Archives of Insect Biochemistry and Physiology最新文献

Pesticides have adverse impacts not only on targeted pests but also on the surrounding environment and other species. Therefore, it is important to develop biopesticides. In this study, insecticidal activity against Lasioderma serricorne (F.) larval, pupal, and adult stages (Coleoptera: Anobiidae) was investigated using the essential oil (EO) of Juniperus communis L. berries. L. serricorne individuals were exposed to J. communis EO at varied concentrations (17.2 mg/L, 25.8 mg/L, 34.4 mg/L, 43 mg/L, 51.6 mg/L and 60.2 mg/L) for 24, 48, and 72 h. At the end of the experimental period, mortality, LC₅₀, LC₉₀, and LC₉₉ values for the insects were determined. In addition, antioxidant enzyme activities [Superoxide Dismutase (SOD), Glutathione-S-transferase (GST), Catalase (CAT), Glutathione Peroxidase (GPx), Glutathione reductase (GR)], acetylcholinesterase (AChE) activity, 8-hydroxy-2-deoxyguanosine (8-OHdG), reactive oxygene species (ROS), malondialdehyde (MDA)and DNA fragmentation levels were measured to determine the presence of oxidative stress. At the end of the examination, it was concluded that the larval stage of L. serricorne was the most affected by EO, while the pupal stage was the least affected. The mortality rate of L. serricorne increased with increasing the time and the concentration of exposure to EO. Antioxidant enzyme activity and 8-OHdG levels decreased, but MDA levels and DNA fragmentation increased. In light of the data collected, it was determined that the EO of J. communis has a key function in the control of the insect because it induces oxidative damage on L. serricorne. This study is the first to explore the effect of J. communis on L. serricorne.

Field-evolved indoxacarb resistance in many kinds of pests poses growing threats to pest management. Previous studies revealed that inward rectifier potassium channels (PxKirs) in Plutella xylostella are implicated in resistance mechanisms, but their functional roles remain uncharacterized. Here, we investigated a field-derived strain (RR = 129.58) exhibiting significant downregulation of PxKir1, PxKir2, PxKir3A/B, and PxKir4 under LC₅₀ indoxacarb exposure. Tissue-specific profiling revealed PxKir1 dominance in the head, while other isoforms enrichment in Malpighian tubules and midgut. RNAi-mediated PxKir1 suppression unexpectedly increased resistance by 56.3%, demonstrating its counterintuitive regulatory role. Mechanistically, silencing reduced GST (9.4%) and P450 (31.8%) activities but elevated CarE activity (1.7-fold), accompanied by downregulation of PxGSTO4, PxNa_v, and PxCYP6BF1v2. Phenotypic analyses revealed multigenerational costs: prolonged pupal duration (4.7%), reduced pupal weight (17.6%) and length (3.9%), and shortened male longevity (13.8%) despite elevated eclosion rates (37.4%). Our findings establish PxKir1 as a dual-function modulator governing indoxacarb resistance through (1) coordinated detoxification enzyme regulation and (2) life-history trade-offs favoring survival over developmental fitness. This study provides a comprehensive understanding of the role of PxKir1 in indoxacarb resistance and highlights the physiological, biochemical, and biological consequences of its silencing. The findings offer valuable insights for developing resistance management strategies, screening novel insecticidal agents, and optimizing the application of chemical insecticides to mitigate resistance development in P. xylostella populations.

In Tribolium castaneum, juvenile hormone (JH) signal, through Methoprene-tolerant (Met)/Taiman (Tai) heterodimer, regulates vitellogenesis. Considering that Coleoptera is by far the largest animal taxon, whether JH pathway controls vitellogenesis remains to be clarified in other Coleopteran species. In the current paper, temporal expression determination revealed that JH signal is triggered in the young female adults in two Henosepilachna species, consistent with active oogenesis and vitellogenesis in these beetles. Aided by RNA interference (RNAi), we knocked down a JH biosynthesis gene Hvpjhamt and a JH receptor gene HvpMet in Henosepilachna vigintioctopunctata, and two JH receptor genes HvmMet and HvmTai in H. vigintioctomaculata. The knockdown significantly inhibited JH signal. As a result, the oviposition is greatly reduced and the vitellogenesis is significantly delayed in the two Henosepilachna species. Little yolk substances were seen in the oocytes in the Hvpjhamt and HvpMet RNAi ovaries, in contrast to larger amount of yolk granules in the normal oocytes in H. vigintioctopunctata. Correspondingly, the transcript levels of Vg in the fat bodies and of VgR in the ovaries were significantly lowered in the Hvpjhamt, HvpMet, HvmMet, and HvmTai RNAi samples. Therefore, our findings suggest that JH signal, mediating through Met/Tai complex, plays a key role in Vg synthesis and uptake in the two Coleopteran species.

Acid soaking with hydrochloric acid (HCl) is a common method used to prevent or break diapause in silkworm eggs and has been widely applied in production. However, its underlying mechanism remains to be explored. Few studies have reported on the metabolism of mono- or disaccharides, and the differential expression patterns of genes and proteins related to the phosphatidyl inositol 3-kinase (PI3K/)Akt signaling pathway across the stages of silkworm diapause eggs, non-diapause eggs, instant acid-soaked eggs, and red bean color acid-soaked (RBCAS) eggs. In this study, eggs from the silkworm 932 strain at different stages were used to explore the content of several saccharides and analyze the expression profiles of 4 diapause-related genes in the PI3K/Akt signaling pathway via qPCR. Results revealed that in addition to monosaccharides such as glucose and fructose, the contents of polysaccharides, maltose, trehalose, and sorbitol varied significantly at different stages and states of the eggs. The expression profiles of the genes were low but increased in instant acid-soaked and RBCAS eggs before hatching. Western blot analysis results showed that the ratio of phosphorylated Akt in diapause and RBCAS eggs was equivalent but significantly higher in RBCAS eggs after activation of the PI3K/Akt signaling pathway. These findings revealed that saccharides are basic energy sources, and that the activation of the PI3K/Akt signaling pathway plays an important role during acid soaking to prevent or break diapause in eggs.

Sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) plays a critical role in maintaining intracellular Ca²⁺ homeostasis by transporting excess Ca²⁺ into the endoplasmic reticulum (ER) calcium reservoir. Calcium is essential for regulating key biological processes in Bombyx mori, including development, metamorphosis, and reproduction. To explore the role of BmSERCA in the proliferation of the B. mori ovary cell line (BmN), intracellular Ca²⁺ levels were measured following BmSERCA interference. At 48 h post-interference, intracellular Ca²⁺ levels increased significantly by 1.38 times. Moreover, transcript levels of genes involved in cell proliferation and division exhibited notable changes. Phenotypic assessments further demonstrated that BmSERCA interference significantly accelerated the proliferation and migration of BmN cells, with a marked increase in EdU-positive cells. Additionally, flow cytometry analysis revealed that BmSERCA interference notably affected the cell cycle by inducing G2/M phase accumulation and elevating the expression of G2/M phase regulators, including BmCyclinB and BmCDK1. Collectively, these findings suggested that BmSERCA interference disrupted intracellular Ca²⁺ homeostasis, thereby promoting BmN cell proliferation. This study provided a valuable foundation for understanding the role of BmSERCA in BmN cell proliferation.

The growth and development of insects are mainly governed by juvenile hormone (JH) and molting hormone, which play essential roles in metamorphosis, reproductive control, and signal transduction. However, it remains uncertain whether E74, a crucial transcription factor within the 20- hydroxyecdysone (20E) signaling pathway, is involved in regulating chitin biosynthesis in Lasioderma serricorne. In this study, the E74 gene was identified in L. serricorne, a damaging and prevalent pest of stored products. The E74 gene features an open reading frame of 1, 266 bp that encodes a protein of 421 amino acids, characterized by a typical Ets domain structure. Phylogenetic analysis indicated that E74 is most closely related to Onthophagus taurus. Analysis of temporal expression patterns revealed that E74 is expressed throughout all developmental stages of L. serricorne, with peak expression occurring during the prepupal stage. Tissue-specific expression studies showed high levels of E74 in the epidermis and head. RNA interference (RNAi) assays demonstrated that silencing E74 led to a mortality rate of 68.33%. Experiments involving hormone treatment confirmed that E74 expression is upregulated by 20E and downregulated by JH analog methoprene. Furthermore, the knockdown of E74 significantly decreased the expression of genes associated with the chitin biosynthesis pathway, which was corroborated by a notable reduction in chitin levels following E74 knockdown. In conclusion, this study established that E74 is not only vital for the growth and development of L. serricorne but also plays a role in regulating chitin biosynthesis. This study enhances the understanding of E74's functional role across various species and offers insights for identifying potential targets for pest control.

Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are essential for host-seeking behaviors in herbivorous and predatory insects. However, limited studies have examined differences in the OBP and CSP profiles between herbivores and predators. Mirid bugs, which ancestrally were predatory, provide an ideal model to investigate these differences because some of mirid species have evolved to develop herbivorous capacities. In this study, we compared compared OBP and CSP profiles among transcriptome analysis of one zoophytophagous and four phytozoophagous mirid bugs, identifying a total of 146 OBPs and 69 CSPs. The number of OBPs was similar between phytozoophagous (26 in Adelphocoris fasciaticollis, 29 in Adelphocoris lineolatus, 28 in Apolygus lucorum, and 32 in Adelphocoris suturalis) and zoophytophagous (31 in Nesidiocoris tenuis) species. However, the zoophytophagous specie had more CSPs than the phytozoophagous species. Phylogenetic analysis revealed two types of OBPs in mirid bugs, with classic OBPs being more abundant than plus-C OBPs. Transcriptome revealed that the number of OBPs with high expressions was higher in the phytozoophagous species (18) than in the zoophytophagous species (14). By contrast, more CSPs (10) exhibited high expressions in the zoophytophagous mirid bug compared with those in the phytozoophagous species (≤ 7). These results suggest that differences in the number and expression levels of OBPs and CSPs between zoophytophagous and phytozoophagous mirid bugs affect host-selection processes. In conclusion, the findings provide a basis for developing novel pest management strategies, including the use of natural enemies or behavioral regulation of mirid bugs through OBP and CSP gene manipulation.

The omega glutathione S-transferases (GSTOs) are a class of cytosolic GSTs and play important roles in antioxidant defense in insects. However, the functions of some GSTOs remain unclear. Here, we performed functional analysis of a GSTO2 in Tribolium castaneum (TcGSTO2). Sequence alignment indicated that this gene was conserved among insects. During development, TcGSTO2 was highly expressed in the late stage of larva and pupa and the hemolymph, fat body, malpighian tubules of late larva. After treatment with various insecticides such as DDV, KBV, phoxim, and lambda-cyhalothrin, the expression level of TcGSTO2 was significantly increased, and knockdown of TcGSTO2 reduced the resistance to the insecticides. Exposure to various types of oxidative stress, including heat, cold, UV, and pathogenic microbes, largely induced TcGSTO2 expression, and overexpression of TcGSTO2 in E. coli increased the resistance to oxidative stress induced by paraquat and cumene hydroperoxide. Our study showed that TcGSTO2 participated in the cellular detoxification and antioxidant defense, deepening our understanding of the functional diversity of GSTOs in insects.

Argonaute (Ago) proteins are integral components of the RNA-induced silencing complex (RISC), regulate gene expression through RNAi, and are essential for embryogenesis and cellular morphogenesis in insects. However, today, little is known about their role in the molting development of insects. In this study, we have used the white-backed planthopper (Sogatella furcifera) as an important model and pest in agriculture, and we characterized and investigated the role of Ago-1 and Ago-2. In essence, the respective cDNA sequences of SfAgo1 and SfAgo2 contained 2823 and 3446 bp, and the respective encoded amino acids were 940 and 829. RT-qPCR revealed that Ago1 and Ago2 were expressed in all life stages as the nymphs that undergo molting, also in all tissues as the integument that is involved in new cuticle synthesis and chitin metabolism. Following RNAi, the lethal phenotypes showed molting failure, and typically, the expression levels of the chitin metabolic pathway genes and Dicer were significantly reduced. Similarly, transcriptome analysis revealed considerable enrichment of the GO terms structural constituent of cuticle, chitin catabolic progress, chitin binding, amino sugar and nucleotide sugar metabolism, and aminoglycan catabolic process upon RNAi of Ago1 and Ago2. Altogether, our findings indicate that Ago-1 and Ago-2 play a pivotal role in molting and new cuticle formation of insects. The data are discussed in relation to potential mechanisms and the use of RNAi in pest insect control.