8S rRNA gene-ITS2 sequences and are depicted in Table 2. Characterized by multiple nt-insertion events, up to 21 (see File S1), the sequences of the P. puniceus strains are not reported on this table. This sequence specificity was further confirmed by clustering ITS sequences available on GenBank (accession numbers FJ372685 and FJ372686) from Thai strains of P. puniceus. C and T insertions (at positions 48 and 452, respectively), and C at position 126 (instead of T) were shown to Erastin mouse be

specific to the P. cinnabarinus species. All the strains of P. sanguineus from Madagascar, Vietnam, French Guiana, New Caledonia and Venezuela exhibited identical ITS1 and ITS2 sequences. A common T/G and A/C substitution (at positions 43 and 113) was observed for the Chinese strains of P. sanguineus, including CIRM-BRFM 542 of unknown origin, and for all strains of P. coccineus. T/C and C/T substitutions (at positions 323 and 333) were shown to be specific to the East Asian strains of P. sanguineus and P. coccineus. Likewise, the ITS1 and ITS2 sequences of the strain MUCL 38420 (from Australia) classified as P. cinnabarinus were identical to those of both P. coccineus strains

from Australia (MUCL 38523 and MUCL 38525), strongly suggesting taxonomic misidentification of the specimen. The strain MUCL 38420 was collected in Australia at the beginning of the 20th century; at that time, Talazoparib in vivo P. coccineus had not yet been described (Ryvarden & Johansen, 1980). In addition, the species P. cinnabarinus is known to be especially distributed in the temperate northern regions (Nobles & Frew, 1962). Amplification of β-tubulin encoding gene fragments yielded 400-bp products on average. Comparison between gene and predicted cDNA fragment sequences showed that the corresponding coding region was interrupted by one intron. Interestingly, the intron length was 53, 54, 55 and

59 bp respectively for the species P. puniceus, P. cinnabarinus, P. sanguineus and P. coccineus, except for the Chinese P. sanguineus strains (including CIRM-BRFM 542), for which intron length was similar to that of P. coccineus species (59 bp instead of 55 bp). Identity between the ID-8 partial predicted cDNAs was 78% on average. However, the amino acid sequences of the deduced partial proteins were 100% similar for all the strains. β-Tubulin-encoding gene fragments, sequenced for the first time in Pycnoporus strains, were aligned in 263 nucleotide positions, and 55 of them (21%) varied among the strains of Pycnoporus (see File S2). The partial alignment depicted in Table 3 shows the most informative nucleotide sites, 26 in all. Compared with all the P. coccineus and P. sanguineus strains, specific variations occurred in six positions for the strains of P. puniceus and nine positions for the strains of P. cinnabarinus. Among the P. sanguineus and P. coccineus strains, sequence identities were observed for the strains of P.

coli CC118λpir (Manoil & Beckwith, 1985). After verification by sequencing, they were transferred to E. coli SM10λpir (Miller & Mekalanos, 1988) for mating. EDL933 NalR (spontaneous mutation) and the respective SM10λpir plus the modified pMRS101 were mixed and plated on LB-agar (24 h, 30 °C). Cells were resuspended again and plated on LB-agar with 30 μg mL−1 streptomycin and 20 μg mL−1 nalidic acid. Correct plasmid integration after a first cross-over was checked by PCR. Second cross-over

events, resulting in plasmid loss, either restore wild type or create the mutation. Thus, bacteria were grown without selection to OD600 nm = 0.8 and plated on LB-agar without Selleck Daporinad NaCl plus 10% sucrose for sacB-counter

selection. Desired mutants were identified using PCR. Biofilm experiments were conducted according to Domka et al. (2007). A culture grown in M9 minimal medium (Sambrook & Russel 2001) was diluted to OD600 nm = 0.05. Flat-bottom wells of a microtiter plate (Greiner Bio One, Germany) were filled with 100 μL and incubated 24 or 48 h without shaking at 30 °C or 37 °C. OD600 nm was measured (Victor3). The planktonic cells were removed, and each well was carefully washed with water. Staining was achieved using 135 μL 0.1% crystal violet (20 min, RT). After washing thrice with water and air drying, the stain was solubilized in 95% ethanol, transferred to a new plate and the absorbance at 600 nm was measured Navitoclax datasheet (Victor3). The mean was calculated (10 wells, three biological replicates) after

subtracting zero controls (medium only). Amplicons of htgA and yaaW were cloned into pBAD/Myc-His C (Invitrogen). EHEC with plasmids (sequenced for verification) were grown in LB with 100 μg mL−1 ampicillin and induced with 0.2% arabinose. Proteins were purified according to QIAexpress® Ni-NTA Fast-Start kit under denaturing conditions (Qiagen). For this, the bacteria were sonicated in the provided lysis buffer. For SDS-PAGE (15%), Laemmli-buffer was added, and the sample denatured for 5 min at 95 °C. PageRuler Protein Ladder (Fermentas) was used as marker. After electrophoresis, selleck chemicals llc the proteins were electroblotted (20 min, 120 mA) to an activated PVDF membrane (Amersham). Subsequently, the membrane was blocked, incubated with mouse-anti-human c-myc-antibodies (BD Biosciences), washed, incubated with alkaline phosphatase anti-mouse chimera antibodies (Dianova, Hamburg), washed again, equilibrated and incubated in buffer supplemented with BCIP/NBT. Metabolites were profiled using Ion cyclotron resonance Fourier transform Mass spectrometry (ICR-FT/MS) on a Bruker solariX with a 12-T magnet (Bruker Daltonics, Bremen). Three biological replicate cultures of wild type, ΔhtgA, and ΔyaaW were grown shaking in 1 : 2-diluted LB to OD600 nm = 1. Cultures were vacuum filtered using HVLP filters (0.45 μm; Millipore).

, 2001). KirP contains all three conserved sequence motifs described by Lambalot et al. (1996) and Sanchez et al. (2001). Based on the presence of a conserved FSxKESLxK in motif P3 and its phylogenetic relationship to other PPTases, KirP can be assigned to the F/KES subfamily (Copp & Neilan, 2006) of Sfp-type PPTases. To analyze the role of KirP in vivo, kirP was inactivated by gene replacement. The gene replacement plasmid pEP10 was introduced into the wild-type strain S. collinus Tü 365. Homologous recombination resulted in the replacement of kirP with the thiostrepton resistance cassette of pEP10. The genotype of the resulting mutant strain, EP-P1, was confirmed

by Southern analysis with a kirP probe (Fig. 1a and b). Extracts from wild-type Epacadostat and EP-P1 cultures

were analyzed for kirromycin production by HPLC. The mutant strain showed a substantial reduction in kirromycin yield of approximately 90%. The identity of kirromycin was confirmed by comparison with an HPLC-UV/Vis spectra library (Fiedler, 1993) and by MS (m/z of kirromycin=795 [M-H]−). To prove that PD0332991 datasheet the significant reduction in kirromycin yield is due to the inactivation of kirP, plasmid pEP11 expressing the intact wild-type kirP gene under control of the consitutive ermE* promoter was used to complement the inactivated kirP gene. The pEP11 construct was introduced into the mutant strain EP-P1. In the complemented strain, kirromycin production was partially restored, increasing by a factor of 3 compared with the mutant and reaching approximately 30% of the wild-type production level. Observations that gene replacement mutations in streptomycetes can

be only partially complemented have been made in many pathways, for example daptomycin biosynthesis (Coeffet-Le Gal et al., 2006) when genes are deleted and subsequently reintroduced in a different context (for a review, also see Baltz, 1998). The partial complementation of the kirP deletion in mutant EP-P1 indicated that MYO10 the loss of kirP activity was responsible for the large decrease in kirromycin production and thus that kirP plays an important role in the biosynthesis of kirromycin. However, the kirP gene replacement mutant was viable and produced low amounts of kirromycin. This finding implies that the genome of the producer strain S. collinus Tü 365 includes additional PPTase genes. Indeed, analysis of preliminary data of an ongoing whole genome sequencing project of S. collinus enabled the identification of at least six additional Sfp-type PPTase genes and one ACPS-type PPTase gene in the genome of the kirromycin producer strain. Thus, one or more of these enzymes might provide some phosphopantetheinylation of the kirromycin PKS/NRPS enzyme, albeit with a much lower efficiency than KirP, as indicated by the 90% drop in kirromycin yield in the kirP deletion mutant EP-P1.

(2005) identified mutations in the atpE gene leading to diarylquinone resistance in Mycobacterium tuberculosis and Mycobacterium smegmatis. By whole-genome sequencing, base substitutions suppressing relA mutations were identified (Srivatsan et al., 2008). In B. subtilis, a point mutation in the yqiD gene generated one type of l-form (Leaver et al., 2009). Makarov et al. (2009) identified the arabinan pathway as a target for benzothiazinones in M. tuberculosis. Here, we report the molecular basis for a mechanism circumventing the action of the BIBF 1120 in vitro new antibiotic CmC on B. subtilis. Taq, Taq native

and Pvu DNA polymerases were purchased from Fermentas. DNase I and SuperScript™III reverse transcriptase were from Ambion and Invitrogene, respectively. Escherichia coli strains DH5α and TG1 and B. subtilis strain 168 were used and grown in Luria–Bertani (LB) medium. According to Steinfels et al. (2004), mutant

B. subtilis 8R was grown in the presence of CmC with or without the addition of 50 μM reserpine. Total RNA was prepared as described (Heidrich et al., 2006). RNA used for real-time PCR was treated with 3 μL DNase I (1 U μL−1) in 50 μL in the presence of 0.5 μL RiboLock™ RNase Inhibitor (40 U μL−1) and DNase I buffer with MgCl2 for 30 min at 37 °C, followed by 10 min at 80 °C to inactivate the enzyme. The RNA was further purified using the DNA-free RNA Kit from Zymo Research. For qRT-PCR, the Applied Biosystems StepOne real-time PCR system and the GeneAmp Fast SYBR Green Master Mix were used. The PCR conditions on the cDNA were optimized in the Applied Biosystems fast cycler ‘Verity’. Ratios were calculated using the check details ΔΔCT method (Pfaffl, 2002). Membrane proteins were prepared using a protocol adapted from Steinfels et al. (2002). Primers pxyvcC-F and yvcC2MF_2 as well as pxyvcC-R1 and primer yvcC2MR_2 were used to generate PCR fragments. After annealing, the resulting

chimera sequences were extended and amplified using primers pxyvcC-F and pxyvcC-R1 to give rise to a long fragment of 1289 bp. Similarly, using primers yvcC1 MF_2 and yvcC1MR_2, a PCR fragment containing only the +6 mutation was generated. These fragments Pregnenolone were used to transform B. subtilis 168 and select for growth in the presence of different CmC concentrations. Preparation of B. subtilis RNAP and in vitro transcription experiments were performed as described previously (Licht et al., 2008). Gels were dried and subjected to Phosphoimaging (Fujix BAS 1000). pc bas 2.0e software was used for the quantification of the bands. Bacillus subtilis 168 grown till the late log-phase was inoculated 1 : 100 in 10 mL LB medium without an antibiotic and LB with 0.25 μM CmC [0.5 × minimal inhibitory concentration (MIC)], with 0.5 μM CmC (1 × MIC) and with 1 μM CmC (2 × MIC) and incubated for 24 h at 37 °C and 200 r.p.m., yielding turbid growth only in the 1 μM CmC culture.

The UK Collaborative

HIV Cohort (CHIC) study was initiated in 2001 and collates routine data on HIV-infected individuals attending some of the largest clinical centres in the UK since 1 January 1996. The project was approved by a Multicentre Research Ethics Committee and by local ethics committees. In accordance with data projection policy, data were provided in a pseudo-anonymized format with all names removed and replaced by first-name initial and a Soundex code derived http://www.selleckchem.com/products/dabrafenib-gsk2118436.html from the patient’s surname. The criteria for inclusion of an individual in the UK CHIC study are that they are HIV-positive, have attended one of the collaborating centres at any time since 1996 and are aged 16 years or over [19]. The analyses are based on data collected up to 31 December 2009. Participants were eligible for analysis if they were antiretroviral-naïve, started cART after 1997, and had at least one CD4 measurement within the baseline period

(90 days before to 6 days after starting cART) and at least one CD4 measurement 6 months after initiation of cART. Participants were further required to have at least one HIV-1 RNA measurement 6 months after initiation of cART and at least one HIV-1 RNA measurement 0–179 days before every CD4 cell count. Virological failure was defined a priori as an HIV-1 RNA measurement exceeding 1000 HIV-1 RNA copies/mL, regardless of whether a participant had interrupted treatment. CD4 cell counts GSK126 were natural log-transformed (zero counts set to 1), to meet assumptions about

stability of the variance with increasing CD4 cell count. The relationship between natural log CD4 cell count and time was modelled as a fractional polynomial; fractional polynomials offer a greater range of curve shapes than linear or quadratic polynomials [20]. Fractional Buspirone HCl polynomials of one and two degrees with powers −2, −1, −0.5, 0, 0.5, 1, 2, 3 were considered (power zero is interpreted as a natural log transformation), including models with repeated powers. We fitted random-effects models with the intercept and fractional polynomial terms random at the individual level, thus allowing CD4 cell count trajectories to vary between individuals. The best-fitting fractional polynomial was selected by comparing the deviance of different models and the percentage of predicted values within 5% of the observed values (see Appendix S1). Participants were classified by their baseline CD4 count (<25, 25–49, 50–99, 100–199, 200–349, 350–499 and ≥500 cells/μL). Participants with more than one CD4 cell count within the baseline period were classified using the measurement closest to the start of cART.

Cataplexy-like episodes were not observed. The percentage time spent in wakefulness and non-REM (NREM)

Dasatinib clinical trial sleep and the power spectral profile of NREM and REM sleep were unaffected. Control animals, injected with scrambled siRNA, had no sleep changes after injection. Quantification of the knockdown revealed that unilateral microinjection of siRNAs targeting OxR1 into the rat LC on two consecutive days induced a 45.5% reduction of OxR1 mRNA in the LC 2 days following the injections when compared with the contralateral side receiving injections of control (scrambled) siRNAs. This reduction disappeared 4 days after injection. Similarly, unilateral injection of OxR1 siRNA into the LC revealed a marked (33.5%) reduction of OxR1 staining 2 days following injections. In contrast, both the mRNA level and immunohistochemical staining for tyrosine hydroxylase were unaffected. The results indicate that a modest knockdown of OxR1 is sufficient to induce observable Cabozantinib purchase sleep changes. Moreover, orexin neurons, by acting on OxR1 in the LC, play a role in the diurnal gating of REM sleep. “
“Stimulation of the vagus nerve produces antiepileptic effects. This is used clinically to treat drug-refractory epilepsies. The mechanisms responsible for these effects depend

on the activation of vagal afferents reaching the nucleus of the solitary tract. This review focuses on the neuroanatomy of the nucleus of the solitary tract and its relation with the nucleus locus coeruleus as a preferential anatomical substrate in producing antiepileptic effects. In fact, following the transient or permanent inactivation of locus coeruleus neurons, some antiepileptic effects of vagus nerve stimulation are lost. The activation of locus coeruleus per se is known to limit the spread of a seizure and the duration of a variety of seizure types. This is due to the fine chemical neuroanatomy of norepinephrine pathways that arise from the locus coeruleus, which produce widespread changes in cortical areas. These

Resveratrol changes may be sustained by norepinephrine alone, or in combination with its co-transmitters. In addition, vagus nerve stimulation may prevent seizures by activating the serotonin-containing dorsal raphe neurons. “
“Potassium channels comprise the most diverse family of ion channels and play critical roles in a large variety of physiological and pathological processes. In addition to their molecular diversity, variations in their distributions and densities on the axo-somato-dendritic surface of neurons are key parameters in determining their functional impact. Despite extensive electrophysiological and anatomical investigations, the exact location and densities of most K+ channels in small subcellular compartments are still unknown.

Therefore, it was assumed that the g-TrepoF primer covers all rumen Treponema and also has a broad coverage of nonruminal Treponema. The specificity of the primer (g-TrepoF) for rumen Treponema was also validated using an online blast similarity search and by PCR amplification of 16 representative rumen bacteria. The blast similarity search of the primer sequences showed similarity with 16S rRNA gene sequences of

spirochetes. The primer set g-TrepoF and BAC926R did not cross-react with any of the nontarget rumen bacteria tested at the specified PCR conditions, while PCR products of the expected size were obtained from T. bryantii genomic DNA (data not shown). The Treponema clone libraries PLX3397 purchase constructed from DNA extracts of rumen digesta of sheep also confirmed the specificity of the primers

for rumen Treponema. No bacterial find more 16S rRNA gene sequences other than Treponema were detected in the libraries. Although primer sets that yield short amplicons are ideal for real-time PCR amplification, it was difficult to design primers that are specific for Treponema and yield a smaller PCR product. The g-TrepoF and the BAC926R primer set yield a relatively large (575 bp) PCR product. However, the standard curve for the assay was comparable to those of the total bacterial and T. bryantii species-specific primers producing PCR efficiencies >1.9 (Table 1). The dissociation curve obtained for the samples had a similar Farnesyltransferase melting point with the standard plasmid DNA, indicating that there were no nonspecific amplifications. The g-TrepoF and BAC926 primers produced a single dissociation curve peak at 90 °C when tested against DNA from T. bryantii and when using total rumen microbial DNA. The relative proportions of the 16S rRNA gene copies for the Treponema group and T. bryantii are shown in Table 2. The mean relative population size of the Treponema group in the total rumen bacteria of sheep fed alfalfa diet was as high as 1.05%, while that of T. bryantii was only 0.02%. Although the highest population size of Treponema was found

in the alfalfa-fed sheep, diet did not significantly affect the Treponema group (P=0.648) or the T. bryantii (P=0.977) population. The DNA fingerprints of T. bryantii showed a single band, while a number of bands were observed for the other Treponema in the rumen content DNA samples from sheep fed different diets. The DGGE profiles of the Treponema community associated with the hay (alfalfa and orchardgrass) and concentrate diets showed different banding patterns. The DGGE profiles across diet showed consistently fewer bands (except animal 3) in samples from concentrate-fed animals (Fig. 1). The PCA of the binary data of DGGE profiles distinguished Treponema population that associated with either the hay or the concentrate diets resulting in two clusters (Fig. 2), although one exception was observed.

Many organisms presenting OlsB homologs belong to the orders Acidithiobacillales, Chromatiales, Pseudomonadales, Methylococcales, and Thiotrichales. In this context, it has to be mentioned that OLs have been described in Serratia marcescens, which belongs to the Enterobacteriaceae (Miyazaki et al., 1993). Unfortunately, no complete genome sequence of S. marcescens has been published so far. Seliciclib manufacturer Within the Deltaproteobacteria, OlsB homologs are encoded in the genomes of Stigmatella aurantiaca, Bacteriovorax marinus, and Bdellovibrio bacteriovorus. Interestingly, OLs have been

detected in the Deltaproteobacterium Sorangium cellulosum So ce56 (Keck et al., 2011), but no gene encoding an OlsB homolog is present in the genome. The best hit when searching the S. cellulosum genome with OlsB from B. cenocepacia is the gene rimI1, which is predicted to encode a ribosomal protein alanine acetyltransferase (sce1382). This suggests that a second unrelated family of N-acyl transferases might be responsible for LOL formation in S. cellulosum and possibly in other bacteria. Among the actinomycetes are several species encoding OlsB homologs. Most of them can be classified into the families Gordoniaceae,

Micromonosporaceae, Mycobacteriaceae, Nocardiaceae, Pseudonocardiaceae, and Streptomyceteae. Among the spirochetes, several Dabrafenib species from the genus Leptospira present a gene encoding an OlsB homolog. Only very few species belonging to other taxonomical groups present a gene encoding an OlsB homolog in their genomes. Compared to the large number

of bacterial species that have been shown to form OL or that are predicted to be able to form OL, only few bacterial species have the now known OL-modifying enzymes. The identified OL hydroxylases belong either to the Fe2+/O2/α-ketoglutarate-dependent superfamily of hydroxylases (OlsC and OlsD) or to the di-iron fatty acid hydroxylase superfamily (OlsE) (Table S1). The phylogenetic distribution of these OL hydroxylases is described in the sections The OL hydroxylase OlsC’The OL hydroxylase OlsC ‘, The OL hydroxylase OlsD’The OL hydroxylase OlsD ‘ and below The OL hydroxylase OlsE’The OL hydroxylase OlsE ‘ and in Table S1. The 2-hydroxylase from Burkholderia species has not been isolated yet, so it is not known whether it belongs to the already mentioned superfamilies or to yet another superfamily such as the cytochrome P450-dependent enzymes (Matsunaga et al., 2000; Lee et al., 2003; Girhard et al., 2007; Fujishiro et al., 2011). As possible OL modifications might occur only under specific stress conditions, it is possible that additional modifications with their respective responsible enzymatic activities and genes will be found in the future in other organisms. It has been observed that the biosynthesis of OLs is regulated by the presence of certain nutrients in the growth medium. Some organisms such as S.

Note that a possible role of the pulvinar in the processing of pitch over time has also been reported in other studies investigating music, namely during melody

generation (Brown et al., 2006), and scale playing during piano performance (Parsons et al., 2005). Notably the pulvinar is probably most known for its implication in visual attention (Petersen et al., 1987; Posner & Petersen, 1990), and contains neurons that generate signals related to the salience of visual objects (Robinson & Petersen, 1992). The current observation of the pulvinar thus suggests that it may either play a more general cross-modal role in attention, e.g. in emotional attention (Vuilleumier, 2005), or

it may be recruited by auditory processes, although it is part of the visual system. Such a recruitment of well-known ‘visual OSI-744 ic50 system areas’ by music processing is not uncommon. For example, musical mental transformation of scales and melodies draws on brain regions known to be involved in mental rotation in the visual domain (Foster & Zatorre, 2010; Zatorre et al., 2010). Furthermore, listening Selleck ATM/ATR inhibitor to music can evoke visual imagery (Juslin & Västfjäll, 2008), and visual imagery may facilitate multiple aspects of music performance (Keller, 2012). Such a correspondence between visual and musical processing is further substantiated by the finding that musicians trained in an early life-time window performed better on visual–motor synchronisation tasks than late-trained musicians (Bailey & Penhune,

2012). Note that, because the acquired anatomical values are a quite rough measure to determine inter-subject differences in brain organisation, it is to be expected that an investigation of individual differences in a functional magnetic resonance imaging experiment with the same stimulus material would probably allow for a more detailed view of how the observed behavioral effects mafosfamide may correspond to functional networks. We complemented the main research goal above with calculations directly correlating valence for each condition with GMD. Of particular interest is the correlation of valence ratings of O with GMD, which showed higher GMD in parietal regions and temporal areas (Fig. 4A). Higher GMD in these regions is thus associated with higher valence ratings for the O. The observed inferior parietal lobe has previously been implicated in auditory spatial working memory (Alain et al., 2008), and musical pitch (Zatorre et al., 1994), and the adjacent intra-parietal sulcus has been shown to be involved in the mental transformation of scales and melodies (Foster & Zatorre, 2010; Zatorre et al., 2010).

, 1990). The atzDEF operon is transcribed divergently from a

single σ70-dependent promoter, PatzDEF, showing poor conservation at the −35 motif, a feature shared by other positively regulated promoters. The interaction of AtzR with the divergent atzR-atzDEF promoter region has been characterized in detail. AtzR binds to five consecutive major grooves overlapping the −24 motif of the PatzR promoter and the −35 motif of the PatzDEF promoter (Porrúa et al., 2010). This five-subsite structure fits well the general binding pattern described for several tetrameric LTTRs (Toledano et al., 1994; Hryniewicz & Kredich, Apoptosis inhibitor 1995; Wang & Winans, 1995). Accordingly, the two PatzDEF-distal subsites are enclosed within a G-C-rich 7-bp heptameric palindrome centered at position −65 from the atzDEF transcriptional start, bearing the conserved T-N11-A motif, conforming http://www.selleckchem.com/products/gsk-j4-hcl.html to a strong recognition element designated the repressor-binding site (RBS) (Porrúa et al., 2007). The additional three subsites conform to a weaker binding

element, designated the activator-binding site (ABS). While keeping two subunits tightly bound to the RBS, the two additional subunits can switch between two conformations: an extended conformation that interacts with the central and PatzDEF-proximal subsites and a compact conformation that interacts with the PatzDEF-distal and central subsites (Porrúa et al., 2010). This conformational change is of paramount importance to the activation mechanism and is discussed below. Two additional features

of the divergent PatzR-atzDEF promoter region are worth mentioning. First, there is a conspicuous absence of a binding site for NtrC, the activator of the PatzR promoter. Second, there is the presence of an as yet uncharacterized cis-acting element that influences atzDEF expression: serial Oxalosuccinic acid deletion analysis revealed that the removal of sequences between the atzR transcriptional start and the AtzR-binding site resulted in an ∼10-fold decrease in atzDEF expression under all conditions, whereas the general regulatory pattern is largely unaffected (Fig. 3). The nature and function of this overimposed regulation and the trans-acting factors that may be involved are currently unknown (Porrúa et al., 2007; O. Porrúa & F. Govantes, unpublished data). The regulatory gene atzR is transcribed from the single σ54-dependent PatzR promoter, which is activated by the enhancer-binding protein (EBP) NtrC in response to nitrogen limitation. However, the atzR-atzDEF promoter region does not contain an upstream activation sequence (UAS) for NtrC binding, and a sequence-specific interaction with the promoter region is not required for PatzR activation (Porrúa et al., 2009).