IGEM:Caltech/2008/Project/ROS

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iGEM 2008

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Conjugation Can get conjugation from Salmonella to E. coli [1] Papers seem to assume that conjugation is quick, and maintenance is the hard part (unless we engineer a shuttle vector). Doesn't address specificity, though. "Conjugation of S. typhi with E. coli F+ carrying P1CM+ gave three types of S. typhi CMr clones: those which carry the whole P1CMphage, those with the PldCM element, and those with nontransferable CMr."[2] Can get transfer of an F' plasmid from E. coli to Salmonella[3] Doug Tischer 21:12, 26 May 2008 (EDT)There exists a plasmid (pAT187) that can be transfered from E. coli to a wide range of gram-positive bacteria [4] Doug Tischer 17:42, 27 May 2008 (EDT)Surface exclusion seems to be the name given to the process that prevents a bacteria containing a plasmid from conjugating and receiving the same plasmid again. In F plasmid, the are the traS and traT genes. traT inhibits the formation of mating aggregates. [5] Specificity Could we detect transmission of the Salmonella virulence plasmid? "The second experiment was to physically observe the transferred virulence plasmid in the recipient strain.... Therefore, E. coli was chosen to be the recipient in matings with Salmonella.... Transconjugants were obtained at a frequency of approximately 2 × 10−5 transconjugants/donor.... Ethidium bromide staining of the pulsed-field gel shows that the restriction pattern of the transconjugant genomes matches that of the E. coli recipient, except for the acquisition of the virulence plasmid from the Salmonella donor. The identity of the virulence plasmid was confirmed by subsequent Southern hybridization with the kanamycin resistance gene of MudJ.... This is clear evidence that conjugation has occurred."[6] sdiA transcription factor? [7] Or spvR[8, 9]. It functions in E. coli and is necessary for virulence. So our bacteria are floating around waiting for conjugation from a pathogenic Salmonella. Once that happens, a spvR promoter turns on, triggering the ROS. The low conjugation frequency is troubling. However, some of that might be low efficiency genomic integration. References Makanera A, Arlet G, Gautier V, and Manai M. Molecular epidemiology and characterization of plasmid-encoded beta-lactamases produced by Tunisian clinical isolates of Salmonella enterica serotype Mbandaka resistant to broad-spectrum cephalosporins. J Clin Microbiol. 2003 Jul;41(7):2940-5. DOI:10.1128/JCM.41.7.2940-2945.2003 | Kondo E and Mitsuhashi S. Drug resistance of enteric bacteria. VI. Introduction of bacteriophage P1CM into Salmonella typhi and formation of PldCM and F-CM elements. J Bacteriol. 1966 May;91(5):1787-94. DOI:10.1128/jb.91.5.1787-1794.1966 | Lenny AB and Margolin P. Locations of the opp and supX genes of Salmonella typhimurium and Escherichia coli. J Bacteriol. 1980 Aug;143(2):747-52. DOI:10.1128/jb.143.2.747-752.1980 | Mazodier P, Petter R, and Thompson C. Intergeneric conjugation between Escherichia coli and Streptomyces species. J Bacteriol. 1989 Jun;171(6):3583-5. DOI:10.1128/jb.171.6.3583-3585.1989 | Achtman M, Morelli G, and Schwuchow S. Cell-cell interactions in conjugating Escherichia coli: role of F pili and fate of mating aggregates. J Bacteriol. 1978 Sep;135(3):1053-61. DOI:10.1128/jb.135.3.1053-1061.1978 | Ahmer BM, Tran M, and Heffron F. The virulence plasmid of Salmonella typhimurium is self-transmissible. J Bacteriol. 1999 Feb;181(4):1364-8. DOI:10.1128/JB.181.4.1364-1368.1999 | Ahmer BM, van Reeuwijk J, Timmers CD, Valentine PJ, and Heffron F. Salmonella typhimurium encodes an SdiA homolog, a putative quorum sensor of the LuxR family, that regulates genes on the virulence plasmid. J Bacteriol. 1998 Mar;180(5):1185-93. DOI:10.1128/JB.180.5.1185-1193.1998 | Grob P, Kahn D, and Guiney DG. Mutational characterization of promoter regions recognized by the Salmonella dublin virulence plasmid regulatory protein SpvR. J Bacteriol. 1997 Sep;179(17):5398-406. DOI:10.1128/jb.179.17.5398-5406.1997 | Wilson JA, Doyle TJ, and Gulig PA. Exponential-phase expression of spvA of the Salmonella typhimurium virulence plasmid: induction in intracellular salts medium and intracellularly in mice and cultured mammalian cells. Microbiology (Reading). 1997 Dec;143 ( Pt 12):3827-3839. DOI:10.1099/00221287-143-12-3827 | Plainkum P, Fuchs SM, Wiyakrutta S, and Raines RT. Creation of a zymogen. Nat Struct Biol. 2003 Feb;10(2):115-9. DOI:10.1038/nsb884 | Firbank SJ, Rogers MS, Wilmot CM, Dooley DM, Halcrow MA, Knowles PF, McPherson MJ, and Phillips SE. Crystal structure of the precursor of galactose oxidase: an unusual self-processing enzyme. Proc Natl Acad Sci U S A. 2001 Nov 6;98(23):12932-7. DOI:10.1073/pnas.231463798 | Sun L, Petrounia IP, Yagasaki M, Bandara G, and Arnold FH. Expression and stabilization of galactose oxidase in Escherichia coli by directed evolution. Protein Eng. 2001 Sep;14(9):699-704. DOI:10.1093/protein/14.9.699 | Uehara Y, Kikuchi K, Nakamura T, Nakama H, Agematsu K, Kawakami Y, Maruchi N, and Totsuka K. H(2)O(2) produced by viridans group streptococci may contribute to inhibition of methicillin-resistant Staphylococcus aureus colonization of oral cavities in newborns. Clin Infect Dis. 2001 May 15;32(10):1408-13. DOI:10.1086/320179 | Toomey D and Mayhew SG. Purification and characterisation of NADH oxidase from Thermus aquaticus YT-1 and evidence that it functions in a peroxide-reduction system. Eur J Biochem. 1998 Feb 1;251(3):935-45. DOI:10.1046/j.1432-1327.1998.2510935.x | Whittaker JW. The radical chemistry of galactose oxidase. Arch Biochem Biophys. 2005 Jan 1;433(1):227-39. DOI:10.1016/j.abb.2004.08.034 |