1,721,177 research outputs found
Univacuolar refractile hemocytes from the tunicate Ciona intestinalis are cytotoxic for mammalian erythrocytes in vitro
No full textA discontinuous, Percoll density gradient was used to separate hemocyte populations from the hemolymph of Ciona intestinalis. Hemocytes from each band were examined for their frequency, morphology, and cytotoxic activity against rabbit and sheep erythrocytes; results were expressed as a percentage of hemolysis. Statistical analysis revealed that only the 'univacuolar' granulocytes from Band 5, which contain a vacuole of refractile material, were cytotoxic. Cytotoxic activity was inhibited by sphingomyelin. For the first time in tunicates, lytic activity against erythrocytes was assessed by an assay based on plaque-forming cells. Plaques of lysis were revealed against rabbit erythrocytes but not against sheep erythrocytes
Population abundance, structure and movements of the European pond turtle, Emys orbicularis (Linnaeus 1758) based on capture-recapture data in a Venice Lagoon wetland area, Italy
No full textA freshwater turtle monitoring programme along the inland margins of the Venice lagoon was initiated in 2019 in collaboration with the World Wild Fund for Nature (WWF-Italy). From a total of 336 European pond turtles (Emys orbicularis) captured and marked, 97 freshwater turtles were recaptured at least once (28.9% return rate) providing important information on population size, structure and movements of mature individuals within the study area. The population size was estimated with capture-recapture method (Capture-Mark-Recapture-CMR) at 1009.4 ± 365.2 pond turtles, with a mean density of 252.3 ± 91.3 ind./ha. The analysis of the movements showed that the average distance covered intra-water bodies was: 146.79 ± 117.08 m for females and 125.43 ± 112.34 m for males. A total of 17 E. orbicularis (eight females and nine males) out of 97 turtles changed the water body during the study period from April to early September. Only a female freshwater turtle migrated in all three study sites, being recaptured 1502.32 m from the tagging site. The percentage of captures was significantly higher in two canals than in the brackish lake habitat. Further research should address spatial distribution at a finer scale to evaluate the preferential habitat for threatened E. orbicularis populations in a transitional water system as the lagoon
Effects of an entomopathogen nematode on the antimicrobial response of Red Palm Weevil (Rhynchophorus ferrugineus)
No full textProphenoloxidase activating system in tunicate hemolymph
No full textThe activation sequence and related factors of the prophenoloxidase activating system in crustaceans was compared with the equivalent system in tunicates. Both solitary and colonial ascidians present in their hemolymph a copper-dependent phenoloxidase activity that may be inhibited by tropolone and phenylthiourea. Carbohydrates are able, to various extents, to trigger proPO system which requires serine protease cleavage for activation to phenoloxidase (PO). In some ascidians, hemocytes called ≪morula cells≫ show PO activity, while in Ciona intestinalis the ≪univacuolar refractile granulocytes≫ are positive after cytochemical staining with L-dopa. The relationships between proPO system and defence reactions (opsonic, cytotoxic) of ascidians are discussed. © 1996 Taylor & Francis Group, LLC
Bright spots in the darkness of cancer: A review of starfishes-derived compounds and their anti-tumor action
Full text linkThe fight against cancer represents a great challenge for researchers and, for this reason, the search for new promising drugs to improve cancer treatments has become inevitable. Oceans, due to their wide diversity of marine species and environmental conditions have proven to be precious sources of potential natural drugs with active properties. As an example, in this context several studies performed on sponges, tunicates, mollusks, and soft corals have brought evidence of the interesting biological activities of the molecules derived from these species. Also, echinoderms constitute an important phylum, whose members produce a huge number of compounds with diverse biological activities. In particular, this review is the first attempt to summarize the knowledge about starfishes and their secondary metabolites that exhibited a significant anticancer effect against different human tumor cell lines. For each species of starfish, the extracted molecules, their effects, and mechanisms of action are described
Evolutionary and transcriptional analyses of a pentraxin-like component family involved in the LPS inflammatory response of Ciona robusta
No full textPentraxins (PTXs) are a superfamily of conserved proteins which are components of the humoral arm of innate immunity. They are considered to be functional ancestors of antibodies and are classified into short and long types. In this study, we show that a pentraxin-like component (Ptx-like) with a C-terminal PTX domain, highly homologous to the short PTX of H. sapiens CRP, and a long N-terminal domain typical of long PTXs, is involved in the inflammatory response of Ciona robusta under LPS exposure in vivo. Analyses of protein domains as well as 3D modelling and phylogenetic tree supported the close relationship of Ptx-like with mammalian CRP, suggesting that C. robusta Ptx-like shares a common ancestor in the chordate lineages. qRT-PCR analysis showed that Ptx-like was transcriptionally upregulated during the inflammatory process induced by LPS inoculation and that it is involved in the initial phase as well as the secondary phase of the inflammatory response in which matrix remodelling and the achievement of homeostasis occur. In situ hybridisation assays revealed that gene transcription was upregulated in the pharynx post-LPS challenge in vivo, and that Ptx-like was expressed by clusters of haemocytes, mainly granulocytes, inside the pharynx vessels. We also found transcript-expressing granulocytes flowing in the musculature and in the lacunae of the circulatory system. These data supported that Ptx-like is a potential molecule of the acute-phase response in C. robusta immune defence systems against bacterial infection
Phenoloxidase characterization in vacuolar hemocytes from the solitary ascidian Styela plicata
No full textPhenoloxidase (PO) activity was shown in lysates of Styela plicata hemocytes assayed spectrophotometrically by means of L-Dopa oxidation without divalent cations. Trypsin and chymotrypsin pretreatment and preincubation with microbial lipopolysaccharides significantly activated PO, whereas laminarin or zymosan were ineffective. Soybean trypsin inhibitor, tropolone, and phenylthiourea, but not benzamidine, were inhibitors. Finally, hemocytes were separated by a discontinuous Percoll density gradient to determine which cells were active. PO activity was demonstrated, by both biochemical and cytochemical assays, in the separated fraction enriched mainly with the globular granulocytes called morula cells. © 1995 by Academic Press, Inc
Stress and immune response to bacterial LPS in the sea urchin Paracentrous lividus (Lamarck, 1816)
No full textThe immune system of the sea urchin species Paracentrotus lividus is highly complex and, as yet, poorly understood. P. lividus coelomocytes mediate immune response through phagocytosis and encapsulation of non-self particles, in addition to the production of antimicrobial molecules. Despite this understanding, details of exactly how these processes occur and the mechanisms which drive them are still in need of clarification. In this study, we show how the bacterial lipopolysaccharides (LPS) is able to induce a stress response which increases the levels of the heat shock proteins HSP70 and HSP90 only a few hours after treatment. This study also shows that LPS treatment increases the expression of the beta-thymosin-derivated protein paracentrin, the precursor of antimicrobial peptides
Comparative evaluation of coelomocytes in Paracentrotus sea urchins: Description of new cell types and insights on spherulocyte maturation and sea urchin physiology
No full textSea urchins are the best-known models in echinoderm immunology and only four coelomocytes - i.e. phagocytes, vibratile cells, and red and colorless spherulocytes - have traditionally been observed in these animals. However, recent studies have demonstrated that this number could be underestimated, which consequently may hinder a better understanding of sea urchin physiology. Here, we investigated the cells of one of the most known sea urchin genera in the world: the genus Paracentrotus. This genus comprises two species with distinct geographic distributions, thus providing an excellent scenario for comparative analyses. In this context, through an inte-grative approach consisting of living cells, cytological preparations, and scanning electron microscopy (SEM), we analyzed morphological, morphometric, and cytochemical characteristics of the coelomocytes of Paracentrotus lividus (Lamarck, 1816) and Paracentrotus gaimardi (Blainville, 1825). Seven different coelomic subpopulations were found in these species, including the traditional types and the granular spherulocyte, crystal cell, and progenitor cell. For all spherulocyte subpopulations, a set of morphologically similar cells were observed in both cytological and SEM preparations. Based on morphology, morphometry, and cytochemistry, we observed that these morphotypes could be organized in a sequence, which we interpreted as a maturation process. Then, we raise one hypothesis that explains how spherulocytes mature. Lastly, taking into account the all results achieved by this study, we discuss (1) how the morphological, morphometric, and cytochemical characteristics observed in Paracentrotus coelomocytes may be used to identify the coelomocytes of other sea urchins; (2) the physiological implications of our findings. Considering that P. lividus is one of the most studied sea urchins in the world, the new findings obtained here may shed new light on traditional aspects of sea urchin immunology (e.g. coelo-mocytes function), as well as stimulate research on new aspects of Echinoidea and even in Echinodermata immunology
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