1,721,050 research outputs found
BsTLR1: A new member of the TLR family of recognition proteins from the colonial ascidian Botryllus schlosseri
Get PDFToll-like receptors (TLRs) represent a well-known family of conserved pattern recognition receptors the importance of which, in non-self recognition, was demonstrated in both vertebrates and invertebrates. Tunicates represent the vertebrate sister group and, as invertebrates, they rely only on innate immunity for their defence. As regards TLRs, two transcripts have been described and characterised in the solitary species Ciona intestinalis, referred to as CiTLR1 and CiTLR2. Using the Ciona TLR nucleotide sequences, we mined our available transcriptome of the colonial ascidian Botryllus schlosseri looking for similar sequences. We were able to identify a sequence, with similarity to CiTLR2 and, through in silico transduction and subsequent sequence analysis, we studied the domain content of the putative protein. The sequence, called BsTLR1, has a TIR and a transmembrane domain, four LLR and two LRR-CT domains. It is actively transcribed by both phagocytes and morula cells, the two circulating immunocyte types. In addition, we analysed bstlr1 transcription in vivo and in vitro, in different phases of the Botryllus blastogenetic cycle and under various experimental conditions. Our data show that there is a change in gene expression and mRNA location, according to the blastogenetic phase. Furthermore, we used a commercial antibody raised against the ectodomain of hTLR5 to study the possible functional role of Botryllus TLR(s). We observed that anti-hTLR5 significantly decreased in vitro phagocytosis and morula cell degranulation, two typical responses to the recognition of nonself. Collectively, our data add new information on the mechanisms of nonself recognition in a colonial ascidian
Advances in Aquatic Invertebrate Stem Cell Research. From Basic Research to Innovative Applications
Get PDFAquatic invertebrates represent the largest biodiversity and the widest phylogenetic radiation on Earth, with more than 2 million known species. Up until a few years ago, their use as Model organisms in biological research was limited by the paucity of omics data. Recently, the situation has rapidly changed and is still changing. Today, the genomes and various transcriptomes of many aquatic invertebrate species, as well as many recombinant proteins of invertebrate origin, are available. New technologies have revolutionised the available toolbox of research methodologies. This explains the rising interest of researchers in the use of aquatic invertebrates as reliable model organisms. In contrast to the prevalence of diverse oligopotent and unipotent stem cells in vertebrates, aquatic invertebrates (especially non-ecdysozoan invertebrates) exhibit multiple adult cell types with stem cell attributes characterised by multipotency and pluripotency; furthermore, these give rise to cell lineages characteristic of more than a single germ layer, sometimes with somatic and germ line potentials. In addition, unlike vertebrates, aquatic invertebrate adult stem cells are disseminated and widespread inside the animal body, are not associated with a regulatory microenvironment (niche), and do participate in ageing and regeneration phenomena. These properties can help us to better understand the processes and phenomena in mammalian stem cell biology, such as natural chimerism and cancer, ageing and senescence, immunity, and autoimmune responses, which are all difficult to explain or understand in the human context
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Get PDFAscidians are invertebrate chordates and may reveal parallels to vertebrate traits including cellular immunity, tissue rejection, and self-renewal, all functions executed by ascidian blood cells. Understanding their individual properties, functional plasticity, and lineage resemblances among ascidian species is, however, limited by a lack of cytochemical and molecular markers. We performed a lectin-based glycan profiling of haemocytes in three selected ascidian species to compare different blood cell populations and mirror their relatedness. We found differing repertoires of species-specific glycans for blood cells believed to be homologous in their function. Within species, characteristic glycans or glycan combinations mark haemocyte types and support their hematopoietic relatedness or distinguish maturation stages. Strikingly, Ciona and Phallusia haemoblasts have few carbohydrate decorations and drastically differ from differentiated cells,
likewise phagocytes from cytotoxic cells, as compared with Botryllus, where a complex role of haemocytes in asexual self-renewal and allorecognition may involve carbohydrates. Cytotoxic cells generally carry most decorations. Within cell types, specific carbohydrates reside on the cell surface including amoeboid extensions, while others are within granules possibly marking molecules important in cytotoxicity and crosslinking. Taken together, these carbohydrate biosensors should further the molecular and functional characterisation of the outstanding
properties of the different haemocytes in genetically accessible ascidian species
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Get PDFAdult stem cells (ASCs) of aquatic invertebrates are involved in important biological processes such as regeneration and asexual reproduction. Unlike vertebrates, they share pluripotency and even totipotency and do not reside in permanent niches. Aquatic invertebrates represent the widest phylogenetic animal radiation on Earth but, up to now, limited research data are available on their ASCs. Although less studied than their vertebrate counterparts, aquatic invertebrate ASCs express orthologues of many vertebrate genes usually associated with stemness. With this review, we aim at providing a data base for current and future studies on ASC properties through a comprehensive literature analysis of intra- and inter-phylum comparisons for gene expressions and their functions in aquatic invertebrate ASCs. We concentrate on major gene families where sufficient data are available; gaps in our results will be filled by future studies on ASCs of aquatic invertebrates.Europäische Kommission 847681Version of recor
Ascidian cytotoxic cells: from zero to hero
Get PDFUntil four decades ago, ascidian cytotoxic cells were considered too differentiated to exert any important function in the biology of the organisms. Their unique accepted roles were related to tunic synthesis and storing nutrients (trophocytes) useful to support other processes. Things changed starting from the beginning of the eighties of the last century when it progressively became clear that they are directly involved in inflammatory reactions. In the last decade, it was ascertained that these cells, once neglected, deeply influence ascidian biology, as they are the main source of cytokines modulating the activity of immunocytes, and of the majority of the complement components that assure correct immune responses. Moreover, they can also produce and release antimicrobial peptides that protect the organism from infections
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