1,721,041 research outputs found
Erratum to: Oligomycin A and the IPLB-LdFB insect cell line: Actin and mitochondrial responses [32 (2) 287-292] (DOI:10.1016/j.cellbi.2007.10.011)
No full textAmyloid/Melanin distinctive mark in invertebrate immunity
No full textProtostomes and Deuterostomes show the same nexus between melanin production, and amyloid
fibril production, i.e., the presence of melanin is indissolubly linked to amyloid scaffold that, in turn, is
conditioned by the redox status/cytoplasmic pH modification, pro-protein cleavage presence,
adrenocorticotropin hormone (ACTH), melanocyte-stimulating hormone (α-MSH), and neutral
endopeptidase (NEP) overexpressions. These events represent the crucial component of immune
response in invertebrates, while in vertebrates these series of occurrences could be interpreted as a
modest and very restricted innate immune response. On the whole, it emerges that the mechanisms
involving amyloid fibrils/pigment synthesis in phylogenetically distant metazoan (viz, cnidaria,
molluscs, annelids, insects, ascidians and vertebrates) are evolutionary conserved. Furthermore, our
data show the relationship between immune and neuroendocrine systems in amyloid/melanin
synthesis. Indeed the process is closely associated to ACTH-α-MSH production, and their role in
stress responses leading to pigment production reflects and confirms again their ancient phylogeny
Annelida: Hirudinea (Leeches): Heterogeneity in Leech Immune Responses
No full textThe chapter provides a comprehensive picture of some of the most significant information on the type of cells and mechanisms involved in the regulation of the inflammation, immune response and tissue regeneration processes in the medicinal leech. This Annelid represents a useful experimental model to investigate the immune system, being cost-effective, easily manipulable and devoid of significant ethical considerations and regulatory restrictions in relation to its use. Moreover, this invertebrate model shows an innate immune response and a wound healing process characterized by the same responses observed in vertebrates, involving the same cellular mechanisms and also the same types of molecules - as specific growth factors - playing a pivotal role for guiding, controlling and regulating the angiogenesis and the innate immune response
Amyloid and allorecognition in the colonial ascidian Botryllus schlosseri.
Full text linkAllorecognition, i.e., the ability of intraspecific nonself recognition is widely distributed among colonial, sessile marine organisms in the form of colony specificity. In the cosmopolitan compound ascidian Botryllus schlosseri, colony specificity is controlled by a highly polymorphic Fu/HC locus: two colonies sharing at least one alleleat the Fu/HC locus can fuse into a chimeric colony; if no alleles are shared, a typical inflammatory reaction occurs, with the recruitment of a specific hemocyte type, the cytotoxic morula cells (MCs), inside the tips of the ampullae (the blind termini ofthe tunic vasculature) extending towards the alien colony, their extravasation in the tunic and their final degranulation. As a consequence of allorecognition, necrotic, melanic spots (points of rejection; PORs) form along the contact border, due to the release, by MCs, of their granular content, mainly represented by quinones, polyphenols and the enzyme phenoloxidase (PO), upon the perception of the allogeneic humoral factors diffusing from the alien colony through the partially fused tunics. It is remarkable that the deposition of melanin and the cell death is confined to the immediate outside of the ampullar tips, suggesting that the diffusion of PO and the products of its activity are, in some way, prevented in order to limit cytotoxicity to the immediate neighbourhood of the contact region. In this context, we looked for factors released by MCs that could limit the spreading of cytotoxicity and melanisation. We found that MCs share with vertebrate melanocytes similar packaging of melanin precursors, entrapped in a 3Dscaffold of amyloid fibrils. They contribute to form the electron dense content of MC granules that, after stimulation, flake off and is released in the surrounding medium. Released amyloid fibrils limit the diffusion of the produced melanin. The search for genes and factor controlling both melanogenesis and amyloidogenesis, revealed an evolutionary conserved machinery involved in the processes and an unexpected cross talk between the two Botryllus immunocyte types, i.e., phagocytes and MCs. Furthermore, this work confirms the physiological role of amyloid in tunicate immunity
Time-related changes of hemocyte morphology in the gastropod Pomacea canaliculata. XIV Meeting of the Italian Association of Developmental and Comparative Immunology, Palermo, Inv. Surv. J., 10: 21, 2013.
No full textTime-related changes of hemocyte morphology in the gastropod Pomacea canaliculat
Heliothis virescens/Toxoneuron nigriceps: parasitoid strategies for successful endoparasitic development
No full textPhenoloxidase, melanin and amyloid fibrils in the compound ascidian Botryllus schlosseri.
No full textIn invertebrates, the recognition of non-self molecules frequently leads to the release of phenoloxidase (PO) by circulating granulocytes, in the form of its precursor, pro-PO, which is quickly activated by soluble serine proteases. This response represents a powerful weapon against potentially pathogenic microorganisms and, in several taxa, independently of their phylogenetic position, the pro-PO activation system is responsible of a massive production of melanin. The latter is supported by the formation of amyloid fibrils as well as other concurrent events, such as ACTH production, NEP overexpression and α-MSH formation.
In the colonial ascidian Botryllus schlosseri, allorecognition between contacting, genetically incompatible colonies, leads to the recruitment of haemocytes in the contact region and their degranulation with the consequent release of PO and the production of melanin which is deposited in the necrotic spots along the colony contacting border
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