Both Polymyxa graminis and Polymyxa betae were identified This i

Both Polymyxa graminis and Polymyxa betae were identified. This is the first report of infection of Arabidopsis by Polymyxa spp. and shows the possibility selleck inhibitor of using this system for studies of infection biology and host–parasite interactions. Polymyxa spp. are a group of obligate root-infecting organisms belonging to the plasmodiophorid group that are important plant–virus vectors (Kanyuka et al., 2003). Polymyxa graminis transmits viruses such as soil-borne cereal mosaic virus (SBCMV), soil-borne wheat mosaic virus and wheat spindle streak mosaic virus to cereals. Polymyxa

betae transmits beet necrotic yellow vein virus, the cause of rhizomania, to sugar beet. Polymyxa graminis has a wide host range including wheat, barley, rye, rice, sorghum, groundnut and various grasses, whereas P. betae is mostly restricted to beet and other plants in the family Chenopodiaceae. A number of subgroups (ribotypes) of Polymyxa spp. have been identified according to rDNA sequence data (Ward et al., 1994, 2005; Ward & Adams, 1998; Legrève et al., 2002). Some of the P. graminis ribotypes appear to differ in host range and temperature requirements, leading to the suggestion that they should be classified as formae speciales (Legrève et al., 1998, 2002). Two groups of P. graminis isolates are found in temperate regions: ribotype I (f. sp. temperata) and ribotype II (f. sp. tepida). All SD-208 cost internal transcribed

spacer (ITS) rDNA sequences Morin Hydrate for P. betae reported to date fall

into two types that differ by only one base pair (Ward & Adams, 1998; Legrève et al., 2002). Because of their obligate nature and relatively long life cycle, Polymyxa spp. have been difficult to study. The development of a model system for studying Polymyxa–plant interactions would be extremely useful. Arabidopsis thaliana is an invaluable model system for several reasons: (1) short generation time, (2) the ability to grow large numbers in a relatively small space, (3) its ability to self-fertilize, (4) the large number of progeny that can be produced from a single plant, (5) its small haploid genome containing a relatively small number of repetitive genetic elements, (6) the availability of a fully sequenced genome, (7) the availability of mutagenized lines, (8) ease of transformation and (9) the large number of ecotypes exhibiting natural variation available (Meyerowitz, 1989). These features are in contrast to many crop species such as cereals, where genetic resources are less well advanced. Arabidopsis has already been used very successfully to study the interactions of another plasmodiophorid: Plasmodiophora brassicae (Koch et al., 1991). The ability to separate host sequences from those of Plasmodiophora by bioinformatics analysis has simplified the interpretation of data, for example from suppressive subtractive hybridization experiments to study gene structure and expression (Bulman et al., 2006, 2007).

After association, the mutants with different affinities for neut

After association, the mutants with different affinities for neutrophils, B- or T-lymphocytes, for example the rfa mutants, might be differently transported throughout the host’s body based on the B- or the T-lymphocyte tissue distribution. In addition,

because the rfa mutants have different affinities to neutrophils, B- and T-lymphocytes, they may also have different affinities to other cell types including the tumor cells expressing aberrantly glycosylated antigens (Hakomori, 1996; Newsom-Davis SB431542 purchase et al., 2009). Finally, after differential binding to target cells, S. enterica with a different lipopolysaccharide structure may also induce a different response in the target cells (Fig. 2, see also Matiasovic et al., 2011), which further extends the potential for this system to be subjected to more detailed testing. This work has been supported by the projects MZE0002716202 and QH81062 of the Czech Ministry of Agriculture, AdmireVet project CZ.1.05/2.1.00/01.0006 from the Czech Ministry of Education and 524/08/1606 project from the Czech Science Foundation. “
“Brucella abortus has been shown to produce two siderophores: 2,3-dihydroxybenzoic acid (2,3-DHBA) and brucebactin. Previous studies on Brucella have shown that 2,3-DHBA is associated with erythritol utilization and virulence in pregnant ruminants. The biosynthetic

pathway and role of brucebactin are not known and the only gene shown to be involved so far is entF. Using cre-lox methodology, selleck chemicals an entF mutant

was created in wild-type B. abortus 2308. Compared with the wild-type strain, the ΔentF strain showed significant growth inhibition in iron minimal media that became exacerbated in the presence of an iron chelator. For the first time, we have demonstrated the death of the ΔentF strain under iron-limiting conditions in the presence of erythritol. Addition oxyclozanide of FeCl3 restored the growth of the ΔentF strain, suggesting a significant role in iron acquisition. Further, complementation of the ΔentF strain using a plasmid containing an entF gene suggested the absence of any polar effects. In contrast, there was no significant difference in survival and growth between the ΔentF and wild-type strains grown in the murine macrophage cell line J774A.1, suggesting that an alternate iron acquisition pathway is present in Brucella when grown intracellulary. Iron is the second most abundant metal on earth (Clarke et al., 2001), and throughout evolution, most organisms have evolved or acquired iron-dependent enzymes that are involved in the essential life processes including electron transport and glycolysis (Wandersman & Delepelaire, 2004). Although iron is abundant in the environment, it is not readily available inside the host (Payne, 1993). The host limits the availability of free iron to prevent either oxidative damage to itself or replication of pathogens.

tuberculosis have been synthesized (Lilienkampf

et al, 2

tuberculosis have been synthesized (Lilienkampf

et al., 2009; Upadhayaya et al., 2009). Diarylquinolines were also shown to kill dormant M. tuberculosis as effectively as replicating bacilli and to inhibit ATP synthesis in dormant M. smegmatis (Koul et al., 2008). This unique dual bactericidal activity, with equal potency on replicating and dormant bacilli, distinguishes diarylquinolines from all the currently used antituberculosis drugs, such as isoniazid and rifampicin. UK-371804 These front-line drugs show significantly less activity on dormant mycobacteria as compared with replicating bacilli (Koul et al., 2008; Rao et al., 2008). Thus, although ATP synthase is significantly downregulated during dormancy, its residual activity MS-275 appears to be essential for mycobacteria irrespective of their

physiological state. This makes ATP synthase an efficient drug target to tackle both replicating as well as dormant bacilli. In vivo experiments using mouse models indicated that diarylquinolines have bactericidal activity exceeding the effect of current first-line antibiotics (Andries et al., 2005; Lounis et al., 2006). Diarylquinolines, in particular when applied in combination therapy with the first-line antibiotic pyrazinamide, have a strong potential for shortening the duration of tuberculosis treatment (Lounis et al., 2006; Ibrahim et al., 2007). The physiological basis for this observed synergy remains obscure. In phase IIb clinical tests, the addition of TMC207 to standard therapy strongly decreased the count of CFU in the sputum of patients with multi-drug-resistant tuberculosis as compared these with an active-placebo group (Diacon et al., 2009). TMC207 also accelerated conversion to a negative sputum culture, as compared with a placebo. These findings validate ATP synthase as a target for the treatment of tuberculosis. Respiratory ATP production is not only essential for growth, but also represents a critical weak point in dormant mycobacteria. Although most enzymes involved in respiratory

ATP synthesis are conserved between prokaryotes and eukaryotes, targeting ATP production may be a highly efficient approach for the development of antibacterial drugs. The strategy may be to target enzymes, which do not have homologs in human metabolism, as in the case of NDH-2. Alternatively, as applied for ATP synthase, small differences in the structure between a bacterial enzyme and a human homologue may be utilized for selective inhibition. Understanding respiratory ATP production in replicating and dormant mycobacteria will not only fuel development of novel drugs but also shed light on how these bacteria perform their intriguing task of extreme persistence without significant growth. The authors wish to thank Prof. Dr H. Lill (VU Amsterdam) and Prof. Dr K. Andries (Johnson and Johnson) for critically reading the manuscript, and Dr J. Guillemont, Dr E.

5) The results for the perceptual matching study (ie A-A; see

5). The results for the perceptual matching study (i.e. A-A; see Fig. 5A) support the neural compensation hypothesis of cognitive reserve, as the activated regions underlying task performance

differed in the younger and older groups. The older group recruited the bilateral frontal superior gyri more than the younger one, as in the PASA phenomenon, even at the lowest attentional load level (i.e. three letters). In addition, the elderly participants were found to use neural compensation and neural reserve concurrently to cope with increasing attentional load (i.e. five letters) for perceptual find more processing. These results support a previous study (Townsend et al., 2006) which investigated auditory and visual selective attention and cross-modal attention shifts using fMRI. They showed age-related differences in BOLD responses. The most striking of these differences were bilateral frontal and parietal regions of significantly increased activation in older adults during both focused and shifting attention. These data suggest that this increased activation reflected not new recruitment but reliance on brain regions typically used by younger adults when task demands are greater. These patterns may reflect compensatory neural recruitment. The results for the

naming matching study (i.e. a-A; see Fig. 5B) indicate a load-dependent Talazoparib datasheet PASA, supporting the hypothesis that an enhanced compensatory mechanism is required for the most demanding Mirabegron condition (i.e. five letters). Thus, cerebral

reorganization of visual selective attention implies an intrahemispheric PASA phenomenon suggesting neural compensation. To cope with increased cognitive demand, neural reserve can also be recruited in basic perceptual processing (i.e. A-A; five letters), while the recruitment of compensation mechanisms increases in more complex processing (i.e. a-A; five letters). Taken together, these results suggest that the two neural mechanisms, compensation and reserve, are engaged in a flexible and adaptive manner, and are deployed depending on cognitive demand and on the nature of the required processing. Some of the evidence discussed here suggests that the functional reorganization of the brain that allows for the preservation of cognitive abilities takes many different forms, which cannot be universally predicted. Successful cognitive aging relies on neurofunctional flexibility, which enables the aging brain to cope with the challenges posed by declining neural structures. This flexibility is provided by dynamic neurofunctional adaptive mechanisms (a form of cerebral plasticity) that allow for the optimal engagement of the age-affected resources and recourse to the most advantageous distribution of cognitive processing and resources within the aging brain. This evidence suggests that neurofunctional reorganization in aging is based on a more flexible and adaptive neurofunctional process than had previously been proposed.

Two plasmids

Two plasmids GSK1120212 molecular weight were constructed to complement this mutant. Because promoters of B. burgdorferi often overlap the preceding ORF (Cabello et al., 2006), one of these, pAB63 (Fig. 1b), contained both the

uvrABbu ORF and the 504 bp upstream of the translational start of uvrA. The other, pMS9 (Fig. 1b), contained the uvrABbu ORF under the control of the borrelial flaB promoter. Electroporation of these plasmids and the pKFSS1 vector control into B. burgdorferiΔuvrABbu, followed by selection and passaging yielded clones containing both full-length and disrupted uvrABbu (Fig. S1a) that expressed uvrA mRNA transcripts (Fig. S1a). Reactions performed without reverse transcriptase showed no amplicons and confirmed the lack of DNA contamination in total RNA samples (data not shown). UV irradiation damages

DNA by generating intrachain thymine dimers (Black et al., 1998; Aertsen et al., 2004; Fry et al., 2005; Maul & Sutton, 2005). Exposure of the parental strain to 800 and 1000 μJ cm−2 of UV radiation had little effect on its survival, while exposure of ΔuvrABbu or its derivative containing only the pKFSS1 cloning vector to these doses resulted in complete loss of viability (Fig. 2a and b). Significant complementation of the phenotypic defect of the inactivation mutant was obtained with both pAB63 and pMS9 (P<0.001). The inability of the inactivation mutant to survive UV radiation was partially corrected by pAB63 (uvrABbu and 504 bp 5′ up to the uvrABbu start codon, Fig. 2a) and fully corrected by pMS9 (Fig. 2b). This indicates that the uvrABbu gene product is involved in the ability of B. burgdorferi find more to repair Baricitinib intrachain DNA damage. MMC, a nucleotide-akylating agent, cross-links DNA (Iyer & Szybalski, 1963). Bacterial mutants with various defects in DNA repair have been found to be more susceptible to growth inhibition by this agent than are wild type (Bijlsma et al., 2000; Liveris et al., 2004). In the absence of MMC, wild type, the ΔuvrABbu inactivation mutant and its pAB63 (not shown), pMS9 or pKFSS1 derivatives (Fig. 3a) grew equally well in complete BSK-H. All strains reached log-phase

density (about 108 cells mL−1) by day 4 of culture. In the presence of MMC, the growth of ΔuvrABbu was significantly (P<0.001) inhibited [concentrations examined: 0.1 μg mL−1 (data not shown), 1 μg mL−1 (data not shown), 5 μg mL−1 (Fig. 3b), 10 μg mL−1 (Fig. 3c)]. This growth inhibition was reversed by extrachromosomal complementation of ΔuvrABbu with pMS9 (uvrABbu under the control of flaBp) but not with the cloning vector pKFSS1 (Fig. 3b and c). Similar results were obtained using pAB63 (uvrABbu under the control of 504 upstream nucleotides) to complement ΔuvrABbu (data not shown). This indicates that the uvrABbu gene product is involved in repair of interchain repair of DNA damage in B. burgdorferi, in striking difference to the situation in E.

Percentage of patients who confirm they have been given the oppor

Percentage of patients who confirm they have been given the opportunity to be involved in making decisions about their treatment. Patients should be given the opportunity to be involved in making decisions about their treatment [1]. Studies show that trust, a good-quality relationship and good communication skills between doctor and patient are associated with better adherence and treatment outcomes in HIV and in other disease areas [2-6]. Studies have shown that patient beliefs about

the necessity, efficacy and side effects of ART, the practicability of taking it, and beliefs about their ability to adhere to therapy, all affect adherence [7-9]. Before prescribing ART (treatment initiation or switching), clinicians should assess: Patients’ readiness to take therapy. Their knowledge of its GSI-IX mode selleck products of action and efficacy, and perceptions of their personal need for ART. Concerns about taking ART or specific ARV drugs, including potential adverse effects. Concerns with possible adverse social consequences, such as disclosure or interference with lifestyle. Their confidence that they will be able to adhere to the medication (self-efficacy); Psychological or NC issues that could impact on adherence; Socio-economic factors that could impact

on adherence, including, but not limited to, poverty, housing, immigration status or domestic violence. Community advocacy and peer support are helpful in supporting a patient’s understanding and confidence around treatments and help the patient’s readiness and decision to start therapy. Community organizations in the UK have been instrumental in providing a range of patient-information resources and peer-support services, including published and web-based information materials, telephone advice lines, treatment advocates and peer-support groups, working in collaboration with healthcare professionals. They are an important and essential adjunct to clinic-based

services and are helpful in addressing the issues discussed below. A number of patient factors may affect adherence, adverse effects and treatment outcomes. Depression is significantly associated with low adherence [10, 11] and some studies report an independent association between depression and mortality in people with HIV [12]. Glycogen branching enzyme Adherence can be improved by treating depression [13], so all patients should be screened for depression before starting therapy, using simple screening tools such as the Arroll two-question quick screen [14]. Patients should also be screened for anxiety and for cognitive impairment. Current problematic alcohol and recreational drug use are also associated with low adherence [15-17], although a history of injecting drug use, or even active use, is not necessarily so [18]. Patients should be asked about alcohol and recreational drug use and offered support to moderate or manage it if desired.

The parental strains PG31 and S6 were included in each MIC test a

The parental strains PG31 and S6 were included in each MIC test as a control. A portion of the gene encoding domain V of 23S rRNA gene and the entire gene encoding ribosome protein L3 were amplified by PCR with specific primers. The primers were designed from the complete genome sequence of M. gallisepticum strain A5969 (GenBank accession no. AE015450). Because M. gallisepticum possesses two copies of the 23S rRNA gene (Chen & Finch, 1989), two pairs of primers (primer

pair MG23A-F and MG23A-R and primer pair MG23B-F and MG23B-R) were designed to amplify each 23S rRNA gene independently. Two internal primers, MGF-1879 and MGR-2763, were used to amplify domain V of 23S rRNA gene. Amplification of the entire gene of ribosomal protein L3 was performed with the primer pair L3-F and L3-R. The primers and reaction conditions are shown in Table 1. PCR products were purified using the this website QIAquick Gel Extraction Kit (Qiagen) and sequenced using the same primers as those used for PCR. Random amplified polymorphic DNA (RAPD) analysis was performed, as described previously (Pakpinyo & Sasipreeyajan, 2007), to confirm that the mutants were derived from the corresponding parental strain. Mycoplasma gallisepticum mutants

with decreased susceptibility to pleuromutilins could be selected by serial passages of the parental strains M. gallisepticum S6 and PG31 in subinhibitory concentrations of tiamulin or valnemulin. Ibrutinib concentration For the purposes of this study, we defined that the mutant exhibits resistance when the MIC increased ≥8-fold in comparison with the MIC obtained for the corresponding parental strain. Three subcultured clones from the passage with significantly increased MIC were studied. MICs of only one clone are shown in Table 2 because no significant difference was observed between the three clones. The resistance phenotype of all mutants was stable after five consecutive subcultures in an antibiotic-free

medium. Moreover, the RAPD experiments showed that the profiles of the mutants were identical to the profile of the corresponding parental strain (data not shown). For the mutants, the MICs of tiamulin ranged from 0.5 to 64 μg mL−1, and the MICs of valnemulin ranged from 0.032 to 32 μg mL−1. The concentrations of valnemulin required to inhibit each acquired mutant were significantly lower than those for tiamulin (Table 2). Two susceptible strains PG31 and S6 were used for the selection. Although 10 passages were performed for both parental strains, the results of selection showed marked differences between the strains PG31 and S6. The highest tiamulin MIC for the mutants derived from PG31 was 16 μg mL−1, compared with 64 μg mL−1 for the mutants derived from S6, and the highest valnemulin MIC for the mutants derived from PG31 was 0.25 μg mL−1, compared with 32 μg mL−1 for the mutants derived from S6.

We have also observed that MIFs are significantly

more in

We have also observed that MIFs are significantly

more infectious in human pneumocyte cells compared with SPFs. These results strongly suggest a potential role of ciliates in increasing the risk of legionellosis. Legionella pneumophila, a ubiquitous gram-negative freshwater bacteria, is an intracellular pathogen of freshwater amoeba that, when aerosolized, can cause progestogen antagonist a severe pneumonia known as legionellosis or Legionnaires’ disease in susceptible individuals (Fields et al., 2002). Legionellosis is considered an environmental disease because person-to-person transmission does not occur. Therefore, transmission of legionellosis is primarily linked to man-made devices (e.g. cooling towers, whirlpool

spas) that produce aerosols from warm water contaminated with Legionella. The relationship between L. pneumophila and protozoa has been described as very important check details for two main reasons: (i) protozoa provide protection against environmental stresses (Barbaree et al., 1986) and (ii) protozoa, particularly amoeba, provide the principal natural haven for Legionella replication (Rowbotham, 1980; Borella et al., 2005). In this respect, it is known that L. pneumophila multiplies inside free-living amoebae and could be released as free bacterial cells or as groups of cells enclosed in vesicles (for recent reviews see Borella et al., 2005; Bichai et al., 2008). The role of vesicles as complex infectious particles has been hypothesized to be important in the transmission of L. pneumophila and legionellosis (Rowbotham, 1983). Tetrahymena spp. are ciliated protozoa that, depending on the incubation temperature, can support the growth of Legionella (Fields et al., 1984; Barbaree et al., 1986; Berk et al., 2008). In the species Tetrahymena tropicalis, L. pneumophila is efficiently ingested but does not replicate inside food vacuoles, in spite of resisting Amobarbital digestion.

Consequently, live L. pneumophila resides transiently (1–2 h) in the food vacuoles before being expelled in the form of pellets. Legionella pellets are clusters of up to 100–200 L. pneumophila cells kept together by outer membrane fragments derived from a few digested legionellae reflecting massive ingestion by Tetrahymena, and perhaps a ciliate-derived material from the lumen of food vacuoles (Berk et al., 2008). In addition, the surviving L. pneumophila cells present in the pellets expelled by T. tropicalis have all the morphological characteristics of mature intracellular forms (MIFs) (Faulkner et al., 2008), initially described in HeLa cells (Garduno et al., 2002). In a previous study, we observed that passage of L. pneumophila in free-living amoebae produces legionellae able to survive numerous adverse conditions such as starvation and antibiotic presence (Bouyer et al., 2007). The aim of this study was to determine whether passage of L.

coli lacZ gene The resulting reporter plasmids

(listed i

coli lacZ gene. The resulting reporter plasmids

(listed in Table 1) were conjugationally transferred to R. capsulatus wild-type and mutant strains defective for mopA, mopB, or both. Rhodobacter capsulatus reporter strains were grown in a molybdenum-free AK-NL minimal medium containing 9.5 mM serine as the sole source of nitrogen. When required, Na2MoO4 was added to a ZD1839 ic50 final concentration of 10 μM. Following growth to the late exponential phase, β-galactosidase activities were determined as described previously (Miller, 1972; Sicking et al., 2005). Purification of His-tagged MopA and MopB proteins from E. coli, and gel-shift assays were carried out as described previously (Wiethaus et al., 2006). Escherichia coli BL21(DE3) strains carrying either plasmid

pJW32 (mopAhis) or pJW33 (mopBhis) were used to overexpress recombinant regulator proteins. Primer pairs 5′-ACGGGCAGGCGCGGGGTTCT-3′/5′-CCGGCATTCGCCGGTGAAGCACTG-3′ and 5′-GGCACTGACCGACCTTTTGACC-3′/5′-CCAGTGTTAACCTTTGCTACCCCTTTG-3′ were used to PCR amplify 209-bp anfA (Fig. 1b) and 138-bp mop promoter fragments (Fig. 1c), respectively, with the pBluescript derivatives carrying the respective anfA and mop promoter variants (Table 1) as templates. The 5′ ends of PCR products were 32P-labeled with T4 polynucleotide kinase (Fermentas, St. Leon-Rot, Germany). Up to 150 pmol of regulator proteins were preincubated in buffer B [40 mM NaH2PO4 (pH 8.0), 500 mM NaCl] at room temperature in a total volume of 16 μL. After 10 min, a mixture of 1 μL 32P-labeled DNA (5 fmol μL−1), 1 μL poly(dI-dC) (1 μg μL−1), and 2 μL binding buffer [25 mM HEPES (pH 8.0), 50 mM K-glutamate, 50 mM MgSO4, 1 mM DTT, 0.1 mM EDTA, 0.05% Igepal CA-630] was added. Samples were incubated at 30 °C for 20 min, before free and bound DNAs were separated on 6% polyacrylamide gels. 32P-labeled bands were documented using an Amersham Hyperfilm™ MP (GE Healthcare, Freiburg, Germany). To date, five molybdate (Mo)-regulated promoters have been described Ribonucleotide reductase for R. capsulatus (Wiethaus et al., 2006) (Fig. 1a). In the presence of Mo, the transcription of morC, morAB, mopA-modABCD, and anfA is repressed by either MopA or MopB, while mop is exclusively activated by MopA. In line with reporter gene studies, both regulators bind all Mo-repressed promoters in vitro, while only MopA (but not MopB) binds the Mo-activated mop promoter. All five promoters contain conserved sequences of dyad symmetry called Mo-boxes (Fig. 1a). Deletion of one or five nucleotides from the anfA-Mo-box completely abolished Mo repression of anfA (Kutsche et al., 1996), strongly suggesting that the anfA-Mo-box is essential for binding of MopA and MopB. A core consensus sequence (CG-N-TAT-N13-ATA-N2-G) is strictly conserved in all Mo-repressed and Mo-activated Mo-boxes (Fig. 1a; Consensus C). In addition to these key nucleotides, further bases are conserved between strongly repressed Mo-boxes.

aeruginosa PAO1 mutant strain unable to produce the type III secr

aeruginosa PAO1 mutant strain unable to produce the type III secretion system effector gene pcrV BMS-354825 purchase (strain PW4017). Our results suggest that AZM-pretreated P. aeruginosa could indirectly exacerbate pro-inflammation by inducing IL-8 production in HBEs. “
“PyrH is a member of the UMP kinase family that catalyses the conversion of UMP to UDP, an essential step in the pyrimidine metabolic pathway in a variety of bacteria including those causing community-acquired respiratory tract

infections (RTIs). In this study, we have developed a luminescence-based kinase assay of PyrH and evaluated the inhibitory activity of PYRH-1 (sodium 3-[4-tert-butyl-3-(9H-xanthen-9-ylacetylamino)phenyl]-1-cyclohexylmethylpropoxycarbonyloxyacetate).

PYRH-1 inhibits PyrH derived from both Streptococcus pneumoniae and Haemophilus influenzae with IC50 (concentration of inhibitor giving a 50% decrease in enzyme activity) values of 48 and 75 μM, respectively, whose inhibitory activity against S. pneumoniae PyrH was far higher compared with that of UTP (IC50 = 710 μM), an allosteric PyrH inhibitor. The molecular interaction learn more analysis by surface plasmon resonance suggested that PYRH-1 directly interacts with S. pneumoniae PyrH at one-to-one molar ratio. Finally, PYRH-1 was shown to have antimicrobial activity against several different bacteria causing RTIs, such as S. pneumoniae,Staphylococcus aureus,H. influenzae (acrA knockout strain), suggesting that PYRH-1 is a prototype chemical compound that can be harnessed as an antimicrobial drug with a novel mode of action by targeting bacterial PyrH. Although numerous antibiotics for community-acquired bacterial respiratory tract infection (RTIs) have been

discovered, thus far, most of them target the same or functionally similar molecules that are essential for bacterial growth. Because emerging antibiotic-resistant bacteria, such as multidrug-resistant Streptococcus pneumoniae and β-lactamase-negative and ampicillin-resistant Haemophilus influenzae (BLNAR), are posing threats, especially to immunocompromised patients, there is an unmet medical need to provide antibiotics with Glutamate dehydrogenase novel modes of action for reducing infections associated with such bacteria. Recent progress in the genome projects (Fleischmann et al., 1995; Hoskins et al., 2001; Kuroda et al., 2001) has decoded the genome structure of a variety of organisms such as S. pneumoniae, Staphylococcus aureus and H. influenzae, thereby creating opportunities to design molecular targeting strategies for discovering agents that specifically attack pathogens. In fact, a number of studies in pharmaceutical companies and academia have developed screening platforms based on enzymatic assay and structure-based drug design.