Farnesoic Acid Research Articles

Molecular signature of the ontogenic development of the prawn Macrobrachium tenellum

The prawn Macrobrachium tenellum shows aquaculture potential due to its well-defined reproductive cycle linked to female nutritional requirements. Significant changes occur in egg composition during the 16 to 17-day embryo development. Understanding the ontogenic proteins is crucial for developmental insights and controlled reproduction. We employed free-label quantitative proteomics to analyze egg peptides at the initial and final stages of wild females. Using the emPAI protocol and Proteome Discoverer 2.0, we identified 89 differentially expressed proteins in M. tenellum eggs. Of these, 27 were exclusive to early-stage development and three to late-stage. Abundant proteins included Vitellogenin, glyceraldehyde-3-phosphate dehydrogenase, histone 4, beta-actin, and hemocyanin. Gene Ontology analysis revealed 518 terms across molecular functions, biological processes, and cellular components using the GoRetriever tool of AgBase and the CateGOrizer tool of the Animal Genome Research Program. Carbohydrate metabolism was significant in early-stage development, with glyceraldehyde-3-phosphate dehydrogenase being the second most abundant protein. Proteins involved in ATP synthesis and cytoplasmic proteins associated with catalytic and binding activities related to primary metabolism were also detected. Our study elucidates the role of Vitellogenin in lipid transport activity and its potential involvement in the juvenile hormone feedback pathway. This pathway includes farnesoic acid O-methyltransferase and juvenile hormone epoxide oxidase, regulating protein biosynthesis, molt cycles (including chitinase activity), and potentially influencing controlled reproduction. Our proteomic analysis provides insights into the molecular mechanisms driving Ontogenic development in Macrobrachium tenellum, with implications for controlled reproduction strategies and advancements in aquaculture practices.

Possible Regulation of Larval Juvenile Hormone Titers in Bombyx mori by BmFAMeT6.

Juvenile hormone (JH) plays a vital role in the growth, development, and reproduction of insects and other arthropods. Previous experiments have suggested that BmFAMeT6 could affect the duration of the silk moth's larval stage. In this study, we established the BmFAMeT6 overexpression strain and BmFAMeT6 knockout strain using the GAL4/UAS binary hybrid system and CRISPR/Cas 9 system, respectively, and found that the larval stage of the overexpression strain was shorter, while the knockout strain was longer. Our results exhibited that both the JH titers and BmKr-h1 levels in the larvae of the third instar were reduced significantly by BmFAMeT6 overexpression, but were increased obviously by BmFAMeT6 knockout. In addition, injection of farnesoic acid induced changes in the JH I and JH II levels in the hemolymphs of larvae. This study is the first to directly reveal the role of BmFAMeT6 in the regulation of insect JH titers and the relationship between farnesoic acid and JH (JH I and JH II). This provides a new perspective on regulating the growth and development of insects such as Bombyx mori.

Target gene selection for RNAi-based biopesticides against the hawthorn spider mite, Amphitetranychus viennensis (Acari: Tetranychidae).

Recently, RNA interference (RNAi)-based biopesticide, a species-specific pest control alternative, has been deregulated and commercialized in the US and Canada. The hawthorn spider mite, Amphitetranychus viennensis Zacher, is a major pest for rosaceous plants, which has been controlled primarily by synthetic pesticides. To address the emerging resistance issues in A. viennensis, we initiated a project to develop RNAi-based biopesticides. In this study, we (i) developed a dietary RNAi system for A. viennensis using leaf disc, (ii) assessed the suitability of multiple control genes to distinguish sequence-specific silencing from non-specific effects within this RNAi system, and (iii) screened for the target gene candidates. As a result, β-Glucuronidase (GUS), an enzyme derived from E. coli and a broadly used reporter for plants is the appropriate control for A. viennensis RNAi, while green fluorescent protein (GFP), is not suitable due to its significantly higher mortality than the other controls. For target gene screening, suppression was confirmed for all the candidates, including two housekeeping genes (Vacuolar-type H + -ATPase subunit A (V-ATPase A) and Glyceraldehyde 3-phosphate dehydrogenase, (GAPDH)), and three genes associated with development (ATP-dependent RNA Helicase DDX3Y (Belle), CREB-binding protein (CBP), and Farnesoic acid O-methyltransferase (FaMet)). Knocking down of V-ATPase A resulted in the highest mortality (~ 90%) and reduced fecundity (over 90%) than other candidates. As for the genes associated with development, suppression of Belle and CBP, led to approximately 65% mortality, as well as 86% and 40% reduction in fecundity, respectively. Silencing of FaMet, however, had negligible biological impacts on A. viennensis. The combined efforts not only establish an effective dsRNA delivery method, but also provide potential target genes for RNAi-based biopesticides against A. viennensis, a devastating invasive pest for fruit trees and woody ornamental plants throughout Asia and Europe. © 2023 Society of Chemical Industry.

Sesquiterpenoid pathway in the mandibular organ of Penaeus monodon: Cloning, expression, characterization of PmJHAMT and its alteration response to eyestalk ablation

Methyl farnesoate (MF), a crustacean equivalent of juvenile hormone (JH) of insects, is known to be produced from the mandibular organ (MO). This study reports transcriptome analysis of Penaeus monodon MO and identifies putative genes encoding enzymes in the sesquiterpenoid pathway. A total of 44,490,420 clean reads were obtained and utilized for subsequent analysis. De novo assembly created 31,201 transcripts and 31,167 unigenes. To archive the functional annotation, all unigenes were annotated with KOG, KEGG, and GO. Putative genes encoding enzymes and regulatory proteins involved in the sesquiterpenoid pathway were obtained from the MO transcriptome data based on the conserved domains and sequence homology. They included S-adenosylmethionine synthetase, farnesyl pyrophosphate synthase, short chain dependent dehydrogenase/reductase (SDR), NAD(P) + -dependent aldehyde dehydrogenase, S-adenosylmethionine-dependent methyltransferases or juvenile hormone acid-O-methyl transferase (JHAMT), farnesoic acid O-methyl transferase (FAMeT), juvenile hormone binding protein, cytochrome C/P-450 family 15 (CRYP15A1)/methylfarnesoate epoxidase (MFE), juvenile hormone epoxide hydrolase (JHEH), and juvenile hormone esterase (JHE). We first identified and characterized JHAMT orthologs inP. monodon(PmJHAMT). The complete cDNA sequence ofPmJHAMTconsisted of 1,221 nt encoded 271 amino acids with a conserved S-adenosyl methionine (SAM) binding domain. Phylogenetic analysis clusteredPmJHAMTinto the group JHAMT with the same clade of the crabPortunus trituberculausJHAMT. Moreover, the predicted three-dimensional structure of PmJHAMT showed remarkable similarity with the recent crystal structure ofthe Bombyx moriJHAMT homodimer. RT–PCR analysis revealed that PmJHAMT was exclusively expressed in MO and initially expressed at stage 3 postlarvae. In situ hybridization with a specific probe to PmJHAMT validated the specific expression of this gene in MO cells. Finally, we evaluated the regulation of MO by eyestalk inhibitory peptides. Diminishing MO inhibitory hormone through unilateral eyestalk ablation resulted in a significantly higher expression ofPmJHAMTin MO by quantitative PCR. This result indicated that the eyestalk inhibitory hormone inhibited MF synthesis byPmJHAMTgene suppression in the MO. This finding provides insight into the crustacean sesquiterpenoid pathway and improves our understanding of crustacean endocrinology.

Structural characterization and functional analysis of juvenile hormone acid methyltransferase JHAMT3 from the silkworm, Bombyx mori

Juvenile hormone acid methyltransferase (JHAMT) is a rate-limiting enzyme of juvenile hormone (JH) biosynthesis in insects. It transfers the methyl group of S-adenosyl methionine to either the carboxyl group of JH acids or farnesoic acid to produce JH. Six JHAMT paralogues have been identified in the silkworm (Bombyx mori); among them, JHAMT1 and JHAMT2 display a methyltransferase activity. Here, the three-dimensional crystal structure of inactive JHAMT3 and the binary complex of JHAMT3 with its cofactor S-adenosyl-l-homocysteine were determined through X-ray crystallization. Comparative structural analysis revealed that JHAMT3 adopted a similar structural pattern to that of functional JHAMT2, which comprised one core Rossmann fold domain and one substrate-binding domain. Similar to JHAMT2, JHAMT3 underwent a conformational change at the Rossmann fold domain because of cofactor binding, which promoted ligand accommodation. However, it exhibited a relatively rigid substrate-binding pocket compared with that of JHAMT2. JHAMT3 was also highly expressed in the silk gland of fourth- and fifth-instar B. mori larvae. The results of expression profiling combined with activity analysis suggested that JHAMT3 might function as a binding protein of JH acids for the regulation of JH acid titers. These findings provide a structural basis for enhancing the understanding of the physiological function of JHAMT3 and a rational framework for the development of potent and specific inhibitors of JHAMT family members.

Cloning and Characterization of Drosophila melanogaster Juvenile Hormone Epoxide Hydrolases (JHEH) and Their Promoters

Juvenile hormone epoxide hydrolase (JHEH) plays an important role in the metabolism of JH III in insects. To study the control of JHEH in female Drosophila melanogaster, JHEH 1, 2 and 3 cDNAs were cloned and sequenced. Northern blot analyses showed that the three transcripts are expressed in the head thorax, the gut, the ovaries and the fat body of females. Molecular modeling shows that the enzyme is a homodimer that binds juvenile hormone III acid (JH IIIA) at the catalytic groove better than JH III. Analyses of the three JHEH promoters and expressing short promoter sequences behind a reporter gene (lacZ) in D. melanogaster cell culture identified a JHEH 3 promoter sequence (626 bp) that is 10- and 25-fold more active than the most active promoter sequences of JHEH 2 and JHEH 1, respectively. A transcription factor (TF) Sp1 that is involved in the activation of JHEH 3 promoter sequence was identified. Knocking down Sp1 using dsRNA inhibited the transcriptional activity of this promoter in transfected D. melanogaster cells and JH III and 20HE downregulated the JHEH 3 promoter. On the other hand, JH IIIA and farnesoic acid did not affect the promoter, indicating that JH IIIA is JHEH’s preferred substrate. A transgenic D. melanogaster expressing a highly activated JHEH 3 promoter behind a lacZ reporter gene showed promoter transcriptional activity in many D. melanogaster tissues.

Rethinking Sesquiterpenoids: A Widespread Hormone in Animals.

The sesquiterpenoid hormone juvenile hormone (JH) controls development, reproduction, and metamorphosis in insects, and has long been thought to be confined to the Insecta. While it remains true that juvenile hormone is specifically synthesized in insects, other types or forms of sesquiterpenoids have also been discovered in distantly related animals, such as the jellyfish. Here, we combine the latest literature and annotate the sesquiterpenoid biosynthetic pathway genes in different animal genomes. We hypothesize that the sesquiterpenoid hormonal system is an ancestral system established in an animal ancestor and remains widespread in many animals. Different animal lineages have adapted different enzymatic routes from a common pathway, with cnidarians producing farnesoic acid (FA); non-insect protostomes and non-vertebrate deuterostomes such as cephalochordate and echinoderm synthesizing FA and methyl farnesoate (MF); and insects producing FA, MF, and JH. Our hypothesis revolutionizes the current view on the sesquiterpenoids in the metazoans, and forms a foundation for a re-investigation of the roles of this important and yet neglected type of hormone in different animals.

Comparative Metabolomics and Lipidomics of Four Juvenoids Application to Scylla paramamosain Hepatopancreas: Implications of Lipid Metabolism During Ovarian Maturation

This study was the first to evaluate multiple hormonal manipulations to hepatopancreas over the ovarian development stages of the mud crab, Scylla paramamosain. A total of 1258 metabolites in 75 hepatopancreas explants from five female crabs were induced by juvenile hormone III (JH III), methyl farnesoate (MF), farnesoic acid (FA) and methoprene (Met), as identified from combined metabolomics and lipidomics (LC-MS/MS). 101 significant metabolites and 47 significant pathways were selected and compared for their comprehensive effects to ovarian maturation. While MF played an extensive role in lipid accumulation, JH III and Met shared similar effects, especially in the commonly and significantly elevated triglycerides and lysophospholipids (fold change≥2 and ≤0.5, VIP≥1). The significant upregulation of β-oxidation and key regulators in lipid degradation by FA (P ≤ 0.05) resulted in less lipid accumulation from this treatment, with a shift toward lipid export and energy consumption, unlike the effects of MF, JH III and Met. It was possible that MF and FA played their own unique roles and acted in synergy to modulate lipid metabolism during crab ovarian maturation. Our study yielded insights into the MF-related lipid metabolism in crustacean hepatopancreas for the overall regulation of ovarian maturation, and harbored the potential use of juvenoids to induce reproductive maturity of this economic crab species.

Cloning, expression analysis and RNAi of farnesoic acid O-methylransferase gene from Neocaridina denticulata sinensis.

Methyl farnesoate (MF) is an essential endocrine hormone in crustaceans, which can promote the occurrence of crustaceans molting, control morphogenesis, affect gonad development, and regulate the stress stimulation to the external environment. The farnesoic acid O-methyltransferase (FAMeT) is a key rate-limiting enzyme in MF synthesis, catalyzing the conversion of farnesoic acid (FA) into MF. Neocaridina denticulata sinensis [Decapoda] is a suitable animal model for studying crustaceans because it can reproduce many times under artificial control and has a short reproductive cycle. According to its transcriptomic and genomic information, the full-length cDNA sequence of FAMeT from N. denticulata sinensis (NdFAMeT) was cloned and the characterization of its deduced amino acid sequence was also analyzed. The relative expression of NdFAMeT in different tissues was determined. The NdFAMeT protein was recombinantly expressed in E. coli and its enzyme activity was determined. After gene knockdown by RNAi technology, the protein activity of shrimp was decreased and the individual phenotype was also observed.

A simple validated HPTLC method for the analysis of flavonoids and molecular docking studies of novel tri-terpenoid glycoside isolated from Carya illinoinensis bark with potential anti-inflammatory and antinociceptive activities

Carya illinoinensis (Family Juglandaceae) is frequently used in traditional medicine for its antimicrobial, antioxidant, anti-rheumatic, anti-diabetic, and diuretic activities. Column chromatography was used to separate phytoconstituents from an ethanolic extract of powered bark. The terpenoid glycosidic compound, CI-01, was isolated as light-yellow crystalline powder in 0.33% (w/w) yield having melting point 94–96 °C, RF value 0.57 (in MeOH:CHCl3;20:80), UV absorption maxima 242 nm in methanol and molecular ion [M + H]+ peak at 420.4 m/z. Based on high-performance thin-layer chromatography and spectral data, the isolated compound CI-01, was identified as Farnesoic acid -l-glucoside. The ethanolic extract of Carya illinoinensis (CIE) at doses of 100 and 200 mg/kg and isolated compound CI-01 at 10 mg/kg dose were used for studying anti-inflammatory and antinociceptive effects. After 5 h of treatment with CI-01, the mean increase in paw volume was 0.459 ± 0.054 ml, which is corresponding to the standard drug indomethacin's 0.443 ± 0.041 ml. However, CIE groups receiving 100 and 200 mg/kg exhibited 0.518 ± 0.068 and 0.486 ± 0.048 ml, respectively. Compared to the control group of mice, animals treated with CIE and CI-01 dramatically reduced the number of writhes caused by acetic acid. AutoDock Vina program was used for molecular docking of the compound CI-01 with various targets, including COX-1, COX-2, inducible nitric oxide synthase, tumor necrosis factor-α, and opioid receptors exhibiting mean binding energies of -5.36, -7.37, -7.24, -4.27, and -7.04 kcal/mol, respectively. In conclusion, CI-01, isolated from Carya illinoinensis extract, demonstrated anti-inflammatory and antinociceptive activities at a dose of 10 mg/kg and displayed promising interaction with COX-2 in molecular docking study.

Genomic Identification and Functional Analysis of JHAMTs in the Pond Wolf Spider, Pardosa pseudoannulata.

Juvenile hormone (JH) plays a critical role in many physiological activities of Arthropoda. Juvenile hormone acid methyltransferase (JHAMT) is involved in the last steps of JH biosynthesis as an important rate-limiting enzyme. In recent studies, an increasing number of JHAMTs were identified in arthropods, but no JHAMT was reported in spiders. Herein, eight JHAMTs were identified in the pond wolf spider, Pardosa pseudoannulata, all containing the well conserved S-adenosyl-L-methionine binding motif. JHAMT-1 and the other seven JHAMTs were located at chromosome 13 and chromosome 1, respectively. Multiple alignment and phylogenetic analysis showed that JHAMT-1 was grouped together with insect JHAMTs independently and shared high similarities with insect JHAMTs compared to the other seven JHAMTs. In addition, JHAMT-1, JHAMT-2, and JHAMT-3 were highly expressed in the abdomen of spiderlings and could respond to the stimulation of exogenous farnesoic acid. Meanwhile, knockdown of these three JHAMTs caused the overweight and accelerated molting of spiderlings. These results demonstrated the cooperation of multi-JHAMTs in spider development and provided a new evolutionary perspective of the expansion of JHAMT in Arachnida.

Molecular evidence for farnesoic acid O-methyltransferase (FAMeT) involved in the biosynthesis of vitellogenin in the Chinese mitten crab Eriocheir sinensis

Sesquiterpenoid methyl farnesoate (MF), a crustacean equivalent of insect juvenile hormone (JH III), has essential functions in regulating physiological processes in crustaceans, including reproduction and vitellogenesis. Farnesoic acid O-methyltransferase (FAMeT) is a key rate-limiting enzyme catalyzing the conversion of farnesoic acid (FA) to JH/MF in insects and crustaceans. In this study, a full-length cDNA of EsFAMeT from Eriocheir sinensis was isolated and characterized. The deduced EsFAMeT amino acid sequence indicated there were two conserved Methyltransf-FA domains characteristic of FAMeT family proteins. With use of sequence alignment analysis procedures, there was an indication that FAMeT proteins are highly conserved among crustaceans and FAMeT is more closely related to crustacean FAMeT than to insect FAMeT. Results from quantitative real-time PCR analysis revealed there was ubiquitous EsFAMeT in all tissues examined, with greater abundances of mRNA transcripts in the ovary. The transcription of EsFAMeT indicated there were stage-specific patterns in the hepatopancreas and ovary during ovarian development, with the greatest abundance during ovarian development Stages II and III, respectively. To investigate functions of EsFAMeT in vitellogenin biosynthesis in E. sinensis, RNA interference-mediated gene knockdown was used in vitro and in vivo. Injection of EsFAMeT dsRNA resulted in a marked decrease in EsVg (encoding vitellogenin) transcripts in the ovary and hepatopancreas both in vitro and in vivo. Results from the present study indicated EsFAMeT is involved in vitellogenin biosynthesis in the ovary and hepatopancreas of E. sinensis, providing a new resource to study modulatory effects of the FAMeT family of enzymes in crustacean reproduction.

Effect of methyl farnesoate and farnesoic acid during 5th zoea and megalopa metamorphosis in the mud crab Scylla paramamosain Estampador, 1950 (Decapoda, Brachyura, Portunidae)

Abstract The mud crab Scylla paramamosain is one of the economically important aquaculture species in China. The larval development of the mud crab is characterized by two significant morphological changes, from the 5th zoea (Z5) to the megalopa (M) stage and from the M to the first juvenile crab (C1) stage. In this study, we found that methyl farnesoate (MF) could prohibit the Z5 to M metamorphosis in a concentration-dependent manner, and that a concentration of 10 μM MF could completely prohibit the Z5 metamorphosis. Farnesoic acid (FA) could also prohibit the Z5 metamorphosis, but its effects seemed to be concentration-independent. In addition, MF could delay rather than prohibit the M to C1 metamorphosis, while FA had no effect on the M to C1 metamorphosis at all. To summarize, it is hypothesized that either absence of MF and FA, or at least very low levels of these substances, might be necessary for a successful Z5 to M metamorphosis.

Farnesoic acid methyltransferase 6 (BmFAMeT6) interrelates with moltinism of dominant trimolter in silkworm, Bombyx mori

Silkworm moltinism is closely related to many important economic characters such as cocoon yield and cocoon filament size. Farnesoic acid methyltransferase (FAMeT) is the rate-limiting enzyme for the conversion of farnesoic acid to methyl farnesoate which acts as juvenile hormone in crustaceans. Silkworm has seven FAMeT genes in its genome but the precise role of BmFAMeT is still unclear. Our results showed that BmFAMeT6 expression had a clear difference between two different moltinism strains, the M3/M3 (dominant trimolter) and the +M/+M (tetramolter). Declining BmFAMeT6 expression in the M3/M3 could increase the number of larval molts/instars and convert trimolter to tetramolter, and injecting dsBmFAMeT6 could significantly improve the tetramolter rate in several other dominant trimolter strains. These data demonstrated that BmFAMeT6 is relevant to the moltinism of the dominant trimolter. Interestingly, BmFAMeT6 expression was high at the early larval stage and low at the final instar. BmFAMeT6 protein signal was stronger on the first day than on the second day within each instar and was very weak at the last larval instar. BmFAMeT6-specific fluorescence was localized on the corpus allatum. It suggests a correlation between BmFAMeT6 expression and juvenile hormone titers. We speculated that decreasing BmFAMeT6 could affect the moltinism in the dominant trimolter, which may be interrelated with the close relationship between BmFAMeT6 and juvenile hormone titers in silkworm.

Purification, biochemical characterisation and bioinformatic analysis of recombinant farnesol dehydrogenase from Theobroma cacao

The juvenile hormones (JH) in plants are suggested to act as a form of plant defensive strategy especially against insect herbivory. The oxidation of farnesol to farnesoic acid is a key step in the juvenile hormone biosynthesis pathway. We herein present the purification and characterisation of the recombinant Theobroma cacao farnesol dehydrogenase enzyme that catalyses oxidation of farnesol to farnesal. The recombinant enzyme was purified to apparent homogeneity by affinity chromatography. The purified enzyme was characterised in terms of its deduced amino acid sequences, phylogeny, substrate specificity, kinetic parameters, structural modeling, and docking simulation. The phylogenetic analysis indicated that the T. cacao farnesol dehydrogenase (TcFolDH) showed a close relationship with A. thaliana farnesol dehydrogenase gene. The TcFolDH monomer had a large N-terminal domain which adopted a typical Rossmann-fold, harboring the GxxGxG motif (NADP(H)-binding domain) and a small C-terminal domain. The enzyme was a homotrimer comprised of subunits with molecular masses of 36 kDa. The TcFolDH was highly specific to NADP+ as coenzyme. The substrate specificity studies showed trans, trans-farnesol was the most preferred substrate for the TcFolDH, suggesting that the purified enzyme was a NADP+-dependent farnesol dehydrogenase. The docking of trans, trans-farnesol and NADP+ into the active site of the enzyme showed the important residues, and their interactions involved in the substrate and coenzyme binding of TcFolDH. Considering the extensive involvement of JH in both insects and plants, an in-depth knowledge on the recombinant production of intermediate enzymes of the JH biosynthesis pathway could help provide a potential method for insect control.

Linolenic acid improves growth performance and immune status of Penaeus vannamei infected by Enterocytozoon hepatopenaei

Hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) leads to significant growth retardation of Penaeus vannamei and is increasing the economic losses in the shrimp aquaculture. Our previous metabolomic results showed that 24 metabolites including linolenic acid (LNA) significantly decreased in EHP-infected shrimp compared with healthy groups. This study aims to evaluate whether LNA can improve the growth performance and immune status of EHP-infected shrimp. The EHP-infected shrimp was fed with dietary LNA (0, 1.2, 2.4 and 4.8 g/kg diet) for 30 days. The results showed that compared to the other groups, the body length and weight of shrimp in groups of 2.4 g LNA/kg diet were significantly increased. The copy numbers of EHP were significantly reduced in group of 1.2, 2.4 and 4.8 LNA g/kg diet compared to without LNA group. Further study showed that when shrimp were fed with 2.4 g LNA/kg diet, growth-related genes (farnesoic acid O-methyltransferase and ecdysteroid-regulated protein) were down-regulated, but juvenile hormone esterase-like carboxylesterase 1 up-regulated, suggesting that LNA could improve the growth ability of EHP-infected shrimp. More importantly, three immune genes (peritrophin-44-like protein, lysozyme, and cathepsin C) in shrimp were significantly up-regulated after fed with addition of LNA. In addition, the enzyme activity of superoxide dismutase and catalase in the hepatopancreas of P. vannamei was obviously increased after fed with different concentrations of LNA. Overall, the appropriate LNA content in the feed (2.4 g/kg diet) can improve the growth of P. vannamei and enhance its non-specific immunity and antioxidant activity. These findings indicate that LNA could be used as a potential metabolic modulator for controlling the HMP caused by EHP, and shed some light on host metabolic prevention to infectious diseases.

Role of SfJHAMT and SfFAMeT in the reproductive regulation of Sogatella furcifera and its expression under insecticide stress

The isoprene branching pathway is a unique downstream synthesis pathway of juvenile hormone (JH) in arthropods, which plays an important role in the growth, development, and reproduction of insects. Juvenile hormone acid O-methyltransferase (JHAMT) and farnesoic acid O-methyltransferase (FAMeT) are two key proteins that are regulated in the isoprene branching pathway. Based on the available transcriptomic and genomic data of Sogatella furcifera, full-length cDNAs of SfJHAMT and SfFAMeT were identified. In vitro injection of dsRNA targeted to silence SfJHAMT and SfFAMeT inhibited the fecundity, ovarian development, and transcription levels of SfKr-h1 and SfVg significantly. Of note, The transcription levels of SfJHAMT and SfFAMeT are regulated mutually; i.e., silencing of SfJHAMT causes an increase in the SfFAMeT transcription level and vice versa, and the negative effect of simultaneous silencing on reproduction is greater. The results revealed a coordinated effect of SfJHAMT and SfFAMeT on the reproductive capabilities of S. furcifera. Furthermore, a JH analog (methoprene) partially rescued the negative effect of simultaneous silencing by SfJHAMT and SfFAMeT on reproduction. In addition, the expression profile analysis after insecticide stress showed that triazophos (LC25) can induce the transcription of SfMet and SfKr-h1 to promote JH signal transduction, which affects the transcription of SfVg and ultimately promotes the reproduction of S. furcifera. The results of the present study lay a foundation to further explain the isoprene branch pathway function in insect reproduction and can open up new avenues for sustainable pest control while expanding the current understanding of molecular mechanisms through which insecticides stimulate reproduction and lead to pest resurgence.

Diversity of Insect Sesquiterpenoid Regulation.

Insects are arguably the most successful group of animals in the world in terms of both species numbers and diverse habitats. The sesquiterpenoids juvenile hormone, methyl farnesoate, and farnesoic acid are well known to regulate metamorphosis, reproduction, sexual dimorphism, eusociality, and defense in insects. Nevertheless, different insects have evolved with different sesquiterpenoid biosynthetic pathway as well as products. On the other hand, non-coding RNAs such as microRNAs have been implicated in regulation of many important biological processes, and have recently been explored in the regulation of sesquiterpenoid production. In this review, we summarize the latest findings on the diversity of sesquiterpenoids reported in different groups of insects, as well as the recent advancements in the understanding of regulation of sesquiterpenoid production by microRNAs.

Integrative Proteomic and MicroRNA Analysis: Insights Into Mechanisms of Eyestalk Ablation-Induced Ovarian Maturation in the Swimming Crab Portunus trituberculatus.

Eyestalk ablation is the most common method to induce ovarian maturation in decapod crustacean aquaculture, but it jeopardizes broodstock survival and larvae production. It is important to understand the molecular basis underlying the maturation triggered by ablation and thereby develop an alternative measure for maturation manipulation. In this study, we investigate alterations of ovarian proteome and miRNA profile after ablation in a commercially important marine crab Portunus trituberculatus. Quantitative proteomic analysis using iTRAQ reveals that 163 proteins are differentially expressed following ablation, and modulation of methyl farnesoate metabolism and activation of calcium signaling may play important roles in the ovarian maturation induced by ablation. miRNA expression profiling identifies 31 miRNAs that show statistically significant changes. Integration of miRNA and proteome expression data with miRNA target prediction algorithms generates a potential regulatory network consisting of 26 miRNAs and 30 proteins linked by 71 possible functional associations. The miRNA-protein network analysis suggests that miRNAs are involved in promoting ovarian maturation by controlling expression of proteins related to methyl farnesoate synthesis, calcium signals, and energy metabolism. Experimental validation and temporal expression analysis indicate multiple miRNAs can act synergistically to regulate expression of Farnesoic acid O-methyltransferase and Calmodulin. Our findings provide new insights for elucidating the mechanisms underlying eyestalk ablation-induced ovarian maturation and could be useful for devising an alternative technique for manipulating reproduction in P. trituberculatus and other decapods.

Gammarid exposure to pyriproxyfen and/or cadmium: what effects on the methylfarnesoate signalling pathway?

Due to expected changes in climate, it is predicted that disease-carrying mosquitoes will expand their geographical range, resulting in increased use of insect growth regulators (IGRs) to face their proliferation. Among IGRs, pyriproxyfen (PXF) is widely used and has been shown to prevent larvae from developing into adults, rendering them unable to reproduce. However, because of the similarity of crustacean and insect endocrine systems, PXF could also impact aquatic crustaceans. In addition, when spreading in the environment, PXF is found in a mixture with other pollutants such as metallic trace elements, which could alter its effect. Consequently, the present work was devoted to analysing the effects of PXF on the methylfarnesoate (MF) hormonal pathway of the freshwater amphipod Gammarus pulex, as well as its combined binary effects with cadmium (Cd), by measuring MF concentration, as well as the relative transcriptional expression of the farnesoic acid O-methyltransferase (FAMeT) (enzyme limiting the MF production), the methoprene-tolerant receptor (Met), and the broad-complex (BrC) as a transcription factor. Results revealed that single exposures to PXF or Cd have mainly overexpressed FAMeT, Met, and BrC but did not significantly affect MF concentration. Conversely, the mixture exposures seemed to suppress these effects and even achieve antagonistic effects. This work confirmed that PXF single exposure could impact non-target organisms such as amphipods through changes in hormonal pathways of MF. In the same way, it highlighted that Cd could also impair the endocrine system of exposed organisms. However, antagonistic effects have been observed in exposure to mixtures, suggesting different long-term consequences on the growth of amphipods under realistic exposure conditions.