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Simple Summary: Gonadotropin-releasing hormone (GnRH) is an important regulator in the process of reproduction in vertebrates through the hypothalamic-pituitary-gonadal (HPG) axis. Adipokinetic hormone/corazonin-related peptide (ACP) is a GnRH structurally related peptide that is extensively present in arthropods. In insects, ACP is involved in lipid metabolism, but its function in crustaceans remains unclear. This study identified ACP and its putative receptor in the mud crab Scylla paramamosain and further evaluated its possible role in ovarian development. Our results showed that ACP was mainly expressed in the follicle cells and showed that it played a stimulatory role in ovarian development. ACP signaling enhances vitellogenin (Vg) expression in the hepatopancreas, which is likely mediated by estradiol, and promotes vitellogenin uptake by oocytes by inducing Vg receptor expression. These findings provide new insights into the role of ACP signaling and hormonal regulation on reproduction in economically important crustaceans. In this study, we identified Sp-ACP and its putative receptor from the mud crab S. paramamosain and explored its potential role in ovarian development. RT-PCR results suggested Sp-ACP was extensively expressed in nervous tissues, the ovary, the middle gut, and the Y-organ, while Sp-ACPR was highly expressed in the ovary. The expression level of Sp-ACP in the ovary, eyestalk, and cerebral ganglia gradually increased during ovarian development, whereas its receptor exhibited an opposite expression pattern in the ovary. Immunofluorescence revealed that ACP was specifically localized in the follicle cells of the ovary. In vitro experiments showed that the expression of vitellogenin receptor (Sp-VgR) in the ovary was significantly increased by 4 and 6 h incubation of Sp-ACP (10 nM). In addition, 12 h injection of Sp-ACP significantly induced the levels of Sp-Vg in the hepatopancreas and Sp-VgR in the ovary, and hemolymph 17β-estradiol titer. Finally, it demonstrated that prolonged injection of Sp-ACP significantly increased the level of Vg and VgR expression, hemolymph 17β-estradiol titer, GSI, and the oocyte diameter. In conclusion, our results suggested that ACP is involved in the regulation of ovarian development of S. paramamosain, likely by inducing hepatopancreas Sp-Vg expression through estradiol and promoting the uptake of Vg by oocytes. [ABSTRACT FROM AUTHOR]

Simple Summary: Ticks, as obligate ectoparasites, pose significant health risks by transmitting pathogens to various hosts, including humans and livestock, resulting in diseases and economic losses. This study focuses on Haemaphysalis hystricis, a tick prevalent in Southeast Asia, which infests both wild and domestic animals, leading to severe health impacts like emaciation and growth stunting. The tick's life cycle, which includes stages from egg to adult, is crucial for understanding its development and for devising effective control strategies. This research aims to characterize protein expression in H. hystricis eggs throughout embryonic development using LC/MS/MS techniques. By identifying key proteins involved in egg development and metabolism, the study seeks to provide insights into tick embryogenesis and to identify potential targets for interventions that could disrupt tick reproduction and reduce the transmission of tick-borne diseases. Ultimately, the findings are expected to contribute to improving public health and animal husbandry practices by informing better tick management strategies. Tick eggs contain a series of proteins that play important roles in egg development. A thorough characterization of egg protein expression throughout development is essential for understanding tick embryogenesis and for screening candidate molecules to develop novel interventions. In this study, eggs at four developmental stages (0, 7, 14, and 21 incubation days) were collected, and their protein extraction was profiled using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). On the first day of egg protein extraction, protein bands from day-1 eggs were re-collected and subsequently analyzed using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The dynamic changes in forty egg proteins during development were further investigated using LC-parallel reaction monitoring (PRM)/MS analysis. A total of 108 transcripts were detected in day-1 eggs. Based on protein functions and families, these transcripts were classified into eight categories: transporters, enzymes, immunity and antimicrobial proteins, proteinase inhibitors, cytoskeletal proteins, heat shock proteins, secreted proteins, and uncharacterized proteins. Identification of the protein bands revealed that nine bands predominantly consisted of vitellogenin and vitellin-A, while other notable proteins included cathepsins and Kunitz domain-containing proteins. LC-PRM/MS analysis indicated that 28 transcripts increased significantly in abundance, including 13/18 enzymes, 1/1 antimicrobial peptide, 2/2 neutrophil elastase inhibitors, 3/4 vitellogenins, 3/3 heat shock proteins, 3/3 cytoskeletal proteins, 1/1 elongation factor-1, and 1/1 uncharacterized protein. Conversely, five transcripts showed a decrease significantly, including 1/1 Kunitz domain-containing protein, 2/6 aspartic proteases, and 2/5 serpins. This research provides a comprehensive overview of egg proteins and highlights the dynamic changes in protein expression during embryonic development, which may be pivotal for understanding protein functions and selecting potential candidates for further study. [ABSTRACT FROM AUTHOR]

Vitellogenesis is the most important process in animal reproduction, in which yolk proteins play a vital role. Among multiple yolk protein precursors, vitellogenin (Vtg) is a well-known major yolk protein (MYP) in most oviparous animals. However, the nature of MYP in the freshwater gastropod snail Biomphalaria glabrata remains elusive. In the current study, we applied bioinformatics, tissue-specific transcriptomics, ovotestis-targeted proteomics, and phylogenetics to investigate the large lipid transfer protein (LLTP) superfamily and ferritin-like family in B. glabrata. Four members of LLTP superfamily (BgVtg1, BgVtg2, BgApo1, and BgApo2), one yolk ferritin (Bg yolk ferritin), and four soma ferritins (Bg ferritin 1, 2, 3, and 4) were identified in B. glabrata genome. The proteomic analysis demonstrated that, among the putative yolk proteins, BgVtg1 was the yolk protein appearing in the highest amount in the ovotestis, followed by Bg yolk ferritin. RNAseq profile showed that the leading synthesis sites of BgVtg1 and Bg yolk ferritin are in the ovotestis (presumably follicle cells) and digestive gland, respectively. Phylogenetic analysis indicated that BgVtg1 is well clustered with Vtgs of other vertebrates and invertebrates. We conclude that, vitellogenin (BgVtg1), not yolk ferritin (Bg yolk ferritin), is the major yolk protein precursor in the schistosomiasis vector snail B. glabrata.

Insulin‐like peptides (ILPs) act as crucial reproductive neuropeptides in insects, regulating insect reproduction through the insulin signaling pathway (ISP). Our previous studies have found that the sublethal concentrations (LC1 and LC10) of lambda‐cyhalothrin (λCy) could induce severe reproductive toxicity in the lacewing, Chrysoperla sinica (Tjeder), but the toxicological mechanism remains unclear. This study discovered that λCy could inhibit CsILP transcription, leading to a decrease in insulin content and downregulation of C. sinica insulin receptor (CsInR) and C. sinica forkhead box O (CsFOXO) expression in ISP. Interference with CsILP expression resulted in downregulation of C. sinica vitellogenin (CsVg) and decreasing fecundity, while exogenous injection of bovine insulin promoted upregulation of CsVg expression and facilitated reproduction in female adults of C. sinica. Meanwhile, interference with FOXO of ILP downstream transcription factor could lead to downregulation of CsVg, hindering ovarian development and resulting in a decrease in egg production. However, exogenous injection of bovine insulin could remedy the effects caused by FOXO interference. In addition, ILP mediates juvenile hormone and 20‐hydroxyecdysone biosynthesis by acting on their synthetic regulatory enzymes and influences the signal transduction of the 2 reproductive endocrine hormones, thereby regulating the reproductive endocrine environment in C. sinica. In conclusion, λCy inhibits CsILP expression, leading to disorder of ISP, leading to the reduced fecundity of C. sinica. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that androgens are a potent driver of growth during late the primary stage of ovarian follicle development in teleosts. We have previously shown that the non-aromatizable androgen, 11-ketotestosterone (11-KT), both advances ovarian follicle growth in vivo and dramatically alters the primary growth ovarian transcriptome in coho salmon. Many of the transcriptomic changes pointed towards 11-KT driving process associated with the transition to a secondary growth phenotype. In the current study, we implanted previtellogenic early secondary growth coho salmon with cholesterol pellets containing 11-KT and performed RNA-Seq on ovarian tissue after 3 days in order to identify alterations to the ovarian transcriptome in early secondary growth. We identified 8,707 contiguous sequences (contigs) that were differentially expressed (DE) between control and 11-KT implanted fish and were able to collapse those to 3,853 gene-level IDs, more than a 3-fold more DE contigs than at the primary growth stage we reported previously. These contigs included genes encoding proteins involved in steroidogenesis, vitellogenin and lipid uptake, follicle stimulating hormone signaling, growth factor signaling, and structural proteins, suggesting androgens continue to promote previtellogenic secondary growth. [ABSTRACT FROM AUTHOR]

Panonychus citri is one of the most destructive pests in citrus orchards, exhibiting varying degrees of tolerance to numerous insecticides, such as spirodiclofen. To effectively manage pests, this study explores the response of P. citri to spirodiclofen stress from the perspectives of life history, enzymatic parameters, and reproduction. The effects of two concentrations (LC30 and LC50) of spirodiclofen on the biological parameters of P. citri were evaluated by the life table method. The results showed that the development duration, fecundity, oviposition days, and lifespan were shortened, though the pre-oviposition period of two treatments was prolonged in comparison with the control. A significant decrease was recorded in the net reproductive rate (R 0) and the mean generation time (T) for the two treatments. Nevertheless, the intrinsic rate of increase (r) and the rate of increase (λ) were not significantly affected in the LC30 treatment, whereas they declined in the LC50 treatment. The enzyme activity assay resulted in higher activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and carboxylesterase (CarE), among the treatments than the control. In contrast, the treatments recorded lower cytochromeP450 (CYP450) and Glutathione S-transferase (GST) activities than the control. Furthermore, the study detected that relative mRNA expression of Vitellogenin (Vg) and Vitellogenin receptor (VgR) for two treatments were lower than the control. In summary, two concentrations of spirodiclofen inhibited progeny growth and fecundity of P. citri. Additionally, the results of this study may support further research on tolerance of P. citri in response to spirodiclofen stress. [ABSTRACT FROM AUTHOR]

Vitellogenin (Vg) has been recognized as a co‐opted gene involved in social colonies where it is associated with reproduction in the queen and task transitions in workers. The Solenopsis invicta genome harbours four Vg genes, Vg1, Vg2, Vg3 and Vg4, and this study explored the regional expression of these genes in the brain and head of the worker caste in different subcaste and social contexts. Transcriptomic analyses of the worker brain while in the presence or absence of brood revealed differential expression of genes involved with social behaviours. Among these, we found higher expression of Vg2 and Vg3 in the brains of workers in the absence of brood. The influence of brood on expression of Vg between worker castes was also investigated. RT‐qPCR revealed higher expression of Vg in the head of workers in the absence of brood. Further studies demonstrated that Vg was also differentially expressed in the heads of workers conducting specific tasks and differing between subcastes. Nurses maintained higher Vg expression than foragers. We conclude worker Vg expression may be linked to the brood and/or nutritional state. Vg expression changes when workers are deprived of protein suggesting it is regulated by nutritional signalling and the presence of brood. [ABSTRACT FROM AUTHOR]

Phthalates, such as di-n-butyl phthalate (DBP) and di-isopentyl phthalate (DiPeP), are pollutants with a high potential for endocrine disruption. This study aimed to evaluate parameters of endocrine disruption in specimens of the Neotropical fish Rhamdia quelen exposed to DBP and DiPeP through their food. After 30 days of exposure, the fish were anesthetized and then euthanized, and blood, hypothalamus, liver, and gonads were collected. DBP caused statistically significant alterations in the serotoninergic system of males (5 and 25 ng/g) and females (5 ng/g) of R. quelen and it increased testosterone levels in females (25 ng/g). DiPeP significantly altered the dopaminergic system in females, reduced plasma estradiol levels (125 ng/g) and hepatic vitellogenin expression (25 ng/g), and changed the antioxidant system in gonads (125 ng/g). The results suggest that DBP and DiPeP may have different response patterns in females, with the former being androgenic and the latter being anti-estrogenic. These findings provide additional evidence regarding the molecular events involving DBP and DiPeP in the endocrine disruption potential in juvenile specimens of Rhamdia quelen. [ABSTRACT FROM AUTHOR]

Short neuropeptide F (sNPF) is a neuropeptide that widely distributed among arthropods. This neuropeptide has been proposed to play pleiotropic roles in insects, but its physiological functions in crustaceans are poorly understood. Here, we cloned the cDNA sequences of sNPF and its putative receptor (sNPFR) from the swimming crab, Portunus trituberculatus, and determined their possible roles during ovarian development. PtsNPF encodes three sNPF mature peptides with a conserved C-terminal "RLRFG" motif. All three PtsNPF peptides concentration-dependently activated PtsNPFR expressed in HEK293T cells, with EC50 values in the nanomolar range. PtsNPF and PtsNPFR transcripts showed a broad distribution among neural and non-neural tissues. During the ovarian development, expression of PtsNPF and PtsNPFR in hepatopancreas and ovary both increased to the highest levels at the late-vitellogenic stage, a period for rapid vitellogenesis. The in vitro experiments further showed that, among the three sNPF peptides, sNPF3 treatments can induce the vitellogenin (Vg) gene and protein levels in the hepatopancreas, as well as the Vg receptor (VgR) gene and protein levels and vitellogenin (Vn) deposition in the ovary. Opposing effects were observed for the dsPtsNPFR treatments, suggesting that PtsNPFR plays a role in the PtsNPF-mediated vitellogenesis. Additionally, it was found that the PtsNPF/PtsNPFR system can activate different second messengers species in hepatopancreas and ovary, suggesting it may act via different G proteins. [ABSTRACT FROM AUTHOR]

Summary: The purpose of this experiment was to explore the improvement of tussah pupa powder on the deterioration of pork batter emulsion gel by using proteomics, distribution of moisture, rheological properties and surface hydrophobicity. The results showed that the myosin decomposed as the heating temperature increased; as the increase of the addition proportion of tussah pupa powder at each sterilisation temperature point, compared to the control group, the pH of a pork batter emulsified gel showed a significant increased trend (P < 0.05); the low molecular weight proteins or formed oligomers of tussah pupa powder could be used as fillers to participate in the formation process of gel network; the vitellogenin of tussah pupa powder could form a 'skeleton' in the pork batter system; as the sterilisation temperature at 100 °C (30 min) and 110 °C (30 min), the surface hydrophobicity was the largest as the addition amount 2%. In short, the tussah pupae powder could improve the deterioration characteristics of the pork batter emulsified gel by influencing the pH, surface hydrophobicity and the formation of gel network of pork batter system. This research provided theoretical support for improving the process property of the meat products. [ABSTRACT FROM AUTHOR]

The insulin signaling (IIS) pathway plays a key role in the regulation of various physiological functions in animals. However, the involvement of IIS pathway in the reproduction of natural enemy insects remains enigmatic. Here, 3 key genes (named ClInR , ClPI3K , and ClAKT) related to IIS pathway were cloned from Cyrtorhinus lividipennis (Reuter) (Hemiptera: Miridae), an important natural enemy in the rice ecosystem. These 3 proteins had the typical features of corresponding protein families and shared high similarity with their respective homologs from the Hemipteran species. The ClInR , ClPI3K , and ClAKT were highly expressed in the adult stage. Tissue distribution analysis revealed that ClInR , ClPI3K , and ClAKT were highly expressed in the midgut and ovary of adults. Silencing of ClInR , ClPI3K , and ClAKT caused 92.1%, 72.1%, and 57.8% reduction in the expression of ClVg , respectively. Depletion of these 3 genes impaired vitellogenin synthesis and ovary development. Moreover, the fecundity in the dsInR, dsPI3K, and dsAKT injected females were 53.9%, 50.8%, and 48.5% lower than the control treatment, respectively. These results indicated that ClInR , ClPI3K , and ClAKT are of great importance for the reproduction of C. lividipennis. Our results advance the knowledge about the molecular mechanism of reproduction regulation in natural enemy insects. [ABSTRACT FROM AUTHOR]

Diaphorina citri serves as the primary vector for 'Candidatus Liberibacter asiaticus (CLas),' the bacterium associated with the severe Asian form of huanglongbing. CLas-positive D. citri are more fecund than their CLas-negative counterparts and require extra energy expenditure. Therefore, understanding the molecular mechanisms linking metabolism and reproduction is of particular importance. In this study, we found adipokinetic hormone (DcAKH) and its receptor (DcAKHR) were essential for increasing lipid metabolism and fecundity in response to CLas infection in D. citri. Knockdown of DcAKH and DcAKHR not only resulted in the accumulation of triacylglycerol and a decline of glycogen, but also significantly decreased fecundity and CLas titer in ovaries. Combined in vivo and in vitro experiments showed that miR-34 suppresses DcAKHR expression by binding to its 3' untranslated region, whilst overexpression of miR-34 resulted in a decline of DcAKHR expression and CLas titer in ovaries and caused defects that mimicked DcAKHR knockdown phenotypes. Additionally, knockdown of DcAKH and DcAKHR significantly reduced juvenile hormone (JH) titer and JH signaling pathway genes in fat bodies and ovaries, including the JH receptor, methoprene-tolerant (DcMet), and the transcription factor, Krüppel homolog 1 (DcKr-h1), that acts downstream of it, as well as the egg development related genes vitellogenin 1-like (DcVg-1-like), vitellogenin A1-like (DcVg-A1-like) and the vitellogenin receptor (DcVgR). As a result, CLas hijacks AKH/AKHR-miR-34-JH signaling to improve D. citri lipid metabolism and fecundity, while simultaneously increasing the replication of CLas, suggesting a mutualistic interaction between CLas and D. citri ovaries. [ABSTRACT FROM AUTHOR]

For this study, 240 adult healthy female zebrafish were divided into 12 tanks (20 fish per tank) and exposed to 0 (control, T0), 0.1 (T1), 1 (T2), and 10 (T3) mg/L synthesized polystyrene nanoplastics (PS-NPs, nanoplastics synthesized in the chemistry laboratory of the Faculty of Basic Sciences at Zabol University) for 4 weeks. At the end of the experiment, exposure to PS-NPs had no significant effect on the survival of female zebrafish (P>0.05). A significant decrease of hepatic vitellogenin (Vtg) was seen in female zebrafish exposed to PS-NPs (P<0.05). The level of 17-β-estradiol (E2) and testosterone (T) were notably declined in female zebrafish of all PS-NPs-exposed groups (P<0.05). Glucose was notably increased in female zebrafish of all PS-NPs-exposed treatments (P<0.05). There was a significant increase in cortisol levels in all PS-NPs-exposed treatments (P<0.05). No significant difference was seen in lactate levels between different treatments (P>0.05). A significant enhancement in aspartate aminotransferase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) was observed in female zebrafish of all PS-NPs-exposed treatments compared to the control (P<0.05). The present results demonstrate that PS-NPs impair the reproduction process so that none of the female zebrafish broodstock exposed to different doses of PS-NPs reached the spawning stage. [ABSTRACT FROM AUTHOR]

Numerous pharmaceutical and industrial chemicals are classified as endocrine‐disrupting chemicals (EDCs) that interfere with hormonal homeostasis, leading to developmental disorders and other pathologies. The synthetic estrogen 17α‐ethynylestradiol (EE2) is used in oral contraceptives and other hormone therapies. EE2 and other estrogens are inadvertently introduced into aquatic environments through municipal wastewater and agricultural effluents. Exposure of male fish to estrogens increases expression of the egg yolk precursor protein vitellogenin (Vtg), which is used as a molecular marker of exposure to estrogenic EDCs. The mechanisms behind Vtg induction are not fully known, and we hypothesized that it is regulated via DNA methylation. Adult zebrafish were exposed to either dimethyl sulfoxide or 20 ng/L EE2 for 14 days. Messenger RNA (mRNA) expression and DNA methylation were assessed in male zebrafish livers at 0, 0.25, 0.5, 1, 4, 7, and 14 days of exposure; and those of females were assessed at 13 days (n ≥ 4/group/time point). To test the persistence of any changes, we included a recovery group that received EE2 for 7 days and did not receive any for the following 7 days, in the total 14‐day study. Methylation of DNA at the vtg1 promoter was assessed with targeted gene bisulfite sequencing in livers of adult male and female zebrafish. A significant increase in vtg1 mRNA was observed in the EE2‐exposed male fish as early as 6 h. Interestingly, DNA methylation changes were observed at 4 days. Decreases in the overall methylation of the vtg1 promoter in exposed males resulted in levels comparable to those in female controls, suggesting feminization. Importantly, DNA methylation levels in males remained significantly impacted after 7 days post–EE2 removal, unlike mRNA levels. These data identify an epigenetic mark of feminization that may serve as an indicator of not only estrogenic exposure but also previous exposure to EE2. Environ Toxicol Chem 2024;43:1547–1556. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

To enhance our understanding of teleost reproductive physiology, we identified six Sichuan bream (Sinibrama taeniatus) vitellogenin genes (vtg1-6) and characterized their sequence structures. We categorized them into type Ⅰ (vtg1,4,5 and 6), type Ⅱ (vtg2) and type Ⅲ (vtg3) based on differences in their subdomain structure. The promoter sequence of vtgs has multiple estrogen response elements, and their abundance appears to correlate with the responsiveness of vtg gene expression to estrogen. Gene expression analyses revealed that the vitellogenesis of Sichuan bream involves both heterosynthesis and autosynthesis pathways, with the dominant pathway originating from the liver. The drug treatment experiments revealed that 17β-estradiol (E2) tightly regulated the level of vtg mRNA in the liver. Feeding fish with a diet containing 100 μg/g E2 for three weeks significantly induced vtg gene expression and ovarian development, leading to an earlier onset of vitellogenesis. Additionally, it was observed that the initiation of vtg transcription required E2 binding to its receptor, a process primarily mediated by estrogen receptor alpha in Sichuan bream. The findings of this study provide novel insights into the molecular information of the vitellogenin gene family in teleosts, thereby contributing to the regulation of gonadal development in farmed fish. [ABSTRACT FROM AUTHOR]

Simple Summary: Varroa destructor is a mite that parasitises honeybee hives, weakening colonies and transmitting viruses. Beekeepers apply acaricide treatments to bee colonies to limit the spread of Varroa and the resulting negative effects on bee health. Oxalic acid treatment is the most widely applied, but little is known about its potential effects on the physiology of bees, particularly their immune system. This study investigated the short-term effects of oxalic acid treatment on the immune and antioxidant systems of house bees (i.e., glucose oxidase, phenoloxidase, glutathione S-transferase, catalase activities, and vitellogenin content). Residual concentrations of oxalic acid on the bees' external body and in the haemolymph were also measured. The results showed that the treatment did not affect the concentration of oxalic acid in the haemolymph, in which it was constitutively present. Residues of oxalic acid remained on the outer body of the bees for up to 48 h after treatment. Both glucose oxidase activity and vitellogenin concentration were affected by the treatment, increasing significantly after 48 and 24 h, respectively. No effects were observed on the other parameters investigated (phenoloxidase, glutathione S-transferase, and catalase activities). Honeybees (Apis mellifera L.) have to face many challenges, including Varroa destructor infestation, associated with viral transmission. Oxalic acid is one of the most common treatments against Varroa. Little is known about the physiological effects of oxalic acid, especially those on honeybees' immune systems. In this study, the short-term effects (0–96 h) of oxalic acid treatment on the immune system components (i.e., glucose oxidase, phenoloxidase, glutathione S-transferase, catalase activities, and vitellogenin contents) of house bees were preliminarily investigated. Oxalic acid contents of bee bodies and haemolymphs were also measured. The results confirm that oxalic acid is constitutively present in bee haemolymphs and its concentration is not affected by treatment. At 6 h after the treatment, a maximum peak of oxalic acid content was detected on bees' bodies, which gradually decreased after that until physiological levels were reached at 48 h. In the immune system, the oxalic acid treatment determined a peak in glucose oxidase activity at 48 h, indicating a potential defence response and an increase in vitellogenin content at 24 h. No significant changes were recorded in phenoloxidase, glutathione S-transferase, and catalase activities. These results suggest a time-dependent response to oxalic acid, with potential immune system activation in treated bees. [ABSTRACT FROM AUTHOR]

Introduction: German cockroach (GCr) aeroallergens are associated with allergic rhinitis and asthma. Vitellogenin (Vg) and vitellin (Vn) are abundant proteins in GCr blood and eggs (including egg cases), respectively, and are possible high molecular mass allergens. Prior efforts to purify Vg/Vn yielded amounts too small for subsequent studies. In this study, we report the affinity purification of Vg/Vn from whole-body defatted GCr powder and determination of the binding of Vg/Vn to anti-GCr IgE. Method: New Zealand white rabbits were immunized with pure Vg/Vn in Freund's adjuvant, and IgG was purified from the rabbit sera and conjugated to cyanogen bromide (CNBr)-activated Sepharose. Aqueous extracts from GCr powder were passed over the column. After extensive washing, putative Vg/Vn was eluted in low-pH buffer, neutralized, and analyzed by SDS-PAGE and liquid chromatography high-resolution mass spectrometry (LC-HRMS). IgE binding of Vg/Vn was evaluated by inhibition of IgE binding to GCr-ImmunoCAP(I6) in sera from 10 GCr-allergic individuals. In addition, Vg/Vn was biotinylated and bound to ImmunoCAP-streptavidin, and direct IgE antibody binding to the immobilized Vg/Vn was determined in sera from 26 GCr-allergic individuals. Results: Vg/Vn isolated by affinity chromatography was 91% pure by LC-HRMS; contaminants included Bla g 3 (0.9%), human keratin (6%), and rabbit IgG. Vg/Vn inhibited IgE binding to GCr-ImmunoCAP(I6) in 8 of 10 sera. In direct-binding experiments, 21/26 (80%) sera had anti-Vg/Vn IgE at>0.10 kUA/L, while 11/26 (42%) sera were>0.35 kUA/L. Conclusions: We affinity-purified Vg/Vn and demonstrated that Vg/Vn-specific IgE antibody is a major component of GCr-specific IgE. [ABSTRACT FROM AUTHOR]

Natural and synthetic environmental estrogens (EEs) are widespread and have received extensive attention. Our previous studies demonstrated that depletion of the cytochrome P450 17a1 gene (cyp17a1) leads to all‐testis differentiation phenotype in zebrafish and common carp. In the present study, cyp17a1‐deficient zebrafish with defective estrogen biosynthesis were used for the evaluation of EEs, as assessed by monitoring vitellogenin (vtg) expression. A rapid and sensitive assessment procedure was established with the 3‐day administration of estradiol (E2), followed by examination of the transcriptional expression of vtgs in our cyp17a1‐deficient fish. Compared with the control fish, a higher E2‐mediated vtg upregulation observed in cyp17a1‐deficient zebrafish exposed to 0.1 μg/L E2 is known to be estrogen receptor–dependent and likely due to impaired in vivo estrogen biosynthesis. The more responsive vtg expression in cyp17a1‐deficient zebrafish was observed when exposed to 200 and 2000 μg/L bisphenol A (BPA) and perfluoro‐1‐octanesulfonate (PFOS). The estrogenic potentials of E2, BPA, and PFOS were compared and assessed by the feminization effect on ovarian differentiation in cyp17a1‐deficient zebrafish from 18 to 50 days postfertilization, based on which a higher sensitivity of E2 in ovarian differentiation than BPA and PFOS was concluded. Collectively, through the higher sensitivity to EEs and the capacity to distinguish chemicals with different estrogenic potentials exhibited by the all‐male cyp17a1‐deficient zebrafish with impaired estrogen biosynthesis, we demonstrated that they can be used as an excellent in vivo model for the evaluation of EEs. Environ Toxicol Chem 2024;43:1062–1074. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Simple Summary: The physiology and performance of individuals in a bee colony are directly related to the quality of nutrients available in the colony. A diet enriched with high-quality protein increases the immunity of the colony and the individual bees. In this study, we examined the effect of diets with different protein sources on dietary consumption, vitellogenin (Vg), abdominal lipid content, and hypopharyngeal gland development in adult worker bees. Our results indicate that the use of certain protein sources in bee diets can improve the parameters investigated. Honey bees play an important role in the pollination of flowering plants. When honey bee colonies are deficient in pollen, one of their main nutrients, protein supplements are required. In this study, the effects of diets with six different protein sources on the physiological characteristics of worker bees (vitellogenin (Vg), abdominal lipid content (ALC), hypopharyngeal gland (HPG)) and consumption were investigated. The protein sources of the diets (diet I, ..., diet VI) included pollen, spirulina dust (Arthrospira platensis Gomont), fresh egg yolk, lyophilized lactose-free skimmed milk powder, active fresh yeast, and ApiProtein. It was identified that consumption by worker bees was highest in the diet group supplemented with spirulina (diet II). Although there was no statistical difference regarding the Vg content in the hemolymph, numerically, the highest content was found in diet group IV (lyophilized lactose-free skimmed milk powder) (4.73 ± 0.03 ng/mL). ALC and HPG were highest in the group fed diet II. These results suggest that offering honey bees diets with certain protein sources can support their physiological traits. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the venom sac extracts (VSEs) of the European hornet (EH) Vespa crabro (Linnaeus, 1758) (Hymenoptera: Vespidae), focusing on the differences between stinging females, gynes (G), and workers (W), at the protein level. Using a quantitative "Sequential Window Acquisition of all Theoretical Fragment Ion Mass Spectra" (SWATH-MS) analysis, we identified and quantified a total of 240 proteins. Notably, within the group, 45.8% (n = 110) showed significant differential expression between VSE-G and VSE-W. In this set, 57.3% (n = 63) were upregulated and 42.7% (n = 47) downregulated in the G. Additionally, the two-hundred quantified proteins from the class Insecta belong to sixteen different species, six of them to the Hymenoptera/Apidae lineage, comprising seven proteins with known potential allergenicity. Thus, phospholipase A1 (Vesp v 1), phospholipase A1 verutoxin 2b (VT-2b), hyaluronidase A (Vesp v 2A), hyaluronidase B (Vesp v 2B), and venom allergen 5 (Vesp v 5) were significantly downregulated in the G, and vitellogenin (Vesp v 6) was upregulated. Overall, 46% of the VSE proteins showed differential expression, with a majority being upregulated in G. Data are available via ProteomeXchange with identifier PXD047955. These findings shed light on the proteomic differences in VSE between EH castes, potentially contributing to our understanding of their behavior and offering insights for allergy research. [ABSTRACT FROM AUTHOR]

Zooplankton undergo a diel vertical migration (DVM) which exposes them to gradients of light, temperature, oxygen, and food availability on a predictable daily schedule. Disentangling the co‐varying and potentially synergistic interactions on metabolic rates has proven difficult, despite the importance of this migration for the delivery of metabolic waste products to the distinctly different daytime (deep) and nighttime (surface) habitats. This study examines the transcriptomic and proteomic profiles of the circumglobal migratory copepod, Pleuromamma xiphias, over the diel cycle. The transcriptome showed that 96% of differentially expressed genes were upregulated during the middle of the day – the period often considered to be of lowest zooplankton activity. The changes in protein abundance were more spread out over time, peaking (42% of comparisons) in the early evening. Between 9:00 and 15:00, both the transcriptome and proteome datasets showed increased expression related to chitin synthesis and degradation. Additionally, at 09:00 and 22:00, there were increases in myosin and vitellogenin proteins, potentially linked to the stress of migration and/or reproductive investment. Based on protein abundances detected, there is an inferred switch in broad metabolic processes, shifting from electron transport system in the day to glycolysis and glycogen mobilization in the afternoon/evening. These observations provide evidence of the diel impact of DVM on transcriptomic and proteomic pathways that likely influence metabolic processes and subsequent excretion products, and clarify how this behaviour results in the direct rapid transport of waste metabolites from the surface to the deep ocean. [ABSTRACT FROM AUTHOR]

Vitellogenin (Vg) is a glycolipid complex protein produced by the fat body of female insects. It plays vital roles in oocyte development and helps regulate reproductive development. In this study, we determined the grading criteria for ovarian development and identified a Vg gene (designated TaVg) from the devastating invasive pest, Tuta absoluta (Meyrick). TaVg contains a 5208 bp open reading frame encoding a protein of 1735 amino acids that includes conserved domain structures of insect Vg. Phylogenetic analysis indicated that TaVg was clustered into a clade with the Vg of other Lepidoptera species, suggesting this gene has been conserved during evolution. Spatiotemporal expression analyses showed that TaVg was highly expressed in the female pupae and adults. There was increased expression during sexual maturation, and the high expression level was found in the ovary and fat body. RNAi-mediated silencing of TaVg resulted in significant downregulation of vitellogenin contents and severely affected ovarian development. Females injected with dsTaVg had shorter ovarian tubes and fewer oocytes compared with the untreated individuals. The number of oocytes and the amount of yolk deposition in the egg chambers also reduced. Depletion of TaVg significantly reduced the number of eggs laid and the hatching rate. Co-silencing of TaVg and TaVgR had a more significant effect on inhibiting the ovarian development and reducing female fecundity of T. absoluta, showing that the two genes play important role in regulating the reproduction. Our results provide potential targets for developing RNAi-based pest management tractic on T. absoluta. [ABSTRACT FROM AUTHOR]

Neoseiulus californicus is a key natural predator of spider mites and small arthropod pests. Although vitellogenin (Vg) and vitellogenin receptor (VgR) genes are important regulators of oocyte maturation, egg formation, and embryonic development in spider mites and ticks, their role in phytoseiid mites is less understood. Investigating the reproductive mechanism of predatory mites is crucial for understanding their reproduction and evolution. In this study, three Vg genes and one VgR gene were identified, cloned, and characterized in N. californicus. Vg1, Vg2, Vg3, and VgR mRNAs were 6066, 5728, 4515, and 5331 bp long, encoding proteins comprising 1851, 1849, 1471, and 1722 amino acids, respectively. Temporal expression analysis revealed elevated Vg1, Vg2, and VgR levels in fertilized female adult mites, whereas Vg3 exhibited peak expression during the developmental stage. RNA interference–mediated suppression of Vg1 and Vg2 resulted in 14.66% and 11.59% decreases in fecundity, respectively. Vg1 silencing notably reduced egg hatching rate and female offspring ratio. In contrast, Vg3 and VgR silencing had no significant impact on fecundity and egg hatching rate. These findings provide insights into the regulatory roles of Vg and VgR in predatory mite reproduction, offering a theoretical foundation for understanding their evolution and reproductive strategies. [ABSTRACT FROM AUTHOR]

Maternal nutritional status can affect development and metabolic phenotypes of progeny in animals. The effects of maternal diet are thought to be mediated mainly by changes inside oocytes such as organelles, maternal RNAs, and metabolites. However, to what extent each factor contributes to offspring phenotypes remains uncertain, especially in viviparous mammalian systems, where factors other than oocytes, such as placenta and milk, need to be considered. Here, using the medaka fish as an oviparous vertebrate model, we examined whether maternal high-fat diet (mHFD) feeding affects offspring development and what kind of changes occur in the contents of mature eggs. We found that mHFD caused the high frequency of embryonic deformities of offspring, accompanied by downregulation of transcription- and translation-related genes and zygotic transcripts at the blastula stage. Transcriptomic and metabolomic analyses of mature eggs suggested decreased catabolism of amino acids and glycogen, moderate upregulation of endoplasmic reticulum stress-related genes, and elevated lipid levels in mHFD eggs. Furthermore, high-fat diet females showed a higher incidence of oocyte atresia and downregulation of egg protein genes in the liver. These data suggest that attenuated amino acid catabolism triggered by decreased yolk protein load/processing, as well as elevated lipid levels inside eggs, are the prime candidates that account for the higher incidence of embryonic deformities in mHFD offspring. Our study presents a comprehensive data on the changes inside eggs in a mHFD model of nonmammalian vertebrates and provides insights into the mechanisms of parental nutritional effects on offspring. [ABSTRACT FROM AUTHOR]

Introduction: Estrogenic chemicals in aquatic environments impact fish reproductive health, with vitellogenin protein levels serving as a crucial biomarker for xenoestrogen exposure. Limited knowledge exists on estrogenic effects in tropical environments, prompting an investigation into the influence of environmental estrogens on Chrysichthys nigrodigitatus in Lagos and Epe lagoons. Methods: A total of 195 fish samples underwent analysis for vitellogenin protein, sex hormones (testosterone and 17 β-estradiol), and gonad pathology in effluentreceiving areas of the specified lagoons. Results: Gonadal alterations were observed in male and female fish, including empty seminiferous tubules and distorted ovaries. Intersex occurred in 3.81% of Lagos and 3.33% of Epe. Testosterone levels were generally higher in females and males from both lagoons, while E2 levels were higher in females from both lagoons, with Lagos showing higher levels than Epe. Vtg levels were higher in males than females in Lagos samples but showed no significant difference in Epe samples. Discussion: Contaminant analysis revealed similar trends in metals (Hg, As, Cr) and phthalates (DEHP, DBP, DEP) in both sexes in the Epe population. Multivariate depictions from the PCA showed sex-specific patterns of metal uptake (Cd) in male fishes at the Lagos Lagoon. The positive association between higher pH loadings and metal and DBP levels in sediment at the Lagos lagoon suggests the influence of higher alkalinity in lower bioavailability of contaminants. Conclusion: Endocrine disrupting effects were observed in male and female Chrysichthys nigrodigitatus in Lagos and Epe lagoons populations, with notable differences in hormone and contaminant concentrations between the two lagoon systems. Identification of specific contaminants and their spatial and temporal trends can inform targeted management and remediation efforts to protect and restore these valuable aquatic ecosystems. [ABSTRACT FROM AUTHOR]

In insects, vitellogenin (Vg) is generally viewed as a female‐specific protein. Its primary function is to supply nutrition to developing embryos. Here, we reported Vg from the male adults of a natural predator, Chrysopa pallens. The male Vg was depleted by RNAi. Mating with Vg‐deficient male downregulated female Vg expression, suppressed ovarian development and decreased reproductive output. Whole‐organism transcriptome analysis after male Vg knockdown showed no differential expression of the known spermatogenesis‐related regulators and seminal fluid protein genes, but a sharp downregulation of an unknown gene, which encodes a testis‐enriched big protein (Vcsoo). Separate knockdown of male Vg and Vcsoo disturbed the assembly of spermatid cytoplasmic organelles in males and suppressed the expansion of ovary germarium in mated females. These results demonstrated that C. pallens male Vg signals through the downstream Vcsoo and regulates male and female reproduction. [ABSTRACT FROM AUTHOR]

Vitellogenin (Vtg) is a precursor of yolk proteins in egg-laying vertebrates and invertebrates and plays an important role in vitellogenesis and embryonic development. However, the Vtg family remains poorly characterized in Exopalaemon carinicauda, a major commercial mariculture species found along the coasts of the Yellow and Bohai Seas. In this study, 10 Vtg genes from the genomes of E. carinicauda were identified and characterized. Phylogenetic analyses showed that the Vtg genes in crustaceans could be classified into four groups: Astacidea, Brachyra, Penaeidae, and Palaemonidae. EcVtg genes were unevenly distributed on the chromosomes of E. carinicauda, and a molecular evolutionary analysis showed that the EcVtg genes were primarily constrained by purifying selection during evolution. All putative EcVtg proteins were characterized by the presence of three conserved functional domains: a lipoprotein N-terminal domain (LPD_N), a domain of unknown function (DUF1943), and a von Willebrand factor type D domain (vWD). All EcVtg genes exhibited higher expression in the female hepatopancreas than in other tissues, and EcVtg gene expression during ovarian development suggested that the hepatopancreas is the main synthesis site in E. carinicauda. EcVtg1a, EcVtg2, and EcVtg3 play major roles in exogenous vitellogenesis, and EcVtg3 also plays a major role in endogenous vitellogenesis. Bilateral ablation of the eyestalk significantly upregulates EcVtg mRNA expression in the female hepatopancreas, indicating that the X-organ/sinus gland complex plays an important role in ovarian development, mostly by inducing Vtg synthesis. These results could improve our understanding of the function of multiple Vtg genes in crustaceans and aid future studies on the function of EcVtg genes during ovarian development in E. carinicauda. [ABSTRACT FROM AUTHOR]

The red imported fire ant (Solenopsis invicta Buren) is a social pest species with a robust reproductive ability that causes extensive damage. Identification of the genes involved in queen fertility is critical in order to better understand the reproductive biology and screening for the potential molecular targets in S. invicta. Here, we used the mRNA deep sequencing (RNA-seq) approach to identify differentially expressed genes (DEGs) in the transcriptomes of three reproductive caste types of S. invicta, including queen (QA) and winged female (FA) and male (MA) ants. The genes that were specific to and highly expressed in the queens were then screened, and the Vg2 and Vg3 genes were chosen as targets to explore their functions in oogenesis and fertility. A minimum of 6.08 giga bases (Gb) of clean reads was obtained from all samples, with a mapping rate > 89.78%. There were 7524, 7133, and 977 DEGs identified in the MA vs. QA, MA vs. FA, and FA vs. QA comparisons, respectively. qRT–PCR was used to validate 10 randomly selected DEGs, including vitellogenin 2 (Vg2) and 3 (Vg3), and their expression patterns were mostly consistent with the RNA-seq data. The S. invicta Vgs included conserved domains and motifs that are commonly found in most insect Vgs. SiVg2 and SiVg3 were highly expressed in queens and winged females and were most highly expressed in the thorax, followed by the fat body, head, and epidermis. Evaluation based on a loss-of-function-based knockdown analysis showed that the downregulation of either or both of these genes resulted in smaller ovaries, less oogenesis, and less egg production. The results of transcriptional sequencing provide a foundation for clarifying the regulators of queen fertility in S. invicta. The functions of SiVg2 and SiVg3 as regulators of oogenesis highlight their importance in queen fecundity and their potential as targets of reproductive disruption in S. invicta control. [ABSTRACT FROM AUTHOR]

Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming industry. Nosema bombycis is a typical microsporidium that infects multiple lepidopteran insects via fecal-oral and transovarial transmission (TOT); however, the underlying TOT processes and mechanisms remain unknown. Here, we characterized the TOT process and identified key factors enabling N. bombycis to invade the ovariole and oocyte of silkworm Bombyx mori. We found that the parasites commenced with TOT at the early pupal stage when ovarioles penetrated the ovary wall and were exposed to the hemolymph. Subsequently, the parasites in hemolymph and hemolymph cells firstly infiltrated the ovariole sheath, from where they invaded the oocyte via two routes: (I) infecting follicular cells, thereby penetrating oocytes after proliferation, and (II) infecting nurse cells, thus entering oocytes following replication. In follicle and nurse cells, the parasites restructured and built large vacuoles to deliver themselves into the oocyte. In the whole process, the parasites were coated with B. mori vitellogenin (BmVg) on their surfaces. To investigate the BmVg effects on TOT, we suppressed its expression and found a dramatic decrease of pathogen load in both ovarioles and eggs, suggesting that BmVg plays a crucial role in the TOT. Thereby, we identified the BmVg domains and parasite spore wall proteins (SWPs) mediating the interaction, and demonstrated that the von Willebrand domain (VWD) interacted with SWP12, SWP26 and SWP30, and the unknown function domain (DUF1943) bound with the SWP30. When disrupting these interactions, we found significant reductions of the pathogen load in both ovarioles and eggs, suggesting that the interplays between BmVg and SWPs were vital for the TOT. In conclusion, our study has elucidated key aspects about the microsporidian TOT and revealed the key factors for understanding the molecular mechanisms underlying this transmission. Author summary: In addition to horizontal transmission, certain species of microsporidia possess the capability of vertically transmitting to host offspring by invading parental oocytes, a process known as transovarial transmission (TOT). However, the pathways and mechanisms through which these parasites penetrate the host barrier system and enter oocytes remain unclear. This study elucidates a comprehensive process in which the microsporidian Nosema bombycis infects various components of the silkworm Bombyx mori ovariole sheath, including follicular cells (FCs) and nurse cells (NCs), ultimately reaching their destination within the oocytes. Within FCs and NCs, N. bombycis undergoes restructuring and forms large vacuoles for delivering themselves into the oocyte. Furthermore, we have identified B. mori vitellogenin (BmVg) and specific spore wall proteins (SWP12, SWP26, SWP30) from N. bombycis as key factors involved in TOT. Additionally, our findings showed that specific domains within BmVg (VWD and DUF1943) are essential for binding with these spore wall proteins. Overall, this study represents pioneering work that illustrates both the process by which N. bombycis infects host oocytes and identifies crucial molecules that play vital roles in TOT mechanism. These findings provide novel perspectives on understanding pathogen-host interactions while advancing our knowledge of TOT mechanisms employed by pathogens. [ABSTRACT FROM AUTHOR]

Insect vitellogenins are an intriguing class of complex proteins. They primarily serve as a source of energy for the developing embryo in insect eggs. Vitellogenesis is a complex hormonally and neurally controlled process that command synthesis of vitellogenin molecules and ensures their transport from the female fat bodies or ovarial cells into eggs. The representatives of all insect hormones such as juvenile hormones, ecdysteroids, and neurohormones participate in vitellogenesis, but juvenile hormones (most insect species) and ecdysteroids (mostly Diptera) play the most important roles in the process. Strikingly, not only insect females, but also males have been reported to synthesize vitellogenins indicating their further utility in the insect body. Indeed, it has recently been found that vitellogenins perform a variety of biological functions in the insect body. They participate in defense reactions against entomopathogens such as nematodes, fungi, and bacteria, as well as against venoms such as the honeybee Apis mellifera venom. Interestingly, vitellogenins are also present in the venom of the honeybee itself, albeit their exact role is unknown; they most likely increase the efficacy of the venom in the victim's body. Within the bee's body vitellogenins contribute to the lifespan regulation as antiaging factor acting under tight social interactions and hormonal control. The current minireview covers all of these functions of vitellogenins and portrays them as biologically active substances that play a variety of significant roles in both insect females and males, and not only acting as passive energy sources for developing embryo. [ABSTRACT FROM AUTHOR]

The specific functions and essentiality of type II vitellogenin (Vtg2) in early zebrafish development were investigated in this study. A vtg2-mutant zebrafish line was produced and effects of genomic disturbance were observed in F2 females and F3 offspring. No change in vtg2 transcript has been detected, however, Vtg2 abundance in F2 female liver was 5×, and in 1 hpf F3 vtg2-mutant embryos was 3.8× less than Wt (p < 0.05). Fecundity was unaffected while fertilization rate was more than halved in F2 vtg2-mutant females (p < 0.05). Hatching rate was significantly higher in F3 vtg2-mutant embryos in comparison to Wt embryos. Survival rate declined drastically to 29% and 18% at 24 hpf and 20 dpf, respectively, in F3 vtg2-mutant embryos. The introduced mutation caused vitelline membrane deficiencies, significant mortalities at early embryonic stages, and morphological abnormalities in the surviving F3 vtg2-mutant larvae. Overrepresentation of histones, zona pellucida proteins, lectins, and protein degradation related proteins in F3 vtg2-mutant embryos provide evidence to impaired mechanisms involved in vitellin membrane formation. Overall findings imply a potential function of Vtg2 in acquisition of vitellin membrane integrity, among other reproductive functions, and therefore, its essentiality in early zebrafish embryo development. [ABSTRACT FROM AUTHOR]

Simple Summary: Bees are often fed by beekeepers with supplemented artificial diets. The formulation of an integrative diet for honey bee colonies able to prevent nutritional deficiencies is yet to be found. In this work, the effects of fat-enriched diet (coconut oil) administration in newly emerged and forager bees were tested. Fat supplementation in the honey bee diet determines an increase in newly emerged bees' survival in the short term and an increase in fat content. Further investigations to evaluate the use of such a supplement food to prevent the fat loss of weak families during winter are desirable. Searching for artificial diets positively affecting the survival, immune and antioxidant systems of honey bees is one of main challenges occurring in beekeeping. Among nutrients, lipids play a significant role in insect nutrition as structural components in cell membranes, energy sources and reserves, and are involved in many physiological processes. In this context, the aim of this work was to investigate the effect of 0.5% and 1% coconut oil-enriched diet administration on newly emerged and forager bees survival rate, feed intake, immune system, antioxidant system and both fat and vitellogenin content. In newly emerged bees, supplementation with 1% coconut oil determined a decrease in feed consumption, an increase in survival rate from the 3rd to 14th day of feeding, a short-term decrease in phenoloxidase activity, an increase in body fat and no differences in vitellogenin content. Conversely, supplementation with 0.5% coconut oil determined an increase in survival rate from the 3rd to 15th day of feeding and an increase in fat content in the long term (i.e., 20 days). Regarding the forager bee diet, enrichment with 0.5% and 1% coconut oil only determined an increase in fat content. Therefore, supplementation with coconut oil in honey bee diets at low percentages (0.5 and 1%) determines fat gain. Further investigations to evaluate the use of such supplement foods to prevent the fat loss of weak families during winter are desirable. [ABSTRACT FROM AUTHOR]

Insects often face both conditions with sufficient nutrients and conditions of undernutrition in the field. Through gustatory receptors, insects sense nutrients and regulate their physiological functions such as feeding and reproduction. However, it remains unclear whether signaling pathways activated by gustatory receptors depend on the concentration of nutrients and whether the difference in signaling pathways directly affects insects' physiological functions. Herein, we found that a sugar gustatory receptor, NlGr11, from the brown planthopper (BPH), Nilaparvata lugens, activated G protein‐coupled signaling and ionotropic pathways when bound to high galactose concentration. BPHs subsequently demonstrated longer feeding times, feeding loads, and higher vitellogenin (NlVg) expression than BPHs exposed to high galactose concentrations, which only activated the ionotropic pathway. For the first time, our findings link plant nutrient conditions, signaling pathways activated by nutrients, and their gustatory receptors, and nutrient dose‐dependent feeding efficacy and vitellogenin (Vg) expression in an insect. This will help us to better understand the molecular mechanism for insect feeding strategies on plants at different stages of nutritional conditions. [ABSTRACT FROM AUTHOR]

As an oocyte-specific growth factor, bone morphogenetic protein 15 (BMP15) plays a critical role in controlling folliculogenesis. However, the mechanism of BMP15 action remains elusive. Using zebrafish as the model, we created a bmp15 mutant using CRISPR/Cas9 and demonstrated that bmp15 deficiency caused a significant delay in follicle activation and puberty onset followed by a complete arrest of follicle development at previtellogenic (PV) stage without yolk accumulation. The mutant females eventually underwent female-to-male sex reversal to become functional males, which was accompanied by a series of changes in secondary sexual characteristics. Interestingly, the blockade of folliculogenesis and sex reversal in bmp15 mutant could be partially rescued by the loss of inhibin (inha-/-). The follicles of double mutant (bmp15-/-;inha-/-) could progress to mid-vitellogenic (MV) stage with yolk accumulation and the fish maintained their femaleness without sex reversal. Transcriptome analysis revealed up-regulation of pathways related to TGF-β signaling and endocytosis in the double mutant follicles. Interestingly, the expression of inhibin/activin βAa subunit (inhbaa) increased significantly in the double mutant ovary. Further knockout of inhbaa in the triple mutant (bmp15-/-;inha-/-;inhbaa-/-) resulted in the loss of yolk granules again. The serum levels of estradiol (E2) and vitellogenin (Vtg) both decreased significantly in bmp15 single mutant females (bmp15-/-), returned to normal in the double mutant (bmp15-/-;inha-/-), but reduced again significantly in the triple mutant (bmp15-/-;inha-/-;inhbaa-/-). E2 treatment could rescue the arrested follicles in bmp15-/-, and fadrozole (a nonsteroidal aromatase inhibitor) treatment blocked yolk accumulation in bmp15-/-;inha-/- fish. The loss of inhbaa also caused a reduction of Vtg receptor-like molecules (e.g., lrplab and lrp2a). In summary, the present study provided comprehensive genetic evidence that Bmp15 acts together with the activin-inhibin system in the follicle to control E2 production from the follicle, Vtg biosynthesis in the liver and its uptake by the developing oocytes. Author summary: Bone morphogenetic protein 15 (BMP15) is an oocyte-secreted growth factor that plays an essential role in female reproduction. However, scientists still do not fully understand how it works. In this study, we used zebrafish as the model to study the role of BMP15 in egg development. We genetically modified the zebrafish to delete the gene of BMP15 (bmp15). Without BMP15, the eggs failed to grow normally, and the female fish eventually changed sex to become males. However, if another protein, inhibin (inha), was also removed, the fish stayed females and their eggs could develop more normally. We found that removing inhibin changed expression of many other genes, including aromatase (cyp19a1a), the enzyme that makes female sex steroids (estrogens). We further demonstrated that the loss of aromatase was indeed the main reason for the failure of egg development in the fish without BMP15, and that removing inhibin helped restore the production of estrogens. In conclusion, this study found that BMP15 is vital for egg development and maintaining the female sex in fish and that it works by controlling production of female sex steroids. [ABSTRACT FROM AUTHOR]

Recent research on decapod crustaceans revealed the presence of multiple vitellogenin genes within a single species. Characterizing their expression dynamics and regulatory mechanisms is helpful for the sustainability of commercially relevant decapods through a greater comprehension of vitellogenesis. However, it is unclear whether multiple vitellogenin genes exist in the kuruma prawn Marsupenaeus japonicus, an essential species in several Asian countries. This study determined the full-length cDNA sequence of the new vitellogenin (Maj-Vg2) using transcriptome analysis and cDNA cloning. The deduced Maj-Vg2 consisted of 2,554 amino acids and shared only 53.8% identity with Maj-Vg1, the known vitellogenin of this species. The Maj-Vg1 gene (Maj-Vg1) was expressed in both the hepatopancreas and ovary, whereas the Maj-Vg2 gene (Maj-Vg2) was expressed only in the hepatopancreas. Maj-Vg2 expression in the hepatopancreas was low during the previtellogenic stage and increased during the early and late yolk globule stages. When eyestalks were ablated from immature prawns, Maj-Vg2 expression in the hepatopancreas increased significantly, like Maj-Vg1 expression in the ovary, suggesting possible regulation by hormones from the eyestalk ganglia. These results suggested that Maj-Vg2 and Maj-Vg1 are involved in vitellogenesis in this species. [ABSTRACT FROM AUTHOR]

Endocrine disruptors in marine environments represented by estrogens lead to reverse health phenomena. To obtain a more effective way to reflect and detect environmental estrogens pollution, a method was developed to obtain the full-length cDNA coding vitellogenin gene in B. sinensis, induced by 17β-estradiol (E2) solution. We have downloaded 16 fish gene sequences from the NCBI database and designed PCR primers accordingly. Based on the quantitative real-time PCR method (qRT-PCR), we analyze the differences in gene expression under the conditions of different E2 exposure times in the low, middle, and high-dose groups. The full-length cDNA consists of 4738 nucleotides with a reading frame encoding 1540 amino acid residues. In vitro recombinant plasmids were constructed and transferred to E. coli BL21 for vitellogenin expression. Efficient fusion expression was obtained by IPTG at 16°C, and the expressed target protein (680 amino acids, 75 kDa) existed in a soluble state, accounting for more than 25% of the total soluble protein. We prepared monoclonal antibodies using established immunohistochemistry to detect vitellogenin expression sites in sexually mature female fish. Our study shows that the expression sites of Vg in sexually mature female fish are mainly distributed in the fishtail, hepatopancreas, intestine, muscle, ovary, and pronephric kidney. In conclusion, the vitellogenin from B. sinensis could be used as a biomarker of environmental estrogens to achieve rapid detection in the marine environment and the subsequent experiments of development in colloidal gold strips after this research would be established to provide a highly efficient and convenient detection method for environment pollution. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr (VI)) is widely distributed in the marine environment of Hainan Province, China and poses a potential threat to its mangrove ecosystems. However, the mechanisms underlying Cr-induced stress and reproductive toxicity in clams remain largely unknown. In this study, the clams, Geloina erosa, were exposed to 4.34, 8.69, 17.38 and 34.76 mg/L Cr (VI) for 24, 48 and 72 h. The gonad-somatic index (GSI) was determined and histological alterations of the ovaries were quantified by light microscopy. The micronucleus test was performed which quantifies the genotoxic presence of small cytoplasmic bodies in eukaryotic cells. Enzymatic assays for catalase (CAT), glutathione reductase (GR), and malondialdehyde (MDA) activities were done. Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of glutathione-S-transferase (GST), heat shock protein 70 (HSP70) and vitellogenin (Vtg) in ovaries of G. erosa. The results showed that the micronucleus frequency was significantly increased when clams were exposed to Cr (VI). Cr (VI) exposure induced the accumulation of MDA and affected CAT and GR enzyme activities. The high Cr (VI) concentration of 34.76 mg/L significantly increased the levels of GR activity, GST expression and HSP70 expression and inhibited Vtg expression and CAT activity. MDA content was significantly increased after 72 h at the high Cr (VI) exposure (34.76 mg/L). Therefore, Cr (VI) exposure may be toxic to the development of ovaries of G. erosa. [ABSTRACT FROM AUTHOR]

Vitellogenesis is the main event of oocyte growth in oviparous animals, which is mainly manifested by the accumulation of vitellogenin (VTG). The accumulation of vitellogenin depends mainly on the absorption of exogenous vitellogenin, which enters oocyte through endocytosis mediated by its receptor (VGR). We investigated the expression and localization of VTG and VGR during gonad development of Pampus argenteus. The qPCR results show that vtgs were not expressed in male fish, but in the ovary and liver of female fish; the expression levels went up at first and then down. The expression levels of vgr in the testis were low and only 1%–3% of that in ovary. ELISA results show that during the ovarian development of P. argenteus, VTG in liver, serum, and ovary all showed a trend from increasing to decreasing. However, VTG in liver peaked in Stage IV, and in serum and ovary peaked in Stage V, reflecting changes in the characteristics of VTG in the liver (synthesis), blood (transport), and ovaries (accumulation). During gonad development, VGR in the ovaries first increased and then decreased, reaching a peak in Stage V, in contrast to vgr mRNA expression. The VGR content in the testis was extremely low and stable, consistent with vgr mRNA. Immunohistochemistry results show that the location and intensity of VTG and VGR positive signals were synchronized with the changes of their protein content, which revealed that VTG was mainly synthesized in the liver cytoplasm, secreted into the blood, and transported to ovary in Stage III. VGR is highly expressed in oocytes in Stage II. In Stage III, a large amount of VTG reaches the ovary, when VGR begins to translate and is subsequently transported to the plasma membrane of the oocyte. Therefore, the positive signal of VGR was stronger near the plasma membrane of oocytes in Stages I and II. By using qPCR, ELISA, and immunohistochemistry, the synthesis, transport, and accumulation of vitellogenin were elucidated and the mechanism of its endocytosis on egg membrane mediated by VTG during the development of P. argenteus was revealed preliminarily. [ABSTRACT FROM AUTHOR]

To explore the effects of salinity on the growth and gonadal development of Exopalaemon carinicauda, shrimps were raised at five different levels of salinity (16, 20, 24, 28, 32) in a water environment. The growth, performance in ovarian development, ovarian nutrient concentration, as well as vitellogenin and sex hormone levels were measured. The results showed that the final body weight and specific growth rate of E. carinicauda increased at first and then decreased with increasing salinity (P <0.05), with the fastest growth occurring at salinity 24. The gonadosomatic index increased at first and then decreased with increasing salinity (P <0.05), with the highest index also occurring at salinity 24. The ovarian maturation rate of E. carinicauda was highest at salinity 28, and the concentration of total protein, total cholesterol, and triglycerides in the ovaries similarly increased at first until salinity 24, and then decreased with increasing salinity (P <0.05). Likewise, the concentration of vitellogenin in the hepatopancreas increased at first and then decreased with increasing salinity (P <0.05), with the highest concentration occurring at salinity 24. The concentration of estradiol in E. carinicauda ovaries was highest in the groups at salinities 24 and 28. These results show that salinity levels of 24-28 were the most suitable for promoting the maturation of parent shrimps, and thus would likely be optimal for industrial culturing. [ABSTRACT FROM AUTHOR]

Diaphorina citri, a vector of citrus huanglongbing (HLB) disease, frequently leads to HLB outbreaks and reduces Rutaceae crop production. Recent studies have investigated the effects of RNA interference (RNAi) targeting the Vitellogenin (Vg4) and Vitellogenin receptor (VgR) genes, which are involved in egg formation in this pest, providing a theoretical foundation for developing new strategies to manage D. citri populations. This study presents RNAi methods for Vg4 and VgR gene expression interference and reveals that dsVgR is more effective than dsVg4 against D. citri. We demonstrated that dsVg4 and dsVgR persisted for 3–6 days in Murraya odorifera shoots when delivered via the in-plant system (IPS) and effectively interfered with Vg4 and VgR gene expression. Following Vg4 and VgR gene expression interference, egg length and width in the interference group were significantly smaller than those in the negative control group during the 10–30-day development stages. Additionally, the proportion of mature ovarian eggs in the interference group was significantly lower than that in the negative control group at the 10, 15, 20, 25, and 30-day developmental stages. DsVgR notably suppresses oviposition in D. citri, with fecundity decreasing by 60–70%. These results provide a theoretical basis for controlling D. citri using RNAi to mitigate the spread of HLB disease. [ABSTRACT FROM AUTHOR]

Vitellogenin (VTG), an egg yolk precursor, is abnormally produced by male and juvenile oviparous species after exposure to estrogens. Plasma VTG in loggerhead sea turtles (Caretta caretta) helped us understand their reproductive maturation and investigate it as a biomarker of contaminant exposure. The presence of VTG was screened in plasma from 404 loggerheads from the northwestern Atlantic Ocean using a freshwater turtle antibody in western blots. The concentrations of VTG were semiquantified using band intensities calibrated to results from a loggerhead antibody enzyme‐linked immunoassay. The detection and concentrations of VTG were in (from highest to lowest): nesting females, in‐water adult females, subadult females, smaller females, unknown sex, and males. Loggerheads from this region begin vitellogenesis at ≅77 cm straight carapace length. We classified VTG expression as abnormal in nine male or juvenile turtles. Organochlorine contaminant (OC) concentrations were measured in blood and/or fat biopsies of some turtles. One abnormal VTG female had the second highest fat polychlorinated biphenyl (PCB) and 4,4′‐dichlorodiphenyldichloroethylene concentrations compared among 43 VTG‐negative juveniles. The nine VTG‐abnormal turtles had average blood PCB concentrations 8.5% higher, but not significantly different, than 46 VTG‐negative juveniles (p = 0.453). In turtles less than 77 cm, blood PCB concentrations were significantly, but weakly, correlated with semiquantified VTG concentrations (tau = 0.1, p = 0.004). Greater blood OC concentrations were found in adult females than in males, which motivated the creation of a conceptual model of OC, VTG, and hormone concentrations across a reproductive cycle. A decision tree is also provided incorporating VTG as a sexing tool. Abnormal VTG expression cannot conclusively be linked to endocrine disruption caused by these OC concentrations. Studies should further investigate causes of abnormal VTG expression in wild sea turtles. Environ Toxicol Chem 2023;42:1309–1325. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

Dermanyssus gallinae is a blood-feeding mite that parasitises wild birds and farmed poultry. Its remarkably swift processing of blood, together with the capacity to blood-feed during most developmental stages, makes this mite a highly debilitating pest. To identify specific adaptations to digestion of a haemoglobin-rich diet, we constructed and compared transcriptomes from starved and blood-fed stages of the parasite and identified midgut-enriched transcripts. We noted that midgut transcripts encoding cysteine proteases were upregulated with a blood meal. Mapping the full proteolytic apparatus, we noted a reduction in the suite of cysteine proteases, missing homologues for Cathepsin B and C. We have further identified and phylogenetically analysed three distinct transcripts encoding vitellogenins that facilitate the reproductive capacity of the mites. We also fully mapped transcripts for haem biosynthesis and the ferritin-based system of iron storage and inter-tissue trafficking. Additionally, we identified transcripts encoding proteins implicated in immune signalling (Toll and IMD pathways) and activity (defensins and thioester-containing proteins), RNAi, and ion channelling (with targets for commercial acaricides such as Fluralaner, Fipronil, and Ivermectin). Viral sequences were filtered from the Illumina reads and we described, in part, the RNA-virome of D. gallinae with identification of a novel virus, Red mite quaranjavirus 1. Genes associated with the consumption of blood and iron storage are identified in the poultry red mite, along with presentation of a partial virome. [ABSTRACT FROM AUTHOR]

Summary: Vitellogenins (Vgs) are critical for the development and fecundity of insects. As such, these essential proteins can be used by plants to reliably sense the presence of insects.We addressed this with a combination of molecular and chemical analyses, genetic transformation, bioactivity tests, and insect performance assays.The small N‐terminal subunit of Vgs of the planthopper Nilaparvata lugens (NlVgN) was found to trigger strong defense responses in rice when it enters the plants during feeding or oviposition by the insect. The defenses induced by NlVgN not only decreased the hatching rate of N. lugens eggs, but also induced volatile emissions in plants, which rendered them attractive to a common egg parasitoid. VgN of other planthoppers triggered the same defenses in rice. We further show that VgN deposited during planthopper feeding compared with during oviposition induces a somewhat different response, probably to target the appropriate developmental stage of the insect.We also confirm that NlVgN is essential for planthopper growth, development, and fecundity. This study demonstrates that VgN in planthopper eggs and saliva acts as a reliable and unavoidable elicitor of plant defenses. Its importance for insect performance precludes evolutionary adaptions to prevent detection by rice plants. [ABSTRACT FROM AUTHOR]

Polycyclic musk compounds are commonly used in personal care products to replace expensive natural fragrances. Due to their huge consumption, they have become a part of the aquatic environment. In the present study, a two-month exposure effect of tonalide on juvenile zebrafish (Danio rerio) was investigated. We determined the vitellogenin concentration to define the potential endocrine-disrupting effect of tonalide and also analysed selected indices to evaluate the induction of oxidative stress. The environmentally relevant concentration of tonalide (i.e., 500 ng/l) caused a significant decrease in the catalase activity (P < 0.05) and a significant increase (P < 0.05) in the lipid peroxidation. An increasing lipid peroxidation was also recorded for the highest concentration group tested (i.e., 50 000 ng/l). On the other hand, no significant changes were recorded in vitellogenin in all the exposed groups. Thus, based on these results, we have not demonstrated the endocrine-disrupting activity of tonalide in zebrafish. The results of the oxidative stress indices showed a significant impairment of the antioxidant defence after the two-month tonalide exposure, which could indicate part of the adaptive response to the tonalide toxicity. [ABSTRACT FROM AUTHOR]

Thrips hawaiiensis (Morgan) (Thysanoptera: Thripidae) is a sap-sucking pest that seriously damages several crops and reduces their economic value. Exposure to low concentrations of insecticides may have a sublethal effect on surviving insects. In order to provide a reference for the rational application of emamectin benzoate, its sublethal effects on the development and reproduction of T. hawaiiensis were evaluated. Pupal development time was significantly shorter in T. hawaiiensis treated with sublethal concentrations of emamectin benzoate (LC10 and LC20) than in control. Female adult longevity and female total longevity were significantly longer following LC20 treatment than in the control and LC10 treatment groups. Nevertheless, male adult longevity and male total longevity were significantly shorter in the LC10 treatment group than in the control and LC20 treatment groups. The sublethal concentration of emamectin benzoate (LC20) significantly shortened the preadult stages and the mean generation. Meanwhile, it significantly increased the finite rate of increase, intrinsic rate of increase, and net reproductive rate. The fecundity was significantly higher after LC20 treatment than after LC10 and control treatments. Compared with the control group, the LC10 and LC20 groups of T. hawaiiensis adults showed a significantly higher expression of the vitellogenin (Vg) and vitellogenin receptor (VgR) genes, which played a key role in increasing their fecundity. These findings suggest that short-term exposure to sublethal concentrations of emamectin benzoate may lead to a resurgence and secondary outbreak of T. hawaiiensis infestation. The results have practical applications for the management of this important and noxious pest. [ABSTRACT FROM AUTHOR]

Summary: Plant-parasitic nematodes (PPN) are an economically important group of crop pests and are oviparous animals; all nutrients required to develop and ensure the survival of their unhatched progeny need to be deposited within the egg, including proteins. The most abundant protein deposited is vitellin, formed of a precursor protein vitellogenin, which has roles in transporting lipids, providing amino acids and influencing post-embryonic development. The genes encoding vitellogenin have been well studied in Caenorhabditis elegans , but little is known about vitellogenin in PPN. Using the vitellogenin gene sequences from C. elegans , homologous sequences in the genomes of some economically important cyst and root-knot nematodes were identified and hypothetical vitellogenin genes were predicted. Protein domains were then determined. Sequences were aligned using MUSCLE and then used to construct phylogenetic trees using the maximum likelihood method. With the availability of genomic data and use of online local alignment tools, the vitellogenin encoding genes from C. elegans could be aligned to PPN genomes. All predicted genes contained the same protein domains as C. elegans ; Vitellogenin_N, vitellogenin open beta-sheet and von Willebrand factor domain type D. The constructed phylogenetic tree clustered the species into four groups: root-knot nematodes, two cyst nematode groups and Caenorhabditis species. By determining the hypothetical vitellogenin genes in PPN and inferring their relationships, this could form a potential basis to understand further the role of vitellogenin in cyst and root-knot nematodes. [ABSTRACT FROM AUTHOR]

Vitellogenesis is the process in which female oviparous vertebrates synthesize the protein vitellogenin to develop egg yolk. In some species, vitellogenin has been used to investigate reproductive status, as a biomarker of clutch size and nesting frequency, and as a biomarker of exposure to endocrine-disruptive chemicals. The Diamond-backed Terrapin (Malaclemys terrapin) is an obligate coastal species that in the northern extent of its range nests in the spring and summer months. Diamond-backed Terrapins serve as a key indicator species of coastal ecosystem health; thus, furthering our understanding of the endocrine control of reproduction may inform biologists of the health and status of coastal ecosystems. The objective of this study was to quantify baseline values of vitellogenin and testosterone in Diamond-backed Terrapins during the nesting season, in the northern part of their range. Blood samples were taken from adult female terrapins from two populations in coastal New Jersey from June-August. Enzyme-linked immunosorbent assays (ELISAs) were used to quantify vitellogenin (VTG) and testosterone (T) across the nesting season. VTG concentrations showed peak values in the earliest part of the nesting season, significantly declining through the summer before reaching basal values in August, with T showing a similar trend. This suggests that terrapins in New Jersey follow a similar reproductive cycle to other turtle species from temperate latitudes. Additionally, we found that larger females exhibited higher concentration of T and VTG than smaller females. This suggests that VTG and T are useful biomarkers of reproductive output in these animals. Lastly, we also noted that larger females tended to nest earlier in the nesting season than smaller females. We hypothesize that larger females may compete for resources more effectively and efficiently than smaller females, which may confer larger individuals a fitness advantage. [ABSTRACT FROM AUTHOR]

Reproductive modes of vertebrates are classified into two major embryonic nutritional types: yolk deposits (i.e. lecithotrophy) and maternal investment (i.e. matrotrophy). Vitellogenin (VTG), a major egg yolk protein synthesized in the female liver, is one of the molecules relevant to the lecithotrophy-to-matrotrophy shift in bony vertebrates. In mammals, all VTG genes are lost following the lecithotrophy-to-matrotrophy shift, and it remains to be elucidated whether the lecithotrophy-to-matrotrophy shift in nonmammalians is also associated with VTG repertoire modification. In this study, we focused on chondrichthyans (cartilaginous fishes)—a vertebrate clade that underwent multiple lecithotrophy-to-matrotrophy shifts. For an exhaustive search of homologs, we performed tissue-by-tissue transcriptome sequencing for two viviparous chondrichthyans, the frilled shark Chlamydoselachus anguineus and the spotless smooth-hound Mustelus griseus , and inferred the molecular phylogeny of VTG and its receptor very low-density lipoprotein receptor (VLDLR), across diverse vertebrates. As a result, we identified either three or four VTG orthologs in chondrichthyans including viviparous species. We also showed that chondrichthyans had two additional VLDLR orthologs previously unrecognized in their unique lineage (designated as VLDLRc2 and VLDLRc3). Notably, VTG gene expression patterns differed in the species studied depending on their reproductive mode; VTGs are broadly expressed in multiple tissues, including the uterus, in the two viviparous sharks, and in addition to the liver. This finding suggests that the chondrichthyans VTGs do not only function as the yolk nutrient but also as the matrotrophic factor. Altogether, our study indicates that the lecithotrophy-to-matrotrophy shift in chondrichthyans was achieved through a distinct evolutionary process from mammals. [ABSTRACT FROM AUTHOR]

In order to examine the role of the central nervous system in regulating ovarian maturation in the whiteleg shrimp, Litopenaeus vannamei, we incubated ovarian explants taken from adult shrimp with either brain or thoracic ganglion extracts at the level of five tissue equivalents for 6 h. For assessment of the effects of each tissue extract, transcriptional expression of vitellogenin mRNA in incubated ovarian tissue fragments was analyzed by quantitative real-time PCR. Results showed that crude brain extracts and a 90% aqueous acetonitrile eluate upregulated expression levels in a significant manner. These findings suggest that factors originating from brain tissue are involved in ovarian maturation, but that the thoracic ganglia do not likely harbor significant quantities of stimulatory substances. In the future, this knowledge may be useful in developing technology for inducing maturation and spawning in captive female penaeid. [ABSTRACT FROM AUTHOR]