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Frontiers in Insect Science 2024In insects and other animals, nutrition-mediated behaviors are modulated by communication between the brain and peripheral systems, a process that relies heavily on the... (Review)
Review
In insects and other animals, nutrition-mediated behaviors are modulated by communication between the brain and peripheral systems, a process that relies heavily on the insulin/insulin-like growth factor signaling pathway (IIS). Previous studies have focused on the mechanistic and physiological functions of insulin-like peptides (ILPs) in critical developmental and adult milestones like pupation or vitellogenesis. Less work has detailed the mechanisms connecting ILPs to adult nutrient-mediated behaviors related to survival and reproductive success. Here we briefly review the range of behaviors linked to IIS in insects, from conserved regulation of feeding behavior to evolutionarily derived polyphenisms. Where possible, we incorporate information from and other model species to describe molecular and neural mechanisms that connect nutritional status to behavioral expression via IIS. We identify knowledge gaps which include the diverse functional roles of peripheral ILPs, how ILPs modulate neural function and behavior across the lifespan, and the lack of detailed mechanistic research in a broad range of taxa. Addressing these gaps would enable a better understanding of the evolution of this conserved and widely deployed tool kit pathway.
PubMed: 38638680
DOI: 10.3389/finsc.2024.1360320 -
BioRxiv : the Preprint Server For... Nov 2023Mosquitoes such as must consume a blood meal for the nutrients necessary for egg production. Several transcriptome and proteome changes occur post blood meal that...
Mosquitoes such as must consume a blood meal for the nutrients necessary for egg production. Several transcriptome and proteome changes occur post blood meal that likely corresponds with codon usage alterations. Transfer RNA (tRNA) is the adapter molecule that reads messenger RNA (mRNA) codons to add the appropriate amino acid during protein synthesis. Chemical modifications to tRNA enhance codons' decoding, improving the accuracy and efficiency of protein synthesis. Here, we examined tRNA modifications and transcripts associated with the blood meal and subsequent periods of vitellogenesis in . More specifically, we assessed tRNA transcript abundance and modification levels in the fat body at critical times post blood-feeding. Based on a combination of alternative codon usage and identification of particular modifications, we identified that increased transcription of tyrosine tRNAs is likely critical during the synthesis of egg yolk proteins in the fat body following a blood meal. Altogether, changes in both the abundance and modification of tRNA are essential factors in the process of vitellogenin production after blood-feeding in mosquitoes.
PubMed: 38076852
DOI: 10.1101/2023.11.29.569187 -
General and Comparative Endocrinology Feb 2024The Pacific halibut (Hippoglossus stenolepis) is a large migratory demersal flatfish species that occupies a top trophic role in the North Pacific Ocean and Bering Sea...
The Pacific halibut (Hippoglossus stenolepis) is a large migratory demersal flatfish species that occupies a top trophic role in the North Pacific Ocean and Bering Sea ecosystems, where it also supports various fisheries. As a first attempt to characterize the endocrine mechanisms driving sexual maturation in this important species, we collected pituitary, ovarian and blood samples from Pacific halibut females captured in the wild that were classified histologically into various female developmental stages. We conducted gene expression analyses of gonadotropin beta subunits in the pituitary and observed that mRNA expression levels of fshb gradually increased throughout vitellogenesis, remained elevated until before ovulation and declined after spawning. In contrast, the mRNA expression levels of lhb markedly increased during oocyte maturation and remained elevated until after spawning. Ovarian mRNA expression levels of the gonadotropin receptor genes fshr and lhr peaked during oocyte maturation and before spawning, respectively, immediately following the developmental stage at which pituitary fshb and lhb mRNA expression first reached maximum levels. The ovarian gene expression patterns of steroidogenic enzyme genes cyp19a1 and hsd20b2 paralleled those of fshr and lhr, respectively. Testosterone and 17β-estradiol (E) plasma levels increased concomitantly with fshr and cyp19a1 mRNA expression levels, and vitellogenin plasma levels increased throughout vitellogenesis and reached maximum levels prior to spawning. These results are consistent with the notion that in female Pacific halibut, as in other teleosts, vitellogenesis and oocyte maturation and ovulation are likely under the control of pituitary gonadotropic hormones Fsh and Lh, respectively.
Topics: Animals; Female; Flounder; Ecosystem; Gonadotropins, Pituitary; Gonadotropins; RNA, Messenger
PubMed: 38101488
DOI: 10.1016/j.ygcen.2023.114425 -
Nature Communications Feb 2022Vitellogenesis (yolk accumulation) begins upon eclosion and continues through the process of sexual maturation. Upon reaching sexual maturity, vitellogenesis is placed...
Vitellogenesis (yolk accumulation) begins upon eclosion and continues through the process of sexual maturation. Upon reaching sexual maturity, vitellogenesis is placed on hold until it is induced again by mating. However, the mechanisms that gate vitellogenesis in response to developmental and reproductive signals remain unclear. Here, we have identified the neuropeptide allatostatin-C (AstC)-producing neurons that gate both the initiation of vitellogenesis that occurs post-eclosion and its re-initiation post-mating. During sexual maturation, the AstC neurons receive excitatory inputs from Sex Peptide Abdominal Ganglion (SAG) neurons. In mature virgin females, high sustained activity of SAG neurons shuts off vitellogenesis via continuous activation of the AstC neurons. Upon mating, however, Sex Peptide inhibits SAG neurons, leading to deactivation of the AstC neurons. As a result, this permits both JH biosynthesis and the progression of vitellogenesis in mated females. Our work has uncovered a central neural circuit that gates the progression of oogenesis.
Topics: Animals; Animals, Genetically Modified; Drosophila Proteins; Drosophila melanogaster; Female; Neurons; Oocytes; Sexual Behavior, Animal; Somatostatin; Vitellogenesis
PubMed: 35181671
DOI: 10.1038/s41467-022-28592-2 -
Journal of Morphology Apr 2017The identification of the elasmobranch secondary ovarian follicles and their function can be challenging and the inconsistent use of terminology derived from other taxa... (Review)
Review
The identification of the elasmobranch secondary ovarian follicles and their function can be challenging and the inconsistent use of terminology derived from other taxa is a matter of ongoing debate. In this study, the available information on the histology of the elasmobranch secondary ovarian follicles derived from atresia (preovulatory follicles) or ovulation (postovulatory follicles) is reviewed highlighting their morphology and steroidogenic capacity. Based on this literature review, the ovarian follicles of the Australian sharpnose shark Rhizoprionodon taylori were classified according to their preovulatory or postovulatory origin. Two types of secondary follicles originating from atresia of developing follicles (atretic previtellogenic follicles) and ripe follicles (atretic vitellogenic follicles), and one type of postovulatory follicle were identified throughout the reproductive year of this species. Morphological similarities of the elasmobranch secondary ovarian follicles and their variations in different species denote the difficulty to classify them. Given the multiple origins of ovarian follicles, their poorly understood functions and capacity to supply steroids, visual identification of these structures and the use of terminology derived from mammalian and other vertebrate studies (with the exception of the corpora lutea as a temporary endocrine gland) is not advisable. J. Morphol. 278:486-499, 2017. © 2017 Wiley Periodicals, Inc.
Topics: Animals; Female; Follicular Atresia; Oocytes; Ovarian Follicle; Ovulation; Sharks; Vitellogenesis
PubMed: 28165147
DOI: 10.1002/jmor.20644 -
General and Comparative Endocrinology Sep 2020The African bonytongue (Heterotis niloticus) is an excellent candidate for fish farming because it has outstanding biological characteristics and zootechnical...
Identification and structural characterization of the factors involved in vitellogenesis and its regulation in the African Osteoglossiforme of aquacultural interest Heterotis niloticus (Cuvier, 1829).
The African bonytongue (Heterotis niloticus) is an excellent candidate for fish farming because it has outstanding biological characteristics and zootechnical performances. However, the absence of sexual dimorphism does not favor its reproduction in captivity or the understanding of its reproductive behavior. Moreover, no molecular data related to its reproduction is yet available. This study therefore focuses on the structural identification of the different molecular actors of vitellogenesis expressed in the pituitary gland, the liver and the ovary of H. niloticus. A transcriptomic approach based on de novo RNA sequencing of the pituitary gland, ovary and liver of females in vitellogenesis led to the creation of three transcriptomes. In silico analysis of these transcriptomes identified the sequences of pituitary hormones such as prolactin (PRL), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and their ovarian receptors (PRLR, FSHR, LHR). In the liver and ovary, estrogen receptors (ER) beta and gamma, liver vitellogenins (VtgB and VtgC) and their ovarian receptors (VLDLR) were identified. Finally, the partial transcript of an ovarian Vtg weakly expressed compared to hepatic Vtg was identified based on structural criteria. Moreover, a proteomic approach carried out from mucus revealed the presence of one Vtg exclusively in females in vitellogenesis. In this teleost fish that does not exhibit sexual dimorphism, mucus Vtg could be used as a sexing biomarker based on a non-invasive technique compatible with the implementation of experimental protocols in vivo.
Topics: Amino Acid Sequence; Animals; Aquaculture; Base Sequence; Computer Simulation; Female; Fishes; Liver; Mucus; Ovary; Prolactin; Protein Structure, Secondary; Receptors, Cell Surface; Vitellogenesis; Vitellogenins
PubMed: 32535172
DOI: 10.1016/j.ygcen.2020.113532 -
Theriogenology Mar 2022Inducing maturation of the ovaries to enable the production of good-quality eggs is critical for the successful artificial breeding of Anguilla japonica. During the...
Inducing maturation of the ovaries to enable the production of good-quality eggs is critical for the successful artificial breeding of Anguilla japonica. During the spawning season, however, the ovaries of A. japonica have been found to develop into asynchronous clutches, impeding the success of artificial breeding on a commercial scale. The dynamic molecular regulation of follicular development in the same individual was assessed by transcriptome analysis of the five stages of follicles, the pre-vitellogenic, early vitellogenic, midvitellogenic, late vitellogenic, and migratory nucleus stages in artificial maturing A. japonica. Comparisons across these developmental stages identified a total of 19,298 differentially expressed transcripts (DETs). Short time-series expression miner analysis across these DETs revealed four significant expression profiles. Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses found that some of the significantly enriched biological processes and metabolic pathways included those related to steroid hormone biosynthesis (cyp11a1, cyp17a1, cyp17a2, hsd17b1, and hsd17b12), cargo receptor activity (vtgr and vldlr), meiosis and ovulation (pgrs and mPRγ), hydration (cts and aqp1), and egg coat formation (zp). These genes and pathways were associated with serum 17β-estradiol concentrations and morphological changes. The levels of hsd17b12 and mPRγ mRNAs were much higher during the migratory nucleus stage, suggesting their respective involvement in the biosynthesis and functional pathway of the maturation-inducing steroid 17α,20β-dihydroxy-4-pregnen-3-one. The gene subtypes aqp1b and ctsd may regulate water influx into oocytes and yolk protein proteolysis, respectively. To our knowledge, the present study is the first to describe combined transcriptome profiling of asynchronously developing follicles in the same individual. The findings suggest that steroid hormone synthesis and nutrient absorption in follicular somatic cells play important roles during follicular development and maturation, despite the same external physiological surroundings.
Topics: Anguilla; Animals; Female; Gene Expression Profiling; Oocytes; Ovarian Follicle; Ovary; Transcriptome; Vitellogenesis
PubMed: 34990963
DOI: 10.1016/j.theriogenology.2021.12.031 -
Biology of Reproduction Aug 2023Insulin-like growth factor 1 (Igf1) is known to promote ovarian maturation by interacting with other hormones. However, the limited research on the role of Igf1 in the...
Insulin-like growth factor 1 (Igf1) is known to promote ovarian maturation by interacting with other hormones. However, the limited research on the role of Igf1 in the energy metabolism supply of gonads has hindered further exploration. To explore the role of Igf1 in gonadal development of silver pomfret, we analyzed the expression levels and the localization of igf1 mRNA and protein during testicular and ovarian development of silver pomfret. The results of the study showed upregulation of Igf1 in the critical period of vitellogenesis and sperm meiosis, which was found to be mainly expressed in the somatic cells of the gonads. Upon adding E2 and Igf1 to cultured gonadal tissues, the expression of energy-related genes was significantly increased, along with the E2-enhanced effect of Igf1 in the testis. Importantly, stimulation of both ovaries and testes with E2 and Igf1 led to a remarkable increase in the expression of vitellogenesis and meiosis-related genes. Therefore, we conclude that Igf1 promotes vitellogenesis and sperm meiosis by regulating gonadal energy production. Moreover, the expression of Igf1 in gonads is significantly regulated by E2. These findings provide new insights for the research of Igf1 in fish breeding, thus allowing the regulation of energy metabolism between growth and reproduction for successful reproductive outcomes.
Topics: Animals; Female; Male; Insulin-Like Growth Factor I; Semen; Gonads; Ovary; Perciformes; Energy Metabolism
PubMed: 37228017
DOI: 10.1093/biolre/ioad058 -
Comparative Biochemistry and... Sep 2020When successive stages of an organism's life-history overlap, conflicts and trade-offs can emerge due to competition among physiological pathways. For example, long...
When successive stages of an organism's life-history overlap, conflicts and trade-offs can emerge due to competition among physiological pathways. For example, long periods of sustained locomotion in migrating birds are supported by the androgenic up-regulation of aerobic factors, such as new red blood cell production and hematocrit. However, towards the end of migration, many female birds begin up-regulating 17ß-estradiol (E) to support vitellogenesis and egg production, but E secretion is known to have suppressive effects on red blood cell production (anti-erythropoiesis). We explored potential trade-offs between factors related to aerobic performance (hematocrit, reticulocyte index) and the expression of factors related to E-mediated vitellogenesis (i.e. yolk precursor production) in female macaroni penguins (Eudyptes chrysolophus), a species in which the physiologies controlling egg production and migratory activity run simultaneously (e.g. females experience a migratory conflict). We collected blood samples from penguins immediately upon their return to the colony, prior to egg laying. Hematocrit was elevated when the penguins returned to the colony (50.05% ± 3.40 SD), which is similar to pre-laying values observed in other migratory bird species. Furthermore, mean reticulocyte levels were elevated (34.87% ± 2.34), which is the highest level yet recorded in birds. Similarly, both plasma vitellogenin and yolk-targeted very low density lipoprotein levels were upregulated (2.30 ± 0.06 μg Zn ml, and 9.70 ± 0.19 mmol l, respectively), indicating that penguins were reproductively active and producing eggs during migration and upon arrival on land. As predicted, a negative relationship between hematocrit and plasma vitellogenin was found, but we found no evidence to suggest that birds were experiencing reproductive anemia. Alternatively, we attribute the negative relationship to a hemodilution effect of yolk precursor secretion into circulation. It appears that female macaroni penguins are able to preserve hematocrit levels and new red blood cell production when migratory activity overlaps with reproductive processes.
Topics: Androgens; Animal Migration; Animals; Estradiol; Female; Hematocrit; Oxygen Consumption; Reproduction; Spheniscidae; Vitellogenins
PubMed: 32535235
DOI: 10.1016/j.cbpa.2020.110742 -
Frontiers in Endocrinology 2021The role G-protein coupled estrogen receptor (GPER) plays in vertebrate reproduction remains controversial. To investigate GPER's reproductive role, we generated a gper...
The role G-protein coupled estrogen receptor (GPER) plays in vertebrate reproduction remains controversial. To investigate GPER's reproductive role, we generated a gper zebrafish mutant line ( ) using TALENs. Gper mutant females exhibited reduced fertility with a 40.85% decrease in embryo production which was associated with a significant decrease in the number of Stage V (730-750 μm) ovulated oocytes. Correspondingly, the number of early vitellogenic follicles (Stage III, 400-450 µm) in ovaries was greater than that in wildtypes (), suggesting that subsequent follicle development was retarded in the fish. Moreover, plasma vitellogenin levels were decreased in females, and epidermal growth factor receptor (Egfr) expression was lower in Stage III vitellogenic oocytes than in counterparts. However, hepatic nuclear estrogen receptor levels were not altered, and estrogen levels were elevated in ovarian follicles. These results suggest that Gper is involved in the control of ovarian follicle development regulation of vitellogenesis and Egfr expression in zebrafish.
Topics: Animals; Cell Membrane; ErbB Receptors; Estrogens; Female; Fertility; Fishes; Metabolomics; Mutation; Oocytes; Ovarian Follicle; Ovulation; Receptors, Estrogen; Receptors, G-Protein-Coupled; Vitellogenesis; Vitellogenins; Zebrafish; Zebrafish Proteins
PubMed: 33790865
DOI: 10.3389/fendo.2021.637691