Calculated EC50 Values Research Articles

Development of a T-cell activation panel using image cytometry in rheumatoid arthritis patient samples

Abstract Rheumatoid arthritis (RA) is an autoimmune disease that results in cartilage damage and bone loss due to chronic inflammation of joints. Treatments for RA include disease-modifying antirheumatic drugs and nonsteroidal anti-inflammatory drugs, as well as the inhibition of activated T-cells. Consequently, there is a need to screen RA patient samples rapidly and effectively to monitor treatment efficacy, disease progression, immune response, and predictive markers. In this work, we developed and demonstrated a multiplex detection method to monitor T-cell activation in a panel consisting of CD3, CD69, CD25, and CD279 (PD-1) surface markers using the Cellaca™ PLX Image Cytometer (Revvity). First, a dosage titration of PHA-P was performed on PBMCs to stimulate T-cell activation. Once stimulated, CD3 positive T-cells were evaluated for CD69, CD25, and the checkpoint molecule CD279. After 24 hours, the percent surface marker positive T-cells and the level of marker expression (median fluorescent intensity values) were used to determine optimal PHA-P dosage. Results showed concentration dependent increases in the expression levels with a calculated EC50 value for PHA-P ranging from 20.16-30.78 µg/mL with a 95% CV based on the CD279 titration curve. The proposed image cytometric surface marker detection method may prove to be an efficient tool to rapidly screen RA patient samples for T-cell activation in the setting of clinical disease treatment or progression.

Physicochemical, functional, and antioxidant properties of black soldier fly larvae protein.

This study explores the multifaceted attributes of black soldier fly larvae protein (BSFLP), focusing on its physicochemical, functional, and antioxidant properties. BSFLP is characterized by 16 amino acids, with a predominant random coil secondary structure revealed by circular dichroism spectra. Differential scanning calorimetry indicates a substantial thermal denaturation temperature of 97.63°C. The protein exhibits commendable solubility, emulsification, and foaming properties in alkaline and low-salt environments, albeit with reduced water-holding capacity and foam stability under elevated alkaline and high-temperature conditions. In vitro assessments demonstrate that BSFLP displays robust scavenging proficiency against 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and hydroxyl radicals, with calculated EC50 values of 1.90±0.57, 0.55±0.01, and 1.14±0.02mg/mL, respectively, along with notable reducing capabilities. Results from in vivo antioxidant experiments reveal that BSFLP, administered at doses of 300 and 500mg/kg, significantly enhances the activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) (p<0.05) while simultaneously reducing malondialdehyde levels in both serum and tissues of d-galactose-induced oxidative stress in mice. Moreover, the protein effectively attenuates oxidative damage in liver and hippocampal tissues. These findings underscore the potential utility of BSFLP as a natural antioxidant source, with applications spanning the food, pharmaceutical, and cosmetic industries. PRACTICAL APPLICATION: Black soldier fly larvae protein emerges as an environmentally sustainable reservoir of natural antioxidants, holding significant promise for the food, pharmaceutical, and cosmetic sectors. Its advantageous amino acid composition, robust thermal resilience, and impressive functional attributes position it as a compelling subject for continued investigation and advancement in various applications.

Metabolic and cardiovascular benefits and risks of 4-hydroxy guanabenz hydrochloride: α2-adrenoceptor and trace amine-associated receptor 1 ligand

Backgroundα2-adrenoceptor ligands have been investigated as potential therapeutic agents for the treatment of obesity. Our previous studies have shown that guanabenz reduces the body weight of obese rats, presumably through its anorectic action. This demonstrates an additional beneficial effect on selected metabolic parameters, including glucose levels. The purpose of this present research was to determine the activity of guanabenz's metabolite—4-hydroxy guanabenz hydrochloride (4-OH-Guanabenz).MethodsWe performed in silico analyses, involving molecular docking to targets of specific interest as well as other potential biological targets. In vitro investigations were conducted to assess the selectivity profile of 4-OH-Guanabenz binding to α-adrenoceptors, along with intrinsic activity studies involving α2-adrenoceptors and trace amine-associated receptor 1 (TAAR1). Additionally, the effects of 4-OH-Guanabenz on the body weight of rats and selected metabolic parameters were evaluated using the diet-induced obesity model. Basic safety and pharmacokinetic parameters were also examined.Results4-OH-guanabenz is a partial agonist of α2A-adrenoceptor. The calculated EC50 value for it is 316.3 nM. It shows weak agonistic activity at TAAR1 too. The EC50 value for 4-OH-Guanabenz calculated after computer simulation is 330.6 µM. Its primary mode of action is peripheral. The penetration of 4-OH-Guanabenz into the brain is fast (tmax = 15 min), however, with a low maximum concentration of 64.5 ng/g. 4-OH-Guanabenz administered ip at a dose of 5 mg/kg b.w. to rats fed a high-fat diet causes a significant decrease in body weight (approximately 14.8% compared to the baseline weight before treatment), reduces the number of calories consumed by rats, and decreases plasma glucose and triglyceride levels.ConclusionsThe precise sequence of molecular events within the organism, linking the impact of 4-OH-Guanabenz on α2A-adrenoceptor and TAAR1 with weight reduction and the amelioration of metabolic disturbances, remains an unresolved matter necessitating further investigation. Undoubtedly, the fact that 4-OH-Guanabenz is a metabolite of a well-known drug has considerable importance, which is beneficial from an economic point of view and towards its further development as a drug candidate.

Assessing ecotoxicity, synergic and antagonistic actions of commonly used components of polymerization mixture in molecularly imprinted polymers preparation process

Increasingly, the challenge is the optimal process of developing a suitable MIP-type sorptive material (taking into account its final form and application area), which is mainly related to the efficiency/effectiveness of the polymerization process. The lack of reaction or its low efficiency generates additional waste and puts it into the environmental cycle. The main aim of the performed research was the estimation of ecotoxicity, and effect of joint action of commonly used components of polymerization mixture applied in MIPs preparation process. The general purpose of this work is to apply bioluminescent bacteria in order to find any potential interactions taking place in two and three-component polymerization mixtures containing selected MIP polymerization components. According to calculated EC50 values for all tested compounds, the toxicity of MIP components to the bioluminescent bacterium Vibrio fischeri can be arranged in decreasing order as follows: DVB > DCM > EDGMA > MAA > TMSPMA > APTES > MMA > TEOS > TMPTA > AA > ACN. Based on obtained results, it was concluded that EGDMA has a strong influence on the antagonistic interactions among mixture components. An overestimation of the toxicity value was noticed for only eight mixtures, where one of the component was DVB, EGDMA, or TEOS.

Risk assessment of the antibiotic amoxicillin on non-toxin-producing strains and toxin-producing strains of Microcystis.

Amoxicillin (AMX) is a common antibiotic used to treat a variety of infectious illnesses in humans and animals, including otitis media, tonsillitis, tonsillopharyngitis, laryngitis, and pharyngitis. The drug ends up in the aquatic ecosystems through animal and human excretion and industrial effluents. The ecological consequences of broad-spectrum antibiotics on non-target species like cyanobacteria are causing considerable concern. The danger of amoxicillin to non-toxin-producing and toxin-producing strains of cyanobacteria is poorly understood. The objective of this study was to analyze the risk (RQ) and physiological effects of AMX on Microcystis aeruginosa EAWAG 198 (non-toxin producing = NTP), Microcystis aeruginosa LE3 (toxin-producing = TP), and Microcystis flos aquae UTEX-LB 2677 (toxin-producing = TP). Our study showed differences in the RQ of the drug to the tested organisms - demonstrating < Microcystis flos aquae UTEX-LB 2677 > Microcystis aeruginosa LE3 > Microcystis aeruginosa EAWAG 198. The calculated EC50 values show that AMX was more toxic to the toxin-producing strains than the non-toxin-producing strains. Amoxicillin led to significant (p < 0.05) growth inhibition and chlorophyll-a content of the exposed cultures. The observed increase in the concentration of intracellular hydrogen peroxide (H2O2) of the exposed cultures at 96h was significant (p < 0.05), demonstrating that the expressed oxidative stress patterns observed during the study were due to AMX. The current study shows significant variation (p < 0.05) in melondialdehyde (MDA) content and the antioxidant enzymes - glutathione-S-transferase (GST) and peroxidase (POD).

A novel electrochemical micro-titration method for quantitative evaluation of the DPPH free radical scavenging capacity of caffeic acid

Abstract In this report, the stoichiometric ratio (R) for the interaction of diphenylpicrylhydrazyl (DPPH) radicals with the antioxidant was employed as an evaluation index for the DPPH radical scavenging activity of antioxidants. This evaluation index was related only to the stoichiometric relationship of DPPH radicals with the antioxidant and had no relationship with the initial DPPH amount and the sample volume, which could offer a solution to the problem of poor comparability of EC50 values under different conditions. A novel electrochemical micro-titration method was proposed for the determination of the stoichiometric ratio (R) for the interaction of DPPH radicals with the antioxidant. This electrochemical micro-titration model was verified using caffeic acid as the DPPH radical scavenger, with the stoichiometric ratio (R) of DPPH radicals to caffeic acid determined to be in the range of 2.003–2.046. The calculated EC50 values were 0.513, 1.011, and 1.981 × 10–5 mol/L for 2.10, 4.05, and 8.02 × 10–7 moL of added DPPH radicals, respectively. The proposed method showed no differences from the conventional method, but had better precision and reliability, and used a smaller amount of sample.

Toxic effects of three perfluorinated or polyfluorinated compounds (PFCs) on two strains of freshwater algae: Implications for ecological risk assessments

Perfluorinated or polyfluorinated compounds (PFCs) continue entering to the environmental as individuals or mixtures, but their toxicological information remains largely unknown. Here, we investigated the toxic effects and ecological risks of Perfluorooctane sulfonic acid (PFOS) and its substitutes on prokaryotes (Chlorella vulgaris) and eukaryotes (Microcystis aeruginosa). Based on the calculated EC50 values, the results showed that PFOS was significantly more toxic to both algae than its alternatives including Perfluorobutane sulfonic acid (PFBS) and 6:2 Fluoromodulated sulfonates (6:2 FTS), and the PFOS-PFBS mixture was more toxic to both algae than the other two PFC mixtures. The action mode of binary PFC mixtures on Chlorella vulgaris was mainly shown as antagonistic and on Microcystis aeruginosa as synergistic, by using Combination index (CI) model coupled with Monte Carlo simulation. The mean risk quotient (RQ) value of three individual PFCs and their mixtures were all below the threshold of 10−1, but the risk of those binary mixtures were higher than that of PFCs individually because of their synergistic effect. Our findings contribute to enhance the understanding of the toxicological information and ecological risks of emerging PFCs and provide a scientific basis for their pollution control.

Preclinical Characterization of ASP2713, a Novel Igβ and FcγRIIB Cross-Linking Antibody, for Prediction of Human Pharmacokinetics and Clinically Effective Dose

Previously, we reported the fundamental pharmacological characteristics of a novel Igβ and Fc gamma receptor IIB cross-linking antibody, ASP2713, as a new treatment option for systemic lupus erythematosus. The aims of the present study were to investigate ASP2713’s characteristics with regard to pharmacological effect, pharmacokinetics (PK), and receptor occupancy, and to predict its human PK and clinically effective dose. The relationship between the concentration and receptor occupancy of ASP2713 for Igβ of B cell receptors was examined using whole blood B cells. Calculated EC50 values in cynomolgus monkeys and healthy volunteers were 0.35 and 0.058 μg/mL, respectively. Dose-dependent inhibition of anti-tetanus toxoid (TTx) antibody production, PK, and receptor occupancy of ASP2713 in TTx-sensitized cynomolgus monkeys suggested a minimally effective dose of 1 mg/kg by single intravenous (IV) administration. Scaling-up of monkey PK parameters to humans by allometric scaling predicted a clinically effective dose of 0.4 mg/kg IV administration at 4-week intervals to maintain a trough concentration in humans which achieved the same receptor occupancy expected at the effective dose in monkeys. This study aids in understanding the characteristics of ASP2713 and can be used as a basis for clinical dose setting.

Combined Effects of Sulfamethoxazole and Erythromycin on a Freshwater Microalga, Raphidocelis subcapitata: Toxicity and Oxidative Stress.

This study investigated the environmental effects of two familiar emerging contaminants, sulfamethoxazole (SMX) and erythromycin (ERY), and their mixture (10:1 w/w) using a green microalga, R. subcapitata. The cell density, pigment content, and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) were analyzed. The calculated EC50 values of SMX, ERY, and their mixture after 96 h were 0.49, 0.044, and 0.06 mg/L, respectively. High concentrations of antibiotics lead to a decrease in chlorophyll a and total carotenoid content, affecting the ability to photosynthesize ROS scavenging capacity. This may be a factor leading to the inhibition of algal growth. When R. subcapitata was exposed to SMX and the mixture, SOD and CAT increased to resist oxidative damage, while the activities of GSH and GST decreased, suggesting that this algae’s antioxidant system was unbalanced due to oxidative stress. R. subcapitata reduced the ERY-induced ROS by increasing the activities of SOD, GSH, and GST. The difference in the contents of nonenzymatic antioxidants and enzyme antioxidants in R. subcapitata indicated the antioxidant mechanisms to SMX and ERY were not identical. This study provides insights into the oxidative stress process in R. subcapitata under different antibiotics.

Inhibition of Phosphodiesterase 5 Promotes the Aromatase-Mediated Estrogen Biosynthesis in Osteoblastic Cells by Activation of cGMP/PKG/SHP2 Pathway.

Mechanical stimulation induces bone growth and remodeling by the secondary messenger, cyclic guanosine 3’, 5’-monophosphate (cGMP), in osteoblasts. However, the role of cGMP in the regulation of estrogen biosynthesis, whose deficiency is a major cause of osteoporosis, remains unclear. Here, we found that the prenylated flavonoids, 3-O-methoxymethyl-7-O-benzylicaritin (13), 7-O-benzylicaritin (14), and 4'-O-methyl-8-isopentylkaempferol (15), which were synthesized using icariin analogs, promoted estrogen biosynthesis in osteoblastic UMR106 cells, with calculated EC50 values of 1.53, 3.45, and 10.57 µM, respectively. 14 and 15 increased the expression level of the bone specific promoter I.4-driven aromatase, the only enzyme that catalyzes estrogen formation by using androgens as substrates, in osteoblastic cells. 14 inhibited phosphodiesterase 5 (PDE5), stimulated intracellular cGMP level and promoted osteoblast cell differentiation. Inhibition of cGMP dependent-protein kinase G (PKG) abolished the stimulatory effect of 14 on estrogen biosynthesis and osteoblast cell differentiation. Further, PKG activation by 14 stimulated the activity of SHP2 (Src homology 2 domain-containing tyrosine phosphatase 2), thereby activating Src and ERK (extracellular signal-regulated kinase) signaling and increasing ERK-dependent aromatase expression in osteoblasts. Our findings reveal a previously unknown role of cGMP in the regulation of estrogen biosynthesis in the bone. These results support the further development of 14 as a PKG-activating drug to mimic the anabolic effects of mechanical stimulation of bone in the treatment of osteoporosis.

FUNGICIDAL ACTIVITY OF GARLIC (Allium sativum) BULBS EXTRACTS AGAINST PLANTS PHATOGENIC FUNGI

Fungicidal activity of garlic (Allium sativum) bulbs extracts against plants phatogenic fungi. Garlic (Allium sativum Linn) has been known to containing organosulphur compounds. These compounds are convinced to possess antibacterial, antifungal, and anticancer activities. The aim of this study is to determine fungicidal activity of garlic bulb extracts against some plants phatogenic fungi. The paper disc agar difussion technique was used to determine fungicidal activity of garlic bulbs extracts. The results showed that in general garlic bulbs extracts provides fungicidal activities. Calculated EC50 values indicated that ethyl acetate garlic bulbs extract was most active against Colletotrichum capsici, Fusarium oxysporum f. sp.capsici, and Sclerotium rolfsi by EC50 values of 48,6; 50,3; and 51.3% respectively. Meanwhile methanolic garlic bulbs extract was the most active against Sclerotium rolfsi with EC50 values of 24,3%.

Interactions of Cd, Cr, Pb, Ni, and Hg in their effects on activated sludge bacteria by using two analytical methods

Since trace metals rarely appear singly in industrial effluents, it is a major challenge to address combined effects of such toxicants on biological units of wastewater treatment plants. The aim of this study was interaction assessment of Cd, Cr, Pb, Ni, and Hg in their effects on activated sludge bacteria using analytical methods. Two mathematical models were used to determine the effect of binary mixtures of Hg, Cd, Cr, Pb, and Ni on activated sludge bacteria using a dehydrogenase enzyme assay. Calculated EC50 values were compared to experimentally observed values of mixtures. Interactive effects were counted to be antagonistic for Hg and Cd, Cd and Pb, Cd and Ni, and Cr and Pb, synergistic for Cd and Cr and Hg and Cr, and additive for other binary mixtures. Maximum toxicity was related to Hg and Cr, Cd and Cr, and Hg and Cd. Physicochemical monitoring of single metals may underestimate hazards arising from these pollutants in environmental samples. Therefore, any possible interaction between metals in such environments should be considered when establishing environmental safety standards.

Toxicity testing of cosmetic ingredients using gametophyte beads of the brown alga Undaria pinnatifida (Laminariales, Phaeophyta)

A 6-h toxicity test of cosmetic ingredients (methylparaben, 2-phenoxyethanol, sodium dodecyl sulfate, triethanolamine) was developed, based on the photosynthetic maximum quantum yield (Fv/Fm) of immobilized gametophytes of the brown macroalga Undaria pinnatifida. From calculated EC50 values, the toxicity ranking of the tested ingredients is: SDS (0.0060%) > MP (0.0634%) > 2-PE (0.2418%) > TEA (3.7023%). Compared to the results from conventional endpoints with other ecotoxicity test organisms, measurements of Fv/Fm is a more sensitive indicator of the toxic effects of cosmetic ingredients. The present technique is simple, rapid, practical, accurate, and requires little space to carry out. This novel method will be a useful tool for assessing the toxicity of a wide range of cosmetic ingredients once the respective sensitivities are fully established.

Antiviral activity of brincidofovir on parvovirus B19

Parvovirus B19 (B19V), a single-stranded DNA virus in the family Parvoviridae, is a human pathogenic virus responsible for a wide range of clinical manifestations. Currently there is no approved antiviral therapy for parvovirus infection. The acyclic nucleoside phosphonate cidofovir (CDV) has been demonstrated to inhibit replication of B19V in vitro. The aim of the present study was to evaluate whether brincidofovir (BCV), a novel lipid conjugate of CDV, could also inhibit B19V replication. Experiments were carried out in erythroid progenitor cells (EPCs) and UT7/EpoS1 cells, infected with B19V and cultured in the presence of different concentrations of BCV and CDV for comparison. The dynamics of viral replication was evaluated by a qPCR-based assay and the extent of inhibition of viral replication exerted by the compounds determined, along with the effect of the compounds on cell viability and cell proliferation rates. Results confirmed that BCV showed significantly higher antiviral activity against B19V compared to CDV in both cell-based systems. For BCV, the calculated EC50 values were in the range 6.6–14.3 μM in EPCs and 0.22–0.63 μM in UT7/EpoS1 cells. In comparison, the EC50 values for CDV were >300 μM in EPCs and 16.1 μM in UT7/EpoS1 cells. Concurrently, the effects on cell viability were observed at a much higher concentration of BCV, with calculated CC50 values in the range 93.4–102.9 μM in EPCs and 59.9–66.8 μM in UT7/Epos1. The antiviral activity was observed specifically with the metabolically active stereoisomer of BCV suggesting that CDV-diphosphate, the metabolite of both BCV and CDV, was the active antiviral. Our results support a selective role for BCV in the inhibition of B19 viral replication.

Combined effects of sulfamethazine and sulfamethoxazole on a freshwater microalga, Scenedesmus obliquus: toxicity, biodegradation, and metabolic fate.

This study investigated the environmental effects of two common emerging contaminants, sulfamethazine (SMZ) and sulfamethoxazole (SMX), and their mixture using a green microalga, Scenedesmus obliquus. The calculated EC50 values of SMZ, SMX, and their mixture (11:1 wt/wt) after 96 h were 1.23, 0.12, and 0.89 mg L-1, respectively. The toxicity of the mixture could be better predicted using a concentration addition model than an independent action model. The risk quotients of SMZ, SMX, and their mixture were >1 during the experiment, indicating their high potential risks on aquatic microorganisms. Despite their toxicity, S. obliquus exhibited 17.3% and 29.3% removal of 0.1 mg L-1 and 0.2 mg L-1 after 11 days of cultivation. The changes of SMZ and SMX removal were observed when combined, which showed a significantly improved removal of SMZ (up to 3.4 folds) with addition of SMX (0.2 mg L-1). The metabolic pathways of SMZ and SMX were proposed according to mass spectroscopic analysis, which showed six metabolites of SMX and seven intermediates of SMZ, formed as a result of ring cleavage, hydroxylation, methylation, nitrosation, and deamination.

Comparative study of the phytotoxicity of ZnO nanoparticles and Zn accumulation in nine crops grown in a calcareous soil and an acidic soil

The increasing use of zinc oxide nanoparticles (ZnO NPs) in agriculture and consumer products has created the need to evaluate their impact on crops. Nine crops were investigated: wheat, maize, radish, bean, lettuce, tomato, pea, cucumber, and beet. The toxic effects of ZnO NPs on seed germination, plant growth, and biochemical parameters, including photosynthetic pigments, protein and malondialdehyde (MDA) content, reactive oxygen species (ROS), enzymes of the antioxidant defence system, as well as the Zn translocation in the plants were investigated using pots containing non-contaminated or ZnO NP-contaminated soil at concentrations of 20, 225, 450, and 900 mg Zn kg−1. Two soils with different physicochemical properties, namely a calcareous soil and an acidic soil, were used. The total and available Zn in the soils were correlated with the Zn in the plants (roots and shoots) and the observed effects. In the calcareous soil, the available Zn was very low and the phytotoxicity was limited to a slight reduction in the biomass for wheat, cucumber, and beet at the highest concentration. Only beet showed an increase in photosynthetic pigments. The parameters related to oxidative stress were affected to different degrees depending on the crop, with the exceptions of maize, lettuce, pea, and beet. In the acidic soil, the available Zn was high, and the germination of bean, tomato, lettuce, and beet, and the growth of most of the crops were seriously affected. The calculated EC50 values (growth) in the acidic soil ranged from 110 to 520 mg Zn kg−1. The photosynthetic pigments and most of the markers of oxidative stress were negatively affected in maize, wheat, bean, and pea. However, these changes were not always associated with a decrease in plant weight. In summary, soil pH and plant species are key factors affecting the Zn availability and phytotoxicity of ZnO NPs.

Methionine gamma lyase from Clostridium sporogenes increases the anticancer effect of doxorubicin in A549 cells and human cancer xenografts.

The anti-cancer efficacy of methionine γ-lyase (MGL) from Clostridium sporogenes (C. sporogenes) is described. MGL was active against cancer models in vitro and in vivo. The calculated EC50 values for MGL were 4.4U/ml for A549, 7.5U/ml for SK-BR3, 2.4U/ml for SKOV3, and 0.4U/ml for MCF7 cells. The combination of doxorubicin (DOX) and MGL was more effective for A549 human lung cancer growth inhibition than either agent alone in vitro and in vivo. MGL reduced the EC50 of doxorubicin from 35.9μg/mL to 0.01-0.265μg/mL. The growth inhibitory effect of DOX + MGL on A549 xenografts in vivo was reflective of the results obtained in vitro. The inhibition rate of tumor growth in the combined arm was 57%, significantly higher than that in the doxorubicin (p = 0.033)-alone arm.

Comparative sensitivity of Crassostrea angulata and Crassostrea gigas embryo-larval development to As under varying salinity and temperature

Oysters are a diverse group of marine bivalves that inhabit coastal systems of the world's oceans, providing a variety of ecosystem services, and represent a major socioeconomic resource. However, oyster reefs have become inevitably impacted from habitat destruction, overfishing, pollution and disease outbreaks that have pushed these structures to the break of extinction. In addition, the increased frequency of climate change related events promise to further challenge oyster species survival worldwide.Oysters' early embryonic development is likely the most vulnerable stage to climate change related stressors (e.g. salinity and temperature shifts) as well as to pollutants (e.g. arsenic), and therefore can represent the most important bottleneck that define populations' survival in a changing environment. In light of this, the present study aimed to assess two important oyster species, Crassostrea angulata and Crassostrea gigas embryo-larval development, under combinations of salinity (20, 26 and 33), temperature (20, 24 and 28 °C) and arsenic (As) exposure (0, 30, 60, 120, 240, 480, 960 and 1920 μg. As L−1), to infer on different oyster species capacity to cope with these environmental stressors under the eminent threat of climate change and increase of pollution worldwide.Results showed differences in each species range of salinity and temperature for successful embryonic development. For C angulata, embryo-larval development was successful at a narrower range of both salinity and temperature, compared to C. gigas.Overall, As induced higher toxicity to C. angulata embryos, with calculated EC50 values at least an order of magnitude lower than those calculated for C. gigas.The toxicity of As (measured as median effective concentration, EC50) showed to be influenced by both salinity and temperature in both species. Nonetheless, salinity had a greater influence on embryos' sensitivity to As. This pattern was mostly noticed for C. gigas, with lower salinity inducing higher sensitivity to As. Results were discussed considering the existing literature and suggest that C. angulata populations are likely to become more vulnerable under near future predictions for temperature rise, salinity shifts and pollution.

Perphenazine and prochlorperazine induce concentration-dependent loss in human glioblastoma cells viability.

Phenothiazine derivatives possess biological properties very useful for cancer therapy, such as antiemetic and sedative activity as well as good blood-brain barrier permeability. Our goal was to determine if perphenazine and prochlorperazine are possessing cytotoxic activity towards U87-MG cells. It has been shown that the analyzed drugs induce concentration-dependent loss in cell viability, what correlates with their chemical structure. The calculated EC50 values for perphenazine (0.98 μM) and prochlorperazine (0.97 μM) are related to their toxic concentrations in human plasma. The obtained results suggest that perphenazine and prochlorperazine may have a potential for the development of new and effective anticancer therapies.

Expression of recombinant α-toxin BmKM9 from scorpion Buthus martensii Karsch and its functional characterization on sodium channels

Scorpion toxins are invaluable pharmacological tools for studying ion channels and potential drugs for channelopathies. The long-chain toxins from scorpion venom with four disulfide bridges exhibit their unusual bioactivity or biotoxicity by acting on the sodium channels. However, the functional properties of most toxins are still unclear due to their tiny amounts in crude venom and their challenging production by chemical and gene engineering techniques. Here, we expressed one of the long-chain α-toxins, BmKM9, found in the venom of the scorpion Buthus martensii Karsch and characterized its pharmacological properties on sodium channels. Unlike previous toxin production, the recombinant BmKM9 (rBmKM9) possessed no additional amino acid residues such as the His-tag and thrombin cleavage site. The refolded toxin could inhibit the inactivation of rNav1.4, hNav1.5 and hNav1.7 sodium channels. Dose-response experiments were further conducted on these channels. The calculated EC50 values were 131.7±6.6nM for rNav1.4, 454.2±50.1nM for hNav1.5 and 30.9±10.3μM for hNav1.7. The channel activation experiments indicated that the rBmKM9 toxin could shift the activation curves of rNav1.4 and hNav1.5 channels toward a more negative direction and present the typical features of a β-toxin. However, instead of the same activation property on sodium channels, the rBmKM9 toxin could result in different inactivation shift capabilities on rNav1.4 and hNav1.5 channels. The V1/2 values of the steady-state inactivation were altered to be more positive for rNav1.4 and more negative for hNav1.5. Moreover, the recovery of the hNav1.5 channel from inactivation was more significantly delayed than that of the rNav1.4 channel by exposure to rBmKM9. Together, these findings highlighted that the rBmKM9 toxin presents the pharmacological properties of both α- and β-toxins, which would increase the challenge to the classical classification of scorpion toxins. Furthermore, the expression method and functional information on sodium channels would promote the potential application of toxins and contribute to further channel structural and functional studies.