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Evidence for a Thymus-Pineal Axis
Published in Nate F. Cardarelli, The Thymus in Health and Senescence, 2019
Ecdysone (ecdysone-α) and 20-hydroxyecdysone (ecdysone-β, ecdysterone) are found in adults with other ecdysteroids not present in the larval stages.195 20,26-Dihydroxyecdysone, for instance, is found only in the adult. During adult life, ecdysterones are synthesized in the ovaries of some, not all, insects.195,196 Function in the adult appears to be related to spermatogenesis, ovigenesis, and regulation of the corpora allata.
Phytoecdysteroids
Published in Amritpal Singh Saroya, Contemporary Phytomedicines, 2017
Phytoecdysteroids are plant-derived ecdysteroids. Phytoecdysteroids are a family of about 200 plant steroids related in structure to the invertebrate steroid hormone 20-hydroxyecdysone (Dinan 2001). Ecdysteroids are frequently detectable in leaves and flowers, but less so in stems, roots, and seeds (Dinan et al. 2001).Chemically, phytoecdysteroids are classed as triterpenoids, the group of compounds that includes triterpenesaponins, phytosterols, and phytoecdysteroids.
Significance of DopEcR, a G-protein coupled dopamine/ecdysteroid receptor, in physiological and behavioral response to stressors
Published in Journal of Neurogenetics, 2020
Emily Petruccelli, Arianna Lark, James A. Mrkvicka, Toshihiro Kitamoto
Another unanswered question is how DopEcR is activated by endogenous ligands, particularly ecdysteroids. Adult Drosophila can synthesize ecdysteroids within the female ovary (Domanitskaya et al., 2014; Gaziova et al., 2004) and from Malpighian tubules in response to desiccation stress (Zheng et al., 2018), but other adult tissues that produce and release ecdysteroids requires further investigation. The developmental release of ecdysone from the steroidogenic prothoracic gland is similar to that of neurotransmitters from neurons, mediated by calcium-regulated vesicular trafficking (Yamanaka, Marqués, & O’Connor, 2015). This raises the interesting possibility that ecdysteroids are synthesized and stored in neurosecretory cells, and released as neurosteroids in an activity-dependent manner.
Probing the settlement signals of Amphibalanus amphitrite
Published in Biofouling, 2018
Mado Kotsiri, Maria Protopapa, Gesthimani-Myrto Roumelioti, Athena Economou-Amilli, Eleni K. Efthimiadou, Skarlatos G. Dedos
Much less studied in barnacles (Høeg et al. 2015), but firmly established in insects (Hartenstein and Chipman 2015), hormonal regulation of metamorphic events dominates the life cycles of arthropods. The interplay between juvenile hormone (JH) and ecdysteroids, as first established in insects, has also been found to apply to sessile arthropods including barnacles (Yamamoto, Kawaii, et al. 1997; Aldred and Clare 2008; Høeg et al. 2015). Research on a model cirripede species, Amphibalanus (=Balanus) amphitrite (Clare and Høeg 2008), showed that methyl farnesoate (MF), a structural variant of insect JH III (Yamamoto, Okino, et al. 1997; Smith et al. 2000) or 20-hydroxyecdysone (20E) (Clare et al. 1992; Yamamoto, Kawaii, et al. 1997) produce a concentration-dependent effect on the development of cyprids of A. amphitrite and impede, in the case of MF, their settlement behaviour by inducing developmental abnormalities (Yamamoto, Kawaii, et al. 1997). Conversely, in the case of 20E, acceleration of settlement behaviour is observed which expedites their metamorphic process (Clare et al. 1992). These two hormones regulate temporal gene expression events that determine the phenotypic outcome of the metamorphic event, but very little is known in barnacles about the signalling cascades that modulate or are modulated by the titres of these hormones. The process of surface exploration and the ensuing metamorphosis bears a striking resemblance to the wandering and cocoon spinning process of insects, which is soon followed by pupal metamorphosis, with the exception that the cyprid stage in barnacles is equivalent to the pupal stage of insects. This analogy helps as a paradigm shift in creating a universal concept of arthropod development.
Formulation and characterisation of Azadirachta indica nanobiopesticides for ecofriendly control of wheat pest Tribolium castaneum and Rhyzopertha dominica
Published in Journal of Microencapsulation, 2022
Humaira Iqbal, Nazish Jahan, Saba Jamil
Neem plant showed pesticidal effect due to the presence of azadirachtin (Active component) which indicated antifeedant property (Selvaraj and Mosses 2011, Tiwari et al.2014). In this study, the extract of A. indica leaves was prepared in ethanol solvent. The various types of bioactive components like terpenoids, flavonoids, saponins, tannins, glycosides, alkaloids, and phenols were reported in ethanol extract of A. indica (Pandey et al.2014, Sharma et al. 2014, Raissa et al. 2019). Basically, in these classes of compounds, terpenoids were examined as a key component for pesticidal activity (Islas et al.2020). In the literature data, the tetranotriterpenoid limonoids like azadirachtin, salannin, and nimbin were identified in the ethanolic extract of A. indica (Chaudhary et al.2017, Cesa et al.2019, Kaushik 2019, Pascoli et al.2019). In the same context, the nanosuspensions were prepared with ethanolic extract of A. indica, so the active ingredients of A. indica-based nanobiopesticides were azadirachtin, salannin, and nimbin. These components have a toxic effect on pests and destroy the structure of the alimentary canal and integument causing disorderliness in extracellular membrane layers and the basal portion of stomach epithelial cells (Castillo et al.2010, Akihisa et al.2011). They also inhibit the production and release of moulting hormones (ecdysteroids) from the prothoracic gland, leading to partial ecdysis in pests (Majambere et al.2007). Azadirachtin particularly inhibits the activity of the acetylcholinesterase enzyme. Neem-based active compounds bind to the active site of this enzyme, resulting in reversible competitive inhibition (Campos et al.2019).