Search results for "ASCIDIANS"

Ultrastructural aspects of the tunic wound repair in Styela plicata and Ciona intestinalis (Tunicata)

2014

Characterization and transcription studies of a phytochelatin synthase gene from the solitary tunicate Ciona intestinalis exposed to cadmium.

2014

The major thiol-containing molecules involved in controlling the level of intracellular ROS in eukaryotes, acting as a nonenzymatic detoxification system, are metallothioneins (MTs), glutathione (GSH) and phytochelatins (PCs). Both MTs and GSH are well-known in the animal kingdom. PC was considered a prerogative of the plant kingdom but, in 2001, a phytochelatin synthase (PCS) gene was described in the nematode Caenorhabditis elegans; additional genes encoding this enzyme were later described in the earthworm Eisenia fetida and in the parasitic nematode Schistosoma mansoni but scanty data are available, up to now, for Deuterostomes. Here, we describe the molecular characteristics and transc…

The Expression of an Immune-Related Phenoloxidase Gene is Modulated in Ciona Intestinalis Ovary, Test Cells, Embryos and Larva

2015

Two distinct Ciona intestinalis phenoloxidases (CinPO1, 2) had previously been cloned and sequenced. The CinPO2 is involved in innate immunity and is expressed by inflammatory hemocytes that populate the tunic and pharynx vessels as a response to LPS inoculation. In situ hybridization and immunohistochemistry assays on histological section, showed that the expression of this gene and the produced protein are shared with oogenesis, embryogenesis and larval morphogenesis. Intriguingly, upregulation of gene transcription was found in the test cell layer that envelopes the ovary follicle, ovulated egg, and gastrula, as well as it was modulated in the zygotic nucleus of outer balstomers of 32-ce…

TRIBUTYLTIN-INDUCED EFFECTS ON MAPK SIGNALING IN ASCIDIAN EMBRYOS

2008

Among the class of organotin compounds, the most well known is tributyltin (TBT). Organotin have many applications, which include use in PVC, as catalyst in chemical reactions, agricultural pesticides and antifungal treatments for textile polymers. In particular TBT is used in marine antifoulant paints to prevent the growth of organisms such as barnacles on the hull of ships. Extensive use in antifouling paints led to the widespread distribution of TBT and its breakdown products in the global marine, sediment and biota. High levels of TBT in the waters were found to have impaired reproduction, by inhibiting embryogenesis and larval development in a variety of marine organisms. Symptoms of t…

The Inflammatory Response of Urochordata: The Basic Process of the Ascidians’ Innate Immunity

2018

Ascidians form a widespread marine invertebrate group and are heterogeneous in terms of the taxonomic groups’ evolutionary lineages. The ascidian genomes lack significant homologies for rearranging genes of the vertebrate adoptive immunity. Genome analysis, gene sequencing, and transcriptional profiling have allowed us to disclose upregulation of innate immunity genes and cell labeling with riboprobes and antibodies has identified hemocyte types in tunic and pharynx inflammatory responses. Lymphocyte-like cells are stem cells and their immunocompetence has been proposed. Granulocyte types (compartment/morula cells) and hemocytes with large granules/vacuoles (compartment/morula cells) are ma…

COMPARATIVE ULTRASTRUCTURAL INVESTIGATION ON THE ADHESIVE PAPILLAE OF THE SWIMMING LARVAE OF THREE ASCIDIAE SPECIES

2008

Ascidian swimming larvae bear three peculiar organs of ectodermic origin, named “palps” or adhesive papillae, located in the anterior region of cephalenteron. Term “adhesive” is correlated to one of the function of these structure based on secretion of an adhesive substance which enables swimming larvae to adhere to a substratum. Recently a sensory function has also been described in some Phlebobranchia papillae with a simple morpho-functional organization. There are few ultrastructural investigations in literature, sometimes disputed, able to make clear papillae cells functions. To clarify this problem, a comparative investigation has been carried out, just in this work, about ultrastructu…

Influence of cadmium on the morphology and functionality of haemocytes in the compound ascidian Botryllus schlosseri

2013

In order to get insights into the effects of cadmium (Cd) on cell morphology and functions, we exposed haemocytes of the colonial ascidian Botryllus schlosseri to sub-lethal concentrations of CdCl(2). Results indicate that Cd hampers haemocyte spreading and phagocytosis in a dose-dependent way, through the alteration of the actin cytoskeleton. In addition, the metal decreases the stability of the internal membranes, as revealed by the Neutral Red assay. The fraction of cells showing positivity for the lysosomal enzyme acid phosphatase is also reduced in the presence of Cd, whereas the number of cells responsive to the Annexin-V assay and showing chromatin condensation increases, suggesting …

CiC3-1a-Mediated Chemotaxis in the Deuterostome Invertebrate Ciona intestinalis (Urochordata)

2003

Abstract Deuterostome invertebrates possess complement genes, and in limited instances complement-mediated functions have been reported in these organisms. However, the organization of the complement pathway(s), as well as the functions exerted by the cloned gene products, are largely unknown. To address the issue of the presence of an inflammatory pathway in ascidians, we expressed in Escherichia coli the fragment of Ciona intestinalis C3-1 corresponding to mammalian complement C3a (rCiC3-1a) and assessed its chemotactic activity on C. intestinalis hemocytes. We found that the migration of C. intestinalis hemocytes toward rCiC3-1a was dose dependent, peaking at 500 nM, and was specific for…

The ascidian prophenoloxidase activating system

2009

Phenoloxidases/tyrosinases initiate melanin synthesis in almost all organisms, and are involved in different biological activities such as the colour change of human hair and the browning or blackening of fruit skin etc. In many invertebrates, defence reactions are linked to phenoloxidase activity and/or melanization. Contacts with foreign molecules are able to trigger the prophenoloxidase (proPO) system that requires serine protease cleavage for activating the zymogen to phenoloxidase (PO). It is generally accepted that the proPO system is fully expressed in arthropods, and, recently, progress in the regulation of crustacean and insect proPO activation steps have been achieved. After cells…

The conservation and diversity of ascidian cells and molecules involved in the inflammatory reaction: The Ciona robusta model

2021

Ascidians are marine invertebrate chordates belonging to the earliest branch (Tunicata) in the chordate phylum, therefore, they are of interest for studying the evolution of immune systems. Due to the known genome, the non-colonial Ciona robusta, previously considered to be C. intestinalis type A, is a model species for the study of inflammatory response. The internal defense of ascidians mainly relies on hemocytes circulating in the hemolymph and pharynx. Hemocytes can be in vivo challenged by LPS injection and various granulocyte and vacuolated cell populations differentiated to produce and release inflammatory factors. Molecular biology and gene expression studies revealed complex defens…