Cloning and functional characterization of a GNA-like lectin from Chinese Narcissus (Narcissus tazetta var. Chinensis Roem).

A full-length cDNA encoding Narcissus tazetta lectin (NTL) was isolated from Chinese narcissus (N. tazetta var. Chinensis Roem). The open reading frame (ORF) was 519 bp long and encoded 172 amino acids with a theoretical isoelectric point of 5.27 and a calculated molecular mass of 18.6 kDa. Conserved domain analysis indicated that it possessed three D-(+)-mannose-binding sites, presumed to be similar to those of Galanthus nivalis agglutinin (GNA)-like lectins. A recombinant (glutathione S-transferase) GST-NTL fusion protein of around 40 kDa was successfully synthesized in vitro. Lysates of cells expressing this recombinant protein exhibited significant hemagglutinating activity [418 hemagglutinating units (HU)], as did the purified protein (265 HU). Sugar specificity assays suggested that mannose is the only sugar that significantly inhibits this hemagglutinating activity, confirming that NTL is a member of the GNA-like lectin family. NTL is highly transcribed in flowers, leaves and roots, but less so in scales. However, similar levels of the NTL protein were observed in all four of these organs by western blotting. A fluorescent NTL-GFP (green fluorescent protein) fusion protein was found to be primarily localized in the vacuole of transformed onion epidermal cells, indicating that NTL may be a vacuolar storage protein. This is the first study in which the function of NTL has been examined and provides a considerable body of data concerning its physiological role in Chinese narcissus. The results obtained may be useful in the molecular engineering of plants with enhanced tolerance of biotic and abiotic stresses. Moreover, they may be relevant to medical applications of lectins.

Identification of differentially expressed genes in early stages of Eimeria tenella by suppression subtractive hybridization and cDNA microarray.

Avian coccidiosis, a major parasitic disease of poultry, is caused by Eimeria spp. infection. It inflicts severe economic losses on the poultry industry worldwide. To further understand the molecular basis of sporulation and invasion of Eimeria spp., suppression subtractive hybridization and microarray approaches were combined to identify novel and important genes involved in the development and invasion of the early stages of Eimeria tenella . Three subtractive cDNA libraries were constructed for 3 stages of E. tenella including unsporulated oocysts, sporulated oocysts, and sporozoites. A subset of clones was selected from the 3 subtractive libraries to construct cDNA microarrays. Microarray analysis was used to assay expression changes of these clones. A total of 657 valid expressed sequence tags (ESTs) was obtained, including 119 unique sequences, 31 from sporulated oocysts and 88 from sporozoites. Homology searches of the public sequence databases showed that, among the 119 ESTs, 32 genes encoded proteins homologous with previously reported proteins including microneme proteins and surface antigen proteins of E. tenella , small heat shock proteins, rhoptry proteins of Toxoplasma gondii , and calcium-dependent protein kinase of Plasmodium spp. Thus, the remaining 87 ESTs have not previously been reported. Further characterization of these differentially expressed genes will be useful in understanding those responsible for sporulation, invasion, growth, and development of E. tenella .

Performance of an intensive pond system treating municipal wastewater in a cold region.

A full-scale intensive pond system (IPS) with shorter HRT was designed, constructed and operated in Jining, Inner-Mongolia for the treatment of municipal wastewater, which is a mixed domestic and industrial wastewater characterized by quite high SS and lower BOD5/COD ratio values or lower biodegradability. Therefore, the pond system was designed as an integrated intensive pond system (IIPS) consisting of settling/anaerobic pond (SAP), intensified anaerobic pond (IAP), facultative pond (FP), and polishing ponds (PPs). In order to improve the performance of the IPS, some intensified measures were made, including inlet and outlet even-distribution systems of each unit pond, package of biofilm carrier in IAP for the increase and even distribution of biomass; overflow waterfalls on the dikes between unit ponds for the increase of DO in pond water, gravel filtration dike (or dam) for removing suspended solids including algae, which have improved the performance of the IPS remarkably in terms of removal of main pollutants, such as SS, COD, BOD5, TN, NH3-N, TP and total bacteria. The final effluent from the IPS in warm seasons from May to October were SS 7.2-10.8 mg/L, BOD5 8.5-19.6 mg/L, COD 44.1 - 76.5 mg/L, and NH3-N 1.5-10.2 mg/L, which well meet Chinese national discharge standard (2nd class) of secondary municipal wastewater treatment plants, i.e. BOD5 and SS 30 mg/L respectively, COD 100 mg/L, and NH3-N 25 mg/L.

Preparation and biological evaluation of radiolabelled antibodies with selected carbohydrate modifications.

Two carbohydrates, N-acetylgalactosamine (GalNAc) and galactose-beta-1,3-GalNAc have been attached to human IgG (hIgG) by a novel linking reagent, hexafluoroglutaric acid dimethyl ester. Fluorine-19 NMR signals were used for the determination of the conjugation ratio. A third carbohydrate, sialic acid, was conjugated via reductive amination and the conjugation ratio determined by a resorcinol assay. The biological behaviour of these radioiodinated antibodies with carbohydrate modifications in normal mice indicates an enhanced liver uptake at 15 min post-injection with an associated change in circulating blood levels occurs for the galactose-based hIgG preparations. However, no significant differences in the biodistribution were observed for the sialic acid conjugate. These studies confirm the potential of carbohydrate-antibody conjugation for modifying the behaviour of antibodies in immunoscintigraphy and radioimmunotherapy.

[Studies on the antiarrhythmic effects of leaves of Dendropanax chevalieri (Vig.) Merr. et Chun].

Aqueous extract of the leaves of Dendropanax chevalieri (DC), administrated orally, showed prominent protective effect against arrhythmias induced by iv aconitine CaCl2 (120mg/kg) in mice and BaCl2 (4mg/kg) in rats. In anesthetized rabbits, the duration of arrhythmia elicited by ivAdr 75 micrograms/kg was markedly shortened by iv DC 0.4g/kg. It might also obviously delay the onset of arrhythmias and cardiac electricity disappearance evoked by ouabain perfusing consistently into isolated guinea-pig hearts.