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Keywords = ecdysone receptors

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14 pages, 2957 KiB  
Article
Effects of the Ecdysone Receptor on the Regulation of Reproduction in Coccinella septempunctata
by Ying Cheng, Yuhang Zhou and Cao Li
Insects 2025, 16(6), 643; https://doi.org/10.3390/insects16060643 - 19 Jun 2025
Viewed by 551
Abstract
The effects of the gene encoding the ecdysone receptor (EcR) on the reproduction of the ladybug Coccinella septempunctata was evaluated. EcR transcription was measured by quantitative real-time PCR in ladybug adults reared on artificial diets with and without 20-hydroxyecdysone (20E). EcR [...] Read more.
The effects of the gene encoding the ecdysone receptor (EcR) on the reproduction of the ladybug Coccinella septempunctata was evaluated. EcR transcription was measured by quantitative real-time PCR in ladybug adults reared on artificial diets with and without 20-hydroxyecdysone (20E). EcR expression levels in 5 d old male and female ladybugs supplied with the 20E-amended artificial diet were lower than expression levels in ladybugs reared on an artificial diet lacking 20E. However, EcR expression levels in 10 d old ladybugs supplied with the 20E artificial diet were higher than those lacking 20E supplementation. The regulatory effects of EcR were studied in female and male ladybugs by RNA interference. EcR expression in female ladybugs injected with EcR-dsRNA was significantly downregulated after 5 d but remained unaffected in 10 d old females. EcR expression levels in males microinjected with EcR-dsRNA were significantly lower at 5 and 10 d after microinjection than GFP-dsRNA-treated males. The ovary volume in females injected with EcR-dsRNA at 5 d was smaller than females microinjected with GFP-dsRNA, but volumes at 10 d were larger than in GFP-dsRNA-treated females. The testes of males injected with EcR-dsRNA were larger than those injected with GFP-dsRNA at 5 d but the testes at 10 d after injection with EcR-dsRNA were smaller than those injected with GFP-dsRNA. When females were microinjected with EcR-dsRNA and mated with noninjected males, egg production decreased by 34.80% for 20 days. When males were microinjected with EcR-dsRNA and mated with noninjected females, egg production decreased by 30.38% for 20 days. Injection of female and male ladybugs with EcR-dsRNA had no significant effect on egg hatching rates. Our results show that EcR plays an important role in the development of reproductive organs and egg development in C. septempunctata. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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14 pages, 1599 KiB  
Article
Chronic Low-Dose Phoxim Exposure Impairs Silk Production in Bombyx mori L. (Lepidoptera: Bombycidae) by Disrupting Juvenile Hormone Signaling-Mediated Fibroin Synthesis
by Xinyi Xie, Jiayin Hou, Meng Li, Zhiyu Liu, Mengai He, Chenxi Li, Xiaohua Du and Liezhong Chen
Toxics 2025, 13(6), 427; https://doi.org/10.3390/toxics13060427 - 23 May 2025
Viewed by 332
Abstract
Phoxim is a pesticide extensively applied in mulberry fields, and residues may persist on leaves even after the recommended pre-harvest interval. However, the potential risks of these residues to Bombyx mori L. (Lepidoptera: Bombycidae) have long been overlooked. The results demonstrated that chronic [...] Read more.
Phoxim is a pesticide extensively applied in mulberry fields, and residues may persist on leaves even after the recommended pre-harvest interval. However, the potential risks of these residues to Bombyx mori L. (Lepidoptera: Bombycidae) have long been overlooked. The results demonstrated that chronic low-dose exposure from the second to fifth instars significantly impaired silkworm development and silk production. Specifically, larvae in the 0.316 μg/mL treatment group (1/2 LC50) exhibited a significant reduction in body weight, while the cocoon shell ratio was significantly decreased in both the 0.079 μg/mL (1/8 LC50) and 1/2 LC50 groups. Cocoon deformities were observed in the 0.032 μg/mL (1/20 LC50), 1/8 LC50, and 1/2 LC50 groups. Histopathological analysis revealed silk gland damage in the treatment groups, with severity increasing with higher phoxim concentrations. Biochemical analyses indicated elevated malondialdehyde (MDA) levels accompanied by increased superoxide dismutase (SOD) and peroxidase (POD) activities. Notably, phoxim exposure selectively reduced juvenile hormone (JH) titers without affecting ecdysone titers. JH-regulated genes including the receptors Met1 and Met2, and transcription factors Kr-h1 and Dimm were downregulated, accompanied by suppressed expression of the fibroin synthesis gene Fib-H. These results collectively indicate that chronic low-concentration phoxim exposure disrupts endocrine regulation, damages silk gland integrity, and ultimately reduces silk production in silkworm. Full article
(This article belongs to the Special Issue Impacts of Agrochemicals on Insects and Soil Organisms)
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15 pages, 2156 KiB  
Article
Molecular Characterization and Expression of the Ecdysone Receptor and Ultraspiracle Genes in the Wheat Blossom Midge, Sitodiplosis mosellana
by Qitong Huang, Linqing Meng, Yuhan Liu, Keyan Zhu-Salzman and Weining Cheng
Insects 2025, 16(5), 537; https://doi.org/10.3390/insects16050537 - 19 May 2025
Viewed by 668
Abstract
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 [...] Read more.
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
(This article belongs to the Section Insect Molecular Biology and Genomics)
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13 pages, 2179 KiB  
Article
Epigenetic and Gene Expression Responses of Daphnia magna to Polyethylene and Polystyrene Microplastics
by Hyungjoon Im, Jieun Lee, Jeong-Eun Oh, Jinyoung Song and Sanghyun Jeong
Molecules 2025, 30(7), 1608; https://doi.org/10.3390/molecules30071608 - 3 Apr 2025
Cited by 2 | Viewed by 1062
Abstract
Microplastics (MPs), ubiquitous environmental pollutants, pose substantial threats to aquatic ecosystems and organisms, including the model species Daphnia magna. This study examined the effects of polyethylene (PE) and polystyrene (PS) MPs on D. magna, focusing on their ingestion, epigenetic alterations, and [...] Read more.
Microplastics (MPs), ubiquitous environmental pollutants, pose substantial threats to aquatic ecosystems and organisms, including the model species Daphnia magna. This study examined the effects of polyethylene (PE) and polystyrene (PS) MPs on D. magna, focusing on their ingestion, epigenetic alterations, and transcriptional responses. Exposure experiments revealed a concentration-dependent accumulation of MPs, with PS particles showing higher ingestion rates due to their higher density and propensity for aggregation. Epigenetic analyses demonstrated that exposure to PE MPs significantly reduced the global DNA methylation (5-mC) of Daphnia magna, suggesting hypomethylation as a potential stress response. Conversely, the DNA hydroxymethylation (5-hmC) of Daphnia magna displayed variability under PS exposure. Transcriptional analysis identified a marked downregulation of Vitellogenin 1 (v1) and upregulation of Ecdysone Receptor B (ecr-b), highlighting the occurrence of stress-related and adaptive molecular responses. These findings enhance our understanding of the molecular and epigenetic effects of MPs on aquatic organisms, offering critical insights for the development of effective environmental management and conservation strategies in the face of escalating MP pollution. Full article
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14 pages, 25858 KiB  
Article
Juvenile Hormone and Ecdysteroids Facilitate the Adult Reproduction Through the Methoprene-Tolerant Gene and Ecdysone Receptor Gene in the Female Spodoptera frugiperda
by Yan Zhang, Kui-Ting Ding, Nian-Wan Yang, Zhi-Chuang Lv, Zhen-Ying Wang, Yong-Jun Zhang, Wan-Xue Liu and Jian-Yang Guo
Int. J. Mol. Sci. 2025, 26(5), 1914; https://doi.org/10.3390/ijms26051914 - 23 Feb 2025
Cited by 2 | Viewed by 907
Abstract
Insects, as the most diverse and numerous group in the animal kingdom, are at least partly dependent on the reproduction process, which is strictly regulated by the ‘classic’ insect hormones: juvenile hormone (JH), and 20-hydroxyecdysone (20E). However, the regulatory mechanism governing the reproduction [...] Read more.
Insects, as the most diverse and numerous group in the animal kingdom, are at least partly dependent on the reproduction process, which is strictly regulated by the ‘classic’ insect hormones: juvenile hormone (JH), and 20-hydroxyecdysone (20E). However, the regulatory mechanism governing the reproduction of JH and 20E in Spodoptera frugiperda remains unclear. In this study, ovarian development and ovulation in female S. frugiperda were assessed through dissection of the ovaries following treatment with JH analog (JHA) and 20E. Moreover, the expression patterns of the JH-signal and 20E-signal-related genes were determined by quantitative PCR (qPCR), and RNA interference (RNAi) was used to investigate the role of JH and 20E-induced genes. Ovarian development was observed by microdissection, and JH and 20E titers were determined by ELISA. Kr-h1, Vg, and USP expression were determined by qPCR. Dissection and qPCR results showed that JHA and 20E promoted ovarian development, egg maturation, and egg laying by upregulating Methoprene-Tolerant (Met) and Ecdysone Receptor (EcR)expression. Additionally, the RNAi results showed that the injection of dsMet and dsEcR markedly delayed ovarian development, inhibited egg maturation, and halted egg production. Knockdown of Met and EcR significantly reduced JH and 20E content and inhibited the transcription of Kr-h1 and USP. These results indicate that JH and 20E facilitate adult reproduction through the methoprene-tolerant gene and ecdysone receptor gene in female S. frugiperda. Full article
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10 pages, 6749 KiB  
Article
20-Hydroxyecdysone Mediates Reproductive Diapause in Galeruca daurica via Ecdysone Receptor EcR and Nuclear Hormone Receptor HR3
by Ling Li, Zhihan Yao, Baoping Pang and Yanyan Li
Int. J. Mol. Sci. 2024, 25(23), 12976; https://doi.org/10.3390/ijms252312976 - 3 Dec 2024
Viewed by 989
Abstract
20-hydroxyecdysone (20E) signaling plays an important role in regulating insect growth, development, and reproduction. However, the effect of 20E on reproductive diapause and its regulatory mechanisms have not been fully understood. Galeruca daurica is a new pest in the Inner Mongolia grasslands, and [...] Read more.
20-hydroxyecdysone (20E) signaling plays an important role in regulating insect growth, development, and reproduction. However, the effect of 20E on reproductive diapause and its regulatory mechanisms have not been fully understood. Galeruca daurica is a new pest in the Inner Mongolia grasslands, and it aestivates in an obligatory reproductive diapause form. In this study, the complete open reading frame (ORF) sequence of the ecdysone receptor (EcR) was cloned from G. daurica. Application of 20E promoted the expression of EcR, nuclear hormone receptor (HR3), and vitellogenin (Vg), whereas it reduced the expression of fatty acid synthase (FAS) and lipid content, leading to delayed diapause entry in female adults. Silencing EcR or HR3 by RNAi increased the expression of FAS and lipid content, whereas it reduced the expression of Vg, inducing reproductive diapause. These results indicate that 20E may mediate reproductive diapause via a conserved EcR/HR3 cascade in G. daurica. Full article
(This article belongs to the Section Molecular Biology)
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15 pages, 5132 KiB  
Article
Methoprene-Tolerant (Met) Acts as Methyl Farnesoate Receptor to Regulate Larva Metamorphosis in Mud Crab, Scylla paramamosain
by Ming Zhao, Wei Wang, Xin Jin, Zhiqiang Liu, Minghao Luo, Yin Fu, Tianyong Zhan, Keyi Ma, Fengying Zhang and Lingbo Ma
Int. J. Mol. Sci. 2024, 25(23), 12746; https://doi.org/10.3390/ijms252312746 - 27 Nov 2024
Cited by 1 | Viewed by 1130
Abstract
The conserved role of juvenile hormone (JH) signals in preventing larvae from precocious metamorphosis has been confirmed in insects. Crustaceans have different metamorphosis types from insects; we previously proved that methyl farnesoate (MF) can prohibit larvae metamorphosis in mud crabs, but the molecular [...] Read more.
The conserved role of juvenile hormone (JH) signals in preventing larvae from precocious metamorphosis has been confirmed in insects. Crustaceans have different metamorphosis types from insects; we previously proved that methyl farnesoate (MF) can prohibit larvae metamorphosis in mud crabs, but the molecular signal of this process still needs to be elucidated. In this study, methoprene-tolerant (Met) of Scylla paramamosain was obtained and characterized, which we named Sp-Met. Sp-Met contains a 3360 bp ORF that encodes 1119 amino acids; the predicted protein sequences of Sp-Met include one bHLH, two PAS domains, one PAC domain, and several long unusual Gln repeats at the C-terminal. AlphaFold2 was used to predict the 3D structure of Sp-Met and the JH binding domain of Met. Furthermore, the binding properties between Sp-Met and MF were analyzed using CD-DOCK2, revealing a putative high affinity between the receptor and ligand. In silico site-directed mutagenesis suggested that insect Mets may have evolved to exhibit a higher affinity for both MF or JH III compared to the Mets of crustaceans. In addition, we found that the expression of Sp-Met was significantly higher in female reproductive tissues than in males but lower in most of the other examined tissues. During larval development, the expression variation in Sp-Met and Sp-Kr-h1 was consistent with the immersion effect of MF. The most interesting finding is that knockdown of Sp-Met blocked the inhibitory effect of MF on metamorphosis in the fifth zoea stage and induced pre-metamorphosis phenotypes in the fourth zoea stage. The knockdown of Sp-Met significantly reduced the expression of Sp-Kr-h1 and two ecdysone signaling genes, Sp-EcR and Sp-E93. However, only the reduction in Sp-Kr-h1 could be rescued by MF treatment. In summary, this study provides the first evidence that MF inhibits crustacean larval metamorphosis through Met and that the MF-Met→Kr-h1 signal pathway is conserved in mud crabs. Additionally, the crosstalk between MF and ecdysteroid signaling may have evolved differently in mud crabs compared to insects. Full article
(This article belongs to the Section Molecular Endocrinology and Metabolism)
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17 pages, 2100 KiB  
Article
Effects of Different Levels of Antarctic Krill Oil on the Ovarian Development of Macrobrachium rosenbergii
by Xiaochuan Zheng, Jie Yang, Xin Liu, Cunxin Sun, Qunlan Zhou, Aimin Wang, Jianming Chen and Bo Liu
Animals 2024, 14(22), 3313; https://doi.org/10.3390/ani14223313 - 18 Nov 2024
Cited by 1 | Viewed by 1361
Abstract
Antarctic krill oil has been proven to be able to promote the ovarian development of crustaceans, but its optimal application dose and potential regulatory mechanism in Macrobrachium rosenbergii are still unclear. In this study, five isonitrogenous and isolipidic diets with gradient additions of [...] Read more.
Antarctic krill oil has been proven to be able to promote the ovarian development of crustaceans, but its optimal application dose and potential regulatory mechanism in Macrobrachium rosenbergii are still unclear. In this study, five isonitrogenous and isolipidic diets with gradient additions of Antarctic krill oil (0%, 1.5%, 3%, 4.5%, and 6%) were served exposed to 8 weeks of feeding. The results show that 3–4.5% Antarctic krill oil supplementation significantly increases the weight gain rate and specific growth rate of M. rosenbergii (p < 0.05). In addition, 3–4.5% Antarctic krill oil supplementation significantly increased the content of hemolymph vitellogenin (VTG) and the levels of reproductive hormones, including methyl farnesoate (MF), estradiol (E2), and progesterone (P4) (p < 0.05). The differences in ovarian index, oocyte volume, yolk granule deposition in oocytes, and the transcription levels of VTG genes in hepatopancreas and ovarian tissues demonstrated that the addition of Antarctic krill oil significantly promoted ovarian development and vitellogenesis, especially at the 4.5% addition level. In terms of molecular signaling, this study confirms that the retinol metabolic signaling pathway, MF signaling pathway, steroid hormone signaling pathway, and ecdysone signaling pathway, along with their specific molecules, such as Farnesoic acid-O-methyltransferase (FAMeT), retinoid x receptor (RXR), ecdysone receptor (EcR), and estrogen-related receptor (ERR), are involved in the regulation of the ovarian development of M. rosenbergii by adding Antarctic krill oil at appropriate doses. The findings indicate that the supplementation of 4.5% Antarctic krill oil in the diet is optimal for stimulating the secretion of reproductive hormones in female M. rosenbergii, thereby promoting vitellogenesis and ovarian development. Full article
(This article belongs to the Special Issue Advances in Aquaculture Nutrition for Sustainable Health Management)
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19 pages, 2419 KiB  
Article
Arginine Promoted Ovarian Development in Pacific White Shrimp Litopenaeus vannamei via the NO-sGC-cGMP and TORC1 Signaling Pathways
by Xin Zhang, Yanan Yin, Haitao Fan, Qicun Zhou and Lefei Jiao
Animals 2024, 14(13), 1986; https://doi.org/10.3390/ani14131986 - 5 Jul 2024
Cited by 2 | Viewed by 1462
Abstract
This study aimed to evaluate the effects of arginine (0.5%, 1%, 1.5%, 2%, and 2.5% arginine supplementation levels were selected) on the ovarian development of Pacific white shrimp (Litopenaeus vannamei). The analyzed arginine supplementation levels in each diet were 2.90%, 3.58%, [...] Read more.
This study aimed to evaluate the effects of arginine (0.5%, 1%, 1.5%, 2%, and 2.5% arginine supplementation levels were selected) on the ovarian development of Pacific white shrimp (Litopenaeus vannamei). The analyzed arginine supplementation levels in each diet were 2.90%, 3.58%, 4.08%, 4.53%, 5.04%, and 5.55%, respectively. A total of 540 shrimp (an initial weight of approximately 14 g) with good vitality were randomly distributed into six treatments, each of which had three tanks (300 L in volume filled with 200 L of water), with 30 shrimp per duplicate. Shrimp were fed three times a day (6:00 a.m., 11:00 a.m., and 6:00 p.m.). The results showed that after the 12-week raring cycle, shrimp fed with 4.08% and 4.53% Arg achieved better ovary development, which was identified by ovarian stage statistics, ovarian morphology observation, serum hormone levels (methylfarneside (MF); 5-hydroxytryptamine (5-HT); estradiol (E2); and gonadotropin-releasing hormone (GnRH)), gene expression (DNA meiotic recombinase 1 (dmc1), proliferating cell nuclear antigen (pcna), drosophila steroid hormone 1 (cyp18a), retinoid X receptor (rxra), and ecdysone receptor (ecr)). Further in-depth analysis showed that 4.08% and 4.53% Arg supplementation increased the concentration of vitellogenin in hepatopancreas and serum (p < 0.05) and upregulated the expression level of hepatopancreatic vg and vgr (p < 0.05), which promoted the synthesis of hepatopancreas exogenous vitellogenin and then transported it into the ovary through the vitellogenin receptor and further promoted ovarian maturation in L. vannamei. Meanwhile, compared with the control group, the expression level of vg in the ovary of the 4.53% Arg group was significantly upregulated (p < 0.05), which indicated endogenous vitellogenin synthesis in ovarian maturation in L. vannamei. Moreover, the expression of genes related to the mechanistic target of the rapamycin complex 1 (mTORC1) pathway and protein levels was regulated by dietary arginine supplementation levels. Arginine metabolism-related products, including nitric oxide synthase (NOS), nitric oxide (NO), and cyclic guanosine monophosphate (cGMP), were also affected. RNA interference was applied here to study the molecular regulation mechanism of arginine on ovarian development in L. vannamei. A green fluorescent protein (GFP)-derived double-stranded RNA (dsGFP) is currently commonly used as a control, while TOR-derived dsRNA (dsTOR) and NOS-derived dsRNA (dsNOS) were designed to build the TOR and NOS in vivo knockdown model. The results showed that the mTORC1 and NO-sGC-cGMP pathways were inhibited, while the vitellogenin receptor and vitellogenin gene expression levels were downregulated significantly in the hepatopancreas and ovary. Overall, dietary arginine supplementation could enhance endogenous and exogenous vitellogenin synthesis to promote ovary development in L. vannamei, and the appropriate dosages were 4.08% and 4.53%. The NO-sGC-cGMP and mTORC1 signaling pathways mediated arginine in the regulation of ovary development in L. vannamei. Full article
(This article belongs to the Section Animal Nutrition)
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13 pages, 2556 KiB  
Article
PTTH–Torso Signaling System Controls Developmental Timing, Body Size, and Reproduction through Regulating Ecdysone Homeostasis in the Brown Planthopper, Nilaparvata lugens
by Xumei Luo, Jinli Zhang, Chuanxi Zhang and Naiming Zhou
Int. J. Mol. Sci. 2024, 25(10), 5138; https://doi.org/10.3390/ijms25105138 - 9 May 2024
Cited by 2 | Viewed by 1421
Abstract
In holometabolous insects, such as Drosophila and Bombyx, prothoracicotropic hormone (PTTH) is well established to be critical in controlling developmental transitions and metamorphosis by stimulating the biosynthesis of ecdysone in the prothoracic glands (PGs). However, the physiological role of PTTH and the [...] Read more.
In holometabolous insects, such as Drosophila and Bombyx, prothoracicotropic hormone (PTTH) is well established to be critical in controlling developmental transitions and metamorphosis by stimulating the biosynthesis of ecdysone in the prothoracic glands (PGs). However, the physiological role of PTTH and the receptor Torso in hemimetabolous insects remains largely unexplored. In this study, homozygous PTTH- and Torso-null mutants of the brown planthopper (BPH), Nilaparvata lugens, were successfully generated by employing clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR–Cas9). Further characterization showed that both NlPTTH/− and NlTorso/− mutants exhibited prolonged nymphal duration and increased final adult size. Enzyme-linked immunosorbent assay (ELISA) revealed that NlPTTH/− and NlTorso/− mutants exhibited a significant reduction in 20-hydroxyecdysone (20E) in fifth-instar nymphs at 48 h post-ecdysis compared to Wt controls. Furthermore, our results indicated that both NlPTTH/− and NlTorso/− mutants had shortened lifespan, reduced female fecundity, and reduced egg hatching rates in adults. These findings suggest a conserved role for the PTTH–Torso signaling system in the regulation of developmental transitions by stimulating ecdysone biosynthesis in hemimetabolous insects. Full article
(This article belongs to the Section Molecular Endocrinology and Metabolism)
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16 pages, 9922 KiB  
Article
RNA Interference-Mediated Suppression of Ecdysone Signaling Inhibits Choriogenesis in Two Coleoptera Species
by Xiao-Qing Zhang, Lin Jin, Wen-Chao Guo, Kai-Yun Fu and Guo-Qing Li
Int. J. Mol. Sci. 2024, 25(8), 4555; https://doi.org/10.3390/ijms25084555 - 22 Apr 2024
Cited by 3 | Viewed by 1404
Abstract
During choriogenesis in insects, chorion (eggshell) is formed by surrounding follicular epithelial cells in ovarioles. However, the regulatory endocrine factor(s) activating choriogenesis and the effect of chemical components on eggshell deserve further exploration. In two representative coleopterans, a coccinellid Henosepilachna vigintioctopunctata and a [...] Read more.
During choriogenesis in insects, chorion (eggshell) is formed by surrounding follicular epithelial cells in ovarioles. However, the regulatory endocrine factor(s) activating choriogenesis and the effect of chemical components on eggshell deserve further exploration. In two representative coleopterans, a coccinellid Henosepilachna vigintioctopunctata and a chrysomelid Leptinotarsa decemlineata, genes encoding the 20-hydroxyecdysone (20E) receptor heterodimer, ecdysone receptor (EcR) and ultraspiracle (USP), and two chitin biosynthesis enzymes UDP-N-acetylglucosamine pyrophosphorylase (UAP) and chitin synthase (ChS1), were highly expressed in ovaries of the young females. RNA interference (RNAi)-aided knockdown of either HvEcR or Hvusp in H. vigintioctopunctata inhibited oviposition, suppressed the expression of HvChS1, and lessened the positive signal of Calcofluor staining on the chorions, which suggests the reduction of a chitin-like substance (CLS) deposited on eggshells. Similarly, RNAi of LdEcR or Ldusp in L. decemlineata constrained oviposition, decreased the expression of LdUAP1 and LdChS1, and reduced CLS contents in the resultant ovaries. Knockdown of LdUAP1 or LdChS1 caused similar defective phenotypes, i.e., reduced oviposition and CLS contents in the L. decemlineata ovaries. These results, for the first time, indicate that 20E signaling activates choriogenesis in two coleopteran species. Moreover, our findings suggest the deposition of a CLS on the chorions. Full article
(This article belongs to the Special Issue Ovary and Testis: Molecular Biological Insights)
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12 pages, 3026 KiB  
Article
Computational Binding Study Hints at Ecdysone 20-Mono-Oxygenase as the Hitherto Unknown Target for Ring C-Seco Limonoid-Type Insecticides
by Ramsés E. Ramírez, Ricardo E. Buendia-Corona, Ivonne Pérez-Xochipa and Thomas Scior
Molecules 2024, 29(7), 1628; https://doi.org/10.3390/molecules29071628 - 5 Apr 2024
Viewed by 1725
Abstract
The insecticidal property of ring C-seco limonoids has been discovered empirically and the target protein identified, but, to date, the molecular mechanism of action has not been described at the atomic scale. We elucidate on computational grounds whether nine C-seco limonoids present sufficiently [...] Read more.
The insecticidal property of ring C-seco limonoids has been discovered empirically and the target protein identified, but, to date, the molecular mechanism of action has not been described at the atomic scale. We elucidate on computational grounds whether nine C-seco limonoids present sufficiently high affinity to bind specifically with the putative target enzyme of the insects (ecdysone 20-monooxygenase). To this end, 3D models of ligands and the receptor target were generated and their interaction energies estimated by docking simulations. As a proof of concept, the tetrahydro-isoquinolinyl propenamide derivative QHC is the reference ligand bound to aldosterone synthase in the complex with PDB entry 4ZGX. It served as the 3D template for target modeling via homology. QHC was successfully docked back to its crystal pose in a one-digit nanomolar range. The reported experimental binding affinities span over the nanomolar to lower micromolar range. All nine limonoids were found with strong affinities in the range of −9 < ΔG < −13 kcal/mol. The molt hormone ecdysone showed a comparable ΔG energy of −12 kcal/mol, whereas −11 kcal/mol was the back docking result for the liganded crystal 4ZGX. In conclusion, the nine C-seco limonoids were strong binders on theoretical grounds in an activity range between a ten-fold lower to a ten-fold higher concentration level than insecticide ecdysone with its known target receptor. The comparable or even stronger binding hints at ecdysone 20-monooxygenase as their target biomolecule. Our assumption, however, is in need of future experimental confirmation before conclusions with certainty can be drawn about the true molecular mechanism of action for the C-seco limonoids under scrutiny. Full article
(This article belongs to the Special Issue In Silico Methods Applied in Drug and Pesticide Discovery)
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16 pages, 1965 KiB  
Article
Assessing the Interactive Effects of High Salinity and Stocking Density on the Growth and Stress Physiology of the Pacific White Shrimp Litopenaeus vannamei
by Fei Liu, Jinfeng Sun, Jinnan Long, Lichao Sun, Chang Liu, Xiaofan Wang, Long Zhang, Pengyuan Hao, Zhongkai Wang, Yanting Cui, Renjie Wang and Yuquan Li
Fishes 2024, 9(2), 62; https://doi.org/10.3390/fishes9020062 - 31 Jan 2024
Cited by 3 | Viewed by 3397
Abstract
This study was conducted to evaluate the effects of high salinity combined with stocking density on Litopenaeus vannamei. Three salinity gradients, namely, 28 g/L, 36 g/L, and 44 g/L, and two stocking densities, namely, 300 and 600 shrimp/m3, were used [...] Read more.
This study was conducted to evaluate the effects of high salinity combined with stocking density on Litopenaeus vannamei. Three salinity gradients, namely, 28 g/L, 36 g/L, and 44 g/L, and two stocking densities, namely, 300 and 600 shrimp/m3, were used to analyze the synergistic effect of high salinity and stocking density on the growth performance, digestibility, and energy budgets of L. vannamei. The experimental testing period lasted 45 days. The research results showed that a salinity level of 36 g/L was the most suitable salinity level for shrimp growth under both high and low stocking densities. The body weight, specific growth rate, and relative weight gain of the shrimp in the 36 g/L salinity group were significantly higher than those in the other two salinity groups under both high and low stocking densities. The high-density farming group with 600 shrimp/m3 exhibited a significant inhibition of shrimp growth compared to the low-density group under the same salinity conditions. The activities of amylase, lipase, and protease in the high-density-group shrimp gradually decreased with an increase in salinity, and the three digestive enzymes had the same overall effect of changing trends. This indicates that under high-density farming conditions, the increase in salinity is not conducive to the digestive function of shrimps. At the same time, the proportion of respiratory energy to feeding energy gradually decreased in the high-density group and with the increase in salinity. However, under the same salinity conditions, the higher the stocking density, the higher the energy consumed by respiration compared to the low-density group. In addition, the expression of the growth-related gene’s small nuclear ribonucleoprotein polypeptide G (SNRPG) under high stocking density was significantly lower than that in the low-density group at a salinity of 28 g/L, and ribosomal protein L7 (RPL7) expression was also significantly lower under high stocking density than that in the low-density group at a salinity of 44 g/L. The expression levels of molting-related genes retinoid X receptor (RXR), ecdysone receptor (ECR), and ecdysone-induced protein 75 (E75) were significantly higher in the 36 g/L salinity group compared with the other two salinity groups under high-stocking-density treatment. The findings indicate that the synergistic effects of salinity and stocking density have a significant impact on the growth of L. vannamei, and excessive salinity would inhibit its growth in the process of high-density culturing. Full article
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24 pages, 8514 KiB  
Article
The Sterol Transporter Npc2c Controls Intestinal Stem Cell Mitosis and Host–Microbiome Interactions in Drosophila
by Constantina Neophytou, Euripides Soteriou and Chrysoula Pitsouli
Metabolites 2023, 13(10), 1084; https://doi.org/10.3390/metabo13101084 - 16 Oct 2023
Cited by 1 | Viewed by 3061
Abstract
Cholesterol is necessary for all cells to function. The intracellular cholesterol transporters Npc1 and Npc2 control sterol trafficking and their malfunction leads to Neimann–Pick Type C disease, a rare disorder affecting the nervous system and the intestine. Unlike humans that encode single Npc1 [...] Read more.
Cholesterol is necessary for all cells to function. The intracellular cholesterol transporters Npc1 and Npc2 control sterol trafficking and their malfunction leads to Neimann–Pick Type C disease, a rare disorder affecting the nervous system and the intestine. Unlike humans that encode single Npc1 and Npc2 transporters, flies encompass two Npc1 (Npc1a-1b) and eight Npc2 (Npc2a-2h) members, and most of the Npc2 family genes remain unexplored. Here, we focus on the intestinal function of Npc2c in the adult. We find that Npc2c is necessary for intestinal stem cell (ISC) mitosis, maintenance of the ISC lineage, survival upon pathogenic infection, as well as tumor growth. Impaired mitosis of Npc2c-silenced midguts is accompanied by reduced expression of Cyclin genes, and genes encoding ISC regulators, such as Delta, unpaired1 and Socs36E. ISC-specific Npc2c silencing induces Attacin-A expression, a phenotype reminiscent of Gram-negative bacteria overabundance. Metagenomic analysis of Npc2c-depleted midguts indicates intestinal dysbiosis, whereby decreased commensal complexity is accompanied by increased gamma-proteobacteria. ISC-specific Npc2c silencing also results in increased cholesterol aggregation. Interestingly, administration of the non-steroidal ecdysone receptor agonist, RH5849, rescues mitosis of Npc2c-silenced midguts and increases expression of the ecdysone response gene Broad, underscoring the role of Npc2c and sterols in ecdysone signaling. Assessment of additional Npc2 family members indicates potential redundant roles with Npc2c in ISC control and response to ecdysone signaling. Our results highlight a previously unidentified essential role of Npc2c in ISC mitosis, as well as an important role in ecdysone signaling and microbiome composition in the Drosophila midgut. Full article
(This article belongs to the Special Issue Host-Microbe-Metabolite Interaction in Intestinal Health)
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16 pages, 2842 KiB  
Article
RNAi-Mediated Functional Analysis Reveals the Regulation of Oocyte Vitellogenesis by Ecdysone Signaling in Two Coleoptera Species
by Xiaoqing Zhang, Lin Jin and Guoqing Li
Biology 2023, 12(10), 1284; https://doi.org/10.3390/biology12101284 - 26 Sep 2023
Cited by 7 | Viewed by 1818
Abstract
Coleoptera is the largest taxa of animals by far. The robust reproductive capacity is one of the main reasons for such domination. Successful female reproduction partially relies on effective vitellogenesis. However, the hormone regulation of vitellogenesis remains to be explored. In the present [...] Read more.
Coleoptera is the largest taxa of animals by far. The robust reproductive capacity is one of the main reasons for such domination. Successful female reproduction partially relies on effective vitellogenesis. However, the hormone regulation of vitellogenesis remains to be explored. In the present paper, in vitro culture of Leptinotarsa decemlineata 1-day-old adult fat bodies in the 20E-contained median did not activate juvenile hormone production and insulin-like peptide pathways, but significantly stimulated the expression of two LdVg genes, in a cycloheximide-dependent pattern. In vivo RNA interference (RNAi) of either ecdysone receptor (LdEcR) or ultraspiracle (Ldusp) by injection of corresponding dsRNA into 1-day-old female adults inhibited oocyte development, dramatically repressed the transcription of LdVg genes in fat bodies and of LdVgR in ovaries; application of JH into the LdEcR or Ldusp RNAi L. decemlineata females did not restore the oocyte development, partially rescued the decreased LdVg mRNA levels but over-compensated LdVgR expression levels. The same RNAi experiments were performed in another Coleoptera species, Henosepilachna vigintioctopunctata. Little yolk substances were seen in the misshapen oocytes in the HvEcR or Hvusp RNAi ovaries, in contrast to larger amounts of yolk granules in the normal oocytes. Correspondingly, the transcript levels of HvVg in the fat bodies and ovaries decreased significantly in the HvEcR and Hvusp RNAi samples. Our results here show that 20E signaling is indispensable in the activation of vitellogenesis in the developing oocytes of the two beetle species. Full article
(This article belongs to the Section Developmental and Reproductive Biology)
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