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.     

Therapeutic efficacy of Stephania tetrandra S. Moore for treatment of neovascularization of retinal capillary (retinopathy) in diabetes--in vitro study.

The present study was designed to examine therapeutic efficacy of the root extract of Stephania Tetrandra S. Moore (STMS) (traditional Chinese medicine; Han Fang Ji) for treatment of neovascularization of the retinal capillary (retinopathy) in streptozotocin (STZ)-induced diabetic rats (STZ diabetic rats) in culture. Recently we have established the culture system in which fetal bovine serum (FBS) in Dulbecco modified Eagle medium (DMEM) induced neovascularization of the retinal capillary and choroidal capillary in normal rats in culture. STZ diabetic rats showed more neovascularization of the retinal capillary and choroidal capillary than did normal rats in culture. In this study, the retinal tissue was removed for the posterior ocular region and cultured in DMEM containing FBS. The choroidal tissue of the posterior ocular region was also removed and cultured as an internal reference. Administration of STSM (0.91, 9.1 and 91 microg/ml) significantly suppressed neovascularization of the retinal capillary in both STZ diabetic rats and normal rats in a dose-dependent manner. Similar results were obtained with the choroidal capillary; administration of STSM suppressed neovascularization of the choroidal capillary in both STZ diabetic rats and normal rats. In order to determine the component of STSM inhibiting neovascularization of the retinal capillary, tetrandrine (a major chemical constituent of STSM) was administered and neovascularization of the retinal capillary was examined in culture. The effect of tetrandrine on the choroidal capillary was also examined as an internal reference. Administration of tetrandrine (0.1, 1.0 and 10 microM) suppressed neovascularization of the retinal capillary in both STZ diabetic rats and normal rats in a dose-dependent manner. Similar results were obtained with the choroidal capillary of both STZ diabetic rats and normal rats. We infer, therefore, that STSM has a direct effect on the retinal capillary of posterior ocular region and suppresses neovascularization of retinal capillary in STZ diabetic rats through the activation of tetrandrine. These results suggest that STSM may prevent for delay the progression of retinopathy in diabetic patients.     

Iron plaque enhances phosphorus uptake by rice (Oryza sativa) growing under varying phosphorus and iron concentrations

Both solution culture and pot experiments were performed to investigate (a) the effects of external Fe (II) concentrations and forms on the formation of iron plaque on the roots of rice (Oryza sativa) and subsequent P adsorption on iron plaque and shoot P concentrations and (b) the effects of soil moisture regimes on the formation of iron plaque and P adsorption on root surfaces and P accumulation in shoots. The results showed that iron plaque was significantly increased with increasing Fe²⁺ concentrations in the solution culture. The amounts of P adsorbed on the iron plaque were increased significantly with external Fe²⁺ concentrations. Although shoot P concentration was not significantly affected by Fe²⁺ treatment after incubation for 2 days, it was significantly increased in the Fe‐treated plants compared with Fe‐deprived ones after incubation for 4 days. Soil culture experiment showed that the formation of iron plaque on root surfaces was promoted by exogenous iron, with greater amount of iron plaque being formed by addition of ferric hydroxide than of ferric oxide. Phosphorus adsorption on iron plaque also increased with the addition of iron oxides, and increasing soil P increased the amounts of P associated with the iron plaque and shoot P concentration. The amounts of iron plaque were almost sixfold higher under flooding condition than under field capacity condition. Plants pretreated under flooding condition generally had higher shoot P concentrations when they were transplanted to solutions with varying P levels, and this was most pronounced in the treatment with highest solution P concentration. The results suggest that iron plaque acts as a nutrient reservoir for phosphorus in the rhizosphere and helps enhance P acquisition by rice.     

Bayesian image processing of data from constrained source distributions—II. valued,uncorrelated and correlated constraints

Bayesian image processing formalisms which incorporatea priori information about valued-uncorrelated and valued-correlated (patterned) source distributions are introduced and the corresponding iterative algorithms are derived using the EM technique. Striking improvement in image processing is demonstrated when applying these algorithms to Poisson and Gaussian randomized data in one-dimensional cases.     

Cleavage of territrems by alkaline hydrogen peroxide: Isolation and characterization of the aromatic moiety of territrems

The chemical reaction of cleavaging territrem B to give 3,4,5-trimethoxy benzoic acid by alkaline hydrogen peroxide was investigated. The method was applied for confirmation of the chemical structure of the aromatic moiety of territrem A, A’, B, and B’. The physicochemical properties of the aromatic cleavage product of territrem Aindicated the structure as 3,4-methylendioxy, 5-methoxy benzoic acid (or 4-methoxy, 6-carboxy, 1, 3-benzodioxole). The experiment also gave the evidences that territrem A and A’, on the other hand territrem B and B’ have the identical aromatic moieties on their structures.     

Plant regeneration from cultured immature embryos of Sorghum bicolor (L.) Moench

Summary Immature embryos of 20 sorghum genotypes were cultured on MS 5 medium containing MS mineral salts supplemented with 2,4-D, zeatin, glycine, niacinamide, Ca-pantothenate, L-asparagine, and vitamins. For regeneration, calli were transferred onto the same medium with the exception that IAA was substituted for 2,4-D. In general, immature embryos obtained 9–12 days after pollination resulted in the best redifferentiation. Ability of calli to regenerate varied among genotypes; cultivars C401-1 and C625 had the highest redifferentiation frequencies. Ability to redifferentiate was heritable and acted as a dominant trait. At least two gene pairs were involved. Regenerated R₀ plants were planted in a greenhouse and their selfed (R₁ and R₂) progenies were planted in the field and examined for morphological and cytological variations. The majority of the phenotypic variations noted in R₀ were not transmitted to later generations. However, variants for plant height, degree of fertility, and midrib color persisted in R₁ and R₂ generations. A variation in tallness was attributable to one dominant mutant gene. Short stature and male sterility variants appeared to be consequences of recessive mutant genes controlling those traits. Minor variations in peroxidase banding patterns were found among R₀ plants.This study was supported by a research grant from Kansas Sorghum Commission and by a Research Fellowship to the senior author from the Ministry of Agriculture, Animal Husbandry, and Fisheries, China. Contribution 86-456-J from the Kansas Agricultural Experiment Station     

重楼属两种植物种子及其附属结构的发育

重楼属两种植物(五指莲Paris axialis和滇重楼Paris polyphylla var.yunnanensis)种子发育的过程基本一致。双受精发生于授粉后10—15天。胚乳为沼生目型。种子发育延续的时间约为150—170天。胚胎发育终止于球形或稍有分化的阶段。种子具二层种皮。 二种重楼种子成熟时的外部形态显著不同。五指莲Paris axialis的种子呈浅棕黄色,长椭圆形,部分为绿白色海绵质假种皮所包裹。假种皮由珠柄发育而来,呈楔形。滇重楼Parispolyphylla var.yunnanensis的种子鲜红色,不规则圆形,外种皮肉质多浆。无假种皮。珠柄橙黄色,短而纤细。     

Phorbol ester inhibits phosphatidylserine synthesis in human promyelocytic leukaemia HL60 cells. Possible involvement of free radicals and correlation with phosphorylation of nuclear protein 1b.

Treatment of human promyelocytic leukaemia HL60 cells in conditioned medium with 12-O-tetradecanoylphorbol 13-acetate (TPA) for 4 h resulted in 25-30% inhibition of labelling of phosphatidylserine (PS) with [U-14C]serine. PS labelling was 40% lower, and no inhibitory TPA effect was observed when the experiments were performed in fresh medium. Cycloheximide or puromycin also inhibited PS labelling by 38-44%; their inhibitory effects were non-additive with that of TPA and occurred only in conditioned medium. Catalase (CAT) and superoxide dismutase (SOD), both free-radical scavengers, and H7, a protein kinase C inhibitor, reversed to various extents the inhibitory effect of TPA on PS synthesis. On the other hand, chlorobenzoic acid, a free-radical-generating agent, also inhibited PS synthesis by 22% after 4 h treatment when conditioned medium was used. When ethanolamine was added to cells in conditioned medium to quench PS formation through the exchange of free serine with the ethanolamine moiety of phosphatidylethanolamine (PE), PS labelling was decreased by 33% and the inhibitory TPA effect was significantly decreased. On the other hand, ethanolamine had marginal quenching effect on PS labelling when added to cells in fresh medium. TPA increased the phosphorylation of various proteins in the cells, including protein lb (Mr 80,000; pI 5.5) shown to be localized mainly in the nuclear fraction. Chlorobenzoic acid selectively stimulated the phosphorylation of protein lb, whereas CAT and SOD specifically attenuated the TPA-stimulated phosphorylation of this protein. All these agents affected phosphorylation of protein lb only if conditioned medium was used. The findings suggested that net synthesis of PS through the base-exchange mechanism was stimulated in HL60 cells by cell products present in the conditioned medium. TPA inhibited this stimulated PS synthesis by a mechanism which appeared to involve active oxygen species and protein synthesis and might be related to the phosphorylation of protein lb.     

Protein kinase C in fibroblasts. Characteristics of its intracellular location during growth and after exposure to phorbol esters and other mitogens

Using an N-bromosuccinimide cleavage fragment of histone H1 as a relatively specific substrate for protein kinase C, we evaluated the partitioning of this kinase activity between soluble and particulate cellular fractions in 3T3-L1 fibroblasts. In confluent, serum-deprived cells, protein kinase C activity was approximately equally divided between soluble and detergent-extractable particulate fractions; both rapidly growing and transformed cells appeared to contain higher levels of particulate enzyme activity. Soluble protein kinase C activity and immunoreactivity decreased to virtually undetectable levels after exposure of the cells to phorbol 12-myristate 13-acetate (PMA), associated with a commensurate increase in particulate kinase activity and immunoreactivity. In intact cells, PMA appeared to cause a shift of immunoreactive protein kinase C from the cytosol to the perinuclear region, as assessed by immunofluorescent microscopy; however; subcellular fractionation revealed that PMA caused increases in the protein kinase C activity associated primarily with non-nuclear membranes. Exposure of the cells to sn-1,2-dioctanoylglycerol resulted in a modest and transient membrane association of protein kinase C, whereas platelet-derived growth factor, fibroblast growth factor, and bombesin caused no detectable increases in the membrane association of the kinase. Activation of protein kinase C by growth factors in fibroblasts may occur without the gross disturbances in intracellular kinase location which occur in response to phorbol esters.     

Structure function relationships for the IL 2 receptor system. III. Tac protein missing amino acids 102 to 173 (exon 4) is unable to bind IL 2: detection of spliced protein after L cell transfection

High affinity receptors for interleukin 2 (IL 2) contain the Tac protein as one ligand-binding subunit. Localization of the IL 2-binding site on this molecule, as well as localization of the complementary site on IL 2, should provide insight into the design of IL 2 analogs. In this report, we examine the ability of normal and modified Tac protein to bind IL 2 and several antibodies that recognize the native Tac molecule. Using a transient L cell expression system, we have determined that transfection with cDNA-missing Tac exon 4 resulted in expression of spliced protein that had no measurable binding to IL 2 or the monoclonal anti-receptor antibodies, anti-Tac, and 7G7/B6. This protein was detected, however, by rabbit polyclonal antibodies prepared against synthetic Tac peptides. Thus, one or more amino acids encoded by exon 4 is important, either for direct ligand contact or for the proper folding of critical segments of the Tac molecule. In addition, insertion of stop codons at a unique restriction enzyme site near the beginning of exon 5 resulted in cellular secretion of truncated Tac molecules that were capable of binding IL 2, anti-Tac, and 7G7/B6. Amino acids encoded by exons 5 to 8 thus play no critical role in IL 2 binding. The ligand association demonstrated for truncated Tac protein produced by exons 2 to 4 should guide attempts to define the IL 2-binding segment of the Tac molecule.