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Frontiers in Genetics 2022Assisted propagation of the European eel will lead to a closed production cycle supplying the aquaculture industry with juvenile glass eels. Females require long-term...
Assisted propagation of the European eel will lead to a closed production cycle supplying the aquaculture industry with juvenile glass eels. Females require long-term weekly treatment with pituitary extract (PE), which is stressful and causes abnormalities in oogenesis. We tested the effects of 17α-methyltestosterone (17 MT), as potent androgen activating the androgen receptor, and 17β-estradiol (E2), as an inducer of vitellogenesis, to shorten the duration of PE treatment.Four groups of feminized eels were subjected to a simulated migration and subsequent injection with implants containing 17 MT (17 MT-group), E2 (E2-group) or 17 MT plus E2 (17 MT + E2-group) to test for synergistic effects, or without any steroids as controls (C-group). The effects of a 2-months treatment were investigated by determining the eye index (EI), hepatosomatic and gonadosomatic index (HSI and GSI, respectively), plasma steroid concentrations by liquid chromatography mass spectrometry (LCMS), gonadal histology, expression of androgen receptors a and b (, ); estrogen receptor 1 (); FSH receptor (); vitellogenin receptor () and aromatase (), and the required number of weekly PE injections to fully mature. For many parameters, both the 17 MT and E2 groups showed an increase vs. controls, with the 17 MT + E2 group showing a synergistic effect, as seen for EI, GSI (3.4 for 17 MT and for E2, 6.6 for 17 MT + E2), oocyte diameter and , and expression. Concentrations of almost all focal steroids decreased with simulated migration and steroid treatment. Only eels of the 17 MT-group showed increased expression of and of , while expression increased 44-fold in the 17 MT + E2 group, highlighting that co-implantation is most effective in raising mRNA levels. Specific for eels of the E2 groups were vitellogenesis-associated changes such as an increase of HSI, plasma E2, and presence of yolk in the oocytes. Steroid treatments reduced the duration of PE treatment, again synergistically for co-implantation. In conclusion, E2 is necessary to start vitellogenesis, but 17 MT has specific effects on and expression. The combination is necessary for synergistic effects and as such, steroid implants could be applied in assisted reproduction protocols for European eel to improve oocyte quality leading to the production of more vital larvae.
PubMed: 36061169
DOI: 10.3389/fgene.2022.969202 -
Communications Biology Aug 2022Chlorops oryzae is a pest of rice that has caused severe damage to crops in major rice-growing areas in recent years. We generated a 447.60 Mb high-quality...
Chlorops oryzae is a pest of rice that has caused severe damage to crops in major rice-growing areas in recent years. We generated a 447.60 Mb high-quality chromosome-level genome with contig and scaffold N50 values of 1.17 Mb and 117.57 Mb, respectively. Hi-C analysis anchored 93.22% scaffolds to 4 chromosomes. The relatively high expression level of Heat Shock Proteins (HSPs) and antioxidant genes in response to thermal stress suggests these genes may play a role in the environmental adaptability of C. oryzae. The identification of multiple pathways that regulate reproductive development (juvenile hormone, 20-hydroxyecdsone, and insulin signaling pathways) provides evidence that these pathways also play an important role in vitellogenesis and thus insect population maintenance. These findings identify possible reasons for the increased frequency of outbreaks of C. oryzae in recent years. Our chromosome-level genome assembly may provide a basis for further genetic studies of C. oryzae, and promote the development of novel, sustainable strategies to control this pest.
Topics: Animals; Chromosomes; Diptera; Disease Outbreaks; Genome; Phylogeny
PubMed: 36028584
DOI: 10.1038/s42003-022-03850-7 -
International Journal of Molecular... Aug 2022During their breeding season, estrogen induces vitellogenin (VTG) production in the liver of teleost fish through estrogen receptors (ERs) that support oocyte...
During their breeding season, estrogen induces vitellogenin (VTG) production in the liver of teleost fish through estrogen receptors (ERs) that support oocyte vitellogenesis. There are at least three ER subtypes in teleost fish, but their roles in mediating E-induced VTG expression have yet to be ascertained. In this study, we investigated the expression of and in the liver of orange-spotted grouper (). Their expression levels were significantly increased in the breeding season and were upregulated by an estradiol (E) injection in female fish, except for the expression of . The upregulation of , and by E was also observed in primary hepatocytes, but these stimulatory effects could be abolished by ER antagonist ICI182780 treatment. Subsequent studies showed that ERβ antagonist Cyclofenil downregulated the E-induced expression of , , and , while the ERβ agonist DPN simulated their expression. Knockdown of by siRNA further confirmed that ERβ2 mediated the E-induced expression of and . To reveal the mechanism of ERβ2 in the regulation of expression, the promoter was cloned, and its activity was examined in cells. E treatment simulated the activity of the promoter in the presence of ERβ2. Deletions and site-directed mutations showed that the E up-regulated transcriptional activity of occurs through a classical half-estrogen response element- (ERE) dependent pathway. This study reveals the roles of ER subtypes in VTG expression in orange-spotted grouper and provides a possible explanation for the rapid and efficient VTG production in this species during the breeding season.
Topics: Animals; Bass; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogens; Female; Receptors, Estrogen; Vitellogenins
PubMed: 35955769
DOI: 10.3390/ijms23158632 -
PLoS Genetics Jun 2022Juvenile hormone (JH) acts as a gonadotrophic hormone stimulating insect vitellogenesis and oogenesis. Paracellular transport of yolk proteins through intercellular...
Juvenile hormone (JH) acts as a gonadotrophic hormone stimulating insect vitellogenesis and oogenesis. Paracellular transport of yolk proteins through intercellular channels (patency) in the follicular epithelium is a developmentally regulated and evolutionarily conserved process during vitellogenesis. However, the mechanisms underlying patency opening are poorly understood. Using the migratory locust Locusta migratoria as a model system, we report here that JH-regulated remodeling of zonula adherens (ZA), the belt-like adherens junction maintaining physical linking between follicle cells controlled the opening of patency. JH triggered phosphorylation of Partitioning defective protein 3 (Par3) via a signaling cascade including G protein-coupled receptor (GPCR), small GTPase Cell division cycle 42 (Cdc42) and atypical Protein kinase C (aPKC). Par3 phosphorylation resulted in its disassociation from β-Catenin, the cytoplasmic partner of ZA core component E-Cadherin. Release of Par3 from the β-Catenin/E-Cadherin complex caused ZA disassembly at tricellular contacts, consequently leading to patency enlargement. This study provides new insight into how JH stimulates insect vitellogenesis and egg production via inducing the opening of paracellular route for vitellogenin transport crossing the follicular epithelium barrier.
Topics: Adherens Junctions; Cadherins; Epithelium; Juvenile Hormones; Vitellogenins; beta Catenin
PubMed: 35759519
DOI: 10.1371/journal.pgen.1010292 -
Proceedings of the National Academy of... Jun 2022The primary insect steroid hormone ecdysone requires a membrane transporter to enter its target cells. Although an organic anion-transporting polypeptide (OATP) named...
The primary insect steroid hormone ecdysone requires a membrane transporter to enter its target cells. Although an organic anion-transporting polypeptide (OATP) named Ecdysone Importer (EcI) serves this role in the fruit fly and most likely in other arthropod species, this highly conserved transporter is apparently missing in mosquitoes. Here we report three additional OATPs that facilitate cellular incorporation of ecdysone in and the yellow fever mosquito . These additional ecdysone importers (EcI-2, -3, and -4) are dispensable for development and reproduction in , consistent with the predominant role of EcI. In contrast, in , EcI-2 is indispensable for ecdysone-mediated development, whereas EcI-4 is critical for vitellogenesis induced by ecdysone in adult females. Altogether, our results indicate unique and essential functions of these additional ecdysone importers in mosquito development and reproduction, making them attractive molecular targets for species- and stage-specific control of ecdysone signaling in mosquitoes.
Topics: Aedes; Animals; Drosophila; Drosophila melanogaster; Ecdysone; Female; Insect Proteins; Organic Anion Transporters; Vitellogenesis
PubMed: 35696563
DOI: 10.1073/pnas.2202932119 -
Frontiers in Genetics 2022Ovarian development is a key physiological process that holds great significance in the reproduction of the Chinese mitten crab (), which is an economically important...
Ovarian development is a key physiological process that holds great significance in the reproduction of the Chinese mitten crab (), which is an economically important crab species for aquaculture. However, there is limited knowledge for the regulatory mechanisms of ovarian development. To study the molecular mechanisms of its ovarian development, transcriptome analysis was performed in the ovary and hepatopancreas of during ovarian stages I (oogonium proliferation), II (endogenous vitellogenesis), and III (exogenous vitellogenesis). The results showed that 5,520 and 226 genes were differentially expressed in the ovary and hepatopancreas, respectively. For KEGG enrichment analysis, the differentially expressed genes in the ovary were significantly clustered in phototransduction-fly, phagosome, and ECM-receptor interaction. Significantly enriched pathways in the hepatopancreas included fatty acid biosynthesis, fatty acid metabolism, and riboflavin metabolism. Further analysis showed that 25 genes and several pathways were mainly involved in oogenesis, including the ubiquitin-proteasome pathway, cyclic AMP-protein kinase A signaling pathway, and mitogen-activated protein kinase signaling pathway. Twenty-five candidate genes involved in vitellogenesis and endocrine regulation were identified, such as vitellogenin, vitellogenin receptor, estrogen sulfotransferase, ecdysone receptor, prostaglandin reductase 1, hematopoietic prostaglandin D synthase and juvenile hormone acid O-methyltransferase. Fifty-six genes related to nutritional metabolism were identified, such as fatty acid synthase, long-chain-fatty-acid-CoA ligase 4, 1-acyl-sn-glycerol-3-phosphate acyltransferase 4, fatty acid-binding protein, and glycerol-3-phosphate acyltransferase 1. These results highlight the genes involved in ovarian development and nutrition deposition, which enhance our understanding of the regulatory pathways and physiological processes of crustacean ovarian development.
PubMed: 35685440
DOI: 10.3389/fgene.2022.910682 -
Animals : An Open Access Journal From... May 2022The sub-order Scorpenoidei appears to be particularly interesting due to the presence of intermediate stages between oviparity and viviparity in several species. The...
The sub-order Scorpenoidei appears to be particularly interesting due to the presence of intermediate stages between oviparity and viviparity in several species. The present study aims to describe the ovarian morphology, using a histological and histochemical approach, in four ovuliparous species belonging to genus compared with a zygoparous species, , focusing also on the assessment of the ovarian dynamics in the populations of such species in Sardinia waters (central-western Mediterranean). Ovarian sections of all species were examined using light microscopy. All species showed a specialized ovary, cystovarian type II-3, strictly related to the production of gelatinous matrices surrounding the eggs. Some microscopic peculiarities in the oogenesis process were found: thin zona pellucida, small and low cortical alveoli, and a specialized ovarian wall during the spawning period. All species analyzed were batch-spawners with an asynchronous ovarian organization. A continuous recruitment of oocytes and the occurrence of de novo vitellogenesis was also observed. During the spawning period, low atresia intensity was detected, while a marked increase in this intensity found in the ovaries at the end of spawning season. Our observations may support an indeterminate fecundity type for these species.
PubMed: 35681876
DOI: 10.3390/ani12111412 -
Insect Science Feb 2023Oocyte maturation is critical for insect reproduction. Vitellogenesis, the timely production and uptake of vitellogenin (Vg), is crucial for female fecundity. Vg is...
Oocyte maturation is critical for insect reproduction. Vitellogenesis, the timely production and uptake of vitellogenin (Vg), is crucial for female fecundity. Vg is synthesized in fat body and absorbed by the oocytes through endocytosis during insect oogenesis. In the silkworm, Bombyx mori, we discovered that a nucleus-enriched long-noncoding RNA (lncRNA) lncR26319 regulates Endophilin A (EndoA) - a member of the endophilin family of endocytic proteins - through competitive binding to miR-2834. The lncR26319-miR-2834-EndoA axis was required for Vg endocytosis in the silkworm; loss of EndoA or overexpression of miR-2834 significantly reduced egg numbers in virgin moths. In addition, accumulation of miR-2834 resulted in pupal and adult deformation and reduced fecundity in females. The expression of Vg, 30-kDa (30K) protein, and egg-specific protein (Esp) decreased after knockdown of EndoA or overexpression of miR-2834, while knockdown of miR-2834 had an opposite effect on the expression of Vg, 30K protein gene, and Esp. These results suggest that the lncR26319-miR-2834-EndoA axis contributes to the endocytic activity in the Vg uptake and leads to the normal progression of oogenesis in the silkworm. Thus, miR-2834 and EndoA are crucial for female reproduction and could be potential targets for new pest management strategies in lepidopterans.
Topics: Female; Animals; Bombyx; Oogenesis; Vitellogenins; Oocytes; MicroRNAs; Insect Proteins
PubMed: 35612298
DOI: 10.1111/1744-7917.13082 -
Frontiers in Physiology 2022Insect life cycle is coordinated by hormones and their downstream effectors. Krüppel homolog1 (Kr-h1) is one of the crucial effectors which mediates the actions of the... (Review)
Review
Insect life cycle is coordinated by hormones and their downstream effectors. Krüppel homolog1 (Kr-h1) is one of the crucial effectors which mediates the actions of the two critical hormones of insects, the juvenile hormone (JH) and 20-hydroxyecdysone (20E). It is a transcription factor with a DNA-binding motif of eight CH zinc fingers which is found to be conserved among insect orders. The expression of is fluctuant during insect development with high abundance in juvenile instars and lower levels in the final instar and pupal stage, and reappearance in adults, which is governed by the coordination of JH, 20E, and miRNAs. The dynamic expression pattern of is closely linked to its function in the entire life of insects. Over the past several years, accumulating studies have advanced our understanding of the role of during insect development. It acts as a universal antimetamorphic factor in both hemimetabolous and holometabolous species by directly inhibiting the transcription of 20E signaling genes () and (), and steroidogenic enzyme genes involved in ecdysone biosynthesis. Meanwhile, it promotes vitellogenesis and ovarian development in the majority of studied insects. In addition, Kr-h1 regulates insect behavioral plasticity and caste identity, neuronal morphogenesis, maturation of sexual behavior, as well as embryogenesis and metabolic homeostasis. Hence, Kr-h1 acts as a cornerstone regulator in insect life.
PubMed: 35574485
DOI: 10.3389/fphys.2022.905441 -
Scientific Reports Apr 2022With the expansion and diversification of global aquaculture, efforts continue to develop new bio-technologies for assisted reproduction in species that present...
With the expansion and diversification of global aquaculture, efforts continue to develop new bio-technologies for assisted reproduction in species that present reproductive dysfunctions. Flathead grey mullet (Mugil cephalus) males held in intensive conditions in the Mediterranean region do not produce fluent milt and most females are arrested at previtellogenesis. The weekly injections of recombinant follicle stimulating hormone (rFsh) and luteinizing hormone (rLh) induced and completed vitellogenesis in treated females (n = 21), and treated males produced fluent sperm (n = 9). The application of a priming dose of 30 µg kg rLh and resolving dose of 40 mg kg Progesterone, or priming and resolving doses of 30 µg kg rLh, resulted in the induction of maturation, ovulation, and spontaneous spawns with a spawning success of the 85% (8 of 9 females) and 100% (n = 6), respectively. The eggs collected had 63 ± 21% fertilization with embryo development and 58 ± 23% hatching. In comparison, control individuals did not show advances in gonadal development and did not produce fluent sperm. The present results confirm the possibility of controlling oogenesis from previtellogenesis to the completion of maturation and fertilised tank spawning using exclusively rFsh and rLh in a teleost species.
Topics: Animals; Female; Follicle Stimulating Hormone; Humans; Luteinizing Hormone; Male; Progesterone; Recombinant Proteins; Reproduction; Smegmamorpha
PubMed: 35449146
DOI: 10.1038/s41598-022-10371-0