LC50 Concentration Research Articles

Biodegradability and ecotoxicity of bio-insulating oils in aqueous and soil environments in Douala, Cameroon

This work focuses on the analysis of the deleterious effects in case of spills in aqueous and soil environments of palm kernel oil methyl esters (PKOME) and castor oil methyl esters (COME) prototyped to substitute mineral oils in power transformers. Two main properties were investigated according to the Organization for Economic Cooperation and Development (OECD) standards. Biodegradability based on the OECD-301B guideline for CO2 release in biological media; and acute toxicity, analysed according to the OECD-203 guidelines for fish and OECD-207 guidelines on earthworms. At the end of 28 days of incubation, the PKOME samples showed a biodegradation rate of 92.6% in Wouri water and 74.93% in Douala soil. COME samples showed a biodegradation rate of 67.4% in aqueous medium and 57.64% in soil medium. Whatever the biological medium, the degradation rates of the PKOME prototypes were better than that of COME, and both were higher than those of mineral oils. The acute toxicity test was carried out on Arius africanus fish in an aqueous medium and earthworms type Eisenia foetida in soil medium at different doses of the substances. In both bioindicators, spills from the COME prototypes showed a moderate toxic effect. In aqueous medium, they caused 50% mortality at an LC50 concentration of 1.35 gl−1 and LC100 of 2.66 gl−1. In soil, the LC50 obtained were 1958.4 ppm (PKOME) and 541.73 ppm (COME).

Larvicidal Potential of Essential Oils Extracted from Syzygium aromaticum Against Aedes albopictus In Malaysia: A Preliminary Study

Introduction: The use of chemical insecticides has raised concerns regarding its consequences on human health and as well as its detrimental environmental impacts. Essential oils obtained from botanical origins can be used as natural alternatives to circumvent these concerns. As such, the purpose of this study is to evaluate the larvicidal efficacy of essential oil extracted from Syzygium aromaticum against Aedes albopictus. Methods: Larvae sampled were reared and maintained under insectary conditions following standard protocols. The essential oil from Syzygium aromaticum was extracted by hydrodistillation and tested against Aedes albopictus larvae for its susceptibility and lethality at 24 and 48 hours. The LC50 and LC90 lethal concentration values were determined using Probit regression analysis. Results: Syzygium aromaticum essential oil revealed larvicidal actions against Aedes albopictus species which was concentration-dependent, causing 100% larval mortality at 300 ppm. LC50 and LC90 were observed at 239.5 ppm and 275.3 ppm following 24-hour exposure, and 235.5 ppm and 277.8 ppm after 48 hours respectively. Conclusion: The findings from this study highlight the conceivable use of essential oils extracted from Syzygium aromaticum as potential sources for the development of a larvicidal agent. The findings could be used to catalyse further efforts to develop alternative strategies to control Aedes albopictus.

Sublethal effects of oregano essential oil and its major compound carvacrol on biological parameters of Aedes albopictus (Diptera: Culicidae)

Mosquito management programs rely basically on the use of conventional synthetic larvicides. However, frequent applications and misuse of some synthetic insecticides have led to problems related to mosquito resistance development, harmful effects on human health and unacceptable environmental effects on non-target organisms. Recently, a growing number of phytochemicals has been tested as more eco-friendly larvicides against various mosquito species, exerting high efficacy with multiple modes of action. In the laboratory, we investigated for the first time the sublethal effects of oregano oil and its major compound carvacrol, against Aedes albopictus (Asian tiger mosquito), a mosquito of great medical importance. We determined the effects of short term (24h) exposure of 3rd- 4th larvae to LC50 concentrations on survival and development of survived larvae until adulthood, as well as on fecundity, fertility, longevity and wing length of emerged adults. Only half of 24h survived larvae from oregano oil and carvacrol treatment finally reached adulthood. Abnormal shapes of dead larvae and pupae, and failed adult emergence were also observed, indicating a potential growth inhibitory activity of the tested materials. No particular effects from exposure to larvicidal LC50 concentrations were recorded on life cycle parameters of successfully emerged adults. These findings suggest the tested oregano oil and carvacrol as sufficiently effective larvicides against Ae. albopictus at lower than the acutely toxic concentrations, promoting a more eco-friendly and less costly profile for these biopesticides.

The Effect of LL37 Antimicrobial Peptide on FOXE1 and lncRNA PTCSC 2 Genes Expression in Colorectal Cancer (CRC) and Normal Cells.

As an innate immune system component, antimicrobial peptides (AMPs) exert various effects, such as anticancer properties. This study aimed to evaluate the LL37 AMP anticancer effect against colorectal cancer (CRC) cells and the expression of FOXE1 and lncRNA PTCSC2 genes. The LL37 AMP was purchased from GenScript USA, Inc. Various CRC cell lines (HCT-116, HT29, WiDr, and SW742) were cultured in the DMEM medium. Various concentrations ranging from (5-400) μg/mL of LL37 AMP were prepared, added to cell cultures, and incubated for (24 and 48) hours. A nontoxic level of 30 µg/mL of LL37 was investigated for FOXE1 and lncRNA PTCSC2 gene expression. At 24 hours, the (50 and 90) % lethal concentrations of LC50 and LC90, respectively, of LL37 against NCM460 normal cells were (640 and > 640) g/mL. Additionally, these values at 48 hours included (160 and > 640) µg/mL, respectively. After 24 hours of treatment, the LC50 and LC90 of LL37 AMP against CRC cell lines included (20 and 200) µg/mL. The LC50 and LC90 of the LL37 at 48 hours included (20 and 50) µg/mL and at 72 hours. they included (~10 and 40) μg/mL, respectively. FOXE1 but not the PTCSC 2 gene expression was significantly higher in CRC cells than normal cells (NCM460 and HaCaT). The LL37 AMP significantly decreased FOXE1 gene expression by 1.95-fold in CRC cells (p < 0.001). The FOXE1 gene can be considered a biomarker of CRC development. The expression of FOXE1 but not the PTCSC2 gene was significantly affected by the LL37 AMP. The effects of LL37 AMP against CRC cells were time and dose-dependent. Future studies are warranted to verify these effects.

Waterborne copper sulfate toxicity in Nile tilapia (Oreochromis niloticus) juveniles affect survival, growth, and physiology

ABSTRACT This study aimed to evaluate the acute and long-term exposure to different cupric sulfate pentahydrate (CuSO4.5H2O) concentrations in Nile tilapia (Oreochromis niloticus). Experiment 1 evaluated the LC50-96 h of juveniles at 12 different CuSO4.5H2O concentrations (0.00, 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, 12.8, 25.6, 51.2, 102.4, and 204.8 mg L–1). In experiment 2, fish were exposed to four different sublethal cupric sulfate pentahydrate concentrations (0.0, 0.0069, 0.0696, and 0.6960 mg L–1) with evaluations on days 20 and 40. In the first experiment, the LC50 and safe concentration for 96 h were, respectively, 6.96 and 0.6960 mg CuSO4.5H2O L−1. In the second experiment, fish subjected to 0.6960 mg CuSO4.5H2O L–1 decreased growth performance and survival, altered hematological parameters, and had hepatic vacuolation and liver necrosis. In conclusion, we have found that to control the excessive algae growth, fish could tolerate a concentration of up to 0.0696 mg CuSO4.5H2O L−1 for 40 days.

The genotoxic, cytotoxic and growth regulatory effects of plant secondary metabolite β-caryophyllene on polyphagous pest Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

Use of secondary metabolites as an alternative to organic pesticides is an eco-friendly and safe strategy in pest management. β-caryophyllene [(1R,4E,9S)-4,11,11-trimethyl-8-methylene bicyclo [7.2.0]undec-4-ene], a natural sesquiterpene is found as an essential oil in many plants like Syzygium aromaticum, Piper nigrum, Cannabis sativa. The present study aims at exploring the insecticidal, genotoxic and cytotoxic potential of β-caryophyllene against common cutworm Spodoptera litura (Fab.), a major polyphagous pest. S. litura larvae were fed on different concentrations (5, 25, 125, 625 and 3125 ppm) of β-caryophyllene. Results revealed delay in larval and pupal period with increase in concentration. Larval mortality increased and adult emergence declined significantly with increase in concentration. Higher concentrations of β-caryophyllene caused pupal and adult deformities. A negative impact of β-caryophyllene was also seen on the nutritional physiology of S. litura. Parameters such as relative growth rate, relative consumption rate, efficiency of conversion of ingested food, efficiency of conversion of digested food and approximate digestibility showed a significant reduction in a dose dependent manner. DNA damage assessed using comet assay revealed significant genotoxic effects at LC30 and LC50 concentrations. There was an increase in tail length, percent tail DNA, tail moment and olive tail moment. Phenol oxidase activity was suppressed at LC50 concentration with respect to control. Total hemocyte count also declined significantly at LC30 and LC50 concentrations as compared to control. β-caryophyllene induced genotoxic and cytotoxic damage affecting the growth and survival of S. litura larvae. Our findings suggest that β-caryophyllene has the potential to be used for the management of insect pests.

Overcoming Drug Resistance in Breast Cancer Using Quercetin Nanodrugs

Background &amp; Objective: Breast cancer is one of the most common cancers in the world. Treatment methods for this disease have been with poor results. In recent years, more attention has been paid to stem cells due to their cytotoxic properties. According to previous results, the effect of nanoquercetin on breast cancer cells in this study was used concomitantly with doxorubicin, which is a chemotherapy drug and in some patients has therapeutic resistance.&#x0D; Materials &amp; Methods: The above study was performed on MCF7 and BT474 human breast cancer cells. Quercetin was synthesized, then different concentrations of 10, 20, 40, 80 and 160 of quercetin and 1, 2.5, 5 and 10 μg/ml of doxorubicin were prepared and two cell lines were treated for 24 h. MTT test was used to determine cell viability and flow cytometry test was used to determine the extent of apoptosis in both cell lines.&#x0D; Results: The results showed that MCF7 and BT474 cells that were affected by quercetin and doxorubicin, increasing the concentration of quercetin and doxorubicin decreased the survival of both cell lines within 24 h. The LC50 concentration was calculated for both cells treated with nanoquercetin 40 μg/ml and for doxorubicin (0.1 mg/mL). The results also showed that in both cell lines, an increase in cellular apoptosis occurred after incubation with quercetin and then incubation with doxorubicin.&#x0D; Conclusion: Comparison of doxorubicin (DOX), quercetin (QU) and quercetin and doxorubicin (QU-DOX) groups with controls shows that with the presence of quercetin-doxorubicin, it had a greater inhibitory effect on cancer cells.

Insecticidal Potentials and Identification of Bioactive Compounds from Extracts of Bacopa Floribunda and Ludwigia Decurrens Plants

The negative impact of insecticides used to combat insect-borne plant ailments cannot be emphasized, as they have had a major influence on plant yields throughout time, and the side effect of insecticide residue on consumers cannot be overstated either. Callosobrochus maculatus is an insect that attacks cowpeas and has the potential to significantly reduce crop productivity. This research developed from investigations into the utilization of biological control technologies that have little or no harmful influence on humans or the environment. The leaves of Bacopa Floribunda (BFL) and Ludwigia Decurrens (LDL) were air dried, powdered, and extracted with n-hexane. The insecticidal activities were carried out according to protocol, and the LC50 was determined using online software from AAT Bioquest, Inc. The presence of bioactive compounds was detected using GC-MS. The Callosobrochus maculatus mortality rate was found to be a function of exposure time and concentration of the extracts, with the maximum mortality rate (66.67±8.82 percent) occurring after 72 hours at 0.5 mg/ml for BFL extract. The highest mortality rate (70.00 ±5.77 percent) was obtained for the LDL extract at 72 hours at 0.5 mg/ml of the extract concentration, which was better than the other extract (BFL) at 0.5 mg/ml. The lethal concentration LC50 for BFL varies from 0.251 (24 hours), 0.276 (48 hours), and 0.223 (72 hours), while the LC50 for LDL extract is 0.228 (24 hours), 0.039 (48 hours), and 0.663 (72 hours) (72 hrs). The presence of chemicals found could be linked to the extracts’ insecticidal properties. The excellent potential of the extracts as insect biocontrol agents against Callosobrochus maculatus can be recommended for future research as insect biocontrol agents.

Bromuconazole exposure induces cardiotoxicity and lipid transport disorder in larval zebrafish

Bromuconazole (BRO), as one of the typical triazole fungicides, has not been reported on its effects on aquatic organisms. In this study, zebrafish embryos were used as experimental objects to evaluate the toxicity of BRO. In the acute embryo toxicity test, it was observed that the heart rate and growing development were affected by BRO in a concentration-dependent manner, and the half-lethal concentration (LC50) of BRO at 96 h post-fertilization (hpf) was about 11.83 mg/L. Then, low concentrations of BRO (50 ng/L, 0.075 mg/L, 0.3 mg/L, 1.2 mg/L), which were set according to the LC50 and environmental related concentrations, were used to analyze the toxic effects on the different endpoints in larval zebrafish. Interestingly, the transcriptomic analysis found that most different expressed genes (DEGs) could be focused on the pathways of lipid metabolism, myocardial function, glycometabolism, indicating that heart function and lipid metabolism in larval zebrafish were disrupted by BRO. For supporting this idea, we re-exposed the transgenic zebrafish and WT zebrafish embryos, proved that BRO caused damage to heart development and lipid transport on morphological and genetic level, which was consistent with transcriptomic results. In addition, BRO exposure caused oxidative damage in the larvae. Taken together, BRO exposure could affect the myocardial contraction function and lipid transport in larval zebrafish, accompanied by disturbances in the level of oxidative stress, which was of great significance for improving the biotoxicological information of BRO.

Neurospecific fabrication and toxicity assessment of a PNIPAM nanogel encapsulated with trans-tephrostachin for blood-brain-barrier permeability in zebrafish model

Biocompatible Poly(N-isopropylacrylamide) (PNIPAM) nanogels (NGs) were developed at 40–65 nm to deliver Trans-Tephrostachin (TT) in zebrafish brain. Neurospecific PNIPAM NGs are functionalized with polysorbate 80 (PS80) to overcome the Blood Brain Barrier (BBB). The TT loaded with NG (NG + TT) was confirmed in UV-spectroscopy and transmission electron microscopy (TEM) with 90% efficiency of controlled release at 37 °C. The neurospecificity of NG was confirmed in 144 hours post fertilization (hpf) larvae with PS80 surface-treated rhodamine-B (Rh–B) conjugated NG and visualized in the zebrafish CNS. Oral gavaging of TT loaded NG with PS80 surface treatment (NG + TT + PS80) was confirmed to cross the BBB in adult zebrafish at 37 °C. TT release was detected by RP-HPLC. LC50 was determined as 250 μg/ml for NG, 172 μg/ml for NG + TT, and 0.9 μg/ml for TT at 96 hpf and confirmed the lesser toxicity in TT bound NG. Delays in growth and malformations were observed at concentrations above the 96 hpf-LC50. The behavior outcomes were varied with phase - and concentration-dependent hypo- or hyperactivity. The altered expression of genes associated with Alzheimer’s disease (AD) was found at 96 hpf of its LC50 concentration. The expression of appa was significantly increased for TT and supporting the TT to bind NG without altering the AD genes. Thus the study suggests the biocompatible potential of PNIPAM and its neurospecific delivery to the brain.

Insecticidal and P450 mediate metabolism of fluralaner against red imported fire ant, Solenopsis invicta (Hymenoptera: Formicidae)

The red imported fire ant (Solenopsis invicta), a worldwide invasive and polyphagous pest, and often nests in residential areas. Finding an alternative pesticide that is both effective on S. invicta and environmentally friendly is urgent and crucial. Fluralaner, a novel isoxazoline insecticide, has been proven to possess selective toxicity for insects versus mammals and has been safe for mammals and non-target organisms, suggesting its potential in pest management. However, little toxicity information is available for the controlment of S. invicta. In this article, we studied the toxicity of fluralaner against S. invicta systematically, and the roles of metabolism-related enzymes in the metabolism process of fluralaner. The toxicity results showed that the topical application and feeding application were all effective for S. invicta. Moreover, fluralaner can be transmitted among workers by contacting and feeding which leads to a toxic reaction among nestmates. By exploring the biochemistry change, we found cytochrome P450 monooxygenase (P450) may be involved in the detoxification of fluralaner as well as carboxylesterase (CarE), but not glutathione S-transferase (GST). Synergism assays gave solid evidence in which piperonyl butoxide, an activity inhibitor of P450, increased the toxicity of fluralaner to S. invicta. Importantly, with the RNAi treatment, four of S.invicta P450 genes were significantly inhibited and showed more sensitivity to fluralaner at LC50 concentration. Our result indicated that fluralaner could be a potential alternative pesticide in S. invicta control. And CYP9AS16, CYP6AS161, CYP6SQ20, and CYP336A45 genes were closely associated with the metabolism process of fluralaner.

Efficiency of Ocimum basilicum and Eucalyptus globulus essential oils on anesthesia and histopathology of rainbow trout, Oncorhynchus mykiss

AbstractIn this study, anesthetic effects of Ocimum basilicum and Eucalyptus globulus essential oils were investigated on rainbow trout, Oncorhynchus mykiss. Fish (average 10 g) were exposed to 20, 50, 70, 100, 150, 200, 300, 400, 500, and 600 mg L−1 essential oils, anesthesia induction, and recovery times were recorded separately for each fish. Acute toxicities of essential oils (10 min LC50 concentration) on rainbow trout were determined at 70–400 mg L−1. In addition, histopathological effects of the essential oils in fish tissues were determined after deep anesthesia. As a result of this study, O. basilicum at 300 mg L−1 dose and E. globulus essential oils at 400 mg L−1 dose showed ideal anesthetic effects on rainbow trout. Anesthesia induction (stage 4) and recovery times at this concentration for E. globulus were found as 186 and 117.5 s, respectively. Anesthesia induction (stage 4) and recovery times were 220.5 and 61 s for this concentration in O. basilicum essential oil, respectively. The toxic effects of essential oils for rainbow trout were not found. No pathological finding in gill, liver, and kidney was observed at the histopathological examination. Consequently, this study demonstrated that O. basilicum and E. globulus essential oils can be used as an effective and safe anesthetic in rainbow trout.

Toxicity of synthesized silver nanoparticles in a widespread fish: A comparison between green and chemical

Metallic nanoparticles are gaining importance in various fields of life due to their large surface area to volume ratio. However, metallic nanoparticles pose different toxic effects on fish when they appear with different shapes and compositions in water. Herein the present study was designed to evaluate the median (LC50) and sub-lethal (1/10th of LC50) concentrations of Ag-Green NPs, 700 μg/L for Ag-Chem NPs, and 50 μg/L for Ag2O-Chem NPs were confirmed in Hypophthalmichthys molitrix. Furthermore, exposure of H. molitrix fingerlings to 10 % of LC50 concentration of these particles induced significantly higher (p < 0.05) activities of serum alanine transaminase, aspartate aminotransferase, lactate dehydrogenase, white blood cells, acetylcholinesterase and catalase, superoxide dismutase, peroxidase, relative gene expressions of antioxidant enzymes, heat shock protein (Hsp70), hypoxia- inducible factor 1-alpha (HIF-1α) and lipid peroxidase level than the control, but decreased hematological parameters with less effects of Ag-Green NPs than chemically synthesized AgNPs. Moreover, the histopathological study also indicated morphological changes in the liver and gills of treated fish groups. The comparative toxicity evaluation revealed the maximum negative effect of Ag2O-Chem NPs followed by Ag-Chem NPs while Ag-Green NPs showed the least toxic effects. Based on our results, replacement of chemically synthesized NPs to green synthesized AgNPs can be recommended in large scale application to reduce the noxious effects to aquatic environment.

Toxicity and Sublethal Effects of Fluxametamide on the Key Biological Parameters and Life History Traits of Diamondback Moth Plutella xylostella (L.)

Fluxametamide, a novel isoxazoline insecticide, is newly registered for the control of various lepidopteran, coleopteran and thysanopteran insect pests on lethal and sublethal levels. In the present study, the toxicity and sublethal effects of fluxametamide on diamondback moth Plutella xylostella (L.), an invasive lepidopteran foliage feeder of cruciferous vegetables, were assessed to explore its bio-ecological impact on pest populations. The toxicity of fluxametamide to the third instar larvae of P. xylostella was 0.18 mg L−1 (LC50) at 72 h bioassay. After treatment with LC10 and LC30 concentrations of fluxametamide, the fourth instar larval duration, the rate of deformed pupa and adults, and the adult pre-oviposition period were significantly increased, whereas the pupation rate and pupal weight were significantly decreased in the F0 generation. In the F1 generation, sublethal effects of fluxametamide were indicated by a reduced fecundity, rate of pupation and adult emergence, pupal weight, and adult longevity, however a significant increase in eggs and total larval duration, deformed adults rate, and total longevity and pre-oviposition period was observed in the offspring. The intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0) of sublethal treatments were significantly lower than the control. The relative fitness of F1 was 0.68 and 0.64 in LC10 and LC30 treatments, respectively. The LC30 fluxametamide treatment exhibited increased glutathione S-transferase activities (elevated 1.433-fold) in P. xylostella. Our results suggest that in addition to its high lethal toxicity, the sublethal concentrations of fluxametamide might suppress the reproduction, development and survival of the P. xylostella population and its progeny, which can help to optimize integrated pest management program.

Overexpression of ATP-binding cassette transporters ABCG10, ABCH3 and ABCH4 in Aphis craccivora (Koch) facilitates its tolerance to imidacloprid

Aphis craccivora (Koch), a globally pest that causes significant threat to the legumes, has developed different degrees of resistance to a variety of insecticides. The ATP-binding cassette (ABC) transporters comprise a multifunctional transporter protein superfamily which play important roles in the transport and detoxification of xenobiotic compounds in insects. However, whether ABC transporters take part in the tolerance of imidacloprid in A. craccivora is still unknown. In order to investigate the functions of ABC transporters in the imidacloprid tolerance, fifty- eight ABC transporters were identified in the transcriptome and genome of A. craccivora and the toxicity of imidacloprid against A. craccivora was significantly increased after application the inhibitors of verapamil and Ko143. The relative expression levels of ABCG5, ABCG6, ABCG10, ABCH3, ABCH4, ABCH8 and ABCH10 were significantly up-regulated in response to imidacloprid treatment with LC15, LC50 and LC85 concentrations, and the expression patterns of these seven ABC transporters were further analyzed at different developmental stages and in different tissues of A. craccivora by quantitative real-time PCR (RT-qPCR). Furthermore, knockdown of ABCG10, ABCH3 and ABCH4 significantly increased the mortality of A. craccivora to imidacloprid. Our results reveal the key functions of ABC transporters in the tolerance of imidacloprid and provide valuable information regarding the development of improved management strategies in A. craccivora.

GC/MS Analysis of Eucalyptus globulus L. (Myrtaceae) Leaves Essential Oil from Algeria and their Insecticidal Activity Against Adults of Bactrocera oleae (Rossi) (Diptera; Tephritidae)

In this study, the essential oil of leaves Eucalyptus globulus (Myrtales: Myrtaceae) was analyzed by gas chromatography/mass spectrometry (GC/MS) and their potential insecticidal against the olive fruit fly Bactrocera oleae (Diptera: Thephritidae) was investigated. The essential oil yield was 0.36 ± 0.03% (w/w). A total of 41 compounds (99.99%) were identified. (-)-spathulenol (32.66%), o-cymene (28.30%) and (+-)-cryptone (12.13%) were major constituents. The toxic impact of essential oil of E. globulus was assessed against B. oleae adults through two toxicity tests (contact and fumigation). B. oleae was more susceptible to E. globulus and adult mortality increased according to concentration and exposure time. In the contact toxicity, the lethal concentration LC50 values were 0.24 µL/cm2 and 0.15 µL/cm2 in 24 h and 48 h, respectively and LC90 values of 0.64 µl/cm2 and 0.33 µL/cm2 were obtained in 24 h and 48 h, respectively. In fumigation assay on olive fruit fly adults, LC50 values were 14.05 μL/L air and 5.71 μL/L air at 24 h and 48 h, respectively and LC90 values of 51.53 μL/L air and 21.64 μL/L air at 24 h and 48 h, respectively. The findings of current study show that use of essential oil of leaves of E. globulus against B. oleae is considered as an eco-friendly alternative natural insecticide.

Er3+/Sm3+ co-doped Bi2O2CO3 in photocatalytic water treatment: Immobilization, acute toxicity, sterilization, and catalytic oxidation activity

Defect construction and rare earth doping are the linchpins to completing the target of partial electronic regulation. In Er3+/Sm3+ co-doping Bi2O2CO3, rare earth doping resulted in the exposure of {001} crystal plane in Bi2O2CO3 and cause surface defects and electron traps, achieving wide light response capability and fast carrier separation. Furthermore, a potential TC degradation route was acknowledged derived from LC-MS. Then, the median lethal concentration LC50 (96 h) is 80 ppm, probing the 2E2SBOC photocatalyst has low toxicity in actual wastewater. Combining with immobilization technology, not only does it have little impact on the organisms in the wastewater, but it is easy to recycle after degradation. In terms of new water disinfection technology, bacterial experiments in natural waters proved that 2E2SBOC has a potential disinfection system, which promotes the exposure of more active sites during degradation. This effective project offers a novel perspective for the development and application of rare-earth-doped photocatalysts.

TOXICOLOGICAL EFFECTS OF A BINARY MIXTURE OF METALS (Fe+Mn) ON THE OXIDATIVE STRESS OF MAJOR CARPS

Oxidative stress caused by various pollutants in water can be overcome by different mechanisms in aquatic organisms. Antioxidant enzymes play major role to minimize the hazardous effect of heavy metals in fish. Superoxide dismutase is one of the antioxidant enzyme that converts the superoxide radical into hydrogen peroxide (H2O2) and thus minimize the stress caused by free radicals. Therefore, the aim of this research was to evaluate the activity of superoxide dismutase (SOD) in the organs (liver, kidney, gills and muscles) of Catla catla and Cirrhina mrigala exposed to 1/3rd and 1/4th concentrations of 96-hr LC50 of Fe+Mn. These experiments were conducted in glass aquaria with three replications of each concentration for 1 month in controlled laboratory conditions. SOD activity was significantly increased in liver and gills of both fish species compared to control group. Maximum SOD activity in the Fe+Mn mixture exposed Catla catla was measured as 46.55±7.58 and 43.69±5.34 UmL-1 in the liver and gills, respectively, at 1/4th concentration of 96-hr LC50 while in control fish the activity of SOD was recorded as 33.36±6.72 and 34.16±3.19 UmL-1, respectively. Similarly, SOD activity increased with decrease in concentration in Cirrhina mrigala. Maximum activity of enzyme (52.30±7.33 UmL-1) in Cirrhina mrigala was observed in the liver at 1/4th concentration of 96-hr LC50 compared to control in which the activity of enzyme was recorded as 46.95±3.93 UmL-1. The SOD activity in all the metals mixture treated and un-treated fish groups were found lower in muscles than that of other organs.

Toxicity, antifeedant and physiological effects of trans-anethole against Hyphantria cunea Drury (Lep: Arctiidae)

Plant secondary metabolites are currently known to interfere with basic metabolic, behavioral and physiological processes of insects. In the current study, the biological and physiological effects of trans-anethole were investigated against Hyphantria cunea Drury. The bioassay data demonstrated the high toxicity of trans-anethole against the fourth-instar larvae with the LC30, LC50 and LC90 values of 0.72, 1.41 and 7.20 μL/mL, respectively. Also the concentrations of LC30 and LC50 showed 53 and 87% feeding deterrency against the larvae. The biochemical experiments revealed that oral exposure of trans-anethole decreased the activities of digestive enzymes, acetylcholinesterase and the contents of energy reserves while, it induced the activities of detoxifying and antioxidant enzymes compared to control. In fact, trans-anethole induced the inhibition of digestion and AChE activities accompanied by imbalance in metabolic and oxidative processes so it may be recommended as a potent biopesticide in control of H. cunea populations.

Sublethal Effects of Three Insecticides on Development and Reproduction of Spodoptera frugiperda (Lepidoptera: Noctuidae)

Spodoptera frugiperda is a serious invasive pest, which has attracted attention globally in recent years. Research on the sublethal effects of common insecticides on S. frugiperda is important for its comprehensive management in the field. In this paper, the sublethal effects have been studied for S. frugiperda exposed to the LC30 concentration of three insecticides, chlorantraniliprole, dinotefuran, and beta-cypermethrin. The results showed that the pupation rates of the treatment groups were significantly lower than that of control group, but there were no significant differences in the eclosion rate. Chlorantraniliprole and beta-cypermethrin significantly inhibited fecundity of the F0 and F1 generations, and the number of eggs laid per female decreased by 67.4% and 43.1%, respectively, and that of the F1 generation decreased by 28.0% and 21.7%, respectively. The intrinsic growth rate (rm), net growth rate (R0), and weekly growth rate (λ) of the F0 generation in the chlorantraniliprole and beta-cypermethrin treatment groups were significantly lower than those in the control group. Additionally, dinotefuran had a certain role in promoting oviposition in the F0 and F1 generations, which may stimulate the growth of offspring population and cause the resurgence of pests. The results provide a reference for the effective implementation of the IPM plan in the field to control S. frugiperda.