1,721,048 research outputs found
Diversity evolution and immune function of fish lectins
No full textFish are equipped with a complex lectin repertoire that, like mammals, are involved
almost all the immune reactions.
Carbohydrate recognition and interactions mediated by lectins have been recognized involved in vertebrate innate immunity, not only
for recognition of potential pathogens, but also acting in the agglutination, immobilization and other functional steps.
Fish are equipped with a complex lectin repertoire that, like mammals, are involved almost all the immune reactions.
Carbohydrate recognition and interactions mediated by lectins have been recognized involved in vertebrate innate immunity, not only for recognition of potential pathogens, but also acting in the agglutination, immobilization and other functional steps.
In fish, C and F types lectins, galectins, rhamnose-binding lectin (RBL) and pentraxin have been identified in both in both cartilaginous and bony fish. In addition, selectins and other genes have been found in the currently available fish genomes.
On the basis of our results on F-type (FBL) and RBL lectins we showed that:
-lectin repertoires in fish are highly diversified and include not only representatives of the lectin families; described in mammals, but also members of lectin families described for the first time in fish species like the FBL and RBL;
-these lectins have been identified in the eggs and embryos but also are present in the serum;
-tissue-specific expression and localization of the diverse lectin repertoires and their molecular partners is consistent with their distinct biological roles in innate and adaptive immunity;
-although some lectins may bind endogenous ligands, others bind sugars on the surface of potential pathogens; in addition to pathogen recognition and opsonization, some lectins display additional effector roles, such as regulation of immune functions
Ciona robusta hemocyte populational dynamics and PO-dependent cytotoxic activity
No full textHemocyte populations from the ascidian Ciona robusta, separated through a Percoll discontinuous density gradient, are further characterized by May-Grünwald-Giemsa staining and a cytochemical reaction for phenoloxidase. Variability in cell density, acidophilic property and phenoloxidase activity suggest multiple hemocyte type populations, cell lineages and morphotypes that may be involved in distinct cellular responses. Therefore, unilocular refractile granulocytes, typical of this ascidian species, enriched in a fraction separated from the hemolymph show in vitro phenoloxidase-dependent cytotoxic activity against mammalian erythrocytes and a tumor cell lineage, in addition the properties listed above indicate relationships with vacuolated signet ring cells. Finally, bromo-deoxyuridine with, diamino-phenylindole fluorescent reaction and May-Grünwald-Giemsa staining show that in the hemolymph there are hyaline amoebocytes and granulocytes with potential proliferating activity. Present findings and reviewed images of previously reported inflammatory hemocytes in the tunic and pharynx allow us to speculate on theoretical outlines of hemocyte differentiation pathways
Evolution, adaptation and immune functions of fish F-type lectins. The novelty of FBL from Trematomus bernacchii (Boulenger, 1902)
Full text linkLectins are a protein family, present in almost all living organisms and involved in different biological pathways, such as immune responses. The Fucose Binding Lectin (FBL), constitute the latest lectin family identified and characterized in fishes. The FBL family is constituted by a large number of proteins exhibiting multiples of the F-type motif, either tandemly arrayed or in mosaic combinations with other domains. In an early step a FBL has been isolated and characterized from serum of the Antarctic fish
Trematomus bernacchii by affinity chromatography on fucose-agarose column. A clear Bacterial agglutinating activity (BA) towards different bacteria strains (Escherichia coli, Kokuria rhizophyla and Bacillus subtilis) and Hemagglutinating activity (HA) toward rabbit erythrocytes was induced from the serum as well from the purified protein and thus confirm its involvement in host pathogen interactions. In SDS-PAGE analysis, the FBL exhibited an apparent molecular weight of 30 kDa. This data is confirmed from the sequence of the F lectin recognised on the T. bernacchii transcriptome. The sequence shows a similar and coherent structure with a supposed Mw 32.16 kDa and an isoelectropoint of 5.21. Furthermore, sequencing the N-terminus confirmed the identity of the sequence runned on SDS PAGE and blotted on PVDF membrane. The HA activity was analyzed at different temperatures and it was maintained also at the physiological living low temperatures of this fish habitat (close to 0 °C). Therefore, in order to identify trends linked to cold adaptation in Antarctic fish, we present our hypothesis on the conformational change determined by the aminoacidic substitutions respect the others fish fucolectins living in warmer water on the light of the general phylogenetic scenario including the new preliminary data on sharks FB
Assessment of morphological and cellular responses after infection with living bacteria in the marine mussel Mytilus galloprovincialis
No full textBacterial strains of Vibrio genus associated with temperate regions are linked to mussels-borne infections. The sedentary nature of marine mussels, Mytilus galloprovincialis, together with their filter feeding combine to ensure that they have the potential for considerable exposure to infective agents.
Bacterial strains of Vibrio genus associated with temperate regions are linked to mussels-borne infections. The sedentary nature of marine mussels, Mytilus galloprovincialis, together with their filter feeding combine to ensure that they have the potential for considerable exposure to infective agents.
The primary mechanism of bivalve internal defense involves hemocytes responsible for cell-mediated immunity through a panel of activities such as phagocytosis, the release of cytotoxic molecules, reactive oxygen intermediates, lysosomal enzymes, PO enzyme and lysozyme.
In this work in vivo infection of M. galloprovincialis with living V. splendidus to collect hemolymph from the posterior adductor muscle 1, 3, 6, 9, 12, 24 and 48 h post-injection was carried out.
Previously we have found that when bacteria were injected into the circulation of the mussel, the number of living intra-hemocyte bacteria dramatically increased already after thirty minutes, suggesting intense phagocytosis, then decreasing until 24 h. The quantification by flow cytometry indicated a variation of proportions of the three cell categories.
In our study, injection of living bacteria resulted in total hemocyte count (THC) higher than normal 24 - 48 h post-injection, suggesting proliferation and/or recruitment of hemocytes which are mainly concentrated in the site of infection.
To compliment this, here histological and immunohistochemical assessment was performed using adductor musclein order to evaluate the morphological features and cellular response spost bacterial infection. The morphological analysis showed changes in tissue organization, with an altered cell volume and recruitment of hemocytes among fibers.
The change of osmotic equilibrium across muscle cell membranes was observed by increased the staining of Na-K ATPase during the entire period of stimulation, and reduced immunopositivity of aquaporin (AQP) 1 h post infection but with an increasing trend in the all experimental steps.
The investigation on cellular turnover showed a tendency to recover a regular tissue structure, as highlighted by an intense immunopositivity of proliferating cell nuclear antigen (PCNA) from 24 h to 48 h post injection, as well as cell surface death receptor (FAS) and the cysteine-aspartic acid protease (CASP3) untilto 72 h post bacterial injection
Cnidarian interaction with microbial communities: From aid to animal’s health to rejection responses
Full text linkThe phylum Cnidaria is an ancient branch in the tree of metazoans. Several species exert a remarkable longevity, suggesting the existence of a developed and consistent defense mechanism of the innate immunity capable to overcome the potential repeated exposure to microbial pathogenic agents. Increasing evidence indicates that the innate immune system in Cnidarians is not only involved in the disruption of harmful microorganisms, but also is crucial in structuring tissue-associated microbial communities that are essential components of the Cnidarian holobiont and useful to the animal’s health for several functions, including metabolism, immune defense, development, and behavior. Sometimes, the shifts in the normal microbiota may be used as “early” bio-indicators of both environmental changes and/or animal disease. Here the Cnidarians relationships with microbial communities and the potential biotechnological applications are summarized and discussed
F-type lectin from serum of the Antarctic teleost fish Trematomus bernacchii (Boulenger, 1902): Purification, structural characterization, and bacterial agglutinating activity
No full textThe increasing availability of sequenced genomes has enabled a deeper understanding of the complexity of fish lectin repertoires involved in early development and immune recognition. The teleost fucose-type lectin (FTL) family includes proteins that preferentially bind fucose and display tandemly arrayed carbohydrate-recognition domains (CRDs) or are found in mosaic combinations with other domains. They function as opsonins, promoting phagocytosis and the clearance of microbial pathogens. The Antarctic fish Trematomus bernacchii is a Perciforme living at extremely low temperatures (-1.68 °C) which is considered a model for studying adaptability to the variability of environmental waters. Here, we isolated a Ca++-independent fucose-binding protein from the serum of T. bernacchii by affinity chromatography with apparent molecular weights of 32 and 30 kDa under reducing and non-reducing conditions, respectively. We have characterized its carbohydrate binding properties, thermal stability and potential ability to recognize bacterial pathogens. In western blot analysis, the protein showed intense cross-reactivity with antibodies specific for a sea bass (Dicentrarchus labrax) fucose-binding lectin. In addition, its molecular and structural aspects, showing that it contains two CRD-FTLs confirmed that T. bernacchii FTL (TbFTL) is a bona fide member of the FTL family, with binding activity at low temperatures and the ability to agglutinate bacteria, thereby suggesting it participates in host-pathogen interactions in low temperature environments
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
