Calculation Of LC50 Research Articles

The synthesis of nanosilver and carbamat to control of Anopheles in malaria endemic areas

Malaria is a national and global problem that really needs attention and Indonesia is the second highest country with the highest number of cases 304,607 in 2021. The use of insecticides at inappropriate doses causes resistance to targets. The aim of this study was to analyze the toxicity of silver nanoparticles to adult Anopheles mosquitoes in malaria endemic areas as well as to determine the lethal concentration (LC50) and to project effectiveness in the lifetime. This research is experimental and uses a post-treatment with control design which was carried out in 4 stages from 2019-2022, which includes laboratory scale tests (2019), field laboratory scale tests (2020), ecological endemic area scale tests (2021), and lifetime tests (2022). Calculation of LC50 in nanosilver toxicity 5965 mg/l and Calculation of life time projections produces the formula Y=(-) 0.012Ln(X)+0.6933. Absorption of silver nanoparticles into the bodies of Anopheles sp. occurs through the spiracles and attacks the Ache enzyme in the central nervous system thereby stopping the working system of the mosquito which will then die. Nanosilver is a very effective herbal insecticide used as an effort to control malaria cases in endemic areas with the right dose and method. For life time, a dose of 1500 mg/l nanosilver effectively kills 74% of adult Anopheles sp mosquitoes on day 32 and it is projected that on 1 year the efficacy of nanomaterials still has an efficacy of 62%).

Involvement of functional senescence in efavirenz-induced toxicity in fruit fly.

We aimed in this article to assess the likeliness of efavirenz to induce functional senescence in Drosophila melanogaster (fruit fly). Ten different concentrations of EFV were mixed with fly food and fed to 3-day-old flies orally for a 7day LC50 calculation. Drug concentrations from LC50 were selected for a 28day survival to determine the duration of treatment for behavioral and biochemical assays. A 5day feeding plan was used to investigate the effects of the drug on organismal, neuromuscular, reproductive, and metabolic senescence. An in silico study was executed to decipher a molecular interaction of Drosophila enzymes glutathione-s-transferase (GST) or acetylcholinesterase (AChE) with EFV. The calculated LC50 of EFV was 118mg/10-g fly diet. The test drug induced a significant (P<0.05) increase in fly mortality, climbing difficulty, and procreative deficits after a 5day oral exposure. Similarly, there were significant (P<0.05) biochemical alterations, which suggested in vivo biochemical damage against total thiols (T-SH), SOD (superoxide dismutase), CAT (catalase), GST, AChE, and MDA (malondialdehyde) in the test flies compared to the control groups. In silico study revealed a significantly (P<0.05) higher binding energy between EFV and the active amino acids of fly AChE and GST when compared to the substrates or standard inhibitors respectively. EFV exhibited ecotoxic potentials evidenced by age-related deficits in the fly's functional integrity such as sluggish movement, procreative deficiency, increased mortality, and oxidant-antioxidant inequality. Results from in silico study suggested antagonism against GST and AChE activities as a likely mechanism of EFV-induced toxicity in the fruit fly.

Classifying chemicals into toxicity categories based on LC50 values- Pros and cons

Classifying chemicals into toxicity categories based on LC50 values- Pros and cons

PERBAIKAN SIFAT LADA (Piper nigrum L.) MENGGUNAKAN MUTAGEN ETHYL METHANE SULPHONATE (EMS)

The study aimed to determine the LC50 using EMS on pepper and obtain a better mutant than the parents. The material used was Indian variety pepper, and the chemical mutagen was Ethyl Methane Sulphonate (EMS). Two hundred Indian Cultivar pepper seeds obtained from community gardens were treated with EMS mutagen at a concentration of 0; 0.2; 0.4; 0.6; 0.8, and 1.0% with 3 hours of immersion. Observations consisted of germination, mutagen damage and agronomic characters. The LC50 calculation was obtained from the regression relationship of dead sprouts with several doses of EMS application which had the best fitting curve with the highest determination value (R2). The results showed that pepper germination was relatively low (62%). The impact of using EMS mutagens causes growth inhibition or even death of sprouts. The higher the concentration, the higher the mortality rate. The relationship between the concentration of mutagens and the mortality rate follows the polynomial equation y = 188.45x – 97.21x2 + 2.71 with a determination value of 99%. Based on the regression model, the LC50 value is 0.3%. In this study, the EMS concentration of 0.2% succeeded obtaining a better mutant pepper than the parental. indicated by increasing the length and width of the cotyledons, respectively, 20 and 24% greater than the control.

Efficacy of Cuscuta campestris Yunck. (Solanales: Convolvulaceae) and Lupinus albus L. (Fabales: Fabaceae) crude extracts against nymphs and adults of Orosanga japonica (Melichar, 1898) (Hemiptera: Ricaniidae)

The planthopper, Orosanga japonica (Melichar, 1898) (Hemiptera: Ricaniidae), is an important agricultural pest of grapevine, kiwifruit and tea in Asia and in some countries of Eastern Europe. The efficacy of the crude extracts of Cuscuta campestris Yunck. (Solanales: Convolvulaceae) and Lupinus albus L. (Fabales: Fabaceae) plants was evaluated under laboratory conditions for control of O. japonica nymphs and adults collected in 2019 from Rize (Turkey). Their toxic efficacies were investigated by two different methods. Fixed-dose death rates were used for LT50 calculation and dosage test results were used for LC50 calculation. Also, the phenolic constituents of active plant extracts were examined using HPLC-DAD. Generally, the LT50 values obtained using ethyl acetate extracts were lower than those with methanol extracts. LT50 values of adults were found lower than in nymphs. The test plants crude extracts had high activity at and below 2 g/L (LC90) for two different plants. HPLC-DAD results showed that the high concentration of kaempferol and quercetin for each extract. Extracts of both plants gave promising results for use in O. japonica control, but more detailed studies on the active constituents of these candidate plants need to be undertaken.

Efficacy of Extractions of Iranian Native Plants against Main Malaria Vector, Anopheles stephensi in Iran for Making Appropriate Formulation for Disease Control

Malaria is the main vector-borne disease worldwide. There are several reports of insecticide resistant in malaria vectors worldwide due to using different insecticides. The aim of this study was to evaluate different native plant extortions against main malaria vector, Anopheles stephensi in Iran for choosing the appropriate plant for formulation and use for vector control. The larvae of An. stephensi were reared in insectary, extraction of plants were carried out at department of Pharmacology. The standard WHO method for biological tests was used for calculation of LC50 and LC90. Probit regration lines were plotted for calculation of LC50 and LC90. In this study several plants including: Mentha spicata, Cymbopogon olivieri, Azadirachta indica, Melia azedarach, Lagetes minuta, Calotropis procera, Eucalyptus camaldulensis, Cupressus arizonica, Thymus vulgaris, Lawsonia inermis, Cedrus deodara, Cionura erecta, Bunium persicum, Carum carvi, Artemisia dracunculus, Rosmarinus officinalis were used. Results showed that Mentha spicata and Eucalyptus camaldulensis, had the lowest and highest LC50 respectively. Results indicated that Mentha spicata and Eucalyptus camaldulensis, had the lowest and highest LC50 respectively. Several other plant extract also showed significant mortality. The formulation of these plants should be prepared and evaluate at the field condition against malaria vectors.

Efectiveness of Ocimum sanctum Linn. Leaves Ethanol Extract on Mortality Raillietina echinobothrida In Vitro

The aims of the research are to prove the anthelmintic effects of Ocimum sanctum Linn. leaves ethanol extract on Raillietina echinobothrida in vitro and to know the value of LC50 and LC90of Ocimum sanctum Linn. leaves ethanol extract. The research used completely randomized design. The research had five treatments and each treatment was done in four replications. The research used 5 Raillietina echinobothrida adult worms for each treatment and all replications. The observation and the recording were done at the first hour until the sixth hour of the research. The Raillietina echinobothrida adult worms were noted dead if there was no movement when they were disturbed by anatomic tweezer, the death of Raillietina echinobothrida were confirmed when they dipped mildly in warm water (50°C) and they showed no movements. The acquired data was analyzed using ANOVA and continued with LSD (5%). The results were Ocimum santum Linn. ethanol extract has the anthelmintic activity in 1.25%, 2.5%, 5% and 10% concentrations. The LC50 and LC90 was analyzed using probit analysis. The results of LC50 calculation were 7.8% at the third hour, 6% at the forth hour, 3.2% at the fifth hour, 2.5% at the sixth hour and the results of LC90 were 6.5% at the fifth hour, 5.2% at the sixth hour. The higher concentration of the extract, the higher anthelmintic activity worked.

Toxicological and behavioral study of two potential antibacterial agents:4-chloromercuribenzoic acid and quercetin on Swiss-albino mice

Global dissemination of carbapenem resistant-Gram negative bacteria (CR-GNB) is supposed to be clinically alarming because it extremely delimits the treatment options against serious infections. 4-Chloromercuribenzoic acid (pCMB) is an efficient metallo-enzyme inhibitor, and quercetin is known for antioxidant, antiviral, anticancer, antimicrobial, and anti-inflammatory activities. These two compounds could be considered as potential candidates for the treatment of CR-GNB mediated infections. Hence, in this study, antibacterial activity of pCMB and quercetin was evaluated against CR-GNB through minimum inhibitory concentration (MIC) determination. Toxicity of pCMB and quercetin was evaluated by LC50 calculation through brine shrimp test (BST) and by investigating hematological, serum biochemical, and histopathological parameters in Swiss-albino mice. Moreover, aggressive–depressive–cognitive behavioral effects of pCMB and quercetin on murine model were evaluated. All the carbapenem resistant isolates (CR-GNB) exhibited MIC values in the range of 4–256 μg/ml, 16–256 μg/ml, and 64–1024 μg/ml for pCMB, quercetin, and meropenem, respectively. BST determined LC50 of pCMB and quercetin at 91.57 ± 0.35 mg/L and 448.45 ± 0.46 mg/L, respectively. Oral administration of low dose of pCMB and quercetin did not induce any significant changes in morphological, behavioral, hematological, serum biochemical, and histopathological parameters among Swiss-albino mice. But, a high dose of pCMB and quercetin exhibited slight toxicity. However, no death was reported for any dosage of pCMB and quercetin. Therefore, pCMB and quercetin might be considered for further investigations on alternative therapeutics to combat against CR-GNB.

Ecotoxicological Method with Marine Bacteria Vibrio anguillarum to Evaluate the Acute Toxicity of Environmental Contaminants.

Bacteria are an important component of the ecosystem, and microbial community alterations can have a significant effect on biogeochemical cycling and food webs. Toxicity testing based on microorganisms are widely used because they are relatively quick, reproducible, cheap, and are not associated with ethical issues. Here, we describe an ecotoxicological method to evaluate the biological response of the marine bacterium Vibrio anguillarum. This method assesses the acute toxicity of chemical compounds, including new contaminants such as nanoparticles, as well as environmental samples. The endpoint is the reduction of bacterial culturability (i.e., the capability to replicate and form colonies) due to exposure to a toxicant. This reduction can be generally referred to as mortality. The test allows for the determination of the LC50, the concentration that causes a 50% decrease of bacteria actively replicating and forming colonies, after a 6 h exposure. The culturable bacteria are counted in terms of colony forming units (CFU), and the "mortality" is evaluated and compared to the control. In this work, the toxicity of copper sulphate (CuSO4) was evaluated. A clear dose-response relationship was observed, with a mean LC50 of 1.13 mg/L, after three independent tests. This protocol, compared to existing methods with microorganisms, is applicable in a wider range of salinity and has no limitations for colored/turbid samples. It uses saline solution as the exposure medium, avoiding any possible interferences of growth medium with the investigated contaminants. The LC50 calculation facilitates comparisons with other bioassays commonly applied to ecotoxicological assessments of the marine environment.

Ecotoxicological Method with Marine Bacteria &lt;em&gt;Vibrio anguillarum&lt;/em&gt; to Evaluate the Acute Toxicity of Environmental Contaminants

Bacteria are an important component of the ecosystem, and microbial community alterations can have a significant effect on biogeochemical cycling and food webs. Toxicity testing based on microorganisms are widely used because they are relatively quick, reproducible, cheap, and are not associated with ethical issues. Here, we describe an ecotoxicological method to evaluate the biological response of the marine bacterium Vibrio anguillarum. This method assesses the acute toxicity of chemical compounds, including new contaminants such as nanoparticles, as well as environmental samples. The endpoint is the reduction of bacterial culturability (i.e., the capability to replicate and form colonies) due to exposure to a toxicant. This reduction can be generally referred to as mortality. The test allows for the determination of the LC50, the concentration that causes a 50% decrease of bacteria actively replicating and forming colonies, after a 6 h exposure. The culturable bacteria are counted in terms of colony forming units (CFU), and the "mortality" is evaluated and compared to the control. In this work, the toxicity of copper sulphate (CuSO4) was evaluated. A clear dose-response relationship was observed, with a mean LC50 of 1.13 mg/L, after three independent tests. This protocol, compared to existing methods with microorganisms, is applicable in a wider range of salinity and has no limitations for colored/turbid samples. It uses saline solution as the exposure medium, avoiding any possible interferences of growth medium with the investigated contaminants. The LC50 calculation facilitates comparisons with other bioassays commonly applied to ecotoxicological assessments of the marine environment.

Development and Characterization of MIR604 Resistance in a Western Corn Rootworm Population (Coleoptera: Chrysomelidae).

mCry3A is one of only four proteins licensed for commercial use in Diabrotica control. Utilizing a colony of western corn rootworm, Diabrotica virgifera virgifera LeConte, selected for resistance to mCry3A, we evaluated how mCry3A resistance was inherited and whether fitness costs were associated with mCry3A resistance. Reciprocal crosses between a selected colony and a control colony were performed; resulting progeny along with parent colonies were evaluated in dose toxicity assays, greenhouse assays, and seedling assays. Dose toxicity assay results were inconclusive, as the highest dose of protein tested did not produce sufficient mortality for accurate LC50 calculation. In whole-plant greenhouse assays on mCry3A-expressing corn, larval relative survival of the selected female × control male reciprocal cross was similar to that of the selected colony, while that of the control female × selected male was intermediate between the mCry3-selected colony and the control colony. However, when adult relative survival in whole-plant greenhouse assays was examined, no significant difference between the reciprocal crosses and the two parent colonies was detected. Heritability calculations based on both larval (0.66) and adult (1.03) survival data indicate that resistance to mCry3A is not inherited in a recessive manner. The selected colony was removed from selection pressure and evaluated after three or eight generations of removal. At three generations of removal from selection, a slight decrease in larval relative survival was detected compared with the selected colony. At eight generations of removal from selection, larval relative survival was comparable with that of the selected colony.

Larvicidal activity of essential oil and methanol extract of Nepeta menthoides against malaria vector Anopheles stephensi

ObjectiveTo investigate the larvicidal activity of essential oil and methanol extract of the Nepeta menthoides (N. menthoides) against main malaria vector, Anopheles stephensi (An. stephensi). MethodsThe essential oil of plant was obtained by Clevenger type apparatus and the methanol extract was supplied with Percolation method. Larvicidal activity was tested by WHO method. Twenty five fourth-instar larvae of An. stephensi were used in the larvicidal assay and four replicates were tested for each concentration. Five different concentrations of the oil and extract were tested for calculation of LC50 and LC90 values. ResultsThe LC50 and LC90 values were determined by probit analysis. LC50 was 69.5 and 234.3 ppm and LC90 was 175.5 and 419.9 ppm for the extract and essential oil respectively. ConclusionsAccording to the results of this study methanolic extract of plant exhibited more larvicidal activity than essential oil. This could be useful for investigation of new natural larvicidal compounds.

Toxicity of Botanical Formulations to Nursery-Infesting White Grubs (Coleoptera: Scarabaeidae)

The toxicity of eight botanically based biopesticides was evaluated against third instars of the scarab larvae (Coleoptera: Scarabaeidae) Popillia japonica Newman, Rhizotrogus majalis (Razoumowsky), Anomala orientalis Waterhouse, and Cyclocephala borealis Arrow. Soil dip bioassays were used to obtain concentration-mortality data 7 d after treatment of larvae, leading to the calculation of LC50 and LC90 values. A wide range in LC50 and LC90 values were exhibited among the formulations. The product Armorex was one of the most active formulations against P. japonica (LC50 = 0.42 ml/liter), R. majalis (LC50 = 0.48 ml/liter), A. orientalis (LC50 = 0.39 ml/liter), and C. borealis (LC50 = 0.49 ml/liter). Armorex is composed of extracts from diverse botanical sources, including 84.5% sesame oil, 2.0% garlic oil, 2.0% clove oil, 1.0% rosemary oil, and 0.5% white pepper extracts. The product Azatin, composed of 3% azadirachtin, also exhibited high toxicity to P. japonica (LC50 = 1.13 ml/liter), R. majalis (LC50 = 0.81 ml/liter), and A. orientalis (LC50 = 1.87 ml/liter). Veggie Pharm is composed of extracts from diverse sources, but this product showed the lowest toxicity to P. japonica (LC50 = 35.19 ml/liter), R. majalis (LC50 = 62.10 ml/liter), A. orientalis (LC50 = 43.76 ml/liter), and C. borealis (LC50 = 50.24 ml/liter). These results document the potential for botanical formulations to control white grubs, but blending extracts from diverse botanical sources does not ensure enhanced biological activity.

Microplates with Integrated Oxygen Sensors for Kinetic Cell Respiration Measurement and Cytotoxicity Testing in Primary and Secondary Cell Lines

This paper presents a cytotoxicity and cell respiration assay that is nondestructive and kinetic. It makes use of 96-well microplates integrated with oxygen sensors. The oxygen signal monitored on-line gives an indication of the cell viability. We show its application for suspension cell lines (Chinese hamster ovary and HL60 cells) as well as adherent (Caco2 cells) and primary (rat hepatocytes) cells using well-known cytotoxic compounds (sodium azide, diclofenac, clozapine, sodium dodecyl sulfate, 2-thiouracil, tamoxifen, and tranylcypromine). The 50% lethality concentration (LC50) obtained from the assay is compared with the standard 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyl-2H-tetrazolium bromide end-point assay. The cells can be grown directly in the plates, and the assay requires no further reagents or processing. The cells can be harvested for further analysis, if required. The on-line dynamic measurement allows the calculation of LC50 as a function of exposure time. LC50 was shown to decrease with time in HL60 cells. The dynamics of this process was considerably different for the three compounds sodium dodecyl sulfate, tamoxifen, and diclofenac, indicating a large potential of application of this method for cell death studies. The assay system can be applied to almost any cell-based systems with little adaptation. The assay is robust, flexible, and applicable for medium- to high-throughput systems requiring only minimal handling and no additional agent.

Toxicity, uptake, and release of the water-soluble fraction of crude oil in different developing stages of the prawn Macrobrachium borellii.

The effects of a water-soluble fraction of light crude oil dissolved in freshwater (WSF) on Macrobrachium borellii exposed at three life stages was evaluated. Adults, larvae (PL), and embryos were exposed to five levels of WSF for 96 h. At 48 and 72 h PL were significantly more sensitive to WSF than adults, though values for 96-h LC50 were not significantly different (1.56 and 1.41 mg/L, respectively). Mortality was never high enough to allow LC50 calculation in embryos, but chronic exposure to WSF increased the mortality near hatching and significantly decreased PL survival compared to the control group. The uptake, accumulation, and depuration of WSF were evaluated in adult prawns (lipid content 1.5% wet wt) exposed to a sublethal concentration for 96 h followed by a 10-d depuration period. Hydrocarbons were rapidly taken up, and after 24 h most of them reached an equilibrium concentration. Increases in the number and alkylation of the aromatic rings enhanced both their accumulation and their retention. When returned to clean freshwater, levels of lighter aromatics dropped rapidly over 12 h. From these studies we conclude that early life stages of M. borellii are not very vulnerable to WSF toxicity, while adults have a rapid uptake and release of most of the contaminating hydrocarbons, probably due to their low lipid levels.

Variations between winter and summer in the toxicity of copper to a population of the mysid Praunus flexuosus

Copper toxicity was tested on a coastal population of the mysid Praunus flexuosus (Muller) from Southampton Water (Southern England) under winter and summer conditions. Ten-day toxicity tests were performed on the different life-cycle stages (female, male and juvenile) present in winter (December/February) and summer (August). The individuals were in winter or summer physiological condition and were exposed to seawater to which 0, 5, 25, 75 and 200 μg l−1 copper was added. There were significantly different copper toxicity effects in winter and summer. In winter mortality was ≤ 1% at all levels of copper exposure, while in summer identical exposure levels caused mortality of up to 93%. The 96 h LC50 was 30.8 μg l−1 copper added in the summer. In winter, the low mortality prevented calculation of LC50. There were differences in responses to copper between the life-cycle stages. Juveniles were more sensitive than adults, and were severely affected within 24 h. Females were more affected than males at lower doses and shorter exposure times.