Search Results (102)

Sterol Carrier Protein X (SCP-x) is an evolutionarily conserved lipid transport protein that plays important roles in sterol metabolism. In insects, cholesterol is an essential component of cellular membranes and the precursor of ecdysteroids, yet insects cannot synthesize cholesterol de novo and must obtain it from dietary sources. However, the functional role of SCP-x in cholesterol absorption and transport in insects remains poorly understood. In this study, the SCP-x gene from the migratory locust Locusta migratoria was identified and characterized using transcriptomic data from the midgut and fat body. The full-length LmSCP-x encodes a 404-amino-acid protein containing both the 3-oxoacyl-CoA thiolase domain and the sterol carrier protein-2 domain. Expression analysis revealed that LmSCP-x is predominantly expressed in the midgut and fat body, and subcellular localization experiments showed that the protein is mainly distributed in the cytoplasm. RNA interference-mediated knockdown of LmSCP-x significantly reduced cholesterol levels in the fat body and delayed nymphal development. Structural prediction using AlphaFold 3 further revealed a conserved three-dimensional structure of the SCP-2 domain, and molecular docking identified key amino acid residues involved in cholesterol binding, which were subsequently validated by bio-layer interferometry assays. Together, these results demonstrate that LmSCP-x plays a crucial role in cholesterol transport in L. migratoria and provide new insights into sterol metabolism in insects, offering potential targets for the development of novel pest management strategies. Full article

Growth, reproduction, and survival are fundamental biological priorities that animals balance by evaluating dietary cues. Cholesterol occupies a unique position among nutrients, serving both as a structural component of cellular membranes and as a precursor for steroid hormones, yet its regulation differs fundamentally across taxa. In mammals, cholesterol availability is buffered by endogenous synthesis and post-ingestive metabolic control. In contrast, insects have evolutionarily lost sterol biosynthesis and are therefore sterol auxotrophs that rely entirely on dietary sources. Here, we synthesize current understanding of cholesterol biology in Drosophila melanogaster, with a focus on sterol auxotrophy, life-stage–specific allocation, and endocrine and lifespan outcomes in a comparative framework. We highlight cholesterol not only as a metabolic substrate but also as a sensory-encoded nutrient that shapes feeding behavior. We further examine how lipophorin (Lpp)-mediated transport, Niemann–Pick type C proteins, ATP-binding cassette transporters, and the nuclear receptor DHR96 coordinate systemic sterol distribution and endocrine output in the absence of endogenous synthesis. By integrating these mechanisms across development, we illustrate how cholesterol availability governs larval growth, ecdysteroid production, adult reproduction, neural function, and lifespan through coupled endocrine and nutrient-signaling networks. This review positions cholesterol as a multifunctional signal linking sensory perception, metabolic regulation, and life-history strategy in sterol-auxotrophic insects, offering a framework for understanding how evolutionary loss of biosynthetic capacity reshapes nutrient sensing and homeostatic control. Full article

Phytoecdysteroids have garnered increasing interest due to their broad biological and pharmacological properties. The present study reports on the development and validation of a reliable liquid chromatography–mass spectrometry method for the detection and quantification of 20-hydroxyecdysone, turkesterone, and ponasterone. The optimized procedure improved ionization efficiency and chromatographic resolution through gradient elution using 0.1% formic acid in water and acetonitrile. Data acquisition in selective ion monitoring modes ensured high analytical precision, reproducibility, and sensitivity. The method demonstrated excellent linearity, accuracy, repeatability, and low detection limits, making it suitable for routine phytochemical and quality control applications. Application of the method to extracts from nutrient-rich superfoods, including kaniwa, spinach, quinoa, and asparagus, confirmed these plants as natural sources of phytoecdysteroids. Additionally, thirteen commercially available dietary supplements labeled as containing extracts of Rhaponticum carthamoides, Cyanotis arachnoidea, Ajuga turkestanica, or ecdysteroids were analyzed. Several products standardized to 80–95% ecdysterone contained substantially lower amounts than declared, with measured 20-hydroxyecdysone levels ranging from below the limit of detection to approximately 50 mg per capsule, whereas some non-standardized products exhibited moderate to high levels, reaching up to approximately 105 mg per capsule. Variability in turkesterone content was also observed among products marketed as standardized extracts. The method provides a simple, reliable, and accessible approach for the quantitative analysis of major phytoecdysteroids in complex plant matrices and dietary supplements. Its implementation may support phytochemical research, routine quality control, and anti-doping monitoring of ecdysteroid-containing products. Full article

According to a previous study, in insects, cyp307A1 plays a central role in ecdysteroid synthesis, which is a member of the cytochrome P450 family. However, the function of cyp307A1 in crustaceans remains unclear. In this study, we explored the function of Eccyp307a1 in Exopalaemon carinicauda through a series of experiments. The sequence of Eccyp307a1 encoded 529 amino acids, and the protein was found to possess typical P450 domains and heme-binding sites. The mRNA of Eccyp307a1 was expressed at a higher level during the early stages of ovary development, but was expressed less during the mature stage. Furthermore, employing eyestalk ablation and RNAi experiments, we determined that Eccyp307a1 could be regulated by neuroendocrine factors and is essential for the normal initiation of ovary development. These findings provided insights into the gene function of Eccyp307a1 in early ovary development in E. carinicauda, and our study further elucidates the molecular mechanisms of ovary development in crustaceans. Full article

The ecdysteroid receptor (EcR) plays a crucial role in insect development and metamorphosis, making it a promising target for the design of novel biorational compounds. This study investigated the cytotoxicity, as well as the EcR agonist and antagonist activities, of three synthetic molecules analogous to tebufenozide and extracts from nine plant species using the dipteran S2 cell line which originates from the insect model of the fruit fly Drosophila melanogaster. Cytotoxicity assays were performed to determine appropriate concentrations of the synthetic molecules and plant extracts for cell transfection. EcR agonist and antagonist activities were evaluated using 20-hydroxyecdysone (20E) as the control hormone. The synthetic molecules analogous to tebufenozide did not activate EcR in S2 cells. In contrast, the plant extract of Neoblechnum brasiliense, commonly known as Brazilian dwarf tree fern, exhibited significant antagonistic activity at 100 µM, reducing receptor activity by 92%, likely due to its phytosteroid content, and without inducing cytotoxic effects. These findings demonstrate that certain plant extracts, particularly N. brasiliense, act as effective EcR antagonists and may represent promising natural leads for the development of environmentally compatible biorational compounds to control economically important dipteran pests, such as fruit flies and mosquitoes. Full article

HR38 and E75 are early 20-hydroxyecdysone (20E)-responsive nuclear receptors that play important roles in insect molting and metamorphosis. Here, we cloned and characterized HvHR38 and HvE75 from Heortia vitessoides and analyzed their conserved domains and phylogenetic positions. Both genes exhibited distinct stage- and tissue-specific expression patterns closely associated with ecdysteroid-regulated developmental processes. Hormone-induction assays further demonstrated that the transcription of HvHR38 and HvE75 was strongly activated by 20E. RNA interference targeting either gene resulted in significant transcript knockdown, accompanied by incomplete molting, pupal deformities, and molting failure, ultimately leading to markedly reduced survival, with dsHvE75 causing the highest lethality. Collectively, these results suggest that HR38 and E75 function as key components of the early 20E-responsive transcriptional network involved in molting regulation, and highlight their potential as RNAi targets for species-specific and environmentally sustainable pest management. Full article

Excess adiposity is associated with increased oxidative stress and inflammation, which contribute to metabolic dysregulation. Both exercise training and bioactive plant-derived compounds have been explored as therapeutic strategies to mitigate these effects. Asparagus (Asparagus officinalis L.) root extract, rich in ecdysteroids such as 20-hydroxyecdysone (20E), exhibits potent antioxidant and anti-inflammatory activities. This randomized controlled trial investigated the combined effects of high-intensity interval training (HIIT) and asparagus root extract (ARE) supplementation on metabolic parameters, oxidative stress, inflammatory biomarkers, and white blood cell counts in overweight and obese adults. Seventy-two participants aged 18–30 years with a body mass index ≥ 23 kg/m² were randomly assigned to one of four groups: control (CON), ARE supplementation only (ARE), HIIT only (HIIT), and combined intervention (COM). The HIIT protocol comprised a modified Tabata regimen of progressive bodyweight intervals at 80–90% and 40–50% of maximal perceived exertion, performed three times per week for 12 weeks. Participants in the ARE and COM groups received a daily oral dose of ARE providing 1.71 ± 0.24 mg/kg/day of 20E. Compared with the CON group, the HIIT group showed significant reductions in total cholesterol (TC), the TC/high-density lipoprotein cholesterol (HDLC) ratio, and blood glucose levels, alongside significant increases in HDLC and superoxide dismutase (SOD) activity (all p < 0.05). The COM group demonstrated significant decreases in protein carbonyls and interleukin-6 levels and in the TC/HDLC ratio (all p < 0.05) as well as a significant increase in SOD activity (p = 0.002). The ARE group, meanwhile, exhibited significant increases in both SOD activity (p < 0.001) and malondialdehyde levels (p = 0.017). These findings suggest that combining HIIT with ARE supplementation produces synergistic improvements in oxidative and inflammatory status, whereas HIIT alone primarily enhances metabolic regulation in overweight and obese individuals. Full article

The AGC kinases constitute a large and ancient gene superfamily with origins that coincided with the appearance of multicellularity. Three AGC kinase families—protein kinase A (PKA), protein kinase G (PKG), and protein kinase C (PKC)—mediate the actions of neuropeptide hormones, biogenic amines, and other ligands on various physiological processes in metazoans. Metazoans express two PKG types. Jawed vertebrates express three PKA catalytic (C) subunits, four regulatory (R) subunits, and twelve PKCs, organized into conventional, novel delta-like, novel epsilon-like, atypical, and protein kinase N (PKN) subfamilies. By contrast, invertebrate PKA and PKC sequences are not well characterized. Consequently, limited database resources can result in misidentification or mischaracterization of proteins and can lead to misinterpretation of experimental data. A broad phylogenetic and sequence analysis of CrusTome transcriptome and GenBank databases was used to characterize 640 PKA-C sequences, 1122 PKA-R sequences, and 1844 PKC sequences distributed among the Annelida, Arthropoda, Chordata, Cnidaria, Nematoda, Mollusca, Echinodermata, Porifera, Platyhelminthes, and Tardigrada. Phylogenetic analysis and multiple sequence alignments revealed conservation of certain PKA-C, PKA-R and PKC isoforms across metazoans, as well as diversification of additional taxon-specific isoforms. Decapods expressed four PKA-C isoforms, designated PKA-C₁, -C_D1, -C_GLY1, and -C_GLY2; five PKA-R isoforms, designated PKA-RI₁, -RI_D1, -RII_GLY, and -RII_D1; and five PKC isoforms, designated PKN_D1-3, conventional cPKC_D1, novel nPKC_D1δ and nPKC_D1ε, and atypical aPKC_D1. PKA-C_GLY1, -C_GLY2, and -RII_GLY had glycine-rich N-terminal sequences that were unique to crustaceans. These data suggest lineage-specific diversification that retained the core catalytic function of each kinase, while regions outside of the kinase domain may provide specialized regulatory mechanisms and/or spatiotemporal subcellular localization in invertebrate tissues. Full article

To provide a scientific basis for pest control, this study evaluated the insecticidal activity of novaluron against the fall armyworm (Spodoptera frugiperda) and diamondback moth (Plutella xylostella). The leaf-dip method determined the toxicity of novaluron to second-instar larvae, while corn leaves and cabbage treated with sublethal (LC₁₀) and median lethal concentrations (LC₅₀) of novaluron were used to feed the larvae. Enzyme-linked immunosorbent assays (ELISA) measured the activities of detoxifying enzymes [carboxylesterase (CarE), cytochrome P450 (P450), glutathione S-transferase (GST), and acetylcholinesterase (AChE)] and ecdysteroid (Ecd) levels in the pests after 24 and 48 h of treatment. Results indicated that after 24 h, AChE was involved in diamondback moth metabolism and CarE activity was inhibited. After 48 h, P450 and GST participated in fall armyworm detoxification, whereas P450 and GST were active in diamondback moth detoxification, with other enzyme activities normalizing. Novaluron also altered Ecd levels in both pests. These results demonstrate differing detoxification mechanisms in fall armyworm and diamondback moth, likely due to their unique physiological and ecological traits, and support the potential use of novaluron in pest management strategies. Full article

Background: As a globally significant aquaculture species, elucidating the molecular mechanisms underlying the regulation of the Pacific White Shrimp (Litopenaeus vannamei) growth holds substantial scientific and industrial value. This study systematically investigates the role of the LvChia2 gene in governing growth and development through a cross-tissue metabolic network approach. Methods: RNA knockdown (RNAi)-mediated knockdown of LvChia2 significantly impaired growth performance and triggered a tissue-specific metabolic compensation mechanism. Results: This mechanism was characterized by reduced crude lipid content in muscle and adaptive modulation of lipase (LPS) activities in hepatopancreatic and intestinal tissues, suggesting inter-tissue metabolic coordination. Transcriptomic profiling identified 610 differentially expressed genes (DEGs), forming a three-dimensional regulatory network encompassing “energy metabolism, molt regulation, and nutrient utilization.” Key mechanistic insights revealed the following: (1) Enhanced mitochondrial energy transduction through the upregulation of ATP synthase subunits and NADH dehydrogenase (ND-SGDH). (2) The disruption of ecdysteroid signaling pathways via suppression of Krueppel homolog 1 (Kr-h1). (3) The coordinated regulation of nitrogen metabolism through the downregulation of glutamine synthetase and secretory phospholipase A2. These molecular adaptations, coupled with tissue-specific oxidative stress responses, reflect an integrated physiological strategy for environmental adaptation. Conclusions: Notably, this study provides the first evidence in crustaceans of chitinase-mediated growth regulation through cross-tissue metabolic interactions and identifies six core functional genes (ATP5L, ATP5G, ND-SGDH, Kr-h1, GS, sPLA2) as potential targets for molecular breeding. A novel “gut-hepatopancreas axis” energy compensation mechanism is proposed, offering insights into resource allocation during metabolic stress. These findings advance our understanding of crustacean growth regulation and establish a theoretical foundation for precision aquaculture strategies, including genome editing and multi-trait genomic selection. Full article

Phytoecdysteroids represent a class of naturally occurring substances known for their diverse biological functions, particularly their strong ability to stimulate protein anabolism. In this study, a computational machine learning-driven quantitative structure–activity relationship (QSAR) approach was applied to analyze the anabolic potential of 23 ecdysteroid compounds. The ML-based QSAR modeling was conducted using a combined approach that integrates Genetic Algorithm-based feature selection with Multiple Linear Regression Analysis (GA-MLRA). Additionally, structure optimization by semi-empirical quantum-chemical method was employed to determine the most stable molecular conformations and to calculate an additional set of structural and electronic descriptors. The most effective QSAR models for describing the anabolic activity of the investigated ecdysteroids were developed and validated. The proposed best model demonstrates both strong statistical relevance and high predictive performance. The predictive performance of the resulting models was confirmed by an external test set based on R²_test values, which were within the range of 0.89 to 0.97. Full article

Silk yield enhancement in sericulture has plateaued. Sodium butyrate (NaB) is known to improve production performance in livestock and poultry, yet its effects on silkworm silk yield remain uncharacterized. Here, we evaluated the impact of dietary NaB supplementation on silkworm growth, silk gland development, and cocoon output. Mulberry leaves were immersed in NaB solutions at concentrations of 0, 2.5, 5, 10, 20, 40, or 80 mM, and subsequently provided as feed to third- to fifth-instar larvae. Among these, 10 mM NaB treatment most effectively promoted larval and pupal weight gain and increased food intake. Phenotypic and economic trait analyses revealed that 10 mM NaB treatment significantly enlarged the silk gland and boosted overall silk yield. Mechanistically, NaB enhanced body growth by increasing feeding intake and influencing the juvenile hormone and ecdysteroid signaling pathways; moreover, it promoted DNA replication in silk gland cells, thereby influencing silk gland development. Taken together, our findings demonstrate that dietary supplementation with an appropriate concentration of NaB concurrently enhances body growth and silk gland development, leading to higher silk production, and underscore the potential of short-chain fatty acid salts in advancing sericulture. Full article

The pupal stage in necrophagous flies represents the longest and least morphologically distinct phase of development, posing a persistent challenge for accurately estimating postmortem intervals (PMI) in forensic investigations. Here, we present a novel molecular approach to pupal age estimation in Sarcophaga peregrina, a forensically important species, by profiling microRNA (miRNA) expression dynamics. High-throughput sequencing across early, mid, and late pupal stages identified 191 known miRNAs, of which nine exhibited distinct monotonic temporal trends. Six miRNAs (miR-210-3p, miR-285, miR-927-5p, miR-956-3p, miR-92b, and miR-275-5p) were validated by qRT-PCR and demonstrated consistent time-dependent expression patterns. Polynomial regression models revealed a strong correlation between miRNA abundance and developmental age (R² = 0.88–0.99). Functional enrichment analyses of predicted miRNA targets highlighted their roles in key regulatory pathways, including ecdysteroid signaling, hypoxia response, autophagy, and energy metabolism. This study establishes, for the first time, a robust miRNA-based framework for estimating pupal age in forensic entomology, underscoring the potential of miRNAs as temporally precise biomarkers for PMI estimation. Full article

Sesquiterpenoid hormones are widely present in arthropods and play crucial roles in growth, molting and reproduction. Methyl farnesoate (MF) functions similarly to juvenile hormone (JH) in crustaceans, playing a broad regulatory role in their growth and development. However, compared to insects, systematic studies on the mechanisms of sesquiterpenoid hormones in crustaceans are still lacking. Neocaridina denticulata, a small freshwater shrimp known for its fast growth, high reproductive capacity and ease of maintenance, is an ideal model organism for crustacean research. To investigate the effects of MF on the growth and development of juvenile N. denticulata, MF feeding experiments were conducted and the changes at the phenotypic and molecular levels were examined. In this experiment, the basal diet was used as a control, with 40 μg/kg, 4 μg/kg and 0.4 μg/kg of MF added to the feed. The MF-enriched diets were fed to juvenile N. denticulata and the growth in body length was measured every 10 days. After 40 days of feeding experiment, the activities of amylase (AMS), lipase (LPS), trypsin (Try), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) were assessed, and transcriptome analysis was performed. We found that MF showed an initial inhibitory effect on body length (day 30), but by day 40, the low-concentration group exhibited significantly enhanced growth compared to the control, indicating a dose- and time-dependent effect. Activities of AMS, LPS, Try and SOD generally decreased, whereas MDA levels and GSH-PX activity increased after 40 days of MF exposure. Moreover, transcriptomic analysis revealed that MF regulated various biological processes including growth, metabolism and immune responses. High concentration group appeared to restrict growth via modulation of exoskeleton-related and cellular stress genes. Medium concentration group enhanced growth by optimizing metabolic and signaling pathways. Low concentration group preferentially up-regulated genes related to muscle function, potentially supporting locomotion and competitive ability. This study provides new insights into the regulatory mechanism of sesquiterpenoid hormones in crustaceans and their potential applications in aquaculture in the future. Full article

20-hydroxyecdysone (20E) is essential for insect development and diapause. Ecdysone receptor (EcR) and ultraspiracle (USP) proteins are crucial regulators of 20E signaling. To explore their potential roles in the development of Sitodiplosis mosellana, a major wheat pest that undergoes obligatory diapause as a larva, one SmEcR and two SmUSPs (SmUSP-A and SmUSP-B) from this species were isolated and characterized. The deduced SmEcR and SmUSP-A/B proteins contained a conserved DNA-binding domain with two zinc finger motifs that bind to specific DNA sequences. Expression of SmEcR and the SmUSPs was developmentally controlled, as was 20E induction. Their transcription levels increased as the larvae entered pre-diapause, followed by downregulation during diapause and upregulation during the shift to post-diapause quiescence, which is highly consistent with ecdysteroid titers in this species. Topical application of 20E to diapausing larvae also elicited a dose-dependent expression of the three genes. Expression of SmEcR and SmUSPs decreased markedly during the pre-pupal stage and was higher in adult females compared to males. These findings suggested that 20E-induced expression of SmEcR and SmUSPs has key roles in diapause initiation and maintenance, post-diapause quiescence, and adult reproduction, while the larval–pupal transformation may be associated with a decrease in their expression levels. Full article