The PET tracer 5-([11C]methyloxy)-L-tryptophan (5-(11)CMTP) was prepared by nucleophilic fluorination and alkylation reaction via a two-step procedure in order to develop specific tumor probe. The biodistribution and microPET imaging of 5-(11)CMTP were executed. The results unveiled that the overall radiochemical yield with no decay correction was (14.6 ±7.2) %, the radiochemical purity was more than 95% and high uptake and long retention time of 5-(11)CMTP in liver, kidney and blood were observed but low uptake in brain and muscle were found, furthermore, high uptake of 5-(11)CMTP in tumor tissue was observed. It seems that 5-(11)CMTP will be a potential amino acid tracer for tumors imaging with PET.
Amino Acids ; Animals ; Neoplasms ; diagnostic imaging ; Positron-Emission Tomography ; Radioactive Tracers ; Tissue Distribution ; Tryptophan ; analogs & derivatives

Because of the concern about escape of antibiotic- or herbicide-resistant transgenes from transgenic crops, selectable marker genes from plant origin would be an alternative choice for plant transformation. In this study, a feedback-insensitive anthranilate synthase gene ( ASA2 ) cloned from a tobacco cell line was tested for Agrobacterium-mediated transformation of axis tissue of soybean mature embryo, with a tryptophan analogue 5-methyltryptophan (5-MT) as the selective agent. Southern blot analysis of the To transgenic lines confirmed the integration of the ASA2 gene into the soybean genome. Northern blot analysis showed the ASA2 gene was also expressed in the leave tissue, and the free tryptophan content in the leaf tissue of transgenic soybean was about 59% to 123% more than that in the wild type. PCR analysis of the T1 progeny showed that the transgene was inherited in a Mendelian fashion. All these results indicate that this feedback-insensitive ASA2 gene can be used as a selectable marker gene for plant transformation. This work also demonstrated that the ASA2 gene coding for the a-subunits from one plant (tobacco) can interact with the n-subunits of a heterologous plant (soybean) to form an active anthranilate synthase enzyme. The use of this feedback-insensitive gene as a novel selectable marker for plant transformation is also discussed.
Anthranilate Synthase ; genetics ; Feedback, Physiological ; Plants, Genetically Modified ; genetics ; Soybeans ; genetics ; Transformation, Genetic ; Tryptophan ; analogs & derivatives ; metabolism

OBJECTIVETo investigate the immunological characteristics of human tonsil mesenchymal stem cells (TMSCs).

METHODSHuman tonsil tissues were obtained from the children patients with chronic tonsillitis. TMSCs were separated, cultured, and were detected the expression profiles of HLA-I, HLA-II, CD80, CD86 by flow cytometry. The measurement of immunogenicity, the effect on phytohemagglutinin (PHA) induced peripheral blood mononuclear cell (PBMCs) proliferation and mixed lymphocytes reaction (MLR) were performed to identify the immunological characteristics of TMSCs. The co-cultures of TMSCs + PBMCs + PHA and TMSCs + MLR were established, respectively, and the concentration of kynurenine, which is the metabolin of indoleamine 2, 3-dioxygenase, in the culture supernatant were examined. Then we added 1-methyl-L-tryptophan into the co-culture of TMSCs + PBMCs + PHA and TMSCs + MLR, respectively, and tested the proliferation of PBMCs. Each experiment was repeated three times, and there were six samples in each group. Statistical significance was assessed by analysis of variance (ANOVA), and a P value less than 0.05 was considered statistically significant.

RESULTSTMSCs expressed HLA-I, were negative for HLA-II and co-stimulatory molecules CD80 and CD86. The stimulation index in the group of TMSCs + allogeneic PBMCs was 1.38 ± 0.26, whereas the stimulation index in the group of allogeneic PBMCs was 1.22 ± 0.28, and there was no significant difference between the two groups (P > 0.05), indicating that TMSCs could not initiate the proliferation of allogeneic PBMCs. The stimulation indexes in the group of TMSCs + allogeneic PBMCs + PHA were 1.49 ± 0.29 and 1.23 ± 0.22, respectively, whereas the stimulation index in the group of allogeneic PBMCs + PHA was 4.60 ± 0.81, and the difference between the two groups had a statistical significance (P < 0.05) suggesting that TMSCs could inhibit PHA-induced PBMCs proliferation. The stimulation indexes in the group of TMSCs + MLR were 1.29 ± 0.23 and 1.26 ± 0.27, respectively, however, the stimulation index in the group of MLR was 3.04 ± 0.66, and the difference between the two groups had a statistical significance (P < 0.05), demonstrating that TMSCs could suppress MLR-induced PBMCs proliferation. The levels of kynurenine were (26.0 ± 2.3) μmol/L and (23.5 ± 4.5) μmol/L in the culture of TMSCs + PBMCs + PHA and TMSCs + MLR, respectively, thus elevating significantly. After adding of 1-methyl-L-tryptophan, TMSCs-mediated-proliferation suppression of PBMCs restored to normal levels.

CONCLUSIONTMSCs possess low immunogenecity and immunosuppressive function, may be used in allogeneic transplantation.

Cell Proliferation ; Cells, Cultured ; Child ; Coculture Techniques ; Flow Cytometry ; Humans ; Immunosuppression ; Kynurenine ; analysis ; Leukocytes, Mononuclear ; Lymphocyte Culture Test, Mixed ; methods ; Mesenchymal Stromal Cells ; cytology ; immunology ; Palatine Tonsil ; cytology ; Tryptophan ; administration & dosage ; analogs & derivatives

The objective of this study was to investigate the expression and function of indoleamine 2, 3-dioxygenase (IDO) in leukemia. The IDO expressions in human acute monocyte leukemia (M(5)) and acute lymphocyte leukemia (ALL) were detected by immunofluorescence staining. Constructed leukemia mouse model was used to observe whether the IDO inhibitor, 1-methyl tryptophan (1-MT), has any effect in treating leukemia. The experimental group were fed with 1-MT solution every day while the mice in control group had no further treatment. The results showed that the average ratios of IDO expression were 29.4 +/- 11.2% in M(5) patients and 24.7 +/- 7.96% in ALL patients respectively. After statistical test, IDO expression level in leukemia cells was significantly higher than that of normal mononuclear cells. The tumor decreased gradually in mice treated with 1-MT. At the terminal point of the experiment (88 days after vaccination), the average survival time in the experimental group was 42.3 days while the mice in control group only lived 15.1 days in average, which difference was statistically significant (P < 0.05). Some of the leukemia mice in the experimental group long-term survived without tumor (more than three months after vaccination). It is concluded that human acute monocyte leukemia (M(5)) and acute lymphocyte leukemia (ALL) express IDO, and both can be treated by 1-MT in mice.
Adolescent ; Adult ; Animals ; Child ; Female ; Humans ; Indoleamine-Pyrrole 2,3,-Dioxygenase ; antagonists & inhibitors ; metabolism ; Leukemia L1210 ; drug therapy ; Leukemia, Biphenotypic, Acute ; drug therapy ; enzymology ; Leukemia, Monocytic, Acute ; drug therapy ; enzymology ; Male ; Mice ; Mice, Inbred DBA ; Middle Aged ; Tryptophan ; analogs & derivatives ; therapeutic use ; Young Adult

OBJECTIVETo investigate the effect of amino acid parenteral nutritional (PN) support on serum tryptophan and melatonin in non-small cell lung cancer (NSCLC) patients receiving chemotherapy.

METHODSSeventy-two patients with inoperable NSCLC were divided into three groups randomly: control group, 250 ml/d amino acids PN therapy group and 500 ml/d amino acids PN therapy group. The same NP (cisplatin + vinorelbine) chemotherapy was carried out in all the three groups. During three sessions of chemotherapy,amino acids PN therapy was given to the amino acids PN therapy groups. Serum tryptophan and melatonin concentration changes were assessed before and after chemotherapy.

RESULTSAfter chemotherapy the concentration of MT and Try were much lower than that before chemotherapy in the three group patients (P < 0.05). But the concentration of MT and Try in the PN group patients was higher than that in control group patients. The concentration of MT and Try in the 500 ml/d amino acid parenteral nutritional support group patients were significantly higher than that in the 250 ml/d group patients, the difference was significant (P < 0.05).

CONCLUSIONAmino acid parenteral nutritional support is beneficial to improve the lower concentration of serum MT and Try in NSCLC patients receiving chemotherapy, and a more significant effect can be achieved by the 500 ml/d amino acid parenteral nutritional support treatment.

Aged ; Amino Acids ; administration & dosage ; therapeutic use ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Carcinoma, Non-Small-Cell Lung ; blood ; drug therapy ; therapy ; Cisplatin ; administration & dosage ; Female ; Humans ; Lung Neoplasms ; drug therapy ; pathology ; therapy ; Male ; Melatonin ; blood ; Neoplasm Staging ; Parenteral Nutrition ; Treatment Outcome ; Tryptophan ; blood ; Vinblastine ; administration & dosage ; analogs & derivatives

Mesenchymal stem cells (MSCs) can inhibit T cell proliferation; however, the underlying mechanisms are not clear. In this study, we investigated the mechanisms of the immunoregulatory activity of MSCs on T cells. Irradiated MSCs co-cultured with either naive or pre-activated T cells in a mixed lymphocyte reaction (MLR) significantly suppressed T cell proliferation in a dose-dependent manner, irrespective of allogeneic disparity between responders and MSCs. Transwell assays revealed that the suppressive effect was primarily mediated by soluble factors that induced apoptosis. Splenocytes stimulated with alloantigen in the presence of the MSC culture supernatant (CS) produced a significant amount of IL-10, which was attributed to an increase in the number of IL-10 secreting cells, confirmed by an ELISPOT assay. The blockade of IL-10 and IL-10 receptor interaction by anti-IL-10 or anti-IL-10-receptor antibodies abrogated the suppressive capacity of MSC CS, indicating that IL-10 plays a major role in the suppression of T cell proliferation. The addition of 1-methyl-DL-tryptophan (1-MT), an indoleamine 2,3-dioxygenase (IDO) inhibitor, also restored the proliferative capacity of T cells. In conclusion, we demonstrated that soluble mediators from culture supernatant of MSCs could suppress the proliferation of both naive and pre-activated T cells in which IL-10 and IDO play important roles.
Animals ; Cell Proliferation ; Cells, Cultured ; Indoleamine-Pyrrole 2,3,-Dioxygenase/antagonists & inhibitors/metabolism ; Interleukin-10/*biosynthesis ; *Lymphocyte Activation ; Lymphokines/pharmacology ; Mesenchymal Stem Cells/cytology/*metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Receptors, Interleukin-10/metabolism ; T-Lymphocytes/cytology/*immunology/metabolism ; Tryptophan/analogs & derivatives/pharmacology

Mesenchymal stem cells (MSCs) can inhibit T cell proliferation; however, the underlying mechanisms are not clear. In this study, we investigated the mechanisms of the immunoregulatory activity of MSCs on T cells. Irradiated MSCs co-cultured with either naive or pre-activated T cells in a mixed lymphocyte reaction (MLR) significantly suppressed T cell proliferation in a dose-dependent manner, irrespective of allogeneic disparity between responders and MSCs. Transwell assays revealed that the suppressive effect was primarily mediated by soluble factors that induced apoptosis. Splenocytes stimulated with alloantigen in the presence of the MSC culture supernatant (CS) produced a significant amount of IL-10, which was attributed to an increase in the number of IL-10 secreting cells, confirmed by an ELISPOT assay. The blockade of IL-10 and IL-10 receptor interaction by anti-IL-10 or anti-IL-10-receptor antibodies abrogated the suppressive capacity of MSC CS, indicating that IL-10 plays a major role in the suppression of T cell proliferation. The addition of 1-methyl-DL-tryptophan (1-MT), an indoleamine 2,3-dioxygenase (IDO) inhibitor, also restored the proliferative capacity of T cells. In conclusion, we demonstrated that soluble mediators from culture supernatant of MSCs could suppress the proliferation of both naive and pre-activated T cells in which IL-10 and IDO play important roles.
Animals ; Cell Proliferation ; Cells, Cultured ; Indoleamine-Pyrrole 2,3,-Dioxygenase/antagonists & inhibitors/metabolism ; Interleukin-10/*biosynthesis ; *Lymphocyte Activation ; Lymphokines/pharmacology ; Mesenchymal Stem Cells/cytology/*metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Receptors, Interleukin-10/metabolism ; T-Lymphocytes/cytology/*immunology/metabolism ; Tryptophan/analogs & derivatives/pharmacology

YfiBNR is a recently identified bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) signaling system in opportunistic pathogens. It is a key regulator of biofilm formation, which is correlated with prolonged persistence of infection and antibiotic drug resistance. In response to cell stress, YfiB in the outer membrane can sequester the periplasmic protein YfiR, releasing its inhibition of YfiN on the inner membrane and thus provoking the diguanylate cyclase activity of YfiN to induce c-di-GMP production. However, the detailed regulatory mechanism remains elusive. Here, we report the crystal structures of YfiB alone and of an active mutant YfiB(L43P) complexed with YfiR with 2:2 stoichiometry. Structural analyses revealed that in contrast to the compact conformation of the dimeric YfiB alone, YfiB(L43P) adopts a stretched conformation allowing activated YfiB to penetrate the peptidoglycan (PG) layer and access YfiR. YfiB(L43P) shows a more compact PG-binding pocket and much higher PG binding affinity than wild-type YfiB, suggesting a tight correlation between PG binding and YfiB activation. In addition, our crystallographic analyses revealed that YfiR binds Vitamin B6 (VB6) or L-Trp at a YfiB-binding site and that both VB6 and L-Trp are able to reduce YfiB(L43P)-induced biofilm formation. Based on the structural and biochemical data, we propose an updated regulatory model of the YfiBNR system.
Amino Acid Sequence ; Bacterial Proteins ; chemistry ; genetics ; metabolism ; Binding Sites ; Biofilms ; Crystallography, X-Ray ; Cyclic GMP ; analogs & derivatives ; metabolism ; Dimerization ; Molecular Dynamics Simulation ; Molecular Sequence Data ; Mutagenesis ; Protein Structure, Quaternary ; Pseudomonas aeruginosa ; metabolism ; Sequence Alignment ; Tryptophan ; chemistry ; metabolism ; Vitamin B 6 ; chemistry ; metabolism