Intrinsic Activity and Stability of Bifunctional Human UMP Synthase and Its Two Separate Catalytic Domains, Orotate Phosphoribosyltransferase and Orotidine-5′-phosphate Decarboxylase

Human UMP synthase is a bifunctional protein containing two separate catalytic domains, orotate phosphoribosyltransferase (EC 2.4.2.10) and orotidine-5'-phosphate decarboxylase (EC 4.1.1.23). These studies address the question of why the last two reactions in pyrimidine nucleotide synthesis are catalyzed by a bifunctional enzyme in mammalian cells, but by two separate enzymes in microorganisms. From existing data on subunit associations of the respective enzymes and calculations showing the molar concentration of enzyme to be far lower in mammalian cells than in microorganisms, we hypothesize that the covalent union in UMP synthase stabilizes the domains containing the respective catalytic centers. Evidence supporting this hypothesis comes from studies of stability of enzyme activity in vitro, at physiological concentrations, of UMP synthase, the two isolated catalytic domains prepared by site-directed mutagenesis of UMP synthase, and the yeast ODCase. The two engineered domains have activities very similar to the native UMP synthase, but unlike the bifunctional protein, the domains are quite unstable under conditions promoting the dissociated monomer

Tunable optical property and zero-field splitting of transition metal adatom-graphene quantum dot systems

Graphene quantum dots (GQDs) with transition metal adatoms were analysed using a first principles approach aimed at finding novel optical materials. The optical properties of the systems that constitute GQDs with a size of 0.4-1.1 nm and five transition metals (Cr, Mo, Pd, Pt, and W) were investigated by time-dependent density functional theory. The HOMO-LUMO gaps, absorption spectra, zero-field splittings, and intersystem-crossing gaps are the main results. Unusual quantum dot size dependencies were found in the energy levels and absorption spectra that stem from extra confinement induced by the transition metal adatoms. Due to the molecular orbital hybridization between GQDs and transition metal adatoms, the major absorption peaks in the visible range could be achieved with a smaller diameter of graphene quantum dots that are relatively free from the influence of deformations. In addition, transition metal-induced magnetic effects were also confirmed by large zero-field splittings, which are negligible in pristine GQDs. The major absorption peaks are located near each red (1.59-1.98 eV), green (2.19-2.38 eV), and blue-violet (2.48-3.26 eV) spectral range, covering the entire visible spectrum, whereas the zero-field splitting mostly covers terahertz regions. These results suggest that the transition metal adatom-GQD systems are strong candidates for optical emission and absorption materials with excellent tunability over a wide spectral range.11Nsciescopu

Tunable Optical Absorption of Graphene Quantum Dots with Transition Metal Adatom

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IL7-Fc Enhances the Efficacy of Adoptive T Cell Therapy under Lymphopenic Conditions in a Murine Melanoma Model

Adoptive cell therapy (ACT) using tumor-reactive T cells is a promising form of immunotherapy to specifically target cancer. However, the survival and functional maintenance of adoptively transferred T cells remains a challenge, ultimately limiting their efficacy. Here, we evaluated the use of recombinant IL7-Fc in ACT. In a lymphopenic murine melanoma model, IL7-Fc treatment led to the enhanced inhibition of tumor growth with an increased number of adoptively transferred CD8+ T cells in tumor tissue and tumor-draining lymph nodes. Additionally, IL7-Fc further enhanced anti-tumor responses that were induced by recombinant human IL2 in the same mouse model. In contrast, in an immunocompetent murine melanoma model, IL7-Fc dampened the anti-tumor immunity. Further, IL7-Fc decreased the proliferation of adoptively transferred and immune-activated tumor-reactive CD8+ T cells in immunocompetent mice by inducing the massive expansion of endogenous T cells, thereby limiting the space for adoptively transferred T cells. Our data suggest that IL7-Fc is principally beneficial for enhancing the efficacy of tumor-reactive T-cells in lymphopenic conditions for the ACT

TotalPlex gene amplification using bulging primers for pharmacogenetic analysis of acute lymphoblastic leukemia

Genetic polymorphism among patients with acute lymphoblastic leukemia (ALL) is an important factor in the effectiveness and toxicity of anti-leukemic drugs. Genotyping of various polymorphisms that impact the outcome of anti-leukemic drug therapy (pharmacogenetics) presents an attractive approach for developing individualized therapy. We developed an easy and accurate method of analyzing multiple genes using a small amount of DNA, which we termed TotalPlex amplification. We used 16 pairs of specific bulging specific primers (SBS primers) for simultaneous amplification of 16 loci in a single PCR tube. Sixteen single nucleotide polymorphisms (SNPs) (CYP3A4*1B A>G, CYP3A5*3 G>A, GSTP1 313 A>G, GSTM1 deletion, GSTT1 deletion, MDR1 exon 21 G>T/A, MDR1 exon 26 C>T, MTHFR 677 C>T, MTHFR 1298 A>C, NR3C1 1088 A>G, RFC 80 G>A, TPMT 238 G>C, TPMT 460 G>A, TPMT 719 A>G, VDR intron 8 G>A, VDR FokI T>C) that have been implicated in the pharmacogenetics of ALL therapy were analyzed by TotalPlex amplification and SNP genotyping. We successfully amplified specific gene fragments using 16 pairs of primers in one PCR reaction tube with minimal spurious amplification products using TotalPlex amplification coupled to a multiplexed bead array detection system. The genotypes of 16 loci from 34 different genomic DNA (gDNA) samples derived using the TotalPlex system were consistent with the results of several standard genotyping methods, including automatic sequencing, PCR restriction fragment length polymorphism (RFLP) analysis, PCR, and allele-specific PCR (AS-PCR). Thus, the TotalPlex system represents a useful method of amplification that can improve the time, cost, and sample size required for high-throughput pharmacogenetic analysis of SNPs

Extracellular stimulation of VSIG4/complement receptor Ig suppresses intracellular bacterial infection by inducing autophagy

<p>VSIG4/CRIg (V-set and immunoglobulin domain containing 4) is a transmembrane receptor of the immunoglobulin superfamily that is expressed specifically on macrophages and mature dendritic cells. VSIG4 signaling accelerates phagocytosis of C3-opsonized bacteria, thereby efficiently clearing pathogens within macrophages. We found that VSIG4 signaling triggered by C3-opsonized <i>Listeria</i> (opLM) or by agonistic anti-VSIG4 monoclonal antibody (mAb) induced macrophages to form autophagosomes. VSIG4-induced autophagosomes were selectively colocalized with the intracellular LM while starvation-induced autophagosomes were not. Consistent with these results, the frequency of autophagosomes induced by infection with opLM was lower in VSIG4-deficient bone marrow-derived macrophages (BMDMs) than in WT BMDMs. Furthermore, when VSIG4 molecules were overexpressed in HeLa cells, which are non-macrophage cells, VSIG4 triggering led to efficient uptake of LM, autophagosome formation, and killing of the infected LM. These findings suggest that VSIG4 signaling not only promotes rapid phagocytosis and killing of C3-opsonized intracellular bacteria, as previously reported, but also induces autophagosome formation, eliminating the LM that have escaped from phagosomes. We conclude that VSIG4 signaling provides an anti-immune evasion mechanism that prevents the outgrowth of intracellular bacteria in macrophages.</p

Therapeutic plasma exchange in patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: The 10-year experience of a single center

Background: Therapeutic plasma exchange (TPE) has been used for the treatment of patients with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS). We report the 10-year treatment results along with the risk factors analyses. Methods: Retrospective analyses were performed on patients who were treated with TPE for TTP-HUS. Results: Fifty-two patients were included. Secondary causes were identified in 38 patients (73.1%). The others were classified as idiopathic. After a median five sessions of TPE, 26 patients (50.0%) achieved remission. Remission rate in patients with idiopathic and secondary TTP-HUS was 71.4 and 42.1%, respectively. Overall 30-day mortality rate was 34.6% and median overall survival was 5.2 months. Patients with hematopoietic stem cell transplantation-associated TTP-HUS did not respond and had poor overall survival. Males had a lower remission rate than females (P=0.009). Conclusions: TPE was an effective treatment in patients with idiopathic TTP-HUS. Treatment results were various according to etiology and gender

Comparative outcomes of reduced intensity and myeloablative allogeneic hematopoietic stem cell transplantation in patients under 50 with hematologic malignancies

We have conducted a direct comparison of the outcomes of reduced intensity and myeloablative conditioning in younger adults with hematological malignancies0.5x10(9)/L) occurred more rapidly in the reduced intensity group (median: 10 d; range: 0-21 d) than in the myeloablative group (median: 18 d; range: 11-38 d; p<0.0001). The incidence of grades 2-4 acute graft-vs.-host disease were similar between the reduced intensity and myeloablative groups, at 17% vs. 24% respectively (p=0.40). The cumulative incidence of day 100 non-relapse mortality was 18% in the reduced intensity group, and 21% in the myeloablative group (p=0.88). The overall two-yr survival rates were 43% in the reduced intensity group, and 35% in the myeloablative group (p=0.72). In conclusion, reduced intensity transplantation yielded outcomes comparable with those of myeloablative transplantation in patients under 50 with hematological malignancies

Pharmacogenetic analysis of pediatric patients with acute lymphoblastic leukemia: a possible association between survival rate and ITPA polymorphism.

Genetic polymorphisms are important factors in the effects and toxicity of chemotherapeutics. To analyze the pharmacogenetic and ethnic differences in chemotherapeutics, major genes implicated in the treatment of acute lymphoblastic leukemia (ALL) were analyzed. Eighteen loci of 16 genes in 100 patients with ALL were analyzed. The distribution of variant alleles were CYP3A4*1B (0%), CYP3A5*3 (0%), GSTM1 (21%), GSTP1 (21%), GSTT1 (16%), MDR1 exon 21 (77%), MDR1 exon 26 (61%), MTHFR 677 (63%), MTHFR 1298 (29%), NR3C1 1088 (0%), RFC1 80 (68%), TPMT combined genotype (7%), VDR intron 8 (11%), VDR FokI (83%), TYMS enhancer repeat (22%) and ITPA 94 (30%). The frequencies of single nucleotide polymorphisms (SNPs) of 10 loci were statistically different from those in Western Caucasians. Dose percents (actual/planned dose) or toxicity of mercaptopurine and methotrexate were not related to any SNPs. Event free survival (EFS) rate was lower in ITPA variants, and ITPA 94 AC/AA variant genotypes were the only independent risk factor for lower EFS in multivariate analysis, which was a different pharmacogenetic implication from Western studies. This study is the first pharmacogenetic study in Korean pediatric ALL. Our result suggests that there are other possible pharmacogenetic factors besides TPMT or ITPA polymorphisms which influence the metabolism of mercaptopurine in Asian populations