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Animal Source Foods
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Coloration or pigmentation in animals mediates the relationship between an organism and its environment in important ways, including camouflage, mimicry, social signaling, antipredator defenses, parasitic exploitation, thermoregulation, and protection from ultraviolet light, microbes, and abrasion (5–6). Some aquatic animals such as fish, amphibians and cephalopods use pigmented chromatophores to provide camouflage. Pigmentation is used in signalization between animals, such as in courtship and sexual relation. For example, some cephalopods use their chromatophores to communicate. Across animals, coloration serves as a dynamic form of information (5–6).
Melanotropin Bioassays
Published in Mac E. Hadley, The Melanotropic Peptides, 2018
Mac E. Hadley, Ana Maria de L. Castrucci
Chromatophores present within the skin of teleost fishes have been used to evaluate the actions of many melanotropic substances. Erythrophores (red-colored pigment cells) present within scales of the European minnow, Phoxinus laevis, were, in fact, used to detect the presence of melanotropic peptides which are apparently elevated during pregnancy. This early “pregnancy” test was, therefore, a bioassay for melanotropic peptides. The responses of melanophores present within isolated scales or fins to hormones or other agents are now generally monitored by photometric methods11 rather than by the classical MI.
Pro-Opiomelanocortin In The Amphibian Pars Intermedia: A Neuroendocrine Model System
Published in Mac E. Hadley, The Melanotropic Peptides, 1988
Bruce G. Jenks, B. M. L. Lidy, Verburg-Van Kemenade, Gerard J. M. Martens
Most amphibians possess the remarkable ability to alter the color of their skin by altering the distribution of pigment in pigment-containing cells (chromatophores) of their integument. The dermal melanophores are most directly involved in the rapid changes of pigment distribution associated with background adaptation. The melanophores contain the black pigment, melanin, within pigment-filled granules, the melanosomes. In fully white-background- adapted animals, these granules are aggregated around the nuclei of the cells (melanophore index, MI = 1, see Figure 1), while in animals adapted to a black background, the melanosomes are dispersed throughout the cells (MI = 5), and consequently the skin takes on a dark coloration (reviewed by Bagnara and Hadley1). Early experiments showed the involvement of the pituitary gland in the regulation of pigment distribution. Removal of this gland in amphibians leads to a permanent paling of the skin.5, 6 The source of the factor stimulating dispersion proved to be the pars intermedia7,8 and hence, the hormone was called Intermedin, later to be replaced by the now more familiar name melanophore-stimulating hormone, MSH. The full significance of these early observations became clear through a series of classical experiments by Hogben and co-workers (reviewed by Waring2). These investigators showed that in the South African clawed toad, Xenopus laevis, a determining factor in the regulation of pigment dispersion in dermal melanophores is the fraction of overhead light which is reflected from the background, thus impinging on the upper retina (Figure 1). They proposed that this environmental cue ultimately regulates hormone secretion from the pituitary gland.
Synthesis, X-ray diffraction analysis, quantum chemical studies and α-amylase inhibition of probenecid derived S-alkylphthalimide-oxadiazole-benzenesulfonamide hybrids
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2022
Bilal Ahmad Khan, Syeda Shamila Hamdani, Muhammad Naeem Ahmed, Shahid Hameed, Muhammad Ashfaq, Ahmed M. Shawky, Mahmoud A. A. Ibrahim, Peter A. Sidhom
Drug discovery is a continuous challenge and keeps fascinating the researchers worldwide continuously regardless of the time and efforts required. Heterocycles, specially oxadiazoles, have been very important in drug discovery due to their important role in medicines. The use and demand of oxadiazoles motifs in drugs are increasing continuously and can be seen from their increasing number of patents filed, up to increase in 100% in last 10 years from 2000 to 2008, still this number is increasing on1. Nowadays, a considerable amount of drugs in use possess oxadiazole moiety, a few examples are zibotentan2–3, used for curing cancer, raltegravir, an important antiretroviral drug against HIV, and ataluren, used for the treatment of cystic fibrosis4. Oxadiazole rings help in fulfilling the dream of drug discovery in multiple ways, acting as an important part of pharmacophore, which stimulates the binding of chromatophore to ligand5, as a linker to fix the proper position of the substituent in space6 and help in controlling the molecular properties7. The importance of oxadiazole is not limited to the medicinal field but is also equally important in the industrial zone as a thermal stabiliser for polymer synthesis and has found wide applications in optics8–10. Many discoveries have proved oxadiazole motif has a broad range of pharmaceutical importance as an antidiabetic11, lipoxygenase inhibitor12, anti-inflammation13, anti-infection14, elastase inhibitors15, amylase inhibitor16, antibacterial17, antiobesity18, nonpeptidic procollagen C-proteinase inhibition19, anticancer20, and dipeptidyl peptidase IV inhibition21. Moreover, oxadiazoles are also reported to inhibit monoamine oxidase22, niacin receptor (GPR109A) agonist23, larvicide24, antifungal25, and glutaminyl cyclase inhibitors26.