LC50 Values Research Articles

Larvicidal properties of essential oils of three Artemisia species against the chemically insecticide-resistant Nile fever vector Culex pipiens (L.) (Diptera: Culicidae): In vitro and in silico studies

Abstract The objective of this study is to determine the larvicidal activity of essential oils (EOs) extracted from three plants of the genus Artemisia against the mosquito Culex pipiens (C. pipiens) using in vitro and in silico studies. A total number of 20 third- and fourth-instar larvae were exposed to various concentrations of the three plants. The LC50 and LC90 values of the tested Artemisia EOs were determined using Probit analysis. In addition, the sensitivity of C. pipiens to these EOs was determined and compared against a standard insecticide, temephos, under laboratory conditions. Furthermore, in silico assessments were carried out on the major constituents to help understand and explain the acquired in vivo results. Gas chromatography analysis identified the major compounds as d-limonene and β-pinene for Artemisia flahaultii, camphor and borneol for Artemisia. aragonensis, and artemisia ketone and caryophyllene for Artemisia annua. A. flahaultii oil showed the highest efficacy against C. pipiens larvae, followed by A. annua oil with average larvicidal activity. In contrast, A. aragonensis EO, composed of a high percentage of monoterpenes, was the least active. Docking simulation indicated that several studied ligands had promising binding scores within the receptor’s binding site compared to the reference insecticide temephos. The obtained results allow us to conclude that A. flahaultii, a species endemic to Morocco, is an excellent means of controlling C. pipiens.

Validating an In-House Method for Assessing Effluent Discharge Toxicity Using Acartia tonsa in the Black Sea

The marine copepod Acartia tonsa is an important bioindicator in ecotoxicological studies due to its sensitivity to pollutants and ecological importance. This research evaluates the effects of reference toxicant on the survival of A. tonsa, aiming to validate an in-house method that assesses the sensitivity and reliability of the species for testing in the Black Sea. A. tonsa individuals were exposed in controlled laboratory conditions to varying 3,5-dichlorophenol (reference toxicant) concentrations, with their survival rates monitored over 48 h. Survival data were analyzed to determine the lethal concentration (LC50), a metric for assessing toxicity. The derived LC50 values offer important benchmarks for assessing the environmental impact of different effluent discharges in the Black Sea region. The outcomes will contribute to improving the accuracy and consistency of environmental monitoring and risk assessment practices in the Black Sea region, ensuring that variations in toxicity data are attributable to environmental factors rather than methodological discrepancies.

The Physiological Effect Of Zinc Oxide (ZnO) Nanopesticide On Aedes aegypti Larvae

Aedes aegypti is responsible for transmitting various mosquito-borne diseases. Recently, there have been concerns about the negative impacts of the insecticides used in vector control including insecticide resistance development in the mosquito population. These circumstances lead to efforts to develop other strategies for controlling mosquito vectors. As technology in nanoparticles advances, zinc oxide (ZnO) nanoparticles have the potential as the alternative for chemical pesticides for mosquito larvicides due to their optical properties and widespread usage in different industries. The purpose of this study was to determine the toxicity of ZnO nanoparticles towards Ae. aegypti larvae and to examine the physiologies of Ae. aegypti mosquito larvae treated with ZnO nanoparticles at LC50 level. Toxicity bioassays were carried out to determine LC50 and LC90 values. The larvae surface and midgut treated with LC50 ZnO were examined using the Scanning Electron Microscope (FESEM) and Dispersive X-ray spectroscopy (EDX). The LC50 and LC90 concentrations of ZnO nanoparticles after 4 hr of direct UV exposure against Ae. aegypti larvae were 49.141 mg/L and 64.195 mg/L, respectively. After exposure to ZnO nanoparticles, Ae. aegypti larvae showed morphological abnormalities, including distorted and shrunk body parts as well as midgut rupture. Overall, the findings suggest that ZnO nanoparticles have the potential to replace chemical pesticides as a means of reducing the populations of Ae. aegypti mosquitoes.

Novel Insecticidal Benzo[4,5]imidazo[1,2-b]pyrazole Derivatives Identified through Ring-Closure Scaffold Hopping on Fipronil.

A series of innovative benzo[4,5]imidazo[1,2-b]pyrazole scaffold containing compounds were rationally designed through a ring-closure scaffold hopping strategy and synthetized with an intermediate derivatization approach. Physicochemical properties analysis indicated the potential pesticide-likeness of the target compounds. The optimal target compound A14 showed relatively good insecticidal activity against P. xylostella, with an LC50 value of 37.58 mg/L, and demonstrated lower acute fish toxicity compared to fipronil. Docking binding mode analysis demonstrated that compound A14 bound to GABAR through a H-bond between the amide group and the residue of 6'Thr. The differences in binding modes between benzo[4,5]imidazo[1,2-b]pyrazole target compounds and fipronil may be a key factor for the reduced insecticidal activities. The elucidated binding mode and SAR profile lay a foundation for the further structural optimization of insecticidal benzo[4,5]imidazo[1,2-b]pyrazole derivatives.

Semi-Preparation and X-ray Single-Crystal Structures of Sophocarpine-Based Isoxazoline Derivatives and Their Pesticidal Effects and Toxicology Study.

Recently, research and development of novel pesticides from natural plant products have received much attention. To accelerate the application of sophocarpine as the agrochemical candidate, a series of novel sophocarpine-based isoxazoline derivatives were prepared by the 1,3-dipolar [2 + 3] cycloaddition reaction of sophocarpine with different chloroximes. Their structures were well characterized by high-resolution mass spectra, infrared spectra, and proton/carbon-13 nuclear magnetic resonance spectra. Eight steric configurations of compounds 5a, 5e', 5f, 5g, 5h, 5i, 5r, and 5u' were further determined by X-ray single-crystallography. Against Aphis citricola Van der Goot, compounds 5n (LD50: 0.032 μg/nymph) and 5o (LD50: 0.024 μg/nymph) exhibited greater than 3.7- and 4.9-fold potent aphicidal activity compared to sophocarpine (LD50: 0.118 μg/nymph). Against Tetranychus cinnabarinus Boisduval, derivative 5g displayed the most promising acaricidal activity with the LC50 value of 0.247 mg/mL, which was 14.2-fold that of sophocarpine. Compounds 5d and 5g also exhibited good control efficacy against T. cinnabarinus. Scanning electron microscopy images indicated that compound 5g can destroy the mite cuticle layer. These results will provide the foundation for the structural modification and use of sophocarpine derivatives as agrochemicals in the future.

Eco-friendly synthesis of silver nanoparticles using Phyllanthus niruri leaf extract: Assessment of antimicrobial activity, effectiveness on tropical neglected mosquito vector control, and biocompatibility using a fibroblast cell line model

Abstract Mosquitoes are rapidly advancing as vectors of several severe diseases. The increasing resistance of mosquitoes and the environmental harm caused by insecticides pose significant challenges for eradicating mosquito vectors. In this study, 18 plant extracts were tested for larvicidal properties against Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi larvae. Phyllanthus niruri (Pn) showed enhanced larvicidal activity in both laboratory and field trials. The biosynthesis of silver nanoparticles (AgNPs) using Pn leaf methanol extract (Pn-LME) was confirmed by UV-visible spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Among various concentrations, 3 mM AgNPs exhibited significant LC90 values of 0.83, 1.46, and 9.11 ppm compared to 9.25, 93.48, and 14.60 ppm of Pn-LME against A. stephensi, C. quinquefasciatus, and A. aegypti, respectively. This indicates the high mortality of mosquito vectors at low AgNP concentrations. Additionally, Pn-AgNPs showed enhanced antibacterial activity and no cytotoxicity in normal fibroblast cells (L929). Field trials demonstrated a 98.70% decrease in mosquito larval density at A. stephensi breeding sites, a 96.55% reduction at C. quinquefasciatus sites, and a 97.85% reduction at Ae. aegypti sites. This study presents an eco-friendly and cost-effective AgNP bio-pesticide synthesized from Pn leaves for controlling and preventing the transmission of filarial, dengue, and malaria vectors.

Cis-3-Indoleacrylic Acid: A Nematicidal Compound from Streptomyces youssoufiensis YMF3.862 as V-ATPase Inhibitor on Meloidogyne incognita.

The application of the bionematicides derived from microorganisms and their secondary metabolites represents a promising strategy for managing root-knot nematodes. In this study, a nematicidal compound, cis-3-indoleacrylic acid, was isolated from Streptomyces youssoufiensis YMF3.862. This compound caused Meloidogyne incognita juveniles to have swollen bodies with apparent cracks on the cuticle surface. The LC50 value of cis-3-indoleacrylic acid against juveniles was 16.31 μg/mL 24 h of post-treatment. Cis-3-indoleacrylic acid at 20 μg/mL significantly inhibited V-ATPase expression and remarkably decreased enzyme activity by 84.41%. As an inhibitor of V-ATPase, cis-3-indoleacrylic acid caused significant H+ accumulation in nematode bodies, resulting in lower intracellular pH values and higher extracellular pH values of M. incognita. Application of 50 μg/mL cis-3-indoleacrylic acid generated a 71.06% control efficiency against M. incognita on tomatoes. The combination results of this study indicated that cis-3-indoleacrylic acid can be developed as a natural nematicide for controlling M. incognita.

Comparison of sublethal effects of 3 acaricides on life table parameters of Tetranychus urticae Koch (Acari: Tetranychidae) and Polyphagotarsonemus latus Banks (Acari: Tarsonemidae).

To assess the effects of sublethal concentrations of 3 acaricides-Bifenazate, Etoxazole, and Azocyclotin-on the development and reproduction of Tetranychus urticae Koch (Acari: Tetranychidae) and Polyphagotarsonemus latus Banks. Our results indicated that the LC20 values of Bifenazate, Etoxazole, and Azocyclotin against T. urticae are 3.196, 25.249, and 32.387mg/L, and against P. latus to be 18.058, 4.641, and 13.755mg/L, respectively. Sublethal concentrations of these acaricides significantly impacted the development time, lifespan, and fecundity of both mite species. Among the acaricides, Azocyclotin significantly extended the immature developmental period of T. urticae and P. latus. All acaricides reduced the lifespan and fecundity of both species, with Etoxazole having the most substantial impact on the daily fecundity and reproductive of T. urticae. The intrinsic rates of natural increase (rm) for T. urticae exposed to Bifenazate, Etoxazole, and Azocyclotin were 0.17, -0.04, and 0.20, respectively. For P. latus, the rm values were 0.27, 0.23, and 0.25, respectively. These results suggest that under the exposure of sublethal acaricides, P. latus gained a competitive advantage in population competition. These findings underscore the importance of understanding the differential impacts of acaricides on various mite species to develop effective pest management strategies.

Unveiling the Larvicidal Potential of Golpar (Heracleum persicum Desf. ex Fisch.) Essential Oil and Its Main Constituents on Aedes and Anopheles Mosquito Vectors

Natural products are thoroughly studied as valuable alternatives to synthetic insecticides. Heracleum persicum Desf. ex Fisch. (Apiaceae), commonly known as Golpar, is an Iranian medicinal plant largely employed as a spice, which has previously revealed insecticidal potential. The chemical composition of H. persicum essential oil (EO) was investigated by GC-MS and was mainly dominated by hexyl butyrate (36.1%) and octyl acetate (23.7%). The EO and its main esters were tested on three mosquito species. Aedes aegypti (L.) larvae were the most sensitive to all tested products. Lethal concentrations (LC50) of 59.09, 53.59, and 47.05 ppm were recorded for the EO, hexyl butyrate, and octyl acetate, respectively. Aedes albopictus (Skuse) and Anopheles gambiae Giles demonstrated comparable sensitivity to the EO, with LC50 values of 102.97 and 97.91 ppm, respectively, whereas the isolated constituents appeared more active on An. gambiae (LC50 of hexyl butyrate and octyl acetate of 70.97 and 60.71 ppm, respectively) with respect to Ae. albopictus (LC50 of hexyl butyrate and octyl acetate of 85.40 and 91.38 ppm, respectively). Low toxicity was registered for both EO and single components against human embryonic kidney (HEK293) cells. Overall, the H. persicum EO, hexyl butyrate, and octyl acetate could be further considered for larvicide development.

Hematobiochemical Changes, Immunological Response and Immune Gene Expression in Nile Tilapia (Oreochrom niloticus) Experimentally Infected with Shewanella putrefaciens

Background: In this work, hematobiochemical changes, immunological responses, and histopathological changes in Nile tilapia (Oreochromis niloticus) experimentally infected with Shewanella putrefaciens were studied. Methods: O. niloticus was experimentally infected with S. putrefaciens (4SK/SRLFDA/19) at a concentration of 1.508×106CFU/ml per fish. Gross symptoms, namely hemorrhage on the body surface, skin discoloration, slow or nervous behavior, shallow necrotizing ulcers on the skin, fin erosions and abdominal distension were observed 5 to 6 days after infection. Fish were anesthetized and blood samples were collected at 0, 2, 4, 7, 10, 14, 20 and 27 days after the experimental infection to assess the hematobiochemical and immunological responses. For haematobiochemical responses, tests that included hemoglobin (Hb), leukocyte count (Lc), erythrocyte, hematocrite (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), cholesterol (CHO), glucose (GLU) and triglyceride were assessed. Result: Values of hematocrit, hemoglobin, albumin, globulin, erythrocyte, MCHC, cholesterol and triglyceride were significantly (p less than 0.05) decreased. Lc, MCV, MCH, and glucose values were significantly (p less than 0.05) increased. Respiratory burst activity (RBA) and serum total protein values were significantly (p less than 0.05) decreased. Relative expression of immune gene toll like receptor 4 (TLR4), stress genes heat shock proteins 70, 90 (HSP70, HSP90), oxidative stress gene glutathione S-transferases (GST) and inflammatory gene interleukin 6 (IL6) was significantly higher in experimentally infected fishes compared to control.

Toxicity and Repellency of (E/Z)-3-Butylidenephthalide: A Natural Compound Isolated from Ligusticum porteri Root Extract Evaluated Against Imported Fire Ants (Hymenoptera: Formicidae)

Imported fire ants are pests of significant importance, especially in the southern United States. We tested (E/Z)-3-butylidenephthalide, a natural compound that was isolated from the ethanolic extract of Ligusticum porteri roots, as a repellent and toxicant against workers of imported fire ants. A series of serial concentrations, starting from 156 µg/g until failure, were tested using digging bioassays. Workers removed significantly less sand from the vials treated with (E/Z)-3-butylidenephthalide as compared to the ethanol control. Based on sand removal data, (E/Z)-3-butylidenephthalide treatment resulted in a more significant digging suppression against red imported fire ant workers at concentrations ranging between 19.5 and 0.6 µg/g than the solvent control whereas sand removal at 0.3 µg/g was similar with the solvent control. Black imported fire ants showed repellency at serial concentrations ranging between 19.5 and 0.15 µg/g whereas the hybrid imported fire ants showed repellency between 19.5 and 4.9 µg/g. In DEET treatments, red and black imported fire ants showed repellency at dosages of 125 to 62.5 µg/g, whereas the treatment failed at the dose of 15.6 µg/g in hybrid fire ants. (E/Z)-3-butylidenephthalide with LC50 values of 11 and 16.4 µg/g was toxic against red and black imported fire ants, respectively, followed by hybrid imported fire ants (LC50 = 104.7 µg/g). Fipronil with LC50 values of 0.49, 0.33, and 0.53 µg/g against red, black, and hybrid fire ants, respectively, was more toxic than (E/Z)-3-butylidenephthalide. In residual bioassay, toxic activity lasted for 3 weeks at dosages of 250 and 500 μg/g against HIFA. In residual bioassay, toxic activity lasted for 3 weeks at dosages of 250 and 500 μg/g against HIFA. The high repellency and toxicity of (E/Z)-3-butylidenephthalide against imported fire ants makes it a natural compound of interest for further evaluation under natural field conditions.

Biological Control of Aedes aegypti Larvae using Sea Shell Powder

Background: The Aedes aegypti mosquito is a primary vector for several arboviral diseases, including dengue, Zika, chikungunya and yellow fever, posing significant public health challenges, especially in tropical and subtropical regions. Traditional chemical insecticides have been the mainstay for controlling Aedes aegypti populations, but their extensive use has led to the development of insecticide resistance, environmental pollution and adverse effects on non-target organisms. This study explores the potential of sea shell powder as a natural larvicide against Aedes aegypti larvae. Methods: Sea shell powder, derived from the calcified exoskeletons of marine mollusks, was tested for its larvicidal activity against fourth instar larvae of Ae. aegypti at concentrations ranging from 100 to 600 ppm. Result: The results demonstrated a concentration and time-dependent increase in larval mortality, with LC50 values of 407.01 ppm at 24 hours and 327.55 ppm at 48 hours. The findings suggest that sea shell powder could serve as an effective, environmentally sustainable alternative to chemical insecticides, offering advantages such as biodegradability, low cost and reduced risk of resistance development. This study supports the potential inclusion of sea shell powder in integrated mosquito management programs, particularly in areas with prevalent insecticide resistance.

Validation of ethnopharmacological findings of Aegle marmelos (L.) Correa through phytochemical screening and bioactivity assay

For centuries, medicinal plants have been integral to human health and well-being across the world. Aegle marmelos (Rutaceae), a medicinal plant indigenous to Nepal, holds substantial ethnomedicinal use among indigenous communities in South Asian countries. Present study aimed to explore the integration of contemporary scientific analysis of the phytochemical composition and bioactivity of A. marmelos leaf extracts harvested from Nepal with traditional ethnopharmacological knowledge. Leaf extracts of A. marmelos were subjected to phytochemical analysis utilizing mass spectrometry. The extracts underwent in vitro evaluation for antimicrobial, antidiabetic, antioxidant, and toxicity activities. Hexane fraction was found to possess volatile oils, polyphenols, and tannins, while other fractions were found to have alkaloids, terpenoids, coumarins, flavonoids, glycosides, saponins, and reducing sugars. Further analysis of the hexane fraction identified 21 compounds with over 90 % accuracy. The main phytoconstituents were 9,12,15-octadecatrienoic acid methyl ester (24.25 %), hexadecanoic acid (10.89 %), methylcyclohexane (8.39 %), methyl ester (4.26 %), and caryophyllene (4.10 %). The methanol extract exhibited significant antibacterial activity against Staphylococcus aureus and Escherichia coli. Additionally, the methanol extract demonstrated pronounced cytotoxic effects against brine shrimp, with an LC50 value of 50.11 µg/mL. The 1,1-diphenyl-2-picryl hydrazyl assay revealed both methanol and acetone extract to have notable antioxidant activity, with IC50 values of 90.63 ± 1.47 µg/mL and 89.93 ± 2.52 µg/mL, respectively. Remarkably, the acetone extract displayed superior antidiabetic activity compared to acarbose, with an IC50 value of 13.50 ± 0.79 µg/mL. Our findings proves A. marmelos leaf extracts to harbor significant bioactive constituents, suggesting their potential as sources of natural compounds for applications in medicine and healthcare.

Acute and multigenerational effects of short-chain chlorinated paraffins on the harpacticoid copepod Tigriopus japonicus

Although the measurement of short-chain chlorinated paraffins (SCCPs) in aquatic ecosystems has increased, limited information is available on their toxic effects on aquatic animals. To evaluate the harmful effects of SCCPs, we assessed their acute impact on 24-h survival and biochemical parameters, as well as their chronic effects on growth and reproduction over three generations in the harpacticoid copepod Tigriopus japonicus. Dose-dependent increases in mortality were observed, with an LC50 value of 74.6 μg L−1 for 24 h. Acute exposure to the LC10 value for 24 h significantly reduced feeding behavior, accompanied by a notable decrease in acetylcholinesterase enzymatic activity. Simultaneously, the intracellular levels of reactive oxygen species increased, along with elevated malondialdehyde contents. Glutathione level was increased by the LC10 value of SCCPs with the induction of enzymatic activities of antioxidant defense components, including glutathione S-transferase, catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. When T. japonicus was continuously exposed to 1/10 of the NOEC and NOEC values for 12 days across three generations (F0–F2), growth retardation was observed in the F2 generation, with delay in the developmental periods from nauplius to adult. Although the total number of nauplii per brood was not significantly altered across generations, a significant delay in the onset of reproduction was observed in the F2 generation. Our findings suggest that even sublethal concentrations of SCCPs can negatively affect the health of copepod populations with consistent exposure.

Evaluation of the effects of two commercial pesticides on Daphnia magna in different feeding environments using morphological and biochemical markers

ABSTRACT In this study, the impact of exposure to a glyphosate-based herbicide (GBH) and a trifloxystrobin-based fungicide (TBF) on Daphnia magna in diverse feeding environments was assessed through the analysis of morphological and biochemical markers. The test organisms selected for analysis were Chlorella vulgaris and D. magna. First, the 48-hour median lethal concentrations (LC50) of GBH and TBF for D. magna were determined to be 253.1 mg/L and 20.7 µg/L, respectively. Secondly, the lethality, length, width, and spin length of D. magna were evaluated following exposure to sublethal pesticide concentrations, selected based on the LC50 values, in different feeding environments. Thirdly, the activities of glutathione S-transferase (GST), glutathione reductase, catalase (CAT), carboxylesterase, and acetylcholinesterase, as well as the levels of reduced glutathione, were measured in D. magna exposed to sublethal pesticide concentrations in different feeding environments. Both pesticides caused an increase in CAT activity, while GBH also caused an increase in GST activity in the unfed and mixed-fed groups. Conversely, it can be concluded that feeding with C. vulgaris reduces oxidative stress and toxic effects since there was a lesser increase in GST and CAT activities in the C. vulgaris-fed group for both pesticides, similar to the lethality.

Whole-Genome Sequencing of the Entomopathogenic Fungus Fusarium solani KMZW-1 and Its Efficacy Against Bactrocera dorsalis.

Fusarium solani KMZW-1 is recognized for its potential as a biocontrol agent against agricultural and forestry pests, particularly due to its compatibility with integrated pest management (IPM) strategies. This study aimed to investigate the complete genome of F. solani KMZW-1 and assess its pathogenicity against Bactrocera dorsalis. Whole-genome sequencing revealed a genome size of 47,239,278 bp, comprising 27 contigs, with a GC content of 51.16% and fungus identified as F. solani KMZW-1. The genome completeness was assessed as 97.93% using BUSCO analysis, the DFVF sequence identifier was Fusarium 0G092560.1, and AntiSMASH analysis identified 35 gene clusters associated with secondary metabolite biosynthesis, providing insights into the genetic basis of its pathogenic mechanisms and biocontrol potential. Comparative genomic analysis found 269 unique genes for F. solani KMZW-1, and collinearity analysis exhibited a high degree of synteny with Fusarium solani-melongenae. The pathogenicity of F. solani KMZW-1 was assessed using concentrations ranging from 1 × 104 to 1 × 1011 conidia/mL. Higher concentrations (1 × 1010 to 1 × 1011 conidia/mL) resulted in significantly increased cumulative mortality rates of B. dorsalis adults compared to the control group. Notably, the pathogenicity was higher in male adults than in females. Probit analysis yielded LC50 (50% lethal concentration) values of 5.662 for female and 4.486 for male B. dorsalis adults. In summary, F. solani, KMZW-1 exhibits strong insecticidal activity against B. dorsalis and shows potential as a biocontrol agent with IPM strategies. These findings provide robust genomic evidence supporting the use of F. solani KMZW-1 in managing against B. dorsalis populations.

Chemical characterization, antimicrobial and mosquito larvicidal activities of the essential oil of Camellia pleurocarpa (Gagnep.) Sealy from Vietnam

Camellia pleurocarpa (Gagnep.) Sealy, a species of yellow camellia indigenous to Vietnam, was investigated for its essential oil properties in this study. Hydrodistillation of its leaves yielded a complex mixture rich in sesquiterpenes and diterpenes. Chemical analysis identified 50 constituents, with notable compounds including spathulenol (13.26%), phytol (9.94%), and α-selinene (5.34%). The essential oil exhibited significant antimicrobial activity against three Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus; one Gram-negative bacterium Pseudomonas aeruginosa; and one yeast Candida albicans, with minimum inhibitory concentration (MIC) values ranging from 16 to 32 μg/mL and half-maximal inhibitory concentration (IC50) values ranging from 7.26 to 16.23 μg/mL. Furthermore, it demonstrated larvicidal potential against Aedes aegypti and Culex quinquefasciatus mosquitoes, with LC50 values ranging from 13.49 to 28.95 μg/mL and LC90 values ranging from 28.29 to 53.24 μg/mL. These findings underscore the promising antimicrobial and mosquito larvicidal properties of C. pleurocarpa essential oil, suggesting its potential as a natural alternative in combating microbial infections and controlling mosquito-borne diseases. This study represents the first comprehensive report on the chemical compositions and bioactivities of C. pleurocarpa essential oil.

Tri-iso-butyl phosphate (TiBP) exposure induces neurotoxicity by triggering oxidative stress accompanied by neurotransmitter system disruptions and apoptosis in zebrafish larvae

The current research sheds light on the biological toxicity of organophosphate flame retardants (OPFRs), yet it overlooks the neurotoxicity and potential molecular mechanisms of tris(1,3-dichloro-2-propyl) phosphate (TiBP), a prominent constituent of the OPFRs. To address this, we utilized zebrafish larvae as a model to investigate TiBP's acute toxicity and neurotoxic effects, along with the associated molecular pathways. Our findings revealed that the 96 h and 120 h LC50 values for TiBP were 56.51 mg/L and 48.85 mg/L, respectively. Gradient exposure based on the 120 h LC50 demonstrated that TiBP induced developmental toxicity, characterized by elevated heart rate, reduced body length, and diminished eye distance. Additionally, a decrease in swimming activity was observed in the light test, along with the inhibition of the neuro crest cell development in Tg (HuC:eGFP) and Tg (sox10: eGFP) zebrafish larvae following TiBP exposure, as well as the alterations of neurogenesis and ACh-related genes. Expression of key neurodevelopment genes, including mbpa, gap43, nestin, ngfra, was significantly downregulated. Furthermore, heightened anxiety-like behaviors in open field and phototaxis tests were observed, concomitant with neurotransmitter imbalances. Specifically, there was an increase in DA levels, a decrease in GABA, and an upregulation of AChE activity. These disruptions were primarily mediated through transcriptional dysregulation of neurotransmitter synthesis, transport, and reception. Upon exposure to TiBP, zebrafish larvae exhibited a concentration-dependent increase in both ROS level and apoptosis. An upregulation of antioxidant enzymes and their transcription levels indicated the presence of oxidative stress in the larvae. The induction of ddit3 was congruent with the observed apoptosis, suggesting that it may be triggered by oxidative stress via the ERs-CHOP pathway. In summary, our study indicates that oxidative stress is a pivotal molecular event in the neurotoxicity induced by TiBP, implicating the disruption of the GABAergic, dopaminergic, and cholinergic systems, as well as triggering apoptosis.

Sulcatone as a Plant-Derived Volatile Organic Compound for the Control of the Maize Weevil and Its Associated Phytopathogenic Fungi in Stored Maize.

Stored maize is frequently attacked by different pests, such as insects and microorganisms. The aim of the present study was to evaluate the bioactivities of sulcatone (6-methyl-5-hepten-2-one) against the maize weevil Sitophilus zeamais and the phytopathogenic fungi Fusarium verticillioides, Aspergillus flavus, and A. parasiticus. Sulcatone showed a strong repellent effect with a maximum value of -92.1 ± 3.2% at 40 µM in two-choice olfactometer bioassays and an LC95 value of 17.2 µL/L air (95% 16.5-18.1) in a fumigant toxicity experiment. The antifungal effect of sulcatone was evaluated through the fumigant method, reporting MIC values of 3.5, 3.8, and 3.9 mM for F. verticillioides, A. parasiticus, and A. flavus, respectively. Additionally, a silo-bag experiment containing all pests was conducted to evaluate the potential use of sulcatone in a real storage system. Sulcatone caused 71.69 ± 1.57% weevil mortality in silo-bags and proved to be effective as a fungicidal and antimycotoxigenic agent since both ergosterol and fumonisin B1 content were significantly reduced by 60% in silo-bags containing sulcatone. This study demonstrated that sulcatone has the potential to be used for the control of both insects and fungi of stored maize, without affecting the germination of grains.

Investigation of the effect of water and feed sourced boron on the growth performance and blood parameters of Nile tilapia, Oreochromis niloticus

AbstractThis study investigated the effects of water and feed‐derived boron on the growth performance and blood parameters of Nile tilapia fingerlings. Two different experiments were designed for this purpose. The first phase of the study determined the LC50 (96‐h) value of boron for Nile tilapia. Fish were then fed in water containing boron at a ratio of 1:20 of the LC50 value. In the second experiment, feed containing boron at different rates (0.00%, 0.01%, 0.05%, and 0.10%) was fed for 40 days. At the end of the feeding period, growth performance, hematology, and blood biochemistry parameters were determined. The study concluded with a calculated LC50 value of 161.053 mg/L boron for Nile tilapia. The initial weight was 12.51 ± 0.79 g; at the end of feeding, the final weights were determined as 26.36 ± 0.15 g for the control and 28.07 ± 0.23, 32.28 ± 0.25 and 24.81 ± 0.48 g for 0.01%, 0.05% and 0.10% of boron feed treatments, respectively. At the end of feeding in water containing boron, the final weight of Nile tilapia was determined as 24.26 ± 0.26 g (LC50/20%). The results showed that feeding Nile tilapia with 0.05% boron‐supplemented feed stimulated growth and positively affected blood parameters, whereas waterborne boron inhibited Nile tilapia growth and negatively affected blood parameters.