The protective effect of selenium inorganic forms against cadmium and silver toxicity in mycelia of Pleurotus ostreatus

The effect of two inorganic selenium forms has been investigated in the mycelia of Pleurotus ostreatus exposed to cadmium and silver salts in the shaken cultures. The degree of toxicity was assessed by the determination of malondialdehyde (MDA; a common biomarker of lipid peroxidation). The mycelia were exposed to one element form (up to 5 mg l⁻¹) and also to the following combinations: cadmium(II) + selenium(IV); cadmium(II) + selenium(VI); silver(I) + selenium(IV); silver(I) + selenium(VI). The concentrations of cadmium, silver, selenium, and MDA were assessed in the mixed cytosol and cell membrane fractions (CCM). A positive correlation between MDA and cadmium was found in the CCM (β = 0.7775, P = 0.0001), whereas the effect of silver was less significant (β = 0.4642, P = 0.039). These results indicate that silver(I) and cadmium(II) have different capacities to induce lipid peroxidation in P. ostreatus. The protective role of selenium against metal-induced oxidative damage was found to be dependent on the oxidation state of the element form in the growth medium. The strongest beneficial effect was observed in mycelia exposed to cadmium(II) + selenium(IV) (inverse correlation between MDA and selenium in the CCM: β = −0.7129, P = 0.009) and it has been ascribed to a lower incorporation of the toxic metal and/or to possible intracellular interaction between selenium and cadmium. Under exposure to silver(I), the protective effect of selenium(IV) was less noticeable (correlation between MDA and selenium in the CCM; β = −0.6068, P = 0.036); in the presence of selenium(VI), no beneficial effect was observed.     

TMEFF2 shedding is regulated by oxidative stress and mediated by ADAMs and transmembrane serine proteases implicated in prostate cancer

TMEFF2 is a type I transmembrane protein with two follistatin (FS) and one EGF‐like domain over‐expressed in prostate cancer; however its biological role in prostate cancer development and progression remains unclear, which may, at least in part, be explained by its proteolytic processing. The extracellular part of TMEFF2 (TMEFF2‐ECD) is cleaved by ADAM17 and the membrane‐retained fragment is further processed by the gamma‐secretase complex. TMEFF2 shedding is increased with cell crowding, a condition associated with the tumour microenvironment, which was mediated by oxidative stress signalling, requiring jun‐kinase (JNK) activation. Moreover, we have identified that TMEFF2 is also a novel substrate for other proteases implicated in prostate cancer, including two ADAMs (ADAM9 and ADAM12) and the type II transmembrane serine proteinases (TTSPs) matriptase‐1 and hepsin. Whereas cleavage by ADAM9 and ADAM12 generates previously identified TMEFF2‐ECD, proteolytic processing by matriptase‐1 and hepsin produced TMEFF2 fragments, composed of TMEFF2‐ECD or FS and/or EGF‐like domains as well as novel membrane retained fragments. Differential TMEFF2 processing from a single transmembrane protein may be a general mechanism to modulate transmembrane protein levels and domains, dependent on the repertoire of ADAMs or TTSPs expressed by the target cell.     

Using biosorption to enrich the biomass of <Emphasis Type="Italic">Chlorella vulgaris </Emphasis>with microelements to be used as mineral feed supplement

The paper discusses biosorption of Cr(III), Cu(II), Mn(II), Zn(II) and Co(II) to the biomass of Chlorella vulgaris, to produce a biologically bound, concentrated form of microelements. The kinetics of biosorption was described with a pseudo-second order equation and equilibrium with the Langmuir isotherm. The mechanism of biosorption was identified as cation-exchange with alkaline metals. Cation-exchange capacity was evaluated as 4.07 meq g⁻¹. The effect of operation conditions, pH and temperature, on biosorption performance was investigated and the best operation conditions for biosorption were selected (pH 5, temperature 25 °C). The maximum sorption capacity of microelements was determined in single-metal system at pH 5 and 25 °C: Zn(II) 3.30 meq g⁻¹, Cu(II) 1.77 meq g⁻¹, Co(II) 1.75 meq g⁻¹, Cr(III) 1.74 meq g⁻¹, Mn(II) 0.764 meq g⁻¹. Biosorption experiments were also carried out in multi-metal system. The biomass of C. vulgaris enriched with microelements via the process of biosorption in both single- and multi-metal system was discussed in terms of preparation of feed supplement for laying hens and piglets. The experiments showed that 1 kg of conventional feed for laying hens can be supplemented with 0.20 g of the biomass enriched with microelements and for piglets with 0.15 g of the preparation.     

Characterization of the Newly Isolated Lytic Bacteriophages KTN6 and KT28 and Their Efficacy against Pseudomonas aeruginosa Biofilm

We here describe two novel lytic phages, KT28 and KTN6, infecting Pseudomonas aeruginosa, isolated from a sewage sample from an irrigated field near Wroclaw, in Poland. Both viruses show characteristic features of Pbunalikevirus genus within the Myoviridae family with respect to shape and size of head/tail, as well as LPS host receptor recognition. Genome analysis confirmed the similarity to other PB1-related phages, ranging between 48 and 96%. Pseudomonas phage KT28 has a genome size of 66,381 bp and KTN6 of 65,994 bp. The latent period, burst size, stability and host range was determined for both viruses under standard laboratory conditions. Biofilm eradication efficacy was tested on peg-lid plate assay and PET membrane surface. Significant reduction of colony forming units was observed (70-90%) in 24 h to 72 h old Pseudomonas aeruginosa PAO1 biofilm cultures for both phages. Furthermore, a pyocyanin and pyoverdin reduction tests reveal that tested phages lowers the amount of both secreted dyes in 48-72 h old biofilms. Diffusion and goniometry experiments revealed the increase of diffusion rate through the biofilm matrix after phage application. These characteristics indicate these phages could be used to prevent Pseudomonas aeruginosa infections and biofilm formation. It was also shown, that PB1-related phage treatment of biofilm caused the emergence of stable phage-resistant mutants growing as small colony variants.     

Prenatal Stress Enhances Excitatory Synaptic Transmission and Impairs Long-Term Potentiation in the Frontal Cortex of Adult Offspring Rats

The effects of prenatal stress procedure were investigated in 3 months old male rats. Prenatally stressed rats showed depressive-like behavior in the forced swim test, including increased immobility, decreased mobility and decreased climbing. In ex vivo frontal cortex slices originating from prenatally stressed animals, the amplitude of extracellular field potentials (FPs) recorded in cortical layer II/III was larger, and the mean amplitude ratio of pharmacologically-isolated NMDA to the AMPA/kainate component of the field potential—smaller than in control preparations. Prenatal stress also resulted in a reduced magnitude of long-term potentiation (LTP). These effects were accompanied by an increase in the mean frequency, but not the mean amplitude, of spontaneous excitatory postsynaptic currents (sEPSCs) in layer II/III pyramidal neurons. These data demonstrate that stress during pregnancy may lead not only to behavioral disturbances, but also impairs the glutamatergic transmission and long-term synaptic plasticity in the frontal cortex of the adult offspring.     

DNA Base Pair Resolution Measurements Using Resonance Energy Transfer Efficiency in Lanthanide Doped Nanoparticles

Lanthanide-doped nanoparticles are of considerable interest for biodetection and bioimaging techniques thanks to their unique chemical and optical properties. As a sensitive luminescence material, they can be used as (bio) probes in Förster Resonance Energy Transfer (FRET) where trivalent lanthanide ions (La³⁺) act as energy donors. In this paper we present an efficient method to transfer ultrasmall (ca. 8 nm) NaYF₄ nanoparticles dispersed in organic solvent to an aqueous solution via oxidation of the oleic acid ligand. Nanoparticles were then functionalized with single strand DNA oligomers (ssDNA) by inducing covalent bonds between surface carboxylic groups and a 5’ amine modified-ssDNA. Hybridization with the 5’ fluorophore (Cy5) modified complementary ssDNA strand demonstrated the specificity of binding and allowed the fine control over the distance between Eu³⁺ ions doped nanoparticle and the fluorophore by varying the number of the dsDNA base pairs. First, our results confirmed nonradiative resonance energy transfer and demonstrate the dependence of its efficiency on the distance between the donor (Eu³⁺) and the acceptor (Cy5) with sensitivity at a nanometre scale.     

Substance P and Chronic Pain in Patients with Chronic Inflammation of Connective Tissue

Objective

Evidence suggests that substance P (SP) is involved in chronic joint inflammation, such as the pathogenesis of rheumatoid arthritis and osteoarthritis. The goal of the research was to evaluate the correlation between chronic pain and changes in the SP level in patients with chronic inflammation of the connective tissue.

Methods

Patients with osteoarthritis and rheumatoid arthritis were enrolled in this study. The relationship between chronic pain intensity and the serum SP concentration was evaluated in these groups of patients with osteoarthritis and rheumatoid arthritis.

Results

The results showed a positive correlation between the serum SP concentrations and chronic pain intensity.

Conclusions

1. The SP serum concentration was significantly different between the groups of patients with OA and RA. 2. There was a positive correlation between the serum SP concentration and chronic pain intensity in OA and RA patients.     

Free Extracellular miRNA Functionally Targets Cells by Transfecting Exosomes from Their Companion Cells

Lymph node and spleen cells of mice doubly immunized by epicutaneous and intravenous hapten application produce a suppressive component that inhibits the action of the effector T cells that mediate contact sensitivity reactions. We recently re-investigated this phenomenon in an immunological system. CD8+ T lymphocyte-derived exosomes transferred suppressive miR-150 to the effector T cells antigen-specifically due to exosome surface coat of antibody light chains made by B1a lymphocytes. Extracellular RNA (exRNA) is protected from plasma RNases by carriage in exosomes or by chaperones. Exosome transfer of functional RNA to target cells is well described, whereas the mechanism of transfer of exRNA free of exosomes remains unclear. In the current study we describe extracellular miR-150, extracted from exosomes, yet still able to mediate antigen-specific suppression. We have determined that this was due to miR-150 association with antibody-coated exosomes produced by B1a cell companions of the effector T cells, which resulted in antigen-specific suppression of their function. Thus functional cell targeting by free exRNA can proceed by transfecting companion cell exosomes that then transfer RNA cargo to the acceptor cells. This contrasts with the classical view on release of RNA-containing exosomes from the multivesicular bodies for subsequent intercellular targeting. This new alternate pathway for transfer of exRNA between cells has distinct biological and immunological significance, and since most human blood exRNA is not in exosomes may be relevant to evaluation and treatment of diseases.