Notch pathway plays a novel and critical role in regulating responses of T and antigen-presenting cells in aGVHD

Graft-versus-host disease (GVHD) induced by host antigen-presenting cells (APCs) and donor-derived T cells remains the major limitation of allogeneic bone marrow transplantation (allo-BMT). Notch signaling pathway is a highly conserved cell-cell communication that is important in T cell development. Recently, Notch signaling pathway is reported to be involved in regulating GVHD. To investigate the role of Notch inhibition in modulating GVHD, we established MHC-mismatched murine allo-BMT model. We found that inhibition of Notch signaling pathway by γ-secretase inhibitor in vivo could reduce aGVHD, which was shown by the onset time of aGVHD, body weight, clinical aGVHD scores, pathology aGVHD scores, and survival. Inhibition of Notch signaling pathway by DAPT ex vivo only reduced pathology aGVHD scores in the liver and intestine and had no impact on the onset time and clinical aGVHD scores. We investigated the possible mechanism by analyzing the phenotype of host APCs and donor-derived T cells. Notch signaling pathway had a broad effect on both host APCs and donor-derived T cells. The expressions of CD11c, CD40, and CD86 as the markers of activated dendritic cells (DCs) were decreased. The proliferative response of CD8+ T cell decreased, while CD4⁺ Notch-deprived T cells had preserved expansion with increased expressions of CD25 and Foxp3 as markers of regulatory T cells (Tregs). In conclusion, Notch inhibition may minimize aGVHD by decreasing proliferation and activation of DCs and CD8⁺ T cells while preserving Tregs expansion.     

Application of the phosphomannose-isomerase/mannose selection system in the Agrobacterium-mediated transformation of Lonicera hypoglauca Miq.

Journal of Plant Biochemistry and Biotechnology - The dried buds of Lonicera hypoglauca Miq. have antipyretic, antidotal and anti-inflammatory properties and as Flos lonicerae are widely used in...     

Reaction mechanism of surfactant‐sensitized chemiluminescence of bis(2,4,6‐trichlorophyenyl) oxalate and hydrogen peroxide induced by gold nanoparticles

The chemiluminescence (CL) of bis(2,4,6‐trichlorophyenyl) oxalate with hydrogen peroxide in the present of cationic surfactant and gold nanoparticles was studied. The CL emission was obviously enhanced in the presence of surfactant at a suitable concentration, with a synergetic catalysis effect exhibited. Different sizes of gold nanoparticles (15 and 50 nm) showed different effects on CL intensity. Mechanisms of the CL reaction and sensitization effect are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Pre‐copulation intervals,copulation frequencies,and initial progeny sex ratios in two biotypes of whitefly,Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge.     

Mechanism of neurotensin depolarization of rabbit colonic smooth muscle

The aims of this study were (1) to measure the effect of neurotensin on the membrane potential of circular muscle of the distal colon of the rabbit and (2) to determine the mechanism by which neurotensin affects the membrane potential of this tissue. The membrane potential was measured with microelectrodes placed intracellularly and the double sucrose gap. Neurotensin (10(-11) M to 10(-7) M) dose-dependently decreased the membrane potential. The maximum decrease in membrane potential occurred with 10(-9) M neurotensin. The ED50 of neurotensin depolarization of the membrane potential was 0.87 +/- 0.33 X 10(-10) M. The frequency of the slow waves was unchanged after neurotensin. The voltage response to a constant current pulse decreased as the concentration of neurotensin increased. The amplitude of the voltage response after a 0.6 microA current pulse decreased by 6 +/- 0.5 mV after neurotensin (10(-7) M) compared to the Krebs control (P less than 0.05). Decreasing the [Na+]o to 0-23 mM did not affect the decrease in membrane potential after neurotensin. However, perfusion with a test solution containing no added Ca2+ or verapamil (10(-5) M) inhibited neurotensin depolarization of the tissue. Evidence was found that neurotensin depolarizes colonic circular smooth muscle, and the decrease in membrane potential is associated with an increase in conductance which is dependent on influx of Ca2+.     

Postnatal changes in enzyme activities of rat myocardial adenine nucleotide catabolic pathway

Three catabolic enzymes, 5'-nucleotidase (5'NT), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP) and one anabolic enzyme, myokinase (MK) involved in adenine nucleotide (AN) metabolism were studied in myocardium from 4 to 105 day old rats. The specific enzyme activities (nmoles/min/mg protein) at day 4 were 35.3 for 5'NT, 28.4 for ADA, 43.3 for PNP, and 5 X 10(3) for MK. At day 7, 5'NT, activities rose to 450%; PNP and ADA 150%; and MK 120%; of the day 4 level. The activities of the three catabolic enzymes were elevated for one or two weeks then declined rapidly. By day 34, they were slightly above the adult values. MK activity displayed a different time course. It continued to increase slowly with age after the initial surge. Compared to the adult heart, the total activities of these catabolic enzymes in the one- to three-week-old heart were 30% to 220% higher. This transient elevation in AN catabolic enzyme activities may be related to active DNA synthesis and cell proliferation occurred in the rat myocardium during the same period.     

Association of Epstein-Barr virus early antigen diffuse component and virus-specified DNA polymerase activity.

The role of Epstein-Barr virus (EBV) early antigen diffuse component (EA-D) and its relationship with EBV DNA polymerase in EBV genome-carrying cells are unclear, EBV-specified DNA polymerase was purified in a sequential manner from Raji cells treated with phorbol-12,13-dibutyrate and n-butyrate by phosphocellulose, DEAE-cellulose, double-stranded DNA-cellulose, and blue Sepharose column chromatography. Four polypeptides with molecular masses of 110,000, 100,000, 55,000, and 49,000 daltons were found to be associated with EBV-specified DNA polymerase activity. A monoclonal antibody which could neutralize the EBV DNA polymerase activity was prepared and found to recognize 55,000- and 49,000-dalton polypeptides. An EA-D monoclonal antibody, R3 (G. R. Pearson, V. Vorman, B. Chase, T. Sculley, M. Hummel, and E. Kieff, J. Virol. 47:183-201, 1983), was also able to recognize these same two polypeptides associated with EBV DNA polymerase activity. It was concluded that EBV EA-D polypeptides, as identified by R3 monoclonal antibody, are critical components of EBV DNA polymerase.     

Differential Responsiveness in Zonal Growth of Cocklebur Seed Axes to CO2, C2H4, O2 and Respiration Inhibitors

The axial growth of de-coated cocklebur (Xanthium pennsylvanicumWallr.) seeds, whose axes were divided into 4 zones, was examinedin relation to the temperature-dependent shift of the effectof C₂H₄ on germination. At 23?C, where both C₂H₄ and CO₂ stimulatedgermination, CO₂ promoted the axial growth at the radicle tipzone, whereas C₂H₄ promoted growth in the proximal portion ofthe axis. At 33?C, C₂H₄ inhibited germination, and stronglysuppressed the growth at the radicle tip, whereas the effectof CO₂ did not change. The inhibition of growth at the radicletip zone was alleviated by O₂ enrichment, which also reversedthe inhibition of germination. It is thus apparent that thetemperature-dependent shift of the action of C₂H₄ is associatedwith a temperature-dependent responsiveness of the radicle tipzone to C₂H₄. Growth of the radicle tip zone was sensitive toNaN₃, whereas the proximal portion was sensitive to benzohydroxamicacid, an inhibitor of alternative respiration, suggesting thatthere may be an increase in the operation of the alternativerespiration path along a gradient of axial tissue from the tiptowards the cotyledonary side. The effects of CO₂ and C₂H₄ arediscussed in relation to the different respiratory activitiesin each axial zone of cocklebur seeds. (Received May 9, 1986; Accepted November 6, 1986)