Influence of Dietary Supplements on Body Composition
Henry C. Lukaski in Body Composition, 2017
The creative claims of endocrine-based effects of dietary supplements are entertaining but are also easily debunked. For example, there are plant species that produce ecdysone-related substances to disrupt the physiology of their natural pest enemies. Ecdysone is a potent hormone involved in insect molting (ecdysis) and pupation. There are no known effects of insect molt hormones in humans, nor are there any known receptors for ecdysone action in humans; nevertheless, creative marketers easily conjure images of ecdysone-consuming body builders with Hulk-like cartoon characters and superhuman growth increases. At least one human study empirically tested these plant-derived ecdysone-based supplement claims and found no effects on body composition (Wilborn et al. 2006).
Toxicity and Chosen Behavioral and Physiological Effects of Some Tin Steroid Compounds on Selected Insect Species*
Nate F. Cardarelli in Tin as a Vital Nutrient:, 2019
This was examined on Ilnd instar larvae of A. aegypti. Once again, appropriate sublethal doses of both compounds had to be carefully determined in order to avoid toxic effects. The compounds were added in ethanol to water containing the test insects. The latter were provided with normal food as described earlier and observed throughout the successive molts until adult emergence. Records were maintained of the period taken for completion of development for both the treated and untreated (control) replicates. Larval/pupal mortality, failure of ecdysis, inhibition of adult emergence, and/or any other anomaly were carefully recorded.
An Overview of Parasite Diversity
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2015
Among those animals with bilateral symmetry, in addition to a number of smaller phyla whose affinities are debated, three major lineages of animals are recognized, as indicated by the colors in Figure 2.16: the Deuterostomia, Lophotrochozoa, and the Ecdysozoa. Molecular studies have been particularly important in defining this last major lineage, one united by the common property of molting (ecdysis) of an external cuticle. The Guinea worm, Dracunculus medinensis (Figure 2.17A), a member of the phylum Nematoda that includes many parasitic representatives, is an example of an animal that undergoes molting (Ecdysozoa). This species is now on the verge of eradication owing to control measures to break its life cycle by filtering drinking water and preventing ingestion of infected copepods (see Chapter 9). Also included among the molting phyla is a huge group of organisms, the Arthropoda. Included prominently in the Arthropoda are the insects. The Arthropoda include several other groups with many parasite species such as Sarcoptes scabiei, a mite that causes intense itching when it tunnels through human skin (Figure 2.17B). More specifically, it is a chelicerate arthropod meaning it has pincerlike chelicerae instead of jaws. Many species of mites are parasitic. Another prominent group of arthropods are the crustaceans, many of which are parasitic, often becoming highly modified in form in the process of becoming parasitic (Figure 2.17C). Prominent among the Lophotrochozoa are members of the phylum Platyhelminthes, most of which are parasitic. One spectacular example is Taenia saginata, a tapeworm that routinely grows to 4 to 12 meters in length, living in the small intestine of its human host (Figure 2.17D).
Body condition and energy content of the shore crab Carcinus maenas L. in a temperate coastal system: the cost of barnacle epibiosis
Published in Biofouling, 2022
Joana Campos, Felipe Ribas, Ana Bio, Vânia Freitas, Allan T. Souza, Henk W. van der Veer
Dealing with epibiosis generally involves trade-offs between tolerance and investment into defence, which utilises resources of the host (Auker et al. 2014; Leonard et al. 2017). Often costs of epibionts outweigh their benefits for the basibiont (e.g. Wahl 1989, 1997; Becker et al. 2000; Buschbaum and Saier 2001). Therefore, many organisms have behavioural and/or physiological antifouling mechanisms (Becker and Wahl 1996; Fernandez-Leborans 2010) to shed epibionts by grooming, or preventing them from initially attaching, by hiding and burrowing, or using bioactive compounds like surface waxes, and cuticular structures (e.g. Gili et al. 1993; Becker and Wahl 1996; Wahl et al. 1998). In crustaceans, ecdysis is an effective way of removing any existing epibionts (Dyrynda 1986; Thomas et al. 1999). Crustaceans also secrete waxes onto their cuticles, reducing cuticular wettability and possibly making it harder for epibionts to adhere (Becker et al. 2000; Callow and Callow 2002). Also, the microtopography of the cuticle can prevent colonization or growth (Callow and Callow 2002; Bers and Wahl 2004). Nevertheless, in energy-limited conditions, producing such defences can be costly (Fagerstrom 1989) and hence tolerating epibionts releases energy reserves otherwise invested in growth or reproduction (Bazzaz et al. 1987; Van Alstyne 1988).
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
An additional question left to be addressed concerns the possible role of DopEcR in Drosophila development. Ecdysis (molting) is arguably a stressful event. Many arthropods become behaviorally quiescent before a molt, suggesting that ecdysteroid changes muscle excitability. In support of this, ecdysteroid application to the larval neuromuscular junction (NMJ) acutely reduced the size of postsynaptic currents by reducing the number of synaptic vesicles released by motor neurons, but not changing quantal content (Cooper & Ruffner, 1998; Ruffner, Cromarty, & Cooper, 1999). To the best of our knowledge, the role of DopEcR in this context has not yet been investigated.
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).
Related Knowledge Centers
- Cuticle
- Ecdysone
- Exoskeleton
- Gastrointestinal Tract
- Moulting
- Regeneration
- Trachea
- Integumentary System
- Apolysis
- Hormone