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FASEB Journal : Official Publication of... Jan 2019In addition to preventing insect metamorphosis, juvenile hormone (JH) is known to stimulate aspects of insect reproduction. However, the molecular mechanisms of JH...
In addition to preventing insect metamorphosis, juvenile hormone (JH) is known to stimulate aspects of insect reproduction. However, the molecular mechanisms of JH action in insect reproduction remain largely unknown. By reanalyzing the transcriptomic data from adults and other developmental stages of the migratory locust Locusta migratoria, we identified a gene coding for Kazal-type protease inhibitor, previously named Greglin. Greglin is specifically expressed in adult females and most abundant in the fat body and ovaries. Interestingly, Greglin is among the top 3 of highly expressed genes in adult female locusts, after 2 vitellogenin ( Vg) genes. Greglin is induced by JH and expressed at remarkably high levels in the vitellogenic stage. Knockdown of Greglin in adult female locusts results in accelerated degradation of serine protease substrate and significantly reduced levels of Greglin protein in hemolymph and ovaries. The consequent phenotypes include blocked oocyte maturation, arrested ovarian growth and shrunken follicular epithelium, as well as declines in egg number and hatchability. The data provide the first evidence, to our knowledge, that JH-dependent Greglin is involved in locust vitellogenesis and oocyte maturation likely by protecting vitellogenesis and other forms of yolk precursors from proteolysis. The result offers new insights into the regulation of JH and function of protease inhibitors in insect vitellogenesis, oocyte maturation and fecundity.-Guo, W., Wu, Z., Yang, L., Cai, Z., Zhao, L., Zhou, S. Juvenile hormone-dependent Kazal-type serine protease inhibitor Greglin safeguards insect vitellogenesis and egg production.
Topics: Amino Acid Sequence; Animals; Female; Gene Knockdown Techniques; Grasshoppers; Juvenile Hormones; Male; Ovum; Proteolysis; Sequence Homology, Amino Acid; Substrate Specificity; Transcriptome; Trypsin Inhibitor, Kazal Pancreatic; Vitellogenesis
PubMed: 30063437
DOI: 10.1096/fj.201801068R -
Biology Letters Dec 2022Optimistic and pessimistic cognitive biases have been described in many animals and are related to the perceived valence of the environment. We, therefore, hypothesize...
Optimistic and pessimistic cognitive biases have been described in many animals and are related to the perceived valence of the environment. We, therefore, hypothesize that such cognitive bias can be adaptive depending on environmental conditions. In reward-rich environments, an optimistic bias would be favoured, whereas in harsh environments, a pessimistic one would thrive. Here, we empirically investigated the potential adaptive value of such bias using zebrafish as a model. We first phenotyped female zebrafish in an optimistic/pessimistic axis using a previously validated judgement bias assay. Optimistic and pessimistic females were then exposed to an unpredictable chronic stress protocol for 17 days, after which fish were euthanized and the sectional area of the different ovarian structures was quantified in both undisturbed and stressed groups. Our results show that zebrafish ovarian development responded to chronic stress, and that judgement bias impacted the relative area of the vitellogenic developmental stage, with pessimists showing higher vitellogenic areas as compared with optimists. These results suggest that pessimism maximizes reproductive investment, through increased vitellogenesis, indicating a relationship between cognitive bias and life-history organismal decisions.
Topics: Animals; Female; Zebrafish; Pessimism; Judgment; Cognition; Bias
PubMed: 36541092
DOI: 10.1098/rsbl.2022.0232 -
General and Comparative Endocrinology Mar 2020Reproduction is energetically expensive and investing in this life history trait is likely accompanied by significant changes in physiological activity. Investment...
Reproduction is energetically expensive and investing in this life history trait is likely accompanied by significant changes in physiological activity. Investment strategy necessary for achieving reproductive success in reptiles can vary with reproductive form and pattern, potentiating different consequences for competing fitness-related traits such as those key to survival. The goal of this study was to assess if and how energetic state (i.e., energy metabolites) and self-maintenance (i.e., immunocompetence) are hormonally modulated across reproductive contexts in an oviparous, parthenogenetic lizard, the Colorado Checkered Whiptail Aspidoscelis neotesselata. Here blood plasma samples were collected from lizards within the US Army Fort Carson Military Installation near Colorado Springs, CO, USA, during seasons of reproductive activity (i.e., June) and inactivity (i.e., August). Measures of reproductive (i.e., estradiol) and energy-mobilizing (i.e., corticosterone) hormones, energy metabolites (i.e., glucose, triglycerides, and free glycerol), and innate immunity (i.e., bactericidal ability) were compared by season and reproductive stage. Levels of energy metabolites and bactericidal ability were compared to levels of E and CORT. Bactericidal ability was also compared to levels of energy metabolites. Corticosterone and glucose levels were lower during the reproductive season while triglyceride levels and bactericidal ability were higher, but both estradiol and free glycerol levels did not differ between seasons. Throughout vitellogenesis, corticosterone and glucose levels as well as bactericidal ability did not differ, but estradiol levels were higher during early and mid-stage and both triglyceride and free glycerol levels were lower during gravidity. Corticosterone levels were negatively associated with circulating triglycerides and bactericidal ability, but were not related to glucose nor free glycerol levels. Estradiol levels were positively associated with free glycerol levels and bactericidal ability, but were not related to glucose nor triglyceride levels. Finally, bactericidal ability was negatively associated with glucose, but positively associated with triglycerides. Differences in energetic state and immunocompetence are thus reflected by shifts in hormone secretion across reproductive investment. These findings provide partial support for the hypothesis that energetic state is differentially regulated by steroid hormones to afford reproduction, potentially at the cost of future survival.
Topics: Animals; Corticosterone; Energy Metabolism; Estradiol; Female; Gonadal Steroid Hormones; Immunocompetence; Lizards; Male; Oviparity; Parthenogenesis; Reproduction; Seasons; Vitellogenesis
PubMed: 31866306
DOI: 10.1016/j.ygcen.2019.113372 -
Invertebrate Neuroscience : IN Jun 2017The neuroendocrine system of insects, including the presence of the main neuroactive compounds, and their role in ontogenesis are probably best understood of all the... (Review)
Review
The neuroendocrine system of insects, including the presence of the main neuroactive compounds, and their role in ontogenesis are probably best understood of all the arthropods. Development, metamorphosis, the maturation of the gonads, vitellogenesis and egg production are regulated by hormones (juvenile hormones, ecdysteroids) and neuropeptides. However, knowledge about their presence and functions in spiders is fragmentary. In this paper, we present a summary of the current data about the juvenile hormones, ecdysteroids and neuropeptides in selected groups of arthropods, with particular emphasis on spiders. This is the first article that takes into account the occurrence, action and role of hormones and neuropeptides in spiders. In addition, the suggestions for possible ways to study these compounds in Araneomorphae spiders are unique and cannot be found in the arachnological literature.
Topics: Animals; Ecdysteroids; Insecta; Juvenile Hormones; Neuropeptides; Reproduction; Sexual Behavior, Animal; Species Specificity; Spiders
PubMed: 28421370
DOI: 10.1007/s10158-017-0197-8 -
Frontiers in Endocrinology 2023Bursicon, a neuropeptide hormone comprising two subunits-bursicon (burs) and partner of burs (pburs), belongs to the cystine-knot protein family. Bursicon heterodimers...
Bursicon, a neuropeptide hormone comprising two subunits-bursicon (burs) and partner of burs (pburs), belongs to the cystine-knot protein family. Bursicon heterodimers and homodimers bind to the lucine-rich G-protein coupled receptor (LGR) encoded by s to regulate multiple physiological processes in arthropods. Notably, these processes encompass the regulation of female reproduction, a recent revelation in . In this study we investigated the role of burs/pburs/rickets in mediating female vitellogenesis and reproduction in a hemipteran insect, the whitefly, . Our investigation unveiled a synchronized expression of and , with their transcripts persisting detectable in the days following eclosion. RNAi-mediated knockdown of , or significantly suppressed the transcript levels of () and in the female whiteflies. These effects also impaired ovarian maturation and female fecundity, as evidenced by a reduction in the number of eggs laid per female, a decrease in egg size and a decline in egg hatching rate. Furthermore, knockdown of , or led to diminished juvenile hormone (JH) titers and reduced transcript level of . However, this impact did not extend to genes in the insulin pathway or target of rapamycin pathway, deviating from the results observed in . Taken together, we conclude that burs/pburs/rickets regulates the vitellogenesis and reproduction in the whiteflies by coordinating with the JH signaling pathway.
Topics: Animals; Female; Hemiptera; Invertebrate Hormones; Juvenile Hormones; Vitellogenesis; Neuropeptides; Rickets
PubMed: 37854192
DOI: 10.3389/fendo.2023.1277439 -
Zoological Science Oct 2021Vitellogenesis in oviparous vertebrates is a critical marker of the restart of seasonal reproductive activity. During this process of multihormonal regulation, females...
Vitellogenesis in oviparous vertebrates is a critical marker of the restart of seasonal reproductive activity. During this process of multihormonal regulation, females allocate a considerable amount of organic and mineral reserves to the synthesis of yolk, with changes in their plasma values. In this work, we determined plasma levels of various metabolites and steroid hormones throughout the reproductive cycle in females of who developed vitellogenic and non-vitellogenic follicular cycles. We worked for two consecutive years with 20 adult females from the Experimental Hatchery of the Facultad de Agronomía y Zootecnia of the Universidad Nacional de Tucumán. Values of metabolites: glucose, triglycerides, cholesterol, calcium, phosphorus, albumin, total proteins, and hormones: estradiol, progesterone, and testosterone, were determined during the following stages of the annual cycle: hibernation, hibernation emergence, courtship-mating, oviposition, and incubation. Vitellogenic females showed significantly higher plasma levels of triglycerides, calcium, phosphorus, and albumin than non-vitellogenic females, mainly in the courtship-mating stage (advanced vitellogenesis). In contrast, annual cholesterol averages were lower in vitellogenic females. Glucose showed changes throughout the annual cycle regardless of the vitellogenic condition. Total proteins plasma levels had very few fluctuations during the cycle. Among the hormones studied, only testosterone showed differences related to vitellogenic condition, with higher levels in non-vitellogenic females during the entire reproductive cycle. The knowledge of these changes associated with vitellogenesis will improve zootechnical management and will allow optimizing the reproductive efficiency of lizards in captivity.
Topics: Animals; Cholesterol; Estradiol; Female; Lizards; Ovarian Follicle; Progesterone; Reproduction; Testosterone; Triglycerides; Vitellogenesis
PubMed: 34664921
DOI: 10.2108/zs210013 -
Results and Problems in Cell... 2019Even though tardigrades have been known since 1772, their phylogenetic position is still controversial. Tardigrades are regarded as either the sister group of... (Review)
Review
Even though tardigrades have been known since 1772, their phylogenetic position is still controversial. Tardigrades are regarded as either the sister group of arthropods, onychophorans, or onychophorans plus arthropods. Furthermore, the knowledge about their gametogenesis, especially oogenesis, is still poor and needs further analysis. The process of oogenesis has been studied solely for several eutardigradan species. Moreover, the spatial organization of the female germ-line clusters has been described for three species only. Meroistic ovaries characterize all analyzed species. In species of the Parachela, one cell per germ-cell cluster differentiates into the oocyte, while the remaining cells become the trophocytes. In Apochela several cells in the cluster differentiate into oocytes. Vitellogenesis is of a mixed type. The eggs are covered with the egg capsule that is composed of two shells: the thin vitelline envelope that adheres to the oolemma and the thick three-layered chorion. Chorion is formed as a first followed by vitelline envelope. Several features related to the oogenesis and structure of the ovary confirm the hypothesis that tardigrades are the sister group rather for arthropods than for onychophorans.
Topics: Animals; Female; Oocytes; Oogenesis; Ovary; Phylogeny; Tardigrada
PubMed: 31598869
DOI: 10.1007/978-3-030-23459-1_20 -
Insects Oct 2021Silkworm larval-pupal metamorphosis and the first half of pupal-adult development occur during oogenesis from previtellogenesis to vitellogenesis and include two peaks...
Silkworm larval-pupal metamorphosis and the first half of pupal-adult development occur during oogenesis from previtellogenesis to vitellogenesis and include two peaks of the hemolymph ecdysteroid titer. Moreover, a rise in 20-hydroxyecdysone titer in early pupae can trigger the first major transition from previtellogenesis to vitellogenesis in silkworm oogenesis. In this study, we first investigated the expression patterns of 66 maternal genes in the ovary at the wandering stage. We then examined the developmental expression profiles in six time-series samples of ovaries or ovarioles by reverse transcription-quantitative PCR. We found that the transcripts of 22 maternal genes were regulated by 20-hydroxyecdysone in the isolated abdomens of the pupae following a single injection of 20-hydroxyecdysone. This study is the first to determine the relationship between 20-hydroxyecdysone and maternal genes during silkworm oogenesis. These findings provide a basis for further research into the embryonic development of .
PubMed: 34821770
DOI: 10.3390/insects12110969 -
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 -
Acta Tropica Apr 2016The reproductive success of all oviparous species depends on vitellogenin (Vg) biosynthesis and its accumulation in the developing oocytes. The expression levels of two...
The reproductive success of all oviparous species depends on vitellogenin (Vg) biosynthesis and its accumulation in the developing oocytes. The expression levels of two Vg genes (Vg1 and Vg2) were analyzed by qPCR and western blot in fat body and ovaries of adult females, at different times after ecdysis (pre-vitellogenic phase) and after blood feeding of females (vitellogenic phase). Vg genes were also evaluated in fat bodies of adult males as well as in female fifth instar nymphs. No trace of Vg mRNA was detected in adult males or in nymphs. Vg1 and Vg2 were expressed in the fat bodies and ovaries of adult females. The Vg genes start to be expressed slightly in both tissues of adult females during pre-vitellogenesis. After blood feeding, Vg1 and Vg2 were up regulated and significant levels of Vg transcripts as well as protein expression were observed in fat bodies sampled throughout vitellogenesis. During this period however, the distribution patterns of Vg1 and Vg2 transcripts showed two peaks around early and advanced vitellogenesis (days 4 and 12 post-feeding, respectively). In the ovaries, levels of mRNAs increased from the day 10 post-blood feeding onwards. In addition, the immunofluorescence assays showed a strong signal for vitellin in the yolk bodies of terminal follicles of vitellogenic females. The involvement of fat body and ovary in the synthesis of Vg suggests different roles of Vgs in supporting the growth of oocytes.
Topics: Animals; Chagas Disease; Female; Insect Vectors; Male; South America; Southwestern United States; Triatoma; Vitellogenesis; Vitellogenins
PubMed: 26772448
DOI: 10.1016/j.actatropica.2016.01.004