Effects of cadmium exposure on sea urchin development assessed by SSH and RT-qPCR: metallothionein genes and their differential induction.

In order to study the defense strategies activated by Paracentrotus lividus embryos in response to sub-lethal doses of CdCl2, we compared the induced transcripts to that of control embryos by suppression subtractive hybridization technique. We isolated five metallothionein (MT) cDNAs and other genes related to detoxification, to signaling pathway components, to oxidative, reductive and conjugative biotransformation, to RNA maturation and protein synthesis. RT-qPCR analysis revealed that two of the five P.

Functional role of test cells in swimming larvae of Ascidia malaca: ultrastructural and cytochemical investigations.

The functional role played by test cells in larvae of various ascidian species consists in depositing sub-microscopic 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.

Early stages of test formation in larva of Ascidia malaca (Tunicata, Ascidiacea): ultrastructural and cytochemical investigations.

The swimming larvae of ascidians are entirely covered by a hyalin coat called tunic, or test. This covering consists of two cuticular layers, C1 and C2, which surround an inner compartment composed of an amorphous hyalin matrix with numerous fibrils dispersed inside. Data from the literature agree on the key role played by the cells of the larval ectodermic layer in the synthesis and secretion of larval test components.

Morphological and demographic associations of biliary symptoms in subjects with gallstones: findings from a population-based survey in Rosario, Argentina.

Background: Gallstone disease is a frequently encountered disorder in subjects living in Rosario. The reasons for the presence or absence of symptoms are unknown.

Aims: To determine associations between biliary symptoms and ultrasonographic features of gallbladder and gallstones.

Ultrastructural and cytochemical investigations on the formation of chorion in oocyte of Ascidia malaca.

In the present work are reported investigations on the formation and chemical nature of the chorion of Ascidia malaca oocytes. The ultrastructural observations have shown that both follicle cells and test cells play a key role on chorion formation. At the beginning of vitellogenesis (stage I), chorion is formed by a single fibrogranular layer.