Search Results (35)

Cytoplasmic polyadenylation element-binding proteins (CPEBs) are critical regulators of maternal mRNA translation during oogenesis, yet their roles in insect reproduction remain underexplored. Here, we characterized CmCPEB2, a CPEB homolog in the rice leaf roller Cnaphalocrocis medinalis, a destructive lepidopteran pest insect, and elucidated its role in mating-induced oviposition. The CmCPEB2 protein harbored conserved RNA recognition motifs and a ZZ-type zinc finger domain and was phylogenetically clustered with lepidopteran orthologs. Spatiotemporal expression profiling revealed CmCPEB2 was predominantly expressed in ovaries post-mating, peaking at 12 h with a 6.75-fold increase in transcript levels. Liposome-mediated RNA interference targeting CmCPEB2 resulted in a 52% reduction in transcript abundance, leading to significant defects in ovarian maturation, diminished vitellogenin deposition, and a 36.7% decline in fecundity. The transcriptomic analysis of RNAi-treated ovaries identified 512 differentially expressed genes, with downregulated genes enriched in chorion formation and epithelial cell development. Tissue culture-based hormonal assays demonstrated the juvenile hormone-dependent regulation of CmCPEB2, as JH treatment induced its transcription, while knockdown of the JH-responsive transcription factor CmKr-h1 in the moths suppressed CmCPEB2 expression post-mating. These findings established CmCPEB2 as a juvenile hormone-dependent regulator of mating-induced oviposition that orchestrates vitellogenesis through yolk protein synthesis and ovarian deposition and choriogenesis via transcriptional control of chorion-related genes. This study provides novel evidence of CPEB2-mediated reproductive regulation in Lepidoptera, highlighting its dual role in nutrient allocation and structural eggshell formation during insect oogenesis and oviposition. Full article

Insects face the constant challenge of balancing energy allocation between reproduction and immune responses, both of which are highly energy-demanding processes. Immune challenges frequently result in decreased fecundity, reduced egg viability, and delayed ovarian development. Conversely, heightened reproductive activity often suppresses immune functions. This trade-off has profound ecological and evolutionary consequences, shaping insects’ survival, adaptation, and population dynamics. The intricate interplay between reproduction and immunity in insects is regulated by the neuroendocrine and endocrine systems, which orchestrate resource distribution alongside other biological processes. Key hormones, such as juvenile hormone and ecdysteroids, serve as central regulators, influencing both immune responses and reproductive activities. Additionally, macromolecules like vitellogenin and lipophorin, primarily known for their functions as yolk protein precursors and lipid carriers, play crucial roles in pathogen recognition and transgenerational immune priming. Advancements in molecular and omics tools have unveiled the complexity of these regulatory mechanisms, providing new insights into how insects dynamically allocate resources to optimize their fitness. This delicate balance underscores critical evolutionary strategies and the integration of physiological systems across species. This review synthesizes insights from life history theory, oogenesis, and immunity, offering new perspectives on the trade-offs between reproductive output and immune investment. Full article

This study evaluated the effects of kaempferol (KAE), and vitamin E (VE) on the performance, reproductive hormones, and the composition of the cecum and uterus microbiota in late-laying hens. A total of 192 49-week-old Jinghong No. 1 laying hens were randomly divided into four groups, with six replicates in each group and eight laying hens in each replicate, pre-reared for one week and formally tested for ten weeks. The CON group was fed basal diets, the VE group, the KAE group, and the KAE + VE group were fed a basal diet to which was added 0.2 g/kg VE, 0.4 g/kg KAE, and 0.2 g/kg VE + 0.4 g/kg KAE, respectively. The results are as follows. Compared to the CON group, the VE group, the KAE group, and the KAE + VE group significantly increased the egg production rate, average daily egg weight and significantly decreased the feed-to-egg ratio. The VE + KAE group significantly improved the Haugh unit. The VE group, the KAE group, and the KAE + VE group considerably enhanced the eggshell strength, eggshell relative weight, eggshell thickness, yolk color, and relative yolk weight. The serum E₂ and LH levels of the KAE group and the KAE + VE group and the serum FSH levels of the KAE + VE group were significantly higher. In the ovary, the KAE group and the KAE + VE group’s ESR1 gene expression levels were significantly higher, and the KAE + VE group’s FSHR gene expression levels were markedly higher. In the uterus, the KAE group and the KAE + VE group’s ESR1 gene expression levels were dramatically higher, and the KAE + VE group’s ESR2 and FSHR gene expression levels were significantly higher. 16S rRNA gene sequencing revealed a significant aggregation of cecum and uterus colonies in the Beta diversity PCoA. In the cecum, Firmicutes, Bacteroidetes, and WPS-2 were the dominant phylums. In the uterus, the Firmicutes, Proteobacteria, and Bacteroidetes were the dominant phylums. The KAE + VE group’s F/B was significantly higher at the phylum level than in the CON group and the VE group. In summary, the addition of VE and KAE to the diet can improve the production performance of late-laying hens, increase the content of reproductive hormones, and stabilize the cecal and uterus microbiota, which may be related to the hormone and microbiota linkage of the gut–uterus axis. Full article

Numerous studies have explored alternative protein sources to fishmeal (FM) to enhance fish diets, yet limited research exists on their effects on maturation. This study assessed the impact of replacing FM with soy protein concentrate (SPC) supplemented with lysine and methionine on growth and gonadal development in olive flounder (Paralichthys olivaceus). Three diets were tested: a control (Con) diet with 60% FM and two diets replacing FM with 25% (LF1) and 50% (LF2) SPC. Fish were fed to apparent satiation twice daily for 12 months. Growth performance and feed intake were not significantly different between groups. However, the gonadosomatic index varied with diet. Muscle composition and amino acid levels were similar across treatments, though n-3 fatty acids were higher in Con. Spermatogonia was increased, and spermatogenesis was impaired in SPC groups. At 12 months, oocytes in Con diets had absorbed yolk globules, whereas this was absent in SPC groups. Growth-related genes in the brain (growth hormones and insulin-like growth factor) were increased with higher SPC, while follicle-stimulating and luteinizing hormones decreased. Estrogen receptor α levels were elevated in SPC groups. Vitellogenin gene expression in gonads was highest in Con, while liver expression peaked in LF2. The expression of digestive enzymes, chymotrypsin2, and trypsin2 was highest in LF2, while lipase genes were lower. In summary, up to 50% FM replacement with SPC, with amino acid supplementation, supported growth performance and muscle composition without adverse effects on growth in olive flounder but influenced gonadal development. Full article

Vitamin D is a conditionally essential fat-soluble vitamin found in foods such as fish; fish oil; egg yolks; animal fats; some mushroom varieties; and fortified foods such as cheese, margarine, milk, infant formula, and some ready-to-eat cereals. Calcium (Ca) is found in milk, cheese, canned fish, ready-to-eat cereals, milk substitutes, dark green leafy vegetables, and sports drinks. There are more than fifty metabolites of vitamin D. Vitamin D participates in immune regulation, apoptosis induction, insulin secretion, inflammation, cell differentiation, calcium balance and regulation, bone mineralization, and phosphorus homeostasis. Ca is an essential macro-mineral involved in bone and teeth matrices, strength, and hardness; muscle and cardiovascular movement; neurological messaging; and in the release of hormones. Peer-reviewed journal articles were accessed from the search engine PubMed. The authors reviewed the references in the peer-reviewed journal articles, websites, and review articles if the authors proposed a new theory or mechanism. Vitamin D and Ca have important relationships; therefore, many factors may impede or interfere with the body’s ability to absorb or utilize vitamin D and or Ca and may result in low or excessive levels of each. Additionally, genetic/medically related absorption issues and low intake may also result in deficiencies. This review discusses the introduction of each, their functions, absorption, somatic transportation, the relationship between vitamin D and Ca, and recommendations and supplementation strategies if available. Full article

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

Cirrhinus mrigala is an important edible fish with a significant aquaculture contribution in Southeast Asian countries. The current study aims to enhance our understanding of the developmental biology of Cirrhinus mrigala, which is crucial for implementing sustainable fish farming practices. To induce spermiation and ovulation in Cirrhinus mrigala brooders, the synthetic hormone Ovaprim^® (GnRH + dopamine inhibitor) was administrated as a single injection dose of 0.2 mL/kg to males and 0.4 mL/kg to females. After induction, the fish spawned, and the eggs produced were fertilized artificially and cell division commenced successfully. The characteristics of each larval developmental stage were closely observed and recorded using a time-lapse imaging technique. The fertilized eggs were spherical, demersal, and non-adhesive throughout their incubation period. The spawned eggs ranged in diameter from 2.1 mm to 2.13 mm and possessed circular yolk sacs. The gastrula stage initiated approximately 4 h after fertilization, with 25% of the yolk sphere covered by blastoderm, reaching 75% coverage at the end of the gastrula stage, approximately 6 h post fertilization. Organogenesis was marked by the formation of notochord and the visibility of rudimentary organs such as the heart, eyes, and gills, followed by tail movement, which was observed at the time of hatching. Compared to other cyprinid fishes, C. mrigala exhibited distinct features at certain stages of embryonic development. Blood circulation was observed to start at the onset of hatching. The lengths of the newly hatched larvae ranged from 2.9 to 3.2 mm, smaller than other reports on induced breeding in carps. The findings of the present study provide a detailed reference for the embryonic development of C. mrigala, which will assist its future research endeavors and large-scale seed production for sustainable aquaculture. Full article

Red light (RL) has been observed to enhance egg production in pigeons, yet the underlying histological characteristics and molecular mechanisms remain less understood. This study included fifty-four pigeons to assess follicular histology, reproductive hormones, and ovarian transcriptomics on the third day of the laying interval under RL and white light (WL). The results showed that the granulosa cell layer was significantly thicker under RL (p < 0.05), whereas the theca cell and connective tissue layers showed no significant differences (p > 0.05). Higher plasma estradiol (E₂) levels were recorded in the RL group (p < 0.05), as well as follicle stimulating hormone (FSH), although progesterone (P₄) levels were higher under WL (p < 0.05). Moreover, P₄ concentrations in follicle yolk significantly decreased under RL (p < 0.01), with higher FSH and E₂ levels in F1 yolk and similar increases in SF1 yolk (p < 0.01). Transcriptomic analysis revealed 4991 differentially expressed genes in the pigeon ovary. The protein–protein interaction network highlighted genes like HSD11B1, VEGFD, WNT6, SMAD6, and LGR5 as potential contributors to hierarchical follicle selection under RL. This research provides new insights into the molecular basis by which RL may promote hierarchical follicle selection and improve egg production in pigeons. Full article

Coilia nasus is a typical anadromous migratory fish found in the lower reaches of the Yangtze River. Every year, C. nasus clusters offshore and swims upstream along the Yangtze River into the tributaries and lakes in the middle and lower reaches of the Yangtze River to breed. In this study, female C. nasus were collected as study subjects from the Chongming section of Shanghai, the Taizhou section of Jiangsu, and the Anqing section of Anhui. Their ovaries were used to examine tissue sections and investigate gene expression, including the follicle-stimulating hormone receptor (fshr), the luteinizing hormone receptor (lhr), kisspeptin-1 (kiss1), and forkhead box l2 (foxl2), which are related to reproductive development, while the serum levels of estrogen (including estradiol, E2) and progestins (including 17α,20β-dihydroxy-4-pregenen-3-one, 17α,20β-DHP) were also analyzed. Our results showed that, first, the growth period of the oocytes was small in stage II of ovarian development, in which both E2 and 17α,20β-DHP levels and gene expression were low. Then, in stage III, the growth period of the oocytes became large, and the yolk granules and oil droplets began to appear. Simultaneously, E2 and the expression of kiss1 and foxl2 were significantly elevated. Finally, stage IV was the period of a large amount of accumulation of nutrients in the oocytes, and 17α,20β-DHP levels and the expression of fshr and lhr were significantly elevated. These results enrich the theoretical study of ovarian development in the natural population of C. nasus, supplementing the biological basis of C. nasus reproduction and scientifically supporting the study of C. nasus population ecology and resource conservation. Full article

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

To induce oocyte development, eels are weekly injected with salmon or carp pituitary extract (CPE). The weekly handling and hormone peaks result in inferior oocyte quality; therefore, alternative treatments that improve oocyte quality and reproductive success require investigation. The enhancement of early sexual maturation by a single injection with human chorionic gonadotropin (hCG), administered prior to CPE treatment, was investigated. Fifty feminized eels were subjected to simulated migration, after which eels received either a hCG or a sham injection. After two months, the hCG-treated eels showed an increase in eye size, gonadosomatic index (GSI), and plasma 11-ketotestosterone concentration, when compared with the sham-injected controls. The hCG-treated eels showed increases in oocyte diameter and lipid area, and in ovarian expression of aromatase (cyp19), follicle stimulating hormone receptor (fshr) and lipoprotein lipase (lpl). Yolk was present in the oocytes of the hCG-treated eels, not yet in the oocytes of the controls. The hCG-induced deposition of yolk may relate to early-life treatment with 17β-estradiol during feminization. hCG-treated eels required four CPE injections less to mature than the controls. hCG treatment may benefit reproductive success in feminized eels by initiating vitellogenesis and reducing the hypophysation period, although larvae were obtained from most females in both groups. Full article

Maternal hormones such as estrogens deposited into the yolk of turtle eggs follow circulating levels in adult females, and they may alter the sexual fate of developing embryos in species with temperature-dependent sex determination (TSD). In temperate regions, this deposition occurs during the spring when estrogens increase in adult females as ambient temperatures rise, drop after the first clutch, and peak again (albeit less) in the fall. Global warming alters turtle nesting phenology (inducing earlier nesting), but whether it affects circulating hormones remains unknown, hindering our understanding of all potential challenges posed by climate change and the adaptive potential (or lack thereof) of turtle populations. Here, we addressed this question in painted turtles (Chrysemys picta) by quantifying estradiol, estrone, and testosterone via mass spectrometry in the blood of wild adult females exposed to 26 °C and 21 °C in captivity between mid-August and mid-October (15 females per treatment). Results from ANOVA and pairwise comparisons revealed no differences between treatments in circulating hormones measured at days 0, 2, 7, 14, 28, and 56 of the experiment. Further research is warranted (during the spring, using additional temperatures) before concluding that females are truly buffered against the indirect risk of climate change via maternal hormone allocation. Full article

In order to decipher the functional genes and reveal the molecular mechanism of gonadal development in Macrobrachium rosenbergii, a comparative transcriptome analysis was performed on the testes and ovaries at different developmental stages. A total of 146,537 unigenes with an N50 of 2008 bp and an average length of 1144 bp were obtained from the sequencing raw data via quality control and denovo assembly. Identification of differentially expressed genes (DEGs) showed that there were 339 and 468 DEGs among the different developmental stages of testes and ovaries, respectively, and 7993 DEGs between the testes and ovaries. The KEGG enrichment analysis identified 13 candidate pathways related to gonadal development, including insulin synthesis, oocyte maturation, and steroid biosynthesis, which were involved in biological processes such as regulation of hormone metabolism, sex cell proliferation and development, and amino acid metabolism. The DEGs related to the above pathways such as insulin-like growth factor 1 receptor (IGF1R), heat shock protein 90 (Hsp 90), and cyclooxygenase (COX) genes were highly expressed during yolk protein synthesis, indicating that these genes might be involved in yolk accumulation and oogenesis. Meanwhile, calmodulin (CaM) and other genes were highly expressed during spermatogenesis, suggesting that these genes might play an important role in spermatogenesis. Ten differentially expressed genes in the KEGG signaling pathway, including CRQ, COX, APP, Cdc42, Hsd17b12, Art-1, Hsp70, Hsp90, PRMT1, and GP, were selected for real-time quantitative PCR (RT- qPCR) to validate the transcriptome data, and the results showed that RT- qPCR obtained consistent results with the RNA-Seq data. The present findings provide new insights into the molecular regulation mechanism of gonadal development in M. rosenbergii. Full article

In adult females of several insect species, juvenile hormones (JHs) act as gonadotrophic hormones, regulating egg production. JH binds to its nuclear receptor, Methoprene tolerant (Met), triggering its dimerization with the protein Taiman (Tai). The resulting active complex induces transcription of JH response genes, such as Krüppel homolog 1 (Kr-h1). In this study we report for the first time the participation of the isoform JH III skipped bisepoxide (JHSB₃) and its signaling pathway in the reproductive fitness of the classical insect model Rhodnius prolixus. The topical application of synthetic JHSB₃ increases transcript and protein expression of yolk protein precursors (YPPs), mainly by the fat body but also by the ovaries, the second source of YPPs. These results are also confirmed by ex vivo assays. In contrast, when the JH signaling cascade is impaired via RNA interference by downregulating RhoprMet and RhoprTai mRNA, egg production is inhibited. Although RhoprKr-h1 transcript expression is highly dependent on JHSB₃ signaling, it is not involved in egg production but rather in successful hatching. This research contributes missing pieces of JH action in the insect model in which JH was first postulated almost 100 years ago. Full article

Cotton is the most important crop for fiber production worldwide. However, the cotton boll weevil (CBW) is an insect pest that causes significant economic losses in infested areas. Current control methods are costly, inefficient, and environmentally hazardous. Herein, we generated transgenic cotton lines expressing double-stranded RNA (dsRNA) molecules to trigger RNA interference-mediated gene silencing in CBW. Thus, we targeted three essential genes coding for chitin synthase 2, vitellogenin, and ecdysis-triggering hormone receptor. The stability of expressed dsRNAs was improved by designing a structured RNA based on a viroid genome architecture. We transformed cotton embryos by inserting a promoter-driven expression cassette that overexpressed the dsRNA into flower buds. The transgenic cotton plants were characterized, and positive PCR transformed events were detected with an average heritability of 80%. Expression of dsRNAs was confirmed in floral buds by RT-qPCR, and the T₁ cotton plant generation was challenged with fertilized CBW females. After 30 days, data showed high mortality (around 70%) in oviposited yolks. In adult insects fed on transgenic lines, chitin synthase II and vitellogenin showed reduced expression in larvae and adults, respectively. Developmental delays and abnormalities were also observed in these individuals. Our data remark on the potential of transgenic cotton based on a viroid-structured dsRNA to control CBW. Full article