Basic Research
Copyright ©The Author(s) 2003.
World J Gastroenterol. Dec 15, 2003; 9(12): 2720-2725
Published online Dec 15, 2003. doi: 10.3748/wjg.v9.i12.2720
Table 1 Strains and plasmids
Strains and plasmidsCharacteristicsSource (reference)
Strains
DH5αendA1 hsdR17(rk-mk+) supE44 thi-1 recA1 gyrA(Nalr)Our lab
RelA1 △ lacIZYA-argF) U169 deoR (φ80dlac △(lacZ)M15)
S17-1λpirthi-1 thr leu tonA lacY supE recA::RP4-2-Tc::Mu, Smr, λpirGuzman CA
MC1061hsdR2 mcrB araD139 △ (ara ABC-leu)7679 △ lacX74 galU galK rpsL thi, SmrOur lab
2457TS. flexneri 2a wild type, NalrMaurelli AT
2457T05a derivative strain of 2457T, contained araBp-gam-bet-exo, NalrThis study
2457T028D△ alkA, derivative strain of 2457T, Nalr, KmrThis study
Plasmids
pMD18-Ta derivative constructed from pUC18, AprTaKaRa
pXL275a mobile and suicide plasmid, ori R6K, mob RK2, sacBR, CmrRui et al[17]
pKD46oriR101, repA101(ts), araBp-gam-bet-exo, AprCGSCa
pXLkd46pXL275 derivative, inserted a fragment containing araBp-gam-bet-exo, CmrThis study
pMDKm05pMD18-T derivative, inserted Kmr gene, Kmr, AprOur lab
pMD028pMD18-T derivative, inserted alkA gene, AprThis study
pMD028pKmpMD18-T derivative, inserted a cassette (5’alkA end-Kmr-3’alkA end), Kmr, AprThis study
Table 2 BLAST analysis of S. flexneri 2a alkA gene
BacteriaGene productGene functionIdentities (%)
Escherichia coli K123-methyl-adenine DNA glycosylase IIDNA - replication, repair, restriction/modification97%
Escherichia coli O157:H73-methyl-adenine DNA glycosylase IIMacromolecule synthesis, modification: DNA - replication, repair, restriction/modification97%
Salmonella typhimurium3-methyl-adenine DNA glycosylase IIUnknown74%
Ralstonia solanacearumputative transcription regulator proteinMiscellaneous; not classified regulator38%
Pseudomonas aeruginosaDNA-3-methyladenine glycosidase IIUnknown37%
Xanthomonas axonopodisDNA methylation and regulatory proteinUnknown35%
Mycobacterium bovisMethylated-DNA—protein-cysteine methyltransferaseAdaptative response34%
Mycobacterium tuberculosisalkA proteinUnknown34%
Vibrio choleraeada regulatory proteinUnknown32%
Bacillus anthracisDNA-3-methyladenine glycosidaseUnknown32%
Archaeoglobus fulgidus3-methyladenine DNA glycosylaseDNA repair at suboptimal and maybe even mesophilic temperatures30%
Table 3 Competitive analysis of different strains of S. flexneri 2a
StrainsCompetitive index (CI)a
BALB/c mouse infectionHeLa cells infection
2457T050.96 ± 0.271.07 ± 0.35
2457T028D0.21 ± 0.09b0.25 ± 0.11b
MC10610.03 ± 0.02b0.02 ± 0.01b