03 μg/ml), using b 0.5%, c 1% or d 2% suspensions of SRBC. The results are the average of P-gp inhibitor three independent experiments, each performed in triplicate ± the standard deviation. Asterisks indicate significant differences according to Student’s t test (*, P < 0.05; **, P < 0.01). Analysis of trapped chromosomal DNA fragments in Selleckchem Liproxstatin 1 strains showing penicillin G-inducible
hly expression The chromosomal fragments carrying penicillin G-inducible promoters were sequenced and compared with the L. monocytogenes EGD-e genome. In the case of seven strains, namely 15, 18, 37, 198, 199, 201 and 203 (Table 2), this analysis identified single genes as the source of the trapped chromosomal DNA fragments. In PF-573228 research buy the case of strain 195, the
trapped fragment was comprised of sequences originating from two genes, lmo2095 and lmo2096, both present in the opposite transcriptional orientation to the reporter gene. It was reasoned that the identified promoter might originate from a divergently transcribed gene positioned immediately upstream of the cloned fragment, but examination of the genome sequence showed that the two preceding genes, lmo2097 and lmo2098, are in the same orientation as lmo2095 and lmo2096. Thus, the identified promoter could not direct the expression of any of these genes and for this reason it
was excluded from further investigations. In the case of strain 41, the trapped chromosomal fragment contained the full sequence of genes lmo0943 (fri) and lmo0944 plus sequences upstream of these genes, as well as a fragment of the sequence preceding gene lmo0945, which is in the same Thiamet G transcriptional orientation. Thus, on the basis of simple sequence analysis it was not possible to identify which promoter was directing hly expression in this strain. In an attempt to clarify this situation, the possible cotranscription of fri, lmo0944 and lmo0945 was examined by RT-PCR. The three anticipated PCR products were amplified from cDNA generated by reverse transcription using primers specific for genes lmo0945 and lmo0944, which demonstrated that fri, lmo0944 and lmo0945 are cotranscribed in both non-stressed cells and in cells grown under penicillin G pressure (Figure 1). Consequently, each of these genes was analyzed further. Table 2 Description of L. .