Entomological Research最新文献

Silk fibroin from Bombyx mori has traditionally been utilized for garment production; however, recently, it has become feasible to manufacture edible and cosmetic products using this material. Gamma-ray irradiation can improve physiological activity through the modification of the structure of proteins in biological materials. In this study, we examined whether gamma ray-irradiated fibroin protein (gFP) has a protective effect on tumor necrosis factor alpha (TNF-α)-induced cellular stress through a change in protein structure. First, we confirmed that the structure of FP was changed by gamma-ray irradiation using electrophoresis, UV spectra and Fourier-transform infrared spectroscopy (FT-IR). We further investigated the cytoprotective potential of 20 kGy-irradiated fibroin protein (gFP20) in human skin keratinocytes (HaCaT cells) exposed to extracellular stress. gFP20 effectively decreased TNF-α-induced matrix metalloproteinase-1 (MMP-1) overexpression and restored reduced type-1 procollagen in HaCaT cells. This reduction occurred concomitantly with suppressed nuclear factor-κB (NF-κB) nuclear translocation, resulting in a decreased level of inflammatory mediator and pro-inflammatory cytokines. Furthermore, gFP20 protected cells from TNF-α-induced oxidative stress by attenuating reactive oxygen species (ROS) overexpression and increasing the production of the antioxidant enzyme heme oxygenase-1 (HO-1) through the stimulation of the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) into the nucleus. Taken together, our findings indicate that low-dose irradiated fibroin protein (gFP20) could be considered as a functional material for skincare products.

Selective herbicides are used to control undesirable vegetation or weeds in fields without harming crops. Herbicide use for weed management can directly impact the densities of insect pests in agricultural communities as a result of insect mortality during and immediately after application. In insects, the glutathione S-transferase (GST) enzyme is involved in both the detoxification process and the defense of cellular membranes against oxidative damage. In this study, two TmGSTs (TmGST-iso1 and TmGST-iso2) were identified and characterized to elucidate the GST family in Tenebrio molitor. Among the developmental stages of T. molitor, eggs had the highest expression levels of TmGST-iso1. TmGST-iso2 expression was highest in the pre-pupal stage. TmGST-iso1 expression was high in the guts of early and late larvae, whereas TmGST-iso2 expression was not observed in early larvae. Adults, both male and female, had the highest levels of TmGST-iso1 mRNA expression in the gut and reproductive organs, and the highest levels of TmGST-iso2 expression in the reproductive organs. Quantitative polymerase chain reaction was used to investigate the impact of treatment with butachlor on the mRNA expression of TmGST-iso1 and TmGST-iso2 in larvae. TmGST-iso1 expression increased in the butachlor-treated group after 3 and 24 h, whereas TmGST-iso2 expression peaked at 24 h after treatment. This study provides vital information about the detoxifying activities of T. molitor.

Wasp venom is rich in bioactive substances, such as proteins, peptides, and small molecules. The venom significantly affects the mammalian cardiovascular, nervous, and immune systems, causing mild to severe symptoms following stings. It exhibits both procoagulant and anticoagulant activities, and significant research has identified its ability to modulate the mammalian coagulation system. Active substances that inhibit clotting have been identified and purified through patient case reports and experimental studies. This study reviewed the findings on how wasp venom interacts with platelets and coagulation factors, such as fibrinogen and prothrombin, and demonstrated its dual influence on the coagulation cascade. This highlights the potential of the venom in therapeutic applications, especially as an anticoagulant, as evidenced by the inhibition of coagulation factors and prolonged clotting times after envenomation, suggesting its utility in developing novel anticoagulant therapies. This review focuses on the anticoagulant effects of social wasp venom, which is prevalent in sting incidents, summarizing the research and observations on its therapeutic potential. This emphasizes the significance of further studies to identify and utilize venom components as innovative anticoagulant treatments.

Melon thrips, Thrips palmi (Thysanoptera: Thripidae), is a serious insect pest in crop productions, and synthetic chemicals are frequently used to control them. However, this practice causes residual issue in nature and makes melon thrips acquire strong resistance. To overcome these problems, a group of entomopathogenic fungi could be used as an alternative for controlling melon thrips. In this work, a total of 100 fungal isolates from soil in four different regions of Korea were isolated and subjected to virulence assays against melon thrips. Twenty-five highly virulent fungal isolates, which showed 100% mortality 6 days after treatment, were determined. Liquid-cultured filtrates of the selected isolates were further used to investigate their insecticidal activity against melon thrips, and of the 25 selected isolates finally seven isolates including Metarhizium spp. and Fusarium spp. showed high insecticidal activity in a dose-dependent manner. Under a thermal stress at 121°C, culture filtrates of the seven isolates still kept their insecticidal activities. When liquid-cultured spores were exposed to 45°C, spores of Fusarium isolates were resistant to the thermal stress, but those of Metarhizium isolates were susceptible to the stress. The culture filtrates of Fusarium isolates did not show any phytotoxicity to the tomato plants, followed by no phytotoxicity of liquid-cultured spores, although mycotoxins need to be further clearly characterized. This work suggests that entomopathogenic Fusarium isolates are competitive in virulence against melon thrips and production of insecticidal metabolites compared to Metarhizium, and particularly attractive in sporal resistance against thermal stress, significantly stronger than Metarhizium.

Mosquitoes around the world spread diseases like malaria, dengue, zika, lymphatic filariasis and arboviruses, which are dangerous to human health and the economy. Eventually, mosquitoes develop resistance to synthetic chemical insecticides and, moreover, these insecticides have adverse environmental impacts, accumulating in soils and in the food chain. So, researchers are searching for better vector control tools from biological sources such as plants, bacteria, fungi, viruses and other predators. Eco-friendly methods that use entomopathogenic fungi to reduce vector-borne disease burdens are becoming more popular because they are selective and safe for the environment. Based on existing literature, several microbial agents show potential for the biocontrol of mosquitoes. With advances in genetic recombination and transformation techniques, in the ongoing battle against insecticide-resistant mosquitoes, genetically engineered fungal biopesticides represent a cutting-edge solution. These biopesticides are the result of novel genetic changes that improve the ability of fungi to target and kill mosquitoes. These fungi can effectively combat mosquito populations by introducing genes that produce insecticidal proteins or toxins. This method has several advantages, including a lower environmental impact, because the fungi are highly specific to mosquitoes and are harmless to non-target organisms. It also helps to reduce the problem of insecticide resistance because the fungi have a unique mode of action. These biopesticides hold great promise for reducing mosquito-borne diseases while minimizing environmental damage and combating resistance. This review article discusses various entomopathogenic fungal pathogens that can act as biocontrol agents and their mode of action against mosquitoes. We discus recent advances in entomopathogenic fungi-secreted effector molecules for suppressing host immunity and progress in the development of transgenic mosquito-killing fungi.

Ectropis grisescens is a notorious pest in tea plantations. The control of E. grisescens relies on synesthetic pesticides but the resurgence is always accompanied by increasing resistance. Therefore, it is crucial to use biological control to reduce the damage caused by E. grisescens. Here, we collected soil from a tea plantation, used Galleria mellonella as a bait insect and successfully isolated one entomopathogenic fungus. The isolated colony was initially identified as Cordyceps sp. using morphological observation. ITS-rDNA sequence amplification and sequencing, molecular database comparisons, and phylogenetic analysis proved this fungus as a new species and thus named Cordyceps sp. WZFW1. Further virulence test of Cordyceps sp. WZFW1 against E. grisescens was evaluated under laboratory conditions. Lethal concentration was 5.74 × 10⁶ spore/mL with a confidence level of 2.32 × 10⁶ ~ 1.79 × 10⁷ and lethal time was 2.98 days at 10⁸ spore/mL and 7.47 days at 10⁷ spore/mL, indicating Cordyceps sp. WZFW1 was effective at controlling E. grisescens. Our findings are significant as they contribute to the application of new entomopathogenic fungi (EPF) species as biocontrol agents, promoting eco-friendly pest management practices.

Innate immunity is the immediate and exclusive defense mechanism in invertebrates. It acts against foreign agents and pathogens. In insects, this defense mechanism involves a combination of humoral and cellular responses, orchestrated by specific recognition receptors and the activation of various signaling pathways. Remarkably, Toll and Toll-related proteins play a pivotal role in insect immunity by inducing the production of antimicrobial peptides (AMPs) in response to pathogen attacks. Toll receptors, which are type I transmembrane proteins, significantly affect insect development and the innate immune response, primarily via the nuclear factor kappa-B signaling pathway. The Malpighian tubules of insects play a crucial role in waste elimination, hemostasis maintenance, and immune defense. The Toll signaling pathway in Malpighian tubules is mainly involved in the production of AMPs. This review provides valuable insights into the mechanisms of the Toll signaling pathway and the morphological and physiological attributes of Malpighian tubules. Moreover, it discusses the classification and functionalities of AMPs synthesized in Malpighian tubules in response to pathogens, thereby contributing to our understanding of innate immunity in insects.

MicroRNAs (miRNAs) are conserved noncoding small RNAs that play essential regulatory roles in gene function by regulating target genes. Pardosa pseudoannulata is an important natural predatory enemy of insect pests and plays a significant role in controlling pests in rice fields, with temperature having a significant impact on their growth and development. To understand the response of miRNAs to temperature stress in P. pseudoannulata, we performed miRNA identification analyses of adult spiders exposed to 10°C and 40°C for 12 h, as low-temperature and high-temperature treatment groups, respectively. We obtained 54.74 M clean reads from 69.84 M raw reads after filtering out low-quality reads, and 78 miRNAs including 13 novel miRNAs were identified from three small RNA libraries (10°C, 25°C and 40°C). At the low temperature and the high temperature, eight (one upregulated and seven downregulated) and ten (nine upregulated and one downregulated) differentially expressed miRNAs were identified, respectively. These differentially expressed miRNAs negatively regulated 43 and 12 target mRNA (the unigenes in our previous transcriptome sequence data) in response to low- and high-temperature stress, respectively. These target genes are mainly involved in translation, ribosome structure and biotransformation, as well as the generation and conversion of energy. This study represents the first report of miRNA identification related to the Araneae spider species in response to temperature stress. These results will greatly facilitate our understanding of the physiological and biochemical mechanisms of spiders in response to temperature stress, which might be beneficial for the conservation and utilization of this species as an important natural insect enemy of pests in rice ecosystems.

The present study aimed to investigate the preventive role of Protaetia brevitarsis seulensis (P. brevitarsis) larvae in the κ-carrageenan-induced rat tail thrombosis model, in comparison with that of heparin. Thrombosis was induced in Sprague–Dawley (SD) rats by intraperitoneal injection with a dose of 30 mg/kg κ-carrageenan after receiving oral pretreatment with P. brevitarsis larvae at doses of 300 or 900 mg/kg. The control group was only given physiological saline for 7 days without the administration of κ-carrageenan. The results indicate that pretreatment with P. brevitarsis larvae at 300 or 900 mg/kg not only significantly reduced the average length of the thrombus but also markedly decreased the fibrinogen levels and serum P-selectin in a dose-dependent manner (P < 0.05). However, there were no notable effects on the blood clotting times, such as prothrombin time (PT) and activated partial thromboplastin time (aPTT). Moreover, the histological analysis of tail tissues treated with P. brevitarsis larvae supported the serum biochemical findings, thereby providing evidence of enhanced blood circulation. Based on these results, it was concluded that P. brevitarsis larvae had a positive effect on preventing thrombosis in vivo through the reduction of fibrinogen and P-selectin levels, suggesting potential applications for thrombosis prevention.

Insects are the first arthropods to invade cadavers and, thus, can be used as evidence in criminal investigations. The current study aimed to investigate the possibility of breeding insect eggs in the lab that would be collected from male human cadavers kept in the mortuary refrigerators at sub-freezing temperatures for different periods. Egg specimens were collected from different human cadavers preserved from −16 to −20°C for different time intervals. All collected eggs were incubated at 25–30°C and 60%–70% and observed until hatched larvae complete their life cycle. All obtained larvae and adults were identified based on morphological characteristics. Data showed that, at selected ranges of temperature and humidity, some eggs were hatched to the first larval stage and then stopped growing, while others completed their life cycle to the adult insect stage. The obtained adult insects were identified using morphological classification and found to belong to Dermestes frischii.