Search results for "ascidian"

Aspects of cell production in mantle tissue of Ciona intestinalis L. (Tunicata, Ascidiacea)

2005

Renewal of cell population is needed in the tunic of ascidians, as the tunic cells are involved in many biological functions. Tunic cells are thought to arrive by migrating across the mantle epithelium into the tunic from the blood lacunae or the mesenchymal space. Electron microscope observations show that the mantle epithelium of Ciona intestinalis shares some proliferative characteristics, releasing cells into the tunic and thus providing an increase renewal of tunical cells in restricted zones of adult animals.

Ultrastructural aspects of naturally occurring wound in the tunic of two ascidians: Ciona intestinalis and Styela plicata (Tunicata).

2015

Efficient wound healing is essential for all animals from insects to mammals. Ciona intestinalis and Styela plicata are solitary ascidians belonging to urochordates, a subphylum that occupies a key phylogenetic position as it includes the closest relative to vertebrates. Urochordate first physical barrier against invaders is the tunic, an extracellular matrix that is constantly exposed to all kinds of insults. Thus, when damage occurs, an innate immune response is triggered to eliminate impaired tissue and potentially pathogenic microbes, and restore tissue functionality. Ultrastructural aspects of the tunic in the wound healing process of two ascidians are described. In the injured areas, …

Functional role of test cells in swimming larvae of Ascidia malaca: ultrastructuraland cytochemical investigations

2004

The functional role played by test cells in larvae of various ascidian species consists in depositing submicroscopic structures known as ornaments and/or proteoglycan substances on the larval test surface. According to the data reported in the literature, the deposition of ornaments together with proteoglycan substances on the larval test would render the latter hydrophilic and thus allow the larva to swim being immersed in water. Ornament deposition on the larval test does not occur in all the ascidian species. Ultrastructural investigations made on larvae belonging to the Cionidae and Ascididae families, for instance, have failed to evidence the presence of ornaments on the test. For thes…

Effects of tributyltin(IV) chloride on fertilization of Styela plicata (Ascidiacea: Tunicata): II. Scanning and transmission electron microscopy stud…

2003

The morphological aspects of Styela plicata fertilization after treatment with tributyltin(IV) chloride are described by means of scanning and transmission electron microscopy investigations. Alterations have been shown both on female and male gametes; spermatozoa, all the egg envelopes and the mitochondria of the egg cortical cytoplasm are modified in relation to incubation time. As a consequence, the damage to gametes blocks sperm-egg interaction and fertilization does not occur. Copyright © 2003 John Wiley & Sons, Ltd.

Effects of tributyltin(IV) chloride on the gametes and fertilization ofAscidia malaca (Ascidiacea: Tunicata)

2003

Ascidia malaca gametes before fertilization incubated in 10-5 or 10-7 M solutions of tributyltin(IV) chloride, TBTCl, for 3 h appear highly damaged under transmission electron microscopy observation. Also, the fertilization process is affected by the compound: the damaged spermatozoa are present in the vitelline coat and the egg does not cleave. An increase of microbodies, structurally similar to peroxisomes, have been detected in the egg peripheral cytoplasm, probably in relation to their role in alleviating damage to some cellular components. The results have shown that the reproduction of ascidians under unfavourable environmental conditions is prevented. Copyright © 2003 John Wiley &amp…

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…

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

2014

Tributyltin affects phagocytic activity of Ciona intestinalis hemocytes

1995

Organotin compounds have been used in marine anti-fouling paints as biocides. Because tunicates are vulnerable to these compounds in their natural habitats, we used Ciona intestinalis to establish an assay for phagocytosis in vitro of yeast by hemocytes after exposure to different concentrations (0.0015, 0.015, 0.15 and 1.5 microM) of four organotin compounds: tributyltin (TBT), triphenyltin (TPT), dibutyltin (DBT) and diphenyltin (DPT). To evaluate the phagocytic activity, we used a method based on fluorescence excitation of yeast pre-treated with eosin-Y. The percentage of phagocytosis decreased from 45.1 +/- 3.49 to 22.4 +/- 5.14 at 1.5 microM of TBT (P0.001); it was significantly reduce…

Inflammatory responses of the ascidian Ciona intestinalis.

2008

«Correlation between granulocytes and tunic cuticle of Ciona intestinalis (Tunicata, Ascidiacea) as evaluated by microscopy»

2012

The tunic is a peculiar integumentary tissue covering the epidermis of ascidians and other tunicates. It is an extracellular matrix whose outermost surface is revealed to be a continuos layer called tunic cuticle, composed of electron dense fibrous materials. Mechanisms occurring during the growth of the animal after metamorphosis, must assure the maintenance of the thin tunic cuticle density and integrity as it represents the primary body surface barrier preventing the mechanical and microbial assaults. Investigations by optical and electron microscopy on tunic samples from young Ciona intestinalis, allowed us to study morphological relationship between the tunic cuticle architecture and g…