Cytochemical and immunocytochemical investigations on epidermal mitochondria-rich cells in Salamandra salamandra salamandra (L.) larvae

The adaptive microbiome hypothesis and immune interactions in amphibian mucus

The microbiome is known to provide benefits to hosts, including extension of immune function. Amphibians are a powerful immunological model for examining mucosal defenses because of an accessible epithelial mucosome throughout their developmental trajectory, their responsiveness to experimental treatments, and direct interactions with emerging infectious pathogens. We review amphibian skin mucus components and describe the adaptive microbiome as a novel process of disease resilience where competitive microbial interactions couple with host immune responses to select for functions beneficial to the host. We demonstrate microbiome diversity, specificity of function, and mechanisms for memory characteristic of an adaptive immune response. At a time when industrialization has been linked to losses in microbiota important for host health, applications of microbial therapies such as probiotics may contribute to immunotherapeutics and to conservation efforts for species currently threatened by emerging diseases.

Lectin binding properties of liver, small intestine and tail of metamorphosing marsh frog (Pelophylax ridibundus Pallas 1771)

In this present study, localization and variations of specific sugar moieties in the terminal carbohydrate chains of glycoconjugates in the small intestine, liver and tail have been investigated during the metamorphosis of Pelophylax ridibundus larvae. For this purpose, four lectins were used: wheat germ agglutinin (WGA), Ulex europaeus agglutinin (UEA-I), Dolichos biflorus agglutinin (DBA) and peanut agglutinin (PNA), in different larval stages of the frog. Some cells stained specifically in the intestinal mucosa and in tail epidermal cells with the lectins and their affinity changed during metamorphic transformation. For the most part, they decreased in the climax and postmetamorphic periods. It was also found that WGA, DBA and UEA-I lectins exhibited strong affinity to white blood cells in the liver and their binding affinities were the highest in prometamorphosis and they gradually decreased until the end of metamorphosis. These results suggest that the changes of lectin binding in metamorphosis may be an indication of some cellular events occurring in larval metamorphosis such as cell differentiation and damage of cell adhesion between death and differentiating cells. They also can be useful markers for detection of white blood cells in amphibian hematopoietic organs.

Lectin binding patterns in amphibian skin epithelium

Seven lectins (PNA, DBA, WGA, UEA-I, RCA, SBA, Con A) were used to localize glycoconjugates in the skin of 10 species of Amphibia, 7 anurans (Bufo marinus, Bufo bufo, Rana ridibunda, Rana pipiens, Hyla arborea, Pelobates syriacus and Xenopus laevis) and 3 urodeles (Salamandra salamandra, Triturus vulgaris and Ambystoma mexicanum). It was found that every lectin has a specific binding pattern in the skin of each species. No common pattern could be established, either among frogs or toads, nor for a particular lectin. Each lectin bound specifically and selectively to a particular epithelial component, which differed from one species to the other. A number of lectins showed selective binding to mitochondria-rich cells, but, again, a pattern in positivity could not be found. It is concluded that lectin histochemistry does correlate with cellular function. Our data can be applied in studies of epithelium and skin development, and of changes that occur during adaptation to the environment by amphibian species.