R. Carmona

Biology, Conservation and Sustainable Development of Sturgeons

Taxonomy and Biogeography.- The Regression of Sturgeons in Southern Europe.- Analysis of Mitochondrial and Nuclear DNA Markers in Old Museum Sturgeons Yield Insights About the Species Existing in Western Europe: A. sturio, A. naccarii and A. oxyrinchus.- Morphological and Morphometric Characters in Sturgeon Taxonomy and Phylogeny.- Molecular Markers and the Study of Phylogeny and Genetic Diversity in North American Sturgeons and Paddlefish.- Forensic Strategies Used for DNA Extraction of Ancient and Degraded Museum Sturgeon Specimens.- Mechanisms of Polyploid Evolution in Fish: Polyploidy in Sturgeons.- Biology and Aquaculture.- Histological, Histochemical and Ultrastructural Changes in the Digestive Tract of Sturgeon Acipenser naccarii During Early Ontogeny.- The Developmental Anatomy of the Heart of the Sturgeon Acipenser naccarii.- Observations on the Brain Development of the Sturgeon Acipenser naccarii.- Hormonal Induction of Ovulation In Vitro in Sturgeon Fishes.- Dispermic Androgenesis as a Method for Recovery of Endangered Sturgeon Species.- Influence of Temperature on the Sterlet (Acipenser ruthenus L.) Ovarian Follicles State.- On Nutrition and Feeding Studies as the Basis for the Culture of Different Sturgeon Species.- Recovery and Conservation.- Restoration of Adriatic Sturgeon (Acipenser naccarii) in Italy: Situation and Perspectives.- Acipenser sturio Recovery Research Actions in France.- Conservation of the Sturgeon Fish in Lower Volga.- Experience of Conservation of Acipenser naccarii in the Ticino River Park (Northern Italy).- Identification of Sturgeon Caviar Using DNA Markers.- International Trade in Caviar and Business Perspectives in Russia.- The Ecological Problems of Introduction and Reintroduction of Sturgeons.- Hydrological and Production Characteristics of the Main Basins for Reproduction and Fattening of Sturgeons.- Towards the Definition of Optimal Size-Weight Standards of Hatchery-Reared Sturgeon Fry for Restoration.- Acceptability and Prerequisites for the Successful Introduction of Sturgeon Species.- Prerequisites for the Restoration of the European Atlantic Sturgeon, Acipenser sturio and the Baltic Sturgeon (A. oxyrinchus x A. sturio) in Germany.- Sturgeon Recovery Plan in the Rhone River (France): Preliminary Results on Species Determination and Habitat Suitability.- Main Steps and Proposals for a Recovery Plan of Sturgeon in the Guadalquivir River (Spain).

Study of the Olfactory Epithelium in the Developing Sturgeon. Characterization of the Crypt Cells

In acipenserids, crypt cells (CCs) have only been observed in juvenile specimens, and it has not been clarified whether they differentiate along with olfactory receptor neurons (ORNs) during the lecithotrophic stage or during later development stages. Furthermore, no detailed optical microscopy (OM) or electron microscopy study on the development of CCs has been published to date. In the present study, we used OM and electron microscopy to follow the development of CCs in Acipenser naccarii from hatching to the establishment of exogenous feeding. Based on these observations, we can affirm that CCs are present from the first few posthatching (PH) days. CCs appear with their nucleus close to the basal lamina of the epithelium and enveloped by supporting cells. In addition, from the beginning of day 2 PH, we observed cells with highly similar characteristics to those of CCs (absence of knob, abundant mitochondria and filamentous material in apical cytoplasm, numerous microtubules, and envelopment by supporting cells) but with cilia still remaining on their noninvaginated apical surface. We conclude that these cells may correspond to immature CCs in which the crypt, the final feature of their morphological differentiation, has not yet formed.

Wharton's Jelly Stem Cells: A Novel Cell Source for Oral Mucosa and Skin Epithelia Regeneration

Perinatal stem cells such as human umbilical cord Whartons jelly stem cells (HWJSCs) are excellent candidates for tissue engineering because of their proliferation and differentiation capabilities. However, their differentiation potential into epithelial cells at in vitro and in vivo levels has not yet been reported. In this work we have studied the capability of HWJSCs to differentiate in vitro and in vivo to oral mucosa and skin epithelial cells using a bioactive three‐dimensional model that mimics the native epithelial‐mesenchymal interaction. To achieve this, primary cell cultures of HWJSCs, oral mucosa, and skin fibroblasts were obtained in order to generate a three‐dimensional heterotypical model of artificial oral mucosa and skin based on fibrin‐agarose biomaterials. Our results showed that the cells were unable to fully differentiate to epithelial cells in vitro. Nevertheless, in vivo grafting of the bioactive three‐dimensional models demonstrated that HWJSCs were able to stratify and to express typical markers of epithelial differentiation, such as cytokeratins 1, 4, 8, and 13, plakoglobin, filaggrin, and involucrin, showing specific surface patterns. Electron microscopy analysis confirmed the presence of epithelial cell‐like layers and well‐formed cell‐cell junctions. These results suggest that HWJSCs have the potential to differentiate to oral mucosa and skin epithelial cells in vivo and could be an appropriate novel cell source for the development of human oral mucosa and skin in tissue engineering protocols.

Histological, Histochemical and Ultrastructural Changes in the Digestive Tract of Sturgeon Acipenser naccarii During Early Ontogeny

Besides species diversification, current priorities in aquiculture include the development of suitable inert diets to enable the artificial feeding of fish from the onset of exogenous feeding. Achieving this aim demands knowledge of the structural and functional characteristics of the digestive tract throughout ontogeny. This chapter provides a histological, histochemical and ultrastructural analysis of the digestive tract of Acipenser naccarii sturgeons during different ontogenic development stages (lecithotrophic, lecithoexotrophic and exotrophic periods). These data are essential to our understanding of the digestive capacity of this species during the first stages of life. The knowledge gained will be useful for the investigation and design of appropriate diets to optimize the farming of this species, an activity of major ecological and economic importance.

Structural Characteristics and Development of Ampullary Organs in Acipenser naccarii

Ampullary organs of Acipenser naccarii sturgeons were examined by optical and electronic microscopy (transmission electron microscopy and scanning electron microscopy) from hatching until 1 month later when the juvenile phase is completely established. It was observed that, when A. naccarii begins to feed actively, the ultrastructural characteristics of ampullary organs already correspond to those of adult animals. These organs may, therefore, be functional and, together with taste buds, facilitate food search after exhaustion of yolk sac food reserves. Mature ampullary organs of A. naccarii are formed by an ampulla that communicates with the exterior by means of a short channel. These ampullae correspond to the sensory portion of these receptors and are formed by two cell types: receptor cells and support cells. Receptor cells present a kinocilium on their free surface and establish ribbon synapses with axon nerve endings that arise from the underlying conjunctive tissue. Support cells enclose receptor cells, bear stereocilia and occasional cilia, and are of a secretory nature. The mucus associated with ampullary organs mainly comprises neutral mucopolysaccharides, whereas mucopolysaccharides are usually acid in other fish groups. Anat Rec, 290:1178–1189, 2007.