(a) 10, (b) 60 and (c) 144 min. The scale bar is 500 nm. Figure 3 Measured NWs diameter Repotrectinib datasheet and length (a) and axial growth rate (b) as function of growth time. Inset shows the dependence of the ratio of deposited volume between radial and axial growth on growth time. The major contributions to the axial growth of NWs include the following : (i) impingement of adatoms on the top of NWs directly, (ii) impingement on the substrate surface and diffusion up the sidewalls, and (iii) impingement on sidewall and diffusion up
to the top of NWs. Although this is for VLS growth mechanism, we believe that the principle is applicable to VS growth mode. The major contributors for axial and lateral growths are the adatoms impinging on the surface around NW and on the sidewall of NW. All the adatoms collected from these two sources are finally incorporated into NW growth either through liquid droplet or nucleate directly onto the top of NW, so there is no significant difference between VLS and VS in terms of growth contribution from impinging adatoms. It is well accepted that the contribution from direct impingement on the top of NWs is negligible. The fast increasing growth rate in the beginning is due to the
significant contribution from adatoms collected by the surface. With the growth of NWs, more and larger parasitic islands grow on the surface so that the surface area around the NWs collecting incoming adatoms decreases, leading tuclazepam to SIS3 in vivo a reduced contribution from surface collection, and consequently the contribution from sidewall impingement becomes dominant. The axial growth rate, GR, due to the sidewall impingement can be expressed as . where R is the NW radius, L diff is diffusion length along the sidewall, θ is the in-plane angle of the normal sidewall with respect
to the beam direction, φ is the angle of incident beam to the substrate, and F in is the nominal growth rate. The value of θ varies from 0° to 30° due to hexagonal find more symmetry of the NWs, φ is 30° as defined by our system. Since no tapered NW was observed in our growths, it is obvious that all of the impinging adatoms diffuse along the entire NW length, i.e. the diffusion length is much longer than the length of NWs in our growth. Taking into account the nominal growth rate of 0.1 μm h−1, NWs radius of 0.041 μm, and assuming L diff > length of NWs L, we can estimate the growth rate dependence on L as shown in Figure 3b. The radial growth was accounted in the calculation. It can be seen that the experimental growth rate does not follow the calculated dependence. The slower increase of growth rate with growth time can be due to the limitation of the adatoms’ diffusion along the sidewall. However, this is not the case in our growths since no tapering is visible. This assumption is consistent to the demonstrations in InAs NWs on Si .
hDM-C6 MH3B1 is see more relatively stable in the presence of serum at 37°C. Comparison of the structures of hDM and the wild type enzyme as well as analysis of potential MHCII binding peptides generated as a result of fusion of two proteins and the
Glu201Gln:Asn243Asp mutations suggest that hDM-αH-C6.5 MH3B1 should have minimal immunogenicity in humans. Therefore, the hDM-C6 MH3B1-F-dAdo combination addresses many of the current limitations of ADEPT and provides an excellent candidate for treatment of HER2/neu expressing tumors with minimum systemic toxicity or immunogenicity. Methods Materials Guanosine and F-Ade were purchased from Sigma-Aldrich (St. Louis, MO), and F-dAdo was purchased from Berry & Associates (Dexter, MI). CT26 was purchased from ATCC ( Manassas, VA). Construction and characterization of CT26HER2/neu is described previously . MCF7-HER2  was a gift from Dr. Dennis Slamon (University of this website California, Los-Angeles). Cells were cultured in Iscove’s Modified Dulbecco’s Medium (IMDM; GIBCO, Carlsbad, CA) containing 5% calf-serum (GIBCO) for CT26 and CT26HER2/neu and IMDM containing 10% fetal bovine serum (GIBCO), 1% non-essential amino acids (GIBCO) and 1% sodium pyruvate https://www.selleckchem.com/products/CP-673451.html (GIBCO) for MCF-7HER2 cells. The expression vector for production of ECDHER2 was a gift from Dr. James Marks (University of California, San-Francisco). Plasmid construction and protein purification
Cloning of hPNP and hDM with αH linker at its C-terminus was Ketotifen described previously . To construct hPNP-αH-C6.5 MH3B1 or hDM-αH-C6.5 MH3B1 genes,
first PNP-αH was amplified using 5′ gcggccgc gataccaccgatatccaccatggagacagacacactcctgctatgggtactgctgctctgggttccaggttccactggagacgagaatggatac acctatgaagattataagaac3′ and 5′taaagaggccgcagccaaagcgcaggtgcagctggtgcagtctgg3′ as forward and reverse primers respectively. The forward primer contains a NotI site, Kozak sequence and signal peptide, and the beginning of the PNP gene. The reverse primer encodes the αH linker and the beginning of C6.5 MH3B1. The sequence for the signal peptide is gatatccaccatggagacagacacactcctgctatgggtactgctgctctgggttccaggttccactggagac. The amino acid sequence for the αH linker is AEAAAKEAAAKA. The C6 MH3-B1 gene was PCR amplified with the forward primer complementary to the reverse primer used for PNP amplification encoding for αH linker, and the beginning of the C6.5 MH3B1 sequence. 5′ggagggaccaaggtcaccgtcctaggtcgttaataa tctaga 3′, which encodes the C-terminus of scFv and an XbaI site, was used for the reverse primer. The PCR product of each gene was purified, annealed and used as template for the final PCR amplification using PNP forward primer containing a NotI site and C6.5 MH3B1 reverse primer containing a XbaI site. The PCR product was cloned into the TOPO-Blunt vector (Invitrogen, Carlsbad, CA) and the sequence confirmed.
The changes in fracture risk, back pain and HRQoL during 18 months of teriparatide treatment in EFOS have been previously https://www.selleckchem.com/products/ly3039478.html reported . Methods Study design and patients The study design and characteristics of the EFOS patient population have been described previously . this website Briefly, 1,649 postmenopausal women with a diagnosis of osteoporosis who were about to initiate teriparatide treatment were enrolled in eight European countries (Austria, Denmark, France, Germany, Greece, Ireland, the Netherlands, and Sweden). Patients were followed for the duration of their teriparatide treatment, which they could discontinue at any time, and were asked to return
for two additional visits after they discontinued teriparatide. Patients were not included if they were currently being treated with an investigational drug or procedure, or had any contraindications Duvelisib chemical structure as described in the
teriparatide label. Because this was an observational study, there were no further restrictions for the selection of patients. Patients gave written informed consent prior to enrolment and were able to withdraw without consequence at any time. The study was approved by local ethics committees or review boards, depending on local requirements. Data collection At the baseline visit, patient demographic characteristics, risk factors for osteoporosis and falls, osteoporosis therapies and disease status were recorded . The women attended visits at baseline and at approximately 3, 6, 12 and 18 months after teriparatide initiation, and at 6 and 18 months after discontinuing teriparatide treatment. Incident OSBPL9 clinical vertebral and non-vertebral fractures, the primary study endpoint, were diagnosed and confirmed by review of the original X-rays and/or the radiology or surgical reports at the investigational site. A new or worsened vertebral fracture was defined from the presence of a confirmed radiographic vertebral fracture associated with signs and/or symptoms, such as acute or severe back pain, suggestive of a vertebral fracture . Back pain was self-assessed by patients at each visit using a back pain questionnaire
detailing frequency and severity in the past month, limitations of activities and days in bed due to back pain . Patients also rated their back pain severity using a horizontal 100 mm visual analogue scale (VAS), ranging from 0 mm (no back pain) to 100 mm (worst possible back pain). This type of VAS is reliable and reproducible for the measurement of pain . Spontaneously reported adverse events were collected throughout the study. Statistical analysis Data were analysed for the total study cohort, which included all patients with a baseline visit and at least one follow-up visit. In addition, the post-teriparatide cohort included those patients who discontinued teriparatide and had at least one post-teriparatide follow-up visit. Results for the active treatment period have already been published .
An inhibitory activity on ribonucleotide reductase could also be demonstrated for FWGE, allowing FWGE to interfere with nucleic acid-synthesis by several pathways [1, 8, 11]. Beside the single agent cytotoxic activity of FWGE against human tumor cell lines and human tumor xenografts some data suggest synergistic drug interaction between 5-FU or DTIC in a limited number of cell lines [2, 6]. In addition to the preclinical data there https://www.selleckchem.com/products/smoothened-agonist-sag-hcl.html are already a few clinical studies published which suggest some beneficial effect of FWGE in
human cancer therapy. The most impressive data were RAD001 cost generated in a randomized Phase II trial by Demidov et al. who observed a significant gain in progression free survival and overall survival for the combination of DTIC and FWGE as compared to DTIC alone in melanoma patients . A study conducted by Jakab et al. in patients with colorectal cancer found an enhanced survival and reduced metastasis formation for the combination of chemotherapy and FWGE as compared to chemotherapy alone group. In a multivariate analysis of this study only tumor stage and FWGE treatment were the only significant predictors of survival . However, this data have to be interpreted with caution since the study had a non randomized design and the patient groups were not balanced [1, 13]. Of similar importance, several studies including the ones cited
above suggested an improvement of quality of life due to co treatment 7-Cl-O-Nec1 with FWGE . Overall, the limited preclinical and clinical data available suggest some
promising activity profile of FWGE as a nutriment for cancer patients but also a potential anticancer agent. In this broad in vitro study we aimed to analyze the single agent activity of FWGE as well as its interaction with the commonly used drugs 5-FU, oxaliplatin and irinotecan in a large panel of human cancer cell lines Unoprostone from different tumor entities. These data are of potential value to direct the further development FWGE in different cancer types and to help to select potential drug partners for the future development of combinations of chemotherapy regimens with FWGE. Materials and methods Drugs and chemicals FWGE was a generous gift from Biropharma Ltd, Kunfeherto, Hungary. FWGE was stored as dried powder at 4°C until use. For experimentation, FWGE was freshly prepared in sterile water to a final concentration of 100 mg/ml. After solution FWGE was centrifuged with 150 g to remove the insoluble material. 5-FU, Irinotecan, Oxaliplatin and Sulforhodamine B were purchased from Sigma Chemical Company, Germany. RPMI 1640 and Penicillin/Streptomycin were obtained from PAA, Pasching, Austria. FBS was purchased Biochrom AG, Berlin, Germany. Cell lines and culture The following human cancer cell lines were used for experimentation: testicular cancer (H12.
When patients with appendicitis were excluded, there was no difference in mortality or complications between patients with CIAIs and NIAIs. Source control represents a key component of success in therapy of sepsis. It includes LY2874455 molecular weight drainage of infected fluids, debridement of infected soft tissues, removal of infected devices or foreign bodies, and finally, definite measures
to correct anatomic derangement resulting in ongoing microbial YH25448 mouse contamination and to restore optimal function. Recommendations have low grade due to the difficulty to perform appropriate randomized clinical trials in this respect. Percutaneous abscess drainage should be the primary procedure to treat postoperative localized intra-abdominal abscess without signs of generalized peritonitis (Recommendation 2 C). Some retrospective studies in the surgery and radiology
literature have documented the effectiveness of percutaneous drainage to treat postoperative localized intra-abdominal abscess [257–259]. Source control should be obtained as early as possible after the diagnosis of postoperative intra-abdominal peritonitis has been confirmed. Inability to control the septic source is associated significantly with increase in mortality (Recommendation 1 C). Inability to control the septic source is associated significantly with increase in mortality. Delaying relaparotomy for more than 24 h or the presence of organ failure result in higher Non-specific serine/threonine protein kinase mortality in postoperative intra-abdominal infections. The value of physical tests and laboratory parameters in diagnosing
abdominal sepsis is limited. CT-scanning revealed the highest diagnostic accuracy. check details Early relaparotomy appears to be the most reasonable option to treat postoperative peritonitis . Re-laparotomy strategy Some patients are prone to persisting intra-abdominal infection regardless of eradication of the source of infection and timely relaparotomy provides the only surgical option that significantly improves outcome. In these cases single operation may not be sufficient to achieve source control, thus re-exploration is necessary [261–263]. The decision to and when to perform a relaparotomy in secondary peritonitis is largely subjective and based on professional experience. Factors indicative of progressive or persistent organ failure during early postoperative follow-up are the best indicators for ongoing infection and associated positive findings at relaparotomy [264–266]. Three methods of local mechanical management of abdominal sepsis following initial laparotomy for source control are currently debated: (1) Open-abdomen (2) planned relaparotomy (3) on-demand relaparotomy On demand relaparotomy may be considered the preferred surgical strategy in patients with severe peritonitis because it has a substantial reduction in relaparotomies, health care utilization, and medical costs. (Recommendation 1 A) In 2007 van Ruler and coll.
The visual results of the macrobroth dilution standard method is shown on the left (A and D), along with the time course results of the
ETGA (B and E) and gsPCR (C and F) AST analyses, plotting Ct versus time. Vertical, dashed lines indicate when aliquots were removed for analysis. Since Ct values are inversely related to signal selleckchem strength, the y-axes are inverted to visually demonstrate a rise in signal over time. Figure 4 E. coli selleck compound against ciprofloxacin and tetracycline AST results. The visual results of the macrobroth dilution standard method is shown on the left (A and D), along with the time course results of the ETGA (B and E) and gsPCR (C and F) AST analyses, plotting Ct versus time. Vertical, dashed lines indicate when aliquots were removed for analysis. Since Ct values are inversely related to signal strength, the y-axes are inverted to visually
demonstrate a rise in signal over time. Table 1 Comparison of minimum inhibitory concentration results for MSSA, MRSA and E. coli strains S. aureus ATCC 29213 Bacteria from purified cultures Belinostat supplier Bacteria harvested from a positive blood culture bottle Drug Phenotype CLSI MIC interpretation Macrobroth MIC and interpretation ETGA MIC and interpretation gsPCR MIC and interpretation ETGA MIC and interpretation gsPCR MIC and interpretation 4 hr 6 hr 22 hr 4 hr 6 hr 22 hr 4 hr 6 hr 4 hr 6 hr Oxacillin Susceptible S ≤ 2 R ≥ 4 0.25 S 1 S 0.5 S 0.5 S 0.5 S 1 S 1 S 0.25 S 0.25 S 0.25 S 0.25 S Vancomycin Susceptible S ≤ 2 I = 4-8 R ≥ 16 < 0.25 S <0.25 S <0.25 S <0.25 S <0.25 S <0.25 S <0.25 S <0.125 S <0.125 S <0.125 S <0.125 S S. aureus NRS241 Bacteria from purified cultures Bacteria
harvested from a positive blood culture bottle Drug Phenotype CLSI MIC interpretation Macrobroth MIC and interpretation ETGA MIC and interpretation Ribose-5-phosphate isomerase gsPCR MIC and interpretation ETGA MIC and interpretation gsPCR MIC and interpretation 4 hr 6 hr 22 hr 4 hr 6 hr 22 hr 4 hr 6 hr 4 hr 6 hr Oxacillin Resistant S ≤ 2 R ≥ 4 16 R 8 R 16 R > 16 R N/Aa 16 R >16 R 8 R 16 R 8 R 2 Sc (VME) Vancomycin Susceptible S ≤ 2 I = 4-8 R ≥ 16 < 0.25 S <0.25 S <0.25 S <0.25 S <0.25 S <0.25 S <0.25 S <0.25b S <0.25 S <0.25d S <0.25d S E. coli ATCC 25922 Bacteria from purified cultures Bacteria harvested from a positive blood culture bottle Drug Phenotype CLSI MIC interpretation Macrobroth MIC and interpretation ETGA MIC and interpretation gsPCR MIC and interpretation ETGA MIC and interpretation gsPCR MIC and interpretation 4 hr 6 hr 22 hr 4 hr 6 hr 22 hr 4 hr 6 hr 4 hr 6 hr Ciprofloxacin Susceptible S ≤ 1 I = 2 R ≥ 4 0.008 S 0.016 S 0.016 S 0.031 S 0.016 S 0.016 S 0.031 S 0.008 S 0.008 S 0.004 S 0.008 S Tetracycline Susceptible S ≤ 4 I = 8 R ≥ 16 1 S 0.5 S 0.5 S 1 S 1 S 1 S 1 S 0.5 S 0.5 S 0.25 S 0.5 S All MIC values are in units of μg/mL.
Results are summarized in figure 4. As shown above, LSplex of S. aureus DNA allowed unambiguous species identification and discrimination from coagulase negative Staphylococci. Hybridization profiles of LSplex products Eltanexor ic50 corresponded very well with the expected hybridization profiles from genomic DNA (not shown). Amplified S. epidermidis DNA hybridized specifically selleck chemicals to S. epidermidis capture probes and showed no cross-hybridizations with S. aureus capture probes as well as with capture
probes of other coagulase negative staphylococci. Similar results were obtained with LSplex products of S. pneumonia DNA leading to clear-cut species identification and differentiation from all other Streptococci species. LSplexed E. faecalis DNA displayed high specificity to probes of E. faecalis, showing no cross hybridization with
the closely related species E. faecium. The same was observed in hybridization experiments with P. mirabilis DNA. Notably, LSplex products of 10 ng C. albicans DNA produced highly specific signals, with 4 to 5-times greater fluorescence intensity than those produced by 2 μg of genomic DNA. Figure 4 Specific detection of microbial DNA by LSplex amplification. Hybridization profiles generated selleck screening library by analysis of LSplex amplified products shown as columns (S. aureus, E. coli, S. pneumonia, E. faecalis, P. mirabilis, S. epidermidis, K. pneumoniae, C. albicans and P. aeruginosa). Each row represents an individual capture probe of the microarray, grouped by species or genus specific regions (see Additional Axenfeld syndrome file 2) as indicated in the left column. The boxes represent the positive hybridization signal of bacterial DNA (in colour) or absence of hybridisation (in white) with individual capture probes. Application of LSplex for microbiological diagnostics In order to demonstrate benefits of LSplex for the microarray-based detection of pathogens in clinical specimens we analysed cotton swabs taken from patients with superficial wounds. Such swabs represent one of the most frequent materials
processed by microbiological diagnostics. Swabs from superficial wounds contain one or more pathogens, normal skin flora and few human cells. The number of bacteria on swabs is usually low, so that time consuming amplification via subculture on microbiological media is required. DNA was isolated from three swabs taken from the same patient. DNA preparations were pooled and divided into two samples of approximately 20 ng each. One sample was subjected to LSplex (800 primer pairs). Other labeled directly prior to hybridization with the microarray. A typical hybridization pattern is depicted in figure 5. The directly labeled DNA hybridized only with 16S RNA probes (positive controls) indicating the presence of bacterial DNA in the sample (Fig. 5).
Twelve suckling mice were used for the repeat of attachment assay. Assay of CT production by GM1-ELISA CT production in culture supernatants was estimated in V. cholerae strains (N16961, N169-dtatABC, and N169-dtatABC-cp) incubated with AKI media (containing 1.5% Bacto peptone, 0.4% yeast extract-Difco, check details 0.5% NaCl and 0.3% NaHCO3), cultured at 37°C for 4 h in a stationary test tube and then for 16 h in a shaken flask, and measured by GM1-ELISA . In our study, the medium used for all cultures was AKI with 0.3% sodium
bicarbonate. To determine CT production, the strains incubated under static conditions for 4 h at 37°C were poured into flasks with a 20-fold greater volume than the tubes to continue growth at 37°C for 18 h with shaking at 220 rpm. All culture supernatants were concentrated 10-fold with PEG6000. A standard curve was generated using the purified B subunit of CT. As a second antibody, the monoclonal antibody against the B subunit of CT was added. Color intensity was measured at 492 nm in an ELISA reader (Bio-Rad). Three independent triplicate repeats were done for each strain. Transcription analysis of the ctxB gene in N16961 and N169-dtatABC cells The overnight cultures
of N16961 and N169-dtatABC cells were re-cultured to OD600 1.0 with fresh LB, and then 1:100 dilutions were transferred PR 171 into AKI medium. The medium used for all cultures was AKI complemented with 0.3% sodium bicarbonate. To determine the ctxB transcription levels, the strains incubated under still conditions for 4 h at 37°C find more were poured into flasks with a 20-fold greater volume than the tubes to continue growth at 37°C for 18 h with shaking at 220 rpm. The RNeasy Mini Kit (Qiagen) was used to extract total RNA from 1 ml of bacterial cultures. The RNase-free DNase set Kit (Qiagen) was used to eliminate
DNA. RNA samples were diluted to 1 ng/μl in order to obtain the template for RT-PCR after quantification. Primers 5′-CGC ATG AGG CGT TTT ATT ATT C-3′ and 5′-AAA GCG ATT GAA AGG ATG AAG G-3′ were used to amplify ctxB gene. The housekeeping gene thyA (primers 5′-ACA TGG GAC GCG TGT ATG G-3′ and 5′-ATA TGA CCA CCA TCA GGC TTA GC-3′) and 16S-rDNA (primers 5′-TTG ACA TCC AGA GAA TCT AGC GG-3′ and 5′-TTA ACC CAA CAT TTC ACA ACA CGA-3′) were selected as the references. RNA extraction and RT-PCR quantification were done in triplicate for each strain. 2-ΔΔCt method was used to calculate the Ct difference of ctxB between N16961 and N169-dtatABC, with the SB202190 existence of the control genes.
In keeping with the recognition of Shigella spp. as human-adapted pathovar of E. coli, all isolates were identified as E. coli by biochemical tests. Culture-based analysis and qPCR demonstrated AP26113 cell line presence of shiga-like-toxin producing E. coli (STEC) in both healthy and infected animals. Three out of eleven E. coli isolates were found to carry genes coding for SLT-1 or SLT-II. Moreover, SLT-genes were consistently
detected by qPCR in samples from metritic cows; STEC accounted for about 1 – 10% of the total E. coli population. SLT production causes diarrhoea in calves , but the role of STEC in the pathogenesis of metritis in adult animals warrants further clarification. Bacilli are present in the environment and they frequently contaminate the bovine uterine lumen . However, pediococci have not yet been described as part of the bovine vaginal microbiota. The genus Pediococcus is closely related to the genus Lactobacillus. Pediococci produce antimicrobial compounds such as organic acids, hydrogen peroxide, and antimicrobial peptides such as pediocin AcH/PA-1 . Ped. acidilactici is a food fermenting organism  but was also isolated from the
gastrointestinal tract of poultry, ducks, and sheep[22–24]. Pediocin AcH/PA-1 producing strains have been isolated from human infant faeces . The synthesis of pediocin AcH/PA-1 was initially described for the strains Ped. acidilactici PAC1.0 and Ped. acidilactici H, but synthesis has also been observed in other Doramapimod purchase Ped. acidilactici strains as well as Lactobacillus plantarum WHE92, Pediococcus parvulus ATO34, and ATO77 [26–28]. Pediocin AcH/PA-1 production is a plasmid-borne trait . The pediocin AcH/PA-1 operon consists of pediocin AcH/PA-1 gene (pedA/papA), a BACE inhibitor specific immunity gene (papB),
and genes responsible for processing and secretion (papC and papD) . In keeping with prior reports on pediocin activity , pediocin was not active against E. coli, the dominant organisms in the vaginal microbiota of infected animals. Pediocin producing isolates characterized in this study harboured the pediocin AcH/PA-1 operon, and qPCR analysis consistently detected the operon in both prepartum and postpartum vaginal samples. Bacteriocin formation is increasingly recognized as an important trait of probiotic cultures . Studies on the isolation of bacteriocin-producing ZD1839 in vivo lactic acid bacteria from the human vagina demonstrated their antimicrobial activities against human vaginal pathogens [33, 34]. Bacteriocin-producing Lactobacillus strains inhibited vaginal pathogens including Gardnerella vaginalis and Pseudomonas aeroginosa. Although bovine vaginal microbiota have much lower total cell counts and lactobacilli populations in comparison to the human vaginal microbiota [16, 36], bacteriocin such as pediocin may influence the microbial ecology in the reproductive tract of dairy cattle if bacteriocin-producing lactic acid bacteria are administered in high numbers.
This pathway utilizes approximately 15% of the cell’s ATP requirement  for
the production of glutamine and its activity is, therefore, strictly regulated at both transcriptional and post-translational levels in order to prevent energy wastage (see Figure 1A). Figure 1 Assimilation of nitrogen by (A) GS and GOGAT; (B) NADP + – dependant-glutamate dehydrogenase (GDH1) and NAD + -dependant glutamate dehydrogenase (GDH2). Under conditions of nitrogen excess, glutamine selleck synthetase activity is reduced via adenylylation by the adenylyltransferase GlnE [3, 4] and under these conditions, the low ammonium affinity glutamate dehydrogenase (GDH) pathway plays a major assimilatory role with a comparatively low associated energy cost . GDH enzymes catalyse the reversible amination of α-ketoglutarate to form glutamate (see Figure 1B) with concomitant reduction Selleck EPZ5676 of NAD(P)H. They also serve as metabolic branch enzymes
as the GDH enzymes are involved in anapleurotic BIBW2992 cost processes which regulate the flux of intermediates such as α-ketoglutarate between the Krebs cycle and nitrogen metabolism . The GDH enzymes identified in prokaryotes usually function with either NADP+ (EC 18.104.22.168) or NAD+ (EC 22.214.171.124) as co-factors whilst in higher eukaryotes the enzymes have dual co-factor specificity (EC 126.96.36.199). NADP+-specific enzymes are normally involved in the assimilation of nitrogen via amination of α-ketoglutarate  and may be transcriptionally
regulated by a variety of growth conditions, including carbon and nitrogen limitation [8–11]. In contrast, NAD+-specific GDH enzymes are thought to be largely involved in glutamate catabolism (deamination) [12–14] and do not appear to be regulated in response to ammonium limitation [15, 16]. GDH enzymes described to date are oligomeric structures and can be grouped into three subgroups according to subunit Thymidine kinase composition. Many NADP+- and NAD+-GDH enzymes from a number of organisms are hexameric structures made up of subunits that are approximately 50 kDa in size . The second GDH class comprise NAD+-specific GDH enzymes with tetrameric structures whose subunits have a molecular mass of approximately 115 kDa . Recently, a third class of oligomeric NAD+-specific GDH enzymes was defined whose subunits are approximately 180 kDa in size [18–20]. Information regarding nitrogen metabolism and its regulation in the mycobacteria is relatively limited. Glutamine synthetase (encoded by glnA1) has traditionally formed an isolated focal point of study with regard to nitrogen metabolism in the mycobacteria as it has been associated with Mycobacterium tuberculosis virulence and pathogenicity [21, 22]. It has previously been demonstrated that GS from pathogenic mycobacterial species such as M. tuberculosis and M.