LC50 Values Research Articles

Development and Application of an In Vitro Drug Screening Assay for Schistosoma mansoni Schistosomula Using YOLOv5.

Schistosomiasis impacts over 230 million people globally, with 251.4 million needing treatment. The disease causes intestinal and urinary symptoms, such as hepatic fibrosis, hepatomegaly, splenomegaly, and bladder calcifications. While praziquantel (PZQ) is the primary treatment, its effectiveness against juvenile stages (schistosomula) is limited, highlighting the need for new therapeutic agents, repurposed drugs, or reformulated compounds. Existing microscopy methods for assessing schistosomula viability are labor-intensive, subjective, and time-consuming. An artificial intelligence (AI)-assisted culture system using YOLOv5 was developed to evaluate compounds against Schistosoma mansoni schistosomula. The AI model, based on object detection, was trained on 4390 images distinguishing between healthy and damaged schistosomula. The system was externally validated against human counters, and a small-scale assay was performed to demonstrate its potential for larger-scale assays in the future. The AI model exhibited high accuracy, achieving a mean average precision (mAP) of 0.966 (96.6%) and effectively differentiating between healthy and damaged schistosomula. External validation demonstrated significantly improved accuracy and counting time compared to human counters. A small-scale assay was conducted to validate the system, identifying 28 potential compounds with schistosomicidal activity against schistosomula in vitro and providing their preliminary LC50 values. This AI-powered method significantly improves accuracy and time efficiency compared to traditional microscopy. It enables the evaluation of compounds for potential schistosomiasis drugs without the need for dyes or specialized equipment, facilitating more efficient drug assessment.

Toxicity Assessment of Four Commonly Used Insecticides to the Corn-Infesting Rice Weevil (Coleoptera: Curculionidae)1

Abstract Rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), is one of the most significant pests of corn (Zea mays L.) and other stored grains. Historically, synthetic insecticides have been widely used to control pest populations due to their effectiveness, convenience of storage and application, and persistent activity. This study aimed to assess the toxicity profiles of four commonly used insecticides, including pirimiphos-methyl, deltamethrin, deltamethrin plus (S)-methoprene, and malathion, to rice weevil adults. The weevils were exposed to a range of concentrations of each insecticide to generate concentration–mortality response curves and median lethal concentrations (LC50) of each insecticide. Pirimiphos-methyl exhibited the highest toxicity to the adult weevils, with an LC50 of 0.74 ppm (95% confidence limit [CL], 0.57–0.92). Based on nonoverlapping 95% CLs, we determined that the LC50 of pirimiphos-methyl was significantly lower than the LC50 of malathion (7.08 ppm [95% CL, 5.44–9.01]), deltamethrin (9.11 ppm [95% CL, 6.89–12.6]), and deltamethrin plus (S)-methoprene (13.94 ppm [95% CL, 9.71–18.60]). Thus, the relative toxicity of these four insecticides to adult rice weevils was pirimiphos-methyl > malathion > deltamethrin > deltamethrin plus (S)-methoprene. We subsequently compared the LC50 value of each insecticide with that of the label-recommended application rate and found that only malathion aligned with the recommended label rate. These findings could prove useful in refining application rates for the effective control of rice weevils infesting stored grains.

Insecticidal potential of botanical extracts for management of, the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae)

BackgroundBactrocera dorsalis (Hendel) poses a significant threat to global fruit production and quality, including in Pakistan, where it causes substantial losses. Traditional control methods have heavily relied on the indiscriminate and imprudent use of insecticides, leading to challenges such as insecticide resistance, environmental pollution, fruit contamination, and health risks. This study explores the insecticidal potential of seven selected botanicals: Artemisia vulgaris L., Capparis spinosa L., Mentha longifolia, Mentha piperita, Peganum harmala, Eucalyptus globulus, and Callistemon viminalis, each at three different concentrations (10mL, 20mL, and 30mL), against Bactrocera dorsalis (B. dorsalis). Two in vitro experiments involving the application of plant extracts mixed with protein bait and direct spray were conducted.ResultsBoth experimental results demonstrated a direct correlation between the concentration of plant extract and the mortality of B. dorsalis. In the plant extract mixed with protein bait, results recorded after 96 h at 10 mL ranged from 8.667 ± 1.52–47.000 ± 3.00, at 20 mL from 18.667 ± 1.52–53.667 ± 6.02, and 30 mL from 26.000 ± 5.29- 67.667 ± 2.08. Meanwhile, for direct spray, mortality ranged from 2.333 ± 1.15–32.333 ± 6.80 at 10 mL, 1.000 ± 1.00–42.667 ± 7.02 at 20 mL, and 9.667 ± 2.30–61.333 ± 8.50 at 30 mL, respectively. The plant species exhibiting the highest toxic potential against the respective pests was C. viminalis, followed by A. vulgaris L. In contrast, the least toxic effect was observed in Eucalyptus globulus at all concentrations. The highest mean mortality and repellence % were recorded in C. viminalis and E. globulus in both experimental trials. The results revealed the highest efficacy of C. viminalis with an LC50 value of 9685.15 and 19,909.11 ppm, for the extract mixed with protein bait and sprayed, was obtained, respectively, the most toxic to the pest followed by the extracts E. globulus and C. spinosa L.ConclusionBased on our experimental results, it is concluded that C. viminalis and A. vulgaris L. are an effective alternative for the management of B. dorsalis.

Rhodium complex [RhLI2]I: a novel anticancer agent inducing tumor inhibition and apoptosis

Numerous chemotherapeutic agents are currently employed in cancer treatment, but many are associated with significant side effects. This study aims to identify a novel anticancer drug that minimizes or eliminates these adverse effects. The anticancer activity of the Rhodium (III) complex cis-[RhLI2]I was evaluated through both in vivo and in vitro functional assays. Apoptosis in cancer cells post-treatment was assessed using microscopy and gene expression analysis. In cytotoxicity screening via the brine shrimp lethality bioassay, the compound exhibited an LC50 value of 25.90 µg/mL (P < 0.001). It also achieved an 88.96% inhibition of cell growth (P < 0.001), an 82.39% increase in lifespan (P < 0.001), and a significant reduction in tumor weight at a dosage of 200 µg/kg in Ehrlich ascites carcinoma (EAC)-bearing Swiss albino mice. Restoration of hematological parameters, such as RBC, WBC, and hemoglobin levels, was observed in treated tumor-bearing mice compared to untreated EAC-bearing mice. The compound inhibited the growth and proliferation of breast cancer (MCF7) cells in a dose-dependent manner, achieving a maximum inhibition of 88.9% at 200 µg/mL. Apoptotic induction in MCF7 cells occurred through the upregulation of p53, Bax, caspase-3, -8, and -9, alongside the downregulation of the anti-apoptotic protein Bcl-2. No long-term adverse effects on hematological or biochemical parameters or tissue levels were observed in the mice. Given these findings, this compound demonstrates significant cytotoxic effects and has the potential to serve as a promising chemotherapeutic agent, warranting further investigation at more advanced stages.

Larvicidal Toxicity of Octopus cyanea Ink against Aedes aegypti Larvae

Background: The Aedes aegypti mosquito is a key vector for serious diseases such as dengue, Zika, chikungunyaand yellow fever, necessitating effective control measures. Conventional chemical insecticides face challenges such as insecticide resistance and environmental impact, prompting the exploration of alternative strategies. This study investigates the larvicidal potential of Octopus cyanea ink against Ae. aegypti larvae as a natural biocontrol agent. Methods: O. cyanea ink, known for its complex bioactive compounds, was tested against fourth instar larvae of Ae. aegypti after 24 and 48 hours of exposure at different concentrations ranged between 100-600 ppm. Result: The study revealed a dose- and time-dependent increase in larval mortality, with the highest concentration (600 ppm) causing up to 98.33% mortality within 48 hours. Probit analysis indicated LC50 values of 311.31 ppm at 24 hours and 180.11 ppm at 48 hours, suggesting increased efficacy over time. The findings underscore the potential of O. cyanea ink as an eco-friendly, natural larvicide, offering a promising alternative to synthetic chemicals. The study highlights the need for further research, including field trials and chemical characterization of the ink, to develop new sustainable approaches for mosquito control and to combat the growing issue of insecticide resistance in Ae. aegypti populations.

Enhancement of Tolerance against Flonicamid in Solenopsis invicta Queens through Overexpression of CYP6AQ83.

Solenopsis invicta, an extremely destructive invasive species, has rapidly spread in China, with queens exhibiting chemical tolerance. In this study, bioassays were conducted on S. invicta colonies collected in Nanchong, revealing that the LC50 value of flonicamid for queens (3.91 mg/L) was significantly higher than that for workers (1.07 mg/L). Comparative analysis of transcriptomes of workers and queens treated with flonicamid revealed that differentially expressed genes (DEGs) were significantly enriched in the metabolism of xenobiotics by cytochrome P450 and drug metabolism by cytochrome P450 pathways. Based on the screening of transcriptome data, CYP6AQ83 might be involved in the detoxification metabolism of flonicamid in queens. After RNA interference, the sensitivity of queens to flonicamid was significantly increased by 30% in the treatment of the dsCYP6AQ83 group. Furthermore, heterologous overexpression of CYP6AQ83 in Drosophila melanogaster also significantly enhanced the tolerance against flonicamid. These results indicated that the overexpression of CYP6AQ83 in the queen enhances the tolerance against flonicamid.

Novel Meta-Diamide Derivatives Bearing Triazole: Design, Synthesis, and Bioactivity.

In searching for novel insecticide lead, 20 new meta-diamide compounds containing triazole were designed and synthesized regarding cyproflanilide as lead compound. All the compounds were characterized by 1H NMR, 13C NMR, and High-resolution mass spectra (HR MS). In preliminary bioassay, we found that one of the compounds: N-(cyclopropylmethyl)-N-(5-((2,6-dibromo-4-(1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl)phenyl)carbamoyl)-2-(1H-1,2,4-triazol-1-yl)phenyl)-6-(trifluoromethyl) nicotinamide (16a) had high activity against the target organism Plutella xylostella at 1mg/L and against the target organism Mythimna separata at 2mg/L. It is obviously superior to the known compounds Ia and Ib, and it is equivalent to cyproflanilide, and the LC50 values of the compound against P. xylostella and M. separata were 0.90mg/L and 0.64mg/L, respectively. It is providing important clues for subsequent structure-activity relationship (SAR) studies. From this, we explored the SAR of these compounds. Through comprehensive analysis of their structural characteristics and insecticidal activity data, we found that different halogen substituents on benzene ring and different aromatic substituents on amino group in the compound had significant effects on insecticidal activity. This has certain guiding significance for further structural optimization and activity enhancement.

Investigation of Anxiolytic, Cytotoxic, and Anthelmintic Activities of the Leaves of Calamus rotang L. (Arecaceae)

Nature has always blessed humanity with numerous means of remedy for treating a wide range of diseases. Since different parts of Calamus rotang L. have several ethnopharmacological activities, including CNS depressant and anthelmintic action, its crude methanol extract of leaves was used to investigate its anxiolytic, cytotoxic, and anthelmintic activities. The methanol was selected because it could extract a vast range of phytoconstituents. The anti-anxiety activities of CRME were investigated on the Swiss albino mice model through a hole board and elevated plus maze test, while the cytotoxic and anthelmintic activities were screened on brine shrimps and Pheretima posthuma, respectively. The current study exhibited that crude methanol extract of C. rotang L. leaves had a significant (p&gt;0.001) and dose-dependent effect against anxiety on mice model of hole board and elevated plus maze when compared with that of control. Furthermore, crude methanol extract of C. rotang L. leaves showed a concentration-dependent mild anthelmintic effect exhibiting no cytotoxicity (LC50 value of 1.02 mg/ml). Thus, the present study revealed the potential of crude methanol extract of C. rotang L. leaves as an excellent anxiolytic agent having a mild anthelmintic effect with no cytotoxicity. Chittagong Univ. J. B. Sci. Vol. 12 (1 &amp; 2): 19-26, 2024

Phytochemical Screening and Pharmacological Evaluation of Merremia vitifolia (Burm.f.) Hallier f. Leaf Extract

The current investigation aimed to explore the various pharmacological properties of methanol extracts of Merremia vitifolia (Burm.f.) Hallier f. leaves (MEMV). Phytochemical analysis was performed following the established procedures. Using the hole board device, the anxiolytic action was measured. The oral glucose tolerance test (OGTT) was used to evaluate the hypoglycemic activity and the castor oil-induced diarrhea method was employed to explore the antidiarrheal activity in Swiss albino mice. Utilizing the brine shrimp lethality assay (BSLA), cytotoxicity was evaluated. In this study, it was observed that MEMV contained a number of active secondary metabolites such as triterpenes, alkaloids, glycosides, flavonoids, phenols and tannins. Compared to the control group, MEMV at 200 mg/kg and 400 mg/kg (p&lt;0.05; p&lt;0.001) significantly increased the number of head dips. However, MEMV showed potential as a dose-dependent anxiolytic medication. In the OGTT procedure, MEMV exhibited possible hypoglycemic effects that persisted for a shorter period. After 30 minutes of glucose load, the 200 mg/kg dose of MEMV significantly lowered blood glucose levels by 60.70% (p&lt;0.001), in comparison to the control group. When compared to standard loperamide (p&lt;0.001), the MEMV at both doses (200 mg/kg, 400 mg/kg) significantly (p&lt;0.001) inhibited the total number of defecations during the testing period in the castor oil-induced antidiarrheal test. During the BSLA test, the LC50 values of MEMV were found to be 2.882 µg/mL. In comparison to the control group, MEMV demonstrated a good cytotoxic effect. To conclude, our research revealed that the plant extracts have potential anxiolytic, hypoglycemic, antidiarrheal, and cytotoxic properties. Chittagong Univ. J. B. Sci. Vol. 12 (1 &amp; 2): 35-44, 2024

Phytochemical Screening and Evaluation of the Anxiolytic and Cytotoxic Potential of the Leaves and Stem of Ocimum basilicum Linn. var. pilosum (Willd.) Benth.

This research investigated the qualitative screening of phytochemicals, anxiolytic and cytotoxic potentials of crude methanol extracts of the leaves (MEL) and stem (MES) of Ocimum basilicum Linn. var. pilosum (Willd.) Benth is a new variant of sweet basil herb. For the solvent extraction process, methanol was selected due to its ability to solubilize both polar and non-polar plant constituents. Phytochemical analysis was carried out by using the established methods. The anxiolytic activity was assessed on Swiss albino mice using the hole board apparatus, and cytotoxicity was measured using the brine shrimp lethality assay. The current results showed that MEL and MES contained several active secondary metabolites, including alkaloids, glycosides, flavonoids, phenols, tannins, triterpenes, and resins. MEL (200, 400 mg/kg) and MES (400 mg/kg) were found to be significantly (P &lt; 0.001) effective anxiolytic agents as compared to the negative control group. In the case of cytotoxicity activity, MEL showed an LC50 value of 244.45 µg/ml (standard 0.16 µg/ml), indicating cytotoxic potential compared to the negative control. Thus, the findings revealed that MEL and MES were excellent anxiolytic agents with a moderate cytotoxic potential. Chittagong Univ. J. B. Sci. Vol. 12 (1 &amp; 2): 27-34, 2024

Sustainable management of potato tuber moth in storages using entomopathogenic fungi and an ectoparasitic mite.

The potato tuber moth (PTM), Phthorimaea operculella, is an economically important pest of potato crops worldwide. So far, the application of chemical pesticides is the major measure to manage PTM, but it induces serious deleterious impacts on the environment and human health. Here, we screened the entomopathogenic fungi that are lethal to PTM, and tested their sublethal impacts on PTM development, mortality, and reproduction as well as that of ectoparasitic mite Pyemotes zhonghuajia, a natural enemy of PTM. Among 13 tested entomopathogenic fungal strains in three genera, Beauveria Vuillemin, Cordyceps Fries, and Talaromyces Benjamin, Cordyceps fumosorosea (strain KY1136) and Beauveria bassiana (strain KY1115) caused a significantly higher mortality in PTM eggs, larvae, and pupae. Median lethal concentration (LC50) of both strains prolonged PTM immature development, shortened adult longevity, and reduced fecundity and life table parameters in terms of intrinsic rate of increase (rm), net reproductive rate (R0), and finite rate of increase (λ). The LC50 value of KY1136 (1.9 × 106 spores/mL) was lower than that of KY1115 (9.0 × 106 spores/mL), indicating the greater potential for biological control of PTM by KY1136. Both strains had no significant impact on P. zhonghuajia survival and reproduction. Increasing P. zhonghuajia density reduced PTM feeding and pupation rate, while the combined application of P. zhonghuajia and entomopathogenic fungi had no additional effect in inhabiting PTM feeding and pupation. Entomopathogenic fungal strains Cordyceps fumosorosea KY1136 and Beauveria bassiana KY1115 are the potential biological control agents of PTM, but do not impose a negative impact on the natural enemy. Our study provides insights into the integrated pest management of PTM by combining the entomopathogenic fungi and an ectoparasitic mite. © 2024 Society of Chemical Industry.

Abstract A003: In vitro anticancer activities of some organoplatinum (IV) derivatives

Abstract Recent investigations into organoplatinum (IV) complexes as potential anticancer agents have shown considerable promise. Unlike cisplatin, these compounds are more stable in physiological environments and generally exhibit fewer side effects. Additionally, chelating aromatic ancillary ligands have been found to enhance the intercalation of metal-based agents into tumor DNA. This study aimed to synthesize novel organoplatinum (IV) complexes with chelating aromatic ligands and evaluate their anticancer efficacy through in vitro assays. Five complexes were synthesized: [Pt(CH3)2X2{2,2’-bipyridine-4,4’-R2}] (X = Br, I; R = H, CO2H) and [{Pt(CH3)3}2(μ-I)2(μ-adenine)]. These were characterized by single crystal X-ray diffraction and assessed for anticancer activity. The MTT assays indicated that the [Pt(CH3)2X2{2,2’-bipyridine}] complexes were more cytotoxic to the ZR-75-1 human breast cancer cell line than cisplatin, with LC50 values of 6.1 µM for X = I, 11.5 µM for X = Br, compared to 16.4 µM for cisplatin. Furthermore, the sulforhodamine B assays conducted by the National Cancer Institute's Developmental Therapeutics Program revealed that [Pt(CH3)3}2(μ-I)2(μ-adenine)] was highly effective against various cancer cell lines. Notably, it showed an LC50 value of 5.20 µM against the glioblastoma multiforme SF-539 cell line, whereas cisplatin and temozolomide had LC50 values exceeding 100 µM. Similarly, [Pt(CH3)3}2(μ-I)2(μ-adenine)] had an LC50 value of 5.99 µM against the renal carcinoma RXF-393 cell line, with cisplatin and cabozantinib showing LC50 values above 100 µM. While these results highlight the superior cytotoxicity of the tested organoplatinum (IV) complexes, further research and development are required before these compounds can be considered for commercial use as chemotherapy drugs. Citation Format: William A. Howard. In vitro anticancer activities of some organoplatinum (IV) derivatives [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Optimizing Therapeutic Efficacy and Tolerability through Cancer Chemistry; 2024 Dec 9-11; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(12_Suppl):Abstract nr A003

Physiological characteristics of Bacillus thuringiensis subspecies israelensis with double mutations of cwlE and sigK and its activity against larvae of Culex pipiens pallens

To investigate the physiological characteristics of Bacillus thuringiensis subspecies israelensis (Bti) with double mutations of cwlE and sigK genes and to assess the activity of Bti against larvae of Culex pipiens pallens under different external factors, so as to provide the theoretical evidence for the use of engineered bacteria of Bti for effective mosquito control. B. thuringiensis wild-type strain Bt-59 and Bt-59 strain with cwlE mutation [Bt-59 (ΔcwlE)] were cultured in nutrient broth media for 24 hours, and Bt-59 strains with sigK mutation [Bt-59 (ΔsigK)] and double mutations of cwlE and sigK [Bt-59 (ΔcwlE-sigK)] were cultured in nutrient broth media for 48 hours. Then, 5 μL of culture media were transferred to glass sides, and cell morphology and mother cell lysis were observed under an optical microscope. The optical densities of Bti strain culture media were measured at different time points of culture, and the growth curves of Bt-59, Bt-59 (ΔcwlE), Bt-59 (ΔsigK), and Bt-59 (ΔcwlE-sigK) strains were plotted. The differences in carbon source metabolism of four Bti strains were analyzed using the Biolog microplate culture method, and the metabolic activity of these strains was estimated with average well color development (AWCD). The fermentation media of these four Bti strains were diluted into final concentrations of 2.000, 1.000, 0.500, 0.250, and 0.125 μL/L, and the median lethal concentrations (LC50 values) of these four strains against the third instar larvae of Cx. pipiens pallens were determined. In addition, the fermentation media of Bti strains were processed as follows: pH adjusted to 5, 7 and 9; treated at 30, 40 ℃ and 50 ℃ for 12 hours; and exposed to irradiation with ultraviolet lights for 0 hour and 6 hours. Then, 20 third instar larvae of Cx. pipiens pallens were exposed to the above processed fermentation media at a final concentration of 1 μL/L in 200 mL of water at 26 ℃ for 24 hours, and the mosquito mortality was estimated to evaluate the effects of pH, temperature and ultraviolet irradiation on the larvicidal activity of four Bti strains. The growth curves of the Bt-59 strain and its mutants shared a similar changing trend, and both experienced a stable phase 6 hours post-culture. Both spores and crystal proteins were found in Bt-59 and Bt-59 (ΔcwlE) cells, and only crystal proteins were found in Bt-59 (ΔsigK) and Bt-59 (ΔcwlE-sigK) cells. No lysis was found in the cell wall of the Bt-59 (ΔcwlE-sigK) strain, and the crystal protein was embedded in the mother cell. Biolog microplate culture assay showed that the AWCD values of four Bti strains showed a similar changing trend over time, and 33 carbon sources were found to be metabolized by all of the four strains, including dextrin, D-maltose and D-trehalose. The LC50 values of the fermentation media of Bt-59, Bt-59 (ΔcwlE), Bt-59 (ΔsigK), and Bt-59 (ΔcwlE-sigK) strains were 0.60, 0.51, 0.70 μL/L and 0.72 μL/L against Cx. pipiens pallens, respectively. The adjusted mortality of larval Cx. pipiens pallens reduced by 76.60%, 76.00%, 66.67%, and 0 following exposure to the fermentation media of Bt-59, Bt-59 (ΔcwlE), Bt-59 (ΔsigK), and Bt-59 (ΔcwlE-sigK) strains at a pH of 5 relative to at a pH of 7, and the adjusted mortality reduced by 49.02%, 51.06%, 36.36%, and 4.44% following 6-hour exposure to ultraviolet irradiation relative to 0-hour exposure, while the adjusted mortality was 68.33% to 83.33% following treatment with the fermentation media of four Bti strains at different temperatures. Bt-59 (ΔcwlE-sigK) strains do not generate spores, and the absence of cwlE and sigK does not affect the growth, carbon source metabolism, and larvicidal activity of Bti strains against larval Cx. pipiens pallens. Cell wall embedding of Bt-59 (ΔcwlE-sigK) strains may protect larvicidal crystal proteins of Bti strains from external environmental factors, including ultraviolet irradiation, and pH alteration.

Active Components of 16 Essential Oils and Their Fumigation Effects on Galleria mellonella (Lepidoptera: Pyralidae).

The greater wax moth (GWM, Galleria mellonella) is a prevalent pest of the honeybee and a significant risk to both honeybee populations and honeycomb storage. Research on the toxicity of essential oils (EOs) to GWM larvae has provided promising results, although their ovicidal effects and active ingredients require further study. Identifying effective plant compounds is essential for developing insecticides for GWM control. This study assessed the fumigation efficacy of 16 EOs on GWM eggs and fifth instar larvae and determined the effectiveness of these EOs and their primary components for fumigating fifth larvae. Wintergreen, star anise, and clove oils demonstrated significant insecticidal effects on GWM eggs and fifth instar larvae, resulting in a mortality rate exceeding 80% within 48 h. Gas chromatography-mass spectrometry analysis identified methyl salicylate (93.26%), trans-anethole (87.75%), and eugenol (77.75%) as the primary compounds in wintergreen, star anise, and clove oils, respectively. Further toxicity testing confirmed that these compounds were responsible for the observed insecticidal properties of the EOs. Notably, trans-anethole exhibited the lowest LC50 value (25.22 μL/L) against the fifth instar larvae of GWM and significant toxicity against GWM eggs and fifth instar larvae, suggesting its potential as a viable option for the future control of GWM populations.

Toxicological Effects of Pendimethalin: Behavioral Changes and LC50 Analysis in Cyprinus carpio

The pre-emergent herbicide pendimethalin is a selective dinitroaniline compound that interferes with the production of microtubules, potentially contaminating groundwater. The current investigation sought to ascertain the acute toxicity levels and behavioral effects of pendimethalin (30% EC) on Cyprinus carpio. Finney's probit bioassay method estimated the lethal toxicity LC50 values for commercial-grade herbicide pendimethalin on C. carpio. This method entails fitting the data collected from experiments to a probit model, which converts the results obtained (such as mortality rates) into a normal distribution scale. It is a useful tool in toxicological research since it enables more precise estimations of the LC50. The lethal toxicity (LC50) values of pendimethalin to C. carpio exposed to 24, 48, 72 and 96-hr were determined to be 2.83µL/L, 2.59µL/L, 2.39µL/L and 2.20µL/L based on the mortality estimations. Pendimethalin-induced behavioral abnormalities in C. carpio were investigated using sublethal concentrations (i.e., 1/15th, 1/10th, and 1/5th of the 96-hour LC50 value) at intervals of 0, 7, 14, 21 and 28 days. Our research observed behavioral shifts such as reduced general activity, reduced foraging behavior, diminished schooling behavior, reduced reflex stimuli, increased opercula movements, irregular movements, mucus secretion, enhanced breathing rates and increased surface air gulping. Our studies showed that pendimethalin can produce both mortality and behavioral alterations in Cyprinus carpio, offering important insights into the pendimethalin fatal and sub-lethal effects. These results highlight how crucial it is to keep an eye on herbicide poisoning in aquatic habitats since even sub-lethal levels can have an effect on fish behavior and the general health of the ecosystem.

Immunomodulatory Effects of Nellikai Thenural Against Thiamethoxam-Induced Toxicity in Carassius auratus

The accumulation of pesticides in aquatic ecosystems poses significant risks to non-target organisms, particularly fish populations. The study evaluated the protective effects of Nellikai Thenural, a traditional Siddha formulation containing Emblica officinalis and honey, against thiamethoxam-induced toxicity in Carassius auratus (goldfish). The experimental design comprised four groups: control, Nellikai Thenural-treated (733 μg), thiamethoxam-exposed (114.84 mg/L), and co-administered (thiamethoxam + Nellikai Thenural) groups. The LC50 value of Nellikai Thenural was determined at 916 μg/ml/kg body weight through brine shrimp lethality assay. Hematological parameters revealed significant alterations in thiamethoxam-exposed fish, with decreased RBC count, hemoglobin levels, and WBC count. The administration of Nellikai Thenural effectively restored these parameters toward normal levels. Biochemical markers, including plasma proteins, immunoglobulins, and tissue-specific enzymes (ALP, ACP, AST), showed marked improvement in the co-administered group compared to thiamethoxam-exposed fish. Behavioral observations indicated reduced stress responses and improved swimming patterns in fish treated with Nellikai Thenural. The findings demonstrate the potential of Nellikai Thenural as a natural immunostimulant and protective agent against pesticide-induced toxicity in aquatic organisms.

Potential Toxicity of Nine Rare Earth Elements (REEs) on Marine Copepod Tigriopus fulvus.

The present study focused, for the first time, on the adverse effects of nine REEs on the marine copepod Tigriopus fulvus. For this purpose, copepod mortality, immobilization, and naupliar development were assessed. Overall, the results demonstrated that all REEs tested exerted significant adverse effects on T. fulvus, with LC50 values ranging from 0.56 to 1.99 mg/L. Concentration-dependent increases in mortality and immobilization for all tested REEs were observed. Following exposure of nauplii to REEs, a significant slowing of nauplii development was shown with all REEs tested. The results obtained clearly highlight the potential toxicity of REEs, and, in particular, of Lanthanum, which could have consequences on the survival and development of T. fulvus, affecting the copepod population.

Insecticidal Activity of Fatty Acids From the Fruit Extract of Momordica cymbalaria Fenzl Ex Naudin, Has Insecticidal Activities on Mosquito Larvae.

The fruit and other parts of Momordica cymbalaria are known to have medicinal properties. The study investigates the chemical composition and functional groups of M. cymbalaria fruits to assess the insecticidal potential of its bioactive metabolites. In silico approach was used to understand the mechanism behind the insecticidal nature of these metabolites. Ethyl acetate extract has 18 compounds, whereas 20 compounds were identified in methanol using gas chromatography-mass spectroscopy analysis. The extracts contain several functional groups, including alkanes, esters, carboxylic acids, amides and aromatic groups. The insecticidal bioassay using methanol and ethyl acetate extracts of M. cymbalaria on Aedes aegypti and Culex quinquefasciatus mosquito larvae shows that the LC50 value for A. aegypti was 65.7ppm, for C. quinquefasciatus was 96.9ppm and for ethyl acetate and methanol extract is 282.36 and 388.09ppm. Molecular docking of secondary metabolites was performed with five insect proteins, namely, odorant binding protein (OBP), cytochrome P450 (CYP450), prophenol oxidase (PPO), arylalkylamine n-acetyltransferease (aaNAT) and sterol carrier protein (SCP). Results show that methyl 6-cis, 9-cis, 11-trans-octadecatrienoate has high binding affinity with sterol carrier protein (SCP-2) besides showing binding with other insect proteins. The data suggest that methyl 6-cis, 9-cis, 11-trans-octadecatrienoate has multiple insecticidal actions and may serve as a green insecticide.

Botanical Pesticides: Role of Ricinus communis in Managing Bactrocera zonata (Tephritidae: Diptera).

The melon fruit fly, Bactrocera zonata (Coquillett) (Diptera: Tephritidae), is a notorious pest, posing a significant threat to a wide range of fruits and vegetables, leading to substantial agricultural losses worldwide. With growing concerns over chemical pesticide resistance and environmental safety, plant-based insecticides have emerged as eco-friendly and economically sustainable alternatives. In this context, the present study delves into the insecticidal potential of Ricinus communis extracts against B. zonata. The crude extract of R. communis was systematically fractionated using a series of organic solvents with increasing polarities. The fraction demonstrating the highest insecticidal activity was further purified for the isolation of bioactive compounds, employing advanced chromatographic techniques such as Column Chromatography, coupled with state-of-the-art analytical methods including Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR). Bioassays were conducted on B. zonata using the crude extract and its fractions in n-hexane, methanol, and ethyl acetate. Among the isolated compounds, 11,14,17-Eicosatrienoic acid was identified in both the methanol and ethyl acetate fractions. This compound exhibited remarkable insecticidal efficacy, with an LC50 value of 1.36%, a linearity of R2 = 0.64, and a statistically significant probability (p < 0.01). Particularly, 11,14,17-Eicosatrienoic acid emerged as the most potent bioactive agent against B. zonata highlighting its potential as a natural insecticide. These findings underscore the potential of R. communis as a valuable source of bioactive compounds for the sustainable management of B. cucurbitae. This study not only broadens the scope of plant-based pest control strategies but also opens avenues for further exploration of natural compounds in integrated pest management.

Acute toxicity of lampricides to non-target species of concern in the Lake Champlain watershed

Previous research evaluated the toxicity of the lampricide 4-nitro-3-(trifluoromethyl)phenol (TFM) and the combination of TFM with 1 % niclosamide (TFM:1%Nic) to multiple non-target species in the Laurentian Great Lakes. However, few toxicity studies have been conducted for species of concern in Lake Champlain (NY and VT). We conducted 12-hour flow-through toxicity tests with 4 species of native mussels, 6 species of fish, and 1 amphibian species. All tests included exposure of invasive larval Petromyzon marinus (sea lamprey) and were conducted with concentrations that bracketed the predicted minimum lethal concentration required to control larval sea lamprey. Mussel species’ NOEC, LOEC, LC25, and LC50 values ranged from 1.33 to 2.12, 1.71–2.66, 1.75–3.05, and 2.03–4.84 times field determined LC99.9s for sea lamprey (×SLLC99.9) in TFM-only toxicity tests, and from 1.36 to 1.70, 1.68–2.03, 1.86–2.10, and 2.35–2.68 × SLLC99.9 for TFM:1%Nic toxicity tests, respectively. Fish species NOEC, LOEC, LC25, and LC50 values ranged from 0.60 to 1.89, 0.73–2.13, 0.72–2.11, and 0.76–2.18 × SLLC99.9 in TFM-only toxicity tests, and from 0.64 to 2.48, 0.85–3.10, 0.74–3.05, and 0.78–3.16 × SLLC99.9 for TFM:1%Nic toxicity tests, respectively. Amphibian species NOEC, LOEC, LC25, and LC50 values ranged from 0.74 to 0.75, 0.85–0.95, 0.83–0.87, and 0.85–0.91 × SLLC99.9 in TFM-only toxicity tests, and from 0.63 to 0.65, 0.80–0.88, 0.77–0.82, and 0.78–0.87 × SLLC99.9 for TFM:1%Nic toxicity tests, respectively. Generally, mussel species were tolerant, fish sensitivities were variable, and the amphibian species was sensitive to TFM and TFM:1%Nic.