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In this study, a series of collagen–chitosan–eugenol (CO–CS–Eu) flow‐casting composite films were prepared using collagen from sturgeon skin, chitosan, and eugenol. The physicochemical properties, mechanical properties, microstructure, as well as antioxidant and antimicrobial activities of the composite membranes were investigated by various characterization techniques. The findings revealed that the inclusion of eugenol augmented the thickness of the film, darkened its color, reduced the transparency, and enhanced the ultraviolet light‐blocking capabilities, with the physicochemical properties of the CO–CS–0.25%Eu film being notably favorable. Eugenol generates increasingly intricate matrices that disperse within the system, thereby modifying the optical properties of the material. Furthermore, the tensile strength of the film decreased from 70.97 to 20.32 MPa, indicating that eugenol enhances the fluidity and ductility of the film. Added eugenol also exhibited structural impact by loosening the film cross‐section and decreasing its density. The Fourier transform infrared spectroscopy results revealed the occurrence of several intermolecular interactions among collagen, chitosan, and eugenol. Moreover, the incorporation of eugenol bolstered the antioxidant and antimicrobial capabilities of the composite film. This is primarily attributed to the abundant phenolic/hydroxyl groups present in eugenol, which can react with free radicals by forming phenoxy groups and neutralizing hydroxyl groups. Consequently, inclusion of eugenol substantially enhances the freshness retention performance of the composite film. Practical Application: ● The CO–CS–Eu film utilizes collagen from sturgeon skin, improving the use of sturgeon resources.● Different concentrations of eugenol altered its synergistic effect with chitosan.● The CO–CS–Eu film is composed of natural products with safe and edible properties. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ionotropic γ‐aminobutyric acid (GABA) receptor (GABAR) in an insect is the major inhibitory receptor and is one of the most important targets for insecticides. Due to the high spatiotemporal resolution of GABAR, the photopharmacological ligands acting on it in vertebrates but not insect have been developed. RESULTS: In this study, two types of photochromic ligands (PCLs) including DTFIPs (DTFIP1 and DTFIP2) and ABFIPs (p‐, m‐, and o‐ABFIP) were synthesized by incorporating photoswitch azobenzene or dithienylethene into fipronil (FIP), which is the antagonist of insect GABAR. Their photomodulation was measured by mosquito larval behavior, and their potential action mechanism was explored by the two‐electrode voltage clamp (TEVC) technique in vitro. DTFIP1 and m‐ABFIP exhibited the most significant difference of insecticidal activity by about 90‐ and 5‐fold to mosquito larvae between non‐irradiated and irradiated formation, respectively, and allowed for optical control of mosquito swimming activity. TEVC assay results indicated that m‐ABFIP and DTFIP1 enable optical control over the homomeric LsRDL‐type GABAR, which is achieved by regulating the chloride channel of resistance to dieldrin (RDL)‐type GABAR by photoisomerization. CONCLUSION: Our results suggested that PCLs synthesized from fipronil provide an alternative and precise tool for studying insect ionotropic GABARs and GABA‐dependent behavior. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Broflanilide has been registered in China for the control of Lepidoptera and Coleoptera pests, and is widely used to control the target pests at lethal and sublethal levels. The lethal and sublethal effects of broflanilide on the common cutworm (CCW) Spodoptera litura Fabricius, a representative Lepidopteran pest in agricultural crops, were examined to explore its ecological influence on pests. RESULTS: In F0, broflanilide had little influence on the hatchability of eggs, but significantly reduced the neonate survival rate. The lethal activity of broflanilide towards third‐instar larvae and adults was 0.13 mg kg–1 (LD50) and 3.59 mg L–1 (LC50) respectively at 48 h. After being treated with a sublethal dose (LD10 and LD30) of broflanilide, the duration of third‐ to sixth‐instar larvae and the mean fecundity of reproductive females were significantly increased, but pupation rate, weight of pupae and life‐cycle rate were significantly decreased. In F1, the duration of F1 larvae and the doubling time were prolonged, whereas the rates of pupation and the life cycle were decreased by 14.92% and 18.00%, respectively. The intrinsic rate of increase, finite rate of increase and net reproductive rate in the sublethal group were lower than in the control group. The relative fitness of F1 treated by LD10 and LD30 was 0.81 and 0.66, respectively. CONSLUSION: Broflanilide not only has highly lethal activity, but also suppresses the population growth and progeny of CCW, as a critical factor for guidelines of its usage in the field. [ABSTRACT FROM AUTHOR]

BACKGROUND: Neuroligin (NLG) protein is a nerve cell adhesion molecule and plays a key role in the precision apposition of presynaptic domains on inhibitory and excitatory synapses. Existing studies mainly focused on the function of NLG3 against the excitatory channel. However, the interaction between insect NLG3 and ionotropic GABA receptor, which is the main inhibitory channel, remains unclear. In this study, the Nlg3 of common cutworm (CCW), Spodoptera litura Fabricius, one important agricultural Lepidopteron, is selected to explore its function in the inhibitory channel. RESULTS: The SlNlg3 was obtained and the SlNLG3 contains the characteristic features including transmembrane domain, PDZ‐binding motif and type‐B carboxylesterases signature 2 motif. The SlNlg3 messenger RNA (mRNA) was most abundant in midgut, and exhibited multiple expression patterns in different developmental stages and tissues or body parts. Compared with the single injection of SlRDL1, the median effective concentration value of GABA in activating currents was smaller in Xenopus laevis oocytes co‐injected with SlRDL1 and SlNlg3. In addition, SlNlg3 could enhance the GABA‐induced current of homomeric SlRDL1 channel from −391.86 ± 15.41 to −2152.51 ± 30.09 nA. DsSlNlg3 depressed the expression level of SlNlg3 mRNA more than 64.29% at 6 h. After exposure to median lethal dose of fluralaner, the mortality of CCW injected with dsSlNlg3 was significantly decreased by 13.34% and 30.00% at 24 and 48 h, respectively, compared to injection of dsEGFP. CONCLUSION: NLG3 should have physiological function on ionotropic GABA receptor in vitro, which provided a favorable foundation for further research on the physiological function of Nlg gene in Lepidopteron. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The resistance to dieldrin gene (RDL) encodes the primary subunit of the insect ionotropic γ‐aminobutyric acid (GABA) receptor (GABAR), which is the target of phenylpyrazole and isoxazoline insecticides. The splice variants in exons 3 and 6 of RDL, which have been widely explored in many insects, modulate the agonist potency of the homomeric RDL GABAR and potentially play an important role in the development of insects. In the present study, four splice variants of exon 9 were identified in RDL of the small brown planthopper, Laodelphax striatellus (LsRDL), resulting in LsRDL‐9a, LsRDL‐9a', LsRDL‐9b, and LsRDL‐9c. LsRDL‐9a has one more amino acid (E, glutamic acid) compared with LsRDL‐9a', and LsRDL‐9b lacked two amino acids and had seven different amino acids compared with LsRDL‐9c. Two‐electrode voltage‐clamp recording on LsRDLs expressed in Xenopus oocytes showed that alternative splicing of exon 9 has significant impact on LsRDL sensitivity to the agonists GABA and β‐alanine, whereas no significant difference was observed in the potencies of the non‐competitive antagonists (NCAs) ethiprole and fluralaner on the splice variants. Our results suggest that alternative splicing of RDL exon 9 broadens functional capabilities of the GABAR in L. striatellus by influencing the action of GABA. [ABSTRACT FROM AUTHOR]

BACKGROUND: Two‐spotted spider mite (TSSM), Tetranychus urticae Koch, is one of the most serious pests of agricultural crops. Broflanilide exhibits high lethality against various pests and has been marketed worldwide under the Vedira and Tenebenal brands in 2020. Nevertheless, little information has been reported about its effects on agricultural mites. RESULTS: Broflanilide displayed higher toxicity to TSSM eggs (24 h LC50, 1.015 mg L−1) and adult females (24 h LC50, 2.062 mg L−1) than commercial acaricides, including cyflumetofen, bifenazate, and profenofos. In contrast, the adverse effects of broflanilide on the predatory mite, Typhlodromips swirskii Athias‐Henriot, was lower than those of fenpyroximate and abamectin. In the sublethal effect study, while adult females were treated with broflanilide, the number of eggs and longevity were reduced in LC10 and LC30 treatments; when eggs were treated with broflanilide, the egg duration and deutonymph duration were prolonged in LC30 treatment. A significant decrease in the total life span and duration and fecundity of adult females was observed in LC10 and LC30 treatments. Furthermore, the number of eggs per adult female was significantly reduced from 103.48 ± 3.69 in the control group to 69.42 ± 2.22 and 48.33 ± 1.75 in LC10 and LC30 treatments, respectively. In the greenhouse bioassay, broflanilide 5% suspension concentrate (MCI‐8007) showed excellent acaricidal activity to TSSM, with 99.22% corrected control, compared with the MCI‐8007 untreated group. CONCLUSION: Our results indicated that broflanilide has a high acaricidal activity to TSSM and significant inhibition to fecundity of adult female, and could be considered as a potential alternative for TSSM management. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Two‐spotted spider mite (TSSM), Tetranychus urticae Koch is a serious agricultural pest and has developed high levels of resistance to many acaricides. Hence, screening new acaricides is important in the control of TSSM. Fluralaner, a novel isoxazoline, has high activity against agricultural and ectoparasitic pests; however, little information is available about its effects on agricultural mites. Lethal and sublethal effects of fluralaner towards TSSM eggs and female adults were therefore evaluated in this study. RESULTS: Fluralaner exhibited higher activity towards TSSM female adults (LC50, 0.49 mg L−1) compared with commercial acaricides including fenpyroximate, pyridaben and hexythiazox, and also excellent activity towards eggs (LC50, 0.36 mg L−1). The results of a sublethal effect study showed a significant reduction in the duration and fecundity of female adults with increases in the tested concentrations. The net reproductive rate (R0) decreased to 67.34 ± 3.96 and 50.29 ± 3.40 offspring per individual in LC10 and LC30 treatments compared with control (108.31 ± 7.61 offspring per individual). The intrinsic rate of increase (r) and finite rate of increase (λ) in the controls (0.30 and 1.36 d−1) were significantly higher than in the LC30 treatment (0.25 and 1.29 d−1); whereas, they were almost identical to values for the LC10 treatment. No change in mean generation time (T) was observed at sublethal concentrations treatments. CONCLUSION: Our results demonstrated that fluralaner has high acaricidal activity and could be considered a potential acaricide for TSSM management. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Fluralaner, a novel pesticide that targets the γ‐aminobutyric acid (GABA) receptor (GABAR) subunit of resistant to dieldrin (RDL), exhibits strong potential to be an insecticide to control agricultural insect pests. However, the risk and action of fluralaner to economic insects, e.g., honeybee Apis mellifera Linnaeus, remains unclear. RESULTS: In this study, both oral and contact toxicity of fluralaner to honeybee were found to be 0.13 μg adult–1. Abamectin, dieldrin, ethiprole, α‐endosulfan, fipronil and fluralaner strongly inhibited the GABA‐induced current in A. mellifera RDL (AmRDL), expressed in Xenopus laevis oocytes, with median inhibitory concentration (IC50) values of 7.99, 868.1, 27.10, 412.0, 11.21 and 13.59 nM, respectively. The binding free energy and electrophysiological response of AmRDL and insecticides were opposite. The correlation values between toxicity (to A. mellifera) and binding free energy/electrophysiological inhibition (to AmRDL) were at a moderate level. CONCLUSION: In conclusion, we report for the first time the notable risk of fluralaner to honeybee in vivo and compared the actions of GABAR‐targeted insecticides on the AmRDL receptor. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Phenylpyrazole (fiprole) insecticides, including ethiprole, fipronil and flufiprole with excellent activity on rice planthoppers, are very important in Asia but resistance has developed after decades of use. The molecular mechanism of fipronil‐ but not ethiprole‐resistance has been previously studied in rice planthoppers. In our laboratory, a small brown planthopper Laodelphax striatellus strain with ethiprole‐resistance was cultured and the molecular mechanisms of ethiprole resistance and of cross‐resistance among fiprole insecticides were investigated. RESULTS: Ethiprole‐resistant L. striatellus has >5000‐fold resistance compared to the susceptible strain, and exhibits around 200‐fold cross‐resistance with fipronil and flufiprole. RDL genes were isolated from susceptible and ethiprole‐resistant L. striatellus and expressed in Xenopus oocytes. Electrophysiological studies showed fiprole insecticides inhibited γ‐aminobutyric acid (GABA)‐induced current with IC50 = 0.1–1.4 μM to LsRDL‐S homomers. In LsRDL‐R with A2′N mutation, only 1–13% inhibition was observed on treatment with 10 μM ethiprole, fipronil or flufiprole. Homology models indicate A2′N mutation allows crosslinking hydrogen bonding between Asn sidechains at the 2′ position around the channel pore, blocking insecticides from interacting near this position. In contrast, insecticides showed favorable binding near A2′ in wild‐type L. striatellus. CONCLUSION: Cross‐resistance is increasing for fiprole insecticides in L. striatellus and management strategies are necessary to minimize resistance. © 2018 Society of Chemical Industry N2′ mutation of RDL homomers allows crosslinking hydrogen bonds between sidechains of N2′ around channel pore, blocking fiproles from interacting near N2′. Insect management strategies are necessary to minimize resistance. [ABSTRACT FROM AUTHOR]

Fluralaner, as an isoxazoline insecticide, has been developed as antiparasitic (namely Bravecto®) with selective toxicity for insect versus mammals. Even though the toxic effect of fluralaner to several insects have been already examined, but also more agricultural and sanitary insects should be tested before it could be used widely. Four insects, including two agricultural insects, one sanitary insect and one stored product insect were tested in the present study. Compared to the broad-spectrum and high activity insecticide of fipronil, fluralaner showed mostly higher activity to tested pests, Chilo suppressalis, Tribolium castaneum, Spodoptera litura except Blattella germanica with topical application. Through summarizing and analyzing various published data, we concluded that, to date, the toxic activity of fluralaner to 19 insects from 11 orders were already examined, and fluralaner displayed excellent activity. Compared to fipronil, fluralaner mostly shows more excellent activity to tested insect with maximal 1.67 × 10 4 -fold difference so much. In the present study, the toxicity activity of fluralaner was compared to the broad-spectrum phenylpyrazole insecticide fipronil to tested insect pests and the results exhibited that fluralaner would be a novel alternative insecticide with broad insecticidal spectrum and be widely used in more other areas not only as veterinary drug. [ABSTRACT FROM AUTHOR]

Nuclear receptors (NRs), which belong to a superfamily of ligand-dependent transcription factors, play essential roles in gene regulation to affect numerous physiological pathways. Twenty NR genes were identified in Nilaparvata lugens by using genomic, transcriptomic and GenBank databases, and categorized into NR0-NR6 subfamilies according to standard nomenclature. Among them, three NR genes were classed into NR0, four into NR1, eight into NR2, one into NR3, one into NR4, two into NR5, and one into NR6, respectively. A phylogenetic tree of NRs from N. lugens and other representative species was constructed, which provided evolutionary insight into genetic distance. In order to investigate the NRs, which were induced by sulfoxaflor, time- and tissue-specific expression profiles of NR genes in fourth-instar nymphs were determined following LD 50 sulfoxaflor treatment (0.28 ng/insect) and compared with control samples. NlUSP , NlE78 , NlTLL , NlHR51 , NlHR83 , NlPNR and NlFTZ-F1 were highly expressed following 12–48 h of sulfoxaflor treatment. NlHR39 and NlDSF transcripts were detected in the head and the thorax, respectively. High-level and constitutive expression of NlHR3 , NlTLL , NlHR83 , NlFTZ-F1 and NlHR4 were found in the abdomen. Feeding of dsRNAs reduced the expression of NlHR3 , NlUSP , NlTLL , NlHR83 , NlPNR , NlFTZ-F1 and NlHR4 (35.48–49.77%) and caused significant nymph mortality (69.21–81.45%). These NRs, considered as insecticide targets, may play important function in sulfoxaflor detoxification. [ABSTRACT FROM AUTHOR]

BACKGROUND Osthol is a natural coumarin and lead compound that has been developed into commercial fungicides in China. Natural coumarins comprise five major subtypes: simple coumarins, linear furanocoumarins, angular furanocoumarins, linear pyranocoumarins and angular pyranocoumarins. Studies pertaining to the antifungal activities of linear pyranocoumarins are few, and no reports exist for the antifungal activities of angular pyranocoumarins. In order to discover more antifungal natural coumarins, we synthesised a series of simple natural coumarins and isolated several plant-based furanocoumarins and pyranocoumarins using previously described methods. The compounds were biologically evaluated against some plant fungal pathogens. RESULTS Several of the 35 coumarins evaluated here exhibited strong activities against specific fungal species, including compound 25 (Pd-D-V, a linear pyranocoumarin), compound 26 (libanorin, an angular furanocoumarin) and compound 34 (disenecioyl khellactone, an angular pyranocoumarin). Compound 25 exhibited a high activity against Sclerotinia sclerotiorum ( EC50 = 13.2 µg mL−1); compound 34 displayed a strong antifungal activity against Botrytis cinerea ( EC50 = 11.0 µg mL−1). CONCLUSION This study demonstrates that several natural coumarins (one linear pyranocoumarin and one angular pyranocoumarin in particular) exhibit strong antifungal activities. These results call for further studies, where these coumarins can be examined as potential lead compounds for developing novel antifungal agents. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Rhizoctonia cerealisandBipolaris maydisare fungal plant pathogens that cause enormous agricultural losses of wheat and maize.Bacillus amyloliquefaciensPEBA20 inhibited mycelial growth and spore germination of the pathogens and reduced fungal infections in wheat and maize, indicating its potential for application as a biocontrol agent. [ABSTRACT FROM AUTHOR]

N6‐methyladenosine (m6A) is the most prevalent modification in cellular RNA which orchestrates diverse physiological and pathological processes during stress response. However, the differential m6A modifications that cope with herbivore stress in resistant and susceptible crop varieties remain unclear. Here, we found that rice stem borer (RSB) larvae grew better on indica rice (e.g., MH63, IR64, Nanjing 11) than on japonica rice varieties (e.g., Nipponbare, Zhonghua 11, Xiushui 11). Then, transcriptome‐wide m6A profiling of representative resistant (Nipponbare) and susceptible (MH63) rice varieties were performed using a nanopore direct RNA sequencing approach, to reveal variety‐specific m6A modifications against RSB. Upon RSB infestation, m6A methylation occurred in actively expressed genes in Nipponbare and MH63, but the number of methylation sites decreased across rice chromosomes. Integrative analysis showed that m6A methylation levels were closely associated with transcriptional regulation. Genes involved in herbivorous resistance related to mitogen‐activated protein kinase, jasmonic acid (JA), and terpenoid biosynthesis pathways, as well as JA‐mediated trypsin protease inhibitors, were heavily methylated by m6A, and their expression was more pronounced in RSB‐infested Nipponbare than in RSB‐infested MH63, which may have contributed to RSB resistance in Nipponbare. Therefore, dynamics of m6A modifications act as the main regulatory strategy for expression of genes involved in plant–insect interactions, which is attributed to differential responses of resistant and susceptible rice varieties to RSB infestation. These findings could contribute to developing molecular breeding strategies for controlling herbivorous pests. [ABSTRACT FROM AUTHOR]

The ionotropic γ-aminobutyric acid (iGABA) receptor is commonly considered as a fast inhibitory channel and is an important insecticide target. Since 1990, RDL, LCCH3, and GRD have been successively isolated and found to be potential subunits of the insect iGABA receptor. More recently, one orphan gene named 8916 was found and considered to be another potential iGABA receptor subunit according to its amino acid sequence. However, little information about 8916 has been reported. Here, the 8916 subunit from Chilo suppressalis was studied to determine whether it can form part of a functional iGABA receptor by co-expressing this subunit with CsRDL1 or CsLCCH3 in the Xenopus oocyte system. Cs8916 or CsLCCH3 did not form functional ion channels when expressed alone. However, Cs8916 was able to form heteromeric ion channels when expressed with either CsLCCH3 or CsRDL1. The recombinant heteromeric Cs8916/LCCH3 channel was a cation-selective channel, which was sensitive to GABA or β-alanine. The current of the Cs8916/LCCH3 channel was inhibited by dieldrin, endosulfan, fipronil, or ethiprole. In contrast, fluralaner, broflanilide, and avermectin showed little effect on the Cs8916/LCCH3 channel (IC 50 s > 10 000 nM). The Cs8916/RDL1 channel was sensitive to GABA, but was significantly different in EC 50 and I max for GABA to those of homomeric CsRDL1. Fluralaner, fipronil, or dieldrin showed antagonistic actions on Cs8916/RDL1. In conclusion, Cs8916 is a potential iGABA receptor subunit, which can interact with CsLCCH3 to generate a cation-selective channel that is sensitive to several insecticides. Also, as Cs8916/RDL1 has a higher EC 50 than homomeric CsRDL1, Cs8916 may affect the physiological functions of CsRDL1 and therefore play a role in fine-tuning GABAergic signaling.