Search Results (95)

Root-knot nematode (Meloidogyne incognita) is a globally destructive plant-parasitic nematode that severely impedes the sustainable production of horticultural crops. Metabolic reprogramming in plant roots represents the host response to M. incognita infection that can also be exploited by the nematode to facilitate its parasitism. In this study, untargeted metabolomics was employed to analyze metabolic changes in cucumber roots following nematode inoculation, with the goal of identifying differentially accumulated metabolites that may influence M. incognita behavior. Metabolomic analysis revealed that M. incognita significantly altered the cucumber root metabolome, triggering an accumulation of lipids and organic acids and enriching biotic stress-related pathways such as alkaloid biosynthesis and linoleic acid metabolism. Among differentially accumulated metabolites, myristic acid and hexadecanal were selected for further study due to their potential roles in nematode inhibition. In vitro assays demonstrated that both metabolites suppressed egg hatching and reduced infectivity of M. incognita, while pot experiments indicated a correlation between their application and reduced root gall formation. Chemotaxis assays further revealed that both metabolites exerted repellent effects on the chemotactic migration of M. incognita J2 and suppressed the transcriptional expression of two motility-and feeding-related neuropeptides, Mi-flp-1 and Mi-flp-18. In conclusion, this study demonstrates the significant potential of differentially accumulated metabolites induced by M. incognita infection for nematode disease control, achieved by interfering with nematode chemotaxis and subsequent infection. This work also provides deeper insights into the metabolomic mechanisms underlying the cucumber-M. incognita interaction. Full article

Background/Objectives: Fish eggs activated with UV-irradiated spermatozoa and exposed to the High Hydrostatic Pressure (HHP) shock to inhibit first cell cleavage develop as gynogenetic Doubled Haploids (DHs) that are fully homozygous individuals. Due to the expression of the recessive genes and side effects of the gamete treatment, survival of fish DHs is rather low, and most of the mitotic gynogenotes die before hatching. Nevertheless, as maternal gene products provided during oogenesis control the initial steps of embryonic development in fish, a maternal effect on the survival of gynogenotes needs to be also considered to affect efficiency of gynogenesis. Thus, the objective of this research was to apply an RNA-seq approach to discriminate transcriptional differences between rainbow trout (Oncorhynchus mykiss) eggs with varied abilities to develop after gynogenetic activation. Methods: Gynogenetic development of rainbow trout was induced in eggs originated from eight females. Maternal RNA was isolated and sequenced using RNA-Seq approach. Survival rates of gynogenotes and transcriptome profiles of eggs from different females were compared. Results: RNA-seq analysis revealed substantial transcriptional differences between eggs originated from different females, and a significant correlation between the ability of the eggs for gynogenesis and their transcriptomic profiles was observed. Genes whose expression was altered in eggs with the increased survival of DHs were mostly associated (GO BP) with the following biological processes: development, cell differentiation, cell migration and protein transport. Some of the genes are involved in the oocyte maturation (RASL11b), apoptosis (CASPASE 6, PGAM5) and early embryogenesis, including maternal to zygotic transition (GATA2). Conclusions: Inter-individual variation of the transcription of maternal genes correlated with the competence of eggs for gynogenesis suggest that at least part of the mortality of the rainbow trout DHs appear before activation of zygotic genome and expression of the lethal recessive traits. Full article

Bis(4-hydroxyphenyl) methane (BPF), as a bisphenolic compound, has toxic effects on organisms such as endocrine disruption and immobilization of growth and development. This study evaluated the effect concentrations of BPF on Chironomus tentans and investigated the impact of BPF exposure at various sub-lethal concentrations on the growth, development, and reproductive capacity of different instars of C. tentans. The results demonstrated that exposure at concentrations of 2.0, 2.5, 3.0, and 4.0 mg·L⁻¹ delayed pupation, inhibited the development of imaginal discs, and caused an initial rise followed by a decline in the expression levels of genes related to larval development (ecr, usp, e74). Additionally, exposure at concentrations of 1.0, 1.5, and 2.0 mg·L⁻¹ led to fluctuations in the expression levels of genes related to adult development and reproduction (ecr, kr-h1, foxo, inr, pdk, akt, and vg) in both female and male adults, with varying degrees of effect. Furthermore, BPF exposure inhibited male fertility, causing significant damage to the gonadal tissues, though it did not affect the final hatching of eggs. These findings indicate that BPF exhibits developmental and reproductive toxicity in C. tentans, with 2.0 mg·L⁻¹ identified as the lowest effective concentration at which BPF affects pupation in midges. Full article

Plant-parasitic nematodes remain a significant challenge to agriculture and horticulture. Unfortunately, there is a lack of rapid, efficient and eco-friendly control methods. Nanomaterials, therefore, appear to be a promising source of new plant protection strategies. In the current study, two nanosystems—based on one-component (Ag) or two-component (AgZn) colloidal systems—and an aqueous solution of AgNO₃, were explored for their potential in nematode control, using Meloidogyne incognita—the most economically important root-knot nematode—as a model nematode. In vitro laboratory tests demonstrated high efficacy of all the tested compounds towards M. incognita. Incubation with an extremely low concentration of silver compounds (0.05 ppm) resulted in a 100% reduction of the M. incognita invasive larvae viability, as well as a 100% inhibition of the egg hatch process. Preliminary tests also showed no negative impact of tested compounds on seed germination. Thus, the nanosystems tested within this study offer a promising alternative to the current methods used for nematode control. Full article

Gastrointestinal nematode infections significantly impact small ruminant production, causing substantial economic losses worldwide. The rising resistance to anthelmintics has led to the search for alternative treatments, including phytotherapeutic approaches. This study investigates the chemical composition and anthelmintic activity of crude extracts and fractions from Simarouba berteroana, an endemic plant from Hispaniola, against a multidrug-resistant isolate of Haemonchus contortus. Chemical analyses revealed high contents of phenolic compounds, tannins, and flavonoids and confirmed the presence of 22 quassinoids, 5 phytosterol lipids, 3 terpenoid quinones, 3 alkaloids, and 1 naphthoquinone. The hydroalcoholic and iso-butanol fractions showed the strongest egg hatching inhibition (IC₅₀ = 0.93 and 1.21 mg/mL, respectively), while hexane fractions were less effective (p < 0.05). Fluorescence microscopy showed that the extracts and fractions adhered to eggshells, causing evisceration and cuticle detachment in hatched larvae. All extracts, except for hexane fractions, inhibited larval exsheathment at 0.3 mg/mL, with phenolic compounds being responsible for this effect. These results provide the first evidence of the ovicidal and larval exsheathment inhibition activities of S. berteroana extracts and fractions against H. contortus, highlighting their potential in managing gastrointestinal nematodes in small ruminants. Further in vivo studies are needed to confirm these findings. Full article

Gastrointestinal nematodes (GINs) inflict significant economic losses on sheep and goat farming globally due to reduced productivity and the development of anthelmintic resistance. Sustainable control strategies are urgently needed including the exploration of medicinal plants as safer alternatives to chemical anthelmintics. This genus of plants is used for anti-inflammatory, antioxidant, and antimicrobial activities. In this study, we aimed to evaluate the anthelmintic activities of Nepeta racemosa Lam. MeOH extract, n-hexane, dichloromethane (DCM), ethyl acetate (EtOAc), n-buthanol (n-BuOH) and aqueous (H₂O) subextracts, and quantify rosmarinic acid in the active extract by the HPLC method, and perform in silico molecular docking studies of rosmarinic acid to examine its binding interactions with tubulin. The anthelmintic activity of the plant extracts on gastrointestinal nematode eggs and larvae (L3) of the sheep was assessed using in vitro test methods such as the egg hatch assay and larval motility assay, conducted over a 24 h period (1, 2, 3, 4, 6, 8, 24). All extracts exhibited 100% effectiveness in the egg hatch inhibition assay, regardless of concentration (50–1.5625 mg/mL). The EtOAc subextract shows the highest effectiveness at 79.66%, followed by the MeOH extract at 74.00%, water at 64.00%, n-hexane at 67.00%, and DCM at 61.00%, and the lowest effectiveness is observed with n-BuOH at 51.66% in the larval motility assay. The major compound of EtOAc extract, the most active extract of N. racemosa, was determined as rosmarinic acid and its amount in the extract was determined as 14.50 mg/100 mg dry extract. The amount of rosmarinic acid in the MeOH extract was found to be 0.21 mg/100 mg dry extract. n-Hexane, DCM, n-BuOH, and H₂O extracts’ rosmarinic acid content was lower than the LOQ value. As tubulin plays an important role in the mechanism of anthelmintics, the major compound of the most active extract (NR-EtOAc) rosmarinic acid was docked onto the colchicine-binding site of the tubulin (5OV7) protein. Rosmarinic acid showed a similar activity spectrum to the anthelmintic drug albendazole. The discovery of low-cost and low-toxicity anthelmintic compounds is very important. Full article

This study investigates the nematicidal efficacy of Purpureocillium lilacinum strain (AUMC 10620) combined with avermectin (B1a and B1b) against the citrus nematode Tylenchulus semipenetrans, both in vitro and in vivo. Laboratory experiments tested four concentrations of P. lilacinum (2.5, 5, 10, and 15 × 10⁷ spores/mL) mixed with 250 ppm avermectin, assessing their effects on nematode juveniles (J2) and eggs. Results showed significant increases in juvenile mortality and egg hatching inhibition with the combined treatments compared to individual applications. The highest concentration (15 × 10⁷ spores/mL + 250 ppm avermectin) achieved 100% juvenile mortality and 83.33% egg hatching inhibition after 72 h. Field trials confirmed the superior efficacy of the combined treatment, with P. lilacinum (15 × 10⁷ spores/mL) and avermectin (1000 ppm) reducing nematode populations by 70.85% in mandarin trees and 70.77% in sweet orange trees after three weeks, compared to the 83.59% and 81.76% reduction, respectively, achieved by oxamyl. These findings suggest that mixtures of P. lilacinum and avermectin can serve as effective, eco-friendly alternatives for controlling nematodes in citrus orchards. Full article

New alternatives for controlling resistant populations of gastrointestinal nematodes are being studied, including the use of plant compounds and biological control with nematophagous fungi. The objective of this study was to evaluate the in vitro anthelmintic effect of linalool and its association with the fungus Duddingtonia flagrans (isolated AC001) in controlling gastrointestinal nematodes in sheep. The ovicidal activity of linalool was assessed via the Egg Hatch Test (EHT), and the larvicidal activity of linalool, alone and in combination with D. flagrans conidia, was evaluated via the Larval Motility Inhibition Test (LMIT) on infective larvae (L3). In the EHT, 100% inhibition occurred (at 1.25 and 2.5 mg/mL), with an LC50 of 0.49 mg/mL. In the LMIT, linalool alone inhibited 100% of larval motility (at 4% and 8%), with an LC50 of 0.42% or 4.2 mg/mL. In the combination of linalool with D. flagrans, there was a significant reduction in larvae, starting at 24 h, with 100% reduction after 14 days, thus being more effective in reducing L3 compared to the use of the fungus alone. It is concluded that linalool exhibits ovicidal and larvicidal activity, and its association with D. flagrans enhances the fungal predation capacity and potentiates anthelmintic efficacy. Full article

Tuta absoluta is a major pest, damaging tomato crops in many countries. Spinetoram, a novel insecticide, is increasingly used for the management of various insect pests. However, limited information is available on its lethal effects on T. absoluta. Therefore, this study was carried out to evaluate the toxicity of spinetoram concentrations in T. absoluta by exposing third-instar larvae to this insecticide through leaf-dipping bioassays under laboratory conditions. The results showed that sublethal spinetoram concentrations (LC₁₀ and LC₂₀) extended the developmental duration of the larval and pupal stage, as well as the oviposition period, and decreased the pupal weight, pupation and eclosion rates, fecundity, sex ratio, and egg-hatching rate compared to the control group. LC₁₀ and LC₂₀ treatments up-regulated the activity of superoxide dismutase and catalase antioxidant enzymes in T. absoluta larvae by 51.14–88.72% and 39.34–87.76% at 12 h, 62.71–96.68% and 37.38–39.92% at 24 h, and 41.78–53.34% and 19.44–48.39% at 48 h, respectively, compared to the control. Conversely, the LC₁₀ and LC₂₀ treatments inhibited the activities of detoxifying enzymes, i.e., carboxylesterase (14.72–34.95%), acetylcholinesterase (9.02–48.86%), glutathione S-transferase (19.40–43.19%), and mixed-function oxidase (18.18–25.93%). These findings indicate that lethal concentrations of spinetoram influence the population dynamics of T. absoluta by reducing their survival and developmental potential and inhibiting the activity of detoxifying enzymes. Full article

Diaphania indica (Lepidoptera: Crambidae) is one of the most important pests infesting many cucurbitaceous vegetables. During the rearing of insect eggs, we observed a fungal infection in these insect eggs which causes the death of pests. Therefore, this work aimed to isolate and identify this fungus by amplifying the internal transcribed spacer (ITS) region of the rDNA, as well as evaluating the efficiency of this fungus in control. Aspergillus flavus, ‘PP125556’, showcased robust pathogenicity against a range of D. indica pests. The results showed that colonies of ‘PP125556’ cultivated on potato dextrose agar (PDA) exhibited distinctive morphological characteristics, transitioning from pristine white to verdant green. Bioassays demonstrated concentration-dependent mortality rates of D. indica larvae and adults when exposed to varying concentrations of ‘PP125556’ conidia, with the highest concentration (1 × 10⁹ conidia/mL) inducing significant death, with the highest mortality (53.06% for eggs, 70.57% for larvae, and 86.65% for adults). Furthermore, examination under a stereomicroscope revealed conspicuous external symptoms in infected larvae, including reduced mobility, darkened body pigmentation, and the emergence of white hyphae, indicative of mortality. Additionally, infected eggs exhibited inhibited hatching and the emergence of green hyphae, while infected adults displayed mortality and white hyphae colonization, underscoring the potent biocontrol efficacy of A. flavus ‘PP125556’ against D. indica across diverse developmental stages. Full article

Background: Eggshell contamination threatens the viability of hatching eggs. This contamination can be caused by harmless, opportunistic, or pathogenic bacteria. Although necessary, the use of synthetic antibiotics to treat eggshells can present several significant problems: They can be toxic and damage the shell, and, most worryingly, they can lead to bacterial resistance. Faced with these challenges, the objective of this research was to create and test a sanitizing plan for hatching eggs using essential oils derived from Citrus aurantifolia (CAEO), Ocimum basilicum (OBEO), or Allium sativum (ASEO). Methods: Sanitizing solutions containing specific concentrations of these essential oils were prepared, and their antimicrobial properties and contributions to poultry safety and hatching parameters were investigated. Results: The bacterial load was reduced in eggshells sanitized with essential oils, and the degree of bacterial inhibition, along with their safety profile, may be directly related to optimal hatchability rates, lower incidences of contaminated dead embryos, and the hatching of healthy chicks. Conclusions: Together, these results reinforce the importance of essential oils in the development of effective and safe treatments for managing hatching eggs. Full article

Background/Objectives: Heterodera avenae is a highly significant plant-parasitic nematode, causing severe economic losses to global crop production each year. Trichoderma species have been found to parasitize nematodes and control them by producing enzymes that degrade eggshells. The T. longibrachiatum T6 (T6) strain has been demonstrated the parasitic and lethal effects on H. avenae cysts and eggs, associated with the increased serine protease activity and trypsin-like serine protease gene (PRA1) expression. Methods: Our present study aimed to purify the recombinant PRA1 protease through a prokaryotic expression system and identify its nematicidal activity. Results: The recombinant PRA1 protease was identified as S1 family trypsin-like serine protease, with a molecular weight of 43.16 kDa. The purified soluble protease exhibited the optimal activity at 35 °C and pH 8.0, and also demonstrating higher hydrolytic ability toward casein and skimmed milk. Meanwhile, the Ca²⁺ and Mg²⁺ enhanced its activity, while the inhibitor PMSF significantly reduced it. The contents of H. avenae eggs leaked out after treatment with the recombinant PRA1 protease, with egg hatching inhibition and relative hatching inhibition rates at 70.60% and 66.58%, respectively. In contrast, there was no sign of content dissolution, and embryos developed normally in the control group. Conclusions: Our present study revealed that the PRA1 protease of T6 strain has a lethal effect on H. avenae eggs, which providing a theoretical basis for developing biocontrol agents to control nematodes. Full article

Ticks pose a significant threat due to their ability to lay thousands of eggs, which can persist in the environment for extended periods. While the impact of various compounds on adult and larval ticks has been studied, research on their efficacy against tick eggs is limited. This study evaluated the ovicidal activity of commercial acaricides, disinfectants, and natural products against Rhipicephalus annulatus eggs using the egg hatch assay (EHA). Deltamethrin and cypermethrin caused a non-significant inhibition of hatching (IH%), even at concentrations higher than the recommended levels. By contrast, the acaricides chlorpyrifos, phoxim, and amitraz significantly inhibited hatching at all tested concentrations. Ivermectin also demonstrated significant IH% at various concentrations but did not fully inhibit the hatching process. Among the disinfectants tested, Virkon-S^®, TH4, and Chlorox showed insignificant effects, whereas formalin achieved an IH% of only 34.1% at a high concentration of 200 mg/mL. Natural products, carvacrol and thymol, exhibited significant ovicidal activity, with a significant IH%. In a semi-field application, phoxim (0.5 mg/mL) and deltamethrin (0.05 mg/mL) were sprayed on tick eggs on pasture soil from a farm. The results indicated that phoxim-treated eggs had a 40% IH%, while deltamethrin-treated eggs showed only an 8.79% IH%. In conclusion, the acaricides amitraz, phoxim, and chlorpyrifos, as well as the natural products carvacrol and thymol, caused significant toxicity to R. annulatus eggs. Full article

This study attempted to evaluate the ovicidal activity of single-component formulations and combination formulations of lemongrass and star anise essential oils (EOs) and their main constituents against housefly eggs. The efficacies of the combinations were compared with those of single-component formulations and α-cypermethrin. Safety bioassays of all treatments and α-cypermethrin on non-target predators—guppy and molly—were conducted. Two combinations: 1% lemongrass EO + 1% trans-anethole and 1% star anise EO + 1% geranial, exhibited a strong ovicidal activity with an inhibition rate of 94.4 to 96.2%. They were 1.1 times as effective as α-cypermethrin. The two combinations also showed high synergistic activity compared to single-component formulations, with a high synergistic index and a high increased inhibition value of 37.4 to 57.7%. All EO treatments were benign for all non-target aquatic species with a high 50% lethal time (LT₅₀) and safety index. In contrast, α-cypermethrin was highly toxic to them with a low LT₅₀. The morphological abnormalities observed in housefly eggs at death were those such as the shrivelling of the eggs, aberrations and damage to the eggshells, hatching lines, aeropyles, plastron, and micropyle. The potential of these two combinations as a cypermethrin replacement is compelling. Full article

Spodoptera frugiperda was used to investigate its role as a trehalase inhibitor of three new thiothiazolidone compounds—6d, 6e, and 6f. The development and reproduction of S. frugiperda were investigated to evaluate the potential of these compounds as a novel pesticide for pest control. Compounds 6d, 6e, and 6f were injected into larvae and female pupae. Molecular changes in trehalose and chitin metabolism genes were monitored. Pupal trehalase activity, the female pupal emergence rate, ovarian development, and SfVg and SfVgR gene expression levels were assessed. The results revealed that all three compounds significantly inhibited trehalase activity in the larvae. The expression of TRE was significantly downregulated, and compounds 6d and 6f significantly downregulated the expression of TRE2. Treated larvae exhibited significantly decreased survival rates and a higher incidence of abnormalities. The egg production and hatching rates were markedly diminished by the inhibitors, and the ovaries displayed blackening and clumping. These compounds exhibit promise as eco-friendly insecticides, but further experiments are required to test their multifaceted capabilities. Full article