degrees C treatment, for both the colloid- and the pentoxifylline-washed sperm. The percentages of total motility and progression were equally enhanced in heated sperm for the two wash methods. No changes were detected in the sentinel gene with the heat treatment. CONCLUSION Sperm cells mildly heated at 40 degrees C responded with greater motility, progression, and hyperactivation. The data suggest that mild heat is a stimulus for sperm function because greater sperm hyperactivation is associated with increased sperm fertilizing capacity. The absence of change in the sentinel gene in heated sperm suggests that a temperature of 40 degrees C is too low to initiate alterations in the highly condensed sperm chromatin. More studies are needed before mild heating of ejaculated sperm becomes acceptable for use in assisted reproductive technologies.
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Affiliation(s)
- V L Miller
- Department of Gynecology and Obstetrics, Loma Linda University School of Medicine, California 92350, USA
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Abstract
SigD is translocated into eucaryotic cells by a type III secretion system. In this work, evidence that the putative chaperone SigE directly interacts with SigD is presented. A bacterial two-hybrid system demonstrated that SigE can interact with itself and SigD. In addition, SigD was specifically copurified with SigE-His(6) on a nickel column.
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Affiliation(s)
- K H Darwin
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Darwin AJ, Miller VL. The psp locus of Yersinia enterocolitica is required for virulence and for growth in vitro when the Ysc type III secretion system is produced. Mol Microbiol 2001; 39:429-44. [PMID: 11136463 DOI: 10.1046/j.1365-2958.2001.02235.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The phage shock protein locus (pspFpspABCDE) of Escherichia coli has proved to be something of an enigma since its discovery. The physiological functions of the psp locus, including those of the predicted effector protein PspA, are unknown. In a previous genetic screen, we determined that a Yersinia enterocolitica pspC mutant was severely attenuated for virulence. In this study, the psp locus of Y. enterocolitica was characterized further. The pspC gene of Y. enterocolitica was found to be important for normal growth when the Ysc type III secretion system was expressed in the laboratory. This growth defect was specifically caused by production of the secretin protein, YscC. Expression of the psp genes was induced when the type III secretion system was functional or when only the yscC gene was expressed. This induction of psp gene expression required a functional pspC gene. Most significantly, evidence suggests that the expression of at least one gene that is not part of the psp locus is regulated by Psp proteins. This unidentified gene (or genes) may also be important for growth when the type III secretion system is expressed. These conclusions are supported by the effects of various psp mutations on virulence. This is the first indication that Psp proteins might be involved in the regulation of genes besides the psp locus itself.
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Affiliation(s)
- A J Darwin
- Department of Molecular Microbiology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8208, St Louis, MO 63110, USA
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Abstract
Yersinia enterocolitica is one of three pathogenic Yersinia species that share a tropism for lymphoid tissues. However, infection of an immunocompromised host is likely to result in a systemic infection, which is often fatal. Little is known about the bacterial proteins needed to establish such an infection. The genes that encode these virulence factors are likely to be active only during systemic infection. A library of random cat fusions was used to inoculate BALB/c mice. Fusions expressed during a systemic infection were enriched by the administration of chloramphenicol-succinate. Y. enterocolitica isolates recovered from the mice were tested for chloramphenicol resistance in vitro. Fusions that were inactive in vitro were analyzed further and found to represent 31 allelic groups. Each was given a sif (for systemic infection factor) designation. Based on homology to known proteins, the sif genes are likely to encode proteins important for general physiology, transcription regulation, and other functions. During systemic infections, 13 of the sif-cat fusions were able to outcompete the wild type in the presence of chloramphenicol-succinate, confirming that the fusions were active. The in vitro expression of several sif genes was determined, showing modest changes in response to various growth conditions. A mutation in sif15, which encodes a putative outer membrane protein, caused attenuation during systemic infection but not during colonization of the Peyer's patches. Comparisons between the Y. enterocolitica sif genes and the previously identified hre genes imply that very different groups of genes are active during a systemic infection and during colonization of the Peyer's patches.
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Affiliation(s)
- A S Gort
- Department of Molecular Microbiology and Division of Infectious Disease, Washington University School of Medicine, and St. Louis Children's Hospital, St. Louis, Missouri 63130, USA
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Abstract
Dimorphism is an essential feature of Histoplasma capsulatum pathogenesis, and much attention has been focused on characteristics that are unique to the saprophytic mycelial phase or the parasitic yeast phase. Recently, we identified a secreted calcium-binding protein, CBP, that is produced in large amounts by yeast cells but is undetectable in mycelial cultures. In this study, the green fluorescent protein (GFP) was established as a reporter in H. capsulatum to study regulation of CBP1 expression in cultures and in single cells grown under different conditions and inside macrophages. One GFP version that was optimized for human codon usage yielded highly fluorescent Histoplasma yeast cells. By monitoring GFP fluorescence during the transition from mycelia to yeast, we demonstrated that the CBP1 promoter is only fully active after complete morphological conversion to the yeast form, indicating for the first time that CBP1 is developmentally regulated rather than simply temperature regulated. Continuous activity of the CBP1 promoter during infection of macrophages supports the hypothesis that CBP secretion plays an important role for Histoplasma survival within the phagolysosome. Broth cultures of Histoplasma yeasts carrying a CBP-GFP protein fusion construct were able to secrete a full-length fluorescent fusion protein that remained localized within the phagolysosomes of infected macrophages. Additionally, a comparison of two Histoplasma strains carrying the CBP1 promoter fusion construct either epichromosomally or integrated into the chromosome revealed cell-to-cell variation in plasmid copy number due to uneven plasmid partitioning into daughter cells.
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Affiliation(s)
- S Kügler
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Abstract
The purpose of this study was to examine the influence of sociodemographic factors, attitudes, knowledge, and experiences regarding the use of various contraceptive methods, future plans prenatally, and actual use postpartum among a population of low income pregnant women. Women were interviewed prenatally and during the postpartum period in a large, urban academic health center serving primarily an indigent population. The primary analytic method employed was logistic regression. The key finding in this study is that women are not consistently using the method of contraception postpartum that they planned during the prenatal period. Only 54.7% of the women planning to use oral contraceptive pills were using them postpartum, and only 31.3% of the women planning to use condoms were actually using them postpartum. Expanding contraceptive education and counseling throughout the perinatal period may assist women's decision making.
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Affiliation(s)
- V L Miller
- Department of OB/GYN and Center for Healthcare Effectiveness Research, Wayne State University, School of Medicine, Detroit, Michigan 48201, USA
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Badger JL, Young BM, Darwin AJ, Miller VL. Yersinia enterocolitica ClpB affects levels of invasin and motility. J Bacteriol 2000; 182:5563-71. [PMID: 10986262 PMCID: PMC111002 DOI: 10.1128/jb.182.19.5563-5571.2000] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2000] [Accepted: 07/13/2000] [Indexed: 11/20/2022] Open
Abstract
Expression of the Yersinia enterocolitica inv gene is dependent on growth phase and temperature. inv is maximally expressed at 23 degrees C in late-exponential- to early-stationary-phase cultures. We previously reported the isolation of a Y. enterocolitica mutant (JB1A8v) that shows a decrease in invasin levels yet is hypermotile when grown at 23 degrees C. JB1A8v has a transposon insertion within uvrC. Described here is the isolation and characterization of a clone that suppresses these mutant phenotypes of the uvrC mutant JB1A8v. This suppressing clone encodes ClpB (a Clp ATPase homologue). The Y. enterocolitica ClpB homologue is 30 to 40% identical to the ClpB proteins from various bacteria but is 80% identical to one of the two ClpB homologues of Yersinia pestis. A clpB::TnMax2 insertion mutant (JB69Qv) was constructed and determined to be deficient in invasin production and nonmotile when grown at 23 degrees C. Analysis of inv and fleB (flagellin gene) transcript levels in JB69Qv suggested that ClpB has both transcriptional and posttranscriptional effects. In contrast, a clpB null mutant, BY1v, had no effect on invasin levels or motility. A model accounting for these observations is presented.
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Affiliation(s)
- J L Badger
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
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Young GM, Badger JL, Miller VL. Motility is required to initiate host cell invasion by Yersinia enterocolitica. Infect Immun 2000; 68:4323-6. [PMID: 10858252 PMCID: PMC101757 DOI: 10.1128/iai.68.7.4323-4326.2000] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2000] [Accepted: 03/29/2000] [Indexed: 01/18/2023] Open
Abstract
Invasin-mediated invasion of host cells by the pathogen Yersinia enterocolitica was shown to be affected by flagellar-dependent motility. Motility appears to be required to ensure the bacterium migrates to and contacts the host cell. Nonmotile strains of Y. enterocolitica were less invasive than motile strains, but the reduction in invasion could be overcome by artificially bringing the bacteria into host cell contact by centrifugation. Mutations in known regulatory genes of the flagellar regulon, flhDC and fliA, resulted in less inv expression but did not have a significant effect on invasin levels. However, invasin levels were reduced for strains that harbored flhDC on a multicopy plasmid, apparently as a result of increased proteolysis of invasin.
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Affiliation(s)
- G M Young
- Department of Molecular Microbiology, Department of Pediatrics, Washington University School of Medicine and St. Louis Children's Hospital, St. Louis, Missouri 63110, USA
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Abstract
OBJECTIVE This study was undertaken to compare the birth outcomes of a multifetal pregnancy reduction population with those of other patients delivered at Hutzel Hospital, Detroit, and to determine the fiscal impact of the multifetal pregnancy reduction program. STUDY DESIGN In a retrospective review patients who were delivered after multifetal pregnancy reduction were compared with a general obstetric population who were delivered at Hutzel Hospital from January 1, 1986, through June 30, 1998. Outcome data were determined through a comprehensive perinatal database. The chi(2) analysis was used to examine the relationship between gestational age and delivery group. Financial data were estimated from published reports of neonatal intensive care unit admissions, cost estimates for neonatal intensive care unit care, and charges for multifetal pregnancy reduction. RESULTS Pregnancies reduced to triplets, twins, and singletons had outcomes at least comparable to unreduced pregnancies starting at these numbers and substantially better than unreduced pregnancies with the same starting number. Financial estimates of hospitalization costs averted in the multifetal pregnancy reduction population exceeded $28 million. CONCLUSION Use of multifetal pregnancy reduction improved obstetric outcomes for pregnancies with multiple gestations and also was associated with significant fiscal savings.
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Affiliation(s)
- V L Miller
- Departments of Obstetrics and Gynecology, Molecular Medicine and Genetics, and Pathology, Wayne State University Hutzel Hospital, Detroit, MI, USA
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Miller VL, Ransom SB, Ayoub MA, Krivchenia EL, Evans MI. Fiscal impact of a potential legislative ban on second trimester elective terminations for prenatally diagnosed abnormalities. Am J Med Genet 2000; 91:359-62. [PMID: 10766999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
This study was designed to determine the fiscal impact of a theoretical legislative ban on elective terminations for prenatally diagnosed abnormalities at Hutzel Hospital/Wayne State University. A fiscal comparison was completed for patients who had second trimester elective terminations for prenatally diagnosed abnormalities versus not allowing the procedure. An eight-year database of genetics cases and hospital and physician cost estimates for performing elective terminations for prenatally diagnosed abnormalities, and published reports of the average lifetime costs per selected birth defects, were used to calculate the net cost. The estimated lifetime cost for an average cohort year of a legislative ban on elective terminations for prenatally diagnosed abnormalities was found to be at least $8.5 million for patients treated at Hutzel Hospital. Extrapolated, a similar ban on second trimester elective terminations would have a net cost of $74 million in Michigan and $2 billion annually in the United States.
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Affiliation(s)
- V L Miller
- Department of Obstetrics and Gynecology, Wayne State University/Hutzel Hospital, Detroit, Michigan, USA
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Schmiel DH, Young GM, Miller VL. The Yersinia enterocolitica phospholipase gene yplA is part of the flagellar regulon. J Bacteriol 2000; 182:2314-20. [PMID: 10735878 PMCID: PMC111284 DOI: 10.1128/jb.182.8.2314-2320.2000] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/1999] [Accepted: 01/27/2000] [Indexed: 11/20/2022] Open
Abstract
Yersinia enterocolitica yplA encodes a phospholipase required for virulence. Virulence genes are often regulated in response to environmental signals; therefore, yplA expression was examined using a yplA::lacZY transcriptional fusion. Maximal yplA expression occurred between pH 6.5 and pH 7.5 and was induced in the mid-logarithmic growth phase. Potential Fnr, cyclic AMP (cAMP)-cAMP receptor protein (Crp), and sigma(F) regulatory sites were identified in the nucleotide sequence. Reduction of yplA expression by aeration, addition of glucose and sucrose, and application of high temperature and salt is consistent with Fnr-, cAMP-Crp-, and sigma(F)-mediated regulation, respectively. Expression of yplA was reduced in flhDC and fliA null strains, indicating that yplA is part of the flagellar regulon.
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Affiliation(s)
- D H Schmiel
- Department of Molecular Microbiology, Department of Pediatrics, Washington University School of Medicine, Missouri 63110, USA
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28
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Abstract
The primary invasion factor of Yersinia enterocolitica, invasin, is encoded by inv. inv expression is regulated in response to pH, growth phase and temperature. In vitro, inv is maximally expressed at 26 degrees C, pH 8.0, or 37 degrees C, pH 5.5, in early stationary phase. At 37 degrees C, pH 8.0, inv is weakly expressed. To identify which gene(s) are required for inv regulation, we screened for transposon insertions that decreased expression of an inv-'phoA chromosomal reporter at 26 degrees C. Of 30 000 mutants screened, two were identified that had negligible inv expression in all conditions tested. Both of these independent mutants had an insertion into the same gene, designated rovA (regulator of virulence). RovA has 77% amino acid identity to the Salmonella typhimurium transcriptional regulator SlyA. Complementation with the wild-type rovA allele restores wild-type inv expression as monitored by Western blot analysis, tissue culture invasion assay and alkaline phosphatase assay. There is also a significant decrease in invasin levels in bacteria recovered from mice infected with the rovA mutant; therefore, RovA regulates inv expression in vivo as well as in vitro. In the mouse infection model, an inv mutant has a wild-type LD50, even though the kinetics of infection is changed. In contrast, the rovA mutant has altered kinetics, as well as a 70-fold increase in the LD50 compared with wild type. Furthermore, because the rovA mutant is attenuated in the mouse model, this suggests that RovA regulates other virulence factors in addition to inv. Analysis of other proposed virulence factors such as Ail, YadA and the Yop proteins shows no regulatory role for RovA. The more severe animal phenotype combined with the lack of impact on known virulence genes aside from inv suggests RovA regulates potentially novel virulence genes of Y. enterocolitica during infection.
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Affiliation(s)
- P A Revell
- Department of Molecular Microbiology and Pediatrics, Campus Box 8230, Washington University School of Medicine, St. Louis, MO 63110, USA
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Darwin KH, Miller VL. The putative invasion protein chaperone SicA acts together with InvF to activate the expression of Salmonella typhimurium virulence genes. Mol Microbiol 2000; 35:949-60. [PMID: 10692170 DOI: 10.1046/j.1365-2958.2000.01772.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SigD and SigE (Salmonella invasion gene) are proteins needed for optimal invasion of Salmonella typhimurium into eukaryotic cells in vitro. SigD is a secreted protein and SigE is a putative chaperone required for SigD stability and/or secretion. SigD is secreted by a type III secretion apparatus encoded within a pathogenicity island on the Salmonella chromosome known as Salmonella pathogenicity island 1 (SPI1). The expression of sigDE, which is not linked to SPI1, is co-ordinately regulated with the SPI1 genes and is dependent on the transcriptional regulators SirA, HilA and InvF. These three proteins alone are unable to activate transcription from the sigD promoter in Escherichia coli, therefore it is likely that other factors are needed for expression. A screen for genes required for the expression of a sigD-lacZYA reporter fusion found a mutant with a transposon insertion in spaS, an SPI1 gene which encodes a putative inner-membrane component of the type III secretion system. The expression of a SPI1 operon encoding a putative chaperone (SicA) and several secreted proteins (Sips B, C, D and A) was also reduced in this mutant. The regulation defect of the spaS mutant was complemented by sicA and not by spaS. Because sicA is encoded immediately downstream of spaS, the mutation in spaS was likely to be polar on the expression of sicA. In addition, a sicA disruption mutant was as defective as an invF deletion mutant for the expression of sigD, sicA and sipC reporter fusions. The introduction of plasmids encoding invF and sicA into a non-pathogenic E. coli K-12 strain stimulated the transcription of both a sicA- and a sigD-lacZYA promoter fusion. This result suggests that InvF and SicA are sufficient for the expression of these genes. This is the first demonstration of a positive regulatory role for a putative type III secretion system chaperone in the expression of virulence genes.
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Affiliation(s)
- K H Darwin
- Division of Infectious Disease, Departments of Pediatrics and Molecular Microbiology, Washington University School of Medicine and St. Louis Children's Hospital, St. Louis, MO 63110, USA
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30
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Abstract
Phospholipases are produced from a diverse group of bacterial pathogens causing very different diseases. In some cases, secreted phospholipases appear to be the major cause of pathophysiological effects. Yet in other cases, phospholipases are key virulence factors, contributing to bacterial survival or dissemination without causing tissue destruction. Perhaps the most intriguing aspect of phospholipases as virulence factors is their potential to interfere with cellular signaling cascades and to modulate the host immune response.
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Affiliation(s)
- D H Schmiel
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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31
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Darwin KH, Miller VL. InvF is required for expression of genes encoding proteins secreted by the SPI1 type III secretion apparatus in Salmonella typhimurium. J Bacteriol 1999; 181:4949-54. [PMID: 10438766 PMCID: PMC93983 DOI: 10.1128/jb.181.16.4949-4954.1999] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The expression of genes encoding proteins secreted by the SPI1 (Salmonella pathogenicity island) type III secretion apparatus is known to require the transcriptional activators SirA and HilA. However, neither SirA nor HilA is believed to directly activate the promoters of these genes. invF, the first gene of the inv-spa gene cluster, is predicted to encode an AraC-type transcriptional activator and is required for invasion into cultured epithelial cells. However, the genes which are regulated by InvF have not been identified. In this work, an in-frame deletion in invF was constructed and tested for the expression of Phi(sigD-lacZYA), sipC::Tn5lacZY, and a plasmid-encoded Phi(sicA-lacZYA). SigD (Salmonella invasion gene) is a secreted protein required for the efficient invasion of Salmonella typhimurium into cultured eucaryotic cells. sicA (Salmonella invasion chaperone) is the first gene of a putative operon encoding the Sip/Ssp (Salmonella invasion/Salmonella secreted proteins) invasion proteins secreted by the SPI1 type III export apparatus. invF was required for the expression of the sigD, sicA, and sipC fusions. This is the first demonstration that there is a functional promoter in the intergenic sequence between spaS and sicA. In addition, several proteins were either absent from or found in reduced amounts in the culture supernatants of the invF mutant. Therefore, invF is required for the optimal expression of several genes encoding SPI1-secreted proteins. Genetic evidence is also presented suggesting there is HilA-dependent readthrough transcription from the invF promoter at least through sipC.
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Affiliation(s)
- K H Darwin
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
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32
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Abstract
Salmonella is one of the most extensively characterized bacterial pathogens and is a leading cause of bacterial gastroenteritis. Despite this, we are only just beginning to understand at a molecular level how Salmonella interacts with its mammalian hosts to cause disease. Studies during the past decade on the genetic basis of virulence of Salmonella have significantly advanced our understanding of the molecular basis of the host-pathogen interaction, yet many questions remain. In this review, we focus on the interaction of enterocolitis-causing salmonellae with the intestinal mucosa, since this is the initiating step for most infections caused by Salmonella. Animal and in vitro cell culture models for the interaction of these bacteria with the intestinal epithelium are reviewed, along with the bacterial genes that are thought to affect this interaction. Lastly, recent studies on the response of epithelial cells to Salmonella infection and how this might promote diarrhea are discussed.
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Affiliation(s)
- K H Darwin
- Departments of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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33
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Young GM, Schmiel DH, Miller VL. A new pathway for the secretion of virulence factors by bacteria: the flagellar export apparatus functions as a protein-secretion system. Proc Natl Acad Sci U S A 1999; 96:6456-61. [PMID: 10339609 PMCID: PMC26903 DOI: 10.1073/pnas.96.11.6456] [Citation(s) in RCA: 292] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/1999] [Accepted: 03/22/1999] [Indexed: 11/18/2022] Open
Abstract
Biogenesis of the flagellum, a motive organelle of many bacterial species, is best understood for members of the Enterobacteriaceae. The flagellum is a heterooligomeric structure that protrudes from the surface of the cell. Its assembly initially involves the synthesis of a dedicated protein export apparatus that subsequently transports other flagellar proteins by a type III mechanism from the cytoplasm to the outer surface of the cell, where oligomerization occurs. In this study, the flagellum export apparatus was shown to function also as a secretion system for the transport of several extracellular proteins in the pathogenic bacterium Yersinia enterocolitica. One of the proteins exported by the flagellar secretion system was the virulence-associated phospholipase, YplA. These results suggest type III protein secretion by the flagellar system may be a general mechanism for the transport of proteins that influence bacterial-host interactions.
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Affiliation(s)
- G M Young
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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34
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Young GM, Smith MJ, Minnich SA, Miller VL. The Yersinia enterocolitica motility master regulatory operon, flhDC, is required for flagellin production, swimming motility, and swarming motility. J Bacteriol 1999; 181:2823-33. [PMID: 10217774 PMCID: PMC93725 DOI: 10.1128/jb.181.9.2823-2833.1999] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability to move over and colonize surface substrata has been linked to the formation of biofilms and to the virulence of some bacterial pathogens. Results from this study show that the gastrointestinal pathogen Yersinia enterocolitica can migrate over and colonize surfaces by swarming motility, a form of cooperative multicellular behavior. Immunoblot analysis and electron microscopy indicated that swarming motility is dependent on the same flagellum organelle that is required for swimming motility, which occurs in fluid environments. Furthermore, motility genes such as flgEF, flgMN, flhBA, and fliA, known to be required for the production of flagella, are essential for swarming motility. To begin to investigate how environmental signals are processed and integrated by Y. enterocolitica to stimulate the production of flagella and regulate these two forms of cell migration, the motility master regulatory operon, flhDC, was cloned. Mutations within flhDC completely abolished swimming motility, swarming motility, and flagellin production. DNA sequence analysis revealed that this locus is similar to motility master regulatory operons of other gram-negative bacteria. Genetic complementation and functional analysis of flhDC indicated that it is required for the production of flagella. When flhDC was expressed from an inducible ptac promoter, flagellin production was shown to be dependent on levels of flhDC expression. Phenotypically, induction of the ptac-flhDC fusion also corresponded to increased levels of both swimming and swarming motility.
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Affiliation(s)
- G M Young
- Departments of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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35
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Abstract
Pathogenic Yersinia species are associated with both localized and systemic infections in mammalian hosts. In this study, signature-tagged transposon mutagenesis was used to identify Yersinia enterocolitica genes required for survival in a mouse model of infection. Approximately 2000 transposon insertion mutants were screened for attenuation. This led to the identification of 55 mutants defective for survival in the animal host, as judged by their ability to compete with the wild-type strain in mixed infections. A total of 28 mutants had transposon insertions in the virulence plasmid, validating the screen. Two of the plasmid mutants with severe virulence defects had insertions in an uncharacterized region. Several of the chromosomal insertions were in a gene cluster involved in O-antigen biosynthesis. Other chromosomal insertions identified genes not previously demonstrated as being required for in vivo survival of Y. enterocolitica. These include genes involved in the synthesis of outer membrane components, stress response and nutrient acquisition. One severely attenuated mutant had an insertion in a homologue of the pspC gene (phage shock protein C) of Escherichia coli. The phage shock protein operon has no known biochemical or physiological function in E. coli, but is apparently essential for the survival of Y. enterocolitica during infection.
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Affiliation(s)
- A J Darwin
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
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36
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Abstract
Caring for technology-dependent infants with bronchopulmonary dysplasia requires a wide range and intense level of services. Case management programs can offer comprehensive services to patients with complex needs. The Neonatal Pulmonary Program at Tulane University Medical Center is a case management program for infants with chronic pulmonary problems. The purpose of this study was to describe the costs of providing care for technology-dependent infants with bronchopulmonary dysplasia and to include the direct and indirect costs to families as well as the Program costs. The study population included 89 infants enrolled in the program from September 1987 through February 1992. Outpatient, inpatient, and professional staff costs were derived from hospital and clinic billing information; all other costs were determined through family interviews. Total costs for outpatient services were $59,627 (89), professional team members time $185,539 (89); inpatient services $1,144,930 (89), professional costs for inpatient services $88,946; direct health costs $32,543 (37) for home health care, equipment, medications, special diets; direct non-health costs $30,670 (37) for transportation, meals, child care, lodging during clinic visits and rehospitalizations and household expenses to accommodate equipment needs; and indirect costs $26,173 (37) for missed work days and employment changes.
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Affiliation(s)
- V L Miller
- Department of Obstetrics & Gynecology, Wayne State University, Detroit, MI 48201, USA
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37
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Schmiel DH, Wagar E, Karamanou L, Weeks D, Miller VL. Phospholipase A of Yersinia enterocolitica contributes to pathogenesis in a mouse model. Infect Immun 1998; 66:3941-51. [PMID: 9673284 PMCID: PMC108459 DOI: 10.1128/iai.66.8.3941-3951.1998] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/1998] [Accepted: 05/11/1998] [Indexed: 02/08/2023] Open
Abstract
Some isolates of Yersinia enterocolitica exhibit phospholipase activity, which has been linked to lecithin-dependent hemolysis (M. Tsubokura, K. Otsoki, I. Shimohira, and H. Yamamoto, Infect. Immun. 25:939-942, 1979). A gene encoding Y. enterocolitica phospholipase was identified, and analysis of the nucleotide sequence revealed two tandemly transcribed open reading frames. The first, yplA, has 74% identity and 85% similarity to the phospholipase A found in Serratia liquefaciens. Though the other, yplB, was less similar to the downstream accessory protein found in S. liquefaciens, the organization in both species is similar. Subsequently, a yplA-null Y. enterocolitica strain, YEDS10, was constructed and demonstrated to be phospholipase negative by plate and spectrophotometric assays. To ascertain whether the phospholipase has a role in pathogenesis, YEDS10 was tested in the mouse model. In experiments with perorally infected BALB/c mice, fewer YEDS10 organisms were recovered from the mesenteric lymph nodes and Peyer's patches (PP) than the parental strain at 3 or 5 days postinfection. Furthermore, bowel tissue and PP infected with YEDS10 appeared to be less inflamed than those infected with the parental strain. When extremely high doses of both the parental and YEDS10 strains were given, similar numbers of viable bacteria were recovered from the PP and mesenteric lymph nodes on day 3. However, the numbers of foci and the extent of inflammation and necrosis within them were noticeably less for YEDS10 compared to the parental strain. Together these findings suggest that Y. enterocolitica produces a phospholipase A which has a role in pathogenesis.
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Affiliation(s)
- D H Schmiel
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
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38
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Feuerstein M, Miller VL, Burrell LM, Berger R. Occupational upper extremity disorders in the federal workforce. Prevalence, health care expenditures, and patterns of work disability. J Occup Environ Med 1998; 40:546-55. [PMID: 9636935 DOI: 10.1097/00043764-199806000-00007] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Upper extremity disorders (UEDs) account for a significant number of work-related illnesses in the US workforce. Little information exists on the distribution of UEDs, their associated health care and indemnity costs, or patterns of work disability. The study presented is an analysis of upper extremity claims within the federal workforce. In this study, the universe consisted of all claims accepted by the US Department of Labor, Office of Workers' Compensation Programs (OWCP), from October 1, 1993, through September 30, 1994. A total of 185,927 claims of notices of injury were processed during the study period, and of these, 8,147 or 4.4% had an UED diagnosis coded according to the International Classification of Diseases, Clinical Modification (ICD-9-CM). 5,844 claims involved a single UED diagnosis and were the only claims field by these employees between October 1, 1990, and September 30, 1994. These single claims with single diagnoses comprised the sample for further analysis. Mononeuritis and enthesopathies of the upper limb were the most common diagnoses, accounting for 43% and 31% of the claims, respectively. Women had a higher proportion of carpal tunnel syndrome, "unspecified" mononeuritis, and "unspecified" enthesopathies. The majority of claimants for both the mononeuritis- and enthesopathy-related diagnoses were between 31 and 50 years of age, received only health care benefits, and did not incur wage loss. Health care costs for mononeuritis and enthesopathy claims were $12,228,755 (M = $2,849). Carpal tunnel syndrome (CTS) and enthesopathy of the elbow were the most costly diagnoses, accounting for 57% and 16% of the total, respectively. Surgical services represented the highest expenditures in CTS claims. Physical therapy accounted for the majority of health care costs for enthesopathy cases. The mean number of workdays lost for CTS and enthesopathy claims were 84 and 79, and the average indemnity costs were $4,941 and $4,477, respectively. These findings indicate that while UEDs represent a relatively small percentage of all workers' compensation cases, the health care and indemnity costs are considerable. Also mean duration and pattern of work disability revealed that these disorders can result in chronic work disability similar to that observed in low back pain. The results highlight the need to determine whether interventions that account for the majority of costs significantly impact long-term outcomes. There is also a need to identify risk factors for prolonged disability in those who experience problems with delayed recovery.
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Affiliation(s)
- M Feuerstein
- Department of Medical and Clinical Psychology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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39
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Abstract
Genes essential for Salmonella typhimurium invasion have been localized to Salmonella pathogenicity island 1 (SPI1) on the chromosome. However, it is clear that other genes are required for the invasion process. Mutations that abolish the SPI1 invasion type III secretion system do not significantly reduce invasion into Chinese hamster ovary tissue culture cells. Two invasion defective mutants were isolated by screening 2,500 Tn10dTc insertion mutants of S. typhimurium in the tissue culture invasion assay. One of the invasion mutants, SVM167, has an insertion between centisomes 24.5 and 25.5 in an operon homologous to the ipgDEF operon of the Shigella flexneri and Shigella sonnei virulence plasmid. A second mutant, SVM168, has an insertion in an IS3-type element with homology to the Salmonella enteritidis IS1351 element and Yersinia enterocolitica IS1400 element from a high-pathogenicity island. Further characterization of SVM167 showed that culture supernatants from this mutant lack a previously uncharacterized protein that is also missing from culture supernatants of a SPI1 mutant, suggesting it can be secreted by the SPI1 type III secretion system. In addition, transcription of this operon, sigDE (Salmonella invasion gene), is dependent on the presence of sirA, an activator of hilA expression. HilA activates transcription of several of the SPI1 genes but does not appear to have a major role in activation of transcription from the sigDE promoter.
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Affiliation(s)
- K H Hong
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, 90095, USA
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40
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Abstract
The Yersinia enterocolitica inv gene encodes the primary invasion factor invasin, which has been previously shown to be critical in the initial stages of infection. The expression of inv is influenced by growth phase and temperature and is maximal during late exponential-early stationary phase at 23 degrees C. In addition, motility of Y. enterocolitica is regulated by temperature. Y. enterocolitica cells are motile when grown at lower temperatures (30 degrees C or below), while bacteria grown at 37 degrees C are nonmotile. This study was initiated to determine the molecular basis for the temperature regulation of inv expression. Two mutants were isolated that both showed a significant decrease in invasin expression but are hypermotile when grown at 23 degrees C. The first mutant (JB1A8v) was a result of a random mTn5Km insertion into the uvrC gene. The uvrC mutant JB1A8v demonstrated a significant decrease in inv and an increase in fleB (encodes flagellin) expression. These results suggest that expression of inv and flagellin genes is coordinated at the level of transcription. The second regulatory mutant, JB16v, was a result of a targeted insertion into a locus similar to sspA which in E. coli encodes a stationary-phase regulator. The E. coli sspA gene was cloned and assayed for complementation in both of the regulatory mutants. It was determined that E. coli sspA restored invasin expression in both the uvrC mutant and the sspA mutant. In addition, the complementing clone decreased flagellin levels in these mutants.
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Affiliation(s)
- J L Badger
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90095, USA
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41
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Abstract
Pathogenic species of the genus Yersinia have a marked tropism for lymphoid tissue during the early stages of infection. Bacterial survival at this site determines whether the disease is localized or progresses systemically, leading to a high rate of mortality. Several plasmid-encoded virulence genes are known to be required for survival and pathogenesis, but the contribution of chromosomal genes has been largely unexplored. This study represents the first intensive effort to characterize and determine the function of Yersinia chromosomal genes expressed in lymphoid tissue after intragastric infection. Strains harbouring cat fusions expressed in the host were isolated from Peyer's patch tissue of mice intragastrically infected and treated with chloramphenicol (Cm); genes identified in this manner were designated hre for host responsive element. The hre::cat strains that were Cm resistant in vivo (in mouse tissue) and Cm sensitive in vitro (on laboratory media at 26 degrees C) were identified and shown to consist of 61 different allelic groups. The hre::cat fusions from 48 of the allelic groups were cloned and characterized by DNA sequence analysis. The results identified genes necessary for iron acquisition, protection from environmental stresses, biosynthesis of cell envelope components and other diverse metabolic activities. However, the DNA sequence of many clones had no homology to other known genes. Insertion mutations were constructed for four hre genes and the resulting Y. enterocolitica mutants were tested in the mouse model for effects on pathogenesis. All of the mutant strains were affected for virulence when assayed for survival in host tissues and LD50 analysis.
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Affiliation(s)
- G M Young
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90095, USA
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42
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Abstract
Yersinia pseudotuberculosis and Yersinia enterocolitica are closely related human pathogens causing gastroenteritis. Invasin and YadA are two of the most extensively studied virulence factors of the Yersinia genus. Invasin is the primary invasion factor encoded by the inv gene on the chromosome and is required for the penetration of the epithelial cells. YadA is encoded by the yadA gene on the 70-kb virulence plasmid and has multiple functions. Previous studies indicate that an inv yadA double mutant of Y. enterocolitica is avirulent while an inv yadA mutant of Y. pseudotuberculosis is hypervirulent. In this study, we investigated this unexpected difference. New constructs of the inv yadA mutants of Y. pseudotuberculosis were made and tested in mice. These new constructs were not hypervirulent; rather, they maintained the same virulence as the wild-type strain. Further examination of the inv mutant used for the previous study revealed that it carries an aberrant inv phenotype and has an altered outer membrane profile and an altered colony morphology. Therefore, the mutants used previously were not isogenic to the parental wild-type strain, which may in part account for the difference in the results obtained.
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Affiliation(s)
- Y W Han
- Department of Microbiology and Molecular Genetics, University of California-Los Angeles, 90095, USA
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43
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Abstract
To infect a susceptible host, the gastrointestinal pathogen Yersinia enterocolitica must survive passage through the acid environment of the stomach. In this study, we showed that Y. enterocolitica serotype O8 survives buffered acidic conditions as low as pH 1.5 for long periods of time provided urea is available. Acid tolerance required an unusual cytoplasmically located urease that was activated 780-fold by low-pH conditions. Acid tolerance of Helicobacter species has also been attributed to urease activity, but in that case urease was not specifically activated by low-pH conditions. A ure mutant strain of Y. enterocolitica was constructed which was hypersensitive to acidic conditions when urea was available and, unlike the parental strain, was unable to grow when urea was the sole nitrogen source. Examination of other urease-producing gram-negative bacteria indicated that Morganella morganii survives in acidic conditions but Escherichia coli 1021, Klebsiella pneumoniae, Proteus mirabilis, Providencia stuartii, and Pseudomonas aeruginosa do not. Consistent with these results, biochemical evidence demonstrated that Y. enterocolitica and M. morganii ureases were activated in vitro by low pH with an unusually low activity optimum of pH 5.5. In whole cells activation occurred as medium values decreased below pH 3.0 for Y. enterocolitica and pH 5.5 for M. morganii, suggesting that in vivo activation occurs as a result of cytoplasmic acidification. DNA sequence analysis of portions of the M. morganii ure locus showed that the predicted primary structure of the enzyme structural subunits is most similar to those of Y. enterocolitica urease. One region of similarity between these two ureases located near the active site is distinct from most other ureases but is present in the urease of Lactobacillus fermentum. This region of similarity may be responsible for the unique properties of the Y. enterocolitica and M. morganii ureases since the L. fermentum urease also has been shown to have a low pH optimum for activity.
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Affiliation(s)
- G M Young
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles, 90095, USA
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44
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Abstract
Temperature is a key environmental cue for Yersinia enterocolitica as well as for the two other closely related pathogens, Yersinia pestis and Yersinia pseudotuberculosis. Between the range of 30 degrees C and 37 degrees C, Y. enterocolitica phase-varies between motility and plasmid-encoded virulence gene expression. To determine how temperature regulates Y. enterocolitica motility, we have been dissecting the flagellar regulatory hierarchy to determine at which level motility is blocked by elevated temperature (37 degrees C). Here we report the cloning, DNA sequences, and regulation of the two main regulators of Class III flagellar genes, fliA (sigma F) and flgM (anti-sigma F), and a third gene, flgN, which we show is required for filament assembly. Identification of the Y. enterocolitica fliA and flgM genes was accomplished by functional complementation of both S. typhimurium and Y. enterocolitica mutations and by DNA sequence analysis. The Y. enterocolitica fliA gene, encoding the flagellar-specific sigma-factor, sigma F, maps immediately downstream of the three flagellin structural genes. The flgM and flgN genes, encoding anti-sigma F and a gene product required for filament assembly, respectively, map downstream of the invasin (inv) gene but are transcribed in the opposite (convergent) direction. By using Northern blot analyses we show that transcription of both fliA and flgM is immediately arrested when cells are exposed to 37 degrees C, coincident with the timing of virulence gene induction. Unlike S. typhimurium flgM mutants, Y. enterocolitica flgM mutants are fully virulent.
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Affiliation(s)
- V Kapatral
- Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, Moscow 83843, USA
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45
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Abstract
It has been hypothesized for many years that the ability of Yersinia spp. to invade tissue culture cells is reflective of their ability to penetrate the intestinal epithelium and that this capacity is an important aspect of the disease process. Three different genes from Yersinia spp. that are involved in the tissue culture invasion phenotype have been identified: inv, ail, and yadA. It was previously shown that inv is necessary for efficient penetration of the intestinal epithelium by Yersinia enterocolitica. The present study was initiated to determine whether other known Yersinia invasion factors could promote uptake of the bacteria by mice in the absence of invasion. In addition, the roles of these three invasion factors in the survival of the bacteria, lethality for mice, and development of pathology were compared. We found that YadA is necessary for persistence of Y. enterocolitica in Peyer's patches, and consistent with this observation, the yadA mutant was avirulent for mice infected either orally or intraperitoneally. In addition, the inv yadA double mutant was avirulent. Histological and immunohistological examination of the Peyer's patches of infected mice indicated that despite the presence of large numbers of CFU at 24 h the yadA and ail yadA mutants cause only minimal pathology and recruitment of macrophages. At 42 h postinfection, Peyer's patches from mice infected with the inv mutant showed no pathology, despite the prediction that some of the mice by this time would be colonized. However, at 72 h, inflammation and necrosis were evident in some Peyer's patches. Together, these observations suggest that for visible pathology to develop, a threshold number of bacteria (> 10(5)) is needed and the bacteria need to persist for more than 24 h. Lastly, YadA but not Ail may play a role in the less efficient, delayed invasion of the intestinal epithelium observed for the inv mutant.
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Affiliation(s)
- J C Pepe
- Department of Microbiology & Molecular Genetics, University of California at Los Angeles 90095, USA
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46
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Abstract
rpoS, a gene that encodes an alternative sigma factor (also known as katF), is critical for the ability of Yersinia enterocolitica grown at 37 degrees C, but not at 26 degrees C, to survive diverse environmental insults such as high temperature, hydrogen peroxide, osmolarity, and low pH. However, a Y. enterocolitica rpoS mutant was not affected in expression of inv or ail, invasion of tissue culture cells, or virulence in mice.
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Affiliation(s)
- J L Badger
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90095, USA
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47
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Abstract
The ability of Salmonella to invade tissue culture cells is correlated with virulence. Therefore, the tissue culture invasion model has been used extensively to study this process and to identify the bacterial genes involved and their products. Described here is the further characterization of a Salmonella enteritidis mutant (SM6T) originally identified as a non-invasive for tissue culture cells. A chromosomal DNA fragment complementing this defect was cloned and sequenced. The derived protein sequence is 89% identical to TolC from Escherichia coli, an outer membrane protein required for the signal peptide-independent transport of alpha-haemolysin and colicin V. Therefore, sinA was renamed tolC and is referred to in this text as tolCs to distinguish it from tolC of E. coli. TolCs and TolC are functionally similar since tolC can complement the invasion-defective phenotype of a tolCs mutant, and tolCs is required for export of alpha-haemolysin by Salmonella. The tolCs mutant is avirulent for mice when administered by the oral route, suggesting that the gene is important for virulence. Further characterization of the tolCs mutant indicated that like tolC mutants it is more sensitive than the wild-type strain to various detergents, antibiotics and dyes. This mutant is more sensitive to Triton X-100 only when associated with the monolayer, and the invasion-defective phenotype appears to be artifact of this sensitivity. In addition, the tolCs mutant is more sensitive to the bactericidal activity of human serum. Therefore, the avirulent phenotype could be the result of an inability to secrete a necessary virulence factor, or an increased sensitivity to complement and detergents as a result of a subtle alteration in the lipopolysaccharide (LPS) associated with tolC mutations.
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Affiliation(s)
- B J Stone
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90095, USA
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48
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Abstract
Ail is a 17-kDa protein of Yersinia enterocolitica previously identified on the basis of its ability to confer upon Escherichia coli the phenotype of attachment and invasion of cultured epithelial cells. Here we report an examination of the contribution of ail to the pathogenicity of Y. enterocolitica. A low-copy-number ail plasmid that promoted serum resistance in E. coli HB101 was constructed. The serum resistance phenotype conferred by ail to E. coli was affected by the growth phase of the culture as well as by the gene copy number. In contrast, the copy number of ail (and the relative quantity of Ail) was found to have little effect on the amount of Ail-promoted invasion of cultured epithelial cells. An ail mutant of Y. enterocolitica was constructed and characterized in vitro. This mutant produced no detectable Ail and had a reduced ability to invade CHO cells. Serum resistance of Y. enterocolitica was Ail dependent and was affected by growth phase and ail copy number. The phenotype of the ail mutant was examined in vivo by using a murine model for infection. The ail mutant phenotype was identical to that of the wild-type strain in oral 50% lethal dose studies and early colonization of Peyer's patches as well as in kinetic studies. Western blot (immunoblot) analysis of Ail produced by bacteria growing in vivo at 48 h postinfection indicated that ail was expressed at this time point. Thus, our findings confirm that Ail contributes to the serum resistance and invasion phenotypes of Y. enterocolitica in vitro and indicate that Ail is not required to establish an infection or to cause systemic infection of BALB/c or DBA/2 mice.
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Affiliation(s)
- M R Wachtel
- Department of Microbiology and Molecular Genetics, University of California, Los Angeles 90095, USA
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49
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Abstract
Although widely used, tissue-culture assays cannot be exact models of the conditions that are met in vivo by pathogenic bacteria. However, recent studies of specific mutants suggest that the model is good for highly invasive bacteria, but it remains to be seen if this is true for weakly invasive bacteria.
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Affiliation(s)
- V L Miller
- University of California, Los Angeles, Dept. of Microbiology and Molecular Genetics 90024-1489, USA
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50
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Mixter PF, Camerini V, Stone BJ, Miller VL, Kronenberg M. Mouse T lymphocytes that express a gamma delta T-cell antigen receptor contribute to resistance to Salmonella infection in vivo. Infect Immun 1994; 62:4618-21. [PMID: 7927728 PMCID: PMC303151 DOI: 10.1128/iai.62.10.4618-4621.1994] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mice depleted of lymphocytes expressing the alpha beta or the gamma delta T-cell receptor for antigen (TCR) by antibody treatment were infected orally with Salmonella enteritidis. In both groups of treated mice, the 50% lethal dose decreased, suggesting that both the alpha beta TCR+ and the gamma delta TCR+ subsets contribute to resistance to oral infection. These data provide further evidence for the contribution of gamma delta T cells in the response to bacterial infections.
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Affiliation(s)
- P F Mixter
- Department of Microbiology and Immunology, UCLA School of Medicine
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