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The hemocytes of Polyandrocarpa misakiensis, with particular reference to immunocytes.
No full textPolyandrocarpa misakiensis is a polystyelid compound ascidian, common along the coasts of the temperate regions of Japan, which can reproduce asexually through continuous budding from parental zooids. The hemolymph of this species contains the following main cell-types: undifferentiated cells, phagocytes, including both hyaline amebocytes and macrophage-like cells, microgranular leukocytes, macrogranular leukocytes, morula cells and pigment cells.
Immunocytes are represented by phagocytes and morula cells. Phagocytes are capable of constitutive macropinocytosis, can release lectins and ingest macrogranular leukocytes in order to provide nutrients required for growth of developing buds. Like other compound ascidians, Polyandrocarpa morula cells (MCs) represent one of the most abundant circulating hemocyte types. They share the presence of DOPA-oxidase activity inside their vacuoles, ascribable to the presence of phenoloxidase, a key enzyme in invertebrate immune responses, which is released in extracellular compartment upon the recognition of foreign cells or molecules thus inducing a cytotoxic response. This enzyme can be considered, in all respects, a differentiation marker of morula cells as no other cell types show similar enzyme activity. Recently, we were able to clone a cDNA sequence of 1985 bp, representing most of the PO transcript. It shows homology with arthropod hemocyanins and, through in situ hybridization, we demonstrated that MC are the only cells expressing the corresponding mRNA
The hemocytes of Polyandrocarpa misakiensis: morphology and immune-related activities.
Get PDFA preliminary study of the hemocytes of developing buds of the compound ascidian Polyandrocarpa misakiensis was carried out at the light microscope level for a better understanding of their biological role. Similarly to other ascidians, P. misakiensis immunocytes are represented by phagocytes and morula cells. Phagocytes include hyaline amoebocytes and round, giant phagocytes, the former the probable precursors of the latter. Hyaline amoebocytes showed high macropinocytotic activity in the presence of bacteria, whereas yeast cells were ingested by phagocytosis. Morula cells contain the enzyme phenoloxidase inside their vacuoles, probably stored as pro-enzyme, which is released upon the recognition of non-self. Together with macrogranular leukocytes, morula cells were the most abundant hemocyte-types which stresses the importance of these cells in Polyandrocarpa biology. Macrogranular leukocytes are frequently found inside the vacuoles of phagocytes and were recognized by a polyclonal antibody raised against an opsonin purified from the colonial ascidian Botryllus schlosseri, which suggests that a similar lectin can be involved in the interaction between these cells and phagocytes
Nanos homologue expression in haemocytes of two botryllid ascidians (Botryllus primigenus and Botryllus schlosseri)
No full textNanos and nanos-related genes encode RNA-binding proteins and are expressed by stem cells of many metazoans. In the Japanese colonial ascidian Botryllus primigenus, a nanos homologue of 1.3 kb, Bpnos, has been recently identified (Sunanaga et al., 2008), containing two nanos-like CCHC zinc finger motifs. The gene in expressed in germ stem cells, immature and mature male germ cells, as well as in a fraction of circulating haemocytes. Using an anti-Bpnos monoclonal antibody, we confirmed that haemoblasts, i.e., circulating undifferentiated cells, are the only haemocytes recognised by the antibody in both B. primigenus and the Mediterranean species Botryllus schlosseri. In both species, the frequency of haemoblasts reaches the maximum value just after the take-over phase, when the generation change occurs and gradually decreases during the rest of the cycle. The number of circulating haemoblasts is much higher in the Japanese than in the Mediterranean species and this can be related to the occurrence of spontaneous vascular budding in B. primigenus. We also identified a nanos-related gene in B. schlosseri, sharing the nanos domain with two CCHC motifs, which we propose to call Bsnos. We are now trying to get the full cDNA sequence and the deduced amino acid sequence in order to get probes for Bsnos expression studies
Nanos homologue expression in haemocytes of two botryllid ascidians (Botryllus primigenus and Botryllus schlosseri)
No full textNanos and nanos-related genes encode RNA-binding proteins and are expressed by stem cells of many metazoans. In the Japanese colonial ascidian Botryllus primigenus, a nanos homologue of 1.3 kb, Bpnos, has been recently identified (Sunanaga et al., 2008), containing two nanos-like CCHC zinc finger motifs. The gene in expressed in germ stem cells, immature and mature male germ cells, as well as in a fraction of circulating haemocytes. Using an anti-Bpnos monoclonal antibody, we confirmed that haemoblasts, i.e., circulating undifferentiated cells, are the only haemocytes recognised by the antibody in both B. primigenus and the Mediterranean species Botryllus schlosseri. In both species, the frequency of haemoblasts reaches the maximum value just after the take-over phase, when the generation change occurs and gradually decreases during the rest of the cycle. The number of circulating haemoblasts is much higher in the Japanese than in the Mediterranean species and this can be related to the occurrence of spontaneous vascular budding in B. primigenus. We also identified a nanos-related gene in B. schlosseri, sharing the nanos domain with two CCHC motifs, which we propose to call Bsnos. We are now trying to get the full cDNA sequence and the deduced amino acid sequence in order to get probes for Bsnos expression studies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
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