Indoxyl sulfate induces apoptosis in mononuclear blood cells via mitochondrial pathway

The consequence of chronic kidney disease is the accumulation of metabolic products called uremic toxins in the body. Indoxyl sulfate (IS) is a toxin with a high affinity for proteins. This study focuses on the deleterious effect of IS, especially apoptosis induction, in mononuclear blood cells (MNCs). Thus, in MNCs treated with IS at three different concentrations for 24 h, the survival, mitochondrial potential, caspases activity and expression, Bcl-2 and Bax protein expression, DNA damage, and PARP degradation were estimated. The study showed a decrease in survival and mitochondrial potential of MNCs treated with IS compared to the control. IS increased the activity of caspase 2-, 3-, 9-, and the expression of caspase 3-, and 9- in MNCs but does not affect the activity of caspase 6- and 8. The treatment of MNCs with IS also increased DNA damage and degradation of PARP. Indoxyl sulfate significantly influences the expression of Bcl-2 and Bax proteins. Indoxyl sulfate induces the programmed death of MNCs through the intrinsic mitochondrial apoptotic pathway. The observed cellular changes are mostly dose-dependent

Immunolocalization of dually phosphorylated MAPKs in dividing root meristem cells of Vicia faba, Pisum sativum, Lupinus luteus and Lycopersicon esculentum

Key message In plants, phosphorylated MAPKs display constitutive nuclear localization; however, not all studied plant species show co-localization of activated MAPKs to mitotic microtubules. Abstract The mitogen-activated protein kinase (MAPK) signaling pathway is involved not only in the cellular response to biotic and abiotic stress but also in the regulation of cell cycle and plant development. The role of MAPKs in the formation of a mitotic spindle has been widely studied and the MAPK signaling pathway was found to be indispensable for the unperturbed course of cell division. Here we show cellular localization of activated MAPKs (dually phosphorylated at their TXY motifs) in both interphase and mitotic root meristem cells of Lupinus luteus, Pisum sativum, Vicia faba (Fabaceae) and Lycopersicon esculentum (Solanaceae). Nuclear localization of activated MAPKs has been found in all species. Colocalization of these kinases to mitotic microtubules was most evident in L. esculentum, while only about 50 % of mitotic cells in the root meristems of P. sativum and V. faba displayed activated MAPKs localized to microtubules during mitosis. Unexpectedly, no evident immunofluorescence signals at spindle microtubules and phragmoplast were noted in L. luteus. Considering immunocytochemical analyses and studies on the impact of FR180204 (an inhibitor of animal ERK1/2) on mitotic cells, we hypothesize that MAPKs may not play prominent role in the regulation of microtubule dynamics in all plant species

Diosmin and Bromelain Stimulate Glutathione and Total ThiolsProduction in Red Blood Cells

Diosmin and bromelain are bioactive compounds of plant origin with proven beneficialeffects on the human cardiovascular system. We found that diosmin and bromelain slightly reducedtotal carbonyls levels and had no effect on TBARS levels, as well as slightly increased the totalnon-enzymatic antioxidant capacity in the RBCs at concentrations of 30 and 60μg/mL. Diosminand bromelain induced a significant increase in total thiols and glutathione in the RBCs. Examiningthe rheological properties of RBCs, we found that both compounds slightly reduce the internalviscosity of the RBCs. Using the MSL (maleimide spin label), we revealed that higher concentrationsof bromelain led to a significant decrease in the mobility of this spin label attached to cytosolic thiolsin the RBCs, as well as attached to hemoglobin at a higher concentration of diosmin, and for bothconcentrations of bromelain. Both compounds tended to decrease the cell membrane fluidity inthe subsurface area, but not in the deeper regions. An increase in the glutathione concentrationand the total level of thiol compounds promotes the protection of the RBCs against oxidative stress,suggesting that both compounds have a stabilizing effect on the cell membrane and improve therheological properties of the RBCs

Microcystin assimilation and detoxification by Daphnia spp. in two ecosystems of different cyanotoxin concentrations

Microcystins (MCs), the main group of cyanotoxins, can induce oxidative stress in the cells of aquatic animals. This study evaluated the sensitivity of daphniids – from two ecosystems characterised by different trophic states and habitat levels of cyanobacteria abundance – to microcystin toxicity by analysing oxidative stress parameters and MC detoxification ability. As a study site, we chose the eutrophic Sulejow reservoir, which has regular annual toxic cyanobacterial blooms, and the mesotrophic lake Białe, where low abundances of cyanobacteria have only recently appeared. We found much higher accumulations of MCs in tissues of Daphnia spp. in lake Białe, despite low toxin concentrations in this ecosystem compared with the Sulejow reservoir. Simultaneously, high levels of lipid peroxidation (LPO) and a significant decrease in glutathione (GSH) were observed in daphniid cells in lake Białe, while LPO levels were generally lower and GSH concentration more stable in the Sulejow reservoir. Catalase activity, which reflects more efficient oxidative protection, was always significantly higher in the reservoir than in lake Białe. These results demonstrate that generations of daphniids from the Sulejow reservoir had more effective antioxidant systems protecting them against the accumulation of cyanobacterial toxins; thereby, they are less susceptible to toxic effects than the daphniids from lake Białe. However, the presence of conjugate forms of microcystins (MC-GSH and MC-Cys) in tissues of the studied animals indicated the ability for MC detoxification by daphniids from the Sulejow reservoir and lake Białe. Nevertheless, the high effectiveness of antioxidant systems in daphniids coexisting with cyanobacteria for a long time in the Sulejow reservoir indicates the importance of a selective pressure exerted by toxic cyanobacterial strains that favours the most resistant daphniid genotypes

Response of <i>Daphnia</i>'<i>s</i> Antioxidant System to Spatial Heterogeneity in Cyanobacteria Concentrations in a Lowland Reservoir

<div><p>Many species and clones of <i>Daphnia</i> inhabit ecosystems with permanent algal blooms, and they can develop tolerance to cyanobacterial toxins. In the current study, we examined the spatial differences in the response of <i>Daphnia longispina</i> to the toxic <i>Microcystis aeruginosa</i> in a lowland eutrophic dam reservoir between June (before blooms) and September (during blooms). The reservoir showed a distinct spatial pattern in cyanobacteria abundance resulting from the wind direction: the station closest to the dam was characterised by persistently high <i>Microcystis</i> biomass, whereas the upstream stations had a significantly lower biomass of <i>Microcystis</i>. Microcystin concentrations were closely correlated with the cyanobacteria abundance (r = 0.93). The density of daphniids did not differ among the stations. The main objective of this study was to investigate how the distribution of toxic <i>Microcystis</i> blooms affects the antioxidant system of <i>Daphnia</i>. We examined catalase (CAT) activity, the level of the low molecular weight antioxidant glutathione (GSH), glutathione S-transferase (GST) activity and oxidative stress parameters, such as lipid peroxidation (LPO). We found that the higher the abundance (and toxicity) of the cyanobacteria, the lower the values of the antioxidant parameters. The CAT activity and LPO level were always significantly lower at the station with the highest <i>M. aeruginosa</i> biomass, which indicated the low oxidative stress of <i>D. longispina</i> at the site with the potentially high toxic thread. However, the low concentration of GSH and the highest activity of GST indicated the occurrence of detoxification processes at this site. These results demonstrate that daphniids that have coexisted with a high biomass of toxic cyanobacteria have effective mechanisms that protect them against the toxic effects of microcystins. We also conclude that <i>Daphnia</i>'s resistance capacity to <i>Microcystis</i> toxins may differ within an ecosystem, depending on the bloom's spatial distribution.</p></div

Study site.

<p>Map of the Sulejow Reservoir with sampling sites.</p

Density of <i>Daphnia longispina</i> in the sites of the Sulejow Reservoir.

<p>Density of <i>Daphnia longispina</i> [ind dm⁻³] in the three studied sites: Tresta (TR), Bronisławów (BR) and Zarzęcin (ZA). The sampling was conducted monthly between June and September of 2012, and on September of 2014.</p><p>Density of <i>Daphnia longispina</i> in the sites of the Sulejow Reservoir.</p

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The cyanobacteria abundance and activity of the antioxidant parameters in <i>Daphnia</i> tissues, measured in August 2012.

<p>(A) The bars represent an average of three replicates (±S.D.) of cyanobacteria abundance (µg dm⁻³); the dark dots indicate the total concentration of microcystins LR and RR (µg g⁻¹), (B) The bars represent an average of seven replicates (±S.D.) of glutathione (GSH) concentrations (nmol/mg protein), (C) The bars represent an average of seven replicates (±S.D.) of lipid peroxidation (LPO) (nmol/mg protein) and (D) The bars represent an average of six replicates (±S.D.) of catalase (CAT) activity (U/mg protein) in <i>Daphnia</i> tissues from the Sulejow Reservoir in 2012. The same letters above the bars indicate that the values did not differ significantly. Each panel of the figure includes the one-way ANOVA test results. Details concerning GSH, LPO and CAT data are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112597#pone.0112597.s001" target="_blank">Tables S1</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112597#pone.0112597.s002" target="_blank">S2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112597#pone.0112597.s003" target="_blank">S3</a>.</p