Antioxidant activity of fluoxetine: Studies in mice melanoma model

In vivo effects of the antidepressant fluoxetine on spleen antioxidant status of C57BL/6 mice were studied using a melanoma experimental model. After a 14‐day treatment with fluoxetine (10 mg kg^?1 day^?1, i.p.), the endogenous antioxidant non‐enzyme (glutathione) and enzyme (superoxide dismutase (SOD) and glutathione peroxidase (GPx)) defense systems in spleen of healthy animals were not changed; the lipid peroxidation (LP) was also unchanged. When B16F10 melanoma cells were introduced in C57BL/6 mice 2 h before fluoxetine treatment, a drug‐protective effect against the melanoma‐induced oxidative changes (increased LP and decreased total glutathione (GSH)‐level, as well as antioxidant enzyme activities) in spleen was observed. Fluoxetine dose‐dependently reduced the amounts of free oxygen radicals (hydroxyl and superoxide anion radicals), generated in chemical systems. Taken together, the present results suggest that fluoxetine, acting as antioxidant, prevents from melanoma‐induced oxidative changes in mice spleen. Copyright © 2010 John Wiley & Sons, Ltd.     

Acceptability of different species of Brassicaceae as hosts for the cabbage aphid

The probing and feeding behaviour of the cabbage aphid, Brevicoryne brassicae (L.), (Homoptera, Aphididae) was studied on several plant species that represented various levels of acceptability: Sinapis alba L. (a permanent host plant), Capsella bursa-pastoris (L.) Med., Thlaspi arvense L., Lunaria annua L., Erysimum cheiranthoides L. (accidental host plants), Vicia faba L. (a non-host plant), using the electrical penetration graph technique (EPG). B. brassicae on V. faba did not show any patterns related to penetration of phloem vessels. Stylet penetration was deterred on L. annua and E. cheiranthoides where non-penetration prevailed, the periods of sap ingestion were short or did not occur, the percentage of time spent in the phloem was consistently low (5–6%) and E1 salivation predominated. The pathway activities were not suppressed on C. bursa-pastoris and T. arvense and the aphids spent an average of 3 h in the phloem during the 8-h experiment. However, a considerable delay between finding and accepting the phloem and a substantial proportion of E1 salivation (20–30% of all phloem activities) indicated a deterrent factor in the sieve elements of these plants. Aphid probing and sap ingestion were rarely interrupted on S. alba. The results of this study suggest that the deterrent agents vary in activity and may hinder stylet penetration at different levels (epidermis, parenchymatous tissues and/or phloem elements), depending on the plant species.     

Haptoglobin glycoforms in a case of carbohydrate-deficient glycoprotein syndrome

Alterations in haptoglobin (Hp) glycosylation were examined in the plasma of the first patient with carbohydrate-deficient glycoprotein syndrome (CDGS) who was described in Poland. Hp concentration in the CDGS patient plasma was low (240mg/l) and the Hp phenotype was shown to be 2-2. Three glycoforms of the Hp subunit were observed in SDS-PAGE in CDGS. The densitometric analysis and molecular weight determinations suggested that 50% of glycoforms were fully glycosylated; 30% contained three out of four and 20% only two out of four glycan units compared to those that are present in Hp derived from healthy people. Results with lectins (concanavalin A and Sambucus nigra, Maackia amurensis and Alleuria aurantia agglutinins) indicate that all three glycoforms of subunit of CDGS-Hp contained biantennary complex glycans terminated with 2,6 bound sialic acid, but without fucose or 2,3 linked sialic acid. Hp glycosylation abnormalities described in this work suggest that this case was a type I carbohydrate-deficient glycoprotein syndrome.     

Malate accumulation in different organs of Mesembryanthemum crystallinum L. following age-dependent or salinity-triggered CAM metabolism

Different organs of Mesembryanthemum crystallinum exhibit differing levels of CAM (Crassulacean acid metabolism), identifiable by quantification of nocturnal malate accumulation. Shoots and also basal parts of young leaves were observed to accumulate high concentrations of malate. It was typically found in mature leaves and especially prominent in plants subjected to salt stress. Small amount of nocturnal malate accumulation was found in roots of M. crystallinum plants following age-dependent or salinity-triggered CAM. This is an indication that malate can be also stored in non-photosynthetic tissue. Measurements of catalase activity did not produce evidence of the correlation between activity of this enzyme and the level of malate accumulation in different organs of M. crystallinum although catalase activity also appeared to be dependent on the photoperiod. In all material collected at dusk catalase activity was greater than it was observed in the organs harvested at dawn.     

Engineering of an artificial glycosylation pathway blocked in core oligosaccharide assembly in the yeast Pichia pastoris: production of complex humanized glycoproteins with terminal galactose

A significant percentage of eukaryotic proteins contain posttranslationalmodifications, including glycosylation, which are required forbiological function. However, the understanding of the structure–functionrelationships of N-glycans has lagged significantly due to themicroheterogeneity of glycosylation in mammalian produced proteins.Recently we reported on the cellular engineering of yeast toreplicate human N-glycosylation for the production of glycoproteins.Here we report the engineering of an artificial glycosylationpathway in Pichia pastoris blocked in dolichol oligosaccharideassembly. The PpALG3 gene encoding Dol-P-Man:Man₅GlcNAc₂-PP-Dolmannosyltransferase was deleted in a strain that was previouslyengineered to produce hybrid GlcNAcMan₅GlcNAc₂ human N-glycans.Employing this approach, combined with the use of combinatorialgenetic libraries, we engineered P. pastoris strains that synthesizecomplex GlcNAc₂Man₃GlcNAc₂ N-glycans with striking homogeneity.Furthermore, through expression of a Golgi-localized fusionprotein comprising UDP-glucose 4-epimerase and ß-1,4-galactosyltransferase activities we demonstrate that this structure isa substrate for highly efficient in vivo galactose addition.Taken together, these data demonstrate that the artificial invivo glycoengineering of yeast represents a major advance inthe production of glycoproteins and will emerge as a practicaltool to systematically elucidate the structure–functionrelationship of N-glycans. ¹ These authors contributed equally to this work. ² To whom correspondence should be addressed; e-mail: swildt{at}glycofi.com     

Protective role of 20-hydroxyecdysone against lead stress in Chlorella vulgaris cultures

Treatment of cultured C. vulgaris cells with 10(-6)-10(-4) M lead decreased their growth and chemical composition during the first 48 h of cultivation. However, at concentrations above 10(-4) M, lead is cytotoxic to Chlorella vulgaris cells, resulting in cellular fragmentation and lysis. In contrast, at concentrations below 10(-6) M lead had no influence on the growth and metabolism of C. vulgaris cells. 20-Hydroxyecdysone (20E) (10(-10)-10(-8) M) increased growth and chemical composition of C. vulgaris cells over a concentration range. Levels per cell of chlorophylls, protein, sugars are all increased by 20E treatment, when compared to non-treated control cells. However, the cultures treated with 20E and lead show a lower stimulation than the cultures treated with 20E alone. The effects of 20E mixed with lead on the growth and the level of cellular lead, chlorophyll, sugar and protein in C. vulgaris are also reported. The decreased growth and composition of C. vulgaris cells treated with lead was restored by the 20E. Application of 20E to C. vulgaris cultures reduced the impact of lead stress on growth, prevented chlorophyll, sugar and protein loss and increased phytochelatins synthesis. Furthermore, 20E did not restore toxic effect of lead on C. vulgaris cells. The combined treatment with lead and 20E appeared to have a stimulatory effect on the above parameters during the 48 h of cultivation, as compared to the control. 20E reduced the toxicity of lead and the growth recovered to the level of cells treated with 20E alone. Concentration-dependent stimulation was observed with increasing concentration of 20E and decreasing concentration of lead.     

Nitric oxide complexes in the interaction between primary and secondary tumor of L5178Y lymphoma.

Heme and non-heme Fe-NO complexes were observed in regard to the growth of primary and secondary solid tumors and ascites of murine L5178Y lymphoma. The complexes were detected by electron paramagnetic resonance spectroscopy at liquid nitrogen temperature. Primary solid tumors and secondary solid tumors or ascites were inoculated on the same day, or with a delay. The primary tumor inhibited growth of the secondary solid tumor only if the latter was inoculated with a delay, which did not correlate with the change of the types, nor with the increase in the level of Fe-NO complexes detected in the tissue, suggesting a "non-immunological" character of this inhibition. In some animals with solid tumors, spontaneous ascites developed. This process resulted in a marked decrease in the level of Fe-NO complexes in the solid tumor tissue. The primary solid tumor, however, did not influence the growth of secondary ascites, but intensified NO generation in the ascites of animals with partial removal of ascitic fluid. This experimental group survived 2.2 days longer than the control group without primary solid tumor. Our research revealed that the presence of Fe-NO complexes in the interaction between primary and secondary tumor strongly depends on the form of the tumor: solid or ascitic, and that murine L5178Y lymphoma may serve as a convenient model for the research on "concomitant immunity" against in vivo growing tumors. This is the first EPR study on "concomitant immunity" in regard to tumor-tumor and tumor-ascites interactions in vivo.     

Characteristics of arylsulfatase in Russian sturgeon (Acipenser gueldenstaedti) semen

Spermatozoa of sturgeons (Acipenseriformes), unlike teleosts, possess an acrosome. This paper provides data concerning biochemical characteristics of arylsulfatase (AS), an acrosomal enzyme, found in Russian sturgeon spermatozoa and seminal plasma. The enzymes were purified by a four-step procedure, using n-butanol extraction, ion-exchange chromatography repeated twice and gel filtration. High purity of our enzymes was confirmed by silver staining electrophoresis and an immunological experiment. Kinetic parameters indicated that the purified enzymes belong to arylsulfatase type A. Similarity of the seminal plasma arylsulfatase to the spermatozoan enzyme showed us that arylsulfatase from seminal plasma might originate from damaged spermatozoa. The possible physiological consequences of the presence of arylsulfatase in Russian sturgeon semen are discussed.