scholarly journals Molecular Evolution of Large Virulence Plasmid inShigella Clones and EnteroinvasiveEscherichia coli

2001 ◽  
Vol 69 (10) ◽  
pp. 6303-6309 ◽  
Author(s):  
Ruiting Lan ◽  
Brad Lumb ◽  
David Ryan ◽  
Peter R. Reeves
Keyword(s):  
Escherichia Coli ◽  
Molecular Evolution ◽  
Phylogenetic Relationships ◽  
Shigella Flexneri ◽  
The Other ◽  
Lateral Transfer ◽  
Virulence Plasmid ◽  
Main Body ◽  
Chromosomal Genes ◽  
Cluster 2

ABSTRACT Three genes, ipgD, mxiC, and mxiA,all in the invasion region of the Shigella virulence plasmid, were sequenced from strains representing a range ofShigella serotypes and from two enteroinvasiveEscherichia coli (EIEC) isolates. The plasmids can be classified into two relatively homogeneous sequence forms which are quite distinct. pINV A plasmids are found in Shigella flexneri strains F6 and F6A, S. boydii strains B1, B4, B9, B10, B14, and B15, S. dysenteriae strains D3, D4, D6, D8, D9, D10, and D13, and the two EIEC strains (M519 and M520). pINV B plasmids are present in S. flexneristrains F1A, F2A, F3A, F3C, F4A, and FY, two S. boydiistrains (B11 and B12), and S. sonnei. The D1 pINV plasmid is a recombinant with ipgD gene more closely related to those of pINV A but with mxiA andmxiC genes more closely related to those of pINV B. The phylogenetic relationships of the plasmid and those of the chromosomal genes of Shigella strains are largely consistent. The cluster 1 and cluster 3 strains tested (G.M. Pupo, R. Lan, and P. R. Reeves, Proc. Natl. Acad. Sci. USA 97:10567–10572, 2000) have pINV A and pINV B plasmids, respectively. However, of the three cluster 2 strains (B9, B11, and B15), B9 and B15 have pINV A while B11 has a pINV B plasmid. Those Shigella (D8 and D10 and S. sonnei) and EIEC strains which do not group with the main body of Shigella strains based on chromosomal genes were found to have plasmids belonging to one or the other of the two types and must have acquired these by lateral transfer.

scholarly journals Alterations in the pathogenicity of Escherichia coli K-12 after transfer of plasmid and chromosomal genes from Shigella flexneri.

1983 ◽  
Vol 39 (3) ◽  
pp. 1392-1402 ◽  
Author(s):  
P J Sansonetti ◽  
T L Hale ◽  
G J Dammin ◽  
C Kapfer ◽  
H H Collins ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shigella Flexneri ◽  
Chromosomal Genes ◽  
K 12

scholarly journals Randomly Amplified Polymorphic DNA Analysis in the Genus Hosta

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1243-1245 ◽  
Author(s):  
Roger J. Sauve ◽  
Suping Zhou ◽  
Yingchun Yu ◽  
Wolfram George Schmid
Keyword(s):  
Phylogenetic Relationships ◽  
Genetic Similarity ◽  
Rapd Markers ◽  
Dna Analysis ◽  
The Other ◽  
Randomly Amplified Polymorphic Dna ◽  
Genetic Traits ◽  
Phylogenetic Clustering ◽  
Single Primer ◽  
Cluster 2

A randomly amplified polymorphic DNA (RAPD) technique was used to identify and determine the phylogenetic relationships of 37 hosta accessions representing the major subgenera, sections and groups in the genus Hosta. Results of this study show that RAPD markers were able to differentiate not only the main groups, whose plants shared many genetic traits, but also cultivars within a species. Some accessions were identified by a single primer while others had high intercross linkage and required many markers for their separation. The phylogenetic clustering showed that H. plantaginea, the only night-blooming species, and H. ventricosa, the only known natural tetraploid, are unique and should be classified separately. The four species in the subgenus Bryocles, section Lamellatae H. venusta, H. minor, H. capitata, and H. nakaiana have very low genetic similarity since they do not share many amplified fragments. The other accessions were classified into four main clusters; cluster 1: H. venusta, H. tardiva, H. pycnophylla, H. tsushimensis `Ogon', H. montana, H. tibae, H. montana f. macrophylla, H. kikutii `Kikutii', H. longissima `Longifolia', H. rectifolia `Rectifolia', H. takahashii and H.`Undulata'; cluster 2: H. laevigata, H. sieboldiana, H. pycnophylla × H. longipes f. latifolia, H. longipes `Urajiro' and H. ibukiensis; cluster 3: H. capitata, H. kikutii `Polyneuron', H. nigrescens, H. kikutii `Yakusimensis', H. pachyscapa, H. kikutii `Caput-Avis', H. longipes f. latifolia, H. hypoleuca, H. okamotoi, H. densa and H. takiensis; and cluster 4: H. aequinoctiiantha, H. rupifraga, H. `Amanuma', H. minor and H. kikutii `Densa'.

scholarly journals The Virulence Plasmid-Encoded impCAB Operon Enhances Survival and Induced Mutagenesis in Shigella flexneriafter Exposure to UV Radiation

1999 ◽  
Vol 67 (3) ◽  
pp. 1415-1423 ◽  
Author(s):  
Laura J. Runyen-Janecky ◽  
Mei Hong ◽  
Shelley M. Payne
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Nucleotide Sequence ◽  
Uv Radiation ◽  
Uv Irradiation ◽  
Shigella Flexneri ◽  
Virulence Plasmid ◽  
Repair System ◽  
Induced Mutagenesis ◽  
Dna Fragment

ABSTRACT Upon exposure to UV radiation, Shigella flexneri SA100 displayed survival and mutation frequencies comparable to those ofEscherichia coli AB1157, which contains a functional UmuDC error-prone DNA repair system. Survival of SA100 after UV irradiation was associated with the presence of the 220-kb virulence plasmid, pVP. This plasmid encodes homologues of ImpA and ImpB, which comprise an error-prone DNA repair system encoded on plasmid TP110 that was initially identified in Salmonella typhimurium, and ImpC, encoded upstream of ImpA and ImpB. Although the impBgene was present in representatives of all four species ofShigella, not all isolates tested contained the gene.Shigella isolates that lacked impB were more sensitive to UV radiation than isolates that containedimpB. The nucleotide sequence of a 2.4-kb DNA fragment containing the imp operon from S. flexneri SA100 pVP was 96% identical to the impoperon from the plasmid TP110. An SA100 derivative with a mutation in the impB gene had reduced survival following UV irradiation and less UV-induced mutagenesis relative to the parental strain. We also found that S. flexneri contained a chromosomally encoded umuDC operon; however, theumuDC promoter was not induced by exposure to UV radiation. This suggests that the imp operon but not theumuDC operon contributes to survival and induced mutagenesis in S. flexneri following exposure to UV radiation.

scholarly journals Flanking and Internal Regions of Chromosomal Genes Mediating Aerobactin Iron Uptake Systems in Enteroinvasive Escherichia coli and Shigella flexneri

Microbiology ◽  
1987 ◽  
Vol 133 (8) ◽  
pp. 2269-2278 ◽  
Author(s):  
C. L. MAROLDA ◽  
M. A. VALVANO ◽  
K. M. LAWLOR ◽  
S. M. PAYNE ◽  
J. H. CROSA
Keyword(s):  
Escherichia Coli ◽  
Iron Uptake ◽  
Shigella Flexneri ◽  
Chromosomal Genes

scholarly journals Occurrence of shigatoxinogenic Escherichia coli O157 in Norwegian cattle herds

1998 ◽  
Vol 120 (1) ◽  
pp. 21-28 ◽  
Author(s):  
L. VOLD ◽  
B. KLUNGSETH JOHANSEN ◽  
H. KRUSE ◽  
E. SKJERVE ◽  
Y. WASTESON
Keyword(s):  
Escherichia Coli ◽  
Vero Cell ◽  
Immunomagnetic Separation ◽  
The Other ◽  
Virulence Plasmid ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Faecal Samples ◽  
Cattle Herds ◽  
Encoding Genes

To investigate if there is a reservoir of Escherichia coli O157 in Norwegian cattle, faecal samples from 197 cattle herds were screened for E. coli O157 by the use of immunomagnetic separation (IMS) and PCR during the 1995 grazing season. Six E. coli O157[ratio ]H-isolates were detected in two herds, one isolate in one and five in the other. The isolates carried the stx1, stx2, and eae genes, and a 90 MDa virulence plasmid. They were toxinogenic in a Vero cell assay. From 57 other herds, 137 faecal samples were positive for stx1 and/or stx2 genes detected by PCR run directly on IMS-isolated material. Among these samples, stx2 were the most widely distributed toxin encoding genes. No difference was found among milking cows and heifers in the rate of stx1 and/or stx2 in positive samples.

scholarly journals Establishment of Unipolar Localization of IcsA in Shigella flexneri 2a Is Not Dependent on Virulence Plasmid Determinants

1999 ◽  
Vol 67 (1) ◽  
pp. 350-356 ◽  
Author(s):  
Robin C. Sandlin ◽  
Anthony T. Maurelli
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Bacterial Cell ◽  
Shigella Flexneri ◽  
Virulence Plasmid ◽  
Wild Type ◽  
Common Pathway ◽  
Plasmid Copy ◽  
E Coli ◽  
Shigella Flexneri 2A

ABSTRACT Unipolar localization of IcsA on the surface of Shigella flexneri is required for efficient formation of actin tails and protrusions in infected eucaryotic cells. Lipopolysaccharide (LPS) mutations have been demonstrated to affect either the establishment or the maintenance of IcsA in a unipolar location, although the mechanism is unknown. In order to analyze the contribution of virulence plasmid determinants on the unipolar localization of IcsA, we examined the localization of IcsA expressed from a cloned plasmid copy in two different genetic backgrounds. The localization of IcsA was first examined in a virulence plasmid-cured derivative of the wild-typeS. flexneri 2a isolate 2457T. This approach examined the contribution of virulence plasmid-borne factors, including the previously identified virulence plasmid-borne protease that is responsible for cleaving IcsA in the outer membrane and releasing the 95-kDa secreted form from the cell surface. IcsA localization in a related but nonpathogenic Escherichia coli strain expressing LPS of the O8 serotype was also examined. IcsA surface presentation in both of these genetic backgrounds continued to be unipolar, demonstrating that virulence plasmid-borne determinants are not responsible for unipolar localization of IcsA. The unipolar localization of IcsA in the E. coli background suggests that a common pathway that allows IcsA to be spatially restricted to one pole on the bacterial cell surface exists in Shigellaand E. coli.

scholarly journals Expression of the Virulence Plasmid-Carried Apyrase Gene (apy) of Enteroinvasive Escherichia coli andShigella flexneri Is under the Control of H-NS and the VirF and VirB Regulatory Cascade

1998 ◽  
Vol 66 (10) ◽  
pp. 4957-4964 ◽  
Author(s):  
Francesca Berlutti ◽  
Mariassunta Casalino ◽  
Carlo Zagaglia ◽  
Piera Assunta Fradiani ◽  
Paolo Visca ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Regulatory Network ◽  
Shigella Flexneri ◽  
Pcr Analysis ◽  
Virulence Plasmid ◽  
Wild Type ◽  
Molecular Alterations ◽  
Regulatory Cascade ◽  
Severe Reduction ◽  
Red Dye

ABSTRACT The transcription of the virulence plasmid (pINV)-carried invasion genes of Shigella flexneri and enteroinvasiveEscherichia coli (EIEC) is induced at 37°C and repressed at 30°C. In this work, we report that the O135: K−:H− EIEC strain HN280 and S. flexneri SFZM53, M90T, and 454, of serotypes 4, 5, and 2a, respectively, produce apyrase (ATP-diphosphohydrolase), the product of the apy gene. In addition, the S. flexneri strains, but not the EIEC strain, produce a nonspecific phosphatase encoded by the phoN-Sfgene. Both apy and phoN-Sf are pINV-carried loci whose contribution to the pathogenicity of enteroinvasive microorganisms has been hypothesized but not yet established. We found that, like that of virulence genes, the expression of both theapy and the phoN-Sf genes was temperature regulated. Strain HN280/32 (a pINV-integrated avirulent derivative of HN280 which has a severe reduction of virB transcription) expressed the apy gene in a temperature-regulated fashion but to a much lower extent than wild-type HN280, while the introduction of the Δhns deletion in HN280 and in HN280/32 induced the wild-type temperature-independent expression of apyrase. These results indicated that a reduction of virB transcription, which is known to occur in the pINV-integrated strain HN280/32, accounts for reduced apyrase expression and that the histone-like protein H-NS is involved in this regulatory network. Independent spontaneously generated mutants of HN280 and of SFZM53 which had lost the capacity to bind Congo red dye (Crb−) were isolated, and the molecular alterations of pINV were evaluated by PCR analysis. Alterations of pINV characterized by the absence of virF or virBand by the presence of the intact apy locus or intactapy and phoN-Sf loci were detected among Crb− mutants of HN280 and SFZM53, respectively. While all Crb− apy + mutants of HN280 failed to produce apyrase, Crb− apy+phoN-Sf + mutants of SFZM53 lacked apyrase activity but produced a nonspecific phosphatase, like parental SFZM53. Moreover, the introduction of recombinant plasmids carrying clonedvirF (pMYSH6504) or virB (pBN1) into Crb− mutants of HN280 and SFZM53 lacking virFor virB, respectively, fully restored temperature-dependent apyrase expression to levels resembling those of the parental strains. Taken together, our results demonstrate that, as has already been shown for invasion genes, apy is another locus whose expression is controlled by temperature, H-NS, and the VirF and VirB regulatory cascade. In contrast, the temperature-regulated expression of the nonspecific phosphatase does not appear to be under the control of the same regulatory network. These findings led us to speculate that apyrase may play a role in the pathogenicity of enteroinvasive bacteria.

Infection of Escherichia coli with bacteriophages

1969 ◽  
Vol 27 ◽  
pp. 370-371
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acid ◽  
Cell Surface ◽  
Virus Type ◽  
Infection Process ◽  
Adsorption Site ◽  
The Other ◽  
Specific Receptors ◽  
Bacterial Receptors

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.

The Nature of the Intramembrane Particle

1980 ◽  
Vol 38 ◽  
pp. 688-691
Author(s):  
A.J. Verkleij
Keyword(s):  
Escherichia Coli ◽  
Tight Junction ◽  
Gap Junction ◽  
The Other ◽  
Fracture Face ◽  
Band 3 Protein ◽  
Satisfactory Explanation ◽  
Freeze Fracturing ◽  
Intramembrane Particle ◽  
Luminal Membrane

Freeze-fracturing splits membranes into two helves, thus allowing an examination of the membrane interior. The 5-10 rm particles visible on both monolayers are widely assumed to be proteinaceous in nature. Most membranes do not reveal impressions complementary to particles on the opposite fracture face, if the membranes are fractured under conditions without etching. Even if it is considered that shadowing, contamination or fracturing itself might obscure complementary pits', there is no satisfactory explanation why under similar physical circimstances matching halves of other membranes can be visualized. A prominent example of uncomplementarity is found in the erythrocyte manbrane. It is wall established that band 3 protein and possibly glycophorin represents these nonccmplanentary particles. On the other hand a number of membrane types show pits opposite the particles. Scme well known examples are the ";gap junction',"; tight junction, the luminal membrane of the bladder epithelial cells and the outer membrane of Escherichia coli.

scholarly journals Lac Operon Boolean Models: Dynamical Robustness and Alternative Improvements

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 600 ◽  
Author(s):  
Marco Montalva-Medel ◽  
Thomas Ledger ◽  
Gonzalo A. Ruz ◽  
Eric Goles
Keyword(s):  
Escherichia Coli ◽  
Limit Cycles ◽  
The Other ◽  
Lac Operon ◽  
Boolean Models ◽  
Bistable Behavior

In Veliz-Cuba and Stigler 2011, Boolean models were proposed for the lac operon in Escherichia coli capable of reproducing the operon being OFF, ON and bistable for three (low, medium and high) and two (low and high) parameters, representing the concentration ranges of lactose and glucose, respectively. Of these 6 possible combinations of parameters, 5 produce results that match with the biological experiments of Ozbudak et al., 2004. In the remaining one, the models predict the operon being OFF while biological experiments show a bistable behavior. In this paper, we first explore the robustness of two such models in the sense of how much its attractors change against any deterministic update schedule. We prove mathematically that, in cases where there is no bistability, all the dynamics in both models lack limit cycles while, when bistability appears, one model presents 30% of its dynamics with limit cycles while the other only 23%. Secondly, we propose two alternative improvements consisting of biologically supported modifications; one in which both models match with Ozbudak et al., 2004 in all 6 combinations of parameters and, the other one, where we increase the number of parameters to 9, matching in all these cases with the biological experiments of Ozbudak et al., 2004.

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