Search results for "Ascidia"

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…

Onset of DNA synthesis in experimentally activated ascidian eggs

1994

DNA synthesis was studied autoradiographically in unfertilized ascidian eggs (Ascidia malaca and Ciona intestinalis) that had been artificially activated by a K+-free external medium or a Ca-ionophore. Naked eggs of A. malaca were incubated in K+-free seawater that contained [3H]-thymidine for 30 min, and naked eggs of C. intestinalis were incubated in seawater supplemented with a Ca-ionophore and [3H]-thymidine for 15 min. The observations revealed limited activation in eggs treated with K+-free seawater. Activation consisted of surface modifications and the onset of DNA synthesis. Incorporation of [3H]-thymidine was detected in female nuclei of treated eggs which had not ejected their pol…

Indagini ultrastrutturali sugli effetti di un organometallo dello stagno [tributyltin (IV) chloride] sul processo di neurulazione delle Ascidie.

2006

Un’attenzione particolare è stata rivolta, negli anni più recenti, allo studio degli effetti di un organo metallo contenente stagno, il TBT (IV) chloride, sugli stadi iniziali dello sviluppo embrionale di animali marini. Gli effetti di questo potente inquinante sullo sviluppo e sulla sopravvivenza degli embrioni sono stati proposti come parametri utili per il controllo e il monitoraggio delle acque. Nel presente lavoro sono riportati gli effetti tossici del TBT (IV) chloride sulla neurulazione sull’ascidia Ciona intestinalis, stadio molto importante durante il quale avviene la determinazione del sistema nervoso e la formazione del tubo neurale. L’esposizione degli embrioni allo stadio di ne…

The effect of L-thyroxine on the metamorphosis of Ascidia malaca

1981

Larvae of Ascidia malaca, both before and after hatching, were treated with L-thyroxine solutions. The effect of the thyroid hormone was to induce the onset of metamorphosis and then to cause the rate at which body reorganization occurred to increase. In treated larvae the resorption of the tail occurred only few hours after hatching, and a beating heart appeared form 10 to 15 h earlier than in the control larvae. These results are discussed in the context of a probable relationship between the occurrence of a hormonal metamorphic factor and the button cells of the trunk.

Ciona intestinalis galectin (CiLgals-a and CiLgals-b) genes are differentially expressed in endostyle zones and challenged by LPS

2015

Abstract Immunohistochemical and in situ hybridization assays were performed to answer the question whether the endostyle, that is the initial gastro-intestinal trait of Ciona intestinalis pharynx, is involved in galectin (CiLgals-a and CiLgals-b) production during the pharynx inflammatory response to LPS inoculation. Specific anti-CiLgal-a and anti-CiLgals-b antibodies, and oligonucleotide probes, that mark inflammatory hemocytes inside the pharynx vessels and vessel epithelium as shown by a previous paper, were assayed on endostyle histological sections. For the first time, we show that galectins are produced by endostyle zones, and both CiLgals-a and –b genes are upregulated by LPS. CiLg…

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…

Gene expression and regulation of molecules involved in pharynx inflammatory response induced by LPS in Ciona intestinalis

2017

In the ascidian Ciona intestinalis, the pharynx (hemopoietic organ) connects the external environment to the gastrointestinal system for two main activities, respiration and food collection, potentially exposing the ascidian to high concentrations of pathogenic microorganisms. Recently, evidence in C. intestinalis has indicated that the pharynx is involved in the inflammatory reaction induced by lipopolysaccharide (LPS) injection into the body wall. Immune-related genes such as cytokines, galectins, pro-PO, CAP are expressed in pharynx hemocytes and are up-regulated by the inflammatory agent LPS. Studies of the expression pattern of the immune gene clearly show that in C. intestinalis, as i…

Tributyltin chloride-induced effects on protein tyrosine phosphorylation and on extracellular-signal-regulated kinase (ERK) phosphorilation in Ascidi…

2011

Ascidians represent an intriguing candidate experimental system for studying the effects of environmental stress. We studied TBT effects and probable related pathways were investigated on ascidian embryos by using Western immunoblotting. Among the various signal transduction pathways involved in response to environmental stress, both tyrosine kinase signalling and MAPKs have been played a significant role. To better understand molecular mechanisms after exposure to TBT we studied the two signal transduction pathways above mentioned. Attempting to unravel the molecular effects of TBT-induced on ascidians embryogenesis, TBT treatments carried out in Phallusia mammillata embryos at gastrula st…

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…