Acute and/or chronic stress models modulate CuZnSOD and MnSOD protein expression in rat liver

Cellular protection against oxidative stress is afforded by the enzyme superoxide dismutase (SOD). In this study, the protein levels of copper–zinc SOD (CuZnSOD) in the cytosolic and nuclear fraction, manganese SOD (MnSOD) in the mitochondrial, and cytosolic fraction and cytochrome c (cyt c) in the liver of male rats exposed to 2 h of acute immobilization (IM) or Cold stress, 21 days chronic isolation or their combinations (chronic/acute stress) were examined. The serum corticosterone (CORT) level was measured, as an indicator of stress stimuli. Both acute stressors with elevated CORT levels caused a decrease of mitochondrial MnSOD, while acute IM resulted in redistribution of the CuZnSOD protein level between the cytosolic and nuclear fraction. Chronic isolation, during which the CORT level was close to control value, resulted in an increase of cytosolic CuZnSOD, whereas a decrease of MnSOD in mitochondrial and its corresponding increase in cytosol fraction was found. In both combined stress regimes, an increase of the CuZnSOD and MnSOD levels in the cytosolic fraction was recorded whereby increase of the CORT level was observed only in the chronic isolation followed by acute IM. The data indicate that acute and/or chronic stress models have different degrees of influence on serum CORT and SOD subcellular protein levels. Increased cytosolic CuZnSOD protein level under chronic isolation suggests that state of oxidative stress may also exist under CORT level similar to the basal value. The presence of MnSOD and cyt c in the cytosolic fraction could serve as useful parameters for mitochondrial dysfunction.     

Quantitative determination of secoiridoid and xanthone glycosides of Gentiana dinarica Beck cultured in vitro

Gentiana dinarica Beck, native to the Balkan Dinaric Mountains, was established in vitro from axillary shoot buds. It was maintained in the form of shoot cultures on MS medium supplemented with 1.0 mg l^?1 6-benzyladenine (BA) and 0.1 mg l^?1 α-naphthaleneacetic acid and excised root cultures were maintained on ½ MS medium with 0.5 mg l^?1 indole-3-butyric acid (IBA). Shoot cultures, adventitious roots and excised root cultures were analysed by HPLC techniques for the presence of secoiridoids and xanthones. Gentiopicrin and swertiamarin, the dominant components of shoot cultures, could not be detected in root cultures. Xanthones were present in both shoot and root cultures with norswertianin-1-O-primeveroside as the dominant metabolite. The secoiridoid and xanthone content, although characteristic for certain plant organs, was dependent on the concentration of plant growth regulators (BA and IBA) added to the medium. BA in the shoot multiplication stage strongly increased the secondary metabolite (SEM) content of shoot cultures. IBA had little effect on SEM accumulation in shoots during rooting, while it moderately stimulated SEM accumulation in excised root cultures.     

Alien invasive neophytes of the Southeastern part of the Pannonian Plain

Floristic diversity in the Pannonian Plain is the result of mosaic habitat composition, characterized by steppes, saline meadows, and lowland forests along major rivers. In the last few centuries, the flora has become enriched by species introduced by human activities, such as colonization and industrialization. Presently it consists of nearly 1800 species. As a result of 30 years of field research as well as herbarium and literature searches, a list of invasive alien neophytes has been compiled and is presented here. The list includes 152 species, classified as either naturalized, casual, or unknown. One of the species is listed in Red Book of Serbian Flora. Eighty species are naturalized, and 61 are casual species. The majority of the introduced flora originates from North America (66) and the Old World (43). Most alien invasive species of the Southeastern part of the Pannonian Plain, were introduced accidentally by seed material or deliberately by nursery saplings. The annual and perennial herbaceous plants, which flower in the summer and summer-autumn periods, are represented in the greatest numbers. The alien flora was further analyzed with respect to taxonomy, life forms, pollination, and seed dispersal mode. The greatest number of alien species appears in anthropogenic and semi-natural habitats (59). In natural habitats, 45 invasive taxa were recorded, representing a conservation threat to biodiversity.     

Effects of Acute In vivo Cisplatin and Selenium Treatment on Hematological and Oxidative Stress Parameters in Red Blood Cells of Rats

Although cisplatin (cisPt) is one of the most often used cytotoxic drugs in the treatment of cancer, its clinical application is associated with nephrotoxicity and a cumulative anemia. In this study, we evaluated posible protective effects of selenium (Se) on hematological and oxidative stress parameters in rats, acutely treated with cisPt. Four groups of Wistar albino rats included control rats, cisPt-treated (7.5 mg/kg of body weight of cisPt, i.p.), Se-treated (6 mg/kg of body weight of Na₂SeO₄, i.p.), and Se and cisPt co-treated rats. The rats were killed 72 h after treatment; hematological and oxidative stress parameters were followed in red blood cells. The results showed depletion in platelet number induced by high acute doses of cisPt and strong utilization of reduced glutathione, resulting in elevation of GSSG/2 GSH ratio. Se treatment was followed by stimulated erythropoiesis, increased lipid peroxidation, and GSH depletion. Se and cisPt co-treatment were followed by stimulated erythropoiesis and significant recovery of reduced glutathione status when compared with cisPt-treated rats. In conclusion, acute doses of Se and cisPt primarily act as pro-oxidants. CisPt influenced antioxidative properties of exogenous Se and their synergistic effects may partially participate in protection against cisPt-induced toxicity.     

An allelopathic investigation of the domination of the introduced invasive Conyza canadensis L.

The introduced, invasive species Conyza canadensis L. covers large areas of the sandy levees next to the River Tamiš (Serbia), forming dense microcomplexes and dominating the other herbaceous species in the ruderal phytocoenosis with its aboveground mass and abundance. In addition to this species, a further 28 plant species were found, but the abundance and cover of these was significantly lower. The allelopathic influence of the species C. canadensis was investigated through analyzing the total phenolics and phenolic acids, as the main allelochemicals, in dead and vegetative parts and the soil beneath them. Seed germination and seedling growth of the target plants (Dactylis glomerata L. and Trifolium repens L.), which grow in this community, served as a measure of the inhibitory capacity of this species. It was established that the content of total phenolics and phenolic acids (p-coumaric, ferulic, p-hydroxybenzoic, vanillic and syringic) varies, following the order: vegetative plant parts > dead plant parts > sandy soil under C. canadensis. Water leachate and soils inhibited seed germination and seedling growth of the test plants to varying degrees, following the order: vegetative parts > dead parts > sandy soil, which is directly related to the content of total phenolics and phenolic acids in them. It was concluded that the pioneer species C. canadensis plays a decisive role in the first phases of vegetation succession and the process of soil formation on the barren sandy levees, owing to the synthesis of secondary phenolic metabolites.     

Model of the assessment of the critical risk of extinction and the priorities of protection of endangered aquatic species at the national level

In the period 1995–2006, the biodiversity of the aquatic habitats in the area of Serbia was explored, with the aim to identify the endangered species of macroalgae, macroinvertebratae and fishes. During the work a data base was formed (Aquatic Ecosystems Diversity in Serbia, AEDSer), containing the data from exploring the biodiversity of the aquatic ecosystems of Serbia since 1860. Based on the data base, classification of the aquatic species was made into categories of endangerment based on IUCN criteria. The following was noted: (1) the global IUCN category assigned to the species often is not identical with the national status of endangerment; and (2) the species that are given a category of endangerment at the national level do not have the same realistic risk of extinction in all their habitats. This remark imposed the need for a model for assessing the critical risk of extinction of the endangered species and determining the priorities of their protection at the national level. Two categories of characters were used to develop the model: the characters that determine the degree of ecological specialisation of the species based on the circumstances of habitat; and the characters suggesting the risk factors from the system: “HIPPO” in the spatial and time dimension. The possibility to apply the model was tested on 10 aquatic species belonging to different categories of endangerment at the national level (macroalgae 2, macroinvertebrates 7, and fishes 1 species). The model based on points determined the level of extinction risk and, that way, the species needing urgent conservation from the same or different categories of endangerment were isolated. The model suggested can contribute to a more efficient defining the conservation priorities.     

Somatic embryogenesis and shoot organogenesis from the hypocotyl slices and free radical scavenging activity of regenerants of collard greens (Brassica oleracea L. var. acephala)

Brassica oleracea var. acephala is an important leafy vegetable that has been widely consumed as a high-nutrient, low-calorie food. Because of the plant’s biennial and self-incompatibility nature, biotechnological approaches are alternative way for propagation and breeding improvements. Since tissue culture studies have been focused in other B. oleracea representatives, the aim of the present study was to achieve effective regeneration protocol distinctive for collard greens, and evaluate the total phenolic content and antioxidant activity of regenerants. The effect of 3 cytokinins [thidiazuron (TDZ), 6-benzyladenine (BA) and 6-furfuryladenine (kinetin, KIN)] at increasing concentrations (0, 5, 7.5, 10, 20 or 30 µM) in combination with tenfold lower concentration of 1-naphtaleneacetic acid (NAA) (0, 0.5, 0.75, 1, 2 or 3 µM, respectively) on the regeneration from hypocotyl slices was studied. Histological analysis revealed the two regeneration pathways, somatic embryogenesis and shoot organogenesis, simultaneously occurred in the same explant, regardless of the cytokinin/NAA combinations used. The regeneration frequency of 95.9%, with 7.5 morphogenic structures regenerated per explant, and the healthy appearance of regenerated plants indicated the optimal combination 20 µM TDZ?+?2 µM NAA. TDZ at 5 µM provided the high somatic embryo proliferation rate by generation of secondary embryos (7.79) along with the lowest rate of their abnormalities. Embryo-developed plants were successfully acclimatised (above 90%). The plants regenerated and proliferated on TDZ-containing media had higher total phenolic content that correlated with the highest free radical scavenging activity (IC₅₀?=?19.09 µg ml^??1).

     

Galectin-1 binds mucin in human trophoblast

Mucins are multifunctional highly glycosylated proteins expressed by the female reproductive tract. Differential expression of MUC1 and MUC15 has been shown in trophoblast. This study was undertaken to establish the distribution of mucin(s) in cytotrophoblast cell cultures using anti-bovine submaxillary mucin (BSM) and to investigate the possibility of MUC1/mucin(s) being a binding partner of trophoblast galectin-1. MUC1 is demonstrated here using immunocytochemistry on isolated cytotrophoblast and the HTR-8/SVneo extravillous trophoblast cell line but detection of additional trophoblast mucins cannot be excluded. Western blot analysis showed similar bands ranging from 30 to >200 kDa with anti-BSM and the well-known mucin antibodies HMFG1 and B72.3. Immunocytochemistry and cell-based ELISA data were found to support that all of the antibodies used are reactive with BSM, suggesting the presence of shared epitopes between BSM and trophoblast mucin(s). Binding of galectin-1 to trophoblast MUC1/mucin(s) was analyzed using a solid-phase assay and co-immunoprecipitation. Recombinant galectin-1 binding to isolated trophoblast mucin in solid-phase assay was sensitive to lactose, a carbohydrate inhibitor of galectin binding. In whole HTR-8/SVneo lysates, ~200 kDa mucin was detected in galectin-1 immunoprecipitates, while endogenous galectin-1 was present in BSM-immunoprecipitates. Furthermore, double fluorescence immunocytochemistry showed overlap of galectin-1 and trophoblast mucins at the plasma membrane of HTR-8/SVneo cells. These results suggest that trophoblast mucin(s) could act as binding partners of galectin-1, in a carbohydrate-dependent manner.