Search results for "tunicate"
showing 10 items of 32 documents
Cloning of Sponge (Geodia cydonium) and Tunicate (Botryllus schlosseri) Proteasome Subunit Epsilon (PRCE): Implications about the Vertebrate MHC-Enco…
1996
Proteasomes are large protein complexes that play a major role in selective degradation of intracellular proteins. Eukaryotes feature seven different alpha and beta subunits. Two of the vertebrate housekeeping beta-subunits have MHC-encoded homologues that can substitute for the housekeeping counterparts upon interferon-gamma induction. In the present study we report the cloning of invertebrate beta-subunit proteasome epsilon (PRCE), from the marine sponge Geodia cydonium and from the colonial tunicate Botryllus schlosseri. Sequence comparisons revealed that the sponge and tunicate proteins are strikingly similar to vertebrate and yeast PRCEs and their MHC-linked counterparts the PRCCs (als…
A tunicate (Botryllus schlosseri) cDNA reveals similarity to vertebrate antigen receptors
1996
Prophenoloxidase activating system in tunicate hemolymph
1996
The activation sequence and related factors of the prophenoloxidase activating system in crustaceans was compared with the equivalent system in tunicates. Both solitary and colonial ascidians present in their hemolymph a copper-dependent phenoloxidase activity that may be inhibited by tropolone and phenylthiourea. Carbohydrates are able, to various extents, to trigger proPO system which requires serine protease cleavage for activation to phenoloxidase (PO). In some ascidians, hemocytes called ≪morula cells≫ show PO activity, while in Ciona intestinalis the ≪univacuolar refractile granulocytes≫ are positive after cytochemical staining with L-dopa. The relationships between proPO system and d…
Tunicate immunocytes can be cytotoxic toward foreign cells
2008
Effetti antiproliferativi degli estratti di emociti dell'ascidia Styela plicata ( Tunicata)
2009
Cellular components and tunic architecture of the solitary ascidian Styela canopus (Stolidobranchiata, Styelidae).
1998
Abstract Cell distribution and tunic morphology in the ascidian Styela canopus were examined by electron microscopy. The observations showed that the outer covering is composed of a thin sinuous cuticle with several protrusions and a deep layer of ground substance. The fibrous component and its arrangement in the tunic were demonstrated: elementary fibrils exhibit a ‘microtubular’ structure and an elliptical cross-sectional shape. Four types of cells were described: clear vesicular tunic granulocytes, tunic microgranulocytes, unilocular tunic granulocytes, and globular tunic granulocytes. Morphofunctional aspects of the tunic tissue and certain phylogenetic relationships are discussed.
Circulating hemocytes and pharyngeal explants of Styela clava release hemagglutinin in vitro
1997
Tunicate blood cells are a mixed population, thus experiments that assay their immunodefense responses, such as release of hemagglutinins, were done to isolate different functional hemocytic types. Two sources of hemocytes from Styela clava were used, the hemolymph and the pharynx (the hemopoietic organ). Hemolymph centrifuged through a discontinuous Percoll gradient yielded four distinct bands of hemocytes. After incubation at 15°C, circulating hemocytes and those from pharyngeal cultures released hemagglutinin after 2 and 30 days. Highest titers were found in B1 (hyaline and compartment cells), B3 (hyaline cells and eosinophil granulocytes), and B4 (hyaline cells and debris). Hemagglutina…
Inflammatory hemocytes in Ciona intestinalis innate immune response
2009
In the present paper an attempt is carried out to revise Ciona intestinalis inflammatory hemocytes according to their morphology as formerly observed by light and electron microscopy, and taking in account recent reports on innate immunity gene expression. We also examine hemocyte morphofunctional aspects as derived from previous papers that refer to the tunic and body wall inflammatory responses challenged by corpusculate or soluble agents. LPS inoculation into the body wall or treating hemocytes in vitro with LPS have also been taken in account. LPS inoculation stimulated the expression of CiTNF alpha, CiFACIT- alpha chain collagen, CiC3a, CiCD94 and enhanced phenoloxidase activity. These…
The identification and localization of two intermediate filament proteins in the tunic of Styela plicata (Tunicata, Styelidae).
2009
The intermediate filament (IF) proteins Styela C and Styela D from the tunicate Styela (Urochordata) are co-expressed in all epidermal cells and they are thought to behave as type I and type II keratins. These two IF proteins, Styela C and Styela D, were identified in immunoblots of proteins isolated from the tunic of Styela plicata. The occurrence and distribution of these proteins within the tunic of this ascidian was examined by means of immunofluorescence and immunoperoxidase techniques, using anti-Styela C and anti-Styela D antibodies. In addition, immuno-electron microscopy of the tunic showed that the two proteins are located in the cuticle layer and in the tunic matrix. These result…