Histochemical studies of chondrogenesis

The formation of the cartilage tissue depends on the coordination of cell to cell or cell to ECM interaction that cause to the cell polarity, migration and differentiation of precursor mesenchymal cells during chondrogenesis Many of these events are mediated by ECM components such as glycocojugates which with their suger residues such as galactose or aminosuger have a ligand role for regulatory molecules. The aim of this study was to identify the presence and distribution of some different glycoconjugates and their suger residues in the chondrogenesis by histochemistry and lectin-histochemistry techniques. For this purpose, embryos from pregnant wistar rats from E12-E20 were collected and fixed. Some of them were stained with alizarin red Salcin blue staining to demonstrate cartilage and bone formation in whole mount embryos. Other embryos with serial sections (5-7micm thikness) were stained by: 1-alcian blue (pH: l) for S-GAG,2-alcin blue (pH:2.5)for C-GAG, S-PAS alcian blue fora neutral and acidic sugers,4- tuloidin blue for metachromatic substances. Stained sections were graded according to the staining intensity (0-5 grading s method). Statistical analysis showed significant difference for those substances among experimental groups. Lectin histochemistry with MPA, VVA, SBA, OFA demonstrated differences between organs for suger residues during chondrogensis. It seems that synthesis and secretion of glycocojugates and change of their suger residues follows a spatiotemporal pattern and developmentaly regulated.

Assessment of seawater pollution by heavy metals (lead & cadmium) in the Qeshm rocky shore: use of the sea urchin, Echinometra mathaei, as a bioindicator

The general purpose of this study is to investigate the degree of heavy metal accumulation in hard and soft tissue of sea urchin, and determining these tissues as the most suitable bioindicator for lead and cadmium in the environment of the sampling stations. The way of doing this assessment was MOOPAM. Samples were prepared and classified according to sea urchin organ (soft tissue, hard tissue, Tube feet, Test, Lantern Structure and spines) and then lead and cadmium were measured in them. Result of this study shows that hard tissue is a better index of lead and cadmium than soft tissue. The result of bioaccumulation of lead in the related tissue was found to be in the following order: Soft tissue=21, hard tissue=28.1, Test=20.8, Lantern Structure=20.5 and spines=23.9. The result of bioaccumulation of cadmium in the related tissue was found to be in the following order: Soft tissue=9. 7, hard tissue=5.01, Test=4.2, Lantern Structure=4.06 and spines=5.53.