Growth on ManNAc caused a significant increase of transcriptional levels of all genes analysed (Figure 3D). The values of mean fold changes were 17.61 (p < 0.01) for nanA, 52.18 (p < 0.01) for SPG1598, 6.33 (p < 0.05) for SPG1592 and 6.65 (p < 0.05) for satC SPG1591. Figure 3 Growth and induction of gene expression by ManNAc. (A)

Growth of S. pneumoniae strains on CAT medium supplemented with 10 g/L of ManNAc: FP65 (open squares), nanAB-deficient mutant (open triangles), and SPG1583-regulator deletion mutant (closed circles). (B) Growth of FP65 on CAT medium without added sugar learn more (closed squares) and supplemented with ManNAc 10 g/L (open squares). The white and black arrows indicate samples taken for quantitative Real Time-PCR. Gene expression analysis of the genes coding for NanA the ABC transporter SPG1598, the PTS transporter SPG1592, and the ABC transporter

SPG1591 is shown in panel C and D. Panel C refers to fold changes in transcriptional levels at OD 0.02 in medium with or without ManNAc (for sampling see closed arrows in panel 3B). Panel D refers to analysis of sequential samples (OD590 = 0.02 and OD590 = 0.05) of bacteria grown in ManNAc (for sampling see open arrows in panel 3B). The fold changes are reported as mean from independent triplicate or quadruplicate experiments. Two-tailed Student t test was used for analyse statistical AZD1480 in vitro significance (*, p < 0.05; **, p < 0.01). Generation time on unsuplemented CAT medium is 40 min and on

ManNAc 140 min. To evaluate the role of glucose and of the two amino sugars ManNAc and NeuNAc in the regulation of the nanAB regulon, we quantify gene expression see more during growth in the presence of these sugars. Bacteria were grown in the presence of ManNAc (Figure 4A, open triangles) or NeuNAc (Figure 4B, open triangles) and their gene expression was compared to that of bacteria grown with 1 g/L glucose alone (Figure 4A,B, closed enough circles). All genes of the nanAB regulon showed a significant increase in transcription in presence of any of the amino sugars. The values of mean fold changes were: nanA, 2.69 (p ≤ 0.05) in ManNAc and 5.14 (p ≤ 0.05) in NeuNAc; SPG1598, 3.35 (p ≤ 0.05) in ManNAc and 1.99 in NeuNAc; SPG1592, 3.21 (p ≤ 0.05) in ManNAc and 3.74 (p ≤ 0.05) in NeuNAc; SPG1591, 3.45 (p ≤ 0.05) in ManNAc and 5.13 (p ≤ 0.01) in NeuNAc. Interestingly the transporter SPG1596-8 linked to the growth and fermentation of ManNAc was more induced by this sugar, while NeuNAc had a significantly greater effect on the satABC SPG1589-91 transporter, again in accordance with phenotypic data. Figure 4 Repression of nanAB locus by glucose. (A) Growth curves of FP65 in medium supplemented with glucose (closed circles), ManNAc (open triangles), and glucose plus ManNAc (open squares).