51
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Zhang J, Liu G, Guo C, He Y, Li Z, Ning G, Shi X, Bao M. The FLOWERING LOCUS T orthologous gene of Platanus acerifolia is expressed as alternatively spliced forms with distinct spatial and temporal patterns. PLANT BIOLOGY (STUTTGART, GERMANY) 2011; 13:809-20. [PMID: 21815986 DOI: 10.1111/j.1438-8677.2010.00432.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The FLOWERING LOCUS T (FT) protein is a likely component of the 'florigen' signal that plays a crucial role in regulating the transition from vegetative to reproductive growth. Here, we report the isolation of full-length cDNAs and the corresponding genomic clones encoding orthologous FT proteins (PaFT) of London plane (Platanus acerifolia Willd). Two genes with high sequence identity were isolated (PaFT1-2), but 34 different transcript products were identified, comprising 21 splice forms produced by alternative splicing of the PaFT pre-mRNAs. Expression of the alternative splicing forms of PaFT varied according to tissue type and developmental stage. PaFT transcripts were detected throughout adult trees, whereas in juvenile trees they were only detected in dormant sub-petiolar buds. In adult trees, levels of the various alternative splicing PaFT forms were related to flower development stage and tree dormancy. Ectopic expression of the archetypal splice form of PaFT-A in tobacco and Arabidopsis developed multiple altered phenotypes, notably early flowering and attenuation of apical dominance. The evidence in this study indicates that complex alternative processing of PaFT transcripts in P. acerifolia may be associated with multiple regulatory roles, including initiation of flowering, flower development, apical dominance, tree dormancy and dormancy release.
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52
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Liu J, Fang PH, Dibs S, Hou Y, Li XF, Zhang S, Tao H, Zhang J, Li L, Ran Y, Chen J, Li N, Feng L, Hui R, Pu J, Bao M, Tan T, Yu S, Chen K, Huang C. CSPE Best Abstract Award Session. Europace 2011. [DOI: 10.1093/europace/euq491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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53
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Lauterbach JH, Bao M, Joza PJ, Rickert WS. Free-base nicotine in tobacco products. Part I. Determination of free-base nicotine in the particulate phase of mainstream cigarette smoke and the relevance of these findings to product design parameters. Regul Toxicol Pharmacol 2010; 58:45-63. [PMID: 20621585 DOI: 10.1016/j.yrtph.2010.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 05/16/2010] [Accepted: 05/18/2010] [Indexed: 11/24/2022]
Abstract
The free-base nicotine (FBN) content of mainstream cigarette smoke (MSS) has been discussed in the peer-reviewed literature and popular press. It has been alleged that manufacturers adjust product design features to increase the percentage of total nicotine (TN) in the MSS gas-vapor phase that is unprotonated [P(g)(,nic)(%)] and/or the fraction of nicotine in the MSS total particulate matter (TPM) that is unprotonated (FBN/TN). Our research showed the Health Canada Intensive smoking conditions negated the effects of blend and cigarette design features reported to raise the pH of TPM collected under ISO or US FTC conditions. Our research also showed that when additive-free Canadian cigarettes were smoked under ISO conditions, the FBN/TN ratio increased as the tar/nicotine ratio decreased. Our findings are in line with other studies that have questioned allegations of a relationship between use of ammonia and its compounds as tobacco additives and amounts of unprotonated nicotine in MSS. In addition, the experimental work demonstrated how use of solid-phase microextraction to estimate FBN can yield erroneously high results due to improper conditioning and/or smoking of the cigarettes. Our research showed that there is no longer any scientific support for regulators to require smoke pH and FBN determinations on cigarette products.
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54
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Bao M, He B, Yang L, Rios C, Engel S. Perceptual learning can increase feed-forward neural response in early visual cortex. J Vis 2010. [DOI: 10.1167/9.8.867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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55
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Engel S, Zhang P, Bao M, Kwon M, He S. Effects of orientation specific visual deprivation in adults measured using altered reality. J Vis 2010. [DOI: 10.1167/9.8.848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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56
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Bao M, Zhang P, Engel S. Adaptation effects that gain strength over 8 hour induction periods. J Vis 2010. [DOI: 10.1167/10.7.1364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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57
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Engel S, Zhang P, Bao M. Adaptation to low signal to noise decreases visual sensitivity. J Vis 2010. [DOI: 10.1167/10.7.1126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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58
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Zhang P, Bao M, He S, Engel S. Long-term orientation-specific contrast reduction reveals plasticity of mechanisms of contrast appearance. J Vis 2010. [DOI: 10.1167/8.17.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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59
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Ligero P, Villaverde JJ, Vega A, Bao M. Pulping cardoon (Cynara cardunculus) with peroxyformic acid (MILOX) in one single stage. BIORESOURCE TECHNOLOGY 2008; 99:5687-5693. [PMID: 18039568 DOI: 10.1016/j.biortech.2007.10.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 10/11/2007] [Accepted: 10/11/2007] [Indexed: 05/25/2023]
Abstract
In this work, depithed cardoon stalk (Cynara cardunculus) has been used with the objective of obtaining bleachable pulps. The material, once properly prepared, was subjected to one-step peroxyformic acid delignification. In order to study the process, a face-centred second order factorial design was developed which allowed the determination of the influences of four variables: concentrations of formic acid and hydrogen peroxide in the cooking liquor and the time and temperature of the treatment. Empirical mathematical models have been obtained which predict the yield, kappa index, residual lignin content, and viscosity of the pulps. These models demonstrate that in general the delignification was extensive, producing pulps with kappa indexes less than 25 in the majority of cases, with good yields in the range of 45-60%. However, the pulps seem to have been degraded in the reaction media, as can be deduced from the low viscosity values found: 260-520 mL/g.
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60
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Carano R, Li Y, Bao M, Li J, Berry L, Ross J, Kowalski J, French D, Dugger D, Schwall R, Wang Y, Fei D, Moseley SL, Filvaroff EH. Effect of anti-TGF-beta antibodies in syngeneic mouse models of metastasis. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2004; 4:377-8. [PMID: 15758268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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61
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Jamali R, Bao M, Arnqvist HJ. IGF-I but not insulin inhibits apoptosis at a low concentration in vascular smooth muscle cells. J Endocrinol 2003; 179:267-74. [PMID: 14596678 DOI: 10.1677/joe.0.1790267] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Apoptosis of vascular smooth muscle cells (VSMCs) is of importance in the development of diabetic angiopathy. Our aim was to evaluate the effect of insulin and IGF-I on apoptosis in VSMCs. Rat aortic VSMCs were used and apoptosis was induced by serum starvation. As apoptotic markers we measured caspase-3 activity, histone-associated DNA fragments by ELISA and nuclear morphology by DAPI (4',6-diamidino-2-phenylindole) staining. Phosphorylation of IGF-I receptors was evaluated by Western blot. Serum starvation had increased caspase-3 activity even after 3 h. The highest activity was found after 3-12 h. IGF-I 10(-9 )M inhibited serum starvation-induced caspase-3 activity with a maximal effect after 12 h. When studied after starvation for 12 h, significant inhibitory effects on caspase-3 were found at IGF-I concentrations of 10(-8)-10(-7) M (P<0.01) and at an insulin concentration of 10(-6 )M (P<0.01). DNA fragmentation was detected by ELISA after 24 h and chromatin condensation and nuclear fragmentation by DAPI staining after 24 and 48 h respectively. IGF-I dose-dependently reduced apoptosis evaluated by ELISA, reaching a maximal effect at 10(-9) M. Insulin reduced apoptosis but the effect was weaker and a higher concentration was needed. IGF-I (10(-8 )M) and insulin at a very high concentration (10(-6) M) phosphorylated IGF-I receptors. Taken together, IGF-I and insulin have antiapoptotic effects on VSMCs but the effect of insulin is only found at high unphysiological concentration.
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MESH Headings
- Animals
- Aorta
- Apoptosis/drug effects
- Blotting, Western/methods
- Caspase 3
- Caspases/analysis
- Cells, Cultured
- Enzyme-Linked Immunosorbent Assay/methods
- Insulin/pharmacology
- Insulin-Like Growth Factor I/pharmacology
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Phosphorylation
- Rats
- Rats, Sprague-Dawley
- Receptor, IGF Type 1/metabolism
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62
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Nanda N, Bao M, Clauser K, Phillips DR. CD84 signaling is a novel platelet stimulatory mechanism that occurs during platelet aggregation. J Thromb Haemost 2003. [DOI: 10.1111/j.1538-7836.2003.tb05250.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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63
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Liu G, Bao M. Adventitious shoot regeneration from in vitro cultured leaves of London plane tree (Platanus acerifolia Willd.). PLANT CELL REPORTS 2003; 21:640-644. [PMID: 12789413 DOI: 10.1007/s00299-002-0569-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2002] [Revised: 11/18/2002] [Accepted: 11/20/2002] [Indexed: 05/24/2023]
Abstract
Adventitious shoots were successfully regenerated from leaf explants of in vitro cultures of Platanus acerifolia Willd. The leaves of three clones (genotypes), designated as PH1, PH2 and PC, respectively, were wounded by three to four transverse cuts through the midvein and cultured on 26 media based on Murashige and Skoog (MS) basal medium, containing different concentrations of 6-benzylaminopurine (BAP) in combination with different concentrations of indole-3-butyric acid (IBA). The highest regeneration rate (>90%) and the largest number of shoot clumps per regenerating leaf (>4 shoot clumps/explant) were obtained with leaves of genotype PH2 cultured on MS basal medium supplemented with 17.76 microM BAP and 4.92 microM IBA. The other two genotypes, PH1 and PC, showed very low capability of shoot regeneration (<10%) on all the media tested. Shoots on leaf explants originated mainly from callus that developed around the cut end of petioles and along the cuts across the midvein. The regenerated shoots were micropropagated, rooted and transplanted to the soil successfully.
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64
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González-Pérez E, Via M, López-Alomar A, Esteban E, Valveny N, Bao M, Domingo E, Moral P. Lack of association between methylenetetrahydrofolate reductase (MTHFR) C677T and ischaemic heart disease (IHD): family-based association study in a Spanish population. Clin Genet 2002; 62:235-9. [PMID: 12220440 DOI: 10.1034/j.1399-0004.2002.620309.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effect of the C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene, traditionally associated with ischaemic heart disease (IHD), was assessed in a Spanish population. The transmission disequilibrium test (TDT) was used to determine a possible association in a sample of 101 trios of IHD patients. The distribution of MTHFR genotypes was similar in the IHD subjects and the parental group; the TT genotype was present in 14.9% of IHD patients, as compared to 15.2% in the parents. The frequency of the T allele was also similar in IHD cases and parents (39.6% vs. 42.4%; p = 0.649). The TDT confirmed that the observed transmission of the T allele did not deviate significantly from the expected one (chi2 = 0.743; p > 0.4). Our TDT analysis clearly demonstrates a lack of association between the T allele of the C677T mutation in MTHFR and cardiovascular artery disease, both for the general group and for different risk subgroups (smokers, hypertension, male sex, overweight and type A behaviour pattern) in the Spanish population.
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65
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Sun X, Bao M, Pan N, Cui X, Arnold DP, Jiang J. Infrared Spectra of Phthalocyanine and Naphthalocyanine in Sandwich-Type (Na)phthalocyaninato and Porphyrinato Rare-Earth Complexes. II. The Effects of Rare-Earth Ionic Size on the IR Characteristics of Naphthalocyaninein Bis(naphthalocyaninato) Rare-Earth Complexes. Aust J Chem 2002. [DOI: 10.1071/ch02080] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The infra-red (IR) spectroscopic data for a series of 28 homoleptic substituted bis(naphthalocyaninato) rare-earth complexes M(2,3-Nc*)2 [M = Y, La–Lu except Pm; H2Nc* = 3(4),12(13),21(22),30(31)-tetra(tert-butyl)-2,3- naphthalocyanine (H2TBNc) and 3,4,12,13,21,22,30,31-octa(dodecylthio)-2,3-naphthalocyanine (H2ODTNc)] have been collected with a resolution of 2 cm–1. These neutral sandwich complexes are radicals due to their composition (Nc*)2–MIII(Nc*)–, wherein the unpaired electron is delocalized over both macrocycles on the vibrational time scale. Compared to spectra obtained with low resolution, such as 4 cm–1, a larger number of vibrational modes could be distinguished. The IR spectra for M(ODTNc)2 are much simpler than those of M(TBNc)2, revealing the relatively higher symmetry of the former molecules. By analogy with bis(phthalocyaninato) rare-earth counterparts, the pyrrole stretching absorptions at 1314–1317 and 1323–1330�cm–1 for M(TBNc)2 and at 1316–1327 cm–1 for M(ODTNc)2 are assigned to the IR marker bands of the respective naphthalocyanine mono-anion radicals. These marker bands, together with those at 746–753 cm–1 assigned to C–H wagging, 1350–1355 cm–1 attributed to pyrrole stretchings, and 1389–1394 cm–1 due to naphthalene stretchings, have been found to shift slightly to higher energy along with the rare-earth contraction, clearly demonstrating the effect of rare-earth ionic radius.
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66
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Yang Y, Bao M, Yoon JW. Intrinsic defects in the T-cell lineage results in natural killer T-cell deficiency and the development of diabetes in the nonobese diabetic mouse. Diabetes 2001; 50:2691-9. [PMID: 11723051 DOI: 10.2337/diabetes.50.12.2691] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
T-cell-mediated autoimmune diabetes in nonobese diabetic (NOD) mice is closely associated with natural killer T (NKT)-cell deficiency. To determine whether intrinsic defects of the T-cell lineage contribute to the pathogenesis of the disease and NKT cell deficiency, we reconstituted the T-cell compartment in NOD.scid or BALB.scid mice with T-cells from NOD, nonobese diabetes-resistant (NOR), or AKR thymic precursor cells and examined the development of the NKT cell population. NKT cells developed well from AKR thymic precursor cells but not from other precursor cells in both recipient strains. Insulitis and diabetes developed only in the NOD.scid recipients of NOD or NOR precursor cells. When thymic precursor cells of beta2-microglobulin gene-deficient AKR mice, which have a deficient NKT population, were introduced into NOD.scid recipients, both CD4(+) and CD8(+) T-cell populations developed and the recipient mice developed insulitis and diabetes. We conclude that NKT cells originate from a T-cell-committed thymic precursor population and that the deficiency in the NKT cell population in NOD mice results from intrinsic defects within the T-cell lineage and plays a major role in the development of autoimmune diabetes in the presence of both the NOD thymus and antigen-presenting cells.
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MESH Headings
- Animals
- Antigen-Presenting Cells/immunology
- Autoimmune Diseases/immunology
- Autoimmune Diseases/pathology
- Cell Differentiation
- Cytokines/biosynthesis
- Diabetes Mellitus, Type 1/immunology
- Hematopoietic Stem Cell Transplantation
- Hematopoietic Stem Cells/cytology
- Hyaluronan Receptors/analysis
- Killer Cells, Natural/immunology
- Killer Cells, Natural/pathology
- Lymph Nodes/cytology
- Lymphocyte Count
- Mice
- Mice, Inbred AKR
- Mice, Inbred NOD
- Mice, SCID
- Receptors, Antigen, T-Cell, alpha-beta/analysis
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Interleukin-2/analysis
- Spleen/cytology
- T-Lymphocytes/immunology
- Thymus Gland/cytology
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67
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Phillips DR, Prasad KS, Manganello J, Bao M, Nannizzi-Alaimo L. Integrin tyrosine phosphorylation in platelet signaling. Curr Opin Cell Biol 2001; 13:546-54. [PMID: 11544022 DOI: 10.1016/s0955-0674(00)00250-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The beta 3 integrin cytoplasmic tyrosine (ICY) motif of alpha IIb beta 3 becomes tyrosine phosphorylated during platelet aggregation, causing Shc and myosin to interact with the beta-integrin cytoplasmic domain. Platelets from mice lacking beta 3 ICY motif tyrosines formed defective aggregates and poorly retracted clots, establishing integrin tyrosine phosphorylation as a key mediator of beta 3-integrin signals.
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68
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Ramakrishnan V, DeGuzman F, Bao M, Hall SW, Leung LL, Phillips DR. A thrombin receptor function for platelet glycoprotein Ib-IX unmasked by cleavage of glycoprotein V. Proc Natl Acad Sci U S A 2001; 98:1823-8. [PMID: 11172035 PMCID: PMC29341 DOI: 10.1073/pnas.98.4.1823] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glycoprotein (GP) V is a major substrate cleaved by the protease thrombin during thrombin-induced platelet activation. Previous analysis of platelets from GP V-null mice suggested a role for GP V as a negative modulator of platelet activation by thrombin. We now report the mechanism by which thrombin activates GP V -/- platelets. We show that proteolytically inactive forms of thrombin induce robust stimulatory responses in GP V null mouse platelets, via the platelet GP Ib--IX--V complex. Because proteolytically inactive thrombin can activate wild-type mouse and human platelets after treatment with thrombin to cleave GP V, this mechanism is involved in thrombin-induced platelet aggregation. Platelet activation through GP Ib-IX depends on ADP secretion, and specific inhibitors demonstrate that the recently cloned P2Y(12) ADP receptor (G(i)-coupled ADP receptor) is involved in this pathway, and that the P2Y(1) receptor (G(q)-coupled ADP receptor) may play a less significant role. Thrombosis was generated in GP V null mice only in response to catalytically inactive thrombin, whereas thrombosis occurred in both genotypes (wild type and GP V null) in response to active thrombin. These data support a thrombin receptor function for the platelet membrane GP Ib--IX--V complex, and describe a novel thrombin signaling mechanism involving an initiating proteolytic event followed by stimulation of the GP Ib--IX via thrombin acting as a ligand, resulting in platelet activation.
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69
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Bao M, Nakamura H, Yamamoto Y. Facile allylative dearomatization catalyzed by palladium. J Am Chem Soc 2001; 123:759-60. [PMID: 11456600 DOI: 10.1021/ja003718n] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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70
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Hong M, Zhang Q, Cao R, Bao M. [Syntheses, reactions and spectroscopic properties of cluster compounds containing ME4 (M = Mo, W; E = S, Se) units]. GUANG PU XUE YU GUANG PU FEN XI = GUANG PU 2000; 20:812-813. [PMID: 12938477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The synthetic reactions and spectroscopic studied of molybdenum (tungsten) -copper (silver, iron) -sulphur (selenium) cluster compounds, which can be prepared by the stepwise or unit construction reactions through the successive addition ML (L = Cl, Br, Sr, R2 etc) across six edges or four faces of ME4 (M = Mo, W; E = S, Se) tetrahedra, are described. A series of Mo (W)-Cu-S cluster compounds, (Et4N)2 [MCu2E4 (S2CNR2)2], (Et4N)2 [MCu2E3O (S2CNR2)2], [MCu2E4 (dppe)2] (dppe = bis (diphenylphosphine) ethane), (Et4N)2 [MCu3E4 (S2CNR2)4] (M = Mo, E = Se, R = Et (1a), R2 = C4H8 (1b), R = PhCH2 (lc)), (Et4N)2 [MCu4E4 (S2CNR2)4] (M = Mo, E = Se, R = Me (2)) (Et4N)2 [M2Cu4S8 (S2CNEt2)2], (Et4N)2 [M2Cu4S6O2- (S2CNC4H8)2], [Mo2Cu4S8 (dppm)2], [Mo2Cu4S6O2 (dppm)2], (dppm = bis (diphenylphosphine) -methane), (Et4N)4 (ME4Cu10L12) (M = Mo, E = Se, L = PhCH2S (3)), MoFe3Se4 (mu-R2NCS2)2 (R2NCS2)4 have been prepared and characterized by UV, IR and X-ray diffraction analyses.
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71
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Chung YH, Jun HS, Son M, Bao M, Bae HY, Kang Y, Yoon JW. Cellular and molecular mechanism for Kilham rat virus-induced autoimmune diabetes in DR-BB rats. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:2866-76. [PMID: 10946320 DOI: 10.4049/jimmunol.165.5.2866] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Kilham rat virus (KRV) causes autoimmune diabetes in diabetes-resistant BioBreeding (DR-BB) rats; however, the mechanism by which KRV induces autoimmune diabetes without the direct infection of beta cells is not well understood. We first asked whether molecular mimicry, such as a common epitope between a KRV-specific peptide and a beta cell autoantigen, is involved in the initiation of KRV-induced autoimmune diabetes in DR-BB rats. We found that KRV peptide-specific T cells generated in DR-BB rats infected with recombinant vaccinia virus expressing KRV-specific structural and nonstructural proteins could not induce diabetes, indicating that molecular mimicry is not the mechanism by which KRV induces autoimmune diabetes. Alternatively, we asked whether KRV infection of DR-BB rats could disrupt the finely tuned immune balance and activate autoreactive T cells that are cytotoxic to beta cells, resulting in T cell-mediated autoimmune diabetes. We found that both Th1-like CD45RC+CD4+ and cytotoxic CD8+ T cells were up-regulated, whereas Th2-like CD45RC-CD4+ T cells were down-regulated, and that isolated and activated CD45RC+CD4+ and CD8+ T cells from KRV-infected DR-BB rats induced autoimmune diabetes in young diabetes-prone BioBreeding (DP-BB) rats. We conclude that KRV-induced autoimmune diabetes in DR-BB rats is not due to molecular mimicry, but is due to a breakdown of the finely tuned immune balance of Th1-like CD45RC+CD4+ and Th2-like CD45RC-CD4+ T cells, resulting in the selective activation of beta cell-cytotoxic effector T cells.
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72
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Bao M, Hong M, Su W, Cao R. Bis(N,N-diethyl-1,1-diselenocarbamato-Se)selenium, [(Se2CNEt2)2Se]. Acta Crystallogr C 2000; 56:E219-20. [PMID: 15263160 DOI: 10.1107/s0108270100005497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2000] [Accepted: 04/10/2000] [Indexed: 11/10/2022] Open
Abstract
The polyseleno title compound, bis(N,N-diethylselenocarbamoyl) triselenide, [(Se(2)CNEt(2))(2)Se] or C(10)H(20)N(2)Se(5), is obtained from the disproportion of sodium N,N-diethyl-1,1-diselenocarbamate. An Se atom connects two N,N-diethyl-1,1-diselenocarbamate groups with Se-Se distances in the range 2.4500 (11)-2.8601 (12) A
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73
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Raas-Rothschild A, Cormier-Daire V, Bao M, Genin E, Salomon R, Brewer K, Zeigler M, Mandel H, Toth S, Roe B, Munnich A, Canfield WM. Molecular basis of variant pseudo-hurler polydystrophy (mucolipidosis IIIC). J Clin Invest 2000; 105:673-81. [PMID: 10712439 PMCID: PMC289169 DOI: 10.1172/jci5826] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Mucolipidosis IIIC, or variant pseudo-Hurler polydystrophy, is an autosomal recessive disease of lysosomal hydrolase trafficking. Unlike the related diseases, mucolipidosis II and IIIA, the enzyme affected in mucolipidosis IIIC (N-Acetylglucosamine-1-phosphotransferase [GlcNAc-phosphotransferase]) retains full transferase activity on synthetic substrates but lacks activity on lysosomal hydrolases. Bovine GlcNAc-phosphotransferase has recently been isolated as a multisubunit enzyme with the subunit structure alpha(2)beta(2)gamma(2). We cloned the cDNA for the human gamma-subunit and localized its gene to chromosome 16p. We also showed, in a large multiplex Druze family that exhibits this disorder, that MLIIIC also maps to this chromosomal region. Sequence analysis of the gamma-subunit cDNA in patients from 3 families identified a frameshift mutation, in codon 167 of the gamma subunit, that segregated with the disease, indicating MLIIIC results from mutations in the phosphotransferase gamma-subunit gene. This is to our knowledge the first description of the molecular basis for a human mucolipidosis and suggests that the gamma subunit functions in lysosomal hydrolase recognition.
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Kornfeld R, Bao M, Brewer K, Noll C, Canfield W. Molecular cloning and functional expression of two splice forms of human N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase. J Biol Chem 1999; 274:32778-85. [PMID: 10551838 DOI: 10.1074/jbc.274.46.32778] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have isolated and sequenced human cDNA and mouse genomic DNA clones encoding N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase (phosphodiester alpha-GlcNAcase) which catalyzes the second step in the synthesis of the mannose 6-phosphate recognition signal on lysosomal enzymes. The gene is organized into 10 exons. The protein sequence encoded by the clones shows 80% identity between human and mouse phosphodiester alpha-GlcNAcase and no homology to other known proteins. It predicts a type I membrane-spanning glycoprotein of 514 amino acids containing a 24-amino acid signal sequence, a luminal domain of 422 residues with six potential N-linked glycosylation sites, a single 27-residue transmembrane region, and a 41-residue cytoplasmic tail that contains both a tyrosine-based and an NPF internalization motif. Human brain expressed sequence tags lack a 102-base pair region present in human liver cDNA that corresponds to exon 8 in the genomic DNA and probably arises via alternative splicing. COS cells transfected with the human cDNA expressed 50-100-fold increases in phosphodiester alpha-GlcNAcase activity proving that the cDNA encodes the subunits of the tetrameric enzyme. Transfection with cDNA lacking the 102-base pair region also gave active enzyme. The complete genomic sequence of human phosphodiester alpha-GlcNAcase was recently deposited in the data base. It showed that our cDNA clone was missing only the 5'-untranslated region and initiator methionine and revealed that the human genomic DNA has the same exon organization as the mouse gene.
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Abstract
It was first reported in China that injection of a low dose of D-galactose into mice could induce changes which resembled accelerated aging. The aging model shows neurological impairment, decreased activity of anti-oxidant enzymes, and poor immune responses. However, the underlining mechanism remains largely unknown. D-galactose is a reducing sugar that can form advanced glycation endproducts (AGE) in vivo. To investigate the role of AGE in this aging model, a group of 5-month-old C57 mice were injected daily with D-galactose, D-galactose modified AGE-lysine (AGE-lysine), L-glucose, L-lysine, or control buffer for 8 weeks. Two additional groups were treated with the AGE formation inhibitor, aminoguanidine. The results show that D-galactose, L-glucose, and AGE-lysine treated mice had a significant increase in serum AGE levels, memory latency time and error rate, and skin hydroxyproline content. Similar to aged controls, these mice also had a significant decrease in motor activity, lymphocyte mitogenesis, interleukin-2 (IL-2) production, and superoxide dismutase (SOD) enzyme activity. The aminoguanidine treated D-galactose-injected mice, however, showed no significant changes in these parameters in comparison with young controls. These data indicate that D-galactose and L-glucose form AGEs in vivo and that elevated AGEs may accelerate the aging process. The fact that both D-galactose and AGE treated mice resemble aged mice suggests that advanced glycation, at least partially, accounts for the mechanism of this aging model.
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Bao M, Cao R, Su W, Hong M. (1,1-Dimercaptoethene-2,2-dicarbonitrilato- S, S')bis(triphenylphosphine)palladium(II) Diacetonitrile Solvate. Acta Crystallogr C 1998. [DOI: 10.1107/s0108270198006465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Kornfeld R, Bao M, Brewer K, Noll C, Canfield WM. Purification and multimeric structure of bovine N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase. J Biol Chem 1998; 273:23203-10. [PMID: 9722550 DOI: 10.1074/jbc.273.36.23203] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N-Acetylglucosamine-1-phosphodiester alpha-N-Acetylglucosaminidase (EC 3.1.4.45; phosphodiester alpha-GlcNAcase) catalyzes the second step in the synthesis of the mannose 6-phosphate determinant required for efficient intracellular targeting of newly synthesized lysosomal hydrolases to the lysosome. A partially purified preparation of phosphodiester alpha-GlcNAcase from bovine pancreas was used to generate a panel of murine monoclonal antibodies. The anti-phosphodiester alpha-GlcNAcase monoclonal antibody UC1 was coupled to a solid support and used to immunopurify the bovine liver enzyme 670,000-fold in two steps to apparent homogeneity with an overall yield of 14%. The purified phosphodiester alpha-GlcNAcase has a specific activity of 498 micromol of [3H]GlcNAc-alpha-phosphomannose-alpha-methyl cleaved per h per mg of protein using 0.5 mM [3H]GlcNAc-alpha-phosphomannose-alpha-methyl as substrate. The subunit structure of the enzyme was determined using a combination of analytical gel filtration chromatography, SDS-polyacrylamide gel electrophoresis, and amino-terminal sequencing. The data indicate that bovine phosphodiester alpha-GlcNAcase is a 272,000-Da complex of four identical 68,000-Da glycoprotein subunits arranged as two disulfide-linked homodimers. A soluble form of the enzyme, isolated from fetal bovine serum, showed the same subunit structure. Both forms of the enzyme reacted with a rabbit antibody raised to the amino-terminal peptide of the liver enzyme, suggesting that phosphodiester alpha-GlcNAcase is a type I membrane-spanning glycoprotein with its amino terminus in the lumen of the Golgi apparatus.
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Bao M, Elmendorf BJ, Booth JL, Drake RR, Canfield WM. Bovine UDP-N-acetylglucosamine:lysosomal-enzyme N-acetylglucosamine-1-phosphotransferase. II. Enzymatic characterization and identification of the catalytic subunit. J Biol Chem 1996; 271:31446-51. [PMID: 8940156 DOI: 10.1074/jbc.271.49.31446] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The kinetic properties of UDP-N-acetylglucosamine:lysosomal-enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) purified to homogeneity from lactating bovine mammary gland have been investigated. GlcNAc-phosphotransferase transferred GlcNAc 1-phosphate from UDP-GlcNAc to the synthetic acceptor alpha-methylmannoside, generating GlcNAc-1-phospho-6-mannose alpha-methyl, the structure of which was confirmed by mass spectroscopy. GlcNAc-phosphotransferase was active between pH 5.7 and 9.3, with optimal activity between pH 6.6 and 7.5. Activity was strictly dependent on Mg2+ or Mn2+. The Km for Mn2+ was 185 microM. The Km for UDP-GlcNAc was 30 microM, and that for alpha-methylmannoside was 63 mM. The enzyme was competitively inhibited by UDP-Glc, with a Ki of 733 microM. The 166-kDa subunit was identified as the catalytic subunit by photoaffinity labeling with azido-[beta-32P]UDP-Glc. Purified GlcNAc-phosphotransferase utilizes the lysosomal enzyme uteroferrin approximately 163-fold more effectively than the non-lysosomal glycoprotein ribonuclease B. Antibodies to GlcNAc-phosphotransferase blocked the transfer to cathepsin D, but not to alpha-methylmannoside, suggesting that protein-protein interactions are required for the efficient utilization of glycoprotein acceptors. These results indicate that the purified bovine GlcNAc-phosphotransferase retains the specificity for lysosomal enzymes as acceptors previously observed with crude preparations.
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Bao M, Booth JL, Elmendorf BJ, Canfield WM. Bovine UDP-N-acetylglucosamine:lysosomal-enzyme N-acetylglucosamine-1-phosphotransferase. I. Purification and subunit structure. J Biol Chem 1996; 271:31437-45. [PMID: 8940155 DOI: 10.1074/jbc.271.49.31437] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
UDP-N-acetylglucosamine:lysosomal-enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) catalyzes the initial step in the synthesis of the mannose 6-phosphate determinant required for efficient intracellular targeting of newly synthesized lysosomal hydrolases to the lysosome. The enzyme was partially purified approximately 30,000-fold by chromatography of solubilized membrane proteins from lactating bovine mammary glands on DEAE-Sepharose, reactive green 19-agarose, and Superose 6. The partially purified enzyme was used to generate a panel of murine monoclonal antibodies. The anti-GlcNAc-phosphotransferase monoclonal antibody PT18 was coupled to a solid support and used to immunopurify the enzyme approximately 480,000-fold to apparent homogeneity with an overall yield of 29%. The purified enzyme has a specific activity of 10-12 micromol of GlcNAc phosphate transferred per h/mg using 100 mM alpha-methylmannoside as acceptor. The subunit structure of the enzyme was determined using a combination of analytical gel filtration chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and amino-terminal sequencing. The data indicate that bovine GlcNAc-phosphotransferase is a 540,000-Da complex composed of disulfide-linked homodimers of 166,000- and 51,000-Da subunits and two identical, noncovalently associated 56,000-Da subunits.
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Kang J, Bao M, Liang J. [Determination of tuberculostearic acid for diagnosis of tuberculous meningitis with negative culture of tubercle bacillus]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 1995; 18:340-3, 382. [PMID: 8762491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Tuberculostearic acid, a structural component of Mycobacterium tuberculosis, was identified by gas chromatography in cerebrospinal fluid from 44 out of 59 patients with tuberculous meningitis. Tuberculostearic acid was found in the cerebrospinal fluid of 5 patients out of 112 with non-tuberculous meningitis or non-infectious disorders. The results showed the test had a sensitivity of 74.6% and a specificity of 95.9%. Detection of tuberculostearic acid in cerebrospinal fluid is a rapid, sensitive and specific test for tuberculous meningitis.
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Zhu L, Tan Z, Bao M. Application of the external perichondrium of the ala of the thyroid cartilage of the nondiseased side in laryngeal surgery. J Laryngol Otol 1994; 108:770-1. [PMID: 7964141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Since 1976, in our department, the external perichondrium of the ala of the thyroid cartilage of the nondiseased side has been successfully applied in repairing endolaryngeal defects and reconstructing the laryngeal wall in 22 cases. The postoperative result was good in the most cases.
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Bao M. [Postoperative monitoring of pulmonary artery pressure in children in congenital heart disease with pulmonary hypertension]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1993; 28:274-6. [PMID: 8258166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Bao M, Wong L, Ge L, Vavassori C, LaPorte R, Dorman J, Trucco M. 6.2-08 Does ASP-57 confer protection to IDDM in oriental populations as well as in caucasians? Hum Immunol 1989. [DOI: 10.1016/0198-8859(89)90696-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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