EC50 Concentration Research Articles

Comprehensive study of acute toxicity using Microtox® bioassay in soils contaminated by lindane wastes

This research studies the acute toxicity of real contaminated soils (topsoil and subsoil) with hazardous chlorinated organic compounds (COCs) from lindane manufacturing wastes. The Microtox® bioassay was used to determine the toxicity of soils (modified Basic Solid Phase Test), soil elutriates (Basic Test), and organic extracts (adapted Organic Solvent Sample Solubilization Test), in which hydrophobic organic compounds are soluble. The acute toxicity of these persistent contaminants (hexachlorocyclohexanes, HCH isomers, as particulate matter in topsoil, and COCs, from dense non-aqueous phase liquid, DNAPL, in subsoil) and the commercial compounds were also measured. Soils tested showed different contaminant levels (topsoil: 0.9–1149 mg/kg and subsoil: 20–9528 mg/kg). Soil contaminants distribution, concentration and acute toxicity were highly related to the contamination source (HCHs or DNAPL). Soils, organic extracts, and subsoil elutriates presented high toxicity, highlighting the need for remediation of these sites. EC50 was calculated in the three-test applied for the soils tested. EC50 vs. COCs concentration in soils and soil elutriates showed an asymptotic trend, explained by the low pollutants solubility in the aqueous phase. Contrarily, EC50 vs. soil COCs concentration was more linear in the case of the organic extracts. This test was the most reliable from statistical analysis. The three methods reveal interesting and complementary information and are necessary for a complete overview of the acute toxicity of contaminated soils.

Synthesis, Antibacterial Activity, and Mechanisms of Novel Indole Derivatives Containing Pyridinium Moieties.

The development of effective antibacterial agents equipped with novel action modes and unique skeletons starting from natural compounds serves as an important strategy in the modern pesticide industry. Disclosed here are a series of novel indole derivatives containing pyridinium moieties and their antibacterial activity evaluation against two prevalent phytopathogenic bacteria, Xanthomonas oryzae pv. oryzicola (Xoc) and X. oryzae pv. oryzae (Xoo). A three-dimensional (3D)-QSAR model was adopted to discover higher activity like title compounds based on the Xoc antibacterial activity of the tested compounds. Compound 43 was consequently designed, and it displayed higher antibacterial activity as expected with the half-maximal effective concentration EC50 values of 1.0 and 1.9 μg/mL for Xoo and Xoc, respectively, which were better than those of the commercial drug thiodiazole copper (TC) (72.9 and 87.5 μg/mL). Under greenhouse conditions, the results of a rice in vivo pot experiment indicated that the protective and curative activities of compound 43 against rice bacterial leaf streak (BLS) and rice bacterial blight (BLB) were 45.0 and 44.0% and 42.0 and 39.3%, respectively, which were better than those of the commercial agent thiodiazole copper (38.0 and 37.9%, 38.6 and 37.0%) as well. Scanning electron microscopy images, defense enzyme activity tests, and proteomic techniques were utilized in a preliminary mechanism study, suggesting that compound 43 shall modulate and interfere with the physiological processes and functions of pathogenic bacteria.

Extract of Codiaeum luzonicum Merr. overcomes multidrug resistance in human colon cancer cells by modulating P-glycoprotein

Objective: To investigate anti-multidrug resistance (MDR) activity and safety of the bioactive fraction (CL11) from Codiaeum luzonicum crude leaf extract. Methods: Cytotoxic activity of CL11 against MDR and non- resistant colon cancer cells was assessed using MTT assay. Mode of cell death was investigated by annexin V-propidium iodide staining, TUNEL, and JC-1 assays. To examine mechanism of action, the effect on the expression and function of the MDR-implicated protein P-glycoprotein was tested using Western blotting and calcein assay, respectively. Results: CL11 had an EC50 of 0.18, 1.03 and 38.52 μg/mL against HCT-15, HCT-15/Dox and HCT116, respectively. Cytotoxicity was mediated by inhibition of P-glycoprotein function and expression. The mode of cell death involved mitochondrial membrane depolarization and was mostly non-apoptotic at EC50 concentrations against HCT-15 and HCT-15/Dox. Conclusions: Fraction CL11 of Codiaeum luzonicum induces non- apoptotic cell death in MDR cancer cells by overcoming MDR through inhibition of P-glycoprotein expression and function.

Cell-line and culture model specific responses to organic contaminants in house dust: Cell bioenergetics, oxidative stress, and inflammation endpoints

Exposure to organic contaminants in house dust is linked to the development or exacerbation of many allergic and immune disorders. In this work, we evaluate the effects of organic contaminants on different cell bioenergetics endpoints using five different cell lines (16HBE14o-, NuLi-1, A549, THP-1 and HepG2), and examine its effects on lung epithelial cells using conventional 2D and 3D (air-liquid interface/ALI) models. Proposed rapid bioenergetic assays relies on a quick, 40min, exposure protocol that provides equivalent dose-response curves for ATP production, spare respiratory capacity, and cell respiration. Although cell-line differences play an important role in assay performance, established EC50 concentrations for immortalized lung epithelial cells ranged from 0.11 to 0.15mg/mL (∼2 µg of dust in a 96-well microplate format). Bioenergetic response of distinct cell types (i.e., monocytes and hepatocytes) was significantly different from epithelial cells; with HepG2 showing metabolic activity that might adversely affect results in 24h exposure experiments. Like in cell bioenergetics, cell barrier function assay in ALI showed a dose dependent response. Although this is a physiologically relevant model, measurements are not as sensitivity as cytokine profiling and reactive oxygen species (ROS) assays. Observed effects are not solely explained by exposure to individual contaminants, this suggests that many causal agents responsible for adverse effects are still unknown. While 16HBE14o- cells show batter barrier formation characteristics, NuLi-1 cells are more sensitivity to oxidative stress induction even at low house dust extract concentrations, (NuLi-1 2.11-fold-change vs. 16HBE14o- 1.36-fold change) at 0.06µg/mL. Results show that immortalized cell lines can be a suitable alternative to primary cells or other testing models, especially in the development of high-throughput assays. Observed cell line specific responses with different biomarker also highlights the importance of careful in-vitro model selection and potential drawbacks in risk assessment studies.

Discovery of Novel Cinnamide Fungicidal Leads with Optical Hydroxyl Side Chain.

In order to overcome the resistance of phytopathogens to commercial fungicides, a series of optical 2-methyl-2,3-diol-5-pentyl-based cinnamamide derivatives were rationally designed, synthesized, characterized, and evaluated for their in vitro and in vivo fungicidal activities. The bioassay results indicated that the EC50 (concentration for 50% of maximal effect) values of (R)-11f, (R)-11m, (S)-11m and (R)-11n were 0.16, 0.28, 0.41 and 0.47 µg/mL in the in vitro evaluation against Sclerotinia sclerotiorum, respectively, while compounds (R)- and (S)-11i, (R)- and (S)-11j exhibited excellent in vivo fungicidal activity against Pseudoperonspera cubensis with inhibition rates of 100% at 400 μg/mL. These findings supported the idea that optical 2-methyl-2,3-diol-5-pentyl-containing cinnamamides (R)- and (S)-11i, (R)- and (S)-11j with 2-chloro-4-trifluoromethyl aniline and 2-(4-chlorophenyl) aniline showed excellent in vivo fungicidal activity against S. sclerotiorum and P. cubensis and were promising fungicide candidates.

Biological characterization and in vitro fungicide screenings of a new causal agent of wheat Fusarium head blight in Tibet, China.

Wheat (Triticum aestivum L.) is an important cereal crop, widely grown throughout the temperate zones, and also suitable for cultivation at higher elevations. Fusarium head blight (FHB) is a highly destructive disease of wheat throughout the globe. In July 2020, serious wheat FHB symptoms were observed in open fields located in Linzhi City, southeast of Tibet, China. The causal agent was identified as Fusarium avenaceum (Fr.) Sacc. by amplification and sequencing of the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (EF-1α) gene, and RNA polymerase II subunit (RPB-2) gene, as well as by morphological characterization. Koch’s postulates were confirmed by a pathogenicity test on healthy spikes, including re-isolation and identification. To our knowledge, this is the first report of F. avenaceum causing FHB on wheat in Tibet, China. Moreover, to determine pathogen characteristics that may be useful for future disease management, the utilization of different carbon and nitrogen resources, temperature, light, and ultraviolet (UV) irradiation on mycelium growth and conidia germination were studied. Soluble starch and peptone were the best carbon, and nitrogen source for the pathogen respectively. The optimal temperatures for the pathogen’s mycelium growth and conidia germination were 15–20°C, matching the average temperature during the growing season in Linzhi (Tibet). Meanwhile, alternating 8-h light and 16-h dark was shown to be conducive to mycelia growth, and complete darkness facilitated conidia germination. In addition, UV Irradiation of 48 MJ/cm2, approximately 100 times of the local condition, did not inhibit the germination of conidia. Furthermore, in vitro screening of effective fungicides was conducted. Among the seven tested pesticides, carbendazim showed the best inhibition rate, with an EC50 (concentration for 50% of maximal effect) value of 2.1 mg/L. Propiconazole also showed sufficient inhibitory effects against F. avenaceum, with an EC50 value of 2.6 mg/L. The study provides insights into the newly identified causal agent of wheat FHB in Tibet, China, as well as first pathogen characteristics and promising candidate substances for its management.

Peel Diffusion and Antifungal Efficacy of Different Fungicides in Pear Fruit: Structure-Diffusion-Activity Relationships.

Fungal pathogens can invade not only the fruit peel but also the outer part of the fruit mesocarp, limiting the efficacy of fungicides. In this study, the relationships between fungicide structure, diffusion capacity and in vivo efficacy were evaluated for the first time. The diffusion capacity from pear peel to mesocarp of 11 antifungal compounds, including p-aminobenzoic acid, carbendazim, difenoconazole, dipicolinic acid, flusilazole, gentamicin, kojic acid, prochloraz, quinolinic acid, thiophanate methyl and thiram was screened. The obtained results indicated that size and especially polarity were negatively correlated with the diffusion capacity. Although some antifungal compounds, such as prochloraz and carbendazim, were completely degraded after a few days in peel and mesocarp, other compounds, such as p-aminobenzoic acid and kojic acid, showed high stability. When applying the antifungal compounds at the EC50 concentrations, it was observed that the compounds with high diffusion capacity showed higher in vivo antifungal activity against Alternaria alternata than compounds with low diffusion capacity. In contrast, there was no relationship between stability and in vivo efficacy. Collectively, the obtained results indicated that the diffusion capacity plays an important role in the efficacy of fungicides for the control of pear fruit diseases.

Metabolite profiling and potential antioxidant activity of sixteen fennel (Foeniculum vulgare Mill.) populations growing wild in Tunisia

Sixteen wild Foeniculum vulgare Mill. populations native to Tunisia were investigated based on their phenolic profile of methanol extracts of seeds. The antioxidant potential was evaluated using four model systems such us total antioxidant capacity (TAC), DPPH-radical scavenging activity, ABTS test and reducing power assay (RPA). Results showed significant variations on extracts yields, total polyphenol content (TPC), total flavonoid content (TFC) and CTC (condensed tannin content). LC-MS analysis revealed the identification of 26 phenolic compounds. The cirsiliol was reported for the first time as the predominant phenolic compound in all fennel samples with range from 76.16 to 1021.70 µg/g Dry Extract (DE). The different methanol extracts exhibited strong antioxidant capacities with significant differences among locations. The BeniAyech population showed the highest antiradical capacity with IC50= 23.66 and 7.6 µg/mL for DPPH and ABTS tests, respectively. However, the strongest iron reduction capacity of the methanol extract from El Alia location has reached an efficacy concentration of EC50= 34.16 μg/mL similar to the butylatedhydroxytoluene (BHT) standard. This investigation of Tunisian wild fennel showed the great potential of this species as natural source of bioactive antioxidants molecules for food industry.

Deactivation of STAT3 and ERK and Activation of p38 in Ovarian Cancer Cells Treated with a Small Molecule Inhibitor of PTP4A3 Phosphatase

The Protein Tyrosine Phosphatase of Regenerating Liver‐3, also known as PRL‐3 or PTP4A3, is among the most oncogenic known protein tyrosine phosphatases, promoting cell migration, survival, metabolism, angiogenesis, and tumor formation. These diverse cancer‐associated phenotypic actions are thought to be mediated at least in part by the unique ability of PTP4A3 to function as a positive signal transducer capable of activating STAT3 and ERK1/2 and deactivating p38 kinase. PTP4A3 is significantly upregulated in a majority of human ovarian cancers and is associated with a poor patient prognosis. Our hypothesis is that PTP4A3 phosphatase inhibitors can be effective targeted treatments for ovarian cancer. We previously described a potent, allosteric, small molecule PTP4A3 inhibitor, 7‐imino‐2‐phenylthieno[3,2‐c]pyridine‐4,6(5H,7H)‐dione, which is also known as KVX‐053 or JMS‐053. KVX‐053 shows no significant in vitro inhibition against a panel of protein kinases or protein tyrosine phosphatases other than PTP4A1‐3. KVX‐053 is cytotoxic to chemosensitive and chemoresistant human ovarian cancer cell lines in vitro and has in vivo antitumor activity. The goal of the current study was to examine the impact of a PTP4A3 phosphatase inhibitor on human ovarian cancer STAT3, ERK1/2, and p38 activation. We observed a concentration‐dependent decrease in the activated form of STAT3, namely, Y705 phospho‐STAT3, after a 4 h exposure of A2780 ovarian cancer cells to KVX‐053 in vitro. A 4 h exposure to a concentration of KVX‐053 that reduced A2780 cell viability by 25% (EC25), namely 157 nM, decreased Y705 phospho‐STAT3 levels by 46%. An EC50 (470 nM) or EC90 (4.23 μM) concentration decreased Y705 phospho‐STAT3 levels by 61% and 87%, respectively. STAT3 levels remained unchanged except for a modest decrease with 4.23 μM of KVX‐053. ERK1/2 phosphorylation was decreased 64% with a 4 h treatment of an EC90 concentration of KVX‐053 but not with the EC25 or EC50 concentrations. In contrast, KVX‐053 caused a concentration‐dependent increase in p38 kinase phosphorylation and activation. These results suggest that acute KVX‐053 exposure disrupts the PTP4A3/STAT3, PTP4A3/ERK, and PTP4A3/p38 homeostatic loops, providing additional information about the role of PTP4A3 in cancer cell signaling and survival.

Comparative Toxicity of Herbicide Active Ingredients, Safener Additives, and Commercial Formulations to the Nontarget Alga Raphidocelis Subcapitata.

Chloroacetanilide herbicides are used worldwide to control weeds that affect crops such as corn, soybeans, and cotton. These herbicides are frequently paired with a "safener," which prevents herbicidal damage to the crop without diminishing weed control. Formulated herbicide products that include safeners and other ingredients are infrequently assessed for toxicity. Our goal was to understand the potential toxicity of safeners and herbicide + safener formulations relative to the toxicity of associated active ingredients. We quantified the concentration of safeners in commercially available formulations and tested effects on nontarget algae, Raphidocelis subcapitata, when exposed to individual herbicide active ingredients, safeners, and commercial formulations. The median effective concentrations (EC50s) causing 50% reduction in population growth for the herbicide active ingredients S-metolachlor and acetochlor were 0.046 and 0.003 ppm, respectively. The safeners benoxacor, AD-67, furilazole, and dichlormid were all substantially less toxic than the herbicides and were not toxic at environmentally relevant concentrations. The commercial formulations Dual II Magnum®, Me-Too-Lachlor II®, Harness®, and Surpass EC® all resulted in EC50 values that fell within the 95% confidence interval of the associated active ingredient herbicide. Interestingly, a significant increase in cell size was observed when algae were exposed to all the formulations, herbicides (acetochlor and S-metolachlor), and safener (dichlormid). The safener furilazole caused a significant decrease in cell size, whereas benoxacor and AD-67 had no observed effect on algae cell size. Significant algae cell size effects all occurred at or above the EC50 concentrations for each chemical, suggesting that other morphological effects may be occurring. Importantly, safeners in commercial formulations appeared not to impact toxicity to R. subcapitata compared with the active ingredient alone.Environ Toxicol Chem 2022;41:1466-1476. © 2022 SETAC.

Compositional variations of primary organic aerosol tracers of PM2.5 in Shanghai during the 2019 China International Import Expo

To reflect the changes in pollution sources and evaluate the control efficiency more reasonably, seven groups of PM2.5-bound primary organic aerosol (POA) tracers indicative of pollution sources in urban Shanghai were analyzed before (BP), during (CIIE) and after (AP) the second China International Import Expo (CIIE, October 28–November 17, 2019). Combined with meteorological conditions, correlation analysis among the tracers and diagnostic ratios, the sources and influencing factors of POA tracers were investigated. During CIIE, the concentrations of POA tracers showed a downward trend from 287 ng/m3 in the BP period to 219 ng/m3, while the proportion of POA tracers in PM2.5 increased from 0.58% to 1.0%. The sandstorm during BP caused the high concentrations of PM10 and PM2.5, the temporal variation of the concentrations of monosaccharides and sugar compounds and plant wax n-alkanes (WAX Cn) well reflected the impact of dust. The obvious increase of the relative concentrations of hopanes and steranes to EC during CIIE reflected that the decrease of EC concentration was due to the decrease of emission from sources other than traffic sources. The control of illegal emissions of factories and the decreased biomass burning might contribute to the decrease of EC during the CIIE. The results showed that the variations in POA tracers revealed the changes in pollution sources. Hence, it is necessary to pay attention to the compositional changes in organic aerosols when evaluating the causes of variation in concentration of PM2.5.

Antimicrobial Effects and Active Compounds of the Root of Aucklandia Lappa Decne (Radix Aucklandiae).

The development of new biological fungicides using plant metabolites has become an important direction for pesticide development, and previous studies found that Radix Aucklandiae had a certain inhibitory effect on plant pathogens. In this study, we systematically studied the antimicrobial activity of extracts of Radix Aucklandiae, and the active compounds were isolated, purified and structurally identified. Ethanol extracts of Radix Aucklandiae had different inhibitory effects on seven common plant-pathogenic fungi, with EC50 (concentration for 50% of maximal effect) values ranging from 114.18 mg/L to 414.08 mg/L. The extract at concentration of 1,000 mg/L had a significant control effect on strawberry grey mould and wheat powdery mildew of more than 90%. Three active compounds were isolated and purified from the extract, which were identified as alantolactone, dehydrocostus lactone and costunolide. All three compounds showed significant inhibitory effects on Botrytis cinerea, and the MIC (minimal inhibitory concentration) values were 15.63 mg/L, 3.91 mg/L and 15.63 mg/L. Dehydrocostus lactone also showed obvious inhibitory effect on Fusarium graminearum with an MIC value of 62.25 mg/L. The extract of Radix Aucklandiae has high antimicrobial activity against some common plant-pathogenic fungi, and the work lays a foundation for the development of extracts of Radix Aucklandiae as botanical fungicides.

Characterization of vitellogenin concentration in male fathead minnow mucus compared to plasma, and liver mRNA.

The objective of this study was to characterize vitellogenin (VTG) protein in male fathead minnow (Pimephales promelas) mucus compared with more conventional measures in plasma and mRNA isolated from liver. To assess the intensity and duration of changes in mucus VTG concentrations, male fathead minnows were exposed to 17α-ethinylestradiol (EE2) for 7 days with a subsequent depuration period of 14 days. The experiment was conducted in a flow-through system to maintain a consistent concentration of EE2 at a nominal EC50 concentration of 2.5 ng/L and high concentration of 10 ng/L as a positive control. Mucus, plasma and liver were sampled at regular intervals throughout the study. Relative abundance of vtg mRNA increased after 2 days of exposure and returned to control levels after 4 days of depuration. VTG protein concentration displayed similar induction kinetics in both mucus and plasma, however, it was found to be significantly increased after 2 days of exposure using the mucus-based assays and 7 days with the plasma-based assay. Significantly elevated levels of VTG were detected by both assays throughout the 14-day depuration period. The elimination of the laborious plasma collection step in the mucus-based workflow allowed sampling of smaller organisms where blood volume is limiting. It also resulted in significant gains in workflow efficiency, decreasing sampling time without loss of performance.

Single and mixture toxicity of selected pharmaceuticals to the aquatic macrophyte Lemna minor.

Plants represent uncommon targets to evaluate pharmaceuticals toxicity. In this work, Lemna minor was employed as a plant model to determine the toxicity of selected pharmaceuticals, and to assay if such toxicity could be predicted by QSAR models based on green algae. Among eight compounds, measurable toxicity was determined for ketoprofen (EC50 = 11.8 ± 1.9 mg/L), fluoxetine (EC50 = 27.0 ± 8.7 mg/L) and clindamycin 2-phosphate (EC50 = 57.7 ± 1.7 mg/L). Even though a correlation of r2 = 0.87 was observed between experimental toxicity towards algae and L. minor, QSAR estimations based on algae data poorly predicted the toxicity of pharmaceuticals on the plant. More experimental data for L. minor are necessary to determine the applicability of these predictions; nonetheless, these results remark the importance of measuring experimental ecotoxicological parameters for individual taxa. The toxicity of pharmaceutical binary mixtures (ketoprofen, fluoxetine and clindamycin) revealed in some cases deviations from the concentration addition model; nonetheless these deviations were small, thus the interactions are unlikely to be of severe biological significance. Moreover, the EC50 concentrations determined for these pharmaceuticals are significantly higher than those detected in the environment, suggesting that acute effects on L. minor would not take place at ecosystem level.

Acute and chronic toxicities of prothioconazole and its metabolite prothioconazole-desthio in Daphnia magna

Current research on prothioconazole (PTC), a broad-spectrum triazole fungicide, mainly focuses on its efficacy and residues; only a few studies have been assessing its toxicological effects. Using acute and chronic toxicity tests, we assessed the effects of PTC and its metabolite prothioconazole-desthio (PTCd) on the inhibition of the activity, growth, and reproduction of Daphnia magna. A dose-response relationship was established to determine sensitive biological indicators. In the acute and chronic toxicity tests, the 48-h EC50 (concentration for 50% of the maximal effect) of PTC and PTCd for D. magna were 2.82 and 5.19mg/L and 0.0807 and 0.132mg/L, respectively; in the latter test, PTC was 1.64 times more toxic than PTCd. Acute-to-chronic toxicity ratios were calculated using chronic toxicity data; the ratios were 227 and 27.5 for PTC and PTCd, respectively. Our results indicate that both PTC and PTCd affect the growth and reproduction of D. magna and that the toxicity of PTC is greater than that of PTCd. In conclusion, the metabolites of PTD are toxic to D. magna at certain concentrations, and their environmental risks should not be neglected.

Estimation of median effective effect-site concentration (EC50) during target-controlled infusion of propofol for dilatation and curettage - A prospective observational study.

Background and Aims:Propofol is the drug of choice for sedation in daycare procedures due to its pharmacokinetic properties. Propofol delivery using target-controlled infusion (TCI) pump reduces adverse effects like hypotension and apnoea. In this study, we estimated the median effective effect-site concentration of propofol in patients undergoing dilatation and curettage.Methods:Patients of the American Society of Anesthesiologists physical status class I–III, aged 40–70 years, undergoing elective dilatation and curettage were recruited for the study. All patients received 1 μg/kg fentanyl and 20 mg lignocaine. The first patient received an effect-site concentration of propofol at 4 μg/mL with TCI Schneider pharmacokinetic model. Failure was defined as patient movement at any time during the procedure. According to the ‘BiasedCoin Design’ up-and-down sequential method, the response of the previous patient determined the effect-site concentration of propofol of the next patient. The study was terminated once forty patients completed the procedures successfully. Probit analysis was used to determine EC50.Results:Fifty-three patients were recruited for the study. The various effect-site concentrations of propofol EC50, EC90, and EC95 in providing sedation for dilatation and curettage were 3.38 μg/mL, 4.29 μg/mL, and 4.60 μg/mL, respectively. The incidence of hypotension and apnoea were comparable among the various concentrations of propofol. The mean duration of the propofol infusion was 20 ± 2.86 min. The time to recovery from propofol sedation was 6.97 ± 1.76 min.Conclusion:A median effective effect-site concentration of 3.38 μg/mL of propofol is required to prevent patient movement during uterine dilatation and curettage.

Molecular mechanisms of zinc toxicity in the potworm Enchytraeus crypticus, analysed by high-throughput gene expression profiling

Zinc (Zn) is known to be relatively toxic to some soil-living invertebrates including the ecologically important enchytraeid worms. To reveal the molecular mechanisms of zinc toxicity we assessed the gene expression profile of Enchytraeus crypticus (Enchytraeidae), exposed to the reproduction effect concentrations EC10 and EC50, over 4 consecutive days, using a high-throughput microarray (species customized). Three main mechanisms of toxicity to Zn were observed: 1) Zn trafficking (upregulation of zinc transporters, a defence response to regulate the cellular zinc level), 2) oxidative stress (variety of defence mechanisms, triggered by Reactive Oxygen Species (ROS)), and 3) effects on the nervous system (possibly the primary lesion explaining the avoidance behaviour and also why enchytraeids are relatively susceptible to Zn). The adverse outcome at the organism level (reproduction EC50) could be predicted based on gene expression (male gonad development, oocyte maturation), with Zn at the EC50 affecting processes related to higher stress levels. The gene expression response was time-dependent and reflected the cascade of events taking place over-time. The 1 to 4 days of exposure design was a good strategy as it captured the time for sequence of events towards zinc adverse outcomes in E. crypticus.

Transcriptomics Reveals the Effect of Thymol on the Growth and Toxin Production of Fusarium graminearum.

Fusarium graminearum is a harmful pathogen causing head blight in cereals such as wheat and barley, and thymol has been proven to inhibit the growth of many pathogens. This study aims to explore the fungistatic effect of thymol on F. graminearum and its mechanism. Different concentrations of thymol were used to treat F. graminearum. The results showed that the EC50 concentration of thymol against F. graminearum was 40 μg/mL. Compared with the control group, 40 μg/mL of thymol reduced the production of Deoxynivalenol (DON) and 3-Ac-DON by 70.1% and 78.2%, respectively. Our results indicate that thymol can effectively inhibit the growth and toxin production of F. graminearum and cause an extensive transcriptome response. Transcriptome identified 16,727 non-redundant unigenes and 1653 unigenes that COG did not annotate. The correlation coefficients between samples were all >0.941. When FC was 2.0 times, a total of 3230 differential unigenes were identified, of which 1223 were up-regulated, and 2007 were down-regulated. Through the transcriptome, we confirmed that the expression of many genes involved in F. graminearum growth and synthesis of DON and other secondary metabolites were also changed. The gluconeogenesis/glycolysis pathway may be a potential and important way for thymol to affect the growth of F. graminearum hyphae and the production of DON simultaneously.

Fluoxetine pharmacokinetics and tissue distribution quantitatively supports a therapeutic role in COVID-19 at a minimum dose of 20 mg per day.

Background. Various in vitro studies have shown fluoxetine inhibits multiple variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogen causing the coronavirus disease 2019 (COVID-19) worldwide pandemic and multiple observational clinical studies have shown that patients receiving fluoxetine experienced clinical benefit by lowering the risk of intubation and death. The aim of this study is to conduct population pharmacokinetic dosing simulations to quantify the percentage of patients achieving a trough level for the effective concentration resulting in 50% (EC50) and 90% (EC90) inhibition of SARS-CoV-2 as reported in Calu-3 human lung cells. Methods. Pharmacometric parameter estimates used in this study were obtained from the U.S. FDA website from a new drug application for fluoxetine hydrochloride. A population of 1,000 individuals were simulated at standard fluoxetine antidepressant doses (20 mg/day, 30 mg/day, 40 mg/day, 50 mg/day, and 60 mg/day) to estimate the percentage of the patients achieving a trough plasma level for the EC50 and EC90 SARS-CoV-2 inhibition. All analyses and graphing were conducted in R. Results. By day-10 at 20 mg/day 93.2% and 47% of the population will achieve the trough target plasma EC50 and EC90 concentrations, respectively, which translates to a lung tissue distribution coefficient of 60-times higher EC50 (283.6 ng/ml [0.82 mM]) and EC90 (1390.1 ng/ml [4.02 mM]). Further, by day-10 at an ideal dose of 40 mg/day, 99% and 93% of patients will reach the trough EC50 and EC90 concentrations, respectfully. Lastly, only a dose of 60 mg/day will reach the SARS-CoV-2 EC90 inhibitory concentration in the brain. Conclusion. Overall, with a minimum treatment period of 10-days and a minimum dose of 20 mg/day, this study corroborates in vitro studies reporting fluoxetine inhibiting SARS-CoV-2 titers and also multiple observational clinical studies showing therapeutic benefit of fluoxetine in COVID-19 patients.

Anti-cancer effect of boron derivatives on small-cell lung cancer

BackgroundAnti-cancer activity of boron has been reported. Although many boron derivatives such as boric acid (BA) have been discovered to have anticancer effects, there are many boron derivatives whose anticancer effects have not yet been discovered. Some of these include sodium pentaborate pentahydrate (NaB), which has had limited research on its anticancer effects, and sodium perborate tetrahydrate (SPT), whose anticancer effect has yet to be discovered.The aim of this study was to investigate the anti-cancer effects of boric acid (BA), sodium pentaborate pentahydrate (NaB), and sodium perborate tetrahydrate (SPT) against small-cell lung cancer (SCLC) cell line DMS-114 cells in vitro. MethodsEC50 concentrations and effects of BA, NaB, and SPT on cell survival were detected with an MTS assay. The colony-forming unit (CFU) assay was used to assess their effects on cell colony formation capability. Their effects on apoptosis were determined by an Annexin-V assay. A cell cycle analysis was performed to understand at what phase the cell cycle is arrested. Real-Time PCR (RT-PCR) was used to evaluate the mRNA levels of apoptotic, anti-apoptotic, and tumor suppressor genes. Western blotting was used to determine the protein levels of p53 and Caspase 3. ResultsThe survival rates of DMS-114 cells decreased with BA, NaB and SPT after 72 h of treatment and the EC50 concentrations ​​of DMS-114 and MRC-5 cells differed 5.5-fold in BA treatment, 5,2-fold in NaB treatment and 10-fold in SPT treatment. Colony unit numbers were decreased from 350 to 128, from 320 to 95, and from 430 to 96 in the BA, NaB, and SPT treatment groups, respectively. The apoptosis increased by 10, 19, and 42 percent after treatment with BA, NaB, and SPT for 72 h, respectively. Following 72 h of treatment with BA, NaB, and SPT, some pro-apoptotic and tumor suppressor genes were upregulated and some anti-apoptotic genes were downregulated. Cell cycle arrests were detected at the G2/M phase in the BA, and NaB treatment groups and at the Sub-G1 phase in the SPT treatment group. The protein levels of P53 and Caspase 3 increased with BA, NaB and SPT treatment for 72 h. ConclusionsBA, NaB and SPT show anti-cancer activity in the DMS-114 cell line without damaging MRC-5 cells, and some of the molecular mechanisms are involved in apoptosis and cell cycle arrest.